In this issue, Lyons et al. report that human mutations in the gene encoding the tyrosine kinase receptor EPH receptor B4 (EPHB4) result in venous valve disease. Further, using mouse models, they demonstrate that ephrinB2/EphB4 signaling is required for venous valve development. The cover image shows a large WT mouse venous valve in the femoral vein at postnatal day 6, with staining for smooth muscle α-actin (white), PECAM1 (blue), Foxc2 (green), and Prox1 (red).
BACKGROUND. Childhood cancer survivors who received abdominal radiotherapy (RT) or total body irradiation (TBI) are at increased risk for cardiometabolic disease, but the underlying mechanisms are unknown. We hypothesize that RT-induced adipose tissue dysfunction contributes to the development of cardiometabolic disease in the expanding population of childhood cancer survivors. METHODS. We performed clinical metabolic profiling of adult childhood cancer survivors previously exposed to TBI, abdominal RT, or chemotherapy alone, alongside a group of healthy controls. Study participants underwent abdominal subcutaneous adipose biopsies to obtain tissue for bulk RNA-sequencing. Transcriptional signatures were analyzed using pathway and network analyses and cellular deconvolution. RESULTS. Irradiated adipose tissue is characterized by a gene expression signature indicative of a complex macrophage expansion. This signature includes activation of the TREM2-TYROBP network, a pathway described in diseases of chronic tissue injury. Radiation exposure of adipose is further associated with dysregulated adipokine secretion, specifically a decrease in insulin-sensitizing adiponectin and an increase in insulin resistance-promoting plasminogen activator inhibitor-1. Accordingly, survivors exhibiting these changes have early signs of clinical metabolic derangement such as increased fasting glucose and hemoglobin A1c. CONCLUSION. Childhood cancer survivors exposed to abdominal RT or TBI during treatment exhibit signs of chronic subcutaneous adipose tissue dysfunction, manifested as dysregulated adipokine secretion that may negatively impact their systemic metabolic health. FUNDING. Rockefeller University Hospital; National Institute of General Medical Sciences (T32GM007739); National Center for Advancing Translational Sciences (UL1TR001866); National Cancer Institute (P30CA008748); American Cancer Society (133831-CSDG-19-117-01-CPHPS); American Diabetes Association (1-17-ACE-17); anonymous donor (Memorial Sloan Kettering Cancer Center).
Xiaojing Huang, Olivia A. Maguire, Jeanne M. Walker, Caroline S. Jiang, Thomas S. Carroll, Ji-Dung Luo, Emily Tonorezos, Danielle Novetsky Friedman, Paul Cohen
Fibrotic posterior capsular opacification (PCO), a major complication of cataract surgery, is driven by transforming growth factor β (TGFβ). Previously, αV integrins were found to be critical for the onset of TGFβ-mediated PCO in vivo, however, the functional heterodimer was unknown. Here, β8 integrin conditional knockout (β8ITGcKO) lens cells (LCs) were observed to attenuate their fibrotic responses, while both β5 and β6 integrin null LCs underwent fibrotic changes similar to WT at 5 days PCS. RNAseq revealed that β8ITGcKO LCs attenuated their upregulation of integrins and their ligands, as well as known targets of TGFβ induced signaling at 24 hours PCS. Treatment of β8ITGcKO eyes with active TGFβ1 at the time of surgery rescued the fibrotic response. Treatment of wild type mice with an anti- αVβ8 integrin function blocking antibody at the time of surgery ameliorated both canonical TGFβ signaling and LC fibrotic response PCS, and treatment at 5 days PCS, after surgically induced fibrotic responses are established, largely reversed this fibrotic response. These data suggest that αVβ8 integrin is a major regulator of TGFβ activation by LCs PCS and that therapeutics targeting αVβ8 integrin could be effective for fibrotic PCO prevention and treatment.
Mahbubul H. Shihan, Samuel G. Novo, Yan Wang, Dean Sheppard, Amha Atakilit, Thomas D. Arnold, Nicole M. Rossi, Adam P. Faranda, Melinda K. Duncan
Cytokine-producing CD4+ T cells play a crucial role in the control of Mycobacterium tuberculosis (Mtb) infection; however, there is a delayed appearance of effector T cells in the lungs following aerosol infection. The immunomodulatory cytokine IL-10 antagonizes control of Mtb infection through mechanisms associated with reduced CD4+ T cell responses. Here, we show that IL-10 overexpression only before the onset of the T cell response impairs control of Mtb growth. During chronic infection, IL-10 overexpression reduces the CD4+ T cell response without impacting the outcome of infection. IL-10 overexpression early during infection did not significantly impair the kinetics of CD4+ T cell priming and effector differentiation; however, CD4+ T cells primed and differentiated in a IL-10-enriched environment display reduced expression of CXCR3 and do not migrate into the lung parenchyma thereby limiting their ability to control infection. Importantly, these CD4+ T cells maintain their vasculature phenotype and are unable to control infection even after adoptively transferred into low IL-10 settings. Together our data support a model wherein, during Mtb infection, IL-10 acts intrinsically on T cells impairing their parenchymal migratory capacity and ability to engage with infected phagocytic cells thereby impeding control of infection.
Catarina M. Ferreira, Ana Margarida Barbosa, Palmira Barreira-Silva, Ricardo Silvestre, Cristina Cunha, Agostinho Carvalho, Fernando Rodrigues, Margarida Correia-Neves, António G. Castro, Egídio Torrado
Interleukin-33 (IL-33), a nuclear alarmin released during cell death, exerts context-specific effects on adaptive and innate immune cells eliciting potent inflammatory responses. We screened blood, skin and kidney tissues from patients with Systemic Lupus Erythematosus (SLE), a systemic autoimmune disease driven by unabated type I interferon (IFN) production, and found increased amounts of extracellular IL-33 complexed with Neutrophil Extracellular Traps (NETs), correlating with severe, active disease. Using a combination of molecular, imaging and proteomic approaches, we show that SLE neutrophils -activated by disease immunocomplexes- release IL-33-decorated NETs that stimulate robust IFNα synthesis by plasmacytoid dendritic cells (pDCs) in an IL-33-receptor (ST2L)-dependent manner. IL33-silenced neutrophil-like cells cultured under lupus-inducing conditions generated NETs with diminished interferogenic effect. Importantly, SLE patient-derived NETs are enriched in mature bioactive isoforms of IL-33 processed by the neutrophil proteases elastase and cathepsin G. Pharmacological inhibition of these proteases neutralized IL-33-dependent IFNα production elicited by NETs. These data demonstrate a novel role for cleaved IL-33 alarmin decorating NETs in human SLE, linking neutrophil activation, type I IFN production and end-organ inflammation with skin pathology mirroring that observed in the kidneys.
Spiros Georgakis, Katerina Gkirtzimanaki, Garyfalia Papadaki, Hariklia Gakiopoulou, Elias Drakos, Maija-Leena Eloranta, Manousos Makridakis, Georgia Kontostathi, Jerome Zoidakis, Eirini Baira, Lars Rönnblom, Dimitrios T. Boumpas, Prodromos Sidiropoulos, Panayotis Verginis, George Bertsias
Ozone is a highly reactive environmental pollutant with well-recognized adverse effects on lung health. Bronchial hyperactivity (BHR) is one consequence of ozone exposure, particularly for individuals with underlying lung disease. Our data demonstrate ozone induces substantial ATP release from human airway epithelia in vitro and into the airways of mice in vivo, and that ATP is a potent inducer of mast cell degranulation and BHR, acting through P2X7 receptors on mast cells. Both mast cell-deficient and P2X7 receptor-deficient (P2XT-/-) mice demonstrate markedly attenuated BHR to ozone. Re-constitution of mast cell-deficient mice with WT mast cells and P2X7-/- mast cells restores ozone-induced BHR. Despite equal numbers of mast cells in reconstituted mouse lungs, mice reconstituted with P2X7-/- mast cells demonstrated significantly less robust BHR than mice reconstituted with WT mast cells. These results support a model where P2X7 on both mast cells and other cell types contribute to ozone-induce BHR.
Xiaomei Kong, William C. Bennett, Corey M. Jania, Kelly D. Chason, Zachary German, Jennifer Adouli, Samuel D. Budney, Brandon T. Oby, Catharina van Heusden, Eduardo R. Lazarowski, Ilona Jaspers, Scott H. Randell, Barry A. Hedgespeth, Glenn Cruse, Xiaoyang Hua, Stephen A. Schworer, Gregory J. Smith, Samir N. P. Kelada, Stephen L. Tilley
JCI This Month is a digest of the research, reviews, and other features published each month.