Long noncoding RNA LEENE promotes angiogenesis and ischemic recovery in diabetes models

Role of long noncoding RNAs in diabetes-associated peripheral arterial disease

Diabetes mellitus (DM) is a metabolic disease that heightens the risks of many vascular complications, including peripheral arterial disease (PAD). Various types of cells, including but not limited to endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages (MΦs), play crucial roles in the pathogenesis of DM-PAD. Long non-coding RNAs (lncRNAs) are epigenetic regulators that play important roles in cellular function, and their dysregulation in DM can contribute to PAD. This review focuses on the developing field of lncRNAs and their emerging roles in linking DM and PAD. We review the studies investigating the role of lncRNAs in crucial cellular processes contributing to DM-PAD, including those in ECs, VSMCs, and MΦ. By examining the intricate molecular landscape governed by lncRNAs in these relevant cell types, we hope to shed light on the roles of lncRNAs in EC dysfunction, inflammatory responses, and vascular remodeling contributing to DM-PAD. Additionally, we provide an overview of the research approach and methodologies, from identifying disease-relevant lncRNAs to characterizing their molecular and cellular functions in the context of DM-PAD. We also discuss the potential of leveraging lncRNAs in the diagnosis and therapeutics for DM-PAD. Collectively, this review provides a summary of lncRNA-regulated cell functions contributing to DM-PAD and highlights the translational potential of leveraging lncRNA biology to tackle this increasingly prevalent and complex disease.

Multimodal smart systems reprogramme macrophages and remove urate to treat gouty arthritis

Gouty arthritis is a chronic and progressive disease characterized by high urate levels in the joints and by an inflammatory immune microenvironment. Clinical data indicate that urate reduction therapy or anti-inflammatory therapy alone often fails to deliver satisfactory outcomes. Here we have developed a smart biomimetic nanosystem featuring a 'shell' composed of a fusion membrane derived from M2 macrophages and exosomes, which encapsulates liposomes loaded with a combination of uricase, platinum-in-hyaluronan/polydopamine nanozyme and resveratrol. The nanosystem targets inflamed joints and promotes the accumulation of anti-inflammatory macrophages locally, while the uricase and the nanozyme reduce the levels of urate within the joints. Additionally, site-directed near-infrared irradiation provides localized mild thermotherapy through the action of platinum and polydopamine, initiating heat-induced tissue repair. Combined use of these components synergistically enhances overall outcomes, resulting in faster recovery of the damaged joint tissue.

Mapping Endothelial-Macrophage Interactions in Diabetic Vasculature: Role of TREM2 in Vascular Inflammation and Ischemic Response

Vasculopathies occur 15 years earlier in individuals with diabetes mellitus (DM) as compared to those without, but the underlying mechanisms driving diabetic vasculopathy remain incompletely understood. Endothelial cells (ECs) and macrophages (MΦ) are critical players in vascular wall and their crosstalk is crucial in diabetic vasculopathy. In diabetes, EC activation enables monocyte recruitment, which transmigrate into the intima and differentiate into macrophages (MΦ). Beyond this established model of diapedesis, EC-MΦ interplay is highly intricate and heterogenous. To capture these highly context dependent EC-MΦ interactions, we leveraged single-cell (sc)RNA-seq in conjunction with spatial transcriptome (ST)-seq profiling to analyze human mesenteric arteries from non-diabetic (ND) and type 2 diabetic (T2D) donors. We provide in this study a transcriptomic map encompassing major arterial vascular cells, e.g., EC, mononuclear phagocyte (MP), and T cells, and their interactions associated with human T2D. Furthermore, we identified Triggering Receptor Expressed on Myeloid Cells 2 ( TREM2) as a top T2D-induced gene in MP, with concomitant increase of TREM2 ligands in ECs. TREM2 induction was confirmed in mouse models of T2D and monocyte/MΦ subjected to DM-mimicking stimuli. Perturbing TREM2 with either an antibody or silencing RNA in MPs led to decreased pro-inflammatory responses in MPs and ECs and increased EC migration in vitro . In a mouse model of diabetes, TREM2 expression and its interaction with ECs are increased in the ischemic, as compared to non-ischemic muscles. Importantly, neutralization of TREM2 using a neutralizing antibody enhanced ischemic recovery and flow reperfusion in the diabetic mice, suggesting a role of TREM2 in promoting diabetic PAD. Finally, we verified that both TREM2 expression and the TREM2-EC-interaction are increased in human patients with DM-PAD. Collectively, our study presents the first atlas of human diabetic vessels with a focus on EC-MP interactions. Exemplified by TREM2, our study provides valuable insights into EC-MΦ interactions, key processes contributing to diabetic vasculopathies and the potential of targeting these interactions for therapeutic development.

Icariin accelerates bone regeneration by inducing osteogenesis-angiogenesis coupling in rats with type 1 diabetes mellitus

BACKGROUND

Icariin (ICA), a natural flavonoid compound monomer, has multiple pharmacological activities. However, its effect on bone defect in the context of type 1 diabetes mellitus (T1DM) has not yet been examined.

AIM

To explore the role and potential mechanism of ICA on bone defect in the context of T1DM.

METHODS

The effects of ICA on osteogenesis and angiogenesis were evaluated by alkaline phosphatase staining, alizarin red S staining, quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence. Angiogenesis-related assays were conducted to investigate the relationship between osteogenesis and angiogenesis. A bone defect model was established in T1DM rats. The model rats were then treated with ICA or placebo and micron-scale computed tomography, histomorphometry, histology, and sequential fluorescent labeling were used to evaluate the effect of ICA on bone formation in the defect area.

RESULTS

ICA promoted bone marrow mesenchymal stem cell (BMSC) proliferation and osteogenic differentiation. The ICA treated-BMSCs showed higher expression levels of osteogenesis-related markers (alkaline phosphatase and osteocalcin) and angiogenesis-related markers (vascular endothelial growth factor A and platelet endothelial cell adhesion molecule 1) compared to the untreated group. ICA was also found to induce osteogenesis-angiogenesis coupling of BMSCs. In the bone defect model T1DM rats, ICA facilitated bone formation and CD31hiEMCNhi type H-positive capillary formation. Lastly, ICA effectively accelerated the rate of bone formation in the defect area.

CONCLUSION

ICA was able to accelerate bone regeneration in a T1DM rat model by inducing osteogenesis-angiogenesis coupling of BMSCs.

Hammerhead-type FXR agonists induce an enhancer RNA Fincor that ameliorates nonalcoholic steatohepatitis in mice

The nuclear receptor, farnesoid X receptor (FXR/NR1H4), is increasingly recognized as a promising drug target for metabolic diseases, including nonalcoholic steatohepatitis (NASH). Protein-coding genes regulated by FXR are well known, but whether FXR also acts through regulation of long non-coding RNAs (lncRNAs), which vastly outnumber protein-coding genes, remains unknown. Utilizing RNA-seq and global run-on sequencing (GRO-seq) analyses in mouse liver, we found that FXR activation affects the expression of many RNA transcripts from chromatin regions bearing enhancer features. Among these we discovered a previously unannotated liver-enriched enhancer-derived lncRNA (eRNA), termed FXR-induced non-coding RNA (Fincor). We show that Fincor is specifically induced by the hammerhead-type FXR agonists, including GW4064 and tropifexor. CRISPR/Cas9-mediated liver-specific knockdown of Fincor in dietary NASH mice reduced the beneficial effects of tropifexor, an FXR agonist currently in clinical trials for NASH and primary biliary cholangitis (PBC), indicating that amelioration of liver fibrosis and inflammation in NASH treatment by tropifexor is mediated in part by Fincor. Overall, our findings highlight that pharmacological activation of FXR by hammerhead-type agonists induces a novel eRNA, Fincor, contributing to the amelioration of NASH in mice. Fincor may represent a new drug target for addressing metabolic disorders, including NASH.

The role of long noncoding RNAs in ocular angiogenesis and vascular oculopathy

BACKGROUND

Long noncoding RNAs (lncRNAs) are RNA transcripts over 200 nucleotides in length that do not code for proteins. Initially considered a genomic mystery, an increasing number of lncRNAs have been shown to have vital roles in physiological and pathological conditions by regulating gene expression through diverse mechanisms depending on their subcellular localization. Dysregulated angiogenesis is responsible for various vascular oculopathies, including diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, and corneal neovascularization. While anti-VEGF treatment is available, it is not curative, and long-term outcomes are suboptimal, and some patients are unresponsive. To better understand these diseases, researchers have investigated the role of lncRNAs in regulating angiogenesis and models of vascular oculopathies. This review summarizes recent research on lncRNAs in ocular angiogenesis, including the pro-angiogenic lncRNAs ANRIL, HOTAIR, HOTTIP, H19, IPW, MALAT1, MIAT, NEAT1, and TUG1, the anti-angiogenic lncRNAs MEG3 and PKNY, and the human/primate specific lncRNAs lncEGFL7OS, discussing their functions and mechanisms of action in vascular oculopathies.

Advances in secondary prevention mechanisms of macrovascular complications in type 2 diabetes mellitus patients: a comprehensive review

Type 2 diabetes mellitus (T2DM) poses a significant global health burden. This is particularly due to its macrovascular complications, such as coronary artery disease, peripheral vascular disease, and cerebrovascular disease, which have emerged as leading contributors to morbidity and mortality. This review comprehensively explores the pathophysiological mechanisms underlying these complications, protective strategies, and both existing and emerging secondary preventive measures. Furthermore, we delve into the applications of experimental models and methodologies in foundational research while also highlighting current research limitations and future directions. Specifically, we focus on the literature published post-2020 concerning the secondary prevention of macrovascular complications in patients with T2DM by conducting a targeted review of studies supported by robust evidence to offer a holistic perspective.

Recent developments in targets for ischemic foot disease

Diabetes is a key risk factor for ischaemic foot disease, which causes pain, tissue loss, hospital admission, and major amputation. Currently, treatment focuses on revascularisation, but many patients are unsuitable for surgery and revascularisation is frequently unsuccessful. The authors describe recent research in animal models and clinical trials investigating novel medical targets for ischaemia, including theories about impaired wound healing, animal models for limb ischaemia and recent randomised controlled trials testing novel medical therapies. Novel targets identified in animal models included stimulating mobilisation of CD34+ progenitor cells through upregulating oncostatin M or microRNA-181, downregulating tumour necrosis factor superfamily member 14, or activating the Wingless pathway. Within the ischaemic limb vasculature, upregulation of apolipoprotein L domain containing 1, microRNA-130b or long noncoding RNA that enhances endothelial nitric oxide synthase expression promoted limb blood supply recovery, angiogenesis, and arteriogenesis. Similarly, administration of soluble guanylate cyclase stimulators riociguat or praliciguat or 3-ketoacyl-CoA thiolase inhibitor trimetazidine promoted blood flow recovery. Translating pre-clinical findings to patients has been challenging, mainly due to limitations in clinically translatable animal models of human disease. Promising results have been reported for administering plasmids encoding hepatocyte growth factor or intra-arterial injection of bone marrow derived cells in small clinical trials. It remains to be seen whether these high resource therapies can be developed to be widely applicable. In conclusion, an ever-expanding list of potential targets for medical revascularisation is being identified. It is hoped that through ongoing research and further larger clinical trials, these will translate into new broadly applicable therapies to improve outcomes.

Hammerhead-type FXR agonists induce an eRNA FincoR that ameliorates nonalcoholic steatohepatitis in mice

The nuclear receptor, Farnesoid X Receptor (FXR/NR1H4), is increasingly recognized as a promising drug target for metabolic diseases, including nonalcoholic steatohepatitis (NASH). Protein coding genes regulated by FXR are well known, but whether FXR also acts through regulation of long non-coding RNAs (lncRNAs), which vastly outnumber protein-coding genes, remains unknown. Utilizing RNA-seq and GRO-seq analyses in mouse liver, we found that FXR activation affects the expression of many RNA transcripts from chromatin regions bearing enhancer features. Among these we discovered a previously unannotated liver-enriched enhancer-derived lncRNA (eRNA), termed FincoR. We show that FincoR is specifically induced by the hammerhead-type FXR agonists, including GW4064 and tropifexor. CRISPR/Cas9-mediated liver-specific knockdown of FincoR in dietary NASH mice reduced the beneficial effects of tropifexor, an FXR agonist currently in clinical trials for NASH and primary biliary cholangitis (PBC), indicating that that amelioration of liver fibrosis and inflammation in NASH treatment by tropifexor is mediated in part by FincoR. Overall, our findings highlight that pharmacological activation of FXR by hammerhead-type agonists induces a novel eRNA, FincoR, contributing to the amelioration of NASH in mice. FincoR may represent a new drug target for addressing metabolic disorders, including NASH.

Panax Quinquefolium Saponins enhances angiogenesis in rats with diabetes and myocardial infarction

ETHNOPHARMACOLOGICAL RELEVANCE

Xi Yang Shen (Panax quinquefolium L.) was originally recorded in "Ben Cao Cong Xin" edited by Wu Yiluo during the Qing Dynasty. Panax Quinquefolium Saponins (PQS) is the main component derived from Panax quinquefolium L, and has been wildly used in the treatment of coronary heart disease.

AIM OF THE STUDY

This study aims to explore the potential role and underlying mechanisms of PQS in promoting angiogenesis in rats with diabetes and myocardial infarction.

MATERIALS AND METHODS

Echocardiograms were used to assess cardiac function, while the heart weight to tibia length ratio was calculated to determine cardiac hypertrophy. Hematoxylin and eosin, periodic acid-Schiff and Masson's trichrome staining were used to examine cardiac morphology, myocyte diameter, and myocardial fibrosis. Immunofluorescence staining was employed to evaluate arteriolar density. The transcriptomes were analyzed and bioinformatic analyses were conducted to predict the potential angiogenesis-promoting mechanism of PQS. In addition, RT-PCR and western blotting was utilized to examine the expression of genes and proteins influenced by PQS.

RESULTS

PQS improved blood glucose, ameliorated cardiac function, reduced cardiac hypertrophy, and enhanced myocardial morphology in diabetic rats with myocardial infarction. PQS was also found to decrease myocyte diameter, curtail myocardial fibrosis, and increase arteriolar density. However, the effects of PQS were abolished following the deletion of protein kinase C δ (PKCδ). Molecular docking predicted strong interactions between the major blood components of PQS and PKCδ. Transcriptomic and bioinformatic analyses indicated that PQS may bolster angiogenesis by activating the VEGF/PI3K-Akt/eNOS pathway in rats with diabetes and myocardial infarction. Finally, the study demonstrated that PQS could inhibit the expression of PKCδ and stimulate the activation of the VEGF/PI3K-Akt/eNOS pathway.

CONCLUSIONS

PQS improves blood glucose, enhances cardiac function, mitigates cardiac damage, and boosts arteriolar density. The angiogenic impact of PQS appears to be, at least partially, due to its modulation of the PKCδ-mediated VEGF/PI3K-Akt/eNOS signaling pathway in rats with diabetes and myocardial infarction.

Plumbing mysterious RNAs in "dark genome" for the conquest of human diseases

Next-generation sequencing has revealed that less than 2% of transcribed genes are translated into proteins, with a large portion transcribed into noncoding RNAs (ncRNAs). Among these, long noncoding RNAs (lncRNAs) represent the largest group and are pervasively transcribed throughout the genome. Dysfunctions in lncRNAs have been found in various diseases, highlighting their potential as therapeutic, diagnostic, and prognostic targets. However, challenges, such as unknown molecular mechanisms and nonspecific immune responses, and issues of drug specificity and delivery present obstacles in translating lncRNAs into clinical applications. In this review, we summarize recent publications that have explored lncRNA functions in human diseases. We also discuss challenges and future directions for developing lncRNA treatments, aiming to bridge the gap between functional studies and clinical potential and inspire further exploration in the field.

Genetic Deletion of the LINC00520 Homolog in Mouse Aggravates Angiotensin II-Induced Hypertension

(1) Background: Hypertension is a complex, multifactorial disease that is caused by genetic and environmental factors. Apart from genetic predisposition, the mechanisms involved in this disease have yet to be fully understood. We previously reported that LEENE (lncRNA enhancing endothelial nitric oxide expression, transcribed from LINC00520 in the human genome) regulates endothelial cell (EC) function by promoting the expression of endothelial nitric oxide synthase (eNOS) and vascular growth factor receptor 2 (VEGFR2). Mice with genetic deletion of the LEENE/LINC00520 homologous region exhibited impaired angiogenesis and tissue regeneration in a diabetic hindlimb ischemia model. However, the role of LEENE in blood pressure regulation is unknown. (2) Methods: We subjected mice with genetic ablation of leene and wild-type littermates to Angiotensin II (AngII) and monitored their blood pressure and examined their hearts and kidneys. We used RNA-sequencing to identify potential leene-regulated molecular pathways in ECs that contributed to the observed phenotype. We further performed in vitro experiments with murine and human ECs and ex vivo experiments with murine aortic rings to validate the select mechanism. (3) Results: We identified an exacerbated hypertensive phenotype of leene-KO mice in the AngII model, evidenced by higher systolic and diastolic blood pressure. At the organ level, we observed aggravated hypertrophy and fibrosis in the heart and kidney. Moreover, the overexpression of human LEENE RNA, in part, restored the signaling pathways impaired by leene deletion in murine ECs. Additionally, Axitinib, a tyrosine kinase inhibitor that selectively inhibits VEGFR suppresses LEENE in human ECs. (4) Conclusions: Our study suggests LEENE as a potential regulator in blood pressure control, possibly through its function in ECs.

The Non-Coding RNA Journal Club: Highlights on Recent Papers-12

We are delighted to share with you our twelfth Journal Club and highlight some of the most interesting papers published recently [...].