Loss of Thy-1 may reduce lung regeneration after pneumonectomy in mice.

BACKGROUND: Lung regeneration plays an important role in lung repair after injury. It is reliant upon proliferation of multiple cell types in the lung, including endothelium, epithelium, and fibroblasts, as well as remodeling of the extracellular matrix.

METHODS: Lung regeneration following injury progresses via an initial inflammatory response during which macrophages clear the tissue of cellular debris. This process continues through cellular proliferation when existing cells and progenitors act to repopulate cells lost during injury, followed by tissue maturation in which newly formed cells achieve a differentiated phenotype.

RESULTS: Signaling pathways critical for lung regeneration include FGF, EGF, WNT, and NOTCH. In addition, HDACs, miRNAs, ELASTIN, and MMP14 have been shown to regulate lung regeneration. Partial pneumonectomy (PNX) has been used as a therapeutic and investigational tool for several decades. Following PNX the remaining lung increases in size to compensate for loss of volume and respiratory capacity.

CONCLUSIONS: Much has been learned about the triggers and mechanisms regulating pulmonary regeneration. However, the role of thymocyte differentiation antigen-1 (Thy-1) in post-PNX lung growth remains incompletely characterized. Thy-1 is a phosphatidylinositol glycoprotein with a relative molecular weight of 25000~37000 Da, which is expressed in almost all types of fibroblasts and regulates many biological functions. It not only supports the structure of fibroblasts, but also can balance cell proliferation, migration and regulate the synthesis of immune inflammatory mediators.