This review highlights molecular mechanisms of anti-inflammatory and protective effects of the nuclear transcription factor, peroxisome proliferator-activated receptor γ (PPARγ) in vascular tissue. PPARγ is an ubiquitously expressed nuclear factor, and well-studied in adipose tissue and inflammatory cells. Additionally, beneficial effects of vascular PPARγ’s on atherosclerosis and vascular remodeling/dysfunction have been reported although the detailed mechanism remains to be completely elucidated. Clinical and basic studies have shown that the synthetic PPARγ ligands, thiazolidinediones (TZDs), have protective effects against cardiovascular diseases such as atherosclerosis. Recent studies utilizing genetic tools suggested that those protective effects of TZDs on cardiovascular diseases are not due to a consequence of improvement of insulin resistance, but may be due to a direct effect on PPARγ’s in vascular endothelial and smooth muscle cells. In this review, we discuss proposed mechanisms by which the vascular PPARγ regulates vascular inflammation and remodeling/dysfunction especially in smooth muscle cells.
Pompe disease is a lysosomal storage disease caused by mutations within the GAA gene, which encodes acid α-glucosidase (GAA)—an enzyme necessary for lysosomal glycogen degradation. A lack of GAA results in an accumulation of glycogen in cardiac and skeletal muscle, as well as in motor neurons. The only FDA approved treatment for Pompe disease—an enzyme replacement therapy (ERT)—increases survival of patients, but has unmasked previously unrecognized clinical manifestations of Pompe disease. These clinical signs and symptoms include tracheo-bronchomalacia, vascular aneurysms, and gastro-intestinal discomfort. Together, these previously unrecognized pathologies indicate that GAA-deficiency impacts smooth muscle in addition to skeletal and cardiac muscle. Thus, we sought to characterize smooth muscle pathology in the airway, vascular, gastrointestinal, and genitourinary in the Gaa−/− mouse model. Increased levels of glycogen were present in smooth muscle cells of the aorta, trachea, esophagus, stomach, and bladder of Gaa−/− mice, compared to wild type mice. In addition, there was an increased abundance of both lysosome membrane protein (LAMP1) and autophagosome membrane protein (LC3) indicating vacuolar accumulation in several tissues. Taken together, we show that GAA deficiency results in subsequent pathology in smooth muscle cells, which may lead to life-threatening complications if not properly treated.