Free Radical Biology and Medicine最新文献

Alzheimer's disease (AD) is a gradually progressive neurodegenerative disease with a serious impact on patients' quality of life. However, single-targeted therapies are not currently effective, and there is a need to find pluripotent drugs with multiple properties. This study aimed to characterize the metabolism of neurotransmitters using a targeted metabolomics approach and to identify the major metabolic pathways mainly affected by 6‴-feruloylspinosin (6-FS). The mechanism of action of 6-FS in the treatment of AD was elucidated based on experimental validation. The metabolomics analysis revealed changes in 13 metabolic profiles by the LC-MS/MS, with significant changes in five amino acid-related neurotransmitters identified primarily. Based on the correlations, we found an effect of mTOR inhibition on the above neurotransmitter metabolism. Furthermore, pretreatment with 6-FS activated the AMPK/mTOR signaling pathway, promoting cellular autophagy, regulating oxidative stress homeostasis and inhibiting mitochondrial dysfunction. In short, these comprehensive analysis methods help clarify the preventive mechanism of 6-FS and potential targets in AD and provide the necessary support for developing natural products to prevent AD.

This study investigated the potential of Porphyra derivatives (PD), including Porphyra334, to activate the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in porcine oocytes to enhance oocyte competency and intracellular networks. Conventional methods for manipulating mitochondrial functions and antioxidant pathways often rely upon genetic modifications that are impractical for direct application in humans. We hypothesized that PD serves as a natural regulator of the NRF2 pathway without requiring genetic intervention. To test this hypothesis, brusatol (Bru), a direct NRF2 inhibitor, was used to evaluate the specific role of PD in NRF2-mediated processes. The results demonstrated that PD significantly improved oocyte maturation, blastocyst formation, and mitochondrial function, including subsequent lipid metabolism. PD activates NRF2 and its downstream antioxidant response elements (AREs), whereas Bru inhibits these effects. Co-treatment with PD and Bru resulted in the partial recovery of NRF2 activity. These findings suggest that PD functions as a toggle for NRF2 activation, potentially offering a non-genetic strategy for enhancing oocyte quality and embryo development by modulating antioxidant mechanisms and mitochondrial functions. This study provides new avenues for investigating natural compounds in the context of reproductive biology and assisted reproductive technologies (ARTs).

Down Syndrome (DS) is a genetic disorder caused by the presence of an extra copy of chromosome 21, and leading to various developmental and cognitive defects. A critical feature of DS is the occurrence of oxidative distress particularly in the brain, which exacerbates neurodevelopmental processes. Mitochondria play a crucial role in cell energy metabolism and their impairment is one of the major causes of oxidative distress in several pathologies. Hence, this study investigates mitochondrial proteostasis by the mean of the mitochondrial Unfolded Protein Response (UPRmt) and the mitochondrial protein quality control (MQC) mechanisms in the context of DS, focusing on their implications in redox homeostasis in brain development. We analyzed key UPRmt markers and mitochondrial function in the frontal cortex isolated fromTs2Cje mice, a model for DS, across different developmental stages. Our results demonstrate significant alterations in UPRmt markers, particularly at postnatal day 0 (P0) and 1 month (1M). These changes indicate early UPRmt activation, primarily driven by the ATF5/GRP75 axis, although compromised by reduced levels of other components. Impaired UPRmt correlates with decreased mitochondrial activity, evidenced by reduced oxygen consumption rates and altered expression of OXPHOS complexes. Additionally, elevated oxidative stress markers such as 3-nitrotyrosine (3-NT), 4-hydroxynonenal (HNE), and protein carbonyls (PC) were observed, linking mitochondrial dysfunction to increased oxidative damage. Defects of MQC, including disrupted biogenesis, increased fission, and the activation of mitophagy were evident mostly at P0 and 1M consistent with UPRmt activation. Principal Component Analysis revealed distinct phenotypic differences between Ts2Cje and control mice, driven by these molecular alterations. Our findings underscore the critical role of UPRmt and MQC in DS brain development, highlighting potential therapeutic targets to mitigate mitochondrial dysfunction and oxidative distress, thereby alleviating some of the neurodevelopmental and cognitive impairments associated with DS.

Acute lung injury (ALI) is a devastating clinical syndrome without effective therapy. Celastrol, as a natural anti-inflammatory compound, has showed therapeutic potential against inflammatory diseases. In this study, we have investigated the potential effect of Celastrol on lipopolysaccharide (LPS)-induced ALI. C57BL/6J mice, Nrf1-knockout mice and A549 (human alveolar epithelial cell line) cells were used to investigate the protective role of Celastrol in LPS-induced ALI. Our data showed that administration of Celastrol significantly alleviated lung pathologic injury and increased the survival rate, which was associated with the improvement of mitochondrial function in the injured lung. Moreover, Celastrol enhanced phosphorylation of AMP-activated protein kinase (AMPK) and expression of peroxisome proliferator-activated receptor coactivator protein-1α (PGC-1α), thereby increasing the nuclear translocation of nuclear respiratory factor 1 (Nrf1) and subsequent up-regulation of its downstream mitochondria electron transport chain complex I (NDUF) gene expression, which induced an increase in mitochondrial complex Ⅰ activity. The beneficial effects of Celastrol on regulation of Nrf1 were abolished by inhibition of AMPK and PGC-1α. Finally, in Nrf1 deficient mice, the protective effects of Celastrol on LPS-induced ALI were largely vanished. Our data indicated that Celastrol can prevent LPS-induced ALI by improving mitochondrial function through AMPK/PGC-1α/Nrf1-dependent mechanism, suggesting that Celastrol may represent a novel therapeutic potential for LPS-induced ALI.

The NLRP3 inflammasome plays a pivotal role in the progression of inflammatory diseases. Mitochondrial damage, oxidative stress and mitochondrial DNA (mtDNA) leak are the key upstream factors for NLRP3 inflammasome activation. Nepetin (Nep), a naturally occurring flavonoid found with anti-inflammatory properties; however, whether it can affect the NLRP3 inflammasome activation and its precise anti-inflammatory mechanism remains unclear. In this study, we demonstrated that Nep enhances PINK1-mediated ubiquitin phosphorylation, which promotes mitophagy and subsequently inhibits NLRP3 inflammasome activation and pyroptosis in macrophages. The administration of Nep to macrophages alleviated of mitochondrial damage, reduced mitochondrial superoxide production, restored mitochondrial membrane potential and prevented the mtDNA leakage. These findings provide compelling evidence for the antioxidant effect of Nep. Furthermore, the pivotal function of mitophagy in the NLRP3 inflammasome inhibitory impact of Nep was substantiated through the utilisation of mitophagy inhibitors and siRNA techniques. Notably, Nep increased survival and reduced organ damage in mice with systemic inflammation by inhibiting NLRP3 inflammasome activation. In addition, Nep suppressed NLRP3 inflammasome activation in obese mice, which led to reduced white adipose and liver inflammation, thereby ameliorating insulin resistance. In conclusion, our findings suggest that Nep is a potent NLRP3 inflammasome inhibitor and a promising candidate for the development of anti-inflammatory therapies.

Hypertension is a major global health issue, contributing to significant cardiovascular morbidity and mortality. Mitochondrial dysfunction, particularly through dysregulated mitophagy, has been implicated in the pathogenesis of hypertension. We wanted to find out the relationship between mitochondrial autophagy and changes in arterial smooth muscle cell tension and the molecular mechanism. Using RNA-seq analysis, we identified significant upregulation of autophagy-related genes, including Pink1, in the aortas of spontaneously hypertensive rats (SHR) compared to normotensive Wistar-Kyoto (WKY) rats. Further in vivo and in vitro studies revealed enhanced mitophagy, characterized by increased expression of Pink1 protein. Our experiments showed that knockdown of Pink1 expression by shRNA attenuated KPSS-induced vascular smooth muscle cells (VSMCs) contraction, suggesting that excessive mitophagy contributes to vascular dysfunction in hypertension. These findings highlight Pink1-mediated mitophagy as a crucial player in hypertensive vascular remodeling and present a potential therapeutic target for managing hypertension.

The RNA chaperone Hfq plays a pivotal role in many bacteria, acting as a regulator of gene expression and promoting interaction between mRNA-sRNA pairs in Gram-negative bacteria. However, in Gram-positive bacteria this protein is expendable for riboregulation, and the main function of Hfq remains elusive. This work unveils a novel function for Hfq in the oxidative stress response of the human pathogen Listeria monocytogenes, a Gram-positive bacterium responsible for the infectious disease listeriosis. Disruption of hfq gene (Δhfq) results in a hypersensitive phenotype towards hydrogen peroxide (H₂O₂), in which sub-inhibitory concentrations of this reactive oxygen species (ROS) severely impair growth and viability of L. monocytogenes EGD-e. A Δhfq-complemented strain does not show this phenotype. This Hfq-dependent regulation of oxidative stress seems specific for H₂O₂, as exposure to superoxides caused no differences. We demonstrate that Hfq has a dual regulatory role in the expression of catalase (kat), the key enzyme involved in H₂O₂ detoxification. Hfq influences kat transcription under non-stress conditions by modulating the levels of the transcriptional repressor PerR, and also acts post-transcriptionally by stabilizing kat mRNA under H₂O₂-induced stress. Indeed, enzymatic assays revealed reduced catalase activity in Δhfq cell extracts, a result unrelated to differences in cellular iron content. Bacterial infection triggers immune cells to produce massive amounts of ROS, like H₂O₂. We show that inactivation of Hfq increases susceptibility to macrophage killing, connecting Hfq with the stress resistance and virulence of L. monocytogenes EGD-e. Overall, these findings advance the understanding of Hfq function within Gram-positive bacteria, revealing for the first time that Hfq is a novel regulator of catalase expression. This paves the way for the study of yet unknown oxidative stress response pathways regulated by Hfq in other pathogens.

Modulating the equilibrium between glucose metabolism and fatty acid metabolism represents highly promising novel strategies for therapy of myocardial ischemia/reperfusion (I/R) injury. Sphingosylphosphorylcholine (SPC), an intermediate metabolite of sphingolipids, has shown cardioprotective roles during myocardial infarction by regulating the activities of various transcript factors. Gene microarray revealed that SPC significantly upregulated the expression of GATA zinc finger domain protein 1 (GATAD1), which is a vital transcript factor affecting heart development and various heart diseases. However, it remains unclear whether SPC is involved in the regulation of cardiac fatty acid and glucose metabolism via GATAD1. In this study, we found that myocardium-specific Gatad1 knockout (Gatad1 CKO) significantly increased the myocardial infarct size, impaired cardiac function in I/R mice, and disrupted the protective effect of SPC on the hearts of I/R mice. Immunofluorescence experiment and Western blot evaluation of the nuclear-cytoplasmic fractionation sample showed that GATAD1 acted as a transcription factor and was regulated by SPC. Double fluorescence reporting experiment and quantitative polymerase chain reaction (qPCR) revealed that GATAD1 could inhibit the expression of genes involved in fatty acid oxidation (FAO), i.e., acetyl-coenzyme A acyltransferase 2 (Acaa2) and medium-chain acyl-CoA dehydrogenase (Acadm), and promoted the expression of genes involved in glucose oxidation, i.e., pyruvate dehydrogenase E1 α subunit (Pdha1). Small interfering RNA (SiRNA) or overexpression strategies confirmed the pro-apoptotic roles of Acaa2 and Acadm and anti-apoptotic role of Pdha1 in cardiac myocytes challenged with I/R treatment. In summary, our findings suggest that SPC can be used as a candidate to prevent I/R injury by reshaping fatty acid and glucose metabolism. Transcription factor GATAD1 plays a crucial role in regulating fatty acid oxidation and glucose oxidation homeostasis and is involved in SPC-mediated cardioprotection during I/R of the heart. Our study identifies GATAD1 as a new therapeutic target for clinical treatment of myocardial I/R injury.

Sulfoxide synthase OvoA is the key enzyme involved in the biosynthesis of ovothiols (OSHs), secondary metabolites endowed with unique antioxidant properties. Understanding the evolution of such enzymes and the diversity of their metabolites should reveal fundamental mechanisms governing redox signaling and environmental adaptation. "Early-branching" animals such as Cnidaria display unique molecular diversity and symbiotic relationships responsible for the biosynthesis of natural products, however, they have been neglected in previous research on antioxidants and OSHs. In this work, we have integrated genome and transcriptome mining with biochemical analyses to study the evolution and diversification of OSHs biosynthesis in cnidarians. By tracing the history of the ovoA gene, we inferred its loss in the latest common ancestor of Medusozoa, followed by the acquisition of a unique ovoB/ovoA chimaeric gene in Hydrozoa, likely through a horizontal gene transfer from dinoflagellate donors. While Anthozoa (corals and anemones), bearing canonical ovoA genes, produced a striking variety of OSHs (A, B, and C), the multifunctional enzyme in Hydrozoa was related to OSH B biosynthesis, as shown in Clytia hemisphaerica. Surprisingly, the ovoA-lacking jellyfish Aurelia aurita and Pelagia noctiluca also displayed OSHs, and we provided evidence of their incorporation from external sources. Finally, transcriptome mining revealed ovoA conserved expression pattern during larval development from Cnidaria to more evolved organisms and its regulation by external stimuli, such as UV exposure. The results of our study shed light on the origin and diversification of OSH biosynthesis in basal animals and highlight the importance of redox-active molecules from ancient metazoans as cnidarians to vertebrates.

Peroxiredoxin (PRDX) primarily employs electrons from thioredoxin in order to reduce peroxides. PRDX4 mainly resides either in the endoplasmic reticulum (ER) lumen or in extracellular spaces. Due to the usage of alternative promoters, a first exon is transcribed from different regions of the Prdx4 gene, which results in two types of mRNAs. The first type is designated as Prdx4. It is translated with a cleavable, hydrophobic signal sequence and is expressed in most cells throughout the body. The second type is designated as Prdx4t. The peroxidase activity of PRDX4 is involved in both the reduction of hydrogen peroxides and in the oxidative folding of nascent proteins in the ER. Prdx4 appears to have evolved from an ancestral gene in Eutherians simultaneously with the evolution of sperm protamine to cysteine-rich peptides, and, therefore, the testis-specific PRDX4t is likely involved in spermatogenesis through the oxidative folding of protamine. The dysfunction of PRDX4 leads to oxidative damage and ER stress, and is related to various diseases including diabetes and cancer. In this review article we refer to the results of biological and medical research in order to unveil the functional consequences of this unique member of the PRDX family.