Co-expression network analysis revealing the key lncRNAs in diabetic foot ulcers

Epigenetic modification: A novel insight into diabetic wound healing

Wound healing is an intricate and fine regulatory process. In diabetic patients, advanced glycation end products (AGEs), excessive reactive oxygen species (ROS), biofilm formation, persistent inflammation, and angiogenesis regression contribute to delayed wound healing. Epigenetics, the fast-moving science in the 21st century, has been up to date and associated with diabetic wound repair. In this review, we go over the functions of epigenetics in diabetic wound repair in retrospect, covering transcriptional and posttranscriptional regulation. Among these, we found that histone modification is widely involved in inflammation and angiogenesis by affecting macrophages and endothelial cells. DNA methylation is involved in factors regulation in wound repair but also affects the differentiation phenotype of cells in hyperglycemia. In addition, noncodingRNA regulation and RNA modification in diabetic wound repair were also generalized. The future prospects for epigenetic applications are discussed in the end. In conclusion, the study suggests that epigenetics is an integral regulatory mechanism in diabetic wound healing.

LncRNA DLEU1 promotes angiogenesis in diabetic foot ulcer wound healing by regulating miR-96-5p

BACKGROUND

Diabetic foot ulcer (DFU) carries high rates of major amputation and mortality.

AIMS

The goals of this study were to identify expression of circulating lncRNA DLEU1 and miR-96-5p in patients with diabetic foot ulcer (DFU) and to explore the function of lncRNA DLEU1/miR-96-5p axis in DFU.

METHODS

Matched patients with DFU and healthy individuals were randomly selected. Serum samples from all subjects were used for circulating lncRNA DLEU1 and miR-96-5p assessment by RT-qPCR. Receiver operating characteristic (ROC) curve was plotted to assess the discriminative capacity of lncRNA DLEU1 and miR-96-5p in identifying DFU. Cell proliferation was detected by CCK-8 assay. Cell apoptosis was assayed by Annexin V-FITC/PI staining method. Bioinformatics, luciferase reporter activity assay, and in vitro cell experiments were used to explore the relationship between lncRNA DLEU1 and miR-96-5p.

RESULTS

LncRNA DLEU1 and miR-96-5p were significantly up- and downregulated in patients with DFU, respectively, compared with controls. After ROC assessment, lncRNA DLEU1 and miR-96-5p were found to discriminate DFU from miR-96-5p. Furthermore, lncRNA DLEU1 inhibited human umbilical vein endothelial cells (HUVECs) cell proliferation and increased HUVECs apoptosis and oxidative stress through sponging miR-96-5p.

CONCLUSION

Our findings suggest lncRNA DLEU1 and miR-96-5p as circulating biomarkers for DFU. Also, we provide the clue for the pathogenic significance of lncRNA DLEU1/miR-96-5p in DFU, as well as insights for new potential targets.

lncRNA ANRIL accelerates wound healing in diabetic foot ulcers via modulating HIF1A/VEGFA signaling through interacting with FUS

BACKGROUND

Diabetic foot ulcer (DFU) is a frequently diagnosed complication of diabetes, and remains a heathcare burden worldwide. However, the pathogenesis of DFU is still largely unclear. The objective of this study is to delineate the function and underlying mechanism of lncRNA antisense non coding RNA in the INK4 locus (ANRIL) in endothelial progenitor cells (EPCs) and DFU mice.

METHODS

The DFU mouse model was established, and EPCs were subjected to high glucose (HG) treatment to mimic diabetes. qRT-PCR or western blot was employed to detected the expression of ANRIL, HIF1A, FUS and VEGFA. CCK-8 and Annexin V/PI staining were used to monitor cell proliferation and apoptosis. Wound healing, Transwell invasion and tube formation assays were conducted to assess cell migration, invasion and angiogenesis, respectively. The association between ANRIL and FUS was verified by RNA pull-down and RIP assays. Luciferase and ChIP assays were employed to investigate HIF1A-mediated transcriptional regulation of VEGFA and ANRIL. The histological alterations of DFU wound healing were observed by H&E and Masson staining.

RESULTS

ANRIL was downregulated in peripheral blood samples of DFU patients, DFU mice and HG-treated EPCs. Mechanistically, ANRIL regulated HIFA mRNA stability via recruiting FUS. VEGFA and ANRIL were transcriptionally regulated by HIF1A. Functional experiments revealed that HG suppressed EPC proliferation, migration, invasion and tube formation, but promoted apoptosis via ANRIL/HIF1A axis. ANRIL accelerated DFU wound healing via modulating HIF1A expression in vivo.

CONCLUSION

ANRIL accelerated wound healing in DFU via modulating HIF1A/VEGFA signaling in a FUS-dependent manner.

Circulating exosomal lncRNAs in patients with chronic coronary syndromes

INTRODUCTION

The concept of chronic coronary syndrome (CCS) was first presented at the European Society of Cardiology Meeting in 2019. However, the roles of exosomal lncRNAs in CCS remain largely unclear.

MATERIAL AND METHODS

A case-control study was performed with a total of 218 participants (137 males and 81 females), including 15 CCS patients and 15 controls for sequencing profiles, 20 CCS patients and 20 controls for the first validation, and 100 CCS patients and 48 controls for the second validation. Exosomes were isolated from the plasma of CCS patients and controls, and exosomal lncRNAs were identified by sequencing profiles and verified twice by qRT-PCR analysis. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of exosomal lncRNAs for CCS patients.

RESULTS

A total of 152 significantly differentially expressed lncRNAs with over two-fold changes were detected in plasma exosomes of CCS patients, including 90 upregulated and 62 downregulated lncRNAs. Importantly, 6 upregulated lncRNAs with the top fold changes were selected for validations. Exosomal lncRNAs ENST00000424615.2 and ENST00000560769.1 were significantly elevated in CCS patients in both validations compared with controls. The areas under the ROC of lncRNAs ENST00000424615.2 and ENST00000560769.1 were 0.654 and 0.722, respectively. Additionally, exosomal lncRNA ENST00000560769.1 was significantly higher in the CCS patients with more diseased vessels (p = 0.028).

CONCLUSIONS

Exosomal lncRNA ENST00000424615.2 and ENST00000560769.1 were identified as novel diagnosis biomarkers for patients with CCS. Moreover, exosomal lncRNA ENST00000560769.1 was significantly higher in the CCS patients with more diseased vessels, and might be associated with a poor prognosis.

Gene-Based Network Analysis Reveals Prognostic Biomarkers Implicated in Diabetic Tubulointerstitial Injury

Background

Diabetic nephropathy (DN), a significant cause of chronic kidney disease (CKD), is a devastating disease worldwide.

Objective

The aim of this study was to reveal crucial genes closely linked to the molecular mechanism of tubulointerstitial injury in DN.

Methods

The Gene Expression Omnibus (GEO) database was used to download the datasets. Based on this, a weighted gene coexpression network analysis (WGCNA) network was constructed to detect DN-related modules and hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichments were performed on the selected hub genes and modules. Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was performed on the obtained gene signature.

Results

The WGCNA network was constructed based on 3019 genes, and nine gene coexpression modules were generated. A total of 57 genes, including 34 genes in the magenta module and 23 genes in the purple module, were adapted as hub genes. 61 significantly downregulated and 119 upregulated genes were screened as differentially expressed genes (DEGs). 25 overlapping genes between hub genes chosen from WGCNA and DEG were identified. Through LASSO analysis, a 9-gene signature may be a potential prognostic biomarker for DN. To further explore the potential mechanism of DN, the different immune cell infiltrations between tubulointerstitial samples of DN and healthy samples were estimated.

Conclusions

This bioinformatics study identified CX3CR1, HRG, LTF, TUBA1A, GADD45B, PDK4, CLIC5, NDNF, and SOCS2 as candidate biomarkers for the diagnosis of DN. Moreover, DN tends to own a higher proportion of memory B cell.

Overexpression of miR-146a promotes cell proliferation and migration in a model of diabetic foot ulcers by regulating the AKAP12 axis

In the current study, we aimed to study the effect of miR-146a on proliferation and migration in an in vitro diabetic foot ulcer (DFU) model by targeting A-kinase-anchoring protein 12 (AKAP12). An in vitro DFU model was initially established using HaCaT cells derived from human keratinocytes and induced by advanced glycation end products (AGEs). The effects of overexpression of miR-146a on proliferation and migration ability were analysed. The expression levels of miR-146a and AKAP12 were measured by quantitative real-time polymerase chain reaction (qRT-PCR), and AKAP12, hypoxia-inducible factor-1α (HIF-1α), Wnt3a and β-catenin protein levels were measured by western blotting. The cell proliferation ability was measured by MTT, and the migration ability was analysed by a cell scratch assay. The binding between miR-146a and AKAP12 was identified using a luciferase reporter assay. The results demonstrated that AGEs significantly suppressed cell proliferation and migration, while the expression of miR-146a decreased and the expression of AKAP12 increased. A luciferase reporter assay revealed that miR-146a could directly target AKAP12. Overexpression of miR-146a promoted cell proliferation and migration in an in vitro DFU model and also promoted the expression of HIF-1α, Wnt3a and β-catenin but suppressed the expression of AKAP12. Co-overexpression of miR-146a and AKAP12 reversed the effect of miR-146a on cell proliferation and migration. Our findings revealed that miR-146a directly targeted AKAP12 and promoted cell proliferation and migration in an in vitro DFU model. This study provides a new perspective for the study of miR-146a in the treatment of DFU.

Diabetic Wound-Healing Science

Diabetes mellitus is an increasingly prevalent chronic metabolic disease characterized by prolonged hyperglycemia that leads to long-term health consequences. It is estimated that impaired healing of diabetic wounds affects approximately 25% of all patients with diabetes mellitus, often resulting in lower limb amputation, with subsequent high economic and psychosocial costs. The hyperglycemic environment promotes the formation of biofilms and makes diabetic wounds difficult to treat. In this review, we present updates regarding recent advances in our understanding of the pathophysiology of diabetic wounds focusing on impaired angiogenesis, neuropathy, sub-optimal chronic inflammatory response, barrier disruption, and subsequent polymicrobial infection, followed by current and future treatment strategies designed to tackle the various pathologies associated with diabetic wounds. Given the alarming increase in the prevalence of diabetes, and subsequently diabetic wounds, it is imperative that future treatment strategies target multiple causes of impaired healing in diabetic wounds.

Modulation of the Wound Healing through Noncoding RNA Interplay and GSK-3β/NF-κB Signaling Interaction

Diabetic foot ulcers are seriously endangering the physical and mental health of patients. Due to the long duration of inflammation, the treatment of nonhealing wounds in diabetes is one of the most prominent healthcare problems in the world. The nuclear factor kappa B (NF-κB) signaling pathway, a classical pathway that triggers inflammatory response, is regulated by many regulators, such as glycogen synthase kinase 3 beta (GSK-3β). Noncoding RNAs, a large class of molecules that regulate gene expression at the posttranscriptional or posttranslational level, play an important role in various stages of wound healing, especially in the stage of inflammation. Herein, we summarized the roles of noncoding RNAs in the NF-κB/GSK-3β signaling, which might provide new ideas for the treatment of diabetic wound healing.

The progress, prospects, and challenges of the use of non-coding RNA for diabetic wounds

Chronic diabetic wounds affect the quality of life of patients, resulting in significant social and economic burdens on both individuals and the health care system. Although treatment methods for chronic diabetic wounds have been explored, there remains a lack of effective treatment strategies; therefore, alternative strategies must be explored. Recently, the abnormal expression of non-coding RNA in diabetic wounds has received widespread attention since it is an important factor in the development of diabetic wounds. This article reviews the regulatory role of three common non-coding RNAs (microRNA [miRNA], long non-coding RNA [lncRNA], and circular RNA [circRNA]) in diabetic wounds and discusses the diagnosis, treatment potential, and challenges of non-coding RNA in diabetic wounds. This article provides insights into new strategies for diabetic wound diagnosis and treatment at the genetic and molecular levels.

Emerging Roles of Long Non-Coding RNAs in Diabetic Foot Ulcers

Diabetes mellitus is one of the most widespread metabolic diseases in the world, and diabetic foot ulcer (DFU), as one of its chronic complications, not only causes a large amount of physiological and psychological pain to patients but also places a tremendous burden on the entire economy and society. Despite significant advances in knowledge on the mechanism and in the treatment of DFU, clinical practice is still not satisfactory, and our understanding of its cellular and molecular pathogenesis is far from complete. Fortunately, progress in studying the roles of long non-coding RNAs (lncRNAs), which play important regulatory roles in the expression of genes at multiple levels, suggests that we can apply them in the early diagnosis and potential targeted intervention of DFU. In this review, we briefly summarize the current knowledge regarding the functional roles and potential mechanisms of reported lncRNAs in regulating DFU.

Role of Nrf2 in MALAT1/ HIF-1α loop on the regulation of angiogenesis in diabetic foot ulcer

Diabetic non healing wounds often result in significant morbidity and mortality. The number of effective targets to detect these wounds are meagre. Slow lymphangiogenesis is one of the complex processes involved in impaired healing of wounds. Long non coding RNAs (lncRNAs) have been importantly recognized for their role in pathological conditions. Multiple studies highlighting the role of lncRNAs in the regulation of several biological processes and complex diseases. Herein, we investigated the role of lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the progression of diabetic foot ulcer (DFU). We report a significant reduction in the expression of lncRNA MALAT1 in the infected DFU subjects which was positively correlated with the expression of angiogenic factors such as Nrf2, HIF-1α and VEGF. Further, expression of pro-inflammatory markers TNF-α and IL-6 were found to be increased while, the expression of anti-inflammatory marker IL-10 was decreased in infected DFU tissues. Involvement of lncRNA MALAT1 in angiogenesis in EA.hy926 cells was demonstrated by silencing the expression of Nrf2, HIF-1α, and VEGF through interference mediated by MALAT1. In addition, its inflammatory role was demonstrated by decreased expression of TNF-α, IL-6 and not affecting the expression of IL-10. Further, CRISPR-Cas9 knock out of Nrf2 decreased the expression of lncRNA MALAT1, HIF-1α and VEGF which revealed the association of Nrf2 in regulating MALAT1/HIF-1α loop through positive feedback mechanism. Collectively, our results suggested the role of Nrf2 on MALAT1/HIF-1α loop in the regulation of angiogenesis, which could act as a novel target in the treatment of diabetic wounds.