Melatonin attenuates sepsis-induced acute kidney injury by promoting mitophagy through SIRT3-mediated TFAM deacetylation

Role of mitophagy in spinal cord ischemia-reperfusion injury

Spinal cord ischemia-reperfusion injury, a severe form of spinal cord damage, can lead to sensory and motor dysfunction. This injury often occurs after traumatic events, spinal cord surgeries, or thoracoabdominal aortic surgeries. The unpredictable nature of this condition, combined with limited treatment options, poses a significant burden on patients, their families, and society. Spinal cord ischemia-reperfusion injury leads to reduced neuronal regenerative capacity and complex pathological processes. In contrast, mitophagy is crucial for degrading damaged mitochondria, thereby supporting neuronal metabolism and energy supply. However, while moderate mitophagy can be beneficial in the context of spinal cord ischemia-reperfusion injury, excessive mitophagy may be detrimental. Therefore, this review aims to investigate the potential mechanisms and regulators of mitophagy involved in the pathological processes of spinal cord ischemia-reperfusion injury. The goal is to provide a comprehensive understanding of recent advancements in mitophagy related to spinal cord ischemia-reperfusion injury and clarify its potential clinical applications.

Dendrobine attenuates sepsis-associated acute kidney injury by promoting PINK1/PARKIN-mediated mitophagy

Sepsis-associated acute kidney injury (SA-AKI) is a severe condition with high mortality rates and a lack of specific treatments. Dendrobine (DEN) has shown diverse pharmacological effects across different diseases. Nonetheless, its impact on SA-AKI remains unexplored. This study aimed to investigate DEN's therapeutic potential in SA-AKI and elucidate its mechanism of action. In vivo, SA-AKI models were induced through cecal ligation and puncture or lipopolysaccharide (LPS) administration, while in vitro model was established using LPS-stimulated HK-2 cells. We found that pre-treatment with DEN reduced levels of inflammation-related cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), and improved kidney function in SA-AKI both in vitro and in vivo. RNA-seq analysis unveiled the critical role of mitophagy in DEN treatment for SA-AKI. We observed an initial increase in mitophagy-related proteins such as PINK1, PARKIN, and LC3B/A, peaking at 8 h post-LPS stimulation, followed by a subsequent decline. Additionally, we demonstrated that DEN upregulated the expression of mitophagy-associated proteins in both in vitro and in vivo SA-AKI models. Notably, we found that carbonyl cyanide 3-chlorophenylhydrazone (CCCP) increased LC3B/A levels in DEN treatment for SA-AKI, whereas Mdivi-1 counteracted the effect of DEN on PINK1, PARKIN, and LC3B/A. These findings demonstrated that DEN enhances mitophagy through the activation of PINK1/PARKIN-mediated pathways, thus mitigating SA-AKI.

Urolithin A alleviates radiation pneumonitis by activating PINK1/PRKN-mediated Mitophagy

BACKGROUND

Radiation pneumonitis (RP) is a common and severe complication of radiotherapy, whose pathogenesis involves complex inflammatory responses and cellular damage. Despite its clinical significance, effective treatments remain limited. This study investigates the role of radiation-induced PINK1/PRKN-mediated mitophagy and type I interferon responses in RP and evaluates the therapeutic potential of Urolithin A (UA) in regulating inflammation through mitophagy activation.

METHODS

We established RP mouse models (20 Gy thoracic irradiation) and radiation-induced BEAS-2B cell models (6 Gy). We systematically investigated mitochondrial damage, mtRNA release, RIG-I/MDA5-MAVS pathway activation, and PINK1/PRKN-mediated mitophagy changes. Moreover, the effects of UA and the mitophagy inhibitor Mdivi-1 on inflammation and lung injury were analyzed.

RESULTS

Radiation significantly caused mitochondrial damage in lung tissues, inducing mtRNA release and RIG-I/MDA5-MAVS-mediated type I interferon response. PINK1/PRKN-mediated mitophagy was significantly enhanced, clearing damaged mitochondria and reducing cytosolic mtRNA release, thereby suppressing inflammation. Pharmacological activation of mitophagy with UA markedly improved lung pathology, reduced inflammatory cytokine levels, and inhibited excessive activation of the RIG-I/MDA5-MAVS pathway. Conversely, the knockdown of PINK1 or PRKN weakened the protective effects of UA. Both in vitro and in vivo, UA reduced radiation-induced inflammation and improved lung tissue structure and function through mitophagy.

CONCLUSIONS

Radiation-induced mtRNA release activates the RIG-I/MDA5-MAVS-mediated type I interferon response, driving inflammation in RP. PINK1/PRKN-mediated mitophagy significantly alleviates inflammation by reducing cytosolic mtRNA release. As a mitophagy inducer, UA demonstrates therapeutic potential for RP, providing a new direction for the development of anti-inflammatory strategies.

Mitochondrial electron transport chain disruption and oxidative stress in lipopolysaccharide-induced cardiac dysfunction in rats and mice

Sepsis, characterized by severe systemic inflammation and an excessive immune response to infection, is frequently triggered by bacterial endotoxins like lipopolysaccharide (LPS) from Gram-negative bacteria. Moreover, sepsis-induced cardiac dysfunction remains a leading cause of mortality. This study aims to elucidate the effects of LPS-induced cardiac injury on mitochondrial damage, oxidative stress, and subsequent cardiac dysfunction. LPS injections (in rats and mice) for three days (1.5 mg/kg) impacted the body weight and increased cardiac TNF-α. Additionally, it decreased mitochondrial complexes I and II activities while complexes III and IV remained unaffected. Disturbed in mitochondrial electron transport chain leads to an increase in reactive oxygen species (ROS). Indeed, LPS treatment significantly increased mitochondrial hydrogen peroxide production, reduced the activity of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase activity. This was accompanied by decreased mitochondrial and cytosolic sulfhydryl proteins and parallel increased cellular lipid peroxidation in the presence or absence of Fe2+. LPS-treated samples had increased glutathione s-transferase activity, which may be an attempt of the cell to remove toxic lipid peroxidation products. In a more acute Langendorff-perfused rat hearts, LPS infusion (0.5 μg/mL) induced a significant elevation in left ventricular end-diastolic pressure and a decrease in left ventricular developed pressure. These findings elucidate the harmful mitochondrial and oxidative effects of LPS in cardiac tissue and could help the development of targeted therapies to mitigate the adverse effects of sepsis-induced cardiac dysfunction.

Melatonin Interplay in Physiology and Disease-The Fountain of Eternal Youth Revisited

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone associated with the regulation of biological rhythms. The indoleamine is secreted by the pineal gland during the night, following a circadian rhythm. The highest plasmatic levels are reached during the night, whereas the lowest levels are achieved during the day. In addition to the pineal gland, other organs and tissues also produce melatonin, like, for example, the retina, Harderian glands, gut, ovaries, testes, skin, leukocytes, or bone marrow. The list of organs is extensive, including the cerebellum, airway epithelium, liver, kidney, adrenals, thymus, thyroid, pancreas, carotid body, placenta, and endometrium. At all these locations, the availability of melatonin is intended for local use. Interestingly, a decline of the circadian amplitude of the melatonin secretion occurs in old subjects in comparison to that found in younger subjects. Moreover, genetic and environmental factors are the primary causes of diseases, and oxidative stress is a key contributor to most pathologies. Numerous studies exist that show interesting effects of melatonin in different models of disease. Impairment in its secretion might have deleterious consequences for cellular physiology. In this regard, melatonin is a natural compound that is a carrier of a not yet completely known potential that deserves consideration. Thus, melatonin has emerged as a helpful ally that could be considered as a guard with powerful tools to orchestrate homeostasis in the body, majorly based on its antioxidant effects. In this review, we provide an overview of the widespread actions of melatonin against diseases preferentially affecting the elderly.

Huangqi and Danshen improve the chronic nephrotoxicity of cyclosporin A by regulating lipid metabolism

BACKGROUND

The clinical application of cyclosporine A (CsA) is limited due to nephrotoxicity. Lipid metabolism disorders play important roles in renal injury, but their role in CsA nephrotoxicity is not yet clear. Huangqi (Astragalus mongholicus Bunge) and Danshen (Salvia miltiorrhiza Bunge) (HD) play roles in ameliorating the nephrotoxicity of CsA, but their mechanisms still need to be fully clarified.

OBJECTIVE

This study innovatively aimed to analyse the coexpression of renal proteins and serum metabolites for the identification of key pathways and targets. This study provides novel insight into the mechanism by which HD ameliorates CsA-induced nephrotoxicity.

METHODS

We utilized HD to intervene in both in vivo and in vitro nephrotoxicity models induced by CsA. For the in vivo experiments, we constructed a coexpression network of renal proteins and serum metabolites, which was used to screen for key pathways. To validate these findings, we knocked down key proteins in vivo. For the in vitro studies, we employed MTT, Transwell, flow cytometry, and immunofluorescence assays to monitor the epithelial-mesenchymal transition (EMT) of HK-2 cells. Additionally, we used electron microscopy and Seahorse assays to examine the effects of HD on mitochondrial structure and function. Furthermore, we overexpressed Ppara to further confirm the mechanism by which HD improves renal function.

RESULTS

HD can improve renal pathological damage and function; regulate blood lipids, inflammation and oxidative stress indicators; and reduce apoptosis in renal tissues. Joint protein and metabolomics analyses revealed that two lipid metabolism-related pathways (the PPAR signalling pathway and linoleic acid metabolism pathway) were coenriched, involving six differential proteins (Cyp2e1, Cyp4a10, Gk, Lpl, Ppara, and Pck1) and two differentially abundant metabolites (alpha-Dimorphecolic acid and 12,13-EpOME). Western blot was used to verify differentially expressed proteins. HD improved mitochondrial damage and lipid accumulation, as demonstrated by transmission electron microscopy (TEM) analysis and Oil Red O staining. Knockdown of the key protein Ppara affected the expression of ACOX1 and exacerbated RF. In vitro verification demonstrated that HD significantly inhibited CsA-induced EMT in HK-2 cells and improved mitochondrial structure and function. Ppara overexpression promoted HD-mediated regulation of mitochondrial function, reduced apoptosis, and improved HK-2 RF.

CONCLUSION

HD can ameliorate CsA nephrotoxicity through renal protein-serum metabolism coexpression, the PPAR signalling pathway, and linoleic acid metabolism. HD-induced upregulation of Ppara to regulate lipid metabolism, improve mitochondrial function and reduce apoptosis are important mechanisms. The Ppara/ACOX1/TGF-β1 axis may play an important role in this process. These findings offer potential targets for the future development of therapeutic strategies and novel drugs.

SIRT3 mitigates dry eye disease through the activation of autophagy by deacetylation of FOXO1

Dry eye disease (DED) is a complex ocular condition characterized by oxidative stress, inflammation, and apoptosis. An increasing number of studies suggest that Sirtuin3 (SIRT3), a mitochondrial deacetylase, may offer protection against related pathologies. Despite these indications, the precise function and underlying mechanisms of SIRT3 in the context of DED have not been fully elucidated. Here, we observed a decline in SIRT3 expression in human corneal epithelial cells (HCE-Ts) and the corneal conjunctiva of mice as the disease advanced. Overexpression of SIRT3 in HCE-Ts reduced the accumulation of reactive oxygen species (ROS), inflammatory cytokines, and the rate of apoptosis, while its inhibition had the opposite effect. Importantly, the function of SIRT3 was exerted through the enhancement of autophagic flux. Further studies have shown that chloroquine-induced inhibition of autophagy neutralized the beneficial effects of SIRT3. In our in vivo experiments, the application of eye drops containing a SIRT3 agonist ameliorated the symptoms of DED and increased corneal autophagy in mice. Mechanistically, our study identified that the deacetylation and nuclear translocation of FOXO1 (Forkhead box O1) are pivotal for the SIRT3-mediated enhancement of autophagic flux. These findings posit that SIRT3 as an encouraging therapeutic target for DED, offering new insights into the disease's underlying mechanisms.

Mitophagy Protects Against Cisplatin-Induced Injury in Granulosa Cells

Cisplatin, a widely used chemotherapeutic agent, is known to induce premature ovarian insufficiency (POI) and infertility in women of reproductive age. Among the contributing factors, cisplatin-induced apoptosis of ovarian granulosa cells is considered a primary driver of ovarian dysfunction; however, the underlying mechanisms remain incompletely understood. In this study, we investigated the cytotoxicity of cisplatin on the granulosa cell line KGN in vitro and explored the associated mechanisms. Our results demonstrate that cisplatin induces KGN cell apoptosis in a dose-dependent manner and impairs mitochondrial function, as evidenced by excessive ROS production, membrane potential collapse, and reduced ATP synthesis. Mitophagy, a key cellular self-protection mechanism that selectively removes damaged mitochondria, was activated following cisplatin treatment, mitigating its detrimental effects on KGN cells. Activation of mitophagy with urolithin A (UA) ameliorated cisplatin-induced mitochondrial dysfunction and apoptosis, whereas inhibition of mitophagy with cyclosporine A (CsA) exacerbated these effects. Furthermore, pretreatment with the clinical drug melatonin significantly enhanced mitophagy, effectively attenuating cisplatin-induced apoptosis in KGN cells. This study proposes a novel therapeutic strategy for patients undergoing tumor chemotherapy, aiming to preserve treatment efficacy while reducing the adverse effects of chemotherapeutic agents on ovarian function, thereby improving patients' quality of life.

TFAM Deficiency Triggers mtDNA Leakage and cGAS-STING-Mediated Intestinal Ischemia-Reperfusion Injury

Intestinal Ischemia-Reperfusion (IIR) injury is a common clinical pathophysiological condition, yet the complex molecular mechanisms underlying its pathology remain incompletely understood. This study aims to explore the precise molecular mechanisms of IIR injury, with a focus on the role of the cGAS-STING signaling pathway. Using a mouse IIR model and hypoxia/reoxygenation (HR) model in HT-29 cells and small intestinal organoids, we observed that IIR significantly induces oxidative stress and activates the cGAS-STING pathway, which is associated with exacerbated small intestinal tissue damage and enhanced inflammatory responses. Further investigation revealed that mitochondrial DNA (mtDNA) leakage is a critical trigger for the activation of the cGAS-STING pathway. The introduction of exogenous mtDNA into cells activated the STING pathway and exacerbated cellular damage. In contrast, the depletion of intracellular mtDNA effectively suppressed HR-induced activation of the cGAS-STING pathway. Mechanistically, we found that IIR downregulates mitochondrial transcription factor A (TFAM), which subsequently affects mtDNA stability, promoting the release of mtDNA into the cytoplasm and triggering the cGAS-STING pathway. Overexpression of TFAM stabilized mtDNA, reduced the accumulation of cytoplasmic mtDNA, inhibited cGAS-STING pathway activation, and alleviated cellular damage. Moreover, STING-deficient mice exhibited reduced inflammation, less tissue damage, and improved survival rates following IIR, highlighting the critical role of the STING pathway in IIR-induced injury. Our findings elucidate the close association between oxidative stress, inflammation, and cGAS-STING pathway activation in IIR. mtDNA leakage and TFAM downregulation are key mechanisms driving this activation. Importantly, TFAM plays a crucial role in stabilizing mtDNA and reducing mtDNA leakage during IIR. These results not only deepen our understanding of the molecular pathogenesis of IIR injury but also provide potential therapeutic strategies targeting the cGAS-STING pathway for treating IIR-related diseases.

CD177+ neutrophils exacerbate septic lung injury via the NETs/AIM2 pathway: An experimental and bioinformatics study

BACKGROUND

Acute lung injury (ALI) is one of the most common complications of sepsis. However, the underlying mechanisms and effective treatment strategies remain poorly understood. Immune cells are crucial in sepsis-induced lung injury, yet the heterogeneity of the immune cell populations involved in this context is not well characterized.

METHODS

This study established a Cecal Ligation and Puncture (CLP) mouse model and employed single-cell sequencing along with molecular biology experimental methods to identify the primary functional subgroups of immune cells associated with sepsis-induced ALI, thereby elucidating the key mechanisms related to sepsis-induced ALI.

RESULTS

Our analysis revealed that, in comparison to normal mice, the top 100 differentially expressed genes (DEGs) in septic lung tissue during the acute phase predominantly originate from neutrophils. Cd177 antigen (Cd177)+ neutrophils represent the predominant subpopulation of neutrophils in septic lung tissue. These cells exhibit unique pro-inflammatory and oxidative stress characteristics, and they are capable of producing excessive neutrophil extracellular traps (NETs). NETs can aggravate ALI by activating Absent in Melanoma 2 (AIM2) inflammasome. Furthermore, we discovered that melatonin could effectively inhibit the infiltration of Cd177+ neutrophils in septic lung tissue, reduce the expression levels of NETs, and diminish the activation of AIM2, thereby improving lung injury.

CONCLUSION

Our research provides novel insights and potential therapeutic targets for the treatment of sepsis-induced ALI.

Integrating network pharmacology, molecular docking, and animal studies to investigate the protective effect of astragalus polysaccharide on fluoride-induced renal injury in rats

Fluoride is an essential trace element required for normal physiological functions and holds significant importance for human health. However, excessive fluoride intake can lead to renal damage, for which effective prevention and therapeutic strategies remain scarce. Astragalus polysaccharide (APS), a major bioactive component of the traditional Chinese herb Astragalus membranaceus, possesses pharmacological properties including anti-inflammatory, antiviral, and antioxidant activities. In this study, we investigated the protective effects of APS against fluoride-induced renal injury in vivo experiment. Additionally, network pharmacology and molecular docking techniques were employed to predict its potential mechanisms of action, while the protein expression levels of key target molecules were validated. The results demonstrated that APS intervention significantly alleviated renal injury and oxidative stress induced by sodium fluoride (NaF) in rats. Key targets involved in the amelioration of fluoride-induced renal damage by APS included STAT3, Caspase-3, JUN, MMP1, and PTGS2. Molecular docking analysis revealed high-affinity binding between APS and these core targets. Immunohistochemical and Western blot analysis further confirmed that APS suppressed the expression of pro-apoptotic proteins STAT3, Caspase-3, JUN, and MMP1 while enhancing the expression of the anti-apoptotic protein PTGS2. Overall, our findings suggest that APS alleviates fluoride-induced renal injury by modulating multiple targets, with the potential mechanism linked to the regulation of apoptotic processes. This study provides a theoretical basis for the prevention and treatment of fluoride toxicity.

Dietary phytosterol supplementation mitigates renal fibrosis via activating mitophagy and modulating the gut microbiota

Chronic kidney disease (CKD) poses a significant global health challenge, primarily driven by renal fibrosis, with limited treatment options. Addressing this condition necessitates either targeted medical treatments or dietary interventions. Phytosterols (PS) are cholesterol-like bioactive compounds in various plant-based foods with antioxidant and anti-inflammatory effects. A CKD mouse model was established using folic acid (FA) and treated with dietary supplements of two PS, stigmasterol (Stig) and β-sitosterol (β-Sito). The effects and mechanisms of PS were investigated through biochemical indices, pathology, transcriptomics, and 16S rDNA sequencing. The results indicated that high-dose PS are more effective than low-dose PS and Losartan potassium (LP) in reducing renal fibrosis, restoring function, and modulating oxidative stress and inflammation, with no significant differences between high-dose Stig and β-Sito treatments. Gene Ontology (GO) enrichment analysis revealed that PS were significantly enriched in pathways related to the mitochondrial outer membrane, ubiquitin-protein ligase binding, and other cellular components and molecular processes. PS reduced the expression of TGF-β/Smad and cGAS/Sting1/TBK1 and activated PINK1/Parkin pathway proteins, thereby mitigating renal fibrosis in mice. CKD is often associated with imbalanced gut microbiota and compromised intestinal barriers. Our observations indicated that PS restored the intestinal barrier, altered the composition of the gut microbiota, and improved renal function in CKD mice. The present findings indicate that both Stig and β-Sito activate mitophagy via the PINK1/Parkin pathway and modulate the gut microbiota, thereby alleviating renal fibrosis. The findings provide solid and significant implications for developing effective application of PS supplementation in the management of CKD, presenting novel concepts and approaches for research and clinical treatment.

Network pharmacology, molecular docking, and experimental verification reveal the mechanism of Yi-Shen-Hua-Shi granules treating acute kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

Yi-Shen-Hua-Shi granules (YSHSG) have been shown to improve kidney function in various renal disorders, which are characterized by the sudden decline and impairment of kidney function.

AIM OF THE STUDY

To investigate the precise mechanisms and targets of YSHSG in combating sepsis-induced AKI.

MATERIALS AND METHODS

Through network pharmacology, the active ingredients, main target proteins, and related signaling pathways of YSHSG in the treatment of sepsis-induced AKI were predicted. The AKI model was induced by sepsis using the cecal ligation and puncture (CLP) technique. Prior to the operation, YSHSG was administered intragastrically once daily for 1 week. Blood and kidney tissues were collected 48 h post-CLP to verify the network pharmacology analysis.

RESULTS

The core target proteins of YSHSG in the treatment of sepsis-induced AKI include AKT1, JUN, IL6, PTGS2, NFKBIA, MAPK3, Caspase-3 and MMP9, which were further confirmed by molecular docking. Pathway analyses such as Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) show that YSHSG plays a role in protecting the kidneys from sepsis-induced AKI through the PI3K/AKT, TNF, and IL17 signaling pathways. These findings were validated using qPCR and western blotting. In vivo experiments demonstrated that YSHSG inhibits the activation of TNF and IL17 signaling pathways while protecting against deactivation of the PI3K/AKT signaling pathway in sepsis-induced AKI. YSHSG also exhibits an effect on attenuating inflammation response and pyroptosis processes associated with the PI3K/AKT, TNF, and IL17 signaling pathways.

CONCLUSION

YSHSG mitigated sepsis-induced AKI by influencing the PI3K/AKT, TNF, and IL17 signaling pathways associated with inflammation and pyroptosis.

Sirt3 Rescues Porphyromonas gingivalis-Impaired Cementogenesis via SOD2 Deacetylation

The keystone pathogen Porphyromonas gingivalis (P.g.) is responsible for cementum resorption in periodontitis; however, the mechanism involved in it remains unclear. Sirtuin 3 (Sirt3) is a NAD+-dependent protein deacetylase contributing to mitochondrial homeostasis and various cell functions. In this study, the expression of Sirt3 in cementoblasts was found to be increased during cementoblast mineralisation and cementum development, while it decreased gradually under P.g. infection in a multiplicity of infection-dependent manner. Compared with wild type mice, the Sirt3 knockout mice showed less cellular cementum and lower mineralisation capacity with decreased expression of Runx2 and OCN in cementoblasts. Sirt3 inhibition by 3-TYP or Sirt3 silencing by lentivirus infection both confirmed the impaired cementogenesis. Conversely, honokiol (HKL) was simulated to bind Sirt3 and was applied to activate Sirt3 in cementoblasts. HKL-mediated Sirt3 activation facilitated cementoblast mineralisation and rescued P.g.-suppressed cementoblast mineralisation markedly. Superoxide dismutase 2 (SOD2), the downstream molecule of Sirt3, showed a similar expression pattern to Sirt3 under different conditions. Silencing of SOD2 was demonstrated to restrain cementoblast mineralisation. The pan acetylation was detected to decrease under Sirt3-upregulating conditions and increase under Sirt3-downregulating conditions. The binding of Sirt3 and SOD2 in cementoblasts was also verified. Furthermore, SOD2 acetylation and specific SOD2-K68 acetylation were found to be upregulated under P.g. or Sirt3 silencing conditions and downregulated by HKL stimulation. Moreover, K68Q mutation simulating acetylation decreased cementoblast mineralisation, while K68R mutation simulating deacetylation increased it. Altogether, Sirt3 deacetylates SOD2 via K68 to orchestrate P.g.-perturbed cementogenesis, and HKL is a Sirt3-targeted treatment candidate.

The Clinical Role of SIRT-3 in the Acute Rejection Process of Kidney Transplantation and Its Effects on Graft Outcomes: Evaluation of Biomarker Potential

Background and Objectives: The aim of this study was to investigate the changes in the SIRT family, the effects of sirtuins on kidney graft function, and their potential as biomarkers in patients who develop rejection after kidney transplantation. Materials and Methods: Blood samples were collected from 45 kidney transplant patients before and after rejection. Some of these patients experienced T-cell-mediated early rejection (TCMR), while others presented antibody-mediated late rejection (ABMR). The mRNA expression levels of SIRT-1, SIRT-3, and SIRT-7 were measured via real-time PCR, while the protein levels of SIRT-1, SIRT-2, SIRT-3, SIRT-5, and SIRT-7 were assessed using ELISA. Patients were grouped based on rejection type and histological characteristics. Statistical analyses were performed using SPSS software (V23). Results: The mean age of the patient group was 42.22, while the control group had a mean age of 35.23 (p = 0.002). SIRT-1, SIRT-3, and SIRT-7 levels were significantly higher in patients with rejection (p < 0.001). In patients with late-stage rejection, SIRT-3 was found to be associated with interstitial fibrosis and C4d accumulation. SIRT-7 levels showed a weak correlation with potassium levels (p = 0.014). Conclusions: Our findings demonstrate significant changes in the SIRT family during both early- and late-stage rejection processes. Particularly, the role of SIRT-3 in the late stage is highlighted, suggesting the potential use of this gene as a biomarker for managing rejection processes. These findings could provide valuable insights for developing treatment strategies in organ transplantation.

Enhanced SIRT3 expression restores mitochondrial quality control mechanism to reverse osteogenic impairment in type 2 diabetes mellitus

Osteoporosis represents a prevalent and debilitating comorbidity in patients diagnosed with type 2 diabetes mellitus (T2DM), which is characterized by suppressed osteoblast function and disrupted bone microarchitecture. In this study, we utilized male C57BL/6 J mice to investigate the role of SIRT3 in T2DM. Decreased SIRT3 expression and impaired mitochondrial quality control mechanism are observed in both in vitro and in vivo models of T2DM. Mechanistically, SIRT3 suppression results in hyperacetylation of FOXO3, hindering the activation of the PINK1/PRKN mediated mitophagy pathway and resulting in accumulation of dysfunctional mitochondria. Genetical overexpression or pharmacological activation of SIRT3 restores deacetylation status of FOXO3, thus facilitating mitophagy and ameliorating osteogenic impairment in T2DM. Collectively, our findings highlight the fundamental regulatory function of SIRT3 in mitochondrial quality control, crucial for maintaining bone homeostasis in T2DM. These insights not only enhance our understanding of the molecular mechanisms underlying diabetic osteoporosis but also identify SIRT3 as a promising therapeutic target for diabetic osteoporosis.

Therapeutic effect of umbilical cord mesenchymal stem cells on renal ischemia-reperfusion injury

Acute kidney injury (AKI) is a growing global health issue with no effective treatments. This study evaluates the therapeutic effects of umbilical cord mesenchymal stem cells (UC-MSCs) on AKI caused by ischemia-reperfusion injury (IRI) in mice. Thirty mice were divided into a sham group, an IRI group, and an MSC-treated group. Renal function was assessed, and histological analysis, immunofluorescence, and real-time PCR were used to evaluate renal damage, inflammatory cell presence, and cytokine expression (TNF-α, IL-6, IL-10). Results showed that MSC treatment reduced renal damage, decreased pro-inflammatory cytokines (TNF-α, IL-6), increased anti-inflammatory IL-10, and promoted kidney repair by homing to injury sites. Thus, umbilical cord MSCs may mitigate AKI by reducing inflammation and enhancing renal repair.

Modulation of autophagy by melatonin and its receptors: implications in brain disorders

Autophagy plays a crucial role in maintaining neuronal homeostasis and function, and its disruption is linked to various brain diseases. Melatonin, an endogenous hormone that primarily acts through MT1 and MT2 receptors, regulates autophagy via multiple pathways. Growing evidence indicates that melatonin's ability to modulate autophagy provides therapeutic and preventive benefits in brain disorders, including neurodegenerative and affective diseases. In this review, we summarize the key mechanisms by which melatonin affects autophagy and explore its therapeutic potential in the treatment of brain disorders.

Oxymatrine alleviates ALD-induced cardiac hypertrophy by regulating autophagy via activation Nrf2/SIRT3 signaling pathway

BACKGROUND

Cardiac hypertrophy is a prevalent early pathological manifestation in various cardiovascular diseases, lacking effective interventions to impede its progression. Although oxymatrine (OMT) has shown potential benefits for cardiac function, its therapeutic efficacy and mechanism in cardiac hypertrophy remain incompletely understood. Notably, mitochondrial damage and dysregulated autophagy are pivotal pathogenic mechanisms in cardiac hypertrophy.

PURPOSE

We investigate the pharmacological characteristics and mechanism of OMT in mitochondrial function and autophagy in cardiac hypertrophy.

STUDY DESIGN AND METHODS

A murine model of cardiac hypertrophy was induced by aldosterone in combination with high-salt drinking water, while primary cardiomyocyte hypertrophy was induced by aldosterone in vitro. Cardiac hypertrophy was assessed using echocardiography and histopathological staining. Autophagosomes and mitochondrial morphology were visualized by transmission electron microscopy. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and adenosine triphosphate (ATP) were quantified using commercial kits. The binding affinity of OMT with Nrf2 was assessed through molecular docking. Furthermore, adenovirus, agonists, and inhibitors were employed to modulate Nrf2, followed by quantitative real-time polymerase chain reaction (qRT-PCR), immunoblotting, co-immunoprecipitation, chromatin immunoprecipitation, immunohistochemistry, and cellular thermal shift assay.

RESULTS

OMT effectively attenuated aldosterone-induced cardiac hypertrophy both in vivo and in vitro. OMT promoted the activation of Nrf2, leading to elevated SIRT3 expression and enhanced autophagolysosome fusion, thereby modulating mitophagy and improving mitochondrial function. Moreover, the cardioprotective effects of OMT were abolished upon silencing or inhibition of Nrf2. OMT binds to Nrf2, facilitating its dissociation and nuclear translocation.

CONCLUSION

OMT activates Nrf2, consequently enhancing SIRT3 transcription, restoring autophagic flux, and preserving mitochondrial integrity, thereby mitigating aldosterone-induced cardiac hypertrophy. In summary, our study is the first to discover and confirm that OMT can stabilize Nrf2, promoting its activation and subsequently up-regulating SIRT3, which in turn facilitates mitochondrial autophagy. Additionally, PARKIN appears to play a key role in SIRT3-mediated regulation of mitophagy, warranting further investigation.

Faecalibacterium prausnitzii Suppresses Mitophagy to Alleviate Muscle Atrophy in Chronic Renal Failure With Protein-Energy Wasting

Protein-energy wasting (PEW) facilitates major adverse clinical outcomes in chronic renal failure (CRF), with current therapies not suitable for all patients. Faecalibacterium prausnitzii (F. prausnitzii) can alleviate chronic kidney disease, with unclear effects and mechanisms on CRF with PEW. The CRF rat model was constructed by adenine administration, and PEW was induced by a 4% casein diet. The serum creatinine (SCR), urinary protein (UPR), and blood urea nitrogen (BUN) levels were measured by enzyme-linked immunosorbent assay. Pathology of the gastrocnemius muscle was estimated using hematoxylin and eosin staining. The expression of mitophagy-related markers was detected to assess the mitophagy level. Dexamethasone-induced L6 myotubes established myotube atrophy models. The levels of mitophagy-related markers, muscle RING-finger protein-1 (MuRF1), and atrophy gene 1 (Atrogin1) were detected by quantitative reverse transcription-polymerase chain reaction and western blotting. F. prausnitzii suppressed the SCR, UPR, and BUN expression in serum and gastrocnemius muscle atrophy, which were promoted by CRF with PEW. Dexamethasone-induced expression of MuRF1 and Atrogin1 in L6 myotubes was decreased by F. prausnitzii. Additionally, F. prausnitzii repressed mitophagy in the gastrocnemius muscle and L6 myotubes. In conclusion, F. prausnitzii suppressed renal failure progression and muscle atrophy by inhibiting mitophagy in CRF with PEW.

Mitochondrial ROS-associated integrated stress response is involved in arsenic-induced blood-testis barrier disruption and protective effect of melatonin

Arsenic (As) is an environmental metalloid. Previous studies have demonstrated that As exposure resulted in decline of sperm quality. This study aimed to investigate the impact of exposure to As on blood-testis barrier (BTB) in a mouse model. Four-week-old male mice were exposed to NaAsO2 (1 or 15 mg/L) for 6 weeks. Our results found that NaAsO2 exposure disrupted the BTB and reduced sperm counts in adult mice. NaAsO2 activated the integrated stress response (ISR) and downregulated barrier junction protein in mouse testes and Sertoli cells. Ribosome profiling sequencing (Ribo-seq) and Ribosome-nascent chain complex-bound mRNA qPCR (RNC-qPCR) showed that translational efficiency of N-cadherin and ZO-1, two key barrier junction proteins, was reduced in NaAsO2-treated Sertoli cells. Mechanistically, NaAsO2 exposure reduced SIRT3 protein via proteasomal degradation, thereby resulting in mitochondrial dysfunction and excess mitochondrial ROS (mtROS) generation in Sertoli cells. Melatonin alleviated NaAsO2-induced mitochondrial dysfunction and mtROS upregulation via reducing SOD2 acetylation in Sertoli cells. Moreover, melatonin antagonized NaAsO2-induced ISR, barrier junction proteins downregulation and barrier function impairment in Sertoli cells. Accordingly, melatonin attenuated NaAsO2-evoked BTB disruption and sperm count reduction in adult mice. These results suggest that mitochondrial dysfunction-associated translational inhibition of barrier junction proteins is involved in As-mediated BTB disruption and sperm quality decline.

Remote Ischemic Preconditioning Attenuates Mitochondrial Dysfunction and Ferroptosis of Tubular Epithelial Cells by Inhibiting NOX4-ROS Signaling in Acute Kidney Injury

Acute kidney injury (AKI) is a worldwide clinical burden associated with high morbidity and mortality. Remote ischemic preconditioning (rIPC), a brief nonlethal ischemia and reperfusion (IR) in remote tissues or limbs, has been used in an attempt to protect against AKI, but its underlying signaling pathways has not been elucidated. In the present study, rIPC protected kidney function and pathological injury and mitigated NADPH oxidase 4 (NOX4) upregulation in different AKI models (cisplatin, LPS and IRI). Furthermore, rIPC significantly attenuated mitochondrial dysfunction and ameliorated tubular epithelial ferroptosis during AKI. Mechanistically, in wild-type AKI mice and TCMK-1 cells, rIPC effectively decreased kidney ROS production, preserved mitochondrial dynamics and mitophagy, and ameliorated tubular epithelial ferroptosis. Notably, these protective effects of rIPC were further enhanced by NOX4 knockout or silencing and mitigated by NOX4 overexpression. Our study showed that rIPC may attenuate mitochondrial dysfunction and ferroptosis in tubular epithelial cells in AKI by inhibiting NOX4-ROS signaling. NOX4 might be used as a biomarker for monitoring the biological effects of rIPC to optimize the rIPC protocol and facilitate future translational studies.

Melatonin Exerts Positive Effects on Sepsis Through Various Beneficial Mechanisms

In recent years, our understanding of sepsis has greatly advanced. However, due to the complex pathological and physiological mechanisms of sepsis, the mechanisms of sepsis are currently not fully elucidated, and it is difficult to translate the research results into specific sepsis treatment methods. Melatonin possesses broad anti-inflammatory, antioxidant, and immune-regulatory properties, making it a promising therapeutic agent for sepsis. In recent years, further research has deepened our understanding of the potential mechanisms and application prospects of melatonin in sepsis. The mechanisms underlying the protective effects of melatonin in sepsis are multifaceted. In this review, based on a substantial body of clinical trials and animal research findings, we first highlighted the significance of melatonin as an important biomarker for disease progression and prognosis in sepsis. We also described the extensive regulatory mechanisms of melatonin in sepsis-induced organ damage. In addition to its broad anti-inflammatory, and anti-oxidant effects, melatonin exerts positive effects by regulating metabolic disorders, hemodynamics, cell autophagy, cellular ion channels, endothelial cell permeability, ferroptosis and other complex pathological mechanisms. Furthermore, as a safe exogenous supplement with low toxicity, melatonin demonstrates positive synergistic effects with other anti-sepsis agents. In the face of the urgent medical challenge of transforming the increasing knowledge of sepsis molecular mechanisms into therapeutic interventions to improve patient prognosis, melatonin seems to be a promising option.

Role of AIM2 and cGAS-STING signaling in high fat high carbohydrate diet-induced gut dysbiosis associated neurodegeneration

AIMS

Gut dysbiosis modulates CNS complications and cognitive decline through the gut-brain axis. The study aims to investigate the molecular mechanisms involved in gut dysbiosis-associated cognitive changes and the potential effects of probiotics in high fat-high carbohydrate diet-induced gut dysbiosis-associated neurodegeneration.

MATERIALS AND METHODS

We used high fat, high-carbohydrate diet (HFHCD) and high-fat diet (HFD) to induce gut dysbiosis-associated neurodegeneration in C57BL/6 mice. IVIS imaging system and biochemical changes using ELISA measured intestinal inflammation. We used fecal samples for qPCR profiling of intestinal bacteria, and serum was used for inflammatory marker analysis using ELISA. Behavioral studies measured cognitive changes, while histopathology, immunohistochemistry, and western blot analysis of hippocampal samples measured protein changes.

KEY FINDINGS

The behavioral studies showed a significant decrease in cognitive function associated with gut dysbiosis in HFHCD and HFD animals. Gut dysbiosis was associated with intestinal inflammation and increased intestinal permeability, followed by systemic and neuroinflammatory changes. Molecular signaling studies showed the involvement of AIM2 inflammasome and cGAS-STING signaling pathways in neurodegeneration for HFHCD animals. Administration of probiotics restored the above processes and prevented gut dysbiosis-associated memory decline in mice.

SIGNIFICANCE

The study shows that alteration in microbial composition due to prolonged HFHCD could contribute to intestinal inflammation and increased intestinal permeability, facilitating the translocation of microbial toxins like LPS, leading to systemic inflammation, which eventually leads to neuroinflammation and neurodegeneration.

A Mitochondrion-Targeting Piezoelectric Nanosystem for the Treatment of Erectile Dysfunction via Autophagy Regulation

Mitochondrial damage caused by external stimuli, such as high glucose levels and inflammation, results in excessive reactive oxygen species (ROS) production. Existing antioxidants can only scavenge ROS and cannot address the root cause of ROS production, namely, abnormal mitochondria. To overcome this limitation, the study develops a piezoelectric synergistic drug-loaded nanosystem (BaTCG nanosystem) that targets mitochondria. The BaTCG nanosystem is delivered to mitochondria via triphenylphosphine modification, and generates current under the stimulation of ultrasound, thereby promoting mitochondrial autophagy and restoring mitochondrial  homeostasis. In a model of diabetes-related erectile dysfunction (ED), the BaTCG nanosystem, through the current induced by the piezoelectric effect, not only promoted mitophagy, thereby reducing ROS production, but also released long-acting glucagon-like peptide-1 receptor agonists (GLP-1RAs) to effectively reduce blood glucose levels and mitochondrial damage. Each component of this nanosystem functions individually as well as synergistically, thus facilitating corpus cavernosum repair and restoring erectile function. In conclusion, the findings offer a novel therapeutic strategy for diabetes-related ED and a target for the treatment of diabetes-related conditions with functionalized nanoparticles to regulate mitophagy.

Roles of SIRT3 in cardiovascular and neurodegenerative diseases

Sirtuin-3 (SIRT3) in mitochondria has nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylase activity. As such, SIRT3 is crucial in cardiovascular and neurodegenerative diseases. Advanced proteomics and transcriptomics studies have revealed that SIRT3 expression becomes altered when the heart or brain is affected by external stimuli or disease, such as diabetic cardiomyopathy, atherosclerosis, myocardial infarction, Alzheimer's disease, Huntington's disease, and Parkinson's disease. More specifically, SIRT3 participates in the development of these disorders through its deacetylase activity and in combination with downstream signaling pathways. The paper reviews SIRT3's expression changes, roles, and mechanisms associated with the development of cardiovascular and neurodegenerative diseases. Additionally, strategies targeting SIRT3 to treat or regulate cardiovascular and neurodegenerative disease development are discussed.

INHIBITING SIRT2 ATTENUATES SEPSIS-INDUCED ACUTE KIDNEY INJURY VIA FOXO1 ACETYLATION-MEDIATED AUTOPHAGY ACTIVATION

ABSTRACT

Sepsis-associated acute kidney injury (SAKI), a common complication in intensive care units (ICUs), is linked to high morbidity and mortality. Sirtuin 2 (SIRT2), an NAD + -dependent deacetylase, has been shown to have distinct effects on autophagy regulation compared to other sirtuins, but its role in SAKI remains unclear. This study explored the potential of SIRT2 as a therapeutic target for SAKI. We found that inhibition of SIRT2 with the antagonist AGK2 improved the survival of septic mice. SIRT2 inhibition reduced kidney injury, as indicated by lower levels of KIM-1, NGAL, serum creatinine, blood urea nitrogen, and proinflammatory cytokines following cecal ligation and puncture. Pretreatment with AGK2 in septic mice increased autophagosome and autolysosome formation in renal tubular epithelial cells and upregulated LC3 II expression in the renal cortex. Consistent with in vivo findings, SIRT2 gene silencing promoted autophagy in LPS-treated HK-2 cells, whereas SIRT2 overexpression inhibited it. Mechanistically, SIRT2 inhibition increased FOXO1 acetylation, inducing its nuclear-to-cytoplasmic translocation, which promoted kidney autophagy and alleviated SAKI. Our study suggests SIRT2 as a potential target for SAKI therapy.

Isovitexin targets SIRT3 to prevent steroid-induced osteonecrosis of the femoral head by modulating mitophagy-mediated ferroptosis

The death of osteoblasts induced by glucocorticoid (GC)-mediated oxidative stress plays a crucial role in the development of steroid-induced osteonecrosis of the femoral head (SIONFH). Improving bone formation driven by osteoblasts has shown promising outcomes in the prognosis of SIONFH. Isovitexin has demonstrated antioxidant properties, but its therapeutic effects on GC-induced oxidative stress and SIONFH remain unexplored. In this study, we analyzed clinical samples obtained from SIONFH patients using proteomic and bioinformatic approaches. We found an imbalance in mitochondrial homeostasis and ferroptosis-induced impairment of osteogenic capacity in SIONFH. Subsequently, we investigated the cause-and-effect relationship between mitochondria and ferroptosis, as well as the regulatory role of mitophagy in maintaining mitochondrial homeostasis and controlling ferroptosis. We then identified the critical involvement of SIRT3 in modulating mitochondrial homeostasis and ferroptosis. Furthermore, molecular docking and co-immunoprecipitation confirmed the strong interaction between SIRT3 and BNIP3. Strikingly, restoring SIRT3 expression significantly inhibited pathological mitophagy mediated by the BNIP3/NIX pathway. Additionally, we discovered that Isovitexin, by promoting SIRT3 expression, effectively regulated mitophagy, preserved mitochondrial homeostasis in osteoblasts, suppressed ferroptosis, and restored osteogenic capacity, leading to remarkable improvements in SIONFH. These findings reveal the effects and molecular mechanisms of Isovitexin on SIONFH and highlight the potential of targeting SIRT3 as a promising strategy to suppress mitophagy-mediated ferroptosis in osteoblasts and against SIONFH.

The potential of melatonin in sepsis-associated acute kidney injury: Mitochondrial protection and cGAS-STING signaling pathway

Melatonin (Mel) is known for various biological function, such as antioxidant and anti-inflammatory capabilities, as well as its ability to modulate immune responses, which can protect mitochondria and improve the prognosis of sepsis-associated acute kidney injury (SA-AKI). However, there is a multitude of theories regarding how Mel exerts its immune-modulating functions, with no consensus reached as of yet. We propose the protective effects of Mel on mitochondria are closely related to the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway in the immune-inflammatory response. We intraperitoneally injected H151 and Mel into SA-AKI mouse models to interfere the cGAS-STING signaling pathway. By comparing behavioral, pathological, and molecular biology results, we discovered that Mel could reduce cGAS-STING signaling pathway while greatly relieving kidney damage and function. In addition, Mel-treated mice showed a significant increase in autophagosome formations, which might be linked to the cGAS-STING signaling pathway. Our findings suggest that Mel protection on kidney injury in SA-AKI mice is partially attributed to the inhibition of the cGAS-STING signaling pathway.

CIRCTMCO3 ALLEVIATES SEPSIS-INDUCED ACUTE KIDNEY INJURY VIA REGULATING MIR-218-5P/ZEB2 AXIS

ABSTRACT

Background: Growing evidence has found the critical role of circular RNAs (circRNAs) in sepsis-induced acute kidney injury (S-AKI). CircTMCO3 has been found to be involved in tumor microenvironment changes of ovarian cancer. This study aimed to explore whether circTMCO3 functions in S-AKI, and if so, to elucidate the molecular mechanism. Methods: CircTMCO3 expression was analyzed in lipopolysaccharide (LPS)-induced HK-2 cells and in the kidney tissues of mice treated with cecal ligation and puncture (CLP), respectively. Furthermore, the effects of circTMCO3 on S-AKI and the related mechanisms were evaluated in both models through gain- and/or loss-of-function strategies. Results: CircTMCO3 expression was suppressed in both S-AKI models. Upregulation of circTMCO3 mitigated LPS-induced apoptosis, oxidative stress, and inflammation in HK-2 cells. In contrast, circTMCO3 downregulation exacerbated LPS-induced injuries in HK-2 cells. Intravenous injection of circTMCO3 lentivirus to increase circTMCO3 expression improved renal function and attenuated kidney injury in S-AKI mice, as evidenced by the decrease in serum creatinine and blood urea nitrogen concentrations, amelioration of tubular pathological injury, reduction of renal cell apoptosis, and mitigation of oxidative stress and proinflammatory cytokines (TNF-α, IL-1β, and IL-6). Moreover, circTMCO3 directly targeted miR-218-5p, and the mimic of which abolished the protective effect of circTMCO3 in cell models. ZEB2 was identified to be a target of miR-218-5p; its downregulation not only reversed the impacts of miR-218-5p inhibitor on S-AKI, but also mitigated the effects mediated by circTMCO3 upregulation in vitro . Conclusions: CircTMCO3 protects against S-AKI by regulating miR-218-5p/ZEB2 axis, thereby mediating antiapoptotic, antioxidant, and anti-inflammatory activities. This indicates that increasing circTMCO3 expression might be a future therapeutic method for S-AKI.

Role of mitophagy in intervertebral disc degeneration: A narrative review

OBJECTIVE

The pivotal role of mitophagy in the initiation and progression of intervertebral disc (IVD) degeneration (IDD) has become increasingly apparent due to a growing body of research on its pathogenesis. This review summarizes the role of mitophagy in IDD and the therapeutic potential of targeting this process.

DESIGN

This narrative review is divided into three parts: the regulatory mechanisms of mitophagy, the role of mitophagy in IDD, and the applications and prospects of mitophagy for the treatment of IDD.

RESULTS

Mitophagy protects cells against harmful external stimuli and plays a crucial protective role by promoting extracellular matrix (ECM) production, inhibiting ECM degradation, and reducing apoptosis, senescence, and cartilage endplate calcification. However, excessive mitophagy is often detrimental to cells. Currently, the regulatory mechanisms governing appropriate and excessive mitophagy remain unclear.

CONCLUSIONS

Proper mitophagy effectively maintains IVD cell homeostasis and slows the progression of IDD. Conversely, excessive mitophagy may accelerate IDD development. Further research is needed to elucidate the regulatory mechanisms underlying appropriate and excessive mitophagy, which could provide new theoretical support for the application of mitophagy targeting to the treatment of IDD.

The connection between autophagy and ferroptosis in AKI: recent advances regarding selective autophagy

Acute kidney injury (AKI) is a significant issue in public health, displaying a high occurrence rate and mortality rate. Ferroptosis, a form of programmed cell death (PCD), is characterized by iron accumulation and intensified lipid peroxidation. Recent studies have demonstrated the pivotal significance of ferroptosis in AKI caused by diverse stimuli, including ischemia-reperfusion injury (IRI), sepsis and toxins. Autophagy, a multistep process that targets damaged organelles and macromolecules for degradation and recycling, also plays an essential role in AKI. Previous research has demonstrated that autophagy deletion in proximal tubules could aggravate tubular injury and renal function loss, indicating the protective function of autophagy in AKI. Consequently, finding ways to stimulate autophagy has become a crucial therapeutic strategy. The recent discovery of the role of selective autophagy in influencing ferroptosis has identified new therapeutic targets for AKI and has highlighted the importance of understanding the cross-talk between autophagy and ferroptosis. This study aims to provide an overview of the signaling pathways involved in ferroptosis and autophagy, focusing on the mechanisms and functions of selective autophagy and autophagy-dependent ferroptosis. We hope to establish a foundation for future investigations into the interaction between autophagy and ferroptosis in AKI as well as other diseases.

Dexmedetomidine inhibits ferroptosis and attenuates sepsis-induced acute kidney injury via activating the Nrf2/SLC7A11/FSP1/CoQ10 pathway

OBJECTIVES

The molecular mechanism underlying the protective effects of DEX against sepsis-induced acute kidney injury (SAKI) remains to be elucidated.

METHODS

We established S-AKI models in vivo via CLP and in vitro with LPS-induced HK-2 cells.

RESULTS

The Nrf2/SLC7A11/FSP1/CoQ10 pathway was inhibited in S-AKI both in vitro and in vivo. The overexpression of Nrf2 inhibited LPS-induced ferroptosis by activating the SLC7A11/FSP1/CoQ10 pathway. DEX ameliorated kidney tissue damage, as determined by a decrease in BUN, Cr, and inflammatory factor levels, along with renal tubule vacuolation and inflammatory cell infiltration in S-AKI mice. Additionally, DEX treatment significantly ameliorated ferroptosis in S-AKI in vitro and in vivo, as indicated by an improvement in mitochondrial shrinkage and disruption of cristae, a decrease in iron, ROS, MDA, and 4-HNE levels, and an increase in GSH and GPX4 levels. Mechanistically, DEX treatment restored the reduction of Nrf2 expression and nuclear translocation in S-AKI, as well as, the levels of downstream SLC7A11, FSP1, and CoQ10. Knocking down Nrf2 in vitro and administering brusatol in vivo eliminated the protective effect of DEX against S-AKI.

CONCLUSIONS

DEX mitigated ferroptosis and attenuated S-AKI by activating the Nrf2/SLC7A11/FSP1/CoQ10 pathway. Abbreviation: CLP: Cecal ligation puncture; LPS: Lipopolysaccharide; Nrf2: Nuclear factor-erythroid- 2-related factor 2; SLC7A11: Solute carrier family 7 member 11; FSP1: Ferroptosis suppressor protein 1; CoQ10: Coenzyme Q10; BUN: Blood urea nitrogen; Cr: Serum creatinine; ROS: Reactive oxygen species; MDA: Malondialdehyde; 4-HNE: 4-hydroxynonenal; GSH: Hlutathione; GPX4: Glutathione peroxidase 4.

Extracellular NCOA4 is a mediator of septic death by activating the AGER-NFKB pathway

Sepsis, a life-threatening condition resulting from a dysregulated response to pathogen infection, poses a significant challenge in clinical management. Here, we report a novel role for the autophagy receptor NCOA4 in the pathogenesis of sepsis. Activated macrophages and monocytes secrete NCOA4, which acts as a mediator of septic death in mice. Mechanistically, lipopolysaccharide, a major component of the outer membrane of Gram-negative bacteria, induces NCOA4 secretion through autophagy-dependent lysosomal exocytosis mediated by ATG5 and MCOLN1. Moreover, bacterial infection with E. coli or S. enterica leads to passive release of NCOA4 during GSDMD-mediated pyroptosis. Upon release, extracellular NCOA4 triggers the activation of the proinflammatory transcription factor NFKB/NF-κB by promoting the degradation of NFKBIA/IκB molecules. This process is dependent on the pattern recognition receptor AGER, rather than TLR4. In vivo studies employing endotoxemia and polymicrobial sepsis mouse models reveal that a monoclonal neutralizing antibody targeting NCOA4 or AGER delays animal death, protects against organ damage, and attenuates systemic inflammation. Furthermore, elevated plasma NCOA4 levels in septic patients, particularly in non-survivors, correlate positively with the sequential organ failure assessment score and concentrations of lactate and proinflammatory mediators, such as TNF, IL1B, IL6, and HMGB1. These findings demonstrate a previously unrecognized role of extracellular NCOA4 in inflammation, suggesting it as a potential therapeutic target for severe infectious diseases. Abbreviation: BMDMs: bone marrow-derived macrophages; BUN: blood urea nitrogen; CLP: cecal ligation and puncture; ELISA: enzyme-linked immunosorbent assay; LPS: lipopolysaccharide; NO: nitric oxide; SOFA: sequential organ failure assessment.

Integrin subunit beta 6 is a potential diagnostic marker for acute kidney injury in patients with diabetic kidney disease: a single cell sequencing data analysis

BACKGROUND

Diabetic kidney disease (DKD), a prevalent complication of diabetes mellitus, is often associated with acute kidney injury (AKI). Thus, the development of preventive and therapeutic strategies is crucial for delaying the progression of AKI and DKD.

METHODS

The GSE183276 dataset, comprising the data of 20 healthy controls and 12 patients with AKI, was downloaded from the Gene Expression Omnibus (GEO) database to analyze the AKI group. For analyzing the DKD group, the GSE131822 dataset, comprising the data of 3 healthy controls and 3 patients with DKD, was downloaded from the GEO database. The common differentially expressed genes (DEGs) in renal tubular epithelial cells (TECs) were subjected to enrichment analyses. Next, a protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes database to analyze gene-related regulatory networks. Finally, the AKI animal models and the DKD and AKI cell models were established, and the reliability of the identified genes was validated using quantitative real-time polymerase chain reaction analysis.

RESULTS

Functional analysis was performed with 40 common DEGs in TECs. Eight hub genes were identified using the PPI and gene-related networks. Finally, validation experiments with the in vivo animal model and the in vitro cellular model revealed the four common DEGs. Four DEGs that share molecular mechanisms in the pathogenesis of DKD and AKI were identified. In particular, the expression of Integrin Subunit Beta 6(ITGB6), a hub and commonly upregulated gene, was upregulated in the in vitro models.

CONCLUSION

ITGB6 may serve as a biomarker for early AKI diagnosis in patients with DKD and as a target for early intervention therapies.

Therapeutic effect of recombinant Echinococcus granulosus antigen B subunit 2 protein on sepsis in a mouse model

BACKGROUND

Sepsis is a potentially fatal systemic inflammatory response syndrome (SIRS) that threatens millions of lives worldwide. Echinococcus granulosus antigen B (EgAgB) is a protein released by the larvae of the tapeworm. This protein has been shown to play an important role in modulating host immune response. In this study we expressed EgAgB as soluble recombinant protein in E. coli (rEgAgB) and explored its protective effect on sepsis.

METHODS

The sepsis model was established by cecal ligation and puncture (CLP) procedure in BALB/c mice. The therapeutic effect of rEgAgB on sepsis was performed by interperitoneally injecting 5 µg rEgAgB in mice with CLP-induced sepsis and observing the 72 h survival rate after onset of sepsis. The proinflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-6] and regulatory cytokines [IL-10, transforming growth factor beta (TGF-β)] were measured in sera, and the histopathological change was observed in livers, kidneys, and lungs of septic mice treated with rEgAgB compared with untreated mice. The effect of rEgAgB on the macrophage polarization was performed in vitro by incubating rEgAgB with peritoneal macrophages. The levels of TLR2 and MyD88 were measured in these tissues to determine the involvement of TLR-2/MyD88 in the sepsis-induced inflammatory signaling pathway.

RESULTS

In vivo, we observed that treatment with rEgAgB significantly increased the survival rate of mice with CLP-induced sepsis up to 72 h while all mice without treatment died within the same period. The increased survival was associated with reduced pathological damage in key organs such as liver, lung, and kidneys. It was supported by the reduced proinflammatory cytokine levels and increased regulatory cytokine expression in peripheral blood and key organ tissues. Further study identified that treatment with rEgAgB promoted macrophage polarization from classically activated macrophage (M1) to regulatory M2-like macrophage via inhibiting TLR2/MyD88 signal pathway.

CONCLUSIONS

The therapeutic effects of rEgAgB on mice with sepsis was observed in a mice model that was associated with reduced inflammatory responses and increased regulatory responses, possibly through inducing polarization of macrophages from proinflammatory M1 to regulatory M2 phenotype through inhibiting TLR2/MyD88 inflammatory pathway.

Bacillus amyloliquefaciens SC06 alleviates LPS-induced intestinal damage by inhibiting endoplasmic reticulum stress and mitochondrial dysfunction in piglets

Endoplasmic reticulum stress (ERS) and mitochondrial dysfunction play an important role in the pathogenesis of intestinal diseases. Our studies investigated the effects of Bacillus amyloliquefaciens SC06 on jejunal mitochondria and ER in piglets under the LPS-induced intestinal injury model. Eighteen piglets (male, 21 days old) were randomly assigned to three treatments: CON (basal diet), LPS (basal diet +100 μg/kg LPS), and SC06 + LPS (basal diet +1 × 108 cfu/kg SC06 + 100 μg/kg LPS). Compared to the LPS group, administration of SC06 improved jejunal morphology and barrier function. In addition, SC06 reduced reactive oxygen species (ROS) and MDA generation in the jejunum by activating the Nrf2/keap1 pathway, which increased the activity of CAT, GSH and SOD in LPS-challenged pigs. In addition, SC06 reduced LPS-induced mitochondrial dysfunction and ERS as evidenced by a decrease in ROS, an improvement in mitochondrial membrane potential and an increase in adenosine triphosphate levels. The results of in vitro IPEC-J2 cell experiments also indicate that SC06 can reduce LPS-induced oxidative stress, mitochondrial dysfunction, ERS, and intestinal barrier function damage by activating the Nrf2/keap1 signaling pathway. Finally, treatment with the Nrf2-specific inhibitor ML-385 inhibited the upregulated effect of SC06 on antioxidant capacity and intestinal barrier function in IPEC-J2 cells. In conclusion, SC06 ameliorated intestinal damage and mitochondrial dysfunction and attenuated endoplasmic reticulum stress via activation of the Nrf2/keap1 signaling pathway in LPS-challenged piglets.

The role of inflammatory response and metabolic reprogramming in sepsis-associated acute kidney injury: mechanistic insights and therapeutic potential

Sepsis represents a severe condition characterized by organ dysfunction resulting from a dysregulated host response to infection. Among the organs affected, the kidneys are particularly vulnerable, with significant functional impairment that markedly elevates mortality rates. Previous researches have highlighted that both inflammatory response dysregulation and metabolic reprogramming are crucial in the onset and progression of sepsis associated acute kidney injury (SA-AKI), making these processes potential targets for innovative therapies. This study aims to elucidate the pathophysiological mechanisms of renal injury in sepsis by perspective of inflammatory response dysregulation, with particular emphasis on pyroptosis, necroptosis, autophagy, and ferroptosis. Furthermore, it will incorporate insights into metabolic reprogramming to provide a detailed analysis of the mechanisms driving SA-AKI and explore potential targeted therapeutic strategies, providing solid theoretical framework for the development of targeted therapies for SA-AKI.

Rab8a Is a Key Target That Melatonin Prevents Lipid Disorder from Atrazine

Atrazine (ATZ), a widely used herbicide, disrupts mitochondrial function and lipid metabolism in the liver. Melatonin (MLT), a naturally synthesized hormone, combats mitochondrial dysfunction and alleviates lipid toxicity. However, the mechanisms behind ATZ-induced lipid metabolism toxicity and the protective effects of MLT remain unexplored. Mice were randomly assigned to four groups: control (Con), 5 mg/kg MLT, 170 mg/kg ATZ, and a cotreatment group receiving 170 mg/kg ATZ with 5 mg/kg MLT (ATZ+MLT). Additionally, we analyzed the effects of MLT and Rab8a on mRNA and proteins related to mitochondrial function and lipid metabolism disrupted by ATZ in AML12 cells. In conclusion, ATZ induced mitochondrial stress and disrupted fatty acid metabolism in mouse hepatocytes and AML12 cells. Exogenous MLT restores Rab8a levels, regulating fatty acid utilization in mitochondria and mitochondrial function. Notably, targeting Rab8a does not significantly affect mitochondrial function but prevents ATZ-induced lipid metabolism disorders in hepatocytes.

Diagnostic value of the Sirtuins family in acute rejection of kidney transplantation assessed on the basis of transcriptomics and animal experiments

BACKGROUND

The Sirtuins (SIRT) family plays a key role in the diagnosis and treatment of many renal diseases, but no studies have been reported in acute rejection of kidney transplantation. The aim of this study was to explore the diagnostic value of SIRT family change characteristics in acute rejection of kidney transplantation.

METHODS

We first explored the SIRT family expression profile in renal tissues using the HPA database; subsequently, we explored the potential biological functions and mechanistic changes during acute rejection of kidney transplantation by GSEA enrichment analysis. The Cibersort algorithm specifies the level of immune cell infiltration and explores the correlation between the SIRT family and immune cells using correlation analysis; Next, we constructed a diagnostic model using "Logistic regression analysis" and "Nomogram model", and evaluated the diagnostic model using calibration curves and ROC curves, and the decision curve (DCA) was used to evaluate the clinical diagnostic value of SIRT family changes; Finally, we constructed a model of acute rejection of rat kidney transplantation, and assessed rat kidney function by detecting the levels of urea nitrogen and creatinine in serum. Meanwhile, the expression level of SIRT family in kidney tissues was initially verified by transcriptome sequencing and RT-PCR.

RESULTS

We found that all seven SIRT family members were located and expressed in renal tissues. The results of enrichment analysis revealed that a large number of immune-related biological functions and pathways are activated during acute rejection of kidney transplantation, the difference was statistically significant (p < 0.05). The Cibersort algorithm revealed significant changes in the level of infiltration of 10 immune cells (p < 0.05), while correlation analysis revealed a strong link between the SIRT family and immune cells (p < 0.05). We constructed a diagnostic model for acute rejection using seven SIRT families, and the ROC curves(AUC = 0.71)and calibration curves proved their good diagnostic value, and the DCA curves also proved the role of SIRT families in clinical decision-making. Next, we again demonstrated the good diagnostic performance of the SIRT family in ABMR and TCMR, respectively(ROC curves:AUC = 0.64，AUC = 0.81). Finally, in a rat model of acute rejection of kidney transplantation, we found that renal function (BUN and creatinine) was significantly impaired in rats in the Allo group compared to rats in the Syn group (P < 0.05). Meanwhile, by transcriptome analysis and RT-PCR assay, we found that, except for SIRT1, the remaining SIRT family members were significantly changed in kidney tissues (P < 0.05).

CONCLUSION

The SIRT family has significant changes during acute rejection in kidney transplantation, and the SIRT family may be able to serve as a potential therapeutic target for alleviating acute rejection in kidney transplantation.

Obtusifolin inhibits podocyte apoptosis by inactivating NF-κB signaling in acute kidney injury

Acute kidney injury (AKI) is a common clinical condition and is associated with unacceptable morbidity and mortality. Obtusifolin is an anthraquinone extracted from the seeds of Cassia obtusifolia with anti-inflammatory properties. This study focused on the role and mechanism of obtusifolin in AKI. The mouse podocyte cell line MPC5 was exposed to lipopolysaccharide (LPS) to establish a cell model of AKI. The viability of MPC5 cells treated with obtusifolin and/or LPS was detected by 3-(4, 5-Dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay. Cell apoptosis was analyzed by flow cytometry. The levels of podocyte injury- and apoptosis-related proteins as well as the nuclear factor-kappaB (NF-κB) signaling pathway was examined using western blotting analysis. The renal protective effects of obtusifolin were determined using an LPS-induced mouse model of AKI. Serum creatinine and blood urea nitrogen levels were measured. Hematoxylin-eosin staining of kidney sections was performed to evaluate renal histology. We found that MPC5 cells treated with LPS showed suppressed cell viability (p < 0.01) and increased cell apoptosis (p < 0.001). LPS reduced the protein expression of Bcl-2, nephrin, and synaptopodin as well as increased the protein levels of Bax and Cleaved Caspase-3 in podocytes in a concentration-dependent manner (p < 0.01). In addition, 10 μg/ml LPS-repressed cell viability was rescued by obtusifolin in a concentration-dependent manner (p < 0.01). Moreover, LPS-induced increase in MPC5 cell apoptosis was reversed by obtusifolin treatment (p < 0.01). Obtusifolin administration ameliorated LPS-induced kidney injury and reduced blood urea nitrogen and serum creatinine levels in mice (p < 0.001). Additionally, obtusifolin inhibited LPS-induced activation of NF-κB signaling in vitro and in vivo (p < 0.01). Overall, obtusifolin was effective in protecting renal function against LPS-induced AKI via inactivation of NF-κB signaling, which suggested that obtusifolin may act as a valuable agent for AKI therapy.

Effect of alternating nicotinamide phosphoribosyltransferase expression levels on mitophagy in Alzheimer's disease mouse models

AD is the abbreviation for Alzheimer's Disease, which is a neurodegenerative disorder that features progressive dysfunction in cognition. Previous research has reported that mitophagy impairment and mitochondrial dysfunction have been crucial factors in the AD's pathogenesis. More recently, literature has emerged which offers findings suggesting that the nicotinamide adenine dinucleotide (short for NAD+) augmentation eliminates the defective mitochondria and restores mitophagy. Meanwhile, as an enzyme which is rate-limiting, the Nicotinamide phosphoribosyltransferase, or NAMPT, is part of the salvage pathway of NAD+ synthesis. Therefore, the aim of the research project has been to produce proof for how the NAMPT-NAD +-silent information-regulated transcription factors1/3 (short for SIRT1/3) axis function in mediating mitophagy in APP/PS1 mice aged six months. The results revealed that the NAMPT-NAD+-SIRT1/3 axis in the APP/PS1 mice's hippocampus was considerably declined. Surprisingly, P7C3 (an NAMPT activator) noticeably promoted the NAD+-SIRT1/3 axis, improved mitochondrial structure and function, enhanced mitophagy activity along with the ability of learning and memory. While FK866 (an NAMPT inhibitor) reversed the decreased NAD+-SIRT1/3 axis, and even exacerbated Aβ plaque deposition level in the APP/PS1 mice's hippocampus. The findings observed in this study indicate two main points: avoiding downregulation of the NAMPT activity can prevent AD-related mitophagy impairment; on the other hand, NAMPT characterizes a potential therapeutic intervention regarding AD pathogenesis.

Role of sirtuins in sepsis and sepsis-induced organ dysfunction: A review

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis causes a high mortality rate and current treatment focuses on supportive therapies but lacks specific therapeutic targets. Notably, sirtuins (SIRTs) shows potential clinical application in the treatment of sepsis. It has been demonstrated that SIRTs, the nicotinamide adenine dinucleotide+(NAD+)-dependent deacetylases that regulate key signaling pathways in eukaryotes and prokaryotes, are involved in a variety of biological processes. To date, seven mammalian yeast Sir2 homologs have been identified. SIRTs can regulate inflammation, oxidative stress, apoptosis, autophagy, and other pathways that play important roles in sepsis-induced organ dysfunction. However, the existing studies on SIRTs in sepsis are too scattered, and there is no relevant literature to integrate them. This review innovatively summarizes the different mechanisms of SIRTs in sepsis organ dysfunction according to the different systems, and focuses on SIRT agonists, inhibitors, and targeted drugs that have been proved to be effective in the treatment of sepsis, so as to integrate the clinical research and basic research closely. We searched PubMed for all literature related to SIRTs and sepsis since its inception using the following medical subject headings: sirtuins, SIRTs, and sepsis. Data on the mechanisms of SIRTs in sepsis-induced organ damage and their potential as targets for disease treatment were extracted.

Elucidating the Role of Sirtuin 3 in Mammalian Oocyte Aging

The field of reproductive biology has made significant progress in recent years, identifying specific molecular players that influence oocyte development and function. Among them, sirtuin 3 (SIRT3) has attracted particular attention for its central role in mediating mitochondrial function and cellular stress responses in oocytes. So far, studies have demonstrated that the knockdown of SIRT3 leads to a decrease in blastocyst formation and an increase in oxidative stress within an embryo, underscoring the importance of SIRT3 in maintaining the cellular redox balance critical for embryonic survival and growth. Furthermore, the literature reveals specific signaling pathways, such as the SIRT3- Glycogen synthase kinase-3 beta (GSK3β) deacetylation pathway, crucial for mitigating oxidative stress-related anomalies in oocyte meiosis, particularly under conditions like maternal diabetes. Overall, the emerging role of SIRT3 in regulating oocyte mitochondrial function and development highlights the critical importance of understanding the intricate connections between cellular metabolism, stress response pathways, and overall reproductive health and function. This knowledge could lead to the development of novel strategies to support oocyte quality and fertility, with far-reaching implications for assisted reproductive technologies and women's healthcare. This commentary aims to provide an overview of the importance of SIRT3 in oocytes by synthesizing results from a multitude of studies. The aim is to elucidate the role of SIRT3 in oocyte development, maturation, and aging and to identify areas where further research is needed.

Dihydromyricetin ameliorates diabetic renal fibrosis via regulating SphK1 to suppress the activation of NF-κB pathway

Dihydromyricetin (DHM) is a flavonoid from vine tea with broad pharmacological benefits, which improve inflammation by blocking the NF-κB pathway. A growing body of research indicates that chronic kidney inflammation is vital to the pathogenesis of diabetic renal fibrosis. Sphingosine kinase-1 (SphK1) is a key regulator of diabetic renal inflammation, which triggers the NF-κB pathway. Hence, we evaluated whether DHM regulates diabetic renal inflammatory fibrosis by acting on SphK1. Here, we demonstrated that DHM effectively suppressed the synthesis of fibrotic and inflammatory adhesion factors like ICAM-1, and VCAM-1 in streptozotocin-treated high-fat diet-induced diabetic mice and HG-induced glomerular mesangial cells (GMCs). Moreover, DHM significantly suppressed NF-κB pathway activation and reduced SphK1 activity and protein expression under diabetic conditions. Mechanistically, the results of molecular docking, molecular dynamics simulation, and cellular thermal shift assay revealed that DHM stably bound to the binding pocket of SphK1, thereby reducing sphingosine-1-phosphate content and SphK1 enzymatic activity, which ultimately inhibited NF-κB DNA binding, transcriptional activity, and nuclear translocation. In conclusion, our data suggested that DHM inhibited SphK1 phosphorylation to prevent NF-κB activation thus ameliorating diabetic renal fibrosis. This supported the clinical use and further drug development of DHM as a potential candidate for treating diabetic renal fibrosis.

Melatonin in animal husbandry: functions and applications

Melatonin (N-acetyl-5-methoxytryptamine) is an essential small molecule with diverse biological functions. It plays several key roles, including regulating the secretion of reproductive hormones and the reproductive cycle, enhancing the functionality of reproductive organs, improving the quality of sperm and eggs, and mitigating oxidative stress in the reproductive system. Melatonin effectively inhibits and scavenges excess free radicals while activating the antioxidant enzyme system and reduces the production of inflammatory factors and alleviates tissue damage caused by inflammation by regulating inflammatory pathways. Additionally, melatonin contributes to repairing the intestinal barrier and regulating the gut microbiota, thereby reducing bacterial and toxin permeation. The use of melatonin as an endogenous hormone in animal husbandry has garnered considerable attention because of its positive effects on animal production performance, reproductive outcomes, stress adaptation, disease treatment, and environmental sustainability. This review explores the characteristics and biological functions of melatonin, along with its current applications in animal production. Our findings may serve as a reference for the use of melatonin in animal farming and future developmental directions.

Mesoporous zinc-polyphenol nanozyme for attenuating renal ischemia-reperfusion injury

Aim: To target the reactive oxygen species (ROS) accumulation and renal tubular epithelial cell (rTEC) death in renal ischemia-reperfusion injury (IRI), we constructed a nanoparticle that offers ROS scavenging and rTEC-death inhibition: mesoporous zinc-tannic acid nanozyme (ZnTA).Materials & methods: After successfully constructing ZnTA, we proceeded to examine its effect on ROS accumulation, cellular ferroptosis and apoptosis, as well as injury severity.Results: Malondialdehyde, Fe2+ amounts and 4-HNE staining demonstrated that ZnTA effectively attenuated rTEC ferroptosis. TUNEL staining confirmed that Zn2+ carried by ZnTA could effectively inhibit caspase 3 and caspase 9, mitigating apoptosis. Finally, it reduced renal IRI through the synergistic effect of ROS scavenging and cell-death inhibition.Conclusion: This study is expected to provide a paradigm for a combined therapeutic strategy for renal IRI.

Mitochondrial regulation in stem cells

Stem cells persist throughout the lifespan to repair and regenerate tissues due to their unique ability to self-renew and differentiate. Here we reflect on the recent discoveries in stem cells that highlight a mitochondrial metabolic checkpoint at the restriction point of the stem cell cycle. Mitochondrial activation supports stem cell proliferation and differentiation by providing energy supply and metabolites as signaling molecules. Concomitant mitochondrial stress can lead to loss of stem cell self-renewal and requires the surveillance of various mitochondrial quality control mechanisms. During aging, a mitochondrial protective program mediated by several sirtuins becomes dysregulated and can be targeted to reverse stem cell aging and tissue degeneration, giving hope for targeting the mitochondrial metabolic checkpoint for treating tissue degenerative diseases.

Sirtuin 3 in renal diseases and aging: From mechanisms to potential therapies

The longevity protein sirtuins (SIRTs) belong to a family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases. In mammals, SIRTs comprise seven members (SIRT1-7) which are localized to different subcellular compartments. As the most prominent mitochondrial deacetylases, SIRT3 is known to be regulated by various mechanisms and participate in virtually all aspects of mitochondrial homeostasis and metabolism, exerting significant impact on multiple organs. Notably, the kidneys possess an abundance of mitochondria that provide substantial energy for filtration and reabsorption. A growing body of evidence now supports the involvement of SIRT3 in several renal diseases, including acute kidney injury, chronic kidney disease, and diabetic nephropathy; notably, these diseases are all associated with aging. In this review, we summarize the emerging role of SIRT3 in renal diseases and aging, and highlights the intricate mechanisms by which SIRT3 exerts its effects. In addition, we highlight the potential therapeutic significance of modulating SIRT3 and provide valuable insights into the therapeutic role of SIRT3 in renal diseases to facilitate clinical application.

Melatonin attenuates scopolamine-induced cognitive dysfunction through SIRT1/IRE1α/XBP1 pathway

BACKGROUND

The prevalence of dementia around the world is increasing, and these patients are more likely to have cognitive impairments, mood and anxiety disorders (depression, anxiety, and panic disorder), and attention deficit disorders over their lifetime. Previous studies have proven that melatonin could improve memory loss, but its specific mechanism is still confused.

METHODS

In this study, we used in vivo and in vitro models to examine the neuroprotective effect of melatonin on scopolamine (SCOP)-induced cognitive dysfunction. The behavioral tests were performed. 18F-FDG PET imaging was used to assess the metabolism of the brain. Protein expressions were determined through kit detection, Western blot, and immunofluorescence. Nissl staining was conducted to reflect neurodegeneration. MTT assay and RNAi transfection were applied to perform the in vitro experiments.

RESULTS

We found that melatonin could ameliorate SCOP-induced cognitive dysfunction and relieve anxious-like behaviors or HT22 cell damage. 18F-FDG PET-CT results showed that melatonin could improve cerebral glucose uptake in SCOP-treated mice. Melatonin restored the cholinergic function, increased the expressions of neurotrophic factors, and ameliorated oxidative stress in the brain of SCOP-treated mice. In addition, melatonin upregulated the expression of silent information regulator 1 (SIRT1), which further relieved endoplasmic reticulum (ER) stress by decreasing the expression of phosphorylate inositol-requiring enzyme (p-IRE1α) and its downstream, X-box binding protein 1 (XBP1).

CONCLUSIONS

These results indicated that melatonin could ameliorate SCOP-induced cognitive dysfunction through the SIRT1/IRE1α/XBP1 pathway. SIRT1 might be the critical target of melatonin in the treatment of dementia.