Guixin Wu,Min Wen,Lin Sun,Huitao Li,Yubei Liu,Rui Li,Feihua Wu,Rong Yang,Yining Lin
Geniposide (GE) is a major component isolated from Gardenia jasminoides Ellis, which has been used to treat cholestasis liver diseases. Our previous study has shown that GE could notably increase mRNA and protein expressions of BSEP in cholestatic rats. BSEP plays a critical role in maintenance of the enterohepatic circulation of bile acids. BSEP could be regulated by the transactivation pathway of farnesoid X receptor (FXR) and nuclear factor erythroid 2-related factor (Nrf2). Here the mechanisms for BSEP regulation by GE were investigated. GE induced the mRNA levels of BSEP in HepG2 cells and cholestatic mice, and knockdown of FXR and Nrf2 reduced the mRNA expression of BSEP at varying degrees after treatment of GE. FXR acts as the major regulator of BSEP transcription. The involvement of FXR regulated BSEP expression by GE was further investigated. An enhancement was observed in FXR-dependent BSEP promoter activation using luciferase assay. ChIP assay further confirmed the interaction between FXR and BSEP after GE treatment. Using siRNA and ChIP assays, we demonstrated that peroxisome-proliferator-activated receptor γ co-activator-1α (PGC-1α) and co-activator-associated arginine methyltransferase 1 (CARM1) were predominantly recruited to the BSEP promoter upon FXR activation by GE. In conclusion, GE regulated the expression of BSEP through FXR and Nrf2 signaling pathway. The FXR transactivation pathway was enhanced by increasing recruitment of coactivators PGC-1α and CARM1 upon GE treatment, coupled with an increased binding of FXR to the BSEP promoter.
Inefficient priming, poor recruitment, and inadequate reinvigoration of T cells challenges the therapy of PD-L1-resistant tumors. Herein, a pH-responsive charge-reversal nanoplatform integrating coactivator-associated arginine methyltransferase 1 (CARM1) inhibitor (iCARM1) and poliovirus receptor siRNA (siPVR) is developed. Upon tumor penetration, iCARM1 released in tumor cells facilitates T cell priming by epigenetically activating cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling-mediated dendritic cell maturation. Meanwhile, in T cells, iCARM1 facilitates their recruitment by upregulating CXC-chemokine receptor 3 (CXCR3) expression. The released siPVR silences pvr to reinvigorate T cells. This epigenetic nanoagonist induces a robust immune response, dramatically suppresses tumor growth, metastasis, and relapse, and confers durable protection against secondary tumor challenge. Multiple PD-L1-resistant models demonstrate the broad applicability of this strategy. This study thus represents an innovative approach for facilitating multilevel T cell responses to combat PD-L1-resistant tumors.
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