Magnesium Transporter 1 Research Articles

MicroRNA-1289 Functions as a Novel Tumor Suppressor in Oral Squamous Cell Carcinoma.

Recently, numerous tumor-suppressive microRNAs (TS-miRs) have been identified in human malignancies. Here, we attempted to identify novel TS-miRs in oral squamous cell carcinoma (OSCC). First, we transfected human OSCC cells individually with 968 synthetic miRs mimicking human mature miRs individually, and the growth of these cells was evaluated using the WST-8 assay. Five miR mimics significantly reduced the cell growth rate by less than 30%, and the miR-1289 mimic had the most potent growth inhibitory effect among these miRs. Subsequently, we assessed the in vivo growth-inhibitory effects of miR-1289 using a mouse model. The administration of the miR-1289 mimic-atelocollagen complex significantly reduced the size of subcutaneously xenografted human OSCC tumors. Next, we investigated the expression of miR-1289 in OSCC tissues using reverse transcription-quantitative PCR. The expression level of miR-1289 was significantly lower in OSCC tissues than in the adjacent normal oral mucosa. Furthermore, 15 genes were identified as target genes of miR-1289 via microarray and Ingenuity Pathway Analysis (IPA) microRNA target filtering. Among these genes, the knockdown of magnesium transporter 1 (MAGT1) resulted in the most remarkable cell growth inhibition in human OSCC cells. These results suggested that miR-1289 functions as a novel TS-miR in OSCC and may be a useful therapeutic tool for patients with OSCC.

MAGT1 Deficiency Dysregulates Platelet Cation Homeostasis and Accelerates Arterial Thrombosis and Ischemic Stroke in Mice.

MAGT1 (magnesium transporter 1) is a subunit of the oligosaccharide protein complex with thiol-disulfide oxidoreductase activity, supporting the process of N-glycosylation. MAGT1 deficiency was detected in human patients with X-linked immunodeficiency with magnesium defect syndrome and congenital disorders of glycosylation, resulting in decreased cation responses in lymphocytes, thereby inhibiting the immune response against viral infections. Curative hematopoietic stem cell transplantation of patients with X-linked immunodeficiency with magnesium defect causes fatal bleeding and thrombotic complications. We studied the role of MAGT1 deficiency in platelet function in relation to arterial thrombosis and hemostasis using several in vitro experimental settings and in vivo models of arterial thrombosis and transient middle cerebral artery occlusion model of ischemic stroke. MAGT1-deficient mice (Magt1-/y) displayed accelerated occlusive arterial thrombus formation in vivo, a shortened bleeding time, and profound brain damage upon focal cerebral ischemia. These defects resulted in increased calcium influx and enhanced second wave mediator release, which further reinforced platelet reactivity and aggregation responses. Supplementation of MgCl2 or pharmacological blockade of TRPC6 (transient receptor potential cation channel, subfamily C, member 6) channels, but not inhibition of store-operated calcium entry, normalized the aggregation responses of Magt1-/y platelets to the control level. GP (glycoprotein) VI activation of Magt1-/y platelets resulted in hyperphosphorylation of Syk (spleen tyrosine kinase), LAT (linker for activation of T cells), and PLC (phospholipase C) γ2, whereas the inhibitory loop regulated by PKC (protein kinase C) was impaired. A hyperaggregation response to the GP VI agonist was confirmed in human platelets isolated from a MAGT1-deficient (X-linked immunodeficiency with magnesium defect) patient. Haploinsufficiency of TRPC6 in Magt1-/y mice could normalize GP VI signaling, platelet aggregation, and thrombus formation in vivo. These results suggest that MAGT1 and TRPC6 are functionally linked. Therefore, deficiency or impaired functionality of MAGT1 could be a potential risk factor for arterial thrombosis and stroke.

MAGT1 deficiency in XMEN disease is associated with severe platelet dysfunction and impaired platelet glycoprotein N-glycosylation

BackgroundX-linked immunodeficiency with magnesium defect, Epstein–Barr virus infection, and neoplasia (XMEN) disease is a primary immunodeficiency due to loss-of-function mutations in the gene encoding for magnesium transporter 1 (MAGT1). Furthermore, as MAGT1 is involved in the N-glycosylation process, XMEN disease is classified as a congenital disorder of glycosylation. Although XMEN-associated immunodeficiency is well described, the mechanisms underlying platelet dysfunction and those responsible for life-threatening bleeding events have never been investigated. ObjectivesTo assess platelet functions in patients with XMEN disease. MethodsTwo unrelated young boys, including one before and after hematopoietic stem cell transplantation, were investigated for their platelet functions, glycoprotein expression, and serum and platelet-derived N-glycans. ResultsPlatelet analysis highlighted abnormal elongated cells and unusual barbell-shaped proplatelets. Platelet aggregation, integrin αIIbβ3 activation, calcium mobilization, and protein kinase C activity were impaired between both patients. Strikingly, platelet responses to protease-activated receptor 1 activating peptide were absent at both low and high concentrations. These defects were also associated with decreased molecular weights of glycoprotein Ibα, glycoprotein VI, and integrin αIIb due to partial impairment of N-glycosylation. All these defects were corrected after hematopoietic stem cell transplantation. ConclusionOur results highlight prominent platelet dysfunction related to MAGT1 deficiency and defective N-glycosylation in several platelet proteins that could explain the hemorrhages reported in patients with XMEN disease.

An Unexpected Diagnosis of MAGT1 Deficiency in a Patient with CVID-like Features, Molluscum Contagiosum and Atopy

Case DescriptionA 6-year-old boy presented to the immunology clinic with recurrent infections. He started to have recurrent otitis media at the age of 18 months. He also had multiple sinus infections and 3–4 episodes of pneumonia. Immunologic evaluation revealed an IgG of 498 (ref 608–1229 mg/dL), an IgA of 20.8 (ref 33–200 mg/dL) and an impaired response to the Streptococcus pneumoniae vaccine. T and B lymphocyte counts were normal. He was started on subcutaneous immunoglobulin replacement therapy after which his IgG level normalized and his frequency of sinopulmonary infections improved. He also has a history of eczema, chronic cough and environmental allergies for which he receives allergen-specific subcutaneous immunotherapy in addition to treatment with an inhaled corticosteroid and omalizumab. The patient also had persistent skin warts on his hands and extensive molluscum contagiosum lesions. He underwent targeted genetic testing for a primary immunodeficiency which revealed a hemizygous pathogenic variant in the magnesium transporter 1 (MAGT1) gene (c.580dup; p.Ser194Phefs*3). This variant is a duplication at nucleotide position 580 that creates a premature stop codon 3 amino acids downstream from this location. The patient subsequently underwent a carbohydrate deficient transferrin test (CDT) for congenital disorders of glycosylation (CDG) that revealed moderately elevated transferrin mono-oligosaccharide to di-oligosaccharide and Apo CIII-1/Apo CIII-2 ratios, consistent with the diagnosis of MAGT1-CDG (XMEN; X-linked immunodeficiency with magnesium defect, EBV infection, and neoplasia). Additionally, NKG2D surface expression was reduced by ~90% on the CD8T cells, and by ~85% on the NK cells in the patient sample compared to the control sample assessed in parallel. The patient continues to test negative for EBV infection by PCR. ConclusionXMEN disease (OMIM number 300853) is a rare, combined immunodeficiency resulting from a mutation in the magnesium transporter 1 gene (MAGT1) located on the X chromosome. Only 36 patients have been reported to have this disease thus far. While the clinical phenotype is variable, the disease is often associated with EBV infection. This case is unique in that the patient was diagnosed due to a history of severe warts, atopy, and hypogammaglobulinemia in the absence of EBV infection.

Epigenetic activation of the TUSC3 gene as a potential therapy for XMEN disease

"X-linked MAGT1 deficiency with increased susceptibility to EBV infection and N-linked glycosylation defect" (XMEN) disease is a rare combined immunodeficiency (CID) caused by loss of function mutations in the magnesium transporter 1 (MAGT1) gene. MAGT1 deficiency impairs magnesium transport and the N-glycosylation of a panel of proteins, which subsequently abolishes the expression of key immune receptors such as Natural-Killer Group 2, member D (NKG2D). These effects induce immune system abnormalities, chronic EBV infection and neoplasia. Recent research shows that MAGT1 and tumor candidate suppressor 3 (TUSC3) share high sequence and functional similarity. We sought to investigate the feasibility of activating TUSC3 expression to provide a potential therapeutic strategy for XMEN disease. The expression profiles of MAGT1 and TUSC3 were analyzed using multiple databases, RT‒PCR, and western blot. The effects of decitabine and panobinostat on the regulation of TUSC3 expression were explored in both MAGT1 knock-out (KO)/patient-derived lymphocytes and MAGT1 KO hepatocytes. Although TUSC3 is widely expressed, it is undetectable specifically in the immune system and liver, consistent with the main diseased tissues in XMEN patients. CRISPR/Cas9-mediated KO of MAGT1 in the NKL cell line successfully mimicked the phenotypes of XMEN patient-derived lymphocytes, and exogenous expression of TUSC3 rescued the deficiencies in KO NKL cells. Using this in vitro model, we identified two epigenetic drugs, decitabine and panobinostat, by screening. Combination treatment using these two drugs significantly upregulated TUSC3 expression and rescued the immune and liver abnormalities. Epigenetic activation of TUSC3 expression constitutes an effective therapeutic strategy for XMEN disease.

CD5 B-Cell Predominant Primary Immunodeficiency: Part of the Spectrum of MAGT1 Deficiency.

Selective anti-polysaccharide antibody deficiency (SPAD) with CD5 B-cell predominance and autoimmune phenomena was identified in a male cohort first reported by Antall et al in 1999. The phenotypically likewise and genotypically identical X-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia (XMEN) disease was defined as a novel primary immunodeficiency (PID) in 2011. Recent studies of the magnesium transporter 1 (MAGT1) gene mutation reveal glycosylation defects contributing to more phenotypic variance than the "XMEN" title pathologies. The updated title, "X-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect," was proposed in 2020. To reflect the patient population more accurately, a prospective classification update may consider MAGT1 glycobiological errors contributing to phenotypic variance but also pre-genetic testing era reports with CD5 B-cell predominance. Patient 1 from Antall et al presented at 28 years of age for further immunological evaluation of his CD5/CD19 B-cell predominance diagnosed at 5 years old. Immune re-evaluation done through flow cytometry and next-generation sequencing. Flow cytometry B-cell phenotyping revealed persistent CD5+CD19+ (93%). Flow cytometric histogram quantified reduced activator CD16+CD56+ natural killer and CD8+ T-cell receptor, Group 2, Member D (NKG2D) glycoprotein expression. A c.923-1_934 deletion loss of function mutation was identified in the MAGT1 gene. We suggest the novel PID XMEN, based on its CD5 B-cell predominance, had been discovered and reported over a decade earlier as CD5+ PID based on the MAGT1 mutation found in the same. We encourage consideration of combining these labels and recent findings to offer the most accurate classification of this disease.

Highly Efficient & Specific Repair of MAGT1 Mutation in Xmen Patient T Cells and Hematopoietic Stem Cells

Introduction: X-linked immunodeficiency with magnesium defect, Epstein-Barr virus (EBV) infection, and neoplasia (XMEN) is a congenital glycosylation disorder with combined immune deficiency due to Magnesium Transporter 1 (MAGT1) mutations. Defective glycosylation of Natural Killer Group 2D (NKG2D), an activating receptor expressed on CD8 and NK cells critical for cytotoxicity, results in EBV lymphoproliferative disease and an inverted CD4:CD8 ratio in many XMEN patients. Oral magnesium supplementation for XMEN patients was not helpful, and hematopoietic stem cell transplants (HSCT) are complicated by high mortality. CRISPR-Cas9-AAV inserts MAGT1 specifically at endogenous locus but relies on double strand DNA breaks and adeno-associated virus donor that triggers DNA damage response. To address this, we evaluated base editing approach to repair a MAGT1 mutation that affects multiple patients with XMEN disease. We observed highly efficient mutation repair of XMEN T cells (75.5%) and hematopoietic stem cells (71.9%) to restore MAGT1 function and persistence of gene correction following transplant into immunodeficient mice. Materials and methods: Peripheral blood hematopoietic stem cells (HSPCs, CD34+) and mononuclear cells (PBMC) were collected from XMEN patients and healthy donors (HD) after G-CSF and plerixafor mobilization. PBMCs were stimulated (anti-CD3/anti-CD28, IL-2 (100 IU/mL), in ImmunoCult™-XF T cell expansion medium for 5-7 days prior to editing. HSPCs were cultured in StemSpan™ SFEM II Stem Cell Factor, Thrombopoietin, Fms-like tyrosine kinase 3 ligand (all 100ng/mL) and UM171 for two days prior to editing. Base editing is performed by electroporation (MaxCyte Inc.) of cells with ABE8e SpRY (CELLSCRIPT LLC.) and synthetic guide (Synthego) RNAs. For in vitro killing activity, T cells were co-cultured with EBV-B cells at a ratio of 1:1 for 48 hours and analyzed for apoptosis (Apoptracker Green+ 7AAD-), necrosis (Apoptracker Green+ 7AAD+) and degranulation (CD8+ CD107a+). HSPCs were transplanted into mice two days after EP and harvested 17-20 weeks after transplant. Results:Base editing of XMEN T cells: Flow cytometric analysis 2 days post BE show restored expression of biomarker NKG2D in XMEN CD8+ T cells (75.5%) compared to HD (93.2%) and naïve XMEN (2.39%). CD8+ cytotoxic activity against EBV-B cells was restored in BE XMEN patient cells; as indicated by increased apoptosis (BE: 6.78%, naïve: 4.82%, HD: 8.17%), necrosis (BE: 9.35%, naïve: 4.54%, HD: 7.19%), and degranulation (BE: 22.80%, naïve: 15.50%, HD: 21.40%), compared to naïve MAGT1 CD8+ T cells.In an in vivo tumor model, BE XMEN T cells injected into mice with induced luminescent EBV-B cell tumors lysed tumors and reduced average bioluminescence flux (photons/sec) (7 weeks) (8.23 × 107 ± 1.06 × 108) compared to naïve T cells (3.39 × 109 ± 2.22 × 109 and HD T cells (1.45 × 109 ± 2.22 × 109). Base editing of HSPCs: Immunodeficient NSGS pups transplanted with BE XMEN HSPCs engrafted and differentiated normally into lymphocytes with a normalized CD4:CD8 ratio in spleen (BE: 0.79 ± 0.14, naïve: 3.45 ± 1.1, HD: 1.3 ± 0.40) and peripheral blood (BE: 2.16 ± 0.84, naïve: 5.56 ± 2.32, HD: 1.79 ± 0.70) (Fig 1a). Importantly, restoration of biomarker NKG2D expression selectively on CD8+ T cells in spleen (BE: 80.5% ± 8.61%, naïve: 3.63% ± 1.45%, HD: 68.9% ± 10.32%) and peripheral blood (BE: 86.1% ± 2.88%, naïve: 2.25% ± 1.45%, HD: 62.6% ± 12.44%) (Fig 1b) confirmed correction of MAGT1 function in the glycosylation of critical NKG2D protein. High throughput targeted sequencing of on-target locus shows minimal bystander edits and additional off-target analysis is ongoing. Conclusion: Our data show highly efficient and specific base editing repair of MAGT1 mutation in XMEN T lymphocytes and CD34+ HSPCs. BE XMEN T cells increased cytotoxic activity in vitro and killing of tumor cells in mice. In vivo studies with mice transplanted with BE CD34+ HSPCs also confirm long term engraftment and differentiation into CD8+ T cells with restored NKG2D necessary for activation and cytolytic activity of CD8+ T and NK cells. The highly efficient and specific correction with base editing holds great promise for gene therapy for XMEN disease. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Early-Onset Merkel Cell Carcinoma is Associated with Germline Defects in DNA Repair Genes and a Rare Immunodeficiency

Background and aims: Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer associated with immunosuppression and advanced age. Only 10% of patients present with MCC below age 50, and fewer than 0.1% present below age 30. Two patients with early-onset MCC (ages 14 and 22) were identified among patients followed at the NIH for X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (XMEN) disease, which is caused by mutations in the magnesium transporter 1 (MAGT1) gene.

33904 Early onset Merkel cell carcinoma in patients with XMEN disease

Background: Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer frequently caused by Merkel cell polyomavirus (MCPyV). The median age for MCC diagnosis is 75 years, and MCC is vanishingly rare in patients under 40. We describe 3 patients with X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection, and neoplasia (XMEN) who developed MCC before age 25. XMEN disease is a rare immunodeficiency associated with lymphoma and caused by mutations in the magnesium transporter 1 (MAGT1) gene. Methods: Retrospective chart review for 3 individuals with MCC and XMEN disease. Results: Patient 1 had a history of recurrent childhood infections and splenomegaly and presented at 14 years of age with metastatic MCC that was treated with high-intensity chemotherapy, radiation therapy, and an autologous stem cell transplant. Patient 2 had a history of chronic EBV viremia and recurrent infections and presented at age 22 with Stage III MCC that was treated with surgical resection and radiotherapy. Patient 3 had a history of thrombocytopenia, splenomegaly, and recurrent infections and developed Stage I MCC at age 24 that was treated with surgical resection and radiotherapy. All three patients had MCPyV positive tumors. The patients are alive and tumor-free 13, 4, and 9 years after diagnosis, respectively. Conclusion: Although immunosuppression increases MCC incidence, XMEN disease is associated with a risk for early onset MCC not observed in other primary immunodeficiencies. The MCPyV positivity and prolonged survival in these 3 cases is also atypical for immunosuppressed patients with MCC.

Long non-coding RNA FLVCR1-AS1 functions as a ceRNA to aggravate cervical cancer cell growth by the miR-381-3p/MAGT1 axis.

Cervical cancer (CC), as one of the most widespread gynecological malignancies in the world, severely threatens women health. Long non-coding RNA (lncRNA) could exert vital functions in assorted cancers, including CC. Although FLVCR heme transporter 1 antisense RNA 1 (FLVCR1-AS1) has been recognized as a critical effector in different cancers, its precise role and mechanisms have never been studied in CC. RT-qPCR analysis was done for the measurement of the expression of FLVCR1-AS1, magnesium transporter 1 (MAGT1) and miR-381-3p in CC cells. Supported by western blot analysis, functional assays were done to evaluate the CC cell phenotype, while mechanism assays were done to explore the putative correlation among genes. In CC cells, FLVCR1-AS1 and MAGT1 were upregulated and miR-381-3p was downregulated. FLVCR1-AS1 or MAGT1 knockdown or miR-381-3p augment restrained CC cell proliferation, migration and invasion, but facilitated cell apoptosis. FLVCR1-AS1 sponged miR-381-3p, and MAGT1 was targeted by the FLVCR1-AS1/miR-381-3p axis. It was also revealed that the inhibitory influences of FLVCR1-AS1 silence on CC cell malignant behaviors were countervailed by MAGT1 overexpression. FLVCR1-AS1 exacerbated the malignant phenotype of CC cells via the miR-381-3p/MAGT1 axis.

Oncogenic magnesium transporter 1 upregulates programmed death-1-ligand 1 expression and contributes to growth and radioresistance of glioma cells through the ERK/MAPK signaling pathway

ABSTRACT Radiotherapy has been established as a major therapeutic modality for glioma, whereas new therapeutic targets are needed to prevent tumor recurrence. This study intends to explore the regulatory role of magnesium transporter 1 (MAGT1) in radiotherapy resistance of glioma through modulating ERK and programmed death-1-ligand 1 (PD-L1). Our bioinformatics analysis identified differentially expressed MAGT1 in glioma, expression of which was subsequently determined in cohort data of TCGA database and microarray dataset as well as glioma cell lines. Artificial modulation of MAGT1, ERK, and PD-L1 expression was performed to examine their effects on glioma cell proliferation and radioresistance, as reflected by MTT and colony formation assays under irradiation. Mouse glioma cells with manipulated MAGT1 and ERK inhibitors were further injected into mice to assess the in vivo tumor formation ability of glioma cells. It was noted that MAGT1 expression was highly expressed in glioma tissues of TCGA data and microarray dataset, which was then validated in glioma cell lines. Ectopic expression of MAGT1 was revealed to promote the proliferation and radioresistance of glioma cells, which was attributed to the MAGT1-mediated activation of the ERK/MAPK signaling pathway. It was illuminated that MAGT1 stimulated PD-L1 expression through the ERK/MAPK pathway and thus facilitated glioma cell growth. Additionally, MAGT1 overexpression accelerated the in vivo tumor formation of glioma cells, while the ERK inhibitor negated its effect. In conclusion, MAGT1 enhances the growth and radioresistance of glioma cells through the ERK/MAPK signaling pathway-mediated upregulation of PD-L1 expression.

Scales of Magt1 Gene: Novel Mutations, Different Presentations

Loss-of-function mutations in magnesium transporter 1 (MAGT1) gene cause X-linked magnesium deficiency with Epstein-Barr virus (EBV) infection and neoplasm (X-MEN), a disease with quite diverse clinical and immunological consequences. The phenotypic characteristics of the initially described patients included CD4+ T cell lymphopenia, immune deficiency, EBV viremia, and EBV-related lymphoproliferative disease. To date, a total of 25 patients have been reported. The spectrum of the MAGT1 defect ranges from other viral infections (HSV, VZV, CMV, MCV) and sinopulmonary bacterial infections, autoimmune diseases, non-EBV driven lymphoproliferative disease, Castleman disease, HHV8+ Kaposi's sarcoma, vasculitis (Kawasaki) to glycosylation defects in new patients. Here, we report 2 patients from two different families with novel MAGT1 mutations and different clinical features. The first patient presented with B cell lymphoma and low IgM level without recurrent infections. The second patient presented with recurrent upper respiratory tract infections, Kawasaki-like disease, hypogammaglobulinemia, and T cell lymphopenia. X-MEN disease is the first phenotype identified due to MAGT1 mutation. The identification of new mutations and atypical presentations will clarify whether there is a relationship between the genotype and the phenotype and the characteristics of the disease.

TCF12 activates MAGT1 expression to regulate the malignant progression of pancreatic carcinoma cells.

As a highly malignant gastrointestinal tumor, pancreatic carcinoma (PC) has poor prognosis due to its low early diagnosis rate, advanced tumor resection and chemotherapy resistance. Magnesium transporter 1 (MAGT1) is a magnesium ion transporter located on the cell membrane, which shows promotive effects on biological behaviors of multiple tumor cells. The aim of the present study was to investigate the role of MAGT1 in the progression of PC and its potential molecular mechanism. Based on the Gene Expression Profiling Interactive Analysis website, MAGT1 was highly expressed in tissues from patients with PC and was associated with poor prognosis. In functional experiments, MAGT1 was highly expressed in PC cell lines. The Cell Counting Kit-8, gap closure and Transwell assays, and western blot analysis, were used to investigate the effects of MAGT1 overexpression or knockdown on the biological behaviors of PC cells. It was found that MAGT1 promoted the proliferation, migration and invasion of PC cells in vitro. According to the Encyclopedia of RNA Interactomes website, transcription factor 12 (TCF12) mRNA expression level was positively correlated with MAGT1 expression level in the tissues from patients with PC. Positive targeting regulation of MAGT1 by TCF12 was also confirmed using a dual-luciferase gene reporter assay and chromatin immunoprecipitation. In addition, knockdown of TCF12 expression inhibited the proliferation and migration of PC cells, but overexpression of MAGT1 expression partly reversed this. These results suggested that TCF12 could promote the proliferation, migration and invasion of PC cells by activating MAGT1 expression, which was associated with poor prognosis. These findings suggest that MAGT1 could be a promising biomarker for the occurrence, progression and prognosis of PC.

A Double-Blind, Placebo-Controlled, Crossover Study of Magnesium Supplementation in Patients with XMEN Disease.

X-linked MAGT1 deficiency with increased susceptibility to Epstein-Barr virus (EBV) infection and N-linked glycosylation defect (XMEN) disease is an inborn error of immunity caused by loss-of-function mutations in the magnesium transporter 1 (MAGT1) gene. The original studies of XMEN patients focused on impaired magnesium regulation, leading to decreased EBV-cytotoxicity and the loss of surface expression of the activating receptor "natural killer group 2D" (NKG2D) on CD8+ T cells and NK cells. In vitro studies showed that supraphysiological supplementation of magnesium rescued these defects. Observational studies in 2 patients suggested oral magnesium supplementation could decrease EBV viremia. Hence, we performed a randomized, double-blind, placebo-controlled, crossover study in 2 parts. In part 1, patients received either oral magnesium L-threonate (MLT) or placebo for 12weeks followed by 12weeks of the other treatment. Part 2 began with 3days of high-dose intravenous (IV) magnesium sulfate (MgSO4) followed by open-label MLT for 24weeks. One EBV-infected and 3 EBV-naïve patients completed part 1. One EBV-naïve patient was removed from part 2 of the study due to asymptomatic elevation of liver enzymes during IV MgSO4. No change in EBV or NKG2D status was observed. In vitro magnesium supplementation experiments in cells from 14 XMEN patients failed to significantly rescue NKG2D expression and the clinical trial was stopped. Although small, this study indicates magnesium supplementation is unlikely to be an effective therapeutic option in XMEN disease.

Mg2+ Transporters in Digestive Cancers.

Despite magnesium (Mg2+) representing the second most abundant cation in the cell, its role in cellular physiology and pathology is far from being elucidated. Mg2+ homeostasis is regulated by Mg2+ transporters including Mitochondrial RNA Splicing Protein 2 (MRS2), Transient Receptor Potential Cation Channel Subfamily M, Member 6/7 (TRPM6/7), Magnesium Transporter 1 (MAGT1), Solute Carrier Family 41 Member 1 (SCL41A1), and Cyclin and CBS Domain Divalent Metal Cation Transport Mediator (CNNM) proteins. Recent data show that Mg2+ transporters may regulate several cancer cell hallmarks. In this review, we describe the expression of Mg2+ transporters in digestive cancers, the most common and deadliest malignancies worldwide. Moreover, Mg2+ transporters’ expression, correlation and impact on patient overall and disease-free survival is analyzed using Genotype Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) datasets. Finally, we discuss the role of these Mg2+ transporters in the regulation of cancer cell fates and oncogenic signaling pathways.

Magnesium in Infectious Diseases in Older People.

Reduced magnesium (Mg) intake is a frequent cause of deficiency with age together with reduced absorption, renal wasting, and polypharmacotherapy. Chronic Mg deficiency may result in increased oxidative stress and low-grade inflammation, which may be linked to several age-related diseases, including higher predisposition to infectious diseases. Mg might play a role in the immune response being a cofactor for immunoglobulin synthesis and other processes strictly associated with the function of T and B cells. Mg is necessary for the biosynthesis, transport, and activation of vitamin D, another key factor in the pathogenesis of infectious diseases. The regulation of cytosolic free Mg in immune cells involves Mg transport systems, such as the melastatin-like transient receptor potential 7 channel, the solute carrier family, and the magnesium transporter 1 (MAGT1). The functional importance of Mg transport in immunity was unknown until the description of the primary immunodeficiency XMEN (X-linked immunodeficiency with Mg defect, Epstein–Barr virus infection, and neoplasia) due to a genetic deficiency of MAGT1 characterized by chronic Epstein–Barr virus infection. This and other research reporting associations of Mg deficit with viral and bacterial infections indicate a possible role of Mg deficit in the recent coronavirus disease 2019 (COVID-19) and its complications. In this review, we will discuss the importance of Mg for the immune system and for infectious diseases, including the recent pandemic of COVID-19.

Successful Anti-SARS-CoV-2 Spike Protein Antibody Response to Vaccination in MAGT1 Deficiency.

BackgroundNovel messenger RNA vaccines against severe acute respiratory syndrome coronavirus (SARS-CoV-2) have been vital in resolving the coronavirus disease-2019 (COVID-19) pandemic. Detection of neutralizing antibodies (NAbs) against the SARS-CoV-2 spike protein (S) confirms immunogenicity with high sensitivity and specificity. Few recent studies with primary and secondary immunodeficient cohorts present adequate or reduced antibody response. We describe the first reported successful response to anti-SARS-CoV-2 S antibody post-vaccination in magnesium transporter 1 (MAGT1) gene deficiency, more commonly recognized as x-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia (XMEN).Case PresentationWe present a 30-year-old male with selective anti-polysaccharide antibody deficiency, peripheral blood CD5 + /CD19 + B-cell predominance (97%), MAGT1 mutation, and reduced CD16 + CD56 + natural killer- and/or CD8 + T-cell receptor, Group 2, Member D expression. His initial immunological evaluation revealed all seronegative post-vaccination antibody titers but clinically adequate response to protein antigens tetanus and diphtheria anti-toxoids.COVID-19 vaccination and associated serology antibody testing was recommended at this office visit. Anti-SARS-CoV-2 immunoglobulin (Ig)M and IgG antibodies before and after the first BNT162b2 mRNA COVID-19 vaccine doses, as well as nucleocapsid antibody, were negative. S protein total antibody was reactive after the second dose.DiscussionRobust immunological sequelae post-COVID-19 vaccination in the general population are well-documented in the recent literature. Few studies have evaluated COVID-19 vaccination antibody response in immunodeficient patients. The majority positive anti-S antibody detection in most primary immunodeficient (PID) patients among the few studies in the literature, such as the present case, support the safety and efficacy of mRNA COVID-19 vaccination in immunodeficient patients, although larger scale studies are needed. ConclusionWe demonstrate successful vaccination in the PID MAGT1 deficiency in this first reported case of reactive anti-S antibody post-COVID-19 vaccination.

MAGT1 messenger RNA-corrected autologous T and natural killer cells for potential cell therapy in X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia disease

Background aimX-linked MAGT1 deficiency with increased susceptibility to EBV-infection and N-linked glycosylation defect' (XMEN) disease is caused by mutations in the magnesium transporter 1 (MAGT1) gene. Loss of MAGT1 function results in a glycosylation defect that abrogates expression of key immune proteins such as the NKG2D receptor on CD8+ T and NK cells, which is critical for the recognition and killing of virus-infected and transformed cells, a biomarker for MAGT1 function. Patients with XMEN disease frequently have increased susceptibility to EBV infections and EBV-associated B cell malignancies, for which no specific treatment options are currently available. Experimental transfer of donor EBV-specific cytotoxic T cells may be beneficial but carries the risks of eliciting alloimmune responses. An approach for cell therapy to address viral infections and associated complications that avoids the risks of alloimmunity is needed. MethodsHere the authors assess the feasibility and efficiency of correcting autologous lymphocytes from XMEN patients by MAGT1 mRNA electroporation (EP) that avoids genomic integration and can be scaled for clinical application. Results and conclusionsRestoration of NKG2D expression was demonstrated in XMEN patient lymphocytes after MAGT1 mRNA electroporation that reach healthy donor levels in CD8+ T and NK cells at 1-2 days after EP. NKG2D expression persisted at ∼50% for 2 weeks after EP. Functionally, mRNA-correction of XMEN NK cells rescued cytotoxic activity also to healthy donor NK cell level. The restored NKG2D receptor expression and function were unaffected by cryopreservation, which will make feasible repeat infusions of MAGT1 mRNA-corrected autologous XMEN CD8+ T and NK cells for potential short term therapy for XMEN patients without the risks of alloimmunization.

MiR-199a-5p targeted regulation of MAGT1 expression in the functional depletion of CD8+T cells in HBV infection.

Magnesium transporter 1 (MAGT1) is a key protein that regulates the level of free Mg2+ in cells. Previous studies found that the downregulation of MAGT1 expression in CD8+T cells of HBV patients was correlated with the decrease of intracellular magnesium. However, the expression of MAGT1 mRNA in the CD8+T cells from HBV patients was not significantly altered, indicating that the change in MAGT1 expression was accomplished through posttranscriptional regulation. Through bioinformatics and qRT-PCR detection, miR-199a-5p was found to have a target gene relationship with MAGT1. The expression levels of miR-199a-5p and MAGT1 in HBV infection were evaluated. Lentivirus assays were used to analyze the effects of miR-199a-5p upregulation and downregulation on the MAGT1 expression level and the immune system. Results showed no significant change in the expression of MAGT1 mRNA in HBV-infected cell lines, but the expression of MAGT1 was downregulated. Additionally, the expression level of miR-199a-5p was significantly increased. To this end, we predicted a target relationship between miR-199a-5p and MAGT1 by using TargetScan and verified this relationship through a luciferase activity reporter gene assay. As a result, MAGT1 was found to be the direct target of miR-199a-5p. The targeted inhibition of MAGT1 induced by miR-199a-5p overexpression led to the immune function depletion of CD8+T cells in HBV patients. Downregulating the expression level of miR-199a-5p could effectively improve the functional depletion of CD8+T cells. These findings indicate that miR-199a-5p and MAGT1 could potentially be used as biomarkers for the diagnosis and treatment of chronic HBV infection.

Sevoflurane Regulates Glioma Progression by Circ_0002755/miR-628-5p/MAGT1 Axis.

BackgroundGlioma is a common malignant tumor worldwide. Sevoflurane (Sev) has been reported to inhibit the metastasis of glioma cells, but the underlying molecular mechanism needs further exploration.MethodsCell Counting Kit-8 (CCK8) assay was used to check cell viability. Flow cytometry assay was hired to check cell apoptosis. The protein levels of B-cell lymphoma-2 (Bcl-2), BCL2-Associated X (Bax), hexokinase 2 (HK2) and magnesium transporter 1 (MAGT1) in samples were measured by Western blot. The abilities of cell migration and invasion were estimated by transwell assay. Glucose colorimetric assay kit and lactate colorimetric assay kit were used to check glucose consumption and lactate production, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the levels of circular RNA (circRNA) circ_0002755 (also known as the circRNA1656) and microRNA (miR)-628-5p in samples. The interaction between miR-628-5p and circ_0002755 or MAGT1 was predicated by starBase, which was verified by the dual-luciferase reporter assay. Xenograft tumor model was established to explore the biological role of circ_0002755 in vivo.ResultsSev inhibited cell viability, migration, invasion and promoted cell apoptosis, and also reduced glucose consumption and lactate production. Circ_0002755 was significantly upregulated in glioma tissues and cells, while its level was notably declined under Sev treatment. Besides, overexpression of circ_0002755 overturned Sev-mediated inhibitory effect on glioma progression. Further research indicated that circ_0002755 targeted miR-628-5p, and miR-628-5p targeted MAGT1, and Sev modulated glioma progression via circ_0002755/miR-628-5p/MAGT1 axis. Moreover, Sev hindered tumor growth in vivo.ConclusionSev mediated glioma progression via circ_0002755/miR-628-5p/MAGT1 axis.