Epigenetics and Cardiovascular Disease in Diabetes

Dysregulation of long non-coding RNA gene expression pathways in monocytes of type 2 diabetes patients with cardiovascular disease

BACKGROUND

Monocytes play a central role in the pathophysiology of cardiovascular complications in type 2 diabetes (T2D) patients through different mechanisms. We investigated diabetes-induced changes in lncRNA genes from T2D patients with cardiovascular disease (CVD), long-duration diabetes, and poor glycemic control.

METHODS

We performed paired-end RNA sequencing of monocytes from 37 non-diabetes controls and 120 patients with T2D, of whom 86 had either macro or microvascular disease or both. Monocytes were sorted from peripheral blood using flow cytometry; their RNA was purified and sequenced. Alignments and gene counts were obtained with STAR to reference GRCh38 using Gencode (v41) annotations followed by batch correction with CombatSeq. Differential expression analysis was performed with EdgeR and pathway analysis with IPA software focusing on differentially expressed genes (DEGs) with a p-value < 0.05. Additionally, differential co-expression analysis was done with csdR to identify lncRNAs highly associated with diabetes-related expression networks with network centrality scores computed with Igraph and network visualization with Cytoscape.

RESULTS

Comparing T2D vs. non-T2D, we found two significantly upregulated lncRNAs (ENSG00000287255, FDR = 0.017 and ENSG00000289424, FDR = 0.048) and one significantly downregulated lncRNA (ENSG00000276603, FDR = 0.017). Pathway analysis on DEGs revealed networks affecting cellular movement, growth, and development. Co-expression analysis revealed ENSG00000225822 (UBXN7-AS1) as the highest-scoring diabetes network-associated lncRNA. Analysis within T2D patients and CVD revealed one lncRNA upregulated in monocytes from patients with microvascular disease without clinically documented macrovascular disease. (ENSG00000261654, FDR = 0.046). Pathway analysis revealed DEGs involved in networks affecting metabolic and cardiovascular pathologies. Co-expression analysis identified lncRNAs strongly associated with diabetes networks, including ENSG0000028654, ENSG00000261326 (LINC01355), ENSG00000260135 (MMP2-AS1), ENSG00000262097, and ENSG00000241560 (ZBTB20-AS1) when we combined the results from all patients with CVD. Similarly, we identified from co-expression analysis of diabetes patients with a duration ≥ 10 years vs. <10 years two lncRNAs: ENSG00000269019 (HOMER3-AS10) and ENSG00000212719 (LINC02693). The comparison of patients with good vs. poor glycemic control also identified two lncRNAs: ENSG00000245164 (LINC00861) and ENSG00000286313.

CONCLUSION

We identified dysregulated diabetes-related genes and pathways in monocytes of diabetes patients with cardiovascular complications, including lncRNA genes of unknown function strongly associated with networks of known diabetes genes.

Metabolic memory: mechanisms and diseases

Metabolic diseases and their complications impose health and economic burdens worldwide. Evidence from past experimental studies and clinical trials suggests our body may have the ability to remember the past metabolic environment, such as hyperglycemia or hyperlipidemia, thus leading to chronic inflammatory disorders and other diseases even after the elimination of these metabolic environments. The long-term effects of that aberrant metabolism on the body have been summarized as metabolic memory and are found to assume a crucial role in states of health and disease. Multiple molecular mechanisms collectively participate in metabolic memory management, resulting in different cellular alterations as well as tissue and organ dysfunctions, culminating in disease progression and even affecting offspring. The elucidation and expansion of the concept of metabolic memory provides more comprehensive insight into pathogenic mechanisms underlying metabolic diseases and complications and promises to be a new target in disease detection and management. Here, we retrace the history of relevant research on metabolic memory and summarize its salient characteristics. We provide a detailed discussion of the mechanisms by which metabolic memory may be involved in disease development at molecular, cellular, and organ levels, with emphasis on the impact of epigenetic modulations. Finally, we present some of the pivotal findings arguing in favor of targeting metabolic memory to develop therapeutic strategies for metabolic diseases and provide the latest reflections on the consequences of metabolic memory as well as their implications for human health and diseases.

Modeling diabetic endothelial dysfunction with patient-specific induced pluripotent stem cells

Diabetes is a known risk factor for various cardiovascular complications, mediated by endothelial dysfunction. Despite the high prevalence of this metabolic disorder, there is a lack of in vitro models that recapitulate the complexity of genetic and environmental factors associated with diabetic endothelial dysfunction. Here, we utilized human induced pluripotent stem cell (iPSC)-derived endothelial cells (ECs) to develop in vitro models of diabetic endothelial dysfunction. We found that the diabetic phenotype was recapitulated in diabetic patient-derived iPSC-ECs, even in the absence of a diabetogenic environment. Subsequent exposure to culture conditions that mimic the diabetic clinical chemistry induced a diabetic phenotype in healthy iPSC-ECs but did not affect the already dysfunctional diabetic iPSC-ECs. RNA-seq analysis revealed extensive transcriptome-wide differences between cells derived from healthy individuals and diabetic patients. The in vitro disease models were used as a screening platform which identified angiotensin receptor blockers (ARBs) that improved endothelial function in vitro for each patient. In summary, we present in vitro models of diabetic endothelial dysfunction using iPSC technology, taking into account the complexity of genetic and environmental factors in the metabolic disorder. Our study provides novel insights into the pathophysiology of diabetic endothelial dysfunction and highlights the potential of iPSC-based models for drug discovery and personalized medicine.

DNA methylation profiling reveals novel pathway implicated in cardiovascular diseases of diabetes

OBJECTIVE

Epigenetics was reported to mediate the effects of environmental risk factors on disease pathogenesis. We intend to unleash the role of DNA methylation modification in the pathological process of cardiovascular diseases in diabetes.

METHODS

We screened differentially methylated genes by methylated DNA immunoprecipitation chip (MeDIP-chip) among the enrolled participants. In addition, methylation-specific PCR (MSP) and gene expression validation in peripheral blood of participants were utilized to validate the DNA microarray findings.

RESULTS

Several aberrantly methylated genes have been explored, including phospholipase C beta 1 (PLCB1), cam kinase I delta (CAMK1D), and dopamine receptor D5 (DRD5), which participated in the calcium signaling pathway. Meanwhile, vascular endothelial growth factor B (VEGFB), placental growth factor (PLGF), fatty acid transport protein 3 (FATP3), coagulation factor II, thrombin receptor (F2R), and fatty acid transport protein 4 (FATP4) which participated in vascular endothelial growth factor receptor (VEGFR) signaling pathway were also found. After MSP and gene expression validation in peripheral blood of participants, PLCB1, PLGF, FATP4, and VEGFB were corroborated.

CONCLUSION

This study revealed that the hypomethylation of VEGFB, PLGF, PLCB1, and FATP4 might be the potential biomarkers. Besides, VEGFR signaling pathway regulated by DNA methylation might play a role in the cardiovascular diseases' pathogenesis of diabetes.

DNA methylation predicts the outcome of COVID-19 patients with acute respiratory distress syndrome

BACKGROUND

COVID-19 infections could be complicated by acute respiratory distress syndrome (ARDS), increasing mortality risk. We sought to assess the methylome of peripheral blood mononuclear cells in COVID-19 with ARDS.

METHODS

We recruited 100 COVID-19 patients with ARDS under mechanical ventilation and 33 non-COVID-19 controls between April and July 2020. COVID-19 patients were followed at four time points for 60 days. DNA methylation and immune cell populations were measured at each time point. A multivariate cox proportional risk regression analysis was conducted to identify predictive signatures according to survival.

RESULTS

The comparison of COVID-19 to controls at inclusion revealed the presence of a 14.4% difference in promoter-associated CpGs in genes that control immune-related pathways such as interferon-gamma and interferon-alpha responses. On day 60, 24% of patients died. The inter-comparison of baseline DNA methylation to the last recorded time point in both COVID-19 groups or the intra-comparison between inclusion and the end of follow-up in every group showed that most changes occurred as the disease progressed, mainly in the AIM gene, which is associated with an intensified immune response in those who recovered. The multivariate Cox proportional risk regression analysis showed that higher methylation of the "Apoptotic execution Pathway" genes (ROC1, ZNF789, and H1F0) at inclusion increases mortality risk by over twofold.

CONCLUSION

We observed an epigenetic signature of immune-related genes in COVID-19 patients with ARDS. Further, Hypermethylation of the apoptotic execution pathway genes predicts the outcome.

TRIAL REGISTRATION

IMRPOVIE study, NCT04473131.

Altered Circulating microRNAs in Patients with Diabetic Neuropathy and Corneal Nerve Loss: A Pilot Study

An alteration in circulating miRNAs may have important diagnostic and therapeutic relevance in diabetic neuropathy. Patients with type 2 diabetes mellitus (T2DM) underwent an assessment of neuropathic symptoms using Douleur Neuropathique 4 (DN4), the vibration perception threshold (VPT) using a Neurothesiometer, sudomotor function using the Sudoscan, corneal nerve morphology using corneal confocal microscopy (CCM) and circulating miRNAs using high-throughput miRNA expression profiling. Patients with T2DM, with (n = 9) and without (n = 7) significant corneal nerve loss were comparable in age, gender, diabetes duration, BMI, HbA1c, eGFR, blood pressure, and lipid profile. The VPT was significantly higher (p < 0.05), and electrochemical skin conductance (p < 0.05), corneal nerve fiber density (p = 0.001), corneal nerve branch density (p = 0.013), and corneal nerve fiber length (p < 0.001) were significantly lower in T2DM patients with corneal nerve loss compared to those without corneal nerve loss. Following a q-PCR-based analysis of total plasma microRNAs, we found that miR-92b-3p (p = 0.008) was significantly downregulated, while miR-22-3p (p = 0.0001) was significantly upregulated in T2DM patients with corneal nerve loss. A network analysis revealed that these miRNAs regulate axonal guidance and neuroinflammation genes. These data support the need for more extensive studies to better understand the role of dysregulated miRNAs’ in diabetic neuropathy.

Long-term cardiometabolic consequences among adolescent offspring born to women with type1 diabetes

AIM

The aim of this study was to compare cardiometabolic measures between adolescents born to women with and without type1diabetes.

METHODS

In this cross-sectional study, 103 adolescents (51 males) aged 14-19 years, born to women with type1diabetes were enrolled in the study. Body mass index, blood pressure, urine microalbumin to creatinine ratio, hemoglobin A1c, serum urate, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, and estimated glomerular filtration rate (eGFR) were measured in all. The results were compared with 98 adolescents born to non-diabetic women.

RESULTS

In multiple linear regression models, adolescent offspring of women with type 1 diabetes had significantly higher blood pressure (Odds ratio [OR] 2·45; 95% Confidence interval [CI] 2.1-2.8, hypertension (OR 2.52; 95% CI 1.99-3.01), body mass index (OR 2.22; 95% CI: 1.76-2.69), elevated total cholesterol (OR 1.5; 95% CI 0.2-2.9), low-density lipoprotein cholesterol (OR·33; 95% CI 1.06-1.64), triglyceride (OR 1.34; 95% CI: 1.05-1.70), eGFR (OR 0.96 ;95% CI 0.81-1.11) and microlabuminuria (OR 1.1; 95% CI: 0.87-1.12) compared to offspring of women without diabetes.

CONCLUSION

The study demonstrates a strong correlation between maternal exposure to type1diabetes and higher risk of developing obesity, hypertension, dyslipidemia, eGFR, and microalbumiuria in the adolescent offspring.

Research Progress on Epigenetics of Diabetic Cardiomyopathy in Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is characterized by diastolic relaxation abnormalities in its initial stages and by clinical heart failure (HF) without dyslipidemia, hypertension, and coronary artery disease in its last stages. DCM contributes to the high mortality and morbidity rates observed in diabetic populations. Diabetes is a polygenic, heritable, and complex condition that is exacerbated by environmental factors. Recent studies have demonstrated that epigenetics directly or indirectly contribute to pathogenesis. While epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, have been recognized as key players in the pathogenesis of DCM, some of their impacts remain not well understood. Furthering our understanding of the roles played by epigenetics in DCM will provide novel avenues for DCM therapeutics and prevention strategies.

Methylglyoxal stimulates endoplasmic reticulum stress in vascular smooth muscle cells

Methylglyoxal (MGO) is considered responsible for the detrimental effects of high blood glucose. MGO is produced as a by-product of the glycolysis pathway. While the glyoxalase system removes it, the system fails in people with diabetes. MGO concentration is detected as elevated in these patients. Endoplasmic reticulum (ER) stress may play a role in atherosclerosis progression and vascular diseases. If ER stress persists, it may result in apoptosis of the cell. As a result, stabilized plaque structure by these cells may be ruptured and cause a stroke. This study aimed to investigate whether MGO can induce ER stress and apoptosis in vascular smooth muscle cells (VSMCs). Also, the effects of aminoguanidine hydrochloride (AGH), 4-phenylbutyric acid (4-PBA), and tauroursodeoxycholic acid (TUDCA) were scrutinized to relieve ER stress. VSMCs were isolated from rat aorta and cultured primary. PERK phosphorylation, IRE1α, ATF6, BiP (Grp78), and CHOP expressions were detected by the western blot technique. A caspase-3 assay kit measured the apoptosis. MGO could stimulate the main three ER stress pathways, PERK phosphorylation, IRE1α, and ATF6 expressions in a time- and concentration-dependent manner. Furthermore, AGH, 4-PBA, and TUDCA alleviated MGO-induced ER stress. However, we detected neither an increase in CHOP expression nor apoptosis in VSMCs. This study shows that MGO induces ER stress even at low concentrations in VSMCs. The impaired glyoxalase system may cause MGO accumulation and result in persisted ER stress. Supposing that ER stress is not mitigated, this table might be finalized in cell apoptosis, plaque rupture, and stroke.

Long noncoding RNAs: Potential therapeutic targets in cardiocerebrovascular diseases

Cardiocerebrovascular disease is a collective term for cardiovascular and cerebrovascular diseases. Because of the complex mechanisms involved in cardiocerebrovascular diseases, limited effective treatments have been developed. With advancements in precision medicine, studies have focused on long noncoding RNAs (lncRNAs) in cerebrovascular diseases. LncRNAs, which are over 200 nucleotides long, regulate gene expression at epigenetic, transcriptional, and post-transcriptional levels. Moreover, lncRNAs play pivotal roles in the progression of cardiocerebrovascular diseases. For example, recent studies suggested that abnormal expression of lncRNAs are closely related to the occurrence and progression of these diseases. LncRNAs regulate gene expression by specifically binding to mRNA to modulate disease progression, serving as biomarkers for the diagnosis and prognosis of cardiocerebrovascular diseases. In this review, we discuss the roles, mechanisms, and clinical value of lncRNAs in cardiocerebrovascular diseases, providing a new perspective for the diagnosis and treatment of the diseases.

Genome-Wide DNA Methylation and LncRNA-Associated DNA Methylation in Metformin-Treated and -Untreated Diabetes

Metformin, which is used as a first line treatment for type 2 diabetes mellitus (T2DM), has been shown to affect epigenetic patterns. In this study, we investigated the DNA methylation and potential lncRNA modifications in metformin-treated and newly diagnosed adults with T2DM. Genome-wide DNA methylation and lncRNA analysis were performed from the peripheral blood of 12 screen-detected and 12 metformin-treated T2DM individuals followed by gene ontology (GO) and KEGG pathway analysis. Differentially methylated regions (DMRs) observed showed 22 hypermethylated and 11 hypomethylated DMRs between individuals on metformin compared to screen-detected subjects. Amongst the hypomethylated DMR regions were the SLC gene family, specifically, SLC25A35 and SLC28A1. Fifty-seven lncRNA-associated DNA methylation regions included the mitochondrial ATP synthase-coupling factor 6 (ATP5J). Functional gene mapping and pathway analysis identified regions in the axon initial segment (AIS), node of Ranvier, cell periphery, cleavage furrow, cell surface furrow, and stress fiber. In conclusion, our study has identified a number of DMRs and lncRNA-associated DNA methylation regions in metformin-treated T2DM that are potential targets for therapeutic monitoring in patients with diabetes.

Whole-methylome analysis of circulating monocytes in acute diabetic Charcot foot reveals differentially methylated genes involved in the formation of osteoclasts

AIM

To assess whether DNA methylation of monocytes play a role in the development of acute diabetic Charcot foot (CF).

PATIENTS & METHODS

We studied the whole methylome (WM) of circulating monocytes in 18 patients with Type 2 diabetes (T2D) and acute CF, 18 T2D patients with equivalent neuropathy and 18 T2D patients without neuropathy, using the enhanced reduced representation bisulfite sequencing technique.

RESULTS & CONCLUSION

WM analysis demonstrated that CF monocytes are differentially methylated compared with non-CF monocytes, in both CpG-site and gene-mapped analysis approaches. Among the methylated genes, several are involved in the migration process during monocyte differentiation into osteoclasts or are indirectly involved through the regulation of inflammatory pathways. Finally, we demonstrated an association between methylation and gene expression in cis- and trans-association.

Immunoregulatory Siglec ligands are abundant in human and mouse aorta and are up-regulated by high glucose

AIM

Inflammation is a driving force in development of atherosclerosis, and hyperglycemia is a significant risk factor for angiopathy. Siglec-9, expressed on human neutrophils and macrophages, engages specific glycan ligands on tissues to diminish ongoing inflammation.

MATERIALS AND METHOD

Siglec-9 ligands on human aorta were characterized and the effects of high glucose exposure on the expression of ligands for Siglec-9 on human umbilical vein endothelial cells (HUV-EC-C) in vitro and ligands for the comparable siglec (Siglec-E) on mouse aorta in vivo were studied.

KEY FINDINGS

Siglec-9 ligands were expressed broadly on human aorta, as well as on HUV-EC-C. Siglec-9 ligands on HUV-EC-C were sharply up-regulated under high glucose exposure in vitro, as were Siglec-E ligands on the aortas of hyperglycemic mice. Exposure of HUV-EC-C to high-glucose resulted in consistent inhibitory changes in co-cultured macrophages including increased apoptosis and decreased phagocytosis. Control of Siglec-9 ligand expression on HUV-EC-C was downstream of changes in an enzyme involved in their biosynthesis, UDP-galactose-4-epimerase (GALE) and increased cellular N-acetylgalactosamine. The alteration of GALE was associated with the regulatory microRNA hsa-let-7f.

SIGNIFICANCE

We conclude that exposure to high-glucose results in up-regulation of immune inhibitory Siglec-9 sialoglycan ligands on aorta and HUV-EC-C cells downstream of altered GALE and GalNAc expression, resulting in up-regulation of apoptosis and decrease of phagocytic activity of macrophages. Changes in Siglec-9 sialoglycan ligand expression on vascular endothelial cells may be a natural response to the initial steps of atherosclerosis and might be a potential target to regulate inflammation in diabetic angiopathy.

Remodeling of Retinal Architecture in Diabetic Retinopathy: Disruption of Ocular Physiology and Visual Functions by Inflammatory Gene Products and Pyroptosis

Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells' redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.

Histones and heart failure in diabetes

Although heart failure is now accepted as being a major long-term complication of diabetes, many of the recent advances in our understanding of the pathobiology of diabetes complications have come about through the study of more traditional microvascular or macrovascular diseases. This has been the case, for example, in the evolving field of the epigenetics of diabetes complications and, in particular, the post-translational modification of histone proteins. However, histone modifications also occur in human heart failure and their perturbation also occurs in diabetic hearts. Here, we review the principal histone modifications and their enzymatic writers and erasers that have been studied to date; we discuss what is currently known about their roles in heart failure and in the diabetic heart; we draw on lessons learned from the studies of microvascular and macrovascular complications; and we speculate that therapeutically manipulating histone modifications may alter the natural history of heart failure in diabetes.

Differentially expressed circulating microRNAs in the development of acute diabetic Charcot foot

Aim:

Charcot foot (CF) is a rare complication of Type 2 diabetes (T2D).

Materials & methods:

We assessed circulating miRNAs in 17 patients with T2D and acute CF (G1), 17 patients with T2D (G2) and equivalent neuropathy and 17 patients with T2D without neuropathy (G3) using the high-throughput miRNA expression profiling.

Results:

51 significantly deregulated miRNAs were identified in G1 versus G2, 37 in G1 versus G3 and 64 in G2 versus G3. Furthermore, we demonstrated that 16 miRNAs differentially expressed between G1 versus G2 could be involved in osteoclastic differentiation. Among them, eight are key factors involved in CF pathophysiology.

Conclusion:

Our data reveal that CF patients exhibit an altered expression profile of circulating miRNAs.

Therapeutic efficacy of cyclosporin A against spinal cord injury in rats with hyperglycemia

The present study aimed to explore the therapeutic effects of cyclosporin A (CsA) on spinal cord injury (SCI) in rats with hyperglycemia and to identify a novel potential method to treat SCI in the presence of hyperglycemia. Female Sprague‑Dawley (SD) rats were randomly allocated into four groups: Sham, SCI, SCI+hyperglycemia and SCI+hyperglycemia+CsA groups. Streptozotocin‑induced hyperglycemic SD rats and a weight‑drop contusion SCI model were established. The Basso, Beattie, Bresnahan scale and inclined plane test were used to evaluate the neurological function of the rats. Flow cytometric assay was performed to detect the apoptotic rates of cells in the spinal cord. ELISA and western blot analysis were performed to determine the levels of interleukin (IL)‑10, tumor necrosis factor (TNF)‑α, cyclophilin‑D (Cyp‑D) and apoptosis‑inducing factor (AIF). The results demonstrated that CsA significantly improved the neurological function of the SCI rats with hyperglycemia. CsA markedly reduced the number of apoptotic cells exaggerated by hyperglycemia in the spinal cord of the SCI rats. CsA significantly decreased the expression levels of IL‑10, TNF‑α, Cyp‑D and AIF in the spinal cord of the SCI rats. Overall, the present study revealed a significant role of CsA in the treatment of SCI in the presence of hyperglycemia by inhibiting the apoptosis of spinal cord cells.

Treponema denticola increases MMP-2 expression and activation in the periodontium via reversible DNA and histone modifications

Host-derived matrix metalloproteinases (MMPs) and bacterial proteases mediate destruction of extracellular matrices and supporting alveolar bone in periodontitis. The Treponema denticola dentilisin protease induces MMP-2 expression and activation in periodontal ligament (PDL) cells, and dentilisin-mediated activation of pro-MMP-2 is required for cellular fibronectin degradation. Here, we report that T. denticola regulates MMP-2 expression through epigenetic modifications in the periodontium. PDL cells were treated with epigenetic enzyme inhibitors before or after T. denticola challenge. Fibronectin fragmentation, MMP-2 expression, and activation were assessed by immunoblot, zymography, and qRT-PCR, respectively. Chromatin modification enzyme expression in T. denticola-challenged PDL cells and periodontal tissues were evaluated using gene arrays. Several classes of epigenetic enzymes showed significant alterations in transcription in diseased tissue and T. denticola-challenged PDL cells. T. denticola-mediated MMP-2 expression and activation were significantly reduced in PDL cells treated with inhibitors of aurora kinases and histone deacetylases. In contrast, DNA methyltransferase inhibitors had little effect, and inhibitors of histone acetyltransferases, methyltransferases, and demethylases exacerbated T. denticola-mediated MMP-2 expression and activation. Chronic epigenetic changes in periodontal tissues mediated by T. denticola or other oral microbes may contribute to the limited success of conventional treatment of chronic periodontitis and may be amenable to therapeutic reversal.

Circulating microparticles in acute diabetic Charcot foot exhibit a high content of inflammatory cytokines, and support monocyte-to-osteoclast cell induction

Circulating microparticles (MPs) are major mediators in cardiovascular complications of type 2 diabetes (T2D); however, their contribution to Charcot foot (CF) disease is not known. Here, we purified and assessed the origin, concentration and content of circulating MPs from 33 individuals: 11 with T2D and acute CF, 11 T2D patients with equivalent neuropathy and 11 non-diabetic controls. First, we demonstrated that there were no differences in the distribution of MPs of endothelial, platelet origin among the 3 groups. However, MPs from leukocytes and monocytes origin were increased in CF patients. Moreover, we demonstrated that monocytes-derived MPs originated more frequently from intermediate and non-classical monocytes in CF patients. Five cytokines (G-CSF, GM-CSF, IL-1-ra, IL-2 and IL-16) were significantly increased in MPs from acute CF patients. Applying ingenuity pathways analysis, we found that those cytokines interacted well and induced the activation of pathways that are involved in osteoclast formation. Further, we treated THP-1 monocytes and monocytes sorted from healthy patients with CF-derived MPs during their differentiation into osteoclasts, which increased their differentiation into multinucleated osteoclast-like cells. Altogether, our study suggests that circulating MPs in CF disease have a high content of inflammatory cytokines and could increase osteoclast differentiation in vitro.

Genome-wide DNA methylome alterations in acute coronary syndrome

Acute coronary syndrome (ACS) is a common disease with high mortality and morbidity rates. The methylation status of blood DNA may serve as a potential early diagnosis and prevention biomarker for numerous diseases. The present study was designed to explore novel genome-wide aberrant DNA methylation patterns associated with ACS. The Infinium HumanMethylation450 assay was used to examine genome-wide DNA methylation profiles in 3 pairs of ACS and control group samples. Epigenome-wide DNA methylation, genomic distribution, Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. The results were confirmed using methylation-specific polymerase chain reaction (MSP) and Sequenom MassARRAY analyses in ACS, stable coronary artery disease (SCAD) and control samples. A total of 11,342 differentially methylated (DM) 5′-C-phosphate-G-3′ (CpG) sites were identified, including 8,865 hypomethylated and 2,477 hypermethylated CpG sites in the ACS group compared with the control samples. They varied in frequency across genomic compartments, but were particularly notable in gene bodies and shores. The results of GO term and KEGG pathway enrichment analyses revealed that the methylated genes were associated with certain biological processes and pathways. Despite the considerable variability in methylation data, the candidate selected possessed significant methylation alteration in mothers against decapentaplegic homolog 3 (SMAD3) transcription start site 155 (Chr1:67356838-Chr1:67356942). MSP analysis from 81 ACS samples, 74 SCAD samples and 53 healthy samples, and Sequenom MassARRAY analysis, confirmed that differential CpG methylation of SMAD3 was significantly corrected with the reference results of the HumanMethylation450 array. The data identified an ACS-specific DNA methylation profile with a large number of novel DM CpG sites, some of which may serve as candidate markers for the early diagnosis of ACS.

A Unified Pathophysiological Construct of Diabetes and its Complications

Advances in understanding diabetes mellitus (DM) through basic and clinical research have helped clarify and reunify a disease state fragmented into numerous etiologies and subtypes. It is now understood that a common pathophysiology drives the diabetic state throughout its natural history and across its varied clinical presentations, a pathophysiology involving metabolic insults, oxidative damage, and vicious cycles that aggravate and intensify organ dysfunction and damage. This new understanding of the disease requires that we revisit existing diagnostics and treatment approaches, which were built upon outmoded assumptions. 'The Common Pathophysiologic Origins of Diabetes Mellitus and its Complications Construct' is presented as a more accurate, foundational, and translatable construct of DM that helps make sense of the hitherto ambiguous findings of long-term outcome studies.

Host gene expression analysis in Sri Lankan melioidosis patients

BACKGROUND

Melioidosis is a life threatening infectious disease caused by the gram-negative bacillus Burkholderia pseudomallei predominantly found in southeast Asia and northern Australia. Studying the host transcription profiles in response to infection is crucial for understanding disease pathogenesis and correlates of disease severity, which may help improve therapeutic intervention and survival. The aim of this study was to analyze gene expression levels of human host factors in melioidosis patients and establish useful correlation with disease biomarkers, compared to healthy individuals and patients with sepsis caused by other pathogens.

METHODS

The study population consisted of 30 melioidosis cases, 10 healthy controls and 10 sepsis cases caused by other pathogens. Total RNA was extracted from peripheral blood mononuclear cells (PBMC's) of study subjects. Gene expression profiles of 25 gene targets including 19 immune response genes and 6 epigenetic factors were analyzed by real time quantitative polymerase chain reaction (RT-qPCR).

PRINCIPAL FINDINGS

Inflammatory response genes; TLR4, late onset inflammatory mediator HMGB1, genes associated with antigen presentation; MICB, PSMB2, PSMB8, PSME2, epigenetic regulators; DNMT3B, HDAC1, HDAC2 were significantly down regulated, whereas the anti-inflammatory gene; IL4 was up regulated in melioidosis patients compared to sepsis cases caused by other pathogens. Septicaemic melioidosis cases showed significant down regulation of IL8 compared to sepsis cases caused by other pathogens. HMGB1, MICB, PSMB8, PSMB2, PSME2, HDAC1, HDAC2 and DNMT3B showed consistent down regulation of gene expression in melioidosis patients compared to other sepsis infection, irrespective of comorbidities such as diabetes, duration of clinical symptoms and antibiotic treatment.

SIGNIFICANCE

Specific immune response genes and epigenetic regulators are differentially expressed among melioidosis patients and patients with sepsis caused by other pathogens. Therefore, these genes may serve as biomarkers for disease diagnosis to distinguish melioidosis from cases of sepsis due to other infections and therapeutic intervention for melioidosis.

Identical twins doubly exchanged at birth: a case report of genetic and environmental influences on the adult epigenome

AIM

Epigenetic comparisons within monozygotic twin pairs have enhanced our understanding of nongenetic mechanisms underlying disease etiology. We present epigenetic findings for a unique case of doubly exchanged Colombian male monozygotic twins raised in extremely different environments.

RESULTS

Using genome-wide DNA methylation data from cheek swabs from which blood-specific differentially methylated probes had been removed, the individuals grouped by shared genetics rather than shared environment, except for one twin who presented as an outlier. Closer inspection of DNA methylation differences within both reared-apart twin pairs revealed several genes and genetic pathways likely to be influenced by the rearing environment.

CONCLUSION

Together with our previous findings, we suggest that genetics, pre- and postnatal environments contribute to the epigenetic profile, although additional studies are needed to quantify these effects.

Epigenetic mechanisms in microbial members of the human microbiota: current knowledge and perspectives

The human microbiota and epigenetic processes have both been shown to play a crucial role in health and disease. However, there is extremely scarce information on epigenetic modulation of microbiota members except for a few pathogens. Mainly DNA adenine methylation has been described extensively in modulating the virulence of pathogenic bacteria in particular. It would thus appear likely that such mechanisms are widespread for most bacterial members of the microbiota. This review will present briefly the current knowledge on epigenetic processes in bacteria, give examples of known methylation processes in microbial members of the human microbiota and summarize the knowledge on regulation of host epigenetic processes by the human microbiota.

Epigenetics and obesity cardiomyopathy: From pathophysiology to prevention and management

Uncorrected obesity has been associated with cardiac hypertrophy and contractile dysfunction. Several mechanisms for this cardiomyopathy have been identified, including oxidative stress, autophagy, adrenergic and renin-angiotensin aldosterone overflow. Another process that may regulate effects of obesity is epigenetics, which refers to the heritable alterations in gene expression or cellular phenotype that are not encoded on the DNA sequence. Advances in epigenome profiling have greatly improved the understanding of the epigenome in obesity, where environmental exposures during early life result in an increased health risk later on in life. Several mechanisms, including histone modification, DNA methylation and non-coding RNAs, have been reported in obesity and can cause transcriptional suppression or activation, depending on the location within the gene, contributing to obesity-induced complications. Through epigenetic modifications, the fetus may be prone to detrimental insults, leading to cardiac sequelae later in life. Important links between epigenetics and obesity include nutrition, exercise, adiposity, inflammation, insulin sensitivity and hepatic steatosis. Genome-wide studies have identified altered DNA methylation patterns in pancreatic islets, skeletal muscle and adipose tissues from obese subjects compared with non-obese controls. In addition, aging and intrauterine environment are associated with differential DNA methylation. Given the intense research on the molecular mechanisms of the etiology of obesity and its complications, this review will provide insights into the current understanding of epigenetics and pharmacological and non-pharmacological (such as exercise) interventions targeting epigenetics as they relate to treatment of obesity and its complications. Particular focus will be on DNA methylation, histone modification and non-coding RNAs.