Glycemic memory associated epigenetic changes

Roles and mechanisms of histone methylation in vascular aging and related diseases

The global aging trend has posed significant challenges, rendering healthcare for older adults a crucial focus in medical research. Among the numerous health concerns related to aging, vascular aging and dysfunction are important risk factors and underlying causes of age-related diseases. Histone methylation and demethylation, which are involved in gene expression and cellular senescence, are closely associated with the occurrence and development of vascular aging. Consequently, this review aimed to identify the role of histone methylation in the pathogenesis of vascular aging and its potential for treating age-related vascular diseases and provided new insights into therapeutic strategies targeting the vascular system.

Epigenetic mechanisms in cardiovascular complications of diabetes: towards future therapies

The pathophysiological mechanisms of cardiovascular disease and microvascular complications in diabetes have been extensively studied, but effective methods of prevention and treatment are still lacking. In recent years, DNA methylation, histone modifications, and non-coding RNAs have arisen as possible mechanisms involved in the development, maintenance, and progression of micro- and macro-vascular complications of diabetes. Epigenetic changes have the characteristic of being heritable or deletable. For this reason, they are now being studied as a therapeutic target for the treatment of diabetes and the prevention or for slowing down its complications, aiming to alleviate the personal and social burden of the disease.This review addresses current knowledge of the pathophysiological links between diabetes and cardiovascular complications, focusing on the role of epigenetic modifications, including DNA methylation and histone modifications. In addition, although the treatment of complications of diabetes with "epidrugs" is still far from being a reality and faces several challenges, we present the most promising molecules and approaches in this field.

lncRNA TUG1 transcript levels and psychological disorders: insights into interplay of glycemic index and glycemic load

BACKGROUND

There is an association between obesity and psychological disorders such as depression, anxiety, and stress. Environmental factors and genetics play a crucial role in this regard. Several long non-coding RNAs (lncRNAs) are involved in the pathophysiology of the nervous system. Additionally, we intend to investigate how dietary glycemic index and load relate to psychological disorders in women with obesity and overweight by identifying the possible interaction with metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and taurine upregulated gene 1 (TUG1).

METHODS

267 overweight or obese women between the ages of 18 and 48 were recruited for the current study. A reliable and validated food frequency questionnaire (FFQ) consisting of 147 items assessed food consumption, glycemic load (GL), and glycemic index (GI). Depression-Anxiety-Stress Scales (DASS-21) were used to assess mental well-being. A real-time polymerase chain reaction (PCR) was used to assess transcript levels for lncRNAs MALAT1 and TUG1.

RESULTS

In obese and overweight women, a positive correlation was found between anxiety and MALAT1 mRNA levels (P = 0.007, CC = 0.178). Age, energy intake, physical activity, total fat, income, marriage, thyroid, and BMI were adjusted, and GI and TUG1 were positively correlated on DASS-21 (β = 0.006, CI = 0.001, 0.01, P = 0.031), depression (β = 0.002, CI = 0.001, 0.004, P = 0.019), Stress (β = 0.003, CI = 0.001, 0.005, P = 0.027). The interaction of GL and TUG1 on stress was also observed (β = 0.03, CI = 0.001, 0.07, P = 0.048).

CONCLUSIONS

The lncRNA TUG1 appears to be associated with depression and stress through interaction with GI and correlated with stress by interaction with GL. To establish this concept, further research is required.

Reversal of high-glucose-induced transcriptional and epigenetic memories through NRF2 pathway activation

Diabetes complications such as nephropathy, retinopathy, or cardiovascular disease arise from vascular dysfunction. In this context, it has been observed that past hyperglycemic events can induce long-lasting alterations, a phenomenon termed "metabolic memory." In this study, we evaluated the genome-wide gene expression and chromatin accessibility alterations caused by transient high-glucose exposure in human endothelial cells (ECs) in vitro. We found that cells exposed to high glucose exhibited substantial gene expression changes in pathways known to be impaired in diabetes, many of which persist after glucose normalization. Chromatin accessibility analysis also revealed that transient hyperglycemia induces persistent alterations, mainly in non-promoter regions identified as enhancers with neighboring genes showing lasting alterations. Notably, activation of the NRF2 pathway through NRF2 overexpression or supplementation with the plant-derived compound sulforaphane, effectively reverses the glucose-induced transcriptional and chromatin accessibility memories in ECs. These findings underscore the enduring impact of transient hyperglycemia on ECs' transcriptomic and chromatin accessibility profiles, emphasizing the potential utility of pharmacological NRF2 pathway activation in mitigating and reversing the high-glucose-induced transcriptional and epigenetic alterations.

Persistent epigenetic signals propel a senescence-associated secretory phenotype and trained innate immunity in CD34+ hematopoietic stem cells from diabetic patients

BACKGROUND

Diabetes-induced trained immunity contributes to the development of atherosclerosis and its complications. This study aimed to investigate in humans whether epigenetic signals involved in immune cell activation and inflammation are initiated in hematopoietic stem/progenitor cells (HSPCs) and transferred to differentiated progeny.

METHODS AND RESULTS

High glucose (HG)-exposure of cord blood (CB)-derived HSPCs induced a senescent-associated secretory phenotype (SASP) characterized by cell proliferation lowering, ROS production, telomere shortening, up-regulation of p21 and p27genes, upregulation of NFkB-p65 transcription factor and increased secretion of the inflammatory cytokines TNFα and IL6. Chromatin immunoprecipitation assay (ChIP) of p65 promoter revealed that H3K4me1 histone mark accumulation and methyltransferase SetD7 recruitment, along with the reduction of repressive H3K9me3 histone modification, were involved in NFkB-p65 upregulation of HG-HSPCs, as confirmed by increased RNA polymerase II engagement at gene level. The differentiation of HG-HSPCs into myeloid cells generated highly responsive monocytes, mainly composed of intermediate subsets (CD14hiCD16+), that like the cells from which they derive, were characterized by SASP features and similar epigenetic patterns at the p65 promoter. The clinical relevance of our findings was confirmed in sternal BM-derived HSPCs of T2DM patients. In line with our in vitro model, T2DM HSPCs were characterized by SASP profile and SETD7 upregulation. Additionally, they generated, after myeloid differentiation, senescent monocytes mainly composed of proinflammatory intermediates (CD14hiCD16+) characterized by H3K4me1 accumulation at NFkB-p65 promoter.

CONCLUSIONS

Hyperglycemia induces marked chromatin modifications in HSPCs, which, once transmitted to the cell progeny, contributes to persistent and pathogenic changes in immune cell function and composition.

Glycated Hemoglobin Trajectories and Their Association With Treatment Outcomes Among Patients With Pulmonary TB in India: A Prospective Cohort Study

BACKGROUND

Transient hyperglycemia is seen commonly during TB treatment, yet its association with unfavorable treatment outcomes is unclear.

RESEARCH QUESTION

Does an association exist between glycated hemoglobin (HbA1c) trajectories and TB treatment outcomes?

STUDY DESIGN AND METHODS

Adults with pulmonary TB were evaluated prospectively for 18 months after the second HbA1c measurement. HbA1c trajectories during the initial 3 months of treatment were defined as follows: persistent euglycemia, HbA1c < 6.5% at baseline and 3-month follow-up; persistent hyperglycemia, HbA1c ≥ 6.5% at baseline and 3-month follow-up; transient hyperglycemia, HbA1c ≥ 6.5% at baseline and < 6.5% at 3-month follow-up; incident hyperglycemia, HbA1c < 6.5% at baseline and ≥ 6.5% at 3-month follow-up. Multivariable Poisson regression was used to measure the association between HbA1c trajectories and unfavorable treatment outcomes of failure, recurrence, and all-cause mortality.

RESULTS

Of the 587 participants, 443 participants (76%) had persistent euglycemia, 118 participants (20%) had persistent hyperglycemia, and 26 participants (4%) had transient hyperglycemia. One participant had incident hyperglycemia and was excluded. Compared with participants with persistent euglycemia, those with transient hyperglycemia showed a twofold higher risk of experiencing an unfavorable treatment outcome (adjusted incidence rate ratio [aIRR], 2.07; 95% CI, 1.04-4.15) after adjusting for confounders including diabetes treatment, and BMI; we did not find a significant association with persistent hyperglycemia (aIRR, 1.64; 95% CI, 0.71-3.79). Diabetes treatment was associated with a significantly lower risk of unfavorable treatment outcomes (aIRR, 0.38; 95% CI, 0.15-0.95).

INTERPRETATION

Transient hyperglycemia and lack of diabetes treatment was associated with a higher risk of unfavorable treatment outcomes in adults with pulmonary TB.

Novel small molecules inhibit proteotoxicity and inflammation: Mechanistic and therapeutic implications for Alzheimer's Disease, healthspan and lifespan- Aging as a consequence of glycolysis

Inflammation drives many age-related, especially neurological, diseases, and likely mediates age-related proteotoxicity. For example, dementia due to Alzheimer's Disease (AD), cerebral vascular disease, many other neurodegenerative conditions is increasingly among the most devastating burdens on the American (and world) health system and threatens to bankrupt the American health system as the population ages unless effective treatments are developed. Dementia due to either AD or cerebral vascular disease, and plausibly many other neurodegenerative and even psychiatric conditions, is driven by increased age-related inflammation, which in turn appears to mediate Abeta and related proteotoxic processes. The functional significance of inflammation during aging is also supported by the fact that Humira, which is simply an antibody to the pro-inflammatory cytokine TNF-a, is the best-selling drug in the world by revenue. These observations led us to develop parallel high-throughput screens to discover small molecules which inhibit age-related Abeta proteotoxicity in a C. elegans model of AD AND LPS-induced microglial TNF-a. In the initial screen of 2560 compounds (Microsource Spectrum library) to delay Abeta proteotoxicity, the most protective compounds were, in order, phenylbutyrate, methicillin, and quetiapine, which belong to drug classes (HDAC inhibitors, beta lactam antibiotics, and tricyclic antipsychotics, respectably) already robustly implicated as promising to protect in neurodegenerative diseases, especially AD. RNAi and chemical screens indicated that the protective effects of HDAC inhibitors to reduce Abeta proteotoxicity are mediated by inhibition of HDAC2, also implicated in human AD, dependent on the HAT Creb binding protein (Cbp), which is also required for the protective effects of both dietary restriction and the daf-2 mutation (inactivation of IGF-1 signaling) during aging. In addition to methicillin, several other beta lactam antibiotics also delayed Abeta proteotoxicity and reduced microglial TNF-a. In addition to quetiapine, several other tricyclic antipsychotic drugs also delayed age-related Abeta proteotoxicity and increased microglial TNF-a, leading to the synthesis of a novel congener, GM310, which delays Abeta as well as Huntingtin proteotoxicity, inhibits LPS-induced mouse and human microglial and monocyte TNF-a, is highly concentrated in brain after oral delivery with no apparent toxicity, increases lifespan, and produces molecular responses highly similar to those produced by dietary restriction, including induction of Cbp inhibition of inhibitors of Cbp, and genes promoting a shift away from glycolysis and toward metabolism of alternate (e.g., lipid) substrates. GM310, as well as FDA-approved tricyclic congeners, prevented functional impairments and associated increase in TNF-a in a mouse model of stroke. Robust reduction of glycolysis by GM310 was functionally corroborated by flux analysis, and the glycolytic inhibitor 2-DG inhibited microglial TNF-a and other markers of inflammation, delayed Abeta proteotoxicity, and increased lifespan. These results support the value of phenotypic screens to discover drugs to treat age-related, especially neurological and even psychiatric diseases, including AD and stroke, and to clarify novel mechanisms driving neurodegeneration (e.g., increased microglial glycolysis drives neuroinflammation and subsequent neurotoxicity) suggesting novel treatments (selective inhibitors of microglial glycolysis).

Set7 methyltransferase roles in myocardial protection from chronic stressors

Epigenome changes in chronic states of cardiovascular stress including diabetes, pressure overload and cardiomyopathies frequently involve changes in open chromatin and post-translation modifications of histone lysine residues at specific amino acid positions by acetylation, methylation and phosphorylation. Since the discovery of Set7 as an important regulator of histone H3 lysine 4 methylation state, there has been wide interest in its role in cardiovascular remodeling and cardiac dysfunction. Recent transcriptome and Fourier transform infrared spectroscopy analyses and in vivo assessments of cardiac function by Lunardon and colleagues now reveal a clear role of Set7 in the regulation of the extracellular matrix composition and cardiac hypertrophy in response to chronic isoproterenol induced cardiac stress.

Biological age and environmental risk factors for dementia and stroke: Molecular mechanisms

Since the development of antibiotics and vaccination, as well as major improvements in public hygiene, the main risk factors for morbidity and mortality are age and chronic exposure to environmental factors, both of which can interact with genetic predispositions. As the average age of the population increases, the prevalence and costs of chronic diseases, especially neurological conditions, are rapidly increasing. The deleterious effects of age and environmental risk factors, develop chronically over relatively long periods of time, in contrast to the relatively rapid deleterious effects of infectious diseases or accidents. Of particular interest is the hypothesis that the deleterious effects of environmental factors may be mediated by acceleration of biological age. This hypothesis is supported by evidence that dietary restriction, which universally delays age-related diseases, also ameliorates deleterious effects of environmental factors. Conversely, both age and environmental risk factors are associated with the accumulation of somatic mutations in mitotic cells and epigenetic modifications that are a measure of "biological age", a better predictor of age-related morbidity and mortality than chronological age. Here we review evidence that environmental risk factors such as smoking and air pollution may also drive neurological conditions, including Alzheimer's Disease, by the acceleration of biological age, mediated by cumulative and persistent epigenetic effects as well as somatic mutations. Elucidation of such mechanisms could plausibly allow the development of interventions which delay deleterious effects of both aging and environmental risk factors.

Positive feedback loop of miR-320 and CD36 regulates the hyperglycemic memory-induced diabetic diastolic cardiac dysfunction

Intensive glycemic control is insufficient for reducing the risk of heart failure among patients with diabetes mellitus (DM). While the "hyperglycemic memory" phenomenon is well documented, little is known about its underlying mechanisms. In this study, a type 1 DM model was established in C57BL/6 mice using streptozotocin (STZ). Leptin receptor-deficient (db/db) mice were used as a model of type 2 DM. A type 9 adeno-associated virus was used to overexpress or knock down miR-320 in vivo. Diastolic dysfunction was observed in the type 1 DM mice with elevated miR-320 expression. However, glycemic control using insulin failed to reverse diastolic dysfunction. miR-320 knockdown protected against STZ-induced diastolic dysfunction. Similar results were observed in the type 2 DM mice. In vitro, we found that miR-320 promoted CD36 expression, which in turn induced further miR-320 expression. CD36 was rapidly induced by hyperglycemia at protein level compared with the much slower induction of miR-320, suggesting a positive feedback loop of CD36/miR-320 with CD36 protein induction as the initial triggering event. In conclusion, in DM-induced cardiac injury, miR-320 and CD36 mutually enhance each other's expression, leading to a positive feedback loop and a sustained hyperlipidemic state in the heart.

Glucose variability during the early course of acute pancreatitis predicts two‐year probability of new‐onset diabetes: A prospective longitudinal cohort study

Background

Acute pancreatitis (AP) is the largest contributor to diabetes of the exocrine pancreas. However, there is no accurate predictor at the time of hospitalisation for AP to identify individuals at high risk for new‐onset diabetes.

Objective

To investigate the accuracy of indices of glucose variability (GV) during the early course of AP in predicting the glycated haemoglobin (HbA1c) trajectories during follow‐up.

Methods

This was a prospective longitudinal cohort study of patients without diabetes at the time of hospitalisation for AP. Fasting blood glucose was regularly measured over the first 72 h of hospital admission. The study endpoint was the HbA1c trajectories ‐ high‐increasing, moderate‐stable, normal‐stable ‐ over two years of follow‐up. Multinomial logistic regression analyses were conducted to investigate the associations between several common GV indices and the HbA1c trajectories, adjusting for covariates (age, sex, and body mass index). A sensitivity analysis constrained to patients with non‐necrotising AP was conducted.

Results

A total of 120 consecutive patients were studied. All patients in the high‐increasing HbA1c trajectory group had new‐onset diabetes at 18 and 24 months of follow‐up. Glycaemic lability index had the strongest significant direct association (adjusted odds ratio = 13.69; p = 0.040) with the high‐increasing HbA1c trajectory. High admission blood glucose, standard deviation of blood glucose, and average real variability significantly increased the patients' odds of taking the high‐increasing HbA1c trajectory by at least two‐times. Admission blood glucose, but not the other GV indices, had a significant direct association (adjusted odds ratio = 1.46; p = 0.034) with the moderate‐stable HbA1c trajectory. The above findings did not change materially in patients with non‐necrotising AP alone.

Conclusions

High GV during the early course of AP gives a prescient warning of worsening HbA1c pattern and new‐onset diabetes after hospital discharge. Determining GV during hospitalisation could be a relatively straightforward approach to early identification of individuals at high risk for new‐onset diabetes after AP.

Hyperglycemic memory in diabetic cardiomyopathy

Cardiovascular diseases account for approximately 80% of deaths among individuals with diabetes mellitus, with diabetic cardiomyopathy as the major diabetic cardiovascular complication. Hyperglycemia is a symptom that abnormally activates multiple downstream pathways and contributes to cardiac hypertrophy, fibrosis, apoptosis, and other pathophysiological changes. Although glycemic control has long been at the center of diabetes therapy, multicenter randomized clinical studies have revealed that intensive glycemic control fails to reduce heart failure-associated hospitalization and mortality in patients with diabetes. This finding indicates that hyperglycemic stress persists in the cardiovascular system of patients with diabetes even if blood glucose level is tightly controlled to the normal level. This process is now referred to as hyperglycemic memory (HGM) phenomenon. We briefly reviewed herein the current advances that have been achieved in research on the underlying mechanisms of HGM in diabetic cardiomyopathy.

Alterations of transcriptome expression, cell cycle, and mitochondrial superoxide reveal foetal endothelial dysfunction in Saudi women with gestational diabetes mellitus

Gestational diabetes mellitus (GDM) affects one in four Saudi women and is associated with high risks of cardiovascular diseases in both the mother and foetus. It is believed that endothelial cells (ECs) dysfunction initiates these diabetic complications. In this study, differences in the transcriptome profiles, cell cycle distribution, and mitochondrial superoxide (MTS) between human umbilical vein endothelial cells (HUVECs) from GDM patients and those from healthy (control) subjects were analysed. Transcriptome profiles were generated using high-density expression microarray. The selected four altered genes were validated using qRT-PCR. MTS and cell cycle were analysed by flow cytometry. A total of 84 altered genes were identified, comprising 52 upregulated and 32 downregulated genes in GDM.HUVECs. Our selection of the four interested altered genes (TGFB2, KITLG, NEK7, and IGFBP5) was based on the functional network analysis, which revealed that these altered genes are belonging to the highest enrichment score associated with cellular function and proliferation; all of which may contribute to ECs dysfunction. The cell cycle revealed an increased percentage of cells in the G2/M phase in GDM.HUVECs, indicating cell cycle arrest. In addition, we found that GDM.HUVECs had increased MTS generation. In conclusion, GDM induces persistent impairment of the biological functions of foetal ECs, as evidenced by analyses of transcriptome profiles, cell cycle, and MTS even after ECs culture in vitro for several passages under normal glucose conditions.

Diabetes and Cancer: Metabolic Association, Therapeutic Challenges, and the Role of Natural Products

Cancer is considered the second leading cause of death worldwide and in 2018 it was responsible for approximately 9.6 million deaths. Globally, about one in six deaths are caused by cancer. A strong correlation was found between diabetes mellitus and carcinogenesis with the most evident correlation was with type 2 diabetes mellitus (T2DM). Research has proven that elevated blood glucose levels take part in cell proliferation and cancer cell progression. However, limited studies were conducted to evaluate the efficiency of conventional therapies in diabetic cancer patients. In this review, the correlation between cancer and diabetes will be discussed and the mechanisms by which the two diseases interact with each other, as well as the therapeutics challenges in treating patients with diabetes and cancer with possible solutions to overcome these challenges. Natural products targeting both diseases were discussed with detailed mechanisms of action. This review will provide a solid base for researchers and physicians to test natural products as adjuvant alternative therapies to treat cancer in diabetic patients.

NF-κB and STAT3 co-operation enhances high glucose induced aggressiveness of cholangiocarcinoma cells

AIMS

The present report aimed to investigate the underlying genes and pathways of high glucose driving cholangiocarcinoma (CCA) aggressiveness.

MAIN METHODS

We screened and compared the gene expression profiles obtained by RNA sequencing, of CCA cells cultured in high and normal glucose. Results from the transcriptomic analysis were confirmed in additional cell lines using in vitro migration-invasion assay, Western blotting and immunocytofluorescence.

KEY FINDINGS

Data indicated that high glucose increased the expression of interleukin-1β (IL-1β), an upstream regulator of nuclear factor-κB (NF-κB) pathway, through the nuclear localization of NF-κB. High glucose-induced NF-κB increased the migration and invasion of CCA cells and the expression of downstream NF-κB targeted genes associated with aggressiveness, including interleukin-6, a potent triggering signal of the signal transducer and activator of transcription 3 (STAT3) pathway. Such effects were reversed by inhibiting NF-κB nuclear translocation which additionally reduced the phosphorylation of STAT3 at Y705.

SIGNIFICANCE

These results indicate that NF-κB is activated by high glucose and they suggest that NF-κB interaction with STAT3 enhances CCA aggressiveness. Therefore, targeting multiple pathways such as STAT3 and NF-κB might improve CCA treatment outcome especially in condition such as hyperglycemia.

Trained Immunity in Atherosclerotic Cardiovascular Disease

Atherosclerosis is characterized by incessant inflammation in the arterial wall in which monocytes and macrophages play a crucial role. During the past few years, it has been reported that cells from the innate immune system can develop a long-lasting proinflammatory phenotype after brief stimulation not only with microbial products but also endogenous atherogenic stimuli. This persistent hyperactivation of the innate immune system is termed trained immunity and can contribute to the pathophysiology of atherosclerosis. Trained immunity is mediated via epigenetic and metabolic reprogramming and occurs both in mature innate immune cells as well as their bone marrow progenitors. In addition to monocytes, other innate immune and nonimmune cells involved in different stages of atherosclerosis can develop comparable memory characteristics. This mechanism provides exciting novel pharmacological targets that can be used to prevent or treat cardiovascular diseases.

Insulin Resistance at the Crossroad of Alzheimer Disease Pathology: A Review

Insulin plays a major neuroprotective and trophic function for cerebral cell population, thus countering apoptosis, beta-amyloid toxicity, and oxidative stress; favoring neuronal survival; and enhancing memory and learning processes. Insulin resistance and impaired cerebral glucose metabolism are invariantly reported in Alzheimer's disease (AD) and other neurodegenerative processes. AD is a fatal neurodegenerative disorder in which progressive glucose hypometabolism parallels to cognitive impairment. Although AD may appear and progress in virtue of multifactorial nosogenic ingredients, multiple interperpetuative and interconnected vicious circles appear to drive disease pathophysiology. The disease is primarily a metabolic/energetic disorder in which amyloid accumulation may appear as a by-product of more proximal events, especially in the late-onset form. As a bridge between AD and type 2 diabetes, activation of c-Jun N-terminal kinase (JNK) pathway with the ensued serine phosphorylation of the insulin response substrate (IRS)-1/2 may be at the crossroads of insulin resistance and its subsequent dysmetabolic consequences. Central insulin axis bankruptcy translates in neuronal vulnerability and demise. As a link in the chain of pathogenic vicious circles, mitochondrial dysfunction, oxidative stress, and peripheral/central immune-inflammation are increasingly advocated as major pathology drivers. Pharmacological interventions addressed to preserve insulin axis physiology, mitochondrial biogenesis-integral functionality, and mitophagy of diseased organelles may attenuate the adjacent spillover of free radicals that further perpetuate mitochondrial damages and catalyze inflammation. Central and/or peripheral inflammation may account for a local flood of proinflammatory cytokines that along with astrogliosis amplify insulin resistance, mitochondrial dysfunction, and oxidative stress. All these elements are endogenous stressor, pro-senescent factors that contribute to JNK activation. Taken together, these evidences incite to identify novel multi-mechanistic approaches to succeed in ameliorating this pandemic affliction.

Diabetes mellitus and oral cancer/oral potentially malignant disorders: A systematic review and meta-analysis

The objective was to evaluate current evidence on the prevalence and risk of oral cancer and potentially malignant oral disorders among patients with diabetes mellitus. We searched PubMed, Embase, Web of Science, and Scopus for observational studies published before November 2019. We evaluated the study quality using GRADE, QUIPS, and a specific method for systematic reviews addressing prevalence questions. Meta-analyses were conducted, and heterogeneity and publication bias were examined. A total of 1,489 studies were found, 116 analyzed in full text, 52 included in qualitative synthesis and 49 meta-analyzed. Pooled prevalence (PP) of oral cancer in patients with diabetic was 0.25% (95% CI = 0.15-0.39)-250 per 100,000 patients with diabetes mellitus -with a greater chance of oral cancer among patients with diabetes mellitus (OR = 1.41 [95% CI = 1.10-1.81], p = .007). Patients with oral cancer and diabetes mellitus had a higher mortality than controls (HR = 2.09 [95%CI = 1.36-3.22], p = .001). Leukoplakia had a PP = 2.49% (95% CI = 1.14-4.29)-2,490 per 100,000 patients with diabetes mellitus -(OR = 4.34 [95% CI = 1.14-16.55], p = .03). A PP of 2.72 (95% CI = 1.64-4.02) was obtained for oral lichen planus among patients with diabetic -2,720 per 100,000 patients with diabetes mellitus (OR = 1.87 [95% CI = 1.37-2.57], p < .001). A low PP was estimated for erythroplakia (0.02%[95%CI = 0.00-0.12]-20 per 100,000 patients with diabetes mellitus. In conclusion, patients with diabetes mellitus have a higher prevalence and greater chance of oral cancer and OPMD development in comparison with non-diabetic patients. In addition, patients with oral cancer suffering from diabetes mellitus have a higher mortality compared to non-diabetic patients with oral cancer.

LSD1 mediates metabolic reprogramming by glucocorticoids during myogenic differentiation

The metabolic properties of cells are formed under the influence of environmental factors such as nutrients and hormones. Although such a metabolic program is likely initiated through epigenetic mechanisms, the direct links between metabolic cues and activities of chromatin modifiers remain largely unknown. In this study, we show that lysine-specific demethylase-1 (LSD1) controls the metabolic program in myogenic differentiation, under the action of catabolic hormone, glucocorticoids. By using transcriptomic and epigenomic approaches, we revealed that LSD1 bound to oxidative metabolism and slow-twitch myosin genes, and repressed their expression. Consistent with this, loss of LSD1 activity during differentiation enhanced the oxidative capacity of myotubes. By testing the effects of various hormones, we found that LSD1 levels were decreased by treatment with the glucocorticoid dexamethasone (Dex) in cultured myoblasts and in skeletal muscle from mice. Mechanistically, glucocorticoid signaling induced expression of a ubiquitin E3 ligase, JADE-2, which was responsible for proteasomal degradation of LSD1. Consequently, in differentiating myoblasts, chemical inhibition of LSD1, in combination with Dex treatment, synergistically de-repressed oxidative metabolism genes, concomitant with increased histone H3 lysine 4 methylation at these loci. These findings demonstrated that LSD1 serves as an epigenetic regulator linking glucocorticoid action to metabolic programming during myogenic differentiation.

Adenosine kinase and cardiovascular fetal programming in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a detrimental condition for human pregnancy associated with endothelial dysfunction and endothelial inflammation in the fetoplacental vasculature and leads to increased cardio-metabolic risk in the offspring. In the fetoplacental vasculature, GDM is associated with altered adenosine metabolism. Adenosine is an important vasoactive molecule and is an intermediary and final product of transmethylation reactions in the cell. Adenosine kinase is the major regulator of adenosine levels. Disruption of this enzyme is associated with alterations in methylation-dependent gene expression regulation mechanisms, which are associated with the fetal programming phenomenon. Here we propose that cellular and molecular alterations associated with GDM can dysregulate adenosine kinase leading to fetal programming in the fetoplacental vasculature. This can contribute to the cardio-metabolic long-term consequences observed in offspring after exposure to GDM.

Linking type 2 diabetes and gynecological cancer: an introductory overview

Type 2 diabetes (T2D) is a chronic disease with a growing prevalence and a leading cause of death in many countries. Several epidemiological studies observed an association between T2D and increased risk of many types of cancer, such as gynecologic neoplasms (endometrial, cervical, ovarian and vulvar cancer). Insulin resistance, chronic inflammation and high free ovarian steroid hormones are considered the possible mechanisms behind this complex relationship. A higher risk of endometrial cancer was observed in T2D, even though this association largely attenuated after adjusting for obesity. A clear relationship between the incidence of cervical cancer (CC) and T2D has still not be determined; however T2D might have an impact on prognosis in patients with CC. To date, studies on the association between T2D and ovarian cancer (OC) are limited. The effect of pre-existing diabetes on cancer-specific mortality has been evaluated in several studies, with less clear results. Other epidemiological and experimental studies focused on the potential role of diabetes medications, mainly metformin, in cancer development in women. The correct understanding of the link between T2D and gynecologic cancer risk and mortality is currently imperative to possibly modify screening and diagnostic-therapeutic protocols in the future.

Challenges and perspectives in the treatment of diabetes associated breast cancer

Type 2 diabetes mellitus is one of the most common chronic disease worldwide and affects all cross-sections of the society including children, women, youth and adults. Scientific evidence has linked diabetes to higher incidence, accelerated progression and increased aggressiveness of different cancers. Among the different forms of cancer, research has reinforced a link between diabetes and the risk of breast cancer. Some studies have specifically linked diabetes to the highly aggressive, triple negative breast cancers (TNBCs) which do not respond to conventional hormonal/HER2 targeted interventions, have chances of early recurrence, metastasize, tend to be more invasive in nature and develop drug resistance. Commonly used anti-diabetic drugs, such as metformin, have recently gained importance in the treatment of breast cancer due to their proposed anti-cancer properties. Here we discuss the link between diabetes and breast cancer, the metabolic disturbances in diabetes that support the development of breast cancer, the challenges involved and future perspective and directions. We link the three main metabolic disturbances (dyslipidemia, hyperinsulinemia and hyperglycemia) that occur in diabetes to potential aberrant molecular pathways that may lead to the development of an oncogenic phenotype of the breast tissue, thereby leading to acceleration of cell growth, proliferation, migration, inflammation, angiogenesis, EMT and metastasis and inhibition of apoptosis in breast cancer cells. Furthermore, managing diabetes and treating cancer using a combination of anti-diabetic and classical anti-cancer drugs should prove to be more efficient in the treatment diabetes associated cancers.

Body weight regulation, socioeconomic status and epigenetic alterations

Obesity is a complex disease which has reached epidemic dimensions. Thus, prevention of excessive weight gain and associated metabolic and cardiovascular diseases has to start as early in life as possible. The impact of epigenetic mechanisms on the regulation of genes involved in obesity is increasingly recognized. On the other hand, it is well known that socioeconomic factors influence the risk for obesity. These factors can also have an impact on epigenetic gene regulation. There is increasing body of evidence that several factors and interventions addressing extragenetic causes of obesity may not only improve individual health, but also the health of future generations by epigenetic alterations. Our current understanding of epigenetic changes has shown that many of them are potentially reversible, i.e. by physical exercise, by pharmacological treatment, by environmental factors or nutrition, or even by influencing socioeconomic factors, which might have impact on improving health in future generations by avoiding epigenetic dysregulation. In this review we present the current state of the art with regard to the interplay between social determinants, weight status and epigenetic alterations.

NADPH oxidase 4 and endothelial nitric oxide synthase contribute to endothelial dysfunction mediated by histone methylations in metabolic memory

"Metabolic memory" is identified as a phenomenon that transient hyperglycemia can be remembered by vasculature for quite a long term even after reestablishment of normoglycemia. NADPH oxidases (Noxs) and endothelial nitric oxide synthase (eNOS) are important enzymatic sources of reactive oxygen species (ROS) in diabetic vasculature. The aim of this study is to explore the roles of epigenetics and ROS derived from Noxs and eNOS in the metabolic memory. In this study, we demonstrated that vascular ROS was continuously activated in endothelium induced by transient high glucose, as well as sustained vascular endothelial dysfunction. The Nox4 and uncoupled eNOS are the major sources of ROS, while inhibition of Nox4 and eNOS significantly attenuated oxidative stress and almost recovered the endothelial function in metabolic memory. Furthermore, the aberrant histone methylation (H3K4me1, H3K9me2, and H3K9me3) at promoters of Nox4 and eNOS are the main causes for the persistent up-regulation of these two genes. Modifying the histone methylation could reduce the expression levels of Nox4 and eNOS, thus obviously attenuating endothelial dysfunction. These results indicate that histone methylation of Nox4 and eNOS play a key role in metabolic memory and may be the potential intervention targets for metabolic memory.

New-Onset Diabetes After Acute and Critical Illness: A Systematic Review

Hyperglycemia is commonly observed during acute and critical illness. Recent studies have investigated the risk of developing diabetes after acute and critical illness, but the relationship between degree of in-hospital hyperglycemia and new-onset diabetes has not been investigated. This study examines the evidence for the relationship between in-hospital hyperglycemia and prevalence of new-onset diabetes after acute and critical illness. A literature search was performed of the MEDLINE, EMBASE, and Scopus databases for relevant studies published from January 1, 2000, through August 4, 2016. Patients with no history of diabetes before hospital discharge were included in the systematic review. In-hospital glucose concentration was classified as normoglycemia, mild hyperglycemia, or severe hyperglycemia for the meta-analysis. Twenty-three studies were included in the systematic review, and 18 of these (111,078 patients) met the eligibility criteria for the meta-analysis. The prevalence of new-onset diabetes was significantly related to in-hospital glucose concentration and was 4% (95% CI, 2%-7%), 12% (95% CI, 9%-15%), and 28% (95% CI, 18%-39%) for patients with normoglycemia, mild hyperglycemia, and severe hyperglycemia, respectively. The prevalence of new-onset diabetes was not influenced by disease setting, follow-up duration, or study design. In summary, this study found stepwise growth in the prevalence of new-onset diabetes with increasing in-hospital glucose concentration. Patients with severe hyperglycemia are at the highest risk, with 28% developing diabetes after hospital discharge.

Inhibitors of Protein Methyltransferases and Demethylases

Post-translational modifications of histones by protein methyltransferases (PMTs) and histone demethylases (KDMs) play an important role in the regulation of gene expression and transcription and are implicated in cancer and many other diseases. Many of these enzymes also target various nonhistone proteins impacting numerous crucial biological pathways. Given their key biological functions and implications in human diseases, there has been a growing interest in assessing these enzymes as potential therapeutic targets. Consequently, discovering and developing inhibitors of these enzymes has become a very active and fast-growing research area over the past decade. In this review, we cover the discovery, characterization, and biological application of inhibitors of PMTs and KDMs with emphasis on key advancements in the field. We also discuss challenges, opportunities, and future directions in this emerging, exciting research field.

Remodelling of the hepatic epigenetic landscape of glucose-intolerant rainbow trout (Oncorhynchus mykiss) by nutritional status and dietary carbohydrates

The rainbow trout, a carnivorous fish, displays a 'glucose-intolerant' phenotype revealed by persistent hyperglycaemia when fed a high carbohydrate diet (HighCHO). Epigenetics refers to heritable changes in gene activity and is closely related to environmental changes and thus to metabolism adjustments governed by nutrition. In this study we first assessed in the trout liver whether and how nutritional status affects global epigenome modifications by targeting DNA methylation and histone marks previously reported to be affected in metabolic diseases. We then examined whether dietary carbohydrates could affect the epigenetic landscape of duplicated gluconeogenic genes previously reported to display changes in mRNA levels in trout fed a high carbohydrate diet. We specifically highlighted global hypomethylation of DNA and hypoacetylation of H3K9 in trout fed a HighCHO diet, a well-described phenotype in diabetes. g6pcb2 ohnologs were also hypomethylated at specific CpG sites in these animals according to their up-regulation. Our findings demonstrated that the hepatic epigenetic landscape can be affected by both nutritional status and dietary carbohydrates in trout. The mechanism underlying the setting up of these epigenetic modifications has now to be explored in order to improve understanding of its impact on the glucose intolerant phenotype in carnivorous teleosts.

Long-lasting partnership between insulin resistance and endothelial dysfunction: role of metabolic memory

BACKGROUND AND PURPOSE

The persistence of deleterious effects of hyperglycaemia even after glucose normalization is referred to as 'metabolic memory'. However, similar persistent effects of the metabolic consequences of a high fat diet (HFD) have not been described.

EXPERIMENTAL APPROACH

Rats were given a normal pellet diet (NPD) or a HFD for 3 months. The animals from the HFD group were then returned to the NPD to observe the long-term effects of insulin resistance. Endothelial dysfunction was assessed by carbachol-mediated vasorelaxation and eNOS phosphorylation.

KEY RESULTS

As expected, HFD consumption resulted in insulin resistance and endothelial dysfunction. Phosphorylation of eNOS at S1177 was decreased in HFD rats, compared with that in the NPD group. Rats on 3 months of HFD showed glucose intolerance and impaired insulin sensitivity and were then switched back to NPD (REV group) . Levels of cholesterol and triglyceride, and adiposity returned to normal in REV rats. However, endothelium-dependent vascular responses to carbachol which were impaired in HFD rats, continued to be impaired in REV rats. Similarly, decreased eNOS phosphorylation after HFD was not improved after 1 or 6 months of REV.

CONCLUSIONS AND IMPLICATIONS

Our data indicate that returning to NPD did not improve the insulin sensitivity or the endothelial dysfunction induced by HFD. Although some biochemical parameters responsible for insulin resistance and endothelial dysfunction were normalized, molecular and vascular abnormalities, involving NO, persisted for several months, highlighting the long-lasting effects of metabolic memory.

The PTIP-Associated Histone Methyltransferase Complex Prevents Stress-Induced Maladaptive Cardiac Remodeling

Pressure overload induces stress-induced signaling pathways and a coordinated transcriptional response that begets concentric cardiac hypertrophy. Although concentric hypertrophy initially attenuates wall stress and maintains cardiac function, continued stress can result in maladaptive cardiac remodeling. Cardiac remodeling is orchestrated by transcription factors that act within the context of an epigenetic landscape. Since the epigenetic landscape serves as a molecular link between environmental factors (stress) and cellular phenotype (disease), defining the role of the epigenome in the development and progression of cardiac remodeling could lead to new therapeutic approaches. In this study, we hypothesized that the epigenetic landscape is important in the development of cardiac hypertrophy and the progression to maladaptive remodeling. To demonstrate the importance of the epigenome in HF, we targeted the PTIP-associated histone methyltransferase complex in adult cardiac myocytes. This complex imparts histone H3 lysine 4 (H3K4) methylation marks at actively expressed genes. We subjected PTIP null (PTIP-) mice to 2 weeks of transverse aortic constriction, a stress that induces concentric hypertrophy in control mice (PTIP+). PTIP- mice have a maladaptive response to 2wk of transverse aortic constriction (TAC)-induced pressure overload characterized by cardiac dilatation, decreased LV function, cardiac fibrosis, and increased cell death. PTIP deletion resulted in altered stress-induced gene expression profiles including blunted expression of ADRA1A, ADRA1B, JUN, ATP2A2, ATP1A2, SCN4B, and CACNA1G. These results suggest that H3K4 methylation patterns and the complexes that regulate them, specifically the PTIP-associated HMT, are necessary for the adaptive response to TAC.

Thymosin β4 attenuates early diabetic nephropathy in a mouse model of type 2 diabetes mellitus

The chronic inflammatory processes and endothelial dysfunction play important roles in the development of diabetic nephropathy (DN); the study aims to evaluate the effect of thymosin β4 (Tβ4), which has apparent anti-inflammatory properties and is capable of improving endothelial dysfunction, in early DN in a mouse model of type 2 diabetes mellitus. KK Cg-Ay/J (KK) mice, aged 12-14 weeks, were divided into the following groups: KK control group that was treated with saline; KK Tβ4 group that was treated with Tβ4 100 ng/10 g of intraperitoneal injection once a day. Nondiabetic age-matched C57BL mice were used as additional normal control and also treated with Tβ4. The urinary albumin/creatinine ratio (ACR), plasma urea nitrogen and creatinine, body weight, fasting blood glucose and 2-hour blood glucose during oral glucose tolerance testing, blood hemoglobin A1c, cholesterol, and triglyceride were determined at baseline time and 12 weeks after Tβ4 treatment for phenotypic characterizations. The KK Tβ4 group had reduced the mean fasting blood glucose, 2-hour blood glucose during oral glucose tolerance testing, hemoglobin A1c, and triglyceride levels compared with that in the KK control group (P < 0.05). Tβ4 treatment markedly reduced ACR (KK Tβ4 = 328.54 ± 46.14 mg/g vs. KK control = 540.34 ± 50.31 mg/g, P < 0.05). Tβ4 also significantly ameliorated renal pathological changes of KK Tβ4 mice as compared with that in KK control mice. Tβ4 treatment did not affect glucose homeostasis and urinary ACR and glomeruli of C57BL mice. These data in a novel mouse model of DN suggest that Tβ4 may ameliorate renal damage. This peptide may be a novel potential alternative agent for treatment of DN.

Selective inhibitors of protein methyltransferases

Mounting evidence suggests that protein methyltransferases (PMTs), which catalyze methylation of histone and nonhistone proteins, play a crucial role in diverse biological processes and human diseases. In particular, PMTs have been recognized as major players in regulating gene expression and chromatin state. PMTs are divided into two categories: protein lysine methyltransferases (PKMTs) and protein arginine methyltransferases (PRMTs). There has been a steadily growing interest in these enzymes as potential therapeutic targets and therefore discovery of PMT inhibitors has also been pursued increasingly over the past decade. Here, we present a perspective on selective, small-molecule inhibitors of PMTs with an emphasis on their discovery, characterization, and applicability as chemical tools for deciphering the target PMTs' physiological functions and involvement in human diseases. We highlight the current state of PMT inhibitors and discuss future directions and opportunities for PMT inhibitor discovery.

Disease modeling and phenotypic drug screening for diabetic cardiomyopathy using human induced pluripotent stem cells

Diabetic cardiomyopathy is a complication of type 2 diabetes, with known contributions of lifestyle and genetics. We develop environmentally and genetically driven in vitro models of the condition using human-induced-pluripotent-stem-cell-derived cardiomyocytes. First, we mimic diabetic clinical chemistry to induce a phenotypic surrogate of diabetic cardiomyopathy, observing structural and functional disarray. Next, we consider genetic effects by deriving cardiomyocytes from two diabetic patients with variable disease progression. The cardiomyopathic phenotype is recapitulated in the patient-specific cells basally, with a severity dependent on their original clinical status. These models are incorporated into successive levels of a screening platform, identifying drugs that preserve cardiomyocyte phenotype in vitro during diabetic stress. In this work, we present a patient-specific induced pluripotent stem cell (iPSC) model of a complex metabolic condition, showing the power of this technique for discovery and testing of therapeutic strategies for a disease with ever-increasing clinical significance.

Epigenetic modifications of Keap1 regulate its interaction with the protective factor Nrf2 in the development of diabetic retinopathy

PURPOSE

Diabetes induces oxidative imbalance in the retina and impairs Nrf2-mediated antioxidant response, and elevates Keap1, the cytoplasmic repressor of Nrf2. The goal of this study was to understand the role of epigenetic modifications at Keap1 promoter in regulation of Nrf2 function.

METHODS

The effect of high glucose on the binding of transcriptional factor Sp1 at Keap1 promoter and histone methylation status of the promoter was investigated in retinal endothelial cells. Role of histone methylation was confirmed in cells transfected with siRNA of methyltransferase enzyme Set7/9 (SetD7). In vitro results were confirmed in the retina from streptozotocin-induced diabetic rats. The role of epigenetic modifications of Keap1 promoter in the metabolic memory was examined in rats maintained in poor control for 3 months followed by good control for 3 months.

RESULTS

Hyperglycemia increased the binding of Sp1 at Keap1 promoter, and enriched H3K4me1 and activated SetD7. SetD7-siRNA prevented increase in Sp1 binding at Keap1 promoter and Keap1 expression, and ameliorated decrease in Nrf2-regulated antioxidant genes. Cessation of hyperglycemia failed to attenuate increased binding of Sp1 at Keap1, and the promoter continued to be methylated with increased expression of Keap1 and decreased expression of Nrf2-regulated genes.

CONCLUSIONS

Epigenetic modifications at Keap1 promoter by SetD7 facilitate its binding with Sp1, increasing its expression. Keap1 restrains Nrf2 in the cytosol, impairing its transcriptional activity. Reversal of hyperglycemia fails to provide any benefit to epigenetic modifications of Keap1 promoter, suggesting their role in both the development of diabetic retinopathy and the metabolic memory phenomenon.

Hyperglycemia as a risk factor for cancer progression

As the prevalence of diabetes mellitus is substantially increasing worldwide, associated diseases such as renal failure, cardiovascular diseases, fatty liver, and cancers have also increased. A number of cancers such as pancreatic, liver, breast, and female reproductive cancers have shown an increased prevalence and a higher mortality rate in diabetic patients compared to healthy subjects. Thus, this suggests an association between diabetes, especially type 2 diabetes and cancer incidence and progression. Recent studies have suggested that hyperinsulinemia, chronic inflammation and hyperglycemia, all frequently seen in diabetics, may lead to increased tumor growth; the underlying molecular mechanisms of this association are not fully understood. In particular, chronic hyperglycemic episodes could serve as a direct or indirect mediator of the increase in tumor cell growth. Here, we will discuss our current understanding how hyperglycemia and cancer risk may be linked, and what the implications are for the treatment of diabetic cancer patients.

Hepatic FoxO1 acetylation is involved in oleanolic acid-induced memory of glycemic control: novel findings from Study 2

Our recent study (referred as Study 1) showed that the triterpenoid oleanolic acid (OA) was able to produce a sustained correction of hyperglycemia beyond treatment period in type 2 diabetes (T2D) mice with liver as a responsible site. To follow up the previous observations, the present study (referred as Study 2) investigated the possible role of acetylation of FoxO1 and associated events in this therapeutic memory by characterizing the pathways regulating the acetylation status during and post-OA treatments. OA treatment (100 mg/kg/day for 4 weeks, during OA treatment) reduced hyperglycemia in T2D mice by ∼87% and this effect was largely (∼70%) maintained even 4 weeks after the cessation of OA administration (post-OA treatment). During OA treatment, the acetylation and phosphorylation of FoxO1 were markedly increased (1.5 to 2.5-fold) while G6Pase expression was suppressed by ∼80%. Consistent with this, OA treatment reversed pyruvate intolerance in high-fat fed mice. Histone acetyltransferase 1 (HAT1) content was increased (>50%) and histone deacetylases (HDACs) 4 and 5 (not HDAC1) were reduced by 30–50%. The OA-induced changes in FoxO1, G6Pase, HAT1 and HDACs persisted during the post-OA treatment period when the increased phosphorylation of AMPK, SIRT1 content and reduced liver triglyceride had subsided. These results confirmed the ability of OA to control hyperglycemia far beyond treatment period in T2D mice. Most importantly, in the present study we demonstrated acetylation of FoxO1 in the liver is involved in OA-induced memory for the control of hyperglycemia. Our novel findings suggest that acetylation of the key regulatory proteins of hepatic gluconeogenesis is a plausible mechanism by the triterpenoid to achieve a sustained glycemic control for T2D.

Targeting cellular drivers and counter-regulators of hyperglycaemia- and transforming growth factor-β1-associated profibrotic responses in diabetic kidney disease

Diabetic kidney disease occurs in >30% of patients with type 2 diabetes mellitus and is characterized at source by a maladaptive response in the renal parenchyma to exposure to a glucotoxic-lipotoxic diabetic milieu that courses coincident with hypertension. The consequence of these maladaptive responses is progressive renal injury, which is exacerbated by the development of a chronic inflammatory infiltrate associated with the development of tubulointerstitial fibrosis. The evolution of tubulointerstitial fibrosis is correlated with the loss of functional renal mass and descent towards renal failure. Transforming growth factor-β1 (TGF-β1) is a recognized mediator of the profibrotic response of mesangial cells and renal tubular epithelial cells to hyperglycaemia. While euglycaemia remains the goal in the treatment of type 2 diabetes mellitus, the prevention, arrest and reversal of microvascular complications, such as diabetic kidney disease, may be assisted by pharmacological modulation of the effectors of glucotoxicity, such as TGF-β1. This review focuses on describing how, through reductionist in vitro experimentation focusing on TGF-β1-related responses to hyperglycaemia, we have identified induced in high glucose-1 (IHG-1), induced in high glucose-2 (IHG-2/Grem1) and the lipoxin-inducible microRNA let-7c as potential targets for harnessing new therapeutic approaches to limit the bioactivity of TGF-β1 in diabetic kidney disease.

Influence of Egr-1 in cardiac tissue-derived mesenchymal stem cells in response to glucose variations

Mesenchymal stem cells (MSCs) represent a promising cell population for cell therapy and regenerative medicine applications. However, how variations in glucose are perceived by MSC pool is still unclear. Since, glucose metabolism is cell type and tissue dependent, this must be considered when MSCs are derived from alternative sources such as the heart. The zinc finger transcription factor Egr-1 is an important early response gene, likely to play a key role in the glucose-induced response. Our aim was to investigate how short-term changes in in vitro glucose concentrations affect multipotent cardiac tissue-derived MSCs (cMSCs) in a mouse model of Egr-1 KO (Egr-1^−/−). Results showed that loss of Egr-1 does not significantly influence cMSC proliferation. In contrast, responses to glucose variations were observed in wt but not in Egr-1^−/− cMSCs by clonogenic assay. Phenotype analysis by RT-PCR showed that cMSCs Egr-1^−/− lost the ability to regulate the glucose transporters GLUT-1 and GLUT-4 and, as expected, the Egr-1 target genes VEGF, TGFβ-1, and p300. Acetylated protein levels of H3 histone were impaired in Egr-1^−/− compared to wt cMSCs. We propose that Egr-1 acts as immediate glucose biological sensor in cMSCs after a short period of stimuli, likely inducing epigenetic modifications.

Predictive factors of diabetic complications: a possible link between family history of diabetes and diabetic retinopathy

BACKGROUND

The aim of this study was assessment of predictive factors of diabetic retinopathy.

METHODS

A cross-sectional study was designed by recruiting 1228 type 2 diabetic patients from a diabetes referral clinic over a six-month period (from July to December, 2012). Diabetes risk factors, complications, laboratory results have been recorded.

RESULTS

Of the 1228 diabetic patients (54% women, mean age 58.48 ± 9.94 years), prevalence of diabetes retinopathy was 26.6%. There were significant associations between retinopathy and family history of diabetes (p = 0.04), hypertension (p = 0.0001), diabetic duration (p = 0.0001), poor glycemic control (p = 0.0001) and age of onset of diabetes (p = 0.0001). However, no significant associations were found between retinopathy with dyslipidemia and obesity. In logistic regression model, poor glycemic control (p = 0.014), hypertension (p = 0.0001), duration of diabetes (p = 0.0001) and family history of diabetes (p = 0.012) independently predicted retinopathy after adjustment for age and sex.

CONCLUSIONS

Diabetic complications are resulting from an interaction from genes and environmental factors. A family history of diabetes is pointing toward a possible genetic and epigenetic basis for diabetic retinopathy. Our findings suggest the role of epigenetic modifications and metabolic memory in diabetic retinopathy in subjects with family history of diabetes.

Comparison of brachial artery flow-mediated dilation in youth with type 1 and type 2 diabetes mellitus

Aims/Introduction

Brachial artery flow‐mediated dilation (FMD) is a method of evaluating the function of vascular endothelial cells and is utilized for early diagnosis of atherosclerotic diseases. Only a few studies evaluated the risks for major vascular complications in youth with type 1 and 2 diabetes mellitus from the aspect of the early development of atherosclerosis. We studied whether there is a difference in vascular endothelial cell function between youth with type 1 and 2 diabetes mellitus.

Materials and Methods

We assessed %FMD of 24 patients with type 1 diabetes mellitus and 27 patients with type 2 diabetes mellitus aged 12–20 years along with glycated hemoglobin, lipid metabolism markers such as triglycerides, and inflammatory biomarkers such as total adiponectin levels in adolescent patients with type 1 or 2 diabetes mellitus. The significance of the difference in each factor between the type 1 and type 2 diabetes groups was assessed using Student's t‐test.

Results

The %FMD was significantly lower in patients with type 2 diabetes. The body mass index and blood pressure were significantly higher, and total and high‐molecular‐weight adiponectin levels were significantly lower in patients with type 2 diabetes. %FMD significantly correlated with systolic blood pressure.

Conclusions

The results suggest that youth with type 2 diabetes have more advanced damage of the vascular endothelium and therefore are at higher risk for major vascular complications. Therefore, monitoring the progression of atherosclerosis would also be beneficial in youth with diabetes mellitus, and measurement of FMD could be further warranted.

Stiffness memory of EA.hy926 endothelial cells in response to chronic hyperglycemia

Background

Glycemic memory of endothelial cells is an effect of long-lasting hyperglycemia and is a cause of various diabetics complications, that arises despite of the treatment targeted towards returning low glucose level in blood system. On the other hand, endothelial dysfunction, which is believed to be a main cause of cardiovascular complications, is exhibited in the changes of mechanical properties of cells. Although formation of the glycemic memory was widely investigated, its impact on the mechanical properties of endothelial cells has not been studied yet.

Methods

In this study, nanoindentaion with a tip of an atomic force microscope was used to probe the long-term changes (through 26 passages, c.a. 80 days) in mechanical properties of EA.hy926 endothelial cells cultured in hyperglycemic conditions. As a complementary method, alterations in the structure of actin cytoskeleton were visualized by fluorescent staining of F-actin.

Results

We observed a gradual stiffening of the cells up to 20th passage for cells cultured in high glucose (25 mM). Fluorescence imaging has revealed that this behavior resulted from systematic remodeling of the actin cytoskeleton. In further passages, a drop in stiffness had occurred. The most interesting finding was recorded for cells transferred after 14 passages from high glucose to normal glucose conditions (5mM). After the transfer, the initial drop in stiffness was followed by a return of the cell stiffness to the value previously observed for cells cultured constantly in high glucose

Conclusions

Our results indicate that glycemic memory causes irreversible changes in stiffness of endothelial cells. The formation of the observed “stiffness memory” could be important in the context of vascular complications which develop despite the normalization of the glucose level.

Dietary alleviation of maternal obesity and diabetes: increased resistance to diet-induced obesity transcriptional and epigenetic signatures

According to the developmental origins of health and diseases (DOHaD), and in line with the findings of many studies, obesity during pregnancy is clearly a threat to the health and well-being of the offspring, later in adulthood. We previously showed that 20% of male and female inbred mice can cope with the obesogenic effects of a high-fat diet (HFD) for 20 weeks after weaning, remaining lean. However the feeding of a control diet (CD) to DIO mice during the periconceptional/gestation/lactation period led to a pronounced sex-specific shift (17% to 43%) from susceptibility to resistance to HFD, in the female offspring only. Our aim in this study was to determine how, in the context of maternal obesity and T2D, a CD could increase resistance on female fetuses. Transcriptional analyses were carried out with a custom-built mouse liver microarray and by quantitative RT-PCR for muscle and adipose tissue. Both global DNA methylation and levels of pertinent histone marks were assessed by LUMA and western blotting, and the expression of 15 relevant genes encoding chromatin-modifying enzymes was analyzed in tissues presenting global epigenetic changes. Resistance was associated with an enhancement of hepatic pathways protecting against steatosis, the unexpected upregulation of neurotransmission-related genes and the modulation of a vast imprinted gene network. Adipose tissue displayed a pronounced dysregulation of gene expression, with an upregulation of genes involved in lipid storage and adipocyte hypertrophy or hyperplasia in obese mice born to lean and obese mothers, respectively. Global DNA methylation, several histone marks and key epigenetic regulators were also altered. Whether they were themselves lean (resistant) or obese (sensitive), the offspring of lean and obese mice clearly differed in terms of several metabolic features and epigenetic marks suggesting that the effects of a HFD depend on the leanness or obesity of the mother.

Hyperglycemia and vascular metabolic memory: truth or fiction?

Prevention of long-term complications remains the main challenge in the treatment of diabetes. A strong relationship between glucose control and development of complications is apparent in all epidemiologic studies. Yet, intervention trials have yielded questionable results, particularly when intensive treatment was introduced in patients with long-standing diabetes. It has been postulated that in these subjects, prior exposure to chronic hyperglycemia may have generated a negative "metabolic memory," preventing full exertion of the beneficial effects of any subsequent improvement of glucose control. This phenomenon has been replicated in animal models and it recognizes a molecular basis in the role of oxidative stress, advanced glycation processes, and epigenetic mechanisms accounting for self-perpetuating modifications of gene expression. Conversely, early intervention in both type 1 and type 2 diabetes has proven that good glycemic control reduces the risk of development and progression of complications with a beneficial effect that extends well beyond the duration of near-normoglycemia. This has brought up the concept of "metabolic legacy," an advantage handed down by early and effective implementation of treatments designed to reduce blood glucose levels as safely as possible along with multifactorial intervention of all cardiovascular risk factors. The evidence, nature, and clinical implication of these concepts are reviewed.

Impact of high glucose and proteasome inhibitor MG132 on histone H2A and H2B ubiquitination in rat glomerular mesangial cells

BACKGROUND

Hyperglycemia plays a pivotal role in the development of diabetic nephropathy (DN) and may be related to epigenetic metabolic memory. One of the most crucial epigenetic mechanisms is histone modification, which is associated with the expression of a fibrosis factor in vascular injury. Aim .In this study, we investigated the ubiquitination of histones H2A and H2B to explore the epigenetic mechanisms of DN.

MATERIALS AND METHODS

The GMCs were cultured as follows: normal group, high glucose group, mannitol group, and intervention group. After 12 hr, 24 hr, and 48 hr, histones ubiquitination, transforming growth factor-β (TGF-β), and fibronectin (FN) were measured using WB, RT-PCR, and IF.

RESULT

High glucose can induce the upregulation of FN. H2A ubiquitination in GMCs increased in high glucose group (P < 0.01), whereas it decreased significantly in intervention group (P < 0.05). In contrast, H2B ubiquitination decreased with an increasing concentration of glucose, but it was recovered in the intervention group (P < 0.05). Expression of TGF-β changed in response to abnormal histone ubiquitination.

CONCLUSIONS

The high glucose may induce H2A ubiquitination and reduce H2B ubiquitination in GMCs. The changes of histone ubiquitination may be due in part to DN by activating TGF-β signaling pathway.

Modification of RelA by O-linked N-acetylglucosamine links glucose metabolism to NF-κB acetylation and transcription

The molecular mechanisms linking glucose metabolism with active transcription remain undercharacterized in mammalian cells. Using nuclear factor-κB (NF-κB) as a glucose-responsive transcription factor, we show that cells use the hexosamine biosynthesis pathway and O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) to potentiate gene expression in response to tumor necrosis factor (TNF) or etoposide. Chromatin immunoprecipitation assays demonstrate that, upon induction, OGT localizes to NF-κB-regulated promoters to enhance RelA acetylation. Knockdown of OGT abolishes p300-mediated acetylation of RelA on K310, a posttranslational mark required for full NF-κB transcription. Mapping studies reveal T305 as an important residue required for attachment of the O-GlcNAc moiety on RelA. Furthermore, p300 fails to acetylate a full-length RelA(T305A) mutant, linking O-GlcNAc and acetylation events on NF-κB. Reconstitution of RelA null cells with the RelA(T305A) mutant illustrates the importance of this residue for NF-κB-dependent gene expression and cell survival. Our work provides evidence for a unique regulation where attachment of the O-GlcNAc moiety to RelA potentiates p300 acetylation and NF-κB transcription.