Fig. 4: PARP12 negatively regulates TGF-β1 expression through FHL2.

a PARP12 deficiency increased the transcription of TGF-β1. The mRNA levels of TGF-β1 in PARP12 wild-type or -deficient cells were analyzed by RT-qPCR. **P < 0.01, ****P < 0.0001. b PARP12 deficiency increased the TGF-β1 level in cell culture medium. The TGF-β1 levels in the cell culture mediums of PARP12 wild-type or -deficient cells were analyzed by ELISA. **P < 0.01, ***P < 0.001. c Wild-type and enzyme-inactive mutant PARP12-reconstitutions decreased the transcription of TGF-β1 in PARP12-deficient cells. The mRNA levels of TGF-β1 in PARP12 wild-type, -deficient, and -reconstituted cells were analyzed by RT-qPCR. **P < 0.01, ***P < 0.001, ****P < 0.0001. d Wild-type and enzyme-inactive mutant PARP12 reconstitutions decreased the TGF-β1 level in PARP12-deficient cell culture medium. The TGF-β1 levels in PARP12 wild-type, -deficient, and -reconstituted cell culture mediums were analyzed by ELISA. ***P < 0.001, ****P < 0.0001. e PARP12 regulated TGF-β1 expression dependent on FHL2. FHL2 was overexpressed in PARP12-deficient QGY-7703 cells, and the expression level was examined by Western blot using the indicated antibodies. f, g The mRNA levels of TGF-β1 and the secretory TGF-β1 levels in wild-type, PARP12-deficient, and FHL2-overexpressed PARP12-deficient cells were analyzed by RT-qPCR and ELISA, respectively. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001