LncRNA MALAT1 Aggravates Renal Tubular Injury via Activating LIN28A and the Nox4/AMPK/mTOR Signaling Axis in Diabetic Nephropathy

LncRNA MALAT1 as a potential diagnostic and therapeutic target in kidney diseases

Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript1 (MALAT1) has emerged as a crucial biomarker and therapeutic target for kidney diseases, including acute kidney injury (AKI), chronic kidney disease (CKD), diabetic kidney disease (DKD), lupus nephritis (LN), and renal cell carcinoma (RCC). LncRNAs are non-coding RNAs that have more than 200 nucleotides that play a crucial role in gene regulation at the post-translational stage, transcriptional, and epigenetic levels. LncRNA MALAT1 regulates gene expression and modulates cellular functions such as proliferation, inflammation, apoptosis, and fibrosis, which are key pathophysiology of kidney diseases. Overexpression of lncRNA MALAT1 has been consistently observed in kidney tissue, correlating with the severity and progression of kidney disease. In AKI, lncRNA MALAT1 exacerbates inflammation and tissue damage, contributing to disease progression. In CKD and DKD, lncRNA MALAT1 is implicated in the regulation of fibrosis by modulating key pathways, including focal adhesion kinase (FAK), toll-like receptor 4 (TLR4), NOD-like receptor protein3 (NLRP3), and nuclear factor kappa B (NF-κB), play pivotal roles in promoting disease progression. In LN, lncRNA MALAT1 has been linked to immune regulation and kidney damage, while in RCC, its role in promoting tumor growth and metastasis has been well documented. Preclinical research has demonstrated that therapeutic strategies targeting lncRNA MALAT1, such as knockdown and knockout, can reduce inflammation and fibrosis while improving kidney function. The fundamental role of lncRNA MALAT1 in kidney disease progression is yet to be fully understood. However, lncRNA MALAT1 has shown promise as a biomarker and therapeutic target to mitigate kidney disease development. This review highlights the potential of lncRNAs MALAT1 as diagnostic biomarkers and therapeutic targets, offering insights into a comprehensive approach to managing kidney diseases in the future.

MiR-92a-3p Promotes Renal Injury and Fibrosis Through Facilitating M1 Macrophage Polarization via Targeting LIN28A

Infiltrated and activated M1 macrophages play a role in kidney injury and fibrosis during chronic kidney disease (CKD) progression. However, the specific ways that M1 macrophage polarization contributes to renal fibrosis are not fully understood. The study seeks to investigate how miR-92a-3p regulates M1 macrophage polarization and its connection to renal fibrosis in the development of CKD. Our results revealed that miR-92a-3p overexpression increased M1-macrophage activation, iNOS, IL-6, and TNF-alpha expression in RAW264.7 upon LPS stimulation. LIN28A overexpression reversed these effects. Moreover, miR-92a-3p overexpression in RAW264.7 exacerbated NRK-52E cell apoptosis induced by LPS, but LIN28A overexpression counteracted this effect. MiR-92a-3p knockout in unilateral ureteral obstruction (UUO) C57BL/6 mice led to reduced renal infiltration and fibrosis, accompanied by decreased iNOS, alpha-SMA, IL-6, TNF-alpha, and increased LIN28A. In summary, our findings suggest that miR-92a-3p may play a role in promoting renal injury and fibrosis both in vitro and in vivo. This effect is potentially achieved by facilitating M1 macrophage polarization through the targeting of LIN28A.

MiR-92a-3p Knockdown Attenuates Transforming Growth Factor-β1-induced Tubulointerstitial Fibrosis by Targeting LIN28A-mediated EMT Pathway

ABSTRACT

The role of microRNAs in regulating tubulointerstitial fibrosis, a key feature of progressive chronic kidney disease, is of significant importance. LIN28A has been reported to attenuate renal fibrosis in obstructive nephropathy. Here, our objective was to investigate the precise biological function of the miR-92a-3p/LIN28A axis in tubulointerstitial fibrosis. The human renal proximal tubular epithelial (HK-2) cell line was exposed to transforming growth factor (TGF)-β1, establishing an in vitro model mimicking tubulointerstitial fibrosis. Luciferase reporter assay was utilized to investigate the relationship between miR-92a-3p and LIN28A. Cell transfection techniques were employed to modify the expression of miR-92a-3p and LIN28A. An in vivo model of tubulointerstitial fibrosis was created by inducing unilateral ureteral obstruction (UUO) in C57BL/6N mice. Our initial observations showed that TGF-β1 treatment of HK-2 cells and the UUO mice model led to an increase in miR-92a-3p expression and a decrease in LIN28A expression. We confirmed that miR-92a-3p directly targeted LIN28A in HK-2 cells. In TGF-β1-stimulated HK-2 cells, knocking down miR-92a-3p notably reduced the levels of alpha smooth muscle actin and vimentin and concurrently enhanced the expression of E-cadherin. These changes were counteracted upon transfection with si-LIN28A. Thus, directing interventions toward miR-92a-3p holds the potential to emerge as a viable therapeutic approach for addressing tubulointerstitial fibrosis.

The role of long non-coding RNAs in the development of diabetic kidney disease and the involved clinical application

Diabetic kidney disease (DKD), one of the common microvascular complications of diabetes, is increasing in prevalence worldwide and can lead to End-stage renal disease. However, there are still gaps in our understanding of the pathophysiology of DKD, and both current clinical diagnostic methods and treatment strategies have drawbacks. According to recent research, long non-coding RNAs (lncRNAs) are intimately linked to the developmental process of DKD and could be viable targets for clinical diagnostic decisions and therapeutic interventions. Here, we review recent insights gained into lncRNAs in pathological changes of DKD such as mesangial expansion, podocyte injury, renal tubular injury, and interstitial fibrosis. We also discuss the clinical applications of DKD-associated lncRNAs as diagnostic biomarkers and therapeutic targets, as well as their limitations and challenges, to provide new methods for the prevention, diagnosis, and treatment of DKD.

Depression of LncRNA DANCR alleviates tubular injury in diabetic nephropathy by regulating KLF5 through sponge miR-214-5p

OBJECTIVE

Diabetic nephropathy (DN) manifests a critical aspect in the form of renal tubular injury. The current research aimed to determine the function and mechanism of long non-coding ribonucleic acid (LncRNA) differentiation antagonising non-protein coding RNA (DANCR), with a focus on its impact on renal tubular injury.

METHODS

Quantitative reverse transcription polymerase chain reaction was employed to analyze the RNA levels of DANCR in the serum of patients with DN or human proximal tubular epithelial cells (human kidney 2 [HK2]). The diagnostic significance of DANCR was assessed using a receiver operating characteristic curve. A DN model was established by inducing HK-2 cells with high glucose (HG). Cell proliferation, apoptosis, and the levels of inflammatory factors, reactive oxygen species (ROS), and malondialdehyde (MDA) were detected using the Cell Counting Kit - 8, flow cytometry, and enzyme-linked immunosorbent assay. The interaction between microRNA (miR)-214-5p and DANCR or Krüppel-like factor 5 (KLF5) was investigated using RNA immunoprecipitation and dual-luciferase reporter assays.

RESULTS

Elevated levels of DANCR were observed in the serum of patients with DN and HG-inducted HK-2 cells (P < 0.05). DANCR levels effectively identified patients with DN from patients with type 2 diabetes mellitus. Silencing of DANCR protected against HG-induced tubular injury by restoring cell proliferation, inhibiting apoptosis, and reducing the secretion of inflammatory factors and oxidative stress production (P < 0.05). DANCR functions as a sponge for miR-214-5p, and the mitigation of DANCR silencing on HG-induced renal tubular injury was partially attenuated with reduced miR-214-5p (P < 0.05). Additionally, KLF5 was identified as the target of miR-214-5p.

CONCLUSION

DANCR was identified as diagnostic potential for DN and the alleviation of renal tubular injury via the miR-214-5p/KLF5 axis, following DANCR silencing, introduces a novel perspective and approach to mitigating DN.

Long non-coding RNA-targeting therapeutics: discovery and development update

INTRODUCTION

lncRNAs are major players in regulatory networks orchestrating multiple cellular functions, such as 3D chromosomal interactions, epigenetic modifications, gene expression and others. Due to progress in the development of nucleic acid-based therapeutics, lncRNAs potentially represent easily accessible therapeutic targets.

AREAS COVERED

Currently, significant efforts are directed at studies that can tap the enormous therapeutic potential of lncRNAs. This review describes recent developments in this field, particularly focusing on clinical applications.

EXPERT OPINION

Extensive druggable target range of lncRNA combined with high specificity and accelerated development process of nucleic acid-based therapeutics open new prospects for treatment in areas of extreme unmet medical need, such as genetic diseases, aggressive cancers, protein deficiencies, and subsets of common diseases caused by known mutations. Although currently wide acceptance of lncRNA-targeting nucleic acid-based therapeutics is impeded by the need for parenteral or direct-to-CNS administration, development of less invasive techniques and orally available/BBB-penetrant nucleic acid-based therapeutics is showing early successes. Recently, mRNA-based COVID-19 vaccines have demonstrated clinical safety of all aspects of nucleic acid-based therapeutic technology, including multiple chemical modifications of nucleic acids and nanoparticle delivery. These trends position lncRNA-targeting drugs as significant players in the future of drug development, especially in the area of personalized medicine.

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study

Epigenetics regulates gene expression and has been confirmed to play a critical role in a variety of metabolic diseases, such as diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), osteoporosis, gout, hyperthyroidism, hypothyroidism and others. The term 'epigenetics' was firstly proposed in 1942 and with the development of technologies, the exploration of epigenetics has made great progresses. There are four main epigenetic mechanisms, including DNA methylation, histone modification, chromatin remodelling, and noncoding RNA (ncRNA), which exert different effects on metabolic diseases. Genetic and non-genetic factors, including ageing, diet, and exercise, interact with epigenetics and jointly affect the formation of a phenotype. Understanding epigenetics could be applied to diagnosing and treating metabolic diseases in the clinic, including epigenetic biomarkers, epigenetic drugs, and epigenetic editing. In this review, we introduce the brief history of epigenetics as well as the milestone events since the proposal of the term 'epigenetics'. Moreover, we summarise the research methods of epigenetics and introduce four main general mechanisms of epigenetic modulation. Furthermore, we summarise epigenetic mechanisms in metabolic diseases and introduce the interaction between epigenetics and genetic or non-genetic factors. Finally, we introduce the clinical trials and applications of epigenetics in metabolic diseases.

The role of lncRNAs in regulation of DKD and diabetes-related cancer

Diabetes mellitus often results in several complications, such as diabetic kidney disease (DKD) and end-stage renal diseases (ESRDs). Cancer patients often have the dysregulated glucose metabolism. Abnormal glucose metabolism can enhance the tumor malignant progression. Recently, lncRNAs have been reported to regulate the key proteins and signaling pathways in DKD development and progression and in cancer patients with diabetes. In this review article, we elaborate the evidence to support the function of lncRNAs in development of DKD and diabetes-associated cancer. Moreover, we envisage that lncRNAs could be diagnosis and prognosis biomarkers for DKD and cancer patients with diabetes. Furthermore, we delineated that targeting lncRNAs might be an alternative approach for treating DKD and cancer with dysregulated glucose metabolism.