Platelet-Derived Growth Factor Stimulated Migration of Bone Marrow Mesenchymal Stem Cells into an Injectable Gelatin-Hydroxyphenyl Propionic Acid Matrix.

Wanting Niu,Abdulmonem Alshihri,Ravikumar Rajappa,Lishan Wang,Motoichi Kurisawa,Teck Chuan Lim,Myron Spector

doi:10.3390/biomedicines9020203

Abstract

Bone marrow mesenchymal stem cells (bMSCs) are responsible in the repair of injured tissue through differentiation into multiple cell types and secretion of paracrine factors, and thus have a broad application profile in tissue engineering/regenerative medicine, especially for the musculoskeletal system. The lesion due to injury or disease may be a closed irregular-shaped cavity deep within tissue necessitating an injectable biomaterial permissive of host (endogenous) cell migration, proliferation and differentiation. Gelatin-hydroxyphenyl propionic acid (Gtn-HPA) is a natural biopolymer hydrogel which is covalently cross-linked by horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) in situ and can be delivered to the lesion by needle injection. Growth factors and cytokines can be directly incorporated into the gel or into nano- and micro-particles, which can be employed for sustained release of biomolecules while maintaining their bioactivity. In this study, we selected polyelectrolyte complex nanoparticles (PCNs) prepared with dextran sulfate and chitosan as the carrier for platelet-derived growth factor (PDGF)-BB and stromal cell-derived factor (SDF)-1α, which have been tested effectively in recruiting stem cells. Our in vitro results showed a high degree of viability of bMSCs through the process of Gtn-HPA covalent cross-linking gelation. The Gtn-HPA matrix was highly permissive of bMSC migration, proliferation, and differentiation. PDGF-BB (20 ng/mL) directly incorporated into the gel and, alternatively, released from PCNs stimulated bMSC migration and proliferation. There were only small differences in the results for the direct incorporation of PDGF into the gel compared with its release from PCNs, and for increased doses of the growth factor (200 ng/mL and 2 µg/mL). In contrast, SDF-1α elicited an increase in migration and proliferation only when released from PCNs; its effect on migration was notably less than PDGF-BB. The in vitro results demonstrate that PDGF-BB substantially increases migration of bMSCs into Gtn-HPA and their proliferation in the gel, and that these benefits can be derived from incorporation of a relatively low dose of the growth factor directly into the gel. These findings commend the use of Gtn-HPA/PDGF-BB as an injectable therapeutic agent to treat defects in musculoskeletal tissues.

Highlights

For certain regenerative medicine applications, the reparative potential of endogenous stem and progenitor cells including mesenchymal stem cells (MSCs) may be able to be tapped by recruitment of the cells into the injury site
Gelatin-hydroxyphenyl propionic acid (Gtn-HPA), which is a natural biopolymer-based hydrogel that is covalently cross-linkable in vivo through the oxidative coupling of phenol moiety catalyzed by horseradish peroxidase (HRP) and propagated by H2 O2, Reference [9] has been shown to accommodate neural stem cell migration, Reference [10] astrocyte activation and proliferation [11], recruit Bone marrow mesenchymal stem cells (bMSCs) migration and osteogenic differentiation [12], and promote MSC endothelial differentiation and tube formation under certain conditions [13,14]
Incorporated directly into the gel or into polyelectrolyte complex nanoparticles (PCNs) greatly stimulates the number of migrating bMSCs and the distance they travel in the gelatin-hydroxyphenyl propionic acid (Gtn-HPA)

Summary

Introduction

For certain regenerative medicine applications, the reparative potential of endogenous stem and progenitor cells including mesenchymal stem cells (MSCs) may be able to be tapped by recruitment of the cells into the injury site. Several types of injectable polymers have undergone investigation, including: photo-polymerizable polymers [1]; self-assembling peptides [2]; shear-thinning (thixotropic) polymers [3]; and cryo gels [4,5] Another class of injectable polymers is capable of undergoing enzyme-mediated covalent cross-linking (e.g., horseradish peroxidase, tyrosinase, laccase, transglutaminase) In the horseradish peroxidase (HRP)-induced polymerization, the enzyme catalyzes the di-phenolic formation of phenol-conjugated polymer backbones (e.g., gelatin, hyaluronic acid) with hydrogen peroxide (H2 O2 ) [6,7,8,9]. Gelatin-hydroxyphenyl propionic acid (Gtn-HPA), which is a natural biopolymer-based hydrogel that is covalently cross-linkable in vivo through the oxidative coupling of phenol moiety catalyzed by HRP and propagated by H2 O2 , Reference [9] has been shown to accommodate neural stem cell migration, Reference [10] astrocyte activation and proliferation [11], recruit bMSC migration and osteogenic differentiation [12], and promote MSC endothelial differentiation and tube formation under certain conditions [13,14]

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Conclusion