Low-density lipoprotein receptor-related protein 2(LRP2)is required for lipid export in the midgut of the migratory locust,Locusta migratoria

Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholesterol-containing apolipoproteins to maintain lipid homeostasis.However,little is known about the role of LRP2 in lipid homeostasis in insects.In the present study,we investigated the function of LRP2 in the migratory locust Locusta migratoria(LmLRP2).The mRNA of LmLRP2 is widely distributed in various tissues,including integument,wing pads,foregut,midgut,hindgut,Malpighian tubules and fat body,and the amounts of LmLRP2 transcripts decreased gradually in the early stages and then increased in the late stages before ecdysis during the nymphal developmental stage.Fluorescence immunohistochemistry revealed that the LmLRP2 protein is mainly located in cellular membranes of the midgut and hindgut.Using RNAi to silence LmLRP2 caused molting defects in nymphs(more than 60%),and the neutral lipid was found to accumulate in the midgut and surface of the integument,but not in the fat body,of dsLmLRP2-treated nymphs.The results of a lipidomics analysis showed that the main components of lipids(diglyceride and triglyceride)were significantly increased in the midgut,but decreased in the fat body and hemolymph.Furthermore,the content of total triglyceride was significantly increased in the midgut,but markedly decreased in the fat body and hemolymph in dsLmLRP2-injected nymphs.Our results indicate that LmLRP2 is located in the cellular membranes of midgut cells,and is required for lipid export from the midgut to the hemolymphand fat body in locusts.

Association between Low-density Lipoprotein Receptor-related Protein 5 Polymorphisms and Type 2 Diabetes Mellitus in Han Chinese:a Case-control Study

Objective To investigate the association between low-density lipoprotein receptor-related protein 5 （LRPS） variants （rs12363572 and rs4930588） and type 2 diabetes mellitus （T2DM） in Han Chinese. Methods A total of 1842 T2DM cases （507 newly diagnosed cases and 1335 previously diagnosed cases） and 7777 controls were included in this case-control study. PCR-RFLP was conducted to detect the genotype of the two single nucleotide polymorphisms （SNPs）. Odds ratios （ORs） and 95% confidence intervals （95% CIs） were calculated to describe the strength of the association by logistic regression. Results In the study subjects, neither rs12363572 nor rs4930588 was significantly associated with T2DM, even after adjusting for relevant covariates. When stratified by body mass index （BMI）, the two SNPs were also not associated with T2DM. Among the 3 common haplotypes, only haplotype ~ was associated with reduced risk of T2DM （OR 0.820, 95% CI 0.732-0.919）. In addition, rs12363572 was associated with BMI （P〈0.001） and rs4930588 was associated with triglyceride levels （P=0.043） in 507 newly diagnosed T2DM cases but not in healthy controls. Conclusion No LRP5 variant was found to be associated with T2DM in Han Chinese, but haplotype TT was found to be associated with T2DM.

C1q/TNF-related protein 5 promotes atherogenesis by enhancing transcytosis and oxidative modification of low-density lipoprotein through increasing 12/15-lipoxygenase

Objective Increased transcytosis of low-density lipoprotein (LDL)across the endothelium and oxidation of LDL deposited within the subendothelial space are crucial early events in atherogenesis. C1q/TNF-related protein (CTRP) 5 is a novel secreted glycoprotein and its biological functions are largely undefined.

Roles of low?density lipoproteinreceptor?related protein 1 in tumors

Low-density lipoprotein receptor-related protein 1(LRP1,also known as CD91),a multifunctional endocytic and cell signaling receptor,is widely expressed on the surface of multiple cell types such as hepatocytes,fibroblasts,neurons,astrocytes,macrophages,smooth muscle cells,and malignant cells.Emerging in vitro and in vivo evidence demonstrates that LRP1 is critically involved in many processes that drive tumorigenesis and tumor progression.For example,LRP1 not only promotes tumor cell migration and invasion by regulating matrix metalloproteinase(MMP)-2and MMP-9 expression and functions but also inhibits cell apoptosis by regulating the insulin receptor,the serine/threonine protein kinase signaling pathway,and the expression of Caspase-3.LRPI-mediated phosphorylation of the extracellular signal-regulated kinase pathway and c-jun N-terminal kinase are also involved in tumor cell proliferation and invasion.In addition,LRP1 has been shown to be down-regulated by microRNA-205 and methylation of LRP1CpG islands.Furthermore,a novel fusion gene,LRP1-SNRNP25,promotes osteosarcoma cell invasion and migration.Only by understanding the mechanisms of these effects can we develop novel diagnostic and therapeutic strategies for cancers mediated by LRP1.

Low-density lipoprotein receptor-related protein 1 is a CROPs-associated receptor for Clostridioides infection toxin B

As the leading cause of worldwide hospital-acquired infection,Clostridioides difficile(C.difficile)infection has caused heavy economic and hospitalized burden,while its pathogenesis is not fully understood.Toxin B(Tcd B)is one of the major virulent factors of C.difficile.Recently,CSPG4 and FZD2 were reported to be the receptors that mediate Tcd B cellular entry.However,genetic ablation of genes encoding these receptors failed to completely block Tcd B entry,implicating the existence of alternative receptor(s)for this toxin.Here,by employing the CRISPR-Cas9 screen in CSPG4-deficient He La cells,we identified LDL receptor-related protein-1(LRP1)as a novel receptor for Tcd B.Knockout of LRP1 in both CSPG4-deficient He La cells and colonic epithelium Caco2 cells conferred cells with increased Tcd B resistance,while LRP1 overexpression sensitized cells to Tcd B at a low concentration.Co-immunoprecipitation assay showed that LRP1 interacts with full-length Tcd B.Moreover,CROPs domain,which is dispensable for Tcd B’s interaction with CSPG4 and FZD2,is sufficient for binding to LRP1.As such,our study provided evidence for a novel mechanism of Tcd B entry and suggested potential therapeutic targets for treating C.difficile infection.

Lack of Association of Common Polymorphism of LRP1 Gene with Myocardial Infarction in a Chinese Han Population

This study examined the association of a common polymorphic allele（25G） of the low-density lipoprotein receptor-related protein1（LRP1） gene with myocardial infarction（MI）.The genotypes of LRP1 25CG（rs35282763） were determined in 347 MI patients and 347 age-and sex-frequency-matched controls from an unrelated Chinese Han population.Factor Ⅷ（FⅧ） levels were measured in the MI patients and controls by chromogenic assay and enzyme-linked immunosor-bent assay（ELISA）.The results showed that LRP1 25CG（rs35282763） genotype distribution did not differ significantly between patients（n=206 for 25CC,n=122 for 25CG） and controls（n=191 for 25CC,n=126 for 25CG;P0.05）.The 25G allele was not associated with a reduced risk of MI（P0.05）.Further stratifications for age,sex,and other cardiovascular risk factors did not affect the negative findings.It was concluded that the presence of the G allele at the 25CG（rs35282763） polymorphism of the LRP1 is not associated with a reduced risk of MI,and genotyping for LRP1 25CG（rs35282763） polymor-phism is not useful in assessing the individual risk of MI.

急性冠脉综合征患者血清COMP、sST2及sLRP-1变化及与冠脉病变的相关性分析

目的探讨急性冠脉综合征患者血清软骨寡聚基质蛋白(COMP)、可溶性生长刺激表达基因2(sST2)、可溶性低密度脂蛋白受体相关蛋白1(sLRP-1)变化及与冠状动脉(冠脉)病变的相关性。方法选择2020年1月至2022年1月于青岛市市立医院治疗的120例急性冠脉综合征患者作为病例组,并选择我院同期体检的健康人群100例作为对照组,分析两组COMP、sST2及sLRP-1水平变化及与冠脉病变程度的相关性。结果病例组患者血清COMP、sST2及sLRP-1显著高于对照组,差异有统计学意义(P<0.05);轻度组(Gensini评分<50分)COMP、sST2及sLRP-1显著低于中度组(Gensini评分50~90分)和重度组(Gensini评分>90分),且中度组血清COMP、sST2及sLRP-1显著低于重度组,差异有统计学意义(P<0.05);预后不良组血清COMP、sST2及sLRP-1较预后良好组更高,差异有统计学意义(P<0.05);相关性分析显示,血清COMP、sST2及sLRP-1均与冠脉病变程度之间呈正相关(P<0.05)。结论血清COMP、sST2及sLRP-1在急性冠脉综合征患者中均呈高表达,且与冠脉病变程度关系密切,对于控制病情具有重要意义。

Liver as a new target organ in Alzheimer's disease:insight from cholesterol metabolism and its role in amyloid-beta clearance

Alzheimer's disease,the primary cause of dementia,is characterized by neuropathologies,such as amyloid plaques,synaptic and neuronal degeneration,and neurofibrillary tangles.Although amyloid plaques are the primary characteristic of Alzheimer's disease in the central nervous system and peripheral organs,targeting amyloid-beta clearance in the central nervous system has shown limited clinical efficacy in Alzheimer's disease treatment.Metabolic abnormalities are commonly observed in patients with Alzheimer's disease.The liver is the primary peripheral organ involved in amyloid-beta metabolism,playing a crucial role in the pathophysiology of Alzheimer's disease.Notably,impaired cholesterol metabolism in the liver may exacerbate the development of Alzheimer's disease.In this review,we explore the underlying causes of Alzheimer's disease and elucidate the role of the liver in amyloid-beta clearance and cholesterol metabolism.Furthermore,we propose that restoring normal cholesterol metabolism in the liver could represent a promising therapeutic strategy for addressing Alzheimer's disease.

低密度脂蛋白受体相关蛋白1基因多态性与中国人阿尔茨海默病发病风险的meta分析

目的探讨低密度脂蛋白受体相关蛋白1(LRP-1)基因C766T位点多态与中国人阿尔茨海默病(AD)发病风险的关系.方法应用LRP-1、low density lipoprotein receptor related protein 1 gene、阿尔茨海默病等关键词,检索中国期刊全文数据库(CJFD)、Medline、Cochrane图书馆与中国生物医学文献数据库(CBMdisc)4个数据库,对1997年1月至2019年6月公开发表的关于中国人阿尔茨海默病LRP-1基因多态性的病例对照研究进行meta分析.结果共纳入16项病例对照研究.综合数据分析,CC基因型及C等位基因与中国人AD发病相关,均P<0.05,差异有统计学意义;中国人携带CC基因型发生AD的风险是携带CT/TT基因型的1.477倍,携带C等位基因发生AD的风险是携带T等位基因的1.669倍.CC基因型及C等位基因与汉族人AD发病亦相关,均P<0.05,差异有统计学意义;汉族人携带CC基因型发生AD的风险是携带CT/TT基因型的1.711倍,携带C等位基因发生AD的风险是携带T等位基因的2.005倍.结论LRP-1基因C766T位点多态性与中国人,尤其是汉族人AD发病风险相关,携带CC基因型和C等位基因的个体有更大风险发生AD.

脂蛋白相关磷脂酶A_2基因沉默对炎症基因表达的影响

目的:观察氧化低密度脂蛋白(oxygenized low density lipoprotein,oxLDL)和脂蛋白相关磷脂酶A2(lip-oprotein associated phospholipase A2,Lp-PLA2)短发夹RNA(shRNA)对小鼠单核巨噬细胞(RAW264.7)Lp-PLA2活性、mRNA表达及炎症基因表达的影响。方法:采用0、20、40、60和80μg/ml oxLDL刺激RAW264.7细胞并用不同剂量Lp-PLA2shRNA转染oxLDL 60μg/ml处理组,应用ELISA、逆转录-聚合酶链反应检测Lp-PLA2、单核细胞趋化蛋白-1(Monocyte Chemoattractant Protein-1,MCP-1)及其mRNA表达的影响。结果:RAW264.7细胞经oxLDL刺激后Lp-PLA2表达明显升高,且呈时间和剂量依赖性。Lp-PLA2shRNA转染小鼠单核巨噬细胞后,炎症基因及mRNA表达明显下降。结论:Lp-PLA2shRNA转染可明显逆转oxLDL刺激引起的RAW264.7细胞炎症基因高表达。

Comparison of three fluorescence labeling and tracking methods of endothelial progenitor cells in laser-injured retina

AIM： To compare three kinds of fluorescent probes for in vitro labeling and in vivo tracking of endothelial progenitor cells（EPCs） in a mouse model of laser-induced retinal injury.METHODS： EPCs were isolated from human umbilical cord blood mononuclear cells and labeled with three different fluorescent probes： 5-（and-6）-carboxyfluorescein diacetate succinimidyl ester（CFSE）, 1,1′-dilinoleyl-3,3,3′,3′-tetramethylindo-carbocyanine perchlorate linked acetylated low-density lipoprotein（Di I-Ac LDL）, and green fluorescent protein（GFP）. The fluorescent intensity of EPCs was examined by confocal microscopy. Survival rate of labeled EPCs was calculated with trypan blue staining, and their adhesive capability was assessed. A mouse model of retinal injury was induced by laser, and EPCs were injected into the vitreous cavity. Frozen section and fluorescein angiography on flat-mounted retinal samples was employed to track the labeled EPCs in vivo.RESULTS： EPCs labeled with CFSE and Di I-Ac LDL exhibited an intense green and red fluorescence at the beginning; the fluorescence intensity decreased gradually to 20.23% and 49.99% respectively, after 28 d. On the contrary, the florescent intensity of GFP-labeled EPCs increased in a time-dependent manner. All labeled EPCs showed normal morphology and no significant change in survival and adhesive capability. In the mouse model, transplantation of EPCs showed a protective effect against retinal injury. EPCs labeled with CFSE and Di I-Ac LDL were successfully tracked in mice during the development of retinal injury and repair; however, GFP-labeled EPCs were not detected in the laser-injured mouse retina.CONCLUSION： The three fluorescent markers used in this study have their own set of advantages and disadvantages. CFSE and Di I-Ac LDL are suitable for short-term EPClabeling, while GFP should be used for long-term labeling. The choice of fluorescent markers should be guided by the purpose of the study.

人C-反应蛋白重组真核表达质粒的构建及其对人脐静脉内皮细胞LOX-1和TF表达的影响

目的构建人C-反应蛋白(C-reactive protein,CRP)重组表达质粒pTracer CMV2-CRP,并观察其在人脐静脉内皮细胞(Human umbilical vein endothelical cells,HUVEC)中的表达及其对凝集素样氧化型低密度脂蛋白受体-1(Lectin-type oxidizedLDL receptor-1,LOX-1)、组织因子(Tissue factor,TF)表达的影响。方法以质粒pCR-BluntⅡ-TOPO-CRP为模板,PCR扩增CRP基因CDS序列,克隆至pTracer CMV2载体中,转化感受态大肠杆菌DH5α,构建重组表达质粒pTracer CMV2-CRP,转染HUVEC,设实验组(转染pTracer CMV2-CRP)、阴性对照组(转染pTracer-CMV2)及正常对照组,各组细胞经G418抗性筛选,RT-PCR及Western b1ot检测CRP基因的过表达效应及CRP的表达对HUVEC中LOX-1和TF转录及蛋白水平的影响。结果重组真核表达质粒pTracer CMV2-CRP经双酶切鉴定及测序证明构建正确。实验组细胞中,CRP基因过表达,且LOX-1和TF基因的转录及蛋白水平明显高于正常对照组和阴性对照组(P<0.05)。结论已成功构建人CRP基因重组真核表达质粒pTracerCMV2-CRP,并在HUVEC中过表达CRP,且明显上调HUVEC中LOX-1和TF的表达,为进一步阐述CRP在动脉粥样硬化形成过程中的作用提供了新的实验依据。