Biology subjects

Lazar, S.

Publications and source records attributed to Lazar, S..

3 recordsLinked to original sources

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↗

bioRxiv2020

RECAS9: Recombining wild species introgression via mitotic gene editing in barley

Genetic loci underlying variation in traits with agronomic importance or genetic risk factors in human diseases have been identified by linkage analysis and genome-wide association studies. However, narrowing down the mapping to the individual causal genes and variations within these is much more challenging, and so is the ability to break linkage drag between beneficial and unfavourable loci in crop breeding. We developed RECAS9 as a transgene-free approach for precisely targeting recombination events by delivering CRISPR/Cas9 ribonucleotide protein (RNP) complex into heterozygous mitotic cells for the barley (Hordeum vulgare) Heat3.1 locus. A wild species (H. spontaneum) introgression in this region carries the agronomical unfavourable tough rachis phenotype (non-brittle) allele linked with a circadian clock accelerating QTL near GIGANTEA gene. We delivered RNP, which was targeted between two single nucleotide polymorphism (SNPs), to mitotic calli cells by particle bombardment. We estimated recombination events by next generation sequencing (NGS) and droplet digital PCR (ddPCR). While NGS analysis grieved from confounding effects of PCR recombination, ddPCR analysis allowed us to associate RNP treatment on heterozygous individuals with significant increase of homologous directed repair (HDR) between cultivated and wild alleles, with recombination rate ranging between zero to 57%. These results show for the first time in plants a directed and transgene free mitotic recombination driven by Cas9 RNP, and provide a starting point for precise breeding and fine scale mapping of beneficial alleles from crop wild relatives.

genetics↗

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↗