rottlerin and proxymetacaine

Protein kinase C (PKC)-delta, an upstream regulator of the Akt survival pathway, contributes to cellular dysfunction in the pathogenesis of diabetes. Herein, we examined the role of PKC-delta in neuronal apoptosis through Akt in the retinas of diabetic rats.. We used retinas from 24- and 35-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) diabetic and Long-Evans Tokushima Otsuka (LETO) nondiabetic rats. To assess whether PKC-delta affects Akt signaling and cell death in OLETF rat retinas, we examined 1) PKC-delta activity and apoptosis; 2) protein levels of phosphatidylinositol 3-kinase (PI 3-kinase) p85, heat shock protein 90 (HSP90), and protein phosphatase 2A (PP2A); 3) Akt phosphorylation; and 4) Akt binding to HSP90 or PP2A in LETO and OLETF retinas in the presence or absence of rottlerin, a highly specific PKC-delta inhibitor, or small interfering RNAs (siRNAs) for PKC-delta and HSP90.. In OLETF retinas from 35-week-old rats, ganglion cell death, PKC-delta and PP2A activity, and Akt-PP2A binding were significantly increased and Akt phosphorylation and Akt-HSP90 binding were decreased compared with retinas from 24-week-old OLETF and LETO rats. Rottlerin and PKC-delta siRNA abrogated these effects in OLETF retinas from 35-week-old rats. HSP90 siRNA significantly increased ganglion cell death and Akt-PP2A complexes and markedly decreased HSP90-Akt binding and Akt phosphorylation in LETO retinas from 35-week-old rats compared with those from nontreated LETO rats.. PKC-delta activation contributes to neuro-retinal apoptosis in diabetic rats by inhibiting Akt-mediated signaling pathways.

Topics: Acetophenones; Animals; Apoptosis; Benzopyrans; Body Weight; Diabetes Mellitus, Type 2; HSP90 Heat-Shock Proteins; Immunoblotting; Immunohistochemistry; Immunoprecipitation; In Situ Nick-End Labeling; Male; Neurons; Pentobarbital; Phosphatidylinositol 3-Kinases; Propoxycaine; Protein Binding; Protein Kinase C-delta; Protein Phosphatase 2; Proto-Oncogene Proteins c-akt; Rats; Rats, Inbred OLETF; Retina; Retinal Ganglion Cells; RNA, Small Interfering; Signal Transduction