Control of CD4+ T cells to restrain inflammatory diseases via eukaryotic elongation factor 2 kinase.

CD4+ T cells, particularly IL-17-secreting helper CD4+ T cells, play a central role in the inflammatory processes underlying autoimmune disorders. Eukaryotic Elongation Factor 2 Kinase (eEF2K) is pivotal in CD8+ T cells and has important implications in vascular dysfunction and inflammation-related diseases such as hypertension. However, its specific immunological role in CD4+ T cell activities and related inflammatory diseases remains elusive. Our investigation has uncovered that the deficiency of eEF2K disrupts the survival and proliferation of CD4+ T cells, impairs their ability to secrete cytokines. Notably, this dysregulation leads to heightened production of pro-inflammatory cytokine IL-17, fosters a pro-inflammatory microenvironment in the absence of eEF2K in CD4+ T cells. Furthermore, the absence of eEF2K in CD4+ T cells is linked to increased metabolic activity and mitochondrial bioenergetics. We have shown that eEF2K regulates mitochondrial function and CD4+ T cell activity through the upregulation of the transcription factor, signal transducer and activator of transcription 3 (STAT3). Crucially, the deficiency of eEF2K exacerbates the severity of inflammation-related diseases, including rheumatoid arthritis, multiple sclerosis, and ulcerative colitis. Strikingly, the use of C188-9, a small molecule targeting STAT3, mitigates colitis in a murine immunodeficiency model receiving eEF2K knockout (KO) CD4+ T cells. These findings emphasize the pivotal role of eEF2K in controlling the function and metabolism of CD4+ T cells and its indispensable involvement in inflammation-related diseases. Manipulating eEF2K represents a promising avenue for novel therapeutic approaches in the treatment of inflammation-related disorders.

Engineering live attenuated vaccines: Old dogs learning new tricks.

Autoimmune diseases such as rheumatoid arthritis and type 1 diabetes are increasingly common global problems. Concerns about increases in the prevalence of such diseases and the limited efficacy of conventional treatment regimens necessitates new therapies to address these challenges. Autoimmune disease severity and dysbiosis are interconnected. Although probiotics have been established as a therapy to rebalance the microbiome and suppress autoimmune symptoms, these microbes tend to lack a number of advantageous qualities found in non-commensal bacteria. Through attenuation and genetic manipulation, these non-commensal bacteria have been engineered into recombinant forms that offer malleable platforms capable of addressing the immune imbalances found in RA and T1D. Such bacteria have been engineered to express valuable gene products known to suppress autoimmunity such as anti-inflammatory cytokines, autoantigens, and enzymes synthesizing microbial metabolites. This review will highlight current and emerging trends in the field and discuss how they may be used to prevent and control autoimmune diseases.

T Cell Response to SARS-CoV-2 Coinfection and Comorbidities.

For the past three years, COVID-19 has become an increasing global health issue. Adaptive immune cells, especially T cells, have been extensively investigated in regard to SARS-CoV-2 infection. However, human health and T cell responses are also impacted by many other pathogens and chronic diseases. We have summarized T cell performance during SARS-CoV-2 coinfection with other viruses, bacteria, and parasites. Furthermore, we distinguished if those altered T cell statuses under coinfection would affect their clinical outcomes, such as symptom severity and hospitalization demand. T cell alteration in diabetes, asthma, and hypertension patients with SARS-CoV-2 infection was also investigated in our study. We have summarized whether changes in T cell response influence the clinical outcome during comorbidities.

A metabolically engineered bacterium controls autoimmunity and inflammation by remodeling the pro-inflammatory microenvironment.

Immunotherapy has led to impressive advances in the treatment of autoimmune and pro-inflammatory disorders; yet, its clinical outcomes remain limited by a variety of factors including the pro-inflammatory microenvironment (IME). Discovering effective immunomodulatory agents, and the mechanisms by which they control disease, will lead to innovative strategies for enhancing the effectiveness of current immunotherapeutic approaches. We have metabolically engineered an attenuated bacterial strain (i.e., Brucella melitensis 16M ∆vjbR, Bm∆vjbR::tnaA) to produce indole, a tryptophan metabolite that controls the fate and function of regulatory T (Treg) cells. We demonstrated that treatment with Bm∆vjbR::tnaA polarized macrophages (Mφ) which produced anti-inflammatory cytokines (e.g., IL-10) and promoted Treg function; moreover, when combined with adoptive cell transfer (ACT) of Treg cells, a single treatment with our engineered bacterial strain dramatically reduced the incidence and score of autoimmune arthritis and decreased joint damage. These findings show how a metabolically engineered bacterium can constitute a powerful vehicle for improving the efficacy of immunotherapy, defeating autoimmunity, and reducing inflammation by remodeling the IME and augmenting Treg cell function.

Expression of NAC1 Restrains the Memory Formation of CD8+ T Cells during Viral Infection.

Nucleus accumbens-associated protein 1 (NAC1) is a transcription co-factor that has been shown to possess multiple roles in stem cell and cancer biology. However, little is known about its roles in regulation of the immune system. In the current study, we observed that expression of NAC1 impacted the survival of CD8+ T cells in vitro. NAC1-/- CD8+ T cells displayed lower metabolism, including reduced glycolysis and oxidative phosphorylation. In vivo, compared with wild-type (WT) mice, NAC1-/- mice produced a lower response to vaccinia virus (VACV) infection, and viral antigen (Ag)-specific CD8+ T cells decreased more slowly. Additionally, we observed that the NAC1-/- mice demonstrated a stronger memory formation of viral Ag-specific CD8+ T cells post-viral infection. Mechanically, we identified that compared with WT CD8+ T cells, the Interferon Regulatory Factor 4 (IRF4), a key transcription factor in T cell development, was highly expressed in NAC1-/- CD8+ T cells, insinuating that IRF4 could be a critical regulatory target of NAC1 in the memory formation of CD8+ T cells. Our results indicate that NAC1 restrains the memory formation of CD8+ T cells by modulating IRF4, and targeting NAC1 may be exploited as a new approach to boosting CD8+ T cell memory.

NAC1 modulates autoimmunity by suppressing regulatory T cell-mediated tolerance.

We report here that nucleus accumbens-associated protein-1 (NAC1), a nuclear factor of the Broad-complex, Tramtrack, Bric-a-brac/poxvirus and zinc finger (BTB/POZ) gene family, is a negative regulator of FoxP3 in regulatory T cells (Tregs) and a critical determinant of immune tolerance. Phenotypically, NAC1-/- mice showed substantial tolerance to the induction of autoimmunity and generated a larger amount of CD4+ Tregs that exhibit a higher metabolic profile and immune-suppressive activity, increased acetylation and expression of FoxP3, and slower turnover of this transcription factor. Treatment of Tregs with the proinflammatory cytokines interleukin-1ß or tumor necrosis factor-α induced a robust up-regulation of NAC1 but evident down-regulation of FoxP3 as well as the acetylated FoxP3. These findings imply that NAC1 acts as a trigger of the immune response through destabilization of Tregs and suppression of tolerance induction, and targeting of NAC1 warrants further exploration as a potential tolerogenic strategy for treatment of autoimmune disorders.

Elongation factor-2 kinase is a critical determinant of the fate and antitumor immunity of CD8+ T cells.

eEF-2K has important roles in stress responses and cellular metabolism. We report here a previously unappreciated but critical role of eEF-2K in regulating the fate and cytocidal activity of CD8+ T cells. CD8+ T cells from eEF-2K KO mice were more proliferative but had lower survival than their wild-type counterparts after their activation, followed by occurrence of premature senescence and exhaustion. eEF-2K KO CD8+ T cells were more metabolically active and showed hyperactivation of the Akt-mTOR-S6K pathway. Loss of eEF-2K substantially impaired the activity of CD8+ T cells. Furthermore, the antitumor efficacy and tumor infiltration of the CAR-CD8+ T cells lacking eEF-2K were notably reduced as compared to the control CAR-CD8+ T cells. Thus, eEF-2K is critically required for sustaining the viability and function of cytotoxic CD8+ T cells, and therapeutic augmentation of this kinase may be exploited as a novel approach to reinforcing CAR-T therapy against cancer.

Insights Into the Pathologic Roles and Regulation of Eukaryotic Elongation Factor-2 Kinase.

Eukaryotic Elongation Factor-2 Kinase (eEF2K) acts as a negative regulator of protein synthesis, translation, and cell growth. As a structurally unique member of the alpha-kinase family, eEF2K is essential to cell survival under stressful conditions, as it contributes to both cell viability and proliferation. Known as the modulator of the global rate of protein translation, eEF2K inhibits eEF2 (eukaryotic Elongation Factor 2) and decreases translation elongation when active. eEF2K is regulated by various mechanisms, including phosphorylation through residues and autophosphorylation. Specifically, this protein kinase is downregulated through the phosphorylation of multiple sites via mTOR signaling and upregulated via the AMPK pathway. eEF2K plays important roles in numerous biological systems, including neurology, cardiology, myology, and immunology. This review provides further insights into the current roles of eEF2K and its potential to be explored as a therapeutic target for drug development.

Metabolic Reprogramming and Reactive Oxygen Species in T Cell Immunity.

T cells undergo metabolic reprogramming and multiple biological processes to satisfy their energetic and biosynthetic demands throughout their lifespan. Several of these metabolic pathways result in the generation of reactive oxygen species (ROS). The imbalance between ROS generation and scavenging could result in severe damage to the cells and potential cell death, ultimately leading to T cell-related diseases. Interestingly, ROS play an essential role in T cell immunity. Here, we introduce the important connectivity between T cell lifespan and the metabolic reprogramming among distinct T cell subsets. We also discuss the generation and sources of ROS production within T cell immunity as well as highlight recent research concerning the effects of ROS on T cell activities.

Stem Cell-Derived Viral Antigen-Specific T Cells Suppress HIV Replication and PD-1 Expression on CD4+ T Cells.

The viral antigen (Ag)-specific CD8+ cytotoxic T lymphocytes (CTLs) derived from pluripotent stem cells (PSCs), i.e., PSC-CTLs, have the ability to suppress the human immunodeficiency virus (HIV) infection. After adoptive transfer, PSC-CTLs can infiltrate into the local tissues to suppress HIV replication. Nevertheless, the mechanisms by which the viral Ag-specific PSC-CTLs elicit the antiviral response remain to be fully elucidated. In this study, we generated the functional HIV-1 Gag epitope SL9-specific CTLs from the induced PSC (iPSCs), i.e., iPSC-CTLs, and investigated the suppression of SL9-specific iPSC-CTLs on viral replication and the protection of CD4+ T cells. A chimeric HIV-1, i.e., EcoHIV, was used to produce HIV replication in mice. We show that adoptive transfer of SL9-specific iPSC-CTLs greatly suppressed EcoHIV replication in the peritoneal macrophages and spleen in the animal model. Furthermore, we demonstrate that the adoptive transfer significantly reduced expression of PD-1 on CD4+ T cells in the spleen and generated persistent anti-HIV memory T cells. These results indicate that stem cell-derived viral Ag-specific CTLs can robustly accumulate in the local tissues to suppress HIV replication and prevent CD4+ T cell exhaustion through reduction of PD-1 expression.

An optimized protocol for the generation of HBV viral antigen-specific T lymphocytes from pluripotent stem cells.

In T cell-based cancer immunotherapy, tumor antigen (Ag)-specific CD8+ cytotoxic T lymphocytes (CTLs) can specifically target tumor Ags on malignant cells. This promising approach drove us to adopt this strategy of T cell transfer (ACT)-based immunotherapy for chronic viral infections. Here, we describe the generation of hepatitis B virus (HBV) Ag-specific CTLs from induced pluripotent stem cells (iPSCs), i.e., iPSC-CTLs. Ag-specific iPSC-CTLs can target HBV Ag+ cells and infiltrate into the liver to suppress HBV replication in a murine model. For complete details on the use and execution of this protocol, please refer to Haque et al. (2020).

Autophagy in T-cell differentiation, survival and memory.

Over the past decade, autophagy has emerged as a critical regulatory mechanism of the immune system through critically controlling various aspects of T cell biology and determining the fate of different T cell subsets. Autophagy maintains T cell development and survival by regulating the degradation of organelles and apoptotic proteins. The autophagic process also impacts the formation of memory T cells. Alteration of autophagy in T cells may lead to a variety of pathological conditions such as inflammation, autoimmune diseases and cancer. In this review, we discuss how autophagy impacts T cell differentiation, survival and memory, and its implication in immunotherapy for various diseases.

Stem Cell-Derived Viral Antigen-Specific T Cells Suppress HBV Replication through Production of IFN-γ and TNF-⍺.

The viral antigen (Ag)-specific CD8+ cytotoxic T lymphocytes (CTLs) derived from pluripotent stem cells (PSCs), i.e., PSC-CTLs, have the ability to suppress hepatitis B virus (HBV) infection. After adoptive transfer, PSC-CTLs can infiltrate into the liver to suppress HBV replication. Nevertheless, the mechanisms by which the viral Ag-specific PSC-CTLs provoke the antiviral response remain to be fully elucidated. In this study, we generated the functional HBV surface Ag-specific CTLs from the induced PSC (iPSCs), i.e., iPSC-CTLs, and investigated the underlying mechanisms of the CTL-mediated antiviral replication in a murine model. We show that adoptive transfer of HBV surface Ag-specific iPSC-CTLs greatly suppressed HBV replication and prevented HBV surface Ag expression. We further demonstrate that the adoptive transfer significantly increased T cell accumulation and production of antiviral cytokines. These results indicate that stem cell-derived viral Ag-specific CTLs can robustly accumulate in the liver and suppress HBV replication through producing antiviral cytokines.

Development of CAR-T Cell Persistence in Adoptive Immunotherapy of Solid Tumors.

Chimeric antigen receptor (CAR) T (CAR-T) cell transfer has made great success in hematological malignancies, but only shown a limited effect on solid tumors. One of the major hurdles is the poor persistence of infused cells derived from ex vivo activation/expansion and repeated antigen encounter after re-infusion. Bcl-xL has been demonstrated to play an important role on normal T cell survival and function as well as genetically engineered cells. In the current study, we developed a retroviral CAR construct containing a second-generation carcinoembryonic antigen (CEA)-targeting CAR with the Bcl-xL gene and tested the anti-CEA CAR-T cell immunotherapy for colorectal cancer. In vitro, the anti-CEA CAR-T cells destroyed CEA-expressing tumor cells and sustained survival. In vivo, adoptive cell transfer of anti-CEA CAR-T cells significantly enhanced the ability of the CAR-T cells to accumulate in tumor tissues, suppress tumor growth and increase the overall survival rate of tumor-bearing mice in a murine model of colorectal cancer. These results demonstrate a novel CAR-T platform that has the ability to increase the persistence of CAR-T cells in solid tumors through exogenous expression of persistent genes. The data provide a potentially novel approach to augment CAR-T immunotherapy for solid tumors.

Heat Shock Proteins in Cancer Immunotherapy.

Heat shock proteins (HSPs) are highly conserved molecular chaperones with divergent roles in various cellular processes. The HSPs are classified according to their molecular size as HSP27, HSP40, HSP60, HSP70, and HSP90. The HSPs prevent nonspecific cellular aggregation of proteins by maintaining their native folding energetics. The disruption of this vital cellular process, driven by the aberrant expression of HSPs, is implicated in the progression of several different carcinomas. Many HSPs are also actively involved in promoting the proliferation and differentiation of tumor cells, contributing to their metastatic phenotype. Upregulation of these HSPs is associated with the poor outcome of anticancer therapy in clinical settings. On the other hand, these highly expressed HSPs may be exploited as viable immunotherapeutic targets for different types of cancers. This review discusses recent advances and perspectives on the research of HSP-based cancer immunotherapy.

Targeting Stem Cell-Derived Tissue-Associated Regulatory T Cells for Type 1 Diabetes Immunotherapy.

PURPOSE OF REVIEW: Type 1 diabetes (T1D) is an autoimmune disease in which the immune cells selectively destroy the pancreatic beta (ß) cells and results in the deficiency of insulin production. The optimal treatment strategy for T1D should be preventing of ß-cell destruction in the pancreas. The purpose of this review is to discuss the immunological therapeutic mechanisms that will help to understand the development and control of ß-cell destruction. The review also presents a novel method for development of autoantigen (Ag)-specific regulatory T cells (Tregs) for T1D immunotherapy. RECENT FINDINGS: Pancreatic-resident Tregs have the ability to dramatically suppress hyperactive immune cells. Islet cell transplantation is another attractive approach to replace the failed ß cells. Due to the limited source of islet cells, research is going on in the use of animal cells and adult stem cells that may be derived from the patient's own body to produce ß cells for transplantation. The mechanism behind the pancreatic ß-cell destruction is largely unknown. In this review, a novel approach for the generation of tissue-associated Tregs from stem cells is considered. The stem cell-derived tissue-associated Tregs have the ability to home to the damaged pancreas to prevent the destruction. The review also provides new insights on the mechanism on how these suppressive immune cells protect the pancreas from the destruction of autoimmune cells. A novel method to develop functional auto Ag-specific Tregs that are derived from induced pluripotent stem cells (iPSCs), i.e., iPSC-Tregs, is discussed. Adoptive transfer of the iPSC-Tregs can substantially suppress T1D development in a murine model.

Stem cell-derived tissue-associated regulatory T cells suppress the activity of pathogenic cells in autoimmune diabetes.

The autoantigen-specific Tregs from pluripotent stem cells (PSCs), i.e., PSC-Tregs, have the ability to suppress autoimmunity. PSC-Tregs can be programmed to be tissue associated and to infiltrate into local inflamed tissues to suppress autoimmune responses after adoptive transfer. Nevertheless, the mechanisms by which the autoantigen-specific PSC-Tregs suppress the autoimmune response remain to be fully elucidated. In this study, we generated functional autoantigen-specific Tregs from the induced PSC (iPSCs), i.e., iPSC-Tregs, and investigated the underlying mechanisms of autoimmunity suppression by these Tregs in a type 1 diabetes (T1D) murine model. A double-Tg mouse model of T1D was established in F1 mice, in which the first generation of RIP-mOVA Tg mice that were crossed with OT-I T cell receptor (TCR) Tg mice was challenged with vaccinia viruses expressing OVA (VACV-OVA). We show that adoptive transfer of OVA-specific iPSC-Tregs greatly suppressed autoimmunity in the animal model and prevented the insulin-secreting pancreatic ß cells from destruction. Further, we demonstrate that the adoptive transfer significantly reduced the expression of ICAM-1 in the diabetic pancreas and inhibited the migration of pathogenic CD8+ T cells and the production of the proinflammatory IFN-γ in the pancreas. These results indicate that the stem cell-derived tissue-associated Tregs can robustly accumulate in the diabetic pancreas, and, through downregulating the expression of ICAM-1 in the local inflamed tissues and inhibiting the production of proinflammatory cytokine IFN-γ, suppress the migration and activity of the pathogenic immune cells that cause T1D.

Janus kinase 3 regulates adherens junctions and epithelial mesenchymal transition through ß-catenin.

Compromise in adherens junctions (AJs) is associated with several chronic inflammatory diseases. We reported previously that Janus kinase 3, a non-receptor tyrosine kinase, plays a crucial role in AJ formation through its interaction with ß-catenin. In this report, we characterize the structural determinants responsible for Jak3 interactions with ß-catenin and determine the functional implications of previously unknown tyrosine residues on ß-catenin phosphorylated by Jak3. We demonstrate that Jak3 autophosphorylation was the rate-limiting step during Jak3 trans-phosphorylation of ß-catenin, where Jak3 directly phosphorylated three tyrosine residues, viz. Tyr30, Tyr64, and Tyr86 in the N-terminal domain (NTD) of ß-catenin. However, prior phosphorylation of ß-catenin at Tyr654 was essential for further phosphorylation of ß-catenin by Jak3. Interaction studies indicated that phosphorylated Jak3 bound to phosphorylated ß-catenin with a dissociation constant of 0.28 µm, and although both the kinase and FERM (Band 41, ezrin, radixin, and moesin) domains of Jak3 interacted with ß-catenin, the NTD domain of ß-catenin facilitated its interactions with Jak3. Physiologically, Jak3-mediated phosphorylation of ß-catenin suppressed EGF-mediated epithelial-mesenchymal transition and facilitated epithelial barrier functions by AJ localization of phosphorylated ß-catenin through its interactions with α-catenin. Moreover, loss of Jak3-mediated phosphorylation sites in ß-catenin abrogated its AJ localization and compromised epithelial barrier functions. Thus, we not only characterize Jak3 interaction with ß-catenin but also demonstrate the mechanism of molecular interplay between AJ dynamics and EMT by Jak3-mediated NTD phosphorylation of ß-catenin.

Natural mineral-rich water ingestion by ovariectomized fructose-fed Sprague-Dawley rats: effects on sirtuin 1 and glucocorticoid signaling pathways.

OBJECTIVE: Prevention or induction of metabolic disorders and obesity depend on estrogen signaling and/or exogenous factors, such as mineral content in diet. The protective effects of a Portuguese natural mineral-rich water against the induction of metabolic syndrome in fructose-fed male Sprague-Dawley rats have been reported. The present study was designed to assess the impact of this mineral-rich water on fructose-fed estrogen-deficient female Sprague-Dawley rats. METHODS: Ovariectomized rats had access to tap (TWO) or mineral-rich (MWO) waters, with and without 10% fructose (10-wk treatment). A sham-operated (tap water supplied) group was included and each of the five groups included six rats. Plasma biochemical and metabolic parameters were evaluated by routine clinical measurements. Western blotting was used to assess hepatic protein expression of sirtuins (Sirt) 1 and 3, phosphorylated AMP-activated protein kinase-α (p-AMPKα), peroxisome proliferator-activated receptor gamma coactivator-1-α (PGC1α), glucocorticoid receptor, and 11beta-hydroxysteroid dehydrogenase type 1 (11ßHSD1). RESULTS: Ovariectomy increased plasma total cholesterol (46%/P < 0.05), but had no significant effects on hepatic protein expression. Fructose intake by ovariectomized rats increased PGC1α and 11ßHSD1 (fructose in tap water [TWFO] vs TWO: 65%/P < 0.05 and 38%/P = 0.05, respectively) as well as glucocorticoid receptor (TWFO and fructose in natural mineral-rich water [MWFO] vs TWO and MWO: 107%/P = 0.05 and 182%/P < 0.05, respectively). Mineral-rich water ingestion exerted an increasing shape on Sirt1 (MWO vs TWO: 76%/P < 0.05; MWFO vs TWFO: 76%/P = 0.06), PGC1α (MWO vs TWO: 77%/P < 0.01), p-AMPKα (MWO vs TWO: 152%/P = 0.01; MWFO vs TWFO: 107%/P = 0.01), and 11ßHSD1 (MWO vs TWO: 91%/P = 0.05; MWFO vs TWFO: 47%/P = 0.05). CONCLUSIONS: Mineral-rich water ingestion may have a prime role on the activation of Sirt1 signaling and the modulation of glucocorticoid signaling in the postmenopause.

Altered virulence potential of Salmonella Enteritidis cultured in different foods: A cumulative effect of differential gene expression and immunomodulation.

Salmonella enterica serovars Enteritidis (S. Enteritidis) is one of the most common causes of food borne illness. Bacterial growth environment plays an important role in regulating gene expression thereby affecting the virulence profile of the bacteria. Different foods present diverse growth conditions which may affect the pathogenic potential of the bacteria. In the present study, the effect of food environments on the pathogenic potential of S. Enteritidis has been evaluated. S. Enteritidis was grown in different foods e.g. egg white, peanut butter and milk, and virulent phenotypes were compared to those grown in Luria Bertani broth. In-vivo experiments in C57BL/6 mice revealed S. Enteritidis grown in egg white did not induce significant (p<0.001) production of proinflammatory cytokines in mice and were unable to cause colitis despite efficient colonization in cecum, mesenteric lymph node, spleen and liver. Further studies revealed that bacteria grown in LB activated MAP Kinase and NFκB pathways efficiently, while those grown in egg white poorly activated the above pathways which can account for the decreased production of proinflammatory cytokines. qRT PCR analysis revealed SPI-1 effectors were downregulated in bacteria grown in egg white. Interestingly, bacteria grown in egg white showed reversal of phenotype upon change in growth media to LB. Additionally, bacteria grown in milk and peanut butter showed different degrees of virulence in mice as compared to those grown in LB media. Thus, the present study demonstrates that, S. Enteritidis grown in egg white colonizes systemic sites without causing colitis in a mouse model, while bacteria grown in milk and peanut butter show different pathogenicity profiles suggesting that food environments significantly affect the pathogenicity of S. Enteritidis.