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Abstract
Obesity is a chronic progressive disease strongly linked to numerous comorbidities. This is underpinned by a chronic inflammatory environment and significant immune dysregulation. γδ T cells are unconventional T cells that display innate and adaptive characteristics, the predominant one being their independence of MHC restriction. In humans, γδ T cells represent up to 5% of the peripheral blood T cell compartment and are capable of rapidly producing a range of effector cytokines and driving cytotoxic responses. This is critical for protection from both bacterial and viral infections. We investigated circulating γδ T cell metabolic and functional responses in cohorts of people living with obesity (PWO) and people without obesity. We showed that PWO have reduced Vδ2+ T cell frequencies, and their effector responses are diminished following stimulation. We identified that the CD98-LAMTOR5-mTORC1 metabolic axis was critical for functional responses, and demonstrated significant defects in each component of this axis in PWO. Furthermore, STAT5 the initiator of amino acid metabolism was also decreased in PWO. Finally, we showed restoration of this metabolic axis after bariatric surgery, combined with robust improvements in functional responses. Collectively, our data highlighted that obesity drives a reversible dysregulation of Vδ2+ T cells by disrupting cellular metabolism.
Authors
Ciara L. Flynn, Eimear K. Ryan, Cian Davis, Czara A. Kennedy, Katherine G. Egan, Aimee Brennan, Philip Mc Entee, Kirstan Murphy, Niamh Lynam-Lennon, Linda V. Sinclair, Nicholas Jones, Donal O'Shea, Helen M. Heneghan, Andrew E. Hogan
Abstract
Exposure of humans to food insecurity (FI), involving sporadic access and low nutritional quality, is associated with later life development of metabolic disease phenotypes, but mechanisms are poorly understood. We exposed very young rats to a 20-day FI intervention or ad-lib (AL) feeding, using either standard chow (SC) or high fat/high sucrose (HF/HS) diets, followed by continued AL feeding on the respective diets for 10-13 weeks. We found that male, but not female rats subjected to FI on the HF/HS diet had increased body fat percentage, ratio of adipose to body weight, and fat cell size compared to AL rats, coupled with metabolomic and transcriptomic profiles consistent with reduced fatty acid oxidation in the liver and maladaptive remodeling of adipose tissue. These changes were specific to HF/HS feeding and did not occur with SC diet. Our study defines sex- and diet-specific metabolic remodeling responses to FI that may contribute to future disease phenotypes.
Authors
Jie An, Jessica Cannavino, Ashley Williams, Akshay Bareja, Wenxin Tong, Olga Ilkayeva, Michael Muehlbauer, Danhong Lu, Robert A. Hollander, Sarah Armstrong, Rana K. Gupta, Christopher B. Newgard
Abstract
Bone morphogenetic protein-2 (BMP2) is used clinically to promote bone regeneration, but dose-limiting side effects restrict its clinical utility. Canonical Wnt signaling is essential for bone formation, and R-spondin-2 (RSPO2) is a secreted Wnt agonist highly expressed by osteoprogenitors. We found that BMP2 strongly induced RSPO2 during early human mesenchymal stem cell (hMSC) osteoblast differentiation. Recombinant RSPO2 synergized with BMP2 in both hMSCs and MC3T3-E1 preosteoblasts, whereas RSPO2 silencing impaired BMP2-driven osteogenic responses. In a murine critical-size calvarial defect model, co-delivery of RSPO2 and a suboptimal dose of BMP2 yielded significantly more new bone than BMP2 alone, while RSPO2 alone was ineffective. Enhanced canonical Wnt activation with BMP2-RSPO2 co-treatment was shown with an in vivo Wnt reporter mouse. Bulk RNA sequencing of MC3T3-E1 cells revealed that BMP2-RSPO2 co-treatment differentially activated osteogenesis-related genes and pathways compared to BMP2 alone. The guanine exchange factor (GEF), Prex1, was selectively upregulated by BMP2-RSPO2 co-treatment, and was required for RSPO2-mediated enhancement of BMP2-induced osteoblastogenesis. These findings identify RSPO2 as an enhancer of BMP2-driven osteogenesis, amplifying Wnt activation and involving PREX1-dependent signaling. RSPO2 or PREX1 activation may represent a co-therapy that could enhance BMP2 efficacy while mitigating the adverse effects of high-dose BMP2.
Authors
Buchan Jiang, Erin B. Meymarian, Shije Shahin, Jack T. Wilkening, Alexander J. Knights, Archana Sanjay, Tristan Maerz, Yadav Wagley, Kurt D. Hankenson
Abstract
The inflammasome is an innate immune complex responsible for aberrant interleukin-1β (IL-1β) signaling in numerous chronic inflammatory diseases, including gout and Alzheimer’s disease. The inflammasome is composed of several proteins, including the apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC). We developed vaccines targeting various regions of ASC using a Qβ virus-like particle (VLP) platform to assess the efficacy of anti-ASC antibodies for inhibiting inflammasome activity. Using a mouse model of gout, we assessed seven vaccines targeting mouse ASC for their ability to reduce inflammasome activation and neutrophil responses. Three vaccines targeting different regions of the ASC protein (pyrin domain, linker region, and the caspase activation and recruitment domain) successfully targeted ASC, reduced IL-1β, and reduced neutrophil activation. Combining these three vaccines into one cocktail vaccine yielded similar efficacy in the gout model with a favorable safety profile. The combined ASC vaccine also reduced inflammasome levels and pathologically phosphorylated tau in a transgenic mouse model of tauopathy and did not significantly impair host immune responses to bacterial or viral infections. Thus, Qβ-VLP vaccines against ASC can neutralize pathological inflammasome activity across multiple inflammatory disease models.
Authors
Jonathan Hulse, Zachary Villaseñor, Samuel Kress, Kathryn Sánchez, Julianne Peabody, Kimberly A. Morrissey, Alan McNolty, Benjamin Lantz, Laura Gonzalez Bosc, Judy L. Cannon, Seth Daly, Bryce Chackerian, Kiran Bhaskar
Abstract
Hemophagocytic Lymphohistiocytosis (HLH) is a hyperinflammatory syndrome with multiple contributors, often including an infectious trigger. The Macrophage Activation Syndrome (MAS) subtype is linked to marked IL-18 excess, cytotoxic T-lymphocyte (CTL) activation, and natural killer (NK) cell abnormalities. We asked how excess IL-18 shapes NK and CTL responses to viral challenge. Mice with chronic IL-18 overproduction (Il18tg), showed baseline NK-cytopenia and CTL activation resembling MAS-susceptible patients. NK transcriptomes reflected IL-18/IFNg-axis activation and cell cycle upregulation. LCMV infection of Il18tg mice causes HLH/MAS without affecting viral control, but is not a significant NK challenge. Early after infection with NK-dependent mousepox, Il18tg NKs failed to activate appropriately, but CTLs quickly hyperactivated and mousepox control remained intact. Mousepox-infected Il18tg mice then developed signs of HLH/MAS including hepatosplenic necrosis. Their viral control was impaired, possibly because they failed to expand mousepox-specific CTLs. Il18bpKO mice, despite more normal resting lymphocytes, succumbed similarly to viremic HLH/MAS. Transfer of pre-activated NKs into Il18tg mice partially rescued virus-specific CTL responses, viral control, and survival. Thus, excess IL-18 contributes to HLH/MAS via disparate effects on CTL and NK cells, demonstrating a novel, context-specific NK immunodeficiency and highlighting how subtle host-pathogen interactions can affect the mechanisms and treatment rationale of life-threatening HLH/MAS.
Authors
Jemy A. Varghese, Leonardo Huang, Stephen D. Carro, Emily E. Landy, Anastasia Frank-Kamenetskii, Hannah Klinghoffer, Jeremy A. Morrissette, Vinh Dang, Laurence C. Eisenlohr, Scott W. Canna
Abstract
Glioblastoma (GBM) is a lethal brain tumor with a 95% five-year mortality rate, and remains a major unmet clinical need. An innovative approach to target GBM is administration of chimeric antigen receptor (CAR) T cells. In this study we identified B7-H3 as a favorable target antigen for CAR T cell therapy of GBM and developed a B7-H3 targeting CAR T cell. This CAR demonstrates robust, antigen-specific cytolysis and cytokine production, low tonic signaling, and preservation of a stem/naïve cell phenotype. Using orthotopic xenograft models of GBM we show that a single intravenous administration of this B7-H3 targeted CAR confers tumor control, and long-term survival. We identified upregulation of T cell inhibitory ligands PD-L1 and PD-L2 as a mechanism of resistance, and modified our B7-H3 targeting CAR vector to include a secreted a PD-1 blocking scFv. We further demonstrate that concomitant PD-1 blockade by the secreted PD-1 blocking scFv augments the antitumor capabilities of B7-H3-targeting CAR T cells through increased intratumoral infiltration by the CAR T cells and improved effector function. These data demonstrate B7-H3 targeting CAR T cells with concomitant PD-1 blockade is a safe and efficient method for improving the antitumor capacity of CAR T cells for GBM.
Authors
Jonathan F. Khan, Parwiz Abrahimi, Winson Cai, Lauren Dong, Kenny Kwok-Hei Yu, Svena Verma, Yacine Marouf, Sadna Budhu, Tara Pal Chaudhuri, Valeria Estrada Navarro, Mamadou A. Bah, Kelsey Hopland, Yanhong Yang, Terence J. Purdon, Ileana C. Miranda, Viviane Tabar, Jedd D. Wolchok, Taha Merghoub, Renier J. Brentjens
Abstract
Authors
Rocio J. Jimenez-Valdes, Quoc Vo, Alison Morris, Chad Steele, Seyed Mehdi Nouraie, Jonathan K. Alder, Kambez H. Benam
Abstract
Although 95% of serotonin in the human body is produced in the gastrointestinal tract, most prior research work has focused on the brain. Despite its abundance in the gut, serotonin’s role in early intestinal development remains poorly understood. Here we show that serotonin is detected in both the small intestine and large intestine as early as 14 to 15 weeks gestational age. Using single-cell transcriptomics with histological validation, we generated a spatiotemporal atlas of serotonin and serotonin-related genes in the human gut from first trimester to late adulthood. The serotonin synthesis gene, TPH1, was exclusively expressed in enteroendocrine cells at all time points analyzed, with the highest expression in the second trimester. The serotonin reuptake gene, SLC6A4, was largely restricted to mature absorptive enterocytes and increased postnatally. Serotonin receptors also displayed distinct cellular and developmental expression patterns. HTR1E was confined to the first trimester during highly proliferative stage. HTR4 was enriched for in crypt regions, suggesting a role in proliferation for serotonin. Finally, HTR3E was associated with tuft cells throughout development. Together, these findings reveal the dynamic, cell-type-specific regulation of serotonin in the developing human gut, suggesting its importance in early intestinal development, and provide a framework to study its roles in intestinal development and diseases.
Authors
Long Phan, Lauren Smith, Kristin M. Milano, Weihong Gu, Madison S. Strine, Harvey J. Kliman, Liza Konnikova
Abstract
Testosterone is a key determinant of red blood cell (RBC) biology and susceptibility to hemolysis; however, its contribution to donor-dependent variation in RBC quality and transfusion effectiveness remains unclear. Using data from 2,357 male participants in the NHLBI REDS-III RBC-Omics study, we quantified plasma total testosterone, free testosterone (bioavailable form), and androstenedione and evaluated their associations with donor characteristics, RBC hemolysis, and recipient post-transfusion hemoglobin increments, a clinical measure of RBC transfusion effectiveness. Subphysiological testosterone concentrations were common (~35%) and independently associated with increased storage and osmotic hemolysis. Frequent blood donations were independently associated with lower circulating free testosterone concentrations, even after adjustment for demographic and hematologic factors. Genome-wide association analyses identified loci associated with circulating testosterone, including regions near SHBG, TNFSF12, and the long noncoding RNA BALR6. Several testosterone variants were associated with RBC transfusion effectiveness. Specifically, variants associated with lower testosterone (e.g., TNFSF12) corresponded to higher post-transfusion hemoglobin increments (+9%), whereas BALR6 variants associated with higher testosterone were linked to reduced hemoglobin increments (–40%). In contrast, androstenedione-associated variants were not related to hemolysis or transfusion outcomes. Together, these findings demonstrate that genetic and physiologic variation in testosterone contributes to inter-individual variability in RBC quality and transfusion effectiveness.
Authors
Fang Fang, Nareg Roubinian, Xutao Deng, Cassie Kemmler, Jost Klawitter, Jelena Klawitter, Touraj Shokati, Uwe Christians, Grier P. Page, Tamir Kanias
Abstract
The role of CD8+ T cells in filarial infections remains poorly understood. Given the chronic nature of these infections, individuals living in endemic regions are frequently exposed to other pathogens including viruses. Because CD8 cells are essential for antiviral immunity, understanding how filarial infections shape the cytotoxic compartment is essential to elucidate their impact on bystander immunity. We evaluated the phenotype and function of CD8+ T cells from Loa loa-infected (Fil+) and -uninfected (Fil–) individuals at baseline and following cytomegalovirus (CMV) re-stimulation. Filarial infection was associated with increased activation and proliferation of CD8+ T cells, characterized by elevated expression of Ki-67, CD107a, and production of type 1 and 17 cytokines. Upon CMV re-stimulation, Fil+ individuals showed markedly reduced expansion of antigen-experienced (CD137+) and polyfunctional (CD137+IFN-γ+TNF-α+, CD137+IFN-γ+TNF-α+IL-2+) CD8+ T cells, along with decreased cytotoxic activity. Unbiased clustering analysis revealed markedly reduced frequency of the CD8+CD45RA+CD57+ subset in Fil+ individuals- a population further defined through transcriptomic profiling that showed enrichment for cytolytic gene signatures (GZMB, GNLY, GZMH, CD244, CX3CR1). These results demonstrated that filarial infection is associated with an altered CD8+ T cell profile that is associated with failure to mount effective viral-specific effector responses, including impaired cytokine production and cytotoxic activity.
Authors
Camila Queiroz-Glauss, Justin Lack, Daniel E. Sturdevant, Thomas B. Nutman
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