ArgD of Mycobacterium tuberculosis is a functional N-acetylornithine aminotransferase with moonlighting function as an effective immune modulator

Mycobacterium tuberculosis (M. tuberculosis) encodes an essential enzyme acetyl ornithine aminotransferase ArgD (Rv1655) of arginine biosynthetic pathway which plays crucial role in M. tuberculosis growth and survival. ArgD catalyzes the reversible conversion of N-acetylornithine and 2 oxoglutarate into glutamate-5-semialdehyde and L-glutamate. It also possesses succinyl diaminopimelate aminotransferase activity and can thus carry out the corresponding step in lysine biosynthesis. These essential roles played by ArgD in amino acid biosynthetic pathways highlight it as an important metabolic chokepoint thus an important drug target. We showed that M. tuberculosis ArgD rescues the growth of ΔargD E. coli grown in minimal media validating its functional importance. Phylogenetic analysis of M. tuberculosis ArgD showed homology with proteins in gram positive bacteria, pathogenic and non-pathogenic mycobacteria suggesting the essentiality of this protein. ArgD is a secretory protein that could be utilized by M. tuberculosis to modulate host innate immunity as its moonlighting function. In-silico analysis predicted it to be a highly antigenic protein. The recombinant ArgD protein when exposed to macrophage cells induced enhanced production of pro-inflammatory cytokines TNF, IL6 and IL12 in a dose dependent manner. ArgD also induced the increased production of innate immune effector molecule NOS2 and NO in macrophages. We also demonstrated ArgD mediated activation of the canonical NFkB pathway. Notably, we also show that ArgD is a specific TLR4 agonist involved in the activation of pro-inflammatory signaling for sustained production of effector cytokines. Intriguingly, ArgD protein treatment activated macrophages to acquire the M1 phenotype through the increased surface expression of MHCII and costimulatory molecules CD80 and CD86. ArgD induced robust B-cell response in immunized mice, validating its antigenicity potential as predicted by the in-silico analysis. These properties of M. tuberculosis ArgD signify its functional plasticity that could be exploited as a possible drug target to combat tuberculosis.     

BMP/TGF-β signaling as a modulator of neurodegeneration in ALS

This commentary focuses on the emerging intersection between BMP/TGF-β signaling roles in nervous system function and the amyotrophic lateral sclerosis (ALS) disease state. Future research is critical to elucidate the molecular underpinnings of this intersection of the cellular processes disrupted in ALS and those influenced by BMP/TGF-β signaling, including synapse structure, neurotransmission, plasticity, and neuroinflammation. Such knowledge promises to inform us of ideal entry points for the targeted modulation of dysfunctional cellular processes in an effort to abrogate ALS pathologies. It is likely that different interventions are required, either at discrete points in disease progression, or across multiple dysfunctional processes which together lead to motor neuron degeneration and death. We discuss the challenging, but intriguing idea that modulation of the pleiotropic nature of BMP/TGF-β signaling could be advantageous, as a way to simultaneously treat defects in more than one cell process across different forms of ALS.     

中药对癫痫相关信号通路调控作用的研究进展

癫痫是一种常见的神经系统疾病，其反复发作，迁延难愈，对患者的身心造成极大危害。抗癫痫药带来良好的治疗作用的同时也伴发着诸多身心损伤的不良反应。中医药治疗癫痫由来已久，目前除不断丰富传统中医理论治疗癫痫的认知理论外，从分子生物学角度研究中医药治疗癫痫的细胞信号传导机制发展迅速。通过对国内外文献检索发现，癫痫发生与细胞增殖、凋亡、自噬、炎症反应、免疫应答等病理生理过程密切相关；同时中西药的现代医学研究表明，无论是中药单体、单味中药甚至中药复方治疗癫痫的机制的研究均与文中所述信号通路有着直接或间接的关系，其可以通过调控相应信号通路的关键分子表达，达到抑制癫痫发生，控制癫痫发作，保护癫痫脑损伤的作用。该文通过对国内外研究现状进行总结，具体如下：①桔皮素，银杏内酯B等能通过激活磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/Akt）信号通路，抑制凋亡及氧化应激反应。②黄芩苷，蛇床子素等能通过抑制哺乳动物-雷帕霉素靶蛋白（mTOR）信号通路，抑制自噬。③灵芝多糖，黄芪甲苷等能通过抑制丝裂原活化蛋白激酶（MAPK）信号通路，减少细胞凋亡。④红景天苷，白藜芦醇等能通过激活核因子E2相关因子2/抗氧化反应元件/血红素加氧酶1（Nrf2/ARE/HO-1）信号通路，抗氧化应激反应及抑制凋亡。⑤姜黄素，黄芩苷等能通过抑制核转录因子-κB（NF-κB）信号通路，降低炎症反应及减少凋亡。以上总结旨在为中药治疗癫痫的深入研究提供参考依据，也为临床中药治疗癫痫提供新的思路。     

基于网络药理学联合GEO芯片分析百合乌药汤治疗胃癌的分子靶点及作用机制

目的:基于网络药理学联合GEO芯片差异基因分析的方法,分析百合乌药汤治疗胃癌的分子靶点和作用机制。方法:在TCMSP数据库检索中药药物信息,获得百合乌药汤的活性成分和分子靶点。在GEO芯片数据库通过检索"gastric cancer"分析筛选后获得GSE118916芯片数据,通过R软件分析得出差异基因,并绘制热图和火山图。通过Cytoscape3.7.2构建百合乌药汤与胃癌的成分-靶点网络图,使用插件Bisogenet和CytoNCA绘制核心靶点拓扑网络,并进行药物与疾病基因的GO富集分析(BP、CC、MF)和KEGG富集分析。结果:从GEO数据库下载分析得到与胃癌上调和下调最明显的差异基因40个。获得百合乌药汤有效活性成分10个,主要包括槲皮素(quercetin)、谷固醇(beta-sitosterol)、异松脂酸(Isopimaric acid)等,作用于PTGS2、ADH1C、ADRB2、PLAU、MAOA、CHRM3、CCNA2、MMP9、IL6等31个基因靶点。生物功能和通路富集分析表明,百合乌药汤治疗胃癌主要涉及脂多糖、氧化应激、血红素结合、蛋白激酶调节等方面,通过调节AGE-RAGE、TNF、NF-κB、IL17等信号通路发挥治疗作用。结论:百合乌药汤治疗胃癌的重要活性成分为槲皮素、谷固醇等,涉及TNF、NF-κB、IL17等信号通路。     

异牡荆素对非小细胞性肺癌细胞自我更新和凋亡的影响

目的研究异牡荆素(ISO)对非小细胞性肺癌(NSCLC)细胞的影响和潜在的机制。方法将A549和H1650细胞分别分为空白组、低剂量实验组(4μmol·L^-1 ISO)和高剂量实验组(16μmol·L^-1 ISO)。用噻唑蓝法检测NSCLC细胞活性,用肿瘤球形成实验检测NSCLC细胞的细胞球形成率,用Western blot法检测NSCLC细胞凋亡、自我更新、无翅型MMTV整合位点家族/β-连环蛋白(Wnt/β-catenin)信号通路相关蛋白的表达水平。结果与空白组比较,低、高剂量实验组中A549和H1650细胞在24,48和72 h的细胞活性均显著降低。低、高剂量实验组和空白组中A549细胞的细胞球形成率分别为(4.18±0.45)%,(2.01±0.67)%和(6.02±0.57)%,切割的半胱氨酸蛋白酶-3相对表达量分别为0.24±0.08,1.25±0.13和0.06±0.07,SRY相关高迁移率族盒蛋白-2相对表达量分别为0.49±0.04,0.25±0.03和1.00±0.09,Kruppel样因子4相对表达量分别为0.68±0.04,0.44±0.03和1.01±0.06,Wnt1相对表达量分别为0.63±0.06,0.28±0.04和1.00±0.06,β-catenin相对表达量分别为0.41±0.05,0.22±0.03和1.01±0.09;与空白组比较,低、高剂量实验组中A549细胞的上述指标的差异均有统计学意义(P<0.05,P<0.01)。上述3组中H1650细胞的上述指标也呈现一致的现象。结论ISO可能通过抑制Wnt/β-catenin信号通路来抑制NSCLC细胞活性和自我更新,并促进其凋亡。     

昆虫抗菌肽抗炎活性及基于信号通路抗炎机制的研究进展

昆虫抗菌肽是昆虫为抵御外界病原微生物感染产生的免疫活性物质的总称,其优异的抗炎活性使其具有广阔的应用前景。综述了不同种类昆虫抗菌肽的抗炎活性及可能涉及的信号通路,介绍了昆虫抗菌肽临床研究现状,以期为昆虫抗菌肽的应用研究提供文献参考。