Role of Nrf2 in the pathogenesis of respiratory diseases

Penehyclidine hydrochloride inhibits renal ischemia/reperfusion-induced acute lung injury by activating the Nrf2 pathway

The nuclear factor (NF)-κB and NOD-like receptor protein 3 (NLRP3) pathways promote inflammatory signaling that injures the kidneys, whereas the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway promotes anti-inflammatory signaling that inhibits oxidative damage. Penehyclidine hydrochloride (PHC) inhibits NF-κB and activates Nrf2 signaling. We investigated whether PHC induces communication between the Nrf2 and NF-κB/NLRP3 pathways, thereby protecting against renal ischemia/reperfusion (rI/R)-induced lung inflammation. Rat alveolar macrophages (NR8383 cells) were stimulated for 24 h with PHC with or without brusatol (a Nrf2 antagonist), after which they were treated for 4 h with tert-butyl hydroperoxide (10 mM). PHC Nrf2-dependently alleviated tert-butyl hydroperoxide-induced reactive oxygen species production in alveolar macrophages. Additionally, wild-type and Nrf2^-/- rats were each divided into four groups: (1) sham, (2) PHC (1 mg/kg), (3) rI/R and (4) rI/R + PHC (1 mg/kg). PHC markedly induced the Nrf2 and adenosine monophosphate-activated protein kinase pathways and suppressed rI/R-induced NF-κB and NLRP3 activation in the lungs. Nrf2 deficiency diminished the ability of PHC to ameliorate rI/R-induced histopathological alterations and reactive oxygen species release in the lungs; however, PHC inhibited NLRP3 signaling Nrf2-dependently, while it inhibited NF-κB signaling Nrf2-independently. Our findings demonstrate the beneficial effects of PHC on rI/R-induced lung inflammation.

Whole-exome mutational landscape of metastasis in patient-derived hepatocellular carcinoma cells

In order to explore the genomic basis for liver cancer metastasis, whole-exome sequencing (WES) was performed on patient-derived hepatocellular carcinoma (HCC) cell lines with differential metastatic potentials and analyzed their clonal evolution relationships. An evolutionary tree based on genomic single nucleotide polymorphism (SNP) was constructed in MegaX software. The WES data showed that the average percentage of heterogeneous mutations in each HCC cell lines was 16.55% (range, 15.38%–18.17%). C: G > T: A and T: A > C: G somatic transitions were the two most frequent substitutions. In these metastatic HCC cell lines, non-silent gene mutations were found in 21.88% of known driver genes and 10 classical signaling pathways. The protein interaction network was constructed by STRING, and hub genes were found in the shared trunk mutation genes and the heterogeneous branch mutations respectively. In cBioPortal database, some of the selected hub genes were found to be associated with poor overall survival (OS) of HCC patients. Among the mutated HCC driver genes, a novel KEAP1 mutation with a homozygous frameshift truncation at the c-terminal Nrf2 binding region was detected and verified in MHCC97-H and HCC97LM3 cells. In conclusion, WES data demonstrate that HCC cell lines from tumor biopsy specimens of the same patient have obtained different metastatic potentials through repeated selection in rodents in vivo, and they do indeed have a genetic relationship at the genomic level.