Publications by authors named "Cheemala Ashok"

Loss of nuclear TDP-43 occurs in a wide range of neurodegenerative diseases, and specific mutations in the gene that encodes the protein are linked to familial Frontal Temporal Lobar Dementia (FTD), and Amyotrophic Lateral Sclerosis (ALS). Although the focus has been on neuronal cell dysfunction caused by TDP-43 variants, mRNA transcripts are expressed at similar levels in brain endothelial cells (ECs). Since increased permeability across the blood brain barrier (BBB) precedes cognitive decline, we postulated that altered functions of TDP-43 in ECs contributes to BBB dysfunction in neurodegenerative disease.

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Article Synopsis
  • The study highlights the challenges of studying endothelial cells (ECs) in the context of aging and neurodegenerative diseases, particularly due to difficulties in extracting their nuclei for analysis.
  • Researchers employed a novel technique called inCITE-seq to analyze nuclear proteins and RNA in ECs from human brain tissues, revealing a unique transcriptional signature linked to neurodegenerative diseases like ALS, FTD, and Alzheimer's.
  • The results indicate a loss of nuclear TDP-43 in disease-associated ECs, which affects the transcriptional regulation of inflammatory responses and could contribute to the deterioration of the blood-brain barrier in these neurodegenerative conditions.
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The Polycomb Repressive Complex (PRC) proteins, EZH2 and EZH1 regulate many biological processes by generating the repressive H3K27me3 modifications in the chromatin. However, the factors that regulate the EZH1/EZH2 functions are poorly studied. We identify that the 3'UTRs of EZH2 and EZH1 mRNAs contain the binding sites for the miRNA, miR-150.

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Epithelial splicing regulatory protein 1 (ESRP1) is an RNA binding protein that governs the alternative splicing events related to epithelial phenotypes. ESRP1 contributes significantly at different stages of cancer progression. ESRP1 expression is substantially elevated in carcinoma in situ compared to the normal epithelium, whereas it is drastically ablated in cancer cells within hypoxic niches, which promotes epithelial to mesenchymal transition (EMT).

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Background: Papaverine is a benzylisoquinoline alkaloid from the plant Papaver somniferum (Opium poppy). It is approved as an antispasmodic drug by the US FDA and is also reported to have anti-cancer properties. Here, Papaverine's activity in chronic myeloid leukemia (CML) is explored using Saccharomyces cerevisiae, mammalian cancer cell lines, and in silico studies.

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Maintenance of oxygen homeostasis is an indispensable criterion for the existence of multicellular life-forms. Disruption of this homeostasis due to inadequate oxygenation of the respiring tissues leads to pathological hypoxia, which acts as a significant stressor in several pathophysiological conditions including cancer, cardiovascular defects, bacterial infections, and neurological disorders. Consequently, the hypoxic tissues develop necessary adaptations both at the tissue and cellular level.

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Hypoxic microenvironment heralds epithelial-mesenchymal transition (EMT), invasion and metastasis in solid tumors. Deregulation of alternative splicing (AS) of several cancer-associated genes has been instrumental in hypoxia-induced EMT. Our study in breast cancer unveils a previously unreported mechanism underlying hypoxia-mediated AS of a crucial cytoskeleton remodeler during EMT.

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CREB signaling is known for several decades, but how it regulates both positive and negative regulators of cell proliferation is not well understood. On the other hand functions of major epigenetic repressors such as DNMT3B, EZH2 and CUL4B for their repressive epigenetic modifications on chromatin have also been well studied. However, there is very limited information available on how these repressors are regulated at their transcriptional level.

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Epigenetic modifications govern gene expression by guiding the human genome on 'what to express and what not to'. DNA methyltransferases (DNMTs) establish methylation patterns on DNA, particularly in CpG islands, and such patterns play a major role in gene silencing. DNMTs are a family of proteins/enzymes (DNMT1, 2, 3A, 3B, and 3L), among which, DNMT1 (maintenance methyltransferase) and DNMT3 (de novo methyltransferases) that direct mammalian development and genome imprinting are highly investigated.

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CUL4A; an E3 ubiquitin ligase is involved in the degradation of negative regulators of cell cycle such as p21, p27, p53, etc., through polyubiquitination-mediated protein degradation. The functional role(s) of CUL4A proteins on their targets are well characterized; however, the transcriptional regulation of CUL4A, particularly at its promoter level is not yet studied.

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