Cilia dynamics in cardiac regeneration in zebrafish (danio rerio).

Abstract

Ischemic injury in the human heart can lead to massive cell death and inelastic scar tissue formation, resulting in diminished cardiac function. In contrast, zebrafish (Danio rerio) can regenerate injured heart tissue within a month through events including immediate formation of a clot, organ-wide signaling events, dedifferentiation and proliferation of existing tissue near the wound, and finally resolution of the scar tissue. Primary cilia, located on the surface of cells, are membrane-bounded structures essential to many cellular functions. We have observed cilia in the regenerating cardiac tissue of zebrafish, and endeavor to understand their purpose in the complex processes of tissue regeneration. It is well known that primary cilia are integral facilitators of cell signaling. The complexity of cardiac tissue regeneration dictates that cell-to-cell signaling could occur to coordinate such anintricate process. We hypothesize that cilio genesis is required for heart regeneration in zebrafish, and that cilia may play a sensory role to assist the process of regeneration. This hypothesis was tested by using immunocyto chemistry to determine the stage, the length change, and localization of cilia in regenerating heart tissue as compared with uninjured tissue.Finding the localization and length change of cilia, and the time at which they proliferate conveys where they may potentially contribute to the process of regeneration. Understanding the mechanisms of cardiac tissue regeneration in zebrafish may lead to clinical application for cardiac injury in humans.