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Intestinal DMT1 cotransporter is down-regulated by hepcidin via proteasome internalization and degradation.
Gastroenterology. 2011 Apr; 140(4):1261-1271.e1.G

Abstract

BACKGROUNDS & AIMS

The mechanism by which hepcidin regulates iron export from macrophages has been well established and is believed to involve degradation of ferroportin. However, in the small intestine, hepcidin's mechanisms of action are not known. We studied human polarized intestinal (Caco-2/TC7) cells and mouse duodenal segments, ex vivo, to investigate the molecular mechanisms by which hepcidin down-regulates intestinal transepithelial iron transport.

METHODS

Iron transport was analyzed using ⁵⁵FeNTA. Expression of Divalent Metal Transporter 1 (DMT1) and ferroportin was evaluated by reverse-transcription quantitative polymerase chain reaction and immunoblotting. Videomicroscopy analysis was performed on live cells that expressed either DMT1 or ferroportin fused to green fluorescent protein.

RESULTS

In Caco-2/TC7 cells, physiologic doses of hepcidin (50-1000 nmol/L) inhibited transport of ⁵⁵Fe in a dose-dependent manner; a half-maximum effect was observed at 75-100 nmol/L. However, 200 nmol/L hepcidin induced a significant decrease in DMT1 protein expression but no change in ferroportin protein levels, unlike macrophages. This result was confirmed ex vivo in isolated duodenal segments: 200 nmol/L hepcidin induced a significant reduction in iron transport and DMT1 protein levels but no change in ferroportin levels. In Caco-2/TC7 cells, the effect of hepcidin on the DMT1 protein level was completely abolished in the presence of a proteasome inhibitor (MG-132); DMT1 ubiquitination was induced by the addition of hepcidin.

CONCLUSIONS

An acute increase in hepcidin concentration reduces intestinal iron absorption through ubiquitin-dependent proteasome degradation of DMT1.

Authors+Show Affiliations

INSERM U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Université Paris Diderot, site Bichat, Paris, France. carole.lagnel@univ-rouen.frNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21199652

Citation

Brasse-Lagnel, Carole, et al. "Intestinal DMT1 Cotransporter Is Down-regulated By Hepcidin Via Proteasome Internalization and Degradation." Gastroenterology, vol. 140, no. 4, 2011, pp. 1261-1271.e1.
Brasse-Lagnel C, Karim Z, Letteron P, et al. Intestinal DMT1 cotransporter is down-regulated by hepcidin via proteasome internalization and degradation. Gastroenterology. 2011;140(4):1261-1271.e1.
Brasse-Lagnel, C., Karim, Z., Letteron, P., Bekri, S., Bado, A., & Beaumont, C. (2011). Intestinal DMT1 cotransporter is down-regulated by hepcidin via proteasome internalization and degradation. Gastroenterology, 140(4), 1261-e1. https://doi.org/10.1053/j.gastro.2010.12.037
Brasse-Lagnel C, et al. Intestinal DMT1 Cotransporter Is Down-regulated By Hepcidin Via Proteasome Internalization and Degradation. Gastroenterology. 2011;140(4):1261-1271.e1. PubMed PMID: 21199652.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intestinal DMT1 cotransporter is down-regulated by hepcidin via proteasome internalization and degradation. AU - Brasse-Lagnel,Carole, AU - Karim,Zoubida, AU - Letteron,Philippe, AU - Bekri,Soumeya, AU - Bado,André, AU - Beaumont,Carole, Y1 - 2011/01/01/ PY - 2010/03/02/received PY - 2010/12/07/revised PY - 2010/12/20/accepted PY - 2011/1/5/entrez PY - 2011/1/5/pubmed PY - 2011/5/27/medline SP - 1261 EP - 1271.e1 JF - Gastroenterology JO - Gastroenterology VL - 140 IS - 4 N2 - BACKGROUNDS & AIMS: The mechanism by which hepcidin regulates iron export from macrophages has been well established and is believed to involve degradation of ferroportin. However, in the small intestine, hepcidin's mechanisms of action are not known. We studied human polarized intestinal (Caco-2/TC7) cells and mouse duodenal segments, ex vivo, to investigate the molecular mechanisms by which hepcidin down-regulates intestinal transepithelial iron transport. METHODS: Iron transport was analyzed using ⁵⁵FeNTA. Expression of Divalent Metal Transporter 1 (DMT1) and ferroportin was evaluated by reverse-transcription quantitative polymerase chain reaction and immunoblotting. Videomicroscopy analysis was performed on live cells that expressed either DMT1 or ferroportin fused to green fluorescent protein. RESULTS: In Caco-2/TC7 cells, physiologic doses of hepcidin (50-1000 nmol/L) inhibited transport of ⁵⁵Fe in a dose-dependent manner; a half-maximum effect was observed at 75-100 nmol/L. However, 200 nmol/L hepcidin induced a significant decrease in DMT1 protein expression but no change in ferroportin protein levels, unlike macrophages. This result was confirmed ex vivo in isolated duodenal segments: 200 nmol/L hepcidin induced a significant reduction in iron transport and DMT1 protein levels but no change in ferroportin levels. In Caco-2/TC7 cells, the effect of hepcidin on the DMT1 protein level was completely abolished in the presence of a proteasome inhibitor (MG-132); DMT1 ubiquitination was induced by the addition of hepcidin. CONCLUSIONS: An acute increase in hepcidin concentration reduces intestinal iron absorption through ubiquitin-dependent proteasome degradation of DMT1. SN - 1528-0012 UR - https://www.unboundmedicine.com/medline/citation/21199652/Intestinal_DMT1_cotransporter_is_down_regulated_by_hepcidin_via_proteasome_internalization_and_degradation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0016-5085(10)01882-2 DB - PRIME DP - Unbound Medicine ER -