nrf2 is placed downstream of pgc1a and due to high expression of pgc1a in the heart, nrf2 is expected to expressed, as well. you would better search literature.
I think all the cells express Nrf2 gene. Since Nrf2 is a master transcription factor regulated expression of many cytoprotective genes. The important point is that this transcription factor is regulated at protein level and in normal condition Nrf2 protein is immediately degraded by ubiquitination.