Association between Free Thyroxine Levels and Diabetic Retinopathy in Euthyroid Patients with Type 2 Diabetes Mellitus.

Background: This study aimed to evaluate the association between thyroid parameters and diabetic retinopathy (DR) in euthyroid patients with type 2 diabetes mellitus (T2DM).Materials and Methods: In this cross-sectional study, a total of 911 euthyroid patients with T2DM (539 men and 372 women; mean age, 60.81 ± 12.93 years) were enrolled. Clinical factors were assessed and free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels were measured. DR was diagnosed using fundus fluorescein angiography.Results: Compared with patients without DR (n = 718), patients with DR (n = 193) exhibited lower FT3 (4.40 ± 0.58 vs. 4.50 ± 0.51 pmol/L; P = .019) and FT4 (14.86 ± 2.09 vs. 15.91 ± 2.18 pmol/L; P < .001) and higher TSH (1.86 [1.22, 2.66] vs. 1.58 [1.14, 2.34] µIU/mL; P = .015) levels. After adjustment for potential DR risk factors, patients in the highest tertile of plasma FT4 levels had a 0.332-fold likelihood of developing DR compared with those in the lowest tertile of plasma FT4 levels (Ptrend < 0.001). The prevalence of DR showed a significantly decreasing trend across the three tertiles based on FT4 levels (31.35%, 19.08% and 13.16%; Ptrend < 0.001). Similar results were obtained for the presence of proliferative DR.Conclusion: These findings suggest that low-normal FT4 levels are associated with the prevalence of DR in euthyroid patients with T2DM.

The arginine methyltransferase PRMT5 regulates CIITA-dependent MHC II transcription.

Class II major histocompatibility complex (MHC II) dependent antigen presentation serves as a key step in mammalian adaptive immunity and host defense. In antigen presenting cells (e.g., macrophages), MHC II transcription can be activated by interferon gamma (IFN-γ) and mediated by class II transactivator (CIITA). The underlying epigenetic mechanism, however, is not completely understood. Here we report that following IFN-γ stimulation, symmetrically dimethylated histone H3 arginine 2 (H3R2Me2s) accumulated on the MHC II promoter along with CIITA. IFN-γ augmented expression, nuclear translocation, and promoter binding of the protein arginine methyltransferase PRMT5 in macrophages. Over-expression of PRMT5 potentiated IFN-γ induced activation of MHC II transcription in an enzyme activity-dependent manner. In contrast, PRMT5 silencing or inhibition of PRMT5 activity by methylthioadenosine (MTA) suppressed MHC II transactivation by IFN-γ. CIITA interacted with and recruited PRMT5 to the MHC II promoter and mediated the synergy between PRMT5 and ASH2/WDR5 to activate MHC II transcription. PRMT5 expression was down-regulated in senescent and H2O2-treated macrophages rendering ineffectual induction of MHC II transcription by IFN-γ. Taken together, our data reveal a pathophysiologically relevant role for PRMT5 in MHC II transactivation in macrophages.

HIC1 epigenetically represses CIITA transcription in B lymphocytes.

Differentiation of B lymphocytes into isotope-specific plasma cells represents a hallmark event in adaptive immunity. During B cell maturation, expression of the class II transactivator (CIITA) gene is down-regulated although the underlying epigenetic mechanism is not completely defined. Here we report that hypermethylated in cancer 1 (HIC1) was up-regulated in differentiating B lymphocytes paralleling CIITA repression. Over-expression of HIC1 directly repressed endogenous CIITA transcription in B cells. Reporter assay and chromatin immunoprecipitation (ChIP) assay confirmed that HIC1 bound to the proximal CIITA type III promoter (-545/-113); mutation of a conserved HIC1 site within this region abrogated CIITA trans-repression. More important, depletion of HIC1 with small interfering RNA (siRNA) restored CIITA expression in differentiating B cells. Mechanistically, HIC1 preferentially interacted with and recruited DNMT1 and DNMT3b to the CIITA promoter to synergistically repress CIITA transcription. On the contrary, silencing of DNMT1/DNMT3b or inhibition of DNMT activity with 5-aza-dC attenuated CIITA trans-repression. Therefore, our data identify HIC1 as a novel factor involved in B cell differentiation acting as an epigenetic repressor of CIITA transcription.

Association Between Serum Zinc and Non-Alcoholic Fatty Liver Disease and Advanced Liver Fibrosis: NHANES 2011-2016.

Limited and inconclusive evidence exists regarding the correlation between serum zinc levels and non-alcoholic fatty liver disease (NAFLD) and advanced fibrosis. The objective of this cross-sectional study was to investigate the association between serum zinc concentration and both NAFLD and advanced liver fibrosis among the United States (US) adults. 3398 subjects from National Health and Nutrition Examination Survey (NHANES) 2011-2016 were included. Serum zinc concentration was measured by inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS). NAFLD was diagnosed with Hepatic Steatosis Index (HSI), and advanced fibrosis risk was assessed by NAFLD Fibrosis Score (NFS). Weighted logistic regression and restricted cubic splines (RCS) were used to examine the association between serum zinc concentration and NAFLD and advanced fibrosis. Linear trend tests were conducted by incorporating the median of serum zinc quartiles as a continuous variable in the models. We employed sensitivity analysis and subgroup analysis to enhance the robustness of our results. The results from the RCS regression revealed no evident nonlinear relationship between serum zinc concentration and the presence of NAFLD and advanced fibrosis (p-nonlinear > 0.05). Compared with those in the lowest quartile (Q1) of serum zinc concentrations, the odds ratios (95% confidence intervals) of NAFLD were 1.49 (0.89,2.49) in Q2, 0.99 (0.68,1.45) in Q3, and 2.00 (1.40,2.86) in Q4 (p-trend = 0.002). Similarly, the odds ratios (95% confidence intervals) for advanced fibrosis in Q2-4 compared to Q1 were 0.86 (0.50,1.47), 0.60 (0.26,1.39), and 0.41 (0.21,0.77), respectively (p-trend = 0.006). Subgroup analyses and sensitivity analyses reinforce the same conclusion. The investigation revealed a positive linear relationship between serum zinc concentrations and the probability of developing NAFLD. Conversely, an inverse correlation was observed between serum zinc concentrations and the incidence of advanced liver fibrosis among individuals diagnosed with NAFLD.

Matrix metallopeptidase 9 contributes to the beginning of plaque and is a potential biomarker for the early identification of atherosclerosis in asymptomatic patients with diabetes.

Aims: To determine the roles of matrix metallopeptidase-9 (MMP9) on human coronary artery smooth muscle cells (HCASMCs) in vitro, early beginning of atherosclerosis in vivo in diabetic mice, and drug naïve patients with diabetes. Methods: Active human MMP9 (act-hMMP9) was added to HCASMCs and the expressions of MCP-1, ICAM-1, and VCAM-1 were measured. Act-hMMP9 (n=16) or placebo (n=15) was administered to diabetic KK.Cg-Ay/J (KK) mice. Carotid artery inflammation and atherosclerosis measurements were made at 2 and 10 weeks after treatment. An observational study of newly diagnosed drug naïve patients with type 2 diabetes mellitus (T2DM n=234) and healthy matched controls (n=41) was performed and patients had ultrasound of carotid arteries and some had coronary computed tomography angiogram for the assessment of atherosclerosis. Serum MMP9 was measured and its correlation with carotid artery or coronary artery plaques was determined. Results: In vitro, act-hMMP9 increased gene and protein expressions of MCP-1, ICAM-1, VCAM-1, and enhanced macrophage adhesion. Exogenous act-hMMP9 increased inflammation and initiated atherosclerosis in KK mice at 2 and 10 weeks: increased vessel wall thickness, lipid accumulation, and Galectin-3+ macrophage infiltration into the carotid arteries. In newly diagnosed T2DM patients, serum MMP9 correlated with carotid artery plaque size with a possible threshold cutoff point. In addition, serum MMP9 correlated with number of mixed plaques and grade of lumen stenosis in coronary arteries of patients with drug naïve T2DM. Conclusion: MMP9 may contribute to the initiation of atherosclerosis and may be a potential biomarker for the early identification of atherosclerosis in patients with diabetes. Clinical trial registration: https://clinicaltrials.gov, identifier NCT04424706.

11ß-Hydroxysteroid dehydrogenase type 1 selective inhibitor BVT.2733 protects osteoblasts against endogenous glucocorticoid induced dysfunction.

Pharmacologic glucocorticoids (GCs) inhibit osteoblast function and induce osteoporosis. 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) may play a role in osteoporosis as it regulates GC action at a pre-receptor level by converting inactive GC to its active form. Further, 11ß-HSD1 was found increasingly expressed in bone with age. In spite of these observations, its function in senile osteoporosis remains uncertain. In this study we constructed a lentiviral vector overexpressing mouse 11ß-HSD1 and then MC3T3-E1 preosteoblast cells were infected by the negative control lentivirus and 11ß-HSD1-overexpressing lentivirus, respectively. The mRNA and protein levels of 11ß-HSD1 were significantly increased in MC3T3-E1 cells that were infected by 11ß-HSD1-overexpressing lentivirus compared to the cells infected by the negative control lentivirus. The osteogenic differentiation of MC3T3-E1 preosteoblast cells was dramatically suppressed by 11ß-HSD1 overexpression under the reductase substrate dehydrocorticosterone (DHC). The inhibition effect was similar to the inhibition of osteogenesis by over-dose GCs, including ALP activity, the ultimate calcium nodus formation as well as the expression of the osteogenic genes such as ALP, BSP, OPN and OCN. However, with addition of BVT.2733, a selective inhibitor of 11ß-HSD1, all of the above osteogenic repression effects by 11ß-HSD1 overexpression were reversed. Furthermore, a GC receptor antagonist RU486 also showed the similar effect, preventing inhibition of osteogenesis by 11ß-HSD1 overexpression. These results demonstrated that the specific 11ß-HSD1 inhibitor BVT.2733 can reverse the suppression effect towards osteogenic differentiation in 11ß-HSD1 overexpressed MC3T3-E1 cells. Inhibition of 11ß-HSD1 can be a new therapeutic strategy for senile osteoporosis.

SIRT1 links CIITA deacetylation to MHC II activation.

Antigen-dependent stimulation of T cells plays a critical role in adaptive immunity and host defense. Activation of major histocompatibility complex II (MHC II) molecules, dictated by Class II transactivator (CIITA), is considered a pivotal step in this process. The mechanism underlying differential regulation of CIITA activity by the post-translational modification machinery (PTM) and its implications are not clearly appreciated. Here, we report that SIRT1, a type III deacetylase, interacts with and deacetylates CIITA. SIRT1 activation augments MHC II transcription by shielding CIITA from proteasomal degradation and promoting nuclear accumulation and target binding of CIITA. In contrast, depletion of SIRT1 upregulates CIITA acetylation and attenuates its activity. Nicotinamide phosphoribosyltransferase (NAMPT) that synthesizes NAD(+) required for SIRT1 activation exerts similar effects on CIITA activity. Two different types of stress stimuli, hypobaric hypoxia and oxidized low-density lipoprotein (oxLDL), induce the acetylation of CIITA and suppress its activity by inhibiting the SIRT1 expression and activity. Thus, our data link SIRT1-mediated deacetylation of CIITA to MHC II transactivation in macrophages and highlight a novel strategy stress cues may employ to manipulate host adaptive immune system.

Upregulation of Neogenin-1 by a CREB1-BAF47 Complex in Vascular Endothelial Cells is Implicated in Atherogenesis.

Atherosclerosis is generally considered a human pathology of chronic inflammation, to which endothelial dysfunction plays an important role. Here we investigated the role of neogenin 1 (Neo-1) in oxidized low-density lipoprotein (oxLDL) induced endothelial dysfunction focusing on its transcriptional regulation. We report that Neo-1 expression was upregulated by oxLDL in both immortalized vascular endothelial cells and primary aortic endothelial cells. Neo-1 knockdown attenuated whereas Neo-1 over-expression enhanced oxLDL-induced leukocyte adhesion to endothelial cells. Neo-1 regulated endothelial-leukocyte interaction by modulating nuclear factor kappa B (NF-κB) activity to alter the expression of adhesion molecules. Neo-1 blockade with a blocking antibody ameliorated atherogenesis in Apoe -/- mice fed a Western diet. Ingenuity pathway analysis combined with validation assays confirmed that cAMP response element binding protein 1 (CREB1) and Brg1-associated factor 47 (BAF47) mediated oxLDL induced Neo-1 upregulation. CREB1 interacted with BAF47 and recruited BAF47 to the proximal Neo-1 promoter leading to Neo-1 trans-activation. In conclusion, our data delineate a novel transcriptional mechanism underlying Neo-1 activation in vascular endothelial cells that might contribute to endothelial dysfunction and atherosclerosis.

Thymosin beta-4 improves endothelial function and reparative potency of diabetic endothelial cells differentiated from patient induced pluripotent stem cells.

BACKGROUND: Prior studies show that signature phenotypes of diabetic human induced pluripotent stem cells derived endothelial cells (dia-hiPSC-ECs) are disrupted glycine homeostasis, increased senescence, impaired mitochondrial function and angiogenic potential as compared with healthy hiPSC-ECs. In the current study, we aimed to assess the role of thymosin ß-4 (Tb-4) on endothelial function using dia-hiPSC-ECs as disease model of endothelial dysfunction. METHODS AND RESULTS: Using dia-hiPSC-ECs as models of endothelial dysfunction, we determined the effect of Tb-4 on cell proliferation, senescence, cyto-protection, protein expression of intercellular adhesion molecule-1 (ICAM-1), secretion of endothelin-1 and MMP-1, mitochondrial membrane potential, and cyto-protection in vitro and angiogenic potential for treatment of ischemic limb disease in a mouse model of type 2 diabetes mellitus (T2DM) in vivo. We found that 600 ng/mL Tb4 significantly up-regulated AKT activity and Bcl-XL protein expression, enhanced dia-hiPSC-EC viability and proliferation, limited senescence, reduced endothelin-1 and MMP-1 secretion, and improved reparative potency of dia-hiPSC-ECs for treatment of ischemic limb disease in mice with T2DM. However, Tb4 had no effect on improving mitochondrial membrane potential and glycine homeostasis and reducing intercellular adhesion molecule-1 protein expression in dia-hiPSC-ECs. CONCLUSIONS: Tb-4 improves endothelial dysfunction through enhancing hiPSC-EC viability, reducing senescence and endothelin-1 production, and improves angiogenic potency in diabetes.

RFXB and its splice variant RFXBSV mediate the antagonism between IFNgamma and TGFbeta on COL1A2 transcription in vascular smooth muscle cells.

Cytokines secreted by infiltrating immune cells during atherogenesis modulate vascular remodeling. One exemplary event is the antagonism between transformed growth factor (TGF-beta) and interferon gamma (IFN-gamma) on the transcriptional control of type I collagen gene (COL1A2). Previously we have reported that IFN-gamma up-regulates regulatory factor for X-box B (RFXB) to repress collagen transcription while down-regulates the expression of RFXBSV, a splice variant of RFXB that blocks collagen repression in fibroblasts. Here we demonstrate that TGF-beta abrogated COL1A2 repression by IFN-gamma through altering the relative expression of RFXB and RFXBSV. Unlike RFXB, RFXBSV did not bind to the collagen promoter and competed with RFXB for the co-repressor histone deacetylase 2 (HDAC2), limiting HDAC2 recruitment to the collagen transcription start site as evidenced by chromatin immunoprecipitation assays. Over-expression of RFXB by lentiviral infection in HASMCs enhanced HDAC2 enlistment, promoted histone deacetylation surrounding the collagen site by IFN-gamma, and blocked the TGF-beta antagonism, a pattern reversed by RFXBSV infection. On the contrary, silencing of RFXB, but not both RFXB and RFXBSV, expression promoted the TGF-beta antagonism. Thus, we have identified a novel mechanism whereby TGF-beta antagonizes the IFN-gamma repression of collagen transcription in HASMCs and as such provided new insights into antiatherogenic strategies.

Needle-free jet injection of insulin glargine improves glycemic control in patients with type 2 diabetes mellitus: a study based on the flash glucose monitoring system.

Background: To investigate the effects of insulin glargine injection given with a QS-P jet injector on the glucose profile using a professional mode flash glucose monitoring (FGM) system in patients with type 2 diabetes mellitus (T2DM).Research design and methods: In this randomized, controlled, cross-sectional study, 66 patients with T2DM who received insulin glargine (12-18 IU/day) injection were enrolled. The patients were randomly divided into group A (jet injector before insulin pen) and group B (insulin pen before jet injector). Each subject injected insulin daily before breakfast. We analyzed the changes in the glucose profile using a professional mode FGM system.Results: Treatment with a jet injector led to significantly lower 24-h mean glucose, maximum blood glucose, area under the curve (AUC) > 10.0 mmol/L, time above range and increased AUC < 3.9 mmol/L and time below range than those when using an insulin pen. There was no difference in glycemic variability between the two groups. We observed that patients using a jet injector had significantly lower mean glucose between 12:00 to 22:00.Conclusions: Needle-free jet injection of insulin glargine was more effective than use of an insulin pen for good glycemic control in patients with T2DM.Clinical trial registration: www.clinicaltrials.gov identifier is NCT04093284.

Diabetic Endothelial Cells Differentiated From Patient iPSCs Show Dysregulated Glycine Homeostasis and Senescence Associated Phenotypes.

Induced pluripotent stem cells derived cells (iPSCs) not only can be used for personalized cell transfer therapy, but also can be used for modeling diseases for drug screening and discovery in vitro. Although prior studies have characterized the function of rodent iPSCs derived endothelial cells (ECs) in diabetes or metabolic syndrome, feature phenotypes are largely unknown in hiPSC-ECs from patients with diabetes. Here, we used hiPSC lines from patients with type 2 diabetes mellitus (T2DM) and differentiated them into ECs (dia-hiPSC-ECs). We found that dia-hiPSC-ECs had disrupted glycine homeostasis, increased senescence, and impaired mitochondrial function and angiogenic potential as compared with healthy hiPSC-ECs. These signature phenotypes will be helpful to establish dia-hiPSC-ECs as models of endothelial dysfunction for understanding molecular mechanisms of disease and for identifying and testing new targets for the treatment of endothelial dysfunction in diabetes.

Corrigendum: BRG1 Stimulates Endothelial Derived Alarmin MRP8 to Promote Macrophage Infiltration in an Animal Model of Cardiac Hypertrophy.

[This corrects the article DOI: 10.3389/fcell.2020.00569.].

BRG1 Stimulates Endothelial Derived Alarmin MRP8 to Promote Macrophage Infiltration in an Animal Model of Cardiac Hypertrophy.

Endothelial cell derived angiocrine factors contribute to the disruption of homeostasis and the pathogenesis of cardiovascular diseases in response to stress stimuli. In the present study we investigated the role of BRG1, a key component of the chromatin remodeling complex, in the regulation of angiocrine signaling. We report that angiotensin II (Ang II) induced pathological cardiac hypertrophy was attenuated in mice with endothelial-specific ablation of BRG1 (ecKO) compared to the control mice (WT). Mitigation of cardiac hypertrophy as a result of BRG1 deficiency was accompanied by decreased macrophage homing to the hearts. This could be explained by the observation that the ecKO mice exhibited down-regulation of myeloid-related protein 8 (MRP8), a well-established chemokine for macrophages, in vascular endothelial cells compared to the WT mice. Further analysis revealed that BRG1 mediated the activation of MRP8 expression by Ang II treatment in endothelial cells to promote macrophage migration. BRG1 was recruited to the MRP8 promoter by interacting with hypoxia-inducible factor 1 (HIF-1α). Reciprocally, BRG1 facilitated the binding of HIF-1α to the MRP8 promoter by sequentially recruiting histone acetyltransferase p300 and histone demethylase KDM3A. Depletion of either p300 or KDM3A repressed the induction of MRP8 expression by Ang II and ameliorated macrophage migration. In conclusion, our data delineate a novel epigenetic pathway whereby Ang II stimulates MRP8 production and macrophage homing to promote cardiac hypertrophy.

The Accuracy and Precision of the Continuously Stored Data from Flash Glucose Monitoring System in Type 2 Diabetes Patients during Standard Meal Tolerance Test.

BACKGROUND: The purpose of this study was to investigate the accuracy of the continuously stored data from the Abbott FreeStyle Libre flash glucose monitoring (FGM) system in Chinese diabetes patients during standard meal tests when glucose concentrations were rapidly changing. Subjects and Methods. Interstitial glucose levels were monitored for 14 days in 26 insulin-treated patients with type 2 diabetes using the FGM system. Standard meal tests were conducted to induce large glucose swings. Venous blood glucose (VBG) was tested at 0, 30, 60, and 120 min after standard meal tests in one middle day of the first and second weeks, respectively. The corresponding sensor glucose values were obtained from interpolating continuously stored data points. Assessment of accuracy was according to recent consensus recommendations with median absolute relative difference (MARD) and Clarke and Parkes error grid analysis (CEG and PEG). RESULTS: Among 208 paired sensor-reference values, 100% were falling within zones A and B of the Clarke and Parkes error grid analysis. The overall MARD was 10.7% (SD, 7.8%). Weighted least squares regression analysis resulted in high agreement between the FGM sensor glucose and VBG readings. The overall MTT results showed that FGM was lower than actual VBG, with MAD of 22.1 mg/dL (1.2 mmol/L). At VBG rates of change of -1 to 0, 0 to 1, 1 to 2, and 2 to 3 mg/dl/min, MARD results were 11.4% (SD, 8.7%), 9.4% (SD, 6.5%), 9.9% (SD, 7.5%), and 9.5% (SD, 7.7%). At rapidly changing VBG concentrations (>3 mg/dl/min), MARD increased to 19.0%, which was significantly higher than slow changing BG groups. CONCLUSIONS: Continuously stored interstitial glucose measurements with the FGM system were found to be acceptable to evaluate VBG in terms of clinical decision during standard meal tests. The continuously stored data from the FGM system appeared to underestimate venous glucose and performed less well during rapid glucose changes.

Effect of Dapagliflozin on Glycemic Variability in Patients with Type 2 Diabetes under Insulin Glargine Combined with Other Oral Hypoglycemic Drugs.

AIM: To evaluate the effect of an inhibitor of sodium-glucose cotransporter 2 (SGLT-2 inhibitor, dapagliflozin) on glycemic variability in type 2 diabetes mellitus (T2D) under insulin glargine combined with oral hypoglycemic drugs, using a continuous glucose monitoring system (CGMS). METHODS: This prospective, self-controlled, single-center clinical trial recruited 36 patients with T2D under combined insulin glargine and oral hypoglycemic drugs. General clinical data were collected. Fasting blood glucose (FBG), postprandial blood glucose (PBG), glycosylated hemoglobin (HbA1c), and C-peptide levels were assessed before and four weeks of dapagliflozin (10 mg per day) treatment. Blood glucose was monitored for 72 hours before and after treatment using CGMS. RESULTS: After treatment with dapagliflozin, FBG decreased from 6.74 ± 1.78 to 5.95 ± 1.13 mmol/L (p < 0.05); PBG decreased from 13.04 ± 2.99 to 10.92 ± 3.26 mmol/L (p < 0.05); HbA1c decreased from 7.37 ± 0.96% to 6.94 ± 0.80%. The proportion of patients with HbA1c < 7% increased from 27.8% to 58.3%, and the proportion of patients with HbA1c < 7% and without level 2 hypoglycemia increased from 27.8% to 55.6% (p < 0.05). CGMS data showed reduction of the 24 h MBG, MAGE, time-above-range (TAR, >10 mmol/L), high blood glucose index (HBGI), glucose management indicator (GMI), and incremental area under the curve of the glucose level more than 10 mmol/L (AUC > 10) and an increase of time-in-range (TIR, 3.9-10 mmol/L) with treatment. Homeostasis model assessment for pancreatic beta-cell function (HOMA-beta) increased significantly with treatment (p < 0.05), and fewer insulin doses were required after the treatment, without increasing in hypoglycemia and urinary tract infection. Further, a stratified analysis showed that patients with higher pretreatment HbA1c and waist-to-hip ratio (WHR) had greater improvement in glycemic control. CONCLUSION: Dapagliflozin may reduce blood glucose levels, ameliorate glycemic variability, and improve pancreatic beta-cell function in patients with T2D under insulin glargine combined with other oral hypoglycemic drugs, especially in those with poor glucose control and abdominal obesity.

HDAC2 deacetylates class II transactivator and suppresses its activity in macrophages and smooth muscle cells.

Macrophage-triggered chronic inflammation and smooth muscle cell-initiated vascular remodeling are two major pathophysiologic events during atherogenesis. Major histocompatibility class II (MHC II) transactivator (CIITA) is a key mediator of these processes through transcriptional regulation of interferon gamma (IFN-gamma) induced MHC II activation and type I collagen repression. Transcriptional activity of CIITA is regulated by multiple post-translational modifications. Here we report that CIITA and histone deacetylase 2 (HDAC2) interact in smooth muscle cells and macrophages as assayed by co-immunoprecipitations. HDAC2 deacetylates CIITA whereas both the HDAC inhibitor trichostatin A (TSA) and over-expression of HDAC2 interfering RNA increase CIITA acetylation. HDAC2 down-regulates CIITA recruitment to target promoters as evidenced by chromatin immunoprecipitation assays, and suppresses MHC II activation and collagen repression mediated by CIITA in luciferase reporter assays. Quantitative PCR reveals that TSA enhances MHC II activation and collagen repression by IFN-gamma. Wild type but not enzyme-deficient HDAC2 promotes the degradation of CIITA protein, whereas TSA and the proteasome inhibitor MG132 restore CIITA activity by stabilizing CIITA protein and increasing its association with target promoters. Furthermore, TSA treatment enhances the association of CIITA with the transcription factor RFX5, which ameliorates the down-regulation of CIITA recruitment to target promoters by HDAC2. In conclusion, our data suggest that HDAC2 antagonizes CIITA activity by committing CIITA to protein degradation and decreasing the interaction of CIITA with RFX5 in a deacetylation-dependent manner. Therefore, modulating CIITA activity by targeting HDAC2 may provide potential anti-atherogenic strategies.

PPARgamma enhances IFNgamma-mediated transcription and rescues the TGFbeta antagonism by stimulating CIITA in vascular smooth muscle cells.

Chronic inflammatory response and active vascular remodeling are two featured pathophysiological events during atherogenesis. Gamma interferon (IFN-gamma) modulates these two processes through transcriptional control of major histocompatibility complex II (MHC II) and collagen type I (COL1A2) genes, mediated by class II transactivator (CIITA). Transforming growth factor (TGF-beta) antagonizes the effect of IFN-gamma in part by dampening the expression of CIITA. Here we report that peroxisome proliferator activated receptor gamma (PPARgamma) enhanced MHC II activation and COL1A2 repression by IFN-gamma while rescuing the antagonism by TGF-beta in a CIITA-dependent manner in human aortic smooth muscle cells judged by quantitative PCR and luciferase reporter assays. PPARgamma exerted its effect by augmenting the levels of CIITA and stimulating CIITA recruitment to target promoters as evidenced by chromatin immunoprecipitation assays. The up-regulation of CIITA levels was the result of PPARgamma-mediated transcriptional activation of CIITA through promoter IV, and increased CIITA protein stability. Thus, our data suggest that PPARgamma could be a key factor in fine-tuning inflammation as well as restructuring of vessel walls during atherogenesis by acting as a "balance tipper" of the differential effects exerted by cytokines.

Association between thyroid function and diabetic nephropathy in euthyroid subjects with type 2 diabetes mellitus: a cross-sectional study in China.

Previous studies have suggested that even in euthyroid subjects, thyroid function may affect the risk factors of diabetic nephropathy (DN). Thus, we investigated the association between thyroid parameters and DN in euthyroid subjects with type 2 diabetes mellitus (T2DM). This was a cross-sectional study of 1,071 euthyroid subjects with T2DM (mean age of 61.90 ± 12.74 years; 622 men). Clinical factors, including levels of free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroid autoantibodies, albumin excretion rate were measured. DN was present in 400 (37.35%) individuals. Patients with DN exhibited higher serum TSH and lower serum FT3 and FT4 levels than those without DN (P<0.05). After adjusting traditional risk factors of DN, the levels of both FT3 (per-SD increase, odds ratio [OR] 0.606 [95% confidence interval (CI), 0.481-0.762], P<0.001) and FT4 (per-SD increase, OR 0.944 [0.894-0.998], P = 0.040) were inversely correlated with DN. Meanwhile, we found that serum TSH levels were positively correlated with DN (per-SD increase, OR1.179 [1.033-1.346], P = 0.015). Low-to-normal thyroid hormones (THs) were also associated with the presence of macroalbuminuria. In conclusion, the relatively low levels of THs were significantly associated with DN in euthyroid subjects with T2DM.

MiR-27b-3p Inhibition Enhances Browning of Epididymal Fat in High-Fat Diet Induced Obese Mice.

Objective: Long-term dysregulation of energy balance is the key component of the obesity epidemic. Given the harm of central obesity and the discovery that beige cells appear within white adipose tissue (WAT), enhancing the energy-expending or "browning" ability of visceral adipose tissue (VAT) has become of therapeutic interest. In this study, we focused on the regulating role of microRNA (miRNA)-27b-3p in mice epididymal white adipose tissue (eWAT) browning. Methods: High-fat diet (HFD) induced obese mice model was constructed. Expression of miR-27b-3p and Ucp1 in eWAT was measured during the course of HFD. Through tail vein injection of antimiR-27b-3p, miR-27b-3p expression was inhibited to analyze the potential role of miR-27b-3p in fat browning and metabolism. Results: miR-27b-3p was predominantly expressed in eWAT and browning ability of eWAT in HFD induced obese mice was impaired. Inhibition of miR-27b-3p enhanced browning capacity of eWAT in mice fed an HFD and led to weight loss and insulin sensitivity improvement. Conclusions: High expression of miR-27b-3p in eWAT inhibits browning ability and leads to visceral fat accumulation. It is suggested miR-27b-3p may become a potential therapeutic option for visceral obesity and its associated diseases.