Fig. 6: The effects of hypothalamic PDK2 overexpression on diabetes-induced inflammatory cytokines, food intake, blood glucose, and the expression of hypothalamic neuropeptides in Pdk2 KO mice.

To further determine the role of hypothalamic PDK2 in diabetes-induced neuroinflammation and dysregulation of feeding behavior, we administered Ad-PDK2-GFP or Ad-GFP (1.0 × 109 pfu) via the icv route 1 w before STZ injection. The schematic diagram shows the experimentation timeline and the route of administration (a). PDK2 protein levels (###p = 4.5E-5, KO + Ad-PDK2-GFP + STZ) in the hypothalamus after 3 w of STZ and 4 w of adenovirus injection were assessed by Western blot analysis (b). Western blot band quantification for PDK2 protein levels normalized to α-tubulin. The relative expression of Tnf-α (##p = 0.0030, KO + Ad-PDK2-GFP + STZ), Il-1β (#p = 0.0380, KO + Ad-PDK2-GFP + STZ), and Il-6 (##p = 0.0020, KO + Ad-PDK2-GFP + STZ) mRNA in the hypothalamic tissues isolated from Ad-PDK2-GFP or Ad-GFP and WT mice was evaluated by real-time RT-PCR (c). Food intake (*p = 0.0130, KO + Ad-PDK2-GFP + STZ at 28 d) (d) and fasting blood glucose levels (*p = 0.0127, KO + Ad-PDK2-GFP + STZ at 28 d) (e) were assessed following Ad-PDK2-GFP or Ad-GFP and STZ administration. Arrows indicate the time points of adenovirus (Ad) and STZ administration. The relative expression of Npy (#p = 0.0489, KO + Ad-PDK2-GFP + STZ), Agrp (##p = 0.0090, KO + Ad-PDK2-GFP + STZ), and Pomc (#p = 0.0270, KO + Ad-PDK2-GFP + STZ) mRNA in the hypothalamic tissues isolated from Ad-PDK2-GFP or Ad-GFP and STZ-injected mice just after completion of behavioral assessments was evaluated by real-time RT-PCR (f). Results for mRNA expression are displayed as the fold increase of mRNA expression normalized to Gapdh. *p < 0.05, **p < 0.01, or ***p < 0.001 versus the vehicle-treated control animals (b, c, f) or STZ/Ad-GFP + STZ-treated animals (d, e); #p < 0.05, ##p < 0.01 between the indicated groups. One-way ANOVA (b, c, f) and two-way ANOVA with Tukey’s post hoc test (d, e), n = 3 (b), n = 4 (c, f), and n = 6 (d, e); mean ± SEM. Value of “n” indicates the number of animals. Source data are provided as a Source data file. d day(s); STZ streptozotocin; pfu plaque-forming unit; ns not significant; ND not detected.