Synergetic effects of hBMSCs and hPCs in osteogenic differentiation and their capacity in the repair of critical-sized femoral condyle defects

Potential of periosteal cells in bone and cartilage regeneration: a systematic review

Introduction: The unavailability of adequate human primary cells presents multiple challenges in terms of bone and cartilage regeneration and disease modeling experiments in vitro. Periosteal cells (PCs), which represent promising skeletal stem cell sources, could be a promising strategy in tissue engineering. The present study aimed to summarize the characteristics of PCs to investigate the efficacy of these cells in bone and cartilage regeneration in different models, paying special attention to the comparison of bone marrow stromal cells (BMSCs). Methods: A comprehensive literature search was conducted in Embase, PubMed/MEDLINE, Web of Science, and Scopus for articles published in English until April 2023. Only original researches in which PCs were employed for bone or cartilage regeneration experiments were included. Results: A total of 9140 references were retrieved. After screening the results, 36 publications were considered to be eligible for inclusion in the present literature review. Overall, PCs demonstrated beneficial bone and cartilage regenerative efficacy compared to the bare scaffold since almost all included studies reported positive results. The 9 studies assessing the differences in bone formation capacity between PCs and BMSCs indicated that PCs exhibited stronger in vivo osteogenic differentiation capabilities compared to BMSCs, while the other study demonstrated stronger chondrogenic potential of BMSCs. Discussion: PCs demonstrated beneficial to bone regenerative efficacy compared to the bare scaffold with a low risk of most studies included. However, the cartilage formation capacity of BMSCs still needs to be investigated due to the limited research available and the certain risk of bias. PCs exhibited higher osteogenic capabilities compared to BMSCs in combination with various scaffolds in vivo with good evidence. Further researches are needed to elucidate the comparative benefits of cartilage regeneration. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023411522, CRD42023411522.

Characterization and potential of periosteum-derived cells: an overview

As a thin fibrous layer covering the bone surface, the periosteum plays a significant role in bone physiology during growth, development and remodeling. Over the past several decades, the periosteum has received considerable scientific attention as a source of mesenchymal stem cells (MSCs). Periosteum-derived cells (PDCs) have emerged as a promising strategy for tissue engineering due to their chondrogenic, osteogenic and adipogenic differentiation capacities. Starting from the history of PDCs, the present review provides an overview of their characterization and the procedures used for their isolation. This study also summarizes the chondrogenic, osteogenic, and adipogenic abilities of PDCs, serving as a reference about their potential therapeutic applications in various clinical scenarios, with particular emphasis on the comparison with other common sources of MSCs. As techniques continue to develop, a comprehensive analysis of the characterization and regulation of PDCs can be conducted, further demonstrating their role in tissue engineering. PDCs present promising potentials in terms of their osteogenic, chondrogenic, and adipogenic capacities. Further studies should focus on exploring their utility under multiple clinical scenarios to confirm their comparative benefit over other commonly used sources of MSCs.

Molecular Mechanism of Long Noncoding RNA SNHG14 in Osteogenic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells through the NEDD4L/FOXA2/PCP4 Axis

Bone marrow-derived mesenchymal stem cells (BMSCs) have a superior potential of osteogenic differentiation (OD) and a promising stem cell type to treat bone defects. This study sought to investigate the molecular mechanism of long noncoding RNA small nucleolar RNA host gene 14 (SNHG14) in OD of BMSCs. Western blot analysis or RT-qPCR showed that SNHG14, neural precursor cell expressed developmentally downregulated 4-like (NEDD4L), and Purkinje cell protein 4 (PCP4) were upregulated whereas forkhead box A2 (FOXA2) was declined in OD of BMSCs. RT-qPCR and cell staining showed that SNHG14 downregulation repressed OD of BMSCs, as manifested by reductions in osteopontin and osteocalcin levels, the mineralization degree, and alkaline phosphatase activity. RNA/Co/chromatin immunoprecipitation and dual-luciferase assays and determination of mRNA stability and ubiquitination level showed that SNHG14 bound to human antigen R improves NEDD4L mRNA stability and expression, further promoted FOXA2 ubiquitination to inhibit FOXA2 expression, and then reduced FOXA2 enrichment on the PCP4 promoter to upregulate PCP4 transcription. Functional rescue experiments showed that the overexpression of NEDD4L or PCP4 and knockdown of FOXA2 both attenuated the inhibition of SNHG14 downregulation on OD of BMSCs. Overall, our findings suggested that SNHG14 promoted OD of BMSCs through the NEDD4L/FOXA2/PCP4 axis.

Synergistic impact of platelet rich plasma-heparin sulfate with hydroxyapatite/zirconia on the osteoblast differentiation potential of adipose-derived mesenchymal stem cells

3D porous hydroxyapatite (HA) has been reinforced by zirconia (ZrO₂) coating and impregnation with a combination of platelet rich plasma (PRP) as a source of growth factors (GFs) and Heparin sulfate (HS) to sustain the release of GFs. Adipose mesenchymal stem cells (ADMSCs) were characterized by flow cytometry for CD (cluster of differentiation) 44, CD105, CD106, CD34 and CD144, along with checking the multipotency by differentiation into the adipocytes and osteoblasts. Then, they were cultured on the scaffold treated with and without osteogenic media on days 7, 14 and 21. Electron micrograph and PKH staining show that the ADMSCs have a fusiform phenotype in the absence of osteogenic induction. Cell viability assay shows a higher number of the viable cells on the PRP-containing scaffolds than PRP-free scaffolds on day 7. Colorimetric evaluation, quantitative RT-PCR and immunocytochemistry demonstrate that PRP and HS significantly elevate the alkaline phosphatase enzyme activity and also accelerate the production of both early and mid-osteogenic markers, including collagen I and osteopontin expression with and without osteogenic conditions. The PRP-HS also accelerates the expression of the late osteogenic marker, osteocalcin, in both mRNA and protein level expression with a peak on day 21. In conclusion, supplementation of HA/ZrO₂ with PRP/HS has a synergistic impact on the ADMSCs, even in the absence of chemical induction. It seems that HA/ZrO₂/PRP/HS scaffold provides a higher osteoconductive microenvironment for stem cell differentiation to osteoblasts.

Clinical Application of Bone Marrow Mesenchymal Stem/Stromal Cells to Repair Skeletal Tissue

There has been an escalation in reports over the last decade examining the efficacy of bone marrow derived mesenchymal stem/stromal cells (BMSC) in bone tissue engineering and regenerative medicine-based applications. The multipotent differentiation potential, myelosupportive capacity, anti-inflammatory and immune-modulatory properties of BMSC underpins their versatile nature as therapeutic agents. This review addresses the current limitations and challenges of exogenous autologous and allogeneic BMSC based regenerative skeletal therapies in combination with bioactive molecules, cellular derivatives, genetic manipulation, biocompatible hydrogels, solid and composite scaffolds. The review highlights the current approaches and recent developments in utilizing endogenous BMSC activation or exogenous BMSC for the repair of long bone and vertebrae fractures due to osteoporosis or trauma. Current advances employing BMSC based therapies for bone regeneration of craniofacial defects is also discussed. Moreover, this review discusses the latest developments utilizing BMSC therapies in the preclinical and clinical settings, including the treatment of bone related diseases such as Osteogenesis Imperfecta.

Vertebral Bone Marrow-Derived Mesenchymal Stromal Cells from Osteoporotic and Healthy Patients Possess Similar Differentiation Properties In Vitro

Osteoporosis is a disease characterized by low bone mass and an increased risk of fractures. Although several cellular players leading to osteoporosis have been identified, the role of mesenchymal stromal cells (MSC) is still not fully elaborated. The aim of this study was, therefore, to isolate and characterize MSCs from vertebral body of healthy non-osteoporotic and osteoporotic patients, with a particular focus on their osteogenic differentiation potential. Isolated MSCs were characterized by their osteogenic, adipogenic, and chondrogenic differentiation, as well as surface marker expression, proliferation behavior, and immunomodulatory capacity. The mineralization process was confirmed using Alizarin Red S and alkaline phosphatase (ALP) stains and further evaluated by determining ALP activity, mineral deposition, and free phosphate ion release. MSCs from both healthy and osteoporotic patients showed common fibroblast-like morphology and similar proliferation behavior. They expressed the typical MSC surface markers and possessed immunomodulatory capacity. Both groups demonstrated solid trilineage differentiation potential; osteogenic differentiation was further confirmed by increased ALP activity, deposition of inorganic crystals, phosphate ion release, and expression of osteoblast marker genes. Overall, MSCs from osteoporotic and non-osteoporotic patients showed neither a difference in general MSC features nor in the detailed analysis regarding osteogenic differentiation. These data suggest that vertebral body MSCs from osteoporotic patients were not impaired; rather, they possessed full osteogenic potential compared to MSCs from non-osteoporotic patients.

Effects of various antimicrobial agents on multi-directional differentiation potential of bone marrow-derived mesenchymal stem cells

Antimicrobial drugs of several classes play an important role in the treatment of bone and joint infections. In addition to fighting pathogenic microorganisms, the effects of drugs on local tissues and cells are also related to the course and prognosis of bone and joint infections. The multi-directional differentiation potential of bone marrow-derived mesenchymal stem cells (MSCs) is essential for tissue repair after local injury, which is directly related to the recovery of bone, cartilage, and medullary adipose tissue. Our previous studies and the literature indicate that certain antimicrobial agents can regulate the differentiation potential of bone marrow-derived MSCs. Here, in order to systematically analyze the effects of various antimicrobial drugs on local tissue regeneration, we comprehensively review the studies on the effects of these drugs on MSC differentiation, and classify them according to the three differentiation directions (osteogenesis, chondrogenesis, and adipogenesis). Our review demonstrates the specific effects of different antimicrobial agents on bone marrow-derived MSCs and the range of concentrations at which they work, and provides a basis for drug selection at different sites of infection.

Current advances for bone regeneration based on tissue engineering strategies

Bone tissue engineering (BTE) is a rapidly developing strategy for repairing critical-sized bone defects to address the unmet need for bone augmentation and skeletal repair. Effective therapies for bone regeneration primarily require the coordinated combination of innovative scaffolds, seed cells, and biological factors. However, current techniques in bone tissue engineering have not yet reached valid translation into clinical applications because of several limitations, such as weaker osteogenic differentiation, inadequate vascularization of scaffolds, and inefficient growth factor delivery. Therefore, further standardized protocols and innovative measures are required to overcome these shortcomings and facilitate the clinical application of these techniques to enhance bone regeneration. Given the deficiency of comprehensive studies in the development in BTE, our review systematically introduces the new types of biomimetic and bifunctional scaffolds. We describe the cell sources, biology of seed cells, growth factors, vascular development, and the interactions of relevant molecules. Furthermore, we discuss the challenges and perspectives that may propel the direction of future clinical delivery in bone regeneration.

Bacitracin promotes osteogenic differentiation of human bone marrow mesenchymal stem cells by stimulating the bone morphogenetic protein-2/Smad axis

Bacitracin, a widely used metallopeptide antibiotic, has been reported to be locally used in treating wounds without systemic adverse reactions. Our preliminary study showed that bacitracin might enhance the osteogenic differentiation of human bone marrow mesenchymal stem cells (HBMSCs). The present study investigated whether bacitracin affects the osteogenic differentiation of HBMSCs and the molecular mechanisms involved. The proliferation of HBMSCs in the presence of bacitracin was examined using a cell counting kit-8 (CCK-8) assay. The effects of bacitracin on the cell cycle and apoptosis of HBMSCs were observed using flow cytometry assay. Staining and quantitative assays for alkaline phosphatase (ALP) staining, collagen deposition (Sirius Red), and mineralization (Alizarin Red) were used to study osteogenic differentiation of HBMSCs. The expression of osteogenic differentiation markers was detected using quantitative reverse transcription polymerase chain reaction (RT-qPCR) analyses. The activation of related signaling pathways was examined using a luciferase reporter assay and western blotting. Bacitracin treatment increased osteogenic differentiation of HBMSCs without cytotoxicity and did not adversely affect cell cycle progression or apoptosis. The luciferase reporter assay showed that bacitracin activated the transcription of bone morphogenetic protein-2 (BMP2) gene, a key gene in the BMP2/Smad signaling axis. Western blotting indicated that this axis was markedly activated by bacitracin stimulation of osteogenesis. Moreover, the activation of Smad phosphorylation and osteogenic differentiation by bacitracin was inhibited by a transforming growth factor (TGF)-β/Smad inhibitor (LDN-193189 HCl) and small interfering RNA (siRNA) gene silencing (si-BMP2). In conclusion, our results suggest that bacitracin can promote osteogenesis of HBMSCs by activating the BMP2/Smad signaling axis.

The antimicrobial peptide KR-12 promotes the osteogenic differentiation of human bone marrow stem cells by stimulating BMP/SMAD signaling

KR-12 is the smallest fragment of human antimicrobial peptide cathelicidin (LL-37), and could play key roles in the treatment of multiple infections, including osteomyelitis. Our preliminary work found that KR-12 enhances the osteogenic differentiation of human bone marrow mesenchymal stem cells (HBMSCs). The present study investigated whether KR-12 affects HBMSC osteogenic differentiation, as well as the molecular mechanisms involved. HBMSC proliferation in the presence of KR-12 was observed with a cell counting 8 assay, and its effects on HBMSC cell cycle progression and apoptosis were examined by flow cytometry. Alkaline phosphatase, Sirius Red, and Alizarin Red staining and quantitative assays were used to study the osteogenic differentiation of HBMSCs. The expression of osteogenic differentiation markers was detected by real-time quantitative PCR analysis. The activation of potentially related pathways was examined by luciferase reporter assay and western blot analysis. KR-12 treatment increased the osteogenic differentiation of HBMSCs without cytotoxicity and did not influence the cell cycle or induce apoptosis. Luciferase reporter assays showed that KR-12 activated the transcription of bone morphogenetic protein 2 (BMP2), a key gene in the BMP/SMAD pathway. Western blot analysis indicated that BMP/SMAD signaling was markedly activated by KR-12 stimulation in osteogenic induction conditions. SMAD phosphorylation was activated by KR-12 treatment, and was inhibited by both a transforming growth factor-β/SMAD inhibitor (LDN-193189 HCL) and BMP2 small interfering RNA (si-BMP2). LDN-193189 HCL and si-BMP2 treatment also abolished the KR-12-induced osteogenic differentiation of HBMSCs. In conclusion, our results suggest that KR-12 promotes HBMSC osteogenesis through the activation of BMP/SMAD signaling.

KR-12 is the smallest fragment of human antimicrobial peptide cathelicidin (LL-37), and could play key roles in the treatment of multiple infections, including osteomyelitis.

Fabrication of 3D Scaffolds with Precisely Controlled Substrate Modulus and Pore Size by Templated-Fused Deposition Modeling to Direct Osteogenic Differentiation

Scaffolds with tunable mechanical and topological properties fabricated by templated-fused deposition modeling promote increased osteogenic differentiation of bone marrow stem cells with increasing substrate modulus and decreasing pore size. These findings guide the rational design of cell-responsive scaffolds that recapitulate the bone microenvironment for repair of bone damaged by trauma or disease.