蚯蚓提取物对家蚕中肠氧化损伤、总抗氧化能力及抗氧化酶含量的影响

【目的】研究蚯蚓提取物对家蚕Bombyx mori中肠组织氧化应激及抗氧化酶含量的影响,探究蚯蚓提取物的抗氧化功能。【方法】分别给家蚕5龄幼虫饲喂蚯蚓(赤子爱胜蚓Eisenia foetida)提取液原液的50, 100和200倍稀释液处理后的桑叶,测定处理6 d后家蚕中肠组织中氧化损伤产物丙二醛(MDA)和乳酸脱氢酶(LDH)的含量;利用qRT-PCR检测家蚕中肠组织中抗氧化酶关键基因(Cat,Sod和GSH-Px)的mRNA表达水平;同时采用ELISA法检测中肠组织中抗氧化酶[过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)]含量及总抗氧化能力(T-AOC)。【结果】与对照组相比,50, 100和200倍稀释组家蚕中肠组织中MDA, CAT, SOD和GSH-Px含量及T-AOC均差异不显著,200倍稀释组LDH含量显著降低了9.85%,100倍稀释组中肠中Cat和GSH-Px的表达量均显著高于对照组,3个稀释组中Sod的表达量均显著高于对照组。【结论】添食蚯蚓提取物可通过降低家蚕中肠LDH含量、提高抗氧化酶基因的表达水平进而提高家蚕的抗氧化能力。     

A prognostic eight-gene expression signature for patients with breast cancer receiving adjuvant chemotherapy

Breast cancer is a popularly diagnosed malignant tumor. Genomic profiling studies suggest that breast cancer is a disease with heterogeneity. Chemotherapy is one of the chief means to treat breast cancer, while its responses and clinical outcomes vary largely due to the conventional clinicopathological factors and inherent chemosensitivity of breast cancer. Using the least absolute shrinkage and selection operator (LASSO) Cox regression model, our study established a multi-mRNA-based signature model and constructed a relative nomogram in predicting distant-recurrence-free survival for patients receiving surgery and following chemotherapy. We constructed a signature of eight mRNAs (IPCEF1, SYNDIG1, TIGIT, SPESP1, C2CD4A, CLCA2, RLN2, and CCL19) with the LASSO model, which was employed to separate subjects into groups with high- and low-risk scores. Obvious differences of distant-recurrence-free survival were found between these two groups. This eight-mRNA-based signature was independently associated with the prognosis and had better prognostic value than classical clinicopathologic factors according to multivariate Cox regression results. Receiver operating characteristic results demonstrated excellent performance in diagnosing 3-year distant-recurrence by the eight-mRNA signature. A nomogram that combined both the eight-mRNA-based signature and clinicopathological risk factors was constructed. Comparing with an ideal model, the nomograms worked well both in the training and validation sets. Through the results that the eight-mRNA signature effectively classified patients into low- and high-risk of distant recurrence, we concluded that this eight-mRNA-based signature played a promising predictive role in prognosis and could be clinically applied in breast cancer patients receiving adjuvant chemotherapy.     

miR-222 inhibits cardiac fibrosis in diabetic mice heart via regulating Wnt/β-catenin-mediated endothelium to mesenchymal transition

miR-222 participates in many cardiovascular diseases, but its effect on cardiac remodeling induced by diabetes is unclear. This study evaluated the functional role of miR-222 in cardiac fibrosis in diabetic mice. Streptozotocin (STZ) was used to establish a type 1 diabetic mouse model. After 10 weeks of STZ injection, mice were intravenously injected with Ad-miR-222 to induce the overexpression of miR-222. miR-222 overexpression reduced cardiac fibrosis and improved cardiac function in diabetic mice. Mechanistically, miR-222 inhibited the endothelium to mesenchymal transition (EndMT) in diabetic mouse hearts. Mouse heart fibroblasts and endothelial cells were isolated and cultured with high glucose (HG). An miR-222 mimic did not affect HG-induced fibroblast activation and function but did suppress the HG-induced EndMT process. The antagonism of miR-222 by antagomir inhibited HG-induced EndMT. miR-222 regulated the promoter region of β-catenin, thus negatively regulating the Wnt/β-catenin pathway, which was confirmed by β-catenin siRNA. Taken together, our results indicated that miR-222 inhibited cardiac fibrosis in diabetic mice via negatively regulating Wnt/β-catenin-mediated EndMT.     

MFN2 silencing promotes neural differentiation of embryonic stem cells via the Akt signaling pathway

Mitofusin 2 (MFN2) is a regulatory protein participating in mitochondria dynamics, cell proliferation, death, differentiation, and so on. This study aims at revealing the functional role of MFN2 in the pluripotency maintenance and primitive differetiation of embryonic stem cell (ESCs). A dox inducible silencing and routine overexpressing approach was used to downregulate and upregulate MFN2 expression, respectively. We have compared the morphology, cell proliferation, and expression level of pluripotent genes in various groups. We also used directed differentiation methods to test the differentiation capacity of various groups. The Akt signaling pathway was explored by the western blot assay. MFN2 upregulation in ESCs exhibited a typical cell morphology and similar cell proliferation, but decreased pluripotent gene markers. In addition, MFN2 overexpression inhibited ESCs differentiation into the mesendoderm, while MFN2 silencing ESCs exhibited a normal cell morphology, slower cell proliferation and elevated pluripotency markers. For differentiation, MFN2 silencing ESCs exhibited enhanced three germs' differentiation ability. Moreover, the protein levels of phosphorylated Akt308 and Akt473 decreased in MFN2 silenced ESCs, and recovered in the neural differentiation process. When treated with the Akt inhibitor, the neural differentiation capacity of the MFN2 silenced ESCs can reverse to a normal level. Taken together, the data indicated that the appropriate level of MFN2 expression is essential for pluripotency and differentiation capacity in ESCs. The increased neural differentiation ability by MFN2 silencing is strongly related to the Akt signaling pathway.     

A robust six-miRNA prognostic signature for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a major health problem worldwide. We aimed to identify a robust microRNA (miRNA)-based signature for predicting HNSCC prognosis. The miRNA expression profiles of HNSCC were obtained from The Cancer Genome Atlas (TCGA) database. The TCGA HNSCC cohort was randomly divided into the discovery and validation cohort. A miRNA-based prognostic signature was built up based on TGCA discovery cohort, and then further validated. The downstream targets of prognostic miRNAs were subjected to functional enrichment analyses. The role of miR-1229-3p, a prognosis-related miRNA, in tumorigenesis of HNSCC was further evaluated. A total of 305 significantly differentially expressed miRNAs were found between HNSCC samples and normal tissues. A six-miRNA prognostic signature was constructed, which exhibited a strong association with overall survival (OS) in the TCGA discovery cohort. In addition, these findings were successfully confirmed in TCGA validation cohort and our own independent cohort. The miRNA-based signature was demonstrated as an independent prognostic indicator for HNSCC. A risk signature-based nomogram model was constructed and showed good performance for predicting the OS for HNSCC. The functional analyses revealed that the downstream targets of these prognostic miRNAs were closely linked to cancer progression. Mechanistically, in vitro analysis revealed that miR-1229-3p played a tumor promoting role in HNSCC. In conclusion, our study has developed a robust miRNA-based signature for predicting the prognosis of HNSCC with high accuracy, which will contribute to improve the therapeutic outcome.     

NDM-1结构功能及抑制剂的抑制机理

在过去的10年中,以新德里金属β-内酰胺酶-1(NDM-1)为代表的金属β-内酰胺酶在全球范围内广泛传播,对公共卫生安全产生了较大的威胁。尤其是近些年这些酶的突变体的出现使得耐药菌给人类健康造成了更加复杂和困难的挑战。目前,临床上仍然缺乏有效的治疗药物和手段。研发有效广谱的抑制剂成为解决此问题的重点。因此本文将针对NDM-1及其相关抑制剂复合物的三维结构解析工作进行综述,希望从生物学机制研究的角度带给相关研究人员一点启发和帮助。     

猪源乳酸杆菌与益生元组合筛选及其体外发酵特性

【目的】对3株乳酸杆菌和4种寡糖类益生元进行组合筛选,并探究其对猪结肠微生物体外发酵特性的影响。【方法】将3株乳酸杆菌(罗伊氏乳杆菌L45、植物乳杆菌L47和罗伊氏乳杆菌L63)分别添加至以菊粉(inulin)、低聚果糖(FOS)、低聚半乳糖(GOS)或乳果糖(lactulose)为唯一碳源的培养基中,结合菌株24 h的生长活性和产酸特性,筛选出最优组合;进一步利用体外发酵技术探究所筛选合生元组合对微生物和发酵特性的影响。【结果】L45和L63分别以FOS和Lactulose为碳源发酵时的生长曲线与葡萄糖相似,L47发酵Inulin和FOS的ΔOD600显著高于葡萄糖(P<0.05),且L47发酵Inulin产生的乳酸是葡萄糖的1.20倍,L47+FOS和L47+Inulin组合效应较好。体外发酵结果表明,与对照组相比,L47+FOS和L47+Inulin降低了发酵液中螺旋体门(Spirochaetes)的相对丰度,提高了乳杆菌属(Lactobacillus)和双歧杆菌属(Bifidobacterium)的相对丰度;L47+Inulin和L47+FOS显著提高了总短链脂肪酸含量(P<0.05);与L47+Inulin组相比,L47+FOS组乙酸和丁酸含量更高(P<0.05)。【结论】L47+FOS与L47+Inulin具有较好的组合效应,且具有改善猪结肠体外发酵的能力,提示L47+FOS和L47+Inulin作为合生元的发展潜力,两种组合在体内情况的效果有待深入研究。     

CRISPR-Cas9技术在细菌耐药性防控研究进展

近年来,多种新型耐药基因的出现和全球性流行,严重威胁了全球公众健康。CRISPR-Cas9系统(clustered regularly interspaced short palindromic repeats-CRISPR associated protein 9 system)是细菌的一种适应性免疫系统,可切割耐药基因、抵御外来核酸入侵,现已作为一种新型基因编辑工具应用于防控细菌耐药性研究。本团队已建立了一种单质粒介导靶向mcr-1基因的CRISPR-Cas9系统,能有效并特异性消除黏菌素耐药大肠杆菌中的mcr-1,恢复其对黏菌素的敏感性。同时也发现在临床中应用还需要优化其递送方式。本文对近几年该技术在细菌耐药性防控方面的研究进展进行了综述,包括CRISPR-Cas9系统的发现过程、作用机制、递送方式、在体外检测实验结果的进展以及当前存在的问题等方面,以期为防控细菌耐药性提供新思路。     

Probiotic Bacillus amyloliquefaciens mediate M1 macrophage polarization in mouse bone marrow-derived macrophages

Depending on the microenvironment, macrophages can acquire distinct functional phenotypes, referred to as classically activated M1 and M2. M1 macrophages are considered potent effector cells that kill intracellular pathogens, and M2 macrophages promote the resolution of wound healing. In this study, we are interested to know whether probiotic Bacillus amyloliquefaciens (Ba) can induce macrophages polarization. Real-time fluorescence PCR analysis demonstrated that the expression of IL-1β, iNOS, TNF-α and IL-6 genes for M1 macrophages was significantly increased at 1.5 h after probiotic Ba treatment compared to the probiotic Ba-free treatment (P < 0.01), whereas the expression of M2 macrophage marker genes (Arg1, Fizz1, MR, Ym1) was decreased (P < 0.05). Furthermore, the phagocytic activity was dramatically increased in the Ba-treated BMDMs using a FITC-dextran endocytosis assay. Together, these findings indicated that probiotic Ba facilitated polarization of M1 macrophages and enhanced its phagocytic capacity. The results expanded our knowledge about probiotic function-involved macrophage polarization.