Activation of JNK signaling promotes all-trans-retinal-induced photoreceptor apoptosis in mice.
J Biol Chem
; 295(20): 6958-6971, 2020 05 15.
Article
de En
| MEDLINE
| ID: mdl-32265302
ABSTRACT
Disrupted clearance of all-trans-retinal (atRAL), a component of the visual (retinoid) cycle in the retina, may cause photoreceptor atrophy in autosomal recessive Stargardt disease (STGD1) and dry age-related macular degeneration (AMD). However, the mechanisms underlying atRAL-induced photoreceptor loss remain elusive. Here, we report that atRAL activates c-Jun N-terminal kinase (JNK) signaling at least partially through reactive oxygen species production, which promoted mitochondria-mediated caspase- and DNA damage-dependent apoptosis in photoreceptor cells. Damage to mitochondria in atRAL-exposed photoreceptor cells resulted from JNK activation, leading to decreased expression of Bcl2 apoptosis regulator (Bcl2), increased Bcl2 antagonist/killer (Bak) levels, and cytochrome c (Cyt c) release into the cytosol. Cytosolic Cyt c specifically provoked caspase-9 and caspase-3 activation and thereby initiated apoptosis. Phosphorylation of JNK in atRAL-loaded photoreceptor cells induced the appearance of γH2AX, a sensitive marker for DNA damage, and was also associated with apoptosis onset. Suppression of JNK signaling protected photoreceptor cells against atRAL-induced apoptosis. Moreover, photoreceptor cells lacking Jnk1 and Jnk2 genes were more resistant to atRAL-associated cytotoxicity. The Abca4-/-Rdh8-/- mouse model displays defects in atRAL clearance that are characteristic of STGD1 and dry AMD. We found that JNK signaling was activated in the neural retina of light-exposed Abca4-/-Rdh8-/- mice. Of note, intraperitoneal administration of JNK-IN-8, which inhibits JNK signaling, effectively ameliorated photoreceptor degeneration and apoptosis in light-exposed Abca4-/-Rdh8-/- mice. We propose that pharmacological inhibition of JNK signaling may represent a therapeutic strategy for preventing photoreceptor loss in retinopathies arising from atRAL overload.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Rétinal
/
Transduction du signal
/
Apoptose
/
Cellules photoréceptrices de vertébré
/
Mitogen-Activated Protein Kinase 8
/
Mitogen-Activated Protein Kinase 9
/
Maladie de Stargardt
Type d'étude:
Prognostic_studies
Limites:
Animals
Langue:
En
Journal:
J Biol Chem
Année:
2020
Type de document:
Article
Pays d'affiliation:
Chine