Biology subjects

Neeman, M.

Publications and source records attributed to Neeman, M..

3 recordsLinked to original sources

bioRxiv2020

Production of Hyaluronan by the Trophectoderm is a Prerequisite for Mouse Blastocyst Attachment

Embryo implantation requires execution of highly synchronized processes at the feto-maternal interface, initiated by blastocyst attachment to the endometrial epithelium. Hyaluronan is a major ECM component known to regulate adhesion-associated biological processes in various physiological settings. We hypothesized that hyaluronan may facilitate blastocyst attachment. In order to test our hypothesis, we characterized the blastocyst expression of hyaluronan synthesizing and degrading enzymes, as well as the expression of hyaluronan receptors during attachment. The functional impact of hyaluronan was challenged by the use of mouse transgenic blastocysts, in which genes encoding for hyaluronan synthesizing enzymes were deleted using lentiviral incorporation of Cas-9 endonuclease alongside specific short-guide RNAs into the embryonic trophectoderm. Embryos with transgenic trophectoderm were tested for their attachment in vitro, or assessed for implantation in vivo, upon transfer to foster dams. Deletion of the trophectoderm hyaluronan biosynthesis significantly reduced the number of blastocysts attached to human uterine epithelium cells in vitro. Reduced attachment was also observed in vivo, in pregnant mice carrying blastocysts with hyaluronan-depleted trophectoderm. In agreement, trophectoderm expression of osteopontin, was downregulated upon depletion of hyaluronan. MRI measurements revealed a decrease in uterine blood vessels permeability. Uterine expression of VEGF-A, PTGS-2 and uterine osteopontin, which constitute the immediate response to blastocyst attachment was also reduced. Furthermore, impaired implantation, associated with a decrease in hyaluronan synthesis in the mural trophectoderm, obtained upon tamoxifen treatment, has been recovered by LIF administration. These results demonstrate that estrogen-regulated hyaluronan-synthesis in the trophectoderm is indispensable for mouse blastocysts attachment to the uterine epithelium.

developmental biology↗

bioRxiv2020

Hyaluronan-NK cell Interaction Controls the Primary Vascular Barrier during Early Pregnancy

Successful implantation is associated with a unique spatial pattern of vascular remodeling, characterized by profound peripheral neo-vascularization surrounding a peri-embryo avascular niche. We hypothesized that hyaluronan controls the formation of the unique vascular pattern encompassing the embryo. This hypothesis was evaluated by genetic modification of hyaluronan metabolism specifically targeted to embryonic trophoblast cells. The outcome of altered hyaluronan deposition on uterine vascular remodeling and post-implantation development were analyzed by MRI, detailed histological examinations, and RNA-sequencing of uterine NK cells. Our experiments revealed that eliminating the anti-angiogenic hyaluronan, led to elevated expression of MMP-9, VEGF-A and its receptor VEGFR-2, accompanied by reduced recruitment of uterine NK cells. Further local decrease in VEGFR-3 resulted in impaired formation of vascular sinuous folds, ectopic angiogenesis and dysfunctional uterine NK cells. Conversely, enhanced deposition of hyaluronan caused the expansion of the maternal-embryo barrier, leading to an increased diffusion distance and aborted implantation. These results demonstrate a pivotal role for hyaluronan in successful pregnancy by fine-tuning the peri-embryo avascular niche and maternal vascular morphogenesis.

developmental biology↗

bioRxiv2019

BACH family members regulate angiogenesis and lymphangiogenesis by modulating VEGFC expression

Angiogenesis and lymphangiogenesis are key processes during embryogenesis as well as under physiological and pathological conditions. Vascular endothelial growth factor C (VEGFC), the ligand for both VEGFR2 and VEGFR3, is a central lymphangiogenic regulator that also drives angiogenesis. Here we report that members of the highly conserved BACH (BTB and CNC homology) family of transcription factors regulate VEGFC expression, through direct binding to its promoter. Accordingly, downregulation of bach2a hinders blood-vessel formation and impairs lymphatic sprouting in a vegfc-dependent manner during zebrafish embryonic development. In contrast, BACH1-overexpression enhances intratumoral blood-vessel density and peritumoral lymphatic vessel diameter in ovarian and lung mouse tumor models. The effects on the vascular compartment correlate spatially and temporally with BACH1 transcriptional regulation of VEGFC expression. Altogether, our results uncover a novel role for the BACH/VEGFC signaling axis in lymphatic formation during embryogenesis and cancer, providing a novel potential target for therapeutic interventions.

developmental biology↗