Essential role of MeCP2 in the regulation of myofibroblast differentiation during pulmonary fibrosis

DNA methylation is a key mechanism for repression of gene expression, including that of α-smooth muscle actin (α-SMA) gene expression in fibroblasts. However, the trans-acting factors that interact with the methylated α-SMA gene to regulate its expression have not been identified. Using gel shift and chromatin immunoprecipitation (ChIP) assays, methyl CpG binding protein 2 (MeCP2) was shown to bind to the α-SMA gene. Suppression of MeCP2 gene expression by siRNA or its deficiency in lung fibroblasts isolated from MeCP2 knockout mice caused significant reduction of α-SMA gene expression. In contrast, transient transfection of MeCP2 expression plasmid into fibroblasts enhanced α-SMA gene expression. Moreover, in vivo studies revealed that compared to their wild type littermates, MeCP2-deficient mice exhibited significantly decreased alveolar wall thickness, inflammatory cell infiltration, interstitial collagen deposition, and myofibroblast differentiation in response to endotracheal injection of bleomycin. Thus, MeCP2 is essential for myofibroblast differentiation and pulmonary fibrosis.     

IL-17在肾间质纤维化中的作用初探

探讨白细胞介素17(IL-17)在肾间质纤维化发生发展中的作用。采用的体内实验为,以单侧输尿管梗阻(unilateral ureteric obstruction,UUO)启动纤维化病理过程。将C57BL/6小鼠分为假手术组(Sham)和单侧输尿管梗阻(unilateral ureteric obstruction,UUO)组,分别于术后第1、3、7天处死,留取手术侧肾组织。采用HE、PAS、PASM、Masson染色评价肾间质组织病理变化。以免疫组化、实时荧光定量PCR(qRT-PCR)法检测α平滑肌肌动蛋白(α-SMA)表达水平;酶联免疫吸附试验(ELISA)检测IL-17在肾组织中的表达情况。体外实验为,分离培养C57BL/6小鼠肾成纤维细胞,转化生长因子β1(TGF-β1)刺激使其转化为肌成纤维细胞,继而用蛋白免疫印迹法(western blotting)检测IL-17的刺激下α-SMA表达水平。结果显示,组织病理学检查显示随着梗阻时间延长,炎性细胞浸润明显,肾小管萎缩,间质面积增大,Ⅰ型胶原和α-SMA增多。PCR检测显示α-SMA mRNA表达增多。但ELISA结果显示肾组织中IL-17含量呈下降趋势。Western blot结果表明肌成纤维细胞在IL-17的刺激下,α-SMA蛋白水平显著下降。实验说明,单侧输尿管梗阻手术可导致相应侧肾组织发生纤维化病变,但肾组织中IL-17含量与纤维化病变并不一致,在体外实验中IL-17可下调肌成纤维细胞表达的α-SMA。     

小鼠胚胎气道平滑肌发育的形态学观察

目的 探讨肌特异性蛋白质在小鼠胚胎气道平滑肌的表达特点. 方法 用抗α-平滑肌肌动蛋白(α-SMA)、抗α-横纹肌肌动蛋白(α-SCA)和抗结蛋白(Desmin)单克隆抗体,对胎龄10～18d小鼠胚胎连续石蜡切片进行免疫组织化学显色. 结果 胎龄11 ～12d,前肠分隔为腹侧的气管和背侧的食管.胎龄12d,气管起始段后壁出现α-SMA阳性细胞,提示气管平滑肌开始发育,随着向气管下段延伸,α-SMA阳性逐渐减弱,肺静脉周围仅见极少量散在的α-SMA和α-SCA阳性细胞.胎龄13d,气管平滑肌α-SMA表达增强,并开始表达较弱的α-SCA和Desmin.胎龄14d,互为镜像的“C”形α-SMA阳性平滑肌表达出现在左、右支气管壁,α-SCA和Desmin的表达强度弱于α-SMA,此时肺静脉壁呈α-SMA强阳性表达.胎龄15d,α-SMA阳性平滑肌出现在细支气管壁.胎龄17～18d,平滑肌发育已延伸至终末细支气管,并显α-SMA阳性表达,而α-SCA和Desmin表达强度开始减弱. 结论 气道平滑肌发育始于胎龄12d气管上段,逐渐向下段延伸,胎龄18d,延伸至终末细支气管;Desmin的表达标志着平滑肌细胞骨架结构形成和气道平滑肌逐渐发育成熟,有助于气道平滑肌缓慢收缩功能的完善;气道平滑肌的发育早于肺静脉管壁平滑肌.     

Progression of renal fibrosis in congenital CKD model rats with reduced number of nephrons

A congenital reduction in the number of nephrons is a critical risk factor for both onset of chronic kidney disease (CKD) and its progression to end-stage kidney disease (ESKD). Hypoplastic kidney (HPK) rats have only about 20% of the normal number of nephrons and show progressive CKD. This study used an immunohistological method to assess glomerular and interstitial pathogenesis in male HPK rats aged 35–210 days. CD68 positive-macrophages were found to infiltrate into glomeruli in HPK rats aged 35 and 70 days and to infiltrate into interstitial tissue in rats aged 140 and 210 days. HPK rats aged 35 and 70 days showed glomerular hypertrophy, loss of normal linear immunostaining of podocine, and increased expression of PDGFr-β, TGF-β, collagens, and fibronectin, with all of these alterations gradually deteriorating with age. α-SMA-positive myofibroblasts were rarely detected in glomerular tufts, whereas α-SMA-positive glomerular parietal epithelium (GPE) cells were frequently observed along Bowman’s capsular walls. The numbers of PDGFr-β-positive fibroblasts in interstitial tissue were increased in rats aged 35 days and older, whereas interstitial fibrosis, characterized by the increased expression of tubular PDGF-BB, the appearance of myofibroblasts doubly positive for PDGFr-β and α-SMA, and increased expression of collagens and fibronectin, were observed in rats aged 70 and older. These results clearly indicate that congenital CKD with only 20% of nephrons cause renal fibrosis in rats.     

CD34<Superscript>+</Superscript> fibrocytes in chronic cystitis and noninvasive and invasive urothelial carcinomas of the urinary bladder

CD34⁺ fibrocytes are constitutive elements of the connective tissue where they play a role in matrix synthesis and tumor-associated stromal remodeling. Secreted protein, acidic, and rich in cysteine (SPARC) is a pivotal mediator of stromal remodeling precipitated by invasive carcinomas. The present study was undertaken to investigate CD34⁺ fibrocytes in the stroma of the tumor-free urinary bladder, chronic cystitis, and urothelial carcinomas together with stromal expression of α-smooth muscle actin (α-SMA), CD117, and SPARC. In tumor-free urinary bladder and chronic cystitis, CD34⁺ fibrocytes were found in the deep lamina propria and tunica muscularis, whereas the superficial lamina propria disclosed a CD34-negative and α-SMA-positive fibrocyte-like cell. Invasive urothelial carcinomas revealed a complete loss of CD34⁺ fibrocytes and concomitant appearance of α-SMA-reactive myofibroblasts which showed strong expression of SPARC. CD117 expression of tumor-free and tumor-associated stroma revealed no differences. We in this study for the first time describe CD34⁺ fibrocytes in the urinary bladder and an up-to-now unknown population of α-SMA-positive fibrocytes exclusively occurring in the superficial lamina propria. Stromal remodeling associated with invasive carcinomas in the urinary bladder is characterized by a loss of CD34⁺ fibrocytes paralleled by a gain of α-SMA-positive myofibroblasts and increased expression of SPARC.     

Podoplanin, α-Smooth Muscle Actin or S100A4 Expressing Cancer-Associated Fibroblasts Are Associated with Different Prognosis in Colorectal Cancers

The interactions between the tumor microenvironment and tumor cells determine the behavior of the primary tumors. Whether cancer-associated fibroblasts (CAF) have a tumor progressive or a protective role likely depends on the type of tumor cells and the CAF subpopulation. In the present study, we analyzed the prognostic significance of CAF subpopulations in colorectal cancer (CRC). CAF phenotypes were analyzed in 302 CRC patients by using antibodies against podoplanin (PDPN), α-smooth muscle actin (α-SMA), and S100A4. The relationship between the CAF phenotypes and 11 clinicopathological parameters were evaluated and their prognostic significance was analyzed from the disease-free and overall survival times. We observed that at the tumor invasive front, PDPN CAFs were present in 40% of the cases, and S100A4 or α-SMA CAFs were detected in all the cases. PDPN/S100A4 and α-SMA/S100A4 dual-stained CAFs were observed in 10% and 40% of the cases, respectively. The PDPN⁺ CAFs were associated with 6 favorable clinicopathological parameters and prolonged disease-free survival time. The PDPN^-/α-SMA^high CAFs were associated with 6 aggressive clinicopathological parameters and tended to exhibit shorter disease-free survival time. On the other hand, the PDPN^-/S100A4^high CAFs were associated with 2 tumor progression parameters, but not with disease prognosis. The PDPN⁺ CAF phenotype is distinct from the α-SMA or S100A4 CAFs in that it is associated with less aggressive tumors and a favorable prognosis, whereas the PDPN^-/α-SMA^high or PDPN^-/S100A4^high CAFs are associated with tumor progression in CRC. These findings suggest that CAFs can be a useful prognostic biomarker or potential targets of anti-cancer therapy in CRC.     

FHL2 expression in peritumoural fibroblasts correlates with lymphatic metastasis in sporadic but not in HNPCC-associated colon cancer

Four and a half LIM domain protein-2 (FHL2) is a component of the focal adhesion structures and has been suggested to have an important role in cancer progression. This study analyses the role of FHL2 in peritumoural fibroblasts of sporadic and hereditary non-polyposis colorectal cancer (HNPCC). Tissue specimens of 48 sporadic and 49 hereditary colon cancers, respectively, were stained immunohistochemically for FHL2, transforming growth factor (TGF)-β1 ligand and α-SMA. Myofibroblasts at the tumour invasion front co-expressed α-SMA and FHL2. Sporadic colon cancer but not HNPCC cases showed a correlation between TGF-β1 expression of the invading tumour cells and FHL2 staining of peritumoural myofibroblasts. Overexpression of FHL2 in peritumoural myofibroblasts correlated to lymphatic metastasis in sporadic colon cancer but not in HNPCC. In cultured mouse fibroblasts, TGF-β1 treatment induced myofibroblast differentiation, stimulated FHL2 protein expression and elevated number of migratory cells in transwell motility assays, suggesting that FHL2 is regulated downstream of TGF-β. Physical contact of colon cancer cells and myofibroblasts via FHL2-positive focal adhesions was detected in human colon carcinoma tissue and in co-culture assays using sporadic as well as HNPCC-derived tumour cell lines. Our data provide strong evidence for an important role of FHL2 in the progression of colon cancers. Tumour-secreted TGF-β1 stimulates FHL2 protein expression in peritumoural fibroblasts, probably facilitating the invasion of tumour glands into the surrounding tissue by enhanced myofibroblast migration and tight connection of fibroblasts to tumour cells via focal adhesions. These findings are absent in HNPCC-associated colon cancers in vivo and may contribute to a less invasive and more protruding tumour margin of microsatellite instable carcinomas.     

前列腺增生组织中间质细胞增殖和表型转化与雌激素受体α表达的关系

目的 比较人正常前列腺(NP)和前列腺增生(BPH)中间质细胞标记蛋白、增殖细胞核抗原(PCNA)和雌激素受体α(ERα)的表达差异,并检测BPH组织间质细胞标记蛋白与PCNA或ERα同时呈阳性染色的细胞.方法 对4例NP和8例BPH连续切片应用免疫组织化学方法,观察波形蛋白(vimentin)、α-平滑肌肌动蛋白(α-SMA)、肌球蛋白(myosin)、PCNA和ERa的表达定位.结果 与NP相比在BPH中,α-SMA阳性染色细胞显著增加;波形蛋白在间质中阳性染色细胞有所增加,在腺泡基底层及临近腺泡外层间质中阳性染色细胞明显增加;在临近腺泡外的数层间质细胞中肌球蛋白和ERα由部分阳性变为完全阴性染色,而在远离腺泡的间质中其阳性染色细胞由散在斑块状分布变为簇状密集排列;PCNA在间质中阳性染色细胞有所增加,在基底细胞层中阳性染色细胞显著增加.连续切片免疫组织化学染色显示,在腺泡上皮基底层存在PCNA与波形蛋白、ERα共定位的细胞;在间质中存在肌球蛋白与ERα共定位的细胞.结论 与NP相比,BPH间质细胞表型发生明显变化,且其增殖和表型转化与ERα表达定位的改变密切相关.     

α-平滑肌肌动蛋白在人胚心流出道早期发育中的表达

目的 探讨人胚早期心流出道心肌和流出道心内膜垫内α-平滑肌肌动蛋白(α-SMA)的表达规律及其意义. 方法 32例C10～C16期[Carnegie分期法,受精后(22±1～37)d]人胚心连续切片,经抗α-SMA、抗α-横纹肌肌动蛋白(α-SCA)、抗肌球蛋白重链(MHC)抗体免疫组织化学染色,观察流出道重塑过程中α-SMA在心肌与心内膜垫内的表达规律. 结果 人胚发育C10～C15期,心包腔背侧脏壁上皮不断分化为心肌细胞添加至流出道远端,这些心肌细胞α-SMA的表达早于α-SCA和MHC.C16期,流出道嵴近心肌处出现α-SMA强阳性细胞,相邻的心肌细胞伸出突起与其相连.C12～C15期,α-SMA阳性细胞逐渐迁入流出道心内膜垫内,同时可见流出道内皮转为α-SMA阳性,向间充质细胞分化.不同来源的间充质细胞共同参与形成螺旋状流出道嵴. 结论 α-SMA可作为心肌细胞早期分化的标志;流出道嵴内α-SMA阳性细胞可能部分来自神经嵴,部分为正在向间充质细胞分化的内皮细胞.     

伊马替尼减轻DOCA诱导的大鼠心肌纤维化与PDGFs/PDGFRs信号通路有关

 目的：探讨血小板源性生长因子（PDGFs）/PDGF受体（PDGFRs）信号通路拮抗剂伊马替尼（IMA）减轻醋酸去氧皮质酮（DOCA）诱导的盐敏感性高血压大鼠心肌纤维化的作用机制及PDGFs/PDGFRs信号通路在其中的作用。方法：60只雄性SD大鼠行右肾切除术,术后予以1%氯化钠和0.1%氯化钾饮水4周并随机分成3组：对照组、实验组（DOCA组）和治疗组（DOCA+IMA组）。使用尾套法每2周测定1次大鼠动脉收缩压（SBP）,苦味酸-天狼星红染色观察大鼠心肌间质纤维化程度和心肌血管周围胶原面积（PVCA）/血管腔面积（VA）比值,实时荧光定量PCR法检测心肌组织成纤维细胞特异蛋白1（FSP-1）、α-平滑肌肌动蛋白(α-SMA)、前胶原蛋白Ⅰ（procollagen Ⅰ）、前胶原蛋白Ⅲ（procollagen Ⅲ）、PDGFRα和PDGFRβ的mRNA含量,免疫组化法观察心肌组织波形蛋白（vimentin）、α-SMA、PDGFRα、PDGFRβ及磷酸化的PDGFRβ（p-PDGFRβ）的蛋白表达,免疫荧光法定位PDGFRα和PDGFRβ表达的细胞类型。结果：（1）干预第14天和第28天血压测定结果显示DOCA及DOCA+IMA组大鼠的SBP均明显高于对照组（P<0.01）,而DOCA组与DOCA+IMA组的SBP无显著差异（P>0.05）。干预第28天,DOCA组心肌间质纤维化程度和PVCA/VA比值明显高于对照组（P<0.01）,DOCA+IMA组心肌间质纤维化程度和PVCA/VA比值虽高于对照组（P<0.05）,但较DOCA组显著减小（P<0.01）。（2）干预第14天,DOCA组的PDGFRα和PDGFRβ表达较对照组增加（P<0.01）,DOCA+IMA组的PDGFRα和PDGFRβ 表达较DOCA组减少(P<0.01）。干预第28天,与对照组相比,DOCA组的PDGFRβ、p-PDGFRβ、FSP-1、α-SMA、procollagenⅠ和procollagen Ⅲ 表达明显增加（P<0.01）,而PDGFRα 的表达未见明显增加,组内比较显示PDGFRβ 表达大于PDGFRα,DOCA+IMA组PDGFRβ、p-PDGFRβ、FSP-1、α-SMA、procollagenⅠ和procollagen Ⅲ 表达较DOCA组减少（P<0.01）。（3） 干预第28天,对照组大鼠心脏间质主要是vimentin阳性的成纤维细胞,α-SMA表达很少,DOCA组大鼠α-SMA阳性的梭形细胞（肌成纤维细胞）数量明显增加（P<0.01）,DOCA+IMA组较DOCA组肌成纤维细胞数量均减少（P<0.05）。（4）在成纤维细胞和肌成纤维细胞中检测到的PDGFRα蛋白表达呈阳性,而在血管平滑肌细胞（VSMCs）中未检测到。PDGFRβ蛋白不仅在成纤维细胞和肌成纤维细胞中表达呈阳性,而且在VSMCs中也有表达。结论: 在DOCA诱导的盐敏感性高血压大鼠心肌纤维化中,PDGFRα主要在心肌纤维化早期发挥作用,而PDGFRβ在心肌纤维化的全程均起作用。PDGFRα和PDGFRβ表达定位于心脏成纤维细胞和肌成纤维细胞,伊马替尼能够减少肌成纤维细胞的数量,表明伊马替尼很可能通过抑制PDGFs/PDGFRs信号通路,减少成纤维细胞的增殖和转化生成肌成纤维细胞,从而减轻心肌纤维化。     

ROCK抑制剂对青光眼术后瘢痕形成的作用机制

目的：探讨Rho 相关卷曲螺旋形成蛋白激酶（ROCK）抑制剂对青光眼手术后瘢痕形成的影响,分析 ROCK抑制剂对瘢痕修复的作用机制。方法：健康大鼠分为模型组和ROCK抑制剂组（RR组）,采用MTT法测 定瘢痕组织中成纤维细胞增殖情况,RT-PCR 检测滤过道瘢痕组织转化生长因子-β1（TGF-β1）、α 平滑肌肌动蛋 白（α-SMA）、ROCK mRNA表达,免疫组织化学检测白细胞介素（IL）-1β（IL-1β）、α-SMA 蛋白阳性表达,免 疫印迹检测IL-1β、IL-6、血管内皮生长因子（VEGF）、α-SMA 蛋白表达。结果：模型组成纤维细胞的抑制率低 于RR组的抑制率,差异有统计学意义。RT-PCR 检测结果显示模型组TGF-β1、ROCK、α-SMA mRNA 的表达高 于RR组。免疫组织化学检测结果显示RR组IL-1β、α-SMA 的阳性表达显著低于模型组。免疫印迹检测结果显示 模型组IL-1β、IL-6、VEGF、α-SMA 的表达水平高于RR组,差异均有统计学意义。结论：ROCK抑制剂可通过 降低TGF-β1 mRNA、ROCK mRNA、IL-1β、IL-6、VEGF、α-SMA 蛋白的表达进而抑制成纤维细胞的增殖,阻 碍青光眼术后瘢痕的形成。     

Thy-1 expression,a possible marker of early myofibroblast development,in renal tubulointerstitial fibrosis induced in rats by cisplatin

Interstitial fibrosis is regarded as the common final pathway in chronic renal failure. Myofibroblasts play an important role in the renal fibrosis through producing extracellular matrices. In addition to expressions of cytoskeletons such as vimentin, desmin and α-smooth muscle actin (α-SMA), Thy-1 expression was investigated in cisplatin-induced rat renal interstitial fibrosis, to clarify the characteristics of myofibroblasts. Immunohistochemically, myofibroblasts in the renal fibrotic lesions reacted to vimentin, desmin and α-SMA in varying degrees, and the expression degrees were increased with advancing fibrosis. Vimentin expression was the greatest and the increased expression retained even in scar at end stages, whereas desmin and α-SMA expressions were almost completely decreased in scar. In double immunofluorescence, there were myofibroblasts reacting to both vimentin/desmin, desmin/α-SMA or α-SMA/vimentin, indicating that renal myofibroblasts can simultaneously express different cytoskeletons. Thy-1 expression in renal myofibroblasts was increased according to progressing fibrosis; however, the increased expression was decreased in scar, similar to desmin and α-SMA expressions. Some myofibroblasts expressing Thy-1 reacted simultaneously to vimentin or desmin, but there were no cells reacting to both Thy-1 and α-SMA. Because well-differentiated myofibroblasts are characterized mainly by α-SMA expression and the pericytes (immature stromal stem cells) showed a positive reaction to Thy-1, renal myofibroblasts might be originated from immature mesenchymal cells through loosing Thy-1 expression. This study for the first time shows that renal myofibroblasts can variously exhibit such mesenchymal markers as vimentin, desmin, α-SMA and Thy-1; particularly, Thy-1 immunohistochemistry would be used to detect myofibroblasts at early stages in analyzing chemically induced renal lesions.     

sTβRⅡ拮抗新生大鼠心肌成纤维细胞内TGF-β1诱导的Smad信号和肌成纤维细胞分化

目的研究可溶性转化生长因子-β1Ⅱ型受体(sTβRⅡ)对新生大鼠心肌成纤维细胞内TGF-β1诱导的Smad信号和肌成纤维细胞分化的抑制效应。方法培养新生大鼠的心肌成纤维细胞,随机分为4组:PBS对照组、TGF-β1(5ng/ml)组、sTβRⅡ(50ng/ml)组和TGF-β1+sTβRⅡ组。30min、1h和2h后,免疫细胞化学染色检测P-Smad2和Smad3的表达;24h后,免疫细胞化学染色检测α-SMA的表达。结果与PBS对照组相比,TGF-β1组P-Smad2、Smad3(核阳性率)和α-SMA的表达显著性升高(P0.05);与TGF-β1组相比,TGF-β1+sTβRⅡ组P-Smad2、Smad3(核阳性率)和α-SMA的表达明显降低(P0.05)。结论sTβRⅡ可拮抗新生大鼠心肌成纤维细胞内TGF-β1诱导的Smad2/Smad3蛋白的磷酸化与核转位,阻断Smad信号转导通路,抑制肌成纤维细胞分化。     

过表达肝/骨/肾型碱性磷酸酶对小鼠急性心肌梗死后心室重塑的影响

目的 探讨肝/骨/肾型碱性磷酸酶(ALPL)过表达对小鼠急性心肌梗死（MI）后心室重塑的影响。方法 36只8周龄雄性C57BL/6 J小鼠随机分为对照组(sham组),心肌梗死组（MI+Adv-EGFP组）和ALPL过表达组（MI+Adv-ALPL组）,每组12只。术后2周,使用心脏彩色超声测定小鼠心脏功能,HE染色观察小鼠心脏组织病理变化,Real-time PCR检测小鼠心脏ALPL mRNA表达水平, Western blotting检测ALPL、α平滑肌肌动蛋白（α-SMA）、Ⅰ型胶原蛋白（ColⅠ）和Ⅲ型胶原蛋白（ColⅢ）表达情况,苦味酸天狼猩红染色偏振光法测定各组标本胶原容积分数(CVF)和Ⅰ型/Ⅲ型胶原比值。结果 与MI组相比,过表达ALPL组小鼠心脏左室射血分数(LVEF)及左室短轴缩短率(LVFS)明显下降（P<0.05),过表达ALPL组HE染色可见心肌纤维断裂,排列紊乱,梗死区域纤维化明显,心脏组织α-SMA、ColⅠ、ColⅢ蛋白表达及CVF均显著增大（P<0.05）,同时ColⅠ/ColⅢ比值显著增加（P<0.05）。结论 ALPL过表达加重小鼠急性心肌梗死后心室病理性重塑。     

内皮素在诱导人气管上皮下成纤维细胞转分化中的作用

目的： 探讨ET-1在诱导气道上皮下成纤维细胞转分化为肌成纤维细胞过程中的作用及其信号与离子机制。方法: 将人气道上皮下成纤维细胞或种植在胶原凝胶中的成纤维细胞与经机械划伤加细菌脂多糖（LPS）刺激(L+M)的人气道上皮细胞株（16HBE）共培养，并加入ET受体A（ETRA）阻断剂BQ123或p38 MAPK、ERK1/2丝裂原活化蛋白激酶（MAPKs）特异性抑制剂，观察成纤维细胞α-平滑肌肌动蛋白（α-SMA）的表达情况与收缩反应性，以及p38 MAPK、ERK1/2信号通路的活化及其对α-SMA表达的影响；经钙离子荧光探针（Fluo-3/AM）负载，应用激光共聚焦显微镜观察成纤维细胞胞内钙的动态变化。结果: 损伤的气道上皮细胞诱导了上皮下成纤维细胞转分化为表达α-SMA、具有显著收缩反应能力的肌成纤维细胞，BQ123对其有一定的抑制效应；p38 MAPK、ERK1/2的特异性阻断剂（SB203580、PD98059）可钝化损伤上皮对成纤维细胞α-SMA表达的诱导作用。添加外源性ET-1增加成纤维细胞α-SMA表达并诱导p38 MAPK、ERK1/2信号通路的活化；同时，引起胞内钙水平的迅速上升。结论: 损伤的气道上皮细胞通过释放ET-1能够诱导上皮下成纤维细胞转分化为具有收缩反应性的肌成纤维细胞， p38 MAPK、 ERK1/2信号通路介导了这一过程，ET-1增强成纤维细胞Ca2+内流可能是启动其转分化的早期事件。     

TGF-β-induced fibroblast activation protein expression, fibroblast activation protein expression increases the proliferation, adhesion, and migration of HO-8910PM

Several studies recognize cancer-stromal fibroblasts' role in cancer-cell invasion and metastasis. Through paracrine signaling molecules, TGF-β and IL-1β, cancer cells activate stromal fibroblasts and induce the expression of fibroblast activation protein (FAP). FAP, in turn, affects the proliferation, invasion and migration of the cancer cells. We report that TGF-β and IL-1β are important factors in inducing differentiation of myofibroblasts and expression of functional markers, notably α-SMA. We discover that TGF-β is the dominant factor in promoting FAPα protein expression. This study also examines FAP's function in vitro by assaying the proliferation, migration and invasion of ovarian cancer cell line HO-8910PM.     

The effects of combined cyclic stretch and pressure on the aortic valve interstitial cell phenotype

Aortic valve interstitial cells (VIC) can exhibit phenotypic characteristics of fibroblasts, myofibroblasts, and smooth muscle cells. Others have proposed that valve cells become activated and exhibit myofibroblast or fibroblast characteristics during disease initiation and progression; however, the cues that modulate this phenotypic change remain unclear. We hypothesize that the mechanical forces experienced by the valve play a role in regulating the native phenotype of the valve and that altered mechanical forces result in an activated phenotype. Using a novel ex vivo cyclic stretch and pressure bioreactor, we subjected porcine aortic valve (AV) leaflets to combinations of normal and pathological stretch and pressure magnitudes. The myofibroblast markers α-SMA and Vimentin, along with the smooth muscle markers Calponin and Caldesmon, were analyzed using immunohistochemistry and immunoblotting. Tissue structure was analyzed using Movat’s pentachrome staining. We report that pathological stretch and pressure inhibited the contractile and possibly myofibroblast phenotypes as indicated by downregulation of the proteins α-SMA, Vimentin, and Calponin. In particular, Calponin downregulation implies depolymerization of actin filaments and possible conversion to a more synthetic (non-contractile) phenotype. This agreed well with the increase in spongiosa and fibrosa thickness observed under elevated pressure and stretch that are typically indicative of increased matrix synthesis. Our study therefore demonstrates how cyclic stretch and pressure may possibly act together to modulate the AVIC phenotype.     

呼吸内胚层相关第二生心区与小鼠胚胎流出道远端的形态发生

目的探讨小鼠胚胎呼吸内胚层相关第二生心区(PSHF)发育与流出道远端形态发生的关系。方法用免疫蛋白印迹法检测抗胰岛因子-1(ISL-1)在80例胚龄10~14 d小鼠胚胎心脏标本的表达。另用抗ISL-1、抗α-平滑肌肌动蛋白(α-SMA)及抗心肌肌球蛋白重链(MHC)抗体,对36例胚龄11~13 d小鼠胚胎心连续石蜡切片进行免疫组织化学或免疫荧光染色。结果胚龄11~12 d是ISL-1蛋白在小鼠胚胎心脏表达的高峰时段。胚龄11 d,来自鳃弓或心包腔背侧壁等处PSHF的ISL-1阳性细胞延伸进入流出道远端管壁,流出道远端管壁则失去MHC表达,呈α-SMA阳性表达;来自PSHF的ISL-1阳性细胞则围绕呼吸内胚层呈对称性锥体结构分布,锥体顶端突入动脉囊腔呈ISL-1阳性突起。胚龄11.5 d,PSHF锥体顶端进入动脉囊头侧和尾侧管壁,形成流出道远端管壁上对称的ISL-1阳性柱结构;而动脉囊腔尚未分隔,流出道远端仍为单一管道。胚龄12 d,PSHF锥体突起失去ISL-1表达,呈较强的α-SMA表达。在PSHF锥体突起与流出道嵴融合前,两者之间出现主-肺动脉孔;两者融合后则形成α-SMA阳性的暂时性主-肺动脉隔,将动脉囊分隔成MHC阴性的心包内的主动脉和肺动脉。胚龄13 d,主-肺动脉隔逐渐消失,心包内主动脉和肺动脉分离。在MHC阴性的心包内大动脉管壁上出现了α-SMA阳性的平滑肌层,仍可见少量PSHF的ISL-1阳性细胞延伸进入心包内大动脉管壁。结论在小鼠胚胎发育11~13 d,PSHF将动脉囊分隔成心包内的主动脉和肺动脉,并参与心包内大动脉的侧面管壁和对侧面管壁的分化形成。