Orphan GPR26 Counteracts Early Phases of Hyperglycemia-Mediated Monocyte Activation and Is Suppressed in Diabetic Patients

Diabetes is the ninth leading cause of death, with an estimated 1.5 million deaths worldwide. Type 2 diabetes (T2D) results from the body's ineffective use of insulin and is largely the result of excess body weight and physical inactivity. T2D increases the risk of cardiovascular diseases, retinopathy, and kidney failure by two-to three-fold. Hyperglycemia, as a hallmark of diabetes, acts as a potent stimulator of inflammatory condition by activating endothelial cells and by dysregulating monocyte activation. G-protein couple receptors (GPCRs) can both exacerbate and promote inflammatory resolution. Genome-wide association studies (GWAS) indicate that GPCRs are differentially regulated in inflammatory and vessel cells from diabetic patients. However, most of these GPCRs are orphan receptors, for which the mechanism of action in diabetes is unknown. Our data indicated that orphan GPCR26 is downregulated in the PBMC isolated from T2D patients. In contrast, GPR26 was initially upregulated in human monocytes and PBMC treated with high glucose (HG) levels and then decreased upon chronic and prolonged HG exposure. GPR26 levels were decreased in T2D patients treated with insulin compared to non-insulin treated patients. Moreover, GPR26 inversely correlated with the BMI and the HbA1c of diabetic compared to non-diabetic patients. Knockdown of GPR26 enhanced monocyte ROS production, MAPK signaling, pro-inflammatory activation, monocyte adhesion to ECs, and enhanced the activity of Caspase 3, a pro-apoptotic molecule. The same mechanisms were activated by HG and exacerbated when GPR26 was knocked down. Hence, our data indicated that GPR26 is initially activated to protect monocytes from HG and is inhibited under chronic hyperglycemic conditions

Transcriptome analysis of human primary endothelial cells (HUVEC) from umbilical cords of gestational diabetic mothers reveals candidate sites for an epigenetic modulation of specific gene expression.

Within the complex pathological picture associated to diabetes, high glucose (HG) has ". per se" effects on cells and tissues that involve epigenetic reprogramming of gene expression. In fetal tissues, epigenetic changes occur genome-wide and are believed to induce specific long term effects. Human umbilical vein endothelial cells (HUVEC) obtained at delivery from gestational diabetic women were used to study the transcriptomic effects of chronic hyperglycemia in fetal vascular cells using Affymetrix microarrays. In spite of the small number of samples analyzed (n=6), genes related to insulin sensing and extracellular matrix reorganization were found significantly affected by HG. Quantitative PCR analysis of gene promoters identified a significant differential DNA methylation in TGFB2. Use of Ea.hy926 endothelial cells confirms data on HUVEC. Our study corroborates recent evidences suggesting that epigenetic reprogramming of gene expression occurs with persistent HG and provides a background for future investigations addressing genomic consequences of chronic HG. © 2014 Elsevier Inc

Stuttering as a matter of delay in neural activation: A combined TMS/EEG study

Objective: Brain dynamics in developmental stuttering (DS) are not well understood. The supplementary motor area (SMA) plays a crucial role, since it communicates with regions related to planning/execution of movements, and with sub-cortical regions involved in paced/voluntary acts (such as speech). We used TMS combined with EEG to shed light on connections in DS, stimulating the SMA. Methods: TMS/EEG was recorded in adult DS and fluent speakers (FS), stimulating the SMA during rest. TMS-evoked potentials and source distribution were evaluated. Results: Compared to FS, stutterers showed lower activity of neural sources in early time windows: 66\u2013 82 ms in SMA, and 91\u2013102 ms in the left inferior frontal cortex and left inferior parietal lobule. Stutterers, however, showed higher activations in later time windows (i.e. from 260\u2013460 ms), in temporal/premotor regions of the right hemisphere. Conclusions: These findings represent the functional counterpart to known white matter and cortico- basal-thalamo-cortical abnormalities in DS. They also explain how white matter abnormalities and cortico-basal-thalamo-cortical dysfunctions may be associated in DS. Finally, a mechanism is proposed in which compensatory activity of the non-dominant (right) hemisphere is recruited. Significance: DS may be a disorder of neural timing that appears to be delayed compared to FS; new mechanisms that support stuttering symptoms are inferred; the SMA may be a promising target for neuro-rehabilitation

Endothelial Dicer promotes atherosclerosis and vascular inflammation by miRNA-103-mediated suppression of KLF4

MicroRNAs regulate the maladaptation of endothelial cells (ECs) to naturally occurring disturbed blood flow at arterial bifurcations resulting in arterial inflammation and atherosclerosis in response to hyperlipidemic stress. Here, we show that reduced endothelial expression of the RNAse Dicer, which generates almost all mature miRNAs, decreases monocyte adhesion, endothelial C-X-C motif chemokine 1 (CXCL1) expression, atherosclerosis and the lesional macrophage content in apolipoprotein E knockout mice (Apoe(-/-)) after exposure to a high-fat diet. Endothelial Dicer deficiency reduces the expression of unstable miRNAs, such as miR-103, and promotes Kruppel-like factor 4 (KLF4)-dependent gene expression in murine atherosclerotic arteries. MiR-103 mediated suppression of KLF4 increases monocyte adhesion to ECs by enhancing nuclear factor-kappa B-dependent CXCL1 expression. Inhibiting the interaction between miR-103 and KLF4 reduces atherosclerosis, lesional macrophage accumulation and endothelial CXCL1 expression. Overall, our study suggests that Dicer promotes endothelial maladaptation and atherosclerosis in part by miR103-mediated suppression of KLF4

Supplementary data from: Role of endothelial micronuclei-contained DNA in atherosclerosis

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miR-103 promotes endothelial maladaptation by targeting lncWDR59

Blood flow at arterial bifurcations and curvatures is naturally disturbed. Endothelial cells (ECs) fail to adapt to disturbed flow, which transcriptionally direct ECs toward a maladapted phenotype, characterized by chronic regeneration of injured ECs. MicroRNAs (miRNAs) can regulate EC maladaptation through targeting of protein-coding RNAs. However, long non-coding RNAs (lncRNAs), known epigenetic regulators of biological processes, can also be miRNA targets, but their contribution on EC maladaptation is unclear. Here we show that hyperlipidemia-and oxLDL-induced upregulation of miR-103 inhibits EC proliferation and promotes endothelial DNA damage through targeting of novel lncWDR59. MiR-103 impedes lncWDR59 interaction with Notch1-inhibitor Numb, therefore affecting Notch1-induced EC proliferation. Moreover, miR-103 increases the susceptibility of proliferating ECs to oxLDL-induced mitotic aberrations, characterized by an increased micronucleic formation and DNA damage accumulation, by affecting Notch1-related beta-catenin co-activation. Collectively, these data indicate that miR-103 programs ECs toward a maladapted phenotype through targeting of lncWDR59, which may promote atherosclerosis

A Non-Canonical Link between Non-Coding RNAs and Cardiovascular Diseases

Cardiovascular diseases (CVDs) are among the top leading causes of mortality worldwide. Besides canonical environmental and genetic changes reported so far for CVDs, non-coding RNAs (ncRNAs) have emerged as key regulators of genetic and epigenetic mechanisms involved in CVD progression. High-throughput and sequencing data revealed that almost 80% of the total genome not only encodes for canonical ncRNAs, such as micro and long ncRNAs (miRNAs and lncRNAs), but also generates novel non-canonical sub-classes of ncRNAs, such as isomiRs and miRNA- and lncRNA-like RNAs. Moreover, recent studies reveal that canonical ncRNA sequences can influence the onset and evolution of CVD through novel “non-canonical” mechanisms. However, a debate exists over the real existence of these non-canonical ncRNAs and their concrete biochemical functions, with most of the dark genome being considered as “junk RNA”. In this review, we report on the ncRNAs with a scientifically validated canonical and non-canonical biogenesis. Moreover, we report on canonical ncRNAs that play a role in CVD through non-canonical mechanisms of action

MicroRNAs and Long Non-Coding RNAs as Potential Candidates to Target Specific Motifs of SARS-CoV-2

The respiratory system is one of the most affected targets of SARS-CoV-2. Various therapies have been utilized to counter viral-induced inflammatory complications, with diverse success rates. Pending the distribution of an effective vaccine to the whole population and the achievement of “herd immunity”, the discovery of novel specific therapies is to be considered a very important objective. Here, we report a computational study demonstrating the existence of target motifs in the SARS-CoV-2 genome suitable for specific binding with endogenous human micro and long non-coding RNAs (miRNAs and lncRNAs, respectively), which can, therefore, be considered a conceptual background for the development of miRNA-based drugs against COVID-19. The SARS-CoV-2 genome contains three motifs in the 5′UTR leader sequence recognized by selective nucleotides within the seed sequence of specific human miRNAs. The seed of 57 microRNAs contained a “GGG” motif that promoted leader sequence-recognition, primarily through offset-6mer sites able to promote microRNAs noncanonical binding to viral RNA. Similarly, lncRNA H19 binds to the 5′UTR of the viral genome and, more specifically, to the transcript of the viral gene Spike, which has a pivotal role in viral infection. Notably, some of the non-coding RNAs identified in our study as candidates for inhibiting SARS-CoV-2 gene expression have already been proposed against diverse viral infections, pulmonary arterial hypertension, and related diseases

A Non-Canonical Link between Non-Coding RNAs and Cardiovascular Diseases

Cardiovascular diseases (CVDs) are among the top leading causes of mortality worldwide. Besides canonical environmental and genetic changes reported so far for CVDs, non-coding RNAs (ncRNAs) have emerged as key regulators of genetic and epigenetic mechanisms involved in CVD progression. High-throughput and sequencing data revealed that almost 80% of the total genome not only encodes for canonical ncRNAs, such as micro and long ncRNAs (miRNAs and lncRNAs), but also generates novel non-canonical sub-classes of ncRNAs, such as isomiRs and miRNA- and lncRNA-like RNAs. Moreover, recent studies reveal that canonical ncRNA sequences can influence the onset and evolution of CVD through novel “non-canonical” mechanisms. However, a debate exists over the real existence of these non-canonical ncRNAs and their concrete biochemical functions, with most of the dark genome being considered as “junk RNA”. In this review, we report on the ncRNAs with a scientifically validated canonical and non-canonical biogenesis. Moreover, we report on canonical ncRNAs that play a role in CVD through non-canonical mechanisms of action