High glucose induces an early and transient cytoprotective autophagy in retinal Müller cells

Purpose We investigated the autophagic response of rat Müller rMC-1 cells during a short-term high glucose challenge. Methods rMC-1 cells were maintained in 5 mM glucose (LG) or exposed to 25 mM glucose (HG). Western blot analysis was used to evaluate the expression levels of markers of autophagy (L...

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Bibliographic Details
Published in:Endocrine 2022-08, Vol.77 (2), p.221-230
Main Authors: Mecchia, A., Palumbo, C., De Luca, A., Sbardella, D., Boccaccini, A., Rossi, L., Parravano, M., Varano, M., Caccuri, A. M.
Format: Article
Language:English
Subjects:
AKT protein
Aquaporin 4
Autophagy
Cell viability
Chloroquine
Diabetes
Endocrinology
Flow cytometry
Glucose
Humanities and Social Sciences
Internal Medicine
Medicine
Medicine & Public Health
Mueller cells
multidisciplinary
Original
Original Article
Oxidative stress
Science
TRAF2 protein
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Summary:Purpose We investigated the autophagic response of rat Müller rMC-1 cells during a short-term high glucose challenge. Methods rMC-1 cells were maintained in 5 mM glucose (LG) or exposed to 25 mM glucose (HG). Western blot analysis was used to evaluate the expression levels of markers of autophagy (LC3-II, p62) and glial activation (AQP4), as well as the activation of TRAF2/JNK, ERK and AKT pathways. Autophagic flux assessment was performed using the autophagy inhibitor chloroquine. ROS levels were measured by flow cytometry using dichlorofluorescein diacetate. ERK involvement in autophagy induction was addressed using the ERK inhibitor FR180204. The effect of autophagy inhibition on cell viability was evaluated by SRB assay. Results Activation of autophagy was observed in the first 2–6 h of HG exposure. This early autophagic response was transient, not accompanied by an increase in AQP4 or in the phospho-activation of JNK, a key mediator of cellular response to oxidative stress, and required ERK activity. Cells exposed to HG had a lower viability upon autophagy inhibition by chloroquine, as compared to those maintained in LG. Conclusion A short-term HG challenge triggers in rMC-1 cells a process improving the ability to cope with stressful conditions, which involves ERK and an early and transient autophagy activation.
ISSN:1559-0100
1355-008X
1559-0100
DOI:10.1007/s12020-022-03079-8