羟基红花黄色素A通过抑制程序性坏死减轻小鼠重症中暑引起的急性肺损伤

目的 研究羟基红花黄色素A（HSYA）是否在重症中暑肺损伤中起保护作用及其可能的作用机制。方法 使用不同浓度（1.125、2.25、4.5 mg/kg）HSYA腹腔注射预处理小鼠，建立重症中暑（sHS）小鼠模型，分为低、中、高剂量HSYA中暑组、单纯中暑组及正常对照组，12只/组。初步观察及比较各组热耐受的情况，以确定HSYA最佳治疗剂量；后使用中剂量HSYA及RIP1活化抑制剂Nec-1预处理小鼠，分组为HSYA+HS组、Nec-1+HS组、HS组及正常对照组，8只/组，观察72 h恢复期核心体温变化特征，比较热耐受情况及生存情况。给予相同处理因素处理小鼠分组为正常对照组，HS组，HSYA+HS组及Nec-1+HS组，正常对照组6只，其余18只/组，分别于重症中暑恢复期不同阶段（0、2、6、12、24 h）处死小鼠，每个时间点处死3只小鼠，收集小鼠的肺组织、肺泡灌洗液及血液样本，取肺组织行HE染色，并进行病理评分，检测肺湿干重比，肺含水量，肺泡灌洗液中白细胞、中性粒细胞、蛋白含量；ELISA法检测肺泡灌洗液中HMGB1水平及血清中TNF-α、IL-6及HMGB1水平；Western blotting检测恢复期（2、6、12 h）肺组织中RIP1、RIP3、MLKL-s358、MLKL表达水平，及经HSYA预处理后MLKL-s358蛋白水平。结果 中剂量及高剂量HSYA预处理可明显改善小鼠热耐受能力，中剂量与高剂量无显著差异，后续药物预处理以中剂量（2.25 mg/kg）作为标准剂量；与HS组相比，HSYA+HS组和Nec-1+HS组小鼠热耐受程度均增加（P<0.05），HSYA+HS组和Nec-1+HS组无明显差异。HSYA及Nec-1预处理组小鼠生存率增加（P<0.05），肺组织病理评分、TNF-α、IL-6及HMGB1水平降低（P<0.05），肺湿干重比，肺含水量，肺泡灌洗液中白细胞、中性粒细胞、蛋白含量及HMGB1水平降低（P<0.05），HS小鼠恢复期肺组织RIP1水平及MLKL-s358磷酸化水平升高（P<0.05），与HS组相比，HSYA+HS组MLKL-s358磷酸化水平降低。结论 重症中暑小鼠肺组织可发生程序性坏死，HSYA可通过抑制程序性坏死发挥肺保护作用。     

Stereotactic body radiotherapy for Stage I lung cancer with chronic obstructive pulmonary disease: special reference to survival and radiation-induced pneumonitis

This retrospective study aimed to evaluate radiation-induced pneumonitis (RIP) and a related condition that we define in this report—prolonged minimal RIP (pmRIP)—after stereotactic body radiotherapy (SBRT) for Stage I primary lung cancer in patients with chronic obstructive pulmonary disease (COPD). We assessed 136 Stage I lung cancer patients with COPD who underwent SBRT. Airflow limitation on spirometry was classified into four Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, with minor modifications: GOLD 1 (mild), GOLD 2 (moderate), GOLD 3 (severe) and GOLD 4 (very severe). On this basis, we defined two subgroups: COPD-free (COPD −) and COPD-positive (COPD +). There was no significant difference in overall survival or cause-specific–survival between these groups. Of the 136 patients, 44 (32%) had pmRIP. Multivariate analysis showed that COPD and the Brinkman index were statistically significant risk factors for the development of pmRIP. COPD and the Brinkman index were predictive factors for pmRIP, although our findings also indicate that SBRT can be tolerated in early lung cancer patients with COPD.     

Differential role of RIP1 in Smac mimetic-mediated chemosensitization of neuroblastoma cells

We explored the potential of Smac mimetics, which antagonize Inhibitor of Apoptosis (IAP) proteins, for chemosensitization of neuroblastoma (NB). Here, we report that Smac mimetics, e.g. BV6, prime NB cells for chemotherapeutics including the topoisomerase II inhibitor doxorubicin (DOX) and vinca alkaloids such as Vincristine (VCR), Vinblastine (VBL) and Vinorelbine (VNR). Additionally, BV6 acts in concert with DOX or VCR to suppress long-term clonogenic growth. While BV6 causes rapid downregulation of cellular IAP (cIAP)1 protein and nuclear factor-kappaB (NF-κB) activation, DOX/BV6- or VCR/BV6-induced apoptosis occurs independently of NF-κB or TNFα signaling, since overexpression of dominant-negative IκBα superrepressor or the Tumor Necrosis Factor (TNF)α-blocking antibody Enbrel fail to block cell death. Mechanistic studies reveal that Receptor-interacting protein (RIP)1 is required for DOX/BV6-, but not for VCR/BV6-induced apoptosis, since transient or stable knockdown of RIP1 or the pharmacological RIP1 inhibitor necrostatin-1 significantly reduce apoptosis. By comparison, VCR/BV6-mediated apoptosis critically depends on the mitochondrial pathway. VCR/BV6 cotreatment causes phosphorylation of BCL-2 during mitotic arrest, enhanced activation of BAX and BAK and loss of mitochondrial membrane potential (MMP). Additionally, overexpression of BCL-2 profoundly suppresses VCR/BV6-induced apoptosis. Thus, BV6 sensitizes NB cells to chemotherapy-induced apoptosis via distinct initial signaling mechanisms depending on the chemotherapeutic drug. These findings provide novel mechanistic insights into Smac mimetic-mediated chemosensitization of NB.     

阻断RIP2对小鼠巨噬细胞及内毒素血症的影响

目的:阻断RIP2对巨噬细胞产生炎症细胞因子及内毒素血症小鼠的影响。方法:构建小鼠RIP2基因的siRNA质粒,转染细胞后用RT-PCR和Western blot方法检测细胞RIP2的表达;LPS刺激后,用ELISA法测定细胞TNF-α,半定量West- ern blot测定HMGB1的水平。RIP2 siRNA质粒转染小鼠后,予LPS刺激小鼠,观察小鼠死亡率,用Western blot方法检测肝组织RIP2和HMGB1的表达,ELISA法测定血清TNF-α的水平。结果:RIP2 siRNAⅢ号质粒可阻断RIP2的mRNA和蛋白表达。LPS刺激后,阻断RIP2的细胞产生TNF-α、HMGB1减少;体内转染后,阻断RIP2的小鼠生存率较其它组高,肝组织中HMGB1的表达较其他组减少,血清TNF-α水平较其它组低。结论:RIP2 siRNAⅢ号质粒可阻断RIP2的表达,从而减少TNF-α、HMGB1等炎症细胞因子的产生,降低小鼠内毒素血症的死亡率。     

Two independent pathways of regulated necrosis mediate ischemia–reperfusion injury

Regulated necrosis (RN) may result from cyclophilin (Cyp)D-mediated mitochondrial permeability transition (MPT) and receptor-interacting protein kinase (RIPK)1-mediated necroptosis, but it is currently unclear whether there is one common pathway in which CypD and RIPK1 act in or whether separate RN pathways exist. Here, we demonstrate that necroptosis in ischemia–reperfusion injury (IRI) in mice occurs as primary organ damage, independent of the immune system, and that mice deficient for RIPK3, the essential downstream partner of RIPK1 in necroptosis, are protected from IRI. Protection of RIPK3-knockout mice was significantly stronger than of CypD-deficient mice. Mechanistically, in vivo analysis of cisplatin-induced acute kidney injury and hyperacute TNF-shock models in mice suggested the distinctness of CypD-mediated MPT from RIPK1/RIPK3-mediated necroptosis. We, therefore, generated CypD-RIPK3 double-deficient mice that are viable and fertile without an overt phenotype and that survived prolonged IRI, which was lethal to each single knockout. Combined application of the RIPK1 inhibitor necrostatin-1 and the MPT inhibitor sanglifehrin A confirmed the results with mutant mice. The data demonstrate the pathophysiological coexistence and corelevance of two separate pathways of RN in IRI and suggest that combination therapy targeting distinct RN pathways can be beneficial in the treatment of ischemic injury.     

Role of AMPK in pancreatic beta cell function

Pharmacological activation of AMP activated kinase (AMPK) by metformin has proven to be a beneficial therapeutic approach for the treatment of type II diabetes. Despite improved glucose regulation achieved by administration of small molecule activators of AMPK, the potential negative impact of enhanced AMPK activity on insulin secretion by the pancreatic beta cell is an important consideration. In this review, we discuss our current understanding of the role of AMPK in central functions of the pancreatic beta cell, including glucose-stimulated insulin secretion (GSIS), proliferation, and survival. In addition we discuss the controversy surrounding the role of AMPK in insulin secretion, underscoring the merits and caveats of methods used to date.     

Antiviral Activity of Ribosome-Inactivating Proteins

Ribosome-inactivating proteins (RIPs) are rRNA N-glycosylases from plants (EC 3.2.2.22) that inactivate ribosomes thus inhibiting protein synthesis. The antiviral properties of RIPs have been investigated for more than four decades. However, interest in these proteins is rising due to the emergence of infectious diseases caused by new viruses and the difficulty in treating viral infections. On the other hand, there is a growing need to control crop diseases without resorting to the use of phytosanitary products which are very harmful to the environment and in this respect, RIPs have been shown as a promising tool that can be used to obtain transgenic plants resistant to viruses. The way in which RIPs exert their antiviral effect continues to be the subject of intense research and several mechanisms of action have been proposed. The purpose of this review is to examine the research studies that deal with this matter, placing special emphasis on the most recent findings.