Cytochrome P450 1 (CYP1) is an important enzyme family involved in the metabolism of pollutants, and used as a biomarker to monitor environmental pollution. In this study, a fluorescence-labeled cyp1a zebrafish line, named as KI ( cyp1a +/+ -T2A-mCherry) (KICM), was originally constructed to monitor dioxin-like compounds in the environment. However, the cyp1a gene expression in the KICM line was inhibited by the fluorescence labeling, thus leading to a significantly increased sensitivity of KICM zebrafish line to PAHs. Then, a cyp1a knockout zebrafish line, named KOC, were constructed for comparative analysis with the cyp1a low-expression line. Interestingly, knockout of the cyp1a gene did not increase the sensitivity of zebrafish to PAHs as significantly as the cyp1a low-expression line. So, the expression levels of related genes in the aryl hydrocarbon receptor pathway were analyzed and the results showed that the expression level of cyp1b in KOC group was significantly higher than that of wild type and KICM under the same PAH exposure. This indicated that the effect of losing cyp1a was compensated by inducing expression of cyp1b . In conclusion, two new zebrafish models including cyp1a low-expression line and cyp1a knockout line were constructed in this study, which may provide a convenient model for subsequent studies on the toxicity mechanism of PAHs and the role of cyp1a in detoxification.
Liver fibrosis (LF) afflicts millions of patients worldwide, yet a universally accepted standard therapy remains elusive. Notably, an elevation of profibrotic monocytes is observed in peripheral blood of LF patients. Inspired by the spleen’s reported “accomplice” role in LF development and its monocyte reservoir function, the mechanism of spleen-liver co-morbidity is further explored, unveiling an innovative therapy strategy for LF. In detail, exosomes are prepared from macrophages with low expression of lymphocyte antigen 6 complex locus C (ly6c low Exo), showcasing a distinctive ability to accumulate simultaneously in both spleen and liver. The ly6c low Exo treatment reduces profibrotic monocyte proportion in spleen, decreases the circulating profibrotic monocytes, and reshapes hepatic immune microenvironment including macrophages, T cells, and natural killer cells. Such synergistic modulation culminates in the reduction of extracellular matrix, achieving satisfying therapeutic outcomes in LF model. Furthermore, the exosome therapeutic is iterated via loading pirfenidone into ly6c low Exo. A cooperation of two distinct mechanisms is thus achieved by combining the ly6c low Exo immunoregulation with pirfenidone-mediated transforming growth factor-β pathway inhibition, resulting in an enhanced antifibrotic effect in severe LF model. The ly6c low Exo platform described, with its remarkable capacity for dual-accumulation, multifunctional immunoregulatory capabilities, and drug-loading property, presents extensive clinical application prospects for LF treatment.
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