Antioxidants & redox signaling最新文献

Aims: Peroxiredoxins (Prx) are ubiquitous Cys peroxidases regulated by sulfinylation, a modification that occurs when the sulfenic acid generated on the catalytic Cys by peroxide reduction reacts with a second molecule of peroxide. In the Prx1 family, sulfinylation sensitivity is controlled by competition between a structural transition from a fully folded (FF) to locally unfolded (LU) conformation and the chemical step of sulfinylation. The initial peroxide reduction relies on a conserved catalytic hydroxylated residue that allows peroxide optimal activation. This study aimed at investigating the role of this catalytic residue in sulfinylation. Results: Sulfenate attack on peroxide was favored by one order of magnitude when a catalytic Thr was present, for yeast cytosolic Prx1-type enzymes, human Prx1 and yeast mitochondrial Prx, a Prx6-type enzyme. Furthermore, pKa determination supported the notion of electrostatic interaction between the catalytic hydroxyl and sulfenate intermediate. Finally, FF-LU transition kinetics was faster with a catalytic Thr, supporting that the hydroxyl group proximity to the nascent sulfenate group also promotes the FF-LU transition. Innovation: We identify a major mechanism that activates sulfinylation in hyperoxidation-sensitive Prxs from the Prx1 and Prx6 families. Furthermore, we show that the catalytic hydroxylated residue holds a dual role in regulating hyperoxidation sensitivity, by activating the sulfinylation reaction, while also promoting the competing FF to LU transition, thus acting as an important regulatory determinant. Conclusion: The present work sets the basis for investigating other instances of Cys proteins regulated by sulfinylation, a modification increasingly recognized in cell redox regulation and signaling. Antioxid. Redox Signal. 43, 1-13.

Aims: Duchenne muscular dystrophy (DMD) is a severe, incurable X-linked genetic disorder caused by mutations in the DMD gene, leading to a deficiency of the muscle structural protein, dystrophin, which results in damage to skeletal and cardiac muscles. Altered expression of enzymes that generate hydrogen sulfide (H₂S) has been demonstrated in dystrophic muscles, however, the exact role of this gasotransmitter in DMD remains elusive. Here, we investigated the effect of the slow-releasing H₂S donor (GYY4137) on the skeletal muscles of the dystrophin-deficient mdx mice. Methods and Results: Grip strength assay and the treadmill exhaustion test showed that administering the GYY4137 donor to mdx mice improved DMD-related decline in motor functions. Additionally, the H₂S donor decreased the level of muscle damage markers such as lactate dehydrogenase, creatine kinase, and osteopontin (OPN). Histological, gene, and protein analyses of the dystrophic gastrocnemius and diaphragm muscles revealed reduced inflammation and fibrosis after treatment with the H₂S donor. Moreover, we showed decreased necrosis with improved muscle regeneration and angiogenesis. We demonstrated that GYY4137 upregulates the levels of phosphorylated AMPKα, as well as the cytoprotective and antioxidant heme oxygenase-1, mitochondrial superoxide dismutase, and glutamate-cysteine ligase modifier subunit (Gclm). Finally, it exerted an anti-apoptotic effect by reducing cleaved caspase-3 and caspase-3 and increasing AKT phosphorylation. Innovation and Conclusion: The administration of GYY4137 improves exercise capacity and ameliorates the markers of inflammation, fibrosis, oxidative stress, apoptosis, and necrosis in the skeletal muscles of mdx animals pointing out its possible therapeutic use in DMD pathology. Antioxid. Redox Signal. 43, 115-137.

Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent hepatic disorder worldwide. Arachidonic acid 15-lipoxygenase (ALOX15), an enzyme catalyzing the peroxidation of polyunsaturated fatty acids, plays a crucial role in various diseases. Here, we sought to investigate the involvement of ALOX15 in MASLD. Results: In this study, we observed upregulation of ALOX15 in the liver of high-fat diet (HFD)- and streptozotocin (STZ)-induced mice. Metabolomic analysis revealed elevated levels of ALOX15 metabolites, 12(S)-hydroperoxyeicosatetraenoic acid and 15(S)-hydroperoxyeicosatetraenoic acid. Transcriptomic analysis showed that the increased fatty acid uptake regulated by the PPARγ/CD36 pathway predominated in lipid accumulation. To elucidate the mechanism underlying ALOX15-induced lipid accumulation, HepG2 cells were transfected with a lentivirus expressing ALOX15 or small interfering RNA targeting ALOX15 and exposed to palmitic acid (PA). Both ALOX15 overexpression and PA exposure led to increased intracellular free fatty acid and triglyceride, resulting in lipotoxicity. ALOX15 overexpression aggravated the effect of PA, while the knockdown of ALOX15 attenuated PA-induced lipotoxicity. Moreover, the treatment with PPARγ antagonist GW9662 or CD36 inhibitor sulfosuccinimidyl oleate sodium effectively reduced lipid accumulation and lipotoxicity resulting from ALOX15 overexpression and PA exposure, indicating the involvement of the PPARγ/CD36 pathway in ALOX15-mediated lipid accumulation. Furthermore, liraglutide, a widely used glucagon-like peptide 1 receptor (GLP-1R) agonist (GLP-1RA), improved hepatic lipid accumulation in HFD/STZ-induced mice by suppressing the ALOX15/PPARγ/CD36 pathway. Innovation and Conclusion: Our study underscores the potential of ALOX15 as an emerging therapeutic target for MASLD. In addition, the GLP-1RA may confer hepatoprotection by regulating ALOX15, enhancing our comprehension of the mechanisms underpinning their protection on MASLD. Antioxid. Redox Signal. 43, 37-55.

Significance: The role of melatonin (MEL) in plants has gained significant relevance due to its involvement in a wide range of physiological functions, particularly in response mechanisms to both abiotic and biotic stresses. Recent Advances: Recent progress highlights the significance of the biosynthetic pathway of MEL in plants, which surpasses that of animals. The discovery of specific plant MEL receptors has revealed new signaling mechanisms. Studies also show that applying exogenous MEL offers benefits under stress conditions and helps maintain the organoleptic qualities of fruits and vegetables during postharvest storage. Critical Issues: This review explores MEL's biochemistry, emphasizing its dual role as both an antioxidant and a signaling molecule. It examines how MEL interacts with phytohormones, its role in regulating the metabolism of reactive oxygen and nitrogen species, and its influence on plant growth and stress tolerance. The potential of MEL-based biotechnological applications for enhancing crop resilience and postharvest quality is also discussed. Future Directions: Future research should prioritize molecular mechanisms, high-throughput approaches, and translational studies to bridge the gap between fundamental science and agricultural practices. MEL's role as a sustainable solution in agriculture offers exciting possibilities for addressing global food security challenges. Antioxid. Redox Signal. 43, 151-188.

Aims: BTB and CNC homology 1 (Bach1) is a transcription factor that mediates oxidative stress and inflammation and participates in the progression of diseases such as atherosclerosis, colitis, and acute lung injury. In this study, we aimed to explore the role of Bach1 in radiation pneumonitis (RP) and elucidate its underlying mechanism. Results: Bach1 expression was significantly elevated in the lung tissues of RP mice. Deletion of the Bach1 gene markedly ameliorated X-ray-induced RP by reducing inflammation and oxidative stress. In vitro experiments demonstrated that Bach1 deficiency mitigated radiation-induced oxidative damage and inflammation in bone marrow-derived macrophages. Conversely, Bach1 overexpression exacerbated oxidative stress and inflammation in radiation-treated macrophages. Mechanistically, using the JASPAR database, electromobility shift assays, and luciferase reporter assays, we revealed that Bach1 inhibited mRNA expression of mitochondrial transcription factor A (TFAM) by directly binding to its promoter region. Innovation and Conclusion: Our findings indicate that silencing of Bach1 protects against RP by upregulating the mRNA expression of TFAM, which, in turn, enhances mitochondrial function and reduces inflammation and oxidative stress. This study provides valuable insights into potential therapeutic strategies for patients with RP through Bach1 inhibition. Antioxid. Redox Signal. 43, 75-91.

Aims: Myocardial fibrosis is an important medium for atrial fibrillation (AF). Exosomes have been demonstrated to affect the development of AF. This study explored the molecular mechanism of exosomes from patients with AF (AF-exo) mediating myocardial fibrosis and thus affecting the development of AF. Results: Prolactin-induced protein (PIP) is highly expressed in AF-exo. AF-exo promoted the proliferation and activation of cardiac fibroblasts (CFs) as well as the migration and endothelial-to-mesenchymal transition (EndMT) of human umbilical vein endothelial cells (HUVECs). However, the effect of AF-exo on CFs and HUVECs was mitigated by PIP-specific short hairpin RNA (shPIP). Adeno-associated virus (AAV)-shPIP reduced the incidence and duration of AF in rats, and improved myocardial fibrosis and collagen deposition. ATPase plasma membrane Ca²⁺ transporting 2 (ATP2B2) overexpression or inhibition reverses the role of PIP or shPIP in CFs, HUVECs, and AF rats. Activation of the cyclic guanosine monophosphate/protein kinase G (cGMP/PKG) pathway is beneficial to alleviate myocardial fibrosis, but this effect is mitigated by shATP2B2. Innovation: Our investigation substantiates the pivotal role of the PIP/ATP2B2 axis in both HUVEC myocardial fibrosis and EndMT progression. Our findings suggest that AF-exo can suppress the activation of the cGMP/PKG pathway mediated by ATP2B2 through exosomal PIP, thus promoting myocardial fibrosis, indicating potential targets for novel antifibrotic drug development targeting either PIP or ATP2B2. Conclusion: Exosomal PIP can inhibit the activation of cGMP/PKG pathway mediated by ATP2B2, thus promoting the development of AF. Antioxid. Redox Signal. 43, 14-36.

Aims: Dopamine agonists (DAs) are the first-line treatment for patients with prolactin-secreting pituitary adenoma (PRL adenoma). However, a subset of individuals exhibits poor responses, known as DA resistance. Previous studies have reported that DA resistance is more prevalent in male patients. This study aims to investigate the relationship between androgen receptor (AR) expression and DA resistance, as well as to explore underlying mechanisms of AR-mediated DA resistance. Results: Our results demonstrated that patients with higher AR expression exhibit greater resistance to DA in our cohort of DA-resistant PRL adenoma. Furthermore, AR was found to be involved in cell proliferation, PRL secretion, and resistance to bromocriptine (BRC) both in vitro and in vivo. Mechanistically, we demonstrated that intracellular reactive oxygen species (ROS) function as upstream mediators of apoptosis and ferroptosis following BRC treatment. As a ligand-dependent transcription factor, AR could translocate to the nucleus and transcriptionally promote NFE2-like bZIP transcription factor 2 (NRF2) expression, which regulates intracellular ROS levels, thereby enhancing cell viability and conferring DA resistance to pituitary adenoma (PA) cells. Finally, AR targeting agents were used to inhibit AR signaling, downregulate NRF2 transcription, and sensitize PA cells to BRC treatment. Conclusion and Innovation: We demonstrated that AR plays a crucial role in mediating DA resistance in PRL adenoma. Mechanistically, AR promotes cell proliferation and PRL secretion and confers drug resistance by transcriptionally regulating NRF2 expression to maintain redox homeostasis in PA cells. Finally, combining AR targeting agents with BRC shows promise as a therapeutic strategy for treating PRL adenomas. Antioxid. Redox Signal. 42, 954-972.

Aims: Diabetic nephropathy (DN) is a major cause of end-stage renal disease, with no therapeutic interventions available to control its progression. Ferroptosis, an iron-dependent regulated cell death characterized by lipid peroxidation, plays a pivotal role in the pathogenesis of DN. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an effective treatment modality for DN; however, the underlying mechanism of action remains unclear. The aim of the present study was to investigate whether hUCMSCs alleviate DN via inhibiting ferroptosis and its molecular mechanisms in type 2 diabetic mice and high-glucose and palmitate-stimulated human renal tubular epithelial cell (HK-11) models. Results: Our findings revealed that hUCMSCs improved the renal structure and function and tubular injuries. HUCMSC treatment can inhibit ferroptosis by decreasing iron content, reducing reactive oxygen species, malondialdehyde and 4-hydroxynonenal generation, decreasing the expression of positive ferroptosis mediator transferrin receptor 1 and long-chain acyl-CoA synthetase 4, and enhancing the expression of negative ferroptosis mediators (i.e., ferritin heavy chain, glutathione peroxidase 4, and system Xc-cystine/glutamate reverse transporter). Mechanistically, hUCMSC treatment inhibited c-Jun N-terminal kinase (JNK) and Kelch-like ECH-associated protein 1 (KEAP1) activation while increasing the expression of nuclear factor erythroid 2-related factor 2 (NRF2). Furthermore, pretreatment of HK-11 cells with NRF2 siRNA, the JNK inhibitor SP600125, or the JNK agonist anisomycin demonstrated the regulation of the JNK/KEAP1/NRF2 signaling pathway by hUCMSCs. Innovation and Conclusion: HUCMSCs inhibit ferroptosis in DN via the JNK/KEAP1/NRF2 signaling pathway, providing a new perspective and scientific evidence for treating DN. Antioxid. Redox Signal. 42, 807-826.

Significance: In all modern urbanized and industrialized societies, noncommunicable diseases, such as cardiovascular disease (CVD), are becoming a more important cause of morbidity and mortality. Classical risk factors for CVDs, such as hypertension, are reinforced by behavioral risk factors, e.g., smoking and diet, and environmental risk factors, e.g., transportation noise and air pollution. Recent Advances: Both transportation noise and air pollution have individually been shown to increase the risk for CVD in large cohorts. Insights from animal studies have revealed pathophysiologic mechanisms by which these stressors influence the cardiovascular system. Noise primarily causes annoyance and sleep disturbance, promoting the release of stress hormones. Air pollution primarily damages the lung, where it causes local inflammation and an increase in oxidative stress, which can propagate to the circulation and remote organs. Critical Issues: Both noise and air pollution converge at the vascular level, where the inflammatory state and oxidative stress cause dysfunction in vascular signaling and promote atherosclerotic plaque formation and thrombosis. Both inflammation and oxidative stress are key aspects of traditional cardiovascular risk factors, such as arterial hypertension. The similarities among the mechanisms of environmental risk factor-induced CVD and hypertension indicate that a complex interplay between them can drive the onset and progression of CVDs, leading to synergistic health impacts. Future Directions: Our present overview of the negative effects of noise and air pollution on the cardiovascular system provides a mechanistic link to the traditional CVD risk factor, hypertension, which could be used to protect patients with preexisting CVD better. Antioxid. Redox Signal. 42, 827-847.

Significance: Growing evidence indicates the importance of redox reactions homeostasis, mediated predominantly by reactive oxygen species (ROS) in influencing the development, differentiation, progression, metastasis, programmed cell death, tumor microenvironment, and therapeutic resistance of cancer. Therefore, reviewing the ROS-linked epigenetic changes in cancer is fundamental to understanding the progression and prevention of cancer. Recent Advances: We review in depth the molecular mechanisms involved in ROS-mediated epigenetic changes that lead to alteration of gene expression by altering DNA, modifying histones, and remodeling chromatin and noncoding RNA. Critical Issues: In cancerous cells, alterations of the gene-expression regulatory elements could be generated by the virtue of imbalance in tumor microenvironment. Various oxidizing agents and mitochondrial electron transport chain are the major pathways that generate ROS. ROS plays a key role in carcinogenesis by activating pro-inflammatory signaling pathways and DNA damage. This loss of ROS-mediated epigenetic regulation of the signaling pathways may promote tumorigenesis. We address all such aspects in this review. Future Directions: Developments in this growing field of epigenetics are expected to contribute to further our understanding of human health and diseases such as cancer and to test the clinical applications of redox-based therapy. Recent studies of the cancer-epigenetic landscape have revealed pervasive deregulation of the epigenetic factors in cancer. Thus, the study of interaction between ROS and epigenetic factors in cancer holds a great promise in the development of effective and targeted treatment modalities. Antioxid. Redox Signal. 42, 848-867.