Graduation Year

2023

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Medical Sciences

Major Professor

Yao Yao, Ph.D.

Committee Member

Jerome Breslin, Ph.D.

Committee Member

Lianchun Wang, M.D.

Committee Member

Laura J. Blair, Ph.D.

Keywords

Blood-brain Barrier, Basement Membrane, Transcytosis, Myelination

Abstract

Oligodendrocyte lineage is a glial cell population in the central nervous system. The lineage starts with oligodendrocyte precursor cells, which differentiate and mature into mature oligodendrocytes. Myelination, the major function of mature oligodendrocytes, plays a significant role for normal function of the central nervous system, and its dysfunction leads to many demyelinating diseases, such as multiple sclerosis. During the lineage progression, an extracellular matrix protein, laminin, actively regulates the cells' biology, including cell proliferation, differentiation, and myelination. However, the cellular sources of the laminin that controls oligodendrocyte lineage cells remain largely unknown. Interestingly, previous studies have shown that oligodendrocyte lineage cells themselves make different laminin chains.

To investigate the functions of oligodendrocyte lineage-derived laminins, our laboratory has generated multiple conditional knockout mouse lines that target different chains of oligodendrocyte lineage-derived laminin (α5 and γ1 chains). Using the laminin γ1 knockout mouse line, we found that oligodendrocyte lineage-derived laminin γ1 is crucial for maintaining blood-brain barrier integrity through inhibiting transcytosis across endothelial cells. Furthermore, we found that oligodendrocyte lineage-derived laminin γ1 promotes proliferation, differentiation, and myelination of oligodendrocyte lineage cells. In sharp contrast, our study using the laminin α5 knockout mouse lines revealed that oligodendrocyte lineage-derived laminin α5 is dispensable for blood-brain barrier integrity maintenance and oligodendrocyte lineage biology under homeostatic and intracerebral stroke conditions.

Chapter 1 and Chapter 2 of this dissertation include a literature review of the roles of laminin in regulating oligodendrocyte biology and our experimental work that demonstrates the important functions of oligodendrocyte lineage-derived laminin γ1 for blood-brain barrier integrity maintenance and oligodendrocyte lineage biology. Chapter 3 and Chapter 4 include a literature review of oligodendrocyte biology under intracerebral hemorrhagic stroke conditions and our experimental work that shows the dispensable roles of oligodendrocyte lineage-derived laminin α5 under homeostatic and intracerebral hemorrhage conditions. Lastly Chapter 5 includes a literature review of how basement membrane components change in ischemic stroke, suggesting an area of future work for oligodendrocyte lineage-derived laminins. Together, this dissertation provides valuable insight to the fields of oligodendrocyte and laminin biology by unveiling the functions of oligodendrocyte lineage-derived laminins.

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Neurosciences Commons

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