Biology subjects

Purandare, N.

Publications and source records attributed to Purandare, N..

3 recordsLinked to original sources

bioRxiv2024

Impact of genomic background and developmental state on signaling pathways and response to therapy in Glioblastoma patient-derived cells

Glioblastoma (GBM) tumors represents diverse genomic epigenomic, and transcriptional landscapes, with significant intratumoral heterogeneity that challenges standard of care treatments involving radiation (RT) and the DNA-alkylating agent temozolomide (TMZ). In this study, we employed targeted proteomics to assess the response of a genomically-diverse panel of GBM patient-derived cancer stem cells (CSCs) to astrocytic differentiation, growth factor withdrawal and traditional high fetal bovine serum culture. Our findings revealed a complex crosstalk and co-activation of key oncogenic signaling in CSCs and diverse patterns of response to these external stimuli. Using RNA sequencing and DNA methylation, we observed common adaptations in response to astrocytic differentiation of CSCs across genomically distinct models, including BMP-Smad pathway activation, reduced cholesterol biosynthesis, and upregulation of extracellular matrix components. Notably, we observed that these differentiated CSC progenies retained a subset of stemness genes and the activation of cell survival pathways. We also examined the impact of differentiation state and genomic background on GBM cell sensitivity and transcriptional response to TMZ and RT. Differentiation of CSCs increased resistance to TMZ but not to RT. While transcriptional responses to these treatments were predominantly regulated by p53 in wild-type p53 GBM cells, its transcriptional activity was modulated by the differentiation status and treatment modality. Both mutant and wild-type p53 models exhibited significant activation of a DNA-damage associated interferon response in CSCs and differentiated cells, suggesting this pathway may play a wider role in GBM response to TMZ and RT. Our integrative analysis of the impact of GBM cell developmental states, in the context of genomic and molecular diversity of patient-derived models, provides valuable insights for pre-clinical studies aimed at optimizing treatment strategies.

cancer biology↗

bioRxiv2023

MNRR1 activation by nitazoxanide abrogates lipopolysaccharide- induced preterm birth in mice

Intra-amniotic inflammation leading to preterm birth is one of the leading causes of neonatal morbidity and mortality. We recently found that the mitochondrial levels of MNRR1 (Mitochondrial Nuclear Retrograde, Regulator 1; also called CHCHD2, AAG10, or PARK22), an important bi-organellar regulator of cellular function, are reduced in the context of inflammation and that both genetic and pharmacological increase in MNRR1 levels can counter the inflammatory profile. We show here that nitazoxanide, a clinically-approved drug, is an activator of MNRR1 and prevents preterm birth in a well-characterized murine model caused by intra-amniotic lipopolysaccharide (LPS) injection. HighlightsO_LINitazoxanide exerts anti-inflammatory functions via activation of MNRR1. C_LIO_LIOral administration of nitazoxanide prevents preterm birth in mouse model of intra-intraamniotic LPS-induced inflammation. C_LI

immunology↗

bioRxiv2021

Lipopolysaccharide induces placental mitochondrial dysfunction by reducing MNRR1 levels via a TLR4-independent pathway

Mitochondria play a key role in the growth and development of the placenta, an organ essential for pregnancy in eutherian mammals. Mitochondrial dysfunction has been associated with pregnancy pathologies. However, the mechanisms whereby placental mitochondria sense inflammatory signals at a cellular and mechanistic level are unknown. Mitochondrial Nuclear Retrograde Regulator 1 (MNRR1) is a bi-organellar protein responsible for optimal mitochondrial function to achieve energy and redox homeostasis. In addition, MNRR1 also is required for optimal induction of cellular stress-responsive signaling pathways such as the mitochondrial unfolded protein response (UPRmt). Here, in a lipopolysaccharide-induced model of placental inflammation, we show that MNRR1 levels are reduced in placental tissues and cell lines. Reduction in MNRR1 is associated with mitochondrial dysfunction and enhanced oxidative stress along with activation of pro-inflammatory signaling. Mechanistically, we uncover a non-conventional pathway independent of Toll-like receptor 4 (TLR4) that results in a specific ATM kinase-dependent threonine phosphorylation and activation of a mitochondrial protease, YME1L1, degrading MNRR1. Furthermore, enhancing MNRR1 levels in placental cells either genetically or with specific activators abrogates the bioenergetic defect and induces an anti-inflammatory phenotype, suggesting that MNRR1 is upstream of the mitochondrial dysfunction observed in our model. Reduction in MNRR1 levels is a generalized phenomenon observed in cells under an inflammatory stimulus. We therefore propose MNRR1 as a novel anti-inflammatory therapeutic target in pathologies associated with placental inflammation.

molecular biology↗