AAV-CRISPR Gene Editing Is Negated by Pre-existing Immunity to Cas9

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Characterization of CYP2C Induction in Cryopreserved Human Hepatocytes and Its Application in the Prediction of the Clinical Consequences of the Induction

CYP2C enzymes play key roles in drug metabolism, and clinical drug-drug interactions caused by CYP2C induction have been reported. The aim of this study was to establish a method to predict the potency of CYP2C inductions considering the mechanism. We first investigated the relations of CYP2C induction with CYP3A4 or CYP2B6 induction in human hepatocytes after 48-h exposure with 19 inducers. The fold-induction values of CYP2C8 and CYP2C9 were well correlated with those of CYP3A4, whereas the inducers were separated into 2 groups showing different correlations with CYP2B6 induction for CYP2C8 and CYP2C9 induction. In the regression models established, the fold-induction values of CYP2C8 and CYP2C9 were well expressed as the functions of those of CYP3A4 and CYP2B6, while no such obvious correlation was observed for CYP2C19 induction. These results suggest that CYP2Cs are not simply coinduced with CYP3A4 and that CYP2C8 and CYP2C9 inductions are regulated by both pregnane X receptor and constitutive androstane receptor with different contributions. Finally, simple correlations were proposed using the experimental E_max values obtained and plasma concentrations of CYP2C9 substrates from the literature, and positive correlations were observed. These data provide methods to estimate the clinical impact of CYP2C9 induction from in vitro data.     

In vitro metabolism of alectinib,a novel potent ALK inhibitor,in human: contribution of CYP3A enzymes

1.?The in vitro metabolism of alectinib, a potent and highly selective oral anaplastic lymphoma kinase inhibitor, was investigated.

2.?The main metabolite (M4) in primary human hepatocytes was identified, which is produced by deethylation at the morpholine ring. Three minor metabolites (M6, M1a, and M1b) were also identified, and a minor peak of hydroxylated alectinib (M5) was detected as a possible precursor of M4, M1a, and M1b.

3.?M4, an important active major metabolite, was produced and further metabolized to M6 by CYP3A, indicating that CYP3A enzymes were the principal contributors to this route. M5 is possibly produced by CYP3A and other isoforms as the primary step in metabolism, followed by oxidation to M4 mainly by CYP3A. Alternatively, M5 could be oxidized to M1a and M1b via an NAD-dependent process. None of the non-CYP3A-mediated metabolism appeared to be major.

4.?In conclusion, this study suggests that involvement of multiple enzymes in the metabolism of alectinib reduces its potential for drug–drug interactions.     

衰老表型肝细胞外泌体对脂多糖致炎软骨细胞的影响及白芍的干预效应

目的  研究衰老表型的肝细胞外泌体对脂多糖(LPS)刺激软骨细胞的影响及白芍的干预效应。方法  提取小鼠肝原代细胞,CCK-8法筛选白芍水煎液干预肝细胞的最佳浓度。随后,肝细胞随机分为空白组、衰老组和白芍组,0.3 mmol·L-1过氧化氢诱导肝细胞衰老,检测肝细胞p16、p21、p53的基因和蛋白表达,观察肝细胞衰老及白芍的干预效应。分别提取各组肝细胞上清中的外泌体,通过电镜、粒径分析、四旋蛋白CD9、CD63、CD81鉴定外泌体。培养小鼠软骨细胞,LPS刺激以模拟KOA炎症环境,检测细胞上清液中TNF-α和IL-1β含量以验证造模成功。PHK67染色标记肝细胞外泌体并观察软骨细胞的摄入情况。将收集的各组肝细胞外泌体用于干预LPS致炎软骨细胞,检测软骨细胞基质降解合成标记物MMP3、MMP13、SOX9、ADAMTS5的基因和蛋白表达水平。结果  经CCK-8法筛选,100 μg·mL-1为白芍水煎液干预肝细胞的最佳浓度。过氧化氢干预后,衰老组中细胞衰老标记物p16、p21、p53的基因和蛋白表达均高于正常组(P < 0.05),而在白芍组则较衰老组降低(P < 0.05)。各组肝细胞所收集外泌体均呈现双层膜结构,形态大小无差异,粒径富集均满足40~120 nm区间,代表性粒径富集于116.8 nm,丰度98%,外泌体标记物四旋蛋白CD9、CD63、CD81均为阳性表达。软骨细胞上清液中,促炎因子TNF-α、IL-1β的含量均在LPS刺激后较刺激前升高(P < 0.01),PHK67染色试剂确认软骨细胞对各组肝细胞外泌体的摄入。衰老组肝细胞外泌体的干预下,软骨细胞基质降解合成标记物MMP3、MMP13、SOX9、ADAMTS5的基因和蛋白表达水平均较空白组肝细胞外泌体干预升高(P < 0.05),而白芍组肝细胞外泌体干预则较衰老组肝细胞外泌体干预降低(P < 0.05)。结论  衰老表型肝细胞外泌体可加剧LPS致炎软骨细胞的退变进程,白芍水煎剂对此环节存在良性干预。      

The many ways to mend your liver: A critical appraisal

In the latter half of the 20th century, our understanding of mammalian liver regeneration was shaped by the manner of compensatory hyperplasia occurring after a partial rat liver resection. This response involves almost all hepatocytes and thus is unlikely to be the outcome of the multiple cycling of a small stem cell population. It was most intense in the outer third of lobule, the location closest to the afferent arterial blood supply. With the advent of heritable genetic labelling techniques, usually applied to mice, hitherto unrecognized hepatocytes with clonogenic potential have been discovered, contributing to homoeostatic renewal and/or regenerative responses after tissue loss. This review combines observations from cell lineage tracing studies with other data to summarize the Four proposed anatomical locations for hepatocyte stem cells: the periportal zone, the pericentral zone, a randomized distribution and finally within the intrahepatic biliary tree. As in other endodermal‐derived tissues, it appears that there are both homoeostatic stem cells and regenerative stem cells, while some normally homoeostatic stem cells can become more active to boost regeneration.     

肝细胞移植的研究进展

肝细胞移植已初步完成了从基础研究向临床应用的转化,目前认为,肝细胞移植在治疗终末期肝病和代谢性肝病中发挥重要作用。本文综述了肝细胞移植过程中所遇到的关键问题及其研究进展。尽管面临肝细胞来源缺乏及一些关键技术有待改进等问题,但越来越多的临床试验数据表明肝细胞移植具有十分广阔的应用前景。     

Measurement of Human Cytochrome P450 Enzyme Induction Based on Mesalazine and Mosapride Citrate Treatments Using a Luminescent Assay

Drug metabolism mostly occurs in the liver. Cytochrome P450 (CYP) is a drug-metabolizing enzyme that is responsible for many important drug metabolism reactions. Recently, the US FDA and EU EMA have suggested that CYP enzyme induction can be measured by both enzymatic activity and mRNA expression. However, these experiments are time-consuming and their inter-assay variability can lead to misinterpretations of the results. To resolve these problems and establish a more powerful method to measure CYP induction, we determined CYP induction by using luminescent assay. Luminescent CYP assays link CYP enzyme activity to firefly luciferase luminescence technology. In this study, we measured the induction of CYP isozymes (1A2, 2B6, 2C9, and 3A4) in cryopreserved human hepatocytes (HMC424, 478, and 493) using a luminometer. We then examined the potential induction abilities (unknown so far) of mesalazine, a drug for colitis, and mosapride citrate, which is used as an antispasmodic drug. The results showed that mesalazine promotes CYP2B6 and 3A4 activities, while mosapride citrate promotes CYP1A2, 2B6, and 3A4 activities. Luminescent CYP assays offer rapid and safe advantages over LC-MS/MS and qRT-PCR methods. Furthermore, luminescent CYP assays decrease the interference between the optical properties of the test compound and the CYP substrates. Therefore, luminescent CYP assays are less labor intensive, rapid, and can be used as robust tools for high-throughput CYP screening during early drug discovery.     

Human hepatocyte assessment of imatinib drug–drug interactions – complexities in clinical translation

Aim

Inducers and inhibitors of CYP3A, such as ritonavir and efavirenz, may be used as part of the highly active antiretroviral therapy (HAART) to treat HIV patients. HIV patients with chronic myeloid leukemia or gastrointestinal stromal tumour may need imatinib, a CYP3A4 substrate with known exposure response–relationships. Administration of imatinib to patients on ritonavir or efavirenz may result in altered imatinib exposure leading to increased toxicity or failure of therapy, respectively. We used primary human hepatocyte cultures to evaluate the magnitude of interaction between imatinib and ritonavir/efavirenz.

Methods

Hepatocytes were pre-treated with vehicle, ritonavir, ketoconazole, efavirenz or rifampicin, and the metabolism of imatinib was characterized over time. Concentrations of imatinib and metabolite were quantitated in combined lysate and medium, using LC-MS.

Results

The predicted changes in imatinib CL_oral (95% CI) with ketoconazole, ritonavir, rifampicin and efavirenz were 4.0-fold (0, 9.2) lower, 2.8-fold (0.04, 5.5) lower, 2.9-fold (2.2, 3.5) higher and 2.0-fold (0.42, 3.5) higher, respectively. These predictions were in good agreement with clinical single dose drug–drug interaction studies, but not with reports of imatinib interactions at steady-state. Alterations in metabolism were similar after acute or chronic imatinib exposure.

Conclusions

In vitro human hepatocytes predicted increased clearance of imatinib with inducers and decreased clearance with inhibitors of CYP enzymes. The impact of HAART on imatinib may depend on whether it is being initiated or has already been dosed chronically in patients. Therapeutic drug monitoring may have a role in optimizing imatinib therapy in this patient population.     

Detection of mono- and di-hexoses as metabolites of 4-bromoaniline using HPLC-TOF-MS/MS

1. The metabolic fate of 4-bromoaniline (4-BrA) was investigated in rat following intraperitoneal administration at 50?mg kg ? 1 using HPLC-TOF-MS/MS. 2. The sensitivity provided by the use of TOF-MS/MS, aided by the distinctive isotope pattern resulting from the presence of the bromine substituent in the molecule, enabled the detection of many previously uncharacterized metabolites in the samples. 3. Several groups of minor metabolites were detected in the urine that corresponded to a number of isomeric hexose and di-hexose-containing conjugates (possibly glucosides and diglucosides) of 4-BrA. 4. As well as hexose and di-hexose conjugates of 4-BrA, several further groups of metabolites that also contained either a sulphamate or sulphate group in addition to the sugar moieties were also detected.