The need for bone grafts to repair bone defects is rapidly accelerating as our population ages. Bone defects have been successfully treated using autografts and allografts. However, these are less than ideal approaches since autograft availability is limited and can result in donor-site morbidity while allografts can be immunologically rejected and have the potential to transmit disease. The use of putative human mesenchymal stem cells (hMSC) combined with biocompatible scaffolds has great potential for treating bone defects, which would otherwise be treated with autografts or allografts. Unfortunately, the expansion of hMSC in vitro, which could increase the therapeutic potential of hMSC, reduces their osteogenic potential. The ability to expand hMSC in vitro while maintaining, or even enhancing, their osteogenic potential, could greatly enhance their therapeutic potential. Therefore, the goal of this project is to identify specific biomaterial surface characteristics and biophysical signals that interact synergistically in optimizing hMSC differentiation toward the osteoblastic lineage. Our overall hypothesis is that biomaterial surface characteristics, specifically nanoscale topography, sensitize cells to fluid flow thus increasing the effect of fluid flow on expansion of hMSC while also enhancing the osteogenic potential of hMSC. Using unique fluid flow protocols, novel biomaterial surface characteristics, atomic force microscopy, genetic engineering and transgenic animal models we will identify an environment that optimizes differentiation of hMSC towards the osteoblastic lineage and the signal transduction pathways involved in this mechanism. We will then examine whether these pre-treated hMSC are more osteogenic in vivo than non pre-treated hMSC. We will accomplish this through the completion, over a 5 year period, of 4 aims:
Aim 1, Examine the effect of surface topography on adhesion, proliferation and differentiation of hMSC, in the presence and absence of inhibitors of specific signaling pathways;
Aim 2, Determine stiffness and mechanosensitivity of hMSC on surfaces with varying nanoscale topographies;
Aim 3, Examine the effect of fluid flow, in the presence and absence of inhibitors of the PLC/calcineurin and PLC/ERK signaling pathways, on hMSC proliferation and differentiation;
and Aim 4, Examine in vivo osteogenesis of hMSC seeded onto HA/TCP scaffolds. By completing these aims we will not only develop novel strategies for bone tissue engineering but also provide mechanistic insight into the regulation of hMSC proliferation and differentiation.

Public Health Relevance

As the aged population increases the need for novel therapeutic approaches to musculoskeletal pathology will also increase. Tissue engineering exploiting adult stem cells is one such approach. This project will develop novel musculoskeletal tissue engineering protocols combining nanotechnology, adult stem cells and biophysical forces that will lead to strategies to replace bone loss to disease, injury and aging.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR054937-04
Application #
8231561
Study Section
Musculoskeletal Tissue Engineering Study Section (MTE)
Program Officer
Wang, Fei
Project Start
2009-04-01
Project End
2014-02-28
Budget Start
2012-03-01
Budget End
2013-02-28
Support Year
4
Fiscal Year
2012
Total Cost
$331,582
Indirect Cost
$113,782
Name
Pennsylvania State University
Department
Orthopedics
Type
Schools of Medicine
DUNS #
129348186
City
Hershey
State
PA
Country
United States
Zip Code
17033
Loiselle, Alayna E; Wei, Lai; Faryad, Muhammad et al. (2013) Specific biomimetic hydroxyapatite nanotopographies enhance osteoblastic differentiation and bone graft osteointegration. Tissue Eng Part A 19:1704-12
Lim, Jung Yul; Loiselle, Alayna E; Lee, Jeong Soon et al. (2011) Optimizing the osteogenic potential of adult stem cells for skeletal regeneration. J Orthop Res 29:1627-33
Salvi, Joshua D; Lim, Jung Yul; Donahue, Henry J (2010) Increased mechanosensitivity of cells cultured on nanotopographies. J Biomech 43:3058-62
Salvi, Joshua D; Lim, Jung Yul; Donahue, Henry J (2010) Finite element analyses of fluid flow conditions in cell culture. Tissue Eng Part C Methods 16:661-70