Overexpression of low-density lipoprotein receptor prevents neurotoxic polarization of astrocytes via inhibiting NLRP3 inflammasome activation in experimental ischemic stroke

Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.

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.

Oxidized low-density lipoprotein receptor 1:a novel potential therapeutic target for intracerebral hemorrhage

Oxidized low-density lipoprotein receptor 1(OLR1)is upregulated in neurons and participates in hypertension-induced neuronal apoptosis.OLR1 deletion exerts protective effects on cerebral damage induced by hypertensive-induced stroke.Therefore,OLR1 is likely involved in the progress of intracerebral hemorrhage.In this study,we examined the potential role of OLR1 in intracerebral hemorrhage using a rat model.OLR1 small interfering RNA(10μL;50 pmol/μL)was injected into the right basal ganglia to knock down OLR1.Twenty-four hours later,0.5 U collagenase type VII was injected to induce intracerebral hemorrhage.We found that knockdown of OLR1 attenuated neurological behavior impairment in rats with intracerebral hemorrhage and reduced hematoma,neuron loss,inflammatory reaction,and oxidative stress in rat brain tissue.We also found that silencing of OLR1 suppressed ferroptosis induced by intracerebral hemorrhage and the p38 signaling pathway.Therefore,silencing OLR1 exhibits protective effects against secondary injury of intracerebral hemorrhage.These findings suggest that OLR1 may be a novel potential therapeutic target for intracerebral hemorrhage.

Effect of Curcumin on the Gene Expression of Low Density Lipoprotein Receptors

Objective： To investigate the molecular mechanisms and effective target ponits of lipid-lowering drug, Rhizoma Curcumae Longae, and study the effect of curcumin on the expression of low density lipoprotein （LDL） receptors in macrophages in mice. Methods. Macrophages in mice were treated with curcumin, which was purified from the ethanolly extraction of Rhizoma Curcumae Longae for 24 h. The LDL receptors expressed in the macrophages were determined by enzyme-linked immunosorbent assay （ELISA） and assay of Dil labeled LDL uptake by flow cytometer. Results： It was found for the first time that 10 μmol/L-50 μmol/L curcumin could obviously up-regulate the expression of LDL receptor in macrophages in mice, and a dose-effect relationship was demonstrated. Conclusion： One of the lipid-lowering mechanisms of traditional Chinese medicine, Rhizoma Curcumae Longae, was completed by the effect of curcumin through the up-regulation of the expression of LDL receptor.

Relationship between the low density lipoprotein receptor gene polymorphism and serum lipid levels in the Guangxi Bai Ku Yao population

Objectives Bai Ku Yao(White-trousers Yaos)is a special branch of Yao minority in China.They are now living in both Lihu and Baxu villages,Nandan County, Guangxi,China.The population size is about 30,000.The special customs and culture of Bai Ku Yao,including their special clothing,intra-ethnic marriages and alcohol intake are still completely conserved to the present day.In previous epidemiologic studies,we found that the serum lipid levels and the prevalence of hyperlipidaemia were lower in Bai Ku Yao than in Han Chinese from the same region.This ethnic difference in serum lipid profiles is still not well known.We hypothesized that there may be significant differences in some genetic polymorphismsssociation of low density lipoprotein receptor (LDL-R) genepolymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations.Methods A total of 1024 subjects of Bai Ku Yao and 792 participants of Han Chinese were stud- ied by a stratified randomized cluster sampling.Epidemiological survey was carried out using internationally standardized methods.Information on demographics,socioeconomic status, and lifestyle factors was collected with standardized questionnaires. The height,weight,waist circumference,blood pressure, and serum total cholesterol(TC),triglyceride(TG), high-density lipoprotein cholesterol(HDL-C),low-density lipoprotein cholesterol(LDL-C),apolipoprotein(Apo) A1, and ApoB were measured.Body massindex(BMI,kg/m2) was calculated.Genotyping of the LDL-RAvaⅡwas performed by polymerse chain reaction and restriction fragment length polymorphism combined with gel electrophoresis,and then confirmed by direct sequencing.Results(l)The height,weight,serum TC,HDL-C,LDL-C,ApoAl levels and the ratio of ApoAl to ApoB were lower in Bai Ku Yao than in Han Chinese(P【0.01 for all),whereas the percentage of subjects who consumed alcohol or smoked cigarettes was higher in Bai Ku Yao than in Han Chinese(P【0.01 for each).(2) The frequency of A+ allele in Bai Ku Yao was 34.5%,and the frequencies of A-A-,A-A+ and A+A + genotypes were 42.6%,45.9%and 11.5%;respectively. The frequency of A+ allele in Han Chinese was 19.3%(P【0.001),and the frequencies of A-A-,A-A + and A+A+ genotypes were 64.9%,31.6%and 3.5%(P【0.001);respectively. The frequencies of A-A-,A-A+ and A+A+ genotypes in Bai Ku Yao were significant difference between males and females,between normal TC and high TC subgroup, and between normal LDL-C and high LDL-C subgroup (P【0.05 for all),whereas the frequencies of A- and A+ ? alleles in Han Chinese were significant difference between males and females(P【0.05).(3) Serum LDL-C levels in Bai Ku Yao were significant difference among the A-A-, A-A+ and A+A+ genotypes(P【0.05),the A+ carriers had higher serum LDL-C levels.Serum HDL-C levels in Han Chiese were significant difference among the A-A-,A-A + and A+A+ genotypes(P【0.01),the A+ carriers had higher serum HDL-C levels.(4) After adjusting other factors,the prevalence of LDL-C abnormality was still higher in Han Chiese than in Bai Ku Yao.The prevalence of TC abnormality in Han Chinese was almost twice high as in Bai Ku Yao. The age and diet were common risk factor for TC abnormality. No effect of AvaⅡgenotype or alcohol consumption on the TC abnormality was found,but the combination of geno-type and alcohol consumption can increase the prevalence of TC abnormality[Exp(B) =(1.154)].Age was negatively cor- related with TG level.Conclusions Serum TC and LDL-C levels were lower in Bai Ku Yao than in Han Chinese.There were significant differences in the AvaⅡallele and genotype frequencies between the he A+ carriers in Bai Ku Yao had higher serum LDL-C levels,whereas the A+ carriers in Han had higher serum HDL-C levels.Interactions between alcohol consumption or cigarette smoking and the LDL-R AvaⅡgenotype were also observed.The differences in the serum lipid profiles between the two ethnic groups might partly result from different genotypic frequency of LDL-R AvaⅡpolymorphism or differentgene-enviromental interactions.Bai Ku Yao and Han population,the frequency of A + allele was higher in Bai Ku Yao than in Han.T between the two ethnic groups.Therefore,the aim of the present study was to detect the

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.

绝经后2型糖尿病LRP5基因多态性与骨量异常的研究

目的分析低密度脂蛋白受体相关蛋白5(low density lipoprotein receptor related protein 5,LRP5)rs556442、rs312778位点基因多态性及突变在绝经后女性2型糖尿病(type 2 diabetes mellitus,T2DM)患者中骨量异常的意义。方法收集2021年5月至2023年5月新疆石河子地区的142例绝经后女性资料进行回顾性分析,分为正常对照组(A组,n=29)、T2DM组(B组,n=30)、骨量降低组(C组,n=28)、骨量降低+T2DM组(D组,n=55)。收集记录相关基线资料,运用全自动生化测定仪测定受试者血糖、血脂及骨代谢指标。通过双能X线骨密度仪测定骨密度(bone mineral density BMD),LRP5基因位点多态性采用飞行时间质谱法(MALDI-TOF-MS)测定,采用SNPscan技术对上述SNP位点进行基因分型。结果①四组基线资料比较,绝经年限、年龄及腰臀比(waist hip ratio,WHR)比较差异具有统计学意义(P<0.05);②与A组相比,B组的空腹血糖(FPG)、糖化血红蛋白(HbA1c)升高(P<0.05);D组的FPG、HbA1c的血清学水平升高,甘油三酯(TG)血清学水平降低(P<0.05);③rs556442位点:与A组相比,D组基因型分布(AA/AG/GG基因型)有统计学意义(P<0.05);rs312778位点组间基因型(CC/CT/TT基因型)及等位基因分布频率均无统计学意义(P>0.05);④rs556442位点:与AA基因型相比,B、C组AG/GG基因型的股骨颈BMD水平降低;D组AG/GG型的HDL血清学水平降低(P<0.05)。rs312778位点:与CC基因型相比,A组HbA1C、FPG血清学水平较CT/TT基因型低(P<0.05);D组CT/TT基因型的低密度脂蛋白(LDL)血清学水平升高(P<0.05);⑤多元线性回归分析:rs556442位点,TG增加是腰L_(1~4)BMD降低的危险因素(P<0.05);rs312778位点,体质量指数(body mass index,BMI)降低是腰L_(1~4)及股骨颈BMD降低的危险因素,TG增加是腰L_(1~4)BMD降低的危险因素(P<0.05);⑥在rs556442、rs312778位点骨量异常与基因型分布均无统计学意义(P>0.05)。结论新疆石河子地区绝经后T2DM女性患者LRP5基因rs556442、rs312778基因位点的突变可能与骨量降低有关。

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.

Lectin-like oxidized low-density lipoprotein receptor-1:protein,ligands,expression and pathophvsiological significance

Objective To review the recent research progress in lectin-like oxidized low-density lipoprotein receptor-1 （LOX-1） including its protein, ligands, expression and pathophysiological significance. Data sources Information included in this article was identified by searching of PUBMED （1997-2006） online resources using the key term LOX-1. Study selection Mainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected. Results The key issues related to the LOX-1 protein as well as ligands for LOX-1. Factors regulating the expression of LOX-1 were summarized. The pathophysiological functions of LOX-1 in several diseases were discussed. Conclusions Identification of LOX-1 and a definition of its biological role in pathophysiologic states provide deeper insight into the pathogenesis of some cardiovascular diseases especially in atherosclerosis and provide a potential selective therapeutic approach. LOX-1 is unlocking and drugs targeting LOX-1 might be a promising direction to explore.

Mechanisms of dysregulation of low-density lipoprotein receptor expression in HepG2 cells induced by inflammatory cytokines

Background Low-density lipoprotein （LDL） receptor is normally regulated via a feedback system that is dependent on intracellular cholesterol levels. We have demonstrated that cytokines disrupt cholesterol-mediated LDL receptor feedback regulation causing intracellular accumulation of unmodified LDL in peripheral cells. Liver is the central organ for lipid homeostasis. The aim of this study was to investigate the regulation of cholesterol exogenous uptake via LDL receptor and its underlying mechanisms in human hepatic cell line （HepG2） cells under physiological and inflammatory conditions. Methods Intracellular total cholesterol （TC）, free cholesterol （FC） and cholesterol ester （CE） were measured by an enzymic assay. Oil Red O staining was used to visualize lipid droplet accumulation in cells. Total cellular RNA was isolated from cells for detecting LDL receptor, sterol regulatory element binding protein （SREBP）-2 and SREBP cleavage-activating protein （SCAP） mRNA levels using real-time quantitative PCR. LDL receptor and SREBP-2 protein expression were examined by Western blotting. Confocal microscopy was used to investigate the translocation of SCAP-SREBP complex from the endoplasmic reticulum （ER） to the Golgi by dual staining with anti-human SCAP and anti-Golgin antibodies. Results LDL loading increased intracellular cholesterol level, thereby reduced LDL receptor mRNA and protein expression in HepG2 cells under physiological conditions. However, interleukin 1β （IL-1β） further increased intracellular cholesterol level in the presence of LDL by increasing both LDL receptor mRNA and protein expression in HepG2. LDL also reduced the SREBP and SCAP mRNA level under physiological conditions. Exposure to IL-1β caused over-expression of SREBP-2 and also disrupted normal distribution of SCAP-SREBP complex in HepG2 by enhancing translocation of SCAP-SREBP from the ER to the Golgi despite a high concentration of LDL in the culture medium. Conclusions IL-1β disrupts cholesterol-mediated LDL receptor feedback regulation by enhancing SCAP-SREBP complex translocation from the ER to the Golgi, thereby increasing SREBP-2 mediated LDL receptor expression even in the presence of high concentration of LDL. This results in LDL cholesterol accumulation in hepatic cells via LDL receptor pathway under inflammatory stress.

Genetically confirmed familial hypercholesterolemia in outpatients with hypercholesterolemia

Background Familial hypercholesterolemia （FH） is an autosomal dominant disorder of lipoprotein metabolism which can lead to premature coronary heart disease （pCHD）. There are about 3.8 million potential FH patients in China, whereas the clinical and genetic data of FH are limited. Methods Dutch Lipid Clinic Network （DLCN） criteria was used to diagnose FH in outpatients with hypercholesterolemia. Resequencing chip analysis combined with Sanger sequencing validation were used to identify mutations in the definite FH patients according to DLCN criteria. In silico analysis was conducted in mutations with previously unknown pathogenicity. Then, the novel mutant receptors were transfected into human embryo kidney 293 （HEK-293） cells. The binding and the internalization activities of the mu- tant receptors were analyzed by flow cytometry. Results The prevalence of definite FH in outpatients with hypercholesterolemia in this study is 3.2%. Using genetic testing, one homozygous FH （HoFH）, one heterozygous FH （HeFH） and three compound heterozygous FH patients were confirmed. Eight mutations in low-density lipoprotein receptor （LDLR） gene were identified, in which c.357delG was a novel mutation and co-segregated with the FH phenotype. Bioinformatic analysis confirmed that c.357delG was a pathogenic mutation. Furthermore, when compared with the wild-type LDLRs by flow eytometry analysis, the binding and internalization activities of c.357delG mutant LDLRs were reduced by 35% and 49%, respectively. Conclusions This study identified eight LDLR gene mutations in five patients with definite FH, in which c.357delG is a novel pathogenic mutation. These findings increase our understanding of the genetic spectrum of FH in China.

Linkage of the cholesterol 7α-hydroxylase gene and low-density lipoprotein cholesterol conditional on apolipoprotein E association: the National Heart, Lung, and Blood Institute Family Heart Study

Background Genetic factors account for approximately 50% of the individual variation in plasma low-density lipoprotein cholesterol (LDL-C) concentrations in the general population. Several candidate genes have been proposed but their relative contributions to the variance in LDL-C are not known, except for apolipoprotein E (apoE). We report here an investigation of the relationship between LDL-C and cholesterol 7α-hydroxylase (CYP7), as well as apoE and low-density lipoprotein receptor (LDLR), three pivotal genes in LDL metabolism. Methods Our study population included more than 200 nuclear families with increased coronary heart disease (CHD) risk from the National Heart, Lung, and Blood Institute (NHLBI) Family Heart Study. Variance-component linkage methods, a measured genotype approach, and a variance-component linkage analysis conditional on a measured genotype association were used. Results The results showed significant linkage between a genetic determinant of plasma LDL-C concentrations and a polymorphism near CYP7 with its allelic variation accounting for 27% of the total LDL-C variation. There is significant association between plasma LDL-C concentrations and apoE genotypes. Conditional on the apoE association, the total LDL-C variation accounted by allelic variation of a polymorphism near CYP7 was increased significantly.Conclusion Our results suggest the apoE and CYP7 may be two important genes accounting for the genetic variation of plasma LDL-C concentrations in a population with cardiovascular diseases.

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.

Natural anti-oxLDL IgM monoclonal antibody in the pathogenesis of atherosclerosis

Objective To explore the role and the possible molecular mechanisms of natural anti-oxLDL IgM monoclonal antibody played and involved in pathogenesis of atherosclerosis. Methods Natural anti-oxLDL IgM monoclonal antibody 3A6 was generated by using standard hybridoma production techniques. Influence of 3A6 on formation of foam cells was observed by Oil Red O staining and affinity of Na125I-conjugated oxLDL on the naive and LPS-activated macrophages. After LPS stimulation on macrophages, anti-TLR4 neutralizing mAb, p38MAPK specific inhibitor SB203580, NF-kB specific inhibitor PDTC or RNAi targeting Fcα/μ receptor (Fcamr) were applied, respectively. Results Natural anti-oxLDL IgM monoclonal antibody 3 A6 were found specifically inhibit the binding of CuoxLDL to naive macrophages but not the binding of CuoxLDL to LPS-activated macrophages. It also promoted the formation of CuoxLDL-mediated foam macrophages. 3A6 F(ab')2 or pre-incubation with un-related IgM inhibited the binding of 3A6/CuoxLDL complex to LPS-activated macrophages. LPS up-regulated the expression of Fcamr in macrophages in a dose- and time-dependent manner, which was attenuated by treatment with anti-TLR4. LPS induced the phosphorylation of p38MAPK and translocation of NF-kB p65, contributing to the up-regulated expression of Fcα/μ receptor in macrophages. Conclusions Natural anti-oxLDL IgM monoclonal antibody 3A6 specifically inhibited the binding of CuoxLDL to naive macrophages in vitro. However, LPS, through the Toll-like receptor (TLR)4 receptor, activated the p38MAPK and NF-kB pathways and up-regulated the expression of Fcα/μ receptor in macrophages, which promoted the binding of 3A6/CuoxLDL complex to macrophages through binding with Fc fragments and the formation of foam macrophages. Therefore, our findings provide a new explanation why bacterial infection deteriorates the pathogenesis of atherosclerosis.

Familial Hypercholesterolemia with Two Mutations in LDLR Gene: A Case Report and Literature Review

We report a case of Familial hypercholesterolemia (FH) with two mutations in low density lipoprotein receptor (LDLR) gene and speculate the correlation between the newly discovered mutation type of LDLR gene and FH. We collected and analyzed the clinical data of the proband in the case and her immediate family members, and detected the LDLR, Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK-9) and Apolipoprotein B (Apo B) gene in the peripheral blood of all the participants. We found that the curative effect of the patient is limited, but no obvious complication was detected. Genetic testing results pointed out that there were two mutations in the patient’s LDLR gene. One was p.W483* mutation in exon 10 (c. 1448 G > A), another was p.T534I mutation in exon 11 (c. 1601 C > T). The p. W483* mutation in exon 10 was detected in the father and sister, additionally p. T534I mutation in exon 11 was detected in the mother. Both the two LDLR gene mutations are inherited from her parents. We hypothesize that the patient in this case was a complex heterozygote. The newly discovered mutation gene (T534I) may be one of the important causes of dyslipidemia in patients, and its adverse effects are more serious than W483* which have been reported. Also, we predict that the T534I mutation will not cause serious early onset of cardiovascular complications.

The interplay between non-esterified fatty acids and bovine peroxisome proliferator-activated receptors: results of an in vitro hybrid approach

Background: In dairy cows circulating non-esterified fatty acids(NEFA) increase early post-partum while liver and other tissues undergo adaptation to greater lipid metabolism, mainly regulated by peroxisome proliferator-activated receptors(PPAR). PPAR are activated by fatty acids(FA), but it remains to be demonstrated that circulating NEFA or dietary FA activate bovine PPAR. We hypothesized that circulating NEFA and dietary FA activate PPAR in dairy cows.Methods: The dose-response activation of PPAR by NEFA or dietary FA was assessed using HP300 e digital dispenser and luciferase reporter in several bovine cell types. Cells were treated with blood plasma isolated from Jersey cows before and after parturition, NEFA isolated from the blood plasma, FA released from lipoproteins using milk lipoprotein lipase(LPL), and palmitic acid(C16:0). Effect on each PPAR isotype was assessed using specific synthetic inhibitors.Results: NEFA isolated from blood serum activate PPAR linearly up to ~ 4-fold at 400 μmol/L in MAC-T cells but had cytotoxic effect. Addition of albumin to the culture media decreases cytotoxic effects of NEFA but also PPAR activation by ~ 2-fold. Treating cells with serum from peripartum cows reveals that much of the PPAR activation can be explained by the amount of NEFA in the serum(R~2 = 0.91) and that the response to serum NEFA follows a quadratic tendency, with peak activation around 1.4 mmol/L. Analysis of PPAR activation by serum in MAC-T, BFH-12 and BPAEC cells revealed that most of the activation is explained by the activity of PPARδ and PPARγ, but not PPARα. Palmitic acid activated PPAR when added in culture media or blood serum but the activation was limited to PPARδ and PPARα and the response was nil in serum from post-partum cows. The addition of LPL to the serum increased > 1.5-fold PPAR activation.Conclusion: Our results support dose-dependent activation of PPAR by circulating NEFA in bovine, specifically δand γ isotypes. Data also support the possibility of increasing PPAR activation by dietary FA;however, this nutrigenomics approach maybe only effective in pre-partum but not post-partum cows.

Therapeutic approach targeting apolipoprotein E binding region and low-density lipoprotein receptor for Alzheimer's disease

Approximately 13% of the population over the age of 65 years is estimated to have AD. The total number of cases is expected to increase over the coming decades. The apolipoprotein E (ApoE) genotype is the greatest genetic deter-minant for Alzheimer's disease (AD) development. The ApoE4 allele increases the risk of AD by 4 to 14 fold while the ApoE2 allele has an opposing effect;decreasing risk. Indeed many studies have demonstrated that carriers of the ApoE2 allele are associated with greater likelihood of survival to advanced age, superior verbal learning ability in advanced age, and reduced accumulation of amyloid pathology in the aged brain. In addition, it is known that ApoE proteins have different affinities for the low-density lipoprotein receptor (LDLR), with ApoE2 having the weakest binding to the LDL receptor at < 2% relative to ApoE3 and E4. Because ApoE2 has shown protective effects in re-gard to AD, a novel approach for ApoE4 carriers may be to create a peptide antagonist that blocks the ApoE inter-actions with LDLR at its 135-150 N-terminal binding domain. This peptide may create a more ApoE2-like structure by decreasing the affinity of ApoE4 for LDLR thereby reducing AD onset, memory impairment, and amyloid plaque formation. In this review, we will discuss the different detrimental effects that ApoE4 can cause. Most importantly, we will review how ApoE4 binding to LDLR promotes AD pathogenesis and how blocking ApoE4 binding may be a promising novel therapeutic approach for AD.

家族性高胆固醇血症的诊断及治疗研究进展

家族性高胆固醇血症(FH)是脂蛋白代谢异常所导致的遗传性疾病,通常为常染色体显性遗传,由于长期暴露于高水平低密度脂蛋白下,FH患者发生冠状动脉疾病的风险显著升高。基因检测对FH的诊断至关重要,除此之外,低密度脂蛋白受体功能检测对FH的治疗也具有重要意义。本文将从FH的诊断筛查、治疗方案及低密度脂蛋白受体功能检测等方面进行综述。

低密度脂蛋白受体基因AvaⅡ和NcoⅠ位点多态性与缺血性脑卒中的相关性研究

目的探讨低密度脂蛋白受体(LDLR)基因AvaⅡ、NcoⅠ位点多态性与缺血性脑卒中(IS)发生的相关性,并分析AvaⅡ、NcoⅠ位点不同基因型血脂水平的变化。方法选取2019年6—11月就诊于泉州市第一医院的140例IS患者作为IS组,另选取同期于本院体检的130名健康体检者作为对照组,两组均进行LDLR基因AvaⅡ、NcoⅠ位点多态性及三酰甘油(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDLC)、低密度脂蛋白胆固醇(LDL-C)、载脂蛋白A1(ApoA1)、载脂蛋白B(ApoB)水平检测。比较两组临床资料和LDLR基因AvaⅡ、NcoⅠ位点基因型分布和等位基因频率及不同基因型各血脂水平。结果IS组吸烟、高血压史、糖尿病史占比及收缩压、舒张压、TG、水平均高于对照组,HDL-C、ApoA1水平低于对照组,差异有统计学意义(P<0.05);两组年龄、性别、饮酒史占比、TC、LDL-C、ApoB水平比较差异无统计学意义。两组AvaⅡ位点基因型分布和等位基因频率比较差异有统计学意义(P<0.05),NcoⅠ位点基因型分布和等位基因频率比较差异均无统计学意义。两组组内AvaⅡ、NcoⅠ位点不同基因型TC、HDL-C、LDL-C、ApoA1、ApoB水平及AvaⅡ位点不同基因型TG水平和IS组NcoⅠ位点不同基因型TG水平比较差异均无统计学意义,对照组组内NcoⅠ位点不同基因型TG水平比较差异有统计学意义(P<0.05)。AvaⅡ位点:IS组TT、TC基因型TG水平均高于对照组,HDL-C、ApoA1水平均低于对照组,CC基因型ApoA1水平低于对照组,差异均有统计学意义(P<0.05);两组CC基因型TG、HDL-C水平及同一基因型间TC、LDL-C、ApoB水平比较差异均无统计学意义。NcoⅠ位点:IS组AA基因型TG水平高于对照组,AA、AG基因型HDL-C、ApoA1水平均低于对照组,差异有统计学意义(P<0.05);两组AG、GG基因型TG水平和GG基因型HDL-C、ApoA1水平及同一基因型间TC、LDL-C、ApoB水平比较差异均无统计学意义。结论LDLR基因AvaⅡ位点多态性与IS相关,而NcoⅠ位点多态性与IS无关。泉州地区IS患者AvaⅡ、NcoⅠ位点的多态性与TG、TC、HDL-C、LDL-C、ApoA1、ApoB等血脂水平无关。

LRP6基因突变导致选择性先天缺牙的研究进展

选择性先天缺牙是由遗传或环境因素导致的牙齿数目异常,多累及恒牙列。低密度脂蛋白受体相关蛋白6(low-density lipoprotein receptor-related protein 6,LRP6)是选择性先天缺牙的常见致病基因之一,该基因突变为常染色体显性遗传,可导致非综合征型先天缺牙或综合征型先天缺牙;非综合征型先天缺牙仅表现为牙齿数目、形态异常;综合征型先天缺牙可表现为耳部发育畸形、口面裂、毛发稀少、汗腺异常等。笔者就近年来关于LRP6基因突变导致选择性先天缺牙的表型及基因突变特点的研究现况进行综述,文献收纳24个LRP6基因突变位点和38例相关先天缺牙患者,发现LRP6基因突变导致的选择性先天缺牙好发于上颌侧切牙及上下颌第二前磨牙和第一前磨牙,极少发生于第一磨牙,尤其是下颌第一磨牙,未见上颌中切牙缺失。LRP6基因在牙发育过程中主要通过WNT/β-catenin信号通路发挥重要作用,LRP6基因突变可导致蛋白表达和功能异常、信号通路破坏从而导致选择性先天缺牙。现有文献结果显示,LRP6基因突变好发于胞外段E1、E2亚结构域,影响WNT/β-catenin信号通路的传导而致病。然而目前对于选择性先天缺牙仍缺乏成熟完善的对因治疗。