B cell activation and proliferation increase intracellular zinc levels

Dietary Zinc Supplementation in Steers Modulates Labile Zinc Concentration and Zinc Transporter Gene Expression in Circulating Immune Cells

Zinc (Zn) is critical for immune function, and marginal Zn deficiency in calves can lead to suboptimal growth and increased disease susceptibility. However, in contrast to other trace minerals such as copper, tissue concentrations of Zn do not change readily in conditions of supplementation or marginal deficiency. Therefore, the evaluation of Zn status remains challenging. Zinc transporters are essential for maintaining intracellular Zn homeostasis, and their expression may indicate changes in Zn status in the animal. Here, we investigated the effects of dietary Zn supplementation on labile Zn concentration and Zn transporter gene expression in circulating immune cells isolated from feedlot steers. Eighteen Angus crossbred steers (261 ± 14 kg) were blocked by body weight and randomly assigned to two dietary treatments: a control diet (58 mg Zn/kg DM, no supplemental Zn) or control plus 150 mg Zn/kg DM (HiZn; 207 mg Zn/kg DM total). After 33 days, Zn supplementation increased labile Zn concentrations (as FluoZin-3 fluorescence) in monocytes, granulocytes, and CD4 T cells (P < 0.05) but had the opposite effect on CD8 and γδ T cells (P < 0.05). Zn transporter gene expression was analyzed on purified immune cell populations collected on days 27 or 28. ZIP11 and ZnT1 gene expression was lower (P < 0.05) in CD4 T cells from HiZn compared to controls. Expression of ZIP6 in CD8 T cells (P = 0.02) and ZnT7 in B cells (P = 0.01) was upregulated in HiZn, while ZnT9 tended (P = 0.06) to increase in B cells from HiZn. These results suggest dietary Zn concentration affects both circulating immune cell Zn concentrations and Zn transporter gene expression in healthy steers.

Zinc deficiency impairs the development of human regulatory B cells from purified B cells

Zinc is a vital trace element, important for many different immune processes and adequate functionality. B cell development is known to be dependent on sufficient zinc supply. Recently a regulatory B cell (Breg) population has been identified, as CD19+IL-10+ B cells, able to regulate immune responses by secretion of anti-inflammatory cytokines, such as IL-10. Due to their promotion of an anti-inflammatory milieu, Bregs could reduce or might even prevent excessive pro-inflammatory responses. Hence, having and maintaining Bregs could be interesting for patients suffering from allergies, asthma, and autoimmune diseases. Therefore, understanding Breg generation, required signaling, and their developmental requirements are important. Since our group could previously show that zinc is important for regulatory T cells, we aimed to determine the effect of zinc deficiency on Breg development from human peripheral blood CD19+ B cells. We observed highest Breg generation with a combined stimulus of CD40L and the toll like receptor (TLR) ligand, CpG-ODN2006. Using this stimulus, we observed that zinc deficient medium significantly decreased Breg generation from purified B cells. This was not seen in Bregs generated from peripheral blood mononuclear cells (PBMCs) without B cell enrichment suggesting a compensatory mechanism. In line with literature, our data also confirms Bregs develop from CD19+ B cells, since total CD19+ frequencies remained unchanged, while Breg frequencies varied between stimuli and zinc media conditions. Our study shows for the first time that zinc deficiency significantly impairs Breg development, which provides an important new perspective for clinical applications and therapeutic strategies.

The nutritional roles of zinc for immune system and COVID-19 patients

Zinc (Zn) is a vital micronutrient that strengthens the immune system, aids cellular activities, and treats infectious diseases. A deficiency in Zn can lead to an imbalance in the immune system. This imbalance is particularly evident in severe deficiency cases, where there is a high susceptibility to various viral infections, including COVID-19 caused by SARS-CoV-2. This review article examines the nutritional roles of Zn in human health, the maintenance of Zn concentration, and Zn uptake. As Zn is an essential trace element that plays a critical role in the immune system and is necessary for immune cell function and cell signaling, the roles of Zn in the human immune system, immune cells, interleukins, and its role in SARS-CoV-2 infection are further discussed. In summary, this review paper encapsulates the nutritional role of Zn in the human immune system, with the hope of providing specific insights into Zn research.

Leukemia cells accumulate zinc for oncofusion protein stabilization

Acute promyelocytic leukemia (APL) and chronic myeloid leukemia (CML) are both hematological malignancies characterized by genetic alterations leading to the formation of oncofusion proteins. The classical chromosomal aberrations in APL and CML result in the PML-RARα and BCR-ABL1 oncofusion proteins, respectively. Interestingly, our flow cytometric analyses revealed elevated free intracellular zinc levels in various leukemia cells, which may play a role in stabilizing oncofusion proteins in leukemia and thus support cell proliferation and malignancy. Long-term zinc deficiency resulted in the degradation of PML-RARα in NB4 cells (APL cell line) and of BCR-ABL1 in K562 cells (CML cell line). This degradation may be explained by increased caspase 3 activity observed in zinc deficient cells, whereas zinc reconstitution normalized the caspase 3 activity and abolished zinc deficiency-induced oncofusion protein degradation. In NB4 cells, fluorescence microscopic images further indicated enlarged and enriched lysosomes during zinc deficiency, suggesting increased rates of autophagy. Moreover, NB4 cells exhibited increased expression of the zinc transporters ZIP2, ZIP10 and ZnT3 during zinc deficiency and revealed excessive accumulation of zinc in contrast to healthy peripheral blood mononuclear cells (PBMCs), when zinc was abundantly available extracellularly. Our results highlight the importance of altered zinc homeostasis for some characteristics in leukemia cells, uncover potential pathways underlying the effects of zinc deficiency in leukemia cells, and provide potential alternative strategies by which oncofusion proteins can be degraded.

Epstein-Barr virus-acquired immunodeficiency in myalgic encephalomyelitis-Is it present in long COVID?

Both myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) and long COVID (LC) are characterized by similar immunological alterations, persistence of chronic viral infection, autoimmunity, chronic inflammatory state, viral reactivation, hypocortisolism, and microclot formation. They also present with similar symptoms such as asthenia, exercise intolerance, sleep disorders, cognitive dysfunction, and neurological and gastrointestinal complaints. In addition, both pathologies present Epstein-Barr virus (EBV) reactivation, indicating the possibility of this virus being the link between both pathologies. Therefore, we propose that latency and recurrent EBV reactivation could generate an acquired immunodeficiency syndrome in three steps: first, an acquired EBV immunodeficiency develops in individuals with "weak" EBV HLA-II haplotypes, which prevents the control of latency I cells. Second, ectopic lymphoid structures with EBV latency form in different tissues (including the CNS), promoting inflammatory responses and further impairment of cell-mediated immunity. Finally, immune exhaustion occurs due to chronic exposure to viral antigens, with consolidation of the disease. In the case of LC, prior to the first step, there is the possibility of previous SARS-CoV-2 infection in individuals with "weak" HLA-II haplotypes against this virus and/or EBV.

Therapeutic effect of trace elements on multiple myeloma and mechanisms of cancer process

In the human body, trace elements and other micronutrients play a vital role in growth, health and immune system function. The trace elements are Iron, Manganese, Copper, Iodine, Zinc, Cobalt, Fluoride, and Selenium. Estimating the serum levels of trace elements in hematologic malignancy patients can determine the severity of the tumor. Multiple myeloma (MM) is a hematopoietic malignancy and is characterized by plasma cell clonal expansion in bone marrow. Despite the advances in treatment methods, myeloma remains largely incurable. In addition to conventional medicine, treatment is moving toward less expensive noninvasive alternatives. One of the alternative treatments is the use of dietary supplements. In this review, we focused on the effect of three trace elements including iron, zinc and selenium on important mechanisms such as the immune system, oxidative and antioxidant factors and cell cycle. Using some trace minerals in combination with approved drugs can increase patients' recovery speed. Trace elements can be used as not only a preventive but also a therapeutic tool, especially in reducing inflammation in hematological cancers such as multiple myeloma. We hope that the prospect of the correct use of trace element supplements in the future could be promising for the treatment of diseases.

Activation of Toll-like receptor 4 by thyroid hormone triggers abnormal B-cell activation

OBJECTIVE

Breakdown of tolerance and abnormal activation of B cells is an important mechanism in the pathogenesis of Graves' disease (GD). High levels of thyroid hormones (THs) play important roles in GD progression. However, the interactions between THs and abnormal activation of B cells remain elusive. This study aimed to explore the effect of high levels of THs on TLR4 expression and abnormal B cell differentiation.

MATERIALS AND METHODS

Blood samples were collected from patients with GD and healthy controls (HCs) to evaluate the frequency of B cells, their subsets, and TLR4 expression in B cells. A high-level T3 mouse model was used to study the interaction between THs and the TLR4 signalling pathway.

RESULTS

We found that the frequencies of CD19+ , CD19+ TLR4+ , CD19+ CD86+ , and CD19+ CD138+ B cells were significantly higher, as were the expression levels of MRP8/MRP14 and MRP6 and MRP8, MRP14, and MRP6 messenger RNA (mRNA) in peripheral blood mononuclear cells in patients with GD. In high-level T3 mice models, the serum MRP8/MRP14 and MRP6 levels and the TLR4 mRNA expression in PBMCs were significantly higher. TLR4 mRNA, protein expression, and cytokines downstream of TLR4, such as myeloid differentiation factor 88 (MyD88) and nuclear transcription factor-κB, were also increased in mouse spleen mononuclear cells.

CONCLUSION

The present study indicated that high levels of T3 can induce abnormal differentiation and activation of B cells by promoting TLR4 overexpression and provide novel insights into the roles of THs in the pathogenesis of GD.

NVS-ZP7-4 inhibits hepatocellular carcinoma tumorigenesis and promotes apoptosis via PI3K/AKT signaling

NVS-ZP7-4 was identified as a novel chemical reagent targeting the zinc input protein ZIP7, which accounts for the zinc surge from the apparatus to the cytoplasm. Since zinc dysregulation is related to multiple diseases, in this study, we aimed to identify the anti-tumor effects of NVS-ZP7-4 and explore the molecular mechanisms of NVS-ZP7-4 in hepatocellular carcinoma (HCC) progression. We found that NVS-ZP7-4 inhibited cell viability, caused cell cycle arrest, induced apoptosis, and inhibited the proliferation, migration, and invasion of HCCLM3 and Huh7 cells. We further investigated the inhibited activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was involved in the antitumor effect of NVS-ZP7-4 in HCC. Furthermore, NVS-ZP7-4 inhibited HCC tumor growth in vivo. The present study demonstrated that NVS-ZP7-4 is a promising therapeutic target for HCC by regulating PI3K/AKT signaling.

The Zinc Transporter SLC39A10 Plays an Essential Role in Embryonic Hematopoiesis

The role of zinc in hematopoiesis is currently unclear. Here, SLC39A10 (ZIP10) is identified as a key zinc transporter in hematopoiesis. The results show that in zebrafish, Slc39a10 is a key regulator of the response to zinc deficiency. Surprisingly, both slc39a10 mutant zebrafish and hematopoietic Slc39a10-deficient mice develop a more severe form of impaired hematopoiesis than animals lacking transferrin receptor 1, a well-characterized iron gatekeeper, indicating that zinc plays a larger role than iron in hematopoiesis, at least in early hematopoietic stem cells (HSCs). Furthermore, it is shown that loss of Slc39a10 causes zinc deficiency in fetal HSCs, which in turn leads to DNA damage, apoptosis, and G₁ cell cycle arrest. Notably, zinc supplementation largely restores colony formation in HSCs derived from hematopoietic Slc39a10-deficient mice. In addition, inhibiting necroptosis partially restores hematopoiesis in mouse HSCs, providing mechanistic insights into the requirement for zinc in mediating hematopoiesis. Together, these findings indicate that SLC39A10 safeguards hematopoiesis by protecting against zinc deficiency-induced necroptosis, thus providing compelling evidence that SLC39A10 and zinc homeostasis promote the development of fetal HSCs. Moreover, these results suggest that SLC39A10 may serve as a novel therapeutic target for treating anemia and zinc deficiency-related disorders.

Zinc promotes cell proliferation via regulating metal-regulatory transcription factor 1 expression and transcriptional activity in pulmonary arterial hypertension

Metal responsive transcription factor 1 (MTF-1) is a zinc-dependent transcription factor involved in the development of pulmonary arterial hypertension (PAH), which is a life-threatening disease characterized by elevated pulmonary artery pressure and pulmonary vascular remodeling. However, little is known about the role and regulatory signaling of MTF-1 in PAH. This study aimed to investigate the effect and mechanism of MTF-1 on the proliferation of pulmonary arterial smooth muscle cells (PASMCs). Several techniques including intracellular-free zinc detected by fluorescent indicator-fluozinc-3-AM, western blot, luciferase reporter, and cell proliferation assay were conducted to perform a comprehensive analysis of MTF-1 in proliferation of PASMCs in PAH. Increased cytosolic zinc was shown in monocrotaline (MCT)-PASMCs and ZnSO₄-treated PASMCs, which led to overexpression and overactivation of MTF-1, followed by the up-regulation of placental growth factor (PlGF). Elevated MTF-1 and PlGF were observed in western blot, and high transcriptional activity of MTF-1 was confirmed by luciferase reporter in ZnSO4-treated cells. Further investigation of cell proliferation revealed a favorable impact of zinc ions on PASMCs proliferation, with the deletion of Mtf-1/Plgf attenuating ZnSO4-induced proliferation. Flow cytometry analysis showed that blockade of PKC signaling inhibited the cell cycle of MCT-PASMCs and ZnSO4-treated PASMCs. The Zinc/PKC/MTF-1/PlGF pathway is involved in the up-regulatory effect on the PASMCs proliferation in the process of PAH. This study provided novel insight into zinc homeostasis in the pathogenesis of PAHs, and the regulation of MTF-1 might be a potential target for therapeutic intervention in PAH.

The LIV-1 Subfamily of Zinc Transporters: From Origins to Present Day Discoveries

This review explains the origin of the LIV-1 family of zinc transporters, paying attention to how this family of nine human proteins was originally discovered. Structural and functional differences between these nine human LIV-1 family members and the five other ZIP transporters are examined. These differences are both related to aspects of the protein sequence, the conservation of important motifs and to the effect this may have on their overall function. The LIV-1 family are dependent on various post-translational modifications, such as phosphorylation and cleavage, which play an important role in their ability to transport zinc. These modifications and their implications are discussed in detail. Some of these proteins have been implicated in cancer which is examined. Furthermore, some additional areas of potential fruitful discovery are discussed and suggested as worthy of examination in the future.

Manganese and the cGAS-STING Pathway in Infectious Mononucleosis Caused by Epstein-Barr Virus Infection

To study the clinical significance of manganese (Mn) in the serum of children with infectious mononucleosis (IM) caused by Epstein-Barr virus (EBV) infection, we analyzed the correlation between Mn and the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway and explored the immune pathogenesis of EBV infection. Children diagnosed with IM comprised the IM group, and healthy children during the same period were selected as the normal control group. Real-time reverse transcription-polymerase chain reaction was used to detect the mRNA expression levels of cGAS, STING, Tank-binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), and related inflammatory factors, and Mn in serum was detected by inductively coupled plasma mass spectrometry. Interferon (IFN)-α and IFN-β expression levels in serum were detected by enzyme-linked immunosorbent assay, and the correlation between Mn levels and clinical manifestations and laboratory tests was analyzed. Mn levels and the expression levels of cGAS, STING, and related inflammatory factors were significantly higher in children with IM than in healthy children. Furthermore, Mn levels in children with IM were positively correlated with the expression levels of cGAS and related inflammatory factors. Thus, Mn, cGAS, STING, and inflammatory cytokines may be involved in the immune mechanism of IM caused by EBV infection.

Zinc dynamics regulate early ovarian follicle development

Zinc fluctuations regulate key steps in late oocyte and preimplantation embryo development; however, roles for zinc in preceding stages in early ovarian follicle development, when cooperative interactions exist between the oocyte and somatic cells, are unknown. To understand the roles of zinc during early follicle development, we applied single cell X-ray fluorescence microscopy, a radioactive zinc tracer, and a labile zinc probe to measure zinc in individual mouse oocytes and associated somatic cells within early follicles. Here, we report a significant stage-specific increase and compartmental redistribution in oocyte zinc content upon the initiation of early follicle growth. The increase in zinc correlates with the increased expression of specific zinc transporters, including two that are essential in oocyte maturation. While oocytes in follicles exhibit high tolerance to pronounced changes in zinc availability, somatic survival and proliferation are significantly more sensitive to zinc chelation or supplementation. Finally, transcriptomic, proteomic, and zinc loading analyses reveal enrichment of zinc targets in the ubiquitination pathway. Overall, these results demonstrate that distinct cell type-specific zinc regulations are required for follicle growth and indicate that physiological fluctuation in the localization and availability of this inorganic cofactor has fundamental functions in early gamete development.

Zinc and COVID-19: Immunity, Susceptibility, Severity and Intervention

During the coronavirus disease 2019 (COVID-19) pandemic and continuing emergence of viral mutants, there has been a lack of effective treatment methods. Zinc maintains immune function, with direct and indirect antiviral activities. Zinc nutritional status is a critical factor in antiviral immune responses. Importantly, COVID-19 and zinc deficiency overlap in high-risk population. Hence, the potential effect of zinc as a preventive and adjunct therapy for COVID-19 is intriguing. Here, this review summarizes the immune and antiviral function of zinc, the relationship between zinc levels, susceptibility, and severity of COVID-19, and the effect of zinc supplementation on COVID-19. Existing studies have confirmed that zinc deficiency was associated with COVID-19 susceptibility and severity. Zinc supplementation plays a potentially protective role in enhancing immunity, decreasing susceptibility, shortening illness duration, and reducing the severity of COVID-19. We recommend that zinc levels should be monitored, particularly in COVID-19 patients, and zinc as a preventive and adjunct therapy for COVID-19 should be considered for groups at risk of zinc deficiency to reduce susceptibility and disease severity.

Glycerol monolaurate inhibition of human B cell activation

Glycerol monolaurate (GML) is a naturally occurring antimicrobial agent used commercially in numerous products and food items. GML is also used as a homeopathic agent and is being clinically tested to treat several human diseases. In addition to its anti-microbial function, GML suppresses immune cell proliferation and inhibits primary human T cell activation. GML suppresses T cell activation by altering membrane dynamics and disrupting the formation of protein clusters necessary for intracellular signaling. The ability of GML to disrupt cellular membranes suggests it may alter other cell types. To explore this possibility, we tested how GML affects human B cells. We found that GML inhibits BCR-induced cytokine production, phosphorylation of signaling proteins, and protein clustering, while also changing cellular membrane dynamics and dysregulating cytoskeleton rearrangement. Although similar, there are also differences between how B cells and T cells respond to GML. These differences suggest that unique intrinsic features of a cell may result in differential responses to GML treatment. Overall, this study expands our understanding of how GML impacts the adaptive immune response and contributes to a broader knowledge of immune modulating monoglycerides.

Impact of Zinc Transport Mechanisms on Embryonic and Brain Development

The trace element zinc (Zn) binds to over ten percent of proteins in eukaryotic cells. Zn flexible chemistry allows it to regulate the activity of hundreds of enzymes and influence scores of metabolic processes in cells throughout the body. Deficiency of Zn in humans has a profound effect on development and in adults later in life, particularly in the brain, where Zn deficiency is linked to several neurological disorders. In this review, we will summarize the importance of Zn during development through a description of the outcomes of both genetic and early dietary Zn deficiency, focusing on the pathological consequences on the whole body and brain. The epidemiology and the symptomology of Zn deficiency in humans will be described, including the most studied inherited Zn deficiency disease, Acrodermatitis enteropathica. In addition, we will give an overview of the different forms and animal models of Zn deficiency, as well as the 24 Zn transporters, distributed into two families: the ZIPs and the ZnTs, which control the balance of Zn throughout the body. Lastly, we will describe the TRPM7 ion channel, which was recently shown to contribute to intestinal Zn absorption and has its own significant impact on early embryonic development.

Rebalancing the unbalanced aged immune system - A special focus on zinc

Nowadays, aging is understood as a dynamic and multifaceted dysregulation process that spares almost no human organ or cell. The immune system being among the most affected, it has been shown predominantly that its integrity determines the tightrope walk between the difference of escaping or suffering from age-related diseases. Next to drug-based anti-aging strategies, micronutrient intervention may represent an emerging but less radical way to slow immune aging. While a sufficient supply of a variety of micronutrients is undeniably important, adequate intake of the trace element zinc appears to tower over others in terms of reaching old age. Inconveniently, zinc deficiency prevalence among the elderly is high, which in turn contributes to increased susceptibility to infection, decreased anti-tumor immunity as well as attenuated response to vaccination. Driven by this research, this review aims to provide a comprehensive and up-to-date overview of the various rebalancing capabilities of zinc in the unbalanced immune system of the elderly. This includes an in-depth and cell type-centered discussion on the role of zinc in immunosenescence and inflammaging. We further address upcoming translational aspects e.g. how zinc deficiency promotes the flourishing of certain pathogenic taxa of the gut microbiome and how zinc supply counteracts such alterations in a manner that may contribute to longevity. In the light of the ongoing COVID-19 pandemic, we also briefly review current knowledge on the interdependency between age, zinc status, and respiratory infections. Based on two concrete examples and considering the latest findings in the field we conclude our remarks by outlining tremendous parallels between suboptimal zinc status and accelerated aging on the one hand and an optimized zinc status and successful aging on the other hand.

HIV, HSV, SARS-CoV-2 and Ebola Share Long-Term Neuropsychiatric Sequelae

Long COVID, in which disease-related symptoms persist for months after recovery, has led to a revival of the discussion of whether neuropsychiatric long-term symptoms after viral infections indeed result from virulent activity or are purely psychological phenomena. In this review, we demonstrate that, despite showing differences in structure and targeting, many viruses have highly similar neuropsychiatric effects on the host. Herein, we compare severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human immunodeficiency virus 1 (HIV-1), Ebola virus disease (EVD), and herpes simplex virus 1 (HSV-1). We provide evidence that the mutual symptoms of acute and long-term anxiety, depression and post-traumatic stress among these viral infections are likely to result from primary viral activity, thus suggesting that these viruses share neuroinvasive strategies in common. Moreover, it appears that secondary induced environmental stress can lead to the emergence of psychopathologies and increased susceptibility to viral (re)infection in infected individuals. We hypothesize that a positive feedback loop of virus-environment-reinforced systemic responses exists. It is surmised that this cycle of primary virulent activity and secondary stress-induced reactivation, may be detrimental to infected individuals by maintaining and reinforcing the host's immunocompromised state of chronic inflammation, immunological strain, and maladaptive central-nervous-system activity. We propose that this state can lead to perturbed cognitive processing and promote aversive learning, which may manifest as acute, long-term neuropsychiatric illness.

Intracellular zinc during cell activation and zinc deficiency

INTRODUCTION

Zinc is an essential trace element having manifold functions within living cells. Zinc deficiency but also zinc excess impairs cell-specific functions whereas a balanced zinc level is required for an adequate cell behavior.

MATERIAL AND METHODS

This study deals with the impact of cellular priming due to stimulation with interleukin (IL)-1, IL-2, IL-4, IL-6 or the chemokine CXCL12a and its subsequent influence on the intracellular free zinc concentration. Since cellular priming and activation is essential for proper immunological reactions, and across that highly cell-type specific, we investigated T cells, B cells, and peripheral blood mononuclear cells (PBMCs). Additionally, alterations of the intracellular zinc content was investigated by inducing zinc deficiency using the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) with subsequent re-supplementation of zinc, hence generating an intracellular zinc flux. Evaluation of zinc staining with FluoZin3-AM, Zinpyr-1 and Zinquin was done by flow cytometry or by fluorescence microscopy.

RESULTS

Our results indicate that cellular priming for different periods of time (10 minutes/one hour) causes decreased intracellular free zinc concentrations in the FluoZin3-AM staining and increased zinc concentrations stained with Zinpyr-1. Furthermore, zinc supplementation after induced zinc deficiency leads to a fast and excessive rise of the intracellular free zinc levels in most cellular compartments.

CONCLUSION

Our study emphasizes the importance of zinc homeostasis and zinc distribution during cellular priming and for certain signaling cascades especially in T and B cells. Moreover, we demonstrated that zinc re-supplementation of zinc deficient cells results in significantly elevated intracellular free zinc concentrations compared to untreated controls. Hence, this underlines the need of a balanced zinc homeostasis for proper immune cell function.

The role of zinc transporter proteins as predictive and prognostic biomarkers of hepatocellular cancer

Identification of the key processes involved in the tumor progression, malignancy and the molecular factors which are responsible for the transition of the cirrhotic cells to the tumor cells, contribute to the detection of biomarkers for diagnosis of hepatocellular carcinoma (HCC) at an early stage. According to clinical data, HCC is mostly characterized by a significant decrease in zinc levels. It is strongly implied that zinc deficiency is the major event required in the early stages of tumor formation and development of malignancy. Due to this reason, the definition of the molecular players which have a role in zinc homeostasis and cellular zinc level could give us a clue about the transition state of the cirrhosis to hepatic tumor formation. Despite the well-known implications of zinc in the development of HCCthe correlation of the expression of zinc transporter proteins with tumor progression and malignancy remain largely unknown. In the present study, we evaluated in detail the relationship of zinc deficiency on the prognosis of early HCC patients. In this study, we aimed to test the potential zinc transporters which contribute tothe transformation of cirrhosis to HCCand the progression of HCC. Among the 24 zinc transporter proteins, the proteins to be examined were chosen by using Gene Expression Profiling Interactive Analysis (GEPIA) webpage and RNA-seq analysis using TCGA database. ZIP14 and ZIP5 transporters were found as common differentially expressed genes from both bioinformatic analyses. ZnT1, ZnT7 and ZIP7 transporters have been associated with tumor progression. Relative abundance of ZnT1, ZIP5 and ZIP14 protein level was determined by immunohistochemistry (IHC) in surgically resected liver specimens from 16 HCC patients at different stages. IHC staining intensity was analyzed by using ImageJ software and scored with the histological scoring (H-score) method. The staining of ZnT1 was significantly higher in Grade III comparing to Grade II and Grade I. On the contrary, ZIP14 staining decreased almost 10-foldcomparing to Grade Iand Grade II. ZIP5 staining was detected almost 2-fold higher in cirrhosis than HCC. But ZnT1 staining was observed almost 3-fold lower in cirrhosis comparing to HCC. Intracellular free zinc level was measured by flow cytometry in Hep40 and Snu398 cells using FluoZin-3 dye. The intracellular free zinc level was almost 9-fold decreased in poor differentiated Snu398 HCC cells comparing to well differentiated Hep40 HCC cells.This report establishes for the first time the correlation between the expression pattern of ZIP14, ZnT1 and ZIP5 and significant zinc deficiency which occurs concurrently with the advancing of malignancy. Our results provide new molecular insight into ZnT1, ZIP14 and ZIP5 mediated regulation of cellular zinc homeostasis and indicate that zinc transporters might be important factors and events in HCC malignancy, which can lead to the development of early biomarkers.

Cancer therapeutic strategies based on metal ions

As a necessary substance to maintain the body's normal life activities, metal ions are ubiquitous in organisms and play a major role in various complex physiological and biochemical processes, such as material transportation, energy conversion, information transmission, metabolic regulation, etc. Their abnormal distribution/accumulation in cells can interfere with these processes, causing irreversible physical damage to cells or activating biochemical reactions to induce cell death. Therefore, metal ions can be exploited against a wide spectrum of cancers with high efficiency and without drug resistance, which can effectively inhibit the growth of cancer cells by triggering biocatalysis, breaking the osmotic balance, affecting metabolism, interfering with signal transduction, damaging DNA, etc. This perspective systematically summarizes the latest research progress of metal ion-based anti-tumor therapy, and emphasizes the challenges and development directions of this type of therapeutic strategy, hoping to provide a general implication for future research.

Zinc Favors Triple-Negative Breast Cancer's Microenvironment Modulation and Cell Plasticity

Triple-negative breast cancer (TNBC) tends to metastasize to the brain, a step that worsens the patient’s prognosis. The specific hallmarks that determine successful metastasis are motility and invasion, microenvironment modulation, plasticity, and colonization. Zinc, an essential trace element, has been shown to be involved in all of these processes. In this work, we focus our attention on the potential role of zinc during TNBC metastasis. We used MDA-MB-BrM2 (BrM2) cells, a brain metastasis model derived from the parental TNBC cell line MDA-MB-231. Our studies show that BrM2 cells had double the zinc content of MDA-MB-231 cells. Moreover, exploring different metastatic hallmarks, we found that the zinc concentration is especially important in the microenvironment modulation of brain metastatic cells, enhancing the expression of SerpinB2. Furthermore, we show that zinc promotes the tumorigenic capacity of breast cancer stem cells. In addition, by causing a disturbance in MDA-MB-231 zinc homeostasis by overexpressing the Zip4 transporter, we were able to increase tumorigenicity. Nevertheless, this strategy did not completely recapitulate the BrM2 metastatic phenotype. Altogether, our work suggests that zinc plays an important role in the transformative steps that tumoral cells take to acquire tumorigenic potential and niche specificity.

Dietary and Physiological Effects of Zinc on the Immune System

Evidence for the importance of zinc for all immune cells and for mounting an efficient and balanced immune response to various environmental stressors has been accumulating in recent years. This article describes the role of zinc in fundamental biological processes and summarizes our current knowledge of zinc's effect on hematopoiesis, including differentiation into immune cell subtypes. In addition, the important role of zinc during activation and function of immune cells is detailed and associated with the specific immune responses to bacteria, parasites, and viruses. The association of zinc with autoimmune reactions and cancers as diseases with increased or decreased immune responses is also discussed. This article provides a broad overview of the manifold roles that zinc, or its deficiency, plays in physiology and during various diseases. Consequently, we discuss why zinc supplementation should be considered, especially for people at risk of deficiency. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Update on the multi-layered levels of zinc-mediated immune regulation

The significance of zinc for an efficient immune response is well accepted. During zinc deficiency, an increase in the myeloid to lymphoid immune cells ratio was observed. This results in a disturbed balance of pro- and anti-inflammatory processes as well as defects in tolerance during infections. Consequently, instead of efficiently defending the body against invading pathogens, damage of host cells is frequently observed. This explains the increased susceptibility to infections and their severe progression observed for zinc deficient individuals as well as the association of autoimmune diseases with low serum zinc levels. Together with the advances in techniques for investigating cellular development, communication and intracellular metabolism, our understanding of the mechanisms underlying the benefits of zinc for human health and the detriments of zinc deficiency has much improved. As analyses of the zinc status and effects of zinc supplementation were more frequently included into clinical studies, our knowledge of the association of zinc deficiency to a variety of diseases was strongly improved. Still there are several areas in zinc biology that require further in-depth investigation such as the interaction with other nutritional elements, the direct association between zinc transportation, membrane-structure, receptors, and signaling as well as its role in cell degeneration. This article will describe our current understanding of the role of zinc during the immune response focusing on the most recent findings and underlying mechanisms. Research questions that need to be addressed in the future will be discussed as well.

Toward unzipping the ZIP metal transporters: structure, evolution, and implications on drug discovery against cancer

The Zrt-/Irt-like protein (ZIP) family consists of divalent metal transporters, ubiquitous in all kingdoms of life. Since the discovery of the first ZIPs in the 1990s, the ZIP family has been expanding to contain tens of thousands of members playing key roles in uptake and homeostasis of life-essential trace elements, primarily zinc, iron and manganese. Some family members are also responsible for toxic metal (particularly cadmium) absorption and distribution. Their central roles in trace element biology, and implications in many human diseases, including cancers, have elicited interest across multiple disciplines for potential applications in biomedicine, agriculture and environmental protection. In this review and perspective, selected areas under rapid progress in the last several years, including structural biology, evolution, and drug discovery against cancers, are summarised and commented. Future research to address the most prominent issues associated with transport and regulation mechanisms are also discussed.

The role of labile Zn2+ and Zn2+-transporters in the pathophysiology of mitochondria dysfunction in cardiomyocytes

An important energy supplier of cardiomyocytes is mitochondria, similar to other mammalian cells. Studies have demonstrated that any defect in the normal processes controlled by mitochondria can lead to abnormal ROS production, thereby high oxidative stress as well as lack of ATP. Taken into consideration, the relationship between mitochondrial dysfunction and overproduction of ROS as well as the relation between increased ROS and high-level release of intracellular labile Zn²⁺, those bring into consideration the importance of the events related with those stimuli in cardiomyocytes responsible from cellular Zn²⁺-homeostasis and responsible Zn²⁺-transporters associated with the Zn²⁺-homeostasis and Zn²⁺-signaling. Zn²⁺-signaling, controlled by cellular Zn²⁺-homeostatic mechanisms, is regulated with intracellular labile Zn²⁺ levels, which are controlled, especially, with the two Zn²⁺-transporter families; ZIPs and ZnTs. Our experimental studies in mammalian cardiomyocytes and human heart tissue showed that Zn²⁺-transporters localizes to mitochondria besides sarco(endo)plasmic reticulum and Golgi under physiological condition. The protein levels as well as functions of those transporters can re-distribute under pathological conditions, therefore, they can interplay among organelles in cardiomyocytes to adjust a proper intracellular labile Zn²⁺ level. In the present review, we aimed to summarize the already known Zn²⁺-transporters localize to mitochondria and function to stabilize not only the cellular Zn²⁺ level but also cellular oxidative stress status. In conclusion, one can propose that a detailed understanding of cellular Zn²⁺-homeostasis and Zn²⁺-signaling through mitochondria may emphasize the importance of new mitochondria-targeting agents for prevention and/or therapy of cardiovascular dysfunction in humans.

Galvanization of Protein-Protein Interactions in a Dynamic Zinc Interactome

The presence of Zn²⁺ at protein-protein interfaces modulates complex function, stability, and introduces structural flexibility/complexity, chemical selectivity, and reversibility driven in a Zn²⁺-dependent manner. Recent studies have demonstrated that dynamically changing Zn²⁺ affects numerous cellular processes, including protein-protein communication and protein complex assembly. How Zn²⁺-involved protein-protein interactions (ZPPIs) are formed and dissociate and how their stability and reactivity are driven in a zinc interactome remain poorly understood, mostly due to experimental obstacles. Here, we review recent research advances on the role of Zn²⁺ in the formation of interprotein sites, their architecture, function, and stability. Moreover, we underline the importance of zinc networks in intersystemic communication and highlight bioinformatic and experimental challenges required for the identification and investigation of ZPPIs.

The Potential Impact of Zinc Supplementation on COVID-19 Pathogenesis

During the current corona pandemic, new therapeutic options against this viral disease are urgently desired. Due to the rapid spread and immense number of affected individuals worldwide, cost-effective, globally available, and safe options with minimal side effects and simple application are extremely warranted. This review will therefore discuss the potential of zinc as preventive and therapeutic agent alone or in combination with other strategies, as zinc meets all the above described criteria. While a variety of data on the association of the individual zinc status with viral and respiratory tract infections are available, study evidence regarding COVID-19 is so far missing but can be assumed as was indicated by others and is detailed in this perspective, focusing on re-balancing of the immune response by zinc supplementation. Especially, the role of zinc in viral-induced vascular complications has barely been discussed, so far. Interestingly, most of the risk groups described for COVID-19 are at the same time groups that were associated with zinc deficiency. As zinc is essential to preserve natural tissue barriers such as the respiratory epithelium, preventing pathogen entry, for a balanced function of the immune system and the redox system, zinc deficiency can probably be added to the factors predisposing individuals to infection and detrimental progression of COVID-19. Finally, due to its direct antiviral properties, it can be assumed that zinc administration is beneficial for most of the population, especially those with suboptimal zinc status.

Cilostazol restores autophagy flux in bafilomycin A1-treated, cultured cortical astrocytes through lysosomal reacidification: roles of PKA, zinc and metallothionein 3

Cilostazol, a phosphodiesterase 3 inhibitor, reduces the amyloid-beta (Aβ) burden in mouse models of Alzheimer disease by as yet unidentified mechanisms. In the present study, we examined the possibility that cilostazol ameliorates lysosomal dysfunction. Astrocytes treated with bafilomycin A1 (BafA1) exhibited markedly reduced DND-189 and acridine orange (AO) fluorescence, indicating reduced lysosomal acidity. In both cases, BafA1-induced alkalization was reversed by addition of cilostazol, dibutyryl cAMP or forskolin. All three agents significantly increased free zinc levels in lysosomes, and addition of the zinc chelator TPEN abrogated lysosomal reacidification. These treatments did not raise free zinc levels or reverse BafA1-mediated lysosomal alkalization in metallothionein 3 (Mt3)-null astrocytes, indicating that the increases in zinc in astrocytes were derived mainly from Mt3. Lastly, in FITC-Aβ-treated astrocytes, cilostazol reversed lysosomal alkalization, increased cathepsin D activity, and reduced Aβ accumulation in astrocytes. Cilostazol also reduced mHtt aggregate formation in GFP-mHttQ74–expressing astrocytes. Collectively, our results present the novel finding that cAMP/PKA can overcome the v-ATPase blocking effect of BafA1 in a zinc- and Mt3-dependent manner.

Beyond the CRAC: Diversification of ion signaling in B cells

Although calcium signaling and the important role of calcium release–activated calcium channels is well recognized in the context of immune cell signaling, there is a vast diversity of ion channels and transporters that regulate the entry of ions beyond calcium, including magnesium, zinc, potassium, sodium, and chloride. These ions play a critical role in numerous metabolic and cellular processes. The importance of ions in human health and disease is illustrated by the identification of primary immunodeficiencies in patients with mutations in genes encoding ion channels and transporters, as well as the immunological defects observed in individuals with nutritional ion deficiencies. Despite progress in identifying the important role of ions in immune cell development and activation, we are still in the early stages of exploring the diversity of ion channels and transporters and mechanistically understanding the role of these ions in immune cell biology. Here, we review the biology of ion signaling in B cells and the identification of critical ion channels and transporters in B‐cell development, activation, and differentiation into effector cells. Elucidating the role of ion channels and transporters in immune cell signaling is critical for expanding the repertoire of potential therapeutics for the treatment of immune disorders. Moreover, increased understanding of the role of ions in immune cell function will enhance our understanding of the potentially serious consequences of ion deficiencies in human health and disease.

Micronutrients in autoimmune diseases: possible therapeutic benefits of zinc and vitamin D

A functional immune system is essential for healthy life. This is achieved by the coordinate activation and interaction of different immune cells. One should be aware that activation of the immune response is as important as its deactivation when the pathogens are cleared, as otherwise host tissue can be damaged up to life-threatening levels. Autoimmune diseases (AID) represent a phenomenon of immune cells attacking host cells and tissue. Five to eight percent of the world's population are currently affected by 80-100 AID. In recent years, the incidence has been constantly increasing, reaching alarmingly high numbers particularly for type 1 diabetes mellitus, Crohn's disease, rheumatoid arthritis, Sjogren's syndrome and multiple sclerosis. This indicates a higher societal burden of AID for the future. This article provides an overview of general concepts of triggers and underlying mechanisms leading to self-destruction. Lately, several original concepts of disease etiology were revised, and there is a variety of hypotheses on triggers, underlying mechanisms and preventive actions. This article concentrates on the importance of nutrition, especially zinc and vitamin D, for balancing the immune function. Homespun nutritional remedies seem to reenter today's therapeutic strategies. Current treatment approaches are largely symptomatic or suppress the immune system. However, recent studies reveal significant benefits of nutrition-related therapeutic approaches including prevention and treatment of established disease, which offer a cost-efficient and trigger-unspecific alternative addressing balancing rather than suppression of the immune system. Zinc and vitamin D are currently the best studied and most promising candidates for therapeutic intervention.