New Insights into GFAP Negative Astrocytes in Calbindin D28k Immunoreactive Astrocytes.

Jie Xu

doi:10.3390/brainsci8080143

Abstract

Glial fibrillary acidic protein (GFAP) is commonly used as a specific marker for the identification of astrocytes. Nevertheless, it is known from the literature that astrocytes in situ in contrast to cultured astrocytes may feature lower levels of GFAP. In order to characterize the properties of GFAP in Calbindin D28k immunoreactive astrocytes, we use primary astrocyte cultures from cells of new-born mice. A double fluorescence immunocytochemical analysis reveals that GFAP in cultured Calbindin D28k astrocytes behaves differently depending on whether the medium contains foetal bovine serum (FBS) or not. The novelty in our study is, however, that a high percentage of Calbindin D28k cultured astrocytes in a medium with 10% FBS are GFAP negative. In addition, the study shows that Calbindin D28k astrocytes have (i) a different morphology and (ii) a higher concentration of Calbindin D28k in the nucleus than in the cytoplasm. The study provides new evidence that in order to fully understand the characteristics of astrocytes, astrocytes which are Calbindin D28k positive have to be investigated.

Highlights

Astrocytes are the major glial cell of the CNS
In a medium which contains foetal bovine serum (FBS), the majority of Calbindin D28k glial cells are stained positive for glial fibrillary acidic protein (GFAP) at day 1, while after 9 days only a small percentage of Calbindin D28k glial cells are stained for GFAP at day 1, while after 9 days only a small percentage of Calbindin D28k glial cells are positive for GFAP (Figures 1–3)
It seems that Calbindin D28k was localized stained positive for GFAP (Figures 1–3)

Summary

Introduction

Astrocytes are the major glial cell of the CNS. It’s assumed in the literature that astrocytes contain characteristic intermediate filaments, called glial filaments, which are mostly polymers of glial fibrillary acidic protein (GFAP). GFAP can be used for astrocyte identification [1]. The immunocytochemistry of GFAP is crucial for the identification of astrocytes [2]. Astrocytes are morphologically subdivided into protoplasmic astrocytes with short, thick, branching protrusions in the grey matter of the CNS and fibrous astrocytes with numerous, long and thin protrusions in the white matter of the CNS. The morphological differences are due to the cell content of GFAP [3]

Methods

Results

Discussion

Conclusion