Biology subjects

Joshi, C. G.

Publications and source records attributed to Joshi, C. G..

3 recordsLinked to original sources

bioRxiv2024

Ellagic acid: a potential inhibitor of enhancer of zeste homolog-2 and protein arginine methyltransferase-5

Dysregulation of epigenetic processes, characterized by aberrant DNA methylation patterns and histone modifications, is a hallmark of cancer, driving its initiation, progression, and metastasis by silencing tumor suppressor genes or activating oncogenes. Perturbations in histone modifications such as H3K27me3 by EZH2 and H4R3me2s by PRMT5 play significant roles in these epigenetic alterations, disrupting normal gene expression and facilitating oncogene activation while suppressing tumor suppressor genes. Consequently, inhibitors targeting enzymes involved in DNA methylation, histone modification, or chromatin remodeling, such as PRMTs and PRC complexes, are promising anti-cancer agents, with several undergoing pre-clinical and clinical trials. Our screening of a phytochemical library revealed ellagic acid as an effective inhibitor of both EZH2 and PRMT5. Ellagic acid interacts strongly with the EZH2 and PRMT5:MEP50 complex, binding to their active sites through {pi}-cation interactions and hydrogen bonds. Surface Plasmon Resonance study confirmed potent binding affinities of ellagic acid, with KD values of 3.28E-06 and 6.54E-05 for EZH2 and PRMT5:MEP50 respectively. In-vitro assays validated inhibitory effects on EZH2 and PRMT5:MEP50 by reducing the levels of their catalytic products H3K27me3 and H4R3me2s respectively and induction of autophagy and apoptosis. Further In-vivo studies using mouse xenografts further demonstrated significant tumor size reductions upon oral administration of ellagic acid, with decreased expression of the proliferative marker ki67 and histone repressive marks. Taken together we showed that inhibition of EZH2 and PRMT5:MEP50 by ellagic acid could be used to develop breast cancer therapeutic drug.

cancer biology↗

bioRxiv2024

Epigallocatechin-3-gallate inhibit the protein arginine methyltransferase 5 and Enhancer of Zeste homolog 2 in breast cancer both in vitro and in vivo

Histone methyltransferases are selectively catalyzing the methylation of lysine or arginine residues of target histone and non-histone proteins, classified as lysine methyltransferases and arginine methyltransferases. The EZH2 and PRMT5 catalyze trimethylation of H3 at K27 and symmetric dimethylation of H4 at R3 respectively. These histone repressive marks have been considered as hallmarks in cancer. Both PRMT5 and EZH2 over expressed in several cancers and have been considered as important target of drug development. As a result, many synthetic molecules as inhibitors of both PRMT5 and EZH2 are at different level of preclinical and clinical phases. Cancer atlas data analysis revealed that both PRMT5 and EZH2 had shown more than 90% amplification in breast cancer alone. We screened an array of phytocompounds towards the inhibition of PRMT5 and EZH2 using in silico, in vitro assays. Among them Epigallocatechin-3-gallate (EGCG) has interacted with human PRMT5: MEP50 and EZH2 efficiently. The EGCG interacted within the SAM binding site, with a {pi}-cation interaction at Lys 333 and H-bonds with Tyr324, Tyr334, Gly365, Leu437, and Glu444. Surface plasmon resonance analysis revealed that EGCG has strong binding affinity in nanomolar concentrations with both PRMT5-MEP50 than EZH2. Further in vitro methylation and cell-based assays proved the inhibitory potential of EGCG by reducing the catalytic products of PRMT5 and EZH2 i.e., H4R3me2s & H3K27me3 respectively and showed that it induced autophagy and apoptosis. Furthermore in vivo, mouse xenografts studies demonstrated that oral dosage, reduced tumor size significantly with reduction in proliferation marker Ki67 and these histone repressive marks. Finally conclude that inhibition of PRMT5 and EZH2 by EGCG potentially can be used to develop combined therapeutic approaches.

cancer biology↗

bioRxiv2018

High-throughput Genotype based Population Structure Analysis of Selected Buffalo Breeds

The water buffalo (Bubalus bubalis) has shown enormous milk production potential in many Asian countries. India is considered as the home tract of some of the best buffalo breeds. However, genetic structure of the Indian river buffalo is poorly understood. Hence, for selection and breeding strategies, there is a need to characterize the populations and understand the genetic structure of various buffalo breeds. In this study, we have analysed genetic variability and population structure of seven buffalo breeds from their respective geographical regions using Axiom(R) Buffalo Genotyping Array having 124,030 Single Nucleotide Polymorphisms (SNPs). Blood samples were obtained from 302 buffaloes comprising Murrah, Nili-Ravi, Mehsana, Jaffarabadi, Banni, Pandharpuri and Surti breeds. Diversity, as measured by expected heterozygosity (He) ranged from 0.364 in the Surti to 0.384 in the Murrah breed. All the breeds showed negligible inbreeding coefficient. Pair-wise FST values revealed the lowest genetic distance between Mehsana and Nili-Ravi (0.0022) while highest between Surti and Pandharpuri (0.030). Principal component analysis and structure analysis unveiled the differentiation of Surti, Pandharpuri and Jaffarabadi in first two PCs, while remaining breeds were grouped together as a separate single cluster. Murrah and Mehsana showed early linkage disequilibrium decay while Surti breed showed late decay, similarly LD based Ne was drastically declined for Murrah and Mehsana since last 100 generations. In LD blocks to QTLs concordance analysis, 14.19 per cent of concordance was observed with 873 (out of 1144) LD blocks overlapped with 8912 (out of 67804) QTLs. Overall, total 4090 markers were identified from all LD blocks for six types of traits. Results of this study indicated that these SNP markers could differentiate phenotypically distinct breeds like Surti,Pandharpuri and Jaffarabadi but not others. So, there is a need to develop SNP chip based on SNP markers identified by sequence information of local breeds.\n\nAuthor SummaryIndian buffaloes, through 13 recognised breeds, contribute about 49% in total milk production and play a vital role in enhancing the economic condition of Indian farmers. High density genotyping these breeds will allow us to study differences at the molecular level. Evolutionary relationship and phenotypes relations with genotype could be tested with high density genotyping. Breed structure analysis helps to take effective breeding policy decision. In the present study, we have used the high-throughput microarray based genotyping technology for SNP markers. These markers were used for breed differentiation using various genetic parameters. Population structure reflected the proportion of breed admixture among studied breeds. We have also tried to dig the markers associated with traits based LD calculation. However, these SNPs couldnt explain obvious variation up to the expected level, hence, there is need to develop an indigenous SNP chip based on Indian buffalo populations.

genomics↗