Dysregulation of miR-146a: a causative factor in epilepsy pathogenesis, diagnosis, and prognosis

A New Strategy for Ultrasensitive Detection Based on Target microRNA-Triggered Rolling Circle Amplification in the Early Diagnosis of Alzheimer's Disease

There is an urgent need to accurately quantify microRNA (miRNA)-based Alzheimer's disease (AD) biomarkers, which have emerged as promising diagnostic biomarkers. In this study, we present a rapid and universal approach to establishing a target miRNA-triggered rolling circle amplification (RCA) detection strategy, which achieves ultrasensitive detection of several targets, including miR-let7a-5p, miR-34a-5p, miR-206-3p, miR-9-5p, miR-132-3p, miR-146a-5p, and miR-21-5p. Herein, the padlock probe contains three repeated signal strand binding regions and a target miRNA-specific region. The target miRNA-specific region captures miRNA, and then the padlock probe is circularized with the addition of T4 DNA ligase. Subsequently, an RCA reaction is triggered, and RCA products containing multiple signal strand binding regions are generated to trap abundant fluorescein-labeled signal strands. The addition of exonuclease III (Exo III) causes signal strand digestion and leads to RCA product recycling and liberation of fluorescein. Ultimately, graphene oxide (GO) does not absorb the liberated fluorescein because of poor mutual interaction. This method exhibited high specificity, sensitivity, repeatability, and stability toward let-7a, with a detection limit of 19.35 fM and a linear range of 50 fM to 5 nM. Moreover, it showed excellent applicability for recovering miRNAs in normal human serum. Our strategy was applied to detect miRNAs in the plasma of APP/PS1 mice, demonstrating its potential in the diagnosis of miRNA-associated disease and biochemical research.

A Literature Review and Meta-Analysis on the Potential Use of miR-150 as a Novel Biomarker in the Detection and Progression of Multiple Sclerosis

BACKGROUND

MicroRNA-150 (miR-150) plays a critical role in immune regulation and has been implicated in autoimmune diseases like Multiple Sclerosis (MS). This review aims to evaluate miR-150's potential as a biomarker for MS, necessitating this review to consolidate current evidence and highlight miR-150's utility in improving diagnostic accuracy and monitoring disease progression.

METHODS

A comprehensive literature search was conducted in databases like PubMed, Scopus, Google Scholar, SciSpace, MDPI and Web of Science, adhering to PRISMA guidelines. Studies focusing on miR-150 implications in MS were included. Data extraction was conducted, while quality assessment was done using the NOS and AMSTAR 2 tools. With the extracted data a statistical analyses conducted.

RESULTS

10 eligible articles were included in review. Findings show that miR-150 levels were consistently deregulated in MS patients compared to healthy controls, correlating with disease severity and clinical parameters such as (EDSS) scores and disease activity. Additionally, miR-150 is implicated in the inflammatory pathogenesis of MS, affecting immune cell regulation and inflammatory pathways.

CONCLUSIONS

MiR-150 is a promising biomarker for MS, showing significant potential for improving diagnostic accuracy and monitoring disease progression. Its consistent deregulation in MS patients and correlation with clinical parameters underscore its clinical utility. Further research should validate miR-150's salivary presence and its possible usage as a novel biomarker and therapeutic potential in the development of MS.

Metformin improves diabetic neuropathy by reducing inflammation through up-regulating the expression of miR-146a and suppressing oxidative stress

PURPOSE

Diabetic neuropathy (DN) is a notable complication of diabetes mellitus. The potential involvement of miR-146a in DN regulation is presently under investigation. Metformin, a commonly prescribed medication for diabetes, is the primary therapeutic intervention. This study aimed to unveil the potential protective effects of metformin on diabetic neuropathy and explore the mechanisms underlying its action.

METHOD

Six-weeks male Sprague Dawley rats (n = 40) were randomly divided into 5 groups. The rat model of diabetic neuropathy (DN) was established by administering streptozotocin (STZ). To investigate the effects on the sciatic nerve and resident Schwann cells (RSCs), metformin and miR-146a mimics were administered, and our research explored the potential underlying mechanism.

RESULT

The sciatic nerve samples obtained from diabetic rats exhibited noticeable morphological damage, accompanied by decreased miR-146a expression (2.61 ± 0.11 vs 5.0 ± 0.3, p < 0.01) and increased inflammation levels (p65: 1.89 ± 0.04 vs 0.82 ± 0.05, p < 0.01; TNF-α: 0.93 ± 0.03 vs 0.33 ± 0.03, p < 0.01). Notably, the administration of metformin effectively ameliorated the structural alterations in the sciatic nerve by suppressing the inflammatory pathway (p65: 1.15 ± 0.05 vs 1.89 ± 0.04, p < 0.01; TNF-α: 0.67 ± 0.04 vs 0.93 ± 0.03, p < 0.01) and reducing oxidative stress (NO: 0.062 ± 0.004 vs 0.154 ± 0.004umol/mg, p < 0.01; SOD: 3.08 ± 0.09 vs 2.46 ± 0.09 U/mg, p < 0.01). The miR-146a mimics intervention group exhibited comparable findings.

CONCLUSION

This study's findings implied that metformin can potentially mitigate diabetic neuropathy in rats through the modulation of miR-146a expression.

Non-coding RNAs and neuroinflammation: implications for neurological disorders

Neuroinflammation is considered a balanced inflammatory response important in the intrinsic repair process after injury or infection. Under chronic states of disease, injury, or infection, persistent neuroinflammation results in a heightened presence of cytokines, chemokines, and reactive oxygen species that result in tissue damage. In the CNS, the surrounding microglia normally contain macrophages and other innate immune cells that perform active immune surveillance. The resulting cytokines produced by these macrophages affect the growth, development, and responsiveness of the microglia present in both white and gray matter regions of the CNS. Controlling the levels of these cytokines ultimately improves neurocognitive function and results in the repair of lesions associated with neurologic disease. MicroRNAs (miRNAs) are master regulators of the genome and subsequently control the activity of inflammatory responses crucial in sustaining a robust and acute immunological response towards an acute infection while dampening pathways that result in heightened levels of cytokines and chemokines associated with chronic neuroinflammation. Numerous reports have directly implicated miRNAs in controlling the abundance and activity of interleukins, TGF-B, NF-kB, and toll-like receptor-signaling intrinsically linked with the development of neurological disorders such as Parkinson's, ALS, epilepsy, Alzheimer's, and neuromuscular degeneration. This review is focused on discussing the role miRNAs play in regulating or initiating these chronic neurological states, many of which maintain the level and/or activity of neuron-specific secondary messengers. Dysregulated miRNAs present in the microglia, astrocytes, oligodendrocytes, and epididymal cells, contribute to an overall glial-specific inflammatory niche that impacts the activity of neuronal conductivity, signaling action potentials, neurotransmitter robustness, neuron-neuron specific communication, and neuron-muscular connections. Understanding which miRNAs regulate microglial activation is a crucial step forward in developing non-coding RNA-based therapeutics to treat and potentially correct the behavioral and cognitive deficits typically found in patients suffering from chronic neuroinflammation.

MiR-324-5p inhibition after intrahippocampal kainic acid-induced status epilepticus does not prevent epileptogenesis in mice

Background

Acquired epilepsies are caused by an initial brain insult that is followed by epileptogenesis and finally the development of spontaneous recurrent seizures. The mechanisms underlying epileptogenesis are not fully understood. MicroRNAs regulate mRNA translation and stability and are frequently implicated in epilepsy. For example, antagonism of a specific microRNA, miR-324-5p, before brain insult and in a model of chronic epilepsy decreases seizure susceptibility and frequency, respectively. Here, we tested whether antagonism of miR-324-5p during epileptogenesis inhibits the development of epilepsy.

Methods

We used the intrahippocampal kainic acid (IHpKa) model to initiate epileptogenesis in male wild type C57BL/6 J mice aged 6-8 weeks. Twenty-four hours after IHpKa, we administered a miR-324-5p or scrambled control antagomir intracerebroventricularly and implanted cortical surface electrodes for EEG monitoring. EEG data was collected for 28 days and analyzed for seizure frequency and duration, interictal spike activity, and EEG power. Brains were collected for histological analysis.

Results

Histological analysis of brain tissue showed that IHpKa caused characteristic hippocampal damage in most mice regardless of treatment. Antagomir treatment did not affect latency to, frequency, or duration of spontaneous recurrent seizures or interictal spike activity but did alter the temporal development of frequency band-specific EEG power.

Conclusion

These results suggest that miR-324-5p inhibition during epileptogenesis induced by status epilepticus does not convey anti-epileptogenic effects despite having subtle effects on EEG frequency bands. Our results highlight the importance of timing of intervention across epilepsy development and suggest that miR-324-5p may act primarily as a proconvulsant rather than a pro-epileptogenic regulator.