Cocultures of meningeal and astrocytic cells—A model for the formation of the glial‐limiting membrane

Abstract

The glial-limiting membrane at the border of the central nervous system (CNS) consists of glial endfeet covered by a basal lamina. The formation of the glia limitans seems to be controlled by adjacent meninges but only little is known about this interaction. In the present study astrocytes and meningeal cells were investigated in vitro to see if cocultures of these cells can serve as a suitable model for the differentiation of the glial-limiting membrane and can be used to define the conditions under which the glial-limiting membrane develops. The following observations were made in cocultures of meningeal and astrocytic cells of two-day-old rats: (i) epithelioid astrocytes were transformed into stellate cells; (ii) single colonies of proliferating epithelioid astrocytes were generated; (iii) the area around these colonies becomes devoid of meningeal cells, which seem to form a circular border around the astroglial islands; (iv) from the glial colonies long thin glial processes grow towards the surrounding meningeal cells, terminating at the site of contact; (v) in the contact zone between meningeal cells and astrocytes irregular shaped deposits of electron dense material resembling a basal lamina were seen. These observations indicate that indeed a structure resembling a glial-limiting membrane develops in cocultures of meningeal and astrocytic cells. Its formation depends on the balance of growth promoting effects of meningeal cells on astrocytes and growth inhibiting effects of astrocytes on meningeal cells. Both activities can be enriched from conditioned media of pure astrocytic or meningeal cell culture. The proposed model of meningo-astrocytic cocultures may be a helpful instrument for further investigations on the formation of the glia limitans.

The astrocyte/meningeal cell interface – a barrier to successful nerve regeneration?

“…In vitro model of the astrocyte/meningeal interface Abnet et al (1991), Struckhoff (1995) and Hirsch and Bahr (1999) have all shown that when primary astrocytes and meningeal cells are grown in culture together the two cell types show little mixing and a glia limitans-like structure forms at the point where the different cell types meet. Similarly when we co-cultured aggregates of primary cells we found that when they spread out and formed a monolayer a distinct morphology could be observed -a patchwork pattern was formed with the different cell types growing adjacent to one another and yet not combining.…”

Lipopolysaccharide Up-regulates IL-6Rα Expression in Cultured Leptomeningeal Cells via Activation of ERK1/2 Pathway

“…The cell bodies were small in size with two or more short slender processes. The identity of the cells was further confirmed by immunocytochemical staining of Thy1.1, a marker used for labeling leptomeningeal cells in other study [31] (Fig. 1c).…”

“…Leptomeningeal cells were harvested from newborn SD rats, as described previously [31], with minor modification. The meninges were carefully removed and dissociated in 5%fetal bovine serum (FBS)/5%horse serum (HS)/ DMEM.…”

Astroglial-Conditioned Media and Growth Factors Modulate Proliferation and Differentiation of Astrocytes in Primary Culture

“…This factor interferes with cell proliferation and migration during brain development. ACM impair growth of meninges through a soluble inhibitory factor probably corresponding to PA in an in vitro model of glial-limiting membrane [5]. This protein is synthesized and released by astrocytes when stimulated with basic fibroblast growth factor (bFGF) [6].…”