虹鳟LECT2的酵母表达、纯化及生物活性分析

白细胞衍生趋化因子2 (leukocyte cell-derived chemotaxin 2,LECT2)是一个参与多种生理和病理过程的分泌型细胞因子.该文采用毕赤酵母表达体系分泌表达虹鳟LECT2,用阳离子交换柱结合分子筛层析方法分离纯化目的蛋白,并获得纯度为96％,得率为120 mg/L的重组虹鳟(Oncorhynchus mykiss)LECT2酵母培养物.生物学活性验证表明该重组蛋白能趋化虹鳟头肾来源的巨噬细胞,增强其呼吸爆发和杀菌能力,并改变其细胞因子等基因的表达.综上,该实验建立了一种快速有效的虹鳟LECT2活性重组蛋白的制备方法,为后续相关蛋白的功能研究奠定了基础.     

脂酰辅酶A长链合成酶3及其相关疾病

脂滴(lipid droplets)是细胞内脂质贮存和调节细胞脂质稳态的重要细胞器,其表面具有多种脂滴相关蛋白质。长链酰基辅酶A合成酶家族的成员脂酰辅酶A长链合成酶3(acyl CoA long chain synthetase 3,ACSL3)即脂滴相关蛋白质的一种,也是生物合成过程中必需的酶之一。ACSL3广泛分布于大多数细胞中的脂滴表面,其在脂滴的合成、自噬的调节和细胞铁死亡等多种病理生理过程中发挥着不同的作用。此外,多项研究表明,ACSL3还广泛参与到多种疾病的发生发展,包括动脉粥样硬化、非酒精性脂肪肝病、糖尿病和肿瘤等。当前,国内对ACSL3的研究相对集中于ACSL3与动物育种和生长的关系,而对ACSL3在脂质代谢中的作用机制及其与疾病的关系鲜有报道。本文基于国内外对ACSL3的研究,对该基因的结构、在细胞脂代谢中的作用机制及其相关疾病进行归纳,进一步探究ACSL3在脂滴的合成、自噬、铁死亡过程中的作用,为防治动脉粥样硬化、非酒精性脂肪肝病、糖尿病(glucose)等多种ACSL3相关疾病提供新的理论依据。     

单核细胞趋化蛋白受体的研究进展

单核细胞趋化蛋白及其受体在机体免疫应答中(免疫调节、器官形成、调节造血和神经元通讯)发挥了重要作用,同时也广泛参与某些疾病的发病机制(动脉粥样硬化、感染炎症性疾病及肿瘤等)。因此,有关趋化性细胞因子的新理论和技术可为临床治疗某些疾病提供了新思路。本文简要地综述单核细胞趋化蛋白受体的生物学特性、生物学作用及对心血管疾病的影响作用。     

β-arrestin2在心血管疾病中的研究进展

β-抑制蛋白2(β-arrestin2)是一类具有多种生物学功能的细胞内蛋白质，不仅能够通过与G蛋白竞争性结合G蛋白偶联受体(G protein-coupled receptor,GPCR)从而负性调控GPCR信号通路，还可通过G蛋白非依赖性途径参与调节多种信号转导通路，对心血管系统的稳定至关重要。此外，β-arrestin2异常的表达与高血压、心力衰竭、心肌缺血再灌注损伤、心室重塑、动脉粥样硬化以及动脉瘤等多种疾病密切相关。因此，本文就β-arrestin2在心血管疾病领域的研究进展进行综述，阐述β-arrestin2结构、功能及其在炎症反应、细胞代谢中的作用和相关分子机制，以期为心血管疾病诊治提供新的思路。     

金属硫蛋白及其生物学功能

金属硫蛋白(metallothionein, MT) 是一类富含半胱氨酸的低分子质量蛋白质,已鉴定4种亚型：MT-1、MT-2、MT-3和MT-4,基于各亚型功能的相对异质性而使MT呈现其生物学作用的多样性。金属硫蛋白通过与金属离子结合而参与基因表达调控和机体的重金属解毒过程;金属硫蛋白通过抑制多种氧化应激途径而保护细胞免受损伤;金属硫蛋白通过参与细胞的增殖、分化和凋亡的调节而影响肿瘤及其他重大疾病的发生发展。本文在金属硫蛋白的结构和分类的基础上综述其生物学作用及其相关机制。     

支链氨基酸代谢及其与疾病的关系

亮氨酸、异亮氨酸和缬氨酸的疏水侧链都具有分支的甲基基团，因而被统称为支链氨基酸(branched chain amino acids, BCAAs)。作为机体的必需氨基酸，除了作为蛋白质合成的基本原料，BCAAs及其各种分解代谢产物还可以作为信号分子，调控从蛋白质合成到胰岛素分泌等众多生理过程。因此，它们的正常代谢对机体生命活动至关重要。越来越多的证据表明，BCAAs代谢异常与多种疾病关系密切，包括枫糖尿病、神经系统疾病、糖尿病、心血管疾病、肝疾病和癌症等。本文详细概述了哺乳动物中BCAAs分解代谢的基本模式、调控机制(主要关注对2个关键代谢酶BCAT和BCKDH的调控)以及BCAAs参与mTOR和AMPK信号通路在机体代谢中发挥的作用。总结了BCAAs代谢异常与多种疾病的关系，并对有关的矛盾观点进行阐述和解释。近年来，BCAAs代谢及调控在疾病发生发展中的作用成为研究热点，为相关疾病预防和治疗提供了新视角。本综述将为进一步研究提供线索。     

LARC：双重角色的趋化蛋白

趋化蛋白是 80年代末继细胞因子后引起广泛关注的一大类结构相似、功能相近的小分子蛋白质。近年来 ,随着其家族成员的不断壮大 ,对其结构、功能等的认识也不断深入。目前已克隆到上百个趋化蛋白分子 ,依照各自Ｎ末端半胱氨酸 (Ｃｙｓ)模体的不同 ,可将其分为 4类或者称 4个亚家族 ,分别是α趋化蛋白 (ＣＸＣ趋化蛋白 )、β趋化蛋白 (ＣＣ趋化蛋白 )、γ趋化蛋白 (Ｃ趋化蛋白 )和δ趋化蛋白 (ＣＸ3 Ｃ趋化蛋白 ) [1] 。趋化蛋白被称为细胞内信使 ,在多种生理或病理反应中均扮演着重要的角色 ,已明确的有 :参与先天性及后天性免疫应答 ;造血…     

长链非编码RNA与缺血缺氧性疾病的研究进展

长链非编码RNA(long non-coding RNA,lnc RNA)是指转录本长度超过200 nt的不编码蛋白质的RNA。lnc RNA在细胞增殖分化、个体发育、干细胞活性与代谢等几乎所有重要生命活动中发挥关键的调控作用,与多种疾病的发生密切相关。近年研究表明,lnc RNA在多种器官缺血缺氧的发生及恢复中发挥着重要的作用。现探讨lnc RNA在缺血缺氧性疾病中的调控机制,重点介绍lnc RNA与缺血性脑卒中和缺血性心脏病的关系,以期为缺血缺氧相关心脑血管疾病的早期预防、诊断和治疗提供新策略。     

mTOR信号通路在疾病中的作用与调控机制

mTOR是一种丝氨酸/苏氨酸蛋白激酶,与不同的蛋白质结合形成mTORC1和mTORC2两种复合物,体现了结构和功能上的差异。mTOR信号通路参与多种生理和病理过程,不仅可以调节细胞生长、代谢、血管生成、内环境稳定、自噬和衰老等生理过程,还与多种恶性肿瘤、自身免疫性疾病、心脑血管疾病等一系列的疾病发生及肿瘤抗药性相关。该文综述了mTOR信号通路在疾病发生中的作用及调控机制,为疾病治疗提供参考。     

Molecular cloning of leukocyte cell-derived chemotaxin 2 in rainbow trout

In humans, leukocyte cell-derived chemotaxin 2 (LECT2) is a 16kDa chemotactic protein that consists of 133 amino acids and three intramolecular disulphide bonds. Although it was originally demonstrated to have a chemotactic function in vitro, recent data sustain a further multifunctional role of LECT2 that extends from cell growth, differentiation, damage/repair process and carcinogenesis to autoimmune diseases. The in vivo function of LECT2 protein still remains obscure. In order to study the phylogeny of LECT2, a full-length cDNA clone of LECT2 gene, 720 bp in size, was isolated in rainbow trout (Oncorhynchus mykiss). Its deduced amino acid sequence of 156 residues, presents 40, 45 and 61% overall identity to human, mouse and carp LECT2 proteins, respectively. In contrast to mammalian LECT2 protein, trout LECT2 protein reveals two potential N-glycosylation sites. Phylogenetic analysis shows that trout LECT2 is clustered with the known homologous proteins. Trout LECT2 mRNA is predominately expressed in liver and spleen, showing lower expression in kidney, intestine, heart and brain.     

LECT2: A pleiotropic and promising hepatokine,from bench to bedside

LECT2 (leucocyte cell‐derived chemotaxin 2) is a 16‐kDa protein mainly produced by hepatocytes. It was first isolated in PHA‐activated human T‐cell leukaemia SKW‐3 cells and originally identified as a novel neutrophil chemotactic factor. However, many lines of studies suggested that LECT2 was a pleiotropic protein, it not only functioned as a cytokine to exhibit chemotactic property, but also played multifunctional roles in some physiological conditions and pathological abnormalities, involving liver regeneration, neuronal development, HSC(haematopoietic stem cells) homeostasis, liver injury, liver fibrosis, hepatocellular carcinoma, metabolic disorders, inflammatory arthritides, systemic sepsis and systemic amyloidosis. Among the above studies, it was discovered that LECT2 could be a promising molecular biomarker and therapeutic target. This review summarizes LECT2‐related receptors and pathways, basic and clinical researches, primarily in mice and human, for a better comprehension and management of these diseases in the future.     

Increase in hepatic NKT cells in leukocyte cell-derived chemotaxin 2-deficient mice contributes to severe concanavalin A-induced hepatitis

Leukocyte cell-derived chemotaxin 2 (LECT2) was originally identified for its possible chemotactic activity against human neutrophils in vitro. It is a 16-kDa protein that is preferentially expressed in the liver. Its homologues have been widely identified in many vertebrates. Current evidence suggests that LECT2 may be a multifunctional protein like cytokines. However, the function of LECT2 in vivo remains unclear. To elucidate the role of this protein in vivo, we have generated LECT2-deficient (LECT2(-/-)) mice. We found that the proportion of NKT cells in the liver increased significantly in LECT2(-/-) mice, although those of conventional T cells, NK cells, and other cell types were comparable with those in wild-type mice. Consistent with increased hepatic NKT cell number, the production of IL-4 and IFN-gamma was augmented in LECT2(-/-) mice upon stimulation with alpha-galactosylceramide, which specifically activates Valpha14 NKT cells. In addition, NKT cell-mediated cytotoxic activity against syngeneic thymocytes increased in hepatic mononuclear cells obtained from LECT2(-/-) mice in vitro. Interestingly, the hepatic injury was exacerbated in LECT2(-/-) mice upon treatment with Con A, possibly because of the significantly higher expression of IL-4 and Fas ligand. These results suggest that LECT2 might regulate the homeostasis of NKT cells in the liver and might be involved in the pathogenesis of hepatitis.     

Alleviation of lipopolysaccharide/d-galactosamine-induced liver injury in leukocyte cell-derived chemotaxin 2 deficient mice

Leukocyte cell-derived chemotaxin 2 (LECT2) is a secreted pleiotropic protein that is mainly produced by the liver. We have previously shown that LECT2 plays an important role in the pathogenesis of inflammatory liver diseases. Lipopolysaccharide/d-galactosamine (LPS/d-GalN)-induced acute liver injury is a known animal model of fulminant hepatic failure. Here we found that this hepatic injury was alleviated in LECT2-deficient mice. The levels of TNF-α and IFN-γ, which mediate this hepatitis, had significantly decreased in these mice, with the decrease in IFN-γ production notably greater than that in TNF-α. We therefore analyzed IFN-γ-producing cells in liver mononuclear cells. Flow cytometric analysis showed significantly reduced IFN-γ production in hepatic NK and NKT cells in LECT2-deficient mice compared with in wild-type mice. We also demonstrated a decrease in IFN-γ production in LECT2-deficient mice after systemic administration of recombinant IL-12, which is known to induce IFN-γ in NK and NKT cells. These results indicate that a decrease of IFN-γ production in NK and NKT cells was involved in the alleviation of LPS/d-GalN-induced liver injury in LECT2-deficient mice.     

Plasma leukocyte cell-derived chemotaxin 2 is associated with the severity of systemic inflammation in patients with sepsis

The aim of the present study was to determine the correlations between leukocyte cell-derived chemotaxin 2 (LECT2) and inflammation-related variables in human inflammatory disease. Plasma samples from 23 septic patients who had been admitted to the intensive care unit (ICU) of our institution and 31 volunteers were used. Plasma LECT2 concentrations were examined retrospectively and compared with those of various inflammatory cytokines and routine laboratory data. The LECT2 concentrations of the septic patients at the time of ICU entry (5.3 ± 4.1 ng/mL) were significantly lower than those of the volunteers (19.7 ± 3.4 ng/mL) and these concentrations had significantly increased by the time of ICU discharge. Individual analyses showed that the LECT2 concentrations of all 19 patients had increased by the time of ICU discharge. A combination of LECT2 and C-reactive protein (CRP) concentrations was capable of discriminating the acute and recovery phases of sepsis to a degree similar to those of the combinations of CRP concentration and percentage of neutrophils, CRP concentration and percentage of immature white blood cells, or CRP and interleukin-6 concentrations. Thus, the LECT2 concentration correlates with the severity of systemic inflammation in patients with sepsis. LECT2 may be a reliable diagnostic indicator of human inflammatory diseases.     

Molecular cloning of leucocyte cell-derived chemotaxin-2 gene in croceine croaker (Pseudosciaena crocea)

Leucocyte cell-derived chemotaxin-2 (LECT2) was originally demonstrated to have a chemotactic activity against human neutrophils in vitro. Current evidence suggests that LECT2 may be a multifunctional protein involved in cell growth, differentiation and autoimmune. A full-length cDNA clone of the LECT2 gene, 595bp in size, was isolated from the fish croceine croaker (Pseudosciaena crocea). It's 3'-UTR was much shorter (112nts) than that of trout LECT2 gene (210nts). Its deduced amino acid sequence of 151 residues had 39.7-75.5% identity to that of other animals. Phylogenetic analysis shows that croceine croaker LECT2 (pLECT2) is clustered tightly with other fish LECT2. The relationships of the different LECT2 coincided well with the evolutionary relationships of their organisms. In healthy fish, the expression levels of pLECT2 gene from different tissues were similar, while that in Vibrio alginolyticus-infected fish were significantly increased in liver and spleen comparing to those in healthy fish, and were a little higher in the other tissues.     

绝经后骨质疏松症患者血清LECT2水平的临床意义及其预测价值分析

摘要 目的：探讨绝经后骨质疏松症患者血清白细胞衍生趋化因子2（LECT2）水平的临床意义及其预测价值。方法：选择2020年1月～2022年1月湖南师范大学第一附属医院收治的绝经后骨质疏松症患者125例作为研究组,另选取同期体检的绝经后健康女性志愿者120例作为对照组。比较两组血清LECT2水平,并分析血清LECT2水平与腰椎和股骨颈骨密度（BMD）及骨代谢相关指标的相关性;应用受试者工作特征（ROC）曲线分析血清LECT2对绝经后骨质疏松症患者的预测价值。结果：研究组血清LECT2、骨钙素（OC）、I型原胶原N端前肽（PINP）、 I型胶原交联C末端肽（S-CTX）显著高于对照组,腰椎和股骨颈BMD显著低于对照组（P<0.05）。Pearson相关分析显示,绝经后骨质疏松症患者血清LECT2水平与OC、PINP、S-CTX水平呈正相关（P<0.05）,与腰椎和股骨颈BMD呈负相关（P<0.05）。ROC曲线分析显示,血清LECT2、OC、PINP、S-CTX联合检验对绝经后骨质疏松症患者的预测价值的曲线下面积（AUC）为0.856,大于各单一指标预测。结论：绝经后骨质疏松症女性血清LECT2水平升高,其水平与骨代谢指标OC、PINP、S-CTX水平呈正相关,与腰椎BMD和股骨颈BMD呈负相关,血清LECT2联合OC、PINP、S-CTX对绝经后骨质疏松症患者的预测价值较高。