Fig 2: Inhibition of S1PR2 by JTE013 blunted acute aortic dissection (AAD) formation and prevent aortic rupture. (A) Representative morphology of the aortas in each group. (B) The JTE013 treatment attenuated AAD formation and prevent aortic rupture. (C) Representative images of hematoxylin and eosin staining and elastin-van gieson elastin staining of aorta lesions. (D) Elastic fiber fragmentation grade analysis (n = 6). (E) Representative images of Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) (red) and a-SMA (green) double-immunofluorescence staining area. (F) JTE013 treatment resulted in a restraint of SMCs apoptosis level (n = 3). Scale: 200 µm or 50 µm. Data are expressed as means ± SD.

Fig 3: Inhibition of S1PR2 by JTE013 reduced inflammatory infiltration and angiogenesis. (A,E) Lesion CD4+ T-cell numbers and corresponding analysis. (B,F) Lesion CD8+ T-cell numbers and corresponding analysis. (C,G) Lesion MPO+ neutrophil numbers and corresponding analysis. (D,H) Lesion CD31+ micro-vessel numbers and corresponding analysis. (I) RT-qPCR determined lesion mRNA levels of IL-1ß, IL-6, MCP-1, TNF-a, E-selectin, ICAM-1, VCAM-1, CXCL-2, and CXCL-5. (J,K) Analysis of MMP2 and MMP9 mRNA expression. n = 6 mice per group. ***p < 0.001 vs. the vehicle group. Scale: 200 µm, inset: 50 µm. Data are expressed as means ± SD. Myeloperoxidase (MPO), a marker for neutrophil abundance.

Fig 4: Activated S1P/S1PR2 signaling and neutrophil extracellular traps (NETs) had a positive correlation. (A,B) Immunofluorescent staining showing the colocalization of S1PR2 and NETs in human and mouse TAD lesions. (C–E) Representative immunoblot and the corresponding analysis of human SPHK1 and CitH3 in TAD lesions (n = 10) and normal thoracic aorta (n = 6). (F,G) Serum S1P and CitH3 levels in the matched control (n = 55), patients with TAD before surgery (n = 67) and TAD patients after surgery (n = 58). (H) SPHK1 protein level positively correlated with CitH3 protein level in patients with TAD. (I) Serum S1P level positively correlated with serum CitH3 level in patients with TAD. Scale: 100 µm or 20 µm. Data are expressed as means ± SD. CitH3, a specific marker of NETs; Myeloperoxidase (MPO), a marker for neutrophil abundance.

Fig 5: Inhibition of S1PR2 by JTE013 reduced NETs accumulation. (A) Representative images of CitH3+ (green) MPO+ (red) double-immunofluorescence staining NETs area in mouse TAD lesions from each group. (B) The JTE013 treatment diminished NETs density (n = 4). (C–E) Representative immunoblot and the corresponding analysis of mouse CitH3 and SPHK1 in each group (n = 6). (F,G) JTE013 treatment reduced serum CitH3 and S1P levels (n = 6). Scale: 50 µm. Data are expressed as means ± SD. CitH3, a specific marker of NETs; MPO, a marker for neutrophil abundance.