Mitochondrial ROS triggers mitophagy through activating DNA damage response signaling pathway
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo Sapiens
SUBMITTER: 
Liu Cao
PROVIDER: PXD058451 | iProX | Fri Nov 29 00:00:00 GMT 2024
REPOSITORIES: iProX
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Project description:Faithful genome integrity maintenance plays an essential role in cell survival. Here, we identify the RNA demethylase ALKBH5 as a key regulator that protects cells from DNA damage and apoptosis during reactive oxygen species (ROS)-induced stress. We find that ROS significantly induces global mRNA N6-methyladenosine (m6A) levels by modulating ALKBH5 post-translational modifications (PTMs), leading to the rapid and efficient induction of thousands of genes involved in a variety of biological processes including DNA damage repair. Mechanistically, ROS promotes ALKBH5 SUMOylation through activating ERK/JNK signaling, leading to inhibition of ALKBH5 m6A demethylase activity by blocking substrate accessibility. Moreover, ERK/JNK/ALKBH5-PTMs/m6A axis is activated by ROS in hematopoietic stem/progenitor cells (HSPCs) in vivo in mice, suggesting a physiological role of this molecular pathway in the maintenance of genome stability in HSPCs. Together, our study uncovers a molecular mechanism involving ALKBH5 PTMs and increased mRNA m6A levels that protect genomic integrity of cells in response to ROS.
2021-04-29 | GSE144620 | GEO
Project description:Reactive oxygen species (ROS) are a group of short-lived, highly reactive, oxygen-containing molecules that can induce DNA damage and affect the DNA damage response (DDR). There is unequivocal pre-clinical and clinical evidence that ROS influence the genotoxic stress caused by chemotherapeutics agents and ionizing radiation. Recent studies have provided mechanistic insight into how ROS can also influence the cellular response to DNA damage caused by genotoxic therapy, especially in the context of Double Strand Breaks (DSBs). This has led to the clinical evaluation of agents modulating ROS in combination with genotoxic therapy for cancer, with mixed success so far. These studies point to context dependent outcomes with ROS modulator combinations with Chemotherapy and radiotherapy, indicating a need for additional pre-clinical research in the field. In this review, we discuss the current knowledge on the effect of ROS in the DNA damage response, and its clinical relevance.
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Project description:As essential regulators of mitochondrial quality control, mitochondrial dynamics and mitophagy play key roles in maintenance of metabolic health and cellular homeostasis. Here we show that knockdown of the membrane-inserted scaffolding and structural protein caveolin-1 (Cav-1) and expression of tyrosine 14 phospho-defective Cav-1 mutant (Y14F), as opposed to phospho-mimicking Y14D, altered mitochondrial morphology, and increased mitochondrial matrix mixing, mitochondrial fusion and fission dynamics as well as mitophagy in MDA-MB-231 triple negative breast cancer cells. Further, we found that interaction of Cav-1 with mitochondrial fusion/fission machinery Mitofusin 2 (Mfn2) and Dynamin related protein 1 (Drp1) was enhanced by Y14D mutant indicating Cav-1 Y14 phosphorylation prevented Mfn2 and Drp1 translocation to mitochondria. Moreover, limiting mitochondrial recruitment of Mfn2 diminished formation of the PINK1/Mfn2/Parkin complex required for initiation of mitophagy resulting in accumulation of damaged mitochondria and ROS (mtROS). Thus, these studies indicate that phospho-Cav-1 may be an important switch mechanism in cancer cell survival which could lead to novel strategies for complementing cancer therapies.
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Project description:Many organisms respond to DNA damage by inducing expression of DNA repair genes. We find that the human stomach pathogen Helicobacter pylori instead induces transcription and translation of natural competence genes, thus increasing transformation frequency. Transcription of a lysozyme-like protein that promotes DNA donation from intact cells is also induced. Exogenous DNA modulates the DNA damage response, as both recA and the ability to take up DNA are required for full induction of the response. This feedback loop is active during stomach colonization, indicating a role in the pathogenesis of the bacterium. As patients can be infected with multiple genetically distinct clones of H. pylori, DNA damage induced genetic exchange may facilitate spread of antibiotic resistance and selection of fitter variants through re-assortment of preexisting alleles in this important human pathogen.
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Project description:BackgroundPolydatin (3,4',5-trihydroxy-3-β-d-glucopyranoside, PD) is known for its antioxidant and anti-inflammatory properties. Oxaliplatin (OXA)-based chemotherapy is the first-line treatment for metastatic and recurrent colorectal cancer (CRC). However, the lack of selectivity for normal cells often results in side effects. Consequently, the search for anti-cancer components with high efficacy and low cytotoxicity has become a significant focus in recent years.MethodsThe anti-tumor effects of PD, OXA or their combination were assessed by cell viability, colony formation, and wound-healing assays. Reactive oxygen species (ROS) generation was measured by flow cytometry and DNA damage was assessed by immunofluorescence assay. The relative gene and protein expressions were analyzed by quantitative real time-PCR (qRT-PCR) and Western blot assays. Molecular docking analysis predicted the interaction between PD and potential targets.ResultsWe found that PD exerted anti-CRC activity by promoting Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase 5 (NOX5)-mediated ROS production, activating the endoplasmic reticulum (ER) stress, and inducing DNA damage. Knocking down NOX5 attenuated the inhibition of proliferation and colony forming ability induced by PD in colon cancer cells and reversed the expression of C/EBP-homologous protein (CHOP) and activating transcription factor 4 (ATF4) proteins. In addition, combination of PD and OXA synergistically exerted anti-CRC activities by promoting DNA damage and activating ER stress signaling pathway.ConclusionThe combination of PD and OXA could be an effective treatment strategy for certain patients with CRC.
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