Data in support of sustained upregulation of adaptive redox homeostasis mechanisms caused by KRIT1 loss-of-function

Abstract

This article contains additional data related to the original research article entitled “KRIT1 loss-of-function induces a chronic Nrf2-mediated adaptive homeostasis that sensitizes cells to oxidative stress: implication for Cerebral Cavernous Malformation disease” (Antognelli et al., 2017) [1].Data were obtained by si-RNA-mediated gene silencing, qRT-PCR, immunoblotting, and immunohistochemistry studies, and enzymatic activity and apoptosis assays. Overall, they support, complement and extend original findings demonstrating that KRIT1 loss-of-function induces a redox-sensitive and JNK-dependent sustained upregulation of the master Nrf2 antioxidant defense pathway and its downstream target Glyoxalase 1 (Glo1), and a drop in intracellular levels of AP-modified Hsp70 and Hsp27 proteins, leading to a chronic adaptive redox homeostasis that sensitizes cells to oxidative DNA damage and apoptosis.In particular, immunoblotting analyses of Nrf2, Glo1, AP-modified Hsp70 and Hsp27 proteins, HO-1, phospho-c-Jun, phospho-ERK5, and KLF4 expression levels were performed both in KRIT1-knockout MEF cells and in KRIT1-silenced human brain microvascular endothelial cells (hBMEC) treated with the antioxidant Tiron, and compared with control cells. Moreover, immunohistochemistry analysis of Nrf2, Glo1, phospho-JNK, and KLF4 was performed on histological samples of human CCM lesions. Finally, the role of Glo1 in the downregulation of AP-modified Hsp70 and Hsp27 proteins, and the increase in apoptosis susceptibility associated with KRIT1 loss-of-function was addressed by si-RNA-mediated Glo1 gene silencing in KRIT1-knockout MEF cells. Keywords: Cerebrovascular disease, Cerebral cavernous malformations, CCM1/KRIT1, Oxidative stress, Antioxidant defense, Adaptive redox homeostasis, Redox signaling, Nuclear factor erythroid 2-related factor 2 (Nrf2), c-Jun, Glyoxalase 1 (Glo1), Heme oxygenase-1 (HO-1), Argpyrimidine-modified heat-shock proteins, Oxidative DNA damage and apoptosis