Fibromodulin reprogrammed cells: A novel cell source for bone regeneration

Abstract

Pluripotent or multipotent cell-based therapeutics are vital for skeletal reconstruction in non-healing critical-sized defects since the local endogenous progenitor cells are not often adequate to restore tissue continuity or function. However, currently available cell-based regenerative strategies are hindered by numerous obstacles including inadequate cell availability, painful and invasive cell-harvesting procedures, and tumorigenesis. Previously, we established a novel platform technology for inducing a quiescent stem cell-like stage using only a single extracellular proteoglycan, fibromodulin (FMOD), circumventing gene transduction. In this study, we further purified and significantly increased the reprogramming rate of the yield multipotent FMOD reprogrammed (FReP) cells. We also exposed the ‘molecular blueprint’ of FReP cell osteogenic differentiation by gene profiling. Radiographic analysis showed that implantation of FReP cells into a critical-sized SCID mouse calvarial defect, contributed to the robust osteogenic capability of FReP cells in a challenging clinically relevant traumatic scenario in vivo. The persistence, engraftment, and osteogenesis of transplanted FReP cells without tumorigenesis in vivo were confirmed by histological and immunohistochemical staining. Taken together, we have provided an extended potency, safety, and molecular profile of FReP cell-based bone regeneration. Therefore, FReP cells present a high potential for cellular and gene therapy products for bone regeneration.

Fibromodulin Is Essential for Fetal-Type Scarless Cutaneous Wound Healing

“…36,37 This finding, coupled with those from our current study, support the growing consensus that FM (and other small leucine-rich proteoglycans) has pleiotropic functions regulating intracellular signaling, cell fate determination, and stem cell niches 36e40 that extend far beyond its initially described roles in collagen assembly, organization, and degradation for extracellular matrix structural support. 18,41e43 In conclusion, the findings from our study suggest that FM alone is sufficient to restore scarless fetal repair to late-gestation animals, which normally heal with Figure 3 Fibromodulin (Fm) reduces transforming growth factor (Tgf)-b1 expression in embryonic day 18.5 (E18) fetal rat wounds.…”

CDKN2B upregulation prevents teratoma formation in multipotent fibromodulin-reprogrammed cells

“…Cell culture. Human newborn foreskin BJ fibroblasts (ATCC CRL-2522; ATCC) were cultured in a 4:1 mixture of DMEM (containing 4 mM l-glutamine, 1.0 g/L glucose, and 1.5 g/L sodium bicarbonate; Thermo Fisher Scientific) and Medium 199 (Thermo Fisher Scientific), supplemented with 10% FBS (Thermo Fisher Scientific) and 1% penicillin/ streptomycin (P/S; Thermo Fisher Scientific) (7). BJ fibroblasts were authenticated by Laragen Inc. and tested negative for mycoplasma contamination using the Universal Mycoplasma Detection Kit (ATCC; Supplemental Figure 9).…”

“…Importantly, FReP cells exhibit pluripotency marker expression and triploblastic differentiation capabilities similar to those of ESCs and iPSCs (5). From an efficacy standpoint, we previously demonstrated that human FReP cells formed more bone than human iPSCs in a critical-sized SCID mouse calvarial defect model (7). Moreover, unlike iPSCs, implantation of FReP cells in the kidney capsule of immunodeficient mice did not result in teratoma or any other tumor formation (5).…”

“…Both methodologies (a) offer freedom from the ethical and logistical constraints overshadowing ESC generation; (b) reprogram autologous cells, which significantly reduces the risk of immunogenic rejection; and (c) transform human dermal fibroblasts, a cell type that can be easily obtained and expanded from a skin biopsy (6), which may be preferred over the invasive harvest procedures required to obtain sufficient MSCs. Using this technology, dermal fibroblasts isolated from donors of different ages and sexes have been successfully reprogrammed into a multipotent state (5,7). The resultant dome-shaped, clustered FMOD-reprogrammed (FReP) cells are easily separated from the surrounding spindle-shaped, monolayer FReP-basal cells with a xeno-free and enzyme-free reagent developed for passaging human pluripotent stem cells (7).…”

“…Using this technology, dermal fibroblasts isolated from donors of different ages and sexes have been successfully reprogrammed into a multipotent state (5,7). The resultant dome-shaped, clustered FMOD-reprogrammed (FReP) cells are easily separated from the surrounding spindle-shaped, monolayer FReP-basal cells with a xeno-free and enzyme-free reagent developed for passaging human pluripotent stem cells (7). Importantly, FReP cells exhibit pluripotency marker expression and triploblastic differentiation capabilities similar to those of ESCs and iPSCs (5).…”