(A and B) Western blot and densitometry quantification (normalized to loading control and presented as FC over iAT2^WT of serially cultured human iAT2 cells (135–182 days) demonstrate increased LDHA/B ratio and decreased p-AMPK/AMPK ratio in iAT2^I73T (SFTPC^{I73T/tdTomato}) cells compared with syngeneic corrected iAT2^WT cells (SFTPC^WT/tdTomato) (mean±SEM; n = 3 biological replicates). (C) Measurement of extracellular lactate by YSI biochemistry analyzer shows increased extracellular lactate in iAT2^I73T compared with iAT2^WT cells. This increase is significantly reduced by treatment with AICAR (1 mM, 24 hours) (mean±SEM; n = 3 biological replicates for AICAR-treated and n = 5 biological replicates for vehicle-treated, each with 2 experimental replicates of independent wells). (D) Unsupervised hierarchical clustering (Euclidean) heatmap of all DEGs (FDR < 0.05) in iAT2^WT and iAT2^I73T cells treated with AICAR treatment (1 mM, 24 hours) or vehicle (row-normalized z-score). Gene ontology (GO) analysis of each subgroup using Database for Annotation, Visualization, and Integrated Discovery (DAVID) identifies increased expression of genes associated with fatty acid and lipid synthesis and reduced expression of transcripts linked to cell cycle regulation and glycolysis after AICAR treatment. A subset of sample genes from each GO term is highlighted. (E and F) Western blot of AMPK pathway targets in iAT2^I73T cell lysates verifies AMPK signaling activation and increased PGC1α phosphorylation following AICAR treatment (1 mM, 24 hours). Bar graphs depict densitometric quantification (mean±SEM; n = 3 biological replicates). (G) Respirometry quantification depicted as OCR/ECAR ratio in iAT2^I73T and iAT2^WT cells following AICAR (1 mM, 24 hours) treatment (mean±SEM; n = 3 biological replicates). *P < 0.05, **P < 0.005, ***P < 0.0005, by ordinary 1-way ANOVA (C and G) and 1-tailed unpaired t test (B and F).