Altered expression of iron regulatory proteins with aging is associated with transient hepatic iron accumulation after environmental heat stress

Steven Alfred Bloomer, Okhee Han, Kevin C. Kregel, Kyle E. Brown

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

An increasing body of evidence suggests that dysregulation of iron metabolism contributes to age-related pathologies. We have previously observed increased hepatic iron with aging, and that environmental heat stress stimulates a further increase in iron and oxidative liver injury in old rats. The purpose of this study was to determine a mechanism for the increase in hepatic iron in old rats after heat stress. Young (6. mo) and old (24. mo) Fischer 344 rats were exposed to two heating bouts separated by 24. h. Livers were harvested after the second heat stress, and protein levels of the iron import protein, transferrin receptor-1 (TFR1), and the iron export protein, ferroportin (Fpn) were determined by immunoblot. In the nonheated condition, old rats had lower TFR1 expression, and higher Fpn expression. After heat stress, TFR1 declined in the old rats, and iron chelation studies demonstrated that this decline was dependent on a hyperthermia-induced increase in iron. TFR1 did not change in the young rats after heat stress. Since TFR1 is inversely regulated by iron, our results suggest that the increase in intracellular iron with aging and heat stress lower TFR1 expression. Fpn expression increased in both age groups after heat stress, but this response was delayed in old rats. This delay in the induction of an iron exporter suggests a mechanism for the increase in hepatic iron and oxidative injury after heat stress in aged organisms.

Original languageEnglish (US)
Pages (from-to)19-26
Number of pages8
JournalBlood Cells, Molecules, and Diseases
Volume52
Issue number1
DOIs
StatePublished - Jan 1 2014

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Iron-Regulatory Proteins
Iron
Hot Temperature
Transferrin Receptors
Liver
Heat-Shock Response
Induced Hyperthermia
Inbred F344 Rats
Wounds and Injuries
Heat-Shock Proteins
Heating

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Molecular Biology
  • Hematology
  • Cell Biology

Cite this

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abstract = "An increasing body of evidence suggests that dysregulation of iron metabolism contributes to age-related pathologies. We have previously observed increased hepatic iron with aging, and that environmental heat stress stimulates a further increase in iron and oxidative liver injury in old rats. The purpose of this study was to determine a mechanism for the increase in hepatic iron in old rats after heat stress. Young (6. mo) and old (24. mo) Fischer 344 rats were exposed to two heating bouts separated by 24. h. Livers were harvested after the second heat stress, and protein levels of the iron import protein, transferrin receptor-1 (TFR1), and the iron export protein, ferroportin (Fpn) were determined by immunoblot. In the nonheated condition, old rats had lower TFR1 expression, and higher Fpn expression. After heat stress, TFR1 declined in the old rats, and iron chelation studies demonstrated that this decline was dependent on a hyperthermia-induced increase in iron. TFR1 did not change in the young rats after heat stress. Since TFR1 is inversely regulated by iron, our results suggest that the increase in intracellular iron with aging and heat stress lower TFR1 expression. Fpn expression increased in both age groups after heat stress, but this response was delayed in old rats. This delay in the induction of an iron exporter suggests a mechanism for the increase in hepatic iron and oxidative injury after heat stress in aged organisms.",
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Altered expression of iron regulatory proteins with aging is associated with transient hepatic iron accumulation after environmental heat stress. / Bloomer, Steven Alfred; Han, Okhee; Kregel, Kevin C.; Brown, Kyle E.

In: Blood Cells, Molecules, and Diseases, Vol. 52, No. 1, 01.01.2014, p. 19-26.

Research output: Contribution to journalArticle

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