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Katdare KA, Kjar A, O’Brown NM, Neal EH, Sorets AG, Shostak A, Romero-Fernandez W, Kwiatkowski AJ, Mlouk K, Kim H, Cowell RP, Schwensen KR, Horner KB, Wilson JT, Schrag MS, Megason SG, Lippmann ES. IQGAP2 regulates blood-brain barrier immune dynamics. bioRxiv 2024:2023.02.07.527394. [PMID: 38645082 PMCID: PMC11030232 DOI: 10.1101/2023.02.07.527394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Brain endothelial cells (BECs) play an important role in maintaining central nervous system (CNS) homeostasis through blood-brain barrier (BBB) functions. BECs express low baseline levels of adhesion receptors, which limits entry of leukocytes. However, the molecular mediators governing this phenotype remain mostly unclear. Here, we explored how infiltration of immune cells across the BBB is influenced by the scaffold protein IQ motif containing GTPase activating protein 2 (IQGAP2). In mice and zebrafish, we demonstrate that loss of Iqgap2 increases infiltration of peripheral leukocytes into the CNS under homeostatic and inflammatory conditions. Using single-cell RNA sequencing and immunohistology, we further show that BECs from mice lacking Iqgap2 exhibit a profound inflammatory signature, including extensive upregulation of adhesion receptors and antigen-processing machinery. Human tissue analyses also reveal that Alzheimer's disease is associated with reduced hippocampal IQGAP2. Overall, our results implicate IQGAP2 as an essential regulator of BBB immune privilege and immune cell entry into the CNS.
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Affiliation(s)
- Ketaki A. Katdare
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Andrew Kjar
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | | | - Emma H. Neal
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Alexander G. Sorets
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Alena Shostak
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | - Kate Mlouk
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Hyosung Kim
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Rebecca P. Cowell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Katrina R. Schwensen
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Kensley B. Horner
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - John T. Wilson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Matthew S. Schrag
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sean G. Megason
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Ethan S. Lippmann
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Memory and Alzheimer’s Center, Vanderbilt University Medical Center, Nashville, TN, USA
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Brackman LC, Dixon BREA, Bernard M, Revetta F, Cowell RP, Meenderink LM, Washington MK, Piazuelo MB, Algood HMS. IL-17 receptor A functions to help maintain barrier integrity and limit activation of immunopathogenic response to H. pylori infection. Infect Immun 2024; 92:e0029223. [PMID: 38014948 PMCID: PMC10790819 DOI: 10.1128/iai.00292-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/29/2023] [Indexed: 11/29/2023] Open
Abstract
Activation of Th17 cell responses, including the production of IL-17A and IL-21, contributes to host defense and inflammatory responses by coordinating adaptive and innate immune responses. IL-17A and IL-17F signal through a multimeric receptor, which includes the IL-17 receptor A (IL-17RA) subunit and the IL-17RC subunit. IL-17RA is expressed by many cell types, and data from previous studies suggest that loss of IL-17 receptor is required to limit immunopathology in the Helicobacter pylori model of infection. Here, an Il17ra-/- mouse was generated on the FVB/n background, and the role of IL-17 signaling in the maintenance of barrier responses to H. pylori was investigated. Generating the Il17ra-/- on the FVB/n background allowed for the examination of responses in the paragastric lymph node and will allow for future investigation into carcinogenesis. While uninfected Il17ra-/- mice do not develop spontaneous gastritis following H. pylori infection, Il17ra-/- mice develop severe gastric inflammation accompanied by lymphoid follicle production and exacerbated production of Th17 cytokines. Increased inflammation in the tissue, increased IgA levels in the lumen, and reduced production of Muc5ac in the corpus correlate with increased H. pylori-induced paragastric lymph node activation. These data suggest that the cross talk between immune cells and epithelial cells regulates mucin production, IgA production, and translocation, impacting the integrity of the gastric mucosa and therefore activating of the adaptive immune response.
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Affiliation(s)
- Lee C. Brackman
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Beverly R. E. A. Dixon
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Margaret Bernard
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Frank Revetta
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Rebecca P. Cowell
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Leslie M. Meenderink
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - M. Kay Washington
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - M. Blanca Piazuelo
- Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute of Infection, Immunity, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Holly M. Scott Algood
- Division of Infectious Disease, Department of Medicine, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute of Infection, Immunity, and Inflammation (VI4), Vanderbilt University Medical Center, Nashville, Tennessee, USA
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