Angiogenic Effects of Human Dental Pulp and Bone Marrow-Derived Mesenchymal Stromal Cells and their Extracellular Vesicles.

Greet Merckx,Sören Kuypers,Joy Irobi,Luc Michiels,Sarah Deville,Inge Nelissen,Baharak Hosseinkhani,Ivo Lambrichts,Annelies Bronckaers

doi:10.3390/cells9020312

Abstract

Blood vessel formation or angiogenesis is a key process for successful tooth regeneration. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) possess paracrine proangiogenic properties, which are, at least partially, induced by their extracellular vesicles (EVs). However, the isolation of BM-MSCs is associated with several drawbacks, which could be overcome by MSC-like cells of the teeth, called dental pulp stromal cells (DPSCs). This study aims to compare the angiogenic content and functions of DPSC and BM-MSC EVs and conditioned medium (CM). The angiogenic protein profile of DPSC- and BM-MSC-derived EVs, CM and EV-depleted CM was screened by an antibody array and confirmed by ELISA. Functional angiogenic effects were tested in transwell migration and chicken chorioallantoic membrane assays. All secretion fractions contained several pro- and anti-angiogenic proteins and induced in vitro endothelial cell motility. This chemotactic potential was higher for (EV-depleted) CM, compared to EVs with a stronger effect for BM-MSCs. Finally, BM-MSC CM, but not DPSC CM, nor EVs, increased in ovo angiogenesis. In conclusion, we showed that DPSCs are less potent in relation to endothelial cell chemotaxis and in ovo neovascularization, compared to BM-MSCs, which emphasizes the importance of choice of cell type and secretion fraction for stem cell-based regenerative therapies in inducing angiogenesis.

Highlights

Despite the strong progress in professional health care, current therapies are not able to regenerate the original physiological structure and function of damaged teeth
dental pulp stromal cells (DPSCs) and Bone marrow-derived mesenchymal stromal cells (BM-mesenchymal stromal cells (MSCs)) were positive for CD44, CD73 and CD90 (≥95%) and negative for CD34 and CD45 (≤5%)
This study only focused on the protein content of DPSC- and BM-MSC-derived extracellular vesicles (EVs), proangiogenic properties have been assigned to miRNAs transported by EVs

Summary

Introduction

Despite the strong progress in professional health care, current therapies are not able to regenerate the original physiological structure and function of damaged teeth. Tooth loss remains a major public health issue with a huge economic and social burden [1]. Regeneration of tooth pulp is intensively studied, since the current endodontic procedures consist of replacing infected pulp with inorganic materials (such as Gutta-percha), which results in a devitalized (dead) tooth [2]. Pulp removal structurally weakens the tooth and causes a higher susceptibility to infections and fractures [3]. The most important issue that must be considered for pulp tissue regeneration is angiogenesis, as an insufficient blood supply leads to necrosis [4,5]. Angiogenesis is the formation of new blood vessels from pre-existing ones by the sequence of extracellular matrix (ECM) degradation, endothelial cell

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