Role of AMPK/SIRT1-SIRT3 signaling pathway in affective disorders in unpredictable chronic mild stress mice

Role of sirtuin 1 in depression‑induced coronary heart disease: Molecular pathways and therapeutic potential (Review)

Depression and coronary heart disease (CHD) are two interconnected diseases that profoundly impact global health. Depression is both a complex psychiatric disorder and an established risk factor for CHD. Sirtuin 1 (SIRT1) is an enzyme that requires the cofactor nicotinamide adenine dinucleotide (NAD+) to perform its deacetylation function, and its involvement is crucial in reducing cardiovascular risks that are associated with depression. SIRT1 exerts its cardioprotective effects via modulating oxidative stress, inflammation and metabolic processes, all of which are central to the pathogenesis of CHD in individuals with depression. Through influencing these pathways, SIRT1 helps to reduce endothelial dysfunction, prevent the formation of atherosclerotic plaques and stabilize existing plaques, thereby decreasing the overall risk of CHD. The present review underscores the important role of SIRT1 in serving as a therapeutic intervention molecule for tackling cardiovascular complications stemming from depression. Furthermore, it highlights the need for further studies to clarify how SIRT1 influences both depression and CHD at the molecular level. The ultimate goal of this research will be to translate these findings into practical clinical intervention strategies.

Pharmacological Mechanism and Drug Research Prospects of Ginsenoside Rb1 as an Antidepressant

This review explores the antidepressant effects of ginsenoside Rb1, a natural compound in traditional Chinese medicine, and its potential for treating major depressive disorder (MDD). The aetiology of depression was reviewed up to 2024, focusing on the pathways and mechanisms through which ginsenoside Rb1 may exert its effects. Notably, ginsenoside Rb1 regulates oxidative stress and inflammatory processes while enhancing neural plasticity by downregulating miR-134 expression and alleviating depressive symptoms. Unlike traditional antidepressants that act on a single target, ginsenoside Rb1 interacts with multiple pathways, reflecting its potential for broader therapeutic application. To compensate for the current deficiency in animal experiments, clinical data, and research on the side effects of ginsenoside Rb1 in the treatment of depression, we reviewed some clinical data on the use of this component in the treatment of other diseases to explore its relevance to depression. Ginsenoside Rb1 is expected to serve as a novel antidepressant or as a complementary component in combination with other antidepressant compounds. However, further clinical trials and molecular studies are necessary to confirm its efficacy and potential side effects.

The Structures, Functions, and Roles of Class III HDACs (Sirtuins) in Neuropsychiatric Diseases

Over the past two decades, epigenetic regulation has become a rapidly growing and influential field in biology and medicine. One key mechanism involves the acetylation and deacetylation of lysine residues on histone core proteins and other critical proteins that regulate gene expression and cellular signaling. Although histone deacetylases (HDACs) have received significant attention, the roles of individual HDAC isoforms in the pathogenesis of psychiatric diseases still require further research. This is particularly true with regard to the sirtuins, class III HDACs. Sirtuins have unique functional activity and significant roles in normal neurophysiology, as well as in the mechanisms of addiction, mood disorders, and other neuropsychiatric abnormalities. This review aims to elucidate the differences in catalytic structure and function of the seven sirtuins as they relate to psychiatry.

cAMP-PKA signaling pathway and anxiety: Where do we go next?

Cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is derived from the conversion of adenosine triphosphate catalysed by adenylyl cyclase (AC). Protein kinase A (PKA), the main effector of cAMP, is a dimeric protein kinase consisting of two catalytic subunits and two regulatory subunits. When cAMP binds to the regulatory subunits of PKA, it leads to the dissociation and activation of PKA, which allows the catalytic subunit of PKA to phosphorylate target proteins, thereby regulating various physiological functions and metabolic processes in cellular function. Recent researches also implicate the involvement of cAMP-PKA signaling in the pathologenesis of anxiety disorder. However, there are still debates on the prevention and treatment of anxiety disorders from this signaling pathway. To review the function of cAMP-PKA signaling in anxiety disorder, we searched the publications with the keywords including "cAMP", "PKA" and "Anxiety" from Pubmed, Embase, Web of Science and CNKI databases. The results showed that the number of publications on cAMP-PKA pathway in anxiety disorder tended to increase. Bioinformatics results displayed a close association between the cAMP-PKA pathway and the occurrence of anxiety. Mechanistically, cAMP-PKA signaling could influence brain-derived neurotrophic factor and neuropeptide Y and participate in the regulation of anxiety. cAMP-PKA signaling could also oppose the dysfunctions of gamma-aminobutyric acid (GABA), intestinal flora, hypothalamic-pituitary-adrenal axis, neuroinflammation, and signaling proteins (MAPK and AMPK) in anxiety. In addition, chemical agents with the ability to activate cAMP-PKA signaling demonstrated therapy potential against anxiety disorders. This review emphasizes the central roles of cAMP-PKA signaling in anxiety and the targets of the cAMP-PKA pathway would be potential candidates for treatment of anxiety. Nevertheless, more laboratory investigations to improve the therapeutic effect and reduce the adverse effect, and continuous clinical research will warrant the drug development.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

Ginsenoside Rg1 Attenuates Chronic Sleep Deprivation-Induced Hippocampal Mitochondrial Dysfunction and Improves Memory by the AMPK-SIRT3 Pathway

Ginsenoside Rg1 (Rg1) is the main bioactive ginseng component. This study investigates the effects of Rg1 on cognitive deficits triggered by chronic sleep deprivation stress (CSDS) and explores its underlying mechanisms. Rg1 effectively improved spatial working and recognition memory, as evidenced by various behavioral tests. RNA-sequence analysis revealed differential gene expression in the metabolic pathway. Treatment with Rg1 abrogated reductions in SOD and CAT activity, lowered MDA content, and increased Nrf2 and HO-1 protein levels. Rg1 administration alleviated hippocampal mitochondrial dysfunction by restoring normal ultrastructure and enhancing ATP activities and Mfn2 expression while regulating Drp-1 expression. Rg1 mitigated neuronal apoptosis by reducing the Bax/Bcl-2 ratio and the levels of cleaved caspase-3. Additionally, Rg1 upregulated AMPK and SIRT3 protein expressions. These findings suggest that Rg1 has potential as a robust intervention for cognitive dysfunction associated with sleep deprivation, acting through the modulation of mitochondrial function, oxidative stress, apoptosis, and the AMPK-SIRT3 axis.

Taste receptor type 1 member 3 mediates diet-induced cognitive impairment in mice

AIMS

Long-term consumption of a western diet (WD), which is characterized by high intake of saturated fats and sugary drinks, causes cognitive impairment. However, the molecular mechanism by which WD induces cognitive impairment remains unclear. Taste receptor type 1 member 3 (TAS1R3), activated by ligands of WD, is expressed in extra-oral tissues, including the brain, and particularly in the hippocampus. This study investigated whether TAS1R3 regulates WD-induced cognitive impairment in mice.

MAIN METHODS

Male C57BL/6J wild-type (WT) and Tas1r3 knock-out (KO) mice were fed either a normal diet (ND) or WD for 18 weeks. Cognitive functions were assessed using novel object recognition and Barnes maze tests. The mechanisms underlying WD-induced cognitive impairment were assessed using RNA-sequencing and bioinformatics analysis.

KEY FINDINGS

Cognitive impairment was observed in WT mice fed WD (WT-WD) compared with WT-ND mice. Conversely, mice lacking TAS1R3 were not cognitively impaired even under long-term WD feeding. Hippocampal transcriptome analysis revealed upregulated AMP-activated protein kinase (AMPK) signaling and increased AMPK-targeted sirtuin 3 expression in KO-WD mice. Pathway enrichment analysis showed that response to oxidative stress was downregulated, whereas neurogenesis was upregulated in dentate gyrus of KO-WD mice. In vitro studies validated the findings, indicating that Tas1r3 knockdown directly upregulated decreased sirtuin 3 expression, its downstream genes-related to oxidative stress, and apoptosis induced by WD condition in hippocampal neuron cells.

SIGNIFICANCE

TAS1R3 acts as a critical mediator of WD-induced cognitive impairment in mice, thereby offering potential as a novel therapeutic target to prevent WD-induced cognitive impairment.

Targeting Mitochondrial Sirtuins in Age-Related Neurodegenerative Diseases and Fibrosis

Aging is a natural and complex biological process that is associated with widespread functional declines in numerous physiological processes, terminally affecting multiple organs and tissues. Fibrosis and neurodegenerative diseases (NDs) often occur with aging, imposing large burdens on public health worldwide, and there are currently no effective treatment strategies for these diseases. Mitochondrial sirtuins (SIRT3-5), which are members of the sirtuin family of NAD+-dependent deacylases and ADP-ribosyltransferases, are capable of regulating mitochondrial function by modifying mitochondrial proteins that participate in the regulation of cell survival under various physiological and pathological conditions. A growing body of evidence has revealed that SIRT3-5 exert protective effects against fibrosis in multiple organs and tissues, including the heart, liver, and kidney. SIRT3-5 are also involved in multiple age-related NDs, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. Furthermore, SIRT3-5 have been noted as promising targets for antifibrotic therapies and the treatment of NDs. This review systematically highlights recent advances in knowledge regarding the role of SIRT3-5 in fibrosis and NDs and discusses SIRT3-5 as therapeutic targets for NDs and fibrosis.

Resveratrol Attenuates Chronic Unpredictable Mild Stress-Induced Alterations in the SIRT1/PGC1α/SIRT3 Pathway and Associated Mitochondrial Dysfunction in Mice

Environmental challenges, specifically chronic stress, have long been associated with neuropsychiatric disorders, including anxiety and depression. Sirtuin-1 (SIRT1) is a NAD+-dependent deacetylase that is widely distributed in the cortex and is involved in stress responses and neuropsychiatric disorders. Nevertheless, how chronic stress modulates the SIRT1 pathway and associated signaling remains unclear. In this study, we first explored the impact of chronic unpredictable mild stress (CUMS) on the SIRT1/PGC1α/SIRT3 pathway, on GABAergic mechanisms, and on mitophagy, autophagy and apoptosis in mice. We also asked whether activation of SIRT1 by resveratrol (RSV) can attenuate CUMS-induced molecular and behavioral alterations. Two-month-old C57/BL6J mice were subjected to three weeks of CUMS and one week of RSV treatment (30 mg/kg; i.p.) during the third week of CUMS. CUMS caused downregulation of the SIRT1/PGC1α/SIRT3 pathway leading to impaired mitochondrial morphology and function. CUMS also resulted in a reduction in numbers of parvalbumin-positive interneurons and increased oxidative stress leading to reduced expression of autophagy- and mitophagy-related proteins. Strikingly, activation of SIRT1 by RSV ameliorated expression of SIRT1/PGC1α/SIRT3, and also improved mitochondrial function, GABAergic mechanisms, mitophagy, autophagy and apoptosis. RSV also rescued CUMS-induced anxiety-like and depressive-like behavior in mice. Our results raise the compelling possibility that RSV treatment might be a viable therapeutic method of blocking stress-induced behavioral alterations.

Polydatin Alleviates Chronic Stress-Induced Depressive and Anxiety-like Behaviors in a Mouse Model

We aimed to investigate whether polydatin could suppress stress-induced depression- and anxiety-like behaviors in a mouse model. Mice were divided into the control group, chronic unpredictable mild stress (CUMS) exposure group, and CUMS mice treated with polydatin group. Following CUMS exposure and polydatin treatment, mice were subjected to behavioral assays to assess depressive-like and anxiety-like behaviors. Synaptic function was determined by the levels of brain-derived neurotrophic factor (BDNF), postsynaptic density protein 95 (PSD95), and synaptophysin (SYN) in the hippocampus and cultured hippocampal neurons. The number and length of dendrites were assessed in cultured hippocampal neurons. Finally, we investigated the effect of polydatin on CUMS-induced inflammation and oxidative stress in the hippocampus by measuring inflammatory cytokine levels, oxidative stress markers such as reactive oxygen species, glutathione peroxidase, catalase, and superoxide dismutase, as well as components of the Nrf2 signaling pathway. Polydatin alleviated CUMS-induced depressive-like behaviors in forced swimming, tail suspension and sucrose preference tests, and anxiety-like behaviors in marble-burying and elevated plus maze tests. Polydatin increased the number and length of dendrites of cultured hippocampal neurons from mice exposed to CUMS and alleviated CUMS-induced synaptic deficits by restoring BDNF, PSD95, and SYN levels in vivo and in vitro. Importantly, polydatin inhibited CUMS-induced hippocampal inflammation and oxidative stress and suppressed the activation of NFκB and Nrf2 pathways. Our study suggests that polydatin may be an effective drug for the treatment of affective disorders through inhibiting neuroinflammation and oxidative stress. Our current findings warrant further study to investigate the potential clinical application of polydatin.

The sex-dependent response to psychosocial stress and ischaemic heart disease

Stress is an important risk factor for modern chronic diseases, with distinct influences in males and females. The sex specificity of the mammalian stress response contributes to the sex-dependent development and impacts of coronary artery disease (CAD). Compared to men, women appear to have greater susceptibility to chronic forms of psychosocial stress, extending beyond an increased incidence of mood disorders to include a 2- to 4-fold higher risk of stress-dependent myocardial infarction in women, and up to 10-fold higher risk of Takotsubo syndrome-a stress-dependent coronary-myocardial disorder most prevalent in post-menopausal women. Sex differences arise at all levels of the stress response: from initial perception of stress to behavioural, cognitive, and affective responses and longer-term disease outcomes. These fundamental differences involve interactions between chromosomal and gonadal determinants, (mal)adaptive epigenetic modulation across the lifespan (particularly in early life), and the extrinsic influences of socio-cultural, economic, and environmental factors. Pre-clinical investigations of biological mechanisms support distinct early life programming and a heightened corticolimbic-noradrenaline-neuroinflammatory reactivity in females vs. males, among implicated determinants of the chronic stress response. Unravelling the intrinsic molecular, cellular and systems biological basis of these differences, and their interactions with external lifestyle/socio-cultural determinants, can guide preventative and therapeutic strategies to better target coronary heart disease in a tailored sex-specific manner.

Dietary Hesperidin Suppresses Lipopolysaccharide-Induced Inflammation in Male Mice

Depressive disorders are partially attributed to chronic inflammation associated with the tryptophan (Trp)-kynurenine (Kyn) pathway. Recent evidence suggests that anti-inflammatory agents may reduce the risk of depression. The present study aimed to elucidate the potential of the citrus flavonoid hesperidin, which exhibits anti-inflammatory activity, in suppressing the Trp-Kyn pathway in the brain, using a lipopolysaccharide (LPS)-induced inflammation mouse model. Dietary hesperidin was found to suppress activation of the Trp-Kyn pathway in the prefrontal cortex. In addition, it reduced systemic LPS-induced signs of illness, such as low skin temperature and enhanced leukocyte count in the blood. However, dietary supplementation with hesperidin did not improve body weight loss, food intake, water intake, or splenic increases in leukocyte numbers in the LPS model. Collectively, the results suggest that dietary hesperidin can partially regulate central and peripheral events linked to inflammation in LPS mouse models.

Polydatin Prevents Neuroinflammation and Relieves Depression via Regulating Sirt1/HMGB1/NF-κB Signaling in Mice

Depression is a prevalent psychiatric disorder with a significant health impact and economic burden worldwide. Unfortunately, the exact pathogenesis of depression is not well understood. Neuroinflammation and microglial activation play an essential role in the pathogenesis of depression. Previous studies have shown that polydatin has anti-inflammatory and antioxidant properties. However, the link between polydatin and depression remains unclear. Therefore, the objective of this study was to investigate the antidepressant effect of polydatin in lipopolysaccharide (LPS)-induced depression in mice and its possible mechanism. Adult male C57BL/6 J mice were used in this study. The polydatin and LPS were injected intraperitoneally daily for 5 days. In addition, the EX527, an inhibitor of Sirt1, was injected intraperitoneally daily and 1 h before the polydatin injection. The behavior tests were performed to elucidate the depression-like behaviors. The Sirt1/HMGB1/NF-κB pathway expression was detected by western blot, ELISA, and immunofluorescence staining. Polydatin can significantly improve LPS-induced depression-like behavior in mice. Treatment with polydatin increased the expression of the Sirt1 but decreased the expression of the HMGB1, p-NF-κB, IL-1b, and TNF-α in the LPS-induced depression mice. In addition, the EX527 abolished the anti-depressive effects of the polydatin and the levels of Sirt1 protein. These findings suggested that the polydatin reversed the depressive effects through the Sirt1/HMGB1/NF-κB signaling in the LPS-induced depression mice. Therefore, polydatin can be used in the treatment of depression.

Aspirin blocks AMPK/SIRT3-mediated glycolysis to inhibit NSCLC cell proliferation

Non-small cell lung cancer (NSCLC) has the highest incidence and mortality in the world. Aspirin has been reported to promote apoptosis, inhibit proliferation, stemness, angiogenesis, cancer-associated inflammation and migration in NSCLC. But the effect of aspirin on aerobic glycolysis in NSCLC is less reported. In the present study, we investigated whether aspirin blocked aerobic glycolysis of NSCLC cells to inhibit proliferation. Our results showed that aspirin inhibited viability, PCNA expression, ability of colony formation, dimished extracellular acidification rate (ECAR), oxygen consumption rate (OCR) and production of pyruvic acid and lactic acid, accompanied with reduced mitochondrial membrane potential (MMP), PGC-1α expression and ROS production, indicating mitochondrial dysfunction in NSCLC cells. AMPK and mitochondrial-localized deacetylase sirtuin 3 (SIRT3) were identified as the relevant molecular targets in glycolysis, but mechanism and relationship between AMPK and SIRT3 for aspirin induced glycolysis inhibition remain unknown in cancer cells. The investigation of underlying mechanism indicated that aspirin activated AMPK pathway to inhibit aerobic glycolysis and proliferation by upregulating SIRT3 after application of compound C (CC), an inhibitor of AMPK activity or SIRT3 siRNA. Upon activation of SIRT3, aspirin promoted the release of hexokinase-II (HK-II) from mitochondrial outer membrane to cytosol by deacetylating cyclophilin D (CypD). Consistently, aspirin significantly inhibited the growth of NSCLC xenografts and exhibited antitumor activity probably through AMPK/SIRT3/HK-II pathway in vivo. Collectively, AMPK/SIRT3/HK-II pathway plays a critical role in anticancer effects of aspirin, and our findings might serve as potential target for clinical practice and chemoprevention of aspirin in NSCLC.

Beyond the behavioural phenotype: Uncovering mechanistic foundations in aquatic eco-neurotoxicology

During the last decade, there has been an increase in awareness of how anthropogenic pollution can alter behavioural traits of diverse aquatic organisms. Apart from understanding profound ecological implications, alterations in neuro-behavioural indices have emerged as sensitive and physiologically integrative endpoints in chemical risk assessment. Accordingly, behavioural ecotoxicology and broader eco-neurotoxicology are becoming increasingly popular fields of research that span a plethora of fundamental laboratory experimentations as well as applied field-based studies. Despite mounting interest in aquatic behavioural ecotoxicology studies, there is, however, a considerable paucity in deciphering the mechanistic foundations underlying behavioural alterations upon exposure to pollutants. The behavioural phenotype is indeed the highest-level integrative neurobiological phenomenon, but at its core lie myriads of intertwined biochemical, cellular, and physiological processes. Therefore, the mechanisms that underlie changes in behavioural phenotypes can stem among others from dysregulation of neurotransmitter pathways, electrical signalling, and cell death of discrete cell populations in the central and peripheral nervous systems. They can, however, also be a result of toxicity to sensory organs and even metabolic dysfunctions. In this critical review, we outline why behavioural phenotyping should be the starting point that leads to actual discovery of fundamental mechanisms underlying actions of neurotoxic and neuromodulating contaminants. We highlight potential applications of the currently existing and emerging neurobiology and neurophysiology analytical strategies that should be embraced and more broadly adopted in behavioural ecotoxicology. Such strategies can provide new mechanistic discoveries instead of only observing the end sum phenotypic effects.

Ginsenosides Rb1 Attenuates Chronic Social Defeat Stress-Induced Depressive Behavior via Regulation of SIRT1-NLRP3/Nrf2 Pathways

Ginsenoside Rb1, a diol-type ginseng saponin, has various positive effects on the central nervous system. This study aimed to evaluate the antidepressant effects of Rb1 on chronic social defeat stress (CSDS) induced behavioral deficits and the exact neural cascades linked with inflammatory processes. The results of behavioral tests such as social interaction, tail suspension, and forced swimming revealed that oral treatment of Rb1 (35 and 70 mg/kg) alleviates depression-like behavior. Rb1 treatment increased antioxidant enzyme activity (SOD and CAT) and reduced lipid peroxidation (LPO) content in the hippocampus. Rb1 also suppressed the production of inflammatory cytokines (TNF-α, IL-18, and IL-1β) as well as microglial activation (Iba1) in response to CSDS. Moreover, Rb1 administration considerably reduced the protein expression of NLRP3 (inflammasome) and promoted the protein expressions of Nrf2, HO-1 and Sirtuin1(SIRT1) activation in the hippocampus. Our findings showed that Rb1 effectively restores the depressive-like behavior in CSDS-induced model mice, mediated in part by the normalization of oxidative stress levels. The suppression of neuroinflammation is mediated by the regulation of SIRT1-NLRP3/Nrf2 pathways. Our results asserted that the Rb1 is a novel therapeutic candidate for treating depression.

Central Adiponectin Signaling – A Metabolic Regulator in Support of Brain Plasticity

Brain plasticity and metabolism are tightly connected by a constant influx of peripheral glucose to the central nervous system in order to meet the high metabolic demands imposed by neuronal activity. Metabolic disturbances highly affect neuronal plasticity, which underlies the prevalent comorbidity between metabolic disorders, cognitive impairment, and mood dysfunction. Effective pro-cognitive and neuropsychiatric interventions, therefore, should consider the metabolic aspect of brain plasticity to achieve high effectiveness. The adipocyte-secreted hormone, adiponectin, is a metabolic regulator that crosses the blood-brain barrier and modulates neuronal activity in several brain regions, where it exerts neurotrophic and neuroprotective properties. Moreover, adiponectin has been shown to improve neuronal metabolism in different animal models, including obesity, diabetes, and Alzheimer’s disease. Here, we aim at linking the adiponectin’s neurotrophic and neuroprotective properties with its main role as a metabolic regulator and to summarize the possible mechanisms of action on improving brain plasticity via its role in regulating the intracellular energetic activity. Such properties suggest adiponectin signaling as a potential target to counteract the central metabolic disturbances and impaired neuronal plasticity underlying many neuropsychiatric disorders.

Lipopolysaccharide-induced depression is associated with estrogen receptor-α/SIRT1/NF-κB signaling pathway in old female mice

The present study aims to investigate the influence of sex/age on depressive-like behaviors in lipopolysaccharide (LPS)-challenged mice model, and explore the underlying mechanisms. Tail suspension test and forced swimming test were used to evaluate the depressive-like behaviors. SIRT1 mRNA expression was assessed by PCR. Levels of 17β-estradiol (E2), SIRT1, NF-κB, tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) were detected by enzyme linked immunosorbent assay (ELISA). In the behavior tests, under the same LPS stimulation, significant depressive-like behavior was observed in young male mice but not in young female mice, however, female mice were more likely to be depressed than male mice in the old age. Moreover, we found age-related depression difference existed only in female mice. In the experiments of mechanism exploration in old female mice, E2 improved LPS-induced depressive-like behavior, and simultaneously elevated SIRT1 levels and downregulated expressions of NF-κB and inflammatory cytokines in the hippocampus and frontal cortex. Interestingly, ERα inhibition, not ERβ inhibition, abolished E2's function. Additionally, SIRT1 antagonist also reversed E2's effects on depressive-like behavior and the expressions of NF-κB and inflammatory cytokines. These results suggested that E2 could protect the old female mice from depression via E2/ERα/SIRT1/NF-κB signaling pathway. In other words, LPS-induced depression was associated with ER-α/SIRT1/NF-κB signaling pathway in old female mice. By comparing the results of mechanism exploration in old male mice and old female mice and the different expression levels of E2, SIRT1, NF-κB and inflammatory cytokines in young female mice and old female mice, we speculate that the age or gender-related depression difference may be associated with the different activation levels of the ERα/SIRT1/NF-κB signaling pathway.

Nicotinamide Mononucleotide Combined With Lactobacillus fermentum TKSN041 Reduces the Photoaging Damage in Murine Skin by Activating AMPK Signaling Pathway

Long-term exposure to UVB (280-320 nm) can cause oxidative skin damage, inflammatory injury, and skin cancer. Research on nicotinamide mononucleotide (NMN) and lactic acid bacteria (LAB) with regard to antioxidation, anti-inflammation, and prevention of other age-related diseases has received increasing attention. In the present study, the in vitro antioxidant analysis showed that NMN combined with Lactobacillus fermentum TKSN041 (L. fermentum TKSN041) has a high scavenging ability on hydroxyl (OH), 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt (ABTS) and 1, 1-diphenyl-2-picrylhydrazyl (DPPH), and it also possess a good total antioxidant capacity. The animal experimental results show that NMN combined with LAB maintained normal liver morphology of mice and reduced pathological damage to murine skin. NMN combined with LAB significantly increased the serum levels of total superoxide dismutase (T-SOD), catalase (CAT), and interleukin (IL)-10, but reduced the levels of malondialdehyde, advanced glycation end products, tumor necrosis factor (TNF)-α, and IL-6. NMN combined with LAB increased T-SOD, CAT, IL-10, Na⁺-K⁺-ATPase, and NAD⁺ levels in the skin, but reduced TNF-α level in the skin. NMN combined with LAB increased the mRNA expression levels of SOD1, CAT, glutathione (GSH), inhibitor of NF-κB (IκB-α), IL-10, AMP-activated protein kinase (AMPK), adaptor protein, phosphotyros ineinteraction, PH domain and leucine zipper containing 1 (APPL1), peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α), and forkhead transcription factor O (FOXO) in the skin and liver, but decreased the mRNA expression levels of nuclear factor (NF)-κBp65, TNF-α, IL-6, and rapamycin target protein (mTOR). NMN combined with LAB increased the protein expression levels of AMPK, IκB-α, SOD1, and CAT in the skin tissues and reduced protein expression of NF-κBp65. NMN combined with L. fermentum TKSN041 improved murine skin damage caused by UVB irradiation, and the protective mechanism may be related to activation of the AMPK signaling pathway. The results of this study are expected to provide a reference for preventing and the treating skin photoaging.

α-Cyperone Confers Antidepressant-Like Effects in Mice via Neuroplasticity Enhancement by SIRT3/ROS Mediated NLRP3 Inflammasome Deactivation

α-Cyperone (Cy) is a major active compound of Cyperus rotundus that has various pharmacological activities. But whether Cy possesses antidepressant effect is unknown. In this study, we exposed mice to chronic unpredictable mild stress (CUMS) with or without intervention with Cy. Our results showed that Cy significantly improved the depressive phenotypes in sucrose preference test, tail suspension test and forced swimming test. Meanwhile, increased SIRT3 expression, reduced ROS production and activated NF-κB signal were detected in the hippocampus of mice. NLRP3 inflammasome related proteins including NLRP3, ASC, Caspase-1, IL-1β, IL-18 and GSDMD-N were downregulated after Cy administration. Synaptic proteins including Synapsin-1 and PSD-95 and dendritic spine density were improved after Cy treatment. Moreover, the protective effects of Cy in CUMS mice were compromised when co-administrated with SIRT3 inhibitor 3-TYP. Taken together, these findings suggested that Cy has therapeutic potential for treating depression and that this antidepressant effect may be attributed to SIRT3 stimulated neuroplasticity enhancement by suppressing NLRP3 inflammasome.

Liuweidihuang Pill Alleviates Inflammation of the Testis via AMPK/SIRT1/NF-κB Pathway in Aging Rats

Liuweidihuang Pill (LP) is a traditional Chinese herbal formula that is often used in clinical practice to treat kidney deficiency syndrome. The present study investigated the antiaging effects of LP in a D-galactose- (D-Gal-) induced subacute aging rat model. The study also attempted to explore whether anti-inflammatory mechanisms that underpin the antiaging effects are mediated by the AMPK/SIRT1/NF-κB signaling pathway. Rats were subcutaneously injected with D-Gal at a dosage of 100 mg/kg/d for 8 weeks. Upon successful induction of aging in the rats, the animal was administered LP at 0.9 g/kg/d by gavage for 4 weeks. Proteins of the testis were subsequently examined by western blot analysis, and associated locations in the testicular tissue were determined by immunohistochemistry. We observed that LP exerted antiaging effects in aging rats following the activation of AMPK/SIRT1. It was also observed that LP inhibited the expression of NF-κB, thereby further attenuating inflammation of the testis. Therefore, LP can alleviate inflammation of the testis via the AMPK/SIRT1/NF-κB pathway in aging rats.