TGM2 and neurodegenerative disease: HMOX1 is upregulated in epileptic rats (Wang et al., 2013; Prakash et al., 2019), and previous studies have found that tissue-type transglutaminase (TGM2) is mostly produced by neurons in the mammalian nervous system and is elevated in neurodegenerative diseases as well as in response to acute CNS injury, which possibly induces neuronal cell death (Tucholski et al., 2006).