Telomeres and pericentromeres are regions of heterochromatin that are difficult to replicate. Telomeric binding factor 2 (TRF2) is a key telomere protective protein that acts against DNA damage at telomeres and allows the progression of replication forks through telomere chromatin, a region with heterochromatin features that is difficult to replicate. TRF2 is also required at pericentromeres for proper replication elongation. Here, we show that TRF2 positively regulates the activity of protein phosphatase 2A (PP2A) by activating the expression of PPP2R2C, a gene encoding an isoform of the regulatory subunit of PP2A with particularly elevated expression in neuronal tissues. Mechanistically, we provide evidence that TRF2 binds to an intronic interstitial telomeric sequence (ITS) of PPP2R2C with transactivation activity. Moreover, PPP2R2C is recruited to telomeres and pericentromeres during S phase and during replicative stress where it attenuates the DNA damage response. Finally, we show that the TRF2-dependent regulation of PPP2R2C expression plays an important role in maintaining neurodevelopment in zebrafish. These results reveal a mechanism required for normal neurodevelopment by which TRF2 attenuates DNA damage by upregulating PPP2R2C, thereby stimulating PP2A activity at two regions difficult to replicate: telomeres and pericentromeres.

The contribution of cellular senescence to the behavioral changes observed in the elderly remains elusive. Here, we observed that aging is associated with a decline in protein phosphatase 2A (PP2A) activity in the brains of zebrafish and mice. Moreover, drugs activating PP2A reversed age-related behavioral changes. We developed a transgenic zebrafish model to decrease PP2A activity in the brain through knockout of the ppp2r2c gene encoding a regulatory subunit of PP2A. Mutant fish exhibited the behavioral phenotype observed in old animals and premature accumulation of neural cells positive for markers of cellular senescence, including senescence-associated β-galactosidase, elevated levels cdkn2a/b, cdkn1a, senescence-associated secretory phenotype gene expression, and an increased level of DNA damage signaling. The behavioral and cell senescence phenotypes were reversed in mutant fish through treatment with the senolytic ABT263 or diverse PP2A activators as well as through cdkn1a or tp53 gene ablation. Senomorphic function of PP2A activators was demonstrated in mouse primary neural cells with downregulated Ppp2r2c. We conclude that PP2A reduction leads to neural cell senescence thereby contributing to age-related behavioral changes and that PP2A activators have senotherapeutic properties against deleterious behavioral effects of brain aging.

Targeting of PP2A suggests a close link to tau-related cognitive and functional declines. However, little is known about how the expression of PP2A subunits and PP2A activity are dysregulated in the course of AD, precluding any specific targeting strategy for restoring PP2A in AD patients. Although the PP2A heterotrimer containing the regulatory subunit PR55/Bα (encoded by the PPP2R2A gene) is the major tau phosphatase, the involvement of other brain-specific PP2A regulatory subunits in tau dephosphorylation remains unknown. PR55/Bγ (encoded by the PPP2R2C gene) is a pivotal phosphatase in the brain, and single-nucleotide polymorphisms (SNPs) of PPP2R2C are involved in several mental disorders. By measuring the differential spatiotemporal expression patterns of PPP2R2C in Wt and transgenic AD mice, we revealed that PPP2R2C expression is downregulated in the aged AD mouse brain as compared to the Wt mouse brain. In cultured cells, PPP2R2C expression regulates PP2A activity and tau dephosphorylation. These results suggest that dysregulation of PPP2R2C expression may be involved in the onset of AD and that specifically targeting PPP2R2C expression or activity is a promising strategy against brain dementia disorders, including AD and other tauopathies.

目的 分析抗中性粒细胞胞浆抗体(antineutrophil cytoplasmic antibody,ANCA)相关性血管炎的临床特点和误诊原因.方法 对上海交通大学医学院附属新华医院近2年新确诊且收治入院的16例ANCA相关性血管炎误诊资料进行回顾性分析.结果 本组出现咳嗽、咳痰10例,下肢水肿9例,呕吐、腹泻等消化道症状8例,发热6例,咯血、呼吸困难3例,腰痛及关节、肌肉疼痛各2例,眼部炎症1例;其中9例表现为多系统症状体征.病初误诊为肺部感染、肾功能不全6例,肺部感染、肾功能不全、结肠溃疡性疾病2例,肺部感染、肾功能不全、消化道出血各2例,风湿性多肌痛1例,肺部感染、肾功能不全、消化道出血、眼部感染1例.误诊时间最短10 d,最长3年余.根据临床症状和自身免疫抗体及病理检查结果,明确ANCA相关性血管炎诊断,确诊后予糖皮质激素、环磷酰胺、血浆置换等治疗,随访至今1例需永久血液透析治疗,4例死亡.结论 ANCA相关性血管炎初期临床表现多样,容易误漏诊;对于出现多器官受累且病情迁延不愈者需考虑本症,常规筛查自身免疫抗体有助于本病诊断,必要时可行活检明确诊断.

Objective To identify prognostic factors for mortality in patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT).Methods A retrospective study was conducted in 138 patients with initiated CRRT due to AKI who were admitted to the Emergency Intensive Care Unit of Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine from May 2012 to December 2016. According to whether these patients survived after 28 days, they were divided into the death group (58 cases) and survived group (80 cases). Demographic and clinical parameters were retrieved and compared between the two groups. Logistic multivariate regression analysis was performed to determine the risk factors related to mortality.Results Of the 138 patients included, 58 patients (42.0％) died after 28 days. Patients in the death group were older, more likely to be male, had a higher score on the acute physiology and chronic health evaluationⅡ (APACHEⅡ), higher serum lactate level and lower serum creatinine level on admission, higher prevalence of coronary artery disease, and were more likely to be mechanically ventilated or treated with vasopressors. Multivariate logistic regression analysis revealed that age (OR=1.064, 95％CI: 1.022-1.108,P=0.002), APACHEⅡ score (OR=1.127, 95％CI: 1.003-1.265,P=0.044), mechanical ventilation (OR=7.432, 95％CI: 2.183-25.308, P=0.001) and use of vasopressors (OR=24.558, 95％CI: 7.651-78.825,P<0.01) were independent risk factors for mortality.Conclusions Older age, higher APACHEⅡ score, mechanical ventilation and use of vasopressors are risk factors for mortality in EICU patients with acute kidney injury requiring CRRT.

目的:探讨抗肿瘤药物RHPS4影响端粒重复序列结合因子2(TRF2)对端粒保护作用的机制.方法:在过表达TRF2的A375细胞体系中加入RHPS4,通过蛋白质印迹及免疫荧光结合共聚焦显微镜成像技术检测细胞DNA损伤情况,通过流式细胞技术及细胞增殖实验检测药物对细胞增殖的影响.结果:在A375细胞中过表达外源性TRF2能抑制DNA损伤的修复,但过表达TRF2不能抑制RHPS4诱导端粒损伤,RHPS4诱导的细胞周期停滞和细胞衰老过表达不依赖于TRF2的表达量.结论:TRF2高水平表达不能拮抗RHPS4的致端粒损伤和细胞周期抑制的作 用,肿瘤细胞中高表达TRF2不是应用RHPS4药物的反指征.

Objective To construct plasmids containing protein phosphatase 2A(PP2A) regulatory subunit PR55-γ(PPP2R2C) gene and transduct it into U87 cells for over-expressing PPP2R2 C, and to explore the effect of PPP2R2 C on PP2 A activity. Methods PPP2R2 C cDNA sequence was obtained by RT-PCR amplification and cloned into slow virus vector PWPIR-enhanced green fluorescent protein(EGFP); the construction of PWPIR-EGFP-PPP2R2 C vector was confirmed by restrictive enzyme digestion and DNA sequencing. The plasmid PWPIR-EGFP-PPP2R2 C was transducted into U87 cells by calcium phosphate precipitation method. The PPP2R2 C expression was detected by Western blotting. Fluorescence activated cell sorting was used to detect the transduction efficiency. PP2 A activity was detected by PP2 A protein co-immunoprecipitation(COIP). Results PWPIR-EGFP-PPP2R2 C plasmid was constructed successfully and expressed in U87 cells, and the transduction efficiency was 90%. The expression of exogenous PPP2R2 C was elevated to about 23 times the endogenous one. Over-expressing PPP2R2 C could enhance PP2 A activity. Conclusions PPP2R2 C was successfully constructed and expressed in U87 cells, and PP2 A activity was enhanced with the over-expressing of PPP2R2 C,which would provide the foundation for further studies on biological function of PPP2R2 C.

ObjectiveChina launched a health care reform policy due to the aging population and rapid urbanization. However, emergency overcrowding is not improved. We assessed the laboratory efficiency of emergency department (ED) in Shanghai hospitals.MethodsWe recorded the turn around times for processing laboratory biomarkers to assess laboratory efficiency at 17 EDs in national/regional hospitals. We compared TAT between national and regional hospitals and between central and ED laboratories to analyze the relationship between the laboratory efficiency and the ED overcrowding.ResultsAll the participating hospitals have an emergency laboratory. The median TAT for c-TNT was 61 min (46-76 min) at regional EDs compared with 64 min (46-87 min) at national EDs; therefore, the TAT at regional EDs were more efficient (P < 0.05). The TAT were longer (65 min (53-85 min)) at ED labs than (60 min (42-83 min)) at central labs (P < 0.05), independent of the hospital tier and working period. We discovered that only 9% of investigated samples at Tier II EDs and 5% at Tier III EDs were assayed by point-of-care (POC) instruments.ConclusionOur TAT level is approaching the recommended international standard. However, the TAT evaluation from ED laboratories demonstrates that their existence does not decrease the waiting time for laboratory reports compared to central laboratory. Thus, they have not yet approached a level to share the burden of the ED overcrowding. Further arrangement should be assigned to separate the function of emergency laboratory and central laboratory. It is worth deploying the POC assay in the ED, which will save twice the TAT level. The idea of evaluating routine laboratory efficiency by TAT at ED is fast, convenient, although it does not represent the general level of laboratory efficiency.

We assessed the efficiency of point-of-care (POC) tests in the emergency department (ED) by comparing them with the international standard. We recorded the turnaround times (TATs) for processing laboratory biomarkers to assess laboratory efficiency from 17 EDs in national/regional hospitals. We also compared patient components between national and regional hospitals. Although the 17 enrolled hospitals expanded their EDs, they contained only five POC machines among them. The P-50 (P-25, P-75) of the TATs for POC tests was 47 min (39, 55.5 min) for cardiac troponin T, which was much longer than the international standard (30 min). The TATs of other cardiac biomarkers were also longer than 30 min. The low efficiency of TATs for POC tests was a common feature in both regional and national hospitals (p > 0.05). Myocardial infarction was diagnosed in 61% of investigated ED patients who visited national hospitals, which is more frequently than those diagnosed at regional hospitals (46%, p < 0.05). Chronic heart failure was less frequent at national hospitals (28%) than at regional hospitals (41%, p < 0.05). The patient distribution in this study indicates that patients have the tendency to choose hospitals when they are affected with chest pain. However, the POC panel is rarely used in the ED, which delayed the TAT level and affected laboratory efficiency. This finding indicates a severe problem in the administrative management of EDs. This issue should be addressed in the next version of the medical reform policy.

目的探讨胶体金法检测肌钙蛋白I(cTnI)对急性心肌梗死(AMI)诊断的意义.方法对130例怀疑AMI患者分别采用胶体金法及免疫发光法检测血清cTnI水平,其结果分别进行相互间及与临床诊断比较,分析二者测定cTnI的灵敏度、特异度、符合率及一致性.结果胶体金法与免疫发光法检测血清cTnI水平,结果比较差异无统计学意义,具有极好的一致性,其灵敏度、特异度、符合率分别为93.5%、100%、95%.结论胶体金法对cTnI进行定性检测,操作简便、快速,特异度和灵敏度高,用血量少,可作为院前急救重要的检验方法,有助于早期诊断,及时指导治疗,减少AMI的病死率.