Developmental regulation of fatty acid binding protein in neural tissue

Abstract

Fatty acid binding proteins (FABP) constitute a family of small, cytosolic carriers of hydrophobic ligands. These proteins are thought to be important for lipid trafficking toward specific metabolic pathways, and are potentially important for the establishment of characteristic lipid compositions of neural tissue. In the embryonic chick retina and brain, FABP resembles the heart subtype, as determined by protein characterization and immunoblot studies. In this paper, the developmental expression and cellular localization of chick retinal FABP were examined. Results of immunoblot analysis suggest that FABP is maximally expressed around embryonic day 9 (E9) and declines thereafter. In adult retinas, FABP is barely detectable on a Western blot. Immunohistochemical staining of the retina shows light labeling on day E6 and a more intense staining throughout the retina on day E9. As the retina differentiates, labeling becomes increasingly localized. By day E l 8 subpopulations of ganglion cells and photoreceptor inner segments are stained, as are all photoreceptor cell bodies, most of the inner nuclear layer, and the nerve fiber layer. Staining is decreased in older retinas such that in adult animals, only light staining of the photoreceptor cell bodies is visible. The decrease in relative amount of FABP in the retina after day E9 suggests a role for FABP in the early stages of retinal differentiation. Localization in the retina is consistent with this hypothesis, as label becomes more restricted to those cells undergoing maturation at a particular developmental age. Thus, in young embryos (E6-E9), FABP immunolabeling is apparent throughout the retina, and transiently localizes at different ages (E12-E 15) to plexiform and nuclear layers. Near hatching (E18-E21), the photoreceptors are in the final stages of maturation, and are the principal cells immunoreactive for FABP. In the adult retina, FABP lightly labels only the photoreceptor cells bodies; thus, we conclude that chick retinal FABP is not involved in outer segment membrane homeostasis. Instead, FABP may serve to sequester fatty acids needed for the period of neurite outgrowth which occurs as the retina ends its mitotic cycles and begins the process of synaptogenesis. 0 1994 Wiley-Liss, Inc.

A retinal proteomics‐based study identifies αA‐crystallin as a sex steroid‐regulated protein

“…FABP5 is a small cytoplasmic protein responsible for the fatty acid uptake and transport. In the retina, it is upregulated during development and regeneration 13 or after stimuli leading to oxidative stress, and acts by scavenging reactive lipids 14, but it is virtually absent in adult animals 13. Our results accordingly demonstrate FABP5 resolving as single spot 13 at a very low level in the control adult retina and increasing by vehicle treatment as a possible adaptive defensive response to the intraocular injection‐induced stress.…”

The evolutionary relationship between the duplicated copies of the zebrafish fabp11 gene and the tetrapod FABP4, FABP5, FABP8 and FABP9 genes

“…2D). Sellner [20] reported a similar trend, whereby retinal FABP appears to be maximally expressed in the chicken retina around the ninth day of embryonic development and declines at later stages. Embryonic development in zebrafish spans 3 days, whereas embryonic development in chicken extends over 20–21 days.…”

Reactive changes of retinal astrocytes and Müller glial cells in kainate‐induced neuroexcitotoxicity

“…2003). BLBP is developmentally regulated in the embryonic chick retina and it is barely detected in the adult (Sellner, 1994). However, cellular localization of BLBP was not definitive, especially as it was expressed by Müller glial cells in the embryonic chick retina (Sellner, 1993) and in the retinal spheres of the postnatal rats (Engelhardt et al.…”