👤 Yeshwanth Mahesh

Alzheimer's disease (AD) is the most prevalent form of dementia, accounting for more than two-thirds of cases in older adults. AD is associated with neuropsychiatric symptoms such as depression, anxiety, and sleep disturbances. The coexistence of AD with depression, in particular, poses serious challenges and often results in suboptimal outcomes with conventional therapies. The present study therefore aimed to investigate the therapeutic potential of escitalopram (ESC; SSRI) in combination with galantamine (GAL; AChE inhibitor) on key pathological pathways, including the neurotrophic system, hypothalamic-pituitary-adrenal (HPA) axis, kynurenine pathway, inflammation, and oxidative stress, in an animal model of AD comorbid with depression. Swiss albino mice were subjected to chronic mild stress (CMS) for 21 days and received intrahippocampal administration of amyloid-β peptide to mimic AD-depression comorbidity. Subsequently, ESC (10 mg/kg) combined with GAL (5 mg/kg) was administered orally for 20 days alongside the CMS protocol, followed by behavioral, biochemical, and histopathological assessments. The combined GAL + ESC treatment significantly alleviated depressive symptoms and improved working and spatial memory in CMS and amyloid-β-exposed mice. Furthermore, the therapy normalized hippocampal levels of BDNF, proinflammatory cytokines (IL-6, TNF-α), kynurenine metabolites (3-HK, QUIN), and oxidative stress markers toward those observed in the sham group. Histopathological analysis further confirmed the preservation of hippocampal integrity with combined therapy. Overall, the findings highlight the potential of ESC as an adjunct to GAL in ameliorating depressive symptoms and cognitive deficits, underscoring its promise for further clinical evaluation in the management of AD comorbid with depression. Show less

The highly conserved long non-coding RNA (lncRNA) MIR505HG has been primarily recognized as a precursor for microRNAs (miR)-424 and miR-503. However, studies have since demonstrated that MIR503HG has distinct functions from its associated miRNAs, playing important roles in cell proliferation, invasion, apoptosis, and differentiation. While these miRNAs are known to influence cardiomyocyte differentiation, the specific role of MIR503HG in heart development remains unexplored. We seek to determine how MIR503HG deletion impacts ventricular chamber development and to identify underlying molecular mechanisms. To study the role of the lncRNA in vivo, we generated a functional MIR503HG knockout mouse model (MIR503HG-/-) using a synthetic polyadenylation signal to terminate MIR503HG transcription without affecting miR-424/503 expression. We performed morphological analyses on embryonic and adult hearts using microCT along with cardiac functional analysis via transthoracic echocardiography. We further apply single-nuclei RNA sequencing (snRNA-seq) on adult hearts to identify potential molecular mechanisms underlying the observed phenotypes. Functional deletion of MIR503HG alone was associated with reduced compact myocardium thickness and increased trabecular myocardium in the left ventricle (LV) at embryonic day 17.5 compared to wild-type mice, indicating a LV non-compaction (LVNC) phenotype. Moreover, adult MIR503HG-/- mutant hearts showed increased trabecular complexity, impaired LV relaxation, and mitral valve regurgitation. SnRNA-seq further revealed altered expression of several genes associated with cardiomyocyte function and LVNC, including Actc1, Mib1, Mybpc3, and Myh7. Lastly, Notch1 activity was also significantly increased in mutant hearts which has been previously associated with LVNC. MIR503HG plays a role in ventricular chamber development, and its deletion leads to an LVNC phenotype independent of the miRNA cluster within its locus, highlighting its importance in cardiac development and disease. We further suggest that abnormal Notch1 activity may underpin the LVNC phenotype presented. Show less

Epithelial to Mesenchymal transition (EMT) drives cancer metastasis and is governed by genetic and epigenetic alterations at multiple levels of regulation. It is well established that loss/mutation of p53 confers oncogenic function to cancer cells and promotes metastasis. Though transcription factors like ZEB1, SLUG, SNAIL and TWIST have been implied in EMT signalling, p53 mediated alterations in the epigenetic machinery accompanying EMT are not clearly understood. This work attempts to explore epigenetic signalling during EMT in colorectal cancer (CRC) cells with varying status of p53. Towards this, we have induced EMT using TGFβ on CRC cell lines with wild type, null and mutant p53 and have assayed epigenetic alterations after EMT induction. Transcriptomic profiling of the four CRC cell lines revealed that the loss of p53 confers more mesenchymal phenotype with EMT induction than its mutant counterparts. This was also accompanied by upregulation of epigenetic writer and eraser machinery suggesting an epigenetic signalling cascade triggered by TGFβ signalling in CRC. Significant agonist and antagonistic relationships observed between EMT factor SNAI1 and SNAI2 with epigenetic enzymes KDM6A/6B and the chromatin organiser SATB1 in p53 null CRC cells suggest a crosstalk between epigenetic and EMT factors. The observed epigenetic regulation of EMT factor SNAI1 correlates with poor clinical outcomes in 270 colorectal cancer patients taken from TCGA-COAD. This unique p53 dependent interplay between epigenetic enzymes and EMT factors in CRC cells may be exploited for development of synergistic therapies for CRC patients presenting to the clinic with loss of p53. Show less