Inhibition of cAMP/PKA Pathway Protects Optic Nerve Head Astrocytes against Oxidative Stress by Akt/Bax Phosphorylation-Mediated Mfn1/2 Oligomerization

Figure 7

Effects of PKA inhibition on Mfn1 and Mfn2 oligomerization, and Akt and Bax phosphorylation in ONH astrocytes against combined oxidative stress and cAMP elevation. ONH astrocytes exposed to H₂O₂ (50 μM) were cotreated with dbcAMP (100 μM) and/or H89 (10 μM) for 1 h. (a) Western blot analyses for the oligomerization of Mfn1 and Mfn2 proteins in ONH astrocytes. Note that PKA inhibition induced a significant increase of Mfn1 and Mfn2 protein oligomerization in ONH astrocytes treated with combined H₂O₂ and dbcAMP compared with ONH astrocytes treated with combined H₂O₂ and dbcAMP. (b) Cell viability/mitochondrial activity analysis using MTT assay in ONH astrocytes. Note that PKA inhibition significantly promoted cell viability in ONH astrocytes treated with combined H₂O₂ and dbcAMP compared with ONH astrocytes treated with combined H₂O₂ and dbcAMP. Western blot analyses for the protein expression of pAkt S473 and pBax S184 in ONH astrocytes. Note that PKA inhibition by H89 significantly promoted protein expression of pAkt S473 and pBax S184 in ONH astrocytes treated with combined H₂O₂ and dbcAMP compared with ONH astrocytes treated with combined H₂O₂ and dbcAMP. For each determination, the protein expression in controls was normalized to a value of 1.0. Data are shown as the (). and denote and , respectively.

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