Biology subjects

Cioffi, S.

Publications and source records attributed to Cioffi, S..

5 recordsLinked to original sources

bioRxiv2026

Vegfr3 is required in the Tbx1 expression domain for cardiac outflow tract development.

Gene inactivation in model organisms has identified numerous genes and signaling pathways involved in mammalian cardiac OFT development. Human genetics data have implicated the VEGFR3 gene in OFT development but when and where it is required is unknown. In this study we determined the sensitivity of the developing murine cardiac OFT to reduced Vegfr3 gene dosage and we tested whether its requirement is dependent upon TBX1, a known regulator of Vegfr3 expression in cardiac and lymphatic endothelial cells. We found that in the mouse, a single copy if the Vegfr3 gene was sufficient for normal cardiac OFT development in most cases. Mutation of a single copy of the Tbx1 gene greatly enhanced the sensitivity of OFT development to Vegfr3 dosage reduction and led to the formation of severe OFT anomalies. In addition, deletion of Vegfr3 in the Tbx1 expression domain also led to OFT abnormalities. We used RNAscope to reveal the location of Vegfr3 and Tbx1 transcripts in midterm mouse embryos. This revealed co-localization of these transcripts that was restricted to the aortic sac endothelium, suggesting that the distal OFT is a potential site of genetic interaction between Vegfr3 and TBX1 that is critical for normal OFT development.

developmental biology↗

bioRxiv2025

Neutrophil KLF2 regulates inflammasome-dependent neonatal mortality from endotoxemia

Preterm neonates die at a significantly higher rate from sepsis than full-term neonates, attributable to their dysregulated immune response. In addition to tissue destruction caused directly by bacterial invasion, an overwhelming cytokine response by the immune cells to bacterial antigens also results in collateral damage. Sepsis leads to decreased gene expression of a critical transcription factor, Kruppel-like factor-2 (KLF2), a tonic repressor of myeloid cell activation. Using a murine model of myeloid-Klf2 deletion, we show that loss of KLF2 is associated with decreased survival after endotoxemia in a developmentally dependent manner, with increased mortality at postnatal day 4 (P4) compared to P12 pups. This survival is significantly increased by neutrophil depletion. P4 knockout pups have increased pro-inflammatory cytokine levels after endotoxemia compared to P4 controls or P12 pups, with significantly increased levels of IL-1{beta}, a product of the activation of the NLRP3 inflammasome complex. Loss of myeloid-KLF2 at an earlier postnatal age leads to a greater increase in NLRP3 priming and activation and greater IL-1{beta} release by BMNs. Inhibition of NLRP3 inflammasome activation by MCC950 significantly increased survival after endotoxemia in P4 pups. Transcriptomic analysis of bone marrow neutrophils showed that loss of myeloid-KLF2 is associated with gene enrichment of pro-inflammatory pathways in a developmentally dependent manner. These data suggest that targeting KLF2 could be a novel strategy to decrease the pro-inflammatory cytokine storm in neonatal sepsis and improve survival in neonates with sepsis. Summary sentenceKLF2 regulates the developmental response to endotoxin in neonatal mice through the NLRP3 inflammasome signaling pathway.

immunology↗

bioRxiv2022

VEGFR3 modulates brain microvessel branching in a mouse model of 22q11.2 deletion syndrome

The loss of a single copy of TBX1 accounts for most of the clinical signs and symptoms of 22q11.2 deletion syndrome (22q11.2DS), a common genetic disorder that is characterized by multiple congenital anomalies and brain-related clinical problems, some of which likely have vascular origins. Tbx1 mutant mice have brain vascular anomalies, thus making them a useful model to gain insights into the brain disorders associated with the human disease. Here, we found that Tbx1 has a dynamic expression pattern in brain endothelial cells (ECs), including tip cells, during early vascularization, but it is not expressed in EC progenitors. Its main morphogenetic function in the brain is to regulate negatively filopodia biogenesis and vessel branching. Because of similar phenotypes reported for Vegfr3 loss of function, we pursued a mouse genetic approach to test TBX1-VEGFR3 interaction through gain and loss of function experiments. Vegfr3 is expressed in brain ECs with extensive overlap with Tbx1 expression. We demonstrate that inactivating Vegfr3 in the Tbx1 expression domain in a Tbx1 mutant background enhances vessel branching and filopodia formation to a greater extent than that observed in the individual mutants. Furthermore, using a mouse transgenic line, we show that increasing Vegfr3 expression in the Tbx1 expression domain fully rescued the vessel branching and filopodia phenotypes caused by Tbx1 loss of function. Similar results were obtained using an in vitro model of endothelial tubulogenesis. Overall, these results provide genetic evidence that Vegfr3 is a regulator of early vessel branching and filopodia formation in the brain, and is a likely critical effector of the brain vascular phenotype caused by Tbx1 loss of function.

developmental biology↗

bioRxiv2019

Tbx1 interacts genetically with Vegfr3 to regulate cardiac lymphangiogenesis in mice

The transcription factor TBX1 is the major gene implicated in 22q11.2 deletion syndrome. The complex clinical phenotype includes vascular anomalies and a recent report presented new cases of primary lymphedema in 22q11.2DS patients. We have previously shown that Tbx1 activates Vegfr3 gene expression in lymphatic endothelial cells and that this activation is critical for lymphatic vessel development in prenatal mice and for their survival post-natally. Using loss-of-function genetics and transgenesis, we show a strong genetic interaction between Tbx1 and Vegfr3 in cardiac lymphangiogenesis that causes cardiac lymphatic vessel anomalies in compound heterozygotes. Intriguingly, different aspects of the cardiac lymphatic phenotype were regulated independently by the two genes. Tbx1Cre-activated Vegfr3 transgene expression was able to rescue the morphological abnormalities in the cardiac lymphatic vessels of compound heterozygotes, but it did not rescue the severe cardiac lymphatic vessel hypoplasia observed in Tbx1 homozygotes. Moreover, our study revealed a differential sensitivity between the ventral and dorsal cardiac lymphatic networks to the effects of altered Tbx1 and Vegfr3 gene dosage. Overall, our study demonstrates that a fine dosage balance between Tbx1 and Vegfr3 is required to regulate the number and morphology of cardiac lymphatic vessels.

developmental biology↗

bioRxiv2019

Left Pulmonary Artery in 22q11.2 deletion syndrome. Echocardiographic evaluation in patients without cardiac defects and role of Tbx1 in mice.

Introduction and HypothesisPatients with 22q11 deletion syndrome (22q11.2DS) present, in about 75% of cases, typical patterns of cardiac defects, with a particular involvement on the ventricular outflow tract and great arteries. However, in this genetic condition the dimensions of the pulmonary arteries (PAs) never were specifically evaluated.\n\nWe measured both PAs diameter in patients with 22q11.2DS without cardiac defects, comparing these data to a normal control group. Moreover, we measured the PAs diameter in Tbx1 mutant mice. Finally, a cell fate mapping in Tbx1 mutants was used to study the expression of this gene in the morphogenesis of PAs.\n\nMethodsWe evaluated 58 patients with 22q11.2DS without cardiac defects. The control group consisted of 54 healthy subjects, matched for age and sex. All cases underwent a complete transthoracic echocardiography. Moreover, we crossed Tbx1+/- mice and harvested fetuses. We examined the cardiovascular phenotype of 8 wild type (WT), 37 heterozygous (Tbx1+/-) and 6 null fetuses (Tbx1-/-). Finally, we crossed Tbx1Cre/+mice with R26RmT-mG Cre reporter mice to study Tbx1 expression in the pulmonary arteries.\n\nResultsThe echocardiographic study showed that the mean of the LPA/RPA ratio in 22q11.2DS was smaller (0.80 {+/-} 0.12) than in controls (0.97 {+/-} 0.08; p < 0.0001).\n\nMouse studies resulted in similar data as the size of LPA and RPA was not significantly different in WT embryos, but in Tbx1+/- and Tbx1-/- embryos the LPA was significantly smaller than the RPA in both mutants (P=0.0016 and 0.0043, respectively). We found that Tbx1 is expressed near the origin of the PAs and in their adventitia.\n\nConclusionsChildren with 22q11.2DS without cardiac defects show smaller LPA compared with healthy subjects. Mouse studies suggest that this anomaly is due to haploinsufficiency of Tbx1. These data may be useful in the clinical management of children with 22q11.2DS and should guide further experimental studies as to the mechanisms underlying PAs development.

developmental biology↗