溶酶体在2,2’,4,4’-四溴联苯醚诱导HepG2细胞凋亡中的作用

[目的]探讨2,2’,4,4’-四溴联苯醚(BDE 47)致人肝癌HepG2细胞凋亡机制. [方法]不同浓度BDE 47(0.00、6.25、12.50、25.00、50.00、100.00 μmol/L)染毒HepG2细胞24h,采用四氮唑盐比色法(MTT法)检测细胞存活率;用2’,7’-二氢二氯荧光素(DCFH-DA)探针检测活性氧水平;用吖啶橙(AO)探针及罗丹明(Rh123)荧光探针分别检测溶酶体膜通透性和线粒体膜电势,并通过溶酶体组织蛋白酶B特异性抑制剂环氧酶琥珀酰肽甲基酯(CA-074)验证溶酶体在BDE 47细胞毒性的作用. [结果]与对照组比较,50.00、100.00 μmol/L BDE 47染毒组HepG2细胞存活率明显降低(P＜0.01);各BDE47染毒组HepG2细胞凋亡率明显升高(P＜0.01),呈现剂量-效应关系(R2=0.981);各BDE47染毒组HepG2细胞活性氧含量明显升高(P＜0.01),≥12.50μmol/L BDE 47染毒组HepG2细胞内溶酶体膜通透性明显升高(P＜0.05; P＜0.01),各BDE47染毒组HepG2细胞内线粒体膜电势明显降低(P＜0.01),上述3项指标与染毒浓度均呈剂量-效应关系(R2=0.918,R2=0.636,R2=0.678).25 μmol/L CA-074能够明显干预50 μmol/L BDE 47对细胞的毒性作用使细胞存活率升高,细胞调亡减少(均P＜0.05). [结论]BDE47可能通过溶酶体介导线粒体途径诱导HepG2细胞凋亡.     

Mechanisms of silver nanoparticle-induced toxicity and important role of autophagy

Safety concerns have been raised over the extensive applications of silver nanoparticles (AgNPs) because nano dimensions make them highly bioactive, being potentially harmful to the exposed humans. Surface physico-chemistry (shape, surface charge, chemical composition, etc.) that mainly dictates nano-bio interactions is relevant for influencing their biocompatibility and toxicity. Although the hazardousness of AgNPs has been demonstrated in vitro and in vivo, mechanistic understanding of the toxicity particularly at the molecular and organismal levels, in addition to oxidative stress and silver ion dissolution, has remained unclear. A growing body of research has elucidated that autophagy, being activated in response to exposure to various nanomaterials, may serve as a cellular defense mechanism against nanotoxicity. Recently, autophagy activation was shown to correlate with AgNPs exposure; however, the subsequent autophagosome–lysosome fusion was defective. As autophagy plays a crucial role in selective removal of stress-mediated protein aggregates and injured organelles, AgNPs-induced autophagic flux defect may consequently lead to aggravated cytotoxic responses. Furthermore, we suggest that p62 accumulation resulting from defective autophagy may also potentially account for AgNPs cytotoxicity. Intriguingly, AgNPs have been shown to interfere with ubiquitin modifications, either via upregulating levels of enzymes participating in ubiquitination, or through impairing the biological reactivity of ubiquitin (due to formation of AgNPs-ubiquitin corona). Ubiquitination both confers selectivity to autophagy as well as modulates stabilization, activation, and trafficking of proteins involved in autophagic clearance pathways. In this regard, we offer a new perspective that interference of AgNPs with ubiquitination may account for AgNPs-induced defective autophagy and cytotoxic effects.     

Elevated Bone Turnover in an Infantile Patient with Mucolipidosis II; No Association with Hyperparathyroidism

This present report concerns an infantile patient with mucolipidosis II, who showed transient cortical bone hyperostosis followed by severe osteopenia. The diagnosis of mucolipidosis II was made based on the leakage of lysosomal enzymes in serum and conditioned media of the patient''s skin fibroblasts, low activity of lysosomal enzymes of the fibroblasts and mutation of c.2086_2089insC (p.L697fs) and c.3565C>T (p.R1189X) in the GNPTAB gene. Bone X-ray analysis demonstrated a periosteal reaction and elevated bone resorption at the age of 2 mo. Bone markers, including alkaline phosphatase, osteocalcin and urine deoxypyridinoline, also indicated a high turnover of bone metabolism; however, no apparent rickets-like changes and no increased levels of PTH were observed. Elevated bone resorption is possibly associated with the leakage of lysosomal enzyme from osteoclasts into bone matrices. Bone formation gradually reduced, and increased bone resorption persisted. This led to severe osteopenia at the age of 6 mo. Characteristic bone findings may contribute to early diagnosis of mucolipidosis II, but their pathogenesis remains to be clarified.     

高温后巨噬细胞在ConA刺激下的变化

用激光扫描共焦显微镜观察了高温后大鼠腹腔巨噬细胞在刀豆素A刺激下的变化,结果显示：Ca^2 内流增强,促进巨噬细胞内吞;溶酶体内pH值上下波动加快,有利于溶酶体内容物外排及配体的结合,提高了溶酶体的工作效率。     

The Vicious Cycle Between α-Synuclein Aggregation and Autophagic-Lysosomal Dysfunction

The accumulation and misfolding of α-synuclein (α-syn) represent the main pathological hallmark of PD. Overexpression of α-syn and failure of cellular protein degradation systems play a major role in α-syn aggregation. The discovery of PD-associated genes related to the autophagic-lysosomal pathway, such as VPS35, LRRK2, GBA1, SMPD1, GALC, ASAH1, SCARB2, CTSD, CTSB, and GLA, confirms the involvement of cellular clearance systems dysfunction in PD pathogenesis. Of importance, lysosomal enzyme activity is altered both in genetic and sporadic PD. Decreased lysosomal enzymes activities were measured in the same brain regions where α-syn accumulates, suggesting that a crosstalk between α-syn aggregation and autophagic-lysosomal impairment may exist. The understanding of autophagic-lysosomal pathway dysfunctions’ role in the pathogenesis and progression of synucleinopathies opened new perspectives for novel possible therapeutic strategies. In this article, the evidences and mechanisms of the reciprocal relation between autophagic-lysosomal pathway impairment and misfolded α-syn aggregation and propagation are reviewed, together with the most promising compounds targeting autophagic-lysosomal pathway restoration as a disease-modifying strategy for PD treatment. © 2019 International Parkinson and Movement Disorder Society     

小鼠胸腺巨噬细胞吞噬周期的超微结构及细胞化学的观察

本实验对正常小鼠胸腺巨噬细胞内外源性物质消化(异噬)和内源性物质消化(自噬)过程中的形态学改变和酸性磷酸酶(AcPase)活性进行了观察。发现在巨噬细胞吞噬过程中,其溶酶体系有周期性改变。根据这一周期性改变本文提出了吞噬周期的概念。此周期可分为异噬阶段和自噬阶段。异噬阶段主要表现为吞噬机能增强和形成大量不规则(变形)的异噬溶酶体(HPL)。然后。通过变形HPL的发芽和缢缩形成许多小溶酶体.在自噬阶段,许多小溶酶体被变形HPL包裹。应该指出,自噬阶段巨噬细胞的自噬是HPL的自身吞噬现象。     

炔诺酮肟对家兔卵巢作用的形态学研究

家兔从妊娠第1天始,每天经口给予炔诺酮肟4mg/kg,连续3天,第9天处死。取卵巢作HE、ACP、ALP、SDH及3β-HSD染色,部分卵巢作超微结构观察。结果表明:炔诺酮肟呈明显的抗着床作用,卵巢黄体平坦,缩小。光镜观察,黄体细胞呈较明显的颗粒变性及空泡变性。组化染色,ACP活性增强(P<0.01)。3β-HSD活性减弱(P<0.01),ALP及SDH活性无明变化(P>0.05)。超微结构可见,黄体细胞胞质中滑面内质网明显减少,脂滴聚集,溶酶体数量增多,形状多样,脂质空泡化及类似髓鞘样结构等。提示由于药物抑制了卵巢3β-HSD活性,使卵巢激素生物合成受阻;此外,ACP活性增加,提示溶酶体通透性增加。     

大鼠第2段近端肾小管溶酶体电镜观察及其标志酶的测定

应用电子显微镜观察了大鼠第２段近端肾小管溶酶体系统超微结构。用显微分光光度计对溶酶体标志酶酸性磷酸酶和芳香硫酸酯酶作了测定。结果显示：溶酶体系统由有衣小泡、致密体、多泡体、消化泡、自噬体和残体组成；定量测定表明：酸性磷酸酶高于芳香硫酸酯酶（Ｐ＜０．０５），并讨论了肾小管内溶酶体结构功能与临床的关系。