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Smooth Muscle Actin Expression (smooth + muscle_actin_expression)
Selected AbstractsCCR2 promotes hepatic fibrosis in mice,HEPATOLOGY, Issue 1 2009Ekihiro Seki Chemokines and chemokine receptors contribute to the migration of hepatic stellate cells (HSCs) and Kupffer cells, two key cell types in fibrogenesis. Here, we investigate the role of CCR2, the receptor for monocyte chemoattractant protein (MCP)-1, MCP-2, and MCP-3, in hepatic fibrosis. Hepatic CCR2, MCP-1, MCP-2, and MCP-3 messenger RNA expression was increased after bile duct ligation (BDL). Both Kupffer cells and HSCs, but not hepatocytes, expressed CCR2. BDL- and CCl4 -induced fibrosis was markedly reduced in CCR2,/, mice as assessed through collagen deposition, ,-smooth muscle actin expression, and hepatic hydroxyproline content. We generated CCR2 chimeric mice by the combination of clodronate, irradiation, and bone marrow (BM) transplantation allowing full reconstitution of Kupffer cells, but not HSCs, with BM cells. Chimeric mice containing wild-type BM displayed increased macrophage recruitment, whereas chimeric mice containing CCR2,/, BM showed less macrophage recruitment at 5 days after BDL. Although CCR2 expressed in the BM enhanced macrophage recruitment in early phases of injury, CCR2 expression on resident liver cells including HSCs, but not on the BM, was required for fibrogenic responses in chronic fibrosis models. In vitro experiments demonstrated that HSCs deficient in CCR2,/, or its downstream mediator p47phox,/, did not display extracellular signal-regulated kinase and AKT phosphorylation, chemotaxis, or reactive oxygen species production in response to MCP-1, MCP-2, and MCP-3. Conclusion: Our results indicate that CCR2 promotes HSC chemotaxis and the development of hepatic fibrosis. (HEPATOLOGY 2009.) [source] Hobnail hemangiomas (targetoid hemosiderotic hemangiomas) are true lymphangiomasJOURNAL OF CUTANEOUS PATHOLOGY, Issue 5 2004Folker E. Franke Background:, Hobnail hemangioma (targetoid hemosiderotic hemangioma) is a small benign vascular tumor of the superficial and mid-dermis. In contrast to its well-characterized histology, it has been unclear whether this tumor arises from blood vessel endothelial cells (BECs) or lymphatic vessel endothelial cells (LECs). Methods:, We analyzed 10 hobnail hemangiomas by immunohistochemistry, using the recently described lymphatic endothelial cell marker, D2-40. For comparison, CD31, CD34, and ,-smooth muscle actin expression were studied in consecutive sections of the paraffin-embedded tissues. Results:, In all analyzed vessels, D2-40 labeled exclusively LECs, whereas BECs were consistently negative. In contrast to capillary BECs, either neighboring the tumors or intermingled, neoplastic endothelial cells of all 10 hobnail hemangiomas were strongly labeled by D2-40. Conclusions:, The results suggest a lymphatic origin for hobnail hemangiomas. This view is further supported by the CD34 negativity of endothelial cells and the lack of actin-labeled pericytes in hobnail hemangiomas, both characteristic of lymphatic vessels. Moreover, our analysis revealed that microshunts between neoplastic lymphatic vascular channels and small blood vessels occur, explaining some features of hobnail hemangiomas, such as aneurysmatic microstructures, erythrocytes within and beneath neoplastic vascular spaces, inflammatory changes, scarring, and interstitial hemosiderin deposits. [source] Alcohol Primes the Airway for Increased Interleukin-13 SignalingALCOHOLISM, Issue 3 2009Patrick O. Mitchell Background:, Using an experimental model of airway fibrosis following lung transplantation, we recently showed that chronic alcohol ingestion by donor rats amplifies airway fibrosis in the recipient. Associated with alcohol-mediated amplification of airway fibrosis is increased transforming growth factor ,-1(TGF,1) and ,-smooth muscle actin expression. Other studies have shown that interleukin-13 (IL-13) modulates TGF,1 signaling during experimentally-induced airway fibrosis. Therefore, we hypothesized that IL-13 is a component of alcohol-mediated amplification of pro-fibrotic mediators in the alcoholic lung. Methods:, To test this hypothesis, we analyzed tracheal epithelial cells and type II alveolar cells from control- or alcohol-fed rats, alcohol-treated mouse lung fibroblasts, and human bronchial epithelial cells in vitro for expression of various components of the IL-13 signaling pathway. Signaling via the IL-13 pathway was assessed by measuring levels of phosphorylated signal transducers and activators of transcription-6 (STAT6). In addition, we performed heterotopic tracheal transplantation using control-fed and alcohol-fed donor rats and analyzed tracheal allografts for expression of components of the IL-13 signaling pathway by RT-PCR and immunocytochemical analyses. Results:, Interleukin-13 expression was detected in type II alveolar epithelial cells and human bronchial epithelial cells, but not in lung fibroblasts. IL-13 expression was decreased in whole lung and type II cells in response to alcohol exposure. In all cell types analyzed, expression of IL-13 signaling receptor (IL-13R,1) mRNA was markedly increased. In contrast, mRNA and protein expression of the IL-13 decoy receptor (IL-13R,2) were decreased in all cells analyzed. Exposure to alcohol also increased STAT6 phosphorylation in response to IL-13 and lipopolysaccharide. Conclusions:, Data from multiple cell types in the pulmonary system suggest that IL-13 and its receptors play a role in alcohol-mediated activation of pro-fibrotic pathways. Taken together, these data suggest that alcohol primes the airway for increased IL-13 signaling and subsequent tissue remodeling upon injury such as transplantation. [source] Effects of interleukin 18 on injury and activation of human proximal tubular epithelial cellsNEPHROLOGY, Issue 1 2007DONG LIANG SUMMARY: Background/Aims: Injury and activation of tubular proximal epithelial cells (TEC) play central roles in renal tubulointerstitial fibrosis (TIF), but its mechanisms remain obscure. Interleukin 18 (IL-18) is overproduced during chronic kidney diseases (CKD), but how IL-18 affects the biological behaviour of TEC is not clear. The aim of the present study is to reveal the role of IL-18 in renal TIF. Methods: The expressions of IL-18 and IL-18 receptor in TEC were detected by immunohistochemical staining in vivo and by reverse transcriptase polymerase chain reaction (RT-PCR) in vitro. TEC line (HK-2 cells) were incubated without or with IL-18. Cell proliferation and cell cycle were evaluated by methyl thiazolyl tetrazolium assay and flow cytometric analysis, respectively. Cell apoptosis was assessed by Hoechst 33258 staining. Expression of ,-smooth muscle actin was evaluated by RT-PCR, immunocytochemical staining and flow cytometric analysis, respectively. Type I collagen, fibronectin, MCP-1 and RANTES in cultured supernatants were measured by enzyme-linked immunosorbent assay. Results: IL-18 expression in TEC increased significantly in CKD state. IL-18 receptor was constitutively expressed in normal proximal TEC, and its expression increased strongly in CKD state. Proliferation and cell cycle of HK-2 cells were not affected by IL-18. Cell apoptosis, ,-smooth muscle actin expression, type I collagen and fibronectin production as well as MCP-1 secretion were promoted by IL-18 in dosage- and/or time-dependent manners, but RANTES secretion was not affected. Conclusion: IL-18 may play a crucial role in the process of TIF by promoting TEC injury and activation, and could be a target of the therapeutic approaches against TIF. [source] Upregulation of heparin-binding epidermal growth factor-like growth factor and osteopontin in experimental hydronephrosisNEPHROLOGY, Issue 3 2000M Katerelos SUMMARY This study examined the expression of heparin-binding epidermal growth factor-like growth factor (HB-EGF) and osteopontin in unilateral ureteral obstruction (UUO) in the rat, a model of obstructive uropathy. HB-EGF mRNA was upregulated 5.5-fold at 4 h post-obstruction (P < 0.05) and 4.5-fold after 12 h (P < 0.05). Immunohistochemical staining for HB-EGF demonstrated an increase in protein in the distended tubules. To determine what effects increased HB-EGF might have in the obstructed kidney, we attempted to determine whether HB-EGF upregulates osteopontin and ,-smooth muscle actin (,-SMA) in the tubular line NRK-52E. Both of these molecules are increased in UUO. Osteopontin mRNA was upregulated in NRK-52E cells after 24, 48 and 72 h HB-EGF stimulation. In contrast, HB-EGF caused a downregulation of ,-SMA protein by Western blot in NRK-52E cells. When a blocking mAb against secreted HB-EGF was administered, however, there was no effect on osteopontin mRNA levels or immunohistochemical staining for ,-smooth muscle actin. These data suggest that the action of HB-EGF in UUO may be to increase osteopontin and reduce ,-smooth muscle actin expression by tubular epithelial cells by an autocrine or intracrine mechanism. By reducing ,-SMA expression, HB-EGF may also act to maintain epithelial cell morphology in this model. [source] Requirement of transforming growth factor ,,activated kinase 1 for transforming growth factor ,,induced ,-smooth muscle actin expression and extracellular matrix contraction in fibroblastsARTHRITIS & RHEUMATISM, Issue 1 2009Xu Shi-Wen Objective Fibrosis is believed to occur through normal tissue remodeling failing to terminate. Tissue repair intimately involves the ability of fibroblasts to contract extracellular matrix (ECM), and enhanced ECM contraction is a hallmark of fibrotic cells in various conditions, including scleroderma. Some fibrogenic transcriptional responses to transforming growth factor , (TGF,), including ,-smooth muscle actin (,-SMA) expression and ECM contraction, require focal adhesion kinase/Src (FAK/Src). The present study was undertaken to assess whether TGF,-activated kinase 1 (TAK1) acts downstream of FAK/Src to mediate fibrogenic responses in fibroblasts. Methods We used microarray, real-time polymerase chain reaction, Western blot, and collagen gel contraction assays to assess the ability of wild-type and TAK1-knockout fibroblasts to respond to TGF,1. Results The ability of TGF to induce TAK1 was blocked by the FAK/Src inhibitor PP2. JNK phosphorylation in response to TGF,1 was impaired in the absence of TAK1. TGF, could not induce matrix contraction or expression of a group of fibrotic genes, including ,-SMA, in the absence of TAK1. Conclusion These results suggest that TAK1 operates downstream of FAK/Src in mediating fibrogenic responses and that targeting of TAK1 may be a viable antifibrotic strategy in the treatment of certain disorders, including scleroderma. [source] | ||||||||||