Identification of a chemotactic,MCP-1-like protein from Mycobacterium avium

In the immunocompetent host, Mycobacterium avium is responsible for chronic localized pulmonary disease, which is characterized by the presence of increased numbers of activated T cells and macrophages in the lungs. M. avium organisms as well as sonic extracts of M. avium were found to act as chemoattractants for THP-1 cells as well as monocytes, monocyte-derived macrophages and alveolar macrophages obtained from normal human donors in an in vitro chemotaxis assay, where a significantly higher number of cells were found in wells containing M. avium compared to control wells. Proteolytic treatment of M. avium sonicate resulted in significant loss (50%) of chemotactic activity. Monoclonal antibodies against recombinant human monocyte chemoattractant protein-1 (MCP-1) were found to cross-react with a 34-kDa protein of M. avium sonicate on Western blot and inhibit M. avium sonicate-mediated chemotaxis of THP-1 cells (47%). These data suggest the presence of an 'MCP-1 like' molecule on M. avium. Recruitment of host immune regulatory cells to the site of infection by pathogens may be involved in generating a local immune response or may be a bacterial strategy for survival within the host by recruiting the cells that they infect, i.e. macrophages.     

Exendin-4, a glucagon-like peptide-1 receptor agonist, reduces intimal thickening after vascular injury

Glucagon-like peptide-1 is a hormone secreted by L cells of the small intestine and stimulates glucose-dependent insulin response. Glucagon-like peptide-1 receptor agonists such as exendin-4 are currently used in type 2 diabetes, and considered to have beneficial effects on the cardiovascular system. To further elucidate the effect of glucagon-like peptide-1 receptor agonists on cardiovascular diseases, we investigated the effects of exendin-4 on intimal thickening after endothelial injury. Under continuous infusion of exendin-4 at 24 nmol/kg/day, C57BL/6 mice were subjected to endothelial denudation injury of the femoral artery. Treatment of mice with exendin-4 reduced neointimal formation at 4 weeks after arterial injury without altering body weight or various metabolic parameters. In addition, in vitro studies of isolated murine, rat and human aortic vascular smooth muscle cells showed the expression of GLP-1 receptor. The addition of 10 nM exendin-4 to cultured smooth muscle cells significantly reduced their proliferation induced by platelet-derived growth factor. Our results suggested that exendin-4 reduced intimal thickening after vascular injury at least in part by the suppression of platelet-derived growth factor-induced smooth muscle cells proliferation.     

Regenerating endothelial cells express insulin-like growth factor-I immunoreactivity after arterial injury

Summary In the present study the expression of insulin-like growth factor I (IGF-I; somatomedin C) immunoreactivity was examined in endothelial cells during repair after injury to the intima in the femoral artery of adult rats. Two types of injury were examined: (1) endothelial denudation induced by the use of a catheter, and (2) vessel compression by short-term ligation. In untreated rats, arterial endothelial cells showed no or, only infrequently, low IGF-I immunoreactivity in their cytoplasm. Endothelial cells at the border to the denuded area showed increased IGF-I immunoreactivity one day after injury to the intima of the femoral artery. Thrombocytes and fibrin deposits as well as vital endothelial cells, covered by clots, were immunonegative. The maximal intensity of IGF-I immunoreactivity was reached within 3 days after insult. The IGF-I immunoreactivity in the endothelial cells remained elevated for at least 4 weeks, compared to the controls. Intimai thickenings appeared within a week after injury and many cells in these thickenings showed intense IGF-I immunoreactivity as did the covering endothelial cells. Smooth muscle cells in the media were generally immunonegative during control conditions and after endothelial denudation. Spontaneously hypertensive rats (SHR) showed, similarly to their matched controls (WKY), approximately the same patterns of IGF-I immunoreactivity in their endothelial cells both under normal conditions and after injury. It is concluded that IGF-I is likely to be involved in the repair of the intima in injured arteries.     

High glucose accelerates MCP-1 production via p38 MAPK in vascular endothelial cells

In diabetes mellitus (DM), hyperglycemia causes cardiovascular lesions through endothelial dysfunction. Monocyte chemoattractant protein-1 (MCP-1) is implicated in the pathogenesis of cardiovascular lesions. By using human umbilical vein endothelial cells, we investigated the effect of hyperglycemia on MCP-1 production and its signaling pathways. Chronic incubation with high glucose increased mRNA expression and production rate of MCP-1 in a time (1-7 days)- and concentration (10-35 mM)-dependent manner. Chronic exposure to high glucose resulted in enhancement of generation of reactive oxygen species (ROS), as determined by increasing level of 2,7-dichlorofluorescein (DCF), and subsequent activation of p38 mitogen-activated protein kinase (MAPK). Neither c-Jun NH(2)-terminal kinase nor extracellular signal-regulated kinase1/2 was affected. SB203580 or FR167653, p38 MAPK specific inhibitors, completely suppressed MCP-1 expression. Catalase suppressed p38 MAPK phosphorylation and MCP-1 expression. These results indicate that hyperglycemia can accelerate MCP-1 production through the mechanism involving p38 MAPK, ROS-sensitive signaling pathway, in vascular endothelial cells.     

Angiotensin II type 1 receptor-associated protein regulates carotid intimal hyperplasia through controlling apoptosis of vascular smooth muscle cells

Intimal hyperplasia is the main cause of restenosis after carotid artery injury, and the underlying mechanism involves the proliferation and migration of vascular smooth muscle cells (VSMCs). Angiotensin II Type 1 Receptor-Associated Protein (ATRAP) has been reported to withstand intimal hyperplasia by inhibiting VSMCs proliferation and migration; however, whether the beneficial effect of ATRAP associates with VSMCs apoptosis remains unclarified. We demonstrated that the adenoviral-mediated overexpression of ATRAP induced VSMC apoptosis, alleviating the balloon injury-induced neointima formation in rats. Under the condition of Angiotensin-II stimulation, ATRAP overexpression induced the apoptosis of rat VSMCs by depressing the PI3K-Akt signaling; whereas up-regulation of Akt by PTEN inhibitor abolished the apoptotic death. Thus, ATRAP regulates carotid intimal hyperplasia through controlling the PI3K-Akt signal-mediated VSMCs apoptosis.     

Bone marrow-derived mesenchymal stem cells inhibit vascular smooth muscle cell proliferation and neointimal hyperplasia after arterial injury in rats

We investigated whether mesenchymal stem cell (MSC)-based treatment could inhibit neointimal hyperplasia in a rat model of carotid arterial injury and explored potential mechanisms underlying the positive effects of MSC therapy on vascular remodeling/repair. Sprague-Dawley rats underwent balloon injury to their right carotid arteries. After 2 days, we administered cultured MSCs from bone marrow of GFP-transgenic rats (0.8 × 10⁶ cells, n = 10) or vehicle (controls, n = 10) to adventitial sites of the injured arteries. As an additional control, some rats received a higher dose of MSCs by systemic infusion (3 × 10⁶ cells, tail vein; n = 4). Local vascular MSC administration significantly prevented neointimal hyperplasia (intima/media ratio) and reduced the percentage of Ki67 + proliferating cells in arterial walls by 14 days after treatment, despite little evidence of long-term MSC engraftment. Notably, systemic MSC infusion did not alter neointimal formation. By immunohistochemistry, compared with neointimal cells of controls, cells in MSC-treated arteries expressed reduced levels of embryonic myosin heavy chain and RM-4, an inflammatory cell marker. In the presence of platelet-derived growth factor (PDGF-BB), conditioned medium from MSCs increased p27 protein levels and significantly attenuated VSMC proliferation in culture. Furthermore, MSC-conditioned medium suppressed the expression of inflammatory cytokines and RM-4 in PDGF-BB-treated VSMCs. Thus, perivascular administration of MSCs may improve restenosis after vascular injury through paracrine effects that modulate VSMC inflammatory phenotype.     

托拉塞米联合川芎嗪注射液治疗慢性心力衰竭的疗效及对患者血清MCP-1、BNP、NGAL水平的影响

目的:探讨托拉塞米联合川芎嗪注射液治疗慢性心力衰竭的临床疗效及对患者血清单核细胞趋化蛋白因子-1(MCP-1)、脑钠肽(BNP)、中性粒细胞明胶酶相关脂质运载蛋白(NGAL)水平的影响。方法:选择2015年3月～2017年3月于我院住院的慢性心力衰竭患者100例,按随机数字表法将其分成治疗组(n=50)与对照组(n=50)。两组患者均给予相同的常规治疗,对照组在此基础上联合托拉塞米治疗,治疗组在对照组基础上加用川芎嗪注射液治疗。在完成2周治疗后,对两组进行疗效评价,比较两组治疗前后心功能、6 min步行距离(6MWT)及生活质量水平、血清MCP-1、BNP、NGAL水平的变化。结果:治疗组经2周治疗后总有效率为86.00%(43/50),与对照组[64.00%(32/50)]相比显著上升(P0.05)。治疗组治疗2周后左室射血分数(LVEF)值较治疗前显著升高(P0.05),而左室舒张/收缩末期容积(LVEDV/LVESV)均显著降低(P0.05);与治疗前对比,对照组治疗后LVEF值亦显著增加(P0.05),LVESV值显著下降(P0.05);且治疗组治疗后上述心功能指标改善效果均显著优于对照组同期(P0.05)。与治疗前相比,两组治疗2周后6MWT值均明显增加(P0.05),明尼苏达心力衰竭生活质量量表(LHFQ)评分及血清MCP-1、BNP、NGAL水平均明显降低(P0.05);且治疗组治疗后以上指标改善效果较对照组同期更显著(P0.05)。结论:托拉塞米联合川芎嗪注射液治疗慢性心力衰竭的临床疗效明显优于单用川芎嗪注射液治疗,其可有效改善患者心功能,提高生活质量,可能与其显著降低患者血清MCP-1、BNP、NGAL水平有关。     

辛伐他汀干预鼠颈动脉损伤MCP-1的表达

应用鼠颈动脉结扎模型,采用原位杂交、免疫组化技术观察血管单核细胞趋化蛋白-1(monocyte chemoattractant protein-1, MCP-1)的表达及内膜增生情况,探讨辛伐他汀抗内膜增生机制.结果发现损伤血管内膜增生明显,MCP-1的表达增加;辛伐他汀干预可明显抑制血管MCP-1的表达及新生内膜形成.提示血管内膜增生可能与MCP-1表达上调有关,辛伐他汀抑制内膜增生也许通过MCP-1介导.     

单核细胞趋化蛋白-1、高迁移率族蛋白B1与溃疡性结肠炎患者肠道菌群变化的相关性

目的 探讨单核细胞趋化蛋白-1（MCP-1）、高迁移率族蛋白B1（HMGB1）与溃疡性结肠炎（UC）患者肠道菌群变化的相关性。方法 选取2016年9月‒2018年1月遂宁市中心医院收治的98例UC患者资料,根据Mayo评分系统将UC患者分为活动期组（n=50）和缓解期组（n=48）。选取同期进行体检的健康人50例作为对照组。比较各组间肠道菌群,血清MCP-1、HMGB1水平,并进行Pearson相关分析。结果 活动期组患者肠道乳杆菌、双歧杆菌含量[（5.34±0.87）、（5.81±0.83）CFU/g]显著低于缓解期组和对照组[（8.07±0.86）、（8.35±0.88）CFU/g;（8.13±0.91）、（8.46±0.95）CFU/g]（F=12.035,P0.05）。活动期组和缓解期组患者血清MCP-1、HMGB1水平[（267.42±23.51）、（21.35±2.26）ng/mL;（188.15±20.73）、（6.28±1.38）ng/mL]显著高于对照组[（106.38±15.92）、（2.13±0.41）ng/mL]（F=84.163,P<0.001;F=25.386,P<0.001）;活动期组患者血清MCP-1、HMGB1水平[（267.42±23.51）、（21.35±2.26）ng/mL]显著高于缓解期组[（188.15±20.73）、（6.28±1.38）ng/mL]（t=17.676、39.641,均P<0.05）。经过Pearson相关性分析,MCP-1、HMGB1与UC患者乳杆菌、双歧杆菌含量呈负相关（r=‒0.715、‒0.659,r=‒0.703、‒0.614,均P<0.001）,与大肠埃希菌、肠球菌、拟杆菌含量呈正相关（r=0.783、0.702,r=0.762、0.735,r=0.653、0.612,均P<0.001）。结论 MCP-1、HMGB1作为促炎因子可介导肠黏膜炎性反应,引起UC患者肠道菌群的紊乱。     

Elevated serum levels of IL-1ra in children with Plasmodium falciparum malaria are associated with increased severity of disease

Animal models suggest that cytokines and chemokines play a role in cerebral malaria (CM) pathogenesis, but levels of a number of cytokines and chemokines thought to be important in the pathogenesis of other infectious diseases are not well characterized in children with CM. Serum levels of granulocyte-colony stimulating factor (G-CSF), interleukin-1 receptor antagonist (IL-1ra), interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) were measured in 77 children with CM, 70 children with uncomplicated malaria (UM) and 63 healthy community children (CC) in Uganda. Children with CM had elevated serum levels of IL-1ra and IL-8 as compared to children with UM (median levels in pg/ml, 11,891 vs. 6510, P = 0.05, and 63 vs. 41, P = 0.01, respectively). Children with CM who died (n = 4) had higher serum levels than survivors of IL-1ra (median levels in pg/ml, 65,757 vs. 10,355, P = 0.02), G-CSF (709 vs. 117, P = 0.02), and MCP-1 (1275 vs. 216, P = 0.03) but not IL-8 (76 vs. 62, P = NS). Elevated IL-1ra levels are associated with increased disease severity in children with malaria, and very elevated levels of IL-1ra, G-CSF and MCP-1 are seen in children who die of CM.     

RPLU术对重度肾积水的上尿路结石患者尿ET-1、AQP-1、MCP-1水平的影响

摘要 目的：探讨后腹腔镜下输尿管切开取石术（RPLU）对重度肾积水的上尿路结石患者尿内皮素-1（ET-1）、水通道蛋白-1（AQP-1）、单核细胞趋化蛋白-1（MCP-1）水平的影响。方法：收集2018年4月~2019年11月我院收治的106例重度肾积水的上尿路结石患者为研究对象,按照随机数字表法分为对照组和研究组,每组53例,对照组采用输尿管镜取石术治疗,研究组采用RPLU术治疗,对比两组手术情况,手术前后血红蛋白、肾功能、尿ET-1、AQP-1、MCP-1水平,手术并发症发生情况。结果：研究组手术时间及住院时间多于对照组,结石清除率高于对照组,比较差异有统计学意义（P<0.05）;两组术中出血量、术后排气时间比较差异无统计学意义（P>0.05）。术后,两组血红蛋白较术前无显著差异（P>0.05）。术后,两组血肌酐及血尿酸氮均下降,两组比较差异无统计学意义（P>0.05）。术后,两组尿ET-1、AQP-1、MCP-1水平均下降,两组比较无统计学意义（P>0.05）。两组并发症总发生率比较无统计学意义（P>0.05）。结论：RPLU术是治疗重度肾积水的上尿路结石清除率高,创伤小,可作为重度肾积水伴上尿路结石安全、有效的术式。     

Smooth muscle cell injury after cryopreservation of human thoracic aortas

The cryopreservation protocol we use for arterial reconstructive surgery has been studied to evaluate smooth muscle cell (SMC) structural integrity and viability before implantation. Samples of human thoracic aortas (HTA) were harvested from five multi-organ donors. Sampling included unfrozen and cryopreserved specimens. Cryopreservation was performed using RPMI with human albumin and 10% Me(2)SO in a controlled-rate freezing apparatus. Thawing was accomplished by submerging bags in a water bath (39 degrees C) followed by washings in cooled saline. In situ cell preservation as investigated by light and transmission electron microscopy showed that SMCs from cryopreserved HTA had nuclear and cytoplasmic changes. A TUNEL assay, performed to detect DNA fragmentation in situ, showed increased SMC nuclear positivity in cryopreserved HTA when compared to unfrozen samples. 7-AAD flow cytometry assay of cells derived from cryopreserved HTA showed that an average of 49+/-16% cells were unlabeled after cryopreservation. Organ cultures aimed to study cell ability to recover cryopreservation damage showed a decreasing number of SMCs from day 4 to day 15 in cryopreserved HTA. In conclusion, the cryopreservation protocol applied in this study induces irreversible damage of a significant fraction of arterial SMCs.     

Inhibition of VRK1 suppresses proliferation and migration of vascular smooth muscle cells and intima hyperplasia after injury via mTORC1/β-catenin axis

Characterized by abnormal proliferation and migration of vascular smooth muscle cells (VSMCs), neointima hyperplasia is a hallmark of vascular restenosis after percutaneous vascular interventions. Vaccinia-related kinase 1 (VRK1) is a stress adaption-associated ser/thr protein kinase that can induce the proliferation of various types of cells. However, the role of VRK1 in the proliferation and migration of VSMCs and neointima hyperplasia after vascular injury remains unknown. We observed increased expression of VRK1 in VSMCs subjected to platelet-derived growth factor (PDGF)-BB by western blotting. Silencing VRK1 by shVrk1 reduced the number of Ki-67-positive VSMCs and attenuated the migration of VSMCs. Mechanistically, we found that relative expression levels of β-catenin and effectors of mTOR complex 1 (mTORC1) such as phospho (p)-mammalian target of rapamycin (mTOR), p-S6, and p-4EBP1 were decreased after silencing VRK1. Restoration of β-catenin expression by SKL2001 and re-activation of mTORC1 by Tuberous sclerosis 1 siRNA (siTsc1) both abolished shVrk1-mediated inhibitory effect on VSMC proliferation and migration. siTsc1 also rescued the reduced expression of β-catenin caused by VRK1 inhibition. Furthermore, mTORC1 re-activation failed to recover the attenuated proliferation and migration of VSMC resulting from shVrk1 after silencing β-catenin. We also found that the vascular expression of VRK1 was increased after injury. VRK1 inactivation in vivo inhibited vascular injury-induced neointima hyperplasia in a β-catenindependent manner. These results demonstrate that inhibition of VRK1 can suppress the proliferation and migration of VSMC and neointima hyperplasia after vascular injury via mTORC1/β-catenin pathway.     

Increase of smooth muscle cell migration and of intimal hyperplasia in mice lacking the alpha/beta hydrolase domain containing 2 gene

Multiple steps, including the migration of vascular smooth muscle cells (SMCs), are involved in the pathogenesis of atherosclerosis. To discover genes which are involved in these steps, we screened mutant mouse lines established by the exchangeable gene trap method utilizing X-gal staining during their embryonic development. One of these lines showed strong reporter gene expression in the vitelline vessels of yolk sacs at embryonic day (E) 12.5. The trap vector was inserted into the fifth intron of alpha/beta hydrolase domain containing 2 (Abhd2) gene which was shown to be expressed in vascular and non-vascular SMCs of adult mice. Although homozygous mutant mice were apparently normal, enhanced SMC migration in the explants SMCs culture and marked intimal hyperplasia after cuff placement were observed in homozygous mice in comparison with wild-type mice. Our results show that Abhd2 is involved in SMC migration and neointimal thickening on vascular SMCs.     

Thrombin impairs the angiogenic activity of extravillous trophoblast cells via monocyte chemotactic protein-1 (MCP-1): A possible link with preeclampsia

Cytokines’ secretion from the decidua and trophoblast cells has been known to regulate trophoblast cell functions, such as Extravillous trophoblasts (EVTs) cell migration and invasion and remodeling of spiral arteries. Defective angiogenesis and spiral arteries transformation are mainly caused by proinflammatory cytokines and excessive thrombin generation during preeclampsia. Monocyte chemotactic protein-1 (MCP-1), a crucial cytokine, has a role in maintaining normal pregnancy. In this study, we explored whether thrombin regulates the secretion of MCP-1 in HTR-8/SVneo cells; if yes, what is its function? We used HTR-8/SVneo cells, developed from ?rst trimester villous explants of early pregnancy, as the model of EVTs. MCP-1 gene silencing was performed using gene-specific siRNA. qPCR and ELISA were performed to estimate the expression and secretion of MCP-1. Here, we found that thrombin enhanced the secretion of MCP-1 in HTR-8/SVneo cells. Proteinase-activated receptor-1 (PAR-1) was found as the primary receptor, regulating MCP-1 secretion in these cells. Furthermore, MCP-1 secretion is modulated via protein kinase C (PKC) α, β, and Rho/Rho-kinase-dependent pathways. Thrombin negatively regulates HTR-8/SVneo cells’ ability to mimic tube formation in an MCP-1 dependent manner. In conclusion, we propose that thrombin-controlled MCP-1 secretion may play an essential role in normal placental development and successful pregnancy maintenance. Improper thrombin production and MCP-1 secretion during pregnancy might cause inadequate vascular formation and transformation of spiral arteries, which may contribute to pregnancy disorders, such as preeclampsia.     

中枢神经系统感染患者脑脊液和血清中MMP-2、MMP-9、MCP-1表达的研究

目的探讨中枢神经系统感染患者脑脊液和血清中MMP-2(基质金属蛋白2)、MMP-9(基质金属蛋白9)、MCP-1(单核细胞趋化蛋白-1)表达的意义。方法选取2012年12月至2014年5月我院收治的中枢神经系统感染患者60例,其中结核性脑膜炎组(TBM组)、化脓性脑膜炎组(PM组)、真菌性脑膜炎组(CM组)和病毒性脑膜炎组(VM组)各15例;另外选取同期健康体检者15例作为对照组。治疗前、治疗后检测5组患者脑脊液常规及生化,采用ELISA法检测其脑脊液及血清中MMP-2、MMP-9、MCP-1的表达,并对患者进行格拉斯哥昏迷评分(GCS),分析其内在联系。结果治疗前、治疗后TBM组、PM组、CM组和VM组的脑脊液细胞数、蛋白水平均高于对照组,且TBM组、PM组的脑脊液细胞数、蛋白水平均高于CM组和VM组(P0.05);治疗前、治疗后TBM组、PM组、CM组和VM组的脑脊液糖水平、GCS评分低于对照组,治疗前TBM组、PM组、CM组、VM组的脑脊液氯化物水平低于对照组(P0.05);治疗后四组与对照组在脑脊液氯化物水平以及GCS评分等方面的差异无统计学意义(P0.05);治疗前、治疗后TBM组、PM组、CM组、VM组的脑脊液和血清中MMP-2、MMP-9、MCP-1水平均显著高于对照组,且治疗前TBM组、PM组的脑脊液和血清中MMP-2、MMP-9、MCP-1水平均显著高于CM组、VM组以及对照组(P0.05);治疗后PM组、CM组、VM组的脑脊液和血清中MMP-2、MMP-9、MCP-1水平的差异无统计学意义(P0.05);经Pearson进行相关性分析,BM组、PM组、CM组以及VM组的脑脊液和血清中MMP-2、MMP-9、MCP-1表达均与GCS评分负相关(相关系数r=-0.859~-0.574,P0.05)。结论中枢神经系统感染患者脑脊液和血清中MMP-2、MMP-9、MCP-1表达均与GCS评分相关,动态检测脑脊液和血清中MMP-2、MMP-9、MCP-1表达均对中枢神经系统感染的诊断和判断预后有积极意义。     

Impaired autophagy flux is associated with neuronal cell death after traumatic brain injury

Dysregulation of autophagy contributes to neuronal cell death in several neurodegenerative and lysosomal storage diseases. Markers of autophagy are also increased after traumatic brain injury (TBI), but its mechanisms and function are not known. Following controlled cortical impact (CCI) brain injury in GFP-Lc3 (green fluorescent protein-LC3) transgenic mice, we observed accumulation of autophagosomes in ipsilateral cortex and hippocampus between 1 and 7 d. This accumulation was not due to increased initiation of autophagy but rather to a decrease in clearance of autophagosomes, as reflected by accumulation of the autophagic substrate SQSTM1/p62 (sequestosome 1). This was confirmed by ex vivo studies, which demonstrated impaired autophagic flux in brain slices from injured as compared to control animals. Increased SQSTM1 peaked at d 1–3 but resolved by d 7, suggesting that the defect in autophagy flux is temporary. The early impairment of autophagy is at least in part caused by lysosomal dysfunction, as evidenced by lower protein levels and enzymatic activity of CTSD (cathepsin D). Furthermore, immediately after injury both autophagosomes and SQSTM1 accumulated predominantly in neurons. This was accompanied by appearance of SQSTM1 and ubiquitin-positive puncta in the affected cells, suggesting that, similar to the situation observed in neurodegenerative diseases, impaired autophagy may contribute to neuronal injury. Consistently, GFP-LC3 and SQSTM1 colocalized with markers of both caspase-dependent and caspase-independent cell death in neuronal cells proximal to the injury site. Taken together, our data indicated for the first time that autophagic clearance is impaired early after TBI due to lysosomal dysfunction, and correlates with neuronal cell death.     

Impaired autophagy flux is associated with neuronal cell death after traumatic brain injury

Dysregulation of autophagy contributes to neuronal cell death in several neurodegenerative and lysosomal storage diseases. Markers of autophagy are also increased after traumatic brain injury (TBI), but its mechanisms and function are not known. Following controlled cortical impact (CCI) brain injury in GFP-Lc3 (green fluorescent protein-LC3) transgenic mice, we observed accumulation of autophagosomes in ipsilateral cortex and hippocampus between 1 and 7 d. This accumulation was not due to increased initiation of autophagy but rather to a decrease in clearance of autophagosomes, as reflected by accumulation of the autophagic substrate SQSTM1/p62 (sequestosome 1). This was confirmed by ex vivo studies, which demonstrated impaired autophagic flux in brain slices from injured as compared to control animals. Increased SQSTM1 peaked at d 1–3 but resolved by d 7, suggesting that the defect in autophagy flux is temporary. The early impairment of autophagy is at least in part caused by lysosomal dysfunction, as evidenced by lower protein levels and enzymatic activity of CTSD (cathepsin D). Furthermore, immediately after injury both autophagosomes and SQSTM1 accumulated predominantly in neurons. This was accompanied by appearance of SQSTM1 and ubiquitin-positive puncta in the affected cells, suggesting that, similar to the situation observed in neurodegenerative diseases, impaired autophagy may contribute to neuronal injury. Consistently, GFP-LC3 and SQSTM1 colocalized with markers of both caspase-dependent and caspase-independent cell death in neuronal cells proximal to the injury site. Taken together, our data indicated for the first time that autophagic clearance is impaired early after TBI due to lysosomal dysfunction, and correlates with neuronal cell death.     

时钟基因BMAL1在运动性骨骼肌损伤恢复中的作用

目的:探讨时钟基因BMAL1在运动性骨骼肌损伤恢复中的作用。方法:208只8周龄SD大鼠随机分为对照组(C组,n=104)和运动组(E组,n=104)。E组于跑台进行90 min下坡跑,运动后于0 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, 48 h, 54 h, 60 h, 66 h, 72 h各取C组、E组8只大鼠腓肠肌,通过实时荧光定量PCR实验检测骨骼肌核心时钟基因BMAL1表达量,应用余弦分析软件circacompare (R package)获取拟合余弦曲线参数,分析其节律性振荡的变化趋势;透射电镜观察骨骼肌肌纤维超微结构变化;免疫印迹法(Western blot)检测骨骼肌BMAL1、DESMIN表达;免疫荧光观测BMAL1与DESMIN的定位及含量变化。结果:C组BMAL1 mRNA在72 h内呈现3个完整近日节律周期;E组BMAL1 mRNA在0 h～24 h近日节律消失。与C组比较,E组在运动后0 h、6 h、12 h、18 h, BMAL1 mRNA含量显著升高(P<0.05),在运动后0 h、12 hBMAL1蛋...