PMID- 14615284
OWN - NLM
STAT- MEDLINE
DCOM- 20040316
LR  - 20131121
IS  - 0193-1857 (Print)
IS  - 0193-1857 (Linking)
VI  - 286
IP  - 3
DP  - 2004 Mar
TI  - Expression and functional contribution of hTHTR-2 in thiamin absorption in human 
      intestine.
PG  - G491-8
AB  - The aim of this study was to investigate expression and relative contribution of 
      human thiamin transporter (hTHTR)-2 toward overall carrier-mediated thiamin 
      uptake by human intestinal epithelial cells. Northern blot analysis showed that 
      the message of the hTHTR-2 is expressed along the native human gastrointestinal 
      tract with highest expression being in the proximal part of small intestine. 
      hTHTR-2 protein was found, by Western blot analysis, to be expressed at the 
      brush-border membrane (BBM), but not at the basolateral membrane, of native human 
      enterocytes. This pattern of expression was confirmed in studies using a fusion 
      protein of hTHTR-2 with the enhanced green fluorescent protein (hTHTR2-EGFP) 
      expressed in living Caco-2 cells grown on filter. Pretreating Caco-2 cells (which 
      also express the hTHTR-2 at RNA and protein levels) with hTHTR-2 gene-specific 
      small interfering RNA (siRNA) led to a significant (P < 0.01) and specific 
      inhibition (48%) in carrier-mediated thiamin uptake. Similarly, pretreating 
      Caco-2 cells with siRNA that specifically target hTHTR-1 (which is expressed in 
      Caco-2 cells) also significantly (P < 0.01) and specifically inhibited (by 56%) 
      carrier-mediated thiamin uptake. When Caco-2 cells were pretreated with siRNAs 
      against both hTHTR-2 and hTHTR-1 genes, an almost complete inhibition in 
      carrier-mediated thiamin uptake was observed. These results show that the message 
      of hTHTR-2 is expressed along the human gastrointestinal tract and that 
      expression of its protein in intestinal epithelia is mainly localized to the 
      apical BBM domain. In addition, results show that this transporter plays a 
      significant role in carrier-mediated thiamin uptake in human intestine.
FAU - Said, Hamid M
AU  - Said HM
AD  - Veterans Affairs Medical Center-151, Long Beach, and University of California, 
      Irvine, USA. hmsaid@uci.edu
FAU - Balamurugan, Krishnaswamy
AU  - Balamurugan K
FAU - Subramanian, Veedamali S
AU  - Subramanian VS
FAU - Marchant, Jonathan S
AU  - Marchant JS
LA  - eng
GR  - DK-56061/DK/NIDDK NIH HHS/United States
GR  - DK-58057/DK/NIDDK NIH HHS/United States
GR  - DK-63750/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
DEP - 20031113
PL  - United States
TA  - Am J Physiol Gastrointest Liver Physiol
JT  - American journal of physiology. Gastrointestinal and liver physiology
JID - 100901227
RN  - 0 (DNA Primers)
RN  - 0 (Membrane Transport Proteins)
RN  - 0 (SLC19A2 protein, human)
RN  - 0 (SLC19A3 protein, human)
RN  - 63231-63-0 (RNA)
RN  - X66NSO3N35 (Thiamine)
SB  - IM
MH  - Blotting, Northern
MH  - Blotting, Western
MH  - Caco-2 Cells
MH  - DNA Primers
MH  - Epithelial Cells/metabolism
MH  - Humans
MH  - Intestinal Absorption/*genetics/*physiology
MH  - Kinetics
MH  - Membrane Transport Proteins/*genetics
MH  - RNA/biosynthesis/genetics
MH  - Reverse Transcriptase Polymerase Chain Reaction
MH  - Thiamine/*metabolism
MH  - Transfection
EDAT- 2003/11/15 05:00
MHDA- 2004/03/17 05:00
CRDT- 2003/11/15 05:00
PHST- 2003/11/15 05:00 [pubmed]
PHST- 2004/03/17 05:00 [medline]
PHST- 2003/11/15 05:00 [entrez]
AID - 00361.2003 [pii]
AID - 10.1152/ajpgi.00361.2003 [doi]
PST - ppublish
SO  - Am J Physiol Gastrointest Liver Physiol. 2004 Mar;286(3):G491-8. doi: 
      10.1152/ajpgi.00361.2003. Epub 2003 Nov 13.