MTOR and infection: Autophagy can also be induced for adaption and survival to environmental stimuli, such as nutrient starvation, hypoxia, endoplasmic reticulum (ER) stress, oxidative stress, infection, and pharmacological treatment, through the regulations of Wnt/β-catenin, AMP-activated protein kinase (AMPK), and mammalian target of rapamycin (mTOR) pathways [16,47].