Cyclophilin A/EMMPRIN Axis Is Involved in Pro-Fibrotic Processes Associated with Thoracic Aortic Aneurysm of Marfan Syndrome Patients

Background: Marfan syndrome (MFS) is a genetic disease, characterized by thoracic aortic aneurysm (TAA), which treatment is to date purely surgical. Understanding of novel molecular targets is mandatory to unveil effective pharmacological approaches. Cyclophilin A (CyPA) and its receptor EMMPRIN are associated with several cardiovascular diseases, including abdominal aortic aneurysm. Here, we envisioned the contribution of CyPA/EMMPRIN axis in MFS-related TAA. METHODS: We obtained thoracic aortic samples from healthy controls (HC) and MFS patients' aortas and then isolated vascular smooth muscle cells (VSMC) from the aortic wall. RESULTS: our findings revealed that MFS aortic tissue samples isolated from the dilated zone of aorta showed higher expression levels of EMMPRIN vs. MFS non-dilated aorta and HC. Interestingly, angiotensin II significantly stimulated CyPA secretion in MFS-derived VSMC (MFS-VSMC). CyPA treatment on MFS-VSMC led to increased levels of EMMPRIN and other MFS-associated pro-fibrotic mediators, such as TGF-\u3b21 and collagen I. These molecules were downregulated by in vitro treatment with CyPA inhibitor MM284. Our results suggest that CyPA/EMMPRIN axis is involved in MFS-related TAA development, since EMMPRIN is upregulated in the dilated zone of MFS patients' TAA and the inhibition of its ligand, CyPA, downregulated EMMPRIN and MFS-related markers in MFS-VSMC. CONCLUSIONS: these insights suggest both a novel detrimental role for CyPA/EMMPRIN axis and its inhibition as a potential therapeutic strategy for MFS-related TAA treatment

Integrin ανβ5 in vitro inhibition limits pro-fibrotic response in cardiac fibroblasts of spontaneously hypertensive rats

BackgroundTo date the TGF-1 activation mediated by integrin 5 during fibrosis is well-known. This process has been shown also in the heart, where cardiac fibroblasts (CF) differentiate into -smooth muscle actin (-SMA)-positive myofibroblasts (MyoFB). Here, we studied the effects on CF, isolated by spontaneously hypertensive rats (SHR), of integrin 5 inhibition in MyoFB differentiation.MethodsStaining and immunohistochemistry were performed on rat cardiac tissue. CF were isolated by enzymatic digestion from SHR (SHR-CF) and normotensive WKY (WKY-CF) rat hearts and then treated for in vitro evaluation.ResultsSHR heart tissues revealed a higher TGF-1 expression vs. WKY samples. SHR-CF showed an enhanced SMAD2/3 activation and an up-regulated expression of -SMA, a typical MyoFB marker, especially after TGF-1 treatment. Immunostaining on cardiac tissues revealed a higher expression of integrin 5 in SHR vs. WKY rat hearts. In vitro results confirmed the up-regulation of integrin 5 expression in SHR-CF at basal condition and after TGF-1 treatment, in comparison with WKY-CF. Inhibition of integrin 5 by cilengitide treatment led a decreased expression of 5, collagen I, and -SMA in SHR-CF vs. WKY-CF, resulting in a diminished differentiation of CF into MyoFB. Taking together, results suggested that SHR-CF are more susceptible to TGF-1, showing an up-regulated activation of SMAD2/3 signaling, and an increased 5, -SMA, and collagen I expression. Hypertension stimulus promoted an up-regulation of integrin 5 on SHR cardiac tissue and its in vitro inhibition reverted pro-fibrotic events of SHR-CF.ConclusionInhibition of integrin 5 exerted by cilengitide strongly diminished SHR-CF differentiation into detrimental MyoFB. So, integrin 5 might be considered a novel therapeutic target and cilengitide an effective pharmacological tool to limit the progression of hypertension-induced cardiac fibrosis