Highlights d Increases in adipose mass lead to an irreversible increase in adipocyte number d Adipocyte number is linked to the adipose expression of a set of growth factors d Among these, only TGFb3 stimulates adipocyte progenitor proliferation d Tgfb3 +/À mice display adipose hypertrophy and glucose intolerance upon weight gain
Although palatal shelf adhesion is a crucial event during palate development, little work has been carried out to determine which molecules are responsible for this process. Furthermore, whether altered palatal shelf adhesion causes the cleft palate presented by Tgf-b 3 null mutant mice has not yet been clarified. Here, we study the presence/distribution of some extracellular matrix and cell adhesion molecules at the time of the contact of palatal shelves in both wild-type and Tgf-b 3 null mutant palates of two strains of mice (C57/BL/6J (C57), and MF1) that develop cleft palates of different severity. We have performed immunohistochemistry with antibodies against collagens IV and IX, laminin, fibronectin, the a 5 -and b 1 -integrins, and ICAM-1; in situ hybridization with a Nectin-1 riboprobe; and palatal shelf cultures treated or untreated with TGF-b 3 or neutralizing antibodies against fibronectin or the a 5 -integrin. Our results show the location of these molecules in the wild-type mouse medial edge epithelium (MEE) of both strains at the time of the contact of palatal shelves; the heavier (C57) and milder (MF1) alteration of their presence in the Tgf-b 3 null mutants; the importance of TGF-b 3 to restore their normal pattern of expression; and the crucial role of fibronectin and the a 5 -integrin in palatal shelf adhesion. We thus provide insight into the molecular bases of this important process and the cleft palate presented by Tgf-b 3 null mutant mice.Key words cleft palate Á Tgf-b 3 Á mouse Á collagen Á laminin Á fibronectin Á a 5 b 1 -integrin Á ICAM-1 Á Nectin-1
Folic acid (FA) is essential for numerous bodily functions. Its decrease during pregnancy has been associated with an increased risk of congenital malformations in the progeny. The relationship between FA deficiency and the appearance of cleft palate (CP) is controversial, and little information exists on a possible effect of FA on palate development. We investigated the effect of a 2–8 weeks’ induced FA deficiency in female mice on the development of CP in their progeny as well as the mechanisms leading to palatal fusion, i.e. cell proliferation, cell death, and palatal-shelf adhesion and fusion. We showed that an 8 weeks’ maternal FA deficiency caused complete CP in the fetuses although a 2 weeks’ maternal FA deficiency was enough to alter all the mechanisms analyzed. Since transforming growth factor-β3 (TGF-β3) is crucial for palatal fusion and since most of the mechanisms impaired by FA deficiency were also observed in the palates of Tgf-β3null mutant mice, we investigated the presence of TGF-β3 mRNA, its protein and phospho-SMAD2 in FA-deficient (FAD) mouse palates. Our results evidenced a large reduction in Tgf-β3 expression in palates of embryos of dams fed an FAD diet for 8 weeks; Tgf-β3 expression was less reduced in palates of embryos of dams fed an FAD diet for 2 weeks. Addition of TGF-β3 to palatal-shelf cultures of embryos of dams fed an FAD diet for 2 weeks normalized all the altered mechanisms. Thus, an insufficient folate status may be a risk factor for the development of CP in mice, and exogenous TGF-β3 compensates this deficit in vitro.
The Tgf-β3 null mutant mouse palate presents several cellular anomalies that lead to the appearance of cleft palate. One of them concerns the cell proliferation of both the palatal medial edge epithelium and mesenchyme. In this work, our aim was to determine whether there was any variation in the presence/distribution of several cell proliferation-related molecules that could be responsible for the cell proliferation defects observed in these palates. Our results showed no difference in the presence of EGF-R, PDGF-A, TGF-β2, Bmp-2, and Bmp-4, and differences were minimal for FGF-10 and Shh. However, the expression of EGF and Msx-1 changed substantially. The shift of the EGF protein expression was the one that most correlated with that of cell proliferation. This molecule is regulated by TGF-β3, and experiments blocking its activity in culture suggest that EGF misexpression in the Tgf-β3 null mutant mouse palate plays a role in the cell proliferation defect observed.
This study suggests that an adequate folic acid/folate status plays a key role in the formation of ocular tissues and structures, whereas a vitamin deficiency is negatively associated with a normal eye development even after a short-term exposure.
Abstract:It is widely accepted that maternal folic acid (FA) deficiency during pregnancy is a risk factor for abnormal development. The tongue, with multiple genes working together in a coordinated cascade in time and place, has emerged as a target organ for testing the effect of FA during development. A FA-deficient (FAD) diet was administered to eight-week-old C57/BL/6J mouse females for 2-16 weeks. Pregnant dams were sacrificed at gestational day 17 (E17). The tongues and heads of 15 control and 210 experimental fetuses were studied. In the tongues, the maximum width, base width, height and area were compared with width, height and area of the head. All measurements decreased from 10% to 38% with increasing number of weeks on maternal FAD diet. Decreased head and tongue areas showed a harmonic reduction (Spearman nonparametric correlation, Rho = 0.802) with respect to weeks on a maternal FAD diet. Tongue congenital abnormalities showed a 10.9% prevalence, divided in aglossia (3.3%) and microglossia (7.6%), always accompanied by agnathia (5.6%) or micrognathia (5.2%). This is the first time that tongue alterations have been related experimentally to maternal FAD diet in mice. We propose that the tongue should be included in the list of FA-sensitive birth defect organs due to its relevance in several key food and nutrition processes.
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