Suppression of MALAT1 alleviates neurocyte apoptosis and reactive oxygen species production through the miR-499-5p/SOX6 axis in subarachnoid hemorrhage

Effects of particulate air pollution exposure on lung-brain axis and related miRNAs modulation in mouse models

Particulate matter exposure is linked to numerous health issues, including respiratory, cardiovascular, and neurodegenerative diseases. This review focuses on the biological mechanisms through which air pollution influences the lung-brain axis, highlighting the role of miRNAs in regulating gene pathways affected by PM. Some microRNAs (miRNAs) are identified as key modulators of cellular processes, including inflammation, epithelial-to-mesenchymal transition (EMT), and blood-brain barrier integrity. Using mice models to study these effects allows for controlled experimentation on the systemic distribution of PM across biological barriers. Among the imaging technologies, Positron Emission Tomography is the best approach to monitor the distribution and effects of PM in vivo. The research underscores the importance of miRNA profiles as potential markers for the health effects of PM exposure, suggesting that specific miRNAs could serve as early indicators of damage to the lung-brain axis.

CircMRP4 orchestrates podocytes injury via the miR-499-5p/RRAGB/mTORC1 axis in diabetic kidney disease

Diabetic kidney disease2 (DKD) is a chronic complication of diabetes characterized by kidney damage due to persistent hyperglycemia. A growing number of evidence indicated that circular RNAs3 (circRNAs) play a crucial role in diabetes and associated complications. However, the function and mechanism of circRNAs in DKD remain unclear. Herein, we investigated the expression profiles of circRNAs in DKD mice compared to non-diabetic mice using RNA-seq analysis. A novel circRNA, circMRP4, derived from the circularization of Multidrug resistance-associated protein 44 (MRP4) was identified. The expression of circMRP4 was significantly increased in both kidney tissues of DKD and mouse podocytes exposed to high glucose5 (HG). In addition, knockdown of circMRP4 alleviated podocytes apoptosis and inflammation induced by HG, while circMRP4 overexpression resulted in the opposite impact. Dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assay demonstrated that circMRP4 could directly target miR-499-5p which was closely associated with podocytes apoptosis and inflammation. Furthermore, circMRP4 was found to act as a sponge for miR-499-5p, leading to the upregulation of its target RRAGB, thereby activating the mTORC1/P70S6K signaling. In summary, our findings suggested that circMRP4 mediated podocytes apoptosis and inflammation in DKD by modulating the miR-499-5p/RRAGB/mTORC1/P70S6K axis, highlighting circMRP4 as a potential therapeutic target for DKD.

αAsarone alleviates neuronal injury by facilitating autophagy via miR-499-5p/PDCD4/ATG5 signaling pathway in ischemia stroke

INTRODUCTION

αAsarone, an essential oil derived from Acorus gramineus Aiton, which has been successfully used to treat epilepsy in traditional chinese medicine, and has also been reported to confer neuroprotective effects on stroke. However, its mechanism of action remains poorly understood.

METHODS

The effects of αAsarone on autophagy were examined by WB, RT-qPCR, immunofluorescence colocalization, transmission electron microscope, and autophagic flux activity was measured by infecting HT22 cells with mRFP-GFP-LC3 adenovirus. And then, cells were transfected with both mimic-miR-499-5p and inhibit-miR-499-5p to investigate the role of miR-499-5p in regulating the effects of αAsarone on stroke. To further clarify the protective effect of αAsarone in vivo, TTC staining, neurological function score, H&E staining, Nissl staining, Laser speckle contrast imaging, transmission electron microscopy, immunofluorescence colocalization, WB and RT-qPCR were performed in the MCAO mice.

RESULTS

αAsarone was observed to inhibit the apoptosis of neuronal cells, and enhance autophagy. In addition, αAsarone promoted the expression of miR-499-5p. Targeting miR-499-5p can negatively regulate PDCD4 expression and the results from the dual-luciferase reporter assay demonstrate the direct targeting of PDCD4 by miR-499-5p. Promoting miR-499-5p can decrease the expression of PDCD4, increase ATG5, and enhance the protective effect of αAsarone on OGD/R injury while inhibiting miR-499-5p can weaken the effect of αAsarone. In vivo experiments further confirmed that αAsarone improved mice MCAO as evidenced by the amelioration of the neurological deficits and facilitated neuronal autophagy. Furthermore, we found that αAsarone reversed the effect of chloroquine, an autophagy inhibitor, and enhanced neuronal autophagy via miR-499-5p/PDCD4/ATG5 signaling pathway.

DISCUSSION

Our data suggest that αAsarone alleviates neuronal injury of stroke by facilitating neuronal autophagy through the miR-499-5p/PDCD4/ATG5 signaling pathway.

Interaction Between Malat1 and miR-499-5p Regulates Meis1 Expression and Function with a Net Impact on Cell Proliferation

Meis1 is a transcription factor involved in numerous functions including development and proliferation and has been previously shown to harness cell cycle progression. In this study, we used in silico analysis to predict that miR-499-5p targets Meis1 and that Malat1 sponges miR-499-5p. For the first time, we demonstrated that the overexpression of miR-499-5p led to the downregulation of Meis1 mRNA and protein in C166 cells by directly binding to its 3'UTR. Moreover, knocking down Malat1 increased miR-499-5p expression, subsequently suppressing Meis1. Through BrdU incorporation assay, we showed that the knockdown of Malat1, Meis1, or mimicking with miR-499-5p promoted cell proliferation. Enrichment analyses on proteins identified via mass spectrometry after manipulating Malat1, miR-499-5p, or Meis1 revealed a multitude of differentially expressed proteins related to cell cycle, cell division, and key pathways like Wnt and mTOR, essential for cell proliferation. Collectively, our findings confirm that Malat1 sponges miR-499-5p, regulating Meis1, and that Malat1/miR-499-5p/Meis1 could potentially form an axis that has a pivotal influence on cellular proliferation.

A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment

The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.

MiR-497-5p ameliorates the oxyhemoglobin-induced subarachnoid hemorrhage injury in vitro by targeting orthodenticle homeobox protein 1 (Otx1) to activate the Nrf2/HO-1 pathway

Subarachnoid hemorrhage (SAH) is a neurological disorder that severely damages the brain and causes cognitive impairment. MicroRNAs are critical regulators in a variety of neurological diseases. MiR-497-5p has been found to be downregulated in the aneurysm vessel walls obtained from patients with aneurysmal subarachnoid hemorrhage, but its functions and mechanisms in SAH have not been reported. Therefore, this study was designed to investigate the effect of miR-497-5p and its related mechanisms in SAH. We established an in vitro SAH model by exposing PC12 cells to oxyhemoglobin (oxyHb). We found that miR-497-5p was downregulated in SAH serum and oxyHb-treated PC12 cells, and its overexpression inhibited the oxyHb-induced apoptosis, inflammatory response and oxidative stress via activation of the Nrf2 pathway. Mechanistically, the targeting relationship between miR-497-5p and Otx1 was verified by luciferase reporter assays. Moreover, Otx1 upregulation abolished the protective effects of miR-497-5p upregulation against oxyHb-induced apoptosis, inflammation and oxidative stress in PC12 cells. Collectively, our findings indicate that miR-497-5p could inhibit the oxyHb-induced SAH damage by targeting Otx1 to activate the Nrf2/HO-1 pathway, which provides a potential therapeutic target for SAH treatment.

Systemic Inflammation after Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is one of the most severe neurological disorders, with a high mortality rate and severe disabling functional sequelae. Systemic inflammation following hemorrhagic stroke may play an important role in mediating intracranial and extracranial tissue damage. Previous studies showed that various systemic inflammatory biomarkers might be useful in predicting clinical outcomes. Anti-inflammatory treatment might be a promising therapeutic approach for improving the prognosis of patients with aSAH. This review summarizes the complicated interactions between the nervous system and the immune system.

MicroRNAs' Role in Diagnosis and Treatment of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is most commonly seen in patients over 55 years of age and often results in a loss of many productive years. SAH has a high mortality rate, and survivors often suffer from early and secondary brain injuries. Understanding the pathophysiology of the SAH is crucial in identifying potential therapeutic agents. One promising target for the diagnosis and prognosis of SAH is circulating microRNAs, which regulate gene expression and are involved in various physiological and pathological processes. In this review, we discuss the potential of microRNAs as a target for diagnosis, treatment, and prognosis in SAH.

Effect of miR-499-5p/SOX6 axis on atrial fibrosis in rats with atrial fibrillation

Atrial fibrosis is involved in the progression of atrial fibrillation (AF). miR-499-5p is the most downregulated microRNA in arrhythmogenic cardiomyopathy hearts. Sry-related high-mobility-group box 6 (SOX6) is associated with apoptosis, inflammatory responses, and fibrosis. This study investigated the mechanism of miR-499-5p in ameliorating AF rats by regulating SOX6. AF rat models were established by injecting Ach-CaCl₂ mixture, and the rats were treated with Lv-miR-499-5p/oe-SOX6/si-SOX6 before modeling. AF duration was recorded using electrocardiogram. miR-499-5p and SOX6 expression levels in the myocardium were determined by reverse transcription-quantitative polymerase chain reaction. The binding of miR-499-5p and SOX6 was validated. The atrial fibrosis degree and cardiomyocyte apoptosis were assessed using the Masson and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining methods. Levels of SOX6, atrial fibrosis markers (collage I/α-SMA/TGFβ1), cell cycle-related proteins (p21/CDC25/Cyclin B1), and cell senescence markers (SA-β-gal/γ-H2AX) were measured using Western blotting and immunohistochemistry. miR-499-5p was downregulated and SOX6 was upregulated in AF rats. miR-499-5p overexpression shortened the AF duration, alleviated atrial fibrosis, and decreased collage I/α-SMA/TGFβ1. miR-499-5p targeted SOX6 to ameliorate atrial fibrosis. AF rats exhibited increased p21/CDC25/Cyclin B1/SA-β-gal/γ-H2AX levels and raised cardiomyocyte apoptosis. SOX6 silencing downregulated p21 and alleviated cardiomyocyte cycle arrest, cell senescence, and apoptosis in AF rats. Shortly, miR-499-5p suppresses atrial fibrosis and cardiomyocyte senescence by targeting SOX6 and downregulating p21, thus mitigating AF in rats.