miR-33a modulates ABCA1 expression, cholesterol accumulation, and insulin secretion in pancreatic islets

Resveratrol Prevents Weight Gain, Counteracts Visceral Adipose Tissue Dysfunction, and Improves Hypothalamic Leptin Sensitivity in Diet-Induced Obese Rats

In obesity, increased adipocyte size is associated with metabolic complications, while elevated adipocyte numbers are considered a protective mechanism against metabolic disturbances. Adipose tissue dysfunction leads to decreased leptin sensitivity and disrupted energy balance regulation. Resveratrol (RSV), a bioactive compound known for potential health benefits, including obesity-related disorder prevention, has unclear modulatory effects on adipocyte dysfunction and leptin signaling in established obesity. This study investigated the impact of RSV on adiposity and hypothalamic leptin sensitivity in obesity. Rats were fed a cafeteria diet for 9 weeks and subsequently supplemented with different doses of RSV for 22 days. The 200 mg/kg RSV dose reduced leptin concentrations, body weight gain, and body fat mass in obese animals, while mitigating adipocyte hypertrophy and promoting adipocyte hyperplasia in the retroperitoneal fat depot. RSV also improved hypothalamic leptin sensitivity, shedding light on the molecular mechanisms underlying the benefits of RSV consumption for obesity-related disorders.

Crosstalk between microRNA and inflammation; critical regulator of diabetes

A growing body of evidence indicates that microRNAs (miRNAs may be used as biomarkers for the diagnosis, prognosis, and treatment of diabetes, given their changed expression profile as the disease progresses. There is growing interest in using individual miRNAs or whole miRNA clusters linked to diabetes as therapeutic targets because of their abnormal expression and functioning. In diabetes, miRNAs are also involved in inflammatory and immunological responses. Additionally, the inflammatory response controls the generation, processing, and stability of pre- or mature miRNAs and miRNA biogenesis. With a comprehensive grasp of molecular biological activities and the signaling axis, this review emphasizes the critical functions of miRNAs in inflammatory and immunological processes in diabetes. We further emphasized the potential role of these miRNAs in controlling inflammation associated with diabetes. This assessment will direct the shift from many studies to practical applications for tailored diabetes treatment and assist in identifying new therapeutic targets and approaches.

Lipid metabolism-related genes are involved in the formation of macrophage extracellular traps in allergic airway inflammation

Recent studies have highlighted the critical role of lipid metabolism in macrophages concerning lung inflammation. However, it remains unclear whether lipid metabolism is involved in macrophage extracellular traps (METs). We analyzed the GSE40885 dataset from the GEO database using weighted correlation network analysis (WGCNA) and further selection using the least absolute shrinkage and selection operator (LASSO) regression. We identified ABCA1, SLC44A2, and C3 as key genes jointly involved in lipid metabolism and METs. Additionally, immune infiltration analysis was performed using the Xcell and CIBERSORT algorithms, while single-cell transcriptome analysis was utilized using data from the Tabula Muris database. The expression of key genes was validated in external datasets (GSE42606, GSE27066, GSE137268, and GSE256534). Notably, our results indicated that ABCA1 expression was elevated in patients experiencing acute asthma exacerbations, which aligned with its expression trend in lipopolysaccharide (LPS)-induced macrophages. However, ABCA1 expression was reduced in cases of chronic and severe asthma. Results from immunofluorescence (IF), SYTOX Green staining, and Western blot analyses suggested that ABCA1 may play a role in the formation of METs both in vivo and in vitro. In conclusion, this study indicates that ABCA1 may be involved in METs. ABCA1 may represent a promising therapeutic target for asthma.

The Interplay Between Cytokines and MicroRNAs to Regulate Metabolic Disorders

Metabolic disorders represent significant public health challenges worldwide. Emerging evidence suggests that cytokines and microRNAs (miRNAs) play crucial roles in the pathogenesis of metabolic disorders by regulating various metabolic processes, including insulin sensitivity, lipid metabolism, and inflammation. This review provides a comprehensive overview of the intricate interplay between cytokines and miRNAs in the context of metabolic disorders, including obesity, type 2 diabetes, and cardiovascular diseases. We discuss how dysregulation of cytokine-miRNA networks contributes to the development and progression of metabolic disorders and explore the therapeutic potential of targeting these interactions for disease management.

Anti-atherosclerosis mechanisms associated with regulation of non-coding RNAs by active monomers of traditional Chinese medicine

Atherosclerosis is the leading cause of numerous cardiovascular diseases with a high mortality rate. Non-coding RNAs (ncRNAs), RNA molecules that do not encode proteins in human genome transcripts, are known to play crucial roles in various physiological and pathological processes. Recently, researches on the regulation of atherosclerosis by ncRNAs, mainly including microRNAs, long non-coding RNAs, and circular RNAs, have gradually become a hot topic. Traditional Chinese medicine has been proved to be effective in treating cardiovascular diseases in China for a long time, and its active monomers have been found to target a variety of atherosclerosis-related ncRNAs. These active monomers of traditional Chinese medicine hold great potential as drugs for the treatment of atherosclerosis. Here, we summarized current advancement of the molecular pathways by which ncRNAs regulate atherosclerosis and mainly highlighted the mechanisms of traditional Chinese medicine monomers in regulating atherosclerosis through targeting ncRNAs.

Modulation of the Cellular microRNA Landscape: Contribution to the Protective Effects of High-Density Lipoproteins (HDL)

High-density lipoproteins (HDL) play an established role in protecting against cellular dysfunction in a variety of different disease contexts; however, harnessing this therapeutic potential has proved challenging due to the heterogeneous and relative instability of this lipoprotein and its variable cargo molecules. The purpose of this study is to examine the contribution of microRNA (miRNA; miR) sequences, either delivered directly or modulated endogenously, to these protective functions. This narrative review introduces the complex cargo carried by HDL, the protective functions associated with this lipoprotein, and the factors governing biogenesis, export and the uptake of microRNA. The possible mechanisms by which HDL can modulate the cellular miRNA landscape are considered, and the impact of key sequences modified by HDL is explored in diseases such as inflammation and immunity, wound healing, angiogenesis, dyslipidaemia, atherosclerosis and coronary heart disease, potentially offering new routes for therapeutic intervention.

Targeted Expression to Liver of an antimiR-33 Sponge as a Gene Therapy Strategy against Hypercholesterolemia: In Vitro Study

Atherosclerosis is the leading cause of cardiovascular diseases in Mexico and worldwide. The membrane transporters ABCA1 and ABCG1 are involved in the reverse transport of cholesterol and stimulate the HDL synthesis in hepatocytes, therefore the deficiency of these transporters promotes the acceleration of atherosclerosis. MicroRNA-33 (miR-33) plays an important role in lipid metabolism and exerts a negative regulation on the transporters ABCA1 and ABCG1. It is known that by inhibiting the function of miR-33 with antisense RNA, HDL levels increase and atherogenic risk decreases. Therefore, in this work, a genetic construct, pPEPCK-antimiR-33-IRES2-EGFP, containing a specific antimiR-33 sponge with two binding sites for miR-33 governed under the PEPCK promoter was designed, constructed, and characterized, the identity of which was confirmed by enzymatic restriction, PCR, and sequencing. Hep G2 and Hek 293 FT cell lines, as well as a mouse hepatocyte primary cell culture were transfected with this plasmid construction showing expression specificity of the PEPCK promoter in hepatic cells. An analysis of the relative expression of miR-33 target messengers showed that the antimiR-33 sponge indirectly induces the expression of its target messengers (ABCA1 and ABCG1). This strategy could open new specific therapeutic options for hypercholesterolemia and atherosclerosis, by blocking the miR-33 specifically in hepatocytes.

Effects of miR-33 Deficiency on Metabolic and Cardiovascular Diseases: Implications for Therapeutic Intervention

MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally inhibit gene expression. These small molecules are involved in several biological conditions such as inflammation, cell growth and proliferation, and regulation of energy metabolism. In the context of metabolic and cardiovascular diseases, miR-33 is of particular interest as it has been implicated in the regulation of lipid and glucose metabolism. This miRNA is located in introns harboured in the genes encoding sterol regulatory element-binding protein (SREBP)-1 and SREBP-2, which are key transcription factors involved in lipid biosynthesis and cholesterol efflux. This review outlines the role of miR-33 in a range of metabolic and cardiovascular pathologies, such as dyslipidaemia, nonalcoholic fatty liver disease (NAFLD), obesity, diabetes, atherosclerosis, and abdominal aortic aneurysm (AAA), and it provides discussion about the effectiveness of miR-33 deficiency as a possible therapeutic strategy to prevent the development of these diseases.

Dietary cholesterol consumption and incidence of type 2 diabetes mellitus: A dose-response meta-analysis of prospective cohort studies

BACKGROUND AND AIM

The purpose of this meta-analysis was to evaluate the dose-response relationship between dietary cholesterol (DC) consumption and the incidence of type 2 diabetes mellitus (T2DM).

METHODS AND RESULTS

Prospective studies with the endpoint of T2DM were included. The Random-effect model weighted by inverse variance was used. Meta-regression and subgroup analyses were conducted to explore the potential sources of heterogeneity by specified study characteristics. Restricted cubic splines regression models were used to estimate the dose-response relationship. 11 prospective studies comprising of 355 230 subjects were included. Compared to lowest DC consumption, highest DC consumption was associated with an increased risk of T2DM (RR 1.15, 95% CI 1.03 to 1.28, P = 0.012; chi-squared = 31.41, I-squared 58.6%, P _{heterogeneity} = 0.003). Subgroup analyses have shown that this positive association was more evident in western countries than in eastern countries (RR 1.19, 95% CI 1.06 to 1.36 VS 1.34, 95% CI 0.84 to 1.29; P _{subgroup difference} = 0.02). For 100 mg/d increment in DC intake, the pooled RR was 1.05, (95% CI 1.04 to 1.07, P_linearity = 0.000, P_nonlinearity = 0.02), 1.06 (95% CI 1.04 to 1.07, P_linearity=0.000), and 1.01 (95% CI 0.98 to 1.05, P_linearity = 0.525) for the incidence of T2DM, in western and eastern countries, respectively.

CONCLUSIONS

Our study suggests that there is a positive dose-response association between DC consumption and the incidence of T2DM, especially in western countries.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020216318.

Regulation of cholesterol homeostasis in health and diseases: from mechanisms to targeted therapeutics

Disturbed cholesterol homeostasis plays critical roles in the development of multiple diseases, such as cardiovascular diseases (CVD), neurodegenerative diseases and cancers, particularly the CVD in which the accumulation of lipids (mainly the cholesteryl esters) within macrophage/foam cells underneath the endothelial layer drives the formation of atherosclerotic lesions eventually. More and more studies have shown that lowering cholesterol level, especially low-density lipoprotein cholesterol level, protects cardiovascular system and prevents cardiovascular events effectively. Maintaining cholesterol homeostasis is determined by cholesterol biosynthesis, uptake, efflux, transport, storage, utilization, and/or excretion. All the processes should be precisely controlled by the multiple regulatory pathways. Based on the regulation of cholesterol homeostasis, many interventions have been developed to lower cholesterol by inhibiting cholesterol biosynthesis and uptake or enhancing cholesterol utilization and excretion. Herein, we summarize the historical review and research events, the current understandings of the molecular pathways playing key roles in regulating cholesterol homeostasis, and the cholesterol-lowering interventions in clinics or in preclinical studies as well as new cholesterol-lowering targets and their clinical advances. More importantly, we review and discuss the benefits of those interventions for the treatment of multiple diseases including atherosclerotic cardiovascular diseases, obesity, diabetes, nonalcoholic fatty liver disease, cancer, neurodegenerative diseases, osteoporosis and virus infection.

Monocyte miRNAs Are Associated With Type 2 Diabetes

miRNAs are small noncoding RNAs that may contribute to common diseases through epigenetic regulation of gene expression. Little is known regarding the role of miRNAs in type 2 diabetes (T2D). We performed miRNA sequencing and transcriptomic profiling of peripheral monocytes from the longitudinal Multi-Ethnic Study of Atherosclerosis (MESA) (N = 1,154). We examined associations between miRNAs and prevalent impaired fasting glucose and T2D and evaluated the T2D-associated miRNA effect on incident T2D. Of 774 detected miRNAs, 6 (miR-22-3p, miR-33a-5p, miR-181c-5p, miR-92b-3p, miR-222-3p, and miR-944) were associated with prevalent T2D. For five of the six miRNAs (all but miR-222-3p), our findings suggest a dose-response relationship with impaired fasting glucose and T2D. Two of the six miRNAs were associated with incident T2D (miR-92b-3p: hazard ratio [HR] 1.64, P = 1.30E-03; miR-222-3p: HR 1.97, P = 9.10E-03) in the highest versus lowest tertile of expression. Most of the T2D-associated miRNAs were also associated with HDL cholesterol concentrations. The genes targeted by these miRNAs belong to key nodes of a cholesterol metabolism transcriptomic network. Higher levels of miRNA expression expected to increase intracellular cholesterol accumulation in monocytes are linked to an increase in T2D risk.

Efficacy and Safety of PCSK9 Monoclonal Antibodies in Patients With Diabetes

PURPOSE

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are novel drugs that have proven efficacy in improving cardiovascular outcomes. Roles for the PCSK9 molecule in metabolic pathways beyond LDL receptor processing and cholesterol homeostasis are well established. PCSK9 genetic variants associated with lower LDL-C levels correlate with a higher incidence of type 2 diabetes (T2DM), calling into question the appropriateness of these drugs in patients with T2DM and those at high risk of developing diabetes, and whether cardiovascular benefit seen with PCSK9 inhibitors might be offset by resultant dysglycemia. The purpose of this review was to examine the role of PCSK9 protein in glucose homeostasis, the impact of PCSK9 inhibition in relation to glucose homeostasis, and whether some of the cardiovascular benefit seen with PCSK9 inhibitors and statins might be offset by resultant dysglycemia.

METHODS

Comprehensive literature searches of electronic databases of PubMed, EMBASE, and OVID were conducted by using the search terms hyperlipidaemia, PCSK9, diabetes, and glucose as well as other relevant papers of interest collected by the authors. The retrieved papers were reviewed and shortlisted most relevant ones.

FINDINGS

Genetically determined lower circulating LDL-C and PCSK9 concentrations may have an incremental effect in increasing T2DM incidence, but any perceived harm is outweighed by the reduced risk of atherosclerotic cardiovascular disease achieved through lower lifetime exposure to LDL-C. PCSK9 monoclonal antibodies are effective and safe in patients with T2DM and those at high risk of developing it. The number-needed-to-treat to prevent one atherosclerotic cardiovascular disease event in the FOURIER (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) study in the subgroup with diabetes is significantly lower than for those without. Therefore, T2DM or being at high risk to develop it should not be a reason to avoid these agents. The safety of PCSK9 inhibition in relation to glucose homeostasis may depend on the method of inhibition and whether it occurs in circulation or the cells. Data from experimental studies and randomized controlled trials suggest no detrimental effect of PCSK9 monoclonal antibodies on glucose homeostasis. More data and large randomized controlled studies are needed to assess the impact of other methods of PCSK9 inhibition on glucose homeostasis.

IMPLICATIONS

PCSK9monoclonal antibodies markedly reduce LDL-C and consistently reduce cardiovascular mortality in patients with and without diabetes. Current evidence does not suggest an adverse effect of PCSK9 monoclonal antibodies on glycemic parameters.

Comprehensive miRNA and DNA Microarray Analyses Reveal the Response of Hepatic miR-203 and Its Target Gene to Protein Malnutrition in Rats

Adequate protein nutrition is essential for good health. Effects of protein malnutrition in animals have been widely studied at the mRNA level with the development of DNA microarray technology. Although microRNAs (miRNAs) have attracted attention for their function in regulating gene expression and have been studied in several disciplines, fewer studies have clarified the effects of protein malnutrition on miRNA alterations. The present study aimed to elucidate the relationship between protein malnutrition and miRNAs. Six-week old Wistar male rats were fed a control diet (20% casein) or a low-protein diet (5% casein) for two weeks, and their livers were subjected to both DNA microarray and miRNA array analysis. miR-203 was downregulated and its putative target Hadhb (hydroxyacyl-CoA dehydrogenase β subunit), known to regulate β-oxidation of fatty acids, was upregulated by the low-protein diet. In an in vitro experiment, miR-203 or its inhibitor were transfected in HepG2 cells, and the pattern of Hadhb expression was opposite to that of miR-203 expression. In addition, to clarifying the hepatic miRNA profile in response to protein malnutrition, these results showed that a low-protein diet increased Hadhb expression through downregulation of miR-203 and induced β-oxidation of fatty acids.

Statins Are Associated With Increased Insulin Resistance and Secretion

Objective

Statin treatment reduces the risk of atherosclerotic cardiovascular disease but is associated with a modest increased risk of type 2 diabetes, especially in those with insulin resistance or prediabetes. Our objective was to determine the physiological mechanism for the increased type 2 diabetes risk.

Approach and Results

We conducted an open-label clinical trial of atorvastatin 40 mg daily in adults without known atherosclerotic cardiovascular disease or type 2 diabetes at baseline. The co-primary outcomes were changes at 10 weeks versus baseline in insulin resistance as assessed by steady-state plasma glucose during the insulin suppression test and insulin secretion as assessed by insulin secretion rate area under the curve (ISRAUC) during the graded-glucose infusion test. Secondary outcomes included glucose and insulin, both fasting and during oral glucose tolerance test. Of 75 participants who enrolled, 71 completed the study (median age 61 years, 37% women, 65% non-Hispanic White, median body mass index, 27.8 kg/m2). Atorvastatin reduced LDL (low-density lipoprotein)-cholesterol (median decrease 53%, P<0.001) but did not change body weight. Compared with baseline, atorvastatin increased insulin resistance (steady-state plasma glucose) by a median of 8% (P=0.01) and insulin secretion (ISRAUC) by a median of 9% (P<0.001). There were small increases in oral glucose tolerance test glucoseAUC (median increase, 0.05%; P=0.03) and fasting insulin (median increase, 7%; P=0.01).

Conclusions

In individuals without type 2 diabetes, high-intensity atorvastatin for 10 weeks increases insulin resistance and insulin secretion. Over time, the risk of new-onset diabetes with statin use may increase in individuals who become more insulin resistant but are unable to maintain compensatory increases in insulin secretion.

HDL and type 2 diabetes: the chicken or the egg?

HDL is a complex macromolecular cluster of various components, such as apolipoproteins, enzymes and lipids. Quality evidence from clinical and epidemiological studies led to the principle that HDL-cholesterol (HDL-C) levels are inversely correlated with the risk of CHD. Nevertheless, the failure of many cholesteryl ester transfer protein inhibitors to protect against CVD casts doubts on this principle and highlights the fact that HDL functionality, as dictated by its proteome and lipidome, also plays an important role in protecting against metabolic disorders. Recent data indicate that HDL-C levels and HDL particle functionality are correlated with the pathogenesis and prognosis of type 2 diabetes mellitus, a major risk factor for CVD. Hyperglycaemia leads to reduced HDL-C levels and deteriorated HDL functionality, via various alterations in HDL particles' proteome and lipidome. In turn, reduced HDL-C levels and impaired HDL functionality impact the performance of key organs related to glucose homeostasis, such as pancreas and skeletal muscles. Interestingly, different structural alterations in HDL correlate with distinct metabolic abnormalities, as indicated by recent data evaluating the role of apolipoprotein A1 and lecithin-cholesterol acyltransferase deficiency in glucose homeostasis. While it is becoming evident that not all HDL disturbances are causatively associated with the development and progression of type 2 diabetes, a bidirectional correlation between these two conditions exists, leading to a perpetual self-feeding cycle.

Higher egg consumption associated with increased risk of diabetes in Chinese adults - China Health and Nutrition Survey

The association between egg consumption and diabetes is inconclusive. We aimed to examine the association between long-term egg consumption and its trajectory with diabetes in Chinese adults. A total of 8545 adults aged ≥18 years old who attended the China Health and Nutrition Survey from 1991 to 2009 were included in this analysis. Egg consumption at each survey was assessed by a 3-d 24-h recall and weighed food record methods. The consumption trajectories of eggs were modelled with the latent class group approach. Diabetes was diagnosed based on fasting blood glucose in 2009. Logistic regression was used to examine the association. The mean age of the study population was 50·9 (sd 15·1) years. About 11·1 % had diabetes in 2009. Egg consumption nearly doubled in 2009 from 16 g/d in 1991. Compared with the first quartile of egg consumption (0-9·0 g/d), the adjusted OR of diabetes for the second (9·1-20·6 g/d), third (20·7-37·5 g/d) and fourth (≥37·6 g/d) quartiles were 1·29 (95 % CI 1·03, 1·62), 1·37 (95 % CI 1·09, 1·72) and 1·25 (95 % CI 1·04, 1·64), respectively (Pfor trend = 0·029). Three trajectory groups of egg consumption were identified. Compared with group 1 (30·7 %, low baseline intake and slight increase), both group 2 (62·2 %, medium baseline intake and increase) and group 3 (7·1 %, high baseline intake and decrease) were associated with an increased OR for diabetes. The results suggested that higher egg consumption was positively associated with the risk of diabetes in Chinese adults.

Association between preoperative lipid profiles and new-onset diabetes after transplantation in Chinese kidney transplant recipients: A retrospective cohort study

Background

This study investigated the association between the preoperative lipid profiles and new‐onset diabetes after transplantation (NODAT) in Chinese kidney transplant recipients (KTRs).

Methods

In this study, of 1140 KTRs registered between January 1993 and March 2018 in Zhongshan Hospital, Fudan University, 449 were enrolled. Clinical data, obtained through a chart review of the patient records in the medical record system, were evaluated, and NODAT was diagnosed based on the American Diabetes Association guidelines. Multivariate Cox regression analysis was conducted to determine whether the preoperative lipid profiles in KTRs were independently associated with NODAT incidence. The preoperative lipid profiles were analyzed as continuous variables and grouped into tertiles. Smooth curve fitting was used to confirm the linear associations.

Results

During a median follow‐up of 28.03 (interquartile range 12.00–84.23) months, 104 of the 449 (23.16%) participants developed NODAT. The multivariate model analysis, adjusted for all potential covariates, showed that increased values of the following parameters were associated with NODAT (hazard ratio, 95% confidence interval): preoperative total cholesterol (TC; 1.25, 1.09–1.58, p = 0.0495), low‐density lipoprotein cholesterol (LDL‐C; 1.33, 1.02–1.75, p = 0.0352), non‐high‐density lipoprotein cholesterol (non‐HDL‐C; 1.41, 1.09–1.82, p = 0.0084), TC/HDL‐C (1.28, 1.06–1.54, p = 0.0109), and non‐HDL‐C/HDL‐C (1.26, 1.05–1.52, p = 0.0138). However, the association between the preoperative triglyceride, HDL‐C, or TG/HDL‐C and NODAT was not significant.

Conclusions

Preoperative TC, LDL‐C, non‐HDL‐C, TC/HDL‐C, and non‐HDL‐C/HDL‐C were independent risk factors for NODAT.

miR-33 in cardiometabolic diseases: lessons learned from novel animal models and approaches

miRNAs have emerged as critical regulators of nearly all biologic processes and important therapeutic targets for numerous diseases. However, despite the tremendous progress that has been made in this field, many misconceptions remain among much of the broader scientific community about the manner in which miRNAs function. In this review, we focus on miR‐33, one of the most extensively studied miRNAs, as an example, to highlight many of the advances that have been made in the miRNA field and the hurdles that must be cleared to promote the development of miRNA‐based therapies. We discuss how the generation of novel animal models and newly developed experimental techniques helped to elucidate the specialized roles of miR‐33 within different tissues and begin to define the specific mechanisms by which miR‐33 contributes to cardiometabolic diseases including obesity and atherosclerosis. This review will summarize what is known about miR‐33 and highlight common obstacles in the miRNA field and then describe recent advances and approaches that have allowed researchers to provide a more complete picture of the specific functions of this miRNA.

Implication of epigenetic factors in the pathogenesis of type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease that resulted from the severe destruction of the insulin-producing β cells in the pancreases of individuals with a genetic predisposition. Genome-wide studies have identified HLA and other risk genes associated with T1D susceptibility in humans. However, evidence obtained from the incomplete concordance of diabetes incidence among monozygotic twins suggests that environmental factors also play critical roles in T1D pathogenesis. Epigenetics is a rapidly growing field that serves as a bridge to link T1D risk genes and environmental exposures, thereby modulating the expression of critical genes relevant to T1D development beyond the changes of DNA sequences. Indeed, there is compelling evidence that epigenetic changes induced by environmental insults are implicated in T1D pathogenesis. Herein, we sought to summarize the recent progress in terms of epigenetic mechanisms in T1D initiation and progression, and discuss their potential as biomarkers and therapeutic targets in the T1D setting.

Protection against Glucolipotoxicity by High Density Lipoprotein in Human PANC-1 Hybrid 1.1B4 Pancreatic Beta Cells: The Role of microRNA

High-density lipoproteins provide protection against the damaging effects of glucolipotoxicity in beta cells, a factor which sustains insulin secretion and staves off onset of type 2 diabetes mellitus. This study examines epigenetic changes in small non-coding microRNA sequences induced by high density lipoproteins in a human hybrid beta cell model, and tests the impact of delivery of a single sequence in protecting against glucolipotoxicity. Human PANC-1.1B4 cells were used to establish Bmax and Kd for [³H]cholesterol efflux to high density lipoprotein, and minimum concentrations required to protect cell viability and reduce apoptosis to 30mM glucose and 0.25 mM palmitic acid. Microchip array identified the microRNA signature associated with high density lipoprotein treatment, and one sequence, hsa-miR-21-5p, modulated via delivery of a mimic and inhibitor. The results confirm that low concentrations of high-density lipoprotein can protect against glucolipotoxicity, and report the global microRNA profile associated with this lipoprotein; delivery of miR-21-5p mimic altered gene targets, similar to high density lipoprotein, but could not provide sufficient protection against glucolipotoxicity. We conclude that the complex profile of microRNA changes due to HDL treatment may be difficult to replicate using a single microRNA, findings which may inform current drug strategies focused on this approach.

The Predominant microRNAs in β-cell Clusters for Insulin Regulation and Diabetic Control

micro (mi)-RNAs are vital regulators of multiple processes including insulin signaling pathways and glucose metabolism. Pancreatic β-cells function is dependent on some miRNAs and their target mRNA, which together form a complex regulative network. Several miRNAs are known to be directly involved in β-cells functions such as insulin expression and secretion. These small RNAs may also play significant roles in the fate of β-cells such as proliferation, differentiation, survival and apoptosis. Among the miRNAs, miR-7, miR-9, miR-375, miR-130 and miR-124 are of particular interest due to being highly expressed in these cells. Under diabetic conditions, although no specific miRNA profile has been noticed, the expression of some miRNAs and their target mRNAs are altered by posttranscriptional mechanisms, exerting diverse signs in the pathobiology of various diabetic complications. The aim of this review article is to discuss miRNAs involved in the process of stem cells differentiation into β-cells, resulting in enhanced β-cell functions with respect to diabetic disorders. This paper will also look into the impact of miRNA expression patterns on in vitro proliferation and differentiation of β-cells. The efficacy of the computational genomics and biochemical analysis to link the changes in miRNA expression profiles of stem cell-derived β-cells to therapeutically relevant outputs will be discussed as well.

Srebf2 Locus Overexpression Reduces Body Weight, Total Cholesterol and Glucose Levels in Mice Fed with Two Different Diets

Macronutrients represent risk factors for hyperlipidemia or diabetes. Lipid alterations and type 2 diabetes mellitus are global health problems. Overexpression of sterol regulatory element-binding factor (Srebf2) in transgenic animals is linked to elevated cholesterol levels and diabetes development. We investigated the impact of increased Srebf2 locus expression and the effects of control and high-fat, high-sucrose (HFHS) diets on body weight, glucose and lipid metabolisms in transgenic mice (S-mice). Wild type (WT) and S-mice were fed with both diets for 16 weeks. Plasma glucose, insulin and lipids were assessed (n = 25). Immunostainings were performed in liver, pancreas and fat (N = 10). Expression of Ldlr and Hmgcr in liver was performed by RT-PCR (N = 8). Control diet: S-mice showed reduced weight, insulin, total and HDL cholesterol and triglycerides (TG). HFHS diet widened differences in weight, total and HDL cholesterol, insulin and HOMA index but increased TG in S-mice. In S-mice, adipocyte size was lower while HFHS diet produced lower increase, pancreatic β-cell mass was lower with both diets and Srebf2, Ldlr and Hmgcr mRNA levels were higher while HFHS diet produced a rise in Srebf2 and Hmgcr levels. Srebf2 complete gene overexpression seems to have beneficial effects on metabolic parameters and to protect against HFHS diet effects.

Therapeutic Potentials of MicroRNAs for Curing Diabetes Through Pancreatic β-Cell Regeneration or Replacement

MicroRNAs are a type of noncoding RNAs that regulates the expression of target genes at posttranscriptional level. MicroRNAs play essential roles in regulating the expression of different genes involved in pancreatic development, β-cell mass maintenance, and β-cell function. Alteration in the level of miRNAs involved in β-cell function leads to the diabetes. Being an epidemic, diabetes threatens the life of millions of patients posing a pressing demand for its urgent resolve. However, the currently available therapies are not substantial to cure the diabetic epidemic. Thus, researchers are trying to find new ways to replenish the β-cell mass in patients with diabetes. One promising approach is the in vivo regeneration of β-cell mass or increasing the efficiency of β-cell function. Another clinical strategy is the transplantation of in vitro developed β-like cells. Owing to their role in pancreatic β-cell development, maintenance, functioning and their involvement in diabetes, overexpression or attenuation of different miRNAs can cause β-cell regeneration in vivo or can direct the differentiation of various kinds of stem/progenitor cells to β-like cells in vitro. Here, we will summarize different strategies used by researchers to investigate the therapeutic potentials of miRNAs, with focus on miR-375, for curing diabetes through β-cell regeneration or replacement.

Regulation of ATP binding cassette transporter A1 (ABCA1) expression: cholesterol-dependent and - independent signaling pathways with relevance to inflammatory lung disease

The role of the ATP binding cassette transporter A1 (ABCA1) in maintaining cellular lipid homeostasis in cardiovascular disease is well established. More recently, the important beneficial role played by ABCA1 in modulating pathogenic disease mechanisms, such as inflammation, in a broad range of chronic conditions has been realised. These studies position ABCA1 as a potential therapeutic target in a diverse range of diseases where inflammation is an underlying cause. Chronic respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD) are driven by inflammation, and as such, there is now a growing recognition that we need a greater understanding of the signaling pathways responsible for regulation of ABCA1 expression in this clinical context. While the signaling pathways responsible for cholesterol-mediated ABCA1 expression have been clearly delineated through decades of studies in the atherosclerosis field, and thus far appear to be translatable to the respiratory field, less is known about the cholesterol-independent signaling pathways that can modulate ABCA1 expression in inflammatory lung disease. This review will identify the various signaling pathways and ligands that are associated with the regulation of ABCA1 expression and may be exploited in future as therapeutic targets in the setting of chronic inflammatory lung diseases.

Wnt antagonist DKK-1 levels in systemic sclerosis are lower in skin but not in blood and are regulated by microRNA33a-3p

BACKGROUND

Systemic sclerosis is an autoimmune skin disease which is associated with inflammation and resulting skin fibrosis. Myofibroblasts are the key cell type associated with the fibrosis but how they are differentiated is not clear. DKK-1 is a Wnt antagonist that blocks Wnt-mediated fibrosis and is reduced in fibrotic conditions. Thus, DKK-1 is a clear negative regulator of fibrosis in systemic sclerosis and its regulation is unknown. The aim of this work is to determine the levels of DKK-1 in serum and tissues of SSc and its regulation.

METHODS

Skin biopsies were taken from early diffuse systemic sclerosis patients and healthy controls and DKK-1 measured by ELISA; serum was also isolated and DKK-1 quantified. DKK-1 was also measured by qRT-PCR. MicroRNA33a-3p was measured by TaqMan PCR. miR mimics and controls were transfected into dermal fibroblasts. Bleomycin mouse model was employed and compared to vehicle control treated mice, and gene expression was employed for DKK-1 and various extracellular matrix genes.

RESULTS

DKK-1 is reduced in SSc skin and fibroblasts but is not reduced in the circulation in patients. MicroRNA33a-3p regulates DKK-1 levels epigenetically and is significantly reduced in SSc cells and whole tissue. DKK-1 is also reduced in the bleomycin mouse model and pro-fibrotic genes elevated.

CONCLUSION

DKK-1 is reduced in SSc cells and is regulated by miR33a-3p, and restoring DKK-1 levels through epigenetic means could be a therapeutic target in systemic sclerosis.

MiR-190b impedes pancreatic β cell proliferation and insulin secretion by targeting NKX6-1 and may associate to gestational diabetes mellitus

BACKGROUND

The dysfunction of pancreatic β cells is related to the occurrence of gestational diabetes mellitus (GDM). This study aimed to investigate the mechanism underlying the effects of miR-190b on pancreatic β cell proliferation and insulin secretion.

METHODS

Quantitative real-time PCR was used to detect miR-190b expression in placenta tissues from GDM patients. The effects of miR-190b on islet cells activity, proliferation, and insulin secretion were measured using MTT assay, BrdU staining, and ELISA. The relationship between miR-190b and NK6 homeobox 1 (NKX6-1) was ensured by dual luciferase reporter assay.

RESULTS

MiR-190b was overexpressed in placenta tissues from GDM patients compared to normal pregnant woman. MiR-190b inhibitor inhibited the cell activity, proliferation, and insulin secretion of islet β cells, while miR-190b overexpression had an opposite effect. Additionally, miR-190b negatively regulated NKX6-1 expression. Overexpression of NKX6-1 reversed the inhibitory effect of miR-190b-mimics on islet β cell activity, proliferation, and insulin secretion. In mouse islets, knockdown of miR-190b promoted insulin secretion by up-regulating NKX6-1 expression.

CONCLUSION

Silence of miR-190b accelerated pancreatic β cell proliferation and insulin secretion via targeting NKX6-1, which might be a mechanism underlying the effects of miR-190b on the progression of GDM.

Affecting Lipid Metabolism Salivary MicroRNAs Expressions in Arabian Racehorses Before and After the Race

The active roles of microribonucleic acids (miRNAs) in gene regulation have made miRNAs a key point for the scientific world in the study of physiological processes. Although saliva includes the largest number of miRNAs, there is no miRNA study in saliva on horses has been found. Our study is the first study on miRNAs isolation from saliva in horses. In the present study, saliva was studied in Arabian racehorses to better understand the molecular mechanisms of expression levels that are effective in lipid metabolism of miRNAs and their target genes during the race. Identification of lipid metabolism of miRNAs and their target genes is an opportunity to provide information about biomarkers in Arabian racehorses on energy supply for race performance. Arabian racehorses have low glycogen content and high triglyceride storage capability, thanks to the high amount of oxidative type I fiber in their muscle tissue. Therefore, Arabian racehorses can provide higher levels of energy using more fat. The aim of this study is to determine the prerace and postrace expression levels of eight miRNAs in saliva that are known to affect lipid metabolism in Arabian racehorses. The expression level of eca-miR-33a was found to be statistically significant (P < .05). Target genes of eca-miR-33a have been copredicted as ABCA1, CROT, ABHD2, and SATB2, with three validated databases and other analysis tools. In conclusion, these findings revealed that both eca-miR-33a and its target genes could be potential core genes that play important roles in lipid metabolism in Arabian racehorses to provide energy during the race.

Role of microRNA-33a in malignant cells

Cancer causes most of the mortality and morbidity worldwide, with a significant increase in incidence during recent years. MicroRNAs (miRNAs/miRs) are non-coding small RNAs capable of regulating gene expression. They regulate crucial cellular processes, including proliferation, differentiation, metastasis and apoptosis. Therefore, abnormal miRNA expression is associated with multiple diseases, including cancer. There are two types of cancer-associated miRNAs, oncogenic and tumor suppressor miRNAs, depending on their roles and expression patterns in cancer. Accordingly, miRNAs are considered to be targets for cancer prevention and treatment. miR-33a controls cellular cholesterol uptake and synthesis, which are both closely associated with carcinogenesis. The present review thoroughly describes the roles of miR-33a in more than a dozen types of cancer and the underlying mechanisms. Accordingly, the present review may serve as a guide for researchers studying the involvement of miR-33a in diverse cancer settings.

Statin Treatment-Induced Development of Type 2 Diabetes: From Clinical Evidence to Mechanistic Insights

Statins are the gold-standard treatment for the prevention of primary and secondary cardiovascular disease, which is the leading cause of mortality worldwide. Despite the safety and relative tolerability of statins, observational studies, clinical trials and meta-analyses indicate an increased risk of developing new-onset type 2 diabetes mellitus (T2DM) after long-term statin treatment. It has been shown that statins can impair insulin sensitivity and secretion by pancreatic β-cells and increase insulin resistance in peripheral tissues. The mechanisms involved in these processes include, among others, impaired Ca²⁺ signaling in pancreatic β-cells, down-regulation of GLUT-4 in adipocytes and compromised insulin signaling. In addition, it has also been described that statins’ impact on epigenetics may also contribute to statin-induced T2DM via differential expression of microRNAs. This review focuses on the evidence and mechanisms by which statin therapy is associated with the development of T2DM. This review describes the multifactorial combination of effects that most likely contributes to the diabetogenic effects of statins. Clinically, these findings should encourage clinicians to consider diabetes monitoring in patients receiving statin therapy in order to ensure early diagnosis and appropriate management.

MicroRNA-33a-5p sponges to inhibit pancreatic β-cell function in gestational diabetes mellitus LncRNA DANCR

BACKGROUND

Gestational diabetes mellitus (GDM) is the most common medical complication associated with pregnancy, which may impose risks on both mother and fetus. Micro RNAs (miRNAs) and long noncoding RNAs (lncRNAs) are implied as vital regulators in GDM. A recent paper revealed dysregulation of miR-33a-5p in placental tissues of GDM patients. However, the biological function of miR-33a-5p in GDM remains elusive. This study focused on exploring the function and underlying mechanisms of miR-33a-5p in GDM.

METHODS

12 GDM pregnancies and 12 healthy pregnancies were enrolled in the study. INS-1 cell line was applied in in vitro experiments. The expression levels of miR-33a-5p, lnc-DANCR (Differentiation Antagonizing Non-Protein Coding RNA), and ABCA1 (ATP-binding cassette transporter 1) mRNA were determined by RT-qPCR assay. Glucose and insulin levels were measured by ELISA assay. Luciferase reporter assay and western blot assay were applied to validate the target of miR-33a-5p.

RESULTS

miR-33a-5p was upregulated in the blood samples from GDM, and was positively correlated with blood glucose (p < 0.0001). Overexpression or inhibition of miR-33a-5p significantly inhibited or promoted cell growth and insulin production of INS-1 cells (p < 0.01). Furthermore, ABCA1 is a direct target of miR-33a-5p, and lnc-DANCR functions as a sponge for miR-33a-5p to antagonize the function of miR-33a-5p in INS-1 cells.

CONCLUSION

Our study demonstrated that lnc-DANCR-miR-33a-5p-ABCA1 signaling cascade plays a crucial role in the regulation of the cellular function of INS-1 cells.

Lipid efflux mechanisms, relation to disease and potential therapeutic aspects

Lipids are hydrophobic and amphiphilic molecules involved in diverse functions such as membrane structure, energy metabolism, immunity, and signaling. However, altered intra-cellular lipid levels or composition can lead to metabolic and inflammatory dysfunction, as well as lipotoxicity. Thus, intra-cellular lipid homeostasis is tightly regulated by multiple mechanisms. Since most peripheral cells do not catabolize cholesterol, efflux (extra-cellular transport) of cholesterol is vital for lipid homeostasis. Defective efflux contributes to atherosclerotic plaque development, impaired β-cell insulin secretion, and neuropathology. Of these, defective lipid efflux in macrophages in the arterial walls leading to foam cell and atherosclerotic plaque formation has been the most well studied, likely because a leading global cause of death is cardiovascular disease. Circulating high density lipoprotein particles play critical roles as acceptors of effluxed cellular lipids, suggesting their importance in disease etiology. We review here mechanisms and pathways that modulate lipid efflux, the role of lipid efflux in disease etiology, and therapeutic options aimed at modulating this critical process.

Fine-tuning of microRNAs in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus is a metabolic disease widely spread across industrialized countries. Sedentary lifestyle and unhealthy alimentary habits lead to obesity, boosting both glucose and fatty acid in the bloodstream and eventually, insulin resistance, pancreas inflammation and faulty insulin production or secretion, all of them very well-defined hallmarks of type 2 diabetes mellitus. miRNAs are small sequences of non-coding RNA that may regulate several processes within the cells, fine-tuning protein expression, with an unexpected and subtle precision and in time-frames ranging from minutes to days. Since the discovery of miRNA and their possible implication in pathologies, several groups aimed to find a relationship between type 2 diabetes mellitus and miRNAs. Here we discuss the pattern of expression of different miRNAs in cultured cells, animal models and diabetic patients. We summarize the role of the most important miRNAs involved in pancreas growth and development, insulin secretion and liver, skeletal muscle or adipocyte insulin resistance in the context of type 2 diabetes mellitus.

ATP-binding cassette A1 deficiency causes cardiolipin-driven mitochondrial dysfunction in podocytes

Fibroblasts from patients with Tangier disease carrying ATP-binding cassette A1 (ABCA1) loss-of-function mutations are characterized by cardiolipin accumulation, a mitochondrial-specific phospholipid. Suppression of ABCA1 expression occurs in glomeruli from patients with diabetic kidney disease (DKD) and in human podocytes exposed to DKD sera collected prior to the development of DKD. We demonstrated that siRNA ABCA1 knockdown in podocytes led to reduced oxygen consumption capabilities associated with alterations in the oxidative phosphorylation (OXPHOS) complexes and with cardiolipin accumulation. Podocyte-specific deletion of Abca1 (Abca1fl/fl) rendered mice susceptible to DKD, and pharmacological induction of ABCA1 improved established DKD. This was not mediated by free cholesterol, as genetic deletion of sterol-o-acyltransferase-1 (SOAT1) in Abca1fl/fl mice was sufficient to cause free cholesterol accumulation but did not cause glomerular injury. Instead, cardiolipin mediates ABCA1-dependent susceptibility to podocyte injury, as inhibition of cardiolipin peroxidation with elamipretide improved DKD in vivo and prevented ABCA1-dependent podocyte injury in vitro and in vivo. Collectively, we describe a pathway definitively linking ABCA1 deficiency to cardiolipin-driven mitochondrial dysfunction. We demonstrated that this pathway is relevant to DKD and that ABCA1 inducers or inhibitors of cardiolipin peroxidation may each represent therapeutic strategies for the treatment of established DKD.

The Profiling and Role of miRNAs in Diabetes Mellitus

Diabetes mellitus (DM), a complex metabolic disease, has become a global threat to human health worldwide. Over the past decades, an enormous amount of effort has been devoted to understand how microRNAs (miRNAs), a class of small non-coding RNA regulators of gene expression at the post-transcriptional level, are implicated in DM pathology. Growing evidence suggests that the expression signature of a specific set of miRNAs has been altered in the progression of DM. In the present review, we summarize the recent investigations on the miRNA profiles as novel DM biomarkers in clinical studies and in animal models, and highlight recent discoveries on the complex regulatory effect and functional role of miRNAs in DM.

Genetic obesity increases pancreatic expression of mitochondrial proteins which regulate cholesterol efflux in BRIN-BD11 insulinoma cells

Pancreatic β-cells are sensitive to fluctuations in cholesterol content, which can damage the insulin secretion pathway, contributing to the aetiology of type 2 diabetes mellitus. Cholesterol efflux to (apo)lipoproteins, via ATP-binding cassette (ABC) transporter A1 (ABCA1), can prevent intracellular cholesterol accumulation; in some peripheral cells, ABCA1-dependent efflux is enhanced by promotion of cholesterol trafficking to, and generation of Liver X receptor (LXR) ligands by, mitochondrial sterol 27-hydroxylase (Cyp27A1 (cytochrome P450 27 A1/sterol 27-hydroxylase)) and its redox partners, adrenodoxin (ADX) and ADX reductase (ADXR). Despite this, the roles of mitochondrial cholesterol trafficking (steroidogenic acute regulatory protein [StAR] and 18-kDa translocator protein [TSPO]) and metabolising proteins in insulin-secreting cells remain wholly uncharacterised. Here, we demonstrate an increase in pancreatic expression of Cyp27A1, ADXR, TSPO and LXRα, but not ADX or StAR, in obese (fa/fa) rodents compared with lean (Fa/?) controls. Overexpression of Cyp27A1 alone in BRIN-BD11 cells increased INS2 expression, without affecting lipid metabolism; however, after exposure to low-density lipoprotein (LDL), cholesterol efflux to (apo)lipoprotein acceptors was enhanced in Cyp27A1-overexpressing cells. Co-transfection of Cyp27A1, ADX and ADXR, at a ratio approximating that in pancreatic tissue, stimulated cholesterol efflux to apolipoprotein A-I (apoA-I) in both basal and cholesterol-loaded cells; insulin release was stimulated equally by all acceptors in cholesterol-loaded cells. Thus, genetic obesity increases pancreatic expression of Cyp27A1, ADXR, TSPO and LXRα, while modulation of Cyp27A1 and its redox partners promotes cholesterol efflux from insulin-secreting cells to acceptor (apo)lipoproteins; this response may help guard against loss of insulin secretion caused by accumulation of excess intracellular cholesterol.

microRNA-33-3p involved in selenium deficiency-induced apoptosis via targeting ADAM10 in the chicken kidney

Selenium (Se) deficiency induces typical clinical and pathological changes and causes various pathological responses at the molecular level in several different chicken organs; the kidney is one of the target organs of Se deficiency. To explore the mechanisms that underlie the effects of microRNA-33-3p (miR-33-3p) on Se deficiency-induced kidney apoptosis, 60 chickens were randomly divided into two groups (30 chickens per group). We found that Se deficiency increased the expression of miR-33-3p in the chicken kidney. A disintegrin and metalloprotease domain 10 (ADAM10) was verified to be a target of miR-33-3p in the chicken kidney. The overexpression of miR-33-3p decreased the expression levels of β-catenin, cyclinD1, T-cell factor (TCF), c-myc, survivin, and Bcl-2; it increased the expression levels of E-cadherin, Bak, Bax, and caspase-3; and it increased the number of chicken kidney cells in the G0/G1 phase. In addition, Se deficiency caused the ultrastructure of the kidney to develop apoptotic characteristics. The results of flow cytometry analysis and AO/EB staining showed that the number of apoptotic chicken kidney cells increased in the miR-33-3p mimic group. All these results suggest that Se deficiency-induced cell cycle arrest and apoptosis in vivo and in vitro in the chicken kidney via the regulation of miR-33-3p, which targets ADAM10.

Specialized Pro-resolving Lipid Mediators: Modulation of Diabetes-Associated Cardio-, Reno-, and Retino-Vascular Complications

Diabetes and its associated chronic complications present a healthcare challenge on a global scale. Despite improvements in the management of chronic complications of the micro-/macro-vasculature, their growing prevalence and incidence highlights the scale of the problem. It is currently estimated that diabetes affects 425 million people globally and it is anticipated that this figure will rise by 2025 to 700 million people. The vascular complications of diabetes including diabetes-associated atherosclerosis and kidney disease present a particular challenge. Diabetes is the leading cause of end stage renal disease, reflecting fibrosis leading to organ failure. Moreover, diabetes associated states of inflammation, neo-vascularization, apoptosis and hypercoagulability contribute to also exacerbate atherosclerosis, from the metabolic syndrome to advanced disease, plaque rupture and coronary thrombosis. Current therapeutic interventions focus on regulating blood glucose, glomerular and peripheral hypertension and can at best slow the progression of diabetes complications. Recently advanced knowledge of the pathogenesis underlying diabetes and associated complications revealed common mechanisms, including the inflammatory response, insulin resistance and hyperglycemia. The major role that inflammation plays in many chronic diseases has led to the development of new strategies aiming to promote the restoration of homeostasis through the "resolution of inflammation." These strategies aim to mimic the spontaneous activities of the 'specialized pro-resolving mediators' (SPMs), including endogenous molecules and their synthetic mimetics. This review aims to discuss the effect of SPMs [with particular attention to lipoxins (LXs) and resolvins (Rvs)] on inflammatory responses in a series of experimental models, as well as evidence from human studies, in the context of cardio- and reno-vascular diabetic complications, with a brief mention to diabetic retinopathy (DR). These data collectively support the hypothesis that endogenously generated SPMs or synthetic mimetics of their activities may represent lead molecules in a new discipline, namely the 'resolution pharmacology,' offering hope for new therapeutic strategies to prevent and treat, specifically, diabetes-associated atherosclerosis, nephropathy and retinopathy.

Circulating miRNA-33: a potential biomarker in patients with coronary artery disease

BACKGROUND

Circulating microRNAs (miRNA) are present in body fluids in stable, cell-free form. Likewise, these miRNAs can be identified in various stages of coronary artery disease (CAD) such as inflammation, endothelial dysfunction, proliferation and atherosclerosis among others. miRNA expression levels can be identified.

AIMS AND OBJECTIVES

To determine the expression of circulating miRNAs (miR-126, miR-92, miR-33, miR-145 and miR-155) in CAD patients of Indian origin.

MATERIAL AND METHODS

miRNA profiling analysis in blood plasma was performed by quantitative real-time-PCR (qRT-PCR) in 60 angiographically verified subjects including 30 CAD patients and 30 age- and gender-matched controls. Association between the expression of all five circulating miRNAs and clinical characteristics of patients with CAD were analysed using Medcalc statistics. The severity of CAD was assessed using SYNTAX score (SS).

RESULTS

Expression of plasma miR-33 increased by 2.9 folds in CAD patients than in control group (p value ≥0.002) also it was found that miR-33 expression levels in mild cases (SS: ≤22) were significantly higher than CAD controls. There was a modest negative correlation between miR-33 and total cholesterol/high density lipoprotein ratio, triglycerides and very low density lipoprotein.

CONCLUSION

The study reports a significant association between increased levels of plasma miR-33 and CAD. Thus, plasma miR-33 appears to be a promising non-invasive biomarker, but requires further validation in a large cohort.

Hepatocyte miR-33a mediates mitochondrial dysfunction and hepatosteatosis by suppressing NDUFA5

Emerging evidence suggests that microRNAs (miRNAs) are essential for metabolic haemostasis of liver tissues. Among them, miR‐33a is supposed to modulate the cholesterol export and fatty acid oxidation, but whether miR‐33a involves in the process of fatty liver disease is unclear. To disclose the hypothesis, we utilized miR‐33a mimic and antisense to explore their effects in primary hepatocytes or high‐fat diet (HFD)‐fed mice. Treatment with palmitic acid (PA) or HFD significantly increased the expression of miR‐33a in hepatocytes or liver tissues. In primary hepatocytes, miR‐33a mimic decreased mitochondrial function, including reduction of ATP production and oxygen consumption, whereas miR‐33a inhibition protected PA‐induced mitochondrial dysfunction. Interestingly, miR‐33a selectively suppressed mitochondrial complex I activity and protein expression, but not other complexes. Through bioinformatics prediction, we found miR‐33a directly targeted on the 3′‐UTR of NDUFA5. Dual‐luciferase reporter analysis further confirmed the direct suppression of miR‐33a on NDUFA5 expression. More importantly, administration of miR‐33a antisense could effectively restore HFD‐induced mitochondrial dysfunction through up‐regulation of NDUFA5 levels. Mice treated with miR‐33a antisense also exhibited improved liver function and structural disorders under obese status. Taken together, miR‐33a was an important mediator of hepatocyte mitochondrial function, and the therapeutic benefits implied miR‐33a antisense had the potential clinical application in combating the fatty liver disease.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Non-high-density lipoprotein cholesterol: High-density lipoprotein cholesterol ratio is an independent risk factor for diabetes mellitus: Results from a population-based cohort study

BACKGROUND

Dyslipidemia predicts the development and progression of diabetes. A higher non-high-density lipoprotein cholesterol (HDL-C):  HDL-C ratio is reportedly associated with metabolic syndrome and insulin resistance, but its relationship with glycemic levels and diabetes remains unclear.

METHODS

In all, 4882 subjects aged ≥40 years without diabetes and not using lipid-lowering drugs were enrolled in the study. The non-HDL-C:  HDL-C ratio was log₁₀ transformed to achieve normal distribution. Multivariate logistic regression was used to investigate the association between the log₁₀ -transformed non-HDL-C:  HDL-C ratio and diabetes. Stratified analyses of the association by age, gender, and body mass index (BMI) were also performed.

RESULTS

After 3 years of follow-up, 704 participants developed diabetes. After adjustment for age, gender, current smoking, current drinking, physical activity, BMI, systolic blood pressure, and family history of diabetes, each 1-SD increase in the log(non-HDL-C:  HDL-C ratio) was associated with higher fasting blood glucose (FPG) levels (β = 0.1; 95% confidence interval [CI] 0.1-0.1), 2-h postload plasma glucose levels (2-h glucose; β = 0.2; 95% CI 0.1-0.2), and risk of diabetes (odds ratio [OR] 1.1; 95% CI 1.0-1.2). In a multivariate model, subjects in the top quartile of non-HDL-C:  HDL-C ratio had higher FPG (β = 0.2; 95% CI 0.2-0.3), 2-h glucose (β = 0.5; 95% CI 0.3-0.7) and HbA1c (β = 0.1; 95% CI 0.1-0.2) levels, and a 40% increased risk of diabetes (OR 1.4; 95% CI 1.1-1.8) than participants in the bottom quartile.

CONCLUSIONS

The non-HDL-C:  HDL-C ratio was found to be an independent risk factor for diabetes.

Visceral adipose tissue-derived serine protease inhibitor accelerates cholesterol efflux by up-regulating ABCA1 expression via the NF-κB/miR-33a pathway in THP-1 macropahge-derived foam cells

Atherosclerosis is a dyslipidemia disease characterized by foam cell formation driven by the accumulation of lipids. Visceral adipose tissue-derived serine protease inhibitor (vaspin) is known to suppress the development of atherosclerosis via its anti-inflammatory properties, but it is not yet known whether vaspin affects cholesterol efflux in THP-1 macrophage-derived foam cells. Here, we investigated the effects of vaspin on ABCA1 expression and cholesterol efflux, and further explored the underlying mechanism. We found that vaspin decreased miR-33a levels, which in turn increased ABCA1 expression and cholesteorl efflux. We also found that inhibition of NF-κB reduced miR-33a expression and vaspin suppressed LPS-mediated NF-κB phosphorylation. Our findings suggest that vaspin is not only a regular of inflammasion but also a promoter of cholesterol efflux.

Changes of Circulating MicroRNAs in Response to Treatment With Teriparatide or Denosumab in Postmenopausal Osteoporosis

CONTEXT

Expression of microRNAs (miRs) related to bone metabolism in the serum may be affected by antiosteoporotic treatment.

OBJECTIVE

To investigate the effect of two antiosteoporotic agents with opposite effects on bone metabolism on miR expression profile in the serum.

DESIGN

Observational, open label, nonrandomized clinical trial.

SETTING

The outpatient clinics for Metabolic Bone Diseases of 424 General Military Hospital, Thessaloniki, Greece.

PATIENTS AND INTERVENTIONS

Postmenopausal women with low bone mass were treated with either teriparatide (TPTD; n = 30) or denosumab (n = 30) for 12 months.

MAIN OUTCOME MEASURES

Changes in the serum expression of selected miRs linked to bone metabolism at 3 and 12 months of treatment. Secondary measurements: associations of measured miRs with changes in bone mineral density (BMD) at 12 months and the bone turnover markers (BTMs) C-terminal cross-linking telopeptide of type I collagen and procollagen type I N-terminal propeptide at 3 and 12 months.

RESULTS

We found significantly decreased relative expression of miR-33-3p at 3 months (P = 0.03) and of miR-133a at 12 months (P = 0.042) of TPTD treatment. BMD values at 12 months of TPTD treatment were significantly and inversely correlated with miR-124-3p expression at 3 months (P = 0.008). Relative expression of miR-24-3p and miR-27a was correlated with changes in BTMs during TPTD treatment and of miR-21-5p, miR-23a-3p, miR-26a-5p, miR-27a, miR-222-5p, and miR-335-5p with changes in BTMs during denosumab treatment.

CONCLUSIONS

Circulating miRs are differentially affected by treatment with TPTD and denosumab. TPTD affects the relative expression of miRs related to the expression of RUNX-2 (miR-33) and DKK-1 gene (miR-133).

Suppression of Lipogenesis via Reactive Oxygen Species-AMPK Signaling for Treating Malignant and Proliferative Diseases

AIMS

Systemic diseases often have common characteristics. The aim of this study was to investigate the feasibility of targeting common pathological metabolism to inhibit the progression of malignant and proliferative diseases.

RESULTS

Gefitinib-resistant (G-R) nonsmall-cell lung cancer (NSCLC) and rheumatoid arthritis (RA) were studied as conditions representative of malignant and proliferative diseases, respectively. Strong lipogenic activity and high expression of sterol regulatory element-binding protein 1 (SREBP1) were found in both G-R NSCLC cells and synovial fibroblasts from RA patients (RASFs). Berberine (BBR), an effective suppressor of SREBP1 and lipogenesis regulated through reactive oxygen species (ROS)/AMPK pathway, selectively inhibited the growth of G-R NSCLC cells and RASFs but not that of normal cells. It effectively caused mitochondrial dysfunction, activated ROS/AMPK pathway, and finally suppressed cellular lipogenesis and cell proliferation. Addition of ROS blocker, AMPK inhibitor, and palmitic acid significantly reduced the effect of BBR. In an in vivo study, treatment of BBR led to significant inhibition of mouse tumor xenograft growth and remarkably slowed down the development of adjuvant-induced arthritis in rats. Innovation and Conclusion: Targeting ROS/AMPK/lipogenesis signaling pathway selectively inhibited the growth of G-R NSCLC cells and the progress of RASFs in vitro and in vivo, which provides a new avenue for treating malignancies and proliferative diseases. Antioxid. Redox Signal. 28, 339-357.

Connexins and microRNAs: Interlinked players in regulating islet function?

Pancreatic β-cells are connected to neighboring endocrine cells through the adherin proteins and gap junctions. Connexin 36 (Cx36) is one of the most well-studied and abundantly expressed gap-junction proteins within rodent islets, which is important in coordinated insulin secretion. The expression of connexins is regulated at various levels and by several mechanisms; one of which is via microRNAs. In past 2 decades, microRNAs (miRNAs) have emerged as key molecules in developmental, physiologic and pathological processes. However, very few studies have demonstrated miRNA-mediated regulation of connexins. Even though there are no reports yet on miRNAs and Cx36; we envisage that considering the important role of connexins and microRNAs in insulin secretion, there would be common pathways interlinking these biomolecules. Here, we discuss the current literature on connexins and miRNAs specifically with reference to islet function.