Pentosan polysulfate binds to STRO-1+ mesenchymal progenitor cells, is internalized, and modifies gene expression: a novel approach of pre-programing stem cells for therapeutic application requiring their chondrogenesis

Abstract

BackgroundThe pharmaceutical agent pentosan polysulfate (PPS) is known to induce proliferation and chondrogenesis of mesenchymal progenitor cells (MPCs) in vitro and in vivo. However, the mechanism(s) of action of PPS in mediating these effects remains unresolved.In the present report we address this issue by investigating the binding and uptake of PPS by MPCs and monitoring gene expression and proteoglycan biosynthesis before and after the cells had been exposed to limited concentrations of PPS and then re-established in culture in the absence of the drug (MPC priming).MethodsImmuno-selected STRO-1+ mesenchymal progenitor stem cells (MPCs) were prepared from human bone marrow aspirates and established in culture. The kinetics of uptake, shedding, and internalization of PPS by MPCs was determined by monitoring the concentration-dependent loss of PPS media concentrations using an enzyme-linked immunosorbent assay (ELISA) and the uptake of fluorescein isothiocyanate (FITC)-labelled PPS by MPCs. The proliferation of MPCs, following pre-incubation and removal of PPS (priming), was assessed using the Wst-8 assay method, and proteoglycan synthesis was determined by the incorporation of 35SO4 into their sulphated glycosaminoglycans. The changes in expression of MPC-related cell surface antigens of non-primed and PPS-primed MPCs from three donors was determined using flow cytometry. RNA sequencing of RNA isolated from non-primed and PPS-primed MPCs from the same donors was undertaken to identify the genes altered by the PPS priming protocol.ResultsThe kinetic studies indicated that, in culture, PPS rapidly binds to MPC surface receptors, followed by internalisation and localization within the nucleus of the cells. Following PPS-priming of MPCs and a further 48 h of culture, both cell proliferation and proteoglycan synthesis were enhanced. Reduced expression of MPC-related cell surface antigen expression was promoted by the PPS priming, and RNA sequencing analysis revealed changes in the expression of 42 genes.ConclusionThis study has shown that priming of MPCs with low concentrations of PPS enhanced chondrogenesis and MPC proliferation by modifying their characteristic basal gene and protein expression. These findings offer a novel approach to re-programming mesenchymal stem cells for clinical indications which require the repair or regeneration of cartilaginous tissues such as in osteoarthritis and degenerative disc disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-017-0723-y) contains supplementary material, which is available to authorized users.

Pentosan polysulfate sodium prevents functional decline in chikungunya infected mice by modulating growth factor signalling and lymphocyte activation

“…In accordance with the literature, our study showed that mice treated with PPS appeared to have better myocyte regeneration and less cartilage damage when compared to CHIKV-infected untreated animals ( S3 Fig ). More recently, the same group demonstrated that PPS enhances chondrogenesis by altering genetic and proteomic signatures leading to increased proliferation of MSCs [ 32 ]. It is possible that similar mechanisms are responsible for the protection against muscle and cartilage damage seen in CHIKV-infected PPS-treated mice.…”

“…Interestingly, the growth factor functional group had the greatest number of our top DEGs (13/50) meaning it is the group which saw the most modulated genes from PPS treatment. Moreover, it is known that PPS can stimulate MSCs in vitro [ 31 , 32 ]. Perhaps this mechanism occurs via one of the newly identified growth factors and leads to decreased cartilage damage during CHIKV infection.…”

Pentosan Polysulfate Affords Pleotropic Protection to Multiple Cells and Tissues

“…PPS is thus chondroprotective and there is a well-documented rationale for its use in the treatment of OA and RA [ 6 ]. Furthermore, PPS promotes proliferation and differentiation of bone marrow stromal mesenchymal stem cells to a chondrogenic phenotype [ 77 , 158 ]. PPS-stimulated chondroprogenitor stem cells have been used to treat OA cartilage [ 159 ].…”

“…PPS localizes in the nucleus of stromal stem cells, promotes development of chondroprogenitor cell lineages, ECM synthesis and discal repair by resident disc cells, offering new opportunities in discal repair biology [ 61 ]. In culture, PPS rapidly binds to MSC surface receptors, and is internalized and localized to the nucleus, inducing cell proliferation and differentiation, and facilitating expansion of chondroprogenitor cell lineages with improved proteoglycan synthesis and ECM synthesizing profiles [ 158 ]. Priming of MSCs with PPS enhances chondrogenesis and MSC proliferation by modifying basal gene and protein expression and offers a means of programming chondroprogenitor MSC lineages of potential application in the repair or regeneration of cartilaginous tissues in OA and degenerative disc disease [ 158 ].…”

Importance of Matrix Cues on Intervertebral Disc Development, Degeneration, and Regeneration

“…Aggrecan, hyaluronic acid, and other GAG-based hydrogel systems and their biomimetic equivalents are needed moving forward. There is significant research in this regard applied to cartilage engineering [201][202][203][204][205][206][207][208][209][210], including systems that can be localised within ECM tissue through the incorporation of HA-specific binding peptides [201,205,206] and via steric interactions with collagen type VI and perlecan [211]. Some of these systems have been applied to the IVD [212], most notably in the case of a cytocompatible large aggrecan mimic, which has been chemically, structurally, and mechanically characterised and injected ex vivo into bovine NP tissue [211].…”