Fig. 7.

Schematic diagram of mTORC1/NF-κB/DPP4 signaling pathway activation in HPH. Hypoxia activates the Akt/mTORC1 signaling pathway in PASMCs; mTORC1 phosphorylates IKKα/β, and IKKα/β then phosphorylates IκB. This leads to the degradation of IκB and thus the release and activation of NF-κB. Activated NF-κB moves to the nucleus and induces the expression of its target gene DPP4. Inhibition of DPP4 by sitagliptin can attenuate HPH