Effect of Diabetes-Mediated Pericyte Injury on Blood-Spinal Cord Barrier Destruction after Spinal Cord Injury / 中国生物化学与分子生物学报

Diabetes mellitus (DM) is a common and chronic metabolic disease, which disturbs the internal environment, and then causes series of acute or chronic complications. Chronic hyperglycemia induces macroangiopathy and microangiopathy, which is synergistically regulated by intricate molecular mechanisms, including inflammatory responses, intracellular stress, pyrotosis and ferroptosis. DM hinders the repair of blood-spinal cord barrier (BSCB) after spinal cord injury (SCI) and aggravates the neurological damage. Pericytes are the main component of neurovascular units, which regulates angiogenesis, capillary blood flow, and BSCB permeability. After SCI, the BSCB is destroyed, the coverage rate of pericytes is significantly reduced. Then, it greatly affects the normal function of blood vessels. Diabetes not only plays a role in regulating the contraction phenotype and signal transduction of pericytes, but also changes the secretion genome spectrum of pericytes, and then affects the normal function of pericytes. Moreover, it has also been shown that diabetes promotes the loss of pericytes after SCI. This review systematically describes the regulatory effect of diabetes on pericytes in the vascular system, and the effect of diabetes mediated-pericyte injury on BSCB after SCI.

The Role of PI3K / AKT / FOXO Signaling Pathway-mediated Autophagy in Diabetes-associated Cognitive Dysfunction / 中国生物化学与分子生物学报

Diabetes‚ a metabolic disease characterized by hyperglycemia‚ can cause central nerve system damage‚ lead to alteration of the neuronal structure and function‚ and consequently induce cognitive dysfunction. Recently‚ diabetes-associated cognitive dysfunction (DACD) and its molecular mechanism have become a research frontier. The phospoinositide 3 kinase/ protein kinase B/ Forkhead box O (PI3K/ PKB/ FOXO) signaling pathway is an important upstream regulatory mechanism for autophagy. Here we review the role of the PI3K/ AKT/ FOXO signaling pathway in the regulation of Gs‚ Bnip3 and Spk2 gene expressions. GS regulates the Gln-mTORC1 pathway and thus activates autophagy; BNIP3 enhances LC3 expression and promotes autophagy. Moreover‚ the AMPK-FOXO3a-mTORC1 signaling pathway is also an important pathway that involved in the regulation of autophagy. These studies suggest that FOXO3a may be a key target for the treatment of DACD. This review aims to provide a theoretical basis and molecular target for the clinical treatment of DACD and it related drug development.

Prevalence of CYP2C19 gene mutations in patients with coronary heart disease and its biological activation effect in clopidogrel antiplatelet response / 中华心血管病杂志

Objective: The purpose of this study was to investigate the effects of CYP2C19 gene mutations on clopidogrel antiplatelet activity in the patients with coronary heart disease treated by percutaneous coronary intervention. Methods: Patients with coronary heart disease, who hospitalized in the Second Affiliated Hospital of Nanchang University from March 2011 to June 2019, and healthy individuals with matching genetic background, gender, and age as controls were included in this study. Basic clinical data were analyzed and blood samples of all research subjects were obtained for extraction of DNA, and Sanger first-generation sequencing method was used to detect CYP2C19 gene mutation from full exon and exon and intron junction. CYP2C19 gene variations in patients with coronary heart disease were compared with the 1000 Genomes Browse database and the sequencing results of healthy controls to determine whether the gene variation was a genetic mutation or a genetic polymorphism. After that, PolyPhen-2 prediction software was used to analyze the harmfulness of gene mutations to predict the effect of mutations on protein function. The same dose of CYP2C19 wild-type plasmid and the CYP2C19 gene mutant plasmids were transfected into human normal liver cells HL-7702. After transfection of 24 h, the expression of CYP2C19 protease in each group was detected. The liver S9 protein was incubated with clopidogrel, acted on platelets to detect the platelet aggregation rate and the activity of human vasodilator-activated phosphoprotein (VASP). Results: A total of 1 493 patients with coronary heart disease (59.36%) were enrolled, the average age was (64.5±10.4) years old, of which 1 129 were male (75.62%). Meanwhile, 1 022 healthy physical examination volunteers (40.64%) were enrolled, and the average age was (64.1±11.0) years old, of which 778 were male (76.13%). A total of 5 gene mutations of CYP2C19 gene were identified in 12 patients (0.80%), namely, 4 known mutations T130K (1 case), M136K (6 cases), N277K (3 cases), V472I (1 case) and one new mutation G27V (1 case), no corresponding gene mutation was found in healthy controls. It was found that T130K and M136K were probably damaging, G27V was possibly damaging, and N277K and V472I were benign mutations. In vitro, we demonstrated that the platelet aggregation rate of the M136K gene mutation group was 24.83% lower than that of the wild type (59.58% vs. 34.75%; P<0.05), and the phosphorylated VASP level was 23.0% higher than that of the wild type (1.0 vs. 1.23; P<0.05). However, the platelet aggregation rate and phosphorylated VASP level were similar between of G27V, T130K, N277K, V472I gene mutation groups and wild type group (P>0.05). Conclusions: In this study, 5 gene mutations are defined in patients with coronary heart disease, namely G27V, T130K, M136K, N277K, V472I. In vitro functional studies show that CYP2C19 gene mutation M136K, as a gain-of-function gene mutation, can enhance the activation of CYP2C19 enzyme on clopidogrel, thereby inhibiting the platelet aggregation rate.

Anabolic-androgenic steroids and cardiovascular risk / 中华医学杂志(英文版)

Objective@#Anabolic-androgenic steroids (AAS) represents a group of synthetic testosterone derivatives that play an important role in clinical treatment. These drugs are widely abused among the general public to increase lean weight and improve athletic performance. It has been reported that AAS use can produce many adverse effects, especially the occurrence of cardiovascular risk. Although there are many related studies, there has been no consensus on AAS use and cardiovascular risk. The present study was to review the effect of AAS on the cardiovascular system.@*Data sources@#The data in this review were obtained from articles included in PubMed and the National Center for Biotechnology Information database.@*Study selection@#Original articles, case reports, and systematic reviews about AAS were selected for the article.@*Results@#The use/abuse of AAS is correlated with higher cardiovascular risks, and many AAS users/abusers had cardiovascular diseases. However, there are many confounding factors in the studies that explored the causality between AAS intake and disease development, and additional studies are required to determine AAS toxicity.@*Conclusion@#AAS produces toxic effects on the cardiovascular system, and it is necessary to ensure that more people know this about AAS, including medical personnel.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study / 中华医学杂志(英文版)

Background@#The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.@*Methods@#A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.@*Results@#During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 109/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99–1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 109/L. For leukocyte counts < 6.75 × 109/L, the HR (95% CI) was 0.88 (0.69–1.13), and for leukocyte counts ≥ 6.75 × 109/L, the HR (95% CI) was 1.28 (1.09–1.51).@*Conclusion@#This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.@*Clinical trial registration@#NCT02414035, https://clinicaltrials.gov.

Anabolic-androgenic steroids and cardiovascular risk / 中华医学杂志(英文版)

OBJECTIVE@#Anabolic-androgenic steroids (AAS) represents a group of synthetic testosterone derivatives that play an important role in clinical treatment. These drugs are widely abused among the general public to increase lean weight and improve athletic performance. It has been reported that AAS use can produce many adverse effects, especially the occurrence of cardiovascular risk. Although there are many related studies, there has been no consensus on AAS use and cardiovascular risk. The present study was to review the effect of AAS on the cardiovascular system.@*DATA SOURCES@#The data in this review were obtained from articles included in PubMed and the National Center for Biotechnology Information database.@*STUDY SELECTION@#Original articles, case reports, and systematic reviews about AAS were selected for the article.@*RESULTS@#The use/abuse of AAS is correlated with higher cardiovascular risks, and many AAS users/abusers had cardiovascular diseases. However, there are many confounding factors in the studies that explored the causality between AAS intake and disease development, and additional studies are required to determine AAS toxicity.@*CONCLUSION@#AAS produces toxic effects on the cardiovascular system, and it is necessary to ensure that more people know this about AAS, including medical personnel.

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study / 中华医学杂志(英文版)

BACKGROUND@#The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran.@*METHODS@#A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed.@*RESULTS@#During 6-month follow-up, 87 participants occurred bleeding events. For every 1 × 10/L increase in leukocyte count, the risk of bleeding increased by 11% (hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99-1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75 × 10/L. For leukocyte counts < 6.75 × 10/L, the HR (95% CI) was 0.88 (0.69-1.13), and for leukocyte counts ≥ 6.75 × 10/L, the HR (95% CI) was 1.28 (1.09-1.51).@*CONCLUSION@#This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.@*CLINICAL TRIAL REGISTRATION@#NCT02414035, https://clinicaltrials.gov.

A role for long-chain acyl-CoA synthetase-4 (ACSL4) in diet-induced phospholipid remodeling and obesity-associated adipocyte dysfunction.

OBJECTIVE: Regulation of fatty acid (FA) metabolism is central to adipocyte dysfunction during diet-induced obesity (DIO). Long-chain acyl-CoA synthetase-4 (ACSL4) has been hypothesized to modulate the metabolic fates of polyunsaturated FA (PUFA), including arachidonic acid (AA), but the in vivo actions of ACSL4 are unknown. The purpose of our studies was to determine the in vivo role of adipocyte ACSL4 in regulating obesity-associated adipocyte dysfunction. METHODS: We developed a novel mouse model with adipocyte-specific ablation of ACSL4 (Ad-KO) using loxP Cre recombinase technology. Metabolic phenotyping of Ad-KO mice relative to their floxed littermates (ACSL4floxed) was performed, including body weight and body composition over time; insulin and glucose tolerance tests; and energy expenditure, activity, and food intake in metabolic cages. Adipocytes were isolated for ex vivo adipocyte oxygen consumption by Clark electrode and lipidomics analysis. In vitro adipocyte analysis including oxygen consumption by Seahorse and real-time PCR analysis were performed to confirm our in vivo findings. RESULTS: Ad-KO mice were protected against DIO, adipocyte death, and metabolic dysfunction. Adipocytes from Ad-KO mice fed high-fat diet (HFD) had reduced incorporation of AA into phospholipids (PL), free AA, and levels of the AA lipid peroxidation product 4-hydroxynonenal (4-HNE). Additionally, adipocytes from Ad-KO mice fed HFD had reduced p53 activation and increased adipocyte oxygen consumption (OCR), which we demonstrated are direct effects of 4-HNE on adipocytes in vitro. CONCLUSION: These studies are the first to elucidate ACSL4's in vivo actions to regulate the incorporation of AA into PL and downstream effects on DIO-associated adipocyte dysfunction. By reducing the incorporation of AA into PL and free fatty acid pools in adipocytes, Ad-KO mice were significantly protected against HFD-induced increases in adipose and liver fat accumulation, adipocyte death, gonadal white adipose tissue (gWAT) inflammation, and insulin resistance (IR). Additionally, deficiency of adipocyte ACSL4 expression in mice fed a HFD resulted in increased gWAT adipocyte OCR and whole body energy expenditure (EE).

Role of HSP22 in atherosclerosis induced by high-fat diet and effects of statin / 中国病理生理杂志

AIM:To evaluate the role of heat shock protein 22(HSP22)in atherosclerosis(AS)induced by high-fat diet and in the intervention with atorvastatin(Ator).METHODS: Total 3 groups of 8 ~9-week-old ApoE-/-, HSP22-/-ApoE-/-and HSP22 +ApoE-/-male mice were used,with 18 mice in each group.After 1 week of adaptive feeding, the mice in each group were randomly divided into 2 subgroups: control group, and Ator group, HSP22 knockout group (KO group)and HSP22 knockout with Ator treatment group(KO+Ator group),and HSP22 overexpression group(Tg group)and HSP22 overexpression with Ator treatment group(Tg+Ator group).Atro at 10 mg· kg-1-d-1was administered to the mice in all Ator groups from the 5th week.The mice in the control groups were given saline.All these mice were fed for 13 weeks.Oil red O staining and HE staining of the aortic wall of the mice were used to measure the atherosclerotic le-sion burdens.The protein levels of HSP22,NF-κB, eNOS, ICAM-1 and IL-6 in the aorta and serum were examined by Western blot,immunohistochemistry and ELISA.RESULTS:Aortic Oil red O staining and HE staining showed that the relative area of aorta plaque in Tg group was less than that in KO group(P<0.05).The protein expression of HSP22 in Tg group was significantly higher than that in control group and KO group,and its expression in control group was signifi-cantly higher than that in KO group.The protein expression of eNOS in Tg group and control group was significantly higher than that in KO group.The protein expression of NF-κB and ICAM-1 in control group was significantly decreased as com-pared with KO group,and their expression was significantly higher than that in Tg group.No difference of serum IL-6 level was found among Tg group,KO group and control group.CONCLUSION:HSP22 gene deletion up-regulates the expres-sion of NF-κB and ICAM-1,and down-regulates the expression of eNOS,leading to accelerating AS.HSP22 overexpression decreases the expression of NF-κB and ICAM-1 and increases the expression of eNOS,thus attenuating AS development. HSP22 gene deletion partially limits the role of Ator in the expression of NF-κB,ICAM-1 and eNOS.HSP22 overexpression amplifies the reduced expression of ICAM-1 by the intervention with Ator,and further attenuates AS development.

Acyl CoA synthetase 5 (ACSL5) ablation in mice increases energy expenditure and insulin sensitivity and delays fat absorption.

OBJECTIVE: The family of acyl-CoA synthetase enzymes (ACSL) activates fatty acids within cells to generate long chain fatty acyl CoA (FACoA). The differing metabolic fates of FACoAs such as incorporation into neutral lipids, phospholipids, and oxidation pathways are differentially regulated by the ACSL isoforms. In vitro studies have suggested a role for ACSL5 in triglyceride synthesis; however, we have limited understanding of the in vivo actions of this ACSL isoform. METHODS: To elucidate the in vivo actions of ACSL5 we generated a line of mice in which ACSL5 expression was ablated in all tissues (ACSL5 (-/-) ). RESULTS: Ablation of ACSL5 reduced ACSL activity by ∼80% in jejunal mucosa, ∼50% in liver, and ∼37% in brown adipose tissue lysates. Body composition studies revealed that ACSL5 (-/-) , as compared to control ACSL5 (loxP/loxP) , mice had significantly reduced fat mass and adipose fat pad weights. Indirect calorimetry studies demonstrated that ACSL5 (-/-) had increased metabolic rates, and in the dark phase, increased respiratory quotient. In ACSL5 (-/-) mice, fasting glucose and serum triglyceride were reduced; and insulin sensitivity was improved during an insulin tolerance test. Both hepatic mRNA (∼16-fold) and serum levels of fibroblast growth factor 21 (FGF21) (∼13-fold) were increased in ACSL5 (-/-) as compared to ACSL5 (loxP/loxP) . Consistent with increased FGF21 serum levels, uncoupling protein-1 gene (Ucp1) and PPAR-gamma coactivator 1-alpha gene (Pgc1α) transcript levels were increased in gonadal adipose tissue. To further evaluate ACSL5 function in intestine, mice were gavaged with an olive oil bolus; and the rate of triglyceride appearance in serum was found to be delayed in ACSL5 (-/-) mice as compared to control mice. CONCLUSIONS: In summary, ACSL5 (-/-) mice have increased hepatic and serum FGF21 levels, reduced adiposity, improved insulin sensitivity, increased energy expenditure and delayed triglyceride absorption. These studies suggest that ACSL5 is an important regulator of whole-body energy metabolism and ablation of ACSL5 may antagonize the development of obesity and insulin resistance.

Effects of phosphatidylinositol-3 kinase/protein kinase b/bone morphogenetic protein-15 pathway on the follicular development in the mammalian ovary / 中国医学科学院学报

In mammals, ovarian follicle is made of an oocyte with its surrounding granulosa cells and theca cells. Follicular growth and development is a highly coordinated programmable process, which guarantees the normal oocyte maturation and makes it having the fertilizing capacity. The paracrine and autocrine between oocytes and granulosa cells are essential for the follicular development to provide a suitable microenvironment. Phosphatidylinositol-3 kinase /protein kinase B is one of these important regulatory signaling pathways during this developmental process, and bone morphogenetic protein-15 an oocyte-specific secreted signal molecule, which regulates the follicular development by paracrine in the mammalian ovary. The present article overviewed the role of phosphatidylinositol-3 kinase / protein kinase B signaling during the follicular development based on our previous investigation about protein kinase B /forkhead transcription factor forkhead family of transcription factors -3a, and then focused on the regulatory effects of bone morphogenetic protein-15, as a downstream signal molecule of phosphatidylinositol-3 kinase / forkhead family of transcription factors -3a pathway, on ovarian follicular development, which helped to further understand the molecular mechanism regulating the follicular development and to treat ovarian diseases like infertility.

The role of lipid droplets in metabolic disease in rodents and humans.

Lipid droplets (LDs) are intracellular organelles that store neutral lipids within cells. Over the last two decades there has been a dramatic growth in our understanding of LD biology and, in parallel, our understanding of the role of LDs in health and disease. In its simplest form, the LD regulates the storage and hydrolysis of neutral lipids, including triacylglycerol and/or cholesterol esters. It is becoming increasingly evident that alterations in the regulation of LD physiology and metabolism influence the risk of developing metabolic diseases such as diabetes. In this review we provide an update on the role of LD-associated proteins and LDs in metabolic disease.

Interferon regulatory factors are transcriptional regulators of adipogenesis.

We have sought to identify transcriptional pathways in adipogenesis using an integrated experimental and computational approach. Here, we employ high-throughput DNase hypersensitivity analysis to find regions of altered chromatin structure surrounding key adipocyte genes. Regions that display differentiation-dependent changes in hypersensitivity were used to predict binding sites for proteins involved in adipogenesis. A high-scoring example was a binding motif for interferon regulatory factor (IRF) family members. Expression of all nine mammalian IRF mRNAs is regulated during adipogenesis, and several bind to the identified motifs in a differentiation-dependent manner. Furthermore, several IRF proteins repress differentiation. This analysis suggests an important role for IRF proteins in adipocyte biology and demonstrates the utility of this approach in identifying cis- and trans-acting factors not previously suspected to participate in adipogenesis.

The protection of heme oxygenase-1 from acute cardiocyte injury in rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the protection of Heme oxygenase-1 (HO-1) from lipopolysaccharide (LPS)-induced cardiocyte injury and its mechanism.</p><p><b>METHODS</b>Cardiocyte was isolated from SD neonate rat and cultured in vitro, and was divided into control group (normal culture), LPS group (with stimulation of 30 micromoL/L LPS for 1 hour), LPS + Hemin group (with same treatment to LPS group after stimulation of 5 micromoL/L Hemin for 1 hour), and LPS + ZnPP group (with same treatment to LPS group after stimulation of 3 micromoL/L ZnPP for 1 hour). The level of lactic-dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) were measured by thio-barbituric acid and xanthine oxidase techniques. The cell heart rhythm, survival rate and apoptosis rate were examined. The expressions of nuclear factor kappaB (NF-kappaB), HO-1 and tumor necrosis factor-alpha (TNF-alpha) were measured with Western blotting. The HO-1 mRNA was examined by RT-PCR.</p><p><b>RESULTS</b>The level of LDH and MDA in LPS, LPS + Hemin, and LPS + ZnPP groups were (113 +/- 15), (79 +/- 13), (154 +/- 22) U/L, and (1.88 +/- 0.36), (1.16 +/- 0.32), (2.84 +/- 0.44) mmoL/L respectively, which were all obviously higher than those in control group [(69 +/- 10) U/L, (0.87 +/- 0.25) mmol/L, P < 0.05]. The level of SOD in LPS, PS + Hemin, and LPS + ZnPP groups (17.8 +/- 1.8, 22.5 +/- 2.4, 13.4 +/- 1.5 U/mL, respectively) was all obviously lower than that in control group (24.3 +/- 3.6 U/mL, P < 0.05). The apoptosis rate and heart rhythm were obviously higher and survival rate significantly lower in LPS, LPS + Hemin, and LPS + ZnPP groups than those in control group (P < 0.05). The level of HO-1mRNA in LPS, LPS + Hemin, and LPS + ZnPP groups was higher than that in control group (P < 0.01), among which LPS + Hemin group was the highest. The level of HO-1, TNF-alpha and NF-kappaB in LPS, LPS + Hemin, and LPS + ZnPP groups was higher than those in control group (P < 0.05), among which the level of HO-1 protein in LPS + Hemin group was the highest, the level of TNF-alpha and NF-kappaB in LPS + ZnPP group was highest.</p><p><b>CONCLUSION</b>LPS can induce cardiocyte injury, which can be inhibited through the anti-inflammatory, anti-oxidant, and anti-apoptosis functions by HO-1.</p>

The adipokine lipocalin 2 is regulated by obesity and promotes insulin resistance.

OBJECTIVE: We identified lipocalin 2 (Lcn2) as a gene induced by dexamethasone and tumor necrosis factor-alpha in cultured adipocytes. The purpose of this study was to determine how expression of Lcn2 is regulated in fat cells and to ascertain whether Lcn2 could be involved in metabolic dysregulation associated with obesity. RESEARCH DESIGN AND METHODS: We examined Lcn2 expression in murine tissues and in 3T3-L1 adipocytes in the presence and absence of various stimuli. We used quantitative Western blotting to observe Lcn2 serum levels in lean and obese mouse models. To assess effects on insulin action, we used retroviral delivery of short hairpin RNA to reduce Lcn2 levels in 3T3-L1 adipocytes. RESULTS: Lcn2 is highly expressed by fat cells in vivo and in vitro. Expression of Lcn2 is elevated by agents that promote insulin resistance and is reduced by thiazolidinediones. The expression of Lcn2 is induced during 3T3-L1 adipogenesis in a CCAAT/enhancer-binding protein-dependent manner. Lcn2 serum levels are elevated in multiple rodent models of obesity, and forced reduction of Lcn2 in 3T3-L1 adipocytes improves insulin action. Exogenous Lcn2 promotes insulin resistance in cultured hepatocytes. CONCLUSIONS: Lcn2 is an adipokine with potential importance in insulin resistance associated with obesity.

MZF1 possesses a repressively regulatory function in ERCC1 expression.

ERCC1 is a critical gene within the nucleotide excision repair pathway. Overexpression of ERCC1 through promoter-mediating transcriptional regulation is associated with repair of cisplatin-induced DNA damage and clinical resistance to platinum-chemotherapy. Several transcriptional repressors and activators within the 5'-flanking region of the ERCC1 gene may be involved in the up-regulation of this gene. Minimal sequence within the promoter region required for ERCC1 transcription was analyzed by CAT assay and demonstrated that the region of -220 to -110 is essential to constitutive expression of ERCC1 gene in ovarian cancer cell line A2780/CP70. A more forward upstream region seems to be responsible for cisplatin-induced expression. Study of the functional cis-element in this region by electrophoretic mobility shift assay indicates that a MZF1-like site as well as an AP1-like site responded in a time-dependent manner to cisplatin stimulation with altered binding activities. EMSA with MZF1 ZN1-4 consensus oligonucleotides suggests that the MZF1 N-terminal domain of zinc finger cluster may bind to the MZF1-like site of the ERCC1 promoter region. MZF1 mRNA in A2780/CP70 cells decreased upon cisplatin exposure as analyzed by quantitative PCR, suggesting that MZF1 may mediate cisplatin-invoked gene expression in these cells. Overexpression of MZF1 repressed the ERCC1 promoter activity as determined in co-transfection assay, suggesting that MZF1 might be a repressor of ERCC1 transcription upon cisplatin exposure. In summary, our studies revealed a core promoter region and adjacent drug-responsible region within the ERCC1 promoter. The drug-responsible region contains cis-elements of activator, AP1 and repressor, MZF1. In response to cisplatin treatment, decreased MZF1 and increased AP1 binding activities appear to be the leading mechanism of up-regulation of ERCC1 expression. Our findings imply potential therapeutic strategies to antagonize drug resistant mechanisms in treatment of human ovarian cancer.

AVP (4-8) May Stimulate a G Protein-coupled Receptor in Rat Hippocampal Synaptosomal Membranes.

As a metabolite of arginine-vasopressin, AVP(4-8) has been shown to have potent memory-enhancing activity and to induce a series of physiological and biochemical events in rat brain. GTP-binding protein is known to be a revolving stage of transmembrane signal transduction to mediate physiochemical responses of neurotransmitters and neuromodulators. A specific binding site of AVP(4-8) in the rat hippocampal synaptic membranes was identified by radio-receptor assay and after binding to membranes, AVP(4-8) enhanced the binding of Guanosine -5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPgammaS), and this enhancement could be completely reversed by the antagonist of AVP(4-8), ZNC(C)PR. Based on the alone results, we suggest that AVP(4-8) exerts its function as neurotransmitter through a G-protein-coupled receptor on the synaptosomal membrane of rat hippocampus.

The Binding Sites of AVP(4-8) in Rat Brain Are Different from the Known Receptors.

No Abstract