Decreased hepatic peroxisome proliferator-activated receptor-γ contributes to increased sensitivity to endotoxin in obstructive jaundice

AIM: To investigate the role of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) in increased susceptibility to endotoxin-induced toxicity in rats with bile duct ligation during endotoxemia.METHODS: Male Sprague-Dawley rats were subjected to bile duct ligation (BDL). Sham-operated animals served as controls. DNA binding were determined by polymerase chain reaction, Western blotting analysis,and electrophoretic mobility shift assay, respectively.BDL and sham-operated rats received a non-lethal dose of intraperitoneal lipopolysaccharide (LPS) injection (3 mg/kg, i.p.). Additionally, the potential beneficial effects of the PPAR-γ agonist rosiglitazone were determined in BDL and sham-operated rats treated with a non-lethal dose of LPS. Survival was assessed in BDL rats treated with a non-lethal dose of LPS and in sham-operatedrats treated at a lethal dose of LPS (6 mg/kg, i.p.).RESULTS: PPAR-γ activity in rats undergoing BDL wassignificantly lower than in the sham-controls. Hepatic PPAR-γ gene expression was downregulated at both them RNA and protein levels. In a parallel group, serumlevels of pro-inflammatory cytokines were nearly unde-tectable in the sham-operated rats. When challenged with a non-lethal dose of LPS (3 mg/kg), the BDL ratshad approximately a 2.4-fold increase in serum IL-6,a 2.7 fold increase in serum TNF-α, 2.2-fold increasein serum IL-1 and 4.2-fold increase in serum ALT. Thesurvival rate was significantly lower as compared with that in sham-operated group. Additionally, rosiglitazone significantly reduced the concentration of TNF-α, IL-1β, IL-6 and ALT in sham-operated rats, but not in BDL rats, in response to LPS (3 mg/kg). Also, the survival was improved by rosiglita zone in sham-operated rats challenged with a lethal dose of LPS, but not in BDL rats, even with a non-lethal dose of LPS (3 mg/kg).CONCLUSION: Obstructive jaundice downregulates hepatic PPAR-γ expression, which in turn may contributeto hypersensitivity towards endotoxin.

Peroxisome proliferator-activated receptor-γ 34C>G polymorphism and colorectal cancer risk: A meta-analysis

AIM: To investigate the association between peroxisome proliferator-activated receptor-γ (PPAR-γ ) gene polymorphism 34 C>G and colorectal cancer (CRC),a meta-analysis review was performed in this report.METHODS: A systematic literature search and selection of eligible relevant studies were carried out.Nine independent studies with a total number of 4533 cases and 6483 controls were included in the meta-analysis on the association between polymorphism 34 C>G and CRC.RESULTS: There was no evidence for the association between PPAR-γ 34 C>G and CRC if all of the subjects in the nine studies were included.However,CG + GG showed a marginally significant difference from CC (OR = 0.84,95% CI: 0.69-1.01,P = 0.07) in random-effect model.Stratified meta-analysis indicated that PPAR-γ 34 C>G was associated with colon cancer (OR = 0.8,95% CI: 0.65-0.99,P = 0.04) in random-effect model,and the G allele decreased colon cancer risk.No significant association was observed between PPAR-γ 34 C>G and rectal cancer.CONCLUSION: PPAR-γ 34 C>G is associated with colon cancer risk,but not associated with CRC and rectal cancer risk.

Peroxisome Proliferator-activated Receptor-γ2 Pro12Ala and C-689T Polymorphisms and Haplotypes Affect the Profiles of Coronary Heart Disease in Diabetic Chinese People

Objectives Peroxisome proliferator-activated receptor-γ2（PPARγ2） variant Pro12Ala was demonstrated with risk of coronary heart disease （CHD） and type 2 diabetes mellitus （T2DM）. Another variant C-689T in the promoter was reported with lower receptor activity but lack of reports on association between C-689T and CHD or T2DM. Methods A total of 351 subjects without CHD and T2DM （controls） and 125 patients with CHD and T2DM （cases） were enrolled in our case-control study. Polymerase chain reaction-restricted fragments length polymorphism （PCR-RFLP） was used to detect Pro12Ala and C-689T polymorphisms. And effects on CHD merged with T2DM of the two polymorphisms were analyzed in individual and haplotype analyses. Results In the study, Pro12Pro, Pro12Ala and Ala12Ala genotype frequencies were 92.9%, 6.8% and 0.3% in controls; 92.8%, 7.2% and 0.0% in cases respectively whilst CC, CT and TT genotype frequencies were 93.4%, 6.3% and 0.3% in controls; 92.8%, 7.2% and 0.0% in cases respectively. Pro12Ala and C-689T polymorphisms were in strong linkage disequilibrium （D＇=0.81, P=0.000） and the observed haplotype frequency of Pro-C, Pro-T, Ala-C and Ala-T was 0.957, 0.006, 0.008 and 0.028 respectively. No significant associations were detected between the two polymorphisms and CHD merged with T2DM in either individual or haplotype analyses. In subjects with obesity [body mass index （BMI）≥25 kg/m^2], we found that both Pro12Ala and C-689T polymorphisms were associated with BMI. In haplotype analyses, we found that Pro12Ala and C-689T haplotypes had associations with systolic blood pressure in total population, with BMI, waist circle and total cholesterol（TC） in obesity subgroup and with fasting blood glucose and TC in males. Conclusions PPARγ2 Pro12Ala and C-689T polymorphisms and haplotypes affect the profiles of CHD merged with T2DM in Chinese Han people.

Peroxisome proliferator-activated receptor gamma as a therapeutic target for hepatocellular carcinoma:Experimental and clinical scenarios

Hepatocellular carcinoma(HCC)is the most common type of liver cancer worldwide.Viral hepatitis is a significant risk factor for HCC,although metabolic syndrome and diabetes are more frequently associated with the HCC.With increasing prevalence,there is expected to be>1 million cases annually by 2025.Therefore,there is an urgent need to establish potential therapeutic targets to cure this disease.Peroxisome-proliferator-activated receptor gamma(PPARγ)is a ligand-activated transcription factor that plays a crucial role in the pathophysiology of HCC.Many synthetic agonists of PPARγsuppress HCC in experimental studies and clinical trials.These synthetic agonists have shown promising results by inducing cell cycle arrest and apoptosis in HCC cells and preventing the invasion and metastasis of HCC.However,some synthetic agonists also pose severe side effects in addition to their therapeutic efficacy.Thus natural PPARγagonists can be an alternative to exploit this potential target for HCC treatment.In this review,the regulatory role of PPARγin the pathogenesis of HCC is elucidated.Furthermore,the experimental and clinical scenario of both synthetic and natural PPARγagonists against HCC is discussed.Most of the available literature advocates PPARγas a potential therapeutic target for the treatment of HCC.

Differential Mechanisms of the Effect of Peroxisome Proliferator-Activated Receptor Gamma Agonists on Bleomycin-Induced Lung Fibrosis

Background and Objectives: Peroxisome proliferator-activated receptor-g (PPAR-g) is a nuclear receptor whose activation regulates inflammation and fibrosis in various organs. We aimed to investigate the effect of two PPAR-g ligands, telmisartan and rosiglitazone, on lung injury and fibrosis induced by intratracheal bleomycin (BLM). Methods: Lung injury and fibrosis was induced in female C57Bl/6 mice by intratracheal instillation of 1.0 mg/kg of BLM. Some of the animals received rosiglitazone intraperitoneally or telmisartan in drinking water. Bronchoalveolar lavage (BAL) was performed 2, 7, 14 or 21 days after BLM instillation for cell counting and measurement of mediators in the lung. In a separate series, the lungs were sampled for collagen assay and histopathological evaluation. Results: Treatment with rosiglitazone or telmisartan significantly attenuated the BLM-induced increases in lung collagen content, pathological score, and inflammatory cells in BAL fluid. Rosiglitazone significantly suppressed BLM-induced elevation of TGF-b1, MCP-1, and IL-6 levels in the lung. In contrast, telmisartan made no changes in these cytokines, whereas it mitigated the BLM-induced increase in prostaglandin F2a in the lung. Higher concentrations of rosiglitazone and telmisartan attenuated proliferation of lung fibroblasts in vitro. Conclusions: Two PPAR-g ligands, rosiglitazone and telmisartan, exert protective effects on BLM-induced lung fibrosis through the suppression of different profibrotic mediators.

Potential effects of curcumin on peroxisome proliferatoractivated receptor-γ in vitro and in vivo

Natural peroxisome proliferator-activated receptor-γ(PPAR-γ) agonists are found in food and may be important for health through their anti-inflammatory properties. Curcumin(Cur) is a bright yellow spice, derived from the rhizome of Curcuma longa Linn. It has been shown to have many biological properties that appear to operate through diverse mechanisms. Some of these potentially beneficial effects of Cur are due to activation of the nuclear transcription factor PPAR-γ. It is reported(using in vitro and in vivo models) that Cur plays a potential role against several diseases. In this review article, we present the current literature on the effects of Cur on the modulation of inflammatory processes that are mediated through PPAR-γ.

Construction and identification of the recombinant adenovirus vector carrying a small interfering RNA targeting the peroxisome proliferator-activated receptor-γ

Background Steroid-induced osteonecrosis of the femoral head （ONFH） is a common clinical disease,with a high disability rate.At present,efficient prevention and treatment of steroid-induced ONFH is still lacking.The peroxisome proliferator-activated receptor-γ （PPARγ） is recognized as an important pathogenic gene for the development of steroid-induced ONFH.RNA interference （RNAi） is a tool for functional gene analysis,which has been successfully used to down-regulate the levels of specific target proteins.Therefore,down-regulation of PPARγ expression by RNAi may prevent the incidence of steroid-induced ONFH.Methods According to the principles of siRNA design,three duplex siRNA sequences （971-989,1253-1271 and 1367-1385） derived from the PPARy gene （NM_001082148） were synthesized.These duplexes were annealed,purified and ligated into 1.0-cytomegalovirus （CMV） shuttle vector.The shuttle vector was transfected into HEK293 cells.The HEK293 generated recombinant adenovirus vector carrying PPARγ siRNA sequences was purified and the titer of recombinant adenovirus was determined.Results After the annealing of single-strand DNA oligo encoding short hairpin RNA （shRNA） sequences,products were identified by gel electrophoresis.These products were ligated into the 1.0-CMV shuttle vector and the recombinant shuttle vectors 1.0-CMV-971,1.0-CMV-1253 and 1.0-CMV-1367 were constructed.These sequences of these recombinant vectors were confirmed.We then successfully constructed the recombinant adenovirus vector carrying siRNA targeting PPARγ.After purification,the virus titer was higher than 1010 plaque forming unit （PFU）/ml.Conclusion In this study,three recombinant adenovirus shuttle vectors carrying siRNA targeting PPARγ,including shuttle vectors 1.0-CMV-971,1.0-CMV-1253 and 1.0-CMV-1367,were successfully constructed and high titers of recombinant adenovirus were obtained.

Inhibition of peroxisome proliferator-activated receptor-γ in steroid-induced adipogenic differentiation of the bone marrow mesenchymal stem cells of rabbit using small interference RNA

Background Steroids inhibit osteogenic differentiation and decrease bone formation while concomitantly inducing adipose deposition in osteocytes.This leads to the fatty degeneration and necrosis of bone cells commonly seen in osteonecrosis of the femoral head.The peroxisome proliferator-activated receptor-γ （PPARγ） is an adipogenic transcription factor linked to the development of this disease and responsible for inducing adipogenesis over osteogenesis in bone marrow mesenchymal stem cells （BMSCs）.The aim of this study was to assess whether adipogenic differentiation could be suppressed,and thus osteogenic potential retained,by inhibiting PPARy expression in BMSCs.Methods Cells from the bone marrow of New Zealand rabbits were treated with 10-7 mol/L dexamethasone and infected with one of three small interference RNA （siRNA） adenovirus vectors （S1,S2,and S3） or non-targeting control siRNA （Con） and compared with dexamethasone-treated （model） and untreated （normal） cells.Cells were grown for 21 days and stained with Sudan Ⅲ for adipocyte formation.At various time points,cells were also assessed for changes in PPARγ,osteocalcin （OC）,Runx2,alkaline phosphatase （ALP） activity,and triglyceride （TG） content.Results Dexamethasone-treated model and control groups showed a significant increase in fatty acid-positive staining,which was inhibited in cells treated with PPARγ siRNA-treated,similar to normal untreated cells.All three siRNA groups significantly inhibited PPARγ mRNA and protein,adipocyte number,and TG content compared with the dexamethasonetreated model and control groups,matching that seen in normal cells.OC and Runx2 mRNA and protein,as well as ALP activity,were significantly higher in cells treated with siRNA against PPARγ,similar to that seen in the normal cells.These osteogenic markers were significantly lower in the dexamethasone-treated cell cultures.Conclusions The siRNA adenovirus vector targeting PPARγ can efficiently inhibit steroid-induced adipogenic differentiation in rabbit BMSCs and retain their osteogenic differentiation potential.

High density lipoprotein suppresses lipoprotein associated phospholipase A2 in human monocytes-derived macrophages through peroxisome proliferator-activated receptor-γ pathway

Background Lipoprotein-associated phospholipase A2 （Lp-PLA2） is mainly secreted by macrophages, serving as a specific marker of atherosclerotic plaque and exerting pro-atherogenic effects. It is known that high-density lipoprotein （HDL） plays an important role against atherosclerosis by inhibiting pro-inflammatory factors, however, the relationship between HDL and Lp-PLA2 remains elusive. Methods In this study, reverse transcription-polymerase chain reaction （RT-PCR）, Western blotting, and a platelet-activating factor （PAF） acetylhydrolase assay were performed to determine the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages upon HDL treatment of different concentrations and durations. To investigate the underlying mechanism of HDL-induced Lp-PLA2 action, pioglitazone, a peroxisome proliferator-activated receptor-γ （PPARy） ligand, was introduced to human monocyte-derived macrophages and mRNA and protein levels of Lp-PLA2, as well as its activity, were determined. Results Lp-PLA2 mRNA levels, protein expression and activity were significantly inhibited in response to HDL treatment in a dose and time dependent manner in human monocyte-derived macrophages. Pioglitazone treatment （1-10 ng/ml） upregulated the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages, while the effects were markedly reversed by HDL. In addition, pioglitazone resulted in a significant increase in PPARy phosphorylation in human monocyte-derived macrophages, which could be inhibited by HDL. Conclusion These findings indicate that HDL suppresses the expression and activity of Lp-PLA2 in human monocyte-derived macrophages, and the underlying mechanisms may be mediated through the PPARγ pathway.

Activation of G-protein-coupled receptor 39 reduces neuropathic pain in a rat model

Activated G-protein-coupled receptor 39(GPR39)has been shown to attenuate inflammation by interacting with sirtuin 1(SIRT1)and peroxisome proliferator-activated receptor-γcoactivator 1α(PGC-1α).However,whether GPR39 attenuates neuropathic pain remains unclear.In this study,we established a Sprague-Dawley rat model of spared nerve injury-induced neuropathic pain and found that GPR39 expression was significantly decreased in neurons and microglia in the spinal dorsal horn compared with sham-operated rats.Intrathecal injection of TC-G 1008,a specific agonist of GPR39,significantly alleviated mechanical allodynia in the rats with spared nerve injury,improved spinal cord mitochondrial biogenesis,and alleviated neuroinflammation.These changes were abolished by GPR39 small interfering RNA(siRNA),Ex-527(SIRT1 inhibitor),and PGC-1αsiRNA.Taken together,these findings show that GPR39 activation ameliorates mechanical allodynia by activating the SIRT1/PGC-1αpathway in rats with spared nerve injury.

神经干细胞特异性PPARγ基因敲除小鼠模型的制备与鉴定

目的制备与鉴定神经干细胞特异性PPARγ基因敲除小鼠模型。方法将引进的2种转基因小鼠B6.PPARγloxp/loxp、B6.Nestin-Cre进行饲养并杂交繁殖,将子一代小鼠与B6.PPARγloxp/loxp小鼠回交获得子二代小鼠,提取子二代小鼠的基因组DNA,利用PCR方法扩增Cre和loxp基因片段,并进行琼脂糖凝胶电泳检测。选取基因型为B6.PPARγloxp/loxp.Nestin-Cre(KO)的小鼠即为神经干细胞特异性敲除PPARγ的敲除小鼠,另选基因型为B6.PPARγloxp/loxp(loxp)作为对照组小鼠。应用RT-PCR、实时荧光定量PCR方法鉴定神经干细胞特异性敲除PPARγ的敲除小鼠。结果敲除小鼠在基因鉴定时可以扩增得到PPARγloxp和Cre两个条带,在mRNA表型检测时脑内PPARγ表达显著低于对照组小鼠。成功获得神经干细胞敲除PPARγ基因的敲除小鼠。所购2种转基因小鼠均有繁殖能力,其繁殖符合孟德尔遗传规律。结论基于loxp-Cre系统成功构建神经干细胞特异性敲除PPARγ的基因敲除小鼠,为进一步的神经系统疾病的治疗及其机制研究提供模型基础。

Application of the back-error propagation artificial neural network(BPANN) on genetic variants in the PPAR-γ and RXR-α gene and risk of metabolic syndrome in a Chinese Han population

This study was aimed to explore the associations between the combined effects of several polymorphisms in the PPAR-γ and RXR-α gene and environmental factors with the risk of metabolic syndrome by back-error propaga- tion artificial neural network （BPANN）. We established the model based on data gathered from metabolic syndrome patients （n = 1012） and normal controls （n = 1069） by BPANN. Mean impact value （MIV） for each input variable was calculated and the sequence of factors was sorted according to their absolute MIVs. Generalized multifactor dimensionality reduction （GMDR） confirmed a joint effect of PPAR-9＂ and RXR-a based on the results from BPANN. By BPANN analysis, the sequences according to the importance of metabolic syndrome risk fac- tors were in the order of body mass index （BMI）, serum adiponectin, rs4240711, gender, rs4842194, family history of type 2 diabetes, rs2920502, physical activity, alcohol drinking, rs3856806, family history of hypertension, rs1045570, rs6537944, age, rs17817276, family history of hyperlipidemia, smoking, rs1801282 and rs3132291. However, no polymorphism was statistically significant in multiple logistic regression analysis. After controlling for environmental factors, A1, A2, B1 and B2 （rs4240711, rs4842194, rs2920502 and rs3856806） models were the best models （cross-validation consistency 10/10, P = 0.0107） with the GMDR method. In conclusion, the interaction of the PPAR-γ and RXR-α gene could play a role in susceptibility to metabolic syndrome. A more realistic model is obtained by using BPANN to screen out determinants of diseases of multiple etiologies like metabolic syndrome.

Hepatic lipid homeostasis by peroxisome proliferator-activated receptor gamma 2

Peroxisome proliferator-activated receptor gamma(PPARγor PPARG)is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily.It plays a master role in the differentiation and proliferation of adipose tissues.It has two major isoforms,PPARγ1 and PPARγ2,encoded from a single gene using two separate promoters and alternative splicing.Among them,PPARγ2 is most abundantly expressed in adipocytes and plays major adipogenic and lipogenic roles in the tissue.Furthermore,it has been shown that PPARγ2 is also expressed in the liver,specifically in hepatocytes,and its expression level positively correlates with fat accumulation induced by pathological conditions such as obesity and diabetes.Knockout of the hepatic Pparg gene ameliorates hepatic steatosis induced by diet or genetic manipulations.Transcriptional activation of Pparg in the liver induces the adipogenic program to store fatty acids in lipid droplets as observed in adipocytes.Understanding how the hepatic Pparg gene expression is regulated will help develop preventative and therapeutic treatments for non-alcoholic fatty liver disease(NAFLD).Due to the potential adverse effect of hepatic Pparg gene deletion on peripheral tissue functions,therapeutic interventions that target PPAR g for fatty liver diseases require fine-tuning of this gene's expression and transcriptional activity。

Myeloid peroxisome proliferator-activated receptor α deficiency accelerates liver regeneration via IL-6/STAT3 pathway after 2/3 partial hepatectomy in mice

Background:Liver regeneration is a fundamental process for sustained body homeostasis and liver function recovery after injury.Emerging evidence demonstrates that myeloid cells play a critical role in liver regeneration by secreting cytokines and growth factors.Peroxisome proliferator-activated receptorα(PPARα),the target of clinical lipid-lowering fibrate drugs,regulates cell metabolism,proliferation,and survival.However,the role of myeloid PPARαin partial hepatectomy(PHx)-induced liver regeneration remains unknown.Methods:Myeloid-specific PPARa-deficient(Ppara^(Mye−/−))mice and the littermate controls(Ppara^(fl/fl))were subjected to sham or 2/3 PHx to induce liver regeneration.Hepatocyte proliferation and mitosis were assessed by immunohistochemical(IHC)staining for 5-bromo-2'-deoxyuridine(BrdU)and Ki67 as well as hematoxylin and eosin(H&E)staining.Macrophage and neutrophil infiltration into livers were reflected by IHC staining for galectin-3 and myeloperoxidase(MPO)as well as flow cytometry analysis.Macrophage migration ability was evaluated by transwell assay.The mRNA levels for cell cycle or inflammation-related genes were measured by quantitative real-time RT-PCR(qPCR).The protein levels of cell proliferation related protein and phosphorylated signal transducer and activator of transcription 3(STAT3)were detected by Western blotting.Results:Ppara^(Mye−/−)mice showed enhanced hepatocyte proliferation and mitosis at 32 h after PHx compared with Ppara^(fl/fl)mice,which was consistent with increased proliferating cell nuclear antigen(Pcna)mRNA and cyclinD1(CYCD1)protein levels in Ppara^(Mye−/−)mice at 32 h after PHx,indicating an accelerated liver regeneration in Ppara^(Mye−/−)mice.IHC staining showed that macrophages and neutrophils were increased in Ppara^(Mye−/−)liver at 32 h after PHx.Livers of Ppara^(Mye−/−)mice also showed an enhanced infiltration of M1 macrophages at 32 h after PHx.In vitro,Ppara-deficient bone marrow-derived macrophages(BMDMs)exhibited markedly enhanced migratory capacity and upregulated M1 genes Il6 and Tnfa but downregulated M2 gene Arg1 expressions.Furthermore,the phosphorylation of STAT3,a key transcript factor mediating IL6-promoted hepatocyte survival and proliferation,was reinforced in the liver of Ppara^(Mye−/−)mice after PHx.Conclusions:This study provides evidence that myeloid PPARαdeficiency accelerates PHx-induced liver regeneration via macrophage polarization and consequent IL-6/STAT3 activation,thus providing a potential target for manipulating liver regeneration.

Targeting PPARαin low ambient temperature exposure-induced cardiac dysfunction and remodeling

The present study demonstrates that the down-regulation of peroxisome proliferator-activated receptor-α(PPARα)results in chronic low ambient temperature(LT)exposure-induced cardiac dysfunction and remodeling,emphasizing the therapeutic potential of PPARαactivation strategies(e.g.,fenofibrate treatment)in LT-associated cardiac injury.

Design,synthesis and in vitro evaluation of a series thiazolidinediones analogs as PPAR modulators

A series of thiazolidinediones analogs, as PPAR modulators, were designed, synthesized and evaluated in vitro.

LXR, PPAR<i>γ</i>, and PPAR<i>δ</i>Agonists Are Not Sufficient to Demonstrate Therapeutic Potential against Mouse Model of Systemic Lupus Erythematosus

Aim: We aimed to investigate whether the agonists for liver X receptor (LXR) ameliorate lupus-like phenotypes in mice mediated by the clearance of apoptotic cells, and compare with peroxisome proliferator-activated receptor (PPAR) γ plus PPARδ agonists, which also facilitate the clearance of apoptotic cells and exert anti-inflammatory effects in systemic lupus erythematosus (SLE). Methods: We investigated the efficacy of LXR agonist (GW3965) or dual treatment of PPARγ (pioglitazone) and PPARδ (GW0742) agonists in SLE animal models, female MRL/MpJ-Fas/J mice and BALB/cAJcl mice treated with pristane. The data were analyzed with one-way analysis of variance and Tukey’s honestly significant difference tests. Results: The treatment with LXR or PPARγ/δ agonists did not significantly alter the swelling of lymph nodes, ds-DNA production, albuminuria, histological score of glomerular lesions, and mRNA expression of target genes including Abca1, C1qa, Icam1, Mertk and Tnf. Conclusion: LXR or PPARγ/δ agonists targeting the impaired clearance for apoptosis cells may not be efficient in the remission induction therapy in SLE.

脓毒症研究新进展

脓毒症正逐渐成为全世界严峻的医学问题，脓毒症的发病率与病死率逐年上升，然而脓毒症的临床治疗并未取得理想的效果，可能归咎于其复杂的病理生理过程和尚未完全揭示的发病机制。近年来研究发现，氧化还原反应失衡、过氧化物酶增生物激活受体的功能下降、补体的激活与释放、神经调节紊乱、免疫麻痹等参与了脓毒症的发病机制，有助于我们对脓毒症的进一步认识。至此，本文将对这些新机制加以综述。

Effect of Marine Collagen Peptides on Markers of Metabolic Nuclear Receptors in Type 2 Diabetic Patients with/without Hypertension

Objective To explore Effects of marine collagen peptides （MCPs） on markers of metablic nuclear receptors, i.e peroxisome proliferator-activated receptor （PPARs）, liver X receptor （LXRs） and farnesoid X receptor （FXRs） in type 2 diabetic patients with/without hypertension. Method Study population consisted of 200 type 2 diabetic patients with/without hypertension and 50 healthy subjects, all of whom were randomly assigned to MCPs-treated diabetics （n=50）, placebo-treated diabetics （n=50）, MCPs-treated diabetics with hypertension （n=50）, placebo-treated diabetics with hypertension （n=50）, and healthy controls （n=50）. MCPs or placebo （water-soluble starch） were given daily before breakfast and bedtime over three months. Levels of free fatty acid, cytochrome P450, leptin, resistin, adiponectin, bradykinin, NO, and Prostacyclin were determined before intervention, and 1.5 months, and 3 months after intervention. Hypoglycemia and the endpoint events during the study were recorded and compared among the study groups. Result At the end of the study period, MCPs-treated patients showed marked improvement compared with patients receiving placebo. The protection exerted by MCPs seemed more profound in diabetics than in diabetics with hypertension. In particular, after MCPs intervention, levels of free fatty acid, hs-CRP, resistin, Prostacyclin decreased significantly in diabetics and tended to decrease in diabetic and hypertensive patients whereas levels of cytochrome P450, leptin, NO tended to decrease in diabetics with/without hypertension. Meanwhile, levels of adiponectin and bradykinin rose markedly in diabetics following MCPs administration. Conclusion MCPs could offer protection against diabetes and hypertension by affecting levels of molecules involved in diabetic and hypertensive pathogenesis. Regulation on metabolic nuclear receptors by MCPs may be the possible underlying mechanism for its observed effects in the study. Further study into its action may shed light on development of new drugs based on bioactive peptides from marine sources.

Neuroprotection mediated by the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage

The Wnt/Frizzled signaling pathway participates in many inflammation-linked diseases. However, the inflammatory response mediated by the Wnt/Frizzled signaling pathway in experimental subarachnoid hemorrhage has not been thoroughly investigated. Consequently, in this study, we examined the potential role of the Wnt/Frizzled signaling pathway in early brain injury in rat models of subarachnoid hemorrhage.Simultaneously, possible neuroprotective mechanisms were also investigated. Experimental subarachnoid hemorrhage rat models were induced by injecting autologous blood into the prechiasmatic cistern. Experiment 1 was designed to examine expression of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. In total, 42 adult rats were divided into sham(injection of equivalent volume of saline), 6-, 12-, 24-, 48-, 72-hour, and 1-week subarachnoid hemorrhage groups. Experiment 2 was designed to examine neuroprotective mechanisms of the Wnt/Frizzled signaling pathway in early brain injury induced by subarachnoid hemorrhage. Rats were treated with recombinant human Wnt1(rhwnt1), small interfering Wnt1(siwnt1) RNA, and monoclonal antibody of Frizzled1(anti-Frizzled1) at 48 hours after subarachnoid hemorrhage. Expression levels of Wnt1, Frizzled1, β-catenin, peroxisome proliferator-activated receptor-γ, CD36, and active nuclear factor-κB were examined by western blot assay and immunofluorescence staining. Microglia type conversion and inflammatory cytokine levels in brain tissue were examined by immunofluorescence staining and enzyme-linked immunosorbent assay. Our results show that compared with the sham group, expression levels of Wnt1, Frizzled1, and β-catenin were low and reduced to a minimum at 48 hours, gradually returning to baseline at 1 week after subarachnoid hemorrhage. rhwnt1 treatment markedly increased Wnt1 expression and alleviated subarachnoid hemorrhage-induced early brain injury(within 72 hours), including cortical cell apoptosis, brain edema, and neurobehavioral deficits, accompanied by increasing protein levels of β-catenin, CD36, and peroxisome proliferator-activated receptor-γ and decreasing protein levels of nuclear factor-κB. Of note, rhwnt1 promoted M2-type microglia conversion and inhibited release of inflammatory cytokines(interleukin-1β, interleukin-6, and tumor necrosis factor-α). In contrast, siwnt1 RNA and anti-Frizzled1 treatment both resulted in an opposite effect. In conclusion, the Wnt/Frizzled1 signaling pathway may participate in subarachnoid hemorrhage-induced early brain injury via inhibiting the inflammatory response, including regulating microglia type conversion and decreasing inflammatory cytokine release. The study was approved by the Animal Ethics Committee of Anhui Medical University and First Affiliated Hospital of USTC,Division of Life Sciences and Medicine, University of Science and Technology of China(approval No. LLSC-20180202) in May 2017.