miR-9a-5p expression is decreased in the hippocampus of rats resistant to lamotrigine: A behavioural, molecular and bioinformatics assessment

miR-9-5p is Downregulated in Serum Extracellular Vesicles of Patients Treated with Biperiden After Traumatic Brain Injury

Traumatic brain injury (TBI) is a prevalent and debilitating condition, which often leads to the development of post-traumatic epilepsy (PTE), a condition that yet lacks preventive strategies. Biperiden, an anticholinergic drug, is a promising candidate that has shown efficacy in murine models of PTE. MicroRNAs (miRNAs), small regulatory RNAs, can help in understanding the biological basis of PTE and act as TBI- and PTE-relevant biomarkers that can be detected peripherally, as they are present in extracellular vesicles (EVs) that cross the blood-brain barrier. This study aimed to investigate miRNAs in serum EVs from patients with TBI, and their association with biperiden treatment and PTE. Blood samples of 37 TBI patients were collected 10 days after trauma and treatment initiation in a double-blind clinical trial. A total of 18 patients received biperiden, with three subjects developing PTE, and 19 received placebo, with two developing PTE. Serum EVs were characterized by size distribution and protein profiling, followed by high-throughput sequencing of the EV miRNome. Differential expression analysis revealed no significant differences in miRNA expression between TBI patients with and without PTE. Interestingly, miR-9-5p displayed decreased expression in biperiden-treated patients compared to the placebo group. This miRNA regulates genes enriched in stress response pathways, including axonogenesis and neuronal death, relevant to both PTE and TBI. These findings indicate that biperiden may alter miR-9-5p expression in serum EVs, which may play a role in TBI resolution.

miRNA-137-5p improves spatial memory and cognition in Alzheimer's mice by targeting ubiquitin-specific peptidase 30

BACKGROUND

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder causing progressive dementia. Research suggests that microRNAs (miRNAs) could serve as biomarkers and therapeutic targets for AD. Reduced levels of miR-137 have been observed in the brains of AD patients, but its specific role and downstream mechanisms remain unclear. This study sought to examine the therapeutic potential of miR-137-5p agomir in alleviating cognitive dysfunction induced in AD models and explore its potential mechanisms.

METHODS

This study utilized bioinformatic analysis and a dual-luciferase reporter assay to investigate the relationship between miR-137-5p and ubiquitin-specific peptidase 30 (USP30). In vitro experiments were conducted using SH-SY5Y cells to assess the impact of miR-137-5p on Aβ1-42 neurotoxicity. In vivo experiments on AD mice evaluated the effects of miR-137-5p on cognition, Aβ1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis, as well as its influence on USP30 levels.

RESULTS

It was discovered that miR-137-5p mimics efficiently counteract Aβ1-42 neurotoxicity in SH-SY5Y cells, a protective effect that is negated by USP30 overexpression. In vivo experiments demonstrated that miR-137-5p enhances the cognition and mobility of AD mice, significantly reducing Aβ1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis within the hippocampus and cortex regions. Mechanistically, miR-137-5p significantly suppresses USP30 levels in mice, though USP30 overexpression partially buffers against miR-137-5p-induced AD symptom improvement.

CONCLUSION

Our study proposes that miR-137-5p, by instigating the downregulation of USP30, has the potential to act as a novel and promising therapeutic target for AD.

Identifying Stress-Exacerbated Thermal-Injury Induced MicroRNAs

Using a model of combat and operational stress reaction (COSR), our lab recently showed that exposure to an unpredictable combat stress (UPCS) procedure prior to a thermal injury increases pain sensitivity in male rats. Additionally, our lab has recently shown that circulating extracellular vesicle-microRNAs (EV-miRNAs), which normally function to suppress inflammation, were downregulated in a male rat model of neuropathic pain. In this current study, male and female rats exposed to UPCS, followed by thermal injury, were evaluated for changes in circulating EV-miRNAs. Adult female and male Sprague Dawley rats were exposed to a UPCS procedure for either 2 or 4 weeks. Groups consisted of the following: nonstress (NS), stress (S), NS + thermal injury (TI), and S + TI. Mechanical sensitivity was measured, and plasma was collected at baseline, throughout the UPCS exposure, and post-thermal injury. EV-miRNA isolation was performed, followed by small RNA sequencing and subsequent data analysis. UPCS exposure alone resulted in mechanical allodynia in both male and female rats at specific time points. Thermal-injury induction occurring at peak UPCS resulted in increased mechanical allodynia in the injured hind paw compared to thermal injury alone. Differential expression of the EV-miRNAs was observed between the NS and S groups as well as between NS + TI and S + TI groups. Consistent differences in EV-miRNAs are detectable in both COSR as well as during the development of mechanical sensitivity and potentially serve as key regulators, biomarkers, and targets in the treatment of COSR and thermal-injury induced mechanical sensitivity. PERSPECTIVE: This article presents the effects of unpredictable combat stress and thermal injury on EV-contained microRNAs in an animal model. These same mechanisms may exist in clinical patients and could be future prognostic and diagnostic biomarkers.