Hepatic expression profiling shows involvement of PKC epsilon, DGK eta, Tnfaip, and Rho kinase in type 2 diabetic nephropathy rats

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

Beneficial Effects of a Curcumin Derivative and Transforming Growth Factor-β Receptor I Inhibitor Combination on Nonalcoholic Steatohepatitis

BACKGRUOUND

Curcumin 2005-8 (Cur5-8), a derivative of curcumin, improves fatty liver disease via AMP-activated protein kinase activation and autophagy regulation. EW-7197 (vactosertib) is a small molecule inhibitor of transforming growth factor β (TGF-β) receptor I and may scavenge reactive oxygen species and ameliorate fibrosis through the SMAD2/3 canonical pathway. This study aimed to determine whether co-administering these two drugs having different mechanisms is beneficial.

METHODS

Hepatocellular fibrosis was induced in mouse hepatocytes (alpha mouse liver 12 [AML12]) and human hepatic stellate cells (LX-2) using TGF-β (2 ng/mL). The cells were then treated with Cur5-8 (1 μM), EW-7197 (0.5 μM), or both. In animal experiments were also conducted during which, methionine-choline deficient diet, Cur5-8 (100 mg/kg), and EW-7197 (20 mg/kg) were administered orally to 8-week-old C57BL/6J mice for 6 weeks.

RESULTS

TGF-β-induced cell morphological changes were improved by EW-7197, and lipid accumulation was restored on the administration of EW-7197 in combination with Cur5-8. In a nonalcoholic steatohepatitis (NASH)-induced mouse model, 6 weeks of EW-7197 and Cur5-8 co-administration alleviated liver fibrosis and improved the nonalcoholic fatty liver disease (NAFLD) activity score.

CONCLUSION

Co-administering Cur5-8 and EW-7197 to NASH-induced mice and fibrotic hepatocytes reduced liver fibrosis and steatohepatitis while maintaining the advantages of both drugs. This is the first study to show the effect of the drug combination against NASH and NAFLD. Similar effects in other animal models will confirm its potential as a new therapeutic agent.

p-Coumaric acid attenuates high-fat diet-induced oxidative stress and nephropathy in diabetic rats

The prevalence of persistent hyperglycaemia during diabetes, impair antioxidant defence system and generate reactive oxygen species, which majorly contribute to its progression and associated complications. Phytochemicals were suggested to scavenge-free radicals and exert antioxidant effects required to improve insulin sensitivity and reduce the occurrence of diabetes-associated complications. We hypothesise that a phenolic phytochemical p-coumaric can reduce diabetes-induced oxidative stress and improve diabetes-associated nephropathy in rats. The aim of this study is to analyse the protective effects of p-coumaric acid against diabetes-induced oxidative stress and nephropathy in high-fat diet-induced diabetic rats. The oral feeding of p-coumaric acid (20 mg/kg for 12 weeks) was found to significantly decrease the elevated levels of blood glucose in high-fat diet-induced type 2 diabetic rats. p-Coumaric acid treatment also decreases the kidney weight whilst increasing the total body weight of diabetic rats. Furthermore whilst evaluation of the different renal functioning tests, p-coumaric acid significantly improves histopathological changes and the levels of urea, creatinine and uric acid in serum of diabetic rats, which was otherwise elevated under diabetic conditions. Our results also highlight that p-coumaric acid is an efficient compound with antioxidant properties and improves the diabetes-induced change in lipid peroxidation and activities of antioxidant enzymes: catalase, glutathione-S-transferase and superoxide dismutase. p-Coumaric acid thus possesses the potential to prevent diabetic nephropathy by reducing oxidative stress and can thus serve as a potential drug target for pharmaceutical companies.

Determining KLF14 tertiary structure and diagnostic significance in brain cancer progression

Expression analysis of new protein targets may play a crucial role in the early detection and diagnosis of brain tumor progression. The study aimed to investigate the possible relation of KLF14, TPD52, miR-124, and PKCε in the development and progression of brain cancer and space occupying lesion (SOL) of the brain. One hundred human blood samples comprising varying diagnostic groups (SOL brain, grade I, II, III, IV) were analyzed by real-time quantitative PCR to determine the expression level of KLF14, TPD52, miR-124, and PKCε. TPD52 and PKCε were upregulated in brain cancer by 2.5- and 1.6-fold, respectively, whereas, KLF14 and miR-124 were downregulated in brain cancer. In metastatic and high-grade brain cancer, TPD52 and PKCε expression were up-regulated and KLF14 and miR-124 expression were down-regulated. Further, these genes were found to be differentially expressed in the blood of patients with SOL. Upregulation of TPD52 and PKCε, however, reduced expression of KLF14 and miR-124 in SOL of the brain as compared to healthy controls. Expression analysis of TPD52, KLF14, miR-124, and PKCε provided useful information on the differences existing between the normal brain and SOL, in addition to gliomas; thus, might prove to be useful having diagnostic or prognostic value.

Synthesis and evaluation of new 1,2,4-oxadiazole based trans- acrylic acid derivatives as potential PPAR-alpha/gamma dual agonist

Diabetes is a ubiquitously a metabolic disorder and life-threatening disease. Peroxisome proliferator-activated receptors (PPARs) belong to the class of nuclear receptors which acts as transcription factors to regulate lipid and glucose metabolism. PPAR alpha/gamma dual agonists tend to corroborate the functions of both thiazolidinediones and fibrates and they hold substantial promise for ameliorating the type 2 diabetic treatments and providing potential therapeutic diabetic interventions. New 1,2,4-oxadiazole based trans- acrylic acid derivatives compounds possessing aryl/methylene linker in between pharmacophore head and lipophilic tail for dual PPAR-alpha/gamma agonists are studied. AutoDock Vina used for potential PPAR alpha/gamma dual agonists and 6 compounds 9a, 9g, 9 m, 9n, 9o, and 9r were identified comparable to PPAR gamma agonist Pioglitazone on the basis of their affinity scores and further their in-silico toxicity and in-silico ADME properties. The selected compounds showed better-calculated lipophilicity (iLogP) was found to be 0.92 to 3.19. Compound 9n and 9a were found to be most potent on both PPAR alpha and gamma receptors with EC₅₀ of 0.07 ± 0.0006 µM, 0.06 ± 0.0005 µM and 0.781 ± 0.008 µM, 3.29 µM ± 0.03 respectively as better to pioglitazone having EC₅₀ of 32.38 ± 0.2 and 38.03 ± 0.13 for both receptors. The in-vivo evaluation found to reduce the plasma glucose level and total cholesterol level significantly in diabetic rats compared to pioglitazone at 5 mg/kg/day dose for 7 days of treatment. Thus, trans- acrylic acid derivatives can be further developed as oral therapeutic agents for diabetic interventions as PPAR alpha/gamma dual agonists.

Tissue-Specific Approaches Reveal Diverse Metabolic Functions of Rho-Kinase 1

Rho-kinase 1 (ROCK1) has been implicated in diverse metabolic functions throughout the body, with promising evidence identifying ROCK1 as a therapeutic target in diabetes and obesity. Considering these metabolic roles, several pharmacological inhibitors have been developed to elucidate the mechanisms underlying ROCK1 function. Y27632 and fasudil are two common ROCK1 inhibitors; however, they have varying non-specific selectivity to inhibit other AGC kinase subfamily members and whole-body pharmacological approaches lack tissue-specific insight. As a result, interpretation of studies with these inhibitors is difficult, and alternative approaches are needed to elucidate ROCK1's tissue specific metabolic functions. Fortunately, recent technological advances utilizing molecular carriers or genetic manipulation have facilitated discovery of ROCK1's tissue-specific mechanisms of action. In this article, we review the tissue-specific roles of ROCK1 in the regulation of energy balance and substrate utilization. We highlight prominent metabolic roles in liver, adipose, and skeletal muscle, in which ROCK1 regulates energy expenditure, glucose uptake, and lipid metabolism via inhibition of AMPK2α and paradoxical modulation of insulin signaling. Compared to ROCK1's roles in peripheral tissues, we also describe contradictory functions of ROCK1 in the hypothalamus to increase energy expenditure and decrease food intake via leptin signaling. Furthermore, dysregulated ROCK1 activity in either of these tissues results in metabolic disease phenotypes. Overall, tissue-specific approaches have made great strides in deciphering the many critical metabolic functions of ROCK1 and, ultimately, may facilitate the development of novel treatments for metabolic disorders.

Spatial Systems Lipidomics Reveals Nonalcoholic Fatty Liver Disease Heterogeneity

Hepatocellular lipid accumulation characterizes nonalcoholic fatty liver disease (NAFLD). However, the types of lipids associated with disease progression are debated, as is the impact of their localization. Traditional lipidomics analysis using liver homogenates or plasma dilutes and averages lipid concentrations, and does not provide spatial information about lipid distribution. We aimed to characterize the distribution of specific lipid species related to NAFLD severity by performing label-free molecular analysis by mass spectrometry imaging (MSI). Fresh frozen liver biopsies from obese subjects undergoing bariatric surgery (n = 23) with various degrees of NAFLD were cryosectioned and analyzed by matrix-assisted laser desorption/ionization (MALDI)-MSI. Molecular identification was verified by tandem MS. Tissue sections were histopathologically stained, annotated according to the Kleiner classification, and coregistered with the MSI data set. Lipid pathway analysis was performed and linked to local proteome networks. Spatially resolved lipid profiles showed pronounced differences between nonsteatotic and steatotic tissues. Lipid identification and network analyses revealed phosphatidylinositols and arachidonic acid metabolism in nonsteatotic regions, whereas low–density lipoprotein (LDL) and very low–density lipoprotein (VLDL) metabolism was associated with steatotic tissue. Supervised and unsupervised discriminant analysis using lipid based classifiers outperformed simulated analysis of liver tissue homogenates in predicting steatosis severity. We conclude that lipid composition of steatotic and nonsteatotic tissue is highly distinct, implying that spatial context is important for understanding the mechanisms of lipid accumulation in NAFLD. MSI combined with principal component–linear discriminant analysis linking lipid and protein pathways represents a novel tool enabling detailed, comprehensive studies of the heterogeneity of NAFLD.

miR-17-92 ameliorates renal ischemia reperfusion injury

There is limited information on the role of miR-17-92 in renal tubular pathophysiology. Therefore, the present study was performed to determine whether miR-17-92 plays a role in ischemia-reperfusion injury (IRI)-induced acute kidney injury. We originally demonstrated that miR-17-92 is up-regulated following IRI in vivo. To explore the roles of miR-17-92 in the IRI process, we first generated a renal proximal tubule-specific miR-17-92 deletion (PT-miR-17-92^-/-) knockout mouse model with Cre driven by the Kap promoter. We found that PT-deficient miR-17-92 mice had more severe renal dysfunction and renal structures than their littermates. Compared with sham-operated mice, both wide-type (WT) mice and PT-miR-17-92^-/- mice showed increased serum levels of creatinine and urea. However, the levels of serum urea and creatinine in PT-miR-17-92^-/- mice after the IRI operation were significantly higher than the levels in WT mice. In addition, PT-miR-17-92^-/- mice showed higher levels of serum potassium and phosphonium after the IRI operation. Histological analysis revealed that PT-miR-17-92^-/- mice had substantial histopathologic changes, such as tubular dilation and tubular necrosis. Overexpression of miR-17-92 could partially reverse the side-effects of IRI on the proximal tubules in vivo. Furthermore, we employed a quantitative proteomic strategy and identified 16 proteins as potential targets of miR-17-92. Taken together, our findings suggested that miR-17-92 may ameliorates IRI-induced acute kidney injury. Our results indicate that pharmacologic modulation of these miRNAs may have therapeutic potential for acute kidney injury.

Metformin ameliorates podocyte damage by restoring renal tissue nephrin expression in type 2 diabetic rats

BACKGROUND

Previous studies found that metformin provided some renoprotection for diabetic renal damage. In the present study, we evaluated the effects of different doses of metformin on the expression of renal tissue nephrin in type 2 diabetes mellitus (T2DM) model rats and the possible mechanism underlying its protective effect in kidney podocytes.

METHODS

A high-fat diet combined with a low dose of streptozotocin was used to induce T2DM model rats. Diabetic rats were treated with 150, 300, or 500 mg/kg metformin for 8 weeks. At the end of the study, urine and blood samples were collected for measurement of different indices. Light microscopy and transmission electron microscopy were used to identify morphological changes. Renal expression of nephrin protein was assayed by immunohistochemical staining, whereas real-time polymerase chain reaction was used to detect renal nephrin (Nphs1) mRNA expression.

RESULTS

Metformin treatment of T2DM rats produced dose-dependent significant reductions in urinary albumin and nephrin concentrations, glomerular basement membrane thickness (GBMT), and the foot process fusion rate (FPFR) compared with control T2DM model rats, whereas renal expression of nephrin protein and Nphs1 mRNA was dose-dependently increased by metformin treatment.

CONCLUSION

Metformin protects kidney podocytes in T2DM model rats by dose-dependently adjusting renal nephrin expression.

Association Study of Reported Significant Loci at 5q35.3, 7p14.3, 13q14.1 and 16p12.3 with Urolithiasis in Chinese Han Ethnicity

In this study, we aimed to validate the association of 8 reported significant loci at 5q35.3, 7p14.3, 13q14.1 and 16p12.3 with urolithiasis in Chinese Han population. We performed case-control association analysis using 624 patients with nephrolithiasis and 1008 control subjects. We selected single-nucleotide polymorphism (SNPs) including rs12654812 and rs11746443 from 5q32.3; rs12669187 and rs1000597 from 7q14.3; rs7981733, rs4142110 and rs17646069 from 13q14.1 and rs4293393 from 16p12.3 which were previously reported to be associated with nephrolithiasis. We found none of these eight reported SNPs were significant associated with urolithiasis risk in Chinese Han population, which suggested that differences could exist in the mechanisms of calcium urolithiasis between Chinese and Japanese Ethnics. The A allele of rs12669187 was significantly correlated with increased level of serum magnesium. The C allele of rs1000597 was associated with higher levels of serum creatinine, uric acid, calcium and lower urine pH level. The T allele of rs4142110 was correlated with higher levels of serum magnesium, phosphorus, and lower AKP level. The G alleles of rs4293393 was associated with higher serum CO₂ level. The risk alleles of these SNPs were proved to be associated with the electrolytes metabolism that may result in the formation of urolithiasis.

Tangzhiqing Granules Alleviate Podocyte Epithelial-Mesenchymal Transition in Kidney of Diabetic Rats

This study discussed the effect of Tangzhiqing granules on podocyte epithelial-mesenchymal transition in kidney of diabetic rats. The diabetic rats were divided randomly into five groups: DM group treated with vehicle, Tangzhiqing granules low-dose treatment group, Tangzhiqing granules middle-dose treatment group, and Tangzhiqing granules high-dose treatment group. Eight Wistar rats used as control group were given saline solution. The intervention was all intragastric administration for 8 weeks. At the end of the 8 weeks, biochemical parameters and kidney weight/body weight ratio were measured. The kidney tissues were observed under light microscope and transmission electron microscopy. To search for the underlying mechanism, we examined the epithelial-to-mesenchymal transition (EMT) related molecular markers and TGF-β/smad signaling pathway key proteins expression. The results showed that Tangzhiqing granules relieved the structural damage and functional changes of diabetic kidneys. Kidney podocyte EMT related molecular markers nephrin and CD2AP expression were increased, when desmin and α-SMA levels were decreased by Tangzhiqing granules in diabetic rats. Further TGF-β/smad signaling pathway key proteins TGF-β1 and p-smad2/3 levels were decreased in diabetic rats after treatment with Tangzhiqing granules. These findings suggest that Tangzhiqing granules may protect the podocytes of diabetic nephropathy rats via alleviating podocyte EMT and likely activating TGFβ/smad signaling pathway.

Saxagliptin Induces β-Cell Proliferation through Increasing Stromal Cell-Derived Factor-1α In Vivo and In Vitro

Dipeptidyl peptidase-4 inhibitors, such as saxagliptin, have been reported to have beneficial effects on β-cell function, but the specific underlying mechanism remains unclear. Stromal cell-derived factor-1α (SDF-1α), a chemokine produced in multiple organs, has been considered as a crucial regulator in promoting β-cell survival. Here, we speculate that SDF-1α might mediate the effect of saxagliptin on improving β-cell function. After 12-week saxagliptin treatment in high-fat diet/streptozotocin-induced diabetic rats, significant improvement in pancreas insulin secretion capacity evaluated by hyperglycemia clamp and increased β-cell to α-cell areas ratio were observed. Saxagliptin significantly induced β-cell proliferation and upregulated the expression of proliferation-related factors including c-myc and cyclind D1 determined with western blotting from the isolated islets. The expression/activity of DPP-4 was significantly reduced and paralleled with the restoration of SDF-1α levels in the saxagliptin-treated diabetic rats, subsequently the key WNT-signaling regulators, β-catenin, and AKT were activated. However, the effect of saxagliptin inducing β-cell proliferation was attenuated when we silenced the SDF-1α receptor (CXCR4) with RNAi in INS cell lines. Collectively, our data indicate that SDF-1α mediates the protective effect of saxagliptin on β-cell proliferation, suggesting that DPP-4 inhibitors have the potential role on delaying β-cell failure and SDF-1α could be a therapeutic target of β-cell regeneration.

Metformin Ameliorates Podocyte Damage by Restoring Renal Tissue Podocalyxin Expression in Type 2 Diabetic Rats

Podocalyxin (PCX) is a signature molecule of the glomerular podocyte and of maintaining integrity of filtration function of glomerulus. The aim of this study was to observe the effect of different doses of metformin on renal tissue PCX expression in type 2 diabetic rats and clarify its protection on glomerular podocytes. Type 2 diabetic Sprague-Dawley (SD) rats in which diabetes was induced by high-fat diet/streptozotocin (HFD-STZ) were treated with different doses of metformin (150, 300, and 500 mg/kg per day, resp.) for 8 weeks. Various biochemical parameters, kidney histopathology, and renal tissue PCX expression levels were examined. In type 2 diabetic rats, severe hyperglycemia and hyperlipidemia were developed. Urinary albumin and PCX were markedly increased. Diabetes induced significant alterations in renal glomerular structure. In addition, protein and mRNA expression of renal tissue PCX were highly decreased. However, treatment of rats with different doses of metformin restored all these changes to a varying degree. These results suggested that metformin can ameliorate glomerular podocyte damage in type 2 diabetic rats, which may be partly associated with its role in restoring PCX expression and inhibiting urinary excretion of PCX with dose dependence.

A comparative study of the toxicological aspects of vanadium pentoxide and vanadium oxide nanoparticles

Indiscriminate use of vanadium oxide nanoparticles (NPs) in steel industries and their release during combustion of fossil fuels makes it essential to study their toxic potential. Herein, we assessed the toxicological effects of two types of in-house synthesized vanadium oxide NPs in Wistar rats exposed to NPs through inhalation route. V2O5 and VO2 NPs exhibited rod and spherical symmetry, respectively with a mean diameter of 50±20 and 30±10 nm. Assessment of bronchoalveolar lavage fluid parameters demonstrated that VO2 NP-exposed animals had higher levels of lactate dehydrogenase, gamma-glutamyl transpeptidase and alkaline phosphatase as compared to V2O5 NP-exposed animals. The levels of oxidative stress markers malondialdehyde and reduced glutathione also indicated higher toxic potential of VO2 NPs. Moreover, after 7-day recovery, the levels of the above parameters were closer to normal levels only in V2O5-exposed animals. Interestingly, histopathological and immune-histopathology analysis (TNF-α) of lung tissue showed higher damage and inflammatory response in VO2 NP-exposed animals, which persisted even after 7 days of recovery period. Surprisingly, the carcinogenic potential of vanadium oxide NPs came into light which was indicated by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay as well as the decreased levels of p53 and Bax, in lung tissue of NP-exposed animals. Notably, the physiochemical characterization of NPs, especially the shape and the size, play a central role in shaping the toxicity of these NPs and thus should be extensively evaluated for outlining the regulatory guidelines.

17-β Oestradiol prevents cardiovascular dysfunction in post-menopausal metabolic syndrome by affecting SIRT1/AMPK/H3 acetylation

BACKGROUND AND PURPOSE

Oestrogen therapy is known to induce cardioprotection in post-menopausal metabolic syndrome (PMS). Hence, we investigated the effect of 17-β oestradiol (E2) on functional responses to angiotensin II and cardiovascular dysfunction in a rat model of PMS.

EXPERIMENTAL APPROACH

PMS was induced in ovariectomized rats by feeding a high-fat diet for 10 weeks. Isometric tension responses of aortic rings to angiotensin II were recorded using an isometric force transducer. TUNEL assay and immunoblotting was performed to assess apoptosis and protein expression respectively in PMS.

KEY RESULTS

Endothelial dysfunction in PMS was characterized by enhanced angiotensin II-induced contractile responses and impaired endothelial dependent vasodilatation. This was associated with an increased protein expression of AT1 receptors in the aorta and heart in PMS. PMS induced cardiac apoptosis by activating Bax and PARP protein expression. These changes were associated with a down-regulation in the expression of silent information regulation 2 homologue (SIRT1)/P-AMP-activated PK (AMPK) and increased H3 acetylation in aorta and heart. E2 partially suppressed angiotensin II-induced contractions, restored the protein expression of SIRT1/P-AMPK and suppressed H3 acetylation. The role of SIRT1/AMPK was further highlighted by administration of sirtinol and compound C (ex vivo), which enhanced angiotensin II contractile responses and ablated the protective effect of E2 on PMS.

CONCLUSION AND IMPLICATIONS

Our results provide novel mechanisms for PMS-induced cardiovascular dysfunction involving SIRT1/AMPK/ histone H3 acetylation, which was prevented by E2. The study suggests that therapies targeting SIRT1/AMPK/epigenetic modifications may be beneficial in reducing the risk of cardiovascular disorders.

Estrogen is a novel regulator of Tnfaip1 in mouse hippocampus

Tumor necrosis factor‑induced protein 1 (Tnfaip1), also known as B12, has been previously identified as a tumor necrosis factor-α (TNF-α)-inducible protein and is involved in the cytokinesis signaling pathway, DNA synthesis, innate immunity, cell apoptosis, Alzheimer's disease (AD) and type 2 diabetic nephropathy. However, little is known regarding the expression of Tnfaip1 in various tissues or its accurate role in these physiological functions. The focus of this study was on Tnfaip1 expression in different tissues, with a high expression in mouse hippocampus being identified. The age- and gender‑related expression of Tnfaip1 in hippocampus was also investigated. The distribution of Tnfaip1 was mapped using fluorescent immunostaining. Although immunoactivity was found in the CA1, CA3 and DG subregions of the hippocampus in E17.5 and P6 mice, strong staining was only detected in the CA3 subregion in adult mice. These data suggested that Tnfaip1 expression in hippocampus may be regulated by estrogen. Further study showed that the expression of Tnfaip1 in the hippocampus was significantly increased in ovariecto-mized mice compared to Sham mice. In cultured primary hippocampal cells, Tnfaip1 showed different expression levels in different treatments of estrogen or estrogen receptor antagonists. Additional experiments demonstrated the existence of a binding site of ERβ in the Tnfaip1 promoter region, and that ERβ was able to upregulate Tnfaip1 expression. Our study identified a new regulatory factor and a primary regulatory mechanism of Tnfaip1 expression in hippocampus. Since both hippocampus and estrogen are crucial in AD, the results also showed a potential association between Tnfaip1 and hippocampal-related diseases, such as AD, which may be affected by the estrogen level.

Epigenetic changes and alteration of Fbn1 and Col3A1 gene expression under hyperglycaemic and hyperinsulinaemic conditions

Little is known regarding the role of hyperglycaemia on histone H3 modifications and, in turn, altering the expression of genes during the development of diabetes-associated complications. In the present study, we have investigated the hyperinsulinaemia/hyperglycaemia-induced epigenetic changes and alteration of Fbn1 (fibrillin 1) and Col3A1 (collagen type III α1) gene expression. Insulin resistance and Type 2 diabetes in male Sprague-Dawley rats was developed by feeding rats an HFD (high-fat diet) and administering a low dose of STZ (streptozotocin). Hyperglycaemia induced deacetylation and dephosphorylation of histone H3 in the heart and kidneys of diabetic rats. Furthermore, mRNA expression of Fbn1 and Col3A1 increased in the kidneys and decreased in the heart under hyperglycaemic/hyperinsulinaemic conditions. Similar to mRNA expression, chromatin immunoprecipitation also showed an increase in the level of histone H3 acetylation of the Fbn1 gene, but not of the Col3A1 gene. Our present findings suggests that the change in expression of the Fbn1 gene is epigenetically regulated, but the expression of the Col3A1 gene may either be independent of epigenetic regulation or may involve other histone modifications. We provide the first evidence regarding the role of hyperglycaemia/hyperinsulinaemia in altering histone H3 modifications, which may result in the alteration of extracellular matrix gene expression.