The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane pr...The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins aremembers of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP). The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2 is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones, cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.展开更多
目的:探讨血清固醇调节元件结合蛋白2(sterol regulatory element binding protein-2,SREBP-2)与急性脑梗死的相关性。方法:纳入2020年10月至2021年3月入住的134名急性脑梗死患者和34名健康体检者。通过酶联免疫吸附实验法(enzyme-linke...目的:探讨血清固醇调节元件结合蛋白2(sterol regulatory element binding protein-2,SREBP-2)与急性脑梗死的相关性。方法:纳入2020年10月至2021年3月入住的134名急性脑梗死患者和34名健康体检者。通过酶联免疫吸附实验法(enzyme-linked immunosorbent assay,ELISA)检测血清SERBP-2浓度,并依据急性卒中Org 10172治疗试验(trial of Org 10172 in acute stroke treatment,TOAST)分型和是否合并糖尿病进行亚组分析。使用美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分评估患者的病情严重程度,并分析血清SREBP-2与病情严重程度的相关性。使用改良Rankin量表评估患者的90 d功能预后,并将患者分为预后良好组和预后不良组,比较2组的血清SREBP-2浓度差异,并通过logistic回归分析血清SREBP-2是否与脑梗死预后相关。结果:脑梗死组的血清SREBP-2浓度明显低于对照组[72.60(57.50,83.35)ng/mL vs.86.80(77.20,97.90)ng/mL,P=0.000]。血清SREBP-2浓度识别急性脑梗死患者和健康人群的曲线下面积为0.782(P=0.000)。大动脉粥样硬化型、心源性栓塞型、小动脉闭塞型脑梗死血清SREBP-2浓度均明显低于对照组(P=0.000,P=0.003,P=0.000)。合并糖尿病患者的血清SREBP-2高于不合并糖尿病的患者(P=0.021)。血清SREBP-2浓度与入院NIHSS评分无相关性(P>0.05)。脑梗死患者预后良好组血清SREBP-2浓度较预后不良组低,但差异无统计学意义(P>0.05),logistic回归分析显示血清SREBP-2浓度与脑梗死90 d功能预后无关(OR=1.016,95%CI=0.991~1.042,P=0.205)。结论:血清SREBP-2浓度在急性脑梗死患者中明显下降。血清SREBP-2对识别脑梗死患者与健康人群具有一定的效能。然而,血清SREBP-2浓度与患者病情严重程度和预后无关。展开更多
Background Sterol regulatory element binding protein （SREBP）-2 plays a key role in lipid homeostasis by stimulating gene expression of cholesterol biosynthetic pathways. The insulin-like growth factor binding prote...Background Sterol regulatory element binding protein （SREBP）-2 plays a key role in lipid homeostasis by stimulating gene expression of cholesterol biosynthetic pathways. The insulin-like growth factor binding protein （IGFBP） family regulates growth and metabolism, especially bone cell metabolism, and correlates with osteonecrosis. However, association of their gene polymorphisms with risk of avascular necrosis of the femoral head （ANFH） has rarely been reported. We determined whether SREBP-2 and IGFBP-3 gene polymorphisms were associated with increased ANFH risk in the Chinese population. Methods Two single nucleotide polymorphisms of SREBP2 gene, rs2267439 and rs2267443, and one of IGFBP-3 gene, rs2453839, were selected and genotyped in 49 ANFH patients and 42 control individuals by direct sequencing assay. Results The frequencies of rs2267439 TT and rs2267443 GA of SREBP2 and rs2453839 TT and CT of IGFBP-3 in the ANFH group showed increased and decreased tendencies （against normal control group）, respectively. Interaction analysis of genes revealed that the frequency of carrying rs2267439 TT and rs2267443 GA genotypes of SREBF-2 in ANFH patients was significantly higher than in the control group （P 〈0.05）. Association analysis between polymorphisms and clinical phenotype demonstrated that the disease course in ANFH patients with the rs2453839 TT genotype of IGFBP-3 was significantly shorter than that of CT＋CC carriers （P 〈0.01）. CT＋CC genotype frequency in patients with stage Ill/IV bilateral hip lesions was significantly higher than in those with stage Ill/IV unilateral lesions and stage II/111 bilateral lesions （P 〈0.05-0.02）. Conclusions Our results suggested that interaction of SREBP-2 gene polymorphisms and the relationship between the polymorphisms and clinical phenotype of IGFBP-3 were closely related to increased ANFH risk in the Chinese population. The most significant finding was that the CT＋CC genotype carriers of IGFBP-3 rs2453839 were highly associated with the development of ANFH.展开更多
目的：研究胆固醇调节元件结合蛋白2基因（sterol regulatory element binding protein 2 gene，SREBP2） rs2228314多态性与儿童青少年肥胖和血脂水平的关系。方法：研究对象来自前期工作中收集的两批样本，共2030名7岁至18岁中小学生...目的：研究胆固醇调节元件结合蛋白2基因（sterol regulatory element binding protein 2 gene，SREBP2） rs2228314多态性与儿童青少年肥胖和血脂水平的关系。方法：研究对象来自前期工作中收集的两批样本，共2030名7岁至18岁中小学生，对这些学生进行身体测量和血清总胆固醇（total cholesterol，TC）、三酰甘油（triacylgly-ceride，TG）、高密度脂蛋白胆固醇（low density lipoprotein-cholesterol，HDL-C）、低密度脂蛋白胆固醇（low density lipo-protein-cholesterol ，LDL-C）的检测。采用基质支持的激光释放/电离飞行时间质谱分析检测rs2228314多态性基因型。在显性模型下进行统计学分析，采用t检验比较不同基因型组间血脂水平（计量资料）的差异，采用Logistic回归分析rs2228314多态性与血脂水平的异常（分类资料）和肥胖的关系。结果：rs2228314多态性GC/CC基因型组的HDL-C水平低于GG纯合子，差异有统计学意义（0．10＆#177;0．35 vs．0．14＆#177;0．36，P＝0．020），在显性模型下，调整研究样本、性别和年龄后，rs2228314多态性与 HDL-C 水平的异常相关（ OR ＝1．400，95％ CI：1．027～1．907， P ＝0．033）。调整研究样本、性别、年龄和HDL-C 水平后，rs2228314多态性与肥胖的相关性无统计学意义（OR ＝1．178，95％CI：0．971～1．430， P＝0．096）。结论：携带SREBP2基因rs2228314多态性GC/CC基因型的儿童青少年发生HDL-C水平异常的风险高于GG基因型携带者。展开更多
目的:探讨贞清方对2型糖尿病非酒精性脂肪肝的治疗作用及可能机制.方法:高脂高糖饮食结合小剂量链脲佐菌素(STZ)腹腔注射建立2型糖尿病并发非酒精性脂肪肝大鼠模型.将成模大鼠随机分为模型组、贞清方治疗组和女贞子治疗组(n=8),并设立...目的:探讨贞清方对2型糖尿病非酒精性脂肪肝的治疗作用及可能机制.方法:高脂高糖饮食结合小剂量链脲佐菌素(STZ)腹腔注射建立2型糖尿病并发非酒精性脂肪肝大鼠模型.将成模大鼠随机分为模型组、贞清方治疗组和女贞子治疗组(n=8),并设立正常对照组(n=10),灌胃治疗8wk.比较喂养4、8和16wk时各组大鼠空腹血糖(FBG)、血清甘油三酯(TG)、总胆固醇(TC)、胰岛素(FINs)和胰岛素敏感指数(ISI)的变化.并于喂养16wk时观察各组大鼠肝脏指数、TG含量和血清丙氨酸转氨酶(ALT)的水平以及病理变化.用PCR法观察大鼠肝X受体(LXRα)及其下游固醇调节元件结合蛋白-1c(SREBP-1c) mRNA的表达,免疫组织化学法观察肝脏LXRα蛋白的表达.结果:灌胃干预8wk后,与正常组相比,模型组大鼠FBG、血清TG、肝脏指数及肝脏TG含量明显升高(均P<0.01),胰岛素敏感性明显降低(P<0.01),肝脏脂肪变明显加重,肝脏LXRα mRNA、SREBP-1c mRNA和LXRα蛋白的表达明显增多(均P<0.01).与模型组相比,贞清方治疗组大鼠FBG水平、血清TG水平、肝脏指数及肝脏TG含量明显降低(10.94±3.33mmol/L vs 16.67±4.33mmol/L;0.79±0.27mmol/L vs 1.33±0.33mmol/L;5.72±0.81 vs 7.61±1.24;0.041±0.0110mmol/gvs0.059±0.0160mmol/g,均P<0.01),肝脏脂肪变明显改善,肝脏LXRαmRNA、SREBP-1c mRNA和LXRα蛋白的表达明显减少(0.75±0.11vs1.23±0.17,0.68±0.16 vs 1.07±0.14,0.220±0.071 vs 0.334±0.037,均P<0.01).结论:贞清方对2型糖尿病性非酒精性脂肪肝具有一定的治疗作用,且其治疗作用可能与贞清方能下调非酒精性脂肪肝组织LXRα的表达有关.展开更多
文摘The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins aremembers of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP). The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2 is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones, cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.
文摘目的:探讨血清固醇调节元件结合蛋白2(sterol regulatory element binding protein-2,SREBP-2)与急性脑梗死的相关性。方法:纳入2020年10月至2021年3月入住的134名急性脑梗死患者和34名健康体检者。通过酶联免疫吸附实验法(enzyme-linked immunosorbent assay,ELISA)检测血清SERBP-2浓度,并依据急性卒中Org 10172治疗试验(trial of Org 10172 in acute stroke treatment,TOAST)分型和是否合并糖尿病进行亚组分析。使用美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分评估患者的病情严重程度,并分析血清SREBP-2与病情严重程度的相关性。使用改良Rankin量表评估患者的90 d功能预后,并将患者分为预后良好组和预后不良组,比较2组的血清SREBP-2浓度差异,并通过logistic回归分析血清SREBP-2是否与脑梗死预后相关。结果:脑梗死组的血清SREBP-2浓度明显低于对照组[72.60(57.50,83.35)ng/mL vs.86.80(77.20,97.90)ng/mL,P=0.000]。血清SREBP-2浓度识别急性脑梗死患者和健康人群的曲线下面积为0.782(P=0.000)。大动脉粥样硬化型、心源性栓塞型、小动脉闭塞型脑梗死血清SREBP-2浓度均明显低于对照组(P=0.000,P=0.003,P=0.000)。合并糖尿病患者的血清SREBP-2高于不合并糖尿病的患者(P=0.021)。血清SREBP-2浓度与入院NIHSS评分无相关性(P>0.05)。脑梗死患者预后良好组血清SREBP-2浓度较预后不良组低,但差异无统计学意义(P>0.05),logistic回归分析显示血清SREBP-2浓度与脑梗死90 d功能预后无关(OR=1.016,95%CI=0.991~1.042,P=0.205)。结论:血清SREBP-2浓度在急性脑梗死患者中明显下降。血清SREBP-2对识别脑梗死患者与健康人群具有一定的效能。然而,血清SREBP-2浓度与患者病情严重程度和预后无关。
文摘Background Sterol regulatory element binding protein （SREBP）-2 plays a key role in lipid homeostasis by stimulating gene expression of cholesterol biosynthetic pathways. The insulin-like growth factor binding protein （IGFBP） family regulates growth and metabolism, especially bone cell metabolism, and correlates with osteonecrosis. However, association of their gene polymorphisms with risk of avascular necrosis of the femoral head （ANFH） has rarely been reported. We determined whether SREBP-2 and IGFBP-3 gene polymorphisms were associated with increased ANFH risk in the Chinese population. Methods Two single nucleotide polymorphisms of SREBP2 gene, rs2267439 and rs2267443, and one of IGFBP-3 gene, rs2453839, were selected and genotyped in 49 ANFH patients and 42 control individuals by direct sequencing assay. Results The frequencies of rs2267439 TT and rs2267443 GA of SREBP2 and rs2453839 TT and CT of IGFBP-3 in the ANFH group showed increased and decreased tendencies （against normal control group）, respectively. Interaction analysis of genes revealed that the frequency of carrying rs2267439 TT and rs2267443 GA genotypes of SREBF-2 in ANFH patients was significantly higher than in the control group （P 〈0.05）. Association analysis between polymorphisms and clinical phenotype demonstrated that the disease course in ANFH patients with the rs2453839 TT genotype of IGFBP-3 was significantly shorter than that of CT＋CC carriers （P 〈0.01）. CT＋CC genotype frequency in patients with stage Ill/IV bilateral hip lesions was significantly higher than in those with stage Ill/IV unilateral lesions and stage II/111 bilateral lesions （P 〈0.05-0.02）. Conclusions Our results suggested that interaction of SREBP-2 gene polymorphisms and the relationship between the polymorphisms and clinical phenotype of IGFBP-3 were closely related to increased ANFH risk in the Chinese population. The most significant finding was that the CT＋CC genotype carriers of IGFBP-3 rs2453839 were highly associated with the development of ANFH.
文摘目的：研究胆固醇调节元件结合蛋白2基因（sterol regulatory element binding protein 2 gene，SREBP2） rs2228314多态性与儿童青少年肥胖和血脂水平的关系。方法：研究对象来自前期工作中收集的两批样本，共2030名7岁至18岁中小学生，对这些学生进行身体测量和血清总胆固醇（total cholesterol，TC）、三酰甘油（triacylgly-ceride，TG）、高密度脂蛋白胆固醇（low density lipoprotein-cholesterol，HDL-C）、低密度脂蛋白胆固醇（low density lipo-protein-cholesterol ，LDL-C）的检测。采用基质支持的激光释放/电离飞行时间质谱分析检测rs2228314多态性基因型。在显性模型下进行统计学分析，采用t检验比较不同基因型组间血脂水平（计量资料）的差异，采用Logistic回归分析rs2228314多态性与血脂水平的异常（分类资料）和肥胖的关系。结果：rs2228314多态性GC/CC基因型组的HDL-C水平低于GG纯合子，差异有统计学意义（0．10＆#177;0．35 vs．0．14＆#177;0．36，P＝0．020），在显性模型下，调整研究样本、性别和年龄后，rs2228314多态性与 HDL-C 水平的异常相关（ OR ＝1．400，95％ CI：1．027～1．907， P ＝0．033）。调整研究样本、性别、年龄和HDL-C 水平后，rs2228314多态性与肥胖的相关性无统计学意义（OR ＝1．178，95％CI：0．971～1．430， P＝0．096）。结论：携带SREBP2基因rs2228314多态性GC/CC基因型的儿童青少年发生HDL-C水平异常的风险高于GG基因型携带者。
文摘目的:探讨贞清方对2型糖尿病非酒精性脂肪肝的治疗作用及可能机制.方法:高脂高糖饮食结合小剂量链脲佐菌素(STZ)腹腔注射建立2型糖尿病并发非酒精性脂肪肝大鼠模型.将成模大鼠随机分为模型组、贞清方治疗组和女贞子治疗组(n=8),并设立正常对照组(n=10),灌胃治疗8wk.比较喂养4、8和16wk时各组大鼠空腹血糖(FBG)、血清甘油三酯(TG)、总胆固醇(TC)、胰岛素(FINs)和胰岛素敏感指数(ISI)的变化.并于喂养16wk时观察各组大鼠肝脏指数、TG含量和血清丙氨酸转氨酶(ALT)的水平以及病理变化.用PCR法观察大鼠肝X受体(LXRα)及其下游固醇调节元件结合蛋白-1c(SREBP-1c) mRNA的表达,免疫组织化学法观察肝脏LXRα蛋白的表达.结果:灌胃干预8wk后,与正常组相比,模型组大鼠FBG、血清TG、肝脏指数及肝脏TG含量明显升高(均P<0.01),胰岛素敏感性明显降低(P<0.01),肝脏脂肪变明显加重,肝脏LXRα mRNA、SREBP-1c mRNA和LXRα蛋白的表达明显增多(均P<0.01).与模型组相比,贞清方治疗组大鼠FBG水平、血清TG水平、肝脏指数及肝脏TG含量明显降低(10.94±3.33mmol/L vs 16.67±4.33mmol/L;0.79±0.27mmol/L vs 1.33±0.33mmol/L;5.72±0.81 vs 7.61±1.24;0.041±0.0110mmol/gvs0.059±0.0160mmol/g,均P<0.01),肝脏脂肪变明显改善,肝脏LXRαmRNA、SREBP-1c mRNA和LXRα蛋白的表达明显减少(0.75±0.11vs1.23±0.17,0.68±0.16 vs 1.07±0.14,0.220±0.071 vs 0.334±0.037,均P<0.01).结论:贞清方对2型糖尿病性非酒精性脂肪肝具有一定的治疗作用,且其治疗作用可能与贞清方能下调非酒精性脂肪肝组织LXRα的表达有关.
