MicroRNA miR-181d-5p regulates the MAPK signaling pathway by targeting mitogen-activated protein kinase 8 (MAPK8) to improve lupus nephritis

Remote limb ischemic conditioning alleviates steatohepatitis via extracellular vesicle-mediated muscle-liver crosstalk

Metabolic dysfunction-associated steatohepatitis (MASH) is an advanced form of liver disease with adverse outcomes. Manipulating interorgan communication is considered a promising strategy for managing metabolic disease, including steatohepatitis. Here, we report that remote limb ischemic conditioning (RIC), a clinically validated therapy for distant organ protection by transient muscle ischemia, significantly alleviated steatohepatitis in different mouse models. The beneficial effect of limb ischemic conditioning was mediated by muscle-to-liver transfer of small extracellular vesicles (sEVs) and their cargo microRNAs, leading to elevation of miR-181d-5p in the liver. Hepatic miR-181d-5p overexpression faithfully mirrored the molecular and histological benefits of limb ischemic conditioning by suppressing nuclear receptor 4A3 (NR4A3). Furthermore, circulating EVs from human volunteers undergoing limb ischemic conditioning improved steatohepatitis and transcriptomic perturbations in primary human hepatocytes and animal models. Our data underscore the translational potential of limb ischemic conditioning for steatohepatitis management and extend our understanding of muscle-liver crosstalk.

Role of miRNAs in Apoptosis Pathways of Immune Cells in Systemic Lupus Erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by dysregulated immune responses and multi-organ involvement. Dysregulation of apoptosis, a key process for maintaining immune homeostasis, plays a critical role in the pathogenesis of SLE. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, have emerged as important modulators of apoptosis in immune cells, influencing the balance between immune tolerance and autoimmunity.

OBJECTIVES

This review aims to comprehensively summarize recent advancements in understanding the roles of miRNAs in apoptosis regulation within immune cells in SLE, highlighting their therapeutic potential for restoring immune balance and mitigating disease progression.

RESULTS

Aberrant expression of specific miRNAs contributes to the dysregulation of apoptosis in SLE immune cells. Pro-apoptotic miRNAs, such as miR-125b and miR-150, are often downregulated, leading to enhanced survival of autoreactive immune cells. Conversely, anti-apoptotic miRNAs, including miR-21, are upregulated, further disrupting the delicate balance of immune cell apoptosis. Dual-function miRNAs, such as miR-155, exhibit context-dependent roles based on cellular environments and target gene interactions. This dysregulation promotes the persistence of autoreactive immune cells and the development of autoimmunity.

CONCLUSIONS

miRNAs play critical roles in modulating apoptosis pathways, making them promising therapeutic targets for SLE. Restoring the balance of pro-apoptotic and anti-apoptotic miRNAs could help reinstate immune tolerance and reduce tissue damage. Future research should focus on elucidating miRNA targetomes, improving delivery systems, and addressing off-target effects to fully harness their therapeutic potential.

miR-193b-365 microcluster downstream of Fezf2 coordinates neuron-subtype identity and dendritic morphology in cortical projection neurons

Different neuron types develop characteristic axonal and dendritic arborizations that determine their inputs, outputs, and functions. Expression of fate-determinant transcription factors is essential for specification of their distinct identities. However, the mechanisms downstream of fate-determinant factors coordinating different aspects of neuron identity are not understood. Specifically, how distinct projection neurons develop appropriate dendritic arbors that determine their inputs is unknown. Here, we investigate this question in corticospinal and callosal projection neurons. We identified a mechanism linking the corticospinal/corticofugal identity gene Fezf2 with the regulation of dendritic development. We show that miR-193b∼365 microRNA cluster is regulated by Fezf2 and enriched in corticospinal neurons. miR-193b∼365 represses mitogen-activated protein kinase 8 (MAPK8) to regulate corticospinal dendritic development. miR-193b∼365 overexpression in callosal neurons abnormally reduces MAPK8 signal and dendritic complexity. Our findings show that regulation of MAPK8 via miR-193b∼365 cluster regulates dendritic development, providing a mechanism that coordinates projection neuron identity, specified by Fezf2, and neuron-specific dendritic morphology.

Curcumin Alleviates Arecoline-induced Oral Submucous Fibrosis via the FOSL1/MAPK8 Axis

Oral submucous fibrosis (OSF) is a precancerous lesion of the oral cavity. Areca nut consumption can cause OSF through sustained activation of buccal mucosal fibroblasts (BMFs). This study explored the effect of curcumin on arecoline-induced BMF activation and its mechanism of action. BMFs were isolated and identified by immunofluorescence detection of fibroblast surface markers vimentin and S100A4. After transfection with FOSL1- or MAPK8-related vectors, BMFs were activated by arecoline and treated with curcumin. Scratch and transwell assays were performed to detect cell migration. ChIP and luciferase reporter assays were conducted to detect the binding of FOSL1 to the MAPK8 promoter. RT-qPCR was used to detect FOSL1 and MAPK8 mRNA expression. Western blotting was used to detect FOSL1, MAPK8, COL1A1, α-SMA, Smad2, and p-Smad2 proteins. Curcumin treatment inhibited arecoline-induced fibroblast migration, reduced the expression of myofibroblast markers COL1A1, α-SMA, and p-Smad2, and downregulated the expression of FOSL1 and MAPK8. FOSL1 or MAPK8 overexpression enhanced migration and increased COL1A1, α-SMA, and p-Smad2 expression in curcumin-treated cells. FOSL1 bound to the MAPK8 promoter and promoted MAPK8 expression. Simultaneous FOSL1 overexpression and MAPK8 knockdown, compared to FOSL1 overexpression, reduced cell migration and inhibited COL1A1, α-SMA, and p-Smad2 expression. In conclusion, curcumin targets FOSL1 to reduce MAPK8 expression, thereby suppressing arecoline-induced fibroblast activation.

microRNAs in kidney diseases: Regulation, therapeutics, and biomarker potential

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play a crucial role in regulating gene expression by inhibiting the translation of their specific target messenger RNAs. To date, numerous studies have demonstrated changes in the expression of miRNAs in the kidneys throughout the progression of both acute kidney injury (AKI) and chronic kidney disease (CKD) in both human patients and experimental models. The role of specific microRNAs in the pathogenesis of kidney diseases has also been demonstrated. Further studies have elucidated the regulation of these microRNAs in diseased kidneys. Besides, certain miRNAs are detected in plasma and/or urine in kidney diseases and are potential diagnostic biomarkers. In this review, we provide an overview of recent developments in our understanding of how miRNAs contribute to kidney diseases. We also explore the potential of miRNAs as both biomarkers and therapeutic targets for these conditions, and highlight future research directions.

Inhibition of ACE2-S Protein Interaction by a Short Functional Peptide with a Boomerang Structure

Considering the high evolutionary rate and great harmfulness of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is imperative to develop new pharmacological antagonists. Human angiotensin-converting enzyme-2 (ACE2) functions as a primary receptor for the spike protein (S protein) of SARS-CoV-2. Thus, a novel functional peptide, KYPAY (K5), with a boomerang structure, was developed to inhibit the interaction between ACE2 and the S protein by attaching to the ACE2 ligand-binding domain (LBD). The inhibition property of K5 was evaluated via molecular simulations, cell experiments, and adsorption kinetics analysis. The molecular simulations showed that K5 had a high affinity for ACE2 but a low affinity for the cell membrane. The umbrella sampling (US) simulations revealed a significant enhancement in the binding potential of this functional peptide to ACE2. The fluorescence microscopy and cytotoxicity experiments showed that K5 effectively prevented the interaction between ACE2 and the S protein without causing any noticeable harm to cells. Further flow cytometry research indicated that K5 successfully hindered the interaction between ACE2 and the S protein, resulting in 78% inhibition at a concentration of 100 μM. This work offers an innovative perspective on the development of functional peptides for the prevention and therapy of SARS-CoV-2.

Role of microRNAs in Immune Regulation with Translational and Clinical Applications

MicroRNAs (miRNAs) are 19-23 nucleotide long, evolutionarily conserved noncoding RNA molecules that regulate gene expression at the post-transcriptional level. In this review, involvement of miRNAs is summarized in the differentiation and function of immune cells, in anti-infective immune responses, immunodeficiencies and autoimmune diseases. Roles of miRNAs in anticancer immunity and in the transplantation of solid organs and hematopoietic stem cells are also discussed. Major focus is put on the translational clinical applications of miRNAs, including the establishment of noninvasive biomarkers for differential diagnosis and prediction of prognosis. Patient selection and response prediction to biological therapy is one of the most promising fields of application. Replacement or inhibition of miRNAs has enormous therapeutic potential, with constantly expanding possibilities. Although important challenges still await solutions, evaluation of miRNA fingerprints may contribute to an increasingly personalized management of immune dysregulation with a remarkable reduction in toxicity and treatment side effects. More detailed knowledge of the molecular effects of physical exercise and nutrition on the immune system may facilitate self-tailored lifestyle recommendations and advances in prevention.