Lactoferrin Prevents Hepatic Injury and Fibrosis via the Inhibition of NF-κB Signaling in a Rat Non-Alcoholic Steatohepatitis Model

Non-alcoholic steatohepatitis (NASH) can cause liver cirrhosis and hepatocellular carcinoma (HCC), with cases increasing worldwide. To reduce the incidence of liver cirrhosis and HCC, NASH is targeted for the development of treatments, along with viral hepatitis and alcoholic hepatitis. Lactoferrin (LF) has antioxidant, anti-cancer, and anti-inflammatory activities. However, whether LF affects NASH and fibrosis remains unelucidated. We aimed to clarify the chemopreventive effect of LF on NASH progression. We used a NASH model with metabolic syndrome established using connexin 32 (Cx32) dominant negative transgenic (Cx32ΔTg) rats. Cx32ΔTg rats (7 weeks old) were fed a high-fat diet and intraperitoneally injected with dimethylnitrosamine (DMN). Rats were divided into three groups for LF treatment at 0, 100, or 500 mg/kg/day for 17 weeks. Lactoferrin significantly protected steatosis and lobular inflammation in Cx32ΔTg rat livers and attenuated bridging fibrosis or liver cirrhosis induced by DMN. By quantitative RT–PCR, LF significantly down-regulated inflammatory (Tnf-α, Il-6, Il-18, and Il-1β) and fibrosis-related (Tgf-β1, Timp2, and Col1a1) cytokine mRNAs. Phosphorylated nuclear factor (NF)-κB protein decreased in response to LF, while phosphorylated JNK protein was unaffected. These results indicate that LF might act as a chemopreventive agent to prevent hepatic injury, inflammation, and fibrosis in NASH via NF-κB inactivation.     

连接蛋白36研究进展

Cx36是连接蛋白家族新成员,主要分布在脑组织、视网膜的神经元,也在非神经组织,如胰岛β细胞、肾上腺嗜铬细胞表达。由Cx36组成的缝隙连接是神经细胞电信号转导必需的,对胰腺胰岛素的分泌和肾上腺儿茶酚胺的释放也起重要作用。它的异常与青少年癫痫、遗传性感觉反应刺激异常有关,对学习记忆过程也有影响。     

非霍奇金淋巴瘤侵犯骨髓时Cx43表达情况

目的:研究非霍奇金淋巴瘤(non-Hodgkin' s lymphoma,NHL)骨髓侵犯患者骨髓病灶中间隙连接蛋白（connexin,Cx）43表达情况。 方法:选取我院确诊的非霍奇金淋巴瘤骨髓侵犯患者26例,骨髓组织中查见呈灶性分布且已通过免疫组化证实为反应性淋巴细胞增生的患者9例,正常骨髓组织10例行免疫组化染色,根据阳性率及阳性程度评分后进行统计学分析。 结果:Cx43在NHL样本中的阳性率（30.8%）低于在反应性淋巴细胞增生样本（88.9%）及正常样本（100%）中的阳性率,差异有统计学意义（P<0.05）。而反应性淋巴细胞增生样本和正常样本间Cx43阳性率无统计学意义（P>0.05）,但反应性淋巴细胞增生样本的阳性积分明显低于正常样本（P<0.05）。结论:非霍奇金淋巴瘤骨髓侵犯时病灶处Cx43表达情况显著低于反应性淋巴细胞增生及正常骨髓组织。     

大鼠脑缺血再灌注损伤后Cx43蛋白的表达模式

目的：建立大鼠大脑中动脉闭塞（MCAO）缺血再灌注模型,探索再灌注后Cx43蛋白的表达模式。方法75只大鼠随机分为MCAO组（60只）和假手术组（15只）。MCAO组均行MCAO手术,术后根据缺血再灌注时间分为0.5、4、12、24 h 4个亚组,每组15只;假手术组不插入线栓。各组进行改良神经损伤严重程度评分（mNSS）、脑组织TTC染色及神经元尼式染色,Western blot及免疫组织化学方法检测各组脑组织Cx43蛋白的表达并进行统计学分析。结果 MCAO组造模成功率75%。MCAO组大鼠mNSS评分明显高于假手术组（P＜0.05）,脑梗死面积增加,额顶叶皮质区神经元大量损伤。Western blot结果显示：假手术组及MCAO 0.5、4、12、24 h组Cx43表达量分别为0.23±0.12、0.58±0.18、0.78±0.07、0.61±0.05和0.27±0.07, MCAO 0.5、4、12 h组与假手术组差异均有统计学意义（P＜0.05）,而MCAO 24 h组与假手术组差异无统计学意义（P＞0.05）。免疫组化结果显示：MCAO组侧脑室下区Cx43的表达在0.5 h开始升高,4 h达高峰,12 h逐渐下降,直至24 h恢复基线水平;与Western blot结果一致。结论 Cx43蛋白在脑缺血性再灌注损伤发生、发展中起重要作用。     

全反式维甲酸对急性白血病骨髓基质细胞GJIC功能的影响

目的 观察在全反式维甲酸(ATRA)作用下急性白血病骨髓基质细胞间连接蛋白43(Cx43)表达的变化及通讯功能的改变.方法 体外培养急性白血病骨髓基质细胞,传代后加入ATRA(1×10-5mol/L),采用细胞免疫化学及流式细胞术检测加药前后Cx43表达的变化;采用细胞划痕染料传输技术比较二者间隙连接细胞间通讯(GJIC)功能的差异.结果 急性白血病骨髓基质细胞加药前后,细胞免疫化学方法检测Cx43表达的阳性率分别为47.2%±2.04%和54.5%±5.66%,流式细胞术检测Cx43的含量为38.75%±23.95%和49.5%±5.46%;加药后染料可传输至4～5列细胞,明显高于加药前(P＜0.01).结论 加入ATRA后,急性白血病骨髓基质细胞间通讯功能较加药前明显增强.     

Intercellular communication via gap junctions in activated rat hepatic stellate cells

BACKGROUND AND AIMS: Gap junctional communication was studied in quiescent and activated hepatic stellate cells. METHODS: Connexin expression and intercellular dye transfer were studied in rat hepatic stellate cells in culture and in vivo. RESULTS: Protein expression of connexin 43 was up-regulated in activated hepatic stellate cells in vivo and in vitro and was mainly localized on the cell surface, whereas connexin 26 was found intracellularly. In contrast to hepatocytes, hepatic stellate cells do not express connexin 32. Confluent hepatic stellate cells in culture communicate via gap junctions, resulting in lucifer yellow transfer and propagation of intracellular calcium signals. Phorbol ester induces a protein kinase C-dependent hyperphosphorylation and degradation of connexin 43 and inhibits intercellular communication on a short-term time scale. At the long-term level, vitamin D(3) , lipopolysaccharide, thyroid hormone T(3), dexamethasone, platelet-derived growth factor, endothelin 1, and interleukin 1beta up-regulate connexin 43 protein and messenger RNA expression and enhance intercellular communication. Slight down-regulation of connexin 43 is observed in response to vitamin A. Connexin 43 induction by endothelin 1 is inhibited by both endothelin A and endothelin B receptor antagonists. In coculture systems, hepatic stellate cells communicate with each other, which is suggestive of a syncytial organization, but no communication was found between hepatic stellate cells and other liver cell types. As shown by immunohistochemistry and electron microscopy, gap junctions are formed between activated hepatic stellate cells in vivo. CONCLUSIONS: Gap junctional communication occurs between hepatic stellate cells, is enhanced after activation, and underlies complex regulation by cytokines, hormones, and vitamins.     

间隙连接蛋白43突变与皮肤疾病相关性研究

间隙连接蛋白(Cx)在保证细胞间物质信息传递及维持皮肤屏障稳态方面发挥着重要作用,其基因突变,甚至表达水平异常均会引起多种疾病,严重影响患者生活质量。在编码人类Cx家族的21个基因中,与Cx基因突变相关的临床伴随疾病至少有14种。其中,Cx43分布最广,不仅在大多数器官组织中均有报道,也是伤口愈合、皮肤角质化,以及皮肤肿瘤发展等重要生理病理过程中的关键调控节点。本文总结了近年来Cx43基因(GJA1)在皮肤屏障中的作用、GJA1基因突变相关皮肤疾病及其潜在致病机制这几个快速发展领域中的研究成果,以期为Cx43临床伴发疾病防治及相关研究提供参考。     

病理性瘢痕成纤维细胞中连接蛋白43的免疫电镜观察

目的：观察连接蛋白43（Connexin43,Cx43）在病理性瘢痕成纤维细胞中的表达,探讨Cx43及其构成的缝隙连接在病理性瘢痕中的调控作用。方法：取正常皮肤2例、正常修复组织2例、增生性瘢痕5例、瘢痕疙瘩5例,用特异性抗体（Cx43）作为标记物,用胶体金标记的IgG作示踪物进行免疫电镜观察Cx43的分布与表达,并对其进行定位,同时观察不同标本成纤维细胞的超微结构变化。结果：Cx43在正常修复组织及正常皮肤成纤维细胞的胞浆及近胞膜上表达,且明显集中于粗面内质网;Cx43在增生性瘢痕成纤维细胞的表达明显减少,粗面内质网中见到少许Cx43金颗粒的聚集;瘢痕疙瘩成纤维细胞仅在胞浆中见到少许Cx43散在金颗粒。结论：成纤维细胞Cx43的表达下调可能是造成病理性瘢痕组织中成纤维细胞间缝隙连接细胞间通讯异常,从而导致病理性瘢痕发生的因素之一。     

血管紧张素Ⅱ对心肌细胞缝隙连接蛋白Cx43表达的时相性调控

目的研究血管紧张素Ⅱ(AngⅡ)诱导心肌细胞肥大后缝隙连接蛋白Cx43表达的变化规律和机制。方法分离培养大鼠心肌细胞后分为正常对照组、AngⅡ组和缬沙坦组,用Westernblot和免疫荧光法观察不同时间(12、24、48、72h)和不同浓度(1.0×10-9～1.0×10-5mol/L)下心肌细胞Cx43表达的变化,采用免疫荧光法检测3组心肌细胞24和72hCx43的表达。结果AngⅡ组心肌细胞较正常对照组明显肥大,蛋白含量增加。AngⅡ组心肌细胞在24～48hCx43表达上调,72h则明显下调,较正常对照组减少30%,而且在AngⅡ作用下呈浓度依赖性下调,24hAngⅡ组荧光阳性细胞数较正常对照组和缬沙坦组明显上调,72h则较其他组明显下调。缬沙坦可拮抗AngⅡ对Cx43表达的作用。结论AngⅡ诱导心肌细胞肥大过程中Cx43的表达出现一定时相性变化,并和AngⅡ呈明显的量效关系,提示AngⅡ可能通过AT1受体调控Cx43的表达而参与心肌细胞缝隙连接重构。