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Frontiers in Cell and Developmental... 2024Mitochondria play a central role in cellular metabolism producing the necessary ATP through oxidative phosphorylation. As a remnant of their prokaryotic past,... (Review)
Review
Mitochondria play a central role in cellular metabolism producing the necessary ATP through oxidative phosphorylation. As a remnant of their prokaryotic past, mitochondria contain their own genome, which encodes 13 subunits of the oxidative phosphorylation system, as well as the tRNAs and rRNAs necessary for their translation in the organelle. Mitochondrial protein synthesis depends on the import of a vast array of nuclear-encoded proteins including the mitochondrial ribosome protein components, translation factors, aminoacyl-tRNA synthetases or assembly factors among others. Cryo-EM studies have improved our understanding of the composition of the mitochondrial ribosome and the factors required for mitochondrial protein synthesis and the advances in next-generation sequencing techniques have allowed for the identification of a growing number of genes involved in mitochondrial pathologies with a defective translation. These disorders are often multisystemic, affecting those tissues with a higher energy demand, and often present with neurodegenerative phenotypes. In this article, we review the known proteins required for mitochondrial translation, the disorders that derive from a defective mitochondrial protein synthesis and the animal models that have been established for their study.
PubMed: 38855161
DOI: 10.3389/fcell.2024.1410245 -
BioRxiv : the Preprint Server For... May 2024Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection,...
Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, parasites internalize and digest abundant host hemoglobin within the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) that lacks key active-site residues and has lost canonical HO activity. The cellular role of this unusual protein that underpins its retention by parasites has been unknown. To unravel PfHO function, we first determined a 2.8 Å-resolution X-ray structure that revealed a highly α-helical fold indicative of distant HO homology. Localization studies unveiled PfHO targeting to the apicoplast organelle, where it is imported and undergoes N-terminal processing but retains most of the electropositive transit peptide. We observed that conditional knockdown of PfHO was lethal to parasites, which died from defective apicoplast biogenesis and impaired isoprenoid-precursor synthesis. Complementation and molecular-interaction studies revealed an essential role for the electropositive N-terminus of PfHO, which selectively associates with the apicoplast genome and enzymes involved in nucleic acid metabolism and gene expression. PfHO knockdown resulted in a specific deficiency in levels of apicoplast-encoded RNA but not DNA. These studies reveal an essential function for PfHO in apicoplast maintenance and suggest that repurposed the conserved HO scaffold from its canonical heme-degrading function in the ancestral chloroplast to fulfill a critical adaptive role in organelle gene expression.
PubMed: 38853871
DOI: 10.1101/2024.05.30.596652 -
Tropical Biomedicine Mar 2024Avian infectious bronchitis (IB), a Gammacoronavirus, is a highly contagious upper respiratory disease, affecting chickens of all ages with a significant economic threat...
Avian infectious bronchitis (IB), a Gammacoronavirus, is a highly contagious upper respiratory disease, affecting chickens of all ages with a significant economic threat to the poultry industry. In February 2020, a specimen of imported chicken meat product was received and requested for coronavirus testing. The result was positive for the avian coronavirus, the IB virus (IBV) by molecular detection in the pre-screening test. Thus, this study aimed to isolate and characterize the IBV from the specimen. Virus isolation via egg inoculation was attempted and IBV was successfully isolated. The S1 subunit of the spike (S) gene of the IBV was amplified, sequenced, and the Basic Local Alignment Search Tool (BLAST) analysis showed that the IBV has 99% and 98% nucleotide similarity with the Malaysian and China IBVs, respectively. The phylogenetic analysis indicated that the virus belongs to the GI-19 lineage (also known as the QX strain) and is grouped with other IBVs from Malaysia and China. The GI-19 lineage is one of the primary IB strains that circulate in Malaysia. The recovery of the virus may be due to the persistence characteristic of the virus on meat; and the cold chain practices in the imported food product prolong the survival of this coronavirus. Though IBV is not identified as a hazard in chicken meat or meat products, raw food should be cooked thoroughly before being consumed. With the increase in international trade in poultry and poultry products, disease screening at the entry point and import risk analysis is crucial to ensure food safety and prevent the introduction of new viruses into Malaysia.
Topics: Animals; Infectious bronchitis virus; Malaysia; Chickens; Phylogeny; Poultry Diseases; Coronavirus Infections; Meat Products; Spike Glycoprotein, Coronavirus
PubMed: 38852131
DOI: 10.47665/tb.41.1.004 -
Nature Communications Jun 2024Tobacco smoking (TS) is implicated in lung cancer (LC) progression through the development of metabolic syndrome. However, direct evidence linking metabolic syndrome to...
Tobacco smoking (TS) is implicated in lung cancer (LC) progression through the development of metabolic syndrome. However, direct evidence linking metabolic syndrome to TS-mediated LC progression remains to be established. Our findings demonstrate that 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene (NNK and BaP; NB), components of tobacco smoke, induce metabolic syndrome characteristics, particularly hyperglycemia, promoting lung cancer progression in male C57BL/6 J mice. NB enhances glucose uptake in tumor-associated macrophages by increasing the expression and surface localization of glucose transporter (GLUT) 1 and 3, thereby leading to transcriptional upregulation of insulin-like growth factor 2 (IGF2), which subsequently activates insulin receptor (IR) in LC cells in a paracrine manner, promoting its nuclear import. Nuclear IR binds to nucleophosmin (NPM1), resulting in IR/NPM1-mediated activation of the CD274 promoter and expression of programmed death ligand-1 (PD-L1). Restricting glycolysis, depleting macrophages, or blocking PD-L1 inhibits NB-mediated LC progression. Analysis of patient tissues and public databases reveals elevated levels of IGF2 and GLUT1 in tumor-associated macrophages, as well as tumoral PD-L1 and phosphorylated insulin-like growth factor 1 receptor/insulin receptor (pIGF-1R/IR) expression, suggesting potential poor prognostic biomarkers for LC patients. Our data indicate that paracrine IGF2/IR/NPM1/PD-L1 signaling, facilitated by NB-induced dysregulation of glucose levels and metabolic reprogramming of macrophages, contributes to TS-mediated LC progression.
Topics: Animals; Lung Neoplasms; Male; Humans; Mice, Inbred C57BL; Receptor, Insulin; Mice; B7-H1 Antigen; Hyperglycemia; Benzo(a)pyrene; Nucleophosmin; Insulin-Like Growth Factor II; Disease Progression; Nuclear Proteins; Nitrosamines; Tumor-Associated Macrophages; Cell Line, Tumor; Paracrine Communication; Gene Expression Regulation, Neoplastic; Smoking; Macrophages
PubMed: 38851766
DOI: 10.1038/s41467-024-49199-9 -
Plant Physiology Jun 2024
PubMed: 38849988
DOI: 10.1093/plphys/kiae310 -
Advanced Drug Delivery Reviews Jun 2024Mitochondrial genome (mtDNA) independent of nuclear gene is a set of double-stranded circular DNA that encodes 13 proteins, 2 ribosomal RNAs and 22 mitochondrial... (Review)
Review
Mitochondrial genome (mtDNA) independent of nuclear gene is a set of double-stranded circular DNA that encodes 13 proteins, 2 ribosomal RNAs and 22 mitochondrial transfer RNAs, all of which play vital roles in functions as well as behaviors of mitochondria. Mutations in mtDNA result in various mitochondrial disorders without available cures. However, the manipulation of mtDNA via the mitochondria-targeted gene delivery faces formidable barriers, particularly owing to the mitochondrial double membrane. Given the fact that there are various transport channels on the mitochondrial membrane used to transfer a variety of endogenous substances to maintain the normal functions of mitochondria, mitochondrial endogenous substance transport-inspired nanomaterials have been proposed for mitochondria-targeted gene delivery. In this review, we summarize mitochondria-targeted gene delivery systems based on different mitochondrial endogenous substance transport pathways. These are categorized into mitochondrial steroid hormones import pathways-inspired nanomaterials, protein import pathways-inspired nanomaterials and other mitochondria-targeted gene delivery nanomaterials. We also review the applications and challenges involved in current mitochondrial gene editing systems. This review delves into the approaches of mitochondria-targeted gene delivery, providing details on the design of mitochondria-targeted delivery systems and the limitations regarding the various technologies. Despite the progress in this field is currently slow, the ongoing exploration of mitochondrial endogenous substance transport and mitochondrial biological phenomena may act as a crucial breakthrough in the targeted delivery of gene into mitochondria and even the manipulation of mtDNA.
PubMed: 38849004
DOI: 10.1016/j.addr.2024.115355 -
Science Advances Jun 2024Loss-of-function mutations in PTEN-induced kinase 1 (PINK1) are a frequent cause of early-onset Parkinson's disease (PD). Stabilization of PINK1 at the translocase of...
Loss-of-function mutations in PTEN-induced kinase 1 (PINK1) are a frequent cause of early-onset Parkinson's disease (PD). Stabilization of PINK1 at the translocase of outer membrane (TOM) complex of damaged mitochondria is critical for its activation. The mechanism of how PINK1 is activated in the TOM complex is unclear. Here, we report that co-expression of human PINK1 and all seven TOM subunits in is sufficient for PINK1 activation. We use this reconstitution system to systematically assess the role of each TOM subunit toward PINK1 activation. We unambiguously demonstrate that the TOM20 and TOM70 receptor subunits are required for optimal PINK1 activation and map their sites of interaction with PINK1 using AlphaFold structural modeling and mutagenesis. We also demonstrate an essential role of the pore-containing subunit TOM40 and its structurally associated subunits TOM7 and TOM22 for PINK1 activation. These findings will aid in the development of small-molecule activators of PINK1 as a therapeutic strategy for PD.
Topics: Protein Kinases; Humans; Mitochondrial Precursor Protein Import Complex Proteins; Mitochondrial Membrane Transport Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Mitochondria; Protein Binding; Enzyme Activation; Models, Molecular; Protein Subunits
PubMed: 38848361
DOI: 10.1126/sciadv.adn7191 -
Cellular and Molecular Life Sciences :... Jun 2024Mitochondria and the endoplasmic reticulum (ER) have a synergistic relationship and are key regulatory hubs in maintaining cell homeostasis. Communication between these... (Review)
Review
Mitochondria and the endoplasmic reticulum (ER) have a synergistic relationship and are key regulatory hubs in maintaining cell homeostasis. Communication between these organelles is mediated by mitochondria ER contact sites (MERCS), allowing the exchange of material and information, modulating calcium homeostasis, redox signalling, lipid transfer and the regulation of mitochondrial dynamics. MERCS are dynamic structures that allow cells to respond to changes in the intracellular environment under normal homeostatic conditions, while their assembly/disassembly are affected by pathophysiological conditions such as ageing and disease. Disruption of protein folding in the ER lumen can activate the Unfolded Protein Response (UPR), promoting the remodelling of ER membranes and MERCS formation. The UPR stress receptor kinases PERK and IRE1, are located at or close to MERCS. UPR signalling can be adaptive or maladaptive, depending on whether the disruption in protein folding or ER stress is transient or sustained. Adaptive UPR signalling via MERCS can increase mitochondrial calcium import, metabolism and dynamics, while maladaptive UPR signalling can result in excessive calcium import and activation of apoptotic pathways. Targeting UPR signalling and the assembly of MERCS is an attractive therapeutic approach for a range of age-related conditions such as neurodegeneration and sarcopenia. This review highlights the emerging evidence related to the role of redox mediated UPR activation in orchestrating inter-organelle communication between the ER and mitochondria, and ultimately the determination of cell function and fate.
Topics: Humans; Unfolded Protein Response; Endoplasmic Reticulum; Oxidation-Reduction; Mitochondria; Signal Transduction; Animals; Endoplasmic Reticulum Stress
PubMed: 38847861
DOI: 10.1007/s00018-024-05286-0 -
JTO Clinical and Research Reports Jun 2024The available approved anticancer drugs for Chinese patients are relatively limited because of China's low participation rate in international clinical trials....
Efficacy and Safety of Anti-Programmed Cell Death Protein 1/Programmed Death-Ligand 1 Antibodies Plus Chemotherapy as First-Line Treatment for NSCLC in the People's Republic of China: a Systematic Review and Meta-Analysis.
INTRODUCTION
The available approved anticancer drugs for Chinese patients are relatively limited because of China's low participation rate in international clinical trials. Therefore, a focus on approved anti-programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) drugs in China is needed. This study aims to assess the heterogeneity of anti-PD-1/PD-L1 antibodies manufactured in China (domestic PD-1/PD-L1) and overseas (imported PD-1/PD-L1) when combined with chemotherapy as the first-line treatment of NSCLC.
METHODS
A systematic search was performed using PubMed, EMBASE, and Cochrane Library of publications up to July 13, 2023. Meta-analysis was applied to compare the efficacy and safety profile between anti-PD-1/PD-L1 antibodies plus chemotherapy (PD-1/PD-L1+Chemo) and chemotherapy alone using STATA software. Pooled hazard ratios for progression-free survival and overall survival, odds ratios for objective response rate, and incidence rate of grade greater than or equal to three treatment-related adverse events with 95% confidence intervals were calculated in the domestic group and imported group by a random-effects model, and the heterogeneity between the two estimates was assessed.
RESULTS
There were 14 eligible clinical studies with a total of 3951 patients involved in this analysis, including eight studies of domestic PD-1/PD-L1+Chemo and six studies of imported PD-1/PD-L1+Chemo. The study revealed that there was no significant difference between domestic and imported PD-1/PD-L1+Chemo in overall survival ( = 0.80), progression-free survival ( = 0.53), and incidence rate of grade greater than or equal to three treatment-related adverse events ( = 0.10). Nevertheless, the objective response rate of imported PD-1/PD-L1+Chemo was significantly higher than that of domestic PD-1/PD-L1+Chemo ( = 0.03).
CONCLUSIONS
Domestic anti-PD-1/PD-L1 antibodies plus chemotherapy were found to have comparable efficacy and safety to those combined with imported anti-PD-1/PD-L1 antibodies based on current evidence.
PubMed: 38846810
DOI: 10.1016/j.jtocrr.2024.100678 -
Life Science Alliance Aug 2024Lipid composition is conserved within sub-cellular compartments to maintain cell function. Lipidomic analyses of liver, muscle, white and brown adipose tissue (BAT)...
Lipid composition is conserved within sub-cellular compartments to maintain cell function. Lipidomic analyses of liver, muscle, white and brown adipose tissue (BAT) mitochondria revealed substantial differences in their glycerophospholipid (GPL) and free cholesterol (FC) contents. The GPL to FC ratio was 50-fold higher in brown than white adipose tissue mitochondria. Their purity was verified by comparison of proteomes with ER and mitochondria-associated membranes. A lipid signature containing PC and FC, calculated from the lipidomic profiles, allowed differentiation of mitochondria from BAT of mice housed at different temperatures. Elevating FC in BAT mitochondria prevented uncoupling protein (UCP) 1 function, whereas increasing GPL boosted it. Similarly, overexpression facilitating mitochondrial FC import inhibited UCP1 function in primary brown adipocytes, whereas a knockdown promoted it. We conclude that the mitochondrial GPL/FC ratio is key for BAT function and propose that targeting it might be a promising strategy to promote UCP1 activity.
Topics: Animals; Uncoupling Protein 1; Mice; Adipose Tissue, Brown; Cholesterol; Mitochondria; Lipidomics; Organ Specificity; Mice, Inbred C57BL; Adipose Tissue, White; Glycerophospholipids; Male; Lipid Metabolism
PubMed: 38843936
DOI: 10.26508/lsa.202402828