. PATHOGNESIS OF CEREBRAL ISCHEMIA: The discovery of ET-1 and NO has greatly contributed to our understanding of the functional changes of many organs under physiological and pathological conditions (e.g., hypertension, atherosclerosis, and stroke). Previous studies focused on interactions of endocannabinoids [2-arachidonoylglycerol (2-AG) and anandamide (ANA) with the vasoconstrictor, endothelin-1 (ET-1). Both 2-AG and ANA are produced in various organs (brain,gut) and cell [monocytes, platelets, endothelial cells (EC)]; they elicit neuromodulator, cytoprotective (i.e., brain ischemia and trauma) and cardiovascular including vasodilatory effects, which are mainly mediated through cannabinoid (CB) receptors CB1, CB2 receptors. 2-AG antioxidant properties have also been implicated to ameliorate BBB injury and edema formation induced by closed head injury (CHI). This supposition was confirmed by the observed 2-AG modulation of brain injury, BBB permeability and edema formation after CHI. In addition comparable effects between 2-AG and 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl(TPL), a known antioxidant nitroxide on human brain endothelial Ca2+ and cytoskeletal responses to H2O2 (ROS) where investigated in vitro. Both substances were shown to similarly modify endothelial responses mentioned above substantiating the implicated 2-AG antioxidant properties. Latest reports indicate that the vasodilatory effects of ANA in contrast to 2-AG is mediated through the vanilloid TRPV1 receptor. Untill now most of the endothelial-dependent and endothelial-dependent vascular responses have been shown to be mediated by CB1 receptors. In view of these observations, we hypothesize a possible endothelial existence of TRPV1 receptors along with CB1 and CB2 receptors and their involvement in human brain endothelial cells (HBEC) responses to endocannabinoids and related substances. These studies led to the first clear demonstration of the constitutive expression of TRPV1, CB1, and CB2, receptors (mRNA and protein)on HBEC. It also provided evidence that these receptors are functional and possibly cooperative in these cells. In addition the results demonstrated that 2-AG acts as a ligand for TRPV1 receptors as well as for cannabinoid receptors. The novel findings of colocalization and functional capacities of TRPV1, CB1, and CB2, receptors on HBEC strongly suggest that these receptors may affect the function of cerebral microvascular endothelium and contribute to the regulation of cerebral blood flow and BBB permeability. In vivo studies in progress are designated to confirm this contention. II. TOLERANCE TO CEREBRAL ISCHEMIA: The study of SHR-SP tolerization with E-selectin (in collaboration with Dr. J. Hallenbeck) demonstrated a reduced incidence and size of brain infarct and hemorrhage. The latest studies demonstrated that mucosal tolerization renders cell-mediated protection against cerebral damage (stroke). Continued investigation is focused on the mechamism involved in the observed above mentioned phenomena tolerized SHR-SP animals as compared to the Naive rats and whether the E-selectin-induced tolerization against brain injury in SHR-SP rats also effect peripheral organs (i.e., heart and kidneys). In addition, a new initiative for stroke prevention (induction of mucosal tolerance to E-selectin) involves a preclinical study with spontaneously hypertensive, genetically stroke-prone rats and an approved Phase II A Clinical Trial

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Intramural Research (Z01)
Project #
1Z01NS002933-08
Application #
6990669
Study Section
Surgery and Bioengineering Study Section (SB)
Project Start
Project End
Budget Start
Budget End
Support Year
8
Fiscal Year
2004
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Golech, Susanne Andrea; McCarron, Richard M; Chen, Ye et al. (2004) Human brain endothelium: coexpression and function of vanilloid and endocannabinoid receptors. Brain Res Mol Brain Res 132:87-92
Takeda, H; Spatz, M; Ruetzler, C et al. (2004) Induction of mucosal tolerance to E-selectin targets immunomodulation to activating vessel segments and prevents ischemic and hemorrhagic stroke. Ernst Schering Res Found Workshop :117-32
Chen, Y; McCarron, R M; Golech, S et al. (2003) ET-1- and NO-mediated signal transduction pathway in human brain capillary endothelial cells. Am J Physiol Cell Physiol 284:C243-9
Chen, Yong; Ruetzler, Christl; Pandipati, Sruthi et al. (2003) Mucosal tolerance to E-selectin provides cell-mediated protection against ischemic brain injury. Proc Natl Acad Sci U S A 100:15107-12
Yu, Zhao-Ying; Ono, Shinsuke; Spatz, Maria et al. (2002) Effect of hemorrhagic shock on apoptosis and energy-dependent efflux system in the brain. Neurochem Res 27:1625-32
Chen, Y; McCarron, R M; Ohara, Y et al. (2000) Human brain capillary endothelium: 2-arachidonoglycerol (endocannabinoid) interacts with endothelin-1. Circ Res 87:323-7
Liu, J; Ginis, I; Spatz, M et al. (2000) Hypoxic preconditioning protects cultured neurons against hypoxic stress via TNF-alpha and ceramide. Am J Physiol Cell Physiol 278:C144-53
Ginis, I; Schweizer, U; Brenner, M et al. (1999) TNF-alpha pretreatment prevents subsequent activation of cultured brain cells with TNF-alpha and hypoxia via ceramide. Am J Physiol 276:C1171-83
Dawson, D A; Sugano, H; McCarron, R M et al. (1999) Endothelin receptor antagonist preserves microvascular perfusion and reduces ischemic brain damage following permanent focal ischemia. Neurochem Res 24:1499-505