Involvement of the miR-363-5p/P2RX4 Axis in Regulating Schwann Cell Phenotype after Nerve Injury

Hmgcs2 is the hub gene in diabetic cardiomyopathy and is negatively regulated by Hmgcs2, promoting high glucose-induced cardiomyocyte injury

BACKGROUND

Diabetic cardiomyopathy (DCM) represents a major cause of heart failure and a large medical burden worldwide. This study screened the potentially regulatory targets of DCM and analyzed their roles in high glucose (HG)-induced cardiomyocyte injury.

METHODS

Through GEO database, we obtained rat DCM expression chips and screened differentially expressed genes. Rat cardiomyocytes (H9C2) were induced with HG. 3-hydroxy-3-methylglutarylcoenzyme A synthase 2 (Hmgcs2) and microRNA (miR)-363-5p expression patterns in cells were measured by real-time quantitative polymerase chain reaction or Western blot assay, with the dual-luciferase assay to analyze their binding relationship. Then, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, lactate dehydrogenase assay, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, enzyme-linked immunosorbent assay, and various assay kits were applied to evaluate cell viability, cytotoxicity, apoptosis, inflammation responses, and oxidative burden.

RESULTS

Hmgcs2 was the vital hub gene in DCM. Hmgcs2 was upregulated in HG-induced cardiomyocytes. Hmgcs2 downregulation increased cell viability, decreased TUNEL-positive cell number, reduced HG-induced inflammation and oxidative stress. miR-363-5p is the upstream miRNA of Hmgcs2. miR-363-5p overexpression attenuated HG-induced cell injury.

CONCLUSIONS

Hmgcs2 had the most critical regulatory role in DCM. We for the first time reported that miR-363-5p inhibited Hmgcs2 expression, thereby alleviating HG-induced cardiomyocyte injury.

Loss of TDP-43 mediates severe neurotoxicity by suppressing PJA1 gene transcription in the monkey brain

The nuclear loss and cytoplasmic accumulation of TDP-43 (TAR DNA/RNA binding protein 43) are pathological hallmarks of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Previously, we reported that the primate-specific cleavage of TDP-43 accounts for its cytoplasmic mislocalization in patients' brains. This prompted us to investigate further whether and how the loss of nuclear TDP-43 mediates neuropathology in primate brain. In this study, we report that TDP-43 knockdown at the similar effectiveness, induces more damage to neuronal cells in the monkey brain than rodent mouse. Importantly, the loss of TDP-43 suppresses the E3 ubiquitin ligase PJA1 expression in the monkey brain at transcriptional level, but yields an opposite upregulation of PJA1 in the mouse brain. This distinct effect is due to the species-dependent binding of nuclear TDP-43 to the unique promoter sequences of the PJA1 genes. Further analyses reveal that the reduction of PJA1 accelerates neurotoxicity, whereas overexpressing PJA1 diminishes neuronal cell death by the TDP-43 knockdown in vivo. Our findings not only uncover a novel primate-specific neurotoxic contribution to the loss of function theory of TDP-43 proteinopathy, but also underscore a potential therapeutic approach of PJA1 to the loss of nuclear TDP-43.

Schwann Cell-Derived Exosomal Vesicles: A Promising Therapy for the Injured Spinal Cord

Exosomes are nanoscale-sized membrane vesicles released by cells into their extracellular milieu. Within these nanovesicles reside a multitude of bioactive molecules, which orchestrate essential biological processes, including cell differentiation, proliferation, and survival, in the recipient cells. These bioactive properties of exosomes render them a promising choice for therapeutic use in the realm of tissue regeneration and repair. Exosomes possess notable positive attributes, including a high bioavailability, inherent safety, and stability, as well as the capacity to be functionalized so that drugs or biological agents can be encapsulated within them or to have their surface modified with ligands and receptors to imbue them with selective cell or tissue targeting. Remarkably, their small size and capacity for receptor-mediated transcytosis enable exosomes to cross the blood-brain barrier (BBB) and access the central nervous system (CNS). Unlike cell-based therapies, exosomes present fewer ethical constraints in their collection and direct use as a therapeutic approach in the human body. These advantageous qualities underscore the vast potential of exosomes as a treatment option for neurological injuries and diseases, setting them apart from other cell-based biological agents. Considering the therapeutic potential of exosomes, the current review seeks to specifically examine an area of investigation that encompasses the development of Schwann cell (SC)-derived exosomal vesicles (SCEVs) as an approach to spinal cord injury (SCI) protection and repair. SCs, the myelinating glia of the peripheral nervous system, have a long history of demonstrated benefit in repair of the injured spinal cord and peripheral nerves when transplanted, including their recent advancement to clinical investigations for feasibility and safety in humans. This review delves into the potential of utilizing SCEVs as a therapy for SCI, explores promising engineering strategies to customize SCEVs for specific actions, and examines how SCEVs may offer unique clinical advantages over SC transplantation for repair of the injured spinal cord.

MicroRNA: Crucial modulator in purinergic signalling involved diseases

Both microRNAs (miRNAs) and purinergic signalling are widely and respectively expressed in various tissues of different organisms and play vital roles in a variety of physiological and pathological processes. Here, we reviewed the current publications contributed to the relationship of miRNAs and purinergic signalling in cardiovascular diseases, gastrointestinal diseases, neurological diseases, and ophthalmic diseases. We tried to decode the miRNAs-purinergic signalling network of purinergic signalling involved diseases. The evidence indicated that more than 30 miRNAs (miR-22, miR-30, miR-146, miR-150, miR-155, miR-187, etc.) directly or indirectly modulate P1 receptors (A₁, A_2A, A_2B, A₃), P2 receptors (P2X1, P2X3, P2X4, P2X7, P2Y2, P2Y6, P2Y12), and ecto-enzymes (CD39, CD73, ADA2); P2X7 and CD73 could be modulated by multiple miRNAs (P2X7: miR-21, miR-22, miR-30, miR-135a, miR-150, miR-186, miR-187, miR-216b; CD73: miR-141, miR-101, miR-193b, miR-340, miR-187, miR-30, miR-422a); miR-187 would be the common miRNA to modulate P2X7 and CD73.

Tissue-engineered in vitro modeling of the impact of Schwann cells in amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease affecting upper and lower motor neurons (MN). To investigate whether Schwann cells could be involved in the disease pathogenesis, we developed a tissue-engineered 3D in vitro model that combined MNs cocultured with astrocytes and microglia seeded on top of a collagen sponge populated with epineurium fibroblasts to enable 3D axonal migration. C2C12 myoblasts were seeded underneath the sponge in presence or absence of Schwann cells. To reproduce an ALS cellular microenvironment, MNs, astrocytes and microglia were extracted from SOD1^G93A mice recapitulating many aspects of the human disease. This 3D ALS in vitro model was compared with a 3D control made of cells isolated from SOD1^WT mice. We showed that normal Schwann cells strongly enhanced MN axonal migration in the 3D control model but had no effect in the ALS model. However, ALS-derived Schwann cells isolated from SOD1^G93A mice failed to significantly improve axonal migration in both models. These results suggest that a cell therapy using healthy Schwann cells may not be effective in promoting axonal regeneration in ALS. In addition, this 3D ALS model could be used to study the impact of other cell types on ALS by various combinations of normal and diseased cells. This article is protected by copyright. All rights reserved.

A Double-Negative Feedback Interaction between miR-21 and PPAR-α in Clear Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the main histotype of kidney cancer, which is typically highly resistant to conventional therapies and known for abnormal lipid accumulation. In this context, we focused our attention on miR-21, an oncogenic miRNA overexpressed in ccRCC, and peroxysome proliferator-activated receptor-α (PPAR- α), one master regulator of lipid metabolism targeted by miR-21. First, in a cohort of 52 primary ccRCC samples, using RT-qPCR and immunohistochemistry, we showed that miR-21 overexpression was correlated with PPAR-α downregulation. Then, in ACHN and 786-O cells, using RT-qPCR, the luciferase reporter gene, chromatin immunoprecipitation, and Western blotting, we showed that PPAR-α overexpression (i) decreased miR-21 expression, AP-1 and NF-κB transcriptional activity, and the binding of AP-1 and NF-κB to the miR-21 promoter and (ii) increased PTEN and PDCD4 expressions. In contrast, using pre-miR-21 transfection, miR-21 overexpression decreased PPAR-α expression and transcriptional activity mediated by PPAR-α, whereas the anti-miR-21 (LNA-21) strategy increased PPAR-α expression, but also the expression of its targets involved in fatty acid oxidation. In this study, we showed a double-negative feedback interaction between miR-21 and PPAR-α. In ccRCC, miR-21 silencing could be therapeutically exploited to restore PPAR-α expression and consequently inhibit the oncogenic events mediated by the aberrant lipid metabolism of ccRCC.