Secreted Frizzled-Related Protein 5 Mediates Wnt5a Expression in Microcystin-Leucine-Arginine-Induced Liver Lipid Metabolism Disorder in Mice

Objective Microcystin-leucine-arginine(MC-LR)exposure induces lipid metabolism disorders in the liver.Secreted frizzled-related protein 5(SFRP5)is a natural antagonist of winglesstype MMTV integration site family,member 5A(Wnt5a)and an anti-inflammatory adipocytokine.In this study,we aimed to investigate whether MC-LR can induce lipid metabolism disorders in hepatocytes and whether SFRP5,which has anti-inflammatory effects,can alleviate the effects of hepatic lipid metabolism by inhibiting the Wnt5a/Jun N-terminal kinase(JNK)pathway.Methods We exposed mice to MC-LR in vivo to induce liver lipid metabolism disorders.Subsequently,mouse hepatocytes that overexpressed SFRP5 or did not express SFRP5 were exposed to MC-LR,and the effects of SFRP5 overexpression on inflammation and Wnt5a/JNK activation by MC-LR were observed.Results MC-LR exposure induced liver lipid metabolism disorders in mice and significantly decreased SFRP5 mRNA and protein levels in a concentration-dependent manner.SFRP5 overexpression in AML12cells suppressed MC-LR-induced inflammation.Overexpression of SFRP5 also inhibited Wnt5a and phosphorylation of JNK.Conclusion MC-LR can induce lipid metabolism disorders in mice,and SFRP5 can attenuate lipid metabolism disorders in the mouse liver by inhibiting Wnt5a/JNK signaling.

Secreted Frizzled-Related Protein 5 (SFRP5) in Patients with Obstructive Sleep Apnea

Objective Obstructive sleep apnea (OSA) is closely related to obesity, insulin resistance and inflammation. Secreted frizzled-related protein 5 (SFRP5) is a recently discovered adipokine. It is involved in insulin resistance and inflammation in obesity. This study aimed at evaluating the association between SFRP5and sleeping characteristics as well as biochemical parameters of OSA patients.Methods This was a prospective case control study. Nondiabetic OSA patients and controls were consecutively recruited and divided into three groups: OSA group, apnea–hypopnea Index (AHI)≥5/h; healthy controls with normal body mass index (BMI); obese controls without OSA, and BMI > 24.0 kg/m2. All participants underwent polysomnography (PSG). Plasma SFRP5 was examined using enzyme-linked immunosorbent assay (ELISA). Blood biochemical examinations, including fasting blood glucose (FBG), lipid profile, hypersensitive Creactive protein (hsCRP), were performed early in the morning after PSG. Patients with severe OSA were treated with nasal continuous positive airway pressure (nCPAP), and plasma SFRP5 was repeatedly measured for comparison.Results Sixty-eight subjects were enrolled in the study, including 38 patients of OSA, whose medium AHI was 58.70 /h (36.63, 71.15), 20 obese controls, and 10 healthy controls. The plasma SFRP5 level of OSA patients was not significantly different from that of healthy controls or obese controls. In OSA patients, SFRP5 level correlated positively with triglyceride level (r=0.447, P=0.005) and negatively with LDL-cholesterol level and HDLcholesterol level (r=?0.472 and P=0.003; r=?0.478 and P=0.002; respectively). SFRP5 level was not found correlating with FBG, AHI, or any of nocturnal hypoxia parameters. After overnight nCPAP treatment, plasma SFRP5 levels of OSA patients did not change significantly (t=1.557, P = 0.148) compared to that of pretreatment.Conclusions In nondiabetic OSA patients, plasma SFRP5 is associated with the lipid profile. However,no correlation was observed between SFRP5 and FBG or sleep parameters. The SFRP5 level of OSA patients did not differ from that of non-OSA individuals in our study.

分泌性卷曲相关蛋白5表达上调对小鼠肝脏糖代谢的影响

分泌性卷曲相关蛋白5(secreted frizzled-related protein 5,SFRP5)是一种抗炎脂肪因子,它与糖尿病密切相关,具有抗糖尿病作用。将8周龄的C57BL/6J小鼠随机分为4组:普食-空载病毒组(SD+Ad-GFP组,n=10)、普食-SFRP5过表达病毒组(SD+Ad-SFRP5组,n=10)、高脂-空载病毒组(HFD+Ad-GFP组,n=10)、高脂-SFRP5过表达病毒组(HFD+Ad-SFRP5组,n=10),各组喂养13周后,利用定量PCR技术及Western-blot技术,分别检测小鼠肝脏糖异生关键酶磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase,PEPCK)和葡萄糖-6-磷酸酶(glucose-6-phosphatase,G6Pase)mRNA及蛋白质水平的变化情况,以及肝脏经典胰岛素信号通路的改变。结果显示:高脂喂养组中,SFRP5表达上调可使肝脏糖异生指标PEPCK和G6Pase的mRNA及蛋白质相对表达水平均降低(P<0.05),而且SFRP5过表达可使肝脏经典胰岛素信号通路指标胰岛素受体(InsR)及蛋白激酶B(AKT)的磷酸化水平增高(P<0.05)。以上结果说明,C57BL/6J小鼠体内过表达SFRP5可能通过降低肝脏糖异生,增强胰岛素信号通路,从而改善机体胰岛素抵抗状态。

不同糖耐量人群血浆分泌型卷曲相关蛋白5水平与胰岛素抵抗的相关性研究

目的探讨不同糖耐量人群血浆分泌型卷曲相关蛋白5(SFRP5)水平变化及与APN、IR的关系。方法采用ELISA测定不同糖耐量人群血浆SFRP5和APN水平,分析血浆SFRP5与APN及相关代谢指标的关系。结果 T2DM、IGT组血浆SFRP5水平低于正常对照(NC)组[(42.99±20.89)vs(49.21±21.52)vs(78.48±23.72)μg/L,P<0.01]。肥胖者血浆SFRP5水平低于非肥胖者[(42.05±19.93)vs(67.72±26.48)μg/L,P<0.01]。相关性分析发现,血浆SFRP5水平与BMI、WHR、体内脂肪百分比(Fat%)、SBP、DBP、FPG、FIns、胰岛素抵抗指数(HOMA-IR)、HbA1c、TG、FFA呈负相关(P均<0.01),与APN、LDL-C呈正相关(P均<0.01)。结论血清SFRP5水平在新诊断T2DM患者和肥胖人群中明显降低,可能与IR有关。

血清分泌型卷曲相关蛋白5与2型糖尿病及颈动脉粥样硬化的相关性研究

目的探讨血清分泌型卷曲相关蛋白5(SFRP5)与T2DM及颈动脉粥样硬化(CAS)的相关性。方法根据颈动脉彩色多普勒超声结果,将56例T2DM患者分成T2DM合并CAS组(CAS组)28例和单纯CAS组(NAS组)28例,同时选取同期正常对照组(NGT组)28名。ELISA测定血清SFRP5浓度。结果 CAS组和NAS组血清SFRP5浓度较NGT组低[(114.36±25.48)vs(48.19±11.82),(43.88±8.19)pg/ml,P<0.01];CAS组与NAS组血清SFRP5比较,差异无统计学意义。Pearson相关分析表明,血清SFRP5与年龄、TG、高敏C反应蛋白(hsC-RP)、FPG、FIns、HOMA-IR、HbA_1c、LDL-C、BMI呈负相关(r=-0.614,-0.160,-0.331,-0.682,-0.467,-0.580,-0.706,-0.339,-0.322,P<0.01),与HDL-C呈正相关(r=0.386,P<0.01),与性别、TC、SBP、DBP无相关性(P>0.05)。多元线性逐步回归结果示,在排除混素因素后,年龄、FIns、HbA_1c是血清SFRP5的影响因素。结论 T2DM患者血清SFRP5浓度较正常人低,SFRP5可能是T2DM的保护因素,或可改善IR,该蛋白的合成可能有助于延缓或逆转T2DM的发生与进展,为T2DM患者的防治提供了新思路。