Monocyte miRNAs Are Associated With Type 2 Diabetes

Transcriptomic Profile of Lin-Sca1+c-kit (LSK) cells in db/db mice with long-standing diabetes

BACKGROUND

The Lin-Sca1+c-Kit+ (LSK) fraction of the bone marrow (BM) comprises multipotent hematopoietic stem cells (HSCs), which are vital to tissue homeostasis and vascular repair. While diabetes affects HSC homeostasis overall, the molecular signature of mRNA and miRNA transcriptomic under the conditions of long-standing type 2 diabetes (T2D;>6 months) remains unexplored.

METHODS

In this study, we assessed the transcriptomic signature of HSCs in db/db mice, a well-known and widely used model for T2D. LSK cells of db/db mice enriched using a cell sorter were subjected to paired-end mRNA and single-end miRNA seq library and sequenced on Illumina NovaSeq 6000. The mRNA sequence reads were mapped using STAR (Spliced Transcripts Alignment to a Reference), and the miRNA sequence reads were mapped to the designated reference genome using the Qiagen GeneGlobe RNA-seq Analysis Portal with default parameters for miRNA.

RESULTS

We uncovered 2076 out of 13,708 mRNAs and 35 out of 191 miRNAs that were expressed significantly in db/db animals; strikingly, previously unreported miRNAs (miR-3968 and miR-1971) were found to be downregulated in db/db mice. Furthermore, we observed a molecular shift in the transcriptome of HSCs of diabetes with an increase in pro-inflammatory cytokines (Il4, Tlr4, and Tnf11α) and a decrease in anti-inflammatory cytokine IL10. Pathway mapping demonstrated inflammation mediated by chemokine, cytokine, and angiogenesis as one of the top pathways with a significantly higher number of transcripts in db/db mice. These molecular changes were reflected in an overt defect in LSK mobility in the bone marrow. miRNA downstream target analysis unveils several mRNAs targeting leukocyte migration, microglia activation, phagosome formation, and macrophage activation signaling as their primary pathways, suggesting a shift to an inflammatory phenotype.

CONCLUSION

Our findings highlight that chronic diabetes adversely alters HSCs' homeostasis at the transcriptional level, thus potentially contributing to the inflammatory phenotype of HSCs under long-term diabetes. We also believe that identifying HSCs-based biomarkers in miRNAs or mRNAs could serve as diagnostic markers and potential therapeutic targets for diabetes and associated vascular complications.

MicroRNAs Associated with Metformin Treatment in the Diabetes Prevention Program

The Diabetes Prevention Program (DPP) randomized controlled trial demonstrated that metformin treatment reduced progression to type 2 diabetes (T2D) by 31% compared to placebo in adults with prediabetes. Circulating micro-ribonucleic acids (miRs) are promising biomarkers of T2D risk, but little is known about their associations with metformin regimens for T2D risk reduction. We compared the change in 24 circulating miRs from baseline to 2 years in a subset from DPP metformin intervention (n = 50) and placebo (n = 50) groups using Wilcoxon signed rank tests. Spearman correlations were used to evaluate associations between miR change and baseline clinical characteristics. Multiple linear regression was used to adjust for covariates. The sample was 73% female, 17% Black, 13% Hispanic, and 50 ± 11 years. Participants were obese, normotensive, prediabetic, and dyslipidemic. Change in 12 miR levels from baseline to 2 years was significantly different in the metformin group compared with placebo after adjusting for multiple comparisons: six (let-7c-5p, miR-151a-3p, miR-17-5p, miR-20b-5p, miR-29b-3p, and miR-93-5p) were significantly upregulated and six (miR-130b-3p, miR-22-3p, miR-222-3p, miR-320a-3p, miR-320c, miR-92a-3p) were significantly downregulated in the metformin group. These miRs help to explain how metformin is linked to T2D risk reduction, which may lead to novel biomarkers, therapeutics, and precision health strategies.

MicroRNAs Associated with Metformin Treatment in the Diabetes Prevention Program

The Diabetes Prevention Program (DPP) randomized controlled trial demonstrated that metformin treatment reduced progression to type 2 diabetes (T2D) by 31% compared to placebo in adults with prediabetes. Circulating micro-ribonucleic acids (miRs) are promising biomarkers of T2D risk, but little is known about their associations with metformin regimens for T2D risk reduction. We compared the change in 24 circulating miRs from baseline to 2 years in a subset from DPP metformin intervention (n = 50) and placebo (n = 50) groups using Wilcoxon signed rank tests. Spearman's correlations were used to evaluate associations between miR change and baseline clinical characteristics. Multiple linear regression was used to adjust for covariates. The sample was 73% female, 17% Black, 13% Hispanic, and 50 ± 11 years. Participants were obese, normotensive, prediabetic, and dyslipidemic. Change in 12 miR levels from baseline to 2 years was significantly different in the metformin group compared with placebo after adjusting for multiple comparisons: six (let-7c-5p, miR-151a-3p, miR-17-5p, miR-20b-5p, miR-29b-3p, and miR-93-5p) were significantly upregulated and six (miR-130b-3p, miR-22-3p, miR-222-3p, miR-320a-3p, miR-320c, miR-92a-3p) were significantly downregulated in the metformin group. These miRs help to explain how metformin is linked to T2D risk reduction, which may lead to novel biomarkers, therapeutics, and precision-health strategies.

Role of Increased miR-222-3p Expression in Peripheral Blood and Wound Marginal Tissues of Type 2 Diabetes Mellitus Patients with Diabetic Foot Ulcer

Purpose

To study the correlations of miR-222-3p expression in the peripheral blood and wound marginal tissues of type 2 diabetes mellitus (T2DM) patients with the onset of diabetic foot ulcer (DFU), as well as explore the clinical value possessed by miR-222-3p in the diagnosis and treatment outcomes of DFU.

Methods

The study included 70 T2DM patients who did not suffer foot ulcers (T2DM group), 146 T2DM patients who suffered foot ulcers (DFU group), as well as 70 normal controls (NC group). Quantitative real-time PCR determined the MiR-222-3p relative expression. Clinical features and risk factors regarding DFU were assessed. Multiple stepwise logistic regression analysis assisted in confirming whether miR-222-3p expression could serve for independently predicting the risk factors for DFU. ROC curve analysis evaluated the diagnostic value exhibited by miR-222-3p level against DFU.

Results

T2DM group exhibited an obviously higher MiR-222-3p expression relative to NC group [1.98 (0.98, 3.62) vs 0.92 (0.61, 1.87)] (P < 0.01), but DFU group exhibited an obviously higher miR-222-3p expression relative to T2DM group [5.61 (1.98, 10.24) vs 1.98 (0.98, 3.62)] (P < 0.01). Besides, miR-222-3p expression presented a negative correlation with DFU healing rate (P < 0.05). According to Kaplan-Meier survival curve analysis, the group with high miR-222-3p expression showed higher unhealed DFU cumulative rate relative to the group with low expression (log-rank, P = 0.011, 0.001, respectively). Multivariate logistic regression analysis confirmed that high miR-222-3p expressions could independently predict DFU risk (OR=3.85, 95% CI 1.18~12.37, P = 0.008). According to the ROC curve analysis, the AUC of miR-222-3p specific to DFU diagnosis reached 0.803, with the best sensitivity of 95.93% and best specificity of 96.27%.

Conclusion

The increased expression of miR-222-3p in the peripheral blood of T2DM patients is closely related to the occurrence of DFU. MiR-222-3p is a biomarker with potential clinical value in diagnosing and evaluating the prognosis of DFU.

Immunometabolism at the Heart of Cardiovascular Disease

Immune cell function among the myocardium, now more than ever, is appreciated to regulate cardiac function and pathophysiology. This is the case for both innate immunity, which includes neutrophils, monocytes, dendritic cells, and macrophages, as well as adaptive immunity, which includes T cells and B cells. This function is fueled by cell-intrinsic shifts in metabolism, such as glycolysis and oxidative phosphorylation, as well as metabolite availability, which originates from the surrounding extracellular milieu and varies during ischemia and metabolic syndrome. Immune cell crosstalk with cardiac parenchymal cells, such as cardiomyocytes and fibroblasts, is also regulated by complex cellular metabolic circuits. Although our understanding of immunometabolism has advanced rapidly over the past decade, in part through valuable insights made in cultured cells, there remains much to learn about contributions of in vivo immunometabolism and directly within the myocardium. Insight into such fundamental cell and molecular mechanisms holds potential to inform interventions that shift the balance of immunometabolism from maladaptive to cardioprotective and potentially even regenerative. Herein, we review our current working understanding of immunometabolism, specifically in the settings of sterile ischemic cardiac injury or cardiometabolic disease, both of which contribute to the onset of heart failure. We also discuss current gaps in knowledge in this context and therapeutic implications.

The Remnant Lipoprotein Hypothesis of Diabetes-Associated Cardiovascular Disease

Both type 1 and type 2 diabetes are associated with an increased risk of atherosclerotic cardiovascular disease (CVD). Research based on human-first or bedside-to-bench approaches has provided new insights into likely mechanisms behind this increased risk. Although both forms of diabetes are associated with hyperglycemia, it is becoming increasingly clear that altered lipoprotein metabolism also plays a critical role in predicting CVD risk in people with diabetes. This review examines recent findings indicating that increased levels of circulating remnant lipoproteins could be a missing link between diabetes and CVD. Although CVD risk associated with diabetes is clearly multifactorial in nature, these findings suggest that we should increase efforts in evaluating whether remnant lipoproteins or the proteins that govern their metabolism are biomarkers of incident CVD in people living with diabetes and whether reducing remnant lipoproteins will prevent the increased CVD risk associated with diabetes.

Bioinformatics Analysis of the Mechanisms of Diabetic Nephropathy via Novel Biomarkers and Competing Endogenous RNA Network

Diabetic nephropathy (DN) is one of the common chronic complications of diabetes with unclear molecular mechanisms, which is associated with end-stage renal disease (ESRD) and chronic kidney disease (CKD). Our study intended to construct a competing endogenous RNA (ceRNA) network via bioinformatics analysis to determine the potential molecular mechanisms of DN pathogenesis. The microarray datasets (GSE30122 and GSE30529) were downloaded from the Gene Expression Omnibus database to find differentially expressed genes (DEGs). GSE51674 and GSE155188 datasets were used to identified the differentially expressed microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), respectively. The DEGs between normal and DN renal tissues were performed using the Linear Models for Microarray (limma) package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to reveal the mechanisms of DEGs in the progression of DN. The protein-protein interactions (PPI) of DEGs were carried out by STRING database. The lncRNA-miRNA-messenger RNA (mRNA) ceRNA network was constructed and visualized via Cytoscape on the basis of the interaction generated through the miRDB and TargetScan databases. A total of 94 significantly upregulated and 14 downregulated mRNAs, 31 upregulated and 121 downregulated miRNAs, and nine upregulated and 81 downregulated lncRNAs were identified. GO and KEGG pathways enriched in several functions and expression pathways, such as inflammatory response, immune response, identical protein binding, nuclear factor kappa b (NF-κB) signaling pathway, and PI3K-Akt signaling pathway. Based on the analysis of the ceRNA network, five differentially expressed lncRNAs (DElncRNAs) (SNHG6, KCNMB2-AS1, LINC00520, DANCR, and PCAT6), five DEmiRNAs (miR-130b-5p, miR-326, miR-374a-3p, miR-577, and miR-944), and five DEmRNAs (PTPRC, CD53, IRF8, IL10RA, and LAPTM5) were demonstrated to be related to the pathogenesis of DN. The hub genes were validated by using receiver operating characteristic curve (ROC) and real-time PCR (RT-PCR). Our research identified hub genes related to the potential mechanism of DN and provided new lncRNA-miRNA-mRNA ceRNA network that contributed to diagnostic and potential therapeutic targets for DN.