Premium
Reduction of Kir4.1 channel activity in an oxidative stress‐related aging model
Author(s) -
Remigante Alessia,
Morabito Rossana,
Marino Angela,
Scimemi Pietro,
Picco Cristiana,
Santarelli Rosamaria,
Zifarelli Giovanni,
Dossena Silvia,
Pusch Michael
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.01854
Subject(s) - oxidative stress , chemistry , endocochlear potential , neurodegeneration , transactivation , microbiology and biotechnology , endocrinology , medicine , homeostasis , cochlea , biology , biochemistry , neuroscience , gene expression , disease , gene
Aging is a major risk factor for many chronic diseases that predisposes to impairment of cellular function via several mechanisms, including oxidative stress (OS) which exerts its action on plasma membrane and transport systems, affecting thus cell homeostasis. Among experimental aging models, D‐galactose (D‐gal) exposure is the most similar to naturally aging, and though several studies have correlated oxidative stress to neurodegeneration, the link between aging, OS, and typical elderly‐related disturbances, such as age‐related hearing loss, is still unclear. Age‐related hearing loss is characterized by a gradual decline of hearing sensitivity. The inward rectifier K + channel Kir4.1 is expressed in the cochlea, where it is very important for endocochlear potential generation and maintenance, ensuring high K + levels in the endolymph. In the present study, we investigated the effect of D‐gal induced aging on Kir4.1 channel function in glioblastoma U87‐MG cells. Kir4.1 is uniformly expressed in U87‐MG cells, and this cell line represent a suitable model to mimic endogenous expression of Kir4.1 in the intermediate cells of the stria vascularis. D‐galactose treatment did not reduce cell viability, indicating that D‐gal at concentrations of 30 and 100 mM for 24 hours had no obvious cytotoxicity. In addition, D‐gal exposure results in the activation of OS pathways, namely 100 mM D‐gal significantly enhanced TBARS levels, and altered the membrane sulfhydryl groups. Interestingly, 100 mM D‐gal exposure was associated with a pronounced decrease of Ba 2+ sensitive inwardly rectifying K + currents, probably mediated by Kir4.1 (p<0.05, n=6). Importantly, treatment with 100 mM mannitol had no significant effect on the Ba 2+ sensitive K + current (n=6). A lower concentration of D‐gal (30 mM) failed to modify the Ba 2+ sensitive K + current. In parallel, to verify that the effect of D‐gal on Kir4.1 was mediated by an increase in OS, the effect of the oxidizing agent (TBH70X) was also investigated. Exposure for 5 minutes or the incubation with 1 mM TBH70X for 2 hours significantly reduced Ba 2+ sensitive K + currents compared to control. In conclusion, these preliminary findings establish a new model for analyzing aging in glioblastoma cells, suggesting thus a potential novel Kir4.1 channel modulation mechanism that is likely to occur in oxidative stress.