In Ttp mice models of KCs and primary hepatocytes, metformin activates the mRNA-binding protein tristetraproline (TTP) through the AMPK-Sirt1 pathway in both hepatocytes and KCs, this activation curtails TNF-α production in KCs, downregulates Rheb expression, suppresses mTORC1 expression, and enhances TFEB nuclear translocation (165). Here, RHEB is linked to dry eye syndrome.