The role of CYP1A1/2 in cholesterol ester accumulation provides a new perspective for the treatment of hypercholesterolemia.

Cholesterol is an important precursor of many endogenous molecules. Disruption of cholesterol homeostasis can cause many pathological changes, leading to liver and cardiovascular diseases. CYP1A is widely involved in cholesterol metabolic network, but its exact function has not been fully elucidated. Here, we aim to explore how CYP1A regulates cholesterol homeostasis. Our data showed that CYP1A1/2 knockout (KO) rats presented cholesterol deposition in blood and liver. The serum levels of low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and total cholesterol were significantly increased in KO rats. Further studies found that the lipogenesis pathway (LXRα-SREBP1-SCD1) of KO rats was activated, and the key protein of cholesterol ester hydrolysis (CES1) was inhibited. Importantly, lansoprazole can significantly alleviate rat hepatic lipid deposition in hypercholesterolemia models by inducing CYP1A. Our findings reveal the role of CYP1A as a potential regulator of cholesterol homeostasis and provide a new perspective for the treatment of hypercholesterolemia.

Design and Construction of Carboxylesterase 2c Gene Knockout Rats by CRISPR/Cas9.

BACKGROUND: Carboxylesterase 2 (CES2) is mainly distributed in the human liver and gut, and plays an active role in the metabolic activation of many prodrugs and lipid metabolism. Although CES2 is of great significance, there are still few animal models related to CES2. OBJECTIVES: This research aims to construct Ces2c gene knockout (KO) rats and further study the function of CES2. METHODS: CRISPR/Cas9 gene editing technology was used to target and cleave the rat Ces2c gene. Compensatory effects of major CES subtypes both in the liver and small intestine of KO rats were detected at mRNA levels. Meanwhile, diltiazem and aspirin were used as substrates to test the metabolic capacity of Ces2c in KO rats. RESULTS: This Ces2c KO rat model showed normal growth and breeding without off-target effects. The metabolic function of Ces2c KO rats was verified by the metabolic study of CES2 substrates in vitro. The results showed that the metabolic capacity of diltiazem in KO rats was weakened, while the metabolic ability of aspirin did not change significantly. In addition, the serum physiological indexes showed that the Ces2c deletion did not affect the liver function of rats.. CONCLUSION: The Ces2c KO rat model was successfully constructed by CRISPR/Cas9 system. This rat model can not only be used as an important tool to study the drug metabolism mediated by CES2, but also as an important animal model to study the physiological function of CES2.

DLK1-directed chimeric antigen receptor T-cell therapy for hepatocellular carcinoma.

BACKGROUND: Delta-like homologue 1 (DLK1), a transmembrane protein, is highly expressed in hepatocellular carcinoma (HCC). We explored whether DLK1-directed chimeric antigen receptor (CAR) T cells can specifically eliminate DLK1-positive HCC cells and serve as a therapeutic strategy for HCC immunotherapy. METHODS: We first characterized a homemade anti-human DLK1 monoclonal antibody, sequenced the single-chain Fragment variable (scFv) and integrated it into the second-generation CAR lentiviral vector, and then developed the DLK1-directed CAR-T cells. The cytotoxic activities of DLK1-directed CAR-T cells against different HCC cells were evaluated in vitro and in vivo. RESULTS: The genetically modified human T cells with the DLK1-directed CARs produced cytotoxic activity against DLK1-positive HCC cells. Additionally, the DLK1-directed CARs enhanced T cell proliferation and activation in a DLK1-dependent manner. Interestingly, the DLK1-targeted CAR-T cells significantly inhibited both subcutaneous and peritoneal xenograft tumours derived from human liver cancer cell lines HepG2 or Huh-7. CONCLUSION: DLK1-directed CAR-T cells specifically suppresses DLK1-positive HCC cells in vitro and in vivo. This study provides a novel transmembrane antigen DLK1 as a potential therapeutic target appropriate for CAR-T cell therapy, which may be further developed as a clinical therapeutic strategy for HCC immunotherapy.

Construction and Characterization of CRISPR/Cas9 Knockout Rat Model of Carboxylesterase 2a Gene.

Carboxylesterase (CES) 2, an important metabolic enzyme, plays a critical role in drug biotransformation and lipid metabolism. Although CES2 is very important, few animal models have been generated to study its properties and functions. Rat Ces2 is similar to human CES2A-CES3A-CES4A gene cluster, with highly similar gene structure, function, and substrate. In this report, CRISPR-associated protein-9 (CRISPR/Cas9) technology was first used to knock out rat Ces2a, which is a main subtype of Ces2 mostly distributed in the liver and intestine. This model showed the absence of CES2A protein expression in the liver. Further pharmacokinetic studies of diltiazem, a typical substrate of CES2A, confirmed the loss of function of CES2A both in vivo and in vitro. At the same time, the expression of CES2C and CES2J protein in the liver decreased significantly. The body and liver weight of Ces2a knockout rats also increased, but the food intake did not change. Moreover, the deficiency of Ces2a led to obesity, insulin resistance, and liver fat accumulation, which are consistent with the symptoms of nonalcoholic fatty liver disease (NAFLD). Therefore, this rat model is not only a powerful tool to study drug metabolism mediated by CES2 but also a good disease model to study NAFLD. SIGNIFICANCE STATEMENT: Human carboxylesterase (CES) 2 plays a key role in the first-pass hydrolysis metabolism of most oral prodrugs as well as lipid metabolism. In this study, CRISPR/Cas9 technology was used to knock out Ces2a gene in rats for the first time. This model can be used not only in the study of drug metabolism and pharmacokinetics but also as a disease model of nonalcoholic fatty liver disease (NAFLD) and other metabolic disorders.

Generation and Characterization of Cytochrome P450 2J3/10 CRISPR/Cas9 Knockout Rat Model.

Cytochrome P450 2J2 (CYP2J2) enzyme attracts more attention because it not only metabolizes clinical drugs but also mediates the biotransformation of important endogenous substances and the regulation of physiologic function. Although CYP2J2 is very important, few animal models are available to study its function in vivo In particular, a CYP2J gene knockout (KO) rat model for drug metabolism and pharmacokinetics is not available. In this report, the CRISPR/Cas9 technology was used to delete rat CYP2J3/10, the orthologous genes of CYP2J2 in humans. The CYP2J3/10 KO rats were viable and fertile and showed no off-target effect. Compared with wild-type (WT) rats, the mRNA and protein expression of CYP2J3/10 in liver, small intestine, and heart of KO rats were completely absent. At the same time, CYP2J4 mRNA expression and protein expression were significantly decreased in these tissues. Further in vitro and in vivo metabolic studies of astemizole, a typical substrate of CYP2J, indicated that CYP2J was functionally inactive in KO rats. The heart function indexes of WT and KO rats were also measured and compared. The myocardial enzymes, including creatine kinase-muscle brain type (CK-MB), creatine kinase (CK), and CK-MB/CK ratio, of KO rats increased by nearly 140%, 80%, and 60%, respectively. In conclusion, this study successfully developed a new CYP2J3/10 KO rat model, which is a useful tool to study the function of CYP2J in drug metabolism and cardiovascular disease. SIGNIFICANCE STATEMENT: Human CYP2J2 is involved not only in clinical drug metabolism but also in the biotransformation of important endogenous substances. Therefore, it is very important to construct new animal models to study its function in vivo. This study successfully developed a new CYP2J knockout rat model by using CRISPR/Cas9 technology. This rat model provides a useful tool to study the role of CYP2J in drug metabolism and diseases.

Characterization of organic anion transporting polypeptide 1b2 knockout rats generated by CRISPR/Cas9: a novel model for drug transport and hyperbilirubinemia disease.

Organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1/3) as important uptake transporters play a fundamental role in the transportation of exogenous drugs and endogenous substances into cells. Rat OATP1B2, encoded by the Slco1b2 gene, is homologous to human OATP1B1/3. Although OATP1B1/3 is very important, few animal models can be used to study its properties. In this report, we successfully constructed the Slco1b2 knockout (KO) rat model via using the CRISPR/Cas9 technology for the first time. The novel rat model showed the absence of OATP1B2 protein expression, with no off-target effects as well as compensatory regulation of other transporters. Further pharmacokinetic study of pitavastatin, a typical substrate of OATP1B2, confirmed the OATP1B2 function was absent. Since bilirubin and bile acids are the substrates of OATP1B2, the contents of total bilirubin, direct bilirubin, indirect bilirubin, and total bile acids in serum are significantly higher in Slco1b2 KO rats than the data of wild-type rats. These results are consistent with the symptoms caused by the absence of OATP1B1/3 in Rotor syndrome. Therefore, this rat model is not only a powerful tool for the study of OATP1B2-mediated drug transportation, but also a good disease model to study hyperbilirubinemia-related diseases.

New insights of CYP1A in endogenous metabolism: a focus on single nucleotide polymorphisms and diseases.

Cytochrome P450 1A (CYP1A), one of the major CYP subfamily in humans, not only metabolizes xenobiotics including clinical drugs and pollutants in the environment, but also mediates the biotransformation of important endogenous substances. In particular, some single nucleotide polymorphisms (SNPs) for CYP1A genes may affect the metabolic ability of endogenous substances, leading to some physiological or pathological changes in humans. This review first summarizes the metabolism of endogenous substances by CYP1A, and then introduces the research progress of CYP1A SNPs, especially the research related to human diseases. Finally, the relationship between SNPs and diseases is discussed. In addition, potential animal models for CYP1A gene editing are summarized. In conclusion, CYP1A plays an important role in maintaining the health in the body.

Organic anion transport polypeptide 1b2 selectively affects the pharmacokinetic interaction between paclitaxel and sorafenib in rats.

Paclitaxel, a broad-spectrum antitumor drug, is widely used as a cytotoxic drug, while sorafenib as a multi-kinase inhibitor is a classic targeted drug. A number of clinical trials have combined paclitaxel and sorafenib for cancer treatment, with the expectation of better therapeutic effects. However, the toxicity and side effects in the treatment are significantly increased. In this report, the organic anion transport polypeptide 1b2 (Oatp1b2) overexpression cell model and the Oatp1b2 knockout (KO) rat model were used to investigate the drug-drug interactions (DDI) between paclitaxel and sorafenib. In Oatp1b2-overexpressed cells, sorafenib inhibited the uptake of paclitaxel in a concentration-dependent manner. In wild-type (WT) rats, sorafenib increased the systemic exposure and slowed the elimination of paclitaxel, resulting in DDI. In Oatp1b2 KO rats, however, the DDI disappeared. Interestingly, paclitaxel did not alter the pharmacokinetic profiles of sorafenib. Further studies found that sorafenib was not the substrate of Oatp1b2 in rats. In general, the combination of paclitaxel and sorafenib caused Oatp1b2-mediated DDI in vitro and in vivo, because sorafenib inhibited Oatp1b2 activity and affected the pharmacokinetic properties of paclitaxel. This study may provide useful information for understanding the role of OATP1B in paclitaxel-sorafenib interaction.

Development and Characterization of MDR1 (Mdr1a/b) CRISPR/Cas9 Knockout Rat Model.

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) technology is widely used as a tool for gene editing in rat genome site-specific engineering. Multidrug resistance 1 [MDR1 (also known as P-glycoprotein)] is a key efflux transporter that plays an important role not only in the transport of endogenous and exogenous substances, but also in tumor MDR. In this report, a novel MDR1 (Mdr1a/b) double-knockout (KO) rat model was generated by the CRISPR/Cas9 system without any off-target effect detected. Western blot results showed that MDR1 was completely absent in the liver, small intestine, brain, and kidney of KO rats. Further pharmacokinetic studies of digoxin, a typical substrate of MDR1, confirmed the deficiency of MDR1 in vivo. To determine the possible compensatory mechanism of Mdr1a/b (-/-) rats, the mRNA levels of the CYP3A subfamily and transporter-related genes were compared in the brain, liver, kidney, and small intestine of KO and wild-type rats. In general, a new Mdr1a/b (-/-) rat model has been successfully generated and characterized. This rat model is a useful tool for studying the function of MDR1 in drug absorption, tumor MDR, and drug target validation.