Folliculostellate cell interacts with pericyte via TGFβ2 in rat anterior pituitary

Abstract

The anterior pituitary gland comprises five types of endocrine cells plus non-endocrine cells including folliculostellate cells, endothelial cells, and capillary mural cells (pericytes). In addition to being controlled by the hypothalamic-pituitary-target organ axis, the functions of these cells are likely regulated by local cell and extracellular matrix (ECM) interactions. However, these complex interactions are not fully understood. We investigated folliculostellate cell-mediated cell-to-cell interaction. Using S100β-GFP transgenic rats, which express GFP in folliculostellate cells, we designed a three-dimensional cell culture to examine the effects of folliculostellate cells. Interestingly, removal of folliculostellate cells reduced collagen synthesis (Col1a1 and Col3a1). Because pericytes are important collagen-producing cells in the gland, we stained for desmin (a pericyte marker). Removal of folliculostellate cells resulted in fewer desmin-positive pericytes and less desmin mRNA. We then attempted to identify the factor mediating folliculostellate cell-pericyte interaction. RT-PCR and in situ hybridization revealed that the important profibrotic factor transforming growth factor beta-2 (TGFβ2) was specifically expressed in folliculostellate cells and that TGFβ receptor II was expressed in pericytes, endothelial cells, and parenchymal cells. Immunocytochemistry showed that TGFβ2 induced SMAD2 nuclear translocation in pericytes. TGFβ2 increased collagen synthesis in a dose-dependent manner. This action was completely blocked by TGFβ receptor I inhibitor (SB431542). Diminished collagen synthesis in folliculostellate cell-deficient cell aggregates was partially recovered by TGFβ2. TGFβ2-mediated folliculostellate cell-pericyte interaction appears to be essential for collagen synthesis in rat anterior pituitary. This finding sheds new light on local cell-ECM interactions in the gland. 159-170 229:2 FS cell interacts with pericyte via TGFβ2t tsukada and others

Fibromodulin Expression in Folliculostellate Cells and Pericytes Is Promoted by TGFβ Signaling in Rat Anterior Pituitary Gland

“…1c). As was the case in our previous report [28], TGFβ receptor II mRNA was detected in parenchymal cells, perivascular cells, and endothelial cells. Double staining showed that parenchymal cells were co-stained with S100 protein and that perivascular cells were co-stained with desmin (Fig.…”

“…It is a potent regulator of ECM synthesis, in which signaling stimulates synthesis of ECM components [20, 28, 29]. Indeed, our past and present findings show that TGFβ2 induced fibromodulin and collagen synthesis in pericytes [28].…”

“…Our previous study using a 3D cell culture system of rat anterior pituitary cells showed that TGFβ2 acts on pericytes and induces type I and III collagen synthesis [28]. In the present experiment, we used the same technique to evaluate the effect of TGFβ2 on fibromodulin expression.…”

“…Folliculostellate cells express various paracrine/autocrine factors [1], whereas pericytes are mural cells of capillaries and are the sole collagen-producing cells in rat anterior pituitary gland [5]. We recently identified a novel cell-to-cell interaction between these cells and discovered that transforming growth factor-beta 2 (TGFβ2) secreted from folliculostellate cells strongly induced collagen synthesis in pericytes [28]. …”

Effect of retinoic acid on midkine gene expression in rat anterior pituitary cells

“…Quantitative real-time PCR and RT-PCR was performed as described in our previous report [8,13]. The primers used to amplify cDNA fragments were listed in Table 1.…”