DNA ligase 1 (LIG1) plays a key role in DNA synthesis and DNA damage repair pathways. LIG1 has been shown to be up-regulated in human non-small cell lung cancer (NSCLC); however, its role and molecular regulatory mechanism in NSCLC cell proliferation are still not fully understand. In this study, we aimed to explore the role of LIG1 and post-transcripional regulators in NSCLC. Utilizing bioinformatic tools and qRT-PCR, our investigation substantiated the up-regulation of LIG1 within NSCLC cell lines and tumour tissues. Remarkably, individuals exhibiting elevated levels of LIG1 had diminished survival rates. Functionally, the depletion of LIG1 inhibited cell proliferation and migration, contrasting with the increased proliferation and migration upon LIG1 over-expression. Prediction from the TargetScanHuman database and results of dual luciferase reporter assays indicated that miR-325 could directly bind to and negatively regulate LIG1. Moreover, our findings demonstrated that the mimicry of miR-325 decreased cell viability, whereas its inhibition correspondingly increased viability, indicative of the tumour-suppressive role of miR-325 through the down-regulation of LIG1. Collectively, our findings show that LIG1 could promote tumour progression and knockdown of LIG1 could exert suppressive effects on NSCLC. As the post-transcriptional factor of LIG1, miR-325 could negatively regulate the expression of LIG1 to inhibit tumour progression in vitro. These findings suggest that LIG1 and miR-325 might be potential therapeutic targets for NSCLC treatment.
- MeSH
- DNA Ligase ATP * metabolism genetics MeSH
- Humans MeSH
- MicroRNAs * genetics metabolism MeSH
- Cell Line, Tumor MeSH
- Lung Neoplasms * pathology genetics metabolism MeSH
- Carcinoma, Non-Small-Cell Lung * genetics pathology metabolism MeSH
- Cell Movement * MeSH
- Cell Proliferation * MeSH
- Gene Expression Regulation, Neoplastic MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Replication forks stalled at co-transcriptional R-loops can be restarted by a mechanism involving fork cleavage-religation cycles mediated by MUS81 endonuclease and DNA ligase IV (LIG4), which presumably relieve the topological barrier generated by the transcription-replication conflict (TRC) and facilitate ELL-dependent reactivation of transcription. Here, we report that the restart of R-loop-stalled replication forks via the MUS81-LIG4-ELL pathway requires senataxin (SETX), a helicase that can unwind RNA:DNA hybrids. We found that SETX promotes replication fork progression by preventing R-loop accumulation during S-phase. Interestingly, loss of SETX helicase activity leads to nascent DNA degradation upon induction of R-loop-mediated fork stalling by hydroxyurea. This fork degradation phenotype is independent of replication fork reversal and results from DNA2-mediated resection of MUS81-cleaved replication forks that accumulate due to defective replication restart. Finally, we demonstrate that SETX acts in a common pathway with the DEAD-box helicase DDX17 to suppress R-loop-mediated replication stress in human cells. A possible cooperation between these RNA/DNA helicases in R-loop unwinding at TRC sites is discussed.
- MeSH
- Flap Endonucleases metabolism genetics MeSH
- DEAD-box RNA Helicases * metabolism genetics MeSH
- DNA-Binding Proteins * metabolism genetics MeSH
- DNA Helicases * metabolism genetics MeSH
- DNA Ligase ATP metabolism genetics MeSH
- DNA metabolism genetics MeSH
- Endonucleases * metabolism genetics MeSH
- Transcription, Genetic MeSH
- Humans MeSH
- Multifunctional Enzymes * metabolism genetics MeSH
- R-Loop Structures * MeSH
- DNA Replication * MeSH
- RNA Helicases * metabolism genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Hyperhomocysteinemia (HHcy) is considered an independent risk factor of cardiovascular diseases. Among the proposed mechanisms underlying homocysteine toxicity are altered protein expression and induction of oxidative stress. In the present study, we explored protein abundance and parameters related to oxidative stress in heart homogenates of rats exposed to chronic mild HHcy. Using two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry 22 altered proteins (6 upregulated and 14 downregulated) were identified. For eight proteins the altered abundances were validated by Western blot analysis. Identified proteins are primarily involved in energy metabolism (mainly enzymes of glycolysis, pyruvate dehydrogenase complex, citric acid cycle, and ATP synthase), cardiac muscle contraction (alpha-actin and myosin light chains), stress response (heat-shock protein beta1 and alphaB-crystallin) and antioxidant defense (glutathione peroxidase 1). Diminished antioxidant defense was confirmed by decreases in total antioxidant capacity and GSH/GSSG ratio. Consistent with the decline in enzymatic and non-enzymatic antioxidant defense the protein oxidative modification, as determined by tyrosine nitration, was significantly increased. These findings suggest that both, altered protein expression and elevated oxidative stress contribute to cardiovascular injury caused by HHcy. Keywords: Homocysteine, Heart, Protein abundance, Antioxidant capacity, Nitrotyrosines.
- MeSH
- Hyperhomocysteinemia * metabolism MeSH
- Rats MeSH
- Myocardium * metabolism MeSH
- Oxidative Stress * MeSH
- Rats, Wistar * MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Mitochondrial oxidative phosphorylation (OXPHOS) fuels cellular ATP demands. OXPHOS defects lead to severe human disorders with unexplained tissue specific pathologies. Mitochondrial gene expression is essential for OXPHOS biogenesis since core subunits of the complexes are mitochondrial-encoded. COX14 is required for translation of COX1, the central mitochondrial-encoded subunit of complex IV. Here we describe a COX14 mutant mouse corresponding to a patient with complex IV deficiency. COX14M19I mice display broad tissue-specific pathologies. A hallmark phenotype is severe liver inflammation linked to release of mitochondrial RNA into the cytosol sensed by RIG-1 pathway. We find that mitochondrial RNA release is triggered by increased reactive oxygen species production in the deficiency of complex IV. Additionally, we describe a COA3Y72C mouse, affected in an assembly factor that cooperates with COX14 in early COX1 biogenesis, which displays a similar yet milder inflammatory phenotype. Our study provides insight into a link between defective mitochondrial gene expression and tissue-specific inflammation.
- MeSH
- Cyclooxygenase 1 * MeSH
- DEAD Box Protein 58 MeSH
- DEAD-box RNA Helicases metabolism genetics MeSH
- Liver * metabolism pathology MeSH
- Humans MeSH
- Membrane Proteins MeSH
- Mitochondrial Proteins metabolism genetics MeSH
- Mitochondria metabolism MeSH
- Mutation MeSH
- Mice, Inbred C57BL MeSH
- Mice MeSH
- Oxidative Phosphorylation * MeSH
- Protein Biosynthesis MeSH
- Reactive Oxygen Species * metabolism MeSH
- Electron Transport Complex IV * metabolism genetics MeSH
- RNA, Mitochondrial genetics metabolism MeSH
- Inflammation * metabolism genetics pathology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Disorders of ATP synthase, the key enzyme in mitochondrial energy supply, belong to the most severe metabolic diseases, manifesting as early-onset mitochondrial encephalo-cardiomyopathies. Since ATP synthase subunits are encoded by both mitochondrial and nuclear DNA, pathogenic variants can be found in either genome. In addition, the biogenesis of ATP synthase requires several assembly factors, some of which are also hotspots for pathogenic variants. While variants of MT-ATP6 and TMEM70 represent the most common cases of mitochondrial and nuclear DNA mutations respectively, the advent of next-generation sequencing has revealed new pathogenic variants in a number of structural genes and TMEM70, sometimes with truly peculiar genetics. Here we present a systematic review of the reported cases and discuss biochemical mechanisms, through which they are affecting ATP synthase. We explore how the knowledge of pathophysiology can improve our understanding of enzyme biogenesis and function. Keywords: Mitochondrial diseases o ATP synthase o Nuclear DNA o Mitochondrial DNA o TMEM70.
- MeSH
- Phenotype * MeSH
- Humans MeSH
- Membrane Proteins genetics metabolism MeSH
- DNA, Mitochondrial genetics MeSH
- Mitochondrial Diseases genetics enzymology MeSH
- Mitochondrial Proteins genetics metabolism MeSH
- Mitochondrial Proton-Translocating ATPases * genetics metabolism MeSH
- Mitochondria enzymology genetics MeSH
- Mutation MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
- Systematic Review MeSH
Endogenous opioid peptides serve as potent analgesics through the opioid receptor (OR) activation. However, they often suffer from poor metabolic stability, low lipophilicity, and low blood-brain barrier permeability. Researchers have developed many strategies to overcome the drawbacks of current pain medications and unwanted biological effects produced by the interaction with opioid receptors. Here, we tested multifunctional enkephalin analogs LYS739 (MOR/DOR agonist and KOR partial antagonist) and LYS744 (MOR/DOR agonist and KOR full antagonist) under in vivo conditions in comparison with MOR agonist, morphine. We applied 2D electrophoretic resolution to investigate differences in proteome profiles of crude membrane (CM) fractions isolated from the rat brain cortex and hippocampus exposed to the drugs (10 mg/kg, seven days). Our results have shown that treatment with analog LYS739 induced the most protein changes in cortical and hippocampal samples. The identified proteins were mainly associated with energy metabolism, cell shape and movement, apoptosis, protein folding, regulation of redox homeostasis, and signal transduction. Among these, the isoform of mitochondrial ATP synthase subunit beta (ATP5F1B) was the only protein upregulation in the hippocampus but not in the brain cortex. Contrarily, the administration of analog LYS744 caused a small number of protein alterations in both brain parts. Our results indicate that the KOR full antagonism, together with MOR/DOR agonism of multifunctional opioid ligands, can be beneficial in treating chronic pain states by reducing changes in protein expression levels but retaining analgesic efficacy.
- MeSH
- Analgesics MeSH
- Enkephalins metabolism MeSH
- Hippocampus metabolism MeSH
- Rats MeSH
- Morphine * pharmacology MeSH
- Brain metabolism MeSH
- Analgesics, Opioid pharmacology MeSH
- Receptors, Opioid, mu * metabolism MeSH
- Receptors, Opioid metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Mycobacterial ATP synthase is a validated therapeutic target for combating drug-resistant tuberculosis. Inhibition of this enzyme has been featured as an efficient strategy for the development of new antimycobacterial agents against drug-resistant pathogens. In this study, we synthesised and explored two distinct series of squaric acid analogues designed to inhibit mycobacterial ATP synthase. Among the extensive array of compounds investigated, members of the phenyl-substituted sub-library emerged as primary hits. To gain deeper insights into their mechanisms of action, we conducted advanced biological studies, focusing on the compounds displaying a direct binding of a nitrogen heteroatom to the phenyl ring, resulting in the highest potency. Our investigations into spontaneous mutants led to the validation of a single point mutation within the atpB gene (Rv1304), responsible for encoding the ATP synthase subunit a. This genetic alteration sheds light on the molecular basis of resistance to squaramides. Furthermore, we explored the possibility of synergy between squaramides and the reference drug clofazimine using a checkerboard assay, highlighting the promising avenue for enhancing the effectiveness of existing treatments through combined therapeutic approaches. This study contributes to the expansion of investigating squaramides as promising drug candidates in the ongoing battle against drug-resistant tuberculosis.
- MeSH
- Adenosine Triphosphate metabolism MeSH
- Antitubercular Agents chemistry MeSH
- Humans MeSH
- Mitochondrial Proton-Translocating ATPases chemistry metabolism MeSH
- Tuberculosis, Multidrug-Resistant * MeSH
- Mycobacterium tuberculosis * MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The long slender bloodstream form Trypanosoma brucei maintains its essential mitochondrial membrane potential (ΔΨm) through the proton-pumping activity of the FoF1-ATP synthase operating in the reverse mode. The ATP that drives this hydrolytic reaction has long been thought to be generated by glycolysis and imported from the cytosol via an ATP/ADP carrier (AAC). Indeed, we demonstrate that AAC is the only carrier that can import ATP into the mitochondrial matrix to power the hydrolytic activity of the FoF1-ATP synthase. However, contrary to expectations, the deletion of AAC has no effect on parasite growth, virulence or levels of ΔΨm. This suggests that ATP is produced by substrate-level phosphorylation pathways in the mitochondrion. Therefore, we knocked out the succinyl-CoA synthetase (SCS) gene, a key mitochondrial enzyme that produces ATP through substrate-level phosphorylation in this parasite. Its absence resulted in changes to the metabolic landscape of the parasite, lowered virulence, and reduced mitochondrial ATP content. Strikingly, these SCS mutant parasites become more dependent on AAC as demonstrated by a 25-fold increase in their sensitivity to the AAC inhibitor, carboxyatractyloside. Since the parasites were able to adapt to the loss of SCS in culture, we also analyzed the more immediate phenotypes that manifest when SCS expression is rapidly suppressed by RNAi. Importantly, when performed under nutrient-limited conditions mimicking various host environments, SCS depletion strongly affected parasite growth and levels of ΔΨm. In totality, the data establish that the long slender bloodstream form mitochondrion is capable of generating ATP via substrate-level phosphorylation pathways.
Background: Native chickens are dispersed in a wide geographical range and have hereditary assets that are kept by farmers for various purposes. Mitochondrial DNA (mtDNA) is a widely utilized marker in molecular studies because of its quick advancement, matrilineal legacy, and simple molecular structure. Method and Results: We performed NGS sequencing to investigate mitochondrial genomes and to evaluate the hereditary connections, diversity, and measure of gene stream estimation in Indian native chicken breeds and Red Jungle fowl. The chicken breeds were genotyped using the D-loop region and 23 haplotypes were identified. When compared to Indian native breeds, more haplotypes were identified in the NADH dehydrogenase subunits, Cytochrome c oxidase, Cytochrome b, ATP synthase subunit 6, and Ribosomal RNA genes. The phylogenetic examination indicated that the analyzed chicken breeds were divided into six significant clades, namely A, B, C, D, E, and F, of which the F clade indicated the domestication of chicken breeds in India. Additionally, our work affirmed that the Indian Red Jungle Fowl is the origin for both reference Red Jungle Fowl as well as all Indian breeds, which is reflected in the dendrogram as well as network analysis based on the whole mtDNA and D-loop region. Indian Red Jungle Fowl is distributed as an outgroup, suggesting that this ancestry was reciprocally monophyletic. Conclusion: The mtDNA sequences of Indian native chickens provided novel insights into adaptation mechanisms and the significance of important mtDNA variations in understanding the maternal lineages of native birds.
- Publication type
- Journal Article MeSH
Disruption of adipocyte de novo lipogenesis (DNL) by deletion of fatty acid synthase (FASN) in mice induces browning in inguinal white adipose tissue (iWAT). However, adipocyte FASN knockout (KO) increases acetyl-coenzyme A (CoA) and malonyl-CoA in addition to depletion of palmitate. We explore which of these metabolite changes triggers adipose browning by generating eight adipose-selective KO mouse models with loss of ATP-citrate lyase (ACLY), acetyl-CoA carboxylase 1 (ACC1), ACC2, malonyl-CoA decarboxylase (MCD) or FASN, or dual KOs ACLY/FASN, ACC1/FASN, and ACC2/FASN. Preventing elevation of acetyl-CoA and malonyl-CoA by depletion of adipocyte ACLY or ACC1 in combination with FASN KO does not block the browning of iWAT. Conversely, elevating malonyl-CoA levels in MCD KO mice does not induce browning. Strikingly, adipose ACC1 KO induces a strong iWAT thermogenic response similar to FASN KO while also blocking malonyl-CoA and palmitate synthesis. Thus, ACC1 and FASN are strong suppressors of adipocyte thermogenesis through promoting lipid synthesis rather than modulating the DNL intermediates acetyl-CoA or malonyl-CoA.
- MeSH
- Acetyl-CoA Carboxylase * metabolism MeSH
- Acetyl Coenzyme A metabolism MeSH
- Mice, Knockout MeSH
- Mice MeSH
- Palmitates metabolism MeSH
- Fatty Acid Synthases metabolism MeSH
- Thermogenesis MeSH
- Adipocytes * metabolism MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, N.I.H., Extramural MeSH
