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Membrane Zone (membrane + zone)
Kinds of Membrane Zone Selected AbstractsHemidesmosome protein dynamics in live epithelial cellsCYTOSKELETON, Issue 2 2003Daisuke Tsuruta Abstract Hemidesmosomes mediate stable anchorage of epithelial cells to laminin-5 in the basement membrane zone and have been likened to spot-welds. Indeed, it has been assumed that hemidesmosomes are not dynamic, at least when compared to other matrix adhesion sites including focal contacts. We tested this notion by monitoring the fate of green fluorescent protein (GFP)-tagged human integrin ,4 subunit (GFP-h,4) and GFP-tagged 180-kD human bullous pemphigoid (BP) autoantigen (GFP-BP180) in live cultures of 804G cells that assemble numerous mature hemidesmosomes. In subconfluent 804G cells, both GFP-h,4 and GFP-BP180 protein clusters are not stable but assemble into and disassemble out of cat paw,like arrays at a relatively rapid rate. In confluent populations of 804G cells, although some cat paw,like clusters of both GFP-h,4 and GFP-BP180 are stable over periods of >60 min, other GFP-h,4 and GFP-BP180 protein arrays form and/or disappear during the same time period. Moreover, individual labeled particles show considerable motility in the plane of the membrane. Fluorescence recovery after photobleaching analyses provide a further indication of the dynamics of hemidesmosome proteins. In particular, bleached GFP-h,4 protein clusters in confluent cells recover signal within about 30 min, indicating that there is a relatively rapid turnover of hemidesmosome components in protein arrays clustered along the substratum attached surface of a cell. The rate of recovery is dependent on an intact microfilament system. In sharp contrast, bleached GFP-BP180 protein clusters in confluent cells fail to recover signal even when observed for longer than 60 min. To evaluate hemidesmosome protein dynamics in motile cells, we monitored GFP-h,4 and GFP-BP180 in 804G cells populating scrape wound sites in vitro. In these migratory cells, which lack mature hemidesmosomes, integrin ,4 subunit and BP180 protein clusters progressively assemble and disassemble into linear and cat-paw arrays. In summary, hemidesmosome protein clusters, like their counterparts in focal contacts, are dynamic. We discuss these results in relation to hemidesmosome functions. Cell Motil. Cytoskeleton 54:122,134, 2003. © 2003 Wiley-Liss, Inc. [source] Equine laminitis: glucose deprivation and MMP activation induce dermo-epidermal separation in vitroEQUINE VETERINARY JOURNAL, Issue 3 2004K. R. French Summary Reasons for performing study: Acute laminitis is characterised by hoof lamellar dermal-epidermal separation at the basement membrane (BM) zone. Hoof lamellar explants cultured in vitro can also be made to separate at the basement membrane zone and investigating how this occurs may give insight into the poorly understood pathophysiology of laminitis. Objectives: To investigate why glucose deprivation and metalloproteinase (MMP) activation in cultured lamellar explants leads to dermo-epidermal separation. Methods: Explants, cultured without glucose or with the MMP activator p -amino-phenol-mercuric acetate (APMA), were subjected to tension and processed for transmission electron microscopy (TEM). Results: Without glucose, or with APMA, explants under tension separated at the dermo-epidermal junction. This in vitro separation occurred via 2 different ultrastructural processes. Lack of glucose reduced hemidesmosomes (HDs) numbers until they disappeared and the basal cell cytoskeleton collapsed. Anchoring filaments (AFs), connecting the basal cell plasmalemma to the BM, were unaffected although they failed under tension. APMA activation of constituent lamellar MMPs did not affect HDs but caused AFs to disappear, also leading to dermo-epidermal separation under tension. Conclusions: Natural laminitis may occur in situations where glucose uptake by lamellar basal cells is compromised (e.g. equine Cushing's disease, obesity, hyperlipaemia, ischaemia and septicaemia) or when lamellar MMPs are activated (alimentary carbohydrate overload). Potential relevance: Therapies designed to facilitate peripheral glucose uptake and inhibit lamellar MMP activation may prevent or ameliorate laminitis. [source] Genkwanin up-regulates the transcriptional activation of human type vii collagen gene promoterINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2007N. Takebayashi In a recent study, stimulating the formation of anchoring fibrils at the basement membrane zone in skin contributed to preventing skin ageing, such as wrinkle formation. Expression of the type VII collagen gene induces the formation of anchoring fibrils composed mainly of collagen type VII. We therefore transiently transfected a keratinocyte cell line with the plasmids containing type VII collagen gene promoter located upstream of the luciferase gene. We investigated the promoter activity under the presence of flavonoids and we found that Genkwanin up-regulates the transcriptional activation of human type VII collagen gene promoter. [source] Pretibial epidermolysis bullosa: is this case a new subtype with loss of types IV and VII collagen?INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 8 2009Hong-sun Lee MD Pretibial epidermolysis bullosa (PEB) is an extremely rare subtype of dominant dystrophic epidermolysis bullosa (DDEB), in which recurrent blistering with scarring predominantly involves the pretibial skin. Nail dystrophy, albopapuloid lesions, and hypertrophic scars may also occur. In PEB, immunohistochemical and electron microscopic studies demonstrate the complete or partial loss of the anchoring fibril (AF) in the basement membrane zone, suggesting disturbed synthesis or excessive degradation of collagen VII, the main component of AF. Interestingly, we report a case of PEB with unusual results of joint loss of types IV and VII collagen. [source] An immunohistochemical study of laminin in basal cell carcinomaJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2010Wedad Z. Mostafa Background: Laminins are components of the extracellular matrix that mediate cell adhesion, growth, migration, proliferation and differentiation. Basement membrane (BM) laminins, in particular, may play a role in enhancing carcinoma cell motility. Aim: To evaluate the distribution pattern of laminin in basal cell carcinoma (BCC), as regards the basement membrane, cellular cytoplasm, peritumoral lacunae and surface epithelium and to correlate laminin distribution with different variants of BCC. Patients and Methods: Skin biopsy specimens were obtained from 21 BCC patients for routine histopathological and immunohistochemical study. Laminin was evaluated qualitatively and semiquantitatively using monoclonal mouse antihuman antibody (Dako-Laminin, 4C7. Code No: MO638, which reacts with the terminal globular domain of the ,5 chain) Results: The majority of BCC cases showed patchy cytoplasmic distribution of laminin. The BM expression of laminin, in most cases, was well defined, fine and linear with irregular areas of thickening. Staining intensity was moderate in differentiated and mixed variants, weak in superficial spreading and absent in morpheic types. Conclusion: Cytoplasmic and basement membrane laminin is important in the pathogenesis and invasion of BCC. Most laminin was in basement membrane zone (BMZ), and the more differentiated the tumor, the more cytoplasmic and BM staining it expressed. [source] Basement membrane changes in lichen planopilarisJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 11 2009K Al-Refu Abstract Background, Lichen planopilaris (LPP) is an inflammatory disease that affects the scalp and tends to produce cicatricial alopecia. The inflammatory process frequently results in the disruption of the basal cell of the external root sheath of the hair follicle. Objectives, To investigate the alterations in the basement membrane zone (BMZ) in LPP by immunohistochemistry. Methods, Skin biopsies from six patients with LPP plus six normal controls were studied by immunohistochemistry with antibodies to the following BMZ components: cytokeratin 5, cytokeratin 14, BP230 (bullous pemphigoid), BP180, plectin, laminin 5, collagen IV and collagen VII. Results, The localization and staining of the hemidesmosome, laminin and collagen components were strikingly different in the inflamed follicular epithelium when compared to the uninvolved follicles or interfollicular epithelium in active LPP lesions. The hemidesmosome-associated complexes were weakly expressed and discontinuous in involved hair follicles. The expression of laminin-5, type IV collagen and type VII collagen was disrupted and not linear along the BMZ with finger-like projections of the staining protruding into the dermis. The expression of the intermediate filaments was normal. Conclusion, These alterations in the BMZ in LPP may explain the abnormal healing at follicular level which leads to irreversible hair loss and scarring in this condition. [source] PL1 Subepithelial bullous diseases , topic overviewORAL DISEASES, Issue 2006M Mravak-Stipeti Subepithelial bullous diseases comprise the group of mucocutaneous autoimmune blistering diseases characterized by subepithelial separation and the deposition of immunoglobulin and complement against several antigens along the basement membrane zone (BMZ). This result in spectrum of diseases that affect skin, oral mucosa, and other mucosal membranes and include bullous pemphigoid (BP), mucous membrane (cicatricial) pemphigoid (MMP), linear IgA disease (LAD), and chronic bullous dermatosis of childhood (CBDC). The most common clinical features are oral erosions, desquamative gingivitis and conjunctival fibrosis, as well as skin lesions, predominantly in older female population. The heterogeneity of clinical presentation and diversity of target autoantigens have contributed to difficulties in characterizing this condition immunologically. In addition to the clinical presentation and a subepithelial vesicle or bullae on routine histologic analysis, the diagnosis is based on direct and indirect immunofluorescence studies. The nature of the disease is determined by the target antigens in the epithelium and BMZ such as antigen 180 (BP180), antigen 230 (BP230), laminin 5, and beta 4 integrin. Circulating IgG and IgA antibodies bind to different epitopes of BP180. The use of salt-split skin substrate enables differentiation between epidermal and dermal 'binders'. Since the antigen and the antibody titer appear to have direct relationships with the disease severity, and a combination of clinical finding and antibody titer provides valuable prognostic data, these investigations should be carried out routinely. Clinicians should recognize clinical spectrum of SBD, the histopathologic and immunopathologic characteristics, the differential diagnosis, the treatment, and the natural history of the disease. Involvement of oral medicine specialists, dermatologists, ophthalmologists, otolaryngologists and gastroenterologists contribute to early diagnosis and will aid in providing SBD patients with the highest quality of care. [source] Comparative Histology and Vibration of the Vocal Folds: Implications for Experimental Studies in Microlaryngeal Surgery ,THE LARYNGOSCOPE, Issue 5 2000C. Gaelyn Garrett MD Abstract Objectives/Hypothesis To determine the most suitable animal model for experimental studies on vocal fold surgery and function by a histological comparison of the microflap surgical plane and laryngeal videostroboscopy (LVS) in different species of animals. A second goal was to determine how the layered vocal fold structure in humans and three different animal species affects surgical dissection within the lamina propria. Study Design Prospective laboratory. Methods Three larynges each from dogs, monkeys, and pigs were compared with three ex vivo human larynges. Microflap surgery was performed on one vocal fold from each larynx. Both the operated and nonoperated vocal folds were examined histologically using stains specific for elastin, mature collagen, and ground substance. Based on the histological results, LVS was performed on two dogs and two pigs after first performing a tracheotomy for ventilation and airflow through the glottis. Arytenoid adduction sutures were placed to facilitate vocal fold adduction. Results The distributions of the collagen and elastin fibers were found to differ among the species with concentrations varying within species. Unlike the human vocal fold, which has a higher elastin concentration in the deeper layers of the lamina propria, both the pig and the dog had a thin band of elastin concentrated just deep to the basement membrane zone in the superficial layer. Just deep to this thin band, the collagen and the elastin were less concentrated. The monkey vocal fold had a very thin mucosal layer with less elastin throughout the mucosa. The microflap dissections in each of the dog, pig, and human vocal folds were similar, being located within that portion of the superficial lamina propria where the elastin and mature collagen are less concentrated. The microflap plane in the monkey vocal fold was more deeply located near the vocalis fibers. Despite the differences in elastin concentration, the microflap plane in both the dog and the pig was found to be similar to that in humans. The dog anatomy was much more suitable for microsuspension laryngoscopy and stroboscopic examination. The dog vocal folds vibrated in a similar fashion to human vocal folds with mucosal waves and vertical phase differences, features not seen in the pig vocal folds. Conclusions Based on both the histological and stroboscopic results, the dog was believed to be a more suitable animal model for studies on vocal fold surgery, acknowledging that no animal's laryngeal anatomy is identical to that of the human. The dog LVS model presented allows for longitudinal laryngeal studies requiring repeated examinations at multiple time periods with histological correlation applied at sacrifice. [source] Antiplectin autoantibodies in subepidermal blistering diseasesBRITISH JOURNAL OF DERMATOLOGY, Issue 4 2009J.J.A. Buijsrogge Summary Background, Hemidesmosomal proteins may become targets of autoimmunity in subepidermal blistering diseases. Well-known recognized autoantigens are the intracellular plaque protein BP230, the transmembrane BP180 and its shed ectodomain LAD-1. Objectives, To establish the prevalence of autoimmunity against plectin, another intracellular plaque protein, and to investigate its antigenic sites. Methods, Two hundred and eighty-two patients with subepidermal blistering diseases, investigated by routine immunoblot analysis for possible antiplectin antibodies, were included in the study. Epitope mapping was performed using recombinantly produced overlapping plectin domains from the actin-binding domain to the rod domain. The COOH-terminal region of plectin was not included in the study. Results, In 11 of 282 (3·9%) patients an immunoblot staining pattern identical to that of antiplectin monoclonal antibody HD121 was found. Affinity-purified antibodies bound back to normal human skin in a pattern typical for plectin, i.e. to the epidermal basement membrane zone as well as to keratinocytes in the epidermis, and to myocytes. No binding was seen to plectin-deficient skin of a patient with epidermolysis bullosa simplex with muscular dystrophy. Epitope mapping of the plectin molecule showed that the central coiled-coil rod domain is an immunodominant hotspot as 92% of the sera with antiplectin antibodies reacted with it. Most patients with antiplectin antibodies also had antibodies to other pemphigoid antigens. Conclusions, Plectin is a minor pemphigoid antigen with an immunodominant epitope located on the central rod domain. [source] U-serrated immunodeposition pattern differentiates type VII collagen targeting bullous diseases from other subepidermal bullous autoimmune diseasesBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004R.M. Vodegel Summary Background, Epidermolysis bullosa acquisita (EBA) can be differentiated from other subepidermal bullous diseases by sophisticated techniques such as immunoelectron microscopy, salt-split skin antigen mapping, fluorescence overlay antigen mapping, immunoblot and enzyme-linked immunosorbent assay. Objectives, To determine whether the diagnosis can also be made by routine direct immunofluorescence microscopy. Methods, We studied frozen skin biopsies from 157 patients with various subepidermal immunobullous diseases. Results, We found three distinct ,linear' fluorescence patterns at the basement membrane zone: true linear, n-serrated and u-serrated. The true linear pattern, often seen in conjunction with either the n- or the u-serrated pattern, was found in any subepidermal immunobullous disease with nongranular depositions. In bullous pemphigoid, mucous membrane pemphigoid, antiepiligrin cicatricial pemphigoid, p200 pemphigoid and linear IgA disease the n-serrated pattern was found, corresponding with depositions located in hemidesmosomes, lamina lucida or lamina densa. However, in EBA and bullous systemic lupus erythematosus the u-serrated staining pattern was seen, corresponding with the ultralocalization of type VII collagen in the sublamina densa zone. The diagnosis of EBA with IgG or IgA autoantibodies directed against type VII collagen was confirmed by immunoelectron microscopy, salt-split skin antigen mapping, fluorescence overlay antigen mapping or immunoblotting. Conclusions, Using this pattern recognition by direct immunofluorescence microscopy we discovered several cases of EBA which would otherwise have been erroneously diagnosed as a form of pemphigoid or linear IgA disease. [source] Linear IgA bullous dermatosis induced by interferon-, 2aCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 5 2009P. Kocyigit Summary Linear Ig A bullous dermatosis (LABD) is an acquired autoimmune subepidermal blistering disorder with linear deposits of IgA along the basement membrane zone. Its cause is unclear, although it appears to have an immune-mediated basis. Idiopathic, systemic disorder-related, and rarely drug-induced forms of LABD have been described. We describe a case of LABD associated with interferon-, 2A used for the treatment of Kaposi's sarcoma. [source] | ||||||||||