👤 Mohit Mazumder

The gut microbiome and the central nervous system are intricately connected through a bidirectional communication system that plays a vital role in maintaining gut homeostasis and overall health. Disruptions in this interaction are linked to gastrointestinal and neuropsychiatric disorders, including anxiety. This review aims to provide a comprehensive analysis of the gut microbiota's role in anxiety and evaluate the therapeutic potential of prebiotics. This review synthesizes recent literature from databases including PubMed, Scopus, Web of Science, and Google Scholar, focusing on the gut microbiota's role in anxiety and the therapeutic potential of prebiotics. The microbiota-gut-brain axis communicates through multiple pathways, including the vagus nerve, immune signaling, microbial metabolites, and the hypothalamic-pituitary-adrenal (HPA) axis. Prebiotics modulate these pathways by enhancing beneficial microbial populations and influencing the production of neuroactive compounds. Key molecular targets implicated in this communication include brain-derived neurotrophic factor (BDNF), glucocorticoid receptors, and shortchain fatty acids, which modulate neurotransmitters such as GABA and serotonin, and influence neuroinflammatory pathways implicated in anxiety pathophysiology. The findings highlight the immunological, neurochemical, and endocrine mechanisms through which the gut microbiota interacts with neurophysiological systems. These mechanisms underscore the pharmacological potential of prebiotics in the management of psychiatric illnesses. The interplay between the gastrointestinal microbiota and neurophysiological systems provides key pharmacological insights into the potential of prebiotics as a therapeutic approach for managing psychiatric illnesses, detailing their mechanistic pathways and translational applications in clinical practice. Show less

Dementia, marked by a decline in mental abilities like memory that interferes with daily life, is primarily caused by Alzheimer's Disease (AD). Symplocos racemosa, rich in acetyl oleanolic acid, serves as a neuroprotective agent by lowering amyloid β levels in the brain. This study aims to develop a nanoemulsion for the targeted delivery of S. racemosa phytoconstituents to enhance therapeutic efficacy against dementia. The study also aims to find out the mechanism of the responsible molecules via molecular docking studies. S. racemosa bark was ultrasonically extracted with methanol and ethyl acetate, yielding six phytoconstituents: ellagic acid, betulinic acid, acetyl oleanolic acid, salireposide (from methanol), oleanolic acid, symlocoside (from ethyl acetate), isolated by column chromatography. Molecular docking against AChE and BACE-1 was conducted using CB Dock-2. A chitosan- based nanoemulsion containing all six compounds was prepared to enhance brain delivery and was physically characterized. All isolated phytoconstituents and nanoemulsions were evaluated for their in vitro enzyme inhibition (AChE and BACE-1) potential. Its anti-dementia efficacy was evaluated in scopolamine-induced rodent models using Hebb-Williams and Elevated Plus Maze tests, complemented by histopathological analysis of the brain cortex to assess therapeutic effects. Docking studies showed acetyl oleanolic acid had stronger binding to BACE-1 and AChE than donepezil. This was further supported by an in vitro enzyme inhibition assay. Nanoemulsion at 200 and 400 mg/kg significantly reduced the time taken by memory-impaired mice to complete the Hebb-Williams Maze and transfer latency in the Elevated Plus Maze. Histopathological analysis showed a significant recovery of cortical damage. This indicates that the nanoemulsion has strong potential for the treatment of Alzheimer 's-related neurodegeneration. The neuroprotective action of S. racemosa nanoemulsion (SRMN) is attributed to the large-scale presence of its phytoconstituents, which reportedly exhibit a better binding affinity and inhibitory action against AChE and BACE-1 than donepezil. Additionally, the nanoemulsion enhanced bioavailability, stability, and blood-brain barrier penetration, which in turn improved therapeutic outcomes. From behavioral and histological studies, we observed that SRMN performed well in terms of memory improvement and cortical protection, suggesting that it is a very good multi-target approach for dementia. The prepared nanoemulsion from S. racemosa's isolated phytoconstituents is reported to exhibit synergistic action, thereby effectively managing dementia through BACE-1 and AChE inhibition. Show less

Double-strand breaks (DSBs) threaten genomic stability and need immediate attention from DNA damage response (DDR) machinery involved in homologous recombination (HR) or nonhomologous end joining (NHEJ). DDR in heterochromatin is challenging owing to the distinct chromatin organization. Heterochromatin protein 1 (HP1) isoforms are central to heterochromatin structure and have been implicated in DDR. Mammalian HP1 has three isoforms, HP1α, HP1β, and HP1γ, which possess significant homology and yet have distinct functions. HP1α is the only isoform known to undergo liquid-liquid phase separation mediated by phosphorylation on the N-terminal extension (NTE). We show that the minute-scale dynamics of HP1α and HP1β differ dramatically and differentially influence the recruitment of HR vs. NHEJ factors at sites of laser-induced clustered DSBs. Perturbing HP1α phosphorylation impairs HR factor recruitment and reduces HR efficiency. Our study provides a potential link between phase separation and DDR-centric roles of HP1α and hints at spatial partitioning of repair pathways in response to damage in heterochromatin. Show less

Modulation of cell signaling pathways is the key area of research towards the treatment of neurodegenerative disorders. Altered Nrf2-Keap1-ARE (Nuclear factor erythroid-2-related factor 2-Kelch-like ECH-associated protein 1-Antioxidant responsive element) and SIRT1 (Sirtuin 1) cell signaling pathways are considered to play major role in the etiology and pathogenesis of Alzheimer's disease (AD) and Parkinson's disease (PD). Strikingly, betanin, a betanidin 5-O-β-D-glucoside compound is reported to show commendable anti-oxidative, anti-inflammatory and anti-apoptotic effects in several disease studies including AD and PD. The present review discusses the pre-clinical studies demonstrating the neuroprotective effects of betanin by virtue of its potential to ameliorate oxidative stress, neuroinflammation, abnormal protein aggregation and cell death. It highlights the direct linkage between the neuroprotective abilities of betanin and upregulation of the Nrf2-Keap1-ARE and SIRT1 signaling pathways. The review further hypothesizes the involvement of the betanin-Nrf2-ARE route in the inhibition of beta-amyloid aggregation through beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), one of the pivotal hallmarks of AD. The present review hereby for the first time elaborately discusses the reported neuroprotective abilities of betanin and decodes the Nrf2 and SIRT1 modulating potential of betanin as a primary mechanism of action behind, hence highlighting it as a novel drug candidate for the treatment of neurodegenerative diseases in the near future. Show less

Malaria is a life-threatening disease, and Africa is still one of the most affected endemic regions despite years of policy to limit infection and transmission rates. Further, studies into the variable efficacy of the vaccine are needed to provide a better understanding of protective immunity. Thus, the current study is designed to delineate the effect of each dose of vaccine on the transcriptional profiles of subjects to determine its efficacy and understand the molecular mechanisms underlying the protection this vaccine provides. Here, we used gene expression profiles of pre and post-vaccination patients after various doses of RTS,S based on samples collected from the Gene Expression Omnibus datasets. Subsequently, differential gene expression analysis using edgeR revealed the significantly (false discovery rate < 0.005) 158 downregulated and 61 upregulated genes between control vs. controlled human malaria infection samples. Further, enrichment analysis of significant genes delineated the involvement of CCL8, CXCL10, CXCL11, XCR1, CSF3, IFNB1, IFNE, IL12B, IL22, IL6, IL27, etc., genes which found to be upregulated after earlier doses but downregulated after the 3rd dose in cytokine-chemokine pathways. Notably, we identified 13 cytokine genes whose expression significantly varied during three doses. Eventually, these findings give insight into the dual role of cytokine responses in malaria pathogenesis. The variations in their expression patterns after various doses of vaccination are linked to the protection as it decreases the severe inflammatory effects in malaria patients. This study will be helpful in designing a better vaccine against malaria and understanding the functions of cytokine response as well. Show less