| 1. |
- Tremmel, Roman, et al.
(författare)
-
Hepatic Expression of the Na+-Taurocholate Cotransporting Polypeptide Is Independent from Genetic Variation
- 2022
-
Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 23:13
-
Tidskriftsartikel (refereegranskat)abstract
- The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 is important for the uptake of bile salts and selected drugs. Its inhibition results in increased systemic bile salt concentrations. NTCP is also the entry receptor for the hepatitis B/D virus. We investigated interindividual hepatic SLC10A1/NTCP expression using various omics technologies. SLC10A1/NTCP mRNA expression/protein abundance was quantified in well-characterized 143 human livers by real-time PCR and LC-MS/MS-based targeted proteomics. Genome-wide SNP arrays and SLC10A1 next-generation sequencing were used for genomic analyses. SLC10A1 DNA methylation was assessed through MALDI-TOF MS. Transcriptomics and untargeted metabolomics (UHPLC-Q-TOF-MS) were correlated to identify NTCP-related metabolic pathways. SLC10A1 mRNA and NTCP protein levels varied 44-fold and 10.4-fold, respectively. Non-genetic factors (e.g., smoking, alcohol consumption) influenced significantly NTCP expression. Genetic variants in SLC10A1 or other genes do not explain expression variability which was validated in livers (n = 50) from The Cancer Genome Atlas. The identified two missense SLC10A1 variants did not impair transport function in transfectants. Specific CpG sites in SLC10A1 as well as single metabolic alterations and pathways (e.g., peroxisomal and bile acid synthesis) were significantly associated with expression. Inter-individual variability of NTCP expression is multifactorial with the contribution of clinical factors, DNA methylation, transcriptional regulation as well as hepatic metabolism, but not genetic variation.
|
|
| 2. |
- Tremmel, Roman, et al.
(författare)
-
Non-genetic and epigenetic factors contribute to inter-individualvariability of the hepatic bile acid and drug transporter NTCP : Hepatic variability of the hepatic bile acid and drug transporter NTCP
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background and Purpose: The hepatic Na+-taurocholate cotransporting polypeptide NTCP/SLC10A1 plays an importantrole in the uptake of bile salts and drugs, and as key receptor for hepatitis B/D virus entry. NTCPinhibitors are investigated for treatment of HBV/HDV-infection. We performed a comprehensivemulti-omics approach to investigate underlying mechanisms of inter-individual variability ofNTCP expression in Caucasians.Experimental Approach: mRNA/protein expression of SLC10A1/NTCP was quantified in 143 well-characterized nontumorhuman liver samples by real-time PCR and LC-MS/MS-based targeted proteomics,respectively. Genetic variants were investigated using genome-wide SNP arrays and nextgenerationsequencing. DNA methylation of the SLC10A1 promoter region was investigatedthrough MALDI-TOF MS. Untargeted metabolomics of liver tissues was performed by UHPLC-QTOFMS.Key Results: The SLC10A1 mRNA expression showed a 44-fold variation in liver samples, whereas NTCPprotein expression varied 10.4-fold. Genome-wide association analyses and in-depth SLC10A1sequencing indicates that genetic variants either in SLC10A1 or other genes, cannot explainexpression variability. Only two missense SLC10A1 variants were identified. NTCP proteinexpression is significantly influenced by non-genetic factors (e.g. smoking, alcoholconsumption). DNA methylation analysis revealed a significant association of specific CpG-siteswith protein expression (p<0.05). Additionally, variable expression is associated with metabolicalterations determined through gene set enrichment and untargeted metabolomics. Findingswere validated partly in livers (n=50) from The Cancer Genome Atlas.Conclusion and Implications: Inter-individual variability of NTCP expression is multifactorial with a significant contribution ofDNA methylation. Functional genetic variants are negligible and may not limit targeting of NTCPby novel inhibitors for treatment of HBV/HDV-infection.
|
|
