Smad2和Smad4在家猫睾丸发育和精子发生中的表达与定位

目的 研究转化生长因子β(TGF-β)超家族的下游信号转导分子Smad2和Smad4蛋白,在不同发育阶段家猫睾丸中的表达和定位,探索Smad2和Smad4蛋白与家猫睾丸发育和精子发生的关系. 方法 应用免疫组织化学技术,研究Smad2和Smad4蛋白在幼年(n=3)、青春期(n=3)和性成熟(n=18)睾丸中的定位,并通过Western blotting技术对免疫组织化学中所用抗体的特异性进行了检测. 结果 免疫组织化学结果显示,Smad2和Smad4蛋白定位于各发育阶段家猫睾丸的生殖细胞、支持细胞和间质细胞的胞质中;Western blotting结果显示,多克隆兔抗Smad2和Smad4抗体与家猫睾丸蛋白提取物中分子量约为58kD、66kD的蛋白条带发生免疫阳性反应. 结论 Smad2和Smad4蛋白在家猫睾丸发育和精子发生的各个阶段均有表达,提示其参与睾丸发育和精子发生的调节.     

腺嘌呤致大鼠雄性不育发病机理的实验研究

目的探讨转化生长因子-β(TGF-β)超家族的细胞内信号转导分子Smad2、Smad4蛋自在腺嘌呤所致雄性不育的大鼠睾丸内定位、分布及作用机制。方法应用免疫组织化学SABC法检测正常成年及腺嘌呤(300mg／kg)灌胃后第7、14、21d大鼠睾丸中Smad2、Smad4的定位和分布,并通过图像分析系统进行统计学分析,同时应用放射免疫法测定血清中睾酮(T)、促黄体激素(LH)和促卵泡激素(FSH)的含量。结果Smad2免疫阳性产物位于实验大鼠各级生精细胞及支持细胞的胞质内,Samd4则位于间质细胞的胞质内;灌胃后第21d大鼠睾丸中Smad2、Smad4表达明显高于正常成年及7、14d大鼠,同时,血清中T较正常成年及7、14d大鼠明显降低,LH、FSH明显增高。结论腺嘌呤所致雄性不育可能与Smad2在大鼠睾丸生精细胞中表达增强及Smad4在睾丸间质细胞中表达增强,直接或间接影响睾丸的生精功能有关。     

转化生长因子-β1及其信号传导分子Smad2与Smad4在羊驼睾丸的表达

目的 研究转化生长因子-β1(TGF-β1)、Smad2、Smad4在羊驼睾丸的表达与定位,探索TGF-β1在羊驼睾丸发育及精子发生中的作用.方法 以24月龄的羊驼睾丸为研究对象,采用Western blotting技术及免疫组织化学SABC法对TGF-β1、Smad2、Smad4在羊驼睾丸的表达进行研究.结果 Western blotting结果显示,羊驼睾丸组织粗蛋白提取物中存在分子量约为25kD、52kD、62kD,与多克隆兔抗TGF-β1、Smad2、Smad4抗体发生免疫阳性反应的蛋白条带;免疫组织化学结果显示,TGF-β1、Smad2、Smad4在24月龄羊驼睾丸的间质细胞、支持细胞和各级生精细胞均有不同程度的表达.结论 TGF-β1通过Smad2与Smad4传导途径参与性成熟羊驼睾丸组织的发育与精子发生的调控.     

转化生长因子β及其受体在小鼠精子发生过程中的表达

目的观察转化生长因子β（TGFβs）及其受体（TGFβ-R）在小鼠睾丸中的表达,证实TGFβs及其受体在小鼠精子发生过程中的定位和作用机理.方法免疫组织化学染色结合显微图像定量分析和免疫荧光双重染色.结果免疫组织化学显示：TGFβ1和TGFβ2主要表达于生精小管内Ⅵ-Ⅷ期圆形精子细胞以及长形精子细胞和变态精子细胞的胞质,位于睾丸间质中的Leydig细胞胞质呈弱表达;TGFβ3仅表达于Leydig细胞,各级生精细胞未见表达.晚期精母细胞（Ⅷ期）至第Ⅹ期长形精子细胞均表达TGFβ-RⅠ;TGFβ-RⅡ仅表达于第Ⅺ期后的变态精子细胞期;而TGFβ-RⅢ则主要表达于Ⅶ-Ⅷ期圆形精子细胞和变态精子细胞胞质.免疫荧光双重染色显示：TGFβ1和TGFβ2与TGFβ-RⅢ在生精上皮最早共表达于晚期圆形精子细胞顶体极.结论 TGFβs及其受体在小鼠精子发生过程中的表达具有细胞和周期特异性,提示其在精子发生中具有重要意义.     

Smad2/Smad3蛋白在大鼠卵巢颗粒细胞中的表达及FSH对其活化的影响

目的 研究Smad2/Smad3蛋白在大鼠卵巢颗粒细胞中的表达及FSH对其活化的影响.方法 21d SD雌性大鼠,注射PMSG 20IU,48h后对卵巢颗粒细胞进行原代培养,用TGFβRⅡ抗体及不同浓度的FSH对细胞进行不同时间的处理,通过免疫细胞化学方法观察TGFβ信号通路中Smad2/Smad3和P-Smad2/P-Smad3(磷酸化Smad2/3)表达的变化.结果 1.Smad2/Smad3主要定位于卵巢颗粒细胞胞质,其活化形式P-Smad2/P-Smad3有少量表达;2.经FSH处理后, Smad2/Smad3向核内转移增多,P-Smad2/P-Smad3的表达增强,并与FSH的作用时间及剂量呈正相关性;3.TGFβRⅡ被抗体完全中和后再用FSH处理,Smad2/Smad3的核阳性率无显著增多, P-Smad2/P-Smad3的表达未见明显增强.结论 1.FSH促进Smad2/Smad3的磷酸化;2.FSH对 Smad2/Smad3的激活作用与TGFβ受体密切相关.     

大鼠睾丸Cx43蛋白表达的加龄变化

目的:研究Cx43蛋白在大鼠出生后不同周龄睾丸中表达和定位,探讨Cx43蛋白与大鼠睾丸发育和精子发生的相关性。方法:应用免疫组织化学研究Cx43蛋白在1、3、5、7、9、11、13周龄SD雄性大鼠睾丸中的表达,利用血细胞计数板检测5~13周龄精子的数量。结果:Cx43蛋白于第1周开始在支持细胞、精原细胞中表达,第3周在精母细胞中表达,第5周开始在间质细胞、精母细胞、精子细胞中表达,随周龄增加而表达增加;第5周开始出现精子,随周龄增加而增加,Cx43蛋白表达与精子数量呈正相关。结论:Cx43蛋白在大鼠睾丸发育和精子发生的各个阶段均有表达,提示其参与睾丸发育和精子发生的调节。     

人绒毛膜促性腺激素对切除颌下腺小鼠静止期精母细胞的一些影响

目的：探讨人绒毛膜促性腺激素(HCG)对切除颌下腺小鼠静止期精母细胞表皮生长因子(EGF)的表达和生精功能的影响。方法：采用组织化学和免疫组织化学技术。结果：EGF、分布在小鼠睾丸间质细胞、精原细胞、静止期精母细胞、细线期精母细胞和精子细胞。去颌下腺组EGF阳性反应静止期精母细胞数量明显减少，同时相应的生精小管的各级生精细胞也显著减少。与去颌下腺组相比，去颌下腺给药组EGF阳性反应静止期精母细胞数量明显增多，同时相应的生精小管的生精细胞也显著增多。结论：睾丸间质细胞和部分生精细胞能分泌EGF。EGF在生精小管上皮的分布与生精周期有密切关系。静止期精母细胞EGF表达减弱是切除颌下腺导致小鼠少精症的原因之一。HOG可促进静止期精母细胞表达EGF，以调节精子发生过程。     

磷酸化的丝裂原活化蛋白激酶在大鼠睾丸的表达

目的研究丝裂原活化蛋白激酶(MAPKs)的3个亚家族成员细胞外信号调节激酶(ERK)、c-Jun N-端激酶(JNK)和p38 MAPK的活化形式在睾丸中的定位,了解MAPKs在生精过程中所起的作用。方法免疫组织化学方法检测正常大鼠睾丸中磷酸化的p-ERKJ、NK、p38 MAPK的表达情况。结果正常大鼠睾丸中p-ERK主要分布于精原细胞、细线前期到粗线期的初级精母细胞以及9~12期长形精子细胞的细胞核,p-JNK则主要位于支持细胞与支持细胞、支持细胞与生精细胞(尤其是19期精子细胞)之间,而p-p38 MAPK除了在生精小管的部分细胞胞质中有分布外,其表达最明显的部位是在间质细胞的细胞质。结论ERKJ、NK和p-38 MAPK分别定位于正常大鼠睾丸内的不同部位,提示MAPKs不同的亚家族成员分别在精子发生的不同环节中发挥主要作用。ERK可能参与生精细胞增殖、分化的信号转导,JNK则可能通过调节细胞的黏附而最终影响生精细胞的迁移与精子释放过程,而p38 MAPK除了可能与JNK一起参与精子释放的调节外,最主要的作用可能是睾酮合成分泌的调节。     

Smad3基因敲除小鼠肾Smad2和p-Smad2表达的变化

目的:观察Smad3基因敲除小鼠肾Smad2和p-Smad2表达的变化,探讨Smad3基因敲除小鼠肾是否有Smad2和p-Smad2代偿性增加.方法:4只Smad3基因敲除小鼠,10只野生型小鼠,应用免疫组织化学显色技术,检测Smad2和p-Smad2蛋白的定位和表达情况,并用Motic病理图像分析系统对图像进行半定量分析.结果:野生型小鼠肾Smad2蛋白在肾远端小管和肾集合管细胞胞质中有广泛弱表达,p-Smad2蛋白在肾远端小管和肾集合管细胞胞质、胞核中也有弱表达,而Smad3基因敲除小鼠的Smad2和p-Smad2的表达比野生型小鼠有显著升高.结论:Smad3基因敲除能引起小鼠肾Smad2和p-Smad2表达的代偿性增加.     

卵泡刺激素调节大鼠卵巢颗粒细胞中Smad2/Smad3蛋白的表达及磷酸化

目的:研究卵泡刺激素(FSH)对大鼠卵巢颗粒细胞中Smad2/Smad3蛋白的调节。方法:21dSD雌鼠,腹腔注射孕马血清20IU,对颗粒细胞进行原代培养,用转化生长因子β受体Ⅱ(TβRⅡ)抗体中和卵巢颗粒细胞表面TβRⅡ,以阻断TGFβ/Smads信号通路,再以不同浓度的FSH对细胞进行不同时间的处理,免疫印迹法检测TGFβ信号通路中TβRⅡ、Smad2/Smad3及P-Smad2/P-Smad3蛋白的表达。结果:TβRⅡ、Smad2/Smad3、P-Smad2/P-Smad3蛋白的表达量与FSH的作用呈时间依赖性显著增强;TGFβ/Smads信号通路被阻断后再用FSH处理,Smad2/Smad3、P-Smad2/P-Smad3蛋白的表达量没有明显变化;细胞表面TβRⅡ恢复后,Smad2/Smad3、P-Smad2/P-Smad3蛋白的表达量有少量增加。结论:FSH刺激大鼠卵巢颗粒细胞中Smad2/Smad3的表达和磷酸化;FSH对Smad2/Smad3的激活作用在相当程度上依赖于TβRⅡ。     

SMAD genes in juvenile polyposis.

Juvenile polyposis (JP) is a dominantly inherited condition characterized by the development of multiple hamartomatous tumors, juvenile polyps, in the gastrointestinal tract. The aim of this study was to clarify the role of SMAD4 in JP. DNA from four unrelated JP kindreds and three sporadic JP cases was available for mutation screening. Two truncating defects (one in a familial and one in a sporadic case) and one missense change (in a familial case) that was absent in 55 control samples were detected. To study the possibility that germline mutations in other genes encoding different components of the TGF-beta signaling pathway may be present in these JP patients, mutation analyses of the SMAD2, SMAD3, and SMAD7 genes were also performed. No mutations of these genes were detected in any of the patients. Our results confirm that SMAD4 is a gene predisposing to JP and suggest the existence of further JP loci other than the SMAD2, SMAD3, or SMAD7 genes. Genes Chromosomes Cancer 26:54-61, 1999.     

Mechanical compression upregulates MMP9 through SMAD3 but not SMAD2 modulation in hypertrophic scar fibroblasts

Purpose: Activation of transforming growth factor-β (TGF-β) signaling and matrix metalloproteinases are involved in hypertrophic scar (HS) formation. Compression therapy is known to be an effective approach for the treatment of hypertrophic scarring; however, the underlying molecular mechanisms remain poorly understood. We investigated the relationship between TGF-β signaling activation and matrix metalloproteinases in HS fibroblasts during mechanical compressive stress.

Materials and methods: Two groups of skin tissue from HS and the nearby normal tissue were obtained from surgical patients and analyzed. Primary fibroblasts from the HS tissue and normal fibroblasts were isolated. Pressure therapy was recapitulated in an in vitro three-dimensional culture model, using mechanical stress produced with the Flexcell FX-4000C Compression Plus System. Quantitative real-time PCR (qPCR) was used to analyze the gene expression profiles in skin tissue and cultured primary cells exposed to compressive stress. Knockdown of SMAD2 and SMAD3 was performed using their specific siRNA in HS and normal fibroblasts subjected to compressive stress, and gene expression was examined by qPCR and Western blot.

Results: There was a significant upregulation of the mRNA expression of matrix metalloproteinase-2 (MMP2) and MMP9 in primary HS fibroblasts in response to mechanical stress. In contrast, the mRNA levels of collagen I and collagen III were downregulated in primary HS fibroblasts compared with those in the control cells. SiRNA-mediated knockdown of SMAD3 in the primary fibroblasts exposed to mechanical stress resulted in a decrease in the expression of MMP9 compared to control cells.

Conclusion: These results demonstrate that compressive stress upregulates MMP9 by SMAD3 but not by SMAD2.     

SMAD4 mutations found in unselected HHT patients

Background

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disease exhibiting multifocal vascular telangiectases and arteriovenous malformations. The majority of cases are caused by mutations in either the endoglin (ENG) or activin receptor‐like kinase 1 (ALK1, ACVRL1) genes; both members of the transforming growth factor (TGF)‐β pathway. Mutations in SMAD4, another TGF‐β pathway member, are seen in patients with the combined syndrome of juvenile polyposis (JP) and HHT (JP‐HHT).

Methods

We sought to determine if HHT patients without any apparent history of JP, who were undergoing routine diagnostic testing, would have mutations in SMAD4. We tested 30 unrelated HHT patients, all of whom had been referred for DNA based testing for HHT and were found to be negative for mutations in ENG and ALK1.

Results

Three of these people harboured mutations in SMAD4, a rate of 10% (3/30). The SMAD4 mutations were similar to those found in other patients with the JP‐HHT syndrome.

Conclusions

The identification of SMAD4 mutations in HHT patients without prior diagnosis of JP has significant and immediate clinical implications, as these people are likely to be at risk of having JP‐HHT with the associated increased risk of gastrointestinal cancer. We propose that routine DNA based testing for HHT should include SMAD4 for samples in which mutations in neither ENG nor ALK1 are identified. HHT patients with SMAD4 mutations should be screened for colonic and gastric polyps associated with JP.     

SMAD6 is frequently mutated in nonsyndromic radioulnar synostosis

PurposeRadioulnar synostosis (RUS) can be syndromic or nonsyndromic. The genetic basis for several RUS syndromes have been reported. However, the genetic cause of nonsyndromic RUS (nsRUS) remains unknown.MethodsWe performed Giemsa (GTG) banding, Sanger sequencing, and exome sequencing on patients (n = 140) and families(n = 11) who suffered from RUS.ResultsGTG banding identified 10% RUS sporadic cases affected by sex chromosome aneuploidy. Sanger sequencing on candidate genes revealed noggin(NOG) rarely mutated in nsRUS. Exome sequencing identified 16 loss-of-function (LOF) and 6 missense variants (minor allele frequency [MAF] < 0.0001) in 22/117 nsRUS sporadic patients. Genetic association analysis found a significant association between SMAD6-LOF variants and nsRUS risk (odds ratio[OR] = 430, 95% confidence interval [CI]: 238–780, P < 0.000001). SMAD6 mutated in nsRUS was further confirmed by direct Sanger sequencing of SMAD6-coding regions on other unrelated cohorts of nsRUS cases or families. In summary, we detected 27 SMAD6 rare variants in nsRUS, most of which were LOF variants, 4 were de novo, and 3 were transmitted in families with autosomal dominant inheritance.ConclusionAs an intracellular bone morphogenetic protein (BMP) antagonist gene, SMAD6 is frequently mutated in nsRUS.NOG, which encodes an extracellular BMP antagonist, is rarely mutated in nsRUS. This work is the first genetic study on nsRUS.     

Gastric juvenile polyposis associated with germline SMAD4 mutation

We treated a 39-year-old woman with hypoproteinemia and anemia who had profuse gastric polyposis. Radiographic and endoscopic examination showed numerous polyps restricted to the stomach. The patient had pulmonary arteriovenous malformations in the left lung. Histological examination of the resected stomach revealed the gastric polyposis to be composed of cystic dilatation of the glands with small areas of adenocarcinoma. These findings were compatible with gastric juvenile polyposis (GJP) accompanied by gastric cancer. Analysis of genomic DNA revealed that the patient had truncating mutation of SMAD4, a responsible gene for juvenile polyposis (JP). Our case suggests that SMAD4 is possibly a responsible gene for GJP.