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1.
Cell Metab ; 36(2): 229-239, 2024 02 06.
Article in English | MEDLINE | ID: mdl-38218187

ABSTRACT

Tissue regulatory T cells (Tregs) exert pivotal functions in both immune and metabolic regulation, maintaining local tissue homeostasis, integrity, and function. Accordingly, Tregs play a crucial role in controlling obesity-induced inflammation and supporting efficient muscle function and repair. Depending on the tissue context, Tregs are characterized by unique transcriptomes, growth, and survival factors and T cell receptor (TCR) repertoires. This functional specialization offers the potential to selectively target context-specific Treg populations, tailoring therapeutic strategies to specific niches, thereby minimizing potential side effects. Here, we discuss challenges and perspectives for niche-specific Treg targeting, which holds promise for highly efficient and precise medical interventions to combat metabolic disease.


Subject(s)
Metabolic Diseases , T-Lymphocytes, Regulatory , Humans , Homeostasis , Metabolic Diseases/metabolism
2.
Mol Metab ; 64: 101565, 2022 10.
Article in English | MEDLINE | ID: mdl-35944899

ABSTRACT

BACKGROUND: The highly complex pathogenesis of Type 1 Diabetes is driven by several immune cell types with both effector and regulatory characteristics, which ultimately ends in the destruction of the insulin-producing beta cells. There are multiple layers of interaction between these immune cell populations and the pancreatic islets. SCOPE OF REVIEW: In this review article, we aim to discuss important recent insights into the multiple layers of interaction between immune cell populations and the pancreatic islets. Specifically, we discuss the environment where immune and beta cell interactions occur, the key cell types and molecules involved, and the outcomes of these interactions. MAJOR CONCLUSIONS: Most of the molecular mechanisms underlying aberrant immune cell activation and impaired immune tolerance remain insufficiently understood, which hinders the development of efficient prevention and treatment strategies. In order to overcome this knowledge gap, a better understanding of the complex interactions of immune cells and beta cells, including both the underlying protective and pathogenic mechanisms is urgently required.


Subject(s)
Diabetes Mellitus, Type 1 , Insulin-Secreting Cells , Islets of Langerhans , Autoimmunity , Cell Communication , Humans , Insulin-Secreting Cells/pathology
3.
Front Immunol ; 12: 643544, 2021.
Article in English | MEDLINE | ID: mdl-33679808

ABSTRACT

Immunodeficient mice engrafted with a functional human immune system [Human immune system (HIS) mice] have paved the way to major advances for personalized medicine and translation of immune-based therapies. One prerequisite for advancing personalized medicine is modeling the immune system of individuals or disease groups in a preclinical setting. HIS mice engrafted with peripheral blood mononuclear cells have provided fundamental insights in underlying mechanisms guiding immune activation vs. regulation in several diseases including cancer. However, the development of Graft-vs.-host disease restrains relevant long-term studies in HIS mice. Alternatively, engraftment with hematopoietic stem cells (HSCs) enables mimicking different disease stages, however, low frequencies of HSCs in peripheral blood of adults impede engraftment efficacy. One possibility to overcome those limitations is the use of patient-derived induced pluripotent stem cells (iPSCs) reprogrammed into HSCs, a challenging process which has recently seen major advances. Personalized HIS mice bridge research in mice and human diseases thereby facilitating the translation of immunomodulatory therapies. Regulatory T cells (Tregs) are important mediators of immune suppression and thereby contribute to tumor immune evasion, which has made them a central target for cancer immunotherapies. Importantly, studying Tregs in the human immune system in vivo in HIS mice will help to determine requirements for efficient Treg-targeting. In this review article, we discuss advances on personalized HIS models using reprogrammed iPSCs and review the use of HIS mice to study requirements for efficient targeting of human Tregs for personalized cancer immunotherapies.


Subject(s)
Immune Tolerance , Immunotherapy , Models, Immunological , Neoplasms , T-Lymphocytes, Regulatory/immunology , Tumor Escape , Animals , Humans , Mice , Neoplasms/immunology , Neoplasms/therapy
4.
Front Endocrinol (Lausanne) ; 11: 606322, 2020.
Article in English | MEDLINE | ID: mdl-33329406

ABSTRACT

The important role of microRNAs as major modulators of various physiological processes, including immune regulation and homeostasis, has been increasingly recognized. Consequently, aberrant miRNA expression contributes to the defective regulation of T cell development, differentiation, and function. This can result in immune activation and impaired tolerance mechanisms, which exert a cardinal function for the onset of islet autoimmunity and the progression to T1D. The specific impact of miRNAs for immune regulation and how miRNAs and their downstream targets are involved in the pathogenesis of islet autoimmunity and T1D has been investigated recently. These studies revealed that increased expression of individual miRNAs is involved in several layers of tolerance impairments, such as inefficient Treg induction and Treg instability. The targeted modulation of miRNAs using specific inhibitors, resulting in improved immune homeostasis, as well as improved methods for the targeting of miRNAs, suggest that miRNAs, especially in T cells, are a promising target for the reestablishment of immune tolerance.


Subject(s)
Autoimmunity/genetics , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Islets of Langerhans/immunology , MicroRNAs/immunology , Animals , Gene Expression Regulation , Humans , Immune Tolerance , T-Lymphocytes, Regulatory/immunology
5.
Curr Diab Rep ; 20(9): 41, 2020 07 28.
Article in English | MEDLINE | ID: mdl-32725277

ABSTRACT

PURPOSE OF REVIEW: Regulatory T cells (Tregs) are critical contributors to immune homeostasis and their dysregulation can lead to the loss of immune tolerance and autoimmune diseases like type 1 diabetes (T1D). Recent studies have highlighted microRNAs (miRNAs) as important regulators of the immune system, by fine-tuning relevant genes in various immune cell types. In this review article, we discuss recent insights into miRNA regulation of immune tolerance and activation. Specifically, we discuss how the dysregulation of miRNAs in T cells contributes to their aberrant function and the onset of islet autoimmunity, as well as their potential as targets of novel intervention strategies to interfere with autoimmune activation. RECENT FINDINGS: Several studies have shown that the dysregulation of individual miRNAs in T cells can contribute to impaired immune tolerance, contributing to onset and progression of islet autoimmunity. Importantly, the targeting of these miRNAs, including miR-92a, miR-142-3p and miR-181a, resulted in relevant effects on downstream pathways, improved Treg function and reduced islet autoimmunity in murine models. miRNAs are critical regulators of immune homeostasis and the dysregulation of individual miRNAs in T cells contributes to aberrant T cell function and autoimmunity. The specific targeting of individual miRNAs could improve Treg homeostasis and therefore limit overshooting T cell activation and islet autoimmunity.


Subject(s)
Autoimmune Diseases , Diabetes Mellitus, Type 1 , MicroRNAs , Animals , Autoimmunity , Diabetes Mellitus, Type 1/genetics , Humans , Mice , MicroRNAs/genetics , T-Lymphocytes, Regulatory
6.
Nat Commun ; 10(1): 5697, 2019 12 13.
Article in English | MEDLINE | ID: mdl-31836704

ABSTRACT

In type 1 diabetes, the appearance of islet autoantibodies indicates the onset of islet autoimmunity, often many years before clinical symptoms arise. While T cells play a major role in the destruction of pancreatic beta cells, molecular underpinnings promoting aberrant T cell activation remain poorly understood. Here, we show that during islet autoimmunity an miR142-3p/Tet2/Foxp3 axis interferes with the efficient induction of regulatory T (Treg) cells, resulting in impaired Treg stability in mouse and human. Specifically, we demonstrate that miR142-3p is induced in islet autoimmunity and that its inhibition enhances Treg induction and stability, leading to reduced islet autoimmunity in non-obese diabetic mice. Using various cellular and molecular approaches we identify Tet2 as a direct target of miR142-3p, thereby linking high miR142-3p levels to epigenetic remodeling in Tregs. These findings offer a mechanistic model where during islet autoimmunity miR142-3p/Tet2-mediated Treg instability contributes to autoimmune activation and progression.


Subject(s)
Autoimmunity/genetics , DNA-Binding Proteins/genetics , Diabetes Mellitus, Type 1/immunology , MicroRNAs/metabolism , Proto-Oncogene Proteins/genetics , T-Lymphocytes, Regulatory/immunology , Animals , Cell Differentiation/genetics , Cell Differentiation/immunology , Cells, Cultured , Child , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/genetics , Dioxygenases , Epigenesis, Genetic/immunology , Gene Expression Regulation/immunology , Gene Knockdown Techniques , Humans , Islets of Langerhans/immunology , Male , Mice, Knockout , MicroRNAs/agonists , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , Primary Cell Culture
7.
Mol Metab ; 27S: S122-S128, 2019 09.
Article in English | MEDLINE | ID: mdl-31500823

ABSTRACT

BACKGROUND: microRNAs (miRNAs) have emerged as critical contributors to immune regulation and homeostasis, and their dysregulation is involved in the aberrant differentiation and function of T cell subsets. In type 1 diabetes (T1D), the clinically overt disease is preceded by a presymptomatic phase which is marked by the presence of islet autoantibodies while the individual is still normoglycemic. Recent analyses revealed impaired regulatory T (Treg) cell induction from naive CD4+ T cells during this early phase of autoimmunity. SCOPE OF THE REVIEW: In this review article, we aim to discuss important recent insights into miRNA regulation of immune homeostasis and activation. Specifically, we highlight the role of miRNAs as biomarkers in autoimmunity and T1D as well as the contribution of specific miRNAs and their downstream pathways to the onset and progression of islet immunity. Furthermore, we focus on critical next steps required to establish miRNAs as biomarkers to predict disease onset and progression and as novel targets of future prevention and treatment strategies to control autoimmunity. MAJOR CONCLUSIONS: Several recent studies have provided considerable insight into the miRNA regulation of immune homeostasis and how dysregulated miRNAs contribute to onset and progression of islet autoimmunity. Specifically, high levels of individual miRNAs such as miR92a and miR181a are involved in impaired Treg induction during the onset of islet autoimmunity, thereby contributing to disease pathogenesis. The recent advancements in the field suggest miRNAs as potential biomarkers for islet autoimmunity and their direct targeting, especially in a T cell-specific manner, could contribute to the reestablishment of immune homeostasis and ultimately interfere with the onset of islet autoimmunity.


Subject(s)
Autoimmunity/genetics , Diabetes Mellitus, Type 1/immunology , Islets of Langerhans/immunology , MicroRNAs/genetics , MicroRNAs/immunology , T-Lymphocytes, Regulatory/immunology , Animals , Humans
8.
Sci Transl Med ; 10(422)2018 01 03.
Article in English | MEDLINE | ID: mdl-29298866

ABSTRACT

Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)-mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3+ regulatory T cell (Treg) induction in vitro. Accordingly, Treg induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect Treg induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)-mediated NFAT5, which interferes with FoxP3+ Treg induction. Blocking miRNA181a or NFAT5 increases Treg induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.


Subject(s)
Diabetes Mellitus, Type 1/metabolism , MicroRNAs/metabolism , NFATC Transcription Factors/metabolism , Animals , Antagomirs , CD4-Positive T-Lymphocytes/metabolism , Diabetes Mellitus, Type 1/genetics , Female , Forkhead Transcription Factors/genetics , Forkhead Transcription Factors/metabolism , Humans , Immunogenetics , Mice , Mice, Mutant Strains , MicroRNAs/genetics , NFATC Transcription Factors/genetics
9.
Cell Metab ; 26(3): 475-492.e7, 2017 Sep 05.
Article in English | MEDLINE | ID: mdl-28877454

ABSTRACT

Obesity and type 2 diabetes are associated with metabolic defects and adipose tissue inflammation. Foxp3+ regulatory T cells (Tregs) control tissue homeostasis by counteracting local inflammation. However, if and how T cells interlink environmental influences with adipocyte function remains unknown. Here, we report that enhancing sympathetic tone by cold exposure, beta3-adrenergic receptor (ADRB3) stimulation or a short-term high-calorie diet enhances Treg induction in vitro and in vivo. CD4+ T cell proteomes revealed higher expression of Foxp3 regulatory networks in response to cold or ADRB3 stimulation in vivo reflecting Treg induction. Specifically, Ragulator-interacting protein C17orf59, which limits mTORC1 activity, was upregulated in CD4+ T cells by either ADRB3 stimulation or cold exposure, suggesting contribution to Treg induction. By loss- and gain-of-function studies, including Treg depletion and transfers in vivo, we demonstrated that a T cell-specific Stat6/Pten axis links cold exposure or ADRB3 stimulation with Foxp3+ Treg induction and adipose tissue function. Our findings offer a new mechanistic model in which tissue-specific Tregs maintain adipose tissue function.


Subject(s)
Adipose Tissue, Brown/metabolism , Adipose Tissue, White/metabolism , PTEN Phosphohydrolase/metabolism , STAT6 Transcription Factor/metabolism , Animals , Cold Temperature , Female , Forkhead Transcription Factors/metabolism , Mice, Inbred BALB C , Proteome/metabolism , Receptors, Adrenergic, beta/metabolism , Signal Transduction , T-Lymphocytes, Regulatory/metabolism , Uncoupling Protein 1/metabolism
10.
Proc Natl Acad Sci U S A ; 113(43): E6659-E6668, 2016 10 25.
Article in English | MEDLINE | ID: mdl-27791035

ABSTRACT

Aberrant immune activation mediated by T effector cell populations is pivotal in the onset of autoimmunity in type 1 diabetes (T1D). T follicular helper (TFH) cells are essential in the induction of high-affinity antibodies, and their precursor memory compartment circulates in the blood. The role of TFH precursors in the onset of islet autoimmunity and signaling pathways regulating their differentiation is incompletely understood. Here, we provide direct evidence that during onset of islet autoimmunity, the insulin-specific target T-cell population is enriched with a C-X-C chemokine receptor type 5 (CXCR5)+CD4+ TFH precursor phenotype. During onset of islet autoimmunity, the frequency of TFH precursors was controlled by high expression of microRNA92a (miRNA92a). miRNA92a-mediated TFH precursor induction was regulated by phosphatase and tension homolog (PTEN) - phosphoinositol-3-kinase (PI3K) signaling involving PTEN and forkhead box protein O1 (Foxo1), supporting autoantibody generation and triggering the onset of islet autoimmunity. Moreover, we identify Krueppel-like factor 2 (KLF2) as a target of miRNA92a in regulating human TFH precursor induction. Importantly, a miRNA92a antagomir completely blocked induction of human TFH precursors in vitro. More importantly, in vivo application of a miRNA92a antagomir to nonobese diabetic (NOD) mice with ongoing islet autoimmunity resulted in a significant reduction of TFH precursors in peripheral blood and pancreatic lymph nodes. Moreover, miRNA92a antagomir application reduced immune infiltration and activation in pancreata of NOD mice as well as humanized NOD Scid IL2 receptor gamma chain knockout (NSG) human leucocyte antigen (HLA)-DQ8 transgenic animals. We therefore propose that miRNA92a and the PTEN-PI3K-KLF2 signaling network could function as targets for innovative precision medicines to reduce T1D islet autoimmunity.


Subject(s)
Autoimmunity , Diabetes Mellitus, Type 1/immunology , Kruppel-Like Transcription Factors/immunology , MicroRNAs/immunology , PTEN Phosphohydrolase/immunology , T-Lymphocytes, Helper-Inducer/immunology , Adolescent , Animals , Antagomirs/genetics , Antagomirs/immunology , Autoantibodies/biosynthesis , Child , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/pathology , Female , Forkhead Box Protein O1/genetics , Forkhead Box Protein O1/immunology , Gene Expression Regulation , Humans , Islets of Langerhans/immunology , Islets of Langerhans/pathology , Kruppel-Like Transcription Factors/genetics , Male , Mice , Mice, Inbred NOD , Mice, Transgenic , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , PTEN Phosphohydrolase/genetics , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/immunology , Primary Cell Culture , Receptors, CXCR5/genetics , Receptors, CXCR5/immunology , Signal Transduction , T-Lymphocytes, Helper-Inducer/pathology
11.
Curr Diab Rep ; 16(8): 75, 2016 08.
Article in English | MEDLINE | ID: mdl-27324759

ABSTRACT

The development of multiple disease-relevant autoantibodies is a hallmark of autoimmune diseases. In autoimmune type 1 diabetes (T1D), a variable time frame of autoimmunity precedes the clinically overt disease. The relevance of T follicular helper (TFH) cells for the immune system is increasingly recognized. Their pivotal contribution to antibody production by providing help to germinal center (GC) B cells facilitates the development of a long-lived humoral immunity. Their complex differentiation process, involving various stages and factors like B cell lymphoma 6 (Bcl6), is strictly controlled, as anomalous regulation of TFH cells is connected with immunopathologies. While the adverse effects of a TFH cell-related insufficient humoral immunity are obvious, the role of increased TFH frequencies in autoimmune diseases like T1D is currently highlighted. High levels of autoantigen trigger an excessive induction of TFH cells, consequently resulting in the production of autoantibodies. Therefore, TFH cells might provide promising approaches for novel therapeutic strategies.


Subject(s)
Autoimmunity/immunology , T-Lymphocytes, Helper-Inducer/immunology , Biomarkers/metabolism , Cell Differentiation/immunology , Diabetes Mellitus, Type 1/immunology , Diabetes Mellitus, Type 1/pathology , Homeostasis , Humans , T-Lymphocytes, Helper-Inducer/pathology
12.
Nat Commun ; 7: 10991, 2016 Mar 15.
Article in English | MEDLINE | ID: mdl-26975663

ABSTRACT

Immune tolerance is executed partly by Foxp3(+)regulatory T (Treg) cells, which suppress autoreactive T cells. In autoimmune type 1 diabetes (T1D) impaired tolerance promotes destruction of insulin-producing ß-cells. The development of autoantigen-specific vaccination strategies for Foxp3(+)Treg-induction and prevention of islet autoimmunity in patients is still in its infancy. Here, using human haematopoietic stem cell-engrafted NSG-HLA-DQ8 transgenic mice, we provide direct evidence for human autoantigen-specific Foxp3(+)Treg-induction in vivo. We identify HLA-DQ8-restricted insulin-specific CD4(+)T cells and demonstrate efficient human insulin-specific Foxp3(+)Treg-induction upon subimmunogenic vaccination with strong agonistic insulin mimetopes in vivo. Induced human Tregs are stable, show increased expression of Treg signature genes such as Foxp3, CTLA4, IL-2Rα and TIGIT and can efficiently suppress effector T cells. Such Foxp3(+)Treg-induction does not trigger any effector T cells. These T1D vaccine candidates could therefore represent an expedient improvement in the challenge to induce human Foxp3(+)Tregs and to develop novel precision medicines for prevention of islet autoimmunity in children at risk of T1D.


Subject(s)
Diabetes Mellitus, Type 1/immunology , Forkhead Transcription Factors/immunology , Gene Expression Regulation/immunology , Insulin/immunology , Lymphocyte Activation/immunology , Self Tolerance/immunology , T-Lymphocytes, Regulatory/immunology , Vaccines/immunology , Adolescent , Adult , Animals , Autoantigens/immunology , Autoimmunity/immunology , CTLA-4 Antigen/genetics , CTLA-4 Antigen/immunology , Child , Child, Preschool , Diabetes Mellitus, Type 1/drug therapy , Female , Forkhead Transcription Factors/genetics , HLA-DQ Antigens/genetics , Hematopoietic Stem Cell Transplantation , Humans , Immune Tolerance/immunology , Interleukin-2 Receptor alpha Subunit/genetics , Interleukin-2 Receptor alpha Subunit/immunology , Male , Mice , Mice, Transgenic , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology , Young Adult
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