ZIP1 and zinc inhibits fluoride-induced apoptosis in MC3T3-E1 cells

Optimal submicron roughness for balancing degradation behavior, immune modulation, and microbial adhesion on zinc-based barrier membranes

Metallic zinc (Zn) has been demonstrated to be a promising alternative to barrier membrane materials for guided bone regeneration. Surface roughness significantly affects the properties of degradable Zn-based metals, especially within the Janus micro-environments of tissue regeneration. However, the effects of optimal surface roughness on Zn remain unknown. In this study, pure Zn surfaces were fabricated with three roughness scales: nano (Sa < 0.1 μm), submicron (Sa: 0.5-1.0 μm), and micron (Sa > 1.0 μm). Submicron-scale pure Zn exhibited a moderate degradation rate in simulated body fluids, and no deep corrosion pits appeared on the surface. By contrast, the degradation rate of nano-surface pure Zn decreased significantly, while localized corrosion tended to appear on micron surfaces. In addition, the degradation rate of Zn with different roughness was overall accelerated in artificial saliva, accompanied by varying degradation morphologies. Co-culturing with submicron samples inhibited macrophage polarization to the M1 phenotype. Nano-scale surfaces promoted macrophage polarization towards the M1 phenotype and exhibited significantly reduced antibacterial rates compared to rougher surfaces. These findings demonstrate that submicron-scale pure Zn could be an optimal choice for barrier membrane surfaces.

The Role of SIRT1-BDNF Signaling Pathway in Fluoride-Induced Toxicity for Glial BV-2 Cells

Chronic fluorosis is often accompanied by neurological symptoms, leading to attention, memory and learning ability decline and causing tension, anxiety, depression, and other mental symptoms. In the present study, we analyzed the molecular mechanisms of SIRT1-BDNF regulation of PI3K-AKT, MAPK, and FOXO1A in F-treated BV2 cells. The cytotoxic effect of sodium fluoride (NaF) on BV2 cells was assessed using Cell Counting Kit-8 (CCK-8), crystal violet, and 5-ethynyl-2'-deoxyuridine (EdU) staining. Cell cycle progression and apoptosis were evaluated through flow cytometry and western blotting. Reactive oxygen species (ROS) levels, oxidative stress, and inflammatory markers were measured by ROS staining, microplate reader assays, and western blotting. The role of SIRT1 in fluoride-induced toxicity for glial cells was determined using the SIRT1 activator SRT1720. The experiments demonstrated that NaF was toxic to BV2 cells, inhibited their proliferative ability, halted their cell cycle progression, triggered cellular apoptosis, promoted cellular oxidative stress (detected by ROS, SOD, MDA, GSH-Px, T-AOC) and associated protein NQO-1 and HO-1, and elevated inflammatory mediator associated protein IL-1and IL-6 expression). The fluoride-exposed groups had reduced SIRT1, BDNF, TrkB, PI3K, AKT, and MAPK protein expression levels, and increased FOXO1A protein expression. SRT1720 mitigated the harmful effects of NaF, stimulated cell proliferation and cell cycle progression, decreased apoptosis, reduced oxidative stress and inflammatory factors, elevated SIRT1, BDNF, TrkB, PI3K, AKT, and MAPK protein levels, and suppressed FOXO1A protein expression. The results indicate that NaF potentially harms glial cells by suppressing SIRT1 activation, and SIRT1 significantly mitigated the damage. Furthermore, the SIRT1 signaling pathway might regulate the nerve damage caused by fluoride poisoning and may be a protective factor in treating fluoride-induced brain injury.

Effect of zinc intake on association between fluoride exposure and abnormal sex steroid hormones among US pubertal males: NHANES, 2013-2016

Excessive fluoride exposure can disturb the balance of sex hormones. Zinc is essential for sex hormone synthesis and spermatogenesis. But it is not clear how zinc affects the relationship of fluoride exposure with abnormal sex steroid hormones. Here, a total of 1008 pubertal males from the National Health and Nutrition Examination Survey (NHANES) in two cycles (2013-2014, 2015-2016) were enrolled. The concentrations of water fluoride and plasma fluoride and the levels of serum testosterone, estradiol, and sex hormone binding globulin (SHBG) were measured. Two 24-h dietary recall interviews were conducted to assess the dietary zinc intake. The relationships of fluoride exposure and zinc intake with sex hormones were examined using linear regression and logistic regression models, while the generalized additive model was used to evaluate their non-linear relationship. Our findings revealed that for every two-fold increase in plasma fluoride concentration, testosterone levels decreased by 7.27% (95% CI - 11.49%, - 2.86%) and estradiol levels decreased by 8.73% (95% CI - 13.61%, - 3.57%). There was also significant non-linear association observed between zinc intake and SHBG levels. Being in the first tertile of plasma fluoride had a 60% lower risk of high SHBG (OR = 0.40, 95% CI 0.18, 0.89) compared with being in the second tertile. When compared to the first tertile, being in the second tertile of zinc intake was associated with a 63% (OR = 0.37, 95% CI 0.14, 0.98) lower risk of high SHBG. Furthermore, we observed an interactive effect between the plasma fluoride and zinc intake on estradiol and SHBG, as well as the risk of high SHBG (P-interaction < 0.10). These findings suggest that fluoride exposure and zinc intake can affect sex steroid hormone levels and the risk of high SHBG. Notably, zinc intake may alleviate the increased risk of high SHBG and the abnormal changes of estradiol and SHBG caused by higher fluoride exposure.

Premature ovarian insufficiency: a review on the role of oxidative stress and the application of antioxidants

Normal levels of reactive oxygen species (ROS) play an important role in regulating follicular growth, angiogenesis and sex hormone synthesis in ovarian tissue. When the balance between ROS and antioxidants is disrupted, however, it can cause serious consequences of oxidative stress (OS), and the quantity and quality of oocytes will decline. Therefore, this review discusses the interrelationship between OS and premature ovarian insufficiency (POI), the potential mechanisms and the methods by which antioxidants can improve POI through controlling the level of OS. We found that OS can mediate changes in genetic materials, signal pathways, transcription factors and ovarian microenvironment, resulting in abnormal apoptosis of ovarian granulosa cells (GCs) and abnormal meiosis as well as decreased mitochondrial Deoxyribonucleic Acid(mtDNA) and other changes, thus accelerating the process of ovarian aging. However, antioxidants, mesenchymal stem cells (MSCs), biological enzymes and other antioxidants can delay the disease process of POI by reducing the ROS level in vivo.

Upregulated Solute Carrier SLC39A1 Promotes Gastric Cancer Proliferation and Indicates Unfavorable Prognosis

Backgrounds

Solute carrier 39A1 (SLC39A1) is an indirect zinc transporter which showed diverse tumor-related functions in different malignancies. Here, we aimed to investigate its expression and role in gastric adenocarcinoma.

Methods

A retrospective gastric adenocarcinoma cohort (n = 154) was collected from our hospital to test their tissue expression of SLC39A1 through immunohistochemical staining method. After SLC39A1 overexpression or knockdown, proliferation and invasion assays were conducted for proliferation and invasion estimation, respectively. Xenograft in nude mice was used as the in vivo strategy to validate in vitro findings.

Results

Compared with adjacent stomach tissues, gastric adenocarcinoma tissues showed significantly higher SLC39A1 on both mRNA and protein levels. Higher SLC39A1 was observed in patients with larger tumor size (P=0.003) and advanced tumor stages (P < 0.001). Univariate (P=0.001) and multivariate analyses (P=0.035) confirmed the independent prognostic significance of SLC39A1 on gastric adenocarcinoma outcomes. The median survival time was 22.0 months in patients with high-SLC39A1 expression, while up to 57.0 months in those with low-SLC39A1 (P=0.001). In vitro and in vivo assays demonstrated that overexpressing SLC39A1 could promote gastric cancer growth and invasion, while silencing SLC39A1 led to opposite effects.

Conclusions

Aberrant high-SLC39A1 expression can serve as an independent unfavorable prognostic factor for gastric adenocarcinoma. High SLC39A1 is critical for a more aggressive tumor phenotype by promoting cell proliferation and invasion. Therefore, targeting SLC39A1 may provide novel therapeutic insights.

Zinc Protects against Heat Stress-Induced Apoptosis via the Inhibition of Endoplasmic Reticulum Stress in TM3 Leydig Cells

Heat stress (HS)-induced apoptosis in Leydig cells is mediated by various molecular mechanisms, including endoplasmic reticulum (ER) stress. Zinc, an inorganic mineral element, exhibits several cytoprotective properties, but its potential protective action against Leydig cell apoptosis and the related molecular mechanisms has not been fully elucidated. In this study, we evaluated the effects of zinc sulfate, a predominant chemical form of zinc, exerted on cell viability, apoptosis, and testosterone production in HS-treated TM3 Leydig cells and investigated the underlying signaling pathways. HS treatment inhibited cell viability and induced apoptosis, which was accompanied by the induction of the activity of caspase 3, an executioner of apoptosis, involved in the expression of pro-apoptotic protein B cell lymphoma 2-associated X protein (Bax), and in the reduction of the expression of anti-apoptotic protein B cell lymphoma 2 (Bcl-2), thereby activating ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP)). However, zinc sulfate led to the attenuation of deleterious effects, including increases in apoptosis, caspase-3 activity, Bax, GRP78, and CHOP expression, and decreases in cell viability and Bcl-2 protein expression in cells treated with HS or thapsigargin (an ER stress activator). Furthermore, 4-phenylbutyric acid (an ER stress inhibitor) treatment markedly alleviated the HS-induced adverse effects in cells exposed to HS, which was similar to zinc sulfate. Additionally, zinc sulfate supplementation in the culture medium effectively restored the HS-induced decrease in testosterone levels in HS-treated cells. In summary, these findings indicate that HS triggers apoptosis in TM3 Leydig cells via the ER stress pathway and that zinc confers protection against these detrimental effects. This study provides new insights into the benefits of using zinc against HS-induced apoptosis and cell injury.

Insight into the roles of melatonin in bone tissue and bone‑related diseases (Review)

Bone‑related diseases comprise a large group of common diseases, including fractures, osteoporosis and osteoarthritis (OA), which affect a large number of individuals, particularly the elderly. The progressive destruction and loss of alveolar bone caused by periodontitis is a specific type of bone loss, which has a high incidence and markedly reduces the quality of life of patients. With the existing methods of prevention and treatment, the incidence and mortality of bone‑related diseases are still gradually increasing, creating a significant financial burden to societies worldwide. To prevent the occurrence of bone‑related diseases, delay their progression or reverse the injuries they cause, new alternative or complementary treatments need to be developed. Melatonin exerts numerous physiological effects, including inducing anti‑inflammatory and antioxidative functions, resetting circadian rhythms and promoting wound healing and tissue regeneration. Melatonin also participates in the health management of bone and cartilage. In the present review, the potential roles of melatonin in the pathogenesis and progression of bone injury, osteoporosis, OA and periodontitis are summarized. Furthermore, the high efficiency and diversity of the physiological regulatory effects of melatonin are highlighted and the potential benefits of the use of melatonin for the clinical prevention and treatment of bone‑related diseases are discussed.

Compound ammonium glycyrrhizin protects hepatocytes from injury induced by lipopolysaccharide/florfenicol through oxidative stress and a MAPK pathway

Compound ammonium glycyrrhizin (CAG) protects hepatocytes from injury induced by lipopolysaccharide (LPS)/florfenicol (FFC) through a mitochondrial pathway. On this basis, the research was aimed to investigate whether CAG protects hepatocytes from injury induced by LPS/FFC through oxidative stress and the MAPK pathway. For liver injury induced by LPS/FFC, not only CAG can protect hepatocytes and prevent membrane permeability from being increased, but also the activities of ALT and AST were decreased significantly by CAG. Flow cytometry analysis indicated that the apoptosis rate (35.65 ± 2.48%) of LPS/FFC group was significantly higher than that of the control group (8.60 ± 0.32%). CAG (concentration of 0.01 μg/mL, 0.1 μg/mL, 1 μg/mL) significantly decreased the apoptosis rate (23.69 ± 0.54%, 14.92 ± 2.45% and 9.47 ± 1.28%) for the liver injury induced by LPS/FFC. The activities of SOD and GSH were increased with the increased concentration of CAG, and the activity of MDA was decreased with the increased concentration of CAG. All the mRNA and proteins expression levels were increased by LPS/FFC-induced liver injury which associated with the MAPK pathway, and those of the CAG group were decreased with the increased concentration of CAG. And the change of caspase-3 activity was consistent with that of proteins and mRNA. It is suggested that LPS/FFC can induce liver injury through apoptosis and the CAG can protect hepatocytes from injury through the MAPK pathway and oxidative stress.

Metal ions influx is a double edged sword for the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is a common form of dementia in aged people, which is defined by two pathological characteristics: β-amyloid protein (Aβ) deposition and tau hyperphosphorylation. Although the mechanisms of AD development are still being debated, a series of evidence supports the idea that metals, such as copper, iron, zinc, magnesium and aluminium, are involved in the pathogenesis of the disease. In particular, the processes of Aβ deposition in senile plaques (SP) and the inclusion of phosphorylated tau in neurofibrillary tangles (NFTs) are markedly influenced by alterations in the homeostasis of the aforementioned metal ions. Moreover, the mechanisms of oxidative stress, synaptic plasticity, neurotoxicity, autophagy and apoptosis mediate the effects of metal ions-induced the aggregation state of Aβ and phosphorylated tau on AD development. More importantly, imbalance of these mechanisms finally caused cognitive decline in different experiment models. Collectively, reconstructing the signaling network that regulates AD progression by metal ions may provide novel insights for developing chelators specific for metal ions to combat AD.