Propeptide

Distribution by Scientific Domains

Kinds of Propeptide

  • amino-terminal propeptide
  • n-terminal propeptide


  • Selected Abstracts


    Positive Linear Growth and Bone Responses to Growth Hormone Treatment in Children With Types III and IV Osteogenesis Imperfecta: High Predictive Value of the Carboxyterminal Propeptide of Type I Procollagen,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003
    Joan C Marini MD
    Abstract Extreme short stature is a cardinal feature of severe osteogenesis imperfecta (OI), types III and IV. We conducted a treatment trial of growth hormone in children with OI and followed linear growth velocity, bone metabolism markers, histomorphometrics, and vertebral bone density. Twenty-six children with types III and IV OI, ages 4.5,12 years, were treated with recombinant growth hormone (rGH), 0.1,0.2 IU/kg per day for 6 days/week, for at least 1 year. Length, insulin-like growth factor (IGF-I), insulin-like growth factor binding protein (IGFBP-3), bone metabolic markers, and vertebral bone density by DXA were evaluated at 6-month intervals. An iliac crest biopsy was obtained at baseline and 12 months. Approximately one-half of the treated OI children sustained a 50% or more increase in linear growth over their baseline growth rate. Most responders (10 of 14) had moderate type IV OI. All participants had positive IGF-I, IGFBP-3, osteocalcin, and bone-specific alkaline phosphatase responses. Only the linear growth responders had a significant increase in vertebral DXA z-score and a significant decrease in long bone fractures. After 1 year of treatment, responders' iliac crest biopsy showed significant increases in cancellous bone volume, trabecular number, and bone formation rate. Responders were distinguished from nonresponders by higher baseline carboxyterminal propeptide (PICP) values (p < 0.05), suggesting they have an intrinsically higher capacity for collagen production. The results show that growth hormone can cause a sustained increase in the linear growth rate of children with OI, despite the abnormal collagen in their bone matrix. In the first year of treatment, growth responders achieve increased bone formation rate and density, and decreased fracture rates. The baseline plasma concentration of PICP was an excellent predictor of positive response. [source]


    Transcriptional profiling of brain-derived-neurotrophic factor-induced neuronal plasticity: A novel role for nociceptin in hippocampal neurite outgrowth

    DEVELOPMENTAL NEUROBIOLOGY, Issue 4 2006
    Robert H. Ring
    Abstract Brain derived neurotrophic factor (BDNF) exhibits a sequence of actions on neurons ranging from acute enhancement of transmission to long-term promotion of neurite outgrowth and synaptogenesis associated with learning and memory. The manifold effects of BDNF on neuronal modifications may be mediated by genomic alterations. We previously found that BDNF treatment acutely increases transcription of the synaptic vesicle protein Rab3A, required for trophin-induced synaptic plasticity, as well as the peptide VGF, which increases during learning. To elucidate comprehensive transcriptional programs associated with short- and long-term BDNF exposure, we now examine mRNA abundance and complexity using Affymetrix GeneChips in cultured hippocampal neurons. Consistent with the modulation of synaptic plasticity, BDNF treatment (3,6 h) induced mRNAs encoding the synapse-associated proteins synaptojanin 2, neuronal pentraxin 1, septin 9, and ryanodine receptor 2. BDNF also induced expression of mRNAs encoding neuropeptides (6,12 h), including prepronociceptin, neuropeptide Y, and secretogranin. To determine whether these neuropeptides induced by BDNF mediate neuronal development, we examined their effects on hippocampal neurons. The four mature peptides derived from post-translational processing of the ppNociceptin propeptide induced the expression of several immediate early genes in hippocampal cultures, indicating neuronal activation. To examine the significance of activation, the effects of nociceptin (orphanin FQ) and nocistatin on neurite outgrowth were examined. Quantitative morphometric analysis revealed that nociceptin significantly increased both average neurite length and average number of neurites per neuron, while nocistatin had no effect on these parameters. These results reveal a novel role for nociceptin and suggest that these neuropeptide systems may contribute to the regulation of neuronal function by BDNF. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]


    Type I collagen markers in cord serum of appropriate vs. small for gestational age infants born during the second half of pregnancy

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2001
    T. Saarela
    Background The serum concentration of the N-terminal propeptide of type I procollagen (PINP) reflects the synthesis rate of type I collagen, whereas the corresponding C-terminal telopeptide (ICTP) mirrors its degradation. Design PINP and ICTP were measured in a total of 690 cord serum samples from 592 appropriate-for-gestational-age (AGA) infants and 98 smal-for-gestational-age (SGA) infants. These markers were compared between AGA and SGA infants of different gestational ages, ranging from 23 to 41 weeks, and birth weights, from 620 to 4555 g. Results Both PINP and ICTP levels were very high in the preterm AGA infants and declined significantly with advancing gestational age, paralleling the shape of the fetal growth velocity curve. Regardless of the quite large interindividual variations observed in these markers, PINP was significantly lower in both the preterm and term AGA infants than in the SGA infants. This was also the case for ICTP in the preterm infants of gestational age less than 36 weeks. In stepwise multiple regression analyses, gestational age, being either AGA or SGA and head circumference were significant factors to explain the levels of PINP and ICTP. The levels of PINP and ICTP were correlated with each other highly significantly in both the AGA and SGA infants (rs = 0·700 and 0·692, respectively; P < 0·001 in both). Conclusions The levels of type I collagen markers seem to follow closely the shape of the fetal growth velocity curve during different stages of gestation. However, because of the large interindividual variations observed, further studies are needed before the significance of these markers for the assessment of normal and abnormal fetal growth can be established. [source]


    First-line treatment with bortezomib rapidly stimulates both osteoblast activity and bone matrix deposition in patients with multiple myeloma, and stimulates osteoblast proliferation and differentiation in vitro

    EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2010
    Thomas Lund
    Abstract Objectives:, The aim of the study was to investigate the effect of bortezomib on osteoblast proliferation and differentiation, as well as on bone matrix deposition for the first time in bisphosphonate-naïve, previously untreated patients with myeloma. Methods:, Twenty newly diagnosed patients received four cycles of bortezomib treatment, initially as monotherapy and then combined with a glucocorticoid from cycle two to four. Bone remodeling markers were monitored closely during treatment. Furthermore, the effects of bortezomib and a glucocorticoid on immature and mature osteoblasts were also studied in vitro. Results:, Treatment with bortezomib caused a significant increase in bone-specific alkaline phosphatase and pro-collagen type I N-terminal propeptide, a novel bone formation marker. The addition of a glucocorticoid resulted in a transient decrease in collagen deposition. In vitro bortezomib induced osteoblast proliferation and differentiation. Differentiation but not proliferation was inhibited by glucocorticoid treatment. Conclusions:, Bortezomib used as first-line treatment significantly increased collagen deposition in patients with multiple myeloma and osteolytic lesions, but the addition of a glucocorticoid to the treatment transiently inhibited the positive effect of bortezomib, suggesting that bortezomib may result in better healing of osteolytic lesions when used without glucocorticoids in patients that have obtained remission with a previous therapy. The potential bone-healing properties of single-agent bortezomib are currently being explored in a clinical study in patients who have undergone high-dose therapy and autologous stem cell transplantation. [source]


    The C-terminal region of the proprotein convertase 1/3 (PC1/3) exerts a bimodal regulation of the enzyme activity in vitro

    FEBS JOURNAL, Issue 13 2007
    Nadia Rabah
    The proprotein convertase PC1/3 preferentially cleaves its substrates in the dense core secretory granules of endocrine and neuroendocrine cells. Similar to most proteinases synthesized first as zymogens, PC1/3 is synthesized as a larger precursor that undergoes proteolytic processing of its signal peptide and propeptide. The N-terminally located propeptide has been shown to be essential for folding and self-inhibition. Furthermore, PC1/3 also possesses a C-terminal region (CT-peptide) which, for maximal enzymatic activity, must also be cleaved. To date, its role has been documented through transfection studies in terms of sorting and targeting of PC1/3 and chimeric proteins into secretory granules. In this study, we examined the properties of a 135-residue purified bacterially produced CT-peptide on the in vitro enzymatic activity of PC1/3. Depending on the amount of CT-peptide used, it is shown that the CT-peptide increases PC1/3 activity at low concentrations (nm) and decreases it at high concentrations (µm), a feature typical of an activator. Furthermore, we show that, contrary to the propeptide, the CT-peptide is not further cleaved by PC1/3 although it is sensitive to human furin activity. Based on these results, it is proposed that PC1/3, through its various domains, is capable of controlling its enzymatic activity in all regions of the cell that it encounters. This mode of self-control is unique among members of all proteinases families. [source]


    Novel ,-carboxyglutamic acid-containing peptides from the venom of Conus textile

    FEBS JOURNAL, Issue 12 2006
    Eva Czerwiec
    The cone snail is the only invertebrate system in which the vitamin K-dependent carboxylase (or ,-carboxylase) and its product ,-carboxyglutamic acid (Gla) have been identified. It remains the sole source of structural information of invertebrate ,-carboxylase substrates. Four novel Gla-containing peptides were purified from the venom of Conus textile and characterized using biochemical methods and mass spectrometry. The peptides Gla(1),TxVI, Gla(2),TxVI/A, Gla(2),TxVI/B and Gla(3),TxVI each have six Cys residues and belong to the O -superfamily of conotoxins. All four conopeptides contain 4- trans -hydroxyproline and the unusual amino acid 6- l -bromotryptophan. Gla(2),TxVI/A and Gla(2),TxVI/B are isoforms with an amidated C-terminus that differ at positions +1 and +13. Three isoforms of Gla(3),TxVI were observed that differ at position +7: Gla(3),TxVI, Glu7,Gla(3),TxVI and Asp7-Gla(3),TxVI. The cDNAs encoding the precursors of the four peptides were cloned. The predicted signal sequences (amino acids ,46 to ,27) were nearly identical and highly hydrophobic. The predicted propeptide region (,20 to ,1) that contains the ,-carboxylation recognition site (,-CRS) is very similar in Gla(2),TxVI/A, Gla(2),TxVI/B and Gla(3),TxVI, but is more divergent for Gla(1),TxVI. Kinetic studies utilizing the Conus,-carboxylase and synthetic peptide substrates localized the ,-CRS of Gla(1),TxVI to the region ,14 to ,1 of the polypeptide precursor: the Km was reduced from 1.8 mm for Gla (1),TxVI lacking a propeptide to 24 µm when a 14-residue propeptide was attached to the substrate. Similarly, addition of an 18-residue propeptide to Gla(2),TxVI/B reduced the Km value tenfold. [source]


    Head-to-head comparison of risedronate vs. teriparatide on bone turnover markers in women with postmenopausal osteoporosis: a randomised trial

    INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 6 2008
    A. D. Anastasilakis
    Summary Aims:, We aimed to compare the effect of risedronate (RIS) and teriparatide (TPTD) (recombinant human parathyroid hormone 1,34) on bone turnover markers in women with postmenopausal osteoporosis. Methods:, Forty-four Caucasian women (age 65.1 ± 1.6 years) with postmenopausal osteoporosis were randomly assigned to receive either RIS 35 mg once weekly (n = 22) or TPTD 20 ,g once daily (n = 22) for 12 months. Serum N-terminal propeptide of type 1 collagen (P1NP), C-terminal telopeptide of type 1 collagen (CTx), total alkaline phosphatase (ALP) and intact parathyroid hormone (iPTH) were obtained from all women before, 3 and 6 months after treatment initiation. Lumbar spine bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry before and 12 months after treatment initiation. Results:, P1NP, CTx and total ALP levels decreased in RIS group (p < 0.001) and increased in TPTD group (p < 0.001) throughout the treatment. iPTH increased significantly in RIS group (p < 0.05) and decreased in TPTD group (p < 0.001). Finally, lumbar spine BMD increased significantly in both RIS (p = 0.003) and TPTD groups (p < 0.001) without significant differences between them. Conclusions:, Our data suggest that both serum P1NP and CTx are reliable markers of RIS and TPTD action in women with postmenopausal osteoporosis. In a similar way, serum total ALP can be used as an alternative marker for monitoring both RIS and TPTD action, while iPTH can be used only for TPTD-treated women. The increase in P1NP and CTx after 3 months of treatment with RIS or TPTD can predict the increase in BMD after 12 months of treatment. [source]


    Molecular cloning, genomic organization and functional characterization of a new short-chain potassium channel toxin-like peptide BmTxKS4 from Buthus martensii Karsch(BmK)

    JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2004
    Sheng Jiqun
    Abstract Scorpion venom contains many small polypeptide toxins, which can modulate Na+, K+, Cl,, and Ca2+ ion,channel conductance in the cell membrane. A full-length cDNA sequence encoding a novel type of K+ -channel toxin (named BmTxKS4) was first isolated and identified from a venom gland cDNA library of Buthus martensii Karsch (BmK). The encoded precursor contains 78 amino acid residues including a putative signal peptide of 21 residues, propeptide of 11 residues, and a mature peptide of 43 residues with three disulfide bridges. BmTxKS4 shares the identical organization of disulfide bridges with all the other short-chain K+ -channel scorpion toxins. By PCR amplification of the genomic region encoding BmTxKS4, it was shown that BmTxKS4 composed of two exons is disrupted by an intron of 87 bp inserted between the first and the second codes of Phe (F) in the encoding signal peptide region, which is completely identical with that of the characterized scorpion K+ -channel ligands in the size, position, consensus junctions, putative branch point, and A+T content. The GST-BmTxKS4 fusion protein was successfully expressed in BL21 (DE3) and purified with affinity chromatography. About 2.5 mg purified recombinant BmTxKS4 (rBmTxKS4) protein was obtained by treating GST-BmTxKS4 with enterokinase and sephadex chromatography from 1 L bacterial culture. The electrophysiological activity of 1.0,M rBmTxKS4 was measured and compared by whole cell patch-clamp technique. The results indicated that rBmTxKS4 reversibly inhibited the transient outward K+ current (Ito), delayed inward rectifier K+ current (Ik1), and prolonged the action potential duration of ventricular myocyte, but it has no effect on the action potential amplitude. Taken together, BmTxKS4 is a novel subfamily member of short-strain K+ -channel scorpion toxin. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:187,195, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20026 [source]


    Genetic variation in the RANKL/RANK/OPG signaling pathway is associated with bone turnover and bone mineral density in men

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2010
    Delnaz Roshandel
    Abstract The aim of this study was to determine if single-nucleotide polymorphisms (SNPs) in RANKL, RANK, and OPG influence bone turnover and bone mineral density (BMD) in men. Pairwise tag SNPs (r2,,,0.8) were selected for RANKL, RANK, and OPG and their 10-kb flanking regions. Selected tag SNPs plus five SNPs near RANKL and OPG, associated with BMD in published genome-wide association studies (GWAS), were genotyped in 2653 men aged 40 to 79 years of age recruited for participation in a population-based study of male aging, the European Male Ageing Study (EMAS). N-terminal propeptide of type I procollagen (PINP) and C-terminal cross-linked telopeptide of type I collagen (CTX-I) serum levels were measured in all men. BMD at the calcaneus was estimated by quantitative ultrasound (QUS) in all men. Lumbar spine and total-hip areal BMD (BMDa) was measured by dual-energy X-ray absorptiometry (DXA) in a subsample of 620 men. Multiple OPG, RANK, and RANKL SNPs were associated with bone turnover markers. We also identified a number of SNPs associated with BMD, including rs2073618 in OPG and rs9594759 near RANKL. The minor allele of rs2073618 (C) was associated with higher levels of both PINP (,,=,1.83, p,=,.004) and CTX-I (,,=,17.59, p,=,4.74,×,10,4), and lower lumbar spine BMDa (,,=,,0.02, p,=,.026). The minor allele of rs9594759 (C) was associated with lower PINP (,,=,,1.84, p,=,.003) and CTX-I (,,=,,27.02, p,=,6.06,×,10,8) and higher ultrasound BMD at the calcaneus (,,=,0.01, p,=,.037). Our findings suggest that genetic variation in the RANKL/RANK/OPG signaling pathway influences bone turnover and BMD in European men. © 2010 American Society for Bone and Mineral Research [source]


    Effect of Blockade of TNF-, and Interleukin-1 Action on Bone Resorption in Early Postmenopausal Women,,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2007
    Natthinee Charatcharoenwitthaya
    Abstract After acute estrogen withdrawal in postmenopausal women, administration of anakinra or etanercept, specific blockers of IL-1 and TNF-,, respectively, reduced the rise in bone resorption markers to about one half of that in controls. This is consistent with an important role for these immune cytokines in mediating the effect of estrogen deficiency on bone. Introduction: Studies in rodents have implicated increased production of interleukin (IL)-1, and TNF-, as mediators of bone loss after ovariectomy, but their roles are unclear in humans whose immune system differs markedly from that of rodents. Materials and Methods: We administered transdermal estradiol, 0.1 mg/d, for 60 days to 42 early postmenopausal women. Estrogen treatment was discontinued, and subjects were randomly assigned to intervention groups receiving 3 wk of injections with 0.9% saline, anakinra 100 mg/d, or etanercept 25 mg/twice weekly. Bone turnover was assessed by measuring serum carboxyl-terminal telopeptide of type 1 collagen (CTX) and amino-terminal telopeptide of type 1 collagen (NTX), markers for bone resorption, and serum amino-terminal propeptide of type 1 collagen (P1NP), a marker for bone formation. Results were expressed as percent change in markers from baseline (last 2 days of estrogen treatment and days 20 and 21 of intervention). Results: The percent changes from baseline during intervention for serum CTX, urine NTX, and serum PINP, respectively, were 43.3 ± 8.0%, 12.0 ± 7.1%, and ,41.0 ± 2.5% for the control group; 25.9 ± 6.3%, 9.5 ± 4.0%, and ,37.8 ± 3.0% for the anakinra group; and 21.7 ± 5.0%, 0.32 ± 3.82%, and ,34.5 ± 3.9% for the etanercept group. Compared with the control group, the blunting of the increase in serum CTX fell just below the level of significance (p = 0.10) after anakinra treatment, whereas the blunting of the increase in serum CTX (p = 0.034) and in urine NTX (p = 0.048) were significant after etanercept treatment. Other changes were not significant. Conclusions: The data are consistent with a role for TNF-,, and possibly for IL-1,, in mediating increased bone resorption during estrogen deficiency in women. Although either cytokine blocker reduced serum CTX by about one half, the effect of combined blockade could not be tested because of concerns about toxicity. The data do not exclude direct or indirect contributory roles for RANKL or for other cytokines. [source]


    Pretreatment Levels of Bone Turnover and the Antifracture Efficacy of Alendronate: The Fracture Intervention Trial

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2006
    Douglas C Bauer MD
    Abstract The influence of pretreatment bone turnover on alendronate efficacy is not known. In the FIT, we examined the effect of pretreatment bone turnover on the antifracture efficacy of daily alendronate given to postmenopausal women. The nonspine fracture efficacy of alendronate was significantly greater among both osteoporotic and nonosteoporotic women with higher baseline levels of the bone formation marker PINP. Introduction: Previous trials have shown that high bone turnover is associated with greater increases in BMD among bisphosphonate-treated women. The influence of pretreatment bone turnover levels on antifracture efficacy has not been well studied. Materials and Methods: We randomized women 55,80 years of age with femoral neck BMD T scores , ,1.6 to alendronate (ALN), 5,10 mg/day (n = 3105), or placebo (PBO; n = 3081). At baseline, 3495 women were osteoporotic (femoral neck BMD T score , ,2.5 or prevalent vertebral fracture), and 2689 were not osteoporotic (BMD T score > ,2.5 and no prevalent vertebral fracture). Pretreatment levels of bone-specific alkaline phosphatase (BSALP), N-terminal propeptide of type 1 collagen (PINP), and C-terminal cross-linked telopeptide of type 1 collagen (sCTx) were measured in all participants using archived serum (20% fasting). The risk of incident spine and nonspine fracture was compared in ALN- and PBO-treated subjects stratified into tertiles of baseline bone marker level. Results and Conclusions: During a mean follow-up of 3.2 years, 492 nonspine and 294 morphometric vertebral fractures were documented. Compared with placebo, the reduction in nonspine fractures with ALN treatment differed significantly among those with low, intermediate, and high pretreatment levels of PINP levels (p = 0.03 for trend). For example, among osteoporotic women in the lowest tertile of pretreatment PINP (<41.6 ng/ml), the ALN versus PBO relative hazard for nonspine fracture was 0.88 (95% CI: 0.65, 1.21) compared with a relative hazard of 0.54 (95% CI: 0.39, 0.74) among those in the highest tertile of PINP (>56.8 ng/ml). Results were similar among women without osteoporosis at baseline. Although they did not reach statistical significance, similar trends were observed with baseline levels of BSALP. Conversely, spine fracture treatment efficacy among osteoporotic women did not differ significantly according to pretreatment marker levels. Spine fracture treatment efficacy among nonosteoporotic women was related to baseline BSALP (p = 0.05 for trend). In summary, alendronate nonspine fracture efficacy is greater among both osteoporotic and nonosteoporotic women with high pretreatment PINP. If confirmed in other studies, these findings suggest that bisphosphonate treatment may be most effective in women with elevated bone turnover. [source]


    Serum TRACP 5b Is a Useful Marker for Monitoring Alendronate Treatment: Comparison With Other Markers of Bone Turnover,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2005
    Arja Nenonen MSc
    Abstract We studied clinical performance of serum TRACP 5b and other bone turnover markers, including S-CTX, U-DPD, S-PINP, S-BALP, and S-OC, for monitoring alendronate treatment. TRACP 5b had higher clinical sensitivity, area under the ROC curve, and signal-to-noise ratio than the other markers. Introduction: The purpose of this study was to compare the clinical performance of serum TRACP 5b (S-TRACP5b) with that of other markers of bone turnover in the monitoring of alendronate treatment. Materials and Methods: This double-blinded study included 148 healthy postmenopausal women that were randomly assigned into two groups: one receiving 5 mg alendronate daily (n = 75) and the other receiving placebo (n = 73) for 12 months. All individuals in both groups received calcium and vitamin D daily. The bone resorption markers S-TRACP5b, serum C-terminal cross-linked telopeptides of type I collagen (S-CTX), and total urinary deoxypyridinoline (U-DPD), and the serum markers of bone formation procollagen I N-terminal propeptide (S-PINP), bone-specific alkaline phosphatase (S-BALP), and total osteocalcin (S-OC) were assessed at baseline and at 3, 6, and 12 months after initiation of treatment. Lumbar spine BMD (LBMD) was measured at baseline and 12 months. Results: Compared with the placebo group, LBMD increased, and all bone markers decreased significantly more in the alendronate group (p < 0.001 for each parameter). The decrease of S-TRACP5b after first 3 months of alendronate treatment correlated significantly with the changes of all other markers except S-OC, the best correlation being with S-CTX (r = 0.60, p < 0.0001). The changes of LBMD at 12 months only correlated significantly with the changes of S-TRACP5b (r = ,0.32, p = 0.005) and S-CTX (r = ,0.24, p = 0.037) at 3 months. Based on clinical sensitivity, receiver operating characteristic (ROC) curves, and signal-to-noise ratio, S-TRACP5b, S-CTX, and S-PINP were the best markers for monitoring alendronate treatment. Clinical sensitivity, area under the ROC curve, and signal-to-noise ratio were higher for S-TRACP5b than for the other markers. Conclusion: These results show that S-TRACP5b, S-CTX, and S-PINP are useful markers for monitoring alendronate treatment. [source]


    Differential Effects of Teriparatide and Alendronate on Bone Remodeling in Postmenopausal Women Assessed by Histomorphometric Parameters,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2005
    Monique Arlot MD
    Abstract An 18-month randomized double-blind study was conducted in postmenopausal women with osteoporosis to compare the effects of once-daily teriparatide 20 ,g with alendronate 10 mg on bone histomorphometry. Biopsies were obtained from 42 patients. Indices of bone formation were significantly higher after 6 or 18 months of teriparatide compared with alendronate treatment. Introduction: Alendronate and teriparatide increased BMD, assessed by DXA, by different mechanisms of action, supported by changes in biochemical markers of bone turnover. The purpose of this cross-sectional study was to explore the differential effects of these two osteoporosis treatments at the bone tissue level by examining bone histomorphometric parameters of bone turnover after either 6 or 18 months of treatment. Materials and Methods: Patients were a cohort from a randomized parallel double-blind study conducted to compare the effects of once-daily teriparatide 20 ,g and alendronate 10 mg in postmenopausal women with osteoporosis. Transiliac crest bone biopsies were obtained after tetracycline double labeling from 42 patients treated for 6 months (n = 23) or 18 months (n = 14); 5 additional patients were biopsied from contralateral sides at 6 and 18 months. Biopsy specimens adequate for quantitative analysis were analyzed by 2D histomorphometry from 17 patients at 6 months (teriparatide, n = 8; alendronate, n = 9) and 15 patients at 18 months (teriparatide, n = 8; alendronate, n = 7). Data were analyzed by two-sample tests. Results: Histomorphometric indices of bone formation were significantly and markedly greater in the teriparatide group than in the alendronate group at 6 and 18 months, whereas indices of bone resorption were only significantly greater in the teriparatide group than in the alendronate group at 6 months. Bone formation and activation frequency were significantly lower at 18 months compared with 6 months in the teriparatide group, returning to levels comparable with untreated postmenopausal women. In the teriparatide group, the peak in histomorphometric bone formation indices coincided with peak levels for N-terminal propeptide of type I collagen, a biochemical marker of bone formation. The degree of mineralization was lower at 18 months than at 6 months with treatment in both groups but was not different between groups. Conclusions: These results confirm the opposite mechanisms of action of teriparatide and alendronate on bone remodeling and confirm the bone formation effect of teriparatide. [source]


    Effects of Low-Dose Prednisone on Bone Metabolism,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2005
    Francine N Ton MD
    Abstract Prednisone 5 mg/day suppresses multiple indices of bone formation in a randomized placebo-controlled trial in healthy postmenopausal females. This suggests that even low doses of prednisone may reduce bone repair or renewal and may have adverse effects on bone mass and/or bone strength. Introduction: High doses of chronic glucocorticoids are known to have adverse effects on bone, and measures to prevent bone loss are well established for doses >7.5 mg daily, because these doses can cause premature or exaggerated osteoporosis. However, it is unclear if chronic prednisone doses of 5 mg daily have the same effects on bone. There are no established recommendations for preventing glucocorticoid-induced osteoporosis in people taking prednisone 5 mg daily, a dose used frequently in medical practice to treat diseases of the lungs, joints, skin, muscles, eyes, nerves, etc. Our primary objective was to test whether prednisone 5 mg daily affects serum and urine indices of bone metabolism in healthy postmenopausal women. Our secondary objectives were to determine if prednisone 5 mg affected systolic or diastolic blood pressure or causes side effects. Materials and Methods: A double-blinded randomized placebo-controlled 8-week trial in 50 healthy postmenopausal women was conducted at the Massachusetts General Hospital Outpatient General Clinical Research Center. Patients were randomly assigned to prednisone 5 mg daily or matching placebo for 6 weeks, followed by a 2-week recovery phase. Markers of bone formation and resorption were determined at weeks 0, 2, 4, 6, and 8. Indices of osteoblast activity included serum propeptide of type I N-terminal procollagen (PINP), propeptide of type I C-terminal procollagen (PICP), osteocalcin, and bone-specific alkaline phosphatase (BSALP). Indices of osteoclast activity included urine and serum type I collagen N-telopeptide (NTX) and free urinary deoxypyridinoline (DPD). Results and Conclusions: Prednisone rapidly and significantly decreased serum PINP (p < 0.01), PICP (p < 0.01), and osteocalcin (p < 0.01) and free urinary deoxypyridinoline (p = 0.017). These changes were largely reversed during the recovery period. Side effects were indistinguishable in the two groups. Neither systolic nor diastolic blood pressure changed significantly throughout the study between the two groups. In conclusion, low-dose prednisone significantly decreases indices of bone formation and may decrease indices of bone resorption in postmenopausal women. Further studies are needed to assess the effects of low-dose prednisone on BMD and fracture risk. [source]


    Positive Linear Growth and Bone Responses to Growth Hormone Treatment in Children With Types III and IV Osteogenesis Imperfecta: High Predictive Value of the Carboxyterminal Propeptide of Type I Procollagen,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003
    Joan C Marini MD
    Abstract Extreme short stature is a cardinal feature of severe osteogenesis imperfecta (OI), types III and IV. We conducted a treatment trial of growth hormone in children with OI and followed linear growth velocity, bone metabolism markers, histomorphometrics, and vertebral bone density. Twenty-six children with types III and IV OI, ages 4.5,12 years, were treated with recombinant growth hormone (rGH), 0.1,0.2 IU/kg per day for 6 days/week, for at least 1 year. Length, insulin-like growth factor (IGF-I), insulin-like growth factor binding protein (IGFBP-3), bone metabolic markers, and vertebral bone density by DXA were evaluated at 6-month intervals. An iliac crest biopsy was obtained at baseline and 12 months. Approximately one-half of the treated OI children sustained a 50% or more increase in linear growth over their baseline growth rate. Most responders (10 of 14) had moderate type IV OI. All participants had positive IGF-I, IGFBP-3, osteocalcin, and bone-specific alkaline phosphatase responses. Only the linear growth responders had a significant increase in vertebral DXA z-score and a significant decrease in long bone fractures. After 1 year of treatment, responders' iliac crest biopsy showed significant increases in cancellous bone volume, trabecular number, and bone formation rate. Responders were distinguished from nonresponders by higher baseline carboxyterminal propeptide (PICP) values (p < 0.05), suggesting they have an intrinsically higher capacity for collagen production. The results show that growth hormone can cause a sustained increase in the linear growth rate of children with OI, despite the abnormal collagen in their bone matrix. In the first year of treatment, growth responders achieve increased bone formation rate and density, and decreased fracture rates. The baseline plasma concentration of PICP was an excellent predictor of positive response. [source]


    Cross-Sectional Evaluation of Bone Metabolism in Men,

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2001
    P. Szulc
    Abstract There are relatively few data concerning age-related changes of bone turnover in men. The aim of the study was to evaluate age-related changes of the levels of serum and urinary biochemical markers of bone metabolism in a large cohort of 934 men aged 19,85 years and to investigate their association with bone mineral density (BMD). Bone formation was evaluated using serum levels of osteocalcin (OC), bone alkaline phosphatase (BAP), and N-terminal extension propeptide of type I collagen (PINP). Bone resorption was evaluated by measurement of urinary excretion of ,-isomerized C-terminal telopeptide of collagen type I (,-CTX) of free deoxypyridinoline (fDpyr) and total Dpyr (tDPyr) and of the serum level of ,-CTX. Levels of biochemical bone markers were very high in young men and decreased rapidly until the age of 40 years and then more slowly until 60 years of age. After the age of 60 years, markers of bone formation remained stable while resorption markers showed a moderate and variable increase with aging. Serum and urinary ,-CTX levels were elevated only in about 5% of elderly men. The age-related increase of urinary excretion of tDpyr and of its free and peptide-bound fractions was related to the presence of elevated levels in a subgroup of about 15% of elderly men. Before 60 years of age, levels of biochemical bone markers were not correlated with BMD, whereas after 60 years of age, they were correlated negatively with BMD. After adjustment for age and body weight, BMD in men with the highest levels of biochemical bone markers (i.e., in the upper quartile) was 1.8,12.5% (i.e., 0.25,0.89 SD) lower than in men with levels of biochemical bone markers in the lowest quartile. In conclusion, bone turnover in men is high in young adults and decreases to reach a nadir at 55,60 years of age. After the age of 60 years, bone resorption markers,but not bone formation markers,increase in some men and are associated with lower BMD, suggesting that this imbalance is responsible for increasing bone loss in elderly men. [source]


    A Detailed Assessment of Alterations in Bone Turnover, Calcium Homeostasis, and Bone Density in Normal Pregnancy

    JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2000
    A. J. Black
    Abstract The effects of pregnancy on bone turnover and the potential risk of developing an osteoporotic fracture in pregnancy are controversial. Utilizing biochemical markers of bone formation and resorption and dual-energy X-ray absorptiometry (DEXA), bone turnover before, during, and after pregnancy was studied in detail. Ten women (mean age 30 years; range 23,40) were recruited. Prepregnancy data were obtained and then a review was performed at 2-week intervals, once pregnancy was confirmed, until 14 weeks of gestation and thereafter monthly until term. Bone mineral density (BMD) was estimated by DEXA scanning of hip, spine, and forearm preconception and postpartum. In addition, BMD of the forearm at 14 weeks and 28 weeks gestation was obtained. All pregnancies had a successful outcome. Urinary free pyridinium cross-links, free pyridinoline (fPyr) and free deoxypyridinoline (fDPyr), were normal prepregnancy (mean [±SD]) 14.6 nmol/mmol (1.8) and 5.0 nmol/mmol (1.0) creat, respectively. By 14 weeks, they had increased to 20.8 nmol/mmol (4.3) and 6.1 nmol mmol (1.4) (both p < 0.02) and by 28 weeks to 26.3 nmol/mmol (5.6) and 7.4 nmol/mmol (1.6) (both p < 0.01). The ratio of fPyr to fDPyr remained constant. A similar significant increase was observed in N-telopeptide (NTx). Bone formation was assessed by measurement of carboxy-terminal propeptide of type 1 collagen (P1CP) and bone-specific alkaline phosphatase (BSAP). Neither were altered significantly before 28 weeks, but subsequently mean P1CP increased from 110 ,g/liter (23) to 235 ,g/liter (84) at 38 weeks and mean BSAP increased from 11.1 U/liter (5.0) to 28.6 U/liter (11.1) (p < 0.01 for both variables). Lumbar spine (L1,L4) BMD decreased from a prepregnancy mean of 1.075 g/cm (0.115) to 1.054 g/cm2 (0.150) postpartum (p < 0.05). Total hip BMD decreased from a prepregnancy mean of 0.976 g/cm2 (0.089) to 0.941 g/cm2 (0.097) (p < 0.05). Forearm BMD at midradius, one-third distal and ultradistal decreased but did not reach statistical significance. As assessed by these bone markers, in the first 2 trimesters of pregnancy, bone remodeling is uncoupled with a marked increase in bone resorption. A corresponding increase in formation markers is not observed until the third trimester. Spinal BMD exhibits a significant decrease from prepregnancy to the immediate postpartum period with a mean reduction in BMD of 3.5% in 9 months. [source]


    Serum amino-terminal propeptide of type III procollagen and 7S domain of type IV collagen correlate with hepatic iron concentration in patients with chronic hepatitis C following ,-interferon therapy

    JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2001
    Ichiro Shimizu
    Abstract Background: It has been reported that chronic infection with hepatitis C virus is associated with excess iron deposits in the liver of subjects who are neither alcoholics nor recipients of blood transfusions. However, little is known about the relationship between hepatic iron concentration (HIC) and the serum levels of hepatic fibrogenesis markers, which were caused by interferon therapy for chronic hepatitis C. Therefore, changes in the serum amino-terminal propeptide of type III procollagen (P-III-P) and the 7S domain of type IV collagen (7S-IV) in 16 patients treated with ,-interferon (IFN-,) were studied, and their HIC and histological assessment evaluated. Hepatic iron concentrations were measured by using liver biopsy specimens obtained before and 6 months after the cessation of treatment. Methods and Results: Eight subjects (50%) who had normal alanine transaminase levels at 6 months after therapy showed significantly lowered HIC, and attenuated hepatic iron staining with decreased serum levels of P-III-P and 7S-IV compared to the remaining subjects. The HIC was significantly correlated with the serum levels of P-III-P and 7S-IV in all subjects. Conclusions: These findings suggest that IFN-, treatment may decrease stimuli for fibrogenesis, at least in part, by reducing the hepatic iron deposition in patients with chronic hepatitis C. [source]


    Novel ,-conotoxins identified by gene sequencing from cone snails native to Hainan, and their sequence diversity

    JOURNAL OF PEPTIDE SCIENCE, Issue 11 2006
    Sulan Luo
    Abstract Conotoxins (CTX) from the venom of marine cone snails (genus Conus) represent large families of proteins, which show a similar precursor organization with surprisingly conserved signal sequence of the precursor peptides, but highly diverse pharmacological activities. By using the conserved sequences found within the genes that encode the ,-conotoxin precursors, a technique based on RT-PCR was used to identify, respectively, two novel peptides (LiC22, LeD2) from the two worm-hunting Conus species Conus lividus, and Conus litteratus, and one novel peptide (TeA21) from the snail-hunting Conus species Conus textile, all native to Hainan in China. The three peptides share an ,4/7 subfamily ,-conotoxins common cysteine pattern (CCX4CX7C, two disulfide bonds), which are competitive antagonists of nicotinic acetylcholine receptor (nAChRs). The cDNA of LiC22N encodes a precursor of 40 residues, including a propeptide of 19 residues and a mature peptide of 21 residues. The cDNA of LeD2N encodes a precursor of 41 residues, including a propeptide of 21 residues and a mature peptide of 16 residues with three additional Gly residues. The cDNA of TeA21N encodes a precursor of 38 residues, including a propeptide of 20 residues and a mature peptide of 17 residues with an additional residue Gly. The additional residue Gly of LeD2N and TeA21N is a prerequisite for the amidation of the preceding C -terminal Cys. All three sequences are processed at the common signal site -X-Arg- immediately before the mature peptide sequences. The properties of the ,4/7 conotoxins known so far were discussed in detail. Phylogenetic analysis of the new conotoxins in the present study and the published homologue of ,4/7 conotoxins from the other Conus species were performed systematically. Patterns of sequence divergence for the three regions of signal, proregion, and mature peptides, both nucleotide acids and residue substitutions in DNA and peptide levels, as well as Cys codon usage were analyzed, which suggest how these separate branches originated. Percent identities of the DNA and amino acid sequences of the signal region exhibited high conservation, whereas the sequences of the mature peptides ranged from almost identical to highly divergent between inter- and intra-species. Notably, the diversity of the proregion was also high, with an intermediate percentage of divergence between that observed in the signal and in the toxin regions. The data presented are new and are of importance, and should attract the interest of researchers in this field. The elucidated cDNAs of these toxins will facilitate a better understanding of the relationship of their structure and function, as well as the process of their evolutionary relationships. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd. [source]


    von Willebrand factor activation, granzyme-B and thrombocytopenia in meningococcal disease

    JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 5 2010
    M. J. HOLLESTELLE
    Summary.,Background:,During invasive meningococcal disease, severe thrombocytopenia is strongly associated with a poor outcome. Objectives:,In order to elucidate the pathophysiological mechanism behind the development of thrombocytopenia, we studied the role of von Willebrand factor (VWF) in meningococcal disease. Patients/methods:,Thirty-two children with severe meningococcal disease admitted to our university hospital were included in this study. VWF and related parameters were measured and results were correlated with the development of shock and thrombocytopenia. Results:,At admission, all patients had increased levels of (active) VWF and VWF propeptide. The highest VWF propeptide levels were observed in patients with shock, indicating acute endothelial activation. Although VWF propeptide levels in patients with shock, with or without thrombocytopenia, were similar, increased active VWF was significantly lower in patients with thrombocytopenia as compared with patients without thrombocytopenia. ADAMTS13 was moderately decreased. However, the VWF multimeric pattern was minimally increased. We assume that these findings are explained by VWF consumption and perhaps by granzyme B (GrB). In vitro experiments showed that GrB is able to cleave VWF multimers in plasma, whereas GrB was high in patients with shock, who developed thrombocytopenia. Conclusions:,Our results demonstrate that consumption of VWF, derived from endothelial cells, could be a key feature of meningococcal disease and primary to the development of thrombocytopenia during shock. [source]


    ADAMTS-13, von Willebrand factor and related parameters in severe sepsis and septic shock

    JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2007
    J. A. KREMER HOVINGA
    Summary. Background:,Insufficient control of von Willebrand factor (VWF) multimer size as a result of severely deficient ADAMTS-13 activity results in thrombotic thrombocytopenic purpura associated with microvascluar thrombosis and platelet consumption, features not seldom seen in severe sepsis and septic shock. Methods:,ADAMTS-13 activity and VWF parameters of 40 patients with severe sepsis or septic shock were compared with those of 40 healthy controls of the same age and gender and correlated with clinical findings and sepsis outcome. Results:,ADAMTS-13 activity was significantly lower in patients than in healthy controls [median 60% (range 27,160%) vs. 110% (range 63,200%); P < 0.001]. VWF parameters behaved reciprocally and both VWF ristocetin cofactor activity (RCo) and VWF antigen (VWF:Ag) were significantly (P < 0.001) higher in patients compared with controls. Neither ADAMTS-13 activity nor VWF parameters correlated with disease severity, organ dysfunction or outcome. However, a contribution of acute endothelial dysfunction to renal impairment in sepsis is suggested by the significantly higher VWF propeptide and soluble thrombomodulin levels in patients with increased creatinine values as well as by their strong positive correlations (creatinine and VWF propeptide rs = 0.484, P < 0.001; creatinine and soluble thrombomodulin rs = 0.596, P < 0.001). Conclusions:,VWF parameters are reciprocally correlated with ADAMTS-13 activity in severe sepsis and septic shock but have no prognostic value regarding outcome. [source]


    On the cutting edge: von Willebrand factor propeptide and thrombosis

    JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2006
    M. V. RAGNI
    [source]


    Non-fatal major bleeding during treatment with vitamin K antagonists: influence of soluble thrombomodulin and mutations in the propeptide of coagulation factor IX

    JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2004
    J. F. Van Der Heijden
    Summary., Background and objectives : The key complication of treatment with vitamin K antagonists (VKAs) is bleeding. The major determinant of VKA-induced bleeding is the intensity of anticoagulation. Individual patient characteristics may also influence bleeding risk. In addition, soluble thrombomodulin (s-TM) levels and mutations in the propeptide of factor (F)IX are important candidate risk factors in this respect. Patients and methods : A matched case,control study was designed to search for risk factors that predict bleeding during VKA treatment. We selected cases that had experienced major bleeding during treatment with VKA and matched controls without bleeding complications from the databases of two Thrombosis Services. The controls were matched for indication of treatment, age, gender, type of anticoagulant used and whether or not treatment with VKA was stopped. DNA and plasma were stored of all cases and controls. Results and conclusions : In total 110 patients and 220 controls consented to participate. The results indicate that s-TM levels, measured by ELISA, may be a risk indicator for bleeding [crude odds ratio 3.25 for the highest quartile vs. the lowest quartile (95% confidence interval 1.40, 7.51)]. Three novel mutations, determined by direct sequencing, in the gene portion encoding the propeptide of FIX were identified that do not seem to play an important role in bleeding risk during treatment with VKAs. [source]


    Rapid autocatalytic activation of the M4 metalloprotease aureolysin is controlled by a conserved N-terminal fungalysin-thermolysin-propeptide domain

    MOLECULAR MICROBIOLOGY, Issue 6 2008
    Nicholas N. Nickerson
    Summary The Staphylococcus aureus proteolytic cascade consists of a metalloprotease aureolysin (Aur), which activates a serine protease zymogen proSspA, which in turn activates the SspB cysteine protease. As with other M4 metalloproteases, including elastase of Pseudomonas aeruginosa, the propeptide of proAur contains an N-terminal fungalysin-thermolysin-propeptide (FTP) domain. Autocatalytic activation of proAur was initiated by processing at T85,L86 in the FTP domain. This differed from the mechanism described for proElastase, where the FTP domain has an RY motif in place of TL86, and processing occurred at the junction of the propeptide and metalloprotease domains, which remained as an inactive complex during passage across the outer membrane. When TL86 in the FTP domain was replaced with RY, an intact N-terminal propeptide was secreted, but the M4 metalloprotease domain was degraded. Consequently, this segment of the FTP domain promotes intramolecular processing of proAur while bestowing a chaperone function, but discourages processing within the FTP domain of proElastase, where activation must be co-ordinated with passage across a second membrane. We conclude that the FTP domain of proAur is adapted to facilitate a rapid autocatalytic activation mechanism, consistent with the role or proAur as initiator of the staphylococcal proteolytic cascade. [source]


    Different estrogen sensitivity of urogenital tissue from women with and without stress urinary incontinence,,

    NEUROUROLOGY AND URODYNAMICS, Issue 6 2009
    Lena Edwall
    Abstract Aims Oral hormone replacement therapy (HRT) based on estradiol-17, (E2), E2 esters or conjugated equine estrogens gives rise to huge amounts of circulating estrone (E1) as a result of the first liver pass. E1 is an estrogen (ER) receptor agonist but has also been reported to act as a partial E2 antagonist in vitro. Our aim was to investigate the influence of circulating estrogens on estrogen sensitivity of urogenital tissue collagen turnover in patients with stress urinary incontinence (SUI) and in urologically healthy women, with and without HRT, in view of possible effects of E1 as a partial E2 antagonist. Methods Markers of collagen turnover, the carboxy-terminal propeptide of type I procollagen (PICP), the carboxy-terminal telopeptide of type I collagen (ICTP) and the amino-terminal propeptide of procollagen III (PIIINP) were assayed in urogenital tissue homogenates and E1 and E2 were analyzed in serum from 54 patients with SUI and 29 urologically healthy women. Results In the total control group only a significant positive correlation was found between E2 and T-PICP. Lowering the upper serum E1 limit resulted in significant positive correlations also between E2 and T-PIIINP and finally also between E2 and T-ICTP. This pattern was found also in subgroups of post- and premenopausal controls. No association between serum E2 and collagen turnover markers and no effects of lowering the upper serum E1 limit was found in the total and postmenopausal SUI patients, while the correlation pattern in premenopausal SUI patients showed some resemblance to that in the controls. Conclusion At physiological E1 levels E2 increases collagen turnover in urogenital tissue in urologically healthy women but not in women with SUI in general; however, there was a certain effect of E2 in premenopausal but not in postmenopausal SUI patients. Urogenital tissue in SUI patients and in urologically healthy women may differ in estrogen sensitivty and in SUI patients this difference may be related to menopause. Circulating E1, which is present in huge amounts during oral HRT, may act as an estrogen receptor agonist as well as a partial E2 antagonist also in humans in vivo. Neurourol. Urodyn. 28:516,520, 2009. © 2009 Wiley-Liss, Inc. [source]


    Effects of dexamethasone on proliferation, chemotaxis, collagen I, and fibronectin-metabolism of human fetal lung fibroblasts

    PEDIATRIC PULMONOLOGY, Issue 1 2001
    R.E. Brenner MD
    Abstract Premature infants at risk for bronchopulmonary dysplasia (BPD) are often treated with dexamethasone (Dex), which has been shown to suppress inflammatory processes in the lung. To elucidate a possible direct influence on the fibroproliferative component of the disease, we studied the effects of Dex in therapeutic and supratherapeutic dosages (5,50 nmol/L) on proliferation, chemotaxis, procollagen I, and fibronectin metabolism of human fetal lung fibroblasts in vitro. Proliferation was inhibited by Dex in a dose-dependent manner. Chemotactic activity in response to conditioned medium of human fetal fibroblasts also showed a dose-dependent inhibition after pretreatment with Dex. The amount of procollagen I C-terminal propeptide and fibronectin per cell in the cell culturesupernatant was increased in the presence of Dex. Our results show that Dex does not uniformly suppress the fibroproliferative activity of human fetal lung fibroblasts, which may explain in part the unsatisfactory long-term effects of Dex treatment in BPD. Pediatr Pulmonol. 2001; 32:1,7. © 2001 Wiley-Liss, Inc. [source]


    The Comparative Analysis of Osmotins and Osmotin-Like PR-5 Proteins

    PLANT BIOLOGY, Issue 2 2003
    S. An, lovar
    Abstract: One of the ways that plants respond to biotic and/or abiotic stress factors is the accumulation of pathogenesis-related proteins of class 5 (PR-5), which are evolutionary conserved in the plant kingdom. Within the PR-5 family, a distinct subgroup of osmotin and closely related proteins has been characterized. In contrast to the extracellular forms of PR-5 proteins, osmotins presumably accumulate in the vacuole of the cell. They contain a C-terminal propeptide that is considered to be a determinant for vacuolar targeting. The comparison of the three-dimensional structure of tobacco PR-5 d with the sequences of some osmotins showed that the proteins consist of three conserved domains, with the acidic cleft between domains I and II. Besides the constitutive species and tissue-specific presence, the osmotins are also induced by several abiotic and biotic stresses. Among them, fungal infections can elicit osmotin gene expression, and most known proteins from the family have antifungal activity in in vitro assays. In agreement with the osmotin structure and data on the activity of similar proteins, a two-step mechanism, which involves reaction of osmotins with the fungal wall and the permeabilization of fungal membranes, is discussed. [source]


    Localization of a flavonoid biosynthetic polyphenol oxidase in vacuoles

    THE PLANT JOURNAL, Issue 2 2006
    Eiichiro Ono
    Summary Aureusidin synthase, a polyphenol oxidase (PPO), specifically catalyzes the oxidative formation of aurones from chalcones, which are plant flavonoids, and is responsible for the yellow coloration of snapdragon (Antirrhinum majus) flowers. All known PPOs have been found to be localized in plastids, whereas flavonoid biosynthesis is thought to take place in the cytoplasm [or on the cytoplasmic surface of the endoplasmic reticulum (ER)]. However, the primary structural characteristics of aureusidin synthase and some of its molecular properties argue against localization of the enzyme in plastids and the cytoplasm. In this study, the subcellular localization of the enzyme in petal cells of the yellow snapdragon was investigated. Sucrose-density gradient and differential centrifugation analyses suggested that the enzyme (the 39-kDa mature form) is not located in plastids or on the ER. Transient assays using a green fluorescent protein (GFP) chimera fused with the putative propeptide of the PPO precursor suggested that the enzyme was localized within the vacuole lumen. We also found that the necessary information for vacuolar targeting of the PPO was encoded within the 53-residue N-terminal sequence (NTPP), but not in the C-terminal sequence of the precursor. NTPP-mediated ER-to-Golgi trafficking to vacuoles was confirmed by means of the co-expression of an NTPP-GFP chimera with a dominant negative mutant of the Arabidopsis GTPase Sar1 or with a monomeric red fluorescent protein (mRFP)-fused Golgi marker (an H+ -translocating inorganic pyrophosphatase of Arabidopsis). We identified a sequence-specific vacuolar sorting determinant in the NTPP of the precursor. We have demonstrated the biosynthesis of a flavonoid skeleton in vacuoles. The findings of this metabolic compartmentation may provide a strategy for overcoming the biochemical instability of the precursor chalcones in the cytoplasm, thus leading to the efficient accumulation of aurones in the flower. [source]


    Expression, purification, and characterization of pro-phenoloxidase-activating serine protease from Spodoptera litura

    ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2009
    Naresh Arora
    Abstract One of the important trigger molecules for innate immunity is a serine protease that activates zymogen phenol oxidase (PPO). Central to wound healing response is the activation of phenol oxidase zymogen. Molecular characterization of phenol oxidase has been recently reported by us. Here, we report isolation, cloning, expression, and purification of prophenol oxidase activating enzyme 1 (slppae1) from polyphagous pest, Spodoptera litura. SLPPAE1 is induced within 6,h of physical injury. The structural features of the mature polypeptide are reminiscent of other lepidopteran PPAE in having a signal peptide, propeptide, and catalytically active polypeptide. The cDNA has been expressed in Sf21 cells using baculovirus expression vector. Fractionation of expressing Sf21 cells revealed its expression in the membranes. The recombinant protein was solubilized from membranes and purified by Ni-NTA affinity chromatography. The purified enzyme is catalytically active on chromogenic substrate, activates recombinantly expressed prophenol oxidase (PPO) of S. litura, and is sensitive to inhibition by aprotenin. N-terminal sequencing of processed phenol oxidase revealed 11,kDa propeptide instead of in-silico predicted 6,kDa polypeptide. © 2009 Wiley Periodicals, Inc. [source]


    Rapid and sustained improvement in bone and cartilage turnover markers with the anti,interleukin-6 receptor inhibitor tocilizumab plus methotrexate in rheumatoid arthritis patients with an inadequate response to methotrexate: Results from a substudy of the multicenter double-blind, placebo-controlled trial of tocilizumab in inadequate responders to methotrexate alone,

    ARTHRITIS & RHEUMATISM, Issue 1 2010
    Patrick Garnero
    Objective To investigate the effects of tocilizumab (TCZ) added to a stable dosage of methotrexate (MTX) on biochemical markers of bone and cartilage metabolism in patients in the multicenter double-blind, placebo-controlled OPTION (Tocilizumab Pivotal Trial in Methotrexate Inadequate Responders) study who have moderate-to-severe rheumatoid arthritis (RA) and an inadequate response to MTX. Methods Included in this study were 416 of the 623 patients with active RA enrolled in the OPTION study. Patients were randomized to receive TCZ (4 mg/kg or 8 mg/kg) or placebo intravenously every 4 weeks, with MTX continued at the stable prestudy doses (10,25 mg for 20 weeks, with a final followup at week 24). Serum biochemical markers of bone formation (osteocalcin, N-terminal propeptide of type I collagen [PINP]), bone resorption (C-terminal crosslinking telopeptide of type I collagen [CTX-I] and C-terminal crosslinking telopeptide of type I collagen generated by matrix metalloproteinases [ICTP]), cartilage metabolism (N-terminal propeptide of type IIA collagen [PIIANP]), collagen helical peptide [HELIX-II]), and matrix metalloproteinase 3 (MMP-3) were measured at baseline and at weeks 4, 16, and 24. Results TCZ induced marked dose-dependent reductions in PIIANP, HELIX-II, and MMP-3 levels at week 4 that were maintained until week 24, an effect associated with increased levels of bone formation markers that were significant as compared with placebo only for PINP and only at 4 weeks (P < 0.01 for both TCZ doses). TCZ induced significant decreases in the bone degradation markers CTX-I and ICTP, providing initial evidence of a beneficial effect on bone turnover. TCZ-treated patients who met the American College of Rheumatology 50% improvement criteria (achieved an ACR50 response) or achieved clinical remission (as determined by a Disease Activity Score in 28 joints <2.6) at week 24 had greater reductions in ICTP, HELIX-II, and MMP-3 levels as compared with ACR50 nonresponders. Conclusion TCZ combined with MTX reduces systemic bone resorption, cartilage turnover, and proteolytic enzyme MMP-3 levels, which provides evidence of a limitation of joint damage and possible beneficial effects on skeletal structure in patients with established moderate-to-severe RA. [source]