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Valentine Y, Nikolajczyk BS. T cells in obesity-associated inflammation: The devil is in the details. Immunol Rev 2024. [PMID: 38767210 DOI: 10.1111/imr.13354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Obesity presents a significant health challenge, affecting 41% of adults and 19.7% of children in the United States. One of the associated health challenges of obesity is chronic low-grade inflammation. In both mice and humans, T cells in circulation and in the adipose tissue play a pivotal role in obesity-associated inflammation. Changes in the numbers and frequency of specific CD4+ Th subsets and their contribution to inflammation through cytokine production indicate declining metabolic health, that is, insulin resistance and T2D. While some Th subset alterations are consistent between mice and humans with obesity, some changes mainly characterize male mice, whereas female mice often resist obesity and inflammation. However, protection from obesity and inflammation is not observed in human females, who can develop obesity-related T-cell inflammation akin to males. The decline in female sex hormones after menopause is also implicated in promoting obesity and inflammation. Age is a second underappreciated factor for defining and regulating obesity-associated inflammation toward translating basic science findings to the clinic. Weight loss in mice and humans, in parallel with these other factors, does not resolve obesity-associated inflammation. Instead, inflammation persists amid modest changes in CD4+ T cell frequencies, highlighting the need for further research into resolving changes in T-cell function after weight loss. How lingering inflammation after weight loss affecting the common struggle to maintain lower weight is unknown. Semaglutide, a newly popular pharmaceutical used for treating T2D and reversing obesity, holds promise for alleviating obesity-associated health complications, yet its impact on T-cell-mediated inflammation remains unexplored. Further work in this area could significantly contribute to the scientific understanding of the impacts of weight loss and sex/hormones in obesity and obesity-associated metabolic decline.
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Affiliation(s)
- Yolander Valentine
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, Kentucky, USA
| | - Barbara S Nikolajczyk
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, Kentucky, USA
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
- Barnstable Brown Diabetes and Obesity Research Center, University of Kentucky, Lexington, Kentucky, USA
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Barberis M, Rojas López A. Metabolic imbalance driving immune cell phenotype switching in autoimmune disorders: Tipping the balance of T- and B-cell interactions. Clin Transl Med 2024; 14:e1626. [PMID: 38500390 PMCID: PMC10948951 DOI: 10.1002/ctm2.1626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 02/18/2024] [Accepted: 02/25/2024] [Indexed: 03/20/2024] Open
Abstract
The interplay between the immune system and the metabolic state of a cell is intricate. In all phases of an immune response, the corresponding metabolic changes shall occur to support its modulation, in addition to the signalling through the cytokine environment and immune receptor stimulation. While autoimmune disorders may develop because of a metabolic imbalance that modulates switching between T-cell phenotypes, the effects that the interaction between T and B cells have on one another's cellular metabolism are yet to be understood in disease context. Here, we propose a perspective which highlights the potential of targeting metabolism to modulate T- and B-cell subtypes populations as well as T-B and B-T cell interactions to successfully treat autoimmune disorders. Specifically, we envision how metabolic changes can tip the balance of immune cells interactions, through definite mechanisms in both health and disease, to explain phenotype switches of B and T cells. Within this scenario, we highlight targeting metabolism that link inflammation, immunometabolism, epigenetics and ageing, is critical to understand inflammatory disorders. The combination of treatments targeting immune cells that cause (T/B) cell phenotype imbalances, and the metabolic pathways involved, may increase the effectiveness of treatment of autoimmune disorders, and/or ameliorate their symptoms to improve patients' quality of life.
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Affiliation(s)
- Matteo Barberis
- Molecular Systems BiologySchool of BiosciencesFaculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
- Centre for Mathematical and Computational Biology, CMCBUniversity of SurreyGuildfordSurreyUK
- Synthetic Systems Biology and Nuclear OrganizationSwammerdam Institute for Life SciencesUniversity of AmsterdamAmsterdamThe Netherlands
| | - Alejandra Rojas López
- Molecular Systems BiologySchool of BiosciencesFaculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
- Centre for Mathematical and Computational Biology, CMCBUniversity of SurreyGuildfordSurreyUK
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3
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Shaikh SR, Beck MA, Alwarawrah Y, MacIver NJ. Emerging mechanisms of obesity-associated immune dysfunction. Nat Rev Endocrinol 2024; 20:136-148. [PMID: 38129700 DOI: 10.1038/s41574-023-00932-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 12/23/2023]
Abstract
Obesity is associated with a wide range of complications, including type 2 diabetes mellitus, cardiovascular disease, hypertension and nonalcoholic fatty liver disease. Obesity also increases the incidence and progression of cancers, autoimmunity and infections, as well as lowering vaccine responsiveness. A unifying concept across these differing diseases is dysregulated immunity, particularly inflammation, in response to metabolic overload. Herein, we review emerging mechanisms by which obesity drives inflammation and autoimmunity, as well as impairing tumour immunosurveillance and the response to infections. Among these mechanisms are obesity-associated changes in the hormones that regulate immune cell metabolism and function and drive inflammation. The cargo of extracellular vesicles derived from adipose tissue, which controls cytokine secretion from immune cells, is also dysregulated in obesity, in addition to impairments in fatty acid metabolism related to inflammation. Furthermore, an imbalance exists in obesity in the biosynthesis and levels of polyunsaturated fatty acid-derived oxylipins, which control a range of outcomes related to inflammation, such as immune cell chemotaxis and cytokine production. Finally, there is a need to investigate how obesity influences immunity using innovative model systems that account for the heterogeneous nature of obesity in the human population.
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Affiliation(s)
- Saame Raza Shaikh
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Melinda A Beck
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Yazan Alwarawrah
- Department of Paediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nancie J MacIver
- Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Paediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Mitchelson KAJ, O’Connell F, O’Sullivan J, Roche HM. Obesity, Dietary Fats, and Gastrointestinal Cancer Risk-Potential Mechanisms Relating to Lipid Metabolism and Inflammation. Metabolites 2024; 14:42. [PMID: 38248845 PMCID: PMC10821017 DOI: 10.3390/metabo14010042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/23/2024] Open
Abstract
Obesity is a major driving factor in the incidence, progression, and poor treatment response in gastrointestinal cancers. Herein, we conducted a comprehensive analysis of the impact of obesity and its resulting metabolic perturbations across four gastrointestinal cancer types, namely, oesophageal, gastric, liver, and colorectal cancer. Importantly, not all obese phenotypes are equal. Obese adipose tissue heterogeneity depends on the location, structure, cellular profile (including resident immune cell populations), and dietary fatty acid intake. We discuss whether adipose heterogeneity impacts the tumorigenic environment. Dietary fat quality, in particular saturated fatty acids, promotes a hypertrophic, pro-inflammatory adipose profile, in contrast to monounsaturated fatty acids, resulting in a hyperplastic, less inflammatory adipose phenotype. The purpose of this review is to examine the impact of obesity, including dietary fat quality, on adipose tissue biology and oncogenesis, specifically focusing on lipid metabolism and inflammatory mechanisms. This is achieved with a particular focus on gastrointestinal cancers as exemplar models of obesity-associated cancers.
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Affiliation(s)
- Kathleen A. J. Mitchelson
- Nutrigenomics Research Group, UCD Conway Institute, UCD Institute of Food and Health, and School of Public Health, Physiotherapy and Sports Science, University College Dublin, D04 H1W8 Dublin, Ireland
| | - Fiona O’Connell
- Department of Surgery, Trinity St. James’s Cancer Institute and Trinity Translational Medicine Institute, St. James’s Hospital and Trinity College Dublin, D08 W9RT Dublin, Ireland
| | - Jacintha O’Sullivan
- Department of Surgery, Trinity St. James’s Cancer Institute and Trinity Translational Medicine Institute, St. James’s Hospital and Trinity College Dublin, D08 W9RT Dublin, Ireland
| | - Helen M. Roche
- Nutrigenomics Research Group, UCD Conway Institute, UCD Institute of Food and Health, and School of Public Health, Physiotherapy and Sports Science, University College Dublin, D04 H1W8 Dublin, Ireland
- Institute for Global Food Security, School of Biological Sciences, Queens University Belfast, Belfast BT9 5DL, UK
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Frasca D, Romero M, Diaz A, Blomberg BB. Obesity accelerates age defects in B cells, and weight loss improves B cell function. Immun Ageing 2023; 20:35. [PMID: 37460937 PMCID: PMC10351107 DOI: 10.1186/s12979-023-00361-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/11/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND We have previously shown that obesity accelerates age-associated defects in B cell function and antibody production leading to decreased secretion of protective antibodies and increased autoimmunity. We wanted to evaluate if obese adults enrolled in a voluntary weight reduction program had higher protective and lower autoimmune antibody responses similar to those observed in lean adults. METHODS Experiments were performed using blood isolated from an established cohort of female lean adult and elderly individuals, as well as from the blood of female adults with obesity, before and after a voluntary weight reduction program in which their Body Mass Index (BMI) was reduced 10-34% in 12 months. All participants were vaccinated with the Trivalent Inactivated Influenza vaccine. Serum samples were evaluated for the presence of pro-inflammatory cytokines and adipokines, vaccine-specific antibodies and autoimmune antibodies. We evaluated the composition of the B cell pool by flow cytometry, the expression of RNA for class switch transcription factors and pro-inflammatory markers by qPCR, the in vitro secretion of pro- and anti-inflammatory cytokines and their capacity to induce pro-inflammatory T cells. RESULTS Obesity, similar to aging, induced increased serum levels of pro-inflammatory cytokines and autoimmune antibodies, while vaccine-specific antibodies were reduced. In agreement with the serum results, the B cell pool of obese adults and elderly individuals was enriched in pro-inflammatory B cell subsets and was characterized by higher expression of markers associated with cell senescence, higher levels of T-bet, the transcription factor for autoimmune antibodies and lower levels of E47, the transcription factor associated with protective responses to the influenza vaccine. B cells from obese adults and elderly individuals were also able to secrete inflammatory cytokines and support the generation of inflammatory T cells. All these pro-inflammatory characteristics of B cells from obese individuals were significantly attenuated, but not completely reversed, by weight loss. CONCLUSIONS Although the results from our small observational study show that obesity-induced dysfunctional B cell responses, similar to those occurring during aging, are ameliorated in some but not all obese individuals after weight loss, the effects of body weight loss on mechanistic pathways are largely missing and deserve further investigation.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, RMSB 3153, 1600 NW 10thAve, Miami, FL, 33136, USA.
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - Maria Romero
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, RMSB 3153, 1600 NW 10thAve, Miami, FL, 33136, USA
| | - Alain Diaz
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, RMSB 3153, 1600 NW 10thAve, Miami, FL, 33136, USA
| | - Bonnie B Blomberg
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, RMSB 3153, 1600 NW 10thAve, Miami, FL, 33136, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
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Geitgey DK, Lee M, Cottrill KA, Jaffe M, Pilcher W, Bhasin S, Randall J, Ross AJ, Salemi M, Castillo-Castrejon M, Kilgore MB, Brown AC, Boss JM, Johnston R, Fitzpatrick AM, Kemp ML, English R, Weaver E, Bagchi P, Walsh R, Scharer CD, Bhasin M, Chandler JD, Haynes KA, Wellberg EA, Henry CJ. The 'omics of obesity in B-cell acute lymphoblastic leukemia. J Natl Cancer Inst Monogr 2023; 2023:12-29. [PMID: 37139973 PMCID: PMC10157791 DOI: 10.1093/jncimonographs/lgad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/12/2023] [Accepted: 03/17/2023] [Indexed: 05/05/2023] Open
Abstract
The obesity pandemic currently affects more than 70 million Americans and more than 650 million individuals worldwide. In addition to increasing susceptibility to pathogenic infections (eg, SARS-CoV-2), obesity promotes the development of many cancer subtypes and increases mortality rates in most cases. We and others have demonstrated that, in the context of B-cell acute lymphoblastic leukemia (B-ALL), adipocytes promote multidrug chemoresistance. Furthermore, others have demonstrated that B-ALL cells exposed to the adipocyte secretome alter their metabolic states to circumvent chemotherapy-mediated cytotoxicity. To better understand how adipocytes impact the function of human B-ALL cells, we used a multi-omic RNA-sequencing (single-cell and bulk transcriptomic) and mass spectroscopy (metabolomic and proteomic) approaches to define adipocyte-induced changes in normal and malignant B cells. These analyses revealed that the adipocyte secretome directly modulates programs in human B-ALL cells associated with metabolism, protection from oxidative stress, increased survival, B-cell development, and drivers of chemoresistance. Single-cell RNA sequencing analysis of mice on low- and high-fat diets revealed that obesity suppresses an immunologically active B-cell subpopulation and that the loss of this transcriptomic signature in patients with B-ALL is associated with poor survival outcomes. Analyses of sera and plasma samples from healthy donors and those with B-ALL revealed that obesity is associated with higher circulating levels of immunoglobulin-associated proteins, which support observations in obese mice of altered immunological homeostasis. In all, our multi-omics approach increases our understanding of pathways that may promote chemoresistance in human B-ALL and highlight a novel B-cell-specific signature in patients associated with survival outcomes.
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Affiliation(s)
- Delaney K Geitgey
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
| | - Miyoung Lee
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
| | - Kirsten A Cottrill
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Maya Jaffe
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - William Pilcher
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Swati Bhasin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Jessica Randall
- Emory Integrated Computational Core, Emory University, Atlanta, GA, USA
| | - Anthony J Ross
- Riley Children’s Health, Indiana University Health, Indianapolis, IN, USA
| | - Michelle Salemi
- Proteomics Core Facility, University of California Davis Genome Center, Davis, 95616, CA
| | - Marisol Castillo-Castrejon
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Matthew B Kilgore
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Ayjha C Brown
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
| | - Jeremy M Boss
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Atlanta, GA, USA
| | - Rich Johnston
- Emory Integrated Computational Core, Emory University, Atlanta, GA, USA
| | - Anne M Fitzpatrick
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Melissa L Kemp
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Emory Integrated Proteomics Core, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Eric Weaver
- Shimadzu Scientific Instruments, Columbia, MD, USA
| | - Pritha Bagchi
- Emory Integrated Proteomics Core, Emory University School of Medicine, Atlanta, GA, USA
| | - Ryan Walsh
- Shimadzu Scientific Instruments, Columbia, MD, USA
| | - Christopher D Scharer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Atlanta, GA, USA
| | - Manoj Bhasin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Winship Cancer Institute, Atlanta, GA, USA
| | - Joshua D Chandler
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Karmella A Haynes
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Winship Cancer Institute, Atlanta, GA, USA
| | - Elizabeth A Wellberg
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Curtis J Henry
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Aflac Cancer and Blood Disorders Center, Atlanta, GA, USA
- Children’s Healthcare of Atlanta, Atlanta, GA, USA
- Winship Cancer Institute, Atlanta, GA, USA
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Li K, Romero M, Cañardo M, Garcia D, Diaz A, Blomberg BB, Frasca D. B cells from old mice induce the generation of inflammatory T cells through metabolic pathways. Mech Ageing Dev 2023; 209:111742. [PMID: 36309082 DOI: 10.1016/j.mad.2022.111742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 11/07/2022]
Abstract
We have measured the capacity of B cells from young and old mice to induce the differentiation of naïve CD4 + T cells from young mice into pro-inflammatory subsets. We found that only B cells from old mice are inflammatory and induce in vitro secretion of the pro-inflammatory cytokines IL-17A and IFN-γ by T cells. In co-culture experiments, B cells from old mice showed a strong helper function on T cells from young mice, making them pro-inflammatory, and this effect is regulated by metabolic pathways, mainly anaerobic glycolysis, leading to increased RNA expression of the enzyme lactate dehydrogenase (LDHA) and increased secretion of lactate. These results have indicated that lactate is a crucial player of the B cell-induced polarization of T cells. When we measured the effects of lactate on isolated CD4 + T cells from young mice, we found that lactate increases RNA expression of LDHA, secretion of pro-inflammatory cytokines and NF-kB activation. Moreover, lactate effects in culture can be abrogated in the presence of the specific inhibitor of LDHA, FX11. These results altogether may have relevant clinical implications and suggest novel targets for therapeutic interventions in patients with inflammatory conditions and diseases.
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Affiliation(s)
- Kevin Li
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA
| | - Maria Romero
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA
| | - Macarena Cañardo
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA
| | - Denisse Garcia
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA
| | - Alain Diaz
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA
| | - Bonnie B Blomberg
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA; Sylvester Comprehensive Cancer Center University of Miami Miller School of Medicine, Miami, FL USA
| | - Daniela Frasca
- Department of Microbiology and Immunology and University of Miami Miller School of Medicine, Miami, FL USA; Sylvester Comprehensive Cancer Center University of Miami Miller School of Medicine, Miami, FL USA.
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Frasca D. Several areas of overlap between obesity and aging indicate obesity as a biomarker of accelerated aging of human B cell function and antibody responses. Immun Ageing 2022; 19:48. [PMID: 36289515 PMCID: PMC9598013 DOI: 10.1186/s12979-022-00301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 09/19/2022] [Indexed: 11/10/2022]
Abstract
Aging and obesity are high risk factors for several conditions and diseases. They are both associated with systemic inflammation and they are both ameliorated by a healthy life style, suggesting that they may share cellular and molecular pathways and underlying mechanisms. A close relationship between aging and obesity is also supported by the observation that the aging overweight/obese population is increasing worldwide, and mechanisms involved will be presented here. A focus of our work is to evaluate if obesity may be considered a good biomarker of accelerated aging of human antibody responses. We will summarize our published results showing the effects of obesity in accelerating age defects in the peripheral B cell pool and how these lead to dysfunctional humoral immunity.
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Affiliation(s)
- Daniela Frasca
- Department of Microbiology and Immunology and Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, RMSB 3153, 1600 NW 10th Ave, Miami, FL, 33136, USA.
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Role of B Lymphocytes in the Pathogenesis of NAFLD: A 2022 Update. Int J Mol Sci 2022; 23:ijms232012376. [PMID: 36293233 PMCID: PMC9603875 DOI: 10.3390/ijms232012376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/09/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022] Open
Abstract
Non-alcoholic fatty liver disease and its related complications are becoming one of the most important health problems globally. The liver functions as both a metabolic and an immune organ. The crosstalk between hepatocytes and intrahepatic immune cells plays a key role in coordinating a dual function of the liver in terms of the protection of the host from antigenic overload as a result of receiving nutrients and gut microbiota antigenic stimulation via facilitating immunologic tolerance. B cells are the most abundant lymphocytes in the liver. The crucial role of intrahepatic B cells in energy metabolism under different immune conditions is now emerging in the literature. The accumulating evidence has demonstrated that the antibodies and cytokines produced by B cells in the microenvironment play key and distinct roles in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Herein, we have aimed to consolidate and update the current knowledge about the pathophysiological roles of B cells as well as the underlying mechanisms in energy metabolism. Understanding how B cells can exacerbate and suppress liver damage by exploiting the antibodies and cytokines they produce will be of great importance for designing B-cell targeting therapies to treat various liver diseases.
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10
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Abstract
Aging is associated with systemic inflammation and decreased production of protective antibodies while the production of autoimmune antibodies is increased. Our results have shown that the human obese adipose tissue (AT), which increases in size with aging, contributes to systemic and B cell intrinsic inflammation, reduced protective and increased pathogenic B cell responses leading to increased secretion of autoimmune antibodies. With this R56 funding, we have been able to investigate the cellular and molecular mechanisms by which the human obese AT induces intrinsic B cell inflammation and dysfunctional B cell responses, stimulates the secretion of autoimmune antibodies, whose specificity has been characterized, and engages different AT cell types in antigen presentation pathways to allow secretion of these autoimmune antibodies. Briefly, immune cells are recruited to the AT by chemokines released by both non-immune (adipocytes) and by resident and infiltrating immune cells. We have identified several mechanisms responsible for the release of “self” antigens, and we have shown that reduced oxygen availability and hypoxia, cell cytotoxicity and DNA damage induce cell death and lead to further release of pro-inflammatory cytokines, “self” protein antigens, cell-free DNA and lipids. We have also identified different antigen presenting cells in the AT, responsible for the activation of pathogenic B cells, class switch and secretion of autoimmune IgG antibodies. The experiments performed have allowed the discovery of novel mechanisms for pathogenic responses and the identification of pathways to target in order to promote better humoral immunity during aging.
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