Wenjia Liu1, Anna Konermann2, Tao Guo3, Andreas Jäger2, Liqiang Zhang4, Yan Jin5. 1. Research and Development Center for Tissue Engineering, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China; Department of Oral Histology and Pathology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China. 2. Department of Orthodontics, Medical Faculty, University of Bonn, Bonn, Germany. 3. Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China. 4. Research and Development Center for Tissue Engineering, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China. 5. Research and Development Center for Tissue Engineering, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China; Department of Oral Histology and Pathology, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China. Electronic address: yanjin@fmmu.edu.cn.
Abstract
BACKGROUND: Cellular plasticity and complex functional requirements of the periodontal ligament (PDL) assume a local stem cell (SC) niche to maintain tissue homeostasis and repair. Here, pathological alterations caused by inflammatory insults might impact the regenerative capacities of these cells. As bone homeostasis is fundamentally controlled by Wnt-mediated signals, it was the aim of this study to characterize the SC-like capacities of cells derived from PDL and to investigate their involvement in bone pathophysiology especially regarding the canonical Wnt pathway. METHODS: PDLSCs were investigated for their SC characteristics via analysis of cell surface marker expression, colony forming unit efficiency, proliferation, osteogenic differentiation and adipogenic differentiation, and compared to bone marrow derived mesenchymal SCs (BMMSCs). To determine the impact of both inflammation and the canonical Wnt pathway on osteogenic differentiation, cells were challenged with TNF-α, maintained with or without Wnt3a or DKK-1 under osteogenic induction conditions and investigated for p-IκBα, p-NF-κB, p-Akt, β-catenin, p-GSK-3β, ALP and Runx2. RESULTS: PDLSCs exhibit weaker adipogenic and osteogenic differentiation capacities compared to BMMSCs. TNF-α inhibited osteogenic differentiation of PDLSCs more than BMMSCs mainly through regulating canonical Wnt pathway. Blocking the canonical Wnt pathway by DKK-1 reconstituted osteogenic differentiation of PDLSCs under inflammatory conditions, whereas activation by Wnt3a increased osteogenic differentiation of BMMSCs. CONCLUSIONS: Our results suggest a diverse regulation of the inhibitory effect of TNF-α in BMMSCs and PDLSCs via canonical Wnt pathway modulation. GENERAL SIGNIFICANCE: These findings provide novel insights on PDLSC SC-like capacities and their involvement in bone pathophysiology under the impact of the canonical Wnt pathway.
BACKGROUND: Cellular plasticity and complex functional requirements of the periodontal ligament (PDL) assume a local stem cell (SC) niche to maintain tissue homeostasis and repair. Here, pathological alterations caused by inflammatory insults might impact the regenerative capacities of these cells. As bone homeostasis is fundamentally controlled by Wnt-mediated signals, it was the aim of this study to characterize the SC-like capacities of cells derived from PDL and to investigate their involvement in bone pathophysiology especially regarding the canonical Wnt pathway. METHODS: PDLSCs were investigated for their SC characteristics via analysis of cell surface marker expression, colony forming unit efficiency, proliferation, osteogenic differentiation and adipogenic differentiation, and compared to bone marrow derived mesenchymal SCs (BMMSCs). To determine the impact of both inflammation and the canonical Wnt pathway on osteogenic differentiation, cells were challenged with TNF-α, maintained with or without Wnt3a or DKK-1 under osteogenic induction conditions and investigated for p-IκBα, p-NF-κB, p-Akt, β-catenin, p-GSK-3β, ALP and Runx2. RESULTS: PDLSCs exhibit weaker adipogenic and osteogenic differentiation capacities compared to BMMSCs. TNF-α inhibited osteogenic differentiation of PDLSCs more than BMMSCs mainly through regulating canonical Wnt pathway. Blocking the canonical Wnt pathway by DKK-1 reconstituted osteogenic differentiation of PDLSCs under inflammatory conditions, whereas activation by Wnt3a increased osteogenic differentiation of BMMSCs. CONCLUSIONS: Our results suggest a diverse regulation of the inhibitory effect of TNF-α in BMMSCs and PDLSCs via canonical Wnt pathway modulation. GENERAL SIGNIFICANCE: These findings provide novel insights on PDLSC SC-like capacities and their involvement in bone pathophysiology under the impact of the canonical Wnt pathway.
Authors: Luciano Barreto Silva; Alexandrino Pereira Dos Santos Neto; Rachel Gomes Pelozo Pacheco; Severino Alves Júnior; Rebeca Ferraz de Menezes; Vanda Sanderana Macedo Carneiro; Natália Costa Araújo; Marcia Maria Fonseca da Silveira; Diana Santana de Albuquerque; Marleny Elizabeth Marquez de Martinez Gerbi; Pamella Recco Álvares; José Alcides Almeida de Arruda; Ana Paula Veras Sobral Journal: Open Dent J Date: 2016-05-24