Melatonin protects mouse testes from palmitic acid-induced lipotoxicity by attenuating oxidative stress and DNA damage in a SIRT1-dependent manner

Particle-induced osteolysis is mediated by endoplasmic reticulum stress-associated osteoblast apoptosis

Osteoblast dysfunction plays a crucial role in periprosthetic osteolysis and aseptic loosening, and endoplasmic reticulum (ER) stress is recognized as an important causal factor of wear particle-induced osteolysis. However, the influence of ER stress on osteoblast activity during osteolysis and its underlying mechanisms remain elusive. This study aims to investigate whether ER stress is involved in the detrimental effects of wear particles on osteoblasts. Through our investigation, we observed elevated expression levels of ER stress and apoptosis markers in particle-stimulated bone specimens and osteoblasts. To probe further, we employed the ER stress inhibitor, 4-PBA, to treat particle-stimulated osteoblasts. The results revealed that 4-PBA effectively alleviated particle-induced osteoblast apoptosis and mitigated osteogenic reduction. Furthermore, our study revealed that wear particle-induced ER stress in osteoblasts coincided with mitochondrial damage, calcium overload, and oxidative stress, all of which were effectively alleviated by 4-PBA treatment. Encouragingly, 4-PBA administration also improved bone formation and attenuated osteolysis in a mouse calvarial model. In conclusion, our results demonstrate that ER stress plays a crucial role in mediating wear particle-induced osteoblast apoptosis and impaired osteogenic function. These findings underscore the critical involvement of ER stress in wear particle-induced osteolysis and highlight ER stress as a potential therapeutic target for ameliorating wear particle-induced osteogenic reduction and bone destruction.

SIRT1 activation promotes energy homeostasis and reprograms liver cancer metabolism

BACKGROUND

Cancer cells are characterized by uncontrolled cell proliferation and impaired bioenergetics. Sirtuins are a family of highly conserved enzymes that play a fundamental role in energy metabolism regulation. SIRT1, in particular, drives many physiological stress responses and metabolic pathways following nutrient deprivation. We previously showed that SIRT1 activation using SCIC2.1 was able to attenuate genotoxic response and senescence. Here, we report that in hepatocellular carcinoma (HCC) cells under glucose-deprived conditions, SCIC2.1 treatment induced overexpression of SIRT1, SIRT3, and SIRT6, modulating metabolic response.

METHODS

Flow cytometry was used to analyze the cell cycle. The MTT assay and xCELLigence system were used to measure cell viability and proliferation. In vitro enzymatic assays were carried out as directed by the manufacturer, and the absorbance was measured with an automated Infinite M1000 reader. Western blotting and immunoprecipitation were used to evaluate the expression of various proteins described in this study. The relative expression of genes was studied using real-time PCR. We employed a Seahorse XF24 Analyzer to determine the metabolic state of the cells. Oil Red O staining was used to measure lipid accumulation.

RESULTS

SCIC2.1 significantly promoted mitochondrial biogenesis via the AMPK-p53-PGC1α pathway and enhanced mitochondrial ATP production under glucose deprivation. SIRT1 inhibition by Ex-527 further supported our hypothesis that metabolic effects are dependent on SIRT1 activation. Interestingly, SCIC2.1 reprogrammed glucose metabolism and fatty acid oxidation for bioenergetic circuits by repressing de novo lipogenesis. In addition, SCIC2.1-mediated SIRT1 activation strongly modulated antioxidant response through SIRT3 activation, and p53-dependent stress response via indirect recruitment of SIRT6.

CONCLUSION

Our results show that SCIC2.1 is able to promote energy homeostasis, attenuating metabolic stress under glucose deprivation via activation of SIRT1. These findings shed light on the metabolic action of SIRT1 in the pathogenesis of HCC and may help determine future therapies for this and, possibly, other metabolic diseases.

Retinal cell-targeted liposomal ginsenoside Rg3 attenuates retinal ischemia-reperfusion injury via alleviating oxidative stress and promoting microglia/macrophage M2 polarization

Retinal ischemia-reperfusion (RIR) injury remains a major challenge that is detrimental to retinal cell survival in a variety of ocular diseases. However, current clinical treatments focus on a single pathological mechanism, making them unable to provide comprehensive retinal protection. A variety of natural products including ginsenoside Rg3 (Rg3) exhibit potent antioxidant and anti-inflammatory activities. Unfortunately, the hydrophobicity of Rg3 and the presence of various intraocular barriers limit its effective application in clinical settings. Hyaluronic acid (HA)- specifically binds to cell surface receptors, CD44, which is widely expressed in retinal pigment epithelial cells and M1-type macrophage. Here, we developed HA-decorated liposomes loaded with Rg3, termed Rg3@HA-Lips, to protect against retinal damage caused by RIR injury. Treatment with Rg3@HA-Lips significantly inhibited the oxidative stress induced by RIR injury. In addition, Rg3@HA-Lips promoted the transition of M1-type macrophage to the M2 type, ultimately reversing the pro-inflammatory microenvironment. The mechanism of Rg3@HA-Lips was further investigated and found that they can regulateSIRT/FOXO3a, NF-κB and STAT3 signaling pathways. Together with as well demonstrated good safety profiles, this CD44-targeted platform loaded with a natural product alleviates RIR injury by modulating the retinal microenvironment and present a potential clinical treatment strategy.

Menaquinone-4 prevents medication-related osteonecrosis of the jaw through the SIRT1 signaling-mediated inhibition of cellular metabolic stresses-induced osteoblast apoptosis

Long-term usage of bisphosphonates, especially zoledronic acid (ZA), induces osteogenesis disorders and medication-related osteonecrosis of the jaw (MRONJ) in patients, thereby contributing to the destruction of bone remodeling and the continuous progression of osteonecrosis. Menaquinone-4 (MK-4), a specific vitamin K2 isoform converted by the mevalonate (MVA) pathway in vivo, exerts the promotion of bone formation, whereas ZA administration suppresses this pathway and results in endogenous MK-4 deficiency. However, no study has evaluated whether exogenous MK-4 supplementation can prevent ZA-induced MRONJ. Here we showed that MK-4 pretreatment partially ameliorated mucosal nonunion and bone sequestration among ZA-treated MRONJ mouse models. Moreover, MK-4 promoted bone regeneration and inhibited osteoblast apoptosis in vivo. Consistently, MK-4 downregulated ZA-induced osteoblast apoptosis in MC3T3-E1 cells and suppressed the levels of cellular metabolic stresses, including oxidative stress, endoplasmic reticulum stress, mitochondrial dysfunction, and DNA damage, which were accompanied by elevated sirtuin 1 (SIRT1) expression. Notably, EX527, an inhibitor of the SIRT1 signaling pathway, abolished the inhibitory effects of MK-4 on ZA-induced cell metabolic stresses and osteoblast damage. Combined with experimental evidences from MRONJ mouse models and MC3T3-E1 cells, our findings suggested that MK-4 prevents ZA-induced MRONJ by inhibiting osteoblast apoptosis through suppression of cellular metabolic stresses in a SIRT1-dependent manner. The results provide a novel translational direction for the clinical application of MK-4 for preventing MRONJ.

Obese mothers supplemented with melatonin during gestation and lactation ameliorate the male offspring's pancreatic islet cellular composition and beta-cell function

Melatonin supplementation to obese mothers during gestation and lactation might benefit the pancreatic islet cellular composition and beta-cell function in male offspring adulthood. C57BL/6 females (mothers) were assigned to two groups (n = 20/each) based on their consumption in control (C 17% kJ as fat) or high-fat diet (HF 49% kJ as fat). Mothers were supplemented with melatonin (Mel) (10 mg/kg daily) during gestation and lactation, or vehicle, forming the groups (n = 10/each): C, CMel, HF, and HFMel. The male offspring were studied, considering they only received the C diet after weaning until three months old. The HF mothers and their offspring showed higher body weight, glucose intolerance, insulin resistance, and low insulin sensitivity than the C ones. However, HFMel mothers and their offspring showed improved glucose metabolism and weight loss than the HF ones. Also, the offspring's higher expressions of pro-inflammatory markers and endoplasmic reticulum (ER) stress were observed in HF but reduced in HFMel. Contrarily, antioxidant enzymes were less expressed in HF but improved in HFMel. In addition, HF showed increased beta-cell mass and hyperinsulinemia but diminished in HFMel. Besides, the beta-cell maturity and identity gene expressions diminished in HF but enhanced in HFMel. In conclusion, obese mothers supplemented with melatonin benefit their offspring's islet cell remodeling and function. In addition, improving pro-inflammatory markers, oxidative stress, and ER stress resulted in better glucose and insulin levels control. Consequently, pancreatic islets and functioning beta cells were preserved in the offspring of obese mothers supplemented with melatonin.

Protective effects of melatonin against oxidative stress induced by metabolic disorders in the male reproductive system: a systematic review and meta-analysis of rodent models

Background

Male infertility is a multifaceted issue that has gained scientific interest due to its increasing rate. Studies have demonstrated that oxidative stress is involved in male infertility development. Furthermore, metabolic disorders, including obesity, diabetes, hypo- and hyperthyroidism, are risk factors for male infertility, and oxidative stress is believed to contribute to this association. Melatonin, functioning as an oxidative scavenger, may represent a promising therapeutic approach for the prevention and treatment of metabolic disorder-associated male infertility.

Material and methods

We systematically searched three online databases (PubMed, Scopus, and Web of Science) for studies that evaluated the effects of melatonin therapy on metabolic disorders-induce infertility in male rodents. The favorable outcomes were histopathological parameters of testicular tissue, reproductive hormones, and markers of oxidative stress. Then, meta-analyses were done for each outcome. The results are reported as standardized mean difference (Cohen's d) and 95% confidence interval.

Results

24 studies with 31 outcomes were included. Rats and mice were the subjects. Studies have employed obesity, diabetes, hypothyroidism, hyperthyroidism, hyperlipidemia, and food deprivation as metabolic disorders. To induce these disorders, a high-fat diet, high-fructose diet, leptin, streptozotocin, alloxan, carbimazole, and levothyroxine were used. The outcomes included histopathologic characteristics (abnormal sperm morphology, apoptotic cells, apoptotic index, Johnsen's testicular biopsy score, seminiferous epithelial height, tubular basement membrane thickness, tubular diameter, sperm count, and motility), weight-related measurements (absolute epididymis, testis, and body weight, body weight gain, epididymal adipose tissue weight, and relative testis to body weight), hormonal characteristics (androgen receptor expression, serum FSH, LH, and testosterone level), markers of oxidative stress (tissue and serum GPx and MDA activity, tissue CAT, GSH, and SOD activity), and exploratory outcomes (serum HDL, LDL, total cholesterol, triglyceride, and blood glucose level). The overall pooled effect sizes were statistically significant for all histopathological characteristics and some markers of oxidative stress.

Conclusions

Melatonin can reduce damage to male rodents' gonadal tissue and improve sperm count, motility, and morphology in metabolic diseases. Future clinical studies and randomized controlled trials are needed to evaluate the safety and effectiveness of melatonin for male infertility in patients with metabolic diseases.

Melatonin alleviated fluoride-induced impairment of spermatogenesis and sperm maturation process via Interleukin-17A

Fluoride-induced male reproductive failure is a major environmental and human health concern, but interventions are still lacking. Melatonin (MLT) has potential functions in regulating testicular damage and interleukin-17 (IL-17) production. This study aims to explore whether MLT can mitigate fluoride-induced male reproductive toxicity through IL-17A, and screen the potential targets. So the wild type and IL-17A knockout mice were employed and treated with sodium fluoride (100 mg/L) by drinking water and MLT (10 mg/kg.BW, intraperitoneal injection per two days starting from week 16) for 18 weeks. Bone F- concentrations, grade of dental damage, sperm quality, spermatogenic cells counts, histological morphology of testis and epididymis, and the mRNA expression of spermatogenesis and maturation, classical pyroptosis related and immune factor genes were detected respectively. The results revealed that MLT supplementations alleviated fluoride-induced impairment of spermatogenesis and maturation process, protecting the morphology of testis and epididymis through IL-17A pathway, and Tesk1 and Pten were identified as candidate targets from 29 regulation genes. Taken together, this study demonstrated a new physiological role for MLT in the protection against fluoride-induced reproductive injury and possible regulation mechanisms, which providing a useful therapeutic strategy for male reproductive function failure caused by fluoride or other environmental pollutants.

Protective effects of melatonin on deoxynivalenol-induced oxidative stress and autophagy in IPEC-J2 cells

This study explored protective effects of melatonin (MEL) on deoxynivalenol (DON)-induced toxicity in porcine jejunum epithelial cells (IPEC-J2). Cells were preexposed to MEL and then exposed to DON to detect cell viability, apoptosis, and oxidative stress indicators. Compared to DON treatment, pretreatment with MEL significantly increased cell proliferation. (P < 0.01), intracellular catalase (CAT) and superoxide dismutase (SOD) levels (P < 0.05), decreased apoptosis and oxidative stress, and significantly attenuated the inflammatory response. RNA-seq analysis revealed that MEL protects IPEC-J2 from the adverse effects of DON by affecting the expression of tight junction and autophagy pathway-related genes. Similarly, further experiments revealed that MEL partly prevented DON-induced disruption of intestinal barrier function and decreased autophagy induced by DON via activation of the AKT/mTOR pathway. In conclusion, these results demonstrated the preventive properties of MEL against DON-induced cell damage by activating the antioxidant system and Inhibition of autophagy.

Mitochondrial stress in advanced fibrosis and cirrhosis associated with chronic hepatitis B, chronic hepatitis C, or nonalcoholic steatohepatitis

BACKGROUND AND AIMS

Hepatitis B virus (HBV) infection causes oxidative stress (OS) and alters mitochondria in experimental models. Our goal was to investigate whether HBV might alter liver mitochondria also in humans, and the resulting mitochondrial stress might account for the progression of fibrosis in chronic hepatitis B (CHB).

APPROACH AND RESULTS

The study included 146 treatment-naïve CHB mono-infected patients. Patients with CHB and advanced fibrosis (AF) or cirrhosis (F3-F4) were compared to patients with no/mild-moderate fibrosis (F0-F2). Patients with CHB were further compared to patients with chronic hepatitis C (CHC; n = 33), nonalcoholic steatohepatatis (NASH; n = 12), and healthy controls ( n = 24). We detected oxidative damage to mitochondrial DNA (mtDNA), including mtDNA strand beaks, and identified multiple mtDNA deletions in patients with F3-F4 as compared to patients with F0-F2. Alterations in mitochondrial function, mitochondrial unfolded protein response, biogenesis, mitophagy, and liver inflammation were observed in patients with AF or cirrhosis associated with CHB, CHC, and NASH. In vitro , significant increases of the mitochondrial formation of superoxide and peroxynitrite as well as mtDNA damage, nitration of the mitochondrial respiratory chain complexes, and impairment of complex I occurred in HepG2 cells replicating HBV or transiently expressing hepatitits B virus X protein. mtDNA damage and complex I impairment were prevented with the superoxide-scavenging Mito-Tempo or with inducible nitric oxide synthase (iNOS)-specific inhibitor 1400 W.

CONCLUSIONS

Our results emphasized the importance of mitochondrial OS, mtDNA damage, and associated alterations in mitochondrial function and dynamics in AF or cirrhosis in CHB and NASH. Mitochondria might be a target in drug development to stop fibrosis progression.

The protective role of melatonin in citalopram-induced reproductive toxicity via modulating nitro-oxidative stress and apoptosis in male mice

Citalopram is the most potent selective serotonin reuptake inhibitor, commonly prescribed as an antidepressant, which can cause sexual dysfunction. Melatonin is a natural, highly effective antioxidant playing a pivotal role in the male reproductive system. The present study aimed to explore the ameliorating potential of melatonin on citalopram-evoked testicular toxicity and injury in mice. In this regard, mice were randomly divided into six groups: control, citalopram, melatonin 10 mg/kg, melatonin 20 mg/kg, melatonin 10 mg/kg plus citalopram, and melatonin 20 mg/kg plus citalopram. Adult male mice were intraperitoneally (i.p.) injected with 10 mg/kg of citalopram for 35 days with or without melatonin. At the end of the study, sperm parameters, testosterone level, testicular levels of malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC), and apoptosis (Tunel essay) were evaluated. Our findings revealed that melatonin restored spermatogenesis by improving sperm count, motility, viability, morphology, and chromatin integrity. Testosterone levels and the histopathology of the testes were markedly improved in the melatonin-administrated groups. Furthermore, citalopram administration significantly increased oxidative stress; however, melatonin restored antioxidant status by enhancing TAC levels and decreasing NO and MAD levels. More notably, citalopram therapy induced a significant increase in the number of Tunel-positive cells, while melatonin administration significantly mitigated the apoptotic impacts of citalopram. Together, melatonin therapy provides protection against citalopram-induced testicular damage via modulating nitro-oxidative stress and apoptosis, which provides evidence for melatonin as a promising treatment against antidepressant drug-associated reproductive toxicity and male sub/infertility.

The role of ferroptosis mediated by Bmal1/Nrf2 in nicotine -induce injury of BTB integrity

Nicotine has shown the toxic effects on male reproductive system, and testicular damage is associated with ferroptosis, which is a non-apoptotic regulated cell death driven by iron-dependent lipid peroxidation. However, the role of nicotine on ferroptosis of testicular cells is largely elusive. In the present study, we showed that nicotine destroyed blood-testis barrier (BTB) by interfering with the circadian rhythm of BTB-related factors (ZO-1, N-Cad, Occludin and CX-43) and induced ferroptosis, as reflected via increased clock-control levels of lipid peroxide and decreased ferritin and GPX4, which involved in the circadian. Inhibition of ferroptosis with Fer-1 alleviated nicotine-induced injury of BTB and impaired sperm in vivo. Mechanically, we uncover that the core molecular clock protein, Bmal1, regulates the expression of Nrf2 via direct E-box binding to its promoter to regulate its activity, and nicotine decreases the transcription of Nrf2 through Bmal1 and inactivates Nrf2 pathway and its downstream antioxidant gene, which leads to the imbalance of redox state and ROS accumulation. Intriguingly, nicotine induced lipid peroxidation and subsequent ferroptosis by Bmal1-mediated Nrf2. In conclusion, our study reveals a clear role for the molecular clock in controlling Nrf2 in testis to mediate the ferroptosis induced by nicotine. These findings provide a potential mechanism to prevent smoking and/or cigarette smoke-induced male reproductive injury.

Advances in circadian clock regulation of reproduction

The mammalian circadian clock is an endogenously regulated oscillator that is synchronized with solar time and cycle within a 24-h period. The circadian clock exists not only in the suprachiasmatic nucleus (SCN) of the hypothalamus, a central pacemaker of the circadian clock system, but also in numerous peripheral tissues known as peripheral circadian oscillators. The SCN and peripheral circadian oscillators mutually orchestrate the diurnal rhythms of various physiological and behavioral processes in a hierarchical manner. In the past two decades, peripheral circadian oscillators have been identified and their function has been determined in the mammalian reproductive system and its related endocrine glands, including the hypothalamus, pituitary gland, ovaries, testes, uterus, mammary glands, and prostate gland. Increasing evidence indicates that both the SCN and peripheral circadian oscillators play discrete roles in coordinating reproductive processes and optimizing fertility in mammals. The present study reviews recent evidence on circadian clock regulation of reproductive function in the hypothalamic-pituitary-gonadal axis and reproductive system. Additionally, we elucidate the effects of chronodisruption (as a result of, for example, shift work, jet lag, disrupted eating patterns, and sleep disorders) on mammalian reproductive performance from multiple aspects. Finally, we propose potential behavioral changes or pharmaceutical strategies for the prevention and treatment of reproductive disorders from the perspective of chronomedicine. Conclusively, this review will outline recent evidence on circadian clock regulation of reproduction, providing novel perspectives on the role of the circadian clock in maintaining normal reproductive functions and in diseases that negatively affect fertility.

SIRT1/PGC-1α is involved in arsenic-induced male reproductive damage through mitochondrial dysfunction, which is blocked by the antioxidative effect of zinc

Exposure to arsenic poses threats to male reproductive system, including impairing the testes and sperm quality. Although an association regarding arsenic exposure and male reproductive damage has been reported, the undergoing molecular mechanisms and interventions for prevention remain unclear. For the present work, male mice were exposed to 0, 2.5, 5, or 10 ppm sodium arsenite (NaAsO₂) for 8 months. The results showed that arsenic-exposed mice had reduced fertility with abnormalities in the testes, epididymides, and sperm. Exposure of mice to arsenic caused a redox imbalance, decreased SIRT1 and PGC-1α levels, and affected mitochondrial biogenesis and proteins related to mitochondrial dynamics. For immortalized spermatogenic (GC-2) cells, arsenic caused apoptosis and oxidative stress, reduced SIRT1/PGC-1α levels and ATP production, inhibited mitochondrial respiration, and changed the mitochondrial membrane potential (MMP). Mitochondrial biogenesis and dynamics were also impaired. However, by reducing mitochondrial damage in GC-2 cells, upregulation of SIRT1 or zinc (Zn) supplementation reversed the apoptosis induced by arsenic. For mice, Zn supplementation blocked arsenic-induced oxidative stress, the decreases of SIRT1 and PGC-1α levels, and the impairment of mitochondrial function, and it reversed the damage to testes, low sperm quality, and low litter size. Collectively, these results suggest that arsenic causes excessive production of ROS, inhibits the SIRT1/PGC-1α pathway, and causing mitochondrial dysfunction by mediating impairment of mitochondrial biogenesis and dynamics, which results in germ cells apoptosis and male reproductive damage, processes that are blocked by Zn via an antioxidative effect. Our study contributes to understanding of the mechanisms for arsenic-induced male reproductive damage and points to the therapeutic significance of Zn.

Deciphering the Role of Melatonin-Related Signatures in Tumor Immunity and the Prognosis of Clear Cell Renal Cell Carcinoma

Methods

Adopting multiomics data from TCGA and other public datasets, we analysed the expression, mutation, and prognostic evaluation in multiple cancers. ccRCC patients were categorized into two subgroups by an unsupervised cluster algorithm: melatonin-pattern cancer subtype 1 (MPCS1) and subtype 2 (MPCS2). We then explored the immune microenvironment, immune therapy response, and tumor metabolic pathways between the two subtypes. The clinical characteristics, genomic mutation landscape, and molecular inhibitor response were further investigated. Finally, a melatonin regulator-related prognostic model was constructed to predict patient prognosis in ccRCC.

Results

We found that melatonin regulators were dysregulated depending on distinct cancer types, which were associated with genomic variation. The two subtypes indicated different clinical characteristics and biological processes in ccRCC. MPCS2, an aggressive subtype, led an advanced clinical stage and poorer survival of ccRCC patients. The activated oncogenic signaling pathway and metabolic signatures were responsible for cancer progression in the MPCS2 subtype. The MPCS2 subgroup suggested a higher tumor mutational burden and immune dysfunction state, resulting in a lower response to immunotherapy. The copy number variations of MPCS2 were significantly more frequent than those of MPCS1. In addition, the two subgroups exhibited distinct drug responsiveness, with MPCS2 being less responsive to multiple drugs. Finally, we established a subtype biomarker-based prognostic risk model that exhibited satisfactory performance in ccRCC patients.

Conclusion

Melatonin regulator-related features could remodel functional pathways and the tumor immune microenvironment through genomic mutations and pathway regulation. Melatonin regulator-associated molecular subtypes enhance the understanding of the molecular characteristics of renal cancer and can guide clinical treatment. Activating the melatonergic system axis may improve the effect of immunotherapy for ccRCC.

Melatonin Ameliorates Diquat-Induced Testicular Toxicity via Reducing Oxidative Stress, Inhibiting Apoptosis, and Maintaining the Integrity of Blood-Testis Barrier in Mice

Diquat is a fast, potent, and widely used bipyridine herbicide in agriculture and it induces oxidative stress in several animal models. However, its genotoxic effects on the male reproductive system remain unclear. Melatonin is an effective free-radical scavenger, which has antioxidant and anti-apoptotic properties and can protect the testes against oxidative damage. This study aimed to investigate the therapeutic effects of melatonin on diquat-induced testicular injury in mice. The results showed melatonin treatment alleviated diquat-induced testicular injury, including inhibited spermatogenesis, increased sperm malformations, declined testosterone level and decreased fertility. Specifically, melatonin therapy countered diquat-induced oxidative stress by increasing production of the antioxidant enzymes GPX1 and SOD1. Melatonin treatment also attenuated diquat-induced spermatogonia apoptosis in vivo and in vitro by modulating the expression of apoptosis-related proteins, including P53, Cleaved-Caspase3, and Bax/Bcl2. Moreover, melatonin restored the blood-testicular barrier by promoting the expression of Sertoli cell junction proteins and maintaining the ordered distribution of ZO-1. These findings indicate that melatonin protects the testes against diquat-induced damage by reducing oxidative stress, inhibiting apoptosis, and maintaining the integrity of the blood-testis barrier in mice. This study provides a theoretical basis for further research to protect male reproductive health from agricultural pesticides.

Cellular senescence of renal tubular epithelial cells in renal fibrosis

Renal fibrosis (RF) is the common pathological manifestation of virtually all chronic kidney diseases (CKD) and one of the major causes of end-stage renal disease (ESRD), but the pathogenesis of which is still unclear. Renal tubulointerstitial lesions have been identified as a key pathological hallmark of RF pathology. Renal tubular epithelial cells are the resident cells of the tubulointerstitium and play an important role in kidney recovery versus renal fibrosis following injury. Studies in recent years have shown that senescence of renal tubular epithelial cells can accelerate the progression of renal fibrosis. Oxidative stress(OS), telomere attrition and DNA damage are the major causes of renal tubular epithelial cell senescence. Current interventions and therapeutic strategies for cellular senescence include calorie restriction and routine exercise, Klotho, senolytics, senostatics, and other related drugs. This paper provides an overview of the mechanisms and the key signaling pathways including Wnt/β-catenin/RAS, Nrf2/ARE and STAT-3/NF-κB pathway involved in renal tubular epithelial cell senescence in RF and therapies targeting renal tubular epithelial cell senescence future therapeutic potential for RF patients. These findings may offer promise for the further treatment of RF and CKD.

Adenovirus-mediated SIRT1 protects cochlear strial marginal cells in a D-gal-induced senescent model in vitro

BACKGROUND

A primary obstacle in age-related hearing loss (ARHL) study is the lack of accelerated senescent models in vitro that explore the precise underlying mechanism in different types of ARHL. The damage to strial marginal cells (SMCs) is a subset of strial presbycusis-associated pathological changes. We aimed to establish a D-galactose (D-gal)-induced SMCs senescent model and study the effect of deacetylase sirtuin 1 (SIRT1) on presbycusis in vitro.

METHODS

SMCs from C57BL/6J neonatal mice were cultured and treated with D-gal to establish accelerated senescent models. And then D-gal-induced SMCs were transfected with adenovirus (Ad)-SIRT1-GFP or Ad-GFP. Oxidative stress and mitochondrial DNA (mtDNA) damage were determined by histological analysis or RT-PCR. Western blotting (WB) and RT-PCR were used to evaluate protein and mRNA levels of superoxide dismutase 2 (SOD2) and SIRT1, respectively. Additionally, apoptosis was investigated by WB and TUNEL staining.

RESULTS

D-gal-induced SMCs exhibited several characteristics of senescence, including increased the level of 8-hydroxy-2'-deoxyguanosine, which is a marker of DNA oxidative damage, and elevated the amount of mtDNA 3860-bp deletion, which is a common type of mtDNA damage in the auditory system of mice. SIRT1 overexpression effectively inhibited these changes by upregulating the level of SOD2, thereby inhibiting cytochrome c translocation from mitochondria to cytoplasm, inhibiting cell apoptosis, and ultimately delaying aging in the D-gal-induced senescent SMCs.

CONCLUSIONS

Altogether, the evidence suggests that the D-gal-induced SMCs accelerated aging model is successfully established, and SIRT1 overexpression protects SMCs against oxidative stress by enhancing SOD2 expression in ARHL.

ROS/ER stress contributes to trimethyltin chloride-mediated hepatotoxicity; Tea polyphenols alleviate apoptosis and immunosuppression

Trimethyltin chloride (TMT) is an organotin-based contaminant present in the water environment that poses a great threat to aquatic organisms and humans. The liver is the detoxification organ of the body and TMT exposure accumulates in the liver. Tea polyphenol (TP) is a natural antioxidant extracted from tea leaves and has been widely used as a food and feed additive. To investigate the mechanism of toxicity caused by TMT exposure on grass carp hepatocytes (L8824 cells) and the mitigating effect of TP, we established a hepatocyte model of TMT toxicity and/or TP treatment. L8824 cells were treated with 0.5 μM of TMT and/or 4 μg/mL of TP for 24 h and assayed for relevant indices. The results showed that TMT exposure caused oxidative stress, resulting in increased intracellular ROS content, resulting in intracellular ROS accumulation and increased MDA content, and inhibiting the activities of T-AOC, SOD, CAT, and GSH. Meanwhile, TMT exposure activated the endoplasmic reticulum apoptotic signaling pathway, resulting in abnormal expression of GRP78, ATF-6, IRE1, PERK, Caspase-3 and Caspase-12. In addition, TMT exposure also led to up-regulation of cytokines IL-1β, IL-6, TNF-α, and decreased expression of IL-2, IFN-γ, and antimicrobial peptides Hepcidin, β-defensin, and LEAP2. However, the addition of TP could mitigate the above changes. In conclusion, TP can alleviate TMT exposure-mediated hepatotoxicity by inhibiting ROS/ER stress in L8824 cells. In addition, this trial enriches the cytotoxicity study of TMT and provides a new theoretical basis for the use of TP as a mitigating agent for TMT.

Amelioratory Effect of Melatonin on Cognition Dysfunction Induced by Sevoflurane Anesthesia in Aged Mice

Background

Postoperative cognitive dysfunction (POCD) can be described as a clinical phenomenon characterized by cognitive impairment in patients, particularly elderly patients, after anesthesia and surgery. Researchers have focused on the probable effect of general anesthesia drugs on cognitive functioning status in older adults. Melatonin is an indole-type neuroendocrine hormone with broad biological activity and potent anti-inflammatory, anti-apoptotic, and neuroprotective effects. This study investigated the effects of melatonin on cognitive behavior in aged mice anesthetized with sevoflurane. In addition, melatonin's molecular mechanism was determined.

Objectives

This study aimed to investigate the mechanisms of melatonin against sevoflurane-induced neurotoxicity.

Methods

A total of 94 aged C57BL/6J mice were categorized into different groups, namely control (control + melatonin (10 mg/kg)), sevoflurane (sevoflurane + melatonin (10 mg/kg)), sevoflurane + melatonin (10 mg/kg) + phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) inhibitor LY294002 (30 mg/kg), and sevoflurane + melatonin (10 mg/kg) + mammalian target of rapamycin (mTOR) inhibitor (10 mg/kg). The open field and Morris water maze tests were utilized to assess the neuroprotective effects of melatonin on sevoflurane-induced cognitive impairment in aged mice. The expression levels of the apoptosis-linked proteins, PI3K/Akt/mTOR signaling pathway, and pro-inflammatory cytokines in the brain's hippocampus region were determined using the Western blotting technique. The apoptosis of the hippocampal neurons was observed using the hematoxylin and eosin staining technique.

Results

Neurological deficits in aged, sevoflurane-exposed mice were significantly decreased after melatonin treatment. Mechanistically, melatonin treatment restored sevoflurane-induced down-regulated PI3K/Akt/mTOR expression and significantly attenuated sevoflurane-induced apoptotic cells and neuroinflammation.

Conclusions

The findings of this study have highlighted the neuroprotective effect of melatonin on sevoflurane-induced cognitive impairment via regulating the PI3K/Akt/mTOR pathway, which might be effective in the clinical treatment of elderly patients with anesthesia-induced POCD.

Engineered Extracellular Vesicles with SHP2 High Expression Promote Mitophagy for Alzheimer's Disease Treatment

Mitochondrial dysfunction is a fundamental pathological feature of Alzheimer's disease (AD). However, toxicity and poor brain enrichment of existing mitophagy inducers limit their further applications. In this study, a platform for AD therapy is developed using nanosized mesenchymal-stem-cells-derived extracellular vesicles with tyrosine phosphatase-2 (SHP2) high-expression (MSC-EVs-SHP2). The high blood-brain barrier penetration ability of MSC-EVs-SHP2 is demonstrated in AD-mice, facilitating SHP2 delivery to the brain. In addition, MSC-EVs-SHP2 significantly induces mitophagy of neuronal cells, which alleviates mitochondrial damage-mediated apoptosis and NLRP3 inflammasome activation. Mitophagy further diminishes neuronal cells apoptosis and neuroinflammation, culminating with rescued synaptic loss and cognitive decline in an AD mouse model. The EV-engineering technology provides a potential platform for effective AD therapy by inducing mitophagy.

Melatonin suppresses bone marrow adiposity in ovariectomized rats by rescuing the imbalance between osteogenesis and adipogenesis through SIRT1 activation

INTRODUCTION

Accelerated imbalance between bone formation and bone resorption is associated with bone loss in postmenopausal osteoporosis. Studies have shown that this loss is accompanied by an increase in bone marrow adiposity. Melatonin was shown to improve impaired bone formation capacity of bone marrow-derived mesenchymal stem cells from ovariectomized rats (OVX-BMMSCs).

OBJECTIVES

To investigate whether the anti-osteoporosis effect of melatonin involves regulation of the equilibrium between osteogenic and adipogenic differentiation of osteoporotic BMMSCs.

METHODS

To induce osteoporosis, female Sprague-Dawley rats received ovariectomy (OVX). Primary BMMSCs were isolated from tibiae and femurs of OVX and sham-op rats and were induced towards osteogenic or adipogenic differentiation. Matrix mineralization was determined by Alizarin Red S (ARS) and lipid formation was evaluated by Oil Red O. OVX rats were injected with melatonin through the tail vein. Bone microarchitecture was determined using micro computed tomography and marrow adiposity were examined by histology staining.

RESULTS

OVX-BMMSCs exhibited a compromised osteogenic potential and an enhanced lineage differentiation towards adipocytes. In vitro melatonin improved osteogenic differentiation of OVX-BMMSCs and promoted matrix mineralization by enhancing the expression of transcription factor RUNX2 in a dose-dependent manner. Moreover, melatonin significantly inhibited lipid formation and suppressed OVX-BMMSCs adipogenesis by down-regulating peroxisome proliferator-activated receptor γ (PPARγ). Intravenous injection of melatonin prevented bone mass reduction and bone architecture destruction in ovariectomized rats. Importantly, there was a significant inhibition of adipose tissue formation in the bone marrow. Mechanistic investigations revealed that SIRT1 was involved in melatonin-mediated determination of stem cell fate. Inhibition of SIRT1 abolished the protective effects of melatonin on bone formation by inducing BMMSCs towards adipocyte differentiation.

CONCLUSIONS

Melatonin reversed the differentiation switch of OVX-BMMSCs from osteogenesis to adipogenesis by activating the SIRT1 signaling pathway. Restoration of stem cell lineage commitment by melatonin prevented marrow adipose tissue over-accumulation and protected from bone loss in postmenopausal osteoporosis.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Determination of stem cell fate towards osteoblasts or adipocytes plays a pivotal role in regulating bone metabolism. This study demonstrates the protective effect of melatonin on bone mass in estrogen-deficient rats by suppressing adipose tissue accumulation in the bone marrow. Melatonin may serve as a promising candidate for the treatment of osteoporosis in clinics.

Taxifolin increased semen quality of Duroc boars by improving gut microbes and blood metabolites

Taxifolin (TAX), as a natural flavonoid, has been widely focused on due to its strong anti-oxidation, anti-inflammation, anti-virus, and even anti-tumor activity. However, the effect of TAX on semen quality was unknown. The purpose of this study was to analyze the beneficial influences of adding feed additive TAX to boar semen in terms of its quality and potential mechanisms. We discovered that TAX increased sperm motility significantly in Duroc boars by the elevation of the protein levels such as ZAG, PKA, CatSper, and p-ERK for sperm quality. TAX increased the blood concentration of testosterone derivatives, antioxidants such as melatonin and betaine, unsaturated fatty acids such as DHA, and beneficial amino acids such as proline. Conversely, TAX decreased 10 different kinds of bile acids in the plasma. Moreover, TAX increased “beneficial” microbes such as Intestinimonas, Coprococcus, Butyrivibrio, and Clostridium_XlVa at the Genus level. However, TAX reduced the “harmful” intestinal bacteria such as Prevotella, Howardella, Mogibacterium, and Enterococcus. There was a very close correlation between fecal microbes, plasma metabolites, and semen parameters by the spearman correlation analysis. Therefore, the data suggest that TAX increases the semen quality of Duroc boars by benefiting the gut microbes and blood metabolites. It is supposed that TAX could be used as a kind of feed additive to increase the semen quality of boars to enhance production performance.

Melatonin Prevents against Ethanol-Induced Liver Injury by Mitigating Ferroptosis via Targeting Brain and Muscle ARNT-like 1 in Mice Liver and HepG2 Cells

The circadian clock acts a pivotal part in human daily physiology and metabolism. Excess alcohol consumption disturbs the circadian rhythm of several metabolism-related genes of the liver. Melatonin is a member of the foremost hormones secreted by the pineal gland with numerous pharmacological properties in quite a number of diseases. However, its potential roles and possible mechanisms in ethanol-induced ferroptosis are still not clear completely. Ethanol feeding studies were performed upon a chronic-plus-binge ethanol feeding protocol in C57BL/6 mice with or without intraperitoneal injection administration of melatonin. HepG2 cells and mice primary hepatocytes were subjected to investigation for ethanol and melatonin. The results showed that melatonin dramatically ameliorated liver injury and decreased ferroptosis makers induced by ethanol. Meanwhile, melatonin effectively reversed the circadian misalignment caused by ethanol. Additionally, melatonin accelerated Nrf2 nuclear translocation and further activated its downstream anti-ferroptosis proteins including FTH, FPN, HO-1, and SLC7A11 in ethanol-changed mice liver tissues and HepG2 cells. However, the impact of melatonin on liver protection and anti-ferroptosis was offset upon brain and muscle ARNT-like 1 (BMAL1) knockdown with the notably blocked Nrf2-ARE pathway. Altogether, this study revealed that melatonin could alleviate ethanol-induced liver injury by impeding ferroptosis via reprogramming the circadian protein BMAL1 and subsequently activating the Nrf2-ARE anti-ferroptosis pathway. The emergence of novel liver protective effects and mechanism of melatonin on ethanol-induced ferroptosis may provide a new dimension for prevention or intervention against liver injury associated with ethanol.

Orientin downregulating oxidative stress-mediated endoplasmic reticulum stress and mitochondrial dysfunction through AMPK/SIRT1 pathway in rat nucleus pulposus cells in vitro and attenuated intervertebral disc degeneration in vivo

Although considered as a major contributor to low back pain (LBP), intervertebral disc degeneration (IVDD) has poor medical and surgical treatments. Various studies have revealed that endoplasmic reticulum (ER) stress and extracellular matrix (ECM) degeneration play a vital role in initiating and developing the progression of IVDD. Moreover, restoration of SIRT1/AMPK was confirmed to prevent IVDD and damage via maintaining ER and extracellular homeostasis. In addition, orientin (Ori) has been shown to upregulate SIRT1. However, the effect of Ori in nucleus pulposus cells (NPCs) is not determined. Hence, in this study we aim to explore the function of Ori in IVDD pathological model. The results demonstrate that Ori treatment in vitro increased SIRT1/AMPK in NPCs, maintained ECM and ER balance and decreased oxidative stress (OS) response. Ori rescued the disordered homeostasis stimulated by tert-butyl hydroperoxide (TBHP), and its function can be inhibited by thapsigargin (TG). Compound C and EX-527, inhibitors of AMPK and SIRT1 counteracted the Ori-mediated ER stress elimination. These results confirm that Ori exerts its effects by upregulating AMPK and SIRT1. Puncture-stimulated IVDD rats were used to show that Ori attenuates the pathological development in vivo. In all, we partly unveil the underlying mechanisms of Ori in IVDD.

Sirtuins as novel pharmacological targets in podocyte injury and related glomerular diseases

Podocyte injury is a major cause of proteinuria in kidney diseases, and persistent loss of podocytes leads to rapid irreversible progression of kidney disease. Sirtuins, a class of nicotinamide adenine dinucleotide-dependent deacetylases, can promote DNA repair, modify transcription factors, and regulate the cell cycle. Additionally, sirtuins play a critical role in renoprotection, particularly against podocyte injury. They also have pleiotropic protective effects on podocyte injury-related glomerular diseases, such as improving the immune inflammatory status and oxidative stress levels, maintaining mitochondrial homeostasis, enhancing autophagy, and regulating lipid metabolism. Sirtuins deficiency causes podocyte injury in different glomerular diseases. Studies using podocyte sirtuin-specific knockout and transgenic models corroborate this conclusion. Of note, sirtuin activators have protective effects in different podocyte injury-related glomerular diseases, including diabetic kidney disease, focal segmental glomerulosclerosis, membranous nephropathy, IgA nephropathy, and lupus nephritis. These findings suggest that sirtuins are promising therapeutic targets for preventing podocyte injury. This review provides an overview of recent advances in the role of sirtuins in kidney diseases, especially their role in podocyte injury, and summarizes the possible rationale for sirtuins as targets for pharmacological intervention in podocyte injury-related glomerular diseases.

Phosphoproteomics reveals that cinobufotalin promotes intrahepatic cholangiocarcinoma cell apoptosis by activating the ATM/CHK2/p53 signaling pathway

Intrahepatic cholangiocarcinoma (ICC) is a malignant tumor that originates from bile duct’s epithelial cells and is usually characterized by insidious symptoms and poor prognosis. Cinobufotalin (CB), an active ingredient obtained from the Traditional Chinese Medicine ChanSu, is purported to exhibit a wide range of antitumorigenic activities. However, the mechanism by which it achieves such pharmacological effects remains elusive. Here, we disclosed the mechanism of action by which CB inhibits ICC cells. Initial experiments revealed that the proliferation of RBE and HCCC-9810 cells was significantly inhibited by CB with IC50 values of 0.342 μM and 0.421 μM respectively. CB induced the expression of caspase-3 subsequently leading to the apoptosis of ICC cells. Phosphoproteomics revealed that the phosphorylation of many proteins associated with DNA damage response increased. Kinase-substrate enrichment analysis revealed that ATM was activated after CB treatment, while CDK1 was inactivated. Activated ATM increased p-CHK2-T68 and p-p53-S15, which promoted the expression of FAS, DR4 and DR5 and triggered cell apoptosis. In summary, this work reveals the role of CB in inducing DNA damage and cell apoptosis involved in the activation of the ATM/CHK2/p53 signaling pathway, and indicates that CB may serve as a chemotherapeutic drug candidate for ICC treatment.

Recharge of chondrocyte mitochondria by sustained release of melatonin protects cartilage matrix homeostasis in osteoarthritis

Recent evidence indicates that the mitochondrial functions of chondrocytes are impaired in the pathogenesis of osteoarthritis (OA). Melatonin can attenuate cartilage degradation through its antioxidant functions. This study aims to investigate whether melatonin could rescue the impaired mitochondrial functions of OA chondrocytes and protect cartilage metabolism. OA chondrocytes showed a compromised matrix synthesis capacity associated with mitochondrial dysfunction and aberrant oxidative stress. In vitro treatments with melatonin promoted the expression of cartilage extracellular matrix (ECM) components, improved adenosine triphosphate production, and attenuated mitochondrial oxidative stress. Mechanistically, either silencing of SOD2 or inhibition of SIRT1 abolished the protective effects of melatonin on mitochondrial functions and ECM synthesis. To achieve a sustained release effect, a melatonin-laden drug delivery system (DDS) was developed and intra-articular injection with DDS successfully improved cartilage matrix degeneration in a posttraumatic rat OA model. These findings demonstrate that melatonin-mediated recharge of mitochondria to rescue the mitochondrial functions of chondrocytes represents a promising therapeutic strategy to protect cartilage from OA.

Ligustilide Improves Cognitive Impairment via Regulating the SIRT1/IRE1α/XBP1s/CHOP Pathway in Vascular Dementia Rats

Vascular dementia (VaD), the second cause of dementia, is caused by chronic cerebral hypoperfusion, producing progressive damage to cerebral cortex, hippocampus, and white matter. Ligustilide (LIG), one of the main active ingredients of Angelica sinensis, exerts the neuroprotective effect on neurodegenerative diseases. However, the mechanism remains unclear. An in vivo model of bilateral common carotid artery occlusion and in vitro model of oxygen glucose deprivation (OGD) were employed in this study. LIG (20 or 40 mg/kg/day) was intragastrically administered to the VaD rats for four weeks. The results of the Morris water maze test demonstrated that LIG effectively ameliorated learning and memory deficiency in VaD rats. LIG obviously relieved neuronal oxidative stress damage by increasing the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) and decreasing the level of malondialdehyde (MDA) in VaD rats. Nissl staining showed that LIG increased the number of the Nissl body in VaD rats. After LIG administration, the apoptotic-related protein, Bax, was decreased and Bcl-2 was increased in the hippocampus of VaD rats. Moreover, the expressions of sirtuin 1 (SIRT1) and protein disulfide isomerase (PDI) were decreased, binding immunoglobulin protein (BIP) and phospho-inositol-requiring enzyme-1α (P-IRE1α), X-box binding protein 1 (XBP1s), and C/EBP-homologous protein (CHOP) were increased in VaD rats. After LIG treatment, these changes were reversed. The immunofluorescence results further showed that LIG upregulated the expression of SIRT1 and downregulated the expression of P-IRE1α in VaD rats. In addition, in vitro experiment showed that EX-527 (SIRT1 inhibitor) partly abolished the inhibitory effect of LIG on the IRE1α/XBP1s/CHOP pathway. In conclusion, these studies indicated that LIG could improve cognitive impairment by regulating the SIRT1/IRE1α/XBP1s/CHOP pathway in VaD rats.

Melatonin ameliorates diabetic hyperglycaemia-induced impairment of Leydig cell steroidogenic function through activation of SIRT1 pathway

BACKGROUND

Diabetes mellitus (DM)-related complications are important health problems worldwide. The underlying mechanisms for diabetic male subfertility/infertility are considerably complicated and need to be unveiled for therapeutic intervention. Melatonin treatment was investigated to assess the beneficial effects on injured steroidogenic function in DM due to its regulatory roles in mitochondria and autophagy.

METHODS

Diabetic hyperglycaemia was induced in rats injected with streptozotocin (STZ, 55 mg/kg/d) or simulated in TM3 Leydig cell line cultured with medium containing 30 mM D-glucose. Then, diabetic rats or the TM3 cells under high glucose were treated with melatonin. The diabetic rats were randomly divided into diabetes mellitus group (DM group), insulin treatment group (DM + INS group) and melatonin treatment group (DM + MT group). The TM3 Leydig cells were divided into a normal glucose control group (NG group), a high glucose treatment group (HG group), and a melatonin treatment group (HG + MT group). Then, Sirt1 (silent mating type information regulation 2 homologue) 1 expression was knocked down by siRNA.

RESULTS

The results showed that hyperglycaemia induced a decline in steroidogenesis, accompanied by autophagy defects, mitochondrial dysfunction and oxidative stress, in rats in the DM group or TM3 Leydig cells in the HG group. Furthermore, reduced SIRT1 expression levels and hyperacetylation were found in Leydig cells of DM group. Melatonin treatment ameliorated hyperglycaemia-induced impairment of Leydig cell function with simultaneous stimulation of 5'-adenosine monophosphate activated protein kinase (AMPK)/SIRT1 activity and the expression of autophagy-related genes. With regards to mitochondrial function, it promoted mitochondrial biogenesis with elevated PGC-1α, NRF1 and mtTFA, improved mitochondrial morphology, increased BNIP3L-related mitophagy and alleviated oxidative stress. Further results revealed that knockdown of Sirt1 in Leydig cells prevented the protective effects provided by melatonin against high glucose treatment, and interestingly, neutralization of reactive oxygen species (ROS) by N-acetyl-L-cysteine pretreatment abolished the stimulatory effect of melatonin on AMPK/SIRT1 activity in Leydig cells and prevented the induction of autophagy and mitochondrial biogenesis in the context of high glucose, indicating that modulation of SIRT1 pathway by melatonin was closely linked to ROS levels and oxidative stress.

CONCLUSIONS

These findings suggest that SIRT1 pathway plays essential roles in the pleiotropic actions of melatonin on Leydig cells and in the prevention of hyperglycaemia-induced steroidogenic dysfunction. The stimulatory action of melatonin on SIRT1 pathway is related to oxidative stress and its antioxidant property. Our data provide new evidence for the relationship of melatonin and SIRT1 pathway in the context of hyperglycaemia, and melatonin as a combination therapy may be useful to combat DM-related complications, especially male reproductive system injury.

Melatonin ameliorates renal dysfunction in glyphosate- and hard water-treated mice

Chronic interstitial nephritis in agricultural communities (CINAC) is a severe and widespread disease that has been associated with environmental and occupational exposure to glyphosate and hard water. However, the potential underlying mechanisms remain incompletely understood. Melatonin is reported to exert protective effects on the kidney, but whether melatonin can attenuate renal tubular injury in mice exposed to glyphosate combined with hard water is unclear. Here, mice were treated with high doses and environmentally relevant doses of glyphosate (100 mg/kg·bw and 0.7 mg/L, respectively) and/or hard water (2500 mg/L CaCO₃ and 250 mg/L Ca²⁺, respectively) via their drinking water for 12 weeks. We found that high-dose glyphosate or hard water treatment significantly increased the levels of biomarkers of renal damage, including β₂-microglobulin, neutrophil gelatinase-associated lipid carrier protein, and/or albumin, in the urine; these increased biomarker levels were correlated with obvious morphological changes, and all of these changes were also observed in animals exposed to environmentally relevant doses of glyphosate and/or high Ca²⁺ water. Melatonin (10 mg/kg·bw, intraperitoneal injection, daily for 12 weeks) administered concomitantly with high doses of glyphosate and hard water inhibited the glyphosate- and hard water-induced increases in the levels of kidney injury biomarkers and changes in morphology; this result was intriguing. Additionally, glyphosate combined with hard water at both high and environmentally relevant doses significantly upregulated the expression of the endoplasmic reticulum (ER) stress marker proteins Bip, ATF6, and PERK as well as the pyroptosis-related proteins (NLRP3 and caspase 1 signaling proteins) in renal tissues. Similarly, melatonin significantly attenuated the increased ER stress and pyroptosis induced by high doses of glyphosate and hard water. In summary, we conclude that exposure to glyphosate and hard water at both high doses and environmentally relevant doses causes renal dysfunction in mice, and this dysfunction can be attenuated by melatonin, possibly through the inhibition of ER stress and pyroptosis. Our results support the notion that melatonin may have therapeutic potential for the treatment of chronic kidney diseases.

Protective effect of melatonin on alleviating early oxidative stress induced by DOX in mice spermatogenesis and sperm quality maintaining

Doxorubicin (DOX) is an effective chemotherapy drug, but its clinical use has adverse effects on male reproduction. However, there are few studies about the specific biological processes related to male reproduction or strategies for improving fertility protection. In this paper, we examined the effects of DOX on spermatogenesis and sperm function, and tested the possible protective role of melatonin (MLT) against DOX's reproductive toxicity. DOX-treated mice showed signs of significantly impaired spermatogenesis, including vacuolated epithelial cells, decreased testis weights, and lowered sperm counts and motility. DOX also reduced germ cell proliferation (PCNA) and meiosis-related proteins (SYCP3), but this effect could be partially improved with MLT administration. HSPA2 expression was maintained, which indicated that although MLT did not improve sperm motility, it did have a significant protective effect on elongated sperm. IVF results showed that MLT could partially promote two-cell and blastocyte development that was restricted by DOX. MLT reversed DOX-driven changes in the testes, including the antioxidant indices of SOD1, CAT and PRDX6, and the apoptotic indices of BAX and Caspase3. These results suggest that MLT effectively prevents DOX-induced early reproductive toxicity, and increase our understanding of the molecular mechanisms underlying DOX's effects on male reproduction and the protective mechanism of MLT.

Melatonin supplementation preserves testicular function by attenuating lactate production and oxidative stress in high fat diet-induced obese rat model

Metabolic syndrome, including obesity has been documented as a critical factor in male reproductive dysfunction with subsequent reduction in male fertility. The therapeutic potential of melatonin has been demonstrated against oxidative stress-induced pathologies. Therefore, the present study investigated the effects of melatonin on testicular dysfunction associated with high fat diet (FD)-induced obese rat model, and the possible involvement of peroxisome proliferator-activated receptor-γ (PPAR-γ). Adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% FD, melatonin-treated group received melatonin (4 mg/kg), and obese plus melatonin group received melatonin and 40% FD and the treatment lasted for 12 weeks. High fat diet caused increased body weight and testicular triglyceride, total cholesterol, malondialdehyde, γ-glutamyl transferase, lactate production and lactate/pyruvate ratio as well as decreased glutathione/glutathione peroxidase, nitric oxide and PPAR-γ and circulating testosterone. Nevertheless, all these alterations were attenuated when supplemented with melatonin. Taken together, these results demonstrates that FD-induced obesity causes testicular dysfunction. In addition, the results suggest that melatonin supplementation protects against obesity-associated testicular dysfunction and this effect is accompanied by upregulation of PPAR-γ.

Endoplasmic reticulum stress and mitochondrial injury are critical molecular drivers of AlCl3-induced testicular and epididymal distortion and dysfunction: protective role of taurine

Aluminum, the third most plentiful metal in the Earth's crust, has potential for human exposure and harm. Oxidative stress plays an essential role in producing male infertility by inducing defects in sperm functions. We aimed to investigate the role of endoplasmic reticulum (ER) stress and mitochondrial injury in the pathogenesis of aluminum chloride (AlCl3)-induced testicular and epididymal damage at the histological, biochemical, and molecular levels, and to assess the potential protective role of taurine. Forty-eight adult male albino rats were separated into four groups (12 in each): negative control, positive control, AlCl3, and AlCl3 plus taurine groups. Testes and epididymis were dissected. Histological and immunohistochemical (Bax and vimentin) studies were carried out. Gene expression of vimentin, PCNA, CHOP, Bcl-2, Bax, and XBP1 were investigated via quantitative real-time polymerase chain reaction (qRT-PCR), besides estimation of malondialdehyde (MDA) and total antioxidant capacity (TAC). Light and electron microscopic examinations of the testes and epididymis revealed pathological changes emphasizing both mitochondrial injury and ER stress in the AlCl3 group. Taurine-treated rats showed a noticeable improvement in the testicular and epididymal ultrastructure. Moreover, they exhibited increased gene expression of vimentin, Bcl-2, and PNCA accompanied by decreased CHOP, Bax, and XBP1 gene expression. In conclusion, male reproductive impairment is a significant hazard associated with AlCl3 exposure. Both ER stress and mitochondrial impairment are critical mechanisms of the deterioration in the testes and epididymis induced by AlCl3, but taurine can amend this.

Fullerenol protects cornea from ultraviolet B exposure

The eyes are highly susceptible to the oxidative stress induced by ultraviolet B (UVB, wavelength between 280 ∼ 320 nm), which could cause severe damage to the cornea. Fullerenols are effective antioxidants to alleviate UVB-induced injury, while their application for the eyes is still rare. In present study, we investigated the protective performance and mechanism of fullerenols on cornea under UVB radiation in vivo and in vitro. The synthesized fullerenols exhibited broad-spectrum free radical scavenging properties (applicable to both reactive oxygen species (ROS) and reactive nitrogen species (RNS)) and photo-stability. When compared with another widely used antioxidant glutathione (GSH), the administration of fullerenols markedly decreased the injured area, corneal edema, cell death, and increased the cell proliferation in UVB-induced rat cornea. The effects of fullerenols were confirmed in UVB-exposed human corneal epithelial cells (hCECs), where elevated cell viability and proliferation, decreased oxidative free radical production, repaired mitochondrial dysfunction and DNA lesions were observed. RNA sequencing (RNA-Seq) analysis demonstrated that fullerenol alleviated UVB-induced corneal injury through down-regulation of oxidative stress-related genes and up-regulation of proliferation-associated genes. Our results demonstrate the suitability of fullerenols as a potential exogenous treatment in ameliorating UVB-induced cornea damage.

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Fullerenol produces significant precaution on UVB-induced corneal damage.

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Fullerenol exhibits broader spectrum free radical scavenging properties than GSH.

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Fullerenol mitigates the LSCs loss in the cornea caused by UVB.

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Fullerenol down-regulates oxidative stress genes and up-regulates proliferation-related genes.

Activation of MT1/MT2 to Protect Testes and Leydig Cells against Cisplatin-Induced Oxidative Stress through the SIRT1/Nrf2 Signaling Pathway

There is growing concern that chemotherapy drugs can damage Leydig cells and inhibit the production of testosterone. Increasing evidence shows that melatonin benefits the reproductive process. This study mainly explores the protective effect and possible molecular mechanism of melatonin regarding cisplatin-induced oxidative stress in testicular tissue and Leydig cells. We found that there were only Leydig and Sertoli cells in the testes of gastrointestinal tumor patients with azoospermia caused by platinum chemotherapeutic drugs. Melatonin (Mel) receptor 1/melatonin receptor 2 (MT1/MT2) was mainly expressed in human and mouse Leydig cells of the testes. We also observed that the melatonin level in the peripheral blood decreased and oxidative stress occurred in mice treated with cisplatin or gastrointestinal tumor patients treated with platinum-based chemotherapeutic drugs. iTRAQ proteomics showed that SIRT1/Nrf2 signaling and MT1 proteins were downregulated in cisplatin-treated mouse testes. The STRING database predicted that MT1 might be able to regulate the SIRT1/Nrf2 signaling pathway. Melatonin reduced oxidative stress and upregulated SIRT1/Nrf2 signaling in cisplatin-treated mouse testes and Leydig cells. Most importantly, after inhibiting MT1/MT2, melatonin could not upregulate SIRT1/Nrf2 signaling in cisplatin-treated Leydig cells. The MT1/MT2 inhibitor aggravated the cisplatin-induced downregulation of SIRT1/Nrf2 signaling and increased the apoptosis of Leydig cells. We believe that melatonin stimulates SIRT1/Nrf2 signaling by activating MT1/MT2 to prevent the cisplatin-induced apoptosis of Leydig cells.

Melatonin relieves 2,2,4,4-tetrabromodiphenyl ether (BDE-47)-induced apoptosis and mitochondrial dysfunction through the AMPK-Sirt1-PGC-1α axis in fish kidney cells (CIK)

Polybrominated diphenyl ethers (PBDEs) exist in aquatic environments with nephrotoxicity to non-target aquatic species. Melatonin (MT) exhibits an inhibitory effect of oxidative stress and apoptosis in various diseases. 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) is the main homolog of PBDE samples. Therefore, we investigated the toxic mechanism of BDE-47 and the alleviation effect of MT, the ctenopharyngodon idellus kidney (CIK) cells were treated with BDE-47 (100 μM) and/or MT (60 μM) for 24 h. Firstly, BDE-47 exposure could inhibit oxidative stress-related antioxidant enzymes (T-AOC, SOD, CAT and GPx) and increase the content of malondialdehyde (MDA) to cause oxidative stress. Secondly, BDE-47 enhanced mitochondrial division and inhibited fusion to induce mitochondrial membrane potential in CIK cells. BDE-47 enhanced the mRNA and protein levels of mitochondrial-pathway apoptosis related genes (Cas 3, Cyt-c, and BAX). Thirdly, BDE-47 treatment decreased the expression levels of mitochondrial-related regulatory factors AMPK-Sirt1-PGC-1α signal pathway. Intriguingly, BDE-47-induced oxidative stress, mitochondrial pathway apoptosis and mitochondrial dynamics disorder could be alleviated by MT treatment. Overall, we concluded that MT could relieve BDE-47-induced oxidative stress, mitochondrial dysfunction and apoptosis through the AMPK-Sirt1-PGC-1α axis. These results enrich the mechanisms of BDE-47 poisoning and reveal that MT treatment may be a potential strategy for solving BDE-47 poisoning.

Environmental cadmium impairs blood-testis barrier via activating HRI-responsive mitochondrial stress in mice

Cadmium (Cd) is a well-known testicular toxicant. Blood-testis barrier (BTB), a vital part of testes, which has been reported to be damaged upon Cd exposure. However, the detailed mechanism about Cd-mediated disruption of BTB remains unclear. This study aims to investigate the role of Heme-Regulated Inhibitor (HRI)-responsive mitochondrial stress in Cd-mediated disruption of BTB. Male mice are intraperitoneally injected (i.p.) with melatonin (Mel, a cellular stress antagonist, 5.0 mg/kg) before Cd treatment (i.p., 2.0 mg/kg) for 8 h, and then treated with Cd for 0-48 h. Mouse Sertoli cells are pretreated with Mel (10 μM) for 1 h, and then treated with Cd (10 μM) for 0-24 h. We find that Cd damages the BTB and reduces the Occludin protein, a crucial BTB-related protein via activating p38/matrix metalloproteinase-2 (p38/MMP2) pathway and Integrated Stress Response (ISR). Further experiments reveal that the Heme-Regulated Inhibitor (HRI)-responsive mitochondrial stress is triggered in Cd-treated Sertoli cells. Most importantly, Cd-activated p38 signaling and ISR are regulated by HRI-responsive mitochondrial stress in Sertoli cells. Unexpectedly, we find that melatonin rescues the Cd-mediated disruption of BTB through blocking HRI-responsive mitochondrial stress in testes. Overall, these data indicate that environmental cadmium exposure impairs the BTB through activating HRI-responsive mitochondrial stress in Sertoli cells.

Metabolomics-Based Frailty Biomarkers in Older Chinese Adults

Background/Objectives

Owing to accelerated population aging, health in older adults is becoming increasingly important. Frailty can reflect the health status and disease risks of older adults; however, appropriate biomarkers for early screening of frailty have not been identified. Here, we applied metabolomics to identify frailty biomarkers and potential pathogenic mechanisms of frailty.

Methods

Serum metabolic profiles from 25 frail and 49 non-frail (control) older adults were systematically investigated by liquid chromatography-mass spectrometry-based metabolomics.

Results

We identified 349 metabolites of 46 classes, with four increased and seven decreased metabolites in frail older adults. Pearson correlation analysis identified 11 and 21 metabolites that were positively and negatively correlated with grip strength, and 7 and 76 metabolites that were positively and negatively correlated with gait speed, respectively. Pathway analysis identified 10 metabolite sets and 13 pathways significantly associated with one or more frailty phenotype criteria.

Conclusion

These results revealed the metabolite characteristics of serum in frail older adults. Intermediates of carbohydrate metabolism (e.g., isocitrate, malate, fumarate, cis-aconitate, glucuronate, and pyruvate), saturated fatty acids (e.g., palmitic acid), unsaturated fatty acids (e.g., arachidonate and linoleic acid), and certain essential amino acids (e.g., tryptophan) may be candidate biomarkers for the early diagnosis of frailty. Mitochondrial function disorders, saturated fatty acid-mediated lipotoxicity, aberrant unsaturated fatty acid metabolism, and increased tryptophan degradation could be potential mechanisms of frailty.

Melatonin and the Programming of Stem Cells

Melatonin interacts with various types of stem cells, in multiple ways that comprise stimulation of proliferation, maintenance of stemness and self-renewal, protection of survival, and programming toward functionally different cell lineages. These various properties are frequently intertwined but may not be always jointly present. Melatonin typically stimulates proliferation and transition to the mature cell type. For all sufficiently studied stem or progenitor cells, melatonin’s signaling pathways leading to expression of respective morphogenetic factors are discussed. The focus of this article will be laid on the aspect of programming, particularly in pluripotent cells. This is especially but not exclusively the case in neural stem cells (NSCs) and mesenchymal stem cells (MSCs). Concerning developmental bifurcations, decisions are not exclusively made by melatonin alone. In MSCs, melatonin promotes adipogenesis in a Wnt (Wingless-Integration-1)-independent mode, but chondrogenesis and osteogenesis Wnt-dependently. Melatonin upregulates Wnt, but not in the adipogenic lineage. This decision seems to depend on microenvironment and epigenetic memory. The decision for chondrogenesis instead of osteogenesis, both being Wnt-dependent, seems to involve fibroblast growth factor receptor 3. Stem cell-specific differences in melatonin and Wnt receptors, and contributions of transcription factors and noncoding RNAs are outlined, as well as possibilities and the medical importance of re-programming for transdifferentiation.

Cordyceps cicadae Ameliorates Renal Hypertensive Injury and Fibrosis Through the Regulation of SIRT1-Mediated Autophagy

Hypertensive renal injury is a complication of hypertension. Cordyceps cicadae (C. cicadae) is a traditional Chinese medicine used to treat chronic kidney diseases especially renal fibrosis. Autophagy is described as a cell self-renewal process that requires lysosomal degradation and is utilized for the maintenance of cellular energy homeostasis. The present study explores the mechanism underlying C. cicadae’s renoprotection on hypertensive nephropathy (HN). First, HN rat models were established on spontaneously hypertensive rats (SHRs). The expression of fibrosis-related protein and autophagy-associated protein was detected in vivo. NRK-52E cells exposed to AngII were chosen to observe the potential health benefits of C. cicadae on renal damage. The level of extracellular matrix accumulation was detected using capillary electrophoresis immunoquantification and immunohistochemistry. After treatment with lysosomal inhibitors (chloroquine) or an autophagy activator (rapamycin), the expression of Beclin-1, LC3II, and SQSTM1/p62 was further investigated. The study also investigated the change in sirtuin1 (SIRT1), fork head box O3a (FOXO3a), and peroxidation (superoxide dismutase (SOD) and malondialdehyde (MDA)) expression when intervened by resveratrol. The changes in SIRT1 and FOXO3a were measured in patients and the SHRs. Here, we observed that C. cicadae significantly decreased damage to renal tubular epithelial cells and TGFβ1, α-smooth muscle actin (α-SMA), collagen I (Col-1), and fibronectin expression. Meanwhile, autophagy defects were observed both in vivo and in vitro. C. cicadae intervention significantly downregulated Beclin-1 and LC3II and decreased SQSTM1/p62, showing an inhibition of autophagic vesicles and the alleviation of autophagy stress. These functions were suppressed by rapamycin, and the results were just as effective as the resveratrol treatment. HN patients and the SHRs exhibited decreased levels of SIRT1 and FOXO3a. We also observed a positive correlation between SIRT1/FOXO3a and antifibrotic effects. Similar to the resveratrol group, the expression of SIRT1/FOXO3a and oxidative stress were elevated by C. cicadae in vivo. Taken together, our findings show that C. cicadae ameliorates tubulointerstitial fibrosis and delays HN progression. Renoprotection was likely attributable to the regulation of autophagic stress mediated by the SIRT1 pathway and achieved by regulating FOXO3a and oxidative stress.

LncRNA Tug1 maintains blood-testis barrier integrity by modulating Ccl2 expression in high-fat diet mice

Sertoli cells are essential for spermatogenesis in the testicular seminiferous tubules by forming blood-testis barrier (BTB) and creating a unique microenvironment for spermatogenesis. Many lncRNAs have been reported to participate in spermatogenesis. However, the role of long noncoding RNAs (lncRNAs) in Sertoli cells has rarely been examined. Herein, we found that a high-fat diet (HFD) decreased sperm quality, impaired BTB integrity and resulted in accumulation of saturated fatty acids (SFAs), especially palmitic acid (PA), in mouse testes. PA decreased the expression of tight junction (TJ)-related proteins, increased permeability and decreased transepithelial electrical resistance (TER) in primary Sertoli cells and TM4 cells. Moreover, lncRNA Tug1 was found to be involved in PA-induced BTB disruption by RNA-seq. Tug1 depletion distinctly impaired the TJs of Sertoli cells and overexpression of Tug1 alleviated the disruption of BTB integrity induced by PA. Moreover, Ccl2 was found to be a downstream target of Tug1, and decreased TJ-related protein levels and TER and increased FITC-dextran permeability in vitro. Furthermore, the addition of Ccl2 damaged BTB integrity after overexpression of Tug1 in the presence of PA. Mechanistically, we found that Tug1 could directly bind to EZH2 and regulate H3K27me3 occupancy in the Ccl2 promoter region by RNA immunoprecipitation and chromatin immunoprecipitation assays. Our study revealed an important role of Tug1 in the BTB integrity of Sertoli cells and provided a new view of the role of lncRNAs in male infertility.

Mechanisms of Melatonin in Obesity: A Review

Obesity and its complications have become a prominent global public health problem that severely threatens human health. Melatonin, originally known as an effective antioxidant, is an endogenous hormone found throughout the body that serves various physiological functions. In recent decades, increasing attention has been paid to its unique function in regulating energy metabolism, especially in glucose and lipid metabolism. Accumulating evidence has established the relationship between melatonin and obesity; nevertheless, not all preclinical and clinical evidence indicates the anti-obesity effect of melatonin, which makes it remain to conclude the clinical effect of melatonin in the fight against obesity. In this review, we have summarized the current knowledge of melatonin in regulating obesity-related symptoms, with emphasis on its underlying mechanisms. The role of melatonin in regulating the lipid profile, adipose tissue, oxidative stress, and inflammation, as well as the interactions of melatonin with the circadian rhythm, gut microbiota, sleep disorder, as well as the α7nAChR, the opioidergic system, and exosomes, make melatonin a promising agent to open new avenues in the intervention of obesity.

Evidence of melatonin ameliorative effects on the blood-testis barrier and sperm quality alterations induced by cadmium in the rat testis

Herein, we further document the protective action of melatonin (MLT) in mitigating cadmium (Cd) effects on adult rat testis. Cd treatment provoked testicular injury, that was documented by histological and biomolecular alterations, i.e., decrease of serum and testicular testosterone concentration and modified sperm parameters. Mainly, both the cytoarchitecture of the blood-testis barrier (BTB) and germ cell morphology were perturbed, as highlighted by impairment in structural (OCN, VANGL, Cx43) and regulative (Src and FAK) protein levels and/or activation. The study focused on the involvement of the autophagy pathway, that was enhanced especially in the Sertoli cells, probably in response to the disorganization of the BTB. Results obtained with the MLT co-treatment demonstrated that its administration decreased the level of oxidative damage caused by Cd, with reversal of all the observed changes. Moreover, the beneficial effects of MLT alone were evidenced by an increase of sperm quality, in term of motility and DNA integrity. The combined results, obtained in rat, strongly encourage to consider a role for MLT in improving also human testicular health, not only in men exposed to Cd, but also in those having fertility disorders, to ameliorate sperm quality and, consequently, reproductive success.

Acetate supplementation restores testicular function by modulating Nrf2/PPAR-γ in high fat diet-induced obesity in Wistar rats

Purpose

Several studies have established impaired testicular function in obese male population, including the young males with childhood obesity, contributing to increased male infertility, which is a universal trend in the last few decades. Short chain fatty acids (SCFAs) have been recently demonstrated to inhibit progression to metabolic comorbidities. The present study therefore hypothesized that SCFAs, acetate attenuates testicular dysfunction in high fat diet (HFD)-induced obese rat model, possibly by modulating Nrf2/PPAR-γ.

Methods

Adult male Wistar rats weighing 160-190 g were randomly allotted into three groups (n = 6/group): The groups received vehicle (distilled water), 40% HFD and sodium acetate (200 mg/kg) plus 40% HFD respectively. The administration lasted for 12 weeks.

Results

HFD caused obesity, which is characterized with increased body weight and visceral adiposity and insulin resistance/hyperinsulinemia. In addition, it increased testicular lipid deposition, malondialdehyde, pro-inflammatory mediators, lactate/pyruvate ratio, γ-Glutamyl transferase, and circulating leptin as well as decreased testicular glutathione, nitric oxide, Nrf2, PPAR-γ and circulating follicle stimulating hormone and testosterone without a significant change in testicular lactate dehydrogenase, blood glucose and luteinizing hormone when compared to the control group. Nevertheless, administration of acetate reversed the HFD-induced alterations.

Conclusion

The present results demonstrates that HFD causes obesity-driven testicular dysfunction, associated with testicular lipid deposition, oxidative stress, and inflammation. The study in addition suggests the restoration of testicular function in obese animals by acetate, an effect that is accompanied by elevated Nrf2/PPAR-γ.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.

SAA1 is transcriptionally activated by STAT3 and accelerates renal interstitial fibrosis by inducing endoplasmic reticulum stress

Renal interstitial fibrosis (RIF) is the common irreversible pathway by which chronic kidney disease (CKD) progresses to the end stage. The transforming growth factor-β (TGF-β)/signal transducer and activator of transcription 3 (STAT3) signaling pathway is a common factor leading to inflammation-mediated RIF, but its downstream regulatory mechanism is still unclear. Bioinformatics analysis predicted that serum amyloid A protein 1 (SAA1) was one of the target genes for transcriptional activation of STAT3 signaling. As an acute phase reaction protein, SAA1 plays an important role in many inflammatory reactions, and research has suggested that SAA1 is significantly elevated in the serum of patients with CKD. In this research, multiple experiments were performed to investigate the role of SAA1 in the process of RIF. SAA1 was abnormally highly expressed in kidney tissue from individuals who underwent unilateral ureteral obstruction (UUO) and TGF-β-induced HK2 cells, and the abnormal expression was directly related to the transcriptional activation of STAT3. Additionally, SAA1 can directly target and bind valosin-containing protein (VCP)-interacting membrane selenoprotein (VIMP) to inhibit the function of the Derlin-1/VCP/VIMP complex, preventing the transportation and degradation of the misfolded protein, resulting in endoplasmic reticulum (ER) stress characterized by an increase in glucose-regulated protein 78 (GRP78) levels and ultimately promoting the occurrence and development of RIF.

Melatonin regulates proliferation and apoptosis of endometrial stromal cells via MT1

Endometrial dysfunction is an important factor for implantation failure. The function of the endometrium is regulated by multiple factors like sex hormones and circadian rhythms. Endometrial stromal cells (ESCs) are a major cellular component in the endometrium, which is essential for proper physiological activities of the endometrium and the establishment of pregnancy. Melatonin, as a circadian-controlled hormone, plays beneficial roles in the regulation of reproductive processes. MT1, a melatonin receptor, can regulate cell proliferation and apoptosis. Whether melatonin-MT1 signal affects biological function of ESCs remains unknown. Here, we showed that MT1 was expressed in human ESCs (hESCs), which could be regulated by estrogen and progesterone. MT1 knockdown inhibited proliferative activity and promoted apoptosis of hESCs by activating caspase-3 and upregulating the Bax/Bcl2 ratio. Melatonin could reverse the effect of MT1 knockdown on proliferative activity and apoptosis of hESCs. Melatonin could promote proliferative activity of hESCs via the JNK/P38 signal pathway and repress the apoptosis of hESCs via the JNK signal pathway. Moreover, in vivo experiments showed that MT1 expression was decreased in endometrial cells from mice with disrupted circadian rhythm, accompanied by increased apoptosis and suppressed proliferative activity, which could be alleviated by administration of melatonin. These results showed the regulatory effect of melatonin-MT1 signal on biological behaviors of ESCs, which might provide a novel therapeutic strategy for endometrial dysfunction induced by disrupted circadian rhythm.

γ-Linolenic Acid Prevents Lipid Metabolism Disorder in Palmitic Acid-Treated Alpha Mouse Liver-12 Cells by Balancing Autophagy and Apoptosis via the LKB1-AMPK-mTOR Pathway

Excessive fat deposition is the main character in nonalcoholic fatty liver disease (NAFLD), while γ-linolenic acid (GLA) is a polyunsaturated fatty acid that can reduce lipid deposition. This study investigated the effect and regulatory mechanism of GLA (100 μM) on lipid metabolism in alpha mouse liver 12 (AML-12) cells treated by 400 μM palmitic acid (PA). GLA reduced lipid content and increased fatty acid β oxidation, as indicated by decreasing triglyceride and cholesterol contents and increasing mRNA and protein expressions of CPT1α and PPARα. GLA relieved oxidative stress caused by PA, upregulated mRNA levels of superoxide dismutase and glutathione peroxidase, and decreased reactive oxygen species content. GLA reduced apoptosis, as indicated by decreases in the BAX/BCL2 expression level and apoptosis percentage. GLA activated autophagy, autophagosome-lysosome fusion, and LKB1-AMPK-mTOR signaling and upregulated mRNA and protein expressions of Beclin-1, autophagy-related 5, and liver kinase B1 (LKB1). These effects of GLA on lipid metabolism disorders of PA-treated hepatocytes were reversed by autophagy inhibitor 3MA and AMPK inhibitor compound C, confirming our conclusions. Overall, GLA can protect AML-12 cells from lipid metabolism disorder caused by PA via balancing autophagy and apoptosis mediated by the LKB1-AMPK-mTOR pathway. Consequently, GLA, as a dietary supplement, can help to prevent and treat NAFLD by regulating lipid metabolism and autophagy.

Research progress of melatonin (MT) in improving ovarian function: a review of the current status

Melatonin (MT) is an endogenous hormone mainly synthesized by pineal cells, which has strong endogenous effects of eliminating free radicals and resisting oxidative damages. Melatonin (MT) can not only regulate the body’s seasonal and circadian rhythms; but also delay ovarian senescence, regulate ovarian biological rhythm, promote follicles formation, and improve oocyte quality and fertilization rate. This review aimd to provide evidence concerning the synthesis and distribution, ovarian function, and role of MT in development of follicles and oocytes. Moreover, the role of MT as antioxidative, participating in biological rhythm regulation, was also reviewed. Furthermore, the effects of MT on various ovarian related diseases were analyzed, particularly for the ovarian aging and polycystic ovary syndrome (PCOS).