TY - JOUR
T1 - Identification of p38 MAPK and JNK as New Targets for Correction of Wilson Disease-Causing ATP7B Mutants
AU - Chesi, Giancarlo
AU - Hegde, Ramanath N.
AU - Iacobacci, Simona
AU - Concilli, Mafalda
AU - Parashuraman, Seetharaman
AU - Festa, Beatrice Paola
AU - Polishchuk, Elena V.
AU - Di Tullio, Giuseppe
AU - Carissimo, Annamaria
AU - Montefusco, Sandro
AU - Canetti, Diana
AU - Monti, Maria
AU - Amoresano, Angela
AU - Pucci, Piero
AU - Sluis, van de, Bart
AU - Lutsenko, Svetlana
AU - Luini, Alberto
AU - Polishchuk, Roman S.
PY - 2016/6
Y1 - 2016/6
N2 - Wilson disease (WD) is an autosomal recessive disorder that is caused by the toxic accumulation of copper (Cu) in the liver. The ATP7B gene, which is mutated in WD, encodes a multitransmembrane domain adenosine triphosphatase that traffics from the trans-Golgi network to the canalicular area of hepatocytes, where it facilitates excretion of excess Cu into the bile. Several ATP7B mutations, including H1069Q and R778L that are two of the most frequent variants, result in protein products, which, although still functional, remain in the endoplasmic reticulum. Thus, they fail to reach Cu excretion sites, resulting in the toxic buildup of Cu in the liver of WD patients. Therefore, correcting the location of these mutants by leading them to the appropriate functional sites in the cell should restore Cu excretion and would be beneficial to help large cohorts of WD patients. However, molecular targets for correction of endoplasmic reticulum-retained ATP7B mutants remain elusive. Here, we show that expression of the most frequent ATP7B mutant, H1069Q, activates p38 and c-Jun N-terminal kinase signaling pathways, which favor the rapid degradation of the mutant. Suppression of these pathways with RNA interference or specific chemical inhibitors results in the substantial rescue of ATP7B(H1069Q) (as well as that of several other WD-causing mutants) from the endoplasmic reticulum to the trans-Golgi network compartment, in recovery of its Cu-dependent trafficking, and in reduction of intracellular Cu levels. Conclusion: Our findings indicate p38 and c-Jun N-terminal kinase as intriguing targets for correction of WD-causing mutants and, hence, as potential candidates, which could be evaluated for the development of novel therapeutic strategies to combat WD.
AB - Wilson disease (WD) is an autosomal recessive disorder that is caused by the toxic accumulation of copper (Cu) in the liver. The ATP7B gene, which is mutated in WD, encodes a multitransmembrane domain adenosine triphosphatase that traffics from the trans-Golgi network to the canalicular area of hepatocytes, where it facilitates excretion of excess Cu into the bile. Several ATP7B mutations, including H1069Q and R778L that are two of the most frequent variants, result in protein products, which, although still functional, remain in the endoplasmic reticulum. Thus, they fail to reach Cu excretion sites, resulting in the toxic buildup of Cu in the liver of WD patients. Therefore, correcting the location of these mutants by leading them to the appropriate functional sites in the cell should restore Cu excretion and would be beneficial to help large cohorts of WD patients. However, molecular targets for correction of endoplasmic reticulum-retained ATP7B mutants remain elusive. Here, we show that expression of the most frequent ATP7B mutant, H1069Q, activates p38 and c-Jun N-terminal kinase signaling pathways, which favor the rapid degradation of the mutant. Suppression of these pathways with RNA interference or specific chemical inhibitors results in the substantial rescue of ATP7B(H1069Q) (as well as that of several other WD-causing mutants) from the endoplasmic reticulum to the trans-Golgi network compartment, in recovery of its Cu-dependent trafficking, and in reduction of intracellular Cu levels. Conclusion: Our findings indicate p38 and c-Jun N-terminal kinase as intriguing targets for correction of WD-causing mutants and, hence, as potential candidates, which could be evaluated for the development of novel therapeutic strategies to combat WD.
KW - COPPER HOMEOSTASIS
KW - CYSTIC-FIBROSIS
KW - PROTEIN ATP7B
KW - EXPRESSION
KW - MUTATIONS
KW - KINASE
KW - CELLS
KW - TRAFFICKING
KW - COMPLEXES
KW - APOPTOSIS
U2 - 10.1002/hep.28398
DO - 10.1002/hep.28398
M3 - Article
SN - 0270-9139
VL - 63
SP - 1842
EP - 1859
JO - Hepatology
JF - Hepatology
IS - 6
ER -