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Development of the follicular basement membrane during human gametogenesis and early folliculogenesis.

Heeren AM, van Iperen L, Klootwijk DB, de Melo Bernardo A, Roost MS, Gomes Fernandes MM, Louwe LA, Hilders CG, Helmerhorst FM, van der Westerlaken LA, Chuva de Sousa Lopes SM - BMC Dev. Biol. (2015)

Bottom Line: In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood.This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, The Netherlands. marijneheeren@gmail.com.

ABSTRACT

Background: In society, there is a clear need to improve the success rate of techniques to restore fertility. Therefore a deeper knowledge of the dynamics of the complex molecular environment that regulates human gametogenesis and (early) folliculogenesis in vivo is necessary. Here, we have studied these processes focusing on the formation of the follicular basement membrane (BM) in vivo.

Results: The distribution of the main components of the extracellular matrix (ECM) collagen IV, laminin and fibronectin by week 10 of gestation (W10) in the ovarian cortex revealed the existence of ovarian cords and of a distinct mesenchymal compartment, resembling the organization in the male gonads. By W17, the first primordial follicles were assembled individually in that (cortical) mesenchymal compartment and were already encapsulated by a BM of collagen IV and laminin, but not fibronectin. In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.

Conclusions: The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood. This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

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Related in: MedlinePlus

Fibronectin expression in human fetal female and male gonads during first and second trimester. (A-F) Fibronectin (green) expression in the mesenchymal compartment of developing female gonads (A, A’, B, B’, D, D’, E, E’) and male gonads (C, C’, F, F’) during first and second trimester. Germ cells (red) were identified by the early marker OCT4 (nuclear) and late marker VASA (cytoplasmic). The same secondary antibody was used to detect OCT4 and VASA, because the two proteins localize to different cellular compartments (nucleus and cytoplasm, respectively) and their expression can therefore be clearly distinguished. Red arrows point to the BM of the OSE, and white arrows point to the BM of blood vessels. Note that occasional autofluorescent red blood cells are visible as red/orange cells inside blood vessels. Scalebars are 100 μm.
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Fig4: Fibronectin expression in human fetal female and male gonads during first and second trimester. (A-F) Fibronectin (green) expression in the mesenchymal compartment of developing female gonads (A, A’, B, B’, D, D’, E, E’) and male gonads (C, C’, F, F’) during first and second trimester. Germ cells (red) were identified by the early marker OCT4 (nuclear) and late marker VASA (cytoplasmic). The same secondary antibody was used to detect OCT4 and VASA, because the two proteins localize to different cellular compartments (nucleus and cytoplasm, respectively) and their expression can therefore be clearly distinguished. Red arrows point to the BM of the OSE, and white arrows point to the BM of blood vessels. Note that occasional autofluorescent red blood cells are visible as red/orange cells inside blood vessels. Scalebars are 100 μm.

Mentions: To further support the existence of ovarian cords at W9-W12, we have immunostained female gonads for the two other main components of ECM, laminin (Figure 3) and fibronectin (Figure 4). Laminin was highly expressed throughout the cortex of the ovary with no specific enrichment in ovarian BM, except for the BM enveloping the developing blood vessels (white arrow in Figure 3B’); whereas in males, laminin was concentrated in the BM of the seminiferous cords and the blood vessels (green and white arrows in Figure 3C’). Moreover, we noted that few scattered (male and female) germ cells seemed to contain prominent collagen IV-rich and laminin-rich granules in their cytoplasm (white asterisks in Figures 1B, 1C, 2A’, 2B’, 3A’, 3B’, and 3C’). By performing 3D reconstructions on confocal images, we confirmed that the granules were indeed in the cytoplasm of female germ cells (Figure 5A and 5B) and male germ cells (data not shown). In general, the granules of laminin seemed more numerous than those of collagen IV.Figure 3


Development of the follicular basement membrane during human gametogenesis and early folliculogenesis.

Heeren AM, van Iperen L, Klootwijk DB, de Melo Bernardo A, Roost MS, Gomes Fernandes MM, Louwe LA, Hilders CG, Helmerhorst FM, van der Westerlaken LA, Chuva de Sousa Lopes SM - BMC Dev. Biol. (2015)

Fibronectin expression in human fetal female and male gonads during first and second trimester. (A-F) Fibronectin (green) expression in the mesenchymal compartment of developing female gonads (A, A’, B, B’, D, D’, E, E’) and male gonads (C, C’, F, F’) during first and second trimester. Germ cells (red) were identified by the early marker OCT4 (nuclear) and late marker VASA (cytoplasmic). The same secondary antibody was used to detect OCT4 and VASA, because the two proteins localize to different cellular compartments (nucleus and cytoplasm, respectively) and their expression can therefore be clearly distinguished. Red arrows point to the BM of the OSE, and white arrows point to the BM of blood vessels. Note that occasional autofluorescent red blood cells are visible as red/orange cells inside blood vessels. Scalebars are 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307144&req=5

Fig4: Fibronectin expression in human fetal female and male gonads during first and second trimester. (A-F) Fibronectin (green) expression in the mesenchymal compartment of developing female gonads (A, A’, B, B’, D, D’, E, E’) and male gonads (C, C’, F, F’) during first and second trimester. Germ cells (red) were identified by the early marker OCT4 (nuclear) and late marker VASA (cytoplasmic). The same secondary antibody was used to detect OCT4 and VASA, because the two proteins localize to different cellular compartments (nucleus and cytoplasm, respectively) and their expression can therefore be clearly distinguished. Red arrows point to the BM of the OSE, and white arrows point to the BM of blood vessels. Note that occasional autofluorescent red blood cells are visible as red/orange cells inside blood vessels. Scalebars are 100 μm.
Mentions: To further support the existence of ovarian cords at W9-W12, we have immunostained female gonads for the two other main components of ECM, laminin (Figure 3) and fibronectin (Figure 4). Laminin was highly expressed throughout the cortex of the ovary with no specific enrichment in ovarian BM, except for the BM enveloping the developing blood vessels (white arrow in Figure 3B’); whereas in males, laminin was concentrated in the BM of the seminiferous cords and the blood vessels (green and white arrows in Figure 3C’). Moreover, we noted that few scattered (male and female) germ cells seemed to contain prominent collagen IV-rich and laminin-rich granules in their cytoplasm (white asterisks in Figures 1B, 1C, 2A’, 2B’, 3A’, 3B’, and 3C’). By performing 3D reconstructions on confocal images, we confirmed that the granules were indeed in the cytoplasm of female germ cells (Figure 5A and 5B) and male germ cells (data not shown). In general, the granules of laminin seemed more numerous than those of collagen IV.Figure 3

Bottom Line: In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood.This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy and Embryology, Leiden University Medical Center, Einthovenweg 20, 2333, Leiden, ZC, The Netherlands. marijneheeren@gmail.com.

ABSTRACT

Background: In society, there is a clear need to improve the success rate of techniques to restore fertility. Therefore a deeper knowledge of the dynamics of the complex molecular environment that regulates human gametogenesis and (early) folliculogenesis in vivo is necessary. Here, we have studied these processes focusing on the formation of the follicular basement membrane (BM) in vivo.

Results: The distribution of the main components of the extracellular matrix (ECM) collagen IV, laminin and fibronectin by week 10 of gestation (W10) in the ovarian cortex revealed the existence of ovarian cords and of a distinct mesenchymal compartment, resembling the organization in the male gonads. By W17, the first primordial follicles were assembled individually in that (cortical) mesenchymal compartment and were already encapsulated by a BM of collagen IV and laminin, but not fibronectin. In adults, in the primary and secondary follicles, collagen IV, laminin and to a lesser extent fibronectin were prominent in the follicular BM.

Conclusions: The ECM-molecular niche compartimentalizes the female gonads from the time of germ cell colonization until adulthood. This knowledge may contribute to improve methods to recreate the environment needed for successful folliculogenesis in vitro and that would benefit a large number of infertility patients.

Show MeSH
Related in: MedlinePlus