UGT1A1 dysfunction increases liver burden and aggravates hepatocyte damage caused by long-term bilirubin metabolism disorder

Icaritin exhibits potential drug-drug interactions through the inhibition of human UDP-glucuronosyltransferase in vitro

Icaritin is a prenylflavonoid derivative of the genus Epimedium (Berberidaceae) and has a variety of pharmacological actions. Icaritin is approved by the National Medical Products Administration as an anticancer drug that exhibits efficacy and safety advantages in patients with hepatocellular carcinoma cells. This study aimed to evaluate the inhibitory effects of icaritin on UDP-glucuronosyltransferase (UGT) isoforms. 4-Methylumbelliferone (4-MU) was employed as a probe drug for all the tested UGT isoforms using in vitro human liver microsomes (HLM). The inhibition potentials of UGT1A1 and 1A9 in HLM were further tested by employing 17β-estradiol (E2) and propofol (PRO) as probe substrates, respectively. The results showed that icaritin inhibits UGT1A1, 1A3, 1A4, 1A7, 1A8, 1A10, 2B7, and 2B15. Furthermore, icaritin exhibited a mixed inhibition of UGT1A1, 1A3, and 1A9, and the inhibition kinetic parameters (Ki) were calculated to be 3.538, 2.117, and 0.306 (μM), respectively. The inhibition of human liver microsomal UGT1A1 and 1A9 both followed mixed mechanism, with Ki values of 2.694 and 1.431 (μM). This study provides supporting information for understanding the drug-drug interaction (DDI) potential of the flavonoid icaritin and other UGT-metabolized drugs in clinical settings. In addition, the findings provide safety evidence for DDI when liver cancer patients receive a combination therapy including icaritin.

Combination of UGT1A1 polymorphism and baseline plasma bilirubin levels in predicting the risk of antipsychotic-induced dyslipidemia in schizophrenia patients

The prolonged usage of atypical antipsychotic drugs (AAPD) among individuals with schizophrenia often leads to metabolic side effects such as dyslipidemia. These effects not only limit one's selection of AAPD but also significantly reduce compliance and quality of life of patients. Recent studies suggest that bilirubin plays a crucial role in maintaining lipid homeostasis and may be a potential pre-treatment biomarker for individuals with dyslipidemia. The present study included 644 schizophrenia patients from two centers. Demographic and clinical characteristics were collected at baseline and 4 weeks after admission to investigate the correlation between metabolites, episodes, usage of AAPDs, and occurrence of dyslipidemia. Besides, we explored the combined predictive value of genotypes and baseline bilirubin for dyslipidemia by employing multiple PCR targeted capture techniques to sequence two pathways: bilirubin metabolism-related genes and lipid metabolism-related genes. Our results indicated that there existed a negative correlation between the changes in bilirubin levels and triglyceride (TG) levels in patients with schizophrenia. Among three types of bilirubin, direct bilirubin in the baseline (DBIL-bl) proved to be the most effective in predicting dyslipidemia in the ROC analysis (AUC = 0.627, p < 0.001). Furthermore, the odds ratio from multinomial logistic regression analysis showed that UGT1A1*6 was a protective factor for dyslipidemia (ß = -12.868, p < 0.001). The combination of baseline DBIL and UGT1A1*6 significantly improved the performance in predicting dyslipidemia (AUC = 0.939, p < 0.001). Schizophrenia patients with UGT1A1*6 mutation and a certain level of baseline bilirubin may be more resistant to dyslipidemia and have more selections for AAPD than other patients.

Comparative transcriptomic and phenotypic analysis of induced pluripotent stem cell hepatocyte-like cells and primary human hepatocytes

Primary human hepatocytes (PHHs) are used extensively for in vitro liver cultures to study hepatic functions. However, limited availability and invasive retrieval prevent their widespread use. Induced pluripotent stem cells exhibit significant potential since they can be obtained non-invasively and differentiated into hepatic lineages, such as hepatocyte-like cells (iHLCs). However, there are concerns about their fetal phenotypic characteristics and their hepatic functions compared to PHHs in culture. Therefore, we performed an RNA-sequencing (RNA-seq) analysis to understand pathways that are either up- or downregulated in each cell type. Analysis of the RNA-seq data showed an upregulation in the bile secretion pathway where genes such as AQP9 and UGT1A1 were higher expressed in PHHs compared to iHLCs by 455- and 15-fold, respectively. Upon immunostaining, bile canaliculi were shown to be present in PHHs. The TCA cycle in PHHs was upregulated compared to iHLCs. Cellular analysis showed a 2-2.5-fold increase in normalized urea production in PHHs compared to iHLCs. In addition, drug metabolism pathways, including cytochrome P450 (CYP450) and UDP-glucuronosyltransferase enzymes, were upregulated in PHHs compared to iHLCs. Of note, CYP2E1 gene expression was significantly higher (21,810-fold) in PHHs. Acetaminophen and ethanol were administered to PHH and iHLC cultures to investigate differences in biotransformation. CYP450 activity of baseline and toxicant-treated samples was significantly higher in PHHs compared to iHLCs. Our analysis revealed that iHLCs have substantial differences from PHHs in critical hepatic functions. These results have highlighted the differences in gene expression and hepatic functions between PHHs and iHLCs to motivate future investigation.

Dysregulated Glucuronidation of Bilirubin Exacerbates Liver Inflammation and Fibrosis in Schistosomiasis Japonica through the NF-κB Signaling Pathway

Hepatic fibrosis is an important pathological manifestation of chronic schistosome infection. Patients with advanced schistosomiasis show varying degrees of abnormalities in liver fibrosis indicators and bilirubin metabolism. However, the relationship between hepatic fibrosis in schistosomiasis and dysregulated bilirubin metabolism remains unclear. In this study, we observed a positive correlation between total bilirubin levels and the levels of ALT, AST, LN, and CIV in patients with advanced schistosomiasis. Additionally, we established mouse models at different time points following S. japonicum infection. As the infection time increased, liver fibrosis escalated, while liver UGT1A1 consistently exhibited a low expression, indicating impaired glucuronidation of bilirubin metabolism in mice. In vitro experiments suggested that SEA may be a key inhibitor of hepatic UGT1A1 expression after schistosome infection. Furthermore, a high concentration of bilirubin activated the NF-κB signaling pathway in L-O2 cells in vitro. These findings suggested that the dysregulated glucuronidation of bilirubin caused by S. japonicum infection may play a significant role in schistosomiasis liver fibrosis through the NF-κB signaling pathway.

Uridine diphosphate glucuronosyltransferase 1A1 prevents the progression of liver injury

BACKGROUND

Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) plays a crucial role in metabolizing and detoxifying endogenous and exogenous substances. However, its contribution to the progression of liver damage remains unclear.

AIM

To determine the role and mechanism of UGT1A1 in liver damage progression.

METHODS

We investigated the relationship between UGT1A1 expression and liver injury through clinical research. Additionally, the impact and mechanism of UGT1A1 on the progression of liver injury was analyzed through a mouse model study.

RESULTS

Patients with UGT1A1 gene mutations showed varying degrees of liver damage, while patients with acute-on-chronic liver failure (ACLF) exhibited relatively reduced levels of UGT1A1 protein in the liver as compared to patients with chronic hepatitis. This suggests that low UGT1A1 levels may be associated with the progression of liver damage. In mouse models of liver injury induced by carbon tetrachloride (CCl4) and concanavalin A (ConA), the hepatic levels of UGT1A1 protein were found to be increased. In mice with lipopolysaccharide or liver steatosis-mediated liver-injury progression, the hepatic protein levels of UGT1A1 were decreased, which is consistent with the observations in patients with ACLF. UGT1A1 knockout exacerbated CCl4- and ConA-induced liver injury, hepatocyte apoptosis and necroptosis in mice, intensified hepatocyte endoplasmic reticulum (ER) stress and oxidative stress, and disrupted lipid metabolism.

CONCLUSION

UGT1A1 is upregulated as a compensatory response during liver injury, and interference with this upregulation process may worsen liver injury. UGT1A1 reduces ER stress, oxidative stress, and lipid metabolism disorder, thereby mitigating hepatocyte apoptosis and necroptosis.

Genetic Polymorphisms of UDP-Glucuronosyltransferases and Susceptibility to Antituberculosis Drug-Induced Liver Injury: A Systematic Review and Meta-Analysis

Methods

The PRISMA statement was strictly followed, and the protocol was registered in PROSPERO (CRD42022339317). The PICOS framework was used: patients received antituberculosis treatment, UGTs polymorphisms (mutants), UGTs polymorphisms (wild), AT-DILI, and case-control studies. Eligible studies were searched through nine databases up to April 27, 2022. The study's qualities were assessed by the revised Little's recommendations. Meta-analysis was conducted with a random-effects model using odds ratios (ORs) with 95% confidence intervals (95% CIs) as the effect size.

Results

Twelve case-control studies with 2128 cases and 4338 controls were included, and 32 single nucleotide polymorphisms (SNPs) in the seven UGT genes have been reported in Chinese and Korean. All studies were judged as high quality. The pooled results indicated that UGT1A1 rs3755319 (AC vs. AA, OR = 1.454, 95% CI: 1.100-1.921, P = 0.009), UGT2B7 rs7662029 (G vs. A, OR = 1.547, 95% CI: 1.249-1.917, P < 0.0001; GG + AG vs. AA, OR = 2.371, 95% CI: 1.779-3.160, P < 0.0001; AG vs. AA, OR = 2.686, 95% CI: 1.988-3.627, P < 0.0001), and UGT2B7 rs7439366 (C vs. T, OR = 0.585, 95% CI: 0.477-0.717, P < 0.0001; CC + TC vs. TT, OR = 0.347, 95% CI: 0.238-0.506, P < 0.0001; CC vs. TC + TT, OR = 0.675, 95% CI: 0.507-0.898, P = 0.007) might be associated with the risk of AT-DILI.

Conclusions

The polymorphisms of UGT1A1 rs3755319, UGT2B7 rs7662029, and UGT2B7 rs7439366 were significantly associated with AT-DILI susceptibility. However, this conclusion should be interpreted with caution due to the low number of studies and the relatively small sample size.

Establishment of UGT1A1-knockout human iPS-derived hepatic organoids for UGT1A1-specific kinetics and toxicity evaluation

Uridine diphosphate glucuronosyltransferases (UGTs) are highly expressed in the liver and are involved in the metabolism of many drugs. In particular, UGT1A1 has a genetic polymorphism that causes decreased activity, leading to drug-induced hepatotoxicity. Therefore, an in vitro evaluation system that accurately predicts the kinetics of drugs involving UGT1A1 is required. However, there is no such evaluation system because of the absence of the UGT1A1-selective inhibitor. Here, using human induced pluripotent stem (iPS) cells, genome editing technology, and organoid technology, we generated UGT1A1-knockout human iPS hepatocyte-derived liver organoids (UGT1A1-KO i-HOs) as a model for UGT1A1-specific kinetics and toxicity evaluation. i-HOs showed higher gene expression of many drug-metabolizing enzymes including UGT1A1 than human iPS cell-derived hepatocyte-like cells (iPS-HLCs), suggesting that hepatic organoid technology improves liver functions. Wild-type (WT) i-HOs showed similar levels of UGT1A1 activity to primary human (cryopreserved) hepatocytes, while UGT1A1-KO i-HOs completely lost the activity. Additionally, to evaluate whether this model can be used to predict drug-induced hepatotoxicity, UGT1A1-KO i-HOs were exposed to SN-38, the active metabolite of irinotecan, an anticancer drug, and acetaminophen and confirmed that these cells could predict UGT1A1-mediated toxicity. Thus, we succeeded in generating model cells that enable evaluation of UGT1A1-specific kinetics and toxicity.

In vitro and in silico assessment of endocrine disrupting effects of food contaminants through pregnane X receptor

As a promiscuous xenobiotic receptor, pregnane X receptor (PXR) has been confirmed to participate in numerous physiological process. In addition to the conventional estrogen/androgen receptor, PXR also serves as an alternative target for environmental chemical contaminants. In this work, the PXR-mediated endocrine disrupting effects of typical food contaminants were explored. Firstly, the time-resolved fluorescence resonance energy transfer assays confirmed the PXR binding affinities of 2,2',4,4',5,5'-hexachlorobiphenyl, bis(2-ethylhexyl) phthalate, dibutyl phthalate, chlorpyrifos, bisphenol A, and zearalenone, with IC50 values ranging from 1.88 to 4284.00 nM. Then their PXR agonist activities were assessed by PXR-mediated CYP3A4 reporter gene assays. Subsequently, the regulation of gene expressions of PXR and its targets CYP3A4, UGT1A1, and MDR1 by these compounds was further investigated. Intriguingly, all the tested compounds interfered with these gene expressions, confirming their endocrine disrupting effects via PXR-mediated signaling. The compound-PXR-LBD binding interactions were explored by molecular docking and molecular dynamics simulations to unravel the structural basis of their PXR binding capacities. The weak intermolecular interactions are key players in stabilizing these compound-PXR-LBD complexes. During the simulation process, 2,2',4,4',5,5'-hexachlorobiphenyl remained stable while the other 5 compounds underwent relatively severe disturbances. In conclusion, these food contaminants might exhibit endocrine disrupting effects via PXR.

Salvia miltiorrhiza polysaccharides alleviates florfenicol-induced liver metabolic disorder in chicks by regulating drug and amino acid metabolic signaling pathways

Excessive and nonstandard use of florfenicol (FFC) can damage animal body, pollute ecological environment, and even harm human health. The toxic and side effects of FFC directly affect the production performance of poultry and the safe supply of chicken-related food. Salvia miltiorrhaza polysaccharides (SMPs) are natural macromolecular compounds, and were proved to have the effect of protecting animal liver. We used transcriptome and proteome sequencing technologies to study the effect of FFC on specific signal transduction pathways in chick livers and further explored the regulatory effect of SMPs on the above same signal pathways, and finally revealed the intervention effect and mechanism of SMPs on FFC-induced changes of liver function. The screened sequencing results were verified by qPCR and PRM methods. The results showed that FFC changed significantly 9 genes and 5 proteins in drug metabolism-cytochrome P450 signaling pathway, and the intervention of SMPs adjusted the expression levels of 5 genes and 4 proteins of the above factors. In glycine, serine and threonine metabolism signaling pathway, 8 genes and 8 proteins were significantly changed due to FFC exposure, and SMPs corrected the expression levels of 5 genes and 6 proteins to a certain extent. In conclusion, SMPs alleviated FFC-induced liver metabolic disorder in chicks by regulating the drug and amino acid metabolism pathway. This study is of great significance for promoting the healthy breeding of broilers and ensuring the safe supply of chicken-related products.

Oridonin alleviates hyperbilirubinemia through activating LXRα-UGT1A1 axis

Hyperbilirubinemia is a serious hazard to human health due to its neurotoxicity and lethality. So far, successful therapy for hyperbilirubinemia with fewer side effects is still lacking. In this study, we aimed to clarify the effects of oridonin (Ori), an active diterpenoid extracted from Rabdosia rubescens, on hyperbilirubinemia and revealed the underlying molecular mechanism in vivo and in vitro. Here, we showed that liver X receptor alpha (LXRα) deletion eliminated the protective effect of Ori on phenylhydrazine hydrochloride-induced hyperbilirubinemia mice, indicating that LXRα acted as a key target for Ori treatment of hyperbilirubinemia. Ori significantly increased the expression of LXRα and UDP-glucuronosyltransferase 1A1 (UGT1A1) in the liver of wild-type (WT) mice, which were lost in LXRα^-/- mice. Ori or LXR agonist GW3965 also reduced lipopolysaccharide/D-galactosamine-induced hyperbilirubinemia via activating LXRα/UGT1A1 in WT mice. Liver UGT1A1 enzyme activity was elevated by Ori or GW3965 in WT mice. Further, Ori up-regulated LXRα gene expression, increased its nuclear translocation and stimulated UGT1A1 promoter activity in HepG2 cells. After silencing LXRα by siRNA, Ori-induced UGT1A1 expression was markedly reduced in HepG2 cells and primary mouse hepatocytes. Taken together, Ori stimulated the transcriptional activity of LXRα, resulting in the up-regulation of UGT1A1. Therefore, Ori or its analogs might have the potential to treat hyperbilirubinemia-related diseases through modulating LXRα-UGT1A1 signaling.

The relationship between UGT1A1 gene & various diseases and prevention strategies

UDP-glucuronyltransferase 1A1 (UGT1A1) is a member of the Phase II metabolic enzyme family and the only enzyme that can metabolize detoxified bilirubin. Inactivation and very low activity of UGT1A1 in the liver can be fatal or lead to lifelong Gilbert's syndrome (GS) and Crigler-Najjar syndrome (CN). To date, more than one hundred UGT1A1 polymorphisms have been discovered. Although most UGT1A1 polymorphisms are not fatal, which diseases might be associated with low activity UGT1A1 or UGT1A1 polymorphisms? This scientific topic has been studied for more than a hundred years, there are still many uncertainties. Herein, this article will summarize all the possibilities of UGT1A1 gene-related diseases, including GS and CN, neurological disease, hepatobiliary disease, metabolic difficulties, gallstone, cardiovascular disease, Crohn's disease (CD) obesity, diabetes, myelosuppression, leukemia, tumorigenesis, etc., and provide guidance for researchers to conduct in-depth study on UGT1A1 gene-related diseases. In addition, this article not only summarizes the prevention strategies of UGT1A1 gene-related diseases, but also puts forward some insights for sharing.