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Secreted Form (secreted + form)
Selected AbstractsFGF19-FGFR4 signaling elaborates lens induction with the FGF8-L-Maf cascade in the chick embryoDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 4 2005Hitomi Kurose The fibroblast growth factor (FGF) family is known to be involved in vertebrate eye development. However, distinct roles of individual FGF members during eye development remain largely elusive. Here, we show a detailed expression pattern of Fgf19 in chick lens development. Fgf19 expression initiated in the forebrain, and then became restricted to the distal portion of the optic vesicle abutting the future lens placode, where FGF receptor 4 (Fgfr4), a receptor for FGF19, was expressed. Fgf8, a positive regulator for L-Maf, was expressed in a portion of the optic vesicle. To examine the role of FGF19 signaling during early eye development, Fgf19 was misexpressed near the presumptive lens ectoderm; however, no alteration in the expression of lens marker genes was observed. Conversely, a secreted form of FGFR4 was misexpressed to inhibit an FGF19 signal, resulting in the induction of L-Maf expression. To further define the relationship between L-Maf and Fgf19, L-Maf misexpression was performed, resulting in ectopic induction of Fgf19 expression by Hamburger and Hamilton's stage 12/13. Furthermore, misexpression of Fgf8 induced Fgf19 expression in addition to L-Maf. These results suggest that FGF19-FGFR4 signaling plays a role in early lens development in collaboration with FGF8 signaling and L-Maf transcriptional system. [source] Misfolded transthyretin causes behavioral changes in a Drosophila model for transthyretin-associated amyloidosisEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Malgorzata Pokrzywa Abstract Familial amyloidotic polyneuropathy is an autosomal dominant neurodegenerative disorder caused by accumulation of mutated transthyretin (TTR) amyloid fibrils in different organs and prevalently around peripheral nerves. We have constructed transgenic flies, expressing the clinical amyloidogenic variant TTRL55P and the engineered variant TTR-A (TTRV14N/V16E) as well as the wild-type protein, all in secreted form. Within a few weeks, both mutants but not the wild-type TTR demonstrated a time-dependent aggregation of misfolded molecules. This was associated with neurodegeneration, change in wing posture, attenuation of locomotor activity including compromised flying ability and shortened life span. In contrast, expression of wild-type TTR had no discernible effect on either longevity or behavior. These results suggest that Drosophila can be used as a disease-model to study TTR amyloid formation, and to screen for pharmacological agents and modifying genes. [source] Modulation of angiogenesis is effective in a model of rheumatoid arthritisJOURNAL OF ANATOMY, Issue 5 2002A. O. Afuwape A feature of rheumatoid arthritis (RA) is prominent hyperplasia of the synovium, which results in an increased distance between the invasive pannus and the existing synovial vasculature. Concomitantly the hyperplastic tissue imposes an augmented metabolic demand on the pre-existing vasculature. As a consequence the synovium in RA becomes hypoxic, resulting in an increased rate of formation of new blood vessels, to supply nutrients and oxygen. Targeting the vasculature in RA is a potential therapeutic approach in RA. VEGF, a key vascular permeability and angiogenic factor, is expressed in RA. In this study we utilised adenovirus expressing the secreted form of the extracellular domain of the Flt-1 VEGF receptor (sFlt-1) to inhibit VEGF in the collagen-induced arthritis (CIA) model, to determine whether blocking the effects of vegf might be an effective treatment for RA. AdvsFlt-1, administered intravenously on the first day of arthritis, significantly suppressed CIA. For example, on d 6 of arthritis the mean increase in paw thickness, which reflects oedema, for untreated and null adenovirus-treated animals was 0.23 ± 0.05 mm and 0.38 ± 0.08, respectively, compared to 0.07 ± 0.05 for AdvsFlt-1-treated mice (P < 0.001 vs. Adv0-treated and untreated mice by 2-way anova). Western blot analyses revealed the presence of a 100-kDa band, corresponding to human sFlt-1, in liver extracts from arthritic mice infected with AdvsFlt-1 at 24 h but not 72 h after infection. This band was absent in liver extracts from Adv0-infected mice and all synovial extracts. Measurement of protein levels by ELISA demonstrated the presence of sFlt-1 in liver, synovium and serum, although levels declined by 72 h post infection. These data suggest efficient but transient expression of sFlt-1. Sera from adenovirus infected mice were found to contain antiviral antibodies and additionally, sera from AdvsFlt-1-infected but not Adv0-infected mice recognised human recombinant sFlt-1. These observations demonstrate that adenoviral mediated delivery of human sFlt-1 leads to transient gene expression and suppression of CIA. This effect is reduced later in the course of disease due to the expression of antiadenovirus as well as antisFlt-1 antibodies. Future studies will assess the effect of combination treatment, using AdvsFlt-1 together with anti-TNF(antibody, to prolong the beneficial effects of VEGF blockade. These results suggest that blocking the pro-angiogenic and permeability action of VEGF may be beneficial for treatment of RA. [source] BMP-9-induced osteogenic differentiation of mesenchymal progenitors requires functional canonical Wnt/,-catenin signallingJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009Ni Tang Abstract Bone morphogenetic protein 9 (BMP-9) is a member of the transforming growth factor (TGF)-,/BMP superfamily, and we have demonstrated that it is one of the most potent BMPs to induce osteoblast differentiation of mesenchymal stem cells (MSCs). Here, we sought to investigate if canonical Wnt/,-catenin signalling plays an important role in BMP-9-induced osteogenic differentiation of MSCs. Wnt3A and BMP-9 enhanced each other's ability to induce alkaline phosphatase (ALP) in MSCs and mouse embryonic fibroblasts (MEFs). Wnt antagonist FrzB was shown to inhibit BMP-9-induced ALP activity more effectively than Dkk1, whereas a secreted form of LPR-5 or low-density lipoprotein receptor-related protein (LRP)-6 exerted no inhibitory effect on BMP-9-induced ALP activity. ,-Catenin knockdown in MSCs and MEFs diminished BMP-9-induced ALP activity, and led to a decrease in BMP-9-induced osteocalcin reporter activity and BMP-9-induced expression of late osteogenic markers. Furthermore, ,-catenin knockdown or FrzB overexpression inhibited BMP-9-induced mineralization in vitro and ectopic bone formation in vivo, resulting in immature osteogenesis and the formation of chondrogenic matrix. Chromatin immunoprecipitation (ChIP) analysis indicated that BMP-9 induced recruitment of both Runx2 and ,-catenin to the osteocalcin promoter. Thus, we have demonstrated that canonical Wnt signalling, possibly through interactions between ,-catenin and Runx2, plays an important role in BMP-9-induced osteogenic differentiation of MSCs. [source] Developmental and adult expression of semaphorin 2a in the cricket Gryllus bimaculatus,THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2007Kristen R. Maynard Abstract Developmental guidance cues act to direct growth cones to their correct targets in the nervous system. Recent experiments also demonstrate that developmental cues are expressed in the adult mammalian nervous system, although their function in the brain is not yet clear. The semaphorin gene family has been implicated in the growth of dendrites and axons in a number of different species. While the expression of semaphorin and its influence on tibial pioneer neurons in the developing limb bud have been well characterized in the grasshopper, the expression of semaphorin 2a (sema2a) has not been explored in the adult insect. In this study we used polymerase chain reaction (PCR) with degenerate and gene-specific primers to clone part of the secreted form of sema2a from Gryllus bimaculatus. Using in situ hybridization and immunohistochemistry, we confirmed that sema2a mRNA and protein expression patterns in the embryonic cricket were similar to that seen in the grasshopper. We also showed that tibial neuron development in crickets was comparable to that described in grasshopper. An examination of both developing and adult cricket brains showed that sema2a mRNA and protein were expressed in the Kenyon cells in mushroom bodies, an area involved in learning and memory. Sema2a expression was most obvious near the apex of the mushroom body in a region surrounding the neurogenic tip, which produces neurons throughout the life of the cricket. We discuss the role of neurogenesis in learning and memory and the potential involvement of semaphorin in this process. J. Comp. Neurol. 503:169,181, 2007. © 2007 Wiley-Liss, Inc. [source] Inefficient processing of mRNA for the membraneform of IgE is a genetic mechanism to limit recruitment of IgE-secreting cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2006Alexander Karnowski Abstract Immunoglobulin,E (IgE) is the key effector element in allergic diseases ranging from innocuous hay fever to life-threatening anaphylactic shock. Compared to other Ig classes, IgE serum levels are very low. In its membrane-bound form (mIgE), IgE behaves as a classical antigen receptor on B,lymphocytes. Expression of mIgE is essential for subsequent recruitment of IgE-secreting cells. We show that in activated, mIgE-bearing B,cells, mRNA for the membrane forms of both murine and human epsilon (,) heavy chains (HC) are poorly expressed compared to mRNA for the secreted forms. In contrast, in mIgG-bearing B,cells, mRNA for the membrane forms of murine gamma-1 (,1) and the corresponding human ,4 HC are expressed at a much higher level than mRNA for the respective secreted forms. We show that these findings correlate with the presence of deviant polyadenylation signal hexamers in the 3,,untranslated region (UTR) of both murine and human ,,genes, causing inefficient processing of primary transcripts and thus poor expression of the proteins and poor recruitment of IgE-producing cells in the immune response. Thus, we have identified a genetic steering mechanism in the regulation of IgE synthesis that represents a further means to restrain potentially dangerous, high serum IgE levels. [source] Alternative splicing generates a family of putative secreted and membrane-associated MUC4 mucinsFEBS JOURNAL, Issue 14 2000Nicolas Moniaux The MUC4 mucin gene encodes a putative membrane-anchored mucin with predicted size of 930 kDa, for its 26.5-kb allele. It is composed of two regions, the 850-kDa mucin-type subunit MUC4, and the 80-kDa membrane-associated subunit MUC4,. In this study, we cloned and characterized unique MUC4 cDNA sequences that differ from the originally published sequence. Eight alternative splice events located downstream of the central large tandem repeat array generated eight new, distinct cDNAs. The deduced sequences of these MUC4 cDNAs (sv1- MUC4 to sv8- MUC4, the full length cDNA being called sv0- MUC4) provided seven distinct variants, five secreted forms and two membrane-associated forms. Furthermore, two other alternative splicing events located on both sides of the tandem repeat array created two variants, MUC4/Y and MUC4/X, both lacking the central tandem repeat. Therefore, MUC4 can be expressed in three distinct forms, one membrane-bound, one secreted, and one lacking the hallmark feature of mucin, the tandem repeat array. Although no specific function has yet been discovered for the family of proteins putatively produced from the unique MUC4 gene, we suspect that the MUC4 proteins may be implicated in the integrity and renewal of the epithelium. [source] | |||||||||||||