Mesenchymal Stem Cells (MSCs) are powerful multipotent progenitor cells that are present in many tissues, such as blood, bone, adipose tissue, muscle, and cartilage. MSCs exist during embryonic development and throughout life in humans and animals to provide progenitor cells for tissue homeostasis. MSC are common progenitors of osteoblasts and adipocytes, and a reciprocal relationship between osteogenic and adipogenic differentiation of MSC has been demonstrated. It is thought that intervention with this increased adipogenesis that occurs at the expense of osteogenesis in bones may be beneficial to improve skeletal integrity. The control of lineage specific differentiation of MSC into specific cell types is achieved through specific master regulators of gene expression such as PPAR-γ for adipocyte differentiation and Runx2 for osteoblast differentiation. Better understanding of bioactive molecules that regulate such master regulators of differentiation is vital to enhance our current knowledge of MSC regulation and improve animal growth and skeletal health.
We also use chicken MSCs isolated from compact bones and fat tissues to understand regulation of osteogenic and adipogenic differentiation of MSCs. The chicken is an important model organism for biology, agriculture, and medicine. The domestic chicken is evolutionarily positioned to bridge the gap between mammals and non-amniote vertebrates, providing critical discoveries in development, immunology, oncology, and genetics. The chick limb bud has been investigated as a model of molecular and cellular patterning in vertebrates, leading to the discovery of the proximal distal patterning in the limb by Hh signalling. Furthermore, the chicken has unique growth kinetics and metabolisms. The broiler chicken, the fast-growing meat-type chicken, develops bones and muscle rapidly compared to mammals. Unlike mammals, laying hens have two types of bones: cortical and medullary bones. Medullary bone is a special kind of woven bone lying in the marrow cavities of the laying hens. This bone cycles on a daily basis and contributes 35 to 40 percent of the calcium in each eggshell, indicating that rapid bone turnover occurs in medullary bones. This suggests that chicken MSCs may respond much faster and/or differently to metabolic and physiological changes in the body compared to mammalian MSCs. Thus, understanding of the regulation of chicken MSCs would enhance our knowledge of molecular regulation of MSCs and provide benefits to various fields, such as biology, agriculture, and medicine.
- Stem Cell Biology
- Regulation of Osteogenesis and Adipogenesis
- Osteoporosis, and Obesity
- Publications by Woo Kyun Kim may be found at PubMed.