Figure 2.

Cardiac fibroblasts protect cardiomyocytes from ferroptosis

(A) Schematic of high cell density protecting tumor cells from ferroptosis.

(B) Schematic showing the change of cardiac cell density during MI.

(C) Survival (negative for trypan blue) rates of iCMs cultured at low, mid, or high density after erastin treatment (15 μM, 5 h).

(D) Survival rates of HCFs cultured at low, mid, or high density after erastin treatment (15 μM, 5 h).

(E and F) PTGS2 (red) and DAPI (blue) were stained and imaged with endogenous TITIN-GFP (green) in iCM after erastin (30 μM) treatment.

(G and H) PTGS2 (red), αSMA (gray), and DAPI (blue) were stained and imaged with endogenous TITIN-GFP (green) in co-cultured iCMs and HCFs after erastin (30 μM) treatment.

(I) Fold change of PTGS2 fluorescent intensity in iCMs and HCFs.

(J–Q) Heart tissue of controls (Postn^MCM/+, J, K, N, O) and Postn^MCM/+;ROSA-DTA (L, M, P, Q) mice were stained for 4-HNE (magenta, J-M) or Ptgs2 (magenta, N-Q) at 4 DPMI after P1 LAD-O; tamoxifen was administered daily at 1–3 DPMI. Green, MF20; blue, DAPI. #, infarct zone. (R) Ratio of cardiomyocytes positive for Ptgs2 or 4-HNE.

(S–V) Heart sections of 2-month-old control (ROSA-DTA, S, T) and Pdgfrα-CreER^T2;ROSA-DTA (U, V) mice stained for 4-HNE (red), cTnT (green), Pdgfrα (gray), and DAPI (blue) after tamoxifen administration (see Figure S3).

(W) Density of Pdgfrα-positive cells in control and mutant groups.

(X) Average 4-HNE intensity in cardiomyocytes from both groups. #, infarct zone. All bar graphs represent mean ± SD. ∗p < 0.05; ∗∗p < 0.01; NS, not significant by t test. NS in (A), no significance among three groups. Scale bar, 50 μm (E–H), 25 μm (J–Q, S–V). See also Figure S3.