Lack of ZnT8 protects pancreatic islets from hypoxia- and cytokine induced cell death

Pancreatic β-cells depend on the well-balanced regulation of cytosolic zinc concentrations, providing sufficient zinc ions for the processing and storage of insulin, but avoiding toxic effects. The zinc transporter ZnT8, encoded by SLC30A8, is a key player regarding islet cell zinc homeostasis, and polymorphisms in this gene are associated with altered type 2 diabetes susceptibility in man. The objective of this study was to investigate the role of ZnT8 and zinc in situations of cellular stress as hypoxia or inflammation. Isolated islets of wild-type and global ZnT8-/- mice were exposed to hypoxia or cytokines and cell death was measured. To explore the role of changing intracellular Zn2+ concentrations, wild-type islets were exposed to different zinc concentrations using zinc chloride or the zinc chelator N,N,N′,N′-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN). Hypoxia or cytokine (TNFα, IFNγ, IL1β) treatment induced islet cell death, but to a lesser extent in islets from ZnT8-/- mice, which were shown to have a reduced zinc content. Similarly, chelation of zinc with TPEN reduced cell death in wild-type islets treated with hypoxia or cytokines, whereas increased zinc concentrations aggravated the effects of these stressors. This study demonstrates a reduced rate of cell death in islets from ZnT8-/- mice as compared to wild-type islets when exposed to two distinct cellular stressors, hypoxia or cytotoxic cytokines. This protection from cell death is, in part, mediated by a reduced zinc content in islet cells of ZnT8-/- mice. These findings may be relevant for altered diabetes burden in carriers of risk SLC30A8 alleles in man.

Pitfalls at Chemistry of Adenoviral Vector Vaccine against COVID-19 and how to Circumvent It.

ChAdOx1 nCoV-19 vaccine is an adenovirus vector vaccine that designed to provoke immunity against SARS-CoV-2.This vaccine contains several inactive ingredients, including sodium chloride, magnesium chloride hexahydrate, ethanol, sucrose, and Ethylenediaminetetraacetic acid (EDTA).EDTA is a very potent zinc chelator which is used commonly in protein interaction studies. Exposure to EDTA even in lower concentrations may cause extreme stripping of zinc from many proteins, in-cluding zinc-binding proteins that described as a component of the largest and most complex gene superfamily in metazoans and the most common class of transcription factors.the EDTA-induced thrombocytopenia is a risk phenomenon caused by EDTA-dependent anti-platelet auto-antibodies that identify antigens modified by EDTA.Another issue is the adenovirus in the vaccine. It can induce thrombocytopenia, a potentially serious complication of gene therapy protocols using this type of vector.PEGylation already induced significantly lower serum il-6 levels by 70% (14)We noted that the study by Katie et al studied immune response by a single dose of ChAdOx1 nCov-19 not included test of Il-6 (15)We conclude from previous studies that the PEGylating of adenoviral vectors can be promise tech-nology as safety profile as significantly reduced IL-6 and liver toxicity and how avoiding the pitfalls of chemistry and virology so the PEGylation since first time at 1999 introduced by O’Riordan,C.R et al (16) need more advancements

Pitfalls at Chemistry of Adenoviral Vector Vaccine against COVID-19 and how to Circumvent It.

ChAdOx1 nCoV-19 vaccine is an adenovirus vector vaccine that designed to provoke immunity against SARS-CoV-2. EDTA is a very potent zinc chelator which is used commonly in protein interaction studies. Exposure to EDTA even in lower concentrations may cause extreme stripping of zinc from many proteins, in-cluding zinc-binding proteins that described as a component of the largest and most complex gene superfamily in metazoans and the most common class of transcription factors. The zinc dissociation rates can vary greatly among these proteins. Another issue is the adenovirus in the vaccine. It can induce thrombocytopenia, a potentially serious complication of gene therapy protocols using this type of vector.PEGylation already induced significantly lower serum il-6 levels by 70% .We noted that the study by Katie et al studied immune response by a single dose of ChAdOx1 nCov-19 not included test of Il-6 (15)We conclude from previous studies that the PEGylating of adenoviral vectors can be promise tech-nology as safety profile as significantly reduced IL-6 and liver toxicity and how avoiding the pitfalls of chemistry and virology so the PEGylation since first time at 1999 introduced by O’Riordan,C.R et al (16) need more advancements

Calprotectin-mediated zinc chelation inhibits Pseudomonas aeruginosa protease activity in cystic fibrosis sputum

Pseudomonas aeruginosa induces pathways indicative of low zinc availability in the cystic fibrosis (CF) lung environment. To learn more about P. aeruginosa zinc access in CF, we grew P. aeruginosa strain PAO1 directly in expectorated CF sputum. The P. aeruginosa Zur transcriptional repressor controls the response to low intracellular zinc, and we used the NanoString methodology to monitor levels of Zur-regulated transcripts including those encoding a zincophore system, a zinc importer, and paralogs of zinc containing proteins that do not require zinc for activity. Zur-controlled transcripts were induced in sputum-grown P. aeruginosa compared to control cultures, but not if the sputum was amended with zinc. Amendment of sputum with ferrous iron did not reduce expression of Zur-regulated genes. A reporter fusion to a Zur-regulated promoter had variable activity in P. aeruginosa grown in sputum from different donors, and this variation inversely correlated with sputum zinc concentrations. Recombinant human calprotectin (CP), a divalent-metal binding protein released by neutrophils, was sufficient to induce a zinc-starvation response in P. aeruginosa grown in laboratory medium or zinc-amended CF sputum indicating that CP is functional in the sputum environment. Zinc metalloproteases comprise a large fraction of secreted zinc-binding P. aeruginosa proteins. Here we show that recombinant CP inhibited both LasB-mediated casein degradation and LasA-mediated lysis of Staphylococcus aureus, which was reversible with added zinc. These studies reveal the potential for CP-mediated zinc chelation to post-translationally inhibit zinc metalloprotease activity and thereby impact the protease-dependent physiology and/or virulence of P. aeruginosa in the CF lung environment. Importance The factors that contribute to worse outcomes in individuals with cystic fibrosis (CF) with chronic Pseudomonas aeruginosa infections are not well understood. Therefore, there is a need to understand environmental factors within the CF airway that contribute to P. aeruginosa colonization and infection. We demonstrate that growing bacteria in CF sputum induces a zinc-starvation response that inversely correlates with sputum zinc levels. Additionally, both calprotectin and a chemical zinc chelator inhibit the proteolytic activities of LasA and LasB proteases suggesting that extracellular zinc chelators can influence proteolytic activity and thus P. aeruginosa virulence and nutrient acquisition in vivo.

Zinc transporter ZIP7 is a novel determinant of ferroptosis

Ferroptosis is a newly described form of regulated cell death triggered by oxidative stresses and characterized by extensive lipid peroxidation and membrane damages. The name of ferroptosis indicates that the ferroptotic death process depends on iron, but not other metals, as one of its canonical features. Here, we reported that zinc is also essential for ferroptosis in breast and renal cancer cells. Zinc chelator suppressed ferroptosis, and zinc addition promoted ferroptosis, even during iron chelation. By interrogating zinc-related genes in a genome-wide RNAi screen of ferroptosis, we identified SLC39A7, encoding ZIP7 that controls zinc transport from endoplasmic reticulum (ER) to cytosol, as a novel genetic determinant of ferroptosis. Genetic and chemical inhibition of the ZIP7 protected cells against ferroptosis, and the ferroptosis protection upon ZIP7 knockdown can be abolished by zinc supplementation. We found that the genetic and chemical inhibition of ZIP7 triggered ER stresses, including the induction of the expression of HERPUD1 and ATF3. Importantly, the knockdown of HERPUD1 abolished the ferroptosis protection phenotypes of ZIP7 inhibition. Together, we have uncovered an unexpected role of ZIP7 in ferroptosis by maintaining ER homeostasis. These findings may have therapeutic implications for human diseases involving ferroptosis and zinc dysregulations.

Recent advances and current perspectives in treatment of Alzheimer’s disease

Dementia is a disorder which is associated with disruption of cerebral neurons, resulting in its characteristic symptomatology. Acetylcholine neurotransmitter is found to be significant for processing memory and learning. However it is diminished in both concentration and function in patients with Alzheimer disease. Nootropics are the drugs which is used to improve memory and learning by acting as AChEI (Acetyl cholineesterase inhibitors). Cognitive enhancers include drugs interacting with receptors (e.g. NMDA receptor antagonist: memantine), Enzymes (e.g. AChE inhibitors: tacrine, donepezil, galantamine), Antioxidants (e.g. resveratrol, curcumin, and acetyl-L-carnitine), Metal chelators (e.g. calcium and zinc chelator: DP-b99), Vaccines, Monoclonal antibodies (e.g. A beta-Amyloid: solanezumab under Phase III clinical trial). Apart from the pharmacological approaches, supplementation of a healthy diet and healthy physical & mental lifestyle impact cognitive research in the future. There is no remedy for AD. Contemporary treatments just relive the behaviourial symptoms.Treatment centers around making a superior personal satisfaction for the individuals with Alzheimer infection. As of late, undifferentiated cell innovation (stem cell technology), and Nanotechnology has given new bits of knowledge into the treatment of Alzheimer's disease. In this review, we talk about current indicative medicines and future difficulties for new potential illness altering treatments.

Zinc supports transcription and improves meiotic competence of growing bovine oocytes

In the last years, many studies focused on the understanding of the possible role of zinc in the control of mammalian oogenesis, mainly on oocyte maturation and fertilization. However, little is known about the role of zinc at earlier stages, when the growing oocyte is actively transcribing molecules that will regulate and sustain subsequent stages of oocyte and embryonic development. In this study, we used the bovine model to gain insights into the possible involvement of zinc in oocyte development. We first mined the EmbryoGENE transcriptomic dataset, which revealed that several zinc transporters and methallothionein are impacted by physiological conditions throughout the final phase of oocyte growth and differentiation. We then observed that zinc supplementation during in vitro culture of growing oocytes is beneficial to the acquisition of meiotic competence when subsequently subjected to standard in vitro maturation. Furthermore, we tested the hypothesis that zinc supplementation might support transcription in growing oocytes. This hypothesis was indirectly confirmed by the experimental evidence that the content of labile zinc in the oocyte decreases when a major drop in transcription occurs in vivo. Accordingly, we observed that zinc sequestration with a zinc chelator rapidly reduced global transcription in growing oocytes, which was reversed by zinc supplementation in the culture medium. Finally, zinc supplementation impacted the chromatin state by reducing the level of global DNA methylation, which is consistent with the increased transcription. In conclusion, our study suggests that altering zinc availability by culture-medium supplementation supports global transcription, ultimately enhancing meiotic competence.

Influence of oocyte selection, activation with a zinc chelator and inhibition of histone deacetylases on cloned porcine embryo and chemically activated oocytes development

SummaryThe aim of this study was to evaluate the effects of alternative protocols to improve oocyte selection, embryo activation and genomic reprogramming on in vitro development of porcine embryos cloned by somatic cell nuclear transfer (SCNT). In Experiment 1, in vitro-matured oocytes were selected by exposure to a hyperosmotic sucrose solution prior to micromanipulation. In Experiment 2, an alternative chemical activation protocol using a zinc chelator as an adjuvant (ionomycin + N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) + N-6-dimethylaminopurine (6-DMAP)) was compared with a standard protocol (ionomycin + 6-DMAP) for the activation of porcine oocytes or SCNT embryos. In Experiment 3, presumptive cloned zygotes were incubated after chemical activation in a histone deacetylase inhibitor (Scriptaid) for 15 h, with the evaluation of embryo yield and total cell number in day 7 blastocysts. In Experiment 1, cleavage rates tended to be higher in sucrose-treated oocytes than controls (123/199, 61.8% vs. 119/222, 53.6%, respectively); however, blastocyst rates were similar between groups. In Experiment 2, cleavage rates were higher in zygotes treated with TPEN than controls but no difference in blastocyst rates between groups occurred. For Experiment 3, the exposure to Scriptaid did not improve embryo development after cloning. Nevertheless, the total number of cells was higher in cloned zygotes treated with Scriptaid than SCNT controls. In conclusion, oocyte selection by sucrose as well as treatments with zinc chelator and an inhibitor of histone deacetylases did not significantly improve blastocyst yield in cloned and parthenotes. However, the histone deacetylases inhibitor produced a significant improvement in the blastocyst quality.