The global outbreak of SARS in 2002-2003 was caused by the infection of a new human coronavirus SARS-CoV. The infection of SARS-CoV is mediated mainly through the viral surface glycoproteins, which consist of S1 and S2 subunits and form trimer spikes on the envelope of the virions. Here we report the ectodomain structures of the SARS-CoV surface spike trimer in different conformational states determined by single-particle cryo-electron microscopy. The conformation 1 determined at 4.3 resolution is three-fold symmetric and has all the three receptor-binding C-terminal domain 1 (CTD1s) of the S1 subunits in "down" positions. The binding of the "down" CTD1s to the SARS-CoV receptor ACE2 is not possible due to steric clashes, suggesting that the conformation 1 represents a receptor-binding inactive state. Conformations 2-4 determined at 7.3, 5.7 and 6.8 resolutions are all asymmetric, in which one RBD rotates away from the "down" position by different angles to an "up" position. The "up" CTD1 exposes the receptor-binding site for ACE2 engagement, suggesting that the conformations 2-4 represent a receptor-binding active state. This conformational change is also required for the binding of SARS-CoV neutralizing antibodies targeting the CTD1. This phenomenon could be extended to other betacoronaviruses utilizing CTD1 of the S1 subunit for receptor binding, which provides new insights into the intermediate states of coronavirus pre-fusion spike trimer during infection.
Oxidative stress plays a central role in the pathogenesis of various neurodegenerative diseases. Increasing evidences have demonstrated that structural abnormalities in mitochondria are involved in oxidative stress related nerve cell damage. And Drp1 plays a critical role in mitochondrial dynamic imbalance insulted by oxidative stress-derived mitochondria. However, the status of mitochondrial fusion and fission pathway and its relationship with mitochondrial properties such as mitochondrial membrane permeability transition pore (mPTP) have not been fully elucidated. Here, we demonstrated for the first time the role of Cyclophilin D (CypD), a crucial component for mPTP formation, in the regulation of mitochondrial dynamics in oxidative stress treated nerve cell. We observed that CypDmediated phosphorylation of Drp1 and subsequently augmented Drp1 recruitment to mitochondria and shifts mitochondrial dynamics toward excessive fission, which contributes to the mitochondrial structural and functional dysfunctions in oxidative stress-treated nerve cells. CypD depletion or over expression accompanies mitochondrial dynamics/functions recovery or aggravation separately. We also demonstrated first time the link between the CypD to mitochondrial dynamics. Our data offer new insights into the mechanism of mitochondrial dynamics which contribute to the mitochondrial dysfunctions, specifically the role of CypD in Drp1-mediated mitochondrial fission. The protective effect of CsA, or other molecules affecting the function of CypD hold promise as a potential novel therapeutic strategy for governing oxidative stress pathology via mitochondrial pathways. (C) 2016 Elsevier Inc. All rights reserved.
We performed studies to determine the role of high-mobility group box 1 (HMGB1) in cigarette smoke (CS)-induced pulmonary inflammation. After mice were exposed to five cigarettes four times a day for 3 d, toll-like receptor 4 (TLR4) expression and TLR4-mediated signaling were significantly up-regulated, and HMGB1 had translocated from the nucleus to the cytoplasm in lung epithelial cells and then been released into the extracellular lung space. On CS exposure, inflammatory cell recruitment and proinflammatory cytokine production were significantly increased in lung tissue and bronchoalveolar lavage, and these effects depended on the TLR4 signaling pathway. HMGB1 inhibition decreased the CS-induced inflammatory response, whereas treatment with exogenous HMGB1 aggravated the damage and increased the phosphorylation of JNK, p38, and I kappa Ba in the lungs of wild-type mice but not in TLR4-knockout mice. Blockade of TLR4 action or TLR4 knockout significantly inhibited HMGB1-induced proinflammatory cytokine production in mouse tracheal epithelial (MTE) cells and lung tissues. In addition, a MyD88 deficiency inhibited JNK, p38, and I.Ba phosphorylation, and this effect was associated with the suppressed production of TNF-alpha and IL-1 beta in MTE cells and lung tissues in response to CS stimulation. Thus HMGB1 activates the NF-kappa B and JNK/p38 pathways through TLR4/MyD88-dependent signaling and induces an inflammatory response in lungs exposed to CS.
Objective: We describe the features of non-contiguous 2-level cervical degenerative disc disease (NCDDD), investigate the safety and feasibility of artificial cervical disc replacement (ACDR) for the treatment of NCDDD, and expect that our study will provide spine surgeons with an alternative procedure for NCDDD. Methods: Twenty-five patients with NCDDD received ACDR with a Prestige-LP prosthesis. Clinical outcomes were evaluated using the 36-Short Form (SF-36, Mental Component Summary [MCS] and Physical Component Summary [PCS]), Visual Analog Scale (VAS), Japanese Orthopedic Association (JOA), and Neck Disability Index (NDI) scores. Radiographic evaluations included cervical lordosis (CL), range of motion (ROM), and disc height (DH). Data regarding complications were collected as well. Results: The mean follow-up period was 32.24 months. Clinical outcomes, including SF-36 MCS and PCS, VAS, JOA, and NDI scores significantly improved at the 24-month follow-up (p < 0.05). There were no significant differences in CL and ROM at the 24-month follow-up (p > 0.05). Although there was a significant difference between the before and 3-month follow-up (p < 0.05), the ROM of the intermediate segment (IS) showed a tendency of returning to the preoperative state. The DH of the IS was maintained at each measurement while the DH of the upper and lower operated segments significantly increased at the 24-month follow-up (p < 0.05). One patient, whose prosthesis remained mobile at the last follow-up, showed evidence of heterotopic ossification (HO). Conclusion: ACDR with the Prestige-LP prosthesis is a safe and feasible alternative procedure for treatment of NCDDD. In the future, a large-sample, prospective randomized controlled study with long-term follow-up will be needed to further demonstrate noncontiguous ACDR as an optimal surgical option for NCDDD. (C) 2016 Elsevier B.V. All rights reserved.
Background: Postoperative limb positioning has been reported to be an efficient and simple way to reduce blood loss and improve range of motion following total knee arthroplasty (TKA). This meta-analysis was designed to compare the effectiveness of two different limb positions in primary TKA. Materials and methods: A meta-analysis of the PubMed, CENTRAL, Web of Science, EMBASE and Google Search Engine electronic databases was performed. In this meta-analysis, two postoperative limb positions were considered: mild-flexion (flexion less than 60 degrees) and high-flexion (flexion at 60 degrees or more). The subgroups were analysed using RevMan 5.3. Results: Nine RCTs were included with a total sample size of 913 patients. The mild- and high-flexion positions significantly reduced postoperative total blood loss (P = 0.04 and P = 0.01; respectively). Subgroup analysis indicated that knee flexion significantly reduced hidden blood loss when the knee was fixed in mild-flexion (P = 0.0004) and significantly reduced transfusion requirements (P = 0.03) and improved range of motion (ROM) (P < 0.00001) when the knee was fixed in high-flexion. However, the rates of wound-related infection, deep venous thrombosis (DVT) and pulmonary embolism (PE) did not significantly differ between the two flexion groups. Conclusion: This meta-analysis suggests that mild-and high-flexion positions have similar efficacy in reducing total blood loss. In addition, subgroup analysis indicates that the mild-flexion position is superior in decreasing hidden blood loss compared with high-flexion; the high-flexion position is superior to mild-flexion in reducing transfusion requirements and improving postoperative ROM. Thus, the use of the high-flexion position is a viable option to reduce blood loss in patients following primary TKA without increasing the risk of wound-related infection, DVT or PE. (C) 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.
Ischemia-induced stroke is the most common disease of the nervous system and is associated with a high mortality rate worldwide. Cerebral ischemia may lead to remote organ dysfunction, particular in the lungs, resulting in lung injury. Nowadays, bone marrow-derived mesenchymal stem cells (BMSCs) are widely studied in clinical trials as they may provide an effective solution to the treatment of neurological and cardiac diseases; however, the underlying molecular mechanisms remain unknown. In this study, a model of permanent focal cerebral ischemia-induced lung injury was successfully established and confirmed by neurological evaluation and lung injury scores. We demonstrated that the transplantation of BMSCs (passage 3) via the tail vein into the lung tissues attenuated lung injury. In order to elucidate the underlying molecular mechanisms, we analyzed the gene expression profiles in lung tissues from the rats with focal cerebral ischemia and transplanted with BMSCs using a Gene microarray. Moreover, the Gene Ontology database was employed to determine gene function. We found that the phosphoinositide 3-kinase (PI3K)-AKT signaling pathway, transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) were downregulated in the BMSC transplantation groups, compared with the control group. These results suggested that BMSC transplantation may attenuate lung injury following focal cerebral ischemia and that this effect is associated with the downregulation of TGF-beta, PDGF and the PI3K-AKT pathway.
Rationale: Ebstein anomaly is a common congenital heart disease that may induce severe tricuspid regurgitation and dilation of the "atrialized" portion of the right ventricle. Patients who undergo surgery to correct Ebstein anomaly are at high risk of postoperative right-sided heart failure, yet little is known about what pre-, peri-, or postoperative procedures may help reduce this risk. Patient concerns: Here, we describe 3 cases of adults with Ebstein anomaly who underwent corrective surgery and in whom right-sided heart failure occurred with severe tricuspid regurgitation detected by transesophageal echocardiography. Diagnoses: Ebstein anomaly. Intervention: Various approaches were applied to prevent right heart failure: perioperative control of atrial and ventricle arrhythmia, protection of myocardium, reduction of right-side cardiac workload after cardiopulmonary bypass, and mechanical support for right heart. Outcomes: One of the 3 patients died, another experienced kidney failure despite postoperative support on extracorporeal membrane oxygenation, and the third patient survived without complications. Lessons: Our case series suggests that surgical prognosis can be improved through aggressive preoperative treatment, vasoactive and anti-arrhythmia medications, and comprehensive measures designed to reduce myocardial injury, prevent myocardial edema, and reduce pre- and afterload on the right ventricle.