Generation of reconstituted hemato-lymphoid murine embryos by placental transplantation into embryos lacking HSCs

Overload of Neprilysin in Placental Extracellular Vesicles Disrupts CNP-NPRB-Mediated Communication Between Vascular Endothelial and Smooth Muscle Cells: A Trigger for Symptoms of Preeclampsia

BACKGROUND

Preeclampsia is a placenta-origin pregnancy complication. Although its development has long been divided into 2 stages: abnormal placentation (stage I) and the release of factors from the hypoperfused placenta into circulation, triggering preeclampsia due to endothelial dysfunction (stage II), the placenta-derived substances coupling the 2 stages remain unclear.

METHODS

Extracellular vesicles (EVs) from normal and preeclampsia-complicated placentas were intravenously administered to pregnant mice, and blood pressure was recorded throughout pregnancy. The differential cargo, including NEP (neprilysin), of placental EVs in normal and preeclamptic placentas was identified by LC-MS, and the cell types involved in NEP expression in the placenta were determined by single-cell RNA sequencing. The effects of placental EVs and recombinant mouse NEP on the uterine arteries were assessed by myography. Placenta-specific NEP overexpression mice were established by in situ injection of adenovirus. The binding affinity between NEP and the vasodilative peptides was determined using an Octet instrument. NEP-overexpressing HUVECs were established to measure CNP (C-type natriuretic peptide) release and cocultured with NPRB (natriuretic peptide receptor-B) knockdown vascular smooth muscle cells (VSMCs) to measure cGMP production in VSMCs.

RESULTS

Placental EVs from preeclamptic pregnancies impaired vascular endothelium-dependent vasodilation and induced preeclampsia in mice. NEP was expressed predominantly by syncytiotrophoblasts and upregulated in placental EVs from preeclamptic pregnancies. Recombinant mouse NEP administration resulted in outcomes like those of administration of placental EVs from preeclamptic pregnancies. Placenta-specific NEP overexpression disturbed maternal hemodynamics, resulting in hypertension and proteinuria of the mice. CNP exhibited high binding affinity for NEP, and NEP upregulation in HUVECs inhibited CNP release, which further influenced the production of cGMP in VSMCs; however, this effect was largely blunted in NPRB-deficient VSMCs.

CONCLUSIONS

Excessive NEP in placental EVs from preeclamptic pregnancies is transported into the endothelial cells of uterine and placental arteries to cleave and degrade CNP, resulting in compromised CNP paracrine activity and NPRB-mediated cGMP production in adjacent VSMCs and triggering the hypertensive manifestation of preeclampsia.

Intraplacental injection of AAV9-CMV-iCre results in the widespread transduction of multiple organs in double-reporter mouse embryos

Adeno-associated virus serotype 9 (AAV9) has become a popular tool for gene transfer because of its ability to cross the blood-brain barrier and efficiently transduce genetic material into a variety of cell types. The study utilized GRR (Green-to-Red Reporter) mouse embryos, in which the expression of iCre results in the disappearance of Green Fluorescent Protein (GFP) expression and the detection of Discosoma sp. Red Fluorescent Protein (DsRed) expression by intraplacental injection. Our results demonstrate that AAV9-CMV-iCre can transduce multiple organs in embryos at developmental stages E9.5-E11.5, including the liver, heart, brain, thymus, and intestine. These findings suggest that intraplacental injection of AAV9-CMV-iCre is a viable method for the widespread transduction of GRR mouse embryos.

In utero transplantation of myoblasts and adipose-derived mesenchymal stem cells to murine models of Duchenne muscular dystrophy does not lead to engraftment and frequently results in fetal death

Introduction

Duchenne muscular dystrophy (DMD) is a progressive disease that leads to damage of muscle and myocardium due to genetic abnormalities in the dystrophin gene. In utero cell transplantation that might facilitate allogenic transplantation is worth considering to treat this disease.

Methods

We performed allogeneic in utero transplantation of GFP-positive myoblasts and adipose-derived mesenchymal stem cells into murine DMD model animals. The transplantation route in this study was fetal intraperitoneal transplantation and transplacental transplantation. Transplanted animals were examined at 4-weeks old by immunofluorescence staining and RT-qPCR.

Results

No GFP-positive cells were found by immunofluorescence staining of skeletal muscle and no GFP mRNA was detected by RT-qPCR in any animal, transplantation method and cell type. Compared with previous reports, myoblast transplantation exhibited an equivalent mortality rate, but adipose-derived stem cell (ASC) transplantation produced a higher mortality rate.

Conclusions

In utero transplantation of myoblasts or ASCs to murine models of DMD does not lead to engraftment and, in ASC transplantation primarily, frequently results in fetal death.