Astrocyte lineage differentiation profiles of the fetal human telencephalon

Abstract

Introduction. Brain functioning is kept by both neuronal cell activity and macroglia, i.e., astrocytes and oligodendrocytes. The current data on the prenatal development of the human brain are scarce, and gliogenesis is less studied than cortical neurogenesis. Normal limits and variations and spatiotemporal patterns of glial differentiation in human brain development remain poorly studied. Materials and methods. We used human fetal autopsy samples from the Collection of the Laboratory of Nervous System Development of Avtsyn Research Institute of Human Morphology. For immune and morphological analysis, samples of 38 fetal cerebral hemispheres at stages from 8 postconceptional weeks to birth were chosen. Results. We provided the results of the pilot comparative immune and morphological study with the panel of markers (GFAP, ALDH1L1, FABP-7) of the fetal human telencephalon in prenatal ontogenesis. Specific differentiation and maturation of the astrocyte population on the telencephalon start before early fetal period (12–13 gestational weeks). GFAP+ and ALDH1L1+ astrocyte populations in early human telencephalon are still to be studied for their homology. Analysis of GFAP+ and ALDH1L1+ glioblast distribution proposes dorsal proliferative zone as a source for fibrous cortical astrocytes. Comparative immune and morphological analysis of FABP-7+ neuroblasts in the fetal telencephalon questions whether FABP-7 cells belong to astrocyte population at early prenatal human ontogenesis. Conclusion. In the telencephalon, temporal and/or spatiotemporal translational profiles of these three antigens differ, which indicates that the astrocyte population is heterogeneous in early ontogenesis. Keywords: human brain development, telencephalon, glial differentiation, astrocytes, astrocyte fate lineage, GFAP, ALDH1L1, FABP-7