Biology subjects

Majumdar, S. S.

Publications and source records attributed to Majumdar, S. S..

9 recordsLinked to original sources

bioRxiv2025

Early detection of oxidative stress in mammary epithelial cells by using secreted Cyclophilin A as a marker in the milk.

ObjectiveTo investigate the secretion and expression of cyclophilin A (CypA) in mammary epithelial cells in vitro under oxidative stress conditions and to evaluate its potential as a biomarker of oxidative stress in dairy cows. MethodsPrimary mammary epithelial cells isolated from goat mammary gland, luminal epithelial cells isolated from goat milk and mouse mammary epithelial cells were cultured and treated with hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BHP) to induce oxidative stress. Cell viability, intracellular reactive oxygen species (ROS) levels, lipid peroxidation, and antioxidant enzyme activity were measured to assess the oxidative status of cells. CypA gene expression was quantified using quantitative reverse transcription polymerase chain reaction and the secreted CypA levels were measured by using enzyme linked immunosorbent assay and immunoblotting. Milk samples from various cow breeds were also analysed for somatic cell count, catalase activity and CypA levels. ResultsThe primary mammary epithelial cells culture displayed typical epithelial cell morphology. Oxidative stress induced by 200 {micro}M of both H2O2 and t-BHP and an exposure duration of 1 hour was observed to be optimum in inducing oxidative stress. A significant increase in ROS levels and lipid peroxidation index was observed across all cell types. Catalase activity was also elevated in the treated cells. An upregulation of CypA gene expression was observed in response to oxidative stress with a significant increase in CypA protein levels. Milk samples from the various cattle breeds revealed varying somatic cell counts with the highest in Kankrej and lowest in Holstein Friesian. ConclusionThese findings demonstrate that CypA is secreted from the mammary epithelial cells in response to oxidative stress and may serve as a potential biomarker for oxidative stress in dairy cows.

cell biology↗

bioRxiv2025

Multi-omics analysis uncovers differential growth kinetics of Japanese Encephalitis Virus in human and porcine macrophages

Japanese encephalitis virus (JEV), a mosquito-borne neurotropic virus, poses a significant threat to juvenile humans, while causing mild symptoms in pigs, except piglets. Pigs with high viremia are amplifier hosts, whereas humans with lower viremia are dead-end hosts. The molecular mechanisms behind the varying viremia levels in pigs and humans remain poorly understood. A comparative multi-omics study was conducted on JEV-infected macrophages, the early site of JEV replication in both species. We identified 24 key determinants potentially regulating viral growth. Functional validation of three antiviral factors - LGALS1, ssc-miR-133a-3p, and hsa-miR-3614-5p, and two proviral factors - MIF and VMP1, in macrophages showed that the upregulation of MIF and VMP1, and downregulation of ssc-miR-133a-3p, enhanced JEV replication in pigs. In contrast, the downregulation of MIF and VMP1 and upregulation of hsa-miR-3614-5p reduced JEV replication in human macrophages. These findings provide critical insights into JEV infection and its species-specific dynamics.

microbiology↗

bioRxiv2025

NOR1 and Mitophagy: An Insight into Sertoli Cell Function Regulating Spermatogenesis

The development and differentiation of germ cell (Gc) is supported by the Sertoli cel (Sc). We previously reported that a developmental switch in Sc around 12 days of age onwards in rats. During the process of differentiation of Sc, the differential expression of mitophagy-related genes and its role in male fertility is poorly understood. To address this gap, we evaluated the microarray dataset GSE48795 to identify 12 mitophagy-related hub genes - Egfr, Bcl2, Ccl2, Mmp2, Igf1, Fgf7, Apoe, Fos, Cxcl12, Ocln, Dcn, and Snca. We identify NOR1 as a potential mitophagy-related gene of interest due to its strong regulatory association with two hub genes Bcl2 and Fos. To determine the importance of our analysis of finding key mitophagy-related genes, we generated a transgenic rat model with Sc-specific knockdown of NOR1 during puberty. Adult male transgenic rats were found to be infertile due to impaired spermatogenesis, indicating a critical role for NOR1 in Sc function. These findings suggest that mitophagy-related genes may play an important role in the differentiation of Sc and thereby, regulate male fertility.

cell biology↗

bioRxiv2025

Genome assemblies of Indian desi cattle reveals hotspots of rearrangements and immune-related genetic diversity

India, home to the worlds largest cattle population, hosts native dairy breeds essential to its agricultural economy because of their adaptability and resilience. This study characterizes the genomes of five prominent breeds Gir, Kankrej, Red Sindhi, Sahiwal and Tharparkar, highlighting their unique genomic characteristics. The de novo assemblies ranged from 2.70-2.78 Gb in size, with 90% of the genomes assembled in just 56 to 1,663 scaffolds. The use of reference-guided scaffolding further enhanced these genomes, resulting in 93.3-96.7% pseudomolecule coverage with strong BUSCO scores (94.1-95.5%). Comparative analyses revealed 87-95% synteny with the Brahman genome and identified 19.84-153.16 Mb of structural rearrangements per genome, including inversions, translocations, and duplications. Synteny diversity analysis uncovered 10,643 perfectly collinear regions spanning 87.3 Mb and 6,622 hotspots of rearrangement (HOT regions) covering 55.18 Mb. These HOT regions, characterized by high synteny diversity, were significantly enriched with immune-related genes. Moreover, immune-related gene clusters, including MHC, NKC, and LRC, were identified within HOT regions in the desi reference genome. Our findings provide valuable insights into the genetic diversity of desi cattle breeds. The high-quality genome assemblies generated in this study will serve as valuable resources for future research in genetic improvement, disease resistance, and environmental adaptation.

genomics↗

bioRxiv2024

Generation of a Transgenic Mouse Model for Investigating Mitochondria in Sperm

Mitochondria play a crucial role in the sperm development; however, the mechanisms regulating their function in sperm remain poorly understood. Developing a method to regulate the expression of a target gene within the mitochondria of sperm is a vital step in this area of research. In this study, we aimed to create a system for expressing a transgene in the mitochondria of sperm. As a proof of concept, we generated transgenic mice that express green fluorescent protein (GFP) fused with a mitochondrial localization signal (MLS) driven by the phosphoglycerate kinase 2 (PGK2) promoter, which facilitates the transgene expression in the sperm. Although the PGK2 promoter has previously shown to drive gene expression in spermatocytes and spermatids, the novelty of our approach lies in the combination of PGK2-driven MLS-GFP expression to study mitochondria in vivo. We established two founder lines of transgenic mice through pronuclear microinjection, and MLS-GFP expression was confirmed in the mitochondria of sperm cells using fluorescence microscopy and flow cytometry. Consequently, we provide a novel platform for investigating mitochondrial function in sperm, where GFP can be substituted with other genes of interest to examine their effects on mitochondria. This system specifically targets sperm mitochondria, offering an innovative approach for studying mitochondrial function in vivo.

cell biology↗

bioRxiv2024

Constructing a Draft Indian Cattle Pangenome Using Short-Read Sequencing

BackgroundIndian cattle known as desi cattle, renowned for their adaptability to harsh environments and diverse phenotypic traits, represent a valuable genetic resource. While reference genome assemblies have been instrumental in advancing cattle genomics, they often fail to capture the full spectrum of genetic variation present within diverse populations. To address this limitation, we aimed to construct a pangenome for desi cattle by identifying and characterizing Non-Reference Novel Sequences (NRNS). FindingsWe sequenced 68 desi cattle genomes representing seven distinct breeds, generating 48.35 billion short reads. A PanGenome Analysis (PanGA) pipeline was developed in Bash scripts to process these data to identify NRNS missing in the reference genome. A total of 13,065 NRNS with a cumulative length of [~]41 Mbp were identified that exhibited substantial variation across the population. These NRNS were found to be exclusive to Indian desi cattle, matching only 4.1% with the Chinese indicine pangenome. However, a significant proportion ([~]40%) of NRNS displayed ancestral origins within the Bos genus. These sequences were enriched in genic regions, suggesting functional roles, and were associated with quantitative trait loci (QTLs), particularly for milk production. Compared to a single reference genome, the pangenome approach significantly enhanced read mapping accuracy, reduced spurious SNP calls, and facilitated the discovery of novel genetic variants. ConclusionsThis study has successfully established a within-species cattle pangenome specifically focused on desi cattle breeds from India. Our findings highlight the importance of pangenome based analyses for understanding the complex genetic architecture of desi cattle.

genomics↗

bioRxiv2024

Advancing the Indian Cattle Pangenome: Characterizing Non-Reference Sequences in Bos indicus

BackgroundIndia, with the worlds largest cattle population and more than 50 registered breeds of Bos indicus, stands as a vital reservoir of genetic diversity. However, the abundant diversity among Indian cattle breeds highlights the inadequacy of a single reference sequence to represent the entire genomic content of desi cattle. We recognize the need to capture the genomic differences within the Bos indicus population as a whole, and specifically within the dairy cattle subset by identifying non-reference sequences and constructing a pangenome. FindingFive representative genomes of prominent dairy breeds, including Gir, Kankrej, Tharparkar, Sahiwal, and Red Sindhi, were sequenced using 10X Genomics Linked-Read technology. Assemblies generated from these linked-reads ranged from 2.70 Gb to 2.77 Gb,comparable to the Bos indicus Brahman reference genome. A pangenome of Bos indicus cattle was constructed by comparing the newly assembled genomes with the reference using alignment and graph-based methods, revealing 8 Mb and 17.7 Mb of novel sequence respectively. A confident set of 6,844 Non-Reference Unique Insertions (NUIs) spanning 7.57 Mbs was identified through both methods, representing the pangenome of Indian Bos indicus breeds. Comparative analysis with previously published pangenomes unveiled 2.8 Mb (37%) commonality with the Chinese indicine pangenome and only 1% commonality with the Bos taurus pangenome. Among these, 2,312 NUIs - encompassing [~]2 Mb, were commonly found in 98 samples of the 5 breeds and designated as Bos indicus Common Insertions (BICIs) in the population. Furthermore, 926 BICIs were identified within 682 protein-coding genes, 54 long non-coding RNAs (LncRNA), and 18 pseudogenes. These protein-coding genes were enriched for functions such as chemical synaptic transmission, cell junction organization, cell-cell adhesion, and cell morphogenesis. The protein-coding genes were found in various prominent Quantitative Trait Loci (QTL) regions, suggesting potential roles of BICIs in traits related to milk production, reproduction, exterior, health, meat, and carcass. Notably, 63.21% of the bases within the BICIs call set contained interspersed repeats, predominantly LINEs. Additionally,70.28% of BICIs are shared with other domesticated and wild species, highlighting their evolutionary significance. ConclusionThis is the first report unveiling a robust set of NUIs defining the pangenome of Bos indicus breeds of India. The analyses contribute valuable insights into the genomic landscape of desi cattle breeds.

genomics↗

bioRxiv2022

PD-L1 activity is associated with partial EMT and metabolic reprogramming in carcinomas

Immune evasion and metabolic reprogramming are hallmarks of cancer progression often associated with a poor prognosis and frequently present significant challenge for cancer therapies. Recent studies have emphasized on the dynamic interaction between immunosuppression and the dysregulation of energy metabolism in modulating the tumor microenvironment to promote cancer aggressiveness. However, a pan-cancer association among these two hallmarks, and a potent common driver for them - Epithelial-Mesenchymal Transition (EMT) - remains to be done. Here, our meta-analysis across 184 publicly available transcriptomic datasets as well as The Cancer Genome Atlas (TCGA) data reveals that an enhanced PD-L1 activity signature along with other immune checkpoint markers correlate positively with a partial EMT and elevated glycolysis signature but a reduced OXPHOS signature in many carcinomas. These trends were also recapitulated in single-cell RNA-seq time-course EMT induction data across cell lines. Furthermore, across multiple cancer types, concurrent enrichment of glycolysis and PD-L1 results in worse outcomes in terms of overall survival as compared to enrichment for only PD-L1 activity or expression. Our results highlight potential functional synergy among these interconnected axes of cellular plasticity in enabling metastasis and/or multi-drug resistance in cancer.

cancer biology↗

bioRxiv2021

Quantifying the patterns of metabolic plasticity and heterogeneity along the epithelial-hybrid-mesenchymal spectrum in cancer

Cancer metastasis is the leading cause of cancer-related mortality and the process of Epithelial to Mesenchymal Transition (EMT) is crucial for cancer metastasis. Either a partial or complete EMT have been reported to influence the metabolic plasticity of cancer cells in terms of switching among oxidative phosphorylation, fatty acid oxidation and glycolysis pathways. However, a comprehensive analysis of these major metabolic pathways their associations with EMT across different cancers is lacking. Here, we analyse more than 180 cancer cell datasets and show diverse associations of these metabolic pathways with the EMT status of cancer cells. Our bulk data analysis shows that EMT generally positively correlates with glycolysis but negatively with oxidative phosphorylation and fatty acid metabolism. These correlations are also consistent at the level of their molecular master regulators, namely AMPK and HIF1. Yet, these associations are shown to not be universal. Analysis of singlecell data of EMT induction shows dynamic changes along the different axes of metabolic pathways, consistent with general trends seen in bulk samples. Together, our results reveal underlying patterns of metabolic plasticity and heterogeneity as cancer cells traverse through the epithelial-hybrid-mesenchymal spectrum of states.

cancer biology↗