Necroptotic TNFα-Syndecan 4-TNFα Vicious Cycle as a Therapeutic Target for Preventing Temporomandibular Joint Osteoarthritis

Temporomandibular joint osteoarthritis (TMJOA) is a chronic degenerative disease for which the underlying mechanism still remains unclear. Compared with apoptosis and autophagy, necroptosis causes greater harm to tissue homeostasis by releasing damage-associated molecular patterns (DAMPs). However, the role of necroptosis and downstream key DAMPs in TMJOA is unknown. Here, rodent models of TMJOA were established by the unilateral anterior crossbite (UAC). Transmission electron microscopy (TEM) and immunohistochemistry of receptor interacting protein kinase 3 (RIPK3)/phosphorylation of mixed lineage kinase domain-like protein (pMLKL) were conducted to evaluate the occurrence of necroptosis in vivo. The therapeutic effects of blocking necroptosis were achieved by intra-articularly injecting RIPK3 or MLKL inhibitors and using RIPK3 or MLKL knockout mice. In vitro necroptosis of condylar chondrocyte was induced by combination of tumor necrosis factor alpha (TNFα), second mitochondria-derived activator of caspases (SMAC) mimetics and carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone (z-VAD-fmk). The possible DAMPs released by necroptotic chondrocytes were screened by quantitative proteomics and blocked by specific antibody. Translucent cytosol, swollen organelles, and ruptured cell membranes, features of necroptosis, were frequently manifested in chondrocytes at the early stage of condylar cartilage degeneration in TMJOA, which was accompanied by upregulation of RIPK3/pMLKL. Inhibiting or knocking out RIPK3/MLKL significantly prevented cartilage degeneration. DAMPs released by necroptotic condylar chondrocytes, such as syndecan 4 (SDC4) and heat shock protein 90 (HSP90), were verified. Furthermore, blocking the function of SDC4 significantly attenuated the expression of TNFα in cartilage and synovium, and accordingly increased cartilage thickness and reduced synovial inflammation. Thus, the necroptotic vicious cycle of TNFα-SDC4-TNFα contributes to cartilage degeneration and synovitis, and can serve as a potential therapeutic target for treating TMJOA. © 2022 American Society for Bone and Mineral Research (ASBMR).     

大骨节病患者踝关节软骨IGF-1、IGFBP2基因表达的特征及意义

目的探讨大骨节病(KBD)患者踝关节软骨胰岛素样生长因子1(IGF-1)、胰岛素样生长因子结合蛋白2(IGFBP2)基因表达的特征及意义。方法采用病例-对照研究方法,选择2010年1月至2016年12月在陕西省人民医院骨科住院的KBD患者10例为KBD组,并以同期因外伤致踝关节骨折但无距骨损伤的患者10例为对照组,收集两组患者软骨组织。分别采用免疫组织化学、实时荧光定量PCR及蛋白免疫印迹法检测患者软骨组织中IGF-1、IGFBP2阳性细胞、mRNA和蛋白表达情况。根据KBD患者踝关节软骨IGF-1、IGFBP2基因表达情况,在陕西省人民医院选择1例创伤致截肢患者,取踝关节软骨制备软骨细胞进行体外细胞验证实验;将软骨细胞分为对照组(0 ng/ml T-2毒素)、T-2处理组(20 ng/ml T-2毒素)、T-2+IGFBP2沉默组(20 ng/ml T-2毒素+50 nmol/L IGFBP2 siRNA),采用MTT法和二甲基亚甲基蓝染色法检测3组软骨细胞活性及硫酸糖胺多糖(sGAG)分泌情况。结果对照组与KBD组患者软骨组织IGF-1[(47.26±8.97)、(68.15±7.42)个]、IGFBP2阳性细胞数[(27.56±5.40)、(71.85±7.62)个]比较,差异均有统计学意义(t=4.487、9.402,P均<0.01);与对照组比较,KBD组患者软骨组织IGF-1、IGFBP2 mRNA和蛋白表达水平均较高,差异均有统计学意义(t=3.340、20.700,4.684、8.699,P<0.05或<0.01)。细胞实验中,对照组、T-2处理组、T-2+IGFBP2沉默组软骨细胞活性和sGAG含量比较,差异均有统计学意义(F=226.70、80.66,P均<0.01);其中,T-2处理组、T-2+IGFBP2沉默组细胞活性、sGAG含量均低于对照组(P均<0.05),且T-2+IGFBP2沉默组均高于T-2处理组(P均<0.05)。结论KBD患者踝关节软骨中IGF-1、IGFBP2基因表达明显较高。沉默IGFBP2基因能够降低T-2毒素对软骨细胞活性及sGAG分泌的抑制作用。     

Spike protein mediated membrane fusion during SARS-CoV-2 infection

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed a serious threat to public health and has quickly become a global concern. The infection of SARS-CoV-2 begins with the binding of its spike protein to the receptor-angiotensin-converting enzyme 2 (ACE2), which, after a series of conformation changes, results in the fusion of viral-cell membranes and the release of the viral RNA genome into the cytoplasm. In addition, infected host cells can express spike protein on their cell surface, which will interact with ACE2 on neighboring cells, leading to cell membrane fusion and the formation of multinucleated cells or syncytia. Both viral entry and syncytia formation are mediated by spike-ACE2 interaction and share some common mechanisms of membrane fusion. Here in this review, we will summarize our current understanding of spike-mediated membrane fusion, which may shed light on future broad-spectrum antiviral development.     

New strategies in achieving antiangiogenic effect: Multiplex inhibitors suppressing compensatory activations of RTKs

Pathological angiogenesis plays a crucial role in malignant neoplasia. Vascular normalization has been confirmed as a promising strategy to promote chemotherapy efficacy. However, compensatory activation of alternative angiogenic receptor tyrosine kinases (RTKs) reduces vascular normalization and induces resistance. Moreover, complexity and heterogeneity of angiogenesis make it difficult to treat with single‐target agents. Accordingly, it has been proposed that multiplex inhibition of RTKs could enhance treatment efficacy and overcome resistance on the basis of the vascular normalization concept. Meanwhile, it is feasible to develop multiplex inhibitors against VEGFR‐2/Tie‐2/EphB4 because of their highly conserved ATP‐binding pockets. These inhibitors possess the properties of not only stabilizing the vascular normalization “time window” but also preventing the occurrence of resistance. This novel strategy has yielded promising results in the discovery of antiangiogenic agents. This review highlights the recent progress on the development of such angiogenesis inhibitors.     

The potential health challenges of TiO2 nanomaterials

Titanium dioxide (TiO₂) nanomaterials (NMs) have found widespread applications owing to their attractive physical and chemical properties. As a result, the potential adverse impacts of nano‐TiO₂ exposure on humans have become a matter of concern. This review presents the state‐of‐the‐art advances on the investigations of the adverse effects of NMs, including the potential exposure routes of nano‐TiO₂ (e.g. respiratory system, skin absorption and digestive system), the physico‐chemical characterizations of nano‐TiO₂ (e.g. crystal structure, shape,size, zeta potential, treatment media, aggregation and agglomeration tendency, surface characteristics and coatings), risk evaluation of nanotoxicity (e.g. cytotoxicity, ecotoxicity, phototoxicity, and phytotoxicity) and potential mechanisms of adverse effects (e.g. generation of reactive oxygen species, oxidative stress and organelle dysfunction). The review aims to facilitate scientific assessments of health risks to nano‐TiO₂, which would guide the safe applications of NMs in our daily life. Copyright © 2015 John Wiley & Sons, Ltd.     

基于表面肌电图的人体运动意图识别研究进展

分析基于表面肌电图人体运动意图识别的研究方法和识别效果。     

Polymorphisms of ST2‐IL18R1‐IL18RAP gene cluster: a new risk for autoimmune thyroid diseases

Interleukin 33 (IL33) / ST2 pathway and ST2‐interlukin18 receptor1‐interlukin18 receptor accessory protein (ST2‐IL18R1‐IL18RAP) gene cluster have been involved in many autoimmune diseases but few report in autoimmune thyroid diseases (AITD). In this study, we investigated whether polymorphisms of IL33, ST2, IL18R1, and IL18RAP are associated with Graves' disease (GD) and Hashimoto's thyroiditis (HT), two major forms of AITD, among a Chinese population. A total of 11 SNPs were explored in a case–control study including 417 patients with GD, 250 HT patients and 301 controls, including rs1929992, rs10975519, rs10208293, rs6543116, rs1041973, rs3732127, rs11465597, rs1035130, rs2293225, rs1035127, rs917997 of IL 33, ST2‐IL18R1‐IL18RAP gene cluster. Genotyping of these SNPs was performed using matrix‐assisted laser desorption / ionization–time‐of‐flight mass spectrometer (MALDI‐TOF‐MS) platform from Sequenom. The frequencies of allele A and AA+AG genotype of rs6543116 (ST2) in HT patients were significantly increased compared with those of the controls (P = 0.029/0.021, OR = 1.31/1.62). And in another SNP rs917997, AA+AG genotype presented an increased frequency in HT subjects compared with controls (P = 0.046, OR = 1.53). Furthermore, the haplotype GAGCCCG from ST2‐IL18R1‐IL18RAP gene cluster (rs6543116, rs1041973, rs1035130, rs3732127, rs1035127, rs2293225, rs917997) was associated with increased susceptibility to GD with an OR of 2.03 (P = 0.022, 95% CI = 1.07–3.86). Some SNPs of ST2‐IL18R1‐IL18RAP gene cluster might increase the risk of susceptibility of HT and GD in Chinese Han population.     

视网膜色素上皮氧化损伤SIRT1表达改变

目的明确氧化应激对视网膜色素上皮细胞(RPE)中去乙酰化酶1(SIRT1)表达的影响。方法以人RPE细胞为实验对象,不同浓度H_2O_2(0、200、300μmol/L)处理RPE细胞,观察处理后24 h细胞形态的改变情况,检测处理后24 h与72 h细胞中SIRT1的mRNA与蛋白表达情况。结果 H_2O_2作用后,随H_2O_2浓度的增加,RPE细胞的形态受损,有凋亡小体的出现;在氧化应激24 h后细胞内SIRT1的转录水平增加,而在氧化应激72 h后SIRT1的蛋白表达显著下降。结论氧化应激可导致RPE细胞形态改变,SIRT1在RPE细胞内维持着氧化与抗氧化应激系统平衡,因此将SIRT1可作为临床上年龄相关性黄斑变性病(AMD)治疗的靶点。     

邻苯二甲酸二乙基己酯可能通过损伤血脑屏障诱导小鼠焦虑样行为和学习记忆障碍

目的 探讨邻苯二甲酸二乙基己酯（DEHP）对小鼠焦虑样行为和学习记忆能力的影响及机制。方法 将40只雄性ICR小鼠随机分为对照组（0 mg/kg）和DEHP暴露组（10、50、100 mg/kg）。通过灌胃暴露DEHP 4周,再进行开场实验、高架十字迷宫实验和Morris水迷宫实验。取小鼠海马组织检测丙二醛（MDA）含量,取大脑进行HE切片观察海马组织形态学变化,检测海马组织紧密连接蛋白ZO-1、Occludin的分子表达。结果 与对照组相比,4周DEHP暴露对各组小鼠体质量未造成明显的影响（P>0.05）。行为学实验表明,DEHP暴露组小鼠在开场中心区域的运动距离（P<0.05）和停留时间（P<0.05）少于对照组;在高架十字迷宫开臂区的运动距离和停留时间少于对照组（P<0.05）。在Morris水迷宫实验中,和对照组小鼠相比,DEHP暴露组小鼠找到平台的潜伏期明显延长（P<0.05）,且穿越平台位置的次数减少（P<0.05）。HE染色可以观察到海马CA1至CA3区出现明显的椎体细胞坏死,海马组织中MDA含量增加（P<0.05）,且与血脑屏障完整性相关的ZO-1和Occludin在基因（P<0.01）、蛋白（P<0.05）水平的表达也显著降低。此外,多元线性回归分析显示,DEHP诱导的小鼠焦虑样行为与学习记忆能力之间有密切的关联性。结论 DEHP暴露可能通过破坏血脑屏障,损伤海马椎体神经细胞,进而诱导小鼠焦虑样行为和学习记忆能力下降。     

利用1H-NMR技术研究大黄素染毒后大鼠内源性代谢物的改变

目的 采用¹H NMR的代谢组学技术揭示大黄素的肾毒性机制,寻找肾脏损害的早期生物标志物.方法 雄性SD大鼠20只,随机分为溶剂对照,大黄素170、500、1 500 mg/(kg·d)3个剂量组,连续给药16 d,给药结束后收集24 h尿液,血浆及肾组织,测定¹H NMR谱,并进行血浆生化指标测定和肝脏组织病理学检查.结果 1 500 mg/(kg·d)大黄素服用16 d可引起大鼠血肌酐下降,大黄素可导致肾细胞胞浆中出现明显的空泡化改变.代谢成分的改变主要表现为血液中乳酸、糖、氨基酸和脂肪酸成分下降;尿液中乳酸、糖和氨基酸成分增加;肾脏组织中醋酸盐和肌酐/肌酸明显升高,乳酸和胆碱/磷酸卵磷脂水平下降,饱和与不饱和脂肪酸及磷脂的成分比例明显改变.结论 代谢组学分析在识别药物诱导代谢成分改变方面较传统技术更灵敏;脂肪和能量代谢紊乱参与了大黄素的肾毒性,尿液中氨基酸、葡萄糖氧化三甲胺(TMAO)及肌酐可作为大黄素诱导肾组织损害的潜在生物标志物.