AIM: To determine if novel bile acid transporters may be expressed in human tissues. METHODS: SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homolog...AIM: To determine if novel bile acid transporters may be expressed in human tissues. METHODS: SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homology search identified an EST (termed SLC10A4) that shares sequence identity with SLC10A1 and SLC10A2 (ASBT). We performed Northern blot analysis and RT-PCR to determine the tissue distribution of SLC10A4. SLC10A4 was cloned in frame with an epitope tag and overexpressed in CHO cells to determine cellular localization and functional analysis of bile acid uptake. RESULTS: Northern analysis revealed that SLC10A4 mRNA is ubiquitously expressed in human tissues with the highest levels of mRNA expression in brain, placenta, and liver. In SLC10A4-transfected CHO cells, immunoblotting analysis and immunofluorescence staining demonstrated a 49-kDa protein that is expressed at the plasma membrane and intracellular compartments. Functional analysis of SLC10A4 showed no significant taurocholate uptake in the presence of sodium when compared to untransfected CHO cells. CONCLUSION: To date, we have shown that this protein has no capacity to transport taurocholate relative to SLC10A1; however, given its ubiquitous tissue distribution, it may play a more active role in transporting other endogenous organic anions.展开更多
Oral administration is the best way for the most patients due to the good compliance,and intestinal epithelium is the main barrier of oral drug absorption.In order to overcome the small intestine epithelial barrier to...Oral administration is the best way for the most patients due to the good compliance,and intestinal epithelium is the main barrier of oral drug absorption.In order to overcome the small intestine epithelial barrier to orally deliver water-insoluble drugs,deoxycholic acid(DA),a substrate of the intestinal bile acid transporters,conjugated poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)(DA-PEOz-PLA)was designed and synthesized,and deoxycholic acid-modified polymeric micelles composed of DA-PEOz-PLA and mPEG-PLA were fabricated to encapsulate model drug coumarin 6(C6)based on intestinal bile acid pathway.The structure of DA-PEOz-PLA was confirmed using 1 H NMR and TLC,and the molecular weight measured by GPC was 10034 g/mol with a PDI of 1.51.The C6-loaded polymeric micelles with drug loading content of 0.085%were characterized to have 40.11 nm in diameter and uniform spherical morphology observed by TEM.Furthermore,the deoxycholic acid-modified polymeric micelles were demonstrated to further enhance the transmembrane transport efficiency.The mechanic study evidenced that anchorage of deoxycholic acid onto the micelles surface enriched their transcellular transport pathway.Therefore,the designed deoxycholic acid-modified polymeric micelles might have a promising potential for oral delivery of water-insoluble drugs.展开更多
基金Supported by National Institutes of Health Grant DK24031 (to NF. L.) and by the Mayo Foundation
文摘AIM: To determine if novel bile acid transporters may be expressed in human tissues. METHODS: SLC10A1 (NTCP) was used as a probe to search the NCBI database for homology to previously uncharacterized ESTs. The homology search identified an EST (termed SLC10A4) that shares sequence identity with SLC10A1 and SLC10A2 (ASBT). We performed Northern blot analysis and RT-PCR to determine the tissue distribution of SLC10A4. SLC10A4 was cloned in frame with an epitope tag and overexpressed in CHO cells to determine cellular localization and functional analysis of bile acid uptake. RESULTS: Northern analysis revealed that SLC10A4 mRNA is ubiquitously expressed in human tissues with the highest levels of mRNA expression in brain, placenta, and liver. In SLC10A4-transfected CHO cells, immunoblotting analysis and immunofluorescence staining demonstrated a 49-kDa protein that is expressed at the plasma membrane and intracellular compartments. Functional analysis of SLC10A4 showed no significant taurocholate uptake in the presence of sodium when compared to untransfected CHO cells. CONCLUSION: To date, we have shown that this protein has no capacity to transport taurocholate relative to SLC10A1; however, given its ubiquitous tissue distribution, it may play a more active role in transporting other endogenous organic anions.
基金The National Natural Science Foundation of China(Grant No.81673366).
文摘Oral administration is the best way for the most patients due to the good compliance,and intestinal epithelium is the main barrier of oral drug absorption.In order to overcome the small intestine epithelial barrier to orally deliver water-insoluble drugs,deoxycholic acid(DA),a substrate of the intestinal bile acid transporters,conjugated poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)(DA-PEOz-PLA)was designed and synthesized,and deoxycholic acid-modified polymeric micelles composed of DA-PEOz-PLA and mPEG-PLA were fabricated to encapsulate model drug coumarin 6(C6)based on intestinal bile acid pathway.The structure of DA-PEOz-PLA was confirmed using 1 H NMR and TLC,and the molecular weight measured by GPC was 10034 g/mol with a PDI of 1.51.The C6-loaded polymeric micelles with drug loading content of 0.085%were characterized to have 40.11 nm in diameter and uniform spherical morphology observed by TEM.Furthermore,the deoxycholic acid-modified polymeric micelles were demonstrated to further enhance the transmembrane transport efficiency.The mechanic study evidenced that anchorage of deoxycholic acid onto the micelles surface enriched their transcellular transport pathway.Therefore,the designed deoxycholic acid-modified polymeric micelles might have a promising potential for oral delivery of water-insoluble drugs.
