Maresin 1

Mouse glomerular mesangial cells (GMCs) were purchased from Chinese Academy of Sciences and cultured in low glucose Dulbecco's Modified Eagle Medium (DMEM, Hyclone, USA) with 10% fetal bovine serum (FBS, BOVOGEN, Australia) at 37°C and 5% CO₂. GMCs were used between the 2nd and 5th passages for all experiments. To observe the effect of maresin 1, we divided the cells into 8 groups: ① normal control group (NC group): 5.6 mmol/L glucose, ② osmotic pressure control group (OP group): 5.6 mmol/L glucose + 24.4 mmol/L mannitol, ③ high glucose group (HG group): 30 mmol/L glucose, ④ different concentrations of maresin 1 + high glucose group (M + HG group): the GMCs being treated with different concentration of maresin 1 (1, 10, and 100 nmol/L, Cayman Chemical, USA) for 30 min before being exposed to high glucose (30 mmol/L) [22 (link), 23 (link)], 1 nmol/L maresin 1 + 30 mmol/L glucose (M1 + HG group), 10 nmol/L maresin 1 + 30 mmol/L glucose (M2 + HG group), 100 nmol/L maresin 1 + 30 mmol/L glucose (M3 + HG group), ⑤ maresin 1 + normal control group (M + NC group): the most obvious effect of maresin 1 concentration + 5.6 mmol/L glucose, ⑥ N-acetylcysteine (NAC) intervention group as positive control (10 μmol/L NAC + HG group) [24 (link), 25 (link)]. Each test was independently repeated more than 3 times.

Maresin‐1 and Maresin‐1 ELISA kit were purchased from Cayman Chemical. AngII was purchased from Enzo Life Sciences. Mouse IL‐1β ELISA kit was purchased from Neobioscience. EdU imaging kits was purchased from APExBIO. ML385 and KN‐93 were purchase from Topscience. Fluo‐4 AM was purchased from Invitrogen. Fetal bovine serum was purchased from Inner Mongolia Opcel Biotechnology Co., Ltd. Primary antibodies included: anti‐GAPDH (Abcolonal), anti‐SM22α (Servicebio), anti‐ASC (Santa Cruz Biotechnology), anti‐caspase‐1 p20 (Santa Cruz Biotechnology), anti‐IL‐1β (Santa Cruz Biotechnology), anti‐OPN (Immunoway), anti‐NLRP3 (Immunoway), anti‐IL‐18 (ImmunoWay), anti‐GSDMD‐N (Immunoway), anti‐Nrf2 (GeneTex), anti‐α‐SMA(Abcam), anti‐HO‐1(Abcam), anti‐CaMKII (Abcam), anti‐p‐CaMKII (Zenbio), anti‐PCNA (Cell Signaling Technology), anti‐rabbit IgG (H+L) (Cell Signaling Technology), anti‐mouse IgG (H+L) (Cell Signaling Technology), Cy3‐conjugated goat anti‐rabbit IgG (H+L) (Servicebio), and Alexa Fluor® 488‐conjugated goat anti‐rabbit IgG (H+L) (Servicebio).

Tendon stromal cells were derived from diseased supraspinatus tendons. Cells were seeded at a density of 60,000 cells per well in 6 well plates for SPM profiles, (6 donors). Once cells were at 80% confluence, they were pre-incubated in 10μM indomethacin (Sigma) or 25μM 15-PGDH inhibitor (SW033291, Tocris) in DMEM F12 phenol red free medium containing 1% heat inactivated human serum and 1% penicillin-streptomycin. After 2 h, 10 nM 15-epi Lipoxin A₄ (Cayman Chemical) or 10 nM Maresin 1 (Cayman Chemical) were added and cells further incubated for 24 h. Healthy and diseased cells were then stimulated with IL-1β (10ngml^—1), non-treated (vehicle only) IL-1β stimulated cells served as controls for each experiment. Cells were shielded from light and incubated at 37 °C and 5% CO₂ until harvest of the media and lysate for bioactive lipid mediator profiling 24 h after stimulation with IL-1β.

Maresin1 (7,14-dihydroxydocosa-4Z,8Z,10,12,16Z,19Z-hexaenoic acid, MaR1) was from Cayman Chemical Company (Ann Arbor, MI, USA). The chemical structure of MaR1 is shown in Figure 1(a). TNF-α and IL-6 ELISA kits were from R&D Systems (Minneapolis, MN, USA). Blood biochemistry assay kits (ALT/AST) were from Jiancheng Bioengineering Institute (Nanjing, Jiangsu, China).