The Assay of Vitamins B and G as Influenced by Coprophagy

Guerrant, N. B.; Dutcher, R. Adams

doi:10.1016/s0021-9258(18)76155-3

Cited by 1,106 publications

(4 citation statements)

References 16 publications

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“…), and Fusobacter (Fusobacterium varium) appear to be the main producers of the vitamin (23). Studies with human subjects and rodents have shown that the large intestine is capable of absorbing luminal vitamin B1 (reviewed in 18; also 19,24,25). This was confirmed in studies in our laboratory utilizing human colonic epithelial cells and colonic apical membrane vesicle preparations isolated from the colon of organ donors (20,26,27).…”

Section: Introductionmentioning

confidence: 58%

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Hypoxia inhibits colonic uptake of the microbiota-generated forms of vitamin B1 via HIF-1α-mediated transcriptional regulation of their transporters

Sabui

Ramamoorthy

Romero

et al. 2022

Journal of Biological Chemistry

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show abstract

Section: Introductionmentioning

confidence: 58%

“…( 17 ); also Refs. ( 18 , 23 , 24 )). This was confirmed in studies in our laboratory utilizing human colonic epithelial cells and colonic apical membrane vesicle preparations isolated from the colon of organ donors ( 19 , 25 , 26 ).…”

mentioning

confidence: 99%

Hypoxia inhibits colonic uptake of the microbiota-generated forms of vitamin B1 via HIF-1α-mediated transcriptional regulation of their transporters

Sabui

Ramamoorthy

Romero

et al. 2022

Journal of Biological Chemistry

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“…The large intestinal microbiota generates considerable amounts of thiamin, which exist in both the free and TPP forms (1,7,8,18). Transport of the free thiamin in the large intestine has been well characterized (25,28), but less is known about the transport of TPP.…”

Section: Discussionmentioning

confidence: 99%

“…Most dietary thiamin exists as TPP, a form that is hydrolyzed to free thiamin before absorption by small intestinal phosphatases (21,27,28); this is followed by internalization of the free thiamine into absorptive cells via a process that is carrier-mediated and involves the SLC19A2 (THTR-1) and SLC19A3 (THTR-2) systems (6, 19 -21, 23, 27, 28, 33). The microbiota-generated thiamin exists in both the free and the TPP forms (1,7,8,28). Previous studies from our laboratory have shown that both forms of the vitamin are absorbed in the large intestine, with absorption of the free thiamin being mediated by the SLC19A2 and SLC19A3 systems (25,26,28), while that of TPP by the SLC44A4 system (TPPT) (13,16).…”

Section: Introductionmentioning

confidence: 96%

Molecular mechanisms involved in the adaptive regulation of the colonic thiamin pyrophosphate uptake process

Anandam

Srinivasan

Subramanian

et al. 2017

American Journal of Physiology-Cell Physiology

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A considerable amount of the thiamin generated by gut microbiota exists in the form of thiamin pyrophosphate (TPP). We have previously shown that human colonocytes possess an efficient carrier-mediated uptake process for TPP that involves the SLC44A4 system and this uptake process is adaptively regulated by prevailing extracellular TPP level. Little is known about the molecular mechanisms that mediate this adaptive regulation. We addressed this issue using human-derived colonic epithelial NCM460 cells and mouse colonoids as models. Maintaining NCM460 cells in the presence of a high level of TPP (1 mM) for short (2 days)- and long-term (9 days) periods was found to lead to a significant reduction in [H] TPP uptake compared with cells maintained in its absence. Short-term exposure showed no changes in level of expression of SLC44A4 protein in total cell homogenate (although there was a decreased expression in the membrane fraction), mRNA, and promoter activity. However, a significant reduction in the level of expression of the SLC44A4 protein, mRNA, and promoter activity was observed upon long-term maintenance with the substrate. Similar changes in Slc44a4 mRNA expression were observed when mouse colonoids were maintained with TPP for short- and long-term periods. Expression of the transcription factors ELF3 and CREB-1 (which drive the SLC44A4 promoter) following long-term exposure was unchanged, but their binding affinity to the promoter was decreased and specific histone modifications were also observed. These studies demonstrate that, depending on the period of exposure, different mechanisms are involved in the adaptive regulation of colonic TPP uptake by extracellular substrate level.

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The Biosynthesis of Riboflavin in Man

Najjar¹

1944

JAMA

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The Assay of Vitamins B and G as Influenced by Coprophagy

Cited by 1,106 publications

References 16 publications

Hypoxia inhibits colonic uptake of the microbiota-generated forms of vitamin B1 via HIF-1α-mediated transcriptional regulation of their transporters

Hypoxia inhibits colonic uptake of the microbiota-generated forms of vitamin B1 via HIF-1α-mediated transcriptional regulation of their transporters

Molecular mechanisms involved in the adaptive regulation of the colonic thiamin pyrophosphate uptake process

The Biosynthesis of Riboflavin in Man

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