PDK1 and infection: Among the dysregulated genes, TIGR4 infection significantly upregulated IDH3A (isocitrate dehydrogenase 3) and PDK1 (pyruvate dehydrogenase kinase 1) RNA expression in Calu-3 cells (Fig. 4H), while downregulating PC (pyruvate carboxylase), PDK2 (pyruvate dehydrogenase kinase 2), and PDPR (pyruvate dehydrogenase phosphatase regulatory subunit).