MSCs: Paracrine effects

Abstract

Historically, mesenchymal stromal/stem cells (MSCs) have been characterized by their capacity to support hematopoiesis and differentiate into various connective tissue cell types. However, in the past decade, the field of MSC research has witnessed tremendous growth, spurred principally by studies showing that the cells are efficacious in treating a broad array of diseases. Renewed interest in MSC biology has also yielded new insights into their developmental origin, contribution to the hematopoietic stem cell niche, and mechanism of action in promoting tissue repair and regeneration. In the latter case, MSCs have been shown to secrete a bevy of proteins and other molecules that exhibit trophic, angiogenic, immunomodulatory, neuro-regulatory, anti-inflammatory, and anti-apoptotic activity and that function to restore homeostasis at sites of tissue injury and in response to disease. Herein, we provide an overview of the paracrine functions of MSCs by describing the different classes of proteins secreted by cells, the influence of the local microenvironment on their expression, and their therapeutic effects in various experimental animal models of disease.