Hydrogen gas protects IP3Rs by reducing disulfide bridges in human keratinocytes under oxidative stress

TRPC7 facilitates cell growth and migration by regulating intracellular Ca2+ mobilization in lung adenocarcinoma cells

Transient receptor potential canonical 7 (TRPC7) has been reported to mediate aging-associated tumorigenesis, but the role of TRPC7 in cancer malignancy is still unclear. TRPC7 is associated with tumor size in patients with lung adenocarcinoma and the present study further evaluated the underlying mechanism of TRPC7 in the regulation of cancer progression. The clinicopathological role of TRPC7 was assessed using immunohistochemistry staining and the pathological mechanism of TRPC7 in lung adenocarcinoma cells was determined using cell cycle examination, invasion and calcium response assays, and immunoblot analysis. The results indicated that high TRPC7 expression was associated with a lower 5-year survival rate compared with low TRPC7 expression, which suggested that TRPC7 expression was inversely associated with overall survival in patients with lung adenocarcinoma. TRPC7 serves a pathological role by facilitating the enhancement of cell growth and migration with increased phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II, AKT and ERK. TRPC7 knockdown in lung adenocarcinoma cells restrained cell cycle progression and cell migration by interrupting the TRPC7-mediated Ca²⁺ signaling-dependent AKT and MAPK signaling pathways. These findings demonstrated for the first time a role of oncogenic TRPC7 in the regulation of cancer malignancy and could provide a novel therapeutic molecular target for patients with lung adenocarcinoma.

Hydrogen-Rich Water Can Restrict the Formation of Biogenic Amines in Red Beet Pickles

Fermented foods are considered the main sources of biogenic amines (BAs) in the human diet while lactic acid bacteria (LAB) are the main producers of BAs. Normal water (NW) and hydrogen-rich water (HRW) were used for preparing red beet pickles, i.e., NWP and HRWP, respectively. The formation of BAs, i.e., aromatic amines (tyramine, 2-phenylethylamine), heterocyclic amines (histamine, tryptamine), and aliphatic di-amines (putrescine), was analyzed in both beet slices and brine of NWPs and HRWPs throughout the fermentation stages. Significant differences in redox value (Eh7) between NWP and HRWP brine samples were noticed during the first and last fermentation stages with lower values found for HRWPs. Total mesophilic aerobic bacteria (TMAB), yeast–mold, and LAB counts were higher for HRWPs than NWPs for all fermentation stages. Throughout fermentation stages, the levels of all BAs were lower in HRWPs than those of NWPs, and their levels in brines were higher than those of beets. At the end of fermentation, the levels (mg/kg) of BAs in NWPs and HRWPs were, respectively: tyramine, 72.76 and 61.74 (beet) and 113.49 and 92.67 (brine), 2-phenylethylamine, 48.00 and 40.00 (beet) and 58.01 and 50.19 (brine), histamine, 67.89 and 49.12 (beet) and 91.74 and 70.92 (brine), tryptamine, 93.14 and 77.23 (beet) and 119.00 and 93.11 (brine), putrescine, 81.11 and 63.56 (beet) and 106.75 and 85.93 (brine). Levels of BAs decreased by (%): 15.15 and 18.35 (tyramine), 16.67 and 13.44 (2-phenylethylamine), 27.65 and 22.7 (histamine), 17.09 and 21.76 (tryptamine), and 21.64 and 19.5 (putrescine) for beet and brine, respectively, when HRW was used in pickle preparation instead of NW. The results of this study suggest that the best method for limiting the formation of BAs in pickles is to use HRW in the fermentation phase then replace the fermentation medium with a new acidified and brined HRW followed by a pasteurization process.

Combating Oxidative Stress and Inflammation in COVID-19 by Molecular Hydrogen Therapy: Mechanisms and Perspectives

COVID-19 is a widespread global pandemic with nearly 185 million confirmed cases and about four million deaths. It is caused by an infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which primarily affects the alveolar type II pneumocytes. The infection induces pathological responses including increased inflammation, oxidative stress, and apoptosis. This situation results in impaired gas exchange, hypoxia, and other sequelae that lead to multisystem organ failure and death. As summarized in this article, many interventions and therapeutics have been proposed and investigated to combat the viral infection-induced inflammation and oxidative stress that contributes to the etiology and pathogenesis of COVID-19. However, these methods have not significantly improved treatment outcomes. This may partly be attributable to their inability at restoring redox and inflammatory homeostasis, for which molecular hydrogen (H2), an emerging novel medical gas, may complement. Herein, we systematically review the antioxidative, anti-inflammatory, and antiapoptotic mechanisms of H2. Its small molecular size and nonpolarity allow H2 to rapidly diffuse through cell membranes and penetrate cellular organelles. H2 has been demonstrated to suppress NF-κB inflammatory signaling and induce the Nrf2/Keap1 antioxidant pathway, as well as to improve mitochondrial function and enhance cellular bioenergetics. Many preclinical and clinical studies have demonstrated the beneficial effects of H2 in varying diseases, including COVID-19. However, the exact mechanisms, primary modes of action, and its true clinical effects remain to be delineated and verified. Accordingly, additional mechanistic and clinical research into this novel medical gas to combat COVID-19 complications is warranted.

Mechanisms Underlying the Biological Effects of Molecular Hydrogen

Aberrant redox-sensitive reactions and accumulation of oxidative damage can impair body functions and contribute to the development of various pathologies and aging. Although antioxidant substances have long been recognized as a measure of alleviating oxidative stress and restoring redox balance, the arsenal of effective means of preventing the development of various disorders, is still limited. There is an emerging field that utilizes molecular hydrogen (H₂) as a scavenger of free radicals and reactive oxygen species (ROS). Among the remarkable characteristics of H₂ is its ability to counteract the harmful effects of hydroxyl radical and peroxynitrite without affecting the activity of functionally important ROS, such as hydrogen peroxide and nitric oxide. The beneficial effects of H₂ have been documented in numerous clinical studies and studies on animal models and cell cultures. However, the established scavenging activity of H₂ can only partially explain its beneficial effects because the effects are achieved at very low concentrations of H₂. Given the rate of H₂ diffusion, such low concentrations may not be sufficient to scavenge continuously generated ROS. H₂ can also act as a signaling molecule and induce defense responses. However, the exact targets and mechanism(s) by which H₂ exerts these effects are unknown. Here, we analyzed both positive and negative effects of the endogenous H₂, identified the redox-sensitive components of the pathways affected by molecular hydrogen, and also discussed the potential role of molecular hydrogen in regulating cellular redox.

MSC-derived exosomes protect against oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system

Oxidative stress is a major cause of skin injury induced by damaging stimuli such as UV radiation. Currently, owing to their immunomodulatory properties, mesenchymal stem cell-derived exosomes (MSC-Exo), as a nanotherapeutic agent, have attracted considerable attention. Here, we investigated the therapeutic effects of MSC-Exo on oxidative injury in H₂O₂-stimulated epidermal keratinocytes and UV-irradiated wild type and nuclear factor-erythroid 2-related factor-2 (Nrf2) knocked down cell and animal models. Our findings showed that MSC-Exo treatment reduced reactive oxygen species generation, DNA damage, aberrant calcium signaling, and mitochondrial changes in H₂O₂-stimulated keratinocytes or UV-irradiated mice skin. Exosome therapy also improved antioxidant capacities shown by increased ferric ion reducing antioxidant power and glutathione peroxidase or superoxide dismutase activities in oxidative stress-induced cell and skin injury. In addition, it alleviated cellular and histological responses to inflammation and oxidation in cell or animal models. Furthermore, the NRF2 signaling pathway was involved in the antioxidation activity of MSC-Exo, while Nrf2 knockdown attenuated the antioxidant capacities of MSC-Exo in vitro and in vivo, suggesting that these effects are partially mediated by the NRF2 signaling pathway. These results indicate that MSC-Exo can repair oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system. Thus, MSC-Exo may be used as a potential dermatological nanotherapeutic agent for treating oxidative stress-induced skin diseases or disorders.

Circulating messenger for neuroprotection induced by molecular hydrogen

Molecular hydrogen (H2) showed protection against various kinds of oxidative-stress-related diseases. First, it was reported that the mechanism of therapeutic effects of H2was antioxidative effect due to inhibition of the most cytotoxic reactive oxygen species, hydroxy radical (•OH). However, after chronic administration of H2in drinking water, oxidative-stress-induced nerve injury is significantly attenuated even in the absence of H2. It suggests indirect signaling of H2and gastrointestinal tract is involved. Indirect effects of H2could be tested by giving H2water only before nerve injury, as preconditioning. For example, preconditioning of H2for certain a period (∼7 days) in Parkinson’s disease model mice shows significant neuroprotection. As the mechanism of indirect effect, H2in drinking water induces ghrelin production and release from the stomach via β1-adrenergic receptor stimulation. Released ghrelin circulates in the body, being transported across the blood–brain barrier, activates its receptor, growth-hormone secretagogue receptor. H2-induced upregulation of ghrelin mRNA is also shown in ghrelin-producing cell line, SG-1. These observations help with understanding the chronic effects of H2and raise intriguing preventive and therapeutic options using H2.

A potential new approach for treating systemic sclerosis: Dedifferentiation of SSc fibroblasts and change in the microenvironment by blocking store-operated Ca2+ entry

Transforming growth factor-β (TGF-β) is an important target for treating systemic sclerosis (SSc). However, our study revealed three levels of TGF-β1 expression in SSc patients, indicating that inhibiting TGF-β is not sufficient to treat SSc. A previous clinical trial also displayed disappointing results. Thus, our study attempted to search for a potential novel approach. Ingenuity Pathway Analysis (IPA) indicated that the SSc pathological pathways were closely associated with store-operated Ca²⁺ entry (SOCE)-regulated signals, and SOCE activity was found to be increased in SSc fibroblasts. Further treatment of SSc fibroblasts with SOCE inhibitors, 2APB, and associated calcium channel inhibitors SKF96365, and indomethacin, showed that the SOCE inhibitors selectively decreased fibrosis markers and altered the cell morphology. Consequently, SOCE inhibitors, especially 2APB and indomethacin, caused the dedifferentiation of SSc fibroblasts via cytoskeleton remodeling and altered collagen secretion and restored the cell mobility. We further explained SSc pathogenesis as fibroblast differentiation with SOCE. Treatment with exogenous factors, gelatin-1, FAM20A and human albumin, which were identified from the conditioned medium of SSc fibroblasts, was important for regulating the differentiation of fibroblasts with higher levels of SOCE and α-SMA. Conclusively, to treat SSc, blockage of the increased SOCE activity in SSc induces the dedifferentiation of SSc fibroblasts and simultaneously changes the extracellular matrix (ECM) structure to limit SSc pathogenesis.

Hydrogen Indirectly Suppresses Increases in Hydrogen Peroxide in Cytoplasmic Hydroxyl Radical-Induced Cells and Suppresses Cellular Senescence

Bacteria inhabiting the human gut metabolize microbiota-accessible carbohydrates (MAC) contained in plant fibers and subsequently release metabolic products. Gut bacteria produce hydrogen (H₂), which scavenges the hydroxyl radical (•OH). Because H₂ diffuses within the cell, it is hypothesized that H₂ scavenges cytoplasmic •OH (cyto •OH) and suppresses cellular senescence. However, the mechanisms of cyto •OH-induced cellular senescence and the physiological role of gut bacteria-secreted H₂ have not been elucidated. Based on the pyocyanin-stimulated cyto •OH-induced cellular senescence model, the mechanism by which cyto •OH causes cellular senescence was investigated by adding a supersaturated concentration of H₂ into the cell culture medium. Cyto •OH-generated lipid peroxide caused glutathione (GSH) and heme shortage, increased hydrogen peroxide (H₂O₂), and induced cellular senescence via the phosphorylation of ataxia telangiectasia mutated kinase serine 1981 (p-ATM^ser1981)/p53 serine 15 (p-p53^ser15)/p21 and phosphorylation of heme-regulated inhibitor (p-HRI)/phospho-eukaryotic translation initiation factor 2 subunit alpha serine 51 (p-eIF2α)/activating transcription factor 4 (ATF4)/p16 pathways. Further, H₂ suppressed increased H₂O₂ by suppressing cyto •OH-mediated lipid peroxide formation and cellular senescence induction via two pathways. H₂ produced by gut bacteria diffuses throughout the body to scavenge cyto •OH in cells. Therefore, it is highly likely that gut bacteria-produced H₂ is involved in intracellular maintenance of the redox state, thereby suppressing cellular senescence and individual aging. Hence, H₂ produced by intestinal bacteria may be involved in the suppression of aging.

Effects of Post-Treatment Hydrogen Gas Inhalation on Uveitis Induced by Endotoxin in Rats

Background

Molecular hydrogen (H₂) has been widely reported to have benefiicial effects in diverse animal models and human disease through reduction of oxidative stress and inflammation. The aim of this study was to investigate whether hydrogen gas could ameliorate endotoxin-induced uveitis (EIU) in rats.

Material/Methods

Male Sprague-Dawley rats were divided into a normal group, a model group, a nitrogen-oxygen (N-O) group, and a hydrogen-oxygen (H-O) group. EIU was induced in rats of the latter 3 groups by injection of lipopolysaccharide (LPS). After that, rats in the N-O group inhaled a gas mixture of 67% N₂ and 33% O₂, while those in the H-O group inhaled a gas mixture of 67% H₂ and 33% O₂. All rats were graded according to the signs of uveitis after electroretinography (ERG) examination. Protein concentration in the aqueous humor (AqH) was measured. Furthermore, hematoxylin-eosin staining and immunostaining of anti-ionized calcium-binding adapter molecule 1 (Iba1) in the iris and ciliary body (ICB) were carried out.

Results

No statistically significant differences existed in the graded score of uveitis and the b-wave peak time in the Dark-adapted 3.0 ERG among the model, N-O, and H-O groups (P>0.05), while rats of the H-O group showed a lower concentration of AqH protein than that of the model or N-O group (P<0.05). The number of the infiltrating cells in the ICB of rats from the H-O group was not significantly different from that of the model or N-O group (P>0.05), while the activation of microglia cells in the H-O group was somewhat reduced (P<0.05).

Conclusions

Post-treatment hydrogen gas inhalation did not ameliorate the clinical signs, or reduce the infiltrating cells of EIU. However, it inhibited the elevation of protein in the AqH and reduced the microglia activation.