Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q16637 (SMA)
 8,107 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epithelial to mesenchymal transition (EMT) is a process occurring during embryonic development and cancer progression. Using recepteur d'origine nantais (RON)-expressing epithelial cells as a model, we showed that RON activation causes spindle-shaped morphology with increased cell motilities. These activities resemble those observed in EMT induced by transforming growth factor (TGF)-beta1 or by Ras-Raf signaling. By immunofluorescent and Western blot analyses, we found that constitutive RON expression results in diminished expression of E-cadherin, redistribution of beta-catenin, reorganization of actin cytoskeleton, and increased expression of vimentin, a mesenchymal filament. RON expression is also essential for TGF-beta1-induced expression of alpha-smooth muscle actin (alpha-SMA), a specialized mesenchymal marker. In the study of signaling pathways responsible for RON-mediated EMT, it was found that PD98059, a MAP kinase inhibitor, blocks the collaborative activities of RON and TGF-beta1 in induction of alpha-SMA expression and restores epithelial cells to their original morphology. Moreover, we showed that RON expression increases Smad2 gene promoter activities and protein expression, which significantly lowers TGF-beta1 threshold for EMT induction. These results suggest that persistent RON expression and activation cause the loss of epithelial phenotypes. These changes, collaborating with TGF-beta1 signaling, could play a critical role in epithelial transdifferentiation towards invasiveness and metastasis of certain cancers.
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PMID:Collaborative activities of macrophage-stimulating protein and transforming growth factor-beta1 in induction of epithelial to mesenchymal transition: roles of the RON receptor tyrosine kinase. 1500 85

Advanced glycation end products (AGEs) have been shown to play a role in tubular epithelial-myofibroblast transdifferentiation (TEMT) in diabetic nephropathy, but the intracellular signaling pathway remains unknown. We report here that AGEs signal through the receptor for AGEs (RAGE) to induce TEMT, as determined by de novo expression of a mesenchymal marker (alpha-smooth muscle actin, alpha-SMA) and loss of epithelial marker (E-cadherin), directly through the MEK1-ERK1/2 MAP kinase pathway, which is TGF-beta independent. This is supported by the following findings: AGEs induced de novo alpha-SMA mRNA expression as early as 2 hours followed by a loss of E-cadherin before TGF-beta mRNA expression at 24 hours and occurred in the absence of TGF-beta and AGE-induced activation of ERK1/2 MAP kinase at 15 minutes and TEMT at 24 hours were completely blocked by a neutralizing RAGE antibody, a soluble RAGE receptor, an ERK1/2 MAP kinase inhibitor (PD98059), and DN-MEK1, but not by a neutralizing TGF-beta antibody. Thus, this study demonstrates that AGEs activate the RAGE-ERK1/2 MAP kinase pathway to mediate the early TEMT process. The findings from this study suggest that targeting the RAGE or the ERK MAP kinase pathway may provide new therapeutic strategies for diabetic nephropathy and shed new light on the pathogenesis of diabetic nephropathy.
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PMID:Advanced glycation end products induce tubular epithelial-myofibroblast transition through the RAGE-ERK1/2 MAP kinase signaling pathway. 1503 26

The aim of this study was to investigate whether transforming growth factor-beta1 (TGF-beta1) could induce alveolar epithelial to mesenchymal transition (EMT) in vitro. Alveolar epithelial cells (AECs) from SD rats were isolated by elastase cell dispersion and IgG panning. Expression of alpha-smooth muscle actin (alpha-SMA) was assayed using Western blotting and immunostaining analysis. Morphological changes, the markers of epithelial cell (E-cadherin), and stress fiber by actin reorganization were detected by an indirect immunostaining. The contents of collagen I were determined by spectrophotometry. The levels of endogenous TGF-beta1 were measured with ELISA. Incubation of AECs with TGF-beta1 (0.1 approximately 10 ng/mL) induced abundant expression of alpha-SMA protein, and alpha-SMA expression in AECs reached a plateau when TGF-beta1 was > 3 ng/mL. Furthermore, we found that TGF-beta1 (3 ng/mL) exposure of AECs induced an authentic EMT characterized by abundant expression of alpha-smooth muscle actin, transformation of myofibroblastic morphology, increased formation of stress fiber by actin reorganization, and loss of epithelial marker E-cadherin. Meanwhile, significant increase in the levels of collagen I from 32.0 +/- 6.6 mg/g in control to 98 +/- 10.8 mg/g in TGF-beta1-treated group was found over a 72 h incubation period. Moreover, following stimulated by TGF-beta1 (3 ng/mL), a marked and time-dependent increase in endogenous TGF-beta1 released from AECs was observed. At time points 72 h, TGF-beta1 release mounted to 3451 pg/ml, which was much enough to induce EMT in vitro. These results demonstrated that AECs, under stimulation of TGF-beta1, underwent a conversion process into myofibroblasts in vitro.
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PMID:TGF-beta1 induces alveolar epithelial to mesenchymal transition in vitro. 2460 69

Epithelial-to-mesenchymal transition (EMT) and oxidative stress contribute to kidney tissue fibrosis in various forms of native kidney disease. However, their role in chronic allograft nephropathy (CAN) remains somewhat uncertain. To address this question, kidney transplants were performed in 3-month-old rats, using the Fisher 344 --> Lewis model of CAN. Six-month posttransplant, kidney allografts displayed significant tubular atrophy, interstitial fibrosis and vascular wall thickening. Allograft recipients had significantly higher levels of serum creatinine (4.7 +/- 1.3 versus 0.59 +/- 0.08 mg/dL, p = 0.03) and proteinuria (380 +/- 102 versus 30.2 +/- 8 mg/dL, p = 0.04) compared to syngeneic grafts. Semiquantitative PCR, immunoblot and immunohistochemical analyses demonstrated increased alpha-smooth muscle actin (alpha-SMA) mRNA and protein levels coupled with reduced E-cadherin mRNA and protein immunoreactivity, confirming the presence of CAN-associated EMT. Allograft alpha-SMA levels were increased as early as 1-2 weeks posttransplant. Immunohistochemical studies for collagen type I and III, superoxide anion (O(2) (-)), inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) confirmed that tubular O(2) (-), eNOS and iNOS, and interstitial collagen I, III and O(2) (-) levels were significantly increased in CAN-associated EMT. In conclusion, these observations suggest that CAN-associated EMT may be a link between oxidative stress and allograft fibrosis.
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PMID:Epithelial-to-mesenchymal transition and oxidative stress in chronic allograft nephropathy. 1570 4

The preservation of the peritoneal membrane is crucial for long-term survival in peritoneal dialysis. Epithelial-to-mesenchymal transition (EMT) is a process demonstrated in mesothelial cells (MC), responsible for negative peritoneal changes and directly related to PD. EMT enables neovascularization and fibrogenic capabilities in MC. Vascular endothelial growth factor (VEGF) is the mediator for neo-vascularization. Rapamycin is a potent immunosuppressor with antifibrotic action in renal allografts and has a demonstrated anti-VEGF effect. We performed this study with the hypothesis that rapamycin may regulate the EMT of MC. MC from human omentum were cultured. When mesothelial cells reached confluence, some of them were stimulated with r-TGF-beta (1 ng/mL) to induce EMT, co-administered with rapamycin (0.2, 2, 4, 20 and 40 nM). Other groups of cells received similar doses of rapamycin or r-TGF-beta, separately. Cells were analyzed at 6, 24, 48 hours and 7 days. As markers of EMT we included alfa -SMA, E-cadherin and snail nuclear factor by quantitative RT-PCR. EMT markers and regulators demonstrated the following changes with rapamycin: E-cadherin (a protective gene for EMT) increased 2.5-fold relative to controls under 40 nM, at 24h. Importantly, rapamycin inhibited snail expression induced by TGF-beta at 6h, whereas TGF-beta increased snail 10-fold. At day 7, rapamycin showed no anti-EMT properties. An important decrease in alfa -SMA expression by MC after rapamycin addition was observed. In conclusion, rapamycin shows a mild protective effect on EMT, as it increases E-cadherin and decreases alfa -SMA expression. Consequently, rapamycin might partially regulate the epithelial-to-mesenchymal transition of mesothelial cells.
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PMID:Effects of rapamycin on the epithelial-to-mesenchymal transition of human peritoneal mesothelial cells. 1577 May 93

Two alveolar epithelial cell lines R3/1 and L2 were screened by immunocytochemical and RT-PCR analysis of epithelial and mesenchymal/contractile marker proteins. R3/1 and L2 cells were tested for their sensitivity to bleomycin (BLM), an anticancer drug, which is proposed to induce changes in lung cell differentiation. Both epithelial cell lines exhibited a mixed phenotype consisting of epithelial (E-cadherin, aquaporin-5 and cytokeratin 8) and myofibroblast-like (vimentin, alpha-SMA and caveolin-3) properties suggesting that the cell lines are arrested in vitro at a certain developmental stage during epithelial-mesenchymal transition (EMT). BLM treatment of R3/1 cells resulted in a partial reversal of this process modifying the cells in an epithelial direction, e.g., upregulation of E-cadherin, aquaporin-5 and other lung epithelial antigens at the mRNA and protein level. L2 cells showed similar alterations following BLM exposure.Immunohistochemical investigation of lung tissue from two different animal models of BLM-induced fibrosis (mouse and rat), revealed no signs of EMT, e.g., myofibroblastic differentiation of alveolar epithelial cells in situ. Immunohistological analysis of tissue samples of the rat model showed a heterogeneous population of myofibroblasts (alpha-SMA+/caveolin-3+, alpha-SMA-/caveolin-3+, and alpha-SMA+/caveolin-3-). These results suggest that BLM, on one hand, induces fibrosis and on the other hand possibly suppresses EMT during fibrogenesis.
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PMID:Epithelial vs myofibroblast differentiation in immortal rat lung cell lines--modulating effects of bleomycin. 1618 68

In chronic renal diseases, progressive loss of renal function correlates with advancing tubulo-interstitial fibrosis. TGFbeta1-Smad (transforming growth factor-beta1-Sma and Mad protein) signalling plays an important role in the development of renal tubulo-interstitial fibrosis. Secretion of CTGF (connective-tissue growth factor; CCN2) by PTECs (proximal-tubule epithelial cells) and EMT (epithelial-mesenchymal transdifferentiation) of PTECs to myofibroblasts in response to TGFbeta are critical Smad-dependent events in the development of tubulo-interstitial fibrosis. In the present study we have investigated the distinct contributions of Smad2 and Smad3 to expression of CTGF, E-cadherin, alpha-SMA (alpha-smooth-muscle actin) and MMP-2 (matrix-metalloproteinase-2) in response to TGFbeta1 treatment in an in vitro culture model of HKC-8 (transformed human PTECs). RNA interference was used to achieve selective and specific knockdown of Smad2 and Smad3. Cellular E-cadherin, alpha-SMA as well as secreted CTGF and MMP-2 were assessed by Western immunoblotting. TGFbeta1 treatment induced a fibrotic phenotype with increased expression of CTGF, MMP-2 and alpha-SMA, and decreased expression of E-cadherin. TGFbeta1-induced increases in CTGF and decreases in E-cadherin expression were Smad3-dependent, whereas increases in MMP-2 expression were Smad2-dependent. Increases in alpha-SMA expression were dependent on both Smad2 and Smad3 and were abolished by combined knockdown of both Smad2 and Smad3. In conclusion, we have demonstrated distinct roles for Smad2 and Smad3 in TGFbeta1-induced CTGF expression and markers of EMT in human PTECs. This can be of therapeutic value in designing targeted anti-fibrotic therapies for tubulo-interstitial fibrosis.
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PMID:The differential role of Smad2 and Smad3 in the regulation of pro-fibrotic TGFbeta1 responses in human proximal-tubule epithelial cells. 1625 18

The aim of this study was to assess the morphological characteristics and immunohistochemical profile of breast carcinomas with basal and myoepithelial phenotypes to obtain a better understanding of their biological behaviour and nature. One thousand nine hundred and forty-four invasive breast carcinomas were examined, using tissue microarray (TMA) technology and immunohistochemistry, to identify those tumours that showed basal and myoepithelial phenotypes, and their immunophenotype profile was characterized using a variety of markers. In addition, haematoxylin and eosin-stained sections of these tumours were studied for several morphological parameters. The findings were correlated with patient and tumour characteristics and outcome data. Tumours were classified into two groups: (1) tumours with basal phenotype [expressing one or both basal markers (CK5/6 and/or CK14)] and (2) tumours with myoepithelial phenotype (expressing SMA and/or p63). Group 1 was further subdivided into two subgroups: (A) dominant basal pattern (more than 50% of cells positive) and (B) basal characteristics (10-50% of cells positive). Group 1 tumours constituted 18.6% (8.6% and 10% for groups 1A and 1B, respectively) and group 2 constituted 13.7% of the cases. In both groups, the most common histological types were ductal/no specific type, tubular mixed and medullary-like carcinomas; the majority of these tumours were grade 3. There were positive associations with adenoid cystic growth pattern, loss of tubule formation, marked cellular pleomorphism, poorer Nottingham prognostic index, and development of distant metastasis. In addition, associations were found with loss of expression of steroid hormone receptors and FHIT proteins and positive expression of p53 and EGFR. The most common characteristics in group 1 were larger size, high-grade comedo-type necrosis, development of tumour recurrence, and absence of lymph node disease. Group 2 tumours were more common in younger patients and were associated with central acellular zones, basaloid change, and positive E-cadherin protein expression. Group 1 characteristics were associated with both reduced overall survival (OS) [log rank (LR) = 22.5, p < 0.001] and reduced disease-free interval (DFI) (LR = 30.1, p < 0.001), while group 2 characteristics showed an association with OS (LR = 5, p = 0.02) but not with DFI. Multivariate analysis showed that basal, but not myoepithelial, phenotype has an independent value in predicting outcome. Breast cancers with basal and myoepithelial phenotypes are distinct groups of tumours that share some common morphological features and an association with poor prognosis. The basal rather than the myoepithelial phenotype has the strongest relationship with patient outcome.
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PMID:Morphological and immunophenotypic analysis of breast carcinomas with basal and myoepithelial differentiation. 1642 94

Pericryptal myofibroblast growth in descending colonic crypts correlates with the activation of the renin-angiotensin-aldosterone system. Earlier work showed that during the transition from a high-Na(+) (HS) to low-Na(+) (LS) diet there are changes in the colonic crypt wall and pericryptal sheath. As LS diet increases both aldosterone and angiotensin II, the aim here was to determine their individual contributions to the trophic changes in colonic crypts. Experiments were conducted on control and adrenalectomized Sprague-Dawley rats fed an HS diet and then switched to LS diet for 3 days and supplemented with aldosterone or angiotensin II. The actions of the angiotensin-converting enzyme inhibitor captopril, the angiotensin receptor antagonist losartan and the aldosterone antagonist spironolactone on extracellular matrix proteins, claudin 4 and E-cadherin myofibroblast proteins, alpha-smooth muscle actin (alpha-SMA) and OB-cadherin (cadherin 11), angiotensin type 1 and TGFbetar1 membrane receptors were determined by immunolocalization in fixed distal colonic mucosa. The LS diet or aldosterone supplementation following ADX in HS or LS increased extracellular matrix, membrane receptors and myofibroblast proteins, but angiotensin alone had no trophic effect on alpha-SMA. These results show that aldosterone stimulates myofibroblast growth in the distal colon independently of dietary Na(+) intake and of angiotensin levels. This stimulus could be a genomic response or secondary to stretch of the pericryptal sheath myofibroblasts accompanying enhanced rates of crypt fluid absorption.
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PMID:Pericryptal myofibroblast growth in rat descending colon induced by low-sodium diets is mediated by aldosterone and not by angiotensin II. 1644 Jan 81

Immunohistochemistry is widely used for pathological diagnosis of breast lesions. Other than hormone receptors and HER2/neu analysis for primary breast carcinomas, several markers may be useful for differential diagnoses, although in limited situations. To decide the malignant potential of intraductal proliferative lesions, analysis for the staining pattern of cytokeratins may be a good reference. Most ductal carcinoma in situ cases are diffusely positive for luminal cell markers (CK8, CK18, CK19), but negative for basal cell markers (CK5/6 and CK14). However, usual ductal hyperplasia may show the mosaic staining patterns for any of these markers, which may indicate a heterogeneous cell population in benign lesions. Myoepithelial markers (alpha-SMA, myosin, calponin, p63, CD10) are almost consistently positive for benign papillomas but they do not completely distinguish intraductal papillary carcinomas. Preservation of myoepithelial layer is the diagnostic key when looking at benign sclerosing lesions, including carcinoma with pseudoinvasive structures. E-cadherin is mostly positive for ductal carcinomas but negative for lobular carcinomas. Some of the lobular carcinomas are positive for 34betaE12, but they are consistently negative for CK5/6. Comparison with histopathological findings of hematoxylin and eosin is essential to make proper diagnosis in the individual case.
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PMID:New trends of immunohistochemistry for making differential diagnosis of breast lesions. 1657 8


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