miRNA-21 plays an important role in necrotizing enterocolitis

IntroductionTo investigate the role and mechanism of miRNA-21 in necrotizing enterocolitis (NEC).Material and methodsCollecting 30 pairs of newborn and NEC children and measuring the miRNA-21 expression in the serum of 30 pairs. Thirty neonatal Wistar rats were randomized to 3 groups: NC, Model and miRNA groups. The rats of model and miRNA groups were based on NEC model groups, after the fabricated NEC model of neonatal rats. The Model group was treated with normal saline and the miRNA group was injected with miRNA-21 from the abdomen. On the 4^th day, all the rats were executed. The intestinal tissue located at the boundary of the ileum and cecum was sampled for histology and cell apoptosis. The relative protein (PTEN, PI3K, AKT and GSK-3β) expression levels of difference groups were evaluated by WB assay.ResultsIn the clinical data, the miRNA-21 gene expression of NEC children was significantly up-regulation compared with that of normal newborns (p < 0.05). In the rat experiments, compared with the NC group, the pathology and cell apoptosis of the Model group showed significant deterioration (p < 0.05) and relative protein (PTEN, p-PI3K, p-AKT and p-GSK-3β) expression levels were significantly different (p < 0.05, respectively). However, the pathology and cell apoptosis of colonic tissue were significantly improved (p < 0.05), the PTEN and p-GSK-3β protein expression levels were significantly suppressed (p < 0.05) and p-PI3K and p-AKT protein expression levels were significantly increased (p < 0.05, respectively) with miRNA-21 over-expression compared with the Model group.ConclusionsmiRNA might be a biological marker and therapeutic target in NEC diagnosis and treatment.     

The conserved carboxyl terminus of human parainfluenza virus type 2 V protein plays an important role in virus growth

Our previous results have shown that some residues of V protein-specific domain in human parainfluenza virus type 2 (hPIV2) are essential not only for STAT protein degradation but also for promoting virus growth. Here, we demonstrated that the virus growth of these recombinant hPIV2s (rPIV2) expressing mutated V proteins were improved in HeLa cell transiently expressing the wild-type V protein, but not in the cells constitutively expressing it. Consequently, we identified the region of the V protein that is essential for its oligomerization and for complex formation with NP protein. We also identified a host protein, AlP1/Alix, involved in apoptosis and efficient budding of several enveloped viruses as an interacting partner of the V and NP proteins. Depletion of AIP1/Alix by small interfering RNA suppressed virus growth. These data suggest that the conserved carboxyl terminus of the V protein plays an important role in virus growth.     

Interleukin 1 plays a major role in the development of Th2-mediated immunity

Expulsion of the gastrointestinal nematode Trichuris muris is mediated by a T helper (Th)2-type response, involving interleukin (IL)-4, IL-9 and IL-13. Here, we show that Th2 response-associated resistance is dependent on the presence of IL-1alpha and IL-1beta. When lymph node cells from naive IL-1alpha- or IL-1beta-deficient mice were subjected to Th2 polarization in vitro, they failed to polarize in the presence of IL-4 alone, but required the addition of exogenous IL-1alpha or IL-1beta. Furthermore, we demonstrate that both IL-1alpha- and IL-1beta-deficient mice are susceptible to chronic T. muris infection and that the inability to expel the worms is associated with a defect in the development of a Th2 response in the mesenteric lymph nodes. These results provide the first demonstration of the critical role of IL-1 in regulating Th2 responses during gastrointestinal nematode infection.     

The zinc finger DNA-binding domain of K-RBP plays an important role in regulating Kaposi's sarcoma-associated herpesvirus RTA-mediated gene expression

K-RBP is a KRAB-containing zinc finger protein with multiple zinc finger motifs and represses Kaposi's sarcoma-associated herpesvirus (KSHV) transactivator RTA-mediated transactivation of several viral lytic gene promoters, including the ORF57 promoter. Whether K-RBP binds DNA through its zinc fingers and the role of zinc finger domain in repressing gene expression are unclear. Here we report that K-RBP binds DNA through its zinc finger domain and the target DNA sequences contain high GC content. Furthermore, K-RBP binds to KSHV ORF57 promoter, which contains a GC-rich motif. K-RBP suppresses the basal ORF57 promoter activity as well as RTA-mediated activation. The zinc finger domain of K-RBP is sufficient for the suppression of ORF57 promoter activation mediated by the viral transactivator RTA. Finally, we show that K-RBP inhibits RTA binding to ORF57 promoter. These findings suggest that the DNA-binding activity of K-RBP plays an important role in repressing viral promoter activity.     

转录因子Ets-1对P21WAF1/CIP1启动子的影响

目的：研究转录因子Ets-1对P21WAF1/CIP1启动子的调控作用。 方法:应用瞬时转染、荧光素酶活性测定的方法分析Ets-1对P21WAF1/CIP1启动子荧光素酶报告重组体活性的影响。 结果:荧光素酶活性测定发现Ets-1可以上调P21WAF1/CIP1转录。缺乏激活结构域的Ets-1不能激活P21WAF1/CIP1启动子。Ets-1选择性地作用于P21WAF1/CIP1启动子中-1350GGAA-1347 Ets元件，该元件的序列突变可降低基础表达和Ets-1诱导的P21WAF1/CIP1启动子依赖的表达。-1577GGAT-1574元件介导基础表达，但不介导Ets-1激活的P21WAF1/CIP1启动子依赖的表达。 结论:Ets-1通过-1350GGAA-1347元件调控P21WAF1/CIP1启动子转录。     

核转录因子NF-κＢ参与单磷酰脂A预处理的延迟保护作用

目的：探讨核转录因子NF-κB在单磷酰脂A预处理的延迟阶段的作用。 方法： 建立大鼠心肌缺血/再灌注（I/R）损伤模型。分别应用单磷酰脂A（MLA）、NF-κB的特异性抑制剂DDTC加MLA预处理心脏, 24 h对心脏进行较长时间缺血再灌注，检测心肌梗死范围、LDH释放及心肌细胞凋亡率。另外分组检测MLA预处理0 min、15 min、30 min、60 min、NF-κB抑制剂DDTC加MLA预处理后30 min时NF-κB活性。 结果: MLA预处理减小再灌注心肌梗死范围、降低血浆LDH活性、减少细胞凋亡(P<0.05 vs I/R)。同MLA预处理组相比， DDTC+MLA组心肌梗死范围增大、LDH活性增高, 细胞凋亡增加(P<0.05)。与预处理前相比，NF-κB活性在预处理后15 min明显升高、30 min达到高峰、60 min下降(P<0.01)。与MLA预处理后15 min、30 min、60 min相比， DDTC加MLA预处理后30 min时,NF-κB活性明显降低(P<0.01)，而与MLA预处理0 min无显著差别(P＞0.05)。 结论: (1) MLA预处理对24 h后缺血/再灌注心肌有保护作用。(2) 核转录因子NF-κB参与心肌预处理后的延迟保护作用，MLA预处理后NF-κB快速的核转移并激活可能是药物预处理延迟保护作用的重要机制之一。     

胰岛素样生长因子-1通过细胞外信号调节激酶1/2通路下调转录因子基本转录元件结合蛋白表达抗心肌细胞凋亡

目的 探讨胰岛素样生长因子-1(IGF-1)对大鼠心肌细胞凋亡保护作用的基因调控机制。方法 体外培养新生大鼠心肌细胞,10nmol/L IGF-1刺激的同时,分别加入磷脂酰肌醇-3激酶（PI3K）、细胞外信号调节激酶（ERK）1/2和Raf-1 3条通路抑制剂（20μmol/L）,通过RT-PCR及Western blotting方法观察IGF-1调节基本转录元件结合蛋白（BTEB）的基因表达及其通路调控。100μmol/L H2O2处理诱导心肌细胞凋亡,通过DNA梯度分析、Annexin V-FITC/PI双染色法、Caspase-3活性测定、Hoechest33258染色法观察用BTEB特异性siRNA人为下调BTEB基因表达后对心肌细胞凋亡的影响。结果 大鼠心肌细胞经IGF-1刺激60min后,BTEB mRNA和蛋白表达均明显下降;与对照组相比,加入ERK1/2通路抑制剂PD98059组BTEB的mRNA和蛋白表达均明显增高（P＜0.01）;H2O2诱导的大鼠心肌细胞于下调BTEB表达后,DNA片段化改善,心肌细胞凋亡率下降（P＜0.05）,Caspase-3活性降低（P＜0.05）,凋亡小体减少,与IGF-1的抗心肌细胞凋亡效果相似。
结论 IGF-1可以通过ERK1/2通路下调转录因子BTEB基因表达而发挥抗心肌细胞凋亡的作用。