KLF4 and infection: Meanwhile, RT-qPCR results for determination of KLF4 expression patterns in sh-KLF4 or sh-NC-treated neurons on the 3rd day after infection demonstrated that KLF4 expression levels were significantly reduced in the presence of sh-KLF4 (p < 0.05), indicating successful construction of neurons with silenced KLF4 (Figures 4A,B).