Editorial: molecular insights into systemic sclerosis-associated interstitial lung disease

Management of Systemic-Sclerosis-Associated Interstitial Lung Disease

Although scleroderma-associated interstitial lung disease (SSc-ILD) is a significant contributor to both morbidity and mortality, its pathogenesis is largely unclear. Pulmonary function tests and high-resolution computed tomographic scanning continue to be the most effective tools to screen for lung involvement and to monitor for disease progression. More research and better biomarkers are needed to identify patients most at risk for developing SSc-ILD as well as to recognize which of these patients will progress to more severe disease. Although immunosuppression remains the mainstay of treatment, antifibrotic agents may offer new avenues of treatment for patients with SSc-ILD in the future.

A Role of Myocardin Related Transcription Factor-A (MRTF-A) in Scleroderma Related Fibrosis

In scleroderma (systemic sclerosis, SSc), persistent activation of myofibroblast leads to severe skin and organ fibrosis resistant to therapy. Increased mechanical stiffness in the involved fibrotic tissues is a hallmark clinical feature and a cause of disabling symptoms. Myocardin Related Transcription Factor-A (MRTF-A) is a transcriptional co-activator that is sequestered in the cytoplasm and translocates to the nucleus under mechanical stress or growth factor stimulation. Our objective was to determine if MRTF-A is activated in the disease microenvironment to produce more extracellular matrix in progressive SSc. Immunohistochemistry studies demonstrate that nuclear translocation of MRTF-A in scleroderma tissues occurs in keratinocytes, endothelial cells, infiltrating inflammatory cells, and dermal fibroblasts, consistent with enhanced signaling in multiple cell lineages exposed to the stiff extracellular matrix. Inhibition of MRTF-A nuclear translocation or knockdown of MRTF-A synthesis abolishes the SSc myofibroblast enhanced basal contractility and synthesis of type I collagen and inhibits the matricellular profibrotic protein, connective tissue growth factor (CCN2/CTGF). In MRTF-A null mice, basal skin and lung stiffness was abnormally reduced and associated with altered fibrillar collagen. MRTF-A has a role in SSc fibrosis acting as a central regulator linking mechanical cues to adverse remodeling of the extracellular matrix.