Biology subjects

Bhattacharjee, M.

Publications and source records attributed to Bhattacharjee, M..

6 recordsLinked to original sources

bioRxiv2025

O-GlcNAc Transferase Regulates GABAergic Synapse Organization and Receptor Composition.

Neural circuits must integrate metabolic information to maintain stable activity and appropriate behavioral responses. While metabolic regulation of excitatory synapses has been well studied, far less is known about how inhibitory synapses respond to changes in energy state. In this study, we show that O-GlcNAc transferase (OGT), a dynamic sensor of cellular nutrient flux, localizes to postsynaptic sites of the inhibitory synapses where it modulates synapse morphology and receptor composition. OGT over-expression reduced the size and intensity of vGAT and gephyrin puncta, whereas conditional OGT deletion produced a converse enlargement and redistribution of inhibitory scaffolds and vesicular proteins. Furthermore, OGT deletion accelerated inhibitory postsynaptic current decay kinetics and induced subunit-specific shifts in GABAA receptor surface expression: {beta}3 subunits decreased, whereas {gamma}2 subunit total and surface levels increased. Together, these findings identify OGT as a metabolic regulator that modulates inhibitory synapse structure and signaling, providing a mechanistic link between energy state and GABAergic circuit function in health and disease.

neuroscience↗

bioRxiv2025

Satiation is associated with OGT-dependent regulation of excitatory synapses.

Satiation is essential for energy homeostasis and is dysregulated in metabolic disorders like obesity and eating disorders such as anorexia nervosa. While satiation engages a large neural network across brain regions, how the communication within this network depends on metabolic fluctuations is unclear. This study shows that nutrient access can affect neuron-to-neuron communication in this network by regulating excitatory synaptic plasticity through O-GlcNAc transferase (OGT) in CaMKII satiation neurons in the paraventricular nucleus (PVN). Using cell-specific knockout mice and electrophysiological recordings, we demonstrate that OGT deletion in PVNCaMKII neurons increases input resistance and neuronal excitability while preserving basic membrane electrical properties. Strikingly, feeding triggered a robust 3.8-fold increase in the excitatory synaptic input in wild-type neurons, whereas OGT-knockout neurons failed to exhibit this feeding-induced synaptic activation, instead displayed a paradoxical trend towards increases in synaptic activity during hungry conditions. Furthermore, OGT deletion destabilized glucose-dependent synaptic responses, with knockout neurons displaying maladaptive depression of excitatory transmission in conditions where stability is normally preserved. These findings establish OGT as a nutrient-sensitive modulator of synaptic plasticity that ensures appropriate satiation signalling by coupling metabolic state to synaptic plasticity.

neuroscience↗

bioRxiv2023

Molecular pathways and cellular subsets associated with adverse clinical outcomes in overlapping immune-related myocarditis and myositis

Immune checkpoint therapies (ICTs) can induce life-threatening immune-related adverse events, including myocarditis and myositis, which are rare but often concurrent. The molecular pathways and immune subsets underlying these toxicities remain poorly understood. To address this need, we obtained heart and skeletal muscle biopsies for single-cell RNA sequencing in living patients with cancers treated with ICTs admitted to the hospital with myocarditis and /or myositis (overlapping myocarditis plus myositis, n=10; myocarditis-only, n=1) compared to ICT-exposed patients ruled out for toxicity utilized as controls (n=9) within 96 hours of clinical presentation. Analyses of 58,523 cells revealed clonally expanded CD8+ T cells with a cytotoxic phenotype expressing activation/exhaustion markers in both myocarditis and myositis. Furthermore, the analyses identified a population of tissue-resident myeloid cells expressed Fc{gamma}RIIIa, which is known to bind IgG and regulate complement activation. Immunohistochemistry of affected cardiac and skeletal muscle tissues revealed protein expression of pan-IgG and complement product C4d that were associated with the presence of high-titer serum autoantibodies against muscle antigens in a subset of patients. We further identified a population of inflammatory IL-1B+TNF+ myeloid cells specifically enriched in myocarditis and associated with greater toxicity severity and poorer clinical outcomes. These results are the first to recognize these myeloid subsets in human immune-related myocarditis and myositis tissues and nominate new targets for investigation into rational treatments to overcome these high-mortality toxicities. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/556590v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@b5895forg.highwire.dtl.DTLVardef@4dec8corg.highwire.dtl.DTLVardef@1e50cb9org.highwire.dtl.DTLVardef@a653fd_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Overexpression of Interleukin-8 and Interleukin-13 as potent immune markers associated with survival and dietary habits in esophageal squamous cell carcinoma.

BackgroundInterleukin-8 (IL8), Interleukin-12 (IL12) and Interleukin-13 (IL13) are cytokines that play regulatory role in cancer pathogenesis. We analysed their expression profile to evaluate as molecular biomarkers of esophageal squamous cell carcinoma (ESCC) and their association with different parameters. MethodsExpression analysis of IL8, IL12 and IL13 were performed by Real time qPCR in blood and tumor tissue of 120 ESCC patients. The expression profiles were associated with different clinicopathological and dietary factors. Survival and hazard analysis were also performed. ResultsWhen compared to normal controls, IL8 expression showed upregulation in 83% tissue samples (p=0.000) and 62% blood samples (p=0.388), IL12 expression showed upregulation in 62% tissue samples (p=0.435) and 57% blood samples (p=0.222) and IL13 expression showed upregulation in 83% tissue samples (p=0.001) and 68% blood samples (p=0.312). Significant positive correlation (p<0.05) was observed between tissue and blood level expression of IL8, IL12 and IL13. Different clinicopathological factors and dietary habits showed significant association (p<0.05) with IL8, IL12 and IL13 expression.. Statistically significant positive correlation were observed for IL8 and IL13 expression in tissue as well as IL13 and IL12 expression in both tissue and blood. Also significant negative correlation of IL8 and IL12 expression in blood and tissue were also observed. Tumor stage, node stage, metastasis, consumption of betel nut, tobacco, alcohol, hot food, smoked food, spices, IL8 expression in blood, IL13 expression in tissue and IL12 expression in blood and tissue showed significant association (p<0.05) with survival of ESCC patients. ConclusionsAltered expression of IL8, IL12 and IL13 may be associated with ESCC progression. Overexpression of IL8 and IL13 in tissue samples may be potential biomarkers for ECSS screening. Additionally, results from both survival and hazard analysis data indicate the effects of various parameters on the survival and mortality rate of ESCC patients.

immunology↗

bioRxiv2022

A mechanistic insight into Nigella sativa mediated anticancer effect on breast cancer through regulation of various miRNAs: An in vitro & in vivo study

BackgroundCancer continues to threat the mortal alongside scientific community with its burgeoning grasp. Although efforts have been directed to tame cancer by radiotherapy, photodynamic therapy, chemotherapy it came at a cost of fatal side effects. PurposePlant derived bioactive compounds carries an inevitable advantage of being safer, bioavailable & less toxic compared to contemporary chemotherapeutics. This study analyzed anti-cancerous potential of volatile oil, extracted from Nigella sativa, in-vitro against MDA-MB-231, MCF-7 & in-vivo on tumor growth in mice after successful oral administration. Study DesignOur strategic approach employed solvent extraction of black seed oil (BSO) to highlight orchestrated use of its potent integrants - TQ, Carvacrol & TA which in modest amounts show anti-cancerous properties compared to their individual treatment. We attempted to show this cost effective, safe & bioavailable form of dealing with the atrocities of breast cancer by means of MTT, Apoptotic, Western Blot Assays besides Transwell & Wound healing Assay. Reduction in the solid tumour in-vivo & near normalcy restoration of tissue section architecture from the BSO treated tumour sets are indicative of the better anti-tumorigenic potential of BSO. MethodsBSOs Solvent extraction was performed followed by its characterization. MTT aided cytotoxicity study of BSO alongside major components in PBMC & cancer cells while its efficacy was presented by flow cytometric ROS analysis, cell cycle arrest & apoptosis assessment. Anti-migratory potential evaluated by Wound Healing, Transwell Migration & Western Blot while the expression study of a wide range of proteins, miRNAs & the in-vivo studies undertaken climaxed the confirmation of the anti-cancerous potential of BSO. ResultsComparatively reduced concentrations of TQ, TA & Carvacrol in BSO played a synergistic role to enhance apoptotic potential via Caspase 7 & 9, through enhanced ROS & expression of apoptotic family of proteins, miRNAs besides uplifting the anti-migratory perspective by effectively enhancing E-cad & downregulating lamellipodia, filopodia assembly & MMPs in MCF-7 & MDA-MB-231. Similar observations in-vivo outlined the therapeutic potential of BSO. ConclusionThis study culminates isolation & processing of BSO in a simplified procedure, thereby aiming at a more lucrative paradigm to be accepted in contemporary phytomedicine research.

cancer biology↗

bioRxiv2020

Characterization of Plasmodium falciparum NEDD8 and identification of cullins as its substrates

A variety of post-translational modifications of Plasmodium falciparum proteins, including phosphorylation and ubiquitination, are shown to have key regulatory roles. The neural precursor cell expressed developmentally downregulated protein 8 (NEDD8) is a ubiquitin-like modifier of cullin-RING E3 ubiquitin ligases, which regulate diverse cellular processes, including the cell-cycle. Although neddylation pathway is conserved in eukaryotes, it is yet to be characterized in Plasmodium and related apicomplexan parasites. Towards studying the neddylation pathway in malaria parasites, we characterized P. falciparum NEDD8 (PfNEDD8) and identified cullins as its physiological substrates. PfNEDD8 is a 76 amino acid residue protein without the C-terminal tail, indicating that it can be readily conjugated. The wild type and mutant (Gly75Gly76 mutated to Ala75Ala76) PfNEDD8 were expressed in P. falciparum. Western blot of wild type PfNEDD8-expressing parasites indicated multiple high molecular weight conjugates, which were absent in the parasites expressing the mutant, indicating conjugation of NEDD8 to proteins through Gly76. Immunoprecipitation followed by mass spectrometry of wild type PfNEDD8-expressing parasites identified several proteins, including two putative cullins. Furthermore, we expressed PfNEDD8 in mutant S. cerevisiae strains that lacked endogenous NEDD8 ({Delta}rub1) or NEDD8 conjugating E2 enzyme ({Delta}Ubc12). The western blot of complemented strains and mass spectrometry of PfNEDD8 immunoprecipitate showed conjugation of PfNEDD8 to S. cerevisiae cullin cdc53, demonstrating functional conservation and cullins as the physiological substrates of PfNEDD8. The characterization of PfNEDD8 and identification of cullins as its substrates make ground for investigation of specific roles and drug target potential of neddylation pathway in malaria parasites.

biochemistry↗