The brain is the most vascularized organ in the mammalian body, with its complex network of blood vessels interacting with neurons and glia in multicellular complexes termed neurovascular units. Growth factors and extracellular matrix (ECM) proteins coordinately regulate adhesion and signaling between neural cells and vascular cells to promote normal brain development and physiology. These events are deregulated in many brain pathologies, including developmental disorders such as germinal matrix hemorrhage and age-related neurocognitive deficits such as Vascular Dementia. We understand surprisingly little about mechanisms that regulate normal neural-vascular cell contact and communication or how these events go awry during disease pathogenesis. Here, we will analyze roles for ECM proteins and their integrin receptors in neurovascular biology and disease. Integrins are a-b heterodimeric proteins that link ECM ligands to the cytoskeleton and control intracellular signaling cascades. While a great deal is known about adhesion and signaling functions for most integrins, the pathways controlled by integrin avb8, which was discovered more than 25 years ago, remain largely unexplored. avb8 is expressed in glial cells of the central nervous system (CNS) and plays critical roles in regulating vascular endothelial cell behaviors via activation of ECM-bound latent-transforming growth factor b (TGFb) protein ligands. In this renewal project, we will develop genetically engineered mouse models and primary cell culture systems to analyze avb8 integrin-mediated adhesion and signaling pathways in neurovascular unit pathophysiology. First, we will characterize a newly developed knock-in mouse model that enables dissection of avb8 integrin extracellular adhesion from intracellular signaling in neural-vascular cell contact and communication. In particular, we will study integrin-dependent blood vessel morphogenesis and endothelial barrier formation in the brain and retina. Second, we will determine functions for the b8 cytoplasmic domain in regulating integrin inside-out activation and ECM affinity/avidity using biochemical assays and primary cell culture models. Third, we will explore paracrine signaling between avb8 integrin in perivascular glial cells and TGFb receptors in endothelial cells. A particular focus will be placed on integrin-dependent regulation of the docosahexaenoic (DHA) transporter Mfsd2a in CNS endothelial cells. Fourth, we will explore links between defective DHA metabolism and BBB dysfunction in the progressive neurodegenerative pathologies that develop in integrin mutant mice. In summary, experiments in this project will reveal new and important mechanisms underlying integrin control of neurovascular development and physiology. The mutant mouse models may also provide valuable insights into pathways involved in the pathogenesis of vascular-related neurological diseases.

Public Health Relevance

In this project, we will analyze adhesion and signaling cascades regulated by integrins and determine how they promote blood vessel development in the brain and retina. We will also study how genetically targeting components of these pathways lead to vascular pathologies. !

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS087635-07
Application #
10064016
Study Section
Cellular and Molecular Biology of Glia Study Section (CMBG)
Program Officer
Koenig, James I
Project Start
2014-08-15
Project End
2024-11-30
Budget Start
2020-12-01
Budget End
2021-11-30
Support Year
7
Fiscal Year
2021
Total Cost
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Neurosurgery
Type
Hospitals
DUNS #
800772139
City
Houston
State
TX
Country
United States
Zip Code
77030
Chen, Zhihua; Morales, John E; Guerrero, Paola A et al. (2018) PTPN12/PTP-PEST Regulates Phosphorylation-Dependent Ubiquitination and Stability of Focal Adhesion Substrates in Invasive Glioblastoma Cells. Cancer Res 78:3809-3822
Guerrero, P A; Tchaicha, J H; Chen, Z et al. (2017) Glioblastoma stem cells exploit the ?v?8 integrin-TGF?1 signaling axis to drive tumor initiation and progression. Oncogene 36:6568-6580
Toutounchian, Jordan J; McCarty, Joseph H (2017) Selective expression of eGFP in mouse perivascular astrocytes by modification of the Mlc1 gene using T2A-based ribosome skipping. Genesis 55:
Cheerathodi, Mujeeburahiman; Avci, Naze G; Guerrero, Paola A et al. (2016) The Cytoskeletal Adapter Protein Spinophilin Regulates Invadopodia Dynamics and Tumor Cell Invasion in Glioblastoma. Mol Cancer Res 14:1277-1287
Lee, Hye Shin; Cheerathodi, Mujeeburahiman; Chaki, Sankar P et al. (2015) Protein tyrosine phosphatase-PEST and ?8 integrin regulate spatiotemporal patterns of RhoGDI1 activation in migrating cells. Mol Cell Biol 35:1401-13
Hirota, Shinya; Clements, Thomas P; Tang, Leung K et al. (2015) Neuropilin 1 balances ?8 integrin-activated TGF? signaling to control sprouting angiogenesis in the brain. Development 142:4363-73
Zhang, Lin; Zhang, Siyuan; Yao, Jun et al. (2015) Microenvironment-induced PTEN loss by exosomal microRNA primes brain metastasis outgrowth. Nature 527:100-104
Lee, Hye Shin; McCarty, Joseph H (2014) Inducible gene deletion in glial cells to study angiogenesis in the central nervous system. Methods Mol Biol 1135:261-74