The high prevalence of gastrointestinal (GI) disorders among autism spectrum disorder (ASD) patients has prompted scientists to look into the gut microbiota as a putative trigger in ASD pathogenesis. Thus, many studies have linked the gut microbial dysbiosis that is frequently observed in ASD patients with the modulation of brain function and social behavior, but little is known about this connection and its contribution to the etiology of ASD. This present review highlights the potential role of the microbiota–gut–brain axis in autism. In particular, it focuses on how gut microbiota dysbiosis may impact gut permeability, immune function, and the microbial metabolites in autistic people. We further discuss recent findings supporting the possible role of the gut microbiome in initiating epigenetic modifications and consider the potential role of this pathway in influencing the severity of ASD. Lastly, we summarize recent updates in microbiota-targeted therapies such as probiotics, prebiotics, dietary supplements, fecal microbiota transplantation, and microbiota transfer therapy. The findings of this paper reveal new insights into possible therapeutic interventions that may be used to reduce and cure ASD-related symptoms. However, well-designed research studies using large sample sizes are still required in this area of study.

Alzheimer’s disease (AD) is a common neurodegenerative disorder that presents a significant health concern, often leading to substantial cognitive decline among older adults. A prominent feature of AD is progressive dementia, which eventually disrupts daily functioning and the ability to live independently. A major challenge in addressing AD is its prolonged pre-symptomatic phase, which makes early detection difficult. Moreover, the disease’s complexity and the inefficiency of current diagnostic methods impede the development of targeted therapies. Therefore, there is an urgent need to enhance diagnostic methodologies for detection and treating AD even before clinical symptoms appear. Exosomes are nanoscale biovesicles secreted by cells, including nerve cells, into biofluids. These exosomes play essential roles in the central nervous system (CNS) by facilitating neuronal communication and thus influencing major physiological and pathological processes. Exosomal cargo, particularly microRNAs (miRNAs), are critical mediators in this cellular communication, and their dysregulation affects various pathological pathways related to neurodegenerative diseases, including AD. This review discusses the significant roles of exosomal miRNAs in the pathological mechanisms related to AD, focusing on the promising use of exosomal miRNAs as diagnostic biomarkers and targeted therapeutic interventions for this devastating disease.

Background/Objectives: Loss of phosphatase and tensin homolog (PTEN) activity is a frequent feature of non-small-cell lung cancer (NSCLC), and epigenetic repression may contribute to its reduced expression. This study investigated the effects of 5-aza-2′-deoxycytidine (5-aza-dC) on PTEN, DNA methyltransferase 1 (DNMT1), PTEN promoter methylation-specific amplification patterns, and miR-148a-3p expression in NSCLC models. Methods: Publicly available cancer-genomics datasets were analyzed to compare PTEN and DNMT1 transcript abundance and to assess the association between PTEN methylation and transcript abundance in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). A549 and H460 cells were exposed to 2.5 or 5 µM 5-aza-dC for 72 h. Reverse-transcription quantitative PCR (RT-qPCR), Western blotting, methylation-specific PCR (MSP-PCR), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to evaluate RNA expression, protein abundance, methylation-specific amplification, and metabolic activity, respectively. Results: Bioinformatic analyses showed lower PTEN and higher DNMT1 expression in both NSCLC subtypes, together with inverse associations between PTEN methylation and transcript abundance. In both cell lines, 5-aza-dC reduced MTT metabolic activity and DNMT1 expression. PTEN mRNA and protein abundance increased significantly at 5 µM, whereas no significant changes were detected at 2.5 µM. MSP-PCR revealed persistent heterogeneous PTEN methylation-specific amplification patterns without clear evidence of progressive promoter demethylation. miR-148a-3p exhibited a biphasic response in A549 cells but remained unchanged in H460 cells. Conclusions: These findings support an association between 5-aza-dC exposure, increased PTEN expression, and reduced DNMT1 expression in NSCLC cells. Quantitative methylation analysis and mechanistic validation are required to clarify the contribution of miR-148a-3p to this regulatory association.