Biochimica et biophysica acta. Molecular basis of disease最新文献

Background: Traumatic brain injury (TBI) is a major public health concern with high morbidity and mortality rates. Secondary brain injury, marked by inflammatory responses and apoptosis, worsens TBI outcomes. The endoplasmic reticulum stress (ERS) response has been implicated in secondary brain injury, with Glutamine Rich 1 Gene (QRICH1) emerging as a potential mediator. However, the precise role of QRICH1 in TBI pathogenesis and its therapeutic implications remain unclear.

Methods: Controlled cortical impact mouse and Lipopolysaccharide-stimulated primary neuron models were used. Behavioral assessments, including the modified Garcia score, Y-maze test, and open-field test, were used to evaluate postoperative recovery in mice. QRICH1 neuron conditional knockout (cKO) mice were used to assess QRICH1 function, whereas adeno-associated virus (AAV)-mediated gene manipulation was used to modulate QRICH1 expression in cortical neurons.

Results: QRICH1 expression was upregulated in the brain tissue of TBI mice, particularly 24 h post-injury, as shown by western blot analysis and immunofluorescence staining. QRICH1 is localized within neuronal nuclei, suggesting a role in cellular stress responses. QRICH1 cKO improved behavioral outcomes post-TBI, whereas AAV-mediated QRICH1 overexpression exacerbated secondary brain injury, characterized by increased ERS-related protein expression and neuronal death. Conversely, AAV-mediated QRICH1 knockdown reduced secondary brain injury as evidenced by decreased ERS-related protein expression and neuronal death.

Conclusion: QRICH1 plays a critical role in exacerbating ERS and apoptosis, and influences neuronal fate in secondary brain injury. Its involvement in the ERS pathway and in the induction of neuronal apoptosis post-TBI highlights QRICH1 as a potential therapeutic target for TBI treatment.

Inflammatory Bowel Diseases (IBDs) are chronic inflammatory disorders of the gastrointestinal tract and colon affecting approximately 7 million individuals worldwide. The knowledge of specific pathology and aetiological mechanisms leading to IBD is limited, however a reduced immune system, antibiotic use and reserved diet may initiate symptoms. Dysbiosis of the gut microbiome, and consequently a varied composition of the metabolome, has been extensively linked to these risk factors and IBD. Metagenomic sequencing and liquid-chromatography mass spectrometry (LC-MS) of N = 220 fecal samples by Fransoza et al., provided abundance data on microbial genera and metabolites for use in this study. Identification of differentially abundant microbes and metabolites was performed using a Wilcoxon test, followed by feature selection of random forest (RF), gradient-boosting (XGBoost) and least absolute shrinkage operator (LASSO) models. The performance of these features was then validated using RF models on the Human Microbiome Project 2 (HMP2) dataset and a microbial community (MICOM) model was utilised to predict and interpret the interactions between key microbes and metabolites. The Flavronifractor genus and microbes of the families Lachnospiraceae and Oscillospiraceae were found differential by all models. Metabolic pathways commonly influenced by such microbes in IBD were CoA biosynthesis, bile acid metabolism and amino acid production and degradation. This study highlights distinct interactive microbiome and metabolome profiles within IBD and the highly potential pathways causing disease pathology. It therefore paves way for future investigation into new therapeutic targets and non-invasive diagnostic tools for IBD.

Alzheimer's disease (AD) poses a considerable worldwide health obstacle, marked by gradual cognitive deterioration and neuronal loss. While the molecular mechanisms underlying AD pathology have been elucidated to some extent, therapeutic options remain limited. Mitochondrial dysfunction has become recognized as a significant factor in the development of AD, with oxidative stress and disrupted energy metabolism being critical elements. This review explores the mechanistic aspects of small molecule targeting of mitochondria as a potential therapeutic approach for AD. The review explores the role of mitochondrial dysfunction in AD, including its involvement in the accumulation of β-amyloid plaques and neurofibrillary tangles, synaptic dysfunction, and neuronal death. Furthermore, the effects of oxidative stress on mitochondrial function were investigated, including the resulting damage to mitochondrial components. Mitochondrial-targeted therapies have attracted attention for their potential to restore mitochondrial function and reduce AD pathology. The review outlines the latest preclinical and clinical evidence supporting the effectiveness of small molecules in targeting mitochondrial dysfunction in AD. Additionally, it discusses the molecular pathways involved in mitochondrial dysfunction and examines how small molecules can intervene to address these abnormalities. By providing a comprehensive overview of the latest research in this field, this review aims to shed light on the therapeutic potential of small molecule targeting of mitochondria in AD and stimulate further research in this promising area of drug development.

Acute pancreatitis (AP) is a severe inflammatory disorder associated with metabolic reprogramming and mitochondrial dysfunction. This study investigated central carbon metabolism alterations in pancreatic acinar cells during AP, elucidated the molecular mechanisms of tricarboxylic acid (TCA) cycle disorders, and explored the role of protein hypersuccinylation in AP pathogenesis. Using in vitro and in vivo AP models, targeted metabolomics and bioinformatics analyses revealed TCA cycle dysregulation characterized by elevated succinyl-CoA and decreased succinate levels. Colorimetric assays, mass spectrometry, and site-directed mutagenesis demonstrated that SIRT5 downregulation led to SUCLA2 hypersuccinylation at K118, inhibiting succinyl-CoA synthetase activity and triggering a vicious cycle of succinyl-CoA accumulation and SUCLA2 succinylation. Adenovirus-mediated SIRT5 overexpression and SUCLA2 knockdown clarified the SIRT5-SUCLA2 pathway's role in regulating TCA cycle disorders. Protein succinylation levels positively correlated with pancreatic tissue damage and mitochondrial injury severity. Succinylome analysis identified cytochrome c1 (CYC1) as a key hypersuccinylated protein, and the SIRT5-SUCLA2 pathway regulated its succinylation level and electron transport chain complex III activity. Hypersuccinylation induced mitochondrial DNA release, activating the cGAS-STING pathway, contributing to multiple organ dysfunction syndrome. Modulating the SIRT5-SUCLA2 axis attenuated TCA cycle dysregulation, protein hypersuccinylation, mitochondrial damage, and inflammatory responses in AP. These findings reveal novel mechanisms linking the SIRT5-SUCLA2 axis, TCA cycle dysfunction, and protein hypersuccinylation in AP pathogenesis, providing potential therapeutic targets for AP treatment.

Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome associated with a highly penetrant cancer spectrum characterized by germline TP53 mutations. We characterized the first LFS zebrafish hotspot mutants, tp53 R217H and R242H (human R248H and R273H), and found these mutants exhibit partial-to-no activation of p53 target genes, have defective cell-cycle checkpoints, and display partial-to-full resistance to apoptosis, although the R217H mutation has hypomorphic characteristics. Spontaneous tumor development histologically resembling human sarcomas was observed as early as 6 months. tp53 R242H mutants had a higher lifetime tumor incidence compared to tp53 null and R217H mutants, suggesting it is a more aggressive mutation. We observed mutation-specific tumor phenotypes across tp53 mutants with associated diverse transcriptomic and DNA methylome profiles in tp53 mutant larvae, impacting metabolism, cell signalling, and biomacromolecule synthesis and degradation. These tp53 zebrafish mutants demonstrate fidelity to their human counterparts and provide new insights into underlying tumorigenesis mechanisms and kinetics that suggest metabolic rewiring and cellular signalling changes occur prior to tumor initiation, which will guide targeted therapeutics for LFS.

Objectives: To understand the mechanism by which colchicine inhibits the inflammatory properties of monosodium urate (MSU) crystal deposits and tophi.

Methods: We investigated the effects of colchicine on the inflammatory properties of monosodium urate (MSU) crystal deposits in several models: (i) In vitro tophus formation by MSU and neutrophils; (ii) MSU-induced peritonitis model; (iii) Alpha-1-antitrypsin-induced peritoneal MSU flare model; (iv) MSU-induced arthritis model. We measured neutrophil numbers, NET formation, IL-1β production and F-actin generation by MSU crystals. In addition, we tested the effect of actin inhibitors SMIFH2, Cytochalasin B and Latrunculin B in the models.

Results: Colchicine did not affect neutrophil numbers in all these models. However, colchicine was highly effective to inhibit NET formation, IL-1β production and F-actin generation indicating less pronounced tophus formation, lower inflammatory properties of tophi and reduced conversion from G-actin into F-actin, respectively. F-actin was shown to accumulate in tophi without presence of colchicine and being resistant to degradation by DNase I. Actin inhibitors SMIFH2 and Cytochalasin B significantly reduced IL-1β and neutrophil elastase levels and mitigated MSU-induced arthritis.

Conclusion: Colchicine effects on gout flares are not based on reducing neutrophil numbers but on changing the functional properties of tophi by reducing their DNase-resistant F-actin concentrations and thereby reducing the negative impact of NETs on IL-1β production and the pro-inflammatory state of tophi. Actin inhibitors may be interesting tools to convey anti-inflammatory properties and reduction of flares in gout patients.

Retinoic acid (RA) is a small, lipophilic molecule that inhibits cell proliferation and induces differentiation through activation of a family of nuclear receptors (RARs). The therapeutic potential of RA in the treatment of glioma was first evaluated two decades ago, but these attempts were considered not conclusive. Based on the complexity of tumor microenvironment and the role of purinergic signals within TME, we aimed to support RA-induced alterations in glioma cells with extracellular ATP. Our experiments focused on defining the purinergic signaling dynamics of two different human glioma cell lines M059K and M059J subjected to RA-based differentiation protocol. The applied procedure caused considerable modulation in P2X7 receptor variants expression at the gene and protein level, and decrease in ecto-nucleotidase activity. Collectively, it led to the decrease in cell proliferation rate and migration, as well as boosted sensitivity to cytotoxic eATP influence. We confirmed that micromolar concentrations of ATP decreased cell viability by 40 and 20 % in RA-treated M059K and M059J cells, respectively. Moreover, the decrease in migration capability up to 60 % in the presence of 100 μM ATP was observed. Both effects were mediated by P2X7R activation and reversed in the presence of A740003 antagonist, confirming the role of P2X7 receptor. We postulate that retinoic acid-induced changes coupled with micromolar eATP could be effective as anti-cancer treatment affecting the purinergic signaling. The obtained results point out the role of P2X7R variants in influencing potential of glioma cells, as well as the possibility of using these isoforms as therapeutic targets.

Hemoglobin (Hb) releases during hemorrhaging and causes oxidative damage, further exacerbates the development of multiple diseases. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defenses against toxic and oxidative challenges. However, the regulation mechanism of Nrf2 in Hb-induced oxidative stress remains unclear in teleost. To accomplish this goal, a hemolysis model was established by injecting grass carp with phenylalanine (PHZ), and the immunofluorescence analysis (IFA) and hematoxylin and eosin (H&E) staining revealed that PHZ-induced hemolysis caused Hb accumulation and hepatic vacuolization, resulted in tissue damage. Prussian blue, Sirius red, and Masson staining results revealed significant iron deposition and extensive collagen fiber accumulation in the liver. IFA and immunohistochemical analyses demonstrated that PHZ-induced hemolysis markedly increased the production of reactive oxygen species (ROS), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE). The quantitative real-time PCR (qRT-PCR) analysis data revealed that the PHZ-induced hemolysis also significantly upregulated the expression of antioxidant-related genes through activation of the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/Nrf2 signaling pathway. To further explore the molecule regulation mechanism of PHZ-induced hemolysis, the RNA-seq analysis was performed, and the data revealed that the AMPK/Nrf2 and multiple programmed cell death pathways, including ferroptosis, autophagy, apoptosis, and necroptosis in PHZ injection groups were significant upregulated. In vitro, the hemin supplementation activated the expression of target genes in the AMPK/Nrf2 pathway detected by qRT-PCR. To further verify the regulation function of Nrf2, an Nrf2 activator (4OI) was supplemented, and the flow cytometer analysis results suggested that the Hb-induced cell damage was significantly attenuated. However, the supplementary of ML385 down-regulated the AMPK/Nrf2 pathway and aggravated the hemin induced cell death. In conclusion, these findings highlight the critical regulatory role of the AMPK/Nrf2 signaling pathway in protecting against Hb-induced oxidative damage in the liver of grass carp.

It becomes increasingly clear that the tissue specificity of mitochondrial diseases might in part rely on their ability to compensate for mitochondrial defects, contributing to the heterogeneous nature of mitochondrial diseases. Here, we investigated tissue-specific responses to cytochrome c oxidase (CIV or COX) deficiency using a mouse model with heart and skeletal muscle-specific depletion of the COX assembly factor COX10. At three weeks of age, both tissues exhibit pronounced CIV depletion but respond differently to oxidative phosphorylation (OXPHOS) impairment. Heart-specific COX10 depletion caused severe dilated cardiomyopathy, while skeletal muscle experiences less damage. Cardiac CIV deficiency triggered extensive metabolic remodelling and stress response activation, potentially worsening cardiomyopathy, whereas skeletal muscle showed no stress response or significant metabolic changes. Our findings highlight distinct tissue capacities for managing CIV deficiency, explaining how identical primary defects can lead to different phenotypic outcomes and contribute to the heterogeneous progression of mitochondrial diseases.

Idiopathic pulmonary fibrosis (IPF) is a lethal progressive lung disease urgently needing new therapies. Current treatments only delay disease progression, leaving lung transplant as the sole remaining option. Recent studies support a model whereby IPF arises because alveolar epithelial type II (AT2) cells, which normally mediate distal lung regeneration, acquire airway and/or mesenchymal characteristics, preventing proper repair. Mechanisms driving this abnormal differentiation remain unclear. We performed integrated transcriptomic and epigenomic analysis of purified AT2 cells which revealed genome-wide alterations in IPF lungs. The most prominent epigenetic alteration was activation of an enhancer in thyroid receptor interactor 13 (TRIP13), although TRIP13 was not the most significantly transcriptionally upregulated gene. TRIP13 is broadly implicated in epithelial-mesenchymal plasticity. In cultured human AT2 cells and lung slices, small molecule TRIP13 inhibitor DCZ0415 prevented acquisition of the mesenchymal gene signature characteristic of IPF, suggesting TRIP13 inhibition as a potential therapeutic approach to fibrotic disease.