My long-term goal is to elucidate mechanisms for glial development. The focus of this application is to characterize local proliferation of astrocytes in the cerebral cortex and the mechanism underlying their interaction with blood vessels at the postnatal stage. During postnatal weeks 2 and 3, the density of blood vessels and the number of glial cells both increase by ~4 fold in the rodent brain. It is still unclear where the large number of astrocytes come from and how they interact with blood vessels. My preliminary data show that postnatal local proliferation of astrocytes is widely distributed in different layers of the cerebral cortex, and these astrocytes retain their endfeet (perivascular processes of astrocytes) with blood vessels while they enter mitotic stages. I thus hypothesize that local prolifaration of astrocytes is a main source of cortical astrocytes that contribute to endfoot formation in the postnatal brain. To address the hypothesis, I propose two specific aims: (1) Characterize local proliferation of astrocytes and their fate and function in the cerebral cortex;(2) Elucidate the mechanism underlying endfoot formation around blood vessels mediated by locally generated astrocytes. I have established two groups of transgenic mouse lines to sparsely label astrocytes via genetically encoded fluorescent markers with unprecedented resolution, along with methods I developed to label and record dividing cells. I am therefore uniquely poised to undertake this novel study. Research proposed in the K99 Mentored phase (year 1 and 2) is concentrated on the establishment of methods for retroviral labeling and imaging of glial proliferation in live animals, which will be carried out with the supervision of Dr. Lily Jan. The R00 Independent phase (years 3 to 5) will focus on characterizing the function of astrocytes generated via local proliferation, and the mechanism underlying their interaction with blood vessels. The proposed research is innovative because it will provide the first direct evidence of postnatal local proliferation of astrocytes in cerebral cortex and show how they integrate into glial network and form endfoot structures with blood vessels.

Public Health Relevance

The outcomes of these experiments will greatly improve our understanding of a variety of neurological diseases such as ischemic stroke and brain tumors caused by dysfunction of glial-vascular interaction or uncontrolled glial proliferation. Elucidation of the mechanism of formation of glial-vascular interaction will further facilitate development of new therapeutic targets for the treatment of these neurological diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Career Transition Award (K99)
Project #
1K99NS073735-01
Application #
8090244
Study Section
NST-2 Subcommittee (NST)
Program Officer
Jacobs, Tom P
Project Start
2011-06-01
Project End
2013-05-31
Budget Start
2011-06-01
Budget End
2012-05-31
Support Year
1
Fiscal Year
2011
Total Cost
$77,678
Indirect Cost
Name
University of California San Francisco
Department
Physiology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Jia, Jie-Min; Chowdary, Praveen D; Gao, Xiaofei et al. (2017) Control of cerebral ischemia with magnetic nanoparticles. Nat Methods 14:160-166
Ge, W-P; Jia, J-M (2016) Local production of astrocytes in the cerebral cortex. Neuroscience 323:3-9
Ge, Woo-Ping; Miyawaki, Atsushi; Gage, Fred H et al. (2012) Local generation of glia is a major astrocyte source in postnatal cortex. Nature 484:376-80