Endothelial Specific Deletion of Autotaxin Improves Stroke Outcomes

Autotaxin (ATX) is an extracellular secretory enzyme (lysophospholipase D) that catalyzes the hydrolysis of lysophosphatidyl choline to lysophosphatidic acid (LPA). The ATX-LPA axis is a well-known pathological mediator of liver fibrosis, metastasis in cancer, pulmonary fibrosis, atherosclerosis, and neurodegenerative diseases. Also, it is believed that LPA may cause vascular permeability. In ischemic stroke, vascular permeability leading to hemorrhagic transformation is a major limitation for therapies and an obstacle to stroke management. So, in this study, we generated an endothelial-specific ATX deletion in mice (ERT2 ATX-/-) to observe stroke outcomes in a mouse stroke model to analyze the role of endothelial ATX. The AR2 probe and Evans Blue staining were used to perform the ATX activity and vascular permeability assays, respectively. Laser speckle imaging was used to observe the cerebral blood flow following stroke. In this study, we observed that stroke outcomes were alleviated with endothelial deletion of ATX. Permeability and infarct volume was reduced in ERT2 ATX-/- mice compared to ischemia-reperfusion (I/R) only mice. In addition, cerebral blood flow was retained in ERT2 ATX-/- compared to I/R mice. The outcomes in the stroke model are alleviated due to limited LPA concentration, reduced ATX concentration, and ATX activity in ERT2 ATX-/- mice. In this study, we observed that ATX produced by the endothelium could be a major factor responsible for increases in permeability and infarcts, and adverse effects on the cerebral blood flow during cerebral ischemic reperfusion. LPA produced specifically by endothelial cells in the vasculature can disrupt the BBB leading ultimately to neuronal loss and glial activation. With the deletion of ATX from the endothelium, the microvasculature might be more resilient due to reduced LPA. We found evidence that the functional outcomes of ischemic stroke were alleviated with ATX deletion. Therefore, endothelial ATX can be targeted to make better and more effective therapies for stroke management. his research was supported by Louisiana State University Health Sciences-Shreveport Intramural Grant 110101074A to SM; National Institutes of Health grants HL141998 and HL141998-01S1 to SM; grants AA025744, AA026708, and AA025744-02S1 to MP; grants HL122354 and HL145753 to MSB; P20GM12130 to Dr. Christopher Kevil. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.