Proton-Pump Inhibitors Suppress T Cell Response by Shifting Intracellular Zinc Distribution

In human CD4+ T-Cells, omeprazole suppresses proliferation, downregulates V-ATPase, and promotes differentiation toward an autoimmunity-favoring phenotype

BACKGROUND

Proton pump inhibitors (PPIs) represent a commonly prescribed class of medications. Triggered by findings indicating a correlation between PPI usage and susceptibility to infectious or autoimmune diseases, we studied the impact of a pharmacological concentration of omeprazole on human CD4+ T-cells.

METHODS

In mixed lymphocyte reactions (MLRs), we analyzed the proliferation index and measured the concentration of key cytokines representative of distinct CD4+ T-cell subsets. In CD4+ T-cells isolated from the MLRs, we evaluated proliferation markers and pathways, the expression of signature transcription factors of CD4+ T-cell subsets, vacuolar H+- ATPase (V-ATPase) levels, and the activation status of AMP-activated kinase (AMPK) and mammalian target of rapamycin complex-1 (mTORC1).

RESULTS

Omeprazole reduced proliferation index in MLRs, and in isolated CD4+ T-cells, it downregulated the proliferation marker Ki-67, possibly mediated by the p53- p21 pathway. Analysis of cytokines and signature transcription factors of CD4+ T-cell subsets indicated that omeprazole decreased T helper 1 (Th1) differentiation, had negligible impact on Th2 differentiation, increased Th17 differentiation, and reduced regulatory T-cell (Treg) differentiation. Omeprazole also decreased V-ATPase, a known target of PPIs and a site for AMPK and mTORC1 activation. Consequently, this led to diminished activation of these kinases, potentially elucidating the mechanism by which omeprazole influences CD4+ T-cell differentiation.

CONCLUSION

Omeprazole downregulates V-ATPase and inhibits activation of AMPK and mTORC1. As a result, omeprazole suppresses CD4+ T-cell clonal expansion, potentially contributing to the observed association between PPIs and susceptibility to infections. Additionally, it modulates CD4+ T-cell differentiation in a manner that favors autoimmunity.

Zinc Deficiency Exacerbates Lead-Induced Interleukin-2 Suppression by Regulating CREM Expression

Lead, a prevalent heavy metal, impairs the immune system by affecting T cell function. Similarly, zinc deficiency adversely affects T cells, with zinc deficiency and lead exposure being linked to reduced interleukin-2 (IL-2) production. Zinc deficiency has been associated with increased expression of the transcription factor CREM 100 kDa, which downregulates IL-2. Previous research suggests zinc may mitigate lead's toxic effects. This study explored the molecular mechanism underlying IL-2 reduction in lead-exposed T cells and examined the role of zinc status. The effects of lead exposure were investigated in Jurkat T cells in zinc-adequate, zinc-deficient, and zinc-supplemented conditions. Results showed that lead exposure increased CREM 100 kDa expression, which was amplified under zinc-deficient conditions. Consequently, IL-2 production was significantly lower in cells exposed to both lead and zinc deficiency compared to lead exposure alone. However, zinc supplementation counteracted these effects, preventing CREM 100 kDa overexpression and restoring IL-2 levels. In conclusion, we identified CREM 100 kDa as a potential molecular mechanism behind the lead-induced IL-2 decrease in Jurkat T cells, with zinc deficiency exacerbating this effect. These findings highlight the protective role of zinc in counteracting lead toxicity and emphasize the importance of maintaining adequate zinc levels for immune health.

Treatment with proton pump inhibitors is associated with secondary bacterial infections and sepsis in patients with COVID-19: a retrospective analysis of their joint impact on in-hospital prognosis

Introduction and objectives. Secondary bacterial infections (SBIs) contribute to worse in-hospital outcomes in patients with Coronavirus disease 2019 (COVID-19). Treatment with proton pump inhibitors (PPIs) is associated with an increased risk of bacterial infections in different clinical settings. However, the association between PPI treatment prior to hospital admission and the occurrence of either SBIs or secondary bacterial sepsis (SBS) as well as their joint impact on clinical outcomes of patients hospitalized for COVID-19 are not clarified.

Patients and methods. We retrospectively analyzed preadmission PPI use, in-hospital occurrence of SBIs and SBS, and in-hospital outcomes of a cohort of patients hospitalized for COVID-19.

Results. Among 1087 patients, 447 (41%) were on PPI treatment prior to hospital admission. During the hospital stay, 197 (18%) and 223 (20%) patients were diagnosed with SBIs and SBS, respectively. The composite endpoint of intensive care unit (ICU) admission/in-hospital death was met by 214 (20%) patients. Preadmission PPI treatment was independently associated with up to a 2.1-fold and 1.7-fold increased risk of SBIs and SBS, respectively. The occurrence of SBS was independently associated with up to a 2.2-fold increased risk of ICU admission/in-hospital death. A significant preadmission PPI treatment x SBS interaction emerged in predicting ICU admission/in-hospital death (F = 5.221, pinteraction = 0.023).

Conclusions. PPI treatment prior to hospital admission for COVID-19 is associated with an increased risk of SBIs and SBS. In addition, it interacts with SBS in predicting in-hospital prognosis. An appropriate use of PPIs may attenuate the risk of adverse clinical outcomes during hospitalization for COVID-19.

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.

Ca2+ signals are essential for T-cell proliferation, while Zn2+ signals are necessary for T helper cell 1 differentiation

The regulation of T-cell fate is crucial for the balance between infection control and tolerance. Calcium (Ca2+) and zinc (Zn2+) signals are both induced after T-cell stimulation, but their specific roles in the fate of activation and differentiation remain to be elucidated. Are Zn2+- and Ca2+ signals responsible for different aspects in T-cell activation and differentiation and do they act in concert or in opposition? It is crucial to understand the interplay of the intracellular signals to influence the fate of T cells in diseases with undesirable T-cell activities or in Zn2+-deficient patients. Human peripheral blood mononuclear cells were stimulated with the Zn2+ ionophore pyrithione and thapsigargin, an inhibitor of the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA). Intracellular Zn2+ and Ca2+ signals were monitored by flow cytometry and ELISA, quantitative PCR and western blot were used to evaluate T-cell differentiation and the underlying molecular mechanism. We found that Zn2+ signals upregulated the early T-cell activation marker CD69, interferon regulatory factor 1 (IRF-1), and Krüppel-like factor 10 (KLF-10) expression, which are important for T helper cell (Th) 1 differentiation. Ca2+ signals, on the other hand, increased T-bet and Forkhead box P3 (FoxP3) expression and interleukin (IL)-2 release. Most interestingly, the combination of Zn2+ and Ca2+ signals was indispensable to induce interferon (IFN)-γ expression and increased the surface expression of CD69 by several-fold. These results highlight the importance of the parallel occurrence of Ca2+ and Zn2+ signals. Both signals act in concert and are required for the differentiation into Th1 cells, for the stabilization of regulatory T cells, and induces T-cell activation by several-fold. This provides further insight into the impaired immune functions of patients with zinc deficiency.

Proton pump inhibitors and risk of severe COVID-19 in older people

INTRODUCTION

Severe acute respiratory syndrome coronavirus 2 is a viral respiratory infection that can cause systemic disorders and lead to death, particularly in older people. Proton pump inhibitors (PPIs) increase the risk of enteric and lung infections. Considering the broad use of PPIs in older people, the potential role of PPIs in COVID-19 could be of dramatic significance. The objective of our study was to evaluate the link between PPIs and severe COVID-19 in older people.

METHOD

We performed a retrospective cohort study, including all patients aged ≥65, hospitalised for a diagnosis of COVID-19. Epidemiological, clinical and biological data were extracted and we performed an Inverse Probability of Treatment Weighing method based on a propensity score.

RESULTS

From March 2020 to February 2021, a total of 834 patients were included, with a median age of 83 and 52.8% were male. A total of 410 patients had a PPIs prescription, 358 (87.3%) were long-term PPIs-users and 52 (12.7%) were recent PPIs-users. Among PPIs-users, 163 (39.8%) patients developed severe COVID-19 versus 113 (26.7%) in PPIs-non users (odds ratio (OR) = 1.59 [1.18-2.14]; P < 0.05). Moreover, the double dose PPI-users had a higher risk of developing severe COVID-19 (OR = 3.36 [1.17-9.66]; P < 0.05) than the full dose PPI-users (OR = 2.15 [1.22-3.76]; P < 0.05) and the half dose PPI-users (OR = 1.64 [1.13-2.37]; P < 0.05).

CONCLUSION

Our study reports evidence that the use of PPIs was associated with an increased risk of severe COVID-19 in older people.

Gastric acid-responsive deformable sodium alginate/Bletilla striata polysaccharide in situ gel for the protection and treatment of alcohol-induced peptic ulcers

First-line drugs for peptic ulcer (PU) treatment are typically limited by poor targeting and adverse effects associated with long-term use. Despite recent advancements in novel therapeutic approaches for PU, the development of sustained-release delivery systems tailored to specific pathological characteristics remains challenging. Persistent inflammation, particularly gastric inflammatory microenvironment imbalance, characterizes the PU. In this study, we prepared an in situ gel composed of sodium alginate, deacetylated gellan gum, calcium citrate, and Bletilla striata polysaccharide (BSP) to achieve sustained release of BSP. The BSP in situ gel demonstrated favorable fluidity in vitro and completed self-assembly in vivo in response to the acidic milieu at a pH of 1.5. Furthermore, the shear, extrusion, and deformation properties increased by 26.4 %, 103.7 %, and 46.3 %, respectively, with long-term gastric retention (4 h) and mucosal adaptation. Animal experiments confirmed that the BSP in situ gel could attenuate necrotic injury and inflammatory cell infiltration, maintain mucosal barrier integrity, regulate cytokine imbalance and inflammation-associated hyperapoptosis, thus effectively alleviate the inflammatory microenvironmental imbalance in PU without significant side effects. Overall, our findings demonstrated that the BSP in situ gel is a promising therapeutic strategy for PU and opens avenues for developing self-assembled formulations targeting the pathological features of PUs.

A zinc metabolism-related gene signature for predicting prognosis and characteristics of breast cancer

Background

Breast cancer is one of the most serious and prevalent malignancies. Zinc is commonly known to play a crucial role in the development and progression of breast cancer; however, the detailed mechanisms underlying this role are not well understood. This study aimed to develop a zinc metabolism-related gene (ZMRG) signature based on a multi-database study to predict patient prognosis and investigate the relationship between drug therapy response and immune enrichment.

Methods

Data for breast cancer samples from The Cancer Genome Atlas and Gene Expression Omnibus databases were screened for zinc metabolism-related genes using the Molecular Signature Database. Cox and Least Absolute Shrinkage and Selection Operator regressions were performed to construct a ZMRG signature. To assess the predictive performance of the gene signature, Kaplan-Meier analysis and receiver operating characteristic curves were used. Additionally, we utilised single-sample gene set enrichment analysis, the Tumour Immune Estimation Resource, the Genomics of Drug Sensitivity in Cancer database, and the Cancer Therapeutics Response Portal to investigate the association between the tumour microenvironment and drug sensitivity. Quantitative PCR was used to assess the expression of each gene in the signature in breast cancer cell lines and patient samples.

Results

Five ZMRGs were identified (ATP7B, BGLAP, P2RX4, SLC39A11, and TH) and a risk profile was constructed for each. Two risk groups, high- and low-risk, were identified in this way, and the high-risk score subgroups were found to have worse prognosis. This risk profile was validated using the GSE42568 dataset. Tumour microenvironment and drug sensitivity analyses showed that the expression of these five ZMRGs was significantly associated with immune response. The high-risk group showed substantial immune cell infiltration and enrichment of immune pathways, and patients were more sensitive to drugs commonly used in breast cancer.

Conclusion

The ZMRG signature represents a new prognostic predictor for patients with breast cancer, and may also provide new insights into individualised treatment of breast cancer.