TDP-43 Toxicity in Yeast Is Associated with a Reduction in Autophagy,and Deletions of TIP41 and PBP1 Counteract These Effects

When human TDP-43 is overexpressed in yeast it is toxic and forms cytoplasmic aggregates. The mechanism of this toxicity is unknown. Genetic screens for TDP-43 toxicity modifiers in the yeast system previously identified proteins, including PBP1, that enhance TDP-43 toxicity. The determination in yeast that deletion of PBP1 reduces TDP-43 toxicity while overexpression enhances toxicity, led to the discovery that its human homolog, ATXN2, is associated with ALS risk. Thus, the yeast system has relevance to human disease. We now show that deletion of a new yeast gene, tip41Δ, likewise suppresses TDP-43 toxicity. We also found that TDP-43 overexpression and toxicity is associated with reduced autophagy. This is consistent with findings in other systems that increasing autophagy reduces TDP-43 toxicity and is in contrast to a report of enhanced autophagy when TDP-43 was overexpressed in yeast. Interestingly, we found that deletions of PBP1 and TIP41, which reduced TDP-43 toxicity, eliminated TDP-43′s inhibition of autophagy. This suggests that toxicity of TDP-43 expressed in yeast is in part due to its inhibition of autophagy and that deletions of PBP1 and TIP41 may reduce TDP-43 toxicity by preventing TDP-43 from inhibiting autophagy.     

Ganoderma lucidum Modulates Inflammatory Responses following 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP) Administration in Mice

Ganoderma lucidum, one of the most valued medicinal mushrooms, has been used for health supplements and medicine in China. Our previous studies have proved that Ganoderma lucidum extract (GLE) could inhibit activation of microglia and protect dopaminergic neurons in vitro. In the present study, we investigated the anti-neuroinflammatory potential of GLE in vivo on Parkinsonian-like pathological dysfunction. Male C57BL/6J mice were subjected to acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesion, and a treatment group was administered intragastrically with GLE at a dose of 400 mg/kg. Immunohistochemistry staining showed that GLE efficiently repressed MPTP-induced microglia activation in nigrostriatal region. Accordingly, Bio-plex multiple cytokine assay indicated that GLE treatment modulates abnormal cytokine expression levels. In microglia BV-2 cells incubated with LPS, increased expression of iNOS and NLRP3 were effectively inhibited by 800 μg/mL GLE. Furthermore, GLE treatment decreased the expression of LC3II/I, and further enhanced the expression of P62. These results indicated that the neuroprotection of GLE in an experimental model of PD was partially related to inhibition of microglia activation in vivo and vitro, possibly through downregulating the iNOS/NLRP3 pathway, inhibiting abnormal microglial autophagy and lysosomal degradation, which provides new evidence for Ganoderma lucidum in PD treatment.     

8-氮鸟嘌呤通过Akt/mTORC1/ULK1诱导细胞自噬增强其在肝癌细胞中的耐药性

细胞自噬是真核生物中进化保守的对细胞内容物进行降解的生理过程,其利用溶酶体将细胞内物质降解再利用,在应激条件下可以促进癌细胞的存活.8-氮鸟嘌呤(8-azaguanine,8-AG)是一种嘌呤核苷酸生物合成的抑制剂,对多种肿瘤细胞具有抗肿瘤活性.然而,耐药性限制了8-AG作为抗癌药物的应用,其耐药性机制尚不清楚.本研究...     

Zearalenone Induces Apoptosis in Porcine Endometrial Stromal Cells through JNK Signaling Pathway Based on Endoplasmic Reticulum Stress

Zearalenone (ZEA) is an estrogen-like mycotoxin characterized mainly by reproductive toxicity, to which pigs are particularly sensitive. The aim of this study was to investigate the molecular mechanism of ZEA-induced apoptosis in porcine endometrial stromal cells (ESCs) by activating the JNK signaling pathway through endoplasmic reticulum stress (ERS). In this study, ESCs were exposed to ZEA, with the ERS inhibitor sodium 4-Phenylbutyrate (4-PBA) as a reference. The results showed that ZEA could damage cell structures, induce endoplasmic reticulum swelling and fragmentation, and decreased the ratio of live cells to dead cells significantly. In addition, ZEA could increase reactive oxygen species and Ca²⁺ levels; upregulate the expression of GRP78, CHOP, PERK, ASK1 and JNK; activate JNK phosphorylation and its high expression in the nucleus; upregulate the expression Caspase 3 and Caspase 9; and increase the Bax/Bcl-2 ratio, resulting in increased apoptosis. After 3 h of 4-PBA-pretreatment, ZEA was added for mixed culture, which showed that the inhibition of ERS could reduce the cytotoxicity of ZEA toward ESCs. Compared with the ZEA group, ERS inhibition increased cell viability; downregulated the expression of GRP78, CHOP, PERK, ASK1 and JNK; and decreased the nuclear level of p-JNK. The Bax/Bcl-2 ratio and the expression of Caspase 3 and Caspase 9 were downregulated, significantly alleviating apoptosis. These results demonstrate that ZEA can alter the morphology of ESCs, destroy their ultrastructure, and activate the JNK signaling via the ERS pathway, leading to apoptosis.     

CHOP在索拉菲尼联合辛二酰苯胺异羟肟酸诱导人肝癌细胞MHCC97L凋亡中的作用

目的:探讨CCAAT/增强子结合蛋白同源蛋白(CHOP)在索拉菲尼联合辛二酰苯胺异羟肟酸(SAHA)诱导人肝癌细胞MHCC97L凋亡中的作用。方法:采用CCK-8法检测索拉菲尼联合SAHA对MHCC97L细胞活力的影响;采用流式细胞术检测索拉菲尼联合SAHA对细胞周期及细胞凋亡的影响;应用Western blot法检测索拉菲尼联合SAHA对MHCC97L细胞中内质网应激相关分子葡萄糖调节蛋白78(GRP78)、蛋白激酶R样内质网激酶(PERK)、p-PERK、活化转录因子4(ATF4)及CHOP蛋白表达的影响。此外,应用CHOP siRNA沉默CHOP后,采用流式细胞术观察索拉菲尼联合SAHA对MHCC97L细胞凋亡的影响。结果:索拉菲尼联合SAHA可使MHCC97L细胞活力明显下降(P<0.05),细胞周期结果显示细胞生长被阻滞在G₁期; Western blot结果显示索拉菲尼联合SAHA可显著上调上述内质网应激凋亡通路中相关蛋白的表达,同时流式细胞术检测发现索拉菲尼联合SAHA可显著促进MHCC97L细胞凋亡(P<0.01);CHOP siRNA...     

AMPK通过抑制NLRP3炎症小体参与延缓衰老过程

<正>衰老是在细胞、组织和器官水平上发生的生理性内稳态的渐进性损害过程。就代谢角度而言,该过程主要表现为体成分、胰岛素抵抗、自噬功能障碍、线粒体和炎症反应的变化,其中涉及生长激素、胰岛素/胰岛素样生长因子1及各种能量感应系统如AMP活化蛋白激酶(AMP-activated protein kinase,AMPK)、沉默信息调节因子(silent information regula‐tors,SIRTs)等多条信号通路的变化^[1]。而从临床角     

胰岛素抵抗的发病机制研究进展

胰岛素抵抗是一种由遗传和环境因素引起的胰岛素促进葡萄糖摄取和利用率下降,机体对胰岛素生理作用反应性、敏感性降低的一种病理状态,主要作用于肝脏、脂肪、肌肉组织,由此引起的糖、脂代谢紊乱可导致糖尿病、冠心病、肥胖症、代谢综合征等多种代谢紊乱性疾病。近年来,相关研究表明脂肪细胞因子、炎症反应、NF-κB非依赖机制、线粒体功能障碍、内质网应激等与胰岛素抵抗密切相关。     

川芎嗪通过抑制内质网应激减轻小肠缺血再灌注损伤的研究

目的 研究川芎嗪(TMP)对大鼠小肠缺血再灌注损伤及内质网应激通路的影响.方法 将120只Wistar大鼠按照随机数字表法平均分为假手术组、模型组和TMP低、中、高(15、30、60 mg/kg)剂量组.造模前30 min腹腔注射给药,假手术组、模型组腹腔注射生理盐水.通过夹闭肠系膜上动脉60 min制备小肠缺血再灌注...     

Histone deacetylase inhibitors inhibit cervical cancer growth through Parkin acetylation-mediated mitophagy

Parkin, an E3 ubiquitin ligase, plays a role in maintaining mitochondrial homeostasis through targeting damaged mitochondria for mitophagy. Accumulating evidence suggests that the acetylation modification of the key mitophagy machinery influences mitophagy level, but the underlying mechanism is poorly understood. Here, our study demonstrated that inhibition of histone deacetylase (HDAC) by treatment of HDACis activates mitophagy through mediating Parkin acetylation, leading to inhibition of cervical cancer cell proliferation. Bioinformatics analysis shows that Parkin expression is inversely correlated with HDAC2 expression in human cervical cancer, indicating the low acetylation level of Parkin. Using mass spectrometry, Parkin is identified to interact with two upstream molecules, acetylase acetyl-CoA acetyltransferase 1 (ACAT1) and deacetylase HDAC2. Under treatment of suberoylanilide hydroxamic acid (SAHA), Parkin is acetylated at lysine residues 129, 220 and 349, located in different domains of Parkin protein. In in vitro experiments, combined mutation of Parkin largely attenuate the interaction of Parkin with PTEN induced putative kinase 1 (PINK1) and the function of Parkin in mitophagy induction and tumor suppression. In tumor xenografts, the expression of mutant Parkin impairs the tumor suppressive effect of Parkin and decreases the anticancer activity of SAHA. Our results reveal an acetylation-dependent regulatory mechanism governing Parkin in mitophagy and cervical carcinogenesis, which offers a new mitophagy modulation strategy for cancer therapy.