Actin cytoskeleton and plasma membrane aquaporins are involved in different drought response of Arabidopsis rhd2 and der1 root hair mutants.

Actin cytoskeleton and reactive oxygen species are principal determinants of root hair polarity and tip growth. Loss of function in RESPIRATORY BURST OXIDASE HOMOLOG C/ROOT HAIR DEFECTIVE 2 (AtRBOHC/RHD2), an NADPH oxidase emitting superoxide to the apoplast, and in ACTIN 2, a vegetative actin isovariant, in rhd2-1 and der1-3 mutants, respectively, lead to similar defects in root hair formation and elongation Since early endosome-mediated polar localization of AtRBOHC/RHD2 depends on actin cytoskeleton, comparing the proteome-wide consequences of both mutations might be of eminent interest. Therefore, we employed a differential proteomic analysis of Arabidopsis rhd2-1 and der1-3 mutants. Both mutants exhibited substantial alterations in abundances of stress-related proteins. Notably, plasma membrane (PM)-localized PIP aquaporins showed contrasting abundance patterns in the mutants compared to wild-types. Drought-responsive proteins were mostly downregulated in rhd2-1 but upregulated in der1-3. Proteomic data suggest that opposite to der1-3, altered vesicular transport in rhd2-1 mutant likely contributes to the deregulation of PM-localized proteins, including PIPs. Moreover, lattice light sheet microscopy revealed reduced actin dynamics in rhd2-1 roots, a finding contrasting with previous reports on der1-3 mutant. Phenotypic experiments demonstrated a drought stress susceptibility in rhd2-1 and resistance in der1-3. Thus, mutations in AtRBOHC/RHD2 and ACTIN2 cause similar root hair defects, but they differently affect the actin cytoskeleton and vesicular transport. Reduced actin dynamics in rhd2-1 mutant is accompanied by alteration of vesicular transport proteins abundance, likely leading to altered protein delivery to PM, including aquaporins, thereby significantly affecting drought stress responses.

NADPH-cytochrome P450 reductase involved in the lambda-cyhalothrin susceptibility on the green mirid bug Apolygus lucorum.

NADPH-cytochrome P450 reductase (CPR) is crucial for the detoxification process catalysed by cytochrome P450, which targets various exogenous xenobiotics, as well as pesticides. In our research, we successfully obtained the complete cDNA sequence of Apolygus lucorum's CPR (AlCPR) using reverse transcription PCR along with rapid amplification of cDNA ends technology. Bioinformatics analysis exhibited that the inferred amino acid sequence of AlCPR is characteristic of standard CPRs, featuring an N-terminal membrane anchor and three conserved FMN, FAD and NADP binding sites. Phylogenetic result revealed that AlCPR was positioned within the Hemiptera cluster, showing a close evolutionary relationship with the CPR of Cimex lectularius. The real-time quantitative PCR results demonstrated widespread expression of AlCPR across various life stages and tissues of A. lucorum, with the most prominent expression in adults and the abdominal region. Injecting double-stranded RNA of AlCPR only significantly increased the lambda-cyhalothrin susceptibility in lambda-cyhalothrin-resistant strain rather than the susceptible strain. These findings suggest a potential link between AlCPR and the P450-dependent defence mechanism against lambda-cyhalothrin in A. lucorum.

Structural insights into the mechanism underlying the dual cofactor specificity of glyoxylate reductase from Acetobacter aceti in the ß-hydroxyacid dehydrogenase family.

The ß-hydroxyacid dehydrogenase family exhibits diverse cofactor preferences: some enzymes favor NAD, others favor NADP, and a subset can utilize both NAD and NADPH. Glyoxylate reductase from Acetobacter aceti JCM 20276 (AacGR) exhibits a dual cofactor specificity for NADPH and NADH in its catalytic reduction of glyoxylate to glycolate. In contrast to conventional cofactor-discriminating motifs, NRX and DXX, found in NADP- and NAD-specific enzymes, respectively, AacGR has a TPS motif in the equivalent position. Here we report X-ray crystallographic analysis of AacGR in its ligand-free form, and in complexes with NADPH and NADH, revealing critical interactions: Ser41 of the TPS motif interacted with the 2'-phosphate group of NADPH, while no analogous interaction occurred with the ribose hydroxy groups of NADH. Moreover, the TPS motif resided within a characteristic ß-turn-like structure adjacent to a long flexible loop. Site-directed mutagenesis and kinetic analyses suggest that Ser41 facilitates NADPH binding, while the lack of a direct interaction of the TPS motif with NADH may allow for NADH utilization. The conformational dynamics of the TPS-containing ß-turn-like structure along with the flexible loop likely govern the dual cofactor specificity and catalytic turnover of AacGR.

Exploring fermentative metabolic response to varying exogenous supplies of redox cofactor precursors in selected wine yeast species.

The use of non-Saccharomyces yeasts in winemaking is gaining traction due to their specific phenotypes of technological interest, including their unique profile of central carbon metabolites and volatile compounds. However, the lack of knowledge about their physiology hinders their industrial exploitation. The intracellular redox status, involving NAD/NADH and NADP/NADPH cofactors, is a key driver of yeast activity during fermentation, notably directing the formation of metabolites that contribute to the wine bouquet. The biosynthesis of these cofactors can be modulated by the availability of their precursors, nicotinic acid and tryptophan, and their ratio by that of thiamine. In this study, a multifactorial experiment was designed to assess the effects of these three nutrients and their interactions on the metabolic response of various wine yeast species. The data indicated that limiting concentrations of nicotinic acid led to a species-dependent decrease in intracellular NAD(H) concentrations, resulting in variations of fermentation performance and production of metabolic sinks. Thiamine limitation did not directly affect redox cofactor concentrations or balance, but influenced redox management and subsequently the production of metabolites. Overall, this study identified nicotinic acid and thiamine as key factors to consider for species-specific modulation of the metabolic footprint of wine yeasts.

Multifaceted roles of NADPH oxidases in the growth and pathogenicity of Beauveria bassiana.

Reactive oxygen species (ROS), synthesized by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) complex, are vital molecules in biological cells, influencing various physiological processes such as fungal growth, development, and virulence. Beauveria bassiana, an entomopathogenic fungus, is a promising biopesticide for agricultural, forestry, and urban pest control. This study focuses on the characterization of NADPH oxidases (Noxs) in B. bassiana. Gene expression profiles of Noxs in B. bassiana (BbNoxs) were analysed using RT-qPCR. Knockout strains of single BbNoxA, BbNoxB, BbNoxR, and double BbNoxA and BbNoxB were constructed via homologous recombination, and their phenotypic characteristics were examined. Fungal virulence was evaluated using Galleria mellonella larvae, and infection structures formation and penetration ability were assessed on cicada wings. ROS production and actin assembly during fungal growth and infection were detected using staining and marker methods. Expression analysis revealed significant upregulation of BbNoxs during fungal growth and infection. Compared to the wild-type strain, single knockouts (ΔBbNoxA/B/R) and double knockout (ΔBbNoxAB) of BbNoxs exhibited reduced conidial yields, accelerated conidial germination rates. Deletion of BbNoxB or BbNoxR decreased fungal virulence compared to the WT strain in topical inoculation experiments. Additionally, loss of BbNoxB or BbNoxR impaired infection structures formation, penetration ability, ROS production, and actin aggregation during fungal infection. BbNoxs are crucial for fungal growth, development, and virulence in B. bassiana, playing essential roles in infection structures formation, penetration, ROS production, and actin assembly. Understanding their functions provides insights into B. bassiana's pathogenic mechanisms.

Mandatory role of endoplasmic reticulum in preserving NADPH regeneration in starved MDA-MB-231 breast cancer cells.

Cancer growth requires high amount of nicotinamide adenine dinucleotide phosphate (NADPH) to feed the anabolic reactions and preserve the redox balance. NADPH level is largely preserved by the oxidative arm of the pentose phosphate pathway (PPP). Here, we show that prolonged glucose deprivation of triple negative breast cancer MDA-MB-231 cells decreases proliferation rate, promotes hexose funneling to glycolysis hampering the PPP. The impairment in PPP activity and the consequent NADPH depletion are partially counterbalanced by enhancing the malic enzyme-1 catalyzed conversion of glutamine-derived malate to pyruvate. However, the use of these glucose-independent carbons implies the integrity of the two PPPs represented in all eukaryotic cells, i.e., the well-recognized cytosolic PPP, triggered by glucose-6-phosphate dehydrogenase (G6PD) and its reticular counterpart, triggered by hexose-6P-dehydrogenase (H6PD). This evidence configures the reticular PPP as a mandatory player in the regeneration of NADPH reductive power by cancer cells.

Endothelial ENaC-α Restrains Oxidative Stress in Lung Capillaries in Murine Pneumococcal Pneumonia-associated Acute Lung Injury.

Infection of lung endothelial cells with pneumococci activates the superoxide-generating enzyme NADPH oxidase 2 (NOX2), involving the pneumococcal virulence factor pneumolysin (PLY). Excessive NOX2 activity disturbs capillary barriers, but its global inhibition can impair bactericidal phagocyte activity during pneumococcal pneumonia. Depletion of the α subunit of the epithelial sodium channel (ENaC) in pulmonary endothelial cells increases expression and PMA-induced activity of NOX2. Direct ENaC activation by TIP peptide improves capillary barrier function -measured by electrical cell substrate impedance sensing in endothelial monolayers and by Evans Blue Dye incorporation in mouse lungs- following infection with pneumococci. PLY-induced hyperpermeability in HL-MVEC monolayers is abrogated by both NOX2 inhibitor gp91dstat and TIP peptide. Endothelial NOX2 expression is assessed by increased surface membrane presence of phosphorylated p47phox subunit (Western blotting) in vitro and by co-localization of CD31 and gp91phox in mouse lung slices using DuoLink, whereas NOX2-generated superoxide is measured by chemiluminescence. TIP peptide blunts PMA-induced NOX2 activity in cells expressing ENaC-α, but not in neutrophils, which lack ENaC. Conditional endothelial ENaC-α KO (enENaC-α KO) mice develop increased capillary leak upon i.t. instillation with PLY or pneumococci, compared to wild type (wt) animals. TIP peptide diminishes capillary leak in Sp-infected wt mice, without significantly increasing lung bacterial load. Lung slices from Sp-infected enENaC-α KO mice have a significantly increased endothelial NOX2 expression, as compared to infected CRE mice. In conclusion, endothelial ENaC may represent a novel therapeutic target to reduce NOX2-mediated oxidative stress and capillary leak in ARDS, without impairing host defense.

Deciphering the mechanisms underlying the neuroprotective potential of kaempferol: a comprehensive investigation.

Neurodegenerative disorders are characterized by neuronal degradation, dysfunction, or death within the CNS. Oxidative and inflammatory stress play crucial roles in the pathogenesis of various neurodegenerative diseases. The interplay between these stressors and dysregulated cellular signaling pathways contributes to neurodegeneration. Downregulation of NRF-2 compromises antioxidant defense, exacerbating neuronal damage, while increased TLR-4/MAPK and TLR-4/NF-κB signaling promotes neuroinflammation. Excessive ROS production by NADPH oxidase leads to oxidative damage and neuronal apoptosis. The strategies targeting NRF-2, TLR-4-mediated inflammatory stress, and NADPH oxidase activity promise to mitigate neuronal damage and halt the progression of the disease. Kaempferol is a flavonoid polyphenol antioxidant found abundantly in various fruits and vegetables, including apples, grapes, tomatoes, and broccoli. It is widely found in medicinal plants including Equisetum spp., Sophora japonica, Ginkgo biloba, and Euphorbia pekinensis (Rupr.). A substantial body of in vitro and in vivo evidences have demonstrated the neuroprotective potential of kaempferol against neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Kaempferol demonstrates multifaceted potential in mitigating neuroinflammation, apoptosis, and oxidative stress in different neurodegenerative diseases through the modulation of various pathways including NRF-2, NADPH oxidase, TLR-4/MAPK, and TLR-4/NF-κB. This review article was developed through a comprehensive analysis and interpretation of research published between 2009 and 2024, sourced from multiple scientific databases, including PubMed, Scopus, ScienceDirect, and Web of Science. This review aims to provide an in-depth overview of the neuroprotective effects of kaempferol, focusing on its underlying molecular mechanisms. A total of 24 research evidence were included to elucidate the molecular pathways by which kaempferol exerts its protective effects against neurodegenerative diseases.

Electrochemical sensor for glutathione reductase based on screen-printed electrodes coated with 3,5-dinitrobenzoic acid-modified carbon nanotubes.

The preparation of a hybrid nanomaterial is reported by covalently attaching 3,5-dinitrobenzoic acid groups to the surface of oxidized multi-walled carbon nanotubes using 1,6-diaminohexane as cross-linking agent. This nanomaterial, modified with the redox mediator, was used as transduction element to construct an amperometric sensor for the efficient indirect determination of glutathione reductase at a low working potential of - 0.05 V, through the oxidation of unconsumed nicotinamide adenine dinucleotide phosphate (NADPH) in the enzymatic reaction. The sensor exhibited an excellent linear response in the range 1.6 to 174 µU/µL, with high reproducibility and selectivity. The developed device was successfully validated in real samples, accurately determining the active enzyme in diluted human serum, making it a promising alternative for the determination of glutathione reductase and other related NADPH-dependent enzymes with relevance in clinical analysis.

Identification of a novel NADPH generation reaction in the pentose phosphate pathway in Escherichia coli using mBFP.

NADPH is a redox cofactor that drives the anabolic reactions. Although major NADPH generation reactions have been identified in Escherichia coli, some minor reactions have not been identified. In the present study, we explored novel NADPH generation reactions by monitoring the fluorescence dynamics after the addition of carbon sources to starved cells, using a metagenome-derived blue fluorescent protein (mBFP) as an intracellular NADPH reporter. Perturbation analyses were performed on a glucose-6-phosphate isomerase (PGI) deletion strain and its parental strain. Interestingly, mBFP fluorescence increased not only in the parental strain but also in the ΔPGI strain after the addition of xylose. Because the ΔPGI strain cannot metabolize xylose through the oxidative pentose phosphate pathway, this suggests that an unexpected NADPH generation reaction contributes to an increase in fluorescence. To unravel this mystery, we deleted the NADPH generation enzymes including transhydrogenase, isocitrate dehydrogenase, NADP+-dependent malic enzyme, glucose-6-phosphate dehydrogenase (G6PDH), and 6-phosphogluconate dehydrogenase (6PGDH) in the ΔPGI strain, and revealed that G6PDH and 6PGDH contribute to an increase in fluorescence under xylose conditions. In vitro assays using purified enzymes showed that G6PDH can produce NADPH using erythrose-4-phosphate (E4P) as a substitute for glucose-6-phosphate. Because the Km (0.65 mM) for E4P was much higher than the reported intracellular E4P concentrations in E. coli, little E4P must be metabolized through this bypass in the parental strain. However, the flux would increase when E4P accumulates in the cells owing to genetic modifications. This finding provides a metabolic engineering strategy for generating NADPH to produce useful compounds using xylose as a carbon source.IMPORTANCEBecause NADPH is consumed during the synthesis of various useful compounds, enhancing NADPH regeneration is highly desirable in metabolic engineering. In this study, we explored novel NADPH generation reactions in Escherichia coli using a fluorescent NADPH reporter and found that glucose-6-phosphate dehydrogenase can produce NADPH using erythrose-4-phosphate as a substrate under xylose conditions. Xylose is an abundant sugar in nature and is an attractive carbon source for bioproduction. Therefore, this finding contributes to novel pathway engineering strategies using a xylose carbon source in E. coli to produce useful compounds that consume NADPH for their synthesis.

Simultaneous assessment of NAD(P)H and flavins with multispectral fluorescence lifetime imaging microscopy at a single excitation wavelength of 750 nm.

Significance: Autofluorescence characteristics of the reduced nicotinamide adenine dinucleotide and oxidized flavin cofactors are important for the evaluation of the metabolic status of the cells. The approaches that involve a detailed analysis of both spectral and time characteristics of the autofluorescence signals may provide additional insights into the biochemical processes in the cells and biological tissues and facilitate the transition of spectral fluorescence lifetime imaging into clinical applications. Aim: We present the experiments on multispectral fluorescence lifetime imaging with a detailed analysis of the fluorescence decays and spectral profiles of the reduced nicotinamide adenine dinucleotide and oxidized flavin under a single excitation wavelength aimed at understanding whether the use of multispectral detection is helpful for metabolic imaging of cancer cells. Approach: We use two-photon spectral fluorescence lifetime imaging microscopy. Starting from model solutions, we switched to cell cultures treated by metabolic inhibitors and then studied the metabolism of cells within tumor spheroids. Results: The use of a multispectral detector in combination with an excitation at a single wavelength of 750 nm allows the identification of fluorescence signals from three components: free and bound NAD(P)H, and flavins based on the global fitting procedure. Multispectral data make it possible to assess not only the lifetime but also the spectral shifts of emission of flavins caused by chemical perturbations. Altogether, the informative parameters of the developed approach are the ratio of free and bound NAD(P)H amplitudes, the decay time of bound NAD(P)H, the amplitude of flavin fluorescence signal, the fluorescence decay time of flavins, and the spectral shift of the emission signal of flavins. Hence, with multispectral fluorescence lifetime imaging, we get five independent parameters, of which three are related to flavins. Conclusions: The approach to probe the metabolic state of cells in culture and spheroids using excitation at a single wavelength of 750 nm and a fluorescence time-resolved spectral detection with the consequent global analysis of the data not only simplifies image acquisition protocol but also allows to disentangle the impacts of free and bound NAD(P)H, and flavin components evaluate changes in their fluorescence parameters (emission spectra and fluorescence lifetime) upon treating cells with metabolic inhibitors and sense metabolic heterogeneity within 3D tumor spheroids.

Obesity Promotes the Ceramide-Mediated NADPH Oxidase in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a type of blood cancer of the myeloid cell lineage. Obesity is characterized by an increase in body weight that results in excessive fat accumulation. Obesity has been associated with an increased incidence of many cancers, including blood cancers. This study evaluated the role obesity in AML progression in a novel transgenic mouse model developed by crossing Flt3ITD mice with Lepob/ob mice. Leukemia burden was augmented in obese AML mice. In addition, it was determined that obesity upregulated the ceramide-mediated and ceramide-1-phosphate-mediated NADPH oxidase 2 (NOX2). Notably, increased oxidative pathways has been attributed to disease progression in AML. Taken together, this study demonstrates a direct link between obesity and the progression of AML in part by augmenting the ceramide mediated NOX2.

Inducing disulfidptosis in tumors:potential pathways and significance.

Regulated cell death (RCD) is crucial for the elimination of abnormal cells. In recent years, strategies aimed at inducing RCD, particularly apoptosis, have become increasingly important in cancer therapy. However, the ability of tumor cells to evade apoptosis has led to treatment resistance and relapse, prompting extensive research into alternative death processes in cancer cells. A recent study identified a novel form of RCD known as disulfidptosis, which is linked to disulfide stress. Cancer cells import cystine from the extracellular environment via solute carrier family 7 member 11 (SLC7A11) and convert it to cysteine using nicotinamide adenine dinucleotide phosphate (NADPH). When NADPH is deficient or its utilization is impaired, cystine accumulates, leading to the formation of disulfide bonds in the actin cytoskeleton, triggering disulfidptosis. Disulfidptosis reveals a metabolic vulnerability in tumors, offering new insights into cancer therapy strategies. This review provides a detailed overview of the mechanisms underlying disulfidptosis, the current research progress, and limitations. It also highlights innovative strategies for inducing disulfidptosis and explores the potential of combining these approaches with traditional cancer therapies, particularly immunotherapy, to expedite clinical translation.

Endogenous histidine peptides are physiological antioxidants that prevent oligodendrocyte cell death and myelin loss in vivo.

Histidine dipeptides (HDs) are synthesized in brain oligodendrocytes by carnosine synthase (carns1), but their role is unknown. Using metabolomics and in vivo experiments with both constitutive and oligodendrocyte-selective carns1-KO mouse models, we found that HDs are critical for oligodendrocyte survival and protect against oxidative stress. Carns1-KO mouse models had lower numbers of mature oligodendrocytes, increased lipid peroxidation, and behavioral changes. Cuprizone administration, which increases reactive oxygen species in vivo, resulted in higher oligodendrocyte death, demyelination, axonal alterations, and oxidative damage in the corpus callosum of carns1-KO mice. Gliosis and oxidative damage by cuprizone were prevented by pretreatment with the antioxidant N-acetylcysteine. NADPH levels were increased threefold in the brains of carns1-KO mice as an antioxidant response to oxidative stress through acceleration of the pentose phosphate pathway (PPP). This was due to overexpression of glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the PPP. Likewise, expression of NAD kinase, the biosynthetic enzyme for NADP+, and NAMPT, which replenishes the NAD+ pool, was higher in carns1-KO mice brains than in controls. Our observations suggest that HDs cell-autonomously protect oligodendrocytes from oxidative stress, with implications for demyelinating diseases.

Regulation of cardiovascular diseases by histone deacetylases and NADPH oxidases.

Histone deacetylases (HDACs) play critical roles in cardiovascular diseases (CVDs). In addition, reactive oxygen species (ROS) produced by NADPH oxidases (NOXs) exert damaging effects due to oxidative stress on heart and blood vessels. Although NOX-dependent ROS production is implicated in pathogenesis, the relationship between HDACs and NOXs in CVDs remains to be elucidated. Here, we present an overview of the regulatory effects and interconnected signaling pathways of HDACs and NOXs in CVDs. Improved insights into these relationships will facilitate the discovery of novel therapeutic agents that target HDACs, oxidase stress pathways, and the interactions between these systems which may be highly effective in the prevention and treatment of cardiovascular disorders.

CysLT receptor-mediated NOX2 activation is required for IL-8 production in HMC-1 cells induced by Trichomonas vaginalis-derived secretory products.

Trichomoniasis is caused by a sexually transmitted flagellate protozoan parasite Trichomonas vaginalis. T. vaginalis-derived secretory products (TvSP) contain lipid mediators such as leukotriene B4 (LTB4) and various cysteinyl leukotrienes (CysLTs) which included LTC4, LTD4, and LTE4. However, the signaling mechanisms by which T. vaginalis-induced CysLTs stimulate interleukin (IL)-8 production in human mast cells remain unclear. In this study, we investigated these mechanisms in human mast cells (HMC-1). Stimulation with TvSP resulted in increased intracellular reactive oxygen species (ROS) generation and NADPH oxidase 2 (NOX2) activation compared to unstimulated cells. Pre-treatment with NOX2 inhibitors such as diphenyleneiodonium chloride (DPI) or apocynin significantly reduced ROS production in TvSP-stimulated HMC-1 cells. Additionally, TvSP stimulation increased NOX2 protein expression and the translocation of p47phox from the cytosol to the membrane. Pretreatment of HMC-1 cells with PI3K or PKC inhibitors reduced TvSP-induced p47phox translocation and ROS generation. Furthermore, NOX2 inhibitors or NOX2 siRNA prevented CREB phosphorylation and IL-8 gene expression or protein secretion induced by TvSP. Pretreatment with a CysLTR antagonist significantly inhibited TvSP-induced ROS production, CREB phosphorylation, and IL-8 production. These results indicate that CysLT-mediated activation of NOX2 plays a crucial role in ROS-dependent IL-8 production in human mast cells stimulated by T. vaginalis-secreted CysLTs. These findings enhance our understanding of the inflammatory response in trichomoniasis and may inform the development of targeted therapies to mitigate this response.

Melatonin Alleviates Osteoarthritis by Regulating NADPH Oxidase 4-Induced Ferroptosis and Mitigating Mitochondrial Dysfunction.

Recent evidence indicates that the damaged regions in osteoarthritis are accompanied by the accumulation of iron ions. Ferroptosis, as an iron-dependent form of cell death, holds significant implications in osteoarthritis. Melatonin, a natural product with strong scavenging abilities against reactive oxygen species and lipid peroxidation, plays a crucial role in the treatment of osteoarthritis. This study aims to demonstrate the existence of ferroptosis in osteoarthritis and explore the specific mechanism of melatonin in suppressing ferroptosis and alleviating osteoarthritis. Our findings reveal that melatonin reverses inflammation-induced oxidative stress and lipid peroxidation while promoting the expression of extracellular matrix components in chondrocytes, safeguarding the cells. Our research has revealed that NADPH oxidase 4 (NOX4) serves as a crucial molecule in the ferroptosis process of osteoarthritis. Specifically, NOX4 is located on mitochondria in chondrocytes, which can induce disorders in mitochondrial energy metabolism and dysfunction, thereby intensifying oxidative stress and lipid peroxidation. LC-MS analysis further uncovered that GRP78 is a downstream binding protein of NOX4. NOX4 induces ferroptosis by weakening GRP78's protective effect on GPX4 and reducing its expression. Melatonin can inhibit the upregulation of NOX4 on mitochondria and mitigate mitochondrial dysfunction, effectively suppressing ferroptosis and alleviating osteoarthritis. This suggests that melatonin therapy represents a promising new approach for the treatment of osteoarthritis.

Paricalcitol prevents renal tubular injury induced by ischemia-reperfusion: Role of oxidative stress, inflammation and AT1R.

The vitamin D receptor (VDR) is associated with antioxidative and anti-inflammatory effects and modulation of the renin-angiotensin-aldosterone system. This study evaluated whether VDR agonist paricalcitol protects renal ischemia-reperfusion (IR) induced tubular injury in rats by evaluating: 1) ATP-dependent tubular Na+ transport; 2) renal redox signaling; 3) renal content of proinflammatory cytokines TNF-α and IL-6; and 4) renal content of renin and angiotensin II receptor type 1 (AT1R). Paricalcitol prevented IR-induced tubular injury, evidenced by the prevention of histopathological changes and renal fibrosis with preservation of the activity of ATP-dependent Na+ transporters in the renal cortex. Paricalcitol decreased renal oxidative stress by reducing NADPH oxidase activity and increasing catalase. Paricalcitol also decreased the renal content of TNF-α, IL-6, and AT1R. The NADPH oxidase inhibitor apocynin did not present additive protection to paricalcitol-induced effects. The protective effects of paricalcitol on tubular injury induced by renal IR may dependent on the modulation of redox and proinflammatory signaling and renal angiotensin II/AT1R signaling.

CD11b-NOX2 mutual regulation-mediated microglial exosome release contributes to rotenone-induced inflammation and neurotoxicity in BV2 microglia and primary cultures.

Epidemiological studies have revealed a potent association between chronic exposure to rotenone, a commonly used pesticide, in individuals and the incidence of Parkinson's disease (PD). We previously identified the contribution of the activation of microglial NADPH oxidase (NOX2) in rotenone-induced neurotoxicity. However, the regulation of NOX2 activation remains unexplored. Integrins are known to be bidirectionally regulated in the plasma membrane through the inside-out and outside-in signaling. CD11b is the α-chain of integrin macrophage antigen complex-1. This study aimed to investigate whether CD11b mediates rotenone-induced NOX2 activation. We observed that rotenone exposure increased NOX2 activation in BV2 microglia, which was associated with elevated CD11b expression. Silencing CD11b significantly reduced rotenone-induced ROS production and p47phox phosphorylation, a key step for NOX2 activation. Furthermore, the Src-FAK-PKB and Syk-Vav1-Rac1 signaling pathways downstream of CD11b were found to be essential for CD11b-mediated NOX2 activation in rotenone-intoxicated microglia. Interestingly, we also found that inhibition of NOX2 decreased rotenone-induced CD11b expression, indicating a crosstalk between CD11b and NOX2. Subsequently, the inhibition of the CD11b-NOX2 axis suppressed rotenone-induced microglial activation and exosome release. Furthermore, inhibiting exosome synthesis in microglia blocked rotenone-induced gene expression of proinflammatory factors and related neurotoxicity. Finally, blocking the CD11b-NOX2 axis and exosome synthesis or endocytosis mitigated microglial activation and dopaminergic neurodegeneration in rotenone-intoxicated midbrain primary cultures. Our findings highlight the crucial involvement of the CD11b-NOX2 axis in rotenone-induced inflammation and neurotoxicity, offering fresh perspectives on the underlying mechanisms of pesticide-induced neuronal damage.