*2.1. Cell Cultures*

Primary vascular smooth muscle cells (VSMCs) were isolated from the aorta of male normotensive Wistar rats (200 to 220 g; Charles River Laboratories Germany GmbH) as previously described [24]. Briefly, under dissecting microscope fat, connective tissue and outgoing arteries were removed from the aorta. The vessel was cut longitudinally, and the endothelium was removed with a cell scraper by gentle scraping along the luminal face. VSMCs were isolated by using digestion method, cultured and frozen in liquid nitrogen.

The cells were identified by "hill and valley" growth pattern and immunofluorescence staining with an anti-smooth muscle actin monoclonal antibody (Merk KGaA, Darmstadt, Germany). VSMCs were cultured in Dulbecco's modified Eagle's medium (4.5 g/L glucose) supplemented with 10% fetal bovine serum. Experiments were performed with cultures from passages 4 to 12.

This study was carried out in strict accordance with national and European guidelines for animal experiments with approval by the ethics commission of the regulatory authorities of the City of Berlin, Germany, the "Landesamt for Gesundheit und Soziales" (registration number G0002/16).

Neonatal rat cardiomyocytes (H9c2 cell line, 88092904, Sigmaaldrich, Merk, Germany) are a subclone of the original clonal cell line derived from embryonic BD1X rat heart tissue that exhibit many of the properties of skeletal muscle. The cells were incubated in highglucose Dulbecco's modified Eagle's medium with 10% fetal bovine serum. Cell splitting was performed when H9c2 cells reached confluence.

#### *2.2. Cell Culture Experiments*

Confluent cells were serum-deprived for 24 h. The cells were exposed to recombinant interleukin-1 α (IL-1 α) 1.0 ng/mL (Sigma-Aldrich, Taufkirchen, Germany) to induce secretion of MMPs. Incubation was performed with or without added compounds for 48 h. The following CB1R and CB2R agonists and antagonists were used: CB1R agonist arachidonyl-2-chloroethylamide (ACEA) (0.5 μM), CB1R antagonist rimonabant (1.0 μM), CB2R agonist JWH133 (0.5 μM) and CB2R antagonist 6-Iodopravadoline (AM630) (1.0 μM). Epigallocatechin gallate (ECEG) (5 μg/mL), an inhibitor of MMPs, was used as a positive control. Conditioned media were obtained by collecting the culture media at the end of the experiment. Proteins were extracted from the cells and processed for Western blot analysis.
