Speaker: Verónica Martínez-Cerdeño, Associate Professor, Pathology and Laboratory Medicine
Location: Life Sciences Building, Room 1022 (see parking and transportation information below)
Time: Thursday, January 9, 3:10-4:00PM
Title: Cortical interlaminar astrocytes during development and evolution
Astrocytes are one of the main cell types in the cerebral cortex of the brain. Cortical astrocytes are known as protoplasmic and occupy a spherical cortical area where they exert their action. However, another type of astrocyte, the interlaminar astrocyte (ILA), is also present in the cortex. ILA have a soma in layer I, long interlaminar processes running toward deep cortical layers, occupy columnar area, and exert actions across multiple cortical lamina.
ILA were discovered more than 100 years ago, but since then they have received little attention. It is believed that ILA are characteristic of the primate brain, however our studies have indicated that they are common to many mammalian species. We examined the cerebral cortex from 46 species encompassing most orders of therian mammals, including 22 primate species, and discovered that there are two distinct ILA types, that we named “pial ILA” and “subpial ILA”, with specific somatic morphology, position within layer I, and presence across species. We also found that ILA can be “rudimentary ILA” with short processes, or “typical ILA” with longer processes. We found that pial ILA are present in all mammals, while subpial ILA are absent in marsupials, and typical subpial ILA are only found in primates. We confirmed ILA astrocytic nature by investigating their molecular properties and found that while the density of pial ILA somata only varied slightly, the complexity of ILA processes varied greatly across species, reaching the highest values in primates, including human.
ILA were known to be present and develop postnatally, but when exactly they appear during development is not known. We analyzed specific prenatal and postnatal developmental stages of mouse, macaque, chimpanzee and human, and found an increasing ILA morphological complexity throughout development. We provided comprehensive data for primate ILA developmental progression and origin, and how it compares with rudimentary ILA in mouse. We found that ILA are generated prenatally, likely from a late radial glial cell cohort, locally proliferate before gestation ends, and grow interlaminar processes postnatally.
Data obtained from this project will shed light on the ILA role in the evolution and development of the cerebral cortex. We will next unravel the molecular mechanisms responsible for the appearance of ILA in primate and specifically in the human cerebral cortex.
Parking information: The Pavilion Parking Structure is adjacent to the Life Sciences building. The Intercampus Shuttle also runs every hour between the Sacramento Medical Center and the Davis campus and also stops in front of Haring Hall, also adjacent to the Life Sciences building. Please note you must purchase a pass for the shuttle in advance of boarding.