The Role of Prep1 in the Regulation of Mesenchymal Stromal Cells.

Giorgia Maroni,Indira Krishnan,Piero Salvadori,Daniela Campani,Dmitry Penkov,Patricia Iozzo,Francesco Blasi,Daniele Panetta,Federica La Rosa,Maria Magli,Raffaele Luongo,Elena Levantini

doi:10.3390/ijms20153639

Abstract

Molecular mechanisms governing cell fate decision events in bone marrow mesenchymal stromal cells (MSC) are still poorly understood. Herein, we investigated the homeobox gene Prep1 as a candidate regulatory molecule, by adopting Prep1 hypomorphic mice as a model to investigate the effects of Prep1 downregulation, using in vitro and in vivo assays, including the innovative single cell RNA sequencing technology. Taken together, our findings indicate that low levels of Prep1 are associated to enhanced adipogenesis and a concomitant reduced osteogenesis in the bone marrow, suggesting Prep1 as a potential regulator of the adipo-osteogenic differentiation of mesenchymal stromal cells. Furthermore, our data suggest that in vivo decreased Prep1 gene dosage favors a pro-adipogenic phenotype and induces a “browning” effect in all fat tissues.

Highlights

Prep1 is a key developmental regulator, as its complete in vivo inactivation is embryonic lethal at the epiblast stage [1]
Prep1i/i bone marrow (BM) is characterized by a substantial presence of large adipocytes, as shown at 40× magnification, which are most probably responsible for the looser morphology observed in the hypomorphic BM
As our in vitro studies pointed to Prep1 as an important regulator of adipogenesis, we have verified this hypothesis in the BM, as well as in brown adipose tissue (BAT), and subcutaneous and visceral WAT

Summary

Introduction

Prep is a key developmental regulator, as its complete in vivo inactivation is embryonic lethal at the epiblast stage [1]. Hypomorphic Prep1i/i embryos, that express ~2% of normal Prep mRNA, have a milder phenotype, with frequent embryonic lethality at E17.5 [2]. Foetal liver Prep1i/i hematopoietic stem cells (HSCs) are rapidly exhausted, but still able to inefficiently repopulate irradiated hosts [5]. No phenotype is observed in mice in which Prep null deletion is studied in adult HSCs [6,7], hinting that mesenchymal stromal cells may contribute to hematopoietic phenotypes. We studied bone marrow (BM) mesenchymal stromal cells in Prep1i/i mice, where the level of Prep is drastically reduced

Methods

Results

Conclusion