Localization of epidermal-type fatty acid binding protein in macrophages in advanced atretic follicles of adult mice

Abstract

The localization of epidermal-type fatty acid binding protein (E-FABP) in the mature mouse ovary was examined by immuno-light and electron microscopy. Numerous macrophages immunopositive for both anti-E-FABP and F4/80 antibodies, together with immunonegative cells, were found in advanced atretic follicles that had eccentric lumens containing deformed ova. While some E-FABP-immunopositive macrophages were spider in shape and appeared singly, others, especially close to the lumen, were round and voluminous and tended to be aggregated. The voluminous macrophages contained phagosomes of various sizes and they were regarded as those actively involved in the phagocytosis of apoptotic granulosa cells. E-FABP-immunopositive macrophages and their processes were often apposed to adjacent immunonegative cells, and some of them lined the lumen containing deformed ova. On the other hand, E-FABP-immunonegative cells in the atretic follicles were classified into two types: the one, a minority, was characterized by small mitochondria containing non-tubular cristae and presumably represented residual granulosa cells, while the other dominant type was characterized by large mitochondria containing tubular cristae and presumably represented theca cells originally surrounding the follicles to be atretic. The present detection of E-FABP-immunopositivity selectively in macrophages of the atretic follicles suggests possible involvement of E-FABP and/or its ligand fatty acids in the process of follicular atresia, and it makes more reliable the identification of the advanced atretic follicles with the antral spaces obliterated, which could provide further details on the histology of the follicular atresia than before.

Identification of FABP7 in fibroblastic reticular cells of mouse lymph nodes

“…Myeloid-derived cells, including macrophages and DCs, in the tissues express different species of FABP molecules: FABP4 is expressed in the foam cells accumulating in atherosclerotic lesions (Atkins et al 2008), FABP5 in the DCs of Peyer's patches (Suzuki et al 2009), and atretic ovarian follicles (Nourani et al 2005), whereas FABP7 is expressed in liver Kupffer cells . Such spatial heterogeneity in FABP expression in macrophages and/or DCs indicates that the expression levels of FABP are closely related to the intra-or extracellular lipid environment of these cells, and are suited to their specific functions in situ.…”

Incidence and significance of cystic structures in the ovaries of gadoid fish

“…The functionality of the oocyte epithelium probably changes when it becomes squamous and multistratified. The presence of some macrophages and multinuclear cells within the cyst envelope may indicate an inflammatory response, although macrophages are usually observed in normal atretic follicles too (Besseau and Faliex, 1994;Nourani et al, 2005).…”

Discrete localization of various fatty-acid-binding proteins in various cell populations of mouse retina

“…Although the mechanism of E-FABP involvement in the phagocytosis remains to be elucidated, the expression of FABPs in cells with the phagocytic ability has been repeatedly reported, such as that of A-FABP in isolated/in vitro macrophages and adipocytes (Pelton et al 1999;Fu et al 2000;Makowski et al 2001;Kazemi et al 2005) and that of E-FABP in dendritic cells and macrophages in the thymus, spleen, lymph node, and ovary (Owada et al 2001;Nourani et al 2005;Abdelwahab et al 2007).…”