A case of sudden cardiac death due to mitochondrial disease

A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.     

COX20基因变异线粒体复合物Ⅳ缺乏症相关的遗传性周围神经病4例病例系列报告及文献复习

背景：原发性线粒体病具有高度的临床和遗传异质性，其中周围神经是线粒体病的常见受累器官之一。 目的：总结COX20基因变异相关周围神经病的临床表型及遗传学特征。 设计：病例系列报告。 方法：回顾性收集2018年5月至2020年5月复旦大学附属儿科医院诊治的COX20基因变异相关周围神经病患儿的临床资料，总结其临床表现、基因检测结果及治疗效果，并以“COX20”、“线粒体复合物Ⅳ缺乏症（Complex Ⅳ deficiency）”为关键词检索中英文数据库。检索时间均为从建库至2021年12月。总结已报道COX20基因变异与临床表型的关系。 主要结局指标：临床表型和COX20基因变异位点。 结果：4例患儿纳入分析，男、女各2例，其中3例自幼运动发育落后。4例均在儿童期起病，均以行走不稳为首发症状。肌电图均提示多发性周围神经损害改变，感觉神经轴索受累为主。4例患儿均携带COX20基因复合杂合变异，包括错义变异2个，无义变异和移码变异各1个，其中移码变异c.262delG(p.E88Kfs*35)尚未见报道。文献复习目前共报道COX基因变异18个家系22例患儿（包括本文病例）,起病中位年龄为5（1.0~17）岁，22例均以行走困难或步态不稳起病，11例（50.0%）有精神运动发育迟滞，病程中14例(63.6%)出现构音障碍，14例(63.6%)出现肌力下降和/或足部畸形，8例（36.4%）出现共济失调，6例(27.3%)出现肌张力障碍，5例（22.7%）存在认知倒退等。21例患儿行神经传导及肌电图检查，19例(90.5%)提示多发性周围神经病变。头颅（18例）及脊髓（10例）MR检查提示，脊髓萎缩4例（40%），小脑萎缩4例（22.2%）。9例患儿已无法独立行走，丧失独立行走能力中位年龄为10（7~21）岁。目前共报道9个变异位点，4种变异类型，其中错义变异5个，剪切变异2个，无义变异和移码变异各1个。 结论：COX20基因变异患者多早期起病，以周围神经系统病变为主要表现，可合并构音障碍、共济失调、肌张力障碍、认知倒退等，病情逐渐进展，致残率高。COX20基因变异类型以错义变异最常见。     

Inhibition of autophagy enhances apoptosis induced by bortezomib in AML cells

Bortezomib is a novel proteasome inhibitor, which has been successfully used to treat mantle cell lymphoma and multiple myeloma. However, the direct effects of bortezomib on acute promyelocytic leukaemia (APL) have not been fully investigated. In the present study, the WST-8 assay, western blotting, flow cytometry, monodansylcadaverine staining and transmission electron microscopy were performed. It was demonstrated that bortezomib treatment induced a time- and dose-dependent decrease in the viability of NB4 cells. Bortezomib treatment induced cell apoptosis in NB4 cells, as assessed by Annexin V/propidium iodide analysis, and the detection of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, Bax and Bcl-2 expression. Furthermore, bortezomib treatment induced autophagy in NB4 cells, as indicated by autophagosome formation, p62 degradation, LC3-I to LC3-II conversion and formation of acidic autophagic vacuoles. Notably, autophagy induced by bortezomib was initiated prior to apoptosis. Inhibition of autophagy by knocking down Beclin-1 expression increased bortezomib-induced apoptosis in NB4 cells. Therefore, the present study revealed that the combination of bortezomib and autophagy inhibition may be a potential treatment strategy for APL.     

Pharmacological doses of melatonin impede cognitive decline in tau‐related Alzheimer models,once tauopathy is initiated,by restoring the autophagic flux

Alterations in autophagy are increasingly being recognized in the pathogenesis of proteinopathies like Alzheimer's disease (AD). This study was conducted to evaluate whether melatonin treatment could provide beneficial effects in an Alzheimer model related to tauopathy by improving the autophagic flux and, thereby, prevent cognitive decline. The injection of AAV‐hTau^P301L viral vectors and treatment/injection with okadaic acid were used to achieve mouse and human ex vivo, and in vivo tau‐related models. Melatonin (10 μmol/L) impeded oxidative stress, tau hyperphosphorylation, and cell death by restoring autophagy flux in the ex vivo models. In the in vivo studies, intracerebroventricular injection of AAV‐hTau^P301L increased oxidative stress, neuroinflammation, and tau hyperphosphorylation in the hippocampus 7 days after the injection, without inducing cognitive impairment; however, when animals were maintained for 28 days, cognitive decline was apparent. Interestingly, late melatonin treatment (10 mg/kg), starting once the alterations mentioned above were established (from day 7 to day 28), reduced oxidative stress, neuroinflammation, tau hyperphosphorylation, and caspase‐3 activation; these observations correlated with restoration of the autophagy flux and memory improvement. This study highlights the importance of autophagic dysregulation in tauopathy and how administration of pharmacological doses of melatonin, once tauopathy is initiated, can restore the autophagy flux, reduce proteinopathy, and prevent cognitive decline. We therefore propose exogenous melatonin supplementation or the development of melatonin derivatives to improve autophagy flux for the treatment of proteinopathies like AD.     

高压氧治疗对局灶性脑梗死大鼠的神经保护作用

目的 观察单次9 h高压氧（hyp erbaric oxygen，HBO）治疗对局灶性脑梗死大鼠凋亡诱导因子 （apoptosis-inducing factor，AIF）、线粒体膜电位（mitochondrial membrane potential，MMPo）的影响，探讨 HBO治疗的神经保护作用。 方法 108只SD大鼠制作永久性大脑中动脉闭塞模型，随机分为对照组和HBO组，每组各54只。造 模成功3 h后，HBO组实行HBO干预，压力0.2 MPa持续9 h，对照组呼吸常压空气。采用Garcia评分评估 大鼠神经功能，比较两组造模后13 h、24 h和72 h神经功能改善情况，并在各时间点检测大鼠缺血半 暗带脑组织凋亡细胞数、线粒体和细胞核AIF表达及MMPo水平。 结果 ①神经功能评分：HBO组13 h（P <0.001）、24 h（P =0.04）神经功能评分改善比对照组更明显。 ②凋亡细胞数：HBO组13 h、24 h凋亡细胞数较对照组更少（均P <0.001）。③AIF在线粒体和细胞核的 表达：13 h、24 h、72 h各时间点HBO组AI F在线粒体的表达均较对照组多（均P <0.001）；各时间点HBO 组AIF在细胞核的表达均较对照组少（均P <0.001）。④MMPo：各时间点HBO组MMPo均高于对照组（均 P <0.001）。 结论 HBO治疗可改善大鼠神经功能，稳定MMPo，抑制AIF由线粒体向细胞核转移可能是其神经保 护作用的机制之一。     

基于“通肾络、益脾肾”治法研究足细胞凋亡及自噬

[目的]基于中医"通肾络、益脾肾"治法,探讨通络益肾方对体外高糖培养的小鼠肾小球足细胞自噬和凋亡蛋白SIRT1、BNIP3、P62、Bax表达的调控影响。[方法]成熟无特定病原体(SPF)级SD雄性大鼠40只,随机分为正常组、中药高、中、低剂量组各10只。按照人与大鼠体表面积折算方法计算出大鼠所需中药灌胃浓度:高剂量浓度4.76 g/mL、中剂量浓度2.38 g/mL、低剂量浓度1.19 g/m L,灌胃10 d取含药血清备用。足细胞分6组,正常组5.6 mmol/L葡萄糖+10%正常大鼠血清、高糖组30mmol/L葡萄糖+10%正常大鼠血清、通络益肾方含药血清高、中、低干预组30 mmol/L葡萄糖+10%高、中、低剂量大鼠血清、高渗组甘露醇24.5 mmol/L+10%正常大鼠血清。细胞培养48 h后收集,Hoechst33342荧光染色,观察各组足细胞凋亡状况及形态变化;流式细胞仪检测足细胞凋亡率;Western Blot检测细胞内自噬标志蛋白SIRT1、P62及促凋亡蛋白BNIP3、Bax表达水平。[结果]流式细胞仪检测结果显示通络益肾方中、低剂量组可降低高糖诱导的足细胞凋亡率(P0.01或P0.05),高剂量组不能改善凋亡情况(P0.05);Hoechst33342荧光染色观察结果也证实通络益肾方中、低剂量组可降低高糖诱导的足细胞凋亡率;蛋白印迹结果显示,与高糖组相比,通络益肾方中、低剂量组自噬标志蛋白SIRT1表达升高,自噬标志蛋白P62及促凋亡蛋白BNIP3、Bax蛋白表达下降(P0.05或P0.01),高剂量组SIRT1、BNIP3、P62、Bax蛋白表达未见明显改变(P0.05)。[结论]中剂量、低剂量通络益肾方能够启动细胞自噬减少高糖刺激下体外培养足细胞凋亡,降低细胞凋亡率及凋亡蛋白的表达。     

Survivin-shRNA对视网膜母细胞瘤HXO-RB44细胞自噬及凋亡的影响

目的:研究Survivin-shRNA对视网膜母细胞瘤HXO-RB44细胞自噬及凋亡的影响。方法:培养视网膜母细胞瘤HXO-RB44细胞，构建Survivin-shRNA载体。按照处理不同分为Survivin-shRNA组、GFP组和CON组。分别采用流式细胞术检测Survivin-shRNA对HXO-RB44细胞凋亡和细胞周期的影响，应用MTT法检测Survivin-shRNA对HXO-RB44细胞活性的影响，Western blot法检测Survivin-shRNA对HXO-RB44 细胞自噬相关蛋白LC3、p62 与mTOR 表达的影响。结果:流式细胞术结果表明，与Control组和GFP组相比，Survivin-shRNA组细胞凋亡率增加，差异有统计学意义（P＜0.05）；随着作用时间的延长，S期出现阻滞，48 h阻滞最强，显著高于对照组（P＜0.05）。MTT结果发现Survivin-shRNA可抑制HXO-RB44细胞增殖活性，与Control组和GFP组相比，差异有统计学意义（P＜0.05）；Western blot结果发现，与对照组相比，LC3表达量显著增加（P＜0.01）；而mTOR表达量降低（P＜0.01）。结论:Survivin-shRNA可促进视网膜母细胞瘤HXO-RB44细胞的凋亡和自噬水平，进而特异性杀伤肿瘤细胞。     

自噬在前列腺癌发生发展和治疗中的研究进展

自噬是真核细胞通过溶酶体对其自身生物大分子和细胞器回收再利用的过程，其在维持细胞稳态中发挥重要作用，并参与多种病理生理过程。在肿瘤的发病过程中，自噬发挥“双面作用”，既可以抗癌也能促癌。前列腺癌是老年男性最常见的恶性肿瘤，研究表明前列腺癌的发生发展与自噬作用密切相关，放化疗、内分泌治疗等对肿瘤细胞造成的应激可通过自噬得以缓解，抵抗治疗，因而自噬抑制剂对于放化疗等具有协同促进作用。本文就自噬在前列腺癌中发病和治疗进行综述，以期为前列腺癌的诊治提供一些新的思路。     

高乳酸血症-卒中样发作综合征型线粒体脑肌病一家系两代四例报告

线粒体脑肌病属于罕见性母系遗传病，本文回顾性分析了1家4例高乳酸血症-卒中样发作综合征（MELAS）型线粒体脑肌病患者，其主要表现为卒中样发作、头痛、癫痫、高乳酸血症、肌肉不耐受疲劳、高级智能下降、听力下降和身材矮小等，结合特征性影像学变化、基因检测及肌肉活检明确诊断，并结合文献对只有女儿能将其线粒体DNA（mt-DNA）传递给下一代的母系遗传MELAS型线粒体脑肌病临床特点进行了总结分析，旨在帮助临床认识此病，进一步提高MELAS型线粒体脑肌病的临床诊断率。