Biology subjects

Mehra, V.

Publications and source records attributed to Mehra, V..

5 recordsLinked to original sources

bioRxiv2025

Modulating p38MAPK recalibrates sensitivity of drug-resistant pancreatic adenoductal carcinoma cells toward chemotherapy and correlate with improved outcome in PDAC patients: Experimental and metadata evidence

Pancreatic cancer is one of the deadliest cancers and has very limited therapeutic options and a dismal prognosis. Among various signaling pathways which are activated during tumor development, hyperactivation of Mitogen-Activated Protein Kinase (MAPK) is responsible for high grade angiogenesis, polarization of Tumor Associated Macrophages, unfolded protein responses and exhaustion of T cells, which together contributes towards this therapeutic resistance. We therefore believe that MAPK targeting is expected to enhance sensitivity of highly resistant PDAC cells toward various cancer directed interventions. In this context, we investigated the impact of modulating p38MAPK on the sensitivity of pancreatic cancer cells towards gemcitabine. Supporting our hypothesis, our results convincely, demonstrated that indeed, p38 inhibition sensitizes both KRAS positive Panc-1 and MiaPaCa2 pancreatic carcinoma cells towards gemcitabine induced death. Interestingly p38MAPK targeting significantly reduced the cell viability, clonogenic potential of these cells and enhanced the early apoptosis. Our in-silico studies, supporting our in vitro data, potentially correlated that that high expression of p38 MAPK14 in PDAC patients is associated with poor prognosis and disease free survival. Deep miming of in silico data further demonstrated that MAPK14, in association with, hypoxia inducible factor-1 alpha and vascular endothelial growth factor signaling pathways promote angiogenic programming of PDAC which render these tumors refractory for cancer directed interventions. Based on our preliminary data, we believe that p38 MAPK based approach is potential approach for changing the faith of PDAC patients toward chemo and immunotherapy and believed to improve PDAC burden effectively in the host. HighlightsO_LIp38 MAPK inhibition enhances the sensitivity of KRAS+ pancreatic cancer cells for Gemcitabine C_LIO_LIP38MAPK knockdown cells are sensitive for Gemcitabine induced death C_LIO_LIMAPK14 (p38) is associated with angiogenesis and poor prognosis in pancreatic cancer C_LIO_LIMAPK14 Regulates Pro-Tumorigenic Pathways and immune infiltration in Pancreatic Cancer C_LI

cancer biology↗

bioRxiv2021

Brain-wide quantification of the supraspinal connectome

The supraspinal connectome is essential for normal behavior and homeostasis and consists of numerous sensory, motor, and autonomic projections from brain to spinal cord. Study of supraspinal control and its restoration after damage has focused mostly on a handful of major populations that carry motor commands, with only limited consideration of dozens more that provide autonomic or crucial motor modulation. We now provide an experimental platform and associated web-based resource to rapidly profile the entire supraspinal mesoconnectome in adult mice. Optimized viral labeling, 3D imaging, and registration to a mouse digital neuroanatomical atlas assigned tens of thousands of supraspinal neurons to more than 60 identified regions. We demonstrate the approachs ability to clarify essential points of topographic mapping between spinal levels, to measure population-specific sensitivity to spinal injury, and to resolve previously unexplained variability in functional recovery. This work will spur progress by broadening understanding and enabling analyses of essential but understudied supraspinal populations.

neuroscience↗

bioRxiv2020

Computational approaches identify novel transcription factor combinations that promote corticospinal axon growth following injury

Transcription factors (TFs) act as powerful levers to regulate neural physiology and can be targeted to improve cellular responses to injury or disease. Because TFs often depend on cooperative activity, a major challenge is to identify and deploy optimal sets. Here we developed a novel bioinformatics pipeline, centered on TF co-occupancy of regulatory DNA, and used it to predict factors that potentiate the effects of pro-regenerative Klf6. High content screens of neurite outgrowth identified cooperative activity by 12 candidates, and systematic testing in an animal model of corticospinal tract (CST) damage substantiated three novel instances of pairwise cooperation. Combined Klf6 and Nr5a2 drove the strongest growth, and transcriptional profiling of CST neurons identified Klf6/Nr5a2-responsive gene networks involved in macromolecule biosynthesis and DNA repair. These data identify novel TF combinations that promote enhanced CST growth, clarify the transcriptional correlates, and provide a bioinformatics roadmap to detect TF synergy.

neuroscience↗

bioRxiv2018

Developmental chromatin restriction of pro-growth gene networks acts as an epigenetic barrier to axon regeneration in cortical neurons

Axon regeneration in the central nervous system is prevented in part by a developmental decline in the intrinsic regenerative ability of maturing neurons. This loss of axon growth ability likely reflects widespread changes in gene expression, but the mechanisms that drive this shift remain unclear. Chromatin accessibility has emerged as a key regulatory mechanism in other cellular contexts, raising the possibility that chromatin structure may contribute to the age-dependent loss of regenerative potential. Here we establish an integrated bioinformatic pipeline that combines analysis of developmentally dynamic gene networks with transcription factor regulation and genome-wide maps of chromatin accessibility. When applied to the developing cortex, this pipeline detected overall closure of chromatin in sub-networks of genes associated with axon growth. We next analyzed mature CNS neurons that were supplied with various pro-regenerative transcription factors. Unlike prior results with SOX11 and KLF7, here we found that neither JUN nor an activated form of STAT3 promoted substantial corticospinal tract regeneration. Correspondingly, chromatin accessibility in JUN or STAT3 target genes was substantially lower than in predicted targets of SOX11 and KLF7. Finally, we used the pipeline to predict pioneer factors that could potentially relieve chromatin constraints at growth-associated loci. Overall this integrated analysis substantiates the hypothesis that dynamic chromatin accessibility contributes to the developmental decline in axon growth ability and influences the efficacy of pro-regenerative interventions in the adult, while also pointing toward selected pioneer factors as high-priority candidates for future combinatorial experiments.

neuroscience↗

bioRxiv2018

KLF6 activates complementary gene modules relevant to axon growth and promotes corticospinal tract regeneration after spinal injury

Members of the KLF family of transcription factors can exert both positive and negative effects on axon regeneration in the central nervous system, but the underlying mechanisms are unclear. KLF6 and -7 share nearly identical DNA binding domains and stand out as the only known growth-promoting family members. Here we confirm that similar to KLF7, expression of KLF6 declines during postnatal cortical development and that forced re-expression of KLF6 in corticospinal tract neurons of adult female mice enhances axon regeneration after cervical spinal injury. Unlike KLF7, however, these effects were achieved with wildtype KLF6, as opposed constitutively active mutants, thus simplifying the interpretation of mechanistic studies. To clarify the molecular basis of growth promotion, RNA sequencing identified 454 genes whose expression changed upon forced KLF6 expression in cortical neurons. Network analysis of these genes revealed sub-networks of downregulated genes that were highly enriched for synaptic functions, and sub-networks of upregulated genes with functions relevant to axon extension including cytoskeleton remodeling, lipid synthesis and transport, and bioenergetics. The promoter regions of KLF6-sensitive genes showed enrichment for the binding sequence of STAT3, a previously identified regeneration-associated gene. Notably, co-expression of constitutively active STAT3 along with KLF6 in cortical neurons produced synergistic increases in neurite length. Finally, genome-wide ATAC-seq footprinting detected frequent co-binding by the two factors in pro-growth gene networks, indicating co-occupancy as an underlying mechanism for the observed synergy. These findings advance understanding of KLF-stimulated axon growth and indicate functional synergy of KLF6 transcriptional effects with those of STAT3.\n\nSIGNIFICANCE STATEMENTThe failure of axon regeneration in the CNS limits recovery from damage and disease. These findings show the transcription factor KLF6 to be a potent promoter of axon growth after spinal injury, and more importantly clarify the underlying transcriptional changes. In addition, bioinformatics analysis predicted a functional interaction between KLF6 and a second transcription factor, STAT3, and genome-wide footprinting confirmed frequent co-occupancy. Co-expression of the two factors yielded synergistic elevation of neurite growth in primary neurons. These data point the way toward novel transcriptional interventions to promote CNS regeneration.

neuroscience↗