Acetaminophen (APAP) overdose has become the most common cause of acute liver failure. Ferroptosis plays a critical role in APAP-induced liver injury (AILI). Although inhibiting prolyl hydroxylase 2 (PHD2)-mediated degradation of hypoxia-inducible factor-1α (HIF-1α) can alleviate APAP hepatotoxicity, the function and underlying mechanism of PHD2/HIF-1 axis in APAP-induced ferroptosis are not fully understood. Here, we developed a novel anti-PHD2 cytoplasmic intrabody (INP2) and elucidated the anti-ferroptosis mechanism by which INP2 inhibits APAP hepatotoxicity. Our findings demonstrated that INP2 specifically recognized PHD2 and disrupted its interaction with HIF-1α, inhibiting HIF-1α hydroxylation and increasing HIF-1α stability. In the murine AILI model, INP2 pretreatment significantly protects against AILI by attenuating ferroptosis via restoring redox homeostasis, attenuating malondialdehyde and ROS accumulation, and decreasing ferrous iron content. Importantly, INP2 enhanced glutathione biosynthesis and eliminated oxidative stress by upregulating SLC7A11 and glutathione peroxidase 1 (GPX1), thereby decreasing cytotoxicity in APAP/HO-exposed hepatocytes. GPX1 knockdown markedly impaired INP2-mediated hepatoprotection and anti-ferroptosis by suppressing glutathione-dependent reduction of cytotoxic lipid hydroperoxides including 12-HPETE. Collectively, a PHD2-targeted intrabody protects acetaminophen-induced liver injury by attenuating ferroptosis via regulating PHD2/HIF-1α/GPX1 axis, which enhances glutathione biosynthesis, suppresses oxidative stress and ferroptosis, offering a potential strategy for the prevention and treatment of AILI.

This study aimed to explore the relationship between lifestyle factors and serum Klotho levels, as well as the mediating effect of blood glucose and systemic inflammation, in US adults. We analyzed data from 6024 participants (weighted to represent 245,378,415 U S. adults) aged ≥40 years from the National Health and Nutrition Examination Survey (NHANES) 2007-2016, using multiple linear regression and mediation analysis to investigate the associations between lifestyle factors, serum Klotho levels, blood glucose, and systemic immune-inflammation index(SII). Additionally, key cardiometabolic factors (blood pressure and low-density lipoprotein cholesterol, LDL-C) were incorporated as covariates, and both weighted and unweighted analyses were performed to validate result robustness. Results showed that lifestyle factors affect serum Klotho through metabolic and inflammatory pathways: systemic inflammation (SII) played a statistically significant but moderate mediating role in the association between lifestyle factors and serum Klotho, while glucose metabolism did not exhibit a significant mediating effect; physical activity (PA) showed no direct association with Klotho but had an indirect link via SII, with PA classified by intensity and age stratification. The study reveals complex interactions between lifestyle factors and serum Klotho levels, with blood glucose and systemic inflammation identified as potential key mediators of this association.

Mitophagy, oxidative stress, and ferroptosis are critical processes in the development of acute pancreatitis (AP). Transcription factor EB (TFEB), a key regulator of autophagy and lysosomal biogenesis, plays a central role in the pathogenesis of AP. However, its specific regulatory mechanisms within the mitophagy-oxidative stress-ferroptosis network remain incompletely understood. This study investigated the therapeutic potential of ginkgetin (GK), a natural TFEB activator, in AP. The results demonstrated that GK activated TFEB and subsequently significantly alleviated pathological damage in AP in vivo and effectively inhibited acinar cell death in vitro. Further mechanistic studies revealed that TFEB activation markedly improved impaired autophagic flux in AP, enhanced mitophagy, and simultaneously suppressed ferroptosis and oxidative stress. Specifically, TFEB upregulated the expression of the lysosomal marker LAMP1 to restore autophagy-lysosome function and induced the expression of BNIP3, a key mitophagy receptor, thereby enhancing mitochondrial quality control, restoring mitochondrial function, and ultimately mitigating oxidative stress and ferroptosis. Functional experiments confirmed that TFEB exerts its protective effects through nuclear translocation. When nuclear translocation was blocked by a C270S mutation-a mutation that disrupts TFEB dissociation from 14-3-3 proteins and subsequent nuclear localization-TFEB's regulatory roles in autophagy, mitophagy, ferroptosis, and oxidative stress were significantly inhibited. This study elucidates that TFEB, through nuclear translocation, not only restores basal autophagy but also enhances mitophagy, thereby collectively inhibiting oxidative stress and ferroptosis and alleviating the progression of AP. These findings provide a novel therapeutic strategy for AP.

The gut-testis axis is increasingly recognized as a regulator of male reproductive health; however, the key microbial contributors, metabolites, and underlying mechanisms remain unclear.

Exposure to microgravity induces a rapid and profound loss of bone mass, particularly in weight-bearing skeletal regions, closely resembling accelerated osteoporosis on Earth. Traditionally attributed to mechanical unloading, bone loss in space is now recognized as being strongly regulated by oxidative stress. Excessive production of reactive oxygen species (ROS)-driven by mitochondrial dysfunction, cosmic radiation, altered circadian rhythms, and fluid shifts-disrupts osteoblast differentiation, enhances osteoclastogenesis, and compromises osteocyte viability. These effects are mediated through redox-sensitive signaling pathways, including RANK/RANKL/OPG, Wnt/β-catenin, and MAPK, as well as transcriptional regulators such as NF-κB, ERK, and FoxO. Moreover, oxidative stress modulates epigenetic regulators, notably microRNAs and long non-coding RNAs, tipping gene networks toward apoptosis, autophagy dysregulation, and cellular senescence in bone cells. Beyond mechanistic insights, recent studies highlight the long-term persistence of skeletal deficits after spaceflight and reveal sex- and age-related vulnerabilities, particularly in postmenopausal women due to estrogen deficiency. These findings position oxidative stress as a central driver of skeletal deterioration with clear translational relevance to age-related osteoporosis. Current and emerging countermeasures target both the mechanical and redox dimensions of bone loss. Pharmacological strategies include antioxidants, bisphosphonates, NADPH oxidase inhibitors, mitochondrial stabilizers, and autophagy modulators. Nutritional interventions emphasize antioxidant-rich diets, vitamin D and calcium supplementation, and omega-3 fatty acids. Mechanical and biophysical countermeasures-resistance training, vibration therapy, and artificial gravity-remain essential, while innovative approaches such as redox-sensitive gene therapy, siRNA-based modulation, and mitochondria-targeted antioxidants offer new therapeutic avenues. By integrating mechanistic, epigenetic, and translational perspectives, this review underscores the centrality of redox imbalance in spaceflight-induced bone loss and identifies actionable targets for prevention. Ultimately, dissecting ROS-mitochondria-cell fate signaling provides a unifying framework for protecting astronaut skeletal health and advancing therapies for terrestrial osteoporosis.

Traumatic brain injury (TBI) induces direct mechanical injury and secondary injury processes, among which ferroptosis, a regulated and iron-dependent form of cell death, has emerged as a key mechanism. Circadian clock disruption is also commonly described in TBI patients and is reported to exacerbate pathological outcomes of TBI. However, the crosstalk between circadian clock dysfunction and ferroptosis in TBI remains unclear. Using a mouse TBI model, disrupted expression of core circadian clock regulators BMAL1, CLOCK, and PER2 was observed, accompanied by iron accumulation, blood-brain barrier (BBB) leakage, and neuronal damage. Ferroptosis inhibitors, melatonin (MLT) and liproxstatin-1 (Lip-1), alleviated TBI-induced weight loss and neurological dysfunction. In contrast to MLT, Lip-1 failed to rescue body temperature rhythmicity, although both agents modulated the circadian clock at the molecular level. Mechanistically, the Bmal1 downregulation sensitized HT-22 neurons to RSL3-induced ferroptosis in vitro by exacerbating oxidative stress and iron overload. Collectively, these findings demonstrated an asymmetric crosstalk, in which circadian clock disruption promotes ferroptosis, and inhibition of ferroptosis feeds back to modulate clock gene expression without restoring behavioral rhythms. This circadian-ferroptosis axis may represent a novel and promising target for therapeutic intervention in post-TBI neuroprotection.

Doxorubicin (DOX) is a frequently recommended chemotherapeutic agent. The dose-dependent and cumulative cardiotoxicity of DOX prevents its therapeutic use despite its clinical efficacy. Bergapten (BeG) is a naturally occurring furanocoumarin found in citrus fruits. We investigated the cardioprotective potential of BeG against DOX-induced cardiotoxicity. In both in vitro and in vivo models, BeG intervention lessens DOX-induced reactive oxygen species (ROS) generation, maintains mitochondrial membrane potential, lowers cardiomyocyte apoptosis, and restores the antioxidant defence system. Mechanistically, BeG mitigates oxidative damage by downregulating NADPH oxidase 4 (NOX4) expression, a key mediator of ROS production in cardiomyocytes. BeG intervention markedly impeded the DOX-induced downregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream antioxidant protein, heme oxygenase-1 (HO-1). In contrast, Nrf2 silencing abrogated the beneficial effects of BeG on DOX-treated H9c2 cells. These molecular events, through modulation of the NOX4/Nrf2/HO-1 signaling axis, collectively restore redox balance, reduce lipid peroxidation, and inhibit pro-apoptotic signaling by inhibiting the caspase-3 protein, while upregulating the anti-apoptotic Bcl-2 protein. Furthermore, BeG intervention improved echocardiography parameters, maintained cardiac histology, and reduced TUNEL-positive cells in DOX-treated animals. These findings suggest that BeG is a promising cardioprotective agent that targets key oxidative and apoptotic pathways and may be considered as an adjunctive therapy in DOX-induced toxicities.

Anthropogenic organotin pollutants, particularly triphenyltin chloride (TPTC), threaten aquatic ecosystems. However, their impact on tissue regeneration-a critical survival mechanism-remains poorly understood. Therefore, we used zebrafish larvae as a model organism to assess the effect of TPTC on caudal fin regeneration. We found that exposure to TPTC significantly inhibited caudal fin regeneration and affected the behavior of zebrafish larvae. In addition, TPTC increased the number of apoptotic cells and decreased the population of proliferating cells in the regenerating caudal fin. This was accompanied by dysregulated immune cell recruitment, manifested as a decrease in neutrophil numbers and an increase in macrophage numbers. TPTC exposure resulted in the inhibited Wnt pathway activity and the downregulation of core gene (wnt3a, fzd7a, β-catenin, lef1) expression levels during caudal fin. Critically, pharmacological activation of Wnt signaling using BML-284 rescued both regenerative capacity (75.2-84.1 % recovery) and the associated locomotor deficits. Together with exclusion of other major pathways, These results establish TPTC as an inhibitor of Wnt-mediated regeneration and reveal a novel ecotoxicological mechanism: pollutant at sub-lethal concentration levels exposure compromises tissue regeneration. This finding has broad implications for vertebrate resilience in contaminated habitats. And The remarkable fidelity of zebrafish caudal fin regeneration, coupled with its experimental tractability for genetic and chemical screening, has established it as a premier model for deciphering the core principles of vertebrate tissue repair.

Sepsis-associated encephalopathy (SAE) is a common and serious complication of sepsis, characterized by neuroinflammation and cognitive dysfunction, yet its molecular mechanisms remain unclear. This study aimed to investigate the role of heat shock protein 90α (HSP90α) in microglial NLRP3 inflammasome activation and cognitive impairment in SAE, and to explore the therapeutic potential of a small molecule compound, nicotinamide N-oxide (NAMO). SAE models were established using cecal ligation and puncture (CLP) in mice and LPS/ATP stimulated primary microglial cells/BV-2 cells. A combination of H&E/Nissl/TUNEL staining, transcriptomics, immunoblotting, qPCR, immunofluorescence, ELISA, mtDNA release, co-immunoprecipitation, molecular docking, AAV stereotaxic delivery, and pharmacological/siRNA interventions were utilized. Results showed that HSP90α expression was significantly upregulated in microglia during SAE. HSP90α facilitated NLRP3 inflammasome activation and exacerbated cognitive dysfunction in SAE by inducing mitochondrial dysfunction and promoting the release of mitochondrial DNA (mtDNA). Mechanistically, HSP90α interacted with PPP3CA, which facilitated Drp1 dephosphorylation at Ser637, triggering mitochondrial fragmentation and mtDNA release. Importantly, we identified that NAMO binds directly to HSP90α, inhibits the HSP90α-PPP3CA-Drp1 axis, reduces mtDNA release, and suppresses NLRP3 inflammasome activation. Administration of NAMO significantly alleviated cognitive impairment in SAE mice. Collectively, our findings reveal a novel HSP90α-PPP3CA-Drp1-mtDNA-NLRP3 signaling pathway in microglial activation and cognitive injury during SAE, and propose NAMO as a promising therapeutic candidate for SAE intervention.

Pulmonary arterial hypertension (PAH) is a progressive obstructive pulmonary vasculopathy characterized by pathological vascular remodeling driven by excessive cellular proliferation, apoptosis resistance, chronic inflammation, fibrotic deposition, and dysregulated vasoconstriction. As the disease advances, these vascular abnormalities culminate in right heart failure (RHF). The right ventricular (RV) initially undergoes compensatory hypertrophy but ultimately decompensates, manifesting as chamber dilation, impaired contractility, and progressive fibrosis. Despite the critical determinant role of RV functional reserve in patient survival and prognosis, but no clinically validated interventions directly address RV adaptation. Molecular hydrogen (H), a biologically safe therapeutic agent with exceptional antioxidative, anti-inflammatory, anti-apoptotic properties and autophagic flux-modulating activities, has demonstrated organoprotective efficacy in cardiovascular and cerebrovascular disorders. Nevertheless, its therapeutic potential in mitigating PAH-induced RHF remains unexplored. Clinical translation is hindered by hydrogen's high explosivity and low bioavailability, necessitating the development of safer and more efficient delivery strategies. This study developed novel hydrogen-releasing magnesium diboride nanosheets (MBNs), and employs an integrated transcriptomic-proteomic approach to investigate the cardioprotective effects of MBNs against PAH-induced RHF and elucidate its underlying molecular targets and mechanisms of action.

Redox imbalance and systemic oxidative stress are implicated in the pathophysiology of inflammatory bowel disease (IBD). Oxidative stress previously demonstrated strong associations with endoscopic disease activity in IBD. In this study, we aimed to prospectively evaluate a panel of redox proteins, including circulating total free thiols (FTs), low-molecular-weight thiols, and thioredoxin-1, as biomarkers for endoscopic disease activity in IBD.

Tubular cell death is a hallmark of acute kidney injury (AKI), yet its mechanisms remain unclear. This study elucidates the role of N6-adenosine-methyltransferase-like 3 (METTL3) in renal tubular pyroptosis. METTL3 was upregulated in ischemic AKI models and in hypoxia/reoxygenation (H/R)-treated tubular epithelial cells (TECs). Its silencing alleviated pyroptosis, while overexpression exacerbated it. Conditional METTL3 knockout in mouse TECs attenuated ischemia/reperfusion (I/R)-induced renal injury. Through m6A methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing, we identified TRAF-interacting protein with a forkhead-associated domain (TIFA) as a key target. METTL3 mediates m6A modification of TIFA mRNA, which is recognized by IGF2BP2 to enhance mRNA stability. TIFA promotes NLRP3 transcription via NF-κB signaling, activating the NLRP3 inflammasome and Caspase-1, thereby driving pyroptosis. Targeting METTL3 with tetrahedral framework nucleic acid-delivered siRNA reduced TIFA expression, mitigated renal dysfunction, and suppressed pyroptosis, highlighting the METTL3/TIFA/NLRP3 axis as a potential therapeutic target for AKI.

Androgenetic alopecia (AGA) is the most common form of hair loss globally. Despite its prevalence, only two FDA-approved drugs-minoxidil and finasteride-are currently available, underscoring the urgent need to discover novel biomarkers and therapeutic targets for AGA diagnosis, treatment, and monitoring.

Cardiovascular diseases are a major global health burden, and that is largely caused by premature aging of endothelial cells (ECs). Therefore, understanding of molecular mechanisms of EC aging is central to establishing novel therapeutic approaches. We have previously found that cells devoid of the transcription factor NRF2 are prematurely aged and identified numerous concomitant phenomena, among them extensive S-nitrosation (SNO) and increased expression of innate immunity regulators. As both could be putative reasons for the premature senescence, we aimed to establish their causative role. We found that the premature senescence of NRF2-deficient ECs is related to an overactivation of cGAS/STING pathway, a canonical modulator of innate immune response. To address the significance of abundant SNO, we used the model of S-nitrosoglutathione reductase (GSNOR), and we found that its deletion does not result in the induction of senescence or cGAS/STING activation. This supports a divergent outcome of increased SNO on EC phenotype. In the quest for a conducive mechanism, we characterized GSNOR-deficient ECs. We evidenced presence of atypical DNA cytoplasmic inclusions, abnormal structure and permeability of the nuclear envelope, along with changes in the actin cytoskeleton architecture. Interestingly, we found that the cytoplasmic DNA is not retained within ECs, but it is released out of the cell in an autophagy-dependent manner. Molecularly, we found that macrophage inhibitory factor (MIF) is an essential driver of this secretion. In sum, we have shown that premature senescence of NRF2-deficient ECs is triggered by overactivation of STING. In parallel, we have identified a pivotal role of GSNOR in ECs. This study advances the understanding of the mechanisms of the premature senescence of ECs and points out at cellular context-dependent outcome of enhanced SNO in ECs.

APOE4, the strongest genetic risk factor for sporadic Alzheimer's disease (AD), is closely associated with mitochondrial dysfunction, yet the mechanisms remain poorly defined. We identify a previously unrecognized failure of the Nrf2-PINK1/Parkin axis in APOE4 neurons that compromises mitochondrial quality control. Unlike APOE3, APOE4 neurons fail to activate PINK1/Parkin-dependent mitophagy under stress, a defect compounded by impaired Nrf2 signaling and weakened antioxidant defenses. In vivo, APOE4 mice show age-dependent collapse of this pathway, correlating with progressive mitochondrial dysfunction and disrupted mito-nuclear communication. Pharmacological activation of Nrf2 or PINK1 restores mitochondrial clearance, highlighting the axis as a druggable node. These findings provide a mechanistic link between APOE4 and mitochondrial failure, establishing the Nrf2-PINK1/Parkin pathway as a critical driver of neurodegeneration and a promising target for therapeutic intervention in AD.

Oxidative damage at the retinochoroidal interface manifests as retinal pigment epithelium (RPE) damage and subretinal macrophage accumulation. This study aimed to explore the role of oxidative stress (OS) in the RPE cells affecting metabolic reprogramming and associated molecular mechanisms in macrophages.

Hepatic encephalopathy (HE) induced cognitive decline has long been associated with mitochondrial dysfunction. Therefore, the present study aimed to characterize mitochondrial alterations in HE and also examining the regulatory role of Sirtuins. Using both in vitro (NHCl induced SH-SY5Y) and in vivo (bile duct ligation, BDL) models, mitochondrial analysis revealed pronounced abnormalities, including reduced membrane potential, elevated oxidative stress, and swelling. Moreover, spatial memory was also significantly impaired in BDL rats. Following HE, nuclear Sirtuins (Sirtuin 1, 6, and 7) were significantly downregulated, whereas Sirtuin 2-5 remained largely unchanged. Reduced Sirtuin 1 expression in HE resulted in decreased occupancy at the HIF-1α promoter, diminishing transcriptional repression and leading to aberrant HIF-1α upregulation. Elevated HIF-1α in turn enhanced transcriptional activation of VDAC1 in both HE models. Pharmacological activation of Sirtuin 1 with SRT2104 suppressed HIF-1α levels reduced VDAC1 expression, while inhibition with EX-527 exhibited the reverse effect and worsened mitochondrial dysfunction. Furthermore, selective VDAC1 inhibition by VBIT-12 effectively restored mitochondrial integrity in NHCl-treated cells. In addition to the Sirtuin 1-HIF-1α mechanism, a separate regulatory pathway involving Sirtuin 6 was also uncovered. Loss of Sirtuin 6 amplified HIF-1α transcriptional activity by reducing its interaction with Sirtuin 6 and diminishing Sirtuin 6-mediated repression, thereby promoting increased expression of the downstream target VDAC1. Together, these observations identify reduced nuclear Sirtuin 1 and Sirtuin 6 as converging upstream regulators of the HIF-1α-VDAC1 axis, contributing to mitochondrial dysfunction in HE.

Postmenopausal osteoporosis is a prevalent bone disorder characterized by an imbalance in bone homeostasis following estrogen decline, which leads to progressive bone loss. Research has shown that estrogen deprivation-induced osteoporosis (OVX) is partly dependent on the gut microbiota and its metabolites, a process that can be therapeutically targeted through supplementation with probiotics or the metabolites themselves. Multiple studies have revealed the multifaceted roles of indole and its derivatives in bone health and the pathophysiology of skeletal disorders. These compounds are exclusively synthesized from tryptophan by the gut microbiota. However, the underlying mechanisms and relationships of gut microbiota-derived indole and its derivatives in osteoporosis remain unclear. Our study aimed to explore the influence and mechanism of gut microbiota-derived indole and its derivatives on the development of osteoporosis. In this study, we confirmed that the gut microbiota was altered in OVX mouse model, which was manifested as decreased Lactobacillus genus in the gut and reduced levels of the related indoleacetic acid (IAA) in serum. IAA was significantly positively correlated with bone mass and the abundance of Lactobacillus genus. Specifically, IAA inhibited RANKL-induced PI3K-AKT signaling activation and ROS production, reduced NFATc1 nuclear translocation in BMMs, eventually suppressed osteoclast formation and bone resorption function. The agonist SC-79 restored the IAA-inhibited osteoclast formation. In vivo, daily IAA supplementation conferred protection from OVX-induced bone loss by significantly attenuating osteoclast resorption and enhancing Nrf2 expression. Overall, we elucidated the mechanisms of osteoclastogenesis during osteoporosis to facilitate the development of a new therapy using gut microbial metabolite IAA in addition to the existing therapeutics.

Adverse events in early life can alter the developmental trajectory of glial cells and neurons in the brain, increasing an individual's risk of developing neuropsychiatric disorders later in life. Retinoid X receptor alpha (RXRα), a member of the nuclear receptor superfamily, has been shown to exert protective effects on the central nervous system when activated. However, whether RXRα plays a role in maternal separation (MS) and the underlying mechanisms remain unclear. In this study, we used MS in BALB/c mice to simulate early-life stress, aiming to investigate the impact of MS on hippocampal neuronal development in mice during early life, as well as the neuroprotective role of RXRα and its mechanisms. The results showed that MS induced hippocampal neuronal damage and inhibited RXRα expression in offspring mice. In contrast, RXRα activation significantly ameliorated hippocampal neuronal damage in MS mice and exerted neuroprotective effects by suppressing oxidative stress, repairing mitochondrial dysfunction, reducing neuronal apoptosis, and promoting mitophagy. Further analysis revealed that bexarotene (an RXR agonist) exerted neuroprotective effects by upregulating the expression levels of RXRα and peroxisome proliferator-activated receptor gamma (PPARγ). In HT22 cells with hydrogen peroxide (HO)-induced damage, knockdown of PPARγ expression via small interfering RNA (siRNA) significantly attenuated the neuroprotective effect of RXRα activation against neuronal damage. In conclusion, MS impairs the development of hippocampal neurons in offspring mice, which may alter the developmental trajectory of the nervous system and increase the risk of neuropsychiatric disorders in adulthood. Activation of RXRα can effectively alleviate oxidative stress and neuronal damage in the hippocampus by improving mitochondrial dysfunction. Therefore, targeting RXRα holds promise as a potential strategy for treating the consequences of early-life trauma.

Omeprazole is a medically used proton pump inhibitor. It covalently modifies the H,K-ATPase responsible for acid production in the stomach. Omeprazole itself is an inactive sulfoxide. At acidic pH, it produces a sulfenic acid derivative in equilibrium with a sulfenamide, able to inhibit the pump. These activated derivatives can react with a thiol (RSH) to form a mixed disulfide, which gives a thioether in the presence of reductants. Hydrogen sulfide (HS), while toxic at high concentrations, exerts signaling and cytoprotective roles. We hypothesized that omeprazole could react with HS to form the corresponding persulfide (RSSH), which could decay to a disulfide and the corresponding thiols; alternatively, the persulfide could react with another HS to give the thioether derivative. We confirmed the reaction of omeprazole with HS at pH 4.5 by UV-Vis spectrophotometry. The reaction occurred in a timescale of minutes and required acid. Turbidity appeared and reverted with the reductant tris(2-carboxyethyl)phosphine, suggesting the formation of polysulfides and elemental sulfur. These products were confirmed by cyanolysis, reaction with a sulfane sulfur probe (SSP4), Raman spectroscopy and UV-Vis detection of solubilized elemental sulfur. HPLC-UV-Vis and mass spectrometry demonstrated the formation of the thioether derivative of omeprazole. No evidence was obtained for the formation of the disulfide of omeprazole or its thiol reduction products. Computational modeling revealed that the formation of the thioether is kinetically preferred over the formation of the disulfide. Overall, our results show that acid-activated omeprazole reacts with HS forming the thioether derivative of omeprazole, polysulfides and elemental sulfur.