Smith et al. (2006) found that in granulation-tissue fibroblasts from periodontal disease tissues, JNK was activated by TGFβ1 and stimulated uPA production; the JNK inhibitor, SP600125, completely attenuated the stimulus of TGFβ1 on uPA production in a dose-dependent manner [116]. Here, MAPK8 is linked to periodontal disorder.