Melatonin protects against cadmium-induced oxidative stress via mitochondrial STAT3 signaling in human prostate stromal cells

Melatonin Repairs the Lipidome of Human Hepatocytes Exposed to Cd and Free Fatty Acid-Induced Lipotoxicity

Hepatocyte lipotoxicity is central to the aetiology of nonalcoholic fatty liver disease (NAFLD), a leading cause of liver failure and transplantation worldwide. Long-lasting toxic pollutants have increasingly been considered as environmental risk factors of NAFLD. These include cadmium (Cd), a metal that synergizes with other cellular toxicants and metabolic stimuli to induce fat build-up and lipotoxicity. Recent studies demonstrated that melatonin (MLT) holds great potential as repairing agent in this form of hepatocyte lipotoxicity. In this study, the molecular hints of this MLT effect were investigated by lipidomics analysis in undifferentiated HepaRG cells, a human pre-hepatocyte cell line, exposed to Cd toxicity either alone or combined with prototypical free fatty acids (FFA), namely the saturated species palmitic acid and the monounsaturated oleic acid (OA and PA, respectively), to simulate the cellular lipotoxicity conditions of fatty liver disease. Cd exposure synergized with FFAs to induce cellular steatosis, and PA produced higher levels of lipotoxicity compared to OA by leading to increased levels of H2O2 production and apoptotic death. These effects were associated with changes of the cellular lipidome, which approximate those of NAFLD liver, with differentially expressed lipids in different classes that included triacylglycerols (TG), di- and mono-acylglycerols, phospholipids (PL), sphingolipids, acylcarnitines and FA; characteristic differences were observed in all these classes comparing the combinations of Cd exposure with PA or OA treatments. MLT significantly reduced the effects of either individual or combinatorial treatments of Cd and FFAs on lipotoxicity hallmarks, also repairing most of the alterations of the cellular lipidome, including those of the chain length and number of double bonds of acyl residues esterified to TG and PL classes. These findings and their bioinformatics interpretation suggest a role for the earliest acyl elongase and desaturase steps of FA metabolism in this repairing effect of MLT; biochemistry studies validated such interpretation identifying a specific role for SCD1 activity. This lipidomics study shed light on the cytoprotective mechanism of MLT in Cd and FFA-induced hepatocyte lipotoxicity, highlighting a repairing effect of this molecule on the cellular lipidome, which may hold therapeutic potential in fatty liver diseases.

Melatonin Improves Lactational Bisphenol S Induced Pre-Pubertal and Pubertal Testicular Impairments in Offspring

Lactational period is of extreme importance for nourishing and fostering growth in neonates. Bisphenol S (BPS) a congener of bisphenol A (BPA) is an emerging environmental toxicant reported to have deleterious effects on reproductive health. Indirect exposure of BPS to the suckling infants via breastmilk is less explored although it can lead to various public health issues. Therefore, we investigated harmful effects of lactational BPS exposure on pre-pubertal and pubertal testicular functions of the offspring and its possible amelioration by melatonin. Lactating dams were divided into 4 groups: control, melatonin treated (3 mg/kg BW), BPS treated (150 mg/kg BW) and BPS + melatonin co-treatment; the male offspring were evaluated at pre-pubertal (PND 22) and pubertal (PND 42) testicular developmental stages. Lactational BPS exposure affected testicular physiology, led to histological abnormalities, hormonal imbalance, alters blood-testis-barrier (E-cadherin/connexin-43), redox modulators (SIRT-1/FOXO-1/PGC-1α; Nrf2/HO-1/pSTAT-3) and germ cell dynamicity (PCNA/TUNEL positive cells) in both pre-pubertal and pubertal mice. However, melatonin supplementation to BPS exposed lactating mothers improved testicular histoarchitecture in offspring, enhanced testicular antioxidant status, modulated expression of redox/survival and BTB markers that promoted germ cell proliferation. In conclusion, our study shows that lactational BPS exposure could be deleterious to testicular physiology that may result in male infertility/subfertility in later life while melatonin supplementation improves the reproductive health compromised by lactational BPS exposure.

Melatonin protects against cadmium-induced endoplasmic reticulum stress and ferroptosis through activating Nrf2/HO-1 signaling pathway in mice lung

Cadmium (Cd) is a prevalent heavy metal pollutant known to cause lung damage. However, the mechanisms underlying Cd-induced lung injury and the associated therapeutic strategies remain unclear. By establishing Cd-induced lung damage models both in vivo and in vitro, we observed that Cd inhibited the Nrf2/HO-1 signaling pathway, disrupted the redox balance in lung tissue, accelerated endoplasmic reticulum (ER) stress, and promoted ferroptosis, ultimately leading to lung injury. Melatonin (Mel), a potent reactive oxygen species (ROS) inhibitor with high antioxidative efficacy, mitigated the increasing in ROS and the decreasing in superoxide dismutase levels induced by Cd, as well as the upregulation of PERK-eIF2α-ATF4 signaling associated with ER stress, through the activation of the Nrf2/HO-1 signaling pathway. Furthermore, Mel administration not only prevented Cd-induced iron overload but also reduced lipid peroxidation levels, thereby improving mitochondrial morphological alterations. Collectively, our results demonstrated that Mel treatment alleviated Cd-induced lung injury by inhibiting oxidative stress, which in turn ameliorated ER stress and ferroptosis through the activation of the Nrf2/HO-1 pathway.

Cadmium-induced iron dysregulation contributes to functional impairment in brain endothelial cells via the ferroptosis pathway

Cadmium (Cd2+) is a heavy metal that is a major hazardous environmental contaminant, ubiquitously present in the environment. Cd2+ exposure has been closely associated with an increased prevalence and severity of neurological and cardiovascular diseases (CVD). The blood-brain barrier (BBB) plays a crucial role in protecting the brain from external environmental factors. Mitochondria play an important role in maintaining the barrier function of brain endothelial cells by regulating energy metabolism and redox homeostasis. In this study, we aimed to assess the cytotoxic effects of Cd2+ on the integrity and function of brain endothelial cells. After 24 h of exposure, Cd2+ reduced cell survival, tight junction protein expression, and trans-endothelial electrical resistance (TEER) in bEnd.3 cells suggest a potential BBB integrity disruption by Cd2+ exposure. To clarify the underlying mechanism, we further investigated the role of mitochondria in iron overload-mediated cell death following Cd2+ exposure. Cd2+ induced a substantial reduction in mitochondrial basal respiration and ATP production in brain endothelial cells, suggesting mitochondrial dysfunction. In addition, Cd2+ exposure led to impaired autophagy, elevated iron levels, and increased lipid peroxidation, indicating the initiation of ferroptosis, a form of cell death triggered by iron. In summary, our research suggests that Cd2+ exposure can disrupt BBB function by causing mitochondrial dysfunction and disrupting iron homeostasis.

The Detoxification Effects of Melatonin on Aflatoxin-Caused Toxic Effects and Underlying Molecular Mechanisms

Aflatoxins (AFTs) are a form of mycotoxins mainly produced by Aspergillus flavus and Aspergillus parasiticus, which are common contaminants in various agricultural sources such as feed, milk, food, and grain crops. Aflatoxin B1 (AFB1) is the most toxic one among all AFTs. AFB1 undergoes bioactivation into AFB1-8,9-epoxide, then leads to diverse harmful effects such as neurotoxicity, carcinogenicity, hepatotoxicity, reproductive toxicity, nephrotoxicity, and immunotoxicity, with specific molecular mechanisms varying in different pathologies. The detoxification of AFB1 is of great importance for safeguarding the health of animals and humans and has increasingly attracted global attention. Recent research has shown that melatonin supplementation can effectively mitigate AFB1-induced multiple toxic effects. The protection mechanisms of melatonin involve the inhibition of oxidative stress, the upregulation of antioxidant enzyme activity, the reduction of mitochondrial dysfunction, the inactivation of the mitochondrial apoptotic pathway, the blockade of inflammatory responses, and the attenuation of cytochrome P450 enzymes' expression and activities. In summary, this review sheds new light on the potential role of melatonin as a potential detoxifying agent against AFB1. Further exploration of the precise molecular mechanisms and clinical efficacy of this promising treatment is urgently needed.

Ellagic Acid Reduces Cadmium Exposure-Induced Apoptosis in HT22 Cells via Inhibiting Oxidative Stress and Mitochondrial Dysfunction and Activating Nrf2/HO-1 Pathway

Exposure to cadmium sulfate (CdSO4) can lead to neurotoxicity. Nevertheless, the precise molecular mechanisms underlying this phenomenon remain unclear, and effective treatment strategies are scarce. This study explored the protective effects of ellagic acid (EA), a natural polyphenolic compound, against CdSO4 exposure-induced neurotoxicity in HT22 cells and the underlying molecular mechanisms. Our findings demonstrated that exposure of HT22 cells to CdSO4 resulted in apoptosis, which was effectively reversed by EA in a dose-dependent manner. EA supplementation also decreased reactive oxygen species (ROS) and mitochondrial ROS production, reduced malondialdehyde (MDA) levels, and restored the activities of superoxide dismutase (SOD) and catalase (CAT). Additionally, EA supplementation at 5-20 μM significantly counteracted Cd-induced the loss of mitochondrial membrane potential and the decrease of ATP and reduced the ratio of Bax/Bcl-2 and cleaved-caspase-3 protein expression. Furthermore, EA supplementation resulted in the upregulation of Nrf2 and HO-1 protein and mRNAs while simultaneously downregulating the phosphorylation of JNK and p38 proteins. The pharmacological inhibition of c-Jun N-terminal kinase (JNK) partially attenuated the activation of the Nrf2/HO-1 pathway induced by CdSO4 and exacerbated its cytotoxic effects. In conclusion, our findings suggest that ethyl acetate (EA) supplementation offers protective effects against CdSO4-induced apoptosis in HT22 cells by inhibiting oxidative stress and activating the Nrf2 signaling pathway. Furthermore, the activation of the JNK pathway appears to play a protective role in CdSO4-induced apoptosis in HT22 cells.

Photoperiod and metabolic health: evidence, mechanism, and implications

Circadian rhythms are evolutionarily programmed biological rhythms that are primarily entrained by the light cycle. Disruption of circadian rhythms is an important risk factor for several metabolic disorders. Photoperiod is defined as total duration of light exposure in a day. With the extended use of indoor/outdoor light, smartphones, television, computers, and social jetlag people are exposed to excessive artificial light at night increasing their photoperiod. Importantly long photoperiod is not limited to any geographical region, season, age, or socioeconomic group, it is pervasive. Long photoperiod is an established disrupter of the circadian rhythm and can induce a range of chronic health conditions including adiposity, altered hormonal signaling and metabolism, premature ageing, and poor psychological health. This review discusses the impact of exposure to long photoperiod on circadian rhythms, metabolic and mental health, hormonal signaling, and ageing and provides a perspective on possible preventive and therapeutic approaches for this pervasive challenge.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

SIRT1 regulates osteoblast senescence through SOD2 acetylation and mitochondrial dysfunction in the progression of Osteoporosis caused by Cadmium exposure

Environmental Cadmium (Cd) is a toxicant with widespread exposure, documented adverse effects on bone homeostasis, and makes the onset of osteoporosis (OP), one of the age-related chronic diseases an enormous burden to modern societies worldwide. Aging is the largest risk factor for a multitude of age-related diseases and osteoblasts senescence reduces bone formation and is a key factor for osteoporosis. Despite anti-aging molecules the nuclear silent information regulator of transcription 1 (SIRT1) actions in chondrocytes and bone cells are critical for normal skeletal development and homeostasis, much less is known about the role of SIRT1 in osteoporosis. Here, we aim to demonstrate that SIRT1 mediates osteoblasts' senescence response to OP caused by Cd. The senescent osteoblasts accumulation and their viability were analyzed after Cd exposure. To explore the effects and mechanism of SIRT1 in Cd-induced osteoblastic senescence, we generated SIRT1-overexpressed osteoblast and SIRT1 conditional overexpression in the rat femur. Meanwhile, the OP rat model was established by removing bilateral ovaries. We found decreased SIRT1 expression and senescent osteoblasts accumulation after Cd exposure. Meanwhile, Cd exposure increased P53, P16INK4a, and P21CIPI proteins level, triggered DNA damage response (DDR) through the phosphorylation of ATM and H2AX, and caused mitochondrial dysfunction by the increased acetylation of SOD2 and excessive mitophagy. SIRT1 overexpression attenuated DDR and mitochondrial dysfunction and downregulated the increase of hall makers senescence caused by Cd in osteoblasts. We found overexpression of osteoblastic SIRT1 protects against Cd-induced senescence, which is likely driven by ATM-mediated DDR and SOD2ace-mediated mitochondrial dysfunction. Our study demonstrates the mechanism of SIRT1 in mediating bone homeostasis via senescence. Further mechanistic studies using specific SIRT1 mutations elucidating how SIRT1 modulates bone cell senescence, will provide new therapeutic strategies for human osteoporosis.

Exogenous melatonin ameliorates steroid-induced osteonecrosis of the femoral head by modulating ferroptosis through GDF15-mediated signaling

BACKGROUND

Ferroptosis is an iron-related form of programmed cell death. Accumulating evidence has identified the pathogenic role of ferroptosis in multiple orthopedic disorders. However, the relationship between ferroptosis and SONFH is still unclear. In addition, despite being a common disease in orthopedics, there is still no effective treatment for SONFH. Therefore, clarifying the pathogenic mechanism of SONFH and investigating pharmacologic inhibitors from approved clinical drugs for SONFH is an effective strategy for clinical translation. Melatonin (MT), an endocrine hormone that has become a popular dietary supplement because of its excellent antioxidation, was supplemented from an external source to treat glucocorticoid-induced damage in this study.

METHODS

Methylprednisolone, a commonly used glucocorticoid in the clinic, was selected to simulate glucocorticoid-induced injury in the current study. Ferroptosis was observed through the detection of ferroptosis-associated genes, lipid peroxidation and mitochondrial function. Bioinformatics analysis was performed to explore the mechanism of SONFH. In addition, a melatonin receptor antagonist and shGDF15 were applied to block the therapeutic effect of MT to further confirm the mechanism. Finally, cell experiments and the SONFH rat model were used to detect the therapeutic effects of MT.

RESULTS

MT alleviated bone loss in SONFH rats by maintaining BMSC activity through suppression of ferroptosis. The results are further verified by the melatonin MT2 receptor antagonist that can block the therapeutic effects of MT. In addition, bioinformatic analysis and subsequent experiments confirmed that growth differentiation factor 15 (GDF15), a stress response cytokine, was downregulated in the process of SONFH. On the contrary, MT treatment increased the expression of GDF15 in bone marrow mesenchymal stem cells. Lastly, rescue experiments performed with shGDF15 confirmed that GDF15 plays a key role in the therapeutic effects of melatonin.

CONCLUSIONS

We proposed that MT attenuated SONFH by inhibiting ferroptosis through the regulation of GDF15, and supplementation with exogenous MT might be a promising method for the treatment of SONFH.

Synthesis, biological activity and mechanism of action of novel allosecurinine derivatives as potential antitumor agents

Cancer with low survival rates is the second main cause of death among all diseases in the world and consequently, effective antineoplastic agents are urgently needed. Allosecurinine is a plant-derived indolicidine securinega alkaloid shown bioactivity. The object of this study is to investigate synthetic allosecurinine derivatives with considerable anticancer capacity against nine human cancer cell lines as well as mechanism of action. We synthesized twenty-three novel allosecurinine derivatives and evaluated their antitumor activity against nine cancer cell lines for 72 h by MTT and CCK8 assays. FCM was applied to analyze the apoptosis, mitochondrial membrane potential, DNA content, ROS production, CD11b expression. Western blot was selected to analyze the protein expression. Structure-activity relationships were established and potential anticancer lead BA-3 which induced differentiation of leukemia cells towards granulocytosis at low concentration and apoptosis at high concentration was identified. Mechanism studies showed that mitochondrial pathway mediated apoptosis within cancer cells with cell cycle blocking was induced by BA-3. In addition, western blot assays revealed that BA-3 induced expression of the proapoptotic factor Bax, p21 and reduced the levels of antiapoptotic protein such as Bcl-2, XIAP, YAP1, PARP, STAT3, p-STAT3, and c-Myc. Collectively, BA-3 was a lead compound for oncotherapy at least in part, through the STAT3 pathway. These results were an important step in further studies on allosecurinine-based antitumor agent development.