Zinc Ion Homeostasis Research Articles

Zinc and copper effect mechanical cell adhesion properties of the amyloid precursor protein.

The amyloid precursor protein (APP) can be modulated by the binding of copper and zinc ions. Both ions bind with low nanomolar affinities to both subdomains (E1and E2) in the extracellular domain of APP. However, the impact of ion binding on structural and mechanical trans-dimerization properties is yet unclear. Using a bead aggregation assay (BAA), we found that zinc ions increase the dimerization of both subdomains, while copper promotes only dimerization of the E1 domain. In line with this, scanning force spectroscopy (SFS) analysis revealed an increase in APP adhesion force up to three-fold for copper and zinc. Interestingly, however, copper did not alter the separation length of APP dimers, whereas high zinc concentrations caused alterations in the structural features and a decrease of separation length. Together, our data provide clear differences in copper and zinc mediated APP trans-dimerization and indicate that zinc binding might favor a less flexible APP structure. This fact is of significant interest since changes in zinc and copper ion homeostasis are observed in Alzheimer's disease (AD) and were reported to affect synaptic plasticity. Thus, modulation of APP trans-dimerization by copper and zinc could contribute to early synaptic instability in AD.

A dual-pathway pyroptosis inducer based on Au–Cu2-xSe@ZIF-8 enhances tumor immunotherapy by disrupting the zinc ion homeostasis

The regulation of intracellular ionic homeostasis to trigger antigen-specific immune responses has attracted extensive interest in tumor therapy. In this study, we developed a dual-pathway nanoreactor, Au-Cu2-xSe@ZIF-8@P18 NPs (ACS-Z-P NPs), which targets danger-associated molecular patterns (DAMPs) and releases Zn2+ and reactive oxygen species (ROS) within the tumor microenvironment (TME). Zn2+ released from the metal–organic frameworks (MOFs) was deposited in the cytoplasm, leading to aberrant transcription levels of intracellular zinc-regulated proteins and DNA damage, thereby inducing pyroptosis and immunogenic cell death (ICD) dependent on caspase1/gasdermin D (GSDMD) pathway. Furthermore, upon laser irradiation, ACS-Z-P NPs could break through the limitations of inherent defects of immunosuppression in TME, enhance ROS generation through a Fenton-like reaction cascade, which subsequently triggered the activation of inflammatory vesicles and the release of damage-associated molecular patterns (DAMPs). This cascade effect led to the amplification of pyroptosis and immunogenic cell death (ICD), thereby remodeling the immunosuppressed TME. Consequently, this process improved dendritic cell (DC) antigen presentation and augmented anti-tumor T-cell responses, effectively initiating antigen-specific immune responses and further enhancing pyroptosis and ICD. This study explores the therapeutic properties of these mechanisms in detail. Statement of significanceThe synthesized Au-Cu2-xSe@ZIF-8@P18 nanoparticles (ACS-Z-Ps) can effectively enhance the bodyʼs immune response by regulating zinc ion levels within cells. This regulation leads to abnormal levels of zinc-regulated protein transcription and DNA damage, which induces cellular pyroptosis. As a result, antigen presentation to dendritic cells (DCs) is improved, and anti-tumor T-cell responses are enhanced.The ACS-Z-P NPs overcome the limitations of ROS deficiency and immunosuppression in the tumor microenvironment by using H2O2 in the tumor microenvironment through a Fenton-like reaction. This leads to an increased production of ROS and O2, remodeling of the immunosuppressed tumor microenvironment, and enhanced induction of cell pyroptosis and immunogenic cell death.ACS-Z-P NPs targeted B16 cells using the photosensitizer P18 in combination with PDT treatment. This approach significantly inhibited the proliferation of B16 cells and effectively inhibited tumor growth.

Construction of ferroptosis-related prediction model for pathogenesis, diagnosis and treatment of ruptured abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a dangerous cardiovascular disease, which often brings great psychological burden and economic pressure to patients. If AAA rupture occurs, it is a serious threat to patients' lives. Therefore, it is of clinical value to actively explore the pathogenesis of ruptured AAA and prevent its occurrence. Ferroptosis is a new type of cell death dependent on lipid peroxidation, which plays an important role in many cardiovascular diseases. In this study, we used online data and analysis of ferroptosis-related genes to uncover the formation of ruptured AAA and potential therapeutic targets. We obtained ferroptosis-related differentially expressed genes (Fe-DEGs) from GSE98278 dataset and 259 known ferroptosis-related genes from FerrDb website. Enrichment analysis of differentially expressed genes (DEGs) was performed by gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG). Receiver Operating characteristic (ROC) curve was employed to evaluate the diagnostic abilities of Fe-DEGs. Transcription factors and miRNAs of Fe-DEGs were identified through PASTAA and miRDB, miRWalk, TargetScan respectively. Single-sample gene set enrichment analysis (ssGSEA) was used to observe immune infiltration between the stable group and the rupture group. DGIdb database was performed to find potential targeted drugs of DEGs. GO and KEGG enrichment analysis found that DEGs mainly enriched in "cellular divalent inorganic cation homeostasis," "cellular zinc ion homeostasis," "divalent inorganic cation homeostasis," "Mineral absorption," "Cytokine - cytokine receptor interaction," "Coronavirus disease - COVID-19." Two up-regulated Fe-DEGs MT1G and DDIT4 were found to further analysis. Both single and combined applications of MT1G and DDIT4 showed good diagnostic efficacy (AUC = 0.8254, 0.8548, 0.8577, respectively). Transcription factors STAT1 and PU1 of MT1G and ARNT and MAX of DDIT4 were identified. Meanwhile, has_miR-548p-MT1G pairs, has_miR-53-3p/has_miR-181b-5p/ has_miR-664a-3p-DDIT4 pairs were found. B cells, NK cells, Th2 cells were high expression in the rupture group compared with the stable group, while DCs, Th1 cells were low expression in the rupture group. Targeted drugs against immunity, GEMCITABINE and INDOMETHACIN were discovered. We preliminarily explored the clinical significance of Fe-DEGs MT1G and DDIT4 in the diagnosis of ruptured AAA, and proposed possible upstream regulatory transcription factors and miRNAs. In addition, we also analyzed the immune infiltration of stable and rupture groups, and found possible targeted drugs for immunotherapy.

Long-term exposure to cadmium disrupts neurodevelopment in mature cerebral organoids

Cadmium (Cd) is a pervasive environmental pollutant. Increasing evidence suggests that Cd exposure during pregnancy can induce adverse neurodevelopmental outcomes. However, due to the limitations of neural cell and animal models, it is challenging to study the developmental neurotoxicity and underlying toxicity mechanism of long-term exposure to environmental pollutants during human brain development. In this study, chronic Cd exposure was performed in human mature cerebral organoids for 49 or 77 days. Our study found that prolonged exposure to Cd resulted in the inhibition of cerebral organoid growth and the disruption of neural differentiation and cortical layer organization. These potential consequences of chronic Cd exposure may include impaired GFAP expression, a reduction in SOX2+ neuronal progenitor cells, an increase in TUJ1+ immature neurons, as well as an initial increase and a subsequent decrease in both TBR2+ intermediate progenitors and CTIP2+ deep layer cortical neurons. Transcriptomic analyses revealed that long-term exposure to Cd disrupted zinc and copper ion homeostasis through excessive synthesis of metallothionein and disturbed synaptogenesis, as evidenced by inhibited postsynaptic protein. Our study employed mature cerebral organoids to evaluate the developmental neurotoxicity induced by long-term Cd exposure.

Urolithin A conjugation with NSAIDs inhibits its glucuronidation and maintains improvement of Caco-2 monolayers' barrier function

Urolithin A (UA) is an ellagitannin-derived postbiotic metabolite which emerged as a promising health-boosting agent, promoting mitophagy, improving skeletal muscle function, and suppressing the inflammatory response. However, phase II intestinal metabolism severely limits its biopotency, leading to the formation of nonactive glucuronides. To address this constraint, a set of new UA derivatives (UADs), conjugated with nonsteroidal anti-inflammatory drugs (NSAIDs), was synthesized. The bioavailability and inhibitory activity of UADs against UA-glucuronidation were evaluated using differentiated Caco-2 cell monolayers. Parallelly, after the administration of tested substances, the transepithelial electrical resistance (TEER) of the cell monolayers was continuously monitored using the CellZscope device. Though investigated UADs did not penetrate Caco-2 monolayers, all of them significantly suppressed the glucuronidation rate of UA, while conjugates with diclofenac increased the concentration of free molecule on the basolateral side. Moreover, esters of UA with diclofenac (DicloUA) and aspirin (AspUA) positively influenced cell membrane integrity. Western blot analysis revealed that some UADs, including DicloUA, increased the expression of pore-sealing tight junction proteins and decreased the level of pore-forming claudin-2, which may contribute to their beneficial activity towards the barrier function. To provide comprehensive insight into the mechanism of action of DicloUA, Caco-2 cells were subjected to transcriptomic analysis. Next-generation sequencing (NGS) uncovered substantial changes in the expression of genes involved, for instance, in multivesicular body organization and zinc ion homeostasis. The results presented in this study offer new perspectives on the beneficial effects of modifying UA's structure on its intestinal metabolism and bioactivity in vitro.

SLC35E1 promotes keratinocyte proliferation in psoriasis by regulating zinc homeostasis

Keratinocyte hyperproliferation is a key pathogenic factor in psoriasis. However, the mechanisms that regulate keratinocyte hyperproliferation in this condition remain unclear. Here, we found that SLC35E1 was highly expressed in keratinocytes of patients with psoriasis and that Slc35e1−/− mice displayed a less severe imiquimod (IMQ)-induced psoriasis-like phenotype than their wild-type siblings. In addition, SLC35E1 deficiency inhibited keratinocyte proliferation in both mice and cultured cells. On a molecular level, SLC35E1 was found to regulate zinc ion concentrations and subcellular localization, while zinc ion chelation reversed the IMQ-induced psoriatic phenotype in Slc35e1−/− mice. Meanwhile, epidermal zinc ion levels were decreased in patients with psoriasis and zinc ion supplementation alleviated the psoriatic phenotype in an IMQ-induced mouse model of psoriasis. Our results indicated that SLC35E1 can promote keratinocyte proliferation by regulating zinc ion homeostasis and zinc ion supplementation has potential as a therapy for psoriasis.

Cuproptosis-Related Genes CDK1 and COA6 Involved in the Prognosis Prediction of Liver Hepatocellular Carcinoma.

Liver hepatocellular carcinoma (LIHC) is the most frequently seen type of primary liver cancer. Cuproptosis is a novel form of cell death highly associated with mitochondrial metabolism. However, the clinical impact and pertinent mechanism of cuproptosis genes in LIHC remain largely unknown. From public databases, we systematically assessed common genes from LIHC differentially expressed genes (DEGs) and cuproptosis-related genes using bioinformatics analysis. These common genes were then analyzed by enrichment analysis, mutation analysis, risk score model, and others to find candidate hub genes related to LIHC and cuproptosis. Next, hub genes were determined by expression, clinical factors, immunoassay, and prognostic nomogram. Based on 129 cuproptosis-related genes and 3492 LIHC DEGs, we totally identified 21 downregulated and 18 upregulated common genes, and they were enriched in pathways, such as zinc ion homeostasis and oxidative phosphorylation. In the mutation analysis, missense mutation was the most common type in LIHC patients, and the common gene F5 had the highest mutation frequency. After LASSO-Cox regression analysis and prognostic analysis, CDK1, ABCB6, LCAT, and COA6 were identified as prognostic signature genes. Among them, ABCB6 and LCAT were lowly expressed in tumors, and CDK1 and COA6 were highly expressed in tumors. In addition, ABCB6 and LCAT were negatively correlated with 6 kinds of immune cells, while CDK1 and COA6 were positively correlated with them. CDK1 and COA6 were identified as hub genes related to LIHC by Cox regression analysis and prognostic nomogram. CDK1 and COA6 are two oncogenes in LIHC, which are involved in the molecular mechanism of cuproptosis and LIHC. Besides, CDK1 and COA6 can positively regulate the expressions of immune cells in LIHC. In clinical practice, they can be used as immunotherapeutic targets and prognostic predictors in LIHC, which sheds new light on the scientific fields of cuproptosis and LIHC.

Trehalose–Carnosine Prevents the Effects of Spinal Cord Injury Through Regulating Acute Inflammation and Zinc(II) Ion Homeostasis

Spinal cord injury (SCI) leads to long-term and permanent motor dysfunctions, and nervous system abnormalities. Injury to the spinal cord triggers a signaling cascade that results in activation of the inflammatory cascade, apoptosis, and Zn(II) ion homeostasis. Trehalose (Tre), a nonreducing disaccharide, and l-carnosine (Car), (β-alanyl-l-histidine), one of the endogenous histidine dipeptides have been recognized to suppress early inflammatory effects, oxidative stress and to possess neuroprotective effects. We report on the effects of the conjugation of Tre with Car (Tre–car) in reducing inflammation in in vitro and in vivo models. The in vitro study was performed using rat pheochromocytoma cells (PC12 cell line). After 24 h, Tre–car, Car, Tre, and Tre + Car mixture treatments, cells were collected and used to investigate Zn2+ homeostasis. The in vivo model of SCI was induced by extradural compression of the spinal cord at the T6–T8 levels. After treatments with Tre, Car and Tre–Car conjugate 1 and 6 h after SCI, spinal cord tissue was collected for analysis. In vitro results demonstrated the ionophore effect and chelating features of l-carnosine and its conjugate. In vivo, the Tre–car conjugate treatment counteracted the activation of the early inflammatory cascade, oxidative stress and apoptosis after SCI. The Tre–car conjugate stimulated neurotrophic factors release, and influenced Zn2+ homeostasis. We demonstrated that Tre–car, Tre and Car treatments improved tissue recovery after SCI. Tre–car decreased proinflammatory, oxidative stress mediators release, upregulated neurotrophic factors and restored Zn2+ homeostasis, suggesting that Tre–car may represent a promising therapeutic agent for counteracting the consequences of SCI.

Renal injury induced by cadmium chloride and the protective effect of vitamin C in mice

To investigate the renal injury induced by cadmium chloride(CdCl_2) and the protective effect of vitamin C(VC) in mice. Forty healthy clean grade male Kunming mice were randomly divided into 4 groups: control group(double distilled water gavage and intraperitoneal injection), VC group(200 mg/kg VC gavage and double distilled water intraperitoneal injection), CdCl_2 group(double distilled water gavage and 2 mg/kg CdCl_2 intraperitoneal injection), VC+CdCl_(2 )group(200 mg/kg VC gavage and 2 mg/kg CdCl_2 intraperitoneal injection). Exposure for 30 days.24 hours after the last exposure, the eyeballs were taken out for blood, and the renal tissue was immediately taken out to calculate kidney coefficient and then separate renal cells. The levels of reactive oxygen species(ROS) were detected by DCFH-DA kit and flow cytometry. Blood urea nitrogen(BUN), serum creatinine(Scr)and β2 microglobulin(β2-MG), cystatin C(Cys C), superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), malondialdehyde(MDA), Caspase3 and Caspase9 kits were used to detect the corresponding indicators respectively. The contents of Cd~(2+) and Zn~(2+) in serum and kidney were detected by graphite furnace atomic absorption spectrometry. The levels of kidney coefficient and BUN, Scr, β2-MG were 1.36±0.10, (19.34±0.63)mmol/L, (61.30±2.04)mmol/L and(1.02±0.10)g/mL respectively in CdCl_(2 )group, which were higher than those in the control group and VC group(P<0.05). The levels of the above four indexes in VC+CdCl_(2 )group were 1.09±0.10, (9.65±0.50)mmol/L, (41.85±1.27)mmol/L and(0.61±0.01)g/mL respectively, which were lower than those in CdCl_2 group(P<0.05). CdCl_2 exposure resulted in unclear glomerular contour, swelling of renal tubules, interstitial hyperemia, and exfoliated epithelial cells in the lumen. VC pretreatment could improve the above changes. The levels of Cd~(2+) in serum and renal tissue of mice in CdCl_2 group were(4.36±0.07)μg/L, (18.6±1.95)μg/g respectively, which were higher than that of control group and VC group(P<0.05), in VC+CdCl_2 group, the level were(2.12±0.06)μg/L and(2.18±0.09)μg/g, they were lower than that of CdCl_2 group(P<0.05). The level of serum Zn~(2+ )in CdCl_2 group was(11.35±1.03)μg/L, that was lower than control group(P<0.05). The level of serum Zn~(2+) in VC+CdCl_2 group was(26.98±3.13)μg/L, which was higher than that of CdCl_2 group(P<0.05). The levels of ROS, MDA, Caspase3 and Caspase9 in kidney tissue of mice in CdCl_2 group were(1.86±0.13), (4.78±0.15)nmol/mg, 1.50±0.24 and 1.69±0.17 respectively, which were higher than those in control group(P<0.05). And the level of GSH-Px was(261.3±23.36)U/mg, it was lower than that in control group(P<0.05). Compared with the CdCl_2 group, the levels of ROS, MDA, Caspase3 and Caspase9 in VC+CdCl_2 group decreased, and the level of GSH-Px increased, the difference was statistically significant(P<0.05). CdCl_2 exposure can lead to oxidative stress, damage of glomerulus and renal tubules, imbalance of zinc ion homeostasis, and damage of renal function. VC pretreatment can reduce the damage caused by CdCl_2 to a certain extent.

Transcriptional Regulation and Protein Localization of Zip10, Zip13 and Zip14 Transporters of Freshwater Teleost Yellow Catfish Pelteobagrus fulvidraco Following Zn Exposure in a Heterologous HEK293T Model.

Zip family proteins are involved in the control of zinc (Zn) ion homeostasis. The present study cloned the promoters and investigated the transcription responses and protein subcellular localizations of three LIV-1 subfamily members (zip10, zip13, and zip14) from common freshwater teleost yellow catfish, Pelteobagrus fulvidraco, using in vitro cultured HEK293T model cells. The 2278 bp, 1917 bp, and 1989 bp sequences of zip10, zip13, and zip14 promoters, respectively, were subcloned into pGL3-Basic plasmid for promoter activity analysis. The pcDNA3.1 plasmid coding EGFP tagged pfZip10, pfZip13, and pfZip14 were generated for subsequent confocal microscope analysis. Several potential transcription factors’ binding sites were predicted within the promoters. In vitro promoter analysis in the HEK293T cells showed that high Zn administration significantly reduced the transcriptional activities of the zip10, zip13, and zip14 promoters. The −2017 bp/−2004 bp MRE in the zip10 promoter, the −360 bp/−345 bp MRE in the zip13 promoter, and the −1457 bp/−1442 bp MRE in the zip14 promoter were functional loci that were involved in the regulation of the three zips. The −606 bp/−594 bp KLF4 binding site in the zip13 promoter was a functional locus responsible for zinc-responsive regulation of zip13. The −1383 bp/−1375 bp STAT3 binding site in the zip14 promoter was a functional locus responsible for zinc-responsive regulation of zip14. Moreover, confocal microscope analysis indicated that zinc incubation significantly reduced the fluorescence intensity of pfZip10-EGFP and pfZip14-EGFP but had no significant influence on pfZip13-EGFP fluorescence intensity. Further investigation found that pfZip10 localizes on cell membranes, pfZip14 colocalized with both cell membranes and lysosome, and pfZip13 colocalized with intracellular ER and Golgi. Our research illustrated the transcription regulation of zip10, zip13, and zip14 from P. fulvidraco under zinc administration, which provided a reference value for the mechanisms involved in Zip-family-mediated control of zinc homeostasis in vertebrates.

Spermatozoan Metabolism as a Non-Traditional Model for the Study of Huntington's Disease.

Huntington’s Disease (HD) is a fatal autosomal dominant neurodegenerative disease manifested through motor dysfunction and cognitive deficits. Decreased fertility is also observed in HD animal models and HD male patients, due to altered spermatogenesis and sperm function, thus resulting in reduced fertilization potential. Although some pharmaceuticals are currently utilized to mitigate HD symptoms, an effective treatment that remedies the pathogenesis of the disease is yet to be approved by the FDA. Identification of genes and relevant diagnostic biomarkers and therapeutic target pathways including glycolysis and mitochondrial complex-I-dependent respiration may be advantageous for early diagnosis, management, and treatment of the disease. This review addresses the HD pathway in neuronal and sperm metabolism, including relevant gene and protein expression in both neurons and spermatozoa, indicated in the pathogenesis of HD. Furthermore, zinc-containing and zinc-interacting proteins regulate and/or are regulated by zinc ion homeostasis in both neurons and spermatozoa. Therefore, this review also aims to explore the comparative role of zinc in both neuronal and sperm function. Ongoing studies aim to characterize the products of genes implicated in HD pathogenesis that are expressed in both neurons and spermatozoa to facilitate studies of future treatment avenues in HD and HD-related male infertility. The emerging link between zinc homeostasis and the HD pathway could lead to new treatments and diagnostic methods linking genetic sperm defects with somatic comorbidities.

The MreA Metal-Binding Sites C40, H65, and C69 Play a Critical Role in the Metal Tolerance of Pseudomonas putida KT2440.

Metal-binding proteins occur in the cytosol of most eubacteria. The hypothetical metal responsive protein MreA (PP-2969 gene; NreA) seems responsible for zinc, chromium, cadmium accumulation, and metal ion homeostasis. However, there is a lack of definitive evidence regarding the specific metal-binding sites of MreA protein. The present study aimed to identify putative metal-binding regions for MreA. In silico analysis revealed that amino acids C40, H65, and C69 (CHC region) seem critical for metal-protein interactions. We created site-directed mutants (SDM's) of MreA for interacted amino acids to validate in silico results. The differential scanning fluorimetry (DSF) and atomic absorption spectroscopy (AAS) showed that SDM strains of MreA protein curtailed metal accumulation compared to the wild types indicating C40, H65, and C69 amino acids are critical for metal binding. Thus, we report potential implications for MreA-bioengineered strains ofPseudomonas putida KT2440 for metal ion homeostasis by alleviating metal toxicity in the biological environment.

S1354 Modification of the Tight Junctional Barrier in Human Duodenal Mucosal by Oral Zinc Administration in a Patient-Based Study: RNA-Seq and Western Immunoblot Analyses

Introduction: Mucosal barrier function is targeted in a wide variety of GI disease. Celiac disease, IBD, GI malignancies, sepsis and a wide variety of GI microbial infectious diseases all compromise the GI barrier. The tight junctional (TJ) complex is pivotal in this regard. The ability to safely modify the TJ complex and reduce its leakiness could be prophylactically and/or therapeutically useful. Methods: Patients 18-80 years of age presenting for endoscopic medical surveillance of gastroesophageal disorders but free of current small bowel disease were recruited for study. Patients were instructed to administer orally either a zinc-gluconate medication (12 patients) (26 mg elemental zinc) or a sodium gluconate placebo (11 patients), BID, for 14 days immediately prior to their EGD. During their EGD, standard duodenal bulb biopsies were taken for Western immunoblot analysis and for mRNA analysis. Biopsies were immediately flash frozen on dry ice in the procedures room and stored at -195oC for subsequent extraction. For protein studies, biopsies were homogenized in lysis buffer, sonicated and then analyzed by PAGE and Western immunoblot using a variety of antibodies to TJ proteins. Analysis of the biopsy transcriptome was performed by high-throughput RNA-seq. Results: Transcriptome analysis of over 20,000 genes revealed upregulation of many known zinc-regulated genes such as metallothioneins A, B, F, G, H, L, and M. The TJ barrier gene, occludin (OCLN), was also upregulated. Enrichment analysis using GSEA showed zinc upregulating several gene ontology (GO) biological processes as well as cellular components and pathways (Reactome). These included Zinc Ion Homeostasis (GO), Response to Zinc Ion (GO), Cell Junction Organization (Reactome), Cell-Cell Junction Assembly (GO), and Tight Junction (GO). Western immunoblot analyses showed statistically significant upregulation (two-tailed t-test) of the TJ proteins, claudin-2 and tricellulin, in mucosal biopsies of the zinc-treated group. Claudins -3 and -5 showed significant upregulations, and claudin-7, a significant down regulation, in a one-tailed t-test. Claudins -1, -4 and -18 showed no trend regarding a zinc-induced change. Conclusion: This is the first evidence of intended modification of TJ complexes in humans in situ. The results follow on a large body of published literature showing zinc-induced TJ changes and improved barrier function in a variety of human epithelial cell culture and animal models.

Progesterone and anandamide diminish the inhibitory effect of zinc on mature human sperm.

Zinc ion (Zn2+) homeostasis is very important for sperm capacitation and hyperactivation. Zn2+ is a specific inhibitor of the voltage-dependent proton channel (Hv1). Intracellular alkalisation of human spermatozoa is mainly dependent on opening of Hv1. Anandamide may affect spermatozoa through activation of Hv1. An increase in intracellular pH and progesterone (P4) activate cation channels of spermatozoa (CatSper). This study was designed to elucidate the interaction between ZnCl2, P4 and anandamide on human sperm function and intracellular calcium concentrations ([Ca2+]i). Human normal semen samples (n = 30) were diluted (20 × 106 spermatozoa mL-1) and divided into control and ethanol (0.01%)-, anandamide (1 nM)-, ZnCl2 (1 mM)-, P4 (10µM)-, anandamide+ZnCl2- and P4+ZnCl2-treated groups. Sperm kinematics, viability, acrosome status and [Ca2+]i were assessed. The percentage of viable and motile spermatozoa and sperm velocity was reduced in the ZnCl2-treated groups. Anandamide and P4 attenuated the inhibitory effects of ZnCl2 on sperm kinematics. Loss of the acrosome membrane was observed in all experimental groups. P4 and anandamide are present naturally in secretions of the female reproductive tract and modulate the inhibitory effects of ZnCl2 on sperm kinematics. This attenuation is probably due to a change in [Ca2+]i and prevention of Hv1 inactivation by P4 and anandamide respectively.

Sex differences, growth, reproduction and zinc ion homeostasis of zebrafish after chronic dietary l-selenomethionine exposure

Several mechanisms regarding the developmental and reproductive toxicity of l-selenomethionine (SeMet) in freshwater fish have been widely reported. However, limited information was available on endocrine-disrupting effects of SeMet. In this study, zebrafish larvae (day 24 post-fertilization) were exposed to environmentally-relevant levels of dietary SeMet (control, 1.11 ± 0.11, 3.59 ± 0.20, 10.80 ± 0.52, 29.19 ± 0.46, and 58.63 ± 0.70 μg Se/g d.w. diet) for 90 days until sexual maturity. For the first time, a gender difference in the effect of SeMet on body mass of zebrafish was observed. The lowest observed adverse effect level (LOAEL) in male was 10.80 ± 0.52 μg Se/g d.w., while it was 29.19 ± 0.46 μg Se/g d.w. in female. Chronic exposure to dietary SeMet reduced the percentage of early vitellogenic oocyte in female and the percentage of spermatid in male by inhibiting the growth hormone/insulin-like growth factors (GH/IGFs) and hypothalamus-pituitary-gonad (HPG) systems, which was characterized by significant decreases in the transcriptional levels of gh, igf1, era, and ar. Se content in the liver of male was significantly higher than that in female when dietary Se level reached 10.80 ± 0.52 μg Se/g d.w.. Furthermore, the zinc content in the livers and gonads of both female and male treated with 29.19 ± 0.46 and 58.63 ± 0.70 μg Se/g d.w. diets was significantly reduced. Reduction of zinc ion not only led to the significantly upregulated transcriptional levels of zip1 and znt2, but also downregulated transcriptional levels of znf219l and sp7. In summary, this study provides a new evidence that chronic exposure to high level of dietary SeMet (≥10.80 μg Se/g d.w.) could impair the development and reproduction of zebrafish with gender difference by interfering the GH/IGFs and HPG systems. Moreover, disruption of zinc ion homeostasis might exacerbate the toxicity of Se to zebrafish.

Whole-transcriptome sequencing (RNA-seq) analyses of the zebrafish liver cell line, ZFL, after acute exposure to Cu2+ ions.

All cells require Cu as a cofactor, but Cu2+ induces toxicity and oxidative damage. A strict system is thus needed to maintain Cu homeostasis. Using the ZFL zebrafish liver cell line as a model, we studied the cellular responses after exposure to Cu2+, using whole-transcriptome shotgun sequencing (RNA-seq) to screen nearly all transcriptomes in cell samples and identify changes in gene expression. ZFL cells were treated with 100, 200, or 400 μM CuCl2 and harvested after 4 and 24 h. RNA was then extracted and subjected to RNA-Seq and qPCR validation. Exposure to 400 μM CuCl2 for 4 h and 24 h led to the regulation of 5993 and 4235 genes, respectively. In a gene ontology enrichment analysis, Cu2+ exposure enriched the nitrogen compound metabolic process and antioxidant activity but did not significantly affect cellular copper, zinc, iron and calcium ion homeostasis. In a KEGG pathway enrichment analysis, anti-oxidative stress induced the glutathione metabolism pathway. Furthermore, Cu2+ also induced genes related to apoptosis and arrested the cell cycle in the G2 phase. This study was based on the full gene expression profile combined with pathway analysis details, providing a full cellular response picture for Cu.

The Isolation of Pyrroloformamide Congeners and Characterization of Their Biosynthetic Gene Cluster.

Dithiolopyrrolones are microbial natural products containing a disulfide or thiosulfonate bridge embedded in a unique bicyclic structure. By interfering with zinc ion homeostasis in living cells, they show strong antibacterial activity against a variety of bacterial pathogens, as well as potent cytotoxicity against human cancer cells. In the current study, two new dithiolopyrrolones, pyrroloformamide C (3) and pyrroloformamide D (4), were isolated from Streptomyces sp. CB02980, together with the known pyrroloformamides 1 and 2. The biosynthetic gene cluster for pyrroloformamides was identified from Streptomyces sp. CB02980, which shared high sequence similarity with those of dithiolopyrrolones, including holomycin and thiolutin. Gene replacement of pyfE, which encodes a nonribosomal peptide synthetase (NRPS), abolished the production of 1-4. Overexpression of pyfN, a type II thioesterase gene, increased the production of 1 and 2. Genome neighborhood network analysis of the characterized and orphan gene clusters of dithiolopyrrolones revealed a unified mechanism for their biosynthesis, involving an iterative-acting NRPS and a set of conserved tailoring enzymes for the bicyclic core formation.

Evaluation of Long-Term Toxicity of Oral Zinc Oxide Nanoparticles and Zinc Sulfate in Mice

The toxicological effects of zinc oxide nanoparticles (nano-ZnOs) are related to their dissolution and interference with zinc ion homeostasis. High-soluble zinc sources may produce more severe and acute toxicity; however, the evaluation of potential toxicity of long-term exposure to nano-ZnOs and high-soluble sources of zinc remains obscure. This study aimed at evaluating effects of nano-ZnOs and zinc sulfate on development, serum and hematological parameters, and mineral concentrations in selected tissues and intestinal microbiota in mice via gastrointestinal administration for 7weeks. Results indicated that 250mg/kg nano-ZnOs reduced the body weight from weeks 8 to 11, increased serum glutamic-pyruvic transaminase activity, and increased the zinc concentrations of the serum, liver, and kidney while did not affect the relative organ weight, intestinal microbiota, and other mineral concentrations (Fe, Cu, and Mn) in the kidney, liver, and thigh muscle. Oral administration with 250mg/kg zinc sulfate seemed to show more severe and acute toxicity since mice in zinc sulfate group exhibited reduced body weight from weeks 5 to 11, decreased relative pancreas weight, and increased serum glutamic-oxalacetic transaminase activity and intestinal enteric group.

The mucolipin-1 (TRPML1) ion channel, transmembrane-163 (TMEM163) protein, and lysosomal zinc handling.

Lysosomes are emerging as important players in cellular zinc ion (Zn2+) homeostasis. The series of work on Zn2+ accumulation in the neuronal lysosomes and the mounting evidence on the role of lysosomal Zn2+ in cell death during mammary gland involution set a biological precedent for the central role of the lysosomes in cellular Zn2+ handling. Such a role appears to involve cytoprotection on the one hand, and cell death on the other. The recent series of work began to identify the molecular determinants of the lysosomal Zn2+ handling. In addition to zinc transporters (ZnT) of the solute-carrier family type 30A (SLC30A), the lysosomal ion channel TRPML1 and the poorly understood novel transporter TMEM163 have been shown to play a role in the Zn2+ uptake by the lysosomes. In this review, we summarize the current knowledge on molecular determinants of the lysosomal Zn2+ handling, uptake, and release pathways, as well as discuss their possible roles in health and disease.

Zinc and autophagy

Autophagy refers to a catabolic process,in which the damaged organelles or biological macromolecules, such as protein aggregates, are degraded via lysosome. The completion of autophagy depends on a series of autophagy-related genes (Atgs) and many upstream regulatory molecules. Zinc is an essential trace element, and plays an important role in the process of autophagy as a component of enzymes and structural proteins like zinc transporters or zinc finger protein. The regulation of autophagy is closely associated with the zinc ion homeostasis. In addition, many studies suggest that the protective effects of zinc on cells are likely to be done by autophagy. This review aims to summarize the current research progress and discuss the reciprocal regulation mechanism between zinc and autophagy, which may provide insights into the intricate roles of autophagy in diseases and find novel strategies for treatment and prevention of human diseases.