Plasminogen activator inhibitor-1 reduces cardiac fibrosis and promotes M2 macrophage polarization in inflammatory cardiomyopathy

Abstract

Plasminogen activator inhibitor-1 (PAI-1) has a cardioprotective function in mice by repressing cardiac fibrosis through TGF-β and plasminogen-mediated pathways. In addition it is known to be involved in the recruitment and polarization of monocytes/macrophages towards a M2 phenotype in cancer. Here, we investigated the expression of PAI-1 in human dilated cardiomyopathy (DCM) and inflammatory dilated cardiomyopathy (DCMi) and its effect on cardiac fibrosis and macrophage polarization. We retrospectively analyzed endomyocardial biopsies (EMBs) of patients with DCM or DCMi for PAI-1 expression by immunohistochemistry. Furthermore, EMBs were evaluated for the content of fibrotic tissue, number of activated myofibroblasts, TGF-β expression, as well as for M1 and M2 macrophages. Patients with high-grade DCMi (DCMi-high, CD3+ lymphocytes > 30 cells/mm2) had significantly increased PAI-1 levels compared to DCM and low-grade DCMi patients (DCMi-low, CD3+ lymphocytes = 14–30 cells/mm2) (15.5 ± 0.4% vs. 1.0 ± 0.1% and 4.0 ± 0.1%, p ≤ 0.001). Elevated PAI-1 expression in DCMi-high subjects was associated with a diminished degree of cardiac fibrosis, decreased levels of TGF-β and reduced number of myofibroblasts. In addition, DCMi-high patients revealed an increased proportion of non-classical M2 macrophages towards classical M1 macrophages, indicating M2 macrophage-favoring properties of PAI-1 in inflammatory cardiomyopathies. Our findings give evidence that elevated expression of cardiac PAI-1 in subjects with high-grade DCMi suppresses fibrosis by inhibiting TGF-β and myofibroblast activation. Moreover, our data indicate that PAI-1 is involved in the polarization of M2 macrophages in the heart. Thus, PAI-1 could serve as a potential prognostic biomarker and as a possible therapeutic target in inflammatory cardiomyopathies.

Extracellular Vesicle/Macrophage Axis: Potential Targets for Inflammatory Disease Intervention

“…In the myocardial injury stage of dilated cardiomyopathy, large numbers of macrophages are recruited to the injured site, accounting for 75% of all infiltrating cells. Under the influence of the cardiac microenvironment, macrophages are mainly polarized to an M1-like phenotype and participate in the immune response of diseases ( 82 ). Studies by researchers have applied echocardiography and hematoxylin-eosin (HE) staining of the heart, and the results showed that myocardial diastolic function was significantly improved, the proportion of apoptotic myocardial cells was significantly reduced, and the expression level of inflammatory factors was reduced in the MSC-derived EVs treatment group compared with the normal group.…”

Optimization of High-Throughput Multiplexed Phenotyping of Extracellular Vesicles Performed in 96-Well Microtiter Plates

“…The ability for the EV Array to capture sEVs in a quantitative manner have previously been proven within other works, where detailed molecular analyses of the sEVs were performed by nanotracking analysis (NTA) [ 12 ], transmission electron microscopy (TEM) [ 16 , 17 ], and western blotting [ 18 ]. The scope of this study was to optimize an already established and verified technology, which is why we chose not to focus on the EV characteristics despite the recommendations by the MISEV guidelines [ 9 ].…”

Angiotensin II Induces Oxidative Stress and Endothelial Dysfunction in Mouse Ophthalmic Arteries via Involvement of AT1 Receptors and NOX2

“…Freshly prepared cryosections (10 µm thickness) were incubated with 1 μM of dihydroethidium (DHE, Thermo Fischer Scientific, Waltham, MA, USA) for 30 min at 37 °C. By using an Eclipse TS 100 microscope (Nikon, Yurakucho, Tokyo, Japan) equipped with a DS–Fi1-U2 digital microscope camera (Nikon) and the imaging software NIS Elements (Nikon, Version 1.10 64 bit) the fluorescence (518 nm/605 nm excitation/emission) was recorded and measured in the vascular wall by using ImageJ (NIH, ) accessed on 11 March 2019 [ 43 , 44 ].…”