Sirt3 mediates the protective effect of hydrogen in inhibiting ROS-induced retinal senescence

Magnesium implantation as a continuous hydrogen production generator for the treatment of myocardial infarction in rats

Molecular hydrogen is an emerging broad-spectrum antioxidant molecule that can be used to treat myocardial infarction (MI). However, with hydrogen inhalation, the concentration that can be reached within target organs is low and the duration of action is short, which makes it difficult to achieve high dose targeted delivery of hydrogen to the heart, seriously limiting the therapeutic potential of hydrogen for MI. As a result of reactions with the internal environment of the body, subcutaneous implantation of magnesium slices leads to continuous endogenous hydrogen production, leading to a higher hydrogen concentration and a longer duration of action in target organs. In this study, we propose magnesium implant-based hydrogen therapy for MI. After subcutaneous implantation of magnesium slices in the dorsum of rats, we measured hydrogen production and efficiency, and evaluated the safety of this approach. Compared with hydrogen inhalation, it significantly improved cardiac function in rats with MI. Magnesium implantation also cleared free radicals that were released as a result of mitochondrial dysfunction, as well as suppressing cardiomyocyte apoptosis.

Damage-Induced Senescent Immune Cells Regulate Regeneration of the Zebrafish Retina

Zebrafish spontaneously regenerate their retinas in response to damage through the action of Müller glia (MG). Even though MG are conserved in higher vertebrates, the capacity to regenerate retinal damage is lost. Recent work has focused on the regulation of inflammation during tissue regeneration, with temporal roles for macrophages and microglia. Senescent cells that have withdrawn from the cell cycle have mostly been implicated in aging but are still metabolically active, releasing a variety of signaling molecules as part of the senescence-associated secretory phenotype. Here, we discover that in response to retinal damage, a subset of cells expressing markers of microglia/macrophages also express markers of senescence. These cells display a temporal pattern of appearance and clearance during retina regeneration. Premature removal of senescent cells by senolytic treatment led to a decrease in proliferation and incomplete repair of the ganglion cell layer after N-methyl-D-aspartate damage. Our results demonstrate a role for modulation of senescent cell responses to balance inflammation, regeneration, plasticity, and repair as opposed to fibrosis and scarring.

Local H2 release remodels senescence microenvironment for improved repair of injured bone

The senescence microenvironment, which causes persistent inflammation and loss of intrinsic regenerative abilities, is a main obstacle to effective tissue repair in elderly individuals. In this work, we find that local H2 supply can remodel the senescence microenvironment by anti-inflammation and anti-senescence effects in various senescent cells from skeletally mature bone. We construct a H2-releasing scaffold which can release high-dosage H2 (911 mL/g, up to 1 week) by electrospraying polyhydroxyalkanoate-encapsulated CaSi2 nanoparticles onto mesoporous bioactive glass. We demonstrate efficient remodeling of the microenvironment and enhanced repair of critical-size bone defects in an aged mouse model. Mechanistically, we reveal that local H2 release alters the microenvironment from pro-inflammation to anti-inflammation by senescent macrophages repolarization and secretome change. We also show that H2 alleviates the progression of aging/injury-superposed senescence, facilitates the recruitment of endogenous cells and the preservation of their regeneration capability, thereby creating a pro-regenerative microenvironment able to support bone defect regeneration.

Novel Role of Molecular Hydrogen: The End of Ophthalmic Diseases?

Molecular hydrogen (H2) is a colorless, odorless, and tasteless gas which displays non-toxic features at high concentrations. H2 can alleviate oxidative damage, reduce inflammatory reactions and inhibit apoptosis cascades, thereby inducing protective and repairing effects on cells. H2 can be transported into the body in the form of H2 gas, hydrogen-rich water (HRW), hydrogen-rich saline (HRS) or H2 produced by intestinal bacteria. Accumulating evidence suggest that H2 is protective against multiple ophthalmic diseases, including cataracts, dry eye disease, diabetic retinopathy (DR) and other fields. In particular, H2 has been tested in the treatment of dry eye disease and corneal endothelial injury in clinical practice. This medical gas has brought hope to patients suffering from blindness. Although H2 has demonstrated promising therapeutic potentials and broad application prospects, further large-scale studies involving more patients are still needed to determine its optimal application mode and dosage. In this paper, we have reviewed the basic characteristics of H2, and its therapeutic effects in ophthalmic diseases. We also focus on the latest progress in the administration approaches and mechanisms underlying these benefits.

Spermidine Retarded the Senescence of Multipotent Mesenchymal Stromal Cells In Vitro and In Vivo through SIRT3-Mediated Antioxidation

Multipotent mesenchymal stromal cells (MSCs) expand in vitro and undergo replicative senescence, thereby restricting their clinical utilization. Thus, an effective strategy is required to impede MSC senescence. Since spermidine (SPD) supplementation can prolong the lifespan of yeast by inhibiting oxidative stress, spermidine is a potential option for delaying MSC senescence. In this study, to test our hypothesis, we first isolated primary human umbilical cord mesenchymal stem cells (hUCMSCs). Subsequently, the appropriate SPD dose was administered during continuous cell cultivation. Next, we evaluated the antisenescence effects by SA-β-gal staining, Ki67 expression, reactive oxygen species (ROS) levels, adipogenic or osteogenic ability, senescence-associated markers, and DNA damage markers. The results revealed that early SPD intervention significantly delays the replicative senescence of hUCMSCs and constrains premature H₂O₂-induced senescence. Additionally, by silencing SIRT3, the SPD-mediated antisenescence effects disappear, further demonstrating that SIRT3 is necessary for SPD to exert its antisenescence effects on hUCMSCs. Besides, the findings of this study also suggest that SPD in vivo protects MSCs against oxidative stress and delays cell senescence. Thus, MSCs maintain the ability to proliferate and differentiate efficiently in vitro and in vivo, which reflects the potential clinical utilization of MSCs in the future.

HOTAIR regulates SIRT3-mediated cardiomyocyte survival after myocardial ischemia/reperfusion by interacting with FUS

BACKGROUND

Myocardial ischemia/reperfusion (I/R) contributes to serious myocardial injury and even death. Therefore, prevention and mitigation of myocardial I/R is particularly important. LncRNA HOTAIR has been reported to be implicated in myocardial I/R progression. However, the detailed molecular mechanism of HOTAIR in cardiomyocyte was explored in myocardial I/R.

METHODS

Firstly, cell model of myocardial I/R was established through hypoxia/reoxygenation (H/R). Apoptosis and cell cycle were evaluated utilizing flow cytometry. The corresponding test kits were conducted to monitor the levels of LDH, Caspase3 and Caspase9. The gene expression and protein levels were detected by qPCR and western blot, respectively. RNA pull-down and RIP were performed to verify the interaction between FUS and lncRNA HOTAIR.

RESULTS

In AC16 cardiomyocytes treated with H/R, lncRNA HOTAIR and SIRT3 expression were obviously decreased. Overexpression of HOTAIR or SIRT3 could ameliorate H/R-induced cardiomyocyte injury by promoting cell viability, lowering LDH levels, and suppressing cell apoptosis. Further, lncRNA HOTAIR upregulated the expression of SIRT3 via interacting with FUS, thereby promoting the survival of H/R-injured cardiomyocytes.

CONCLUSION

LncRNA HOTAIR can improve myocardial I/R by affecting cardiomyocyte survival through regulation of SIRT3 by binding to the RNA binding protein FUS.

Damage-induced senescent immune cells regulate regeneration of the zebrafish retina

Zebrafish spontaneously regenerate their retina in response to damage through the action of Müller glia. Even though Müller glia (MG) are conserved in higher vertebrates, the capacity to regenerate retinal damage is lost. Recent work has focused on the regulation of inflammation during tissue regeneration with precise temporal roles for macrophages and microglia. Senescent cells that have withdrawn from the cell cycle have mostly been implicated in aging, but are still metabolically active, releasing proinflammatory signaling molecules as part of the Senescence Associated Secretory Phenotype (SASP). Here, we discover that in response to retinal damage, a subset of cells expressing markers of microglia/macrophages also express markers of senescence. These cells display a temporal pattern of appearance and clearance during retina regeneration. Premature removal of senescent cells by senolytic treatment led to a decrease in proliferation and incomplete repair of the ganglion cell layer after NMDA damage. Our results demonstrate a role for modulation of senescent cell responses to balance inflammation, regeneration, plasticity, and repair as opposed to fibrosis and scarring.

FFAR4 improves the senescence of tubular epithelial cells by AMPK/SirT3 signaling in acute kidney injury

Acute kidney injury (AKI) is a serious clinical complication with high morbidity and mortality rates. Despite substantial progress in understanding the mechanism of AKI, no effective therapy is available for treatment or prevention. We previously found that G protein-coupled receptor (GPCR) family member free fatty acid receptor 4 (FFAR4) agonist TUG891 alleviated kidney dysfunction and tubular injury in AKI mice. However, the versatile role of FFAR4 in kidney has not been well characterized. In the study, the expression of FFAR4 was abnormally decreased in tubular epithelial cells (TECs) of cisplatin, cecal ligation/perforation and ischemia/reperfusion injury-induced AKI mice, respectively. Systemic and conditional TEC-specific knockout of FFAR4 aggravated renal function and pathological damage, whereas FFAR4 activation by TUG-891 alleviated the severity of disease in cisplatin-induced AKI mice. Notably, FFAR4, as a key determinant, was firstly explored to regulate cellular senescence both in injured kidneys of AKI mice and TECs, which was indicated by senescence-associated β-galactosidase (SA-β-gal) activity, marker protein p53, p21, Lamin B1, phospho-histone H2A.X, phospho-Rb expression, and secretory phenotype IL-6 level. Mechanistically, pharmacological activation and overexpression of FFAR4 reversed the decrease of aging-related SirT3 protein, where FFAR4 regulated SirT3 expression to exhibit anti-senescent effect via Gq subunit-mediated CaMKKβ/AMPK signaling in cisplatin-induced mice and TECs. These findings highlight the original role of tubular FFAR4 in cellular senescence via AMPK/SirT3 signaling and identify FFAR4 as a potential drug target against AKI.

Endothelial NOX4 aggravates eNOS uncoupling by decreasing dihydrofolate reductase after subarachnoid hemorrhage

Endothelial malfunction is a major contributor to early or delayed vasospasm after subarachnoid hemorrhage (SAH). As a representative form of endothelial dysfunction, endothelial nitric oxide synthase (eNOS) uncoupling leads to a reduction in nitric oxide (NO) generated by endothelial cells. In this study, we investigated how the interaction between endothelial NOX4 (nicotinamide adenine dinucleotide phosphate oxidase 4) and DHFR (dihydrofolate reductase) contributes to eNOS uncoupling after SAH. Setanaxib and the adeno-associated virus (AAV) targeting brain vascular endothelia were injected through the tail vein and the expression and localization of proteins were examined by western blot and immunofluorescence staining. The NO content was measured using the NO assay kit, and laser speckle contrast imaging was used to assess cortical perfusion. ROS (reactive oxygen species) level was detected by DHE (dihydroethidium) staining, DCFH-DA (2',7'-dichlorofluorescin diacetate) staining and H₂O₂ (hydrogen peroxide) measurement. The Garcia score was employed to examine neurological function. Setanaxib is widely used for its preferential inhibition for NOX1/4 over other NOX isoforms. After endothelial NOX4 was inhibited by Setanaxib in a mouse model of SAH, the endothelial DHFR level was significantly elevated, which attenuated eNOS uncoupling, increased cortical perfusion, and improved the neurological function. The protective role of inhibiting endothelial NOX4, however, disappeared after knocking down endothelial DHFR. Our results suggest that endothelial DHFR decreased significantly because of the elevated level of endothelial NOX4, which aggravated eNOS uncoupling after SAH, leading to decreased cortical perfusion and worse neurological outcome.

Role of Carbon Monoxide in Oxidative Stress-Induced Senescence in Human Bronchial Epithelium

Prolonged or excessive stimulation from inhaled toxins may cause oxidative stress and DNA damage that can lead to stress-induced senescence in epithelial cells, which can contribute to several airway diseases. Mounting evidence has shown carbon monoxide (CO) confers cytoprotective effects. We investigated the effects of CO on oxidative stress-induced senescence in human airway epithelium and elucidated the underlying molecular mechanisms. Here, CO pretreatment reduced H₂O₂-mediated increases in total reactive oxygen species (ROS) production and mitochondrial superoxide in a human bronchial epithelial cell line (BEAS-2B). H₂O₂ treatment triggered a premature senescence-like phenotype with enlarged and flattened cell morphology accompanied by increased SA-β-gal activity, cell cycle arrest in G0/G1, reduced cell viability, and increased transcription of senescence-associated secretory phenotype (SASP) genes. Additionally, exposure to H₂O₂ increased protein levels of cellular senescence markers (p53 and p21), reduced Sirtuin 3 (SIRT3) and manganese superoxide dismutase (MnSOD) levels, and increased p53 K382 acetylation. These H₂O₂-mediated effects were attenuated by pretreatment with a CO-containing solution. SIRT3 silencing induced mitochondrial superoxide production and triggered a senescence-like phenotype, whereas overexpression decreased mitochondrial superoxide production and alleviated the senescence-like phenotype. Air-liquid interface (ALI) culture of primary human bronchial cells, which becomes a fully differentiated pseudostratified mucociliary epithelium, was used as a model. We found that apical and basolateral exposure to H₂O₂ induced a vacuolated structure that impaired the integrity of ALI cultures, increased goblet cell numbers, decreased SCGB1A1+ club cell numbers, increased p21 protein levels, and increased SASP gene transcription, consistent with our observations in BEAS-2B cells. These effects were attenuated in the apical presence of a CO-containing solution. In summary, we revealed that CO has a pivotal role in epithelial senescence by regulating ROS production via the SIRT3/MnSOD/p53/p21 pathway. This may have important implications in the prevention and treatment of age-associated respiratory pathologies.

The effect of a chrysanthemum water extract in protecting the retina of mice from light damage

Background

Oxidative stress can induce age-related diseases. Age-related retinal diseases, such as age-related macular degeneration (AMD), are difficult to cure owing to their complicated mechanisms. Although anti-neovascular therapeutics are used to treat wet AMD, vision cannot always be completely restored, and disease progression cannot always be inhibited. Therefore, determining a method to prevent or slow retinal damage is important. This study aimed to investigate the protective effect of a chrysanthemum water extract rich in flavone on the oxidatively stressed retina of mice.

Methods

Light damage was induced to establish oxidative stress mouse models. For in vitro experiments, ARPE-19 cells were cultured and divided into four groups: control, light-damaged, and low- and high-dose chrysanthemum extract. No treatment was administered in the control group. The light-damaged and low- and high-dose chrysanthemum extract groups were exposed to a similar white light level. The chrysanthemum extract was added at a low dose of 0.4 mg/mL or a high dose of 1.0 mg/mL before cell exposure to 2500-lx white light. Reactive oxygen species (ROS) level and cellular viability were measured using MTT and immunofluorescence staining. For in vivo experiments, C57BL/6 J mice were divided into the same four groups. Low- (0.23 g/kg/day) and high-dose (0.38 g/kg/day) chrysanthemum extracts were continuously intragastrically administered for 8 weeks before mouse exposure to 10,000-lx white light. Retinal function was evaluated using electroretinography. In vivo optical coherence tomography and in vitro haematoxylin and eosin staining were performed to observe the pathological retinal changes in each group after light damage. Fluorescein fundus angiography of the arteriovenous vessel was performed, and the findings were analysed using the AngioTool software. TUNEL immunofluorescence staining was used to assess isolated retinal apoptosis.

Results

In vitro, increased ROS production and decreased ARPE-19 cell viability were found in the light-damaged group. Improved ARPE-19 cell viability and reduced ROS levels were observed in the chrysanthemum extract treatment groups. In vivo, dysfunctional retinas and abnormal retinal structures were found in the light-damaged group, as well as increased apoptosis in the retinal ganglion cells (RGCs) and inner and outer nuclear layers. The apoptosis rate in the same layers was lower in the chrysanthemum extract treatment groups than in the light-damaged group. The production of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), increased in the treatment groups. NF-κB in the nucleus and TNF-α were more highly expressed in the light-damaged group than in the low- and high-dose chrysanthemum extract groups.

Conclusions

Light damage-induced retinal oxidative stress can lead to ROS accumulation in the retinal tissues. Herein, RGC and photoreceptor layer apoptosis was triggered, and NF-κB in the nucleus and TNF-α were highly expressed in the light-damaged group. Preventive chrysanthemum extract administration decreased ROS production by increasing SOD, CAT, and GSH-Px activities and reversing the negative changes, demonstrating a potential protective effect on the retina.

Nicotinamide Mononucleotide Ameliorates Cellular Senescence and Inflammation Caused by Sodium Iodate in RPE

Senescent cells have been demonstrated to have lower cellular NAD⁺ levels and are involved in the development of various age-related diseases, including age-related macular degeneration (AMD). Sodium iodate (NaIO₃) has been primarily used as an oxidant to establish a model of dry AMD. Results of previous studies have showed that NaIO₃ induced retinal tissue senescence in vivo. However, the role of NaIO₃ and the mechanism by which it induces retinal pigment epithelium (RPE) senescence remains unknown. In this study, RPE cell senescence was confirmed to be potentially induced by NaIO₃. The results showed that the number of senescence-associated-β-galactosidase (SA-β-gal-)-positive cells and the protein levels of p16 and p21 increased after NaIO₃ treatment. Additionally, the senescent RPE cells underwent oxidative stress and NAD⁺ depletion. Furthermore, significant DNA damage and mitochondrial dysfunction were also detected in senescent RPE cells. The antioxidant N-acetylcysteine (NAC) could alleviate cellular senescence only by a minimal degree, whereas supplementation with nicotinamide mononucleotide (NMN) strongly ameliorated RPE senescence through the alleviation of DNA damage and the maintenance of mitochondrial function. The protective effects of NMN were demonstrated to rely on undisturbed Sirt1 signaling. Moreover, both the expression of senescence markers of RPE and subretinal inflammatory cell infiltration were decreased by NMN treatment in vivo. Our results indicate that RPE senescence induced by NaIO₃ acquired several key features of AMD. More importantly, NMN may potentially be used to treat RPE senescence and senescence-associated pre-AMD changes by restoring the NAD⁺ levels in cells and tissues.

Role of Molecular Hydrogen in Ageing and Ageing-Related Diseases

Ageing is a physiological process of progressive decline in the organism function over time. It affects every organ in the body and is a significant risk for chronic diseases. Molecular hydrogen has therapeutic and preventive effects on various organs. It has antioxidative properties as it directly neutralizes hydroxyl radicals and reduces peroxynitrite level. It also activates Nrf2 and HO-1, which regulate many antioxidant enzymes and proteasomes. Through its antioxidative effect, hydrogen maintains genomic stability, mitigates cellular senescence, and takes part in histone modification, telomere maintenance, and proteostasis. In addition, hydrogen may prevent inflammation and regulate the nutrient-sensing mTOR system, autophagy, apoptosis, and mitochondria, which are all factors related to ageing. Hydrogen can also be used for prevention and treatment of various ageing-related diseases, such as neurodegenerative disorders, cardiovascular disease, pulmonary disease, diabetes, and cancer. This paper reviews the basic research and recent application of hydrogen in order to support hydrogen use in medicine for ageing prevention and ageing-related disease therapy.

Molecular hydrogen is a promising therapeutic agent for pulmonary disease

Molecular hydrogen exerts biological effects on nearly all organs. It has anti-oxidative, anti-inflammatory, and anti-aging effects and contributes to the regulation of autophagy and cell death. As the primary organ for gas exchange, the lungs are constantly exposed to various harmful environmental irritants. Short- or long-term exposure to these harmful substances often results in lung injury, causing respiratory and lung diseases. Acute and chronic respiratory diseases have high rates of morbidity and mortality and have become a major public health concern worldwide. For example, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. An increasing number of studies have revealed that hydrogen may protect the lungs from diverse diseases, including acute lung injury, chronic obstructive pulmonary disease, asthma, lung cancer, pulmonary arterial hypertension, and pulmonary fibrosis. In this review, we highlight the multiple functions of hydrogen and the mechanisms underlying its protective effects in various lung diseases, with a focus on its roles in disease pathogenesis and clinical significance.

TREM2 Ameliorates Lipopolysaccharide-Induced Oxidative Stress Response and Neuroinflammation by Promoting Sirtuin3 in BV2 Cells

Triggering receptor expressed on myeloid cells 2 (TREM2) plays a crucial role in modulating microglial-mediated neuroinflammation. The NAD-dependent deacetylase protein Sirtuin 3 (SIRT3) regulates mitochondrial oxidative stress response and neuroinflammation. TREM2 deficiency impairs the denovo synthesis pathway of NAD⁺. Therefore, the aim of this study was to investigate the potential role of TREM2 and SIRT3 in LPS-induced oxidative stress and neuroinflammation in BV2 cells. Lentivirus vector-mediated TREM2 overexpression (TREM2-OE) and corresponding negative control vector (TREM2-NC) were synthesized. BV2 cells were treated with LPS and/or TREM2-OE. 3-TYP, a selective SIRT3 inhibitor, was applied to determine the role of SIRT3 in the anti-oxidant and anti-inflammatory effects of TREM2. TREM2, SIRT3, NLRP3 inflammasome, caspase-1, postsynaptic density-95 (PSD-95), and brain derived neurotrophic factor (BDNF) were measured by Western blot analysis. Superoxide dismutase (SOD) was tested by SOD Assay Kit. Reactive oxygen species (ROS) expression was examined by immunofluorescence. Interleukin 1β (IL-1β) was determined by ELISA. Contents of NAD⁺ and NADH were detected by WST-8 method. LPS (1ug/ml for 24 h) significantly decreased TREM2 expression at both RNA and protein levels (p < 0.01 and p < 0.05, respectively). Lower levels of SIRT3 protein and NAD⁺ were also detected following LPS stimulation (p < 0.05 and p < 0.05, respectively). LPS significantly enhanced ROS, NLRP3, caspase-1, and IL-1β expression (p < 0.01, p < 0.05, p < 0.05, and p < 0.01, respectively). PSD-95 and BDNF expression were decreased triggered by LPS (p < 0.05 and p < 0.05, respectively). TREM2 overexpression enhanced NAD⁺ and SIRT3 protein expression following LPS challenge in BV2 cells (p < 0.01 and p < 0.05, respectively). TREM2 alleviated LPS-induced oxidative stress and neuroinflammation (p < 0.01 and p < 0.05, respectively). Similarly, TREM2 overexpression upregulated PSD-95 and BDNF expression (p < 0.05 and p < 0.05, respectively). The anti-oxidant and anti-inflammatory effects of TREM2 were partially abrogated by SIRT3 antagonist 3-TYP (p < 0.05 and p < 0.05, respectively). Similarly, selective SIRT3 inhibition also partially abrogated TREM2-induced BDNF protein upregulation (p < 0.05) but failed to influence PSD-95 protein expression following LPS stimulation. LPS induces oxidative stress and neuroinflammation in BV2 cells, which may be mediated in part by the downregulation of TREM2 and SIRT3. TREM2 overexpression ameliorates LPS-induced oxidative stress and neuroinflammation through enhancing SIRT3 function via NAD⁺.

Cardioprotective effect of rosmarinic acid against myocardial ischaemia/reperfusion injury via suppression of the NF-κB inflammatory signalling pathway and ROS production in mice

CONTEXT

Rosmarinic acid (RosA), a natural poly-phenolic compound isolated from a variety of Labiatae herbs, has been reported to have a range of biological effects.

OBJECTIVE

To investigate the cardioprotective effects of RosA against myocardial ischaemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

Male C57BL/6J mice were given RosA (100 mg/kg) via intragastric administration. After 1 week of administration, the mice were subjected to 30 min/24 h myocardial I/R injury. The mice were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + I/R, and RosA + I/R. Infarct size (IS), cardiac function (including EF, FS), histopathology, serum enzyme activities, ROS changes, cis aconitase (ACO) activity, and specific mRNA and protein levels were assessed in vivo. HL-1 cells were pre-treated with or without RosA (50 μM), followed by stimulation with 9 h/6 h of oxygen and glucose deprivation/re-oxygenation (OGD/R). The cells were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + OGD/R, and RosA + OGD/R. Lactate dehydrogenase (LDH) levels, ACO activity, ROS changes and protein levels were measured in vitro.

RESULTS

Treatment with RosA reduced the following indicators in vivo (p < 0.05): (1) IS (14.5%); (2) EF (-23.4%) and FS (-18.4%); (3) the myocardial injury enzymes CK-MB (20.8 ng/mL) and cTnI (7.7 ng/mL); (4) DHE-ROS: (94.1%); (5) ACO activity (-2.1 mU/mg protein); (6) ogdh mRNA level (122.9%); and (7) OGDH protein level (69.9%). Moreover, treatment with RosA attenuated the following indicators in vitro (p < 0.05): (1) LDH level (191 U/L); (2) DHE-ROS: (165.2%); (3) ACO activity (-3.2 mU/mg protein); (4) ogdh mRNA level (70.0%); and (5) OGDH (110.1%), p-IκB-a (56.8%), and p-NF-κB (57.7%) protein levels.

CONCLUSIONS

RosA has the potential to treat myocardial I/R injury with potential application in the clinic.

Metformin protects against inflammation, oxidative stress to delay poly I:C-induced aging-like phenomena in gut of an annual fish

Metformin, a clinical agent of type 2 diabetes, is reported as a potential geroprotector. Viral infection induces phenotypes of senescence in human T cells, and polyinosinic:polycytidylic acid (poly I:C), a viral mimic, induces upregulation of SA-β-gal activity in ovary of the annual fish Nothobranchius guentheri. However, the effects and mechanisms of metformin on poly I:C-induced aging-like phenomena are poorly understood in vertebrates. In this study, the activity of SA-β-gal increased in gut of 12-month-old fish and poly I:C-injected 6-month-old fish, compared to 6-month-old control fish, indicating that poly I:C induces aging-like phenomena in gut of the fish. Metformin supplementation retarded accumulation of SA-β-gal in gut of old fish and poly I:C-treated young fish. The results of q-PCR analysis showed that metformin reduced NF-κB mediated inflammatory response including decreased level of pro-inflammatory cytokine IL-8 and increased expression of anti-inflammatory cytokine IL-10 in gut of the fish with natural aging and poly I:C-injected 6-month-old fish. Metformin also exhibited antioxidant effects, as it reduced ROS production which is associated with the upregulation of FoxO3a and PGC-1α in gut of 6-month-old fish with poly I:C-injection. Expression of AMPK and SIRT1 was reduced in gut of 6-month-old fish with poly I:C-treatment, and feeding metformin reversed these declines. Taken together, the present study suggested that poly I:C-injection led to aging-like phenomena in gut and metformin activated AMPK and SIRT1 to reduce NF-κB mediated inflammation and resist oxidative stress via enhanced expression of FoxO3a and PGC-1α, and finally delayed gut aging in vertebrates.

SIRT3 mitigates intervertebral disc degeneration by delaying oxidative stress-induced senescence of nucleus pulposus cells

Senescence of nucleus pulposus (NP) cells (NPC) is a major cause of intervertebral disc degeneration (IVDD), so delay NPC senescence may be beneficial for mitigating IVDD. We studied the effect and mechanism of silent information regulator 2 homolog 3 (SIRT3) on NPC senescence in vivo and in vitro. First, we observed SIRT3 expression in normal and degenerated NPC with immunohistochemical and immunofluorescence staining. Second, using SIRT3 lentivirus transfection, reactive oxygen species probe, senescence-associated β-galactosidase staining, polymerase chain reaction, and western blot to observe the oxidative stress, senescence, and degeneration degree among groups. Subsequently, pretreatment with adenosine monophosphate-activated protein kinase (AMPK) agonists and inhibitors, observing oxidative stress, senescence, and degeneration degree among groups. Finally, the IVDD model was constructed and divided into Ctrl, Vehicle, LV-shSIRT3, and LV-SIRT3 groups. X-ray and magnetic resonance imaging scans were performed on rat's tails after 1 week; hematoxylin and eosin and safranin-O staining were used to evaluate the degree of IVDD; immunofluorescence staining was used to observe SIRT3 expression; immunohistochemical staining was used to observe oxidative stress, senescence, and degeneration degree of NP. We found that SIRT3 expression is reduced in degenerated NP tissues but increased in H2 O2 -induced NPC. Moreover, SIRT3 upregulation decreased oxidative stress, delayed senescence, and degeneration of NPC. In addition, activation of the AMPK/PGC-1α pathway can partially mitigate the NPC oxidative stress, senescence, and degeneration caused by SIRT3 knockdown. The study in vivo revealed that local SIRT3 overexpression can significantly reduce oxidative stress and ECM degradation of NPC, delay NPC senescence, thereby mitigating IVDD. In summary, SIRT3 mediated by the AMPK/PGC-1α pathway mitigates IVDD by delaying oxidative stress-induced NPC senescence.

Protective effects of liquiritin on UVB-induced skin damage in SD rats

Overexposure to ultraviolet B (UVB) rays can cause damage to the skin. Liquiritin has a variety of pharmacological effects, such as anti-inflammatory and antioxidant. In the present study, the effect of liquiritin on UVB irradiated rat skin was investigated. Results showed that UVB irradiation caused erythema and wrinkles on the skin surface, as well as thickening and loss of elasticity of the epidermis and a significant increase in the level of ROS in the skin tissue. At the same time, western blot detected an increase in nuclear factor kappa-B (NF-κB) and matrix metalloproteinases (MMPs) and Elisa also detected an increase in pro-inflammatory factors. Therefore, we hypothesized that UVB irradiation-induced damage is associated with inflammation. Interestingly, application of liquiritin to exposed skin of rats reduced the increase in ROS, pro-inflammatory factors, and MMPs caused by UVB irradiation and increased the levels of Sirtuin3 (SIRT3) and Collagen α1. In addition, after intraperitoneal injection of the SIRT3 inhibitor 3-TYP in rats, the protective effect of liquiritin against UVB damage was found to be diminished. These results suggested that promotion of SIRT3 with liquiritin inhibits UVB-induced production of pro-inflammatory mediators, possibly acting through the SIRT3/ROS/NF-κB pathway. In conclusion, this study suggests that liquiritin is an effective drug candidate for the prevention of UVB damage.

Paricalcitol inhibits oxidative stress-induced cell senescence of the bile duct epithelium dependent on modulating Sirt1 pathway in cholestatic mice

BACKGROUND

Clinical studies indicate that vitamin D receptor (VDR) expression is reduced in primary biliary cirrhosis patient livers. However, the mechanism by which activated VDR effect cholestatic liver injury remains unclear.

METHODS

Mice were injected intraperitoneally with the VDR agonist paricalcitol or a vehicle 3 days prior to bile duct ligation (BDL) and for 5 or 28 days after surgery. The analyses of liver morphology and necrotic areas were based on H&E staining. Serum biochemical indicators of liver damage were analyzed by commercial kits. The mechanisms of paricalcitol on cholestatic liver injury were determined by Western blot analysis.

RESULTS

Paricalcitol ameliorated the BDL-induced liver damage in mice. Paricalcitol increased the proliferation of BECs to promote the repair of the bile duct. Paricalcitol also reduced the BDL-induced oxidative stress level in the mice. Mechanistic analysis revealed that paricalcitol decreased the number of SA-β-gal-positive cells and downregulated the expression of p53, p21 and p16 proteins which was associated with reducing oxidative stress. Additionally, paricalcitol exerted the inhibitory effect of cell senescence was through reducing DNA damage and promoting DNA repair. Interesting, we found that paricalcitol prevented the downregulation of oxidative stress-induced Sirt1 expression in the BDL mice and t-BHP-induced BECs models. Moreover, paricalcitol suppressed cell senescence through a Sirt1-dependent pathway. These results were confirmed by antioxidant ALCAR and the Sirt1 inhibitor EX-527.

CONCLUSION

Paricalcitol alleviated cholestatic liver injury through promoting the repair of damaged bile ducts and reducing oxidative stress-induced cell senescence of the bile duct via modulating Sirt1 pathway.

Cytoprotective Potential of Fucoxanthin in Oxidative Stress-Induced Age-Related Macular Degeneration and Retinal Pigment Epithelial Cell Senescence In Vivo and In Vitro

Oxidative stress is identified as a major inducer of retinal pigment epithelium (RPE) cell dysregulation and is associated with age-related macular degeneration (AMD). The protection of RPE disorders plays an essential role in the pathological progress of retinal degeneration diseases. The pharmacological functions of fucoxanthin, a characteristic carotenoid, including anti-inflammatory and antioxidant properties, may ameliorate an outstanding bioactivity against premature senescence and cellular dysfunction. This study demonstrates that fucoxanthin protects RPE cells from oxidative stress-induced premature senescence and decreased photoreceptor cell loss in a sodium iodate-induced AMD animal model. Similarly, oxidative stress induced by hydrogen peroxide, nuclear phosphorylated histone (γH2AX) deposition and premature senescence-associated β-galactosidase staining were inhibited by fucoxanthin pretreatment in a human RPE cell line, ARPE-19 cells. Results reveal that fucoxanthin treatment significantly inhibited reactive oxygen species (ROS) generation, reduced malondialdehyde (MDA) concentrations and increased the mitochondrial metabolic rate in oxidative stress-induced RPE cell damage. Moreover, atrophy of apical microvilli was inhibited in cells treated with fucoxanthin after oxidative stress. During aging, the RPE undergoes well-characterized pathological changes, including amyloid beta (Aβ) deposition, beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1) expression and tight junction disruption, which were also reduced in fucoxanthin-treated groups by immunofluorescence. Altogether, pretreatment with fucoxanthin may protect against premature senescence and cellular dysfunction in retinal cells by oxidative stress in experimental AMD animal and human RPE cell models.

Velvet antler polypeptide prevents the disruption of hepatic tight junctions via inhibiting oxidative stress in cholestatic mice and liver cell lines

The present study aims to examine the protective effects and mechanism of a velvet antler polypeptide (VAP) against lithocholic acid (LCA)-induced cholestatic liver injury in mice. A 7.0 kDa VAP was orally administered at doses of 10 and 20 mg kg-1 day-1. Hematoxylin and eosin (H&E) staining of the liver showed that VAP7.0 reduced LCA-induced infiltration of inflammatory cells and areas of necrotic hepatocytes. In addition, VAP7.0 greatly reduced the levels of alanine aminotransferase (ALT), total bile acid (TBA) and total bilirubin (TBIL) in LCA mouse serum and prolonged the survival time of mice with LCA. VAP7.0 reduced the production of reactive oxygen species (ROS), decreased malondialdehyde (MDA) and increased the superoxide dismutase (SOD) levels in LCA mice. VAP7.0 also reduced OGG1 expression, which is a biochemical indicator of oxidative stress. Mechanistic analysis revealed that VAP7.0 significantly inhibited LCA-induced disruption of tight junction integrity, as determined by observing the morphology of the bile canaliculus, and this finding was confirmed by observation of the bile canalicular structure and tight junction proteins Occludin and ZO-1 expression. Moreover, we also found that VAP7.0 maintained the stability of hepatic paracellular permeability, as determined by Evans blue dye assays and horseradish peroxidase (HRP) tracer distribution through inhibiting the activation of the PI3K pathway in LCA mouse livers. In addition, VAP7.0 ameliorated H2O2-induced barrier dysfunction and tight junction disruption via inhibiting the PI3K activity in human HepG2 and SMMC7721 cells, which was confirmed by the PI3K activator 740Y-P. H2O2 disturbed the localization of the tight junction proteins ZO-1 and Occludin, resulting in the transfer of these proteins from the membrane to the cytoplasm of cells, whereas pretreatment of cells with VAP7.0 prevented the disruption of the localization of these proteins, as determined by immunofluorescence staining and western blot analysis. These results demonstrate that VAP7.0 reduces liver injury by inhibiting oxidative stress and maintains the stability of hepatic tight junctions via suppressing the activation of the intracellular signaling molecule PI3K in LCA mice and hepatocellular carcinoma cells.

Ameliorative effects and mechanism of crocetin in arsenic trioxide‑induced cardiotoxicity in rats

Arsenic trioxide (ATO) is commonly used to treat patients with acute promyelocytic leukemia since it was authorized by the U.S. Food and Drug Administration in the 1970s, but its applicability has been limited by its cardiotoxic effects. Therefore, the aim of the present study was to investigate the cardioprotective effects and underlying mechanism of crocetin (CRT), the critical ingredient of saffron. Sprague-Dawley rats were then randomly divided into four groups (n=10/group): i) Control group; ii) ATO group, iii) CRT-low (20 mg/kg) group; and iv) CRT-high (40 mg/kg) group. Rats in the Control and ATO groups were intraperitoneally injected with equal volumes of 0.9% sodium chloride solution, and CRT groups were administered with either 20 and 40 mg/kg CRT. Following 6 h, all groups except the Control group were intraperitoneally injected with 5 mg/kg ATO over 10 days. Cardiotoxicity was indicated by changes in electrocardiographic (ECG) patterns, morphology and marker enzymes. Histomorphological changes in the heart tissue were observed by pathological staining. The levels of superoxide dismutase, glutathione peroxidase, malondialdehyde and catalase in the serum were analyzed using colometric commercial assay kits, and the levels of reactive oxygen species in the heart tissue were detected using the fluorescent probe dihydroethidium. The expression levels of inflammatory factors and activities of apoptosis-related proteins were analyzed using immunohistochemistry. The protein expression levels of silent information regulator of transcription 1 were measured using western blotting. Cardiotoxicity was induced in male Sprague-Dawley rats with ATO (5 mg/kg). CRT (20 and 40 mg/kg) and ATO were co-administered to evaluate possible cardioprotective effects. CRT significantly reduced the heart rate and J-point elevation induced by ATO in rats. Histological changes were evaluated via hematoxylin and eosin staining. CRT decreased the levels of creatine kinase and lactate dehydrogenase, increased the activities of superoxide dismutase, glutathione-peroxidase and catalase, and decreased the levels of malondialdehyde and reactive oxygen species. Moreover, CRT downregulated the expression levels of the pro-inflammatory factors IL-1, TNF-α, IL-6, Bax and p65, as well as increased the expression of Bcl-2. It was also identified that CRT enhanced silent information regulator of transcription 1 protein expression. Thus, the present study demonstrated that CRT treatment effectively ameliorated ATO-induced cardiotoxicity. The protective effects of CRT can be attributed to the inhibition of oxidative stress, inflammation and apoptosis. Therefore, CRT represents a promising therapeutic method for improving the cardiotoxic side effects caused by ATO treatment, and additional clinical applications are possible, but warrant further investigation.

Inhalation of molecular hydrogen increases breath acetone excretion during submaximal exercise: a randomized, single-blinded, placebo-controlled study

Aerobic exercise is widely accepted as a beneficial option for reducing fat in humans. Recently, it has been suggested that molecular hydrogen (H₂) augments mitochondrial oxidative phosphorylation. Therefore, the hypothesis that inhaling H₂ could facilitate lipid metabolism during aerobic exercise was investigated in the current study by measuring the breath acetone levels, which could be used as non-invasive indicators of lipid metabolism. This study aimed to investigate the effect of inhaling H₂ on breath acetone output during submaximal exercise using a randomized, single-blinded, placebo-controlled, and cross-over experimental design. After taking a 20-minute baseline measurement, breath acetone levels were measured in ten male subjects who performed a 60% peak oxygen uptake-intensity cycling exercise for 20 minutes while inhaling either 1% H₂ or a control gas. In another experiment, six male subjects remained in a sitting position for 45 minutes while inhaling either 1% H₂ or a control gas. H₂ significantly augmented breath acetone and enhanced oxygen uptake during exercise (P < 0.01). However, it did not significantly change oxidative stress or antioxidant activity responses to exercise, nor did it significantly alter the breath acetone or oxygen uptake during prolonged resting states. These results suggest that inhaling H₂ gas promotes an exercise-induced increase in hepatic lipid metabolism. The study was approved by the Ethical Committee of Chubu University, Japan (approved No. 260086-2) on March 29, 2018.

Bakuchiol Alleviates Hyperglycemia-Induced Diabetic Cardiomyopathy by Reducing Myocardial Oxidative Stress via Activating the SIRT1/Nrf2 Signaling Pathway

Bakuchiol (BAK), a monoterpene phenol reported to have exerted a variety of pharmacological effects, has been related to multiple diseases, including myocardial ischemia reperfusion injury, pressure overload-induced cardiac hypertrophy, diabetes, liver fibrosis, and cancer. However, the effects of BAK on hyperglycemia-caused diabetic cardiomyopathy and its underlying mechanisms remain unclear. In this study, streptozotocin-induced mouse model and high-glucose-treated cell model were conducted to investigate the protective roles of BAK on diabetic cardiomyopathy, in either the presence or absence of SIRT1-specific inhibitor EX527, SIRT1 siRNA, or Nrf2 siRNA. Our data demonstrated for the first time that BAK could significantly abate diabetic cardiomyopathy by alleviating the cardiac dysfunction, ameliorating the myocardial fibrosis, mitigating the cardiac hypertrophy, and reducing the cardiomyocyte apoptosis. Furthermore, BAK achieved its antifibrotic and antihypertrophic actions by inhibiting the TGF-β1/Smad3 pathway, as well as decreasing the expressions of fibrosis- and hypertrophy-related markers. Intriguingly, these above effects of BAK were largely attributed to the remarkable activation of SIRT1/Nrf2 signaling, which eventually strengthened cardiac antioxidative capacity by elevating the antioxidant production and reducing the reactive oxygen species generation. However, all the beneficial results were markedly abolished with the administration of EX527, SIRT1 siRNA, or Nrf2 siRNA. In summary, these novel findings indicate that BAK exhibits its therapeutic properties against hyperglycemia-caused diabetic cardiomyopathy by attenuating myocardial oxidative damage via activating the SIRT1/Nrf2 signaling.

The dominant model analysis of Sirt3 genetic variants is associated with susceptibility to tuberculosis in a Chinese Han population

Tuberculosis (TB) is a complex infectious disease caused by the pathogen Mycobacterium tuberculosis (Mtb) which has coexisted with humanity since the Neolithic. Recent research indicated that SIRT3 plays a pivotal role in promoting the antimycobacterial response of mitochondria and autophagy during Mtb infection. A case-control study comprised 900 TB patients and 1534 healthy controls who were retrospectively enrolled to assess the association between Sirt3 gene polymorphisms and TB susceptibility. In total, five single-nucleotide polymorphisms (SNPs) (rs511744, rs3782118, rs7104764, rs536715 and rs28365927) were selected through database 1000 Genomes Project and offline software Haploview V4.2 and genotyped by a customized 2 × 48-Plex SNPscan™ Kit. Our results suggested that the minor allele genotypes (A carriers) of rs3782118 confers the decreased risk of TB susceptibility (p_Bonferroni = 0.032), and a similar but more significant effect was observed under the dominant model analysis (OR 0.787, 95% CI 0.666-0.931, p_Bonferroni = 0.026). Haplotype analysis showed that haplotype AGAAG (rs511744/rs3782118/rs7104764/rs536715/rs28365927) was associated with an increased risk of TB (p = 0.023, OR 1.159, 95% CI 1.019-1.317). In stratification analysis, we found that rs3782118 was associated with decreased risk of TB in female subgroup under the dominant model analysis (p_Bonferroni = 0.016, OR 0.678, 95% CI 0.523-0.878). Moreover, functional annotations for three loci (rs7930823, rs3782116 and rs3782115) which are strongly linked to rs3782118 indicated that they may be responsible for the changes in some motifs. In conclusion, our study suggested that the SNP rs3782118 was associated with a lower susceptibility to TB, especially under the dominant model analysis and that the haplotype AGAAG (containing the major allele G of rs3782118) was associated with an increased risk of TB. Further independent cohort studies are necessary to validate the protective effect of Sirt3 genetic variants on the risk of TB.