To Explore the Potential Role of Exosomes as a Biomarker in Cerebral Ischemia

Exosomes are nanometer-sized vesicles released from cells into the blood, where they can transmit signals throughout the body. These vesicles contain materials that reflect the genetic and proteomic content of the secreting cell. With these characters, exosomes may serve as a platform for the development of biomarker especially for neurological diseases because brain component is inaccessible in the conventional approach. The objective of this proposal is to define the potential role of exosomes as a biomarker in cerebral ischemia. It was known that excessive reactive oxygen species (ROS) generation can induce the functional and structural damage to neuronal cells and may play a significant role in the pathophysiology of cerebral ischemia. It was also acknowledged that ischemic neuronal damage is mainly due to an inflammatory pathogenesis. Endogenous protective mechanisms including anti-oxidation, anti-inflammation, and DNA repair machinery may be elicited to counteract these detrimental effects. We hypothesize that cerebral ischemia-induced neuronal damage may relate to excessive ROS formation and inflammatory response, which may activate endogenous protective mechanism including anti-oxidation, anti-inflammation and DNA repair machinery and exosomes containing these molecules can be detected from peripheral blood. We also hypothesize that neuroprotection agents including pioglitazone, rosuvastatin, and minocycline may affect exosomes secretion and regulate anti-oxidation, anti-inflammation and DNA repair machinery in exosomes and lessen ROS or inflammatory-induced neuronal injury. These will be accomplished by using three-vessel occlusion model (bilateral common carotid artery and right middle cerebral artery) of focal cerebral ischemia, Western blotting, immunohistochemical study, measuring protein carbonyl and malondialdehyde content, 8-OHdG detection, and qualitative and quantitative analysis of DNA damage on both side cortices and between vehicle and treatment group. Exosomes will be collected from peripheral blood and verified for particle size both by electron microscopy (EM) and Nanoparticle Tracking Analysis and by western blotting for the exosomes marker identification such as tetraspanins, TSG101, and Alix. For extraction of neural-derived exosome from whole exosomes, each exosomes suspension will be incubated with anti-neural cell adhesion molecule-1 (NCAM-1) or anti-neural cell adhesion molecule L1 (L1CAM) antibodies and protein from these neural-derived exosomes will be extracted to analyze. Information from these neural-derived exosomes will offer more insight about molecules at work to exert protective effect during ischemic condition. Overall, a potential biomarker involving both detrimental pathway or protective mechanism under cerebral ischemia may be obtained from the proposed studies. The present proposal, if accomplished, may provide new information through exosomes from peripheral blood sampling regarding the redox status and inflammatory condition in cerebral ischemia-related neuronal damage that may endow a rationale using or developing new therapeutic regimens for cerebral ischemia.

Project ID:PC10507-0260
External Project ID:MOST105-2314-B182-003