The Primary Cilium: Emerging Role as a Key Player in Fibrosis

The myofibroblast is the culprit in the pathogenesis of fibrosis in systemic sclerosis (SSc). Activation of morphogen signaling pathways has been shown to be critically involved in organ fibrosis. Remarkably, the cellular receptors and key molecules from these signaling pathways are localized in the primary cilium. The primary cilium is a unique cellular organelle present in virtually all cells. This article summarizes recent studies evaluating the association between primary cilia and morphogen signaling driving myofibroblast transition and subsequent fibrosis.

Emerging observations implicate dysfunctional primary cilia in fibrosis in many different tissues and organs. Primary cilia seem to be necessary for the initiation of the transition and sustained activation of myofibroblasts. We summarize recent progress in this field and propose the primary cilium as a potential mediator of fibrosis pathogenesis in SSc. Understanding the contributions of primary cilia in fibrosis may ultimately inform the development of entirely new approaches for fibrosis prevention and treatment.