ABCB4

UNLABELLED: ATP-binding cassette (ABC) transporters expressed at the blood-brain barrier (BBB) impede delivery of therapeutic agents to the brain, including agents to treat neurodegenerative diseases and primary and metastatic brain cancers. Two transporters, P-glycoprotein (P-gp, ABCB1) and ABCG2, are highly expressed at the BBB and are responsible for the efflux of numerous clinically useful chemotherapeutic agents, including irinotecan, paclitaxel, and doxorubicin. Based on a previous mouse model, we have generated transgenic zebrafish in which expression of NanoLuciferase (NanoLuc) is controlled by the promoter of glial fibrillary acidic protein, leading to expression in zebrafish glia...

BACKGROUND & AIMS: The nuclear receptor farnesoid X receptor (FXR) is a key regulator of hepatic bile acid (BA) and lipid metabolism, inflammation and fibrosis. Here, we aimed to explore the potential of cilofexor (GS-9674), a non-steroidal FXR agonist, as a therapeutic approach for counteracting features of cholestatic liver injury by evaluating its efficacy and mechanisms in the Mdr2/Abcb4 knockout (-/- ) mouse model of sclerosing cholangitis. METHODS: FVB/N wild-type and Mdr2 -/- or BALB/c wild-type and Mdr2 -/- mice were treated with 0, 10, 30 or 90 mg/kg cilofexor by gavage every 24 h for 10 weeks...

A 36-year-old patient presented with severe early-onset obstetric cholestasis on a background of having pre-term induction of labor at 33 weeks during her only previous pregnancy. The patient had significantly abnormal liver biochemistry with a bilirubin of 78 µmol/L, ALP of 318 u/L, ALT of 280 µmol/L, and bile acid levels of 420 µmol/L. The patient received ursodeoxycholic acid 750 mg 3 times a day, rifampicin 500 mg twice a day, aspirin 150 mg once a day, and metformin 500 mg 3 times a day...

BACKGROUND: Low phospholipid-associated cholelithiasis (LPAC) syndrome is a rare genetic cause of hepatolithiasis. A pathogenic variant of the ABCB4 gene is reported in half of all patients. Ursodeoxycholic acid (UDCA) is the only drug approved. However, in some patients, UDCA fails to prevent recurrence of symptoms and complications. Experimental evidence suggests that agonists of the farnesoid-X receptor (FXR), the main transcription factor regulating ABCB4, may be beneficial in this context...

BACKGROUND: ABCB4 gene (OMIM *171060) variant is associated with a wide clinical spectrum of hepatobiliary diseases, including familial intrahepatic cholestasis of pregnancy (ICP), progressive familial intrahepatic cholestasis type 3 (PFIC3), and neonatal hyperbilirubinemia due to impaired protection of the bile duct. The majority of reported cases, however, were missense or nonsense variants, with few deletion variant findings in the Chinese population. METHOD: We performed whole genome sequencing and confirmed it with Sanger sequencing of the proband infant and his families...

BACKGROUND & AIMS: Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare liver disease caused by biallelic variations in ABCB4 . Data reporting on the impact of genotype and of response to ursodeoxycholic acid (UDCA) therapy on long-term outcomes are scarce. METHODS: We retrospectively describe a cohort of 38 patients with PFIC3 with a median age at last follow-up of 19.5 years (range 3.8-53.8). RESULTS: Twenty patients presented with symptoms before 1 year of age...

OBJECTIVES: To report the mutational landscape of a clinically diagnosed cohort of paediatric patients with cholestasis liver diseases. METHODS: The retrospective study was conducted at the University of Child Health Sciences, The Children Hospital, Lahore, Pakistan, from December 10, 2021, to March 31, 2022, and comprised data collected from the Paediatric Gastroenterology and Hepatology unit on demographics, clinical and laboratory findings related to children of either gender aged <12 years and diagnosed with cholestatic liver disease from July 2018 to June 2021...

The ATP-binding cassette subfamily B member 1 (ABCB1), encoding a multidrug transporter referred to as P-glycoprotein (Pgp), plays a critical role in the efflux of xenobiotics in humans and is implicated in cancer resistance to chemotherapy. Therefore, developing high-throughput animal models to screen for Pgp function and bioavailability of substrates and inhibitors is paramount. Here, we generated and validated a zebrafish knockout line of abcb4, a human Pgp transporter homolog. CRISPR/Cas9 genome editing technology was deployed to generate a frameshift mutation in exon 4 of zebrafish abcb4...

BACKGROUND: Gene mutations in ATP-binding cassette, subfamily B ( ABCB4 ) lead to autosomal recessive disorders. Primary light amyloidosis is a rare and incurable disease. Here, we report a rare case of liver cirrhosis caused by ABCB4 gene mutation combined with primary light amyloidosis. CASE SUMMARY: We report a case of a 25-year-old female who was hospitalized due to recurrent abdominal pain caused by calculous cholecystitis and underwent cholecystectomy. Pathological examination of the liver tissue suggested liver cirrhosis with bile duct injury...

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare cholestatic liver disease with autosomal recessive inheritance caused by mutations in the ABCB4 gene. The clinical presentation of PFIC3 varies significantly, displaying incomplete penetrance without clear genotype-phenotype correlations. As such, the suitability of living-related liver donation for children with advanced disease has been questioned. We report here the long-term follow-up of a patient with PFIC3 resulting in decompensated cirrhosis at 11 years who successfully underwent living donor liver transplantation from his father, who carried the same ABCB4 homozygous mutation...

BACKGROUND & AIMS: Glucagon-like peptide (GLP)-2 may exert antifibrotic effects on hepatic stellate cells (HSCs). Thus, we aimed to test whether application of the GLP-2 analogue teduglutide has hepatoprotective and antifibrotic effects in the Mdr2/Abcb4-/- mouse model of sclerosing cholangitis displaying hepatic inflammation and fibrosis. METHODS: Mdr2-/- mice were injected daily for 4 weeks with teduglutide followed by gene expression profiling (bulk liver; isolated HSCs) and immunohistochemistry...

The ATP-binding cassette subfamily B member 1 (ABCB1), encoding a multidrug transporter referred to as P-glycoprotein (Pgp), plays a critical role in the efflux of xenobiotics in humans and is implicated in cancer resistance to chemotherapy. Therefore, developing high throughput animal models to screen for Pgp function and bioavailability of substrates and inhibitors is paramount. Here, we generated and validated a zebrafish knockout line of abcb4 , a human Pgp transporter homolog. CRISPR/Cas9 genome editing technology was deployed to generate a frameshift mutation in exon 4 of zebrafish abcb4 ...

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a rare genetic disorder that results from defective mechanisms of bile secretion. We aim to describe different types of PFIC and their clinical features, treatment modalities, and outcomes in Saudi Arabia. Patients and Methods . This is a retrospective study of all patients diagnosed with PFIC at King Faisal Specialist Hospital and Research Center in Riyadh from January 1, 2002, to December 31, 2021. All relevant information was collected from patient charts and transferred into the REDcap® database for statistical analysis...

The prevalence of NAFLD and NASH is increasing worldwide, and there is no approved medical treatment until now. Evidence has emerged that interfering with bile acid metabolism may lead to improvement in NASH. In this study, 28 patients with elevated cholestatic liver function tests (especially GGT) were screened for bile acid gene polymorphisms and treated with UDCA. All patients had a bile acid gene polymorphism in ABCB4 or ABCB11 . Treatment with UDCA for 12 months significantly reduced GGT in all patients and ALT in homozygous patients...

AIMS: ATP-binding cassette transporters are important proteins in regulating bile constituent transport between hepatocytes and the bile canalicular system. Dysfunctional transporters lead to accumulation of toxic bile components within hepatocytes or the biliary system, known as cholestasis, resulting in liver damage. It has been previously reported that two particular ATP-binding cassette transporters, ABCB4 and ABCB11, have altered expression in patients with primary sclerosing cholangitis (PSC)...

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a group of rapidly progressive autosomal recessive disorders characterized by intrahepatic cholestasis. PFIC-3 is caused by mutations in the ATP-binding cassette subfamily B member 4 gene (ABCB4), which encodes multidrug resistance protein 3 (MDR3/ABCB4). Patients are usually in infancy or childhood, but cirrhosis and portal hypertension may be the first manifestation in older children or young adults. CASE PRESENTATION: A 25-year-old young woman with recurrent abnormal hepatic function was mainly characterized by increased gamma glutamyl transpeptidase (GGT) and bile acid with cryptogenic cirrhosis...

BACKGROUND AND AIM: Gene defects contribute to the aetiology of intrahepatic cholestasis. We aimed to explore the outcome of whole-exome sequencing (WES) in a cohort of 51 patients with this diagnosis. PATIENTS AND METHODS: Both paediatric (n = 33) and adult (n = 18) patients with cholestatic liver disease of unknown aetiology were eligible. WES was used for reassessment of 34 patients (23 children) without diagnostic genotypes in ABCB11, ATP8B1, ABCB4 or JAG1 demonstrable by previous Sanger sequencing, and for primary assessment of additional 17 patients (10 children)...

A principal protective component of the mammalian blood-brain barrier (BBB) is the high expression of the multidrug efflux transporters P-glycoprotein (P-gp, encoded by ABCB1 ) and ABCG2 (encoded by ABCG2 ) on the luminal surface of endothelial cells. The zebrafish P-gp homolog Abcb4 is expressed at the BBB and phenocopies P-gp. Comparatively little is known about the four zebrafish homologs of the human ABCG2 gene: abcg2a, abcg2b, abcg2c , and abcg2d . Here we report the functional characterization and brain tissue distribution of zebrafish ABCG2 homologs...

OBJECTIVE: To gain mechanistic insights into adverse effects of maternal hyperglycemia on the liver of neonates, we performed a multi-omics analysis of liver tissue from piglets developed in genetically diabetic (mutant INS gene induced diabetes of youth; MIDY) or wild-type (WT) pigs. METHODS: Proteome, metabolome and lipidome profiles of liver and clinical parameters of serum samples from 3-day-old WT piglets (n=9) born to MIDY mothers (PHG) were compared with those of WT piglets (n=10) born to normoglycemic mothers (PNG)...

The chronic myelogenous leukemia cell line, K562/ADM is derived from the K562 cell line, which is resistant to doxorubicin (alias, adriamycin: ADM). P-glycoprotein levels are significantly higher in K562/ADM cells than in K562 cells. The overexpression of p-glycoprotein has been shown to cause drug resistance. Therefore, the present study investigated a novel mechanism underlying the drug resistance of K562/ADM cells. A gene ontology analysis demonstrated that the expression of solute carrier (SLC)-mediated transmembrane transport genes was significantly higher in K562/ADM cells than in K562 cells...