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Kovacs MA, Babcock IW, Royo Marco A, Sibley LA, Kelly AG, Harris TH. Vascular Endothelial Growth Factor-C Treatment Enhances Cerebrospinal Fluid Outflow during Toxoplasma gondii Brain Infection but Does Not Improve Cerebral Edema. Am J Pathol 2024; 194:225-237. [PMID: 38065361 PMCID: PMC10835445 DOI: 10.1016/j.ajpath.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 10/02/2023] [Accepted: 11/06/2023] [Indexed: 01/22/2024]
Abstract
Cerebral edema frequently develops in the setting of brain infection and can contribute to elevated intracranial pressure, a medical emergency. How excess fluid is cleared from the brain is not well understood. Previous studies have shown that interstitial fluid is transported out of the brain along perivascular channels that collect into the cerebrospinal fluid (CSF)-filled subarachnoid space. CSF is then removed from the central nervous system through venous and lymphatic routes. The current study tested the hypothesis that increasing lymphatic drainage of CSF would promote clearance of cerebral edema fluid during infection with the neurotropic parasite Toxoplasma gondii. Fluorescent microscopy and magnetic resonance imaging was used to show that C57BL/6 mice develop vasogenic edema 4 to 5 weeks after infection with T. gondii. Tracer experiments were used to evaluate how brain infection affects meningeal lymphatic function, which demonstrated a decreased rate in CSF outflow in T. gondii-infected mice. Next, mice were treated with a vascular endothelial growth factor (VEGF)-C-expressing viral vector, which induced meningeal lymphangiogenesis and improved CSF outflow in chronically infected mice. No difference in cerebral edema was observed between mice that received VEGF-C and those that rececived sham treatment. Therefore, although VEGF-C treatment can improve lymphatic outflow in mice infected with T. gondii, this effect does not lead to increased clearance of edema fluid from the brains of these mice.
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Affiliation(s)
- Michael A Kovacs
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Isaac W Babcock
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Ana Royo Marco
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Lydia A Sibley
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Abigail G Kelly
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Tajie H Harris
- Center for Brain Immunology and Glia, Department of Neuroscience, University of Virginia, Charlottesville, Virginia.
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Iker Etchegaray J, Kelley S, Penberthy K, Karvelyte L, Nagasaka Y, Gasperino S, Paul S, Seshadri V, Raymond M, Marco AR, Pinney J, Stremska M, Barron B, Lucas C, Wase N, Fan Y, Unanue E, Kundu B, Burstyn-Cohen T, Perry J, Ambati J, Ravichandran KS. Phagocytosis in the retina promotes local insulin production in the eye. Nat Metab 2023; 5:207-218. [PMID: 36732622 PMCID: PMC10457724 DOI: 10.1038/s42255-022-00728-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 12/16/2022] [Indexed: 02/04/2023]
Abstract
The retina is highly metabolically active, relying on glucose uptake and aerobic glycolysis. Situated in close contact to photoreceptors, a key function of cells in the retinal pigment epithelium (RPE) is phagocytosis of damaged photoreceptor outer segments (POS). Here we identify RPE as a local source of insulin in the eye that is stimulated by POS phagocytosis. We show that Ins2 messenger RNA and insulin protein are produced by RPE cells and that this production correlates with RPE phagocytosis of POS. Genetic deletion of phagocytic receptors ('loss of function') reduces Ins2, whereas increasing the levels of the phagocytic receptor MerTK ('gain of function') increases Ins2 production in male mice. Contrary to pancreas-derived systemic insulin, RPE-derived local insulin is stimulated during starvation, which also increases RPE phagocytosis. Global or RPE-specific Ins2 gene deletion decreases retinal glucose uptake in starved male mice, dysregulates retinal physiology, causes defects in phototransduction and exacerbates photoreceptor loss in a mouse model of retinitis pigmentosa. Collectively, these data identify RPE cells as a phagocytosis-induced local source of insulin in the retina, with the potential to influence retinal physiology and disease.
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Affiliation(s)
- J Iker Etchegaray
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Shannon Kelley
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kristen Penberthy
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Laura Karvelyte
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yosuke Nagasaka
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
| | - Sofia Gasperino
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Soumen Paul
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Vikram Seshadri
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Michael Raymond
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Ana Royo Marco
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Jonathan Pinney
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Stremska
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brady Barron
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Christopher Lucas
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- University of Edinburgh, Edinburgh, UK
| | - Nishikant Wase
- Biomolecular Analysis Facility, University of Virginia, Charlottesville, VA, USA
| | - Yong Fan
- Drexel University, Philadelphia, PA, USA
| | - Emil Unanue
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Bijoy Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Tal Burstyn-Cohen
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Justin Perry
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jayakrishna Ambati
- Center for Advanced Vision Science, University of Virginia, Charlottesville, VA, USA
- Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA.
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.
- Hadassah Medical School, Hebrew University of Jerusalem, Jerusalem, Israel.
- VIB/UGent Inflammation Research Centre, and Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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Bolte AC, Shapiro DA, Dutta AB, Ma WF, Bruch KR, Kovacs MA, Royo Marco A, Ennerfelt HE, Lukens JR. The meningeal transcriptional response to traumatic brain injury and aging. eLife 2023; 12:81154. [PMID: 36594818 PMCID: PMC9810333 DOI: 10.7554/elife.81154] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/14/2022] [Indexed: 12/31/2022] Open
Abstract
Emerging evidence suggests that the meningeal compartment plays instrumental roles in various neurological disorders, however, we still lack fundamental knowledge about meningeal biology. Here, we utilized high-throughput RNA sequencing (RNA-seq) techniques to investigate the transcriptional response of the meninges to traumatic brain injury (TBI) and aging in the sub-acute and chronic time frames. Using single-cell RNA sequencing (scRNA-seq), we first explored how mild TBI affects the cellular and transcriptional landscape in the meninges in young mice at one-week post-injury. Then, using bulk RNA-seq, we assessed the differential long-term outcomes between young and aged mice following TBI. In our scRNA-seq studies, we highlight injury-related changes in differential gene expression seen in major meningeal cell populations including macrophages, fibroblasts, and adaptive immune cells. We found that TBI leads to an upregulation of type I interferon (IFN) signature genes in macrophages and a controlled upregulation of inflammatory-related genes in the fibroblast and adaptive immune cell populations. For reasons that remain poorly understood, even mild injuries in the elderly can lead to cognitive decline and devastating neuropathology. To better understand the differential outcomes between the young and the elderly following brain injury, we performed bulk RNA-seq on young and aged meninges 1.5 months after TBI. Notably, we found that aging alone induced upregulation of meningeal genes involved in antibody production by B cells and type I IFN signaling. Following injury, the meningeal transcriptome had largely returned to its pre-injury signature in young mice. In stark contrast, aged TBI mice still exhibited upregulation of immune-related genes and downregulation of genes involved in extracellular matrix remodeling. Overall, these findings illustrate the dynamic transcriptional response of the meninges to mild head trauma in youth and aging.
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Affiliation(s)
- Ashley C Bolte
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Daniel A Shapiro
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - Arun B Dutta
- Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Department of Biochemistry and Molecular Genetics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Wei Feng Ma
- Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Center for Public Health Genomics, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Katherine R Bruch
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - Michael A Kovacs
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Ana Royo Marco
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of MedicineCharlottesvilleUnited States
| | - Hannah E Ennerfelt
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States
| | - John R Lukens
- Department of Neuroscience, Center for Brain Immunology and Glia (BIG), University of Virginia School of MedicineCharlottesvilleUnited States,Medical Scientist Training Program, University of Virginia School of MedicineCharlottesvilleUnited States,Immunology Training Program, University of Virginia School of MedicineCharlottesvilleUnited States
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