Vitamin D3 Stimulates Proliferation Capacity, Expression of Pluripotency Markers, and Osteogenesis of Human Bone Marrow Mesenchymal Stromal/Stem Cells, Partly through SIRT1 Signaling.

Ana Borojević,Diana Bugarski,Borko Gobeljić,Slavko Mojsilović,Milena Živanović,Tamara Kukolj,Aleksandra Jauković,Hristina Obradović,Željko Zečević,Marija Simić,Dragana Vujić,Drenka Trivanović

doi:10.3390/biom12020323

Abstract

The biology of vitamin D3 is well defined, as are the effects of its active metabolites on various cells, including mesenchymal stromal/stem cells (MSCs). However, the biological potential of its precursor, cholecalciferol (VD3), has not been sufficiently investigated, although its significance in regenerative medicine—mainly in combination with various biomaterial matrices—has been recognized. Given that VD3 preconditioning might also contribute to the improvement of cellular regenerative potential, the aim of this study was to investigate its effects on bone marrow (BM) MSC functions and the signaling pathways involved. For that purpose, the influence of VD3 on BM-MSCs obtained from young human donors was determined via MTT test, flow cytometric analysis, immunocytochemistry, and qRT-PCR. Our results revealed that VD3, following a 5-day treatment, stimulated proliferation, expression of pluripotency markers (NANOG, SOX2, and Oct4), and osteogenic differentiation potential in BM-MSCs, while it reduced their senescence. Moreover, increased sirtuin 1 (SIRT1) expression was detected upon treatment with VD3, which mediated VD3-promoted osteogenesis and, partially, the stemness features through NANOG and SOX2 upregulation. In contrast, the effects of VD3 on proliferation, Oct4 expression, and senescence were SIRT1-independent. Altogether, these data indicate that VD3 has strong potential to modulate BM-MSCs’ features, partially through SIRT1 signaling, although the precise mechanisms merit further investigation.

Highlights

Bone marrow mesenchymal stromal/stem cells (BM-MSCs) were initially discovered as a non-hematopoietic fraction of the bone marrow niche, capable of fully reconstructing the hematopoietic microenvironment [1]
The results presented in our study demonstrate that vitamin D3 precursor cholecalciferol (VD3) increased proliferation of human BM-MSCs obtained from young donors after 1 day at higher concentrations (20 nM and 40 nM), while this effect was noticed after longer 2-day and 5-day incubation periods at all tested concentrations
The results of this study provide new evidence related to the potential of vitamin D3/cholecalciferol (VD3) to improve the regenerative potential of BM-MSCs, and offer a possible mechanistic basis of its action, supporting its use as a supplement in bone regeneration strategies

Summary

Introduction

Bone marrow mesenchymal stromal/stem cells (BM-MSCs) were initially discovered as a non-hematopoietic fraction of the bone marrow niche, capable of fully reconstructing the hematopoietic microenvironment [1]. Different MSCs have been discovered in virtually all tissues, BM-MSCs represent the most thoroughly studied type of these cells with prevalence in clinical studies [3,4]. As for bone tissue repair, BM-MSCs’ therapeutic potential has been associated with their capacity to directly differentiate into cells of osteogenic lineage, as well as to generate an appropriate regenerative microenvironment via secretion of various growth factors [5]. Considered to be a cornerstone of bone tissue engineering, the application of BM-MSCs has been combined with various types of biomaterials to facilitate the ossification process and improve clinical therapy of delayed bone healing—usually related to various bone diseases, injuries, or tumor surgery [5]. Some of the recent advances that have emerged with an aim to develop more effective therapies for enhanced bone regeneration propose loading of different hybrid biomaterial matrices or 3D scaffolds with vitamin D3 [6,7,8,9]

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