Two sphingomyelin synthase homologues regulate body weight and sphingomyelin synthesis in female brown planthopper,N. lugens (Stål)

Although sphingomyelins known to be are lipid constituents of the plasma membrane in vertebrates, much remains obscure about the metabolism of sphingomyelins in insects. With ultra performance liquid chromatography‐time‐of‐flight‐tandem mass spectrometry analysis, we revealed for the first time that sphingomyelins are abundant in Nilaparvata lugens (Stål), the brown planthopper (BPH), and their biosynthesis is carried out by sphingomyelin synthase‐like protein 2 (SMSL2), which is homologous to sphingomyelin synthase‐related protein (SMSr). Unlike other insect species, high concentrations of sphingomyelins rather than ceramide phosphoethanolamines exist in the BPH. Two putative genes, which are homologous to SMSr, are named Nilaparvata lugens SMS‐like 1 (NlSMSL1) and 2 (NlSMSL2). Knockdowns of both NlSMSL2 and NlSMSL1 were conducted but only the first decreased concentrations of sphingomyelins in the BPH, indicating that NlSMSL2 plays a role in the biosynthesis of sphingomyelins. Real‐time quantitative PCR analysis revealed both NlSMSL1 and NlSMSL2 are highly expressed in BPH adults, with NlSMSL1 specifically highly expressed in reproductive organs (ovaries and testes) whereas NlSMSL2 was highly expressed in the malpighian tubules. The knockdown of NlSMSL1 or NlSMSL2 increased BPH female body weight but not that of males, suggesting sex‐specific roles for SMSLs in influencing BPH body weight. The results suggest that NlSMSL2 catalyses the synthesis of sphingomyelins and maintains female BPH body weight through alteration of sphingolipid content.     

单甲基亚砷酸联合隐丹参酮抑制多发性骨髓瘤U266增殖的作用机制研究

摘要 目的：研究单甲基亚砷酸(MMAIII)联合隐丹参酮(CPT)对多发性骨髓瘤U266的协同抑制效应，阐明其诱导多发性骨髓瘤凋亡的作用机制。方法：cell-counting-kit-8(CCK8)法检测细胞存活率；AnnexinⅤ-FITC/PI流式细胞术检测细胞凋亡；Western Blot检测凋亡标记蛋白PARP的总蛋白和剪切表达水平；酶标仪检测酸性鞘磷脂酶活性；免疫荧光技术检测细胞膜神经酰胺和脂筏标记物。结果：CCK8结果显示隐丹参酮浓度为15μM时细胞存活率为80.9%±5.4%(24h)、60%±8.4%(48h)，单甲基亚砷酸浓度为1μM时细胞存活率为82.5%±5.8%(24h)、67.7%+9.7%(48h)，隐丹参酮（15μM）联合单甲基亚砷酸（1μM）作用U266细胞24h、48h后细胞存活率为29.1%±7.0%(24h)、18%±2.7%(48h)；流式细胞术结果显示联合用药组细胞凋亡率为41.7%±4.4%、单甲基亚砷酸组为10.6%±4.0%、隐丹参酮组为10.5%±3.0%；Western Blot显示联合作用组凋亡蛋白PARP剪切活化水平较单甲基亚砷酸单药组及隐丹参酮单药组有显著升高；酸性鞘磷脂酶活性测定结果显示联合用药组上调多发性骨髓瘤U266细胞酸性鞘磷脂的活性；免疫荧光技术检测结果显示联合用药后U266细胞膜上荧光强度增加，加入Filipin后荧光强度较联合用药减少。结论：MMAIII与CPT协同作用能诱导人多发性骨髓瘤U266细胞凋亡发生，其作用机制主要与促进细胞膜鞘磷脂水解生成神经酰胺、诱导脂筏聚集促进凋亡相关蛋白剪切活化密切相关。     

Selective induction of apoptosis in MCF7 cancer-cell by targeted liposomes functionalised with mannose-6-phosphate

Liposomes are versatile platforms to carry anticancer drugs in targeted drug delivery; they can be surface modified by different strategies and, when coupled with targeting ligands, are able to increase cellular internalisation and organelle-specific drug delivery. An interesting strategy of antitumoral therapy could involve the use of lysosomotropic ligand-targeted liposomes loaded with molecules, which can induce lysosomal membrane permeabilization (LMP), leakage of cathepsins into the cytoplasm and subsequent apoptosis. We have previously demonstrated the ability of liposomes functionalised with a mannose-6-phosphate to reach lysosomes; in this research we compare the behaviour of M6P-modified and non-functionalised liposomes in MCF7 tumour cell and in HDF normal cells. With this aim, we first demonstrated by Western blotting the overexpression of mannose-6-phosphate/insulin-like growth factor (M6P/IGF-II) receptor in MCF7. Then, we prepared calcein-loaded liposomes and we revealed the increased uptake of M6P-functionalised liposomes in MCF7 cells respect to HDF cells by flow cytometry analysis. Finally, we loaded functionalised and not functionalised liposomes with N-hexanoyl-d-erythro-sphingosine (C6Cer), able to initiate LMP-induced apoptosis; after having studied the stability of both vesicles in the presence of serum by Dynamic Light Scattering and Spectrophotometric turbidity measurements, we showed that ceramide-loaded M6P-liposomes significantly increased apoptosis in MCF7 with respect to HDF cells.     

自然杀伤T细胞失能的相关研究进展

自然杀伤T细胞同时表达自然杀伤细胞和T细胞受体,发挥免疫调节和细胞毒作用.相关研究证实激活自然杀伤T细胞可以抑制肿瘤进展,但短暂活化的自然杀伤T细胞常常因为未知原因迅速进入失活状态.本文就目前自然杀伤T细胞失能可能机制及应对措施的研究进展作一综述.     

Cutis laxa,exocrine pancreatic insufficiency and altered cellular metabolomics as additional symptoms in a new patient with ATP6AP1-CDG

Congenital disorders of glycosylation (CDG) are genetic defects in the glycoconjugate biosynthesis. > 100 types of CDG are known, most of them cause multi-organ diseases. Here we describe a boy whose leading symptoms comprise cutis laxa, pancreatic insufficiency and hepatosplenomegaly. Whole exome sequencing identified the novel hemizygous mutation c.542 T > G (p.L181R) in the X-linked ATP6AP1, an accessory protein of the mammalian vacuolar H⁺-ATPase, which led to a general N-glycosylation deficiency. Studies of serum N-glycans revealed reduction of complex sialylated and appearance of truncated diantennary structures. Proliferation of the patient's fibroblasts was significantly reduced and doubling time prolonged. Additionally, there were alterations in the fibroblasts' amino acid levels and the acylcarnitine composition. Especially, short-chain species were reduced, whereas several medium- to long-chain acylcarnitines (C14-OH to C18) were elevated. Investigation of the main lipid classes revealed that total cholesterol was significantly enriched in the patient's fibroblasts at the expense of phophatidylcholine and phosphatidylethanolamine. Within the minor lipid species, hexosylceramide was reduced, while its immediate precursor ceramide was increased. Since catalase activity and ACOX3 expression in peroxisomes were reduced, we assume an ATP6AP1-dependent impact on the β-oxidation of fatty acids. These results help to understand the complex clinical characteristics of this new patient.     

鞘磷脂类信号通路与动脉粥样硬化的研究进展

动脉粥样硬化是临床常见的冠心病和脑梗死等缺血性心脑血管疾病的主要病理基础,其病因复杂,发病机制尚未完全阐明。近年来,越来越多的研究显示鞘磷脂类信号通路可通过调节脂代谢、炎症和血管内皮功能等影响动脉粥样硬化的发生发展。文章综述了鞘磷脂类信号通路关键分子鞘磷脂、神经酰胺和1-磷酸鞘氨醇与动脉粥样硬化的关系,旨在为防治疾病提供新思路。     

Acetaminophen‐induced hepatocyte injury: C2‐ceramide and oltipraz intervention,hepatocyte nuclear factor 1 and glutathione S‐transferase A1 changes

Acetaminophen (APAP) is an antipyretic and analgesic, which is commonly associated with drug‐induced hepatic injury. C2‐ceramide plays a key role in mediating cell life activities, and oltipraz was extensively studied as a cancer chemopreventive agent. Glutathione S‐transferase A1 (GSTA1) acts as a vital liver detoxification enzyme. Hepatocyte nuclear factor 1 (HNF‐1) regulates various cellular signaling pathways. In this study, we investigated the effects of C2‐ceramide and oltipraz on APAP‐induced hepatocyte injury and the changes of HNF‐1 and GSTA1. Results showed that C2‐ceramide (6 μmol/L) exacerbated APAP‐induced hepatocyte injury and caused a significant decrease (P < .01) in HNF‐1 and GSTA1 expressions. Meanwhile, GSTA1 content in supernatant was significantly increased (P < .01). In contrast, oltipraz (8 μmol/L) reduced the injury and significantly elevated (P < .01) HNF‐1 and GSTA1 expressions while GSTA1 content in supernatant was significantly decreased (P < .01). In conclusion, these findings revealed that C2‐ceramide inhibited HNF‐1 and GSTA1 expression and exacerbated hepatocyte injury, while oltipraz treatment results in the reduction of hepatocyte injury, and promoted HNF‐1 and GSTA1 expression. Additionally, the changes in HNF‐1 and GSTA1 were related to APAP‐induced hepatocyte injury. These results were useful to investigate the mechanism of an antipyretic and analgesic drug combination.