Organ Specificity of Mesenchymal Stromal Cells Underlie Homeostatic Tissue Maintenance of Multicellular Organisms.

Abstract

In biology, embryology has explained how multiple cell types arise from a fertilized egg and organs are formed. In the following chapter, we seek to explain the mechanisms of how organs from multiple cells are maintained in a homeostatic state. Understanding this state is essential for maintaining the health of us.

In general, organs consist of two major groups of cells: parenchymal cells and stromal cells. The properties of organs have been understood through the function of parenchymal cells. For example, hepatocytes are studied when investigating the function of the liver, and myocytes are studied as well. The interstitium, on the other hand, has been regarded as a scaffold for the parenchyma and as similar independent of organ origin. However, we focused on mesenchymal stromal cells (MSCs) for understanding organs.

In this study, we performed a comparative analysis of MSCs over six organs. We revealed the organ-specific character of MSCs and identified a muscle-maintaining functional molecule whose expression is reduced by aging. Its knockout mice exhibited a loss of muscle mass and muscle strength at a young age. The concept that MSCs maintain organ function, as demonstrated by this study, can be extended to other organs. In this presentation, we also would like to discuss the possibilities for future research development from a new perspective of 'understanding organs from the interstitium'.