Bone phenotyping of murine hemochromatosis models with deficiencies of Hjv, Alk2, or Alk3: The influence of sex and the bone compartment

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Deniz Y Dogan - , Goethe University Frankfurt a.M. (Author)
  • Isabelle Hornung - , Goethe University Frankfurt a.M. (Author)
  • Mariateresa Pettinato - , IRCCS Hospital San Raffaele - Milano (Author)
  • Alessia Pagani - , IRCCS Hospital San Raffaele - Milano (Author)
  • Ulrike Baschant - , Department of Internal Medicine III, University Hospital Carl Gustav Carus Dresden (Author)
  • Guiscard Seebohm - , University Hospital Münster (Author)
  • Lorenz C Hofbauer - , Department of Internal Medicine III, University Hospital Carl Gustav Carus Dresden (Author)
  • Laura Silvestri - , Vita-Salute San Raffaele University (Author)
  • Martina Rauner - , Department of Internal Medicine III, University Hospital Carl Gustav Carus Dresden (Author)
  • Andrea U Steinbicker - , Goethe University Frankfurt a.M. (Author)

Abstract

Osteopenia is frequently observed in patients with iron overload, especially in those with HFE-dependent hereditary hemochromatosis (HH). Interestingly, not all mouse models of HH show bone loss, suggesting that iron overload alone may not suffice to induce bone loss. In this study, the bone phenotypes of Hjv-/- and hepatocyte-specific Alk2- and Alk3-deficient mice as additional mouse models of HH were investigated to further clarify, how high iron levels lead to bone loss and which signaling mechanisms are operational. Neither male nor female 12-week-old Hjv-/- mice had an altered trabecular or cortical bone mass or bone turnover, despite severe iron overload. Male 12-month-old Hjv-/- mice even presented with a higher femoral trabecular bone volume compared to wildtype mice. Similarly, female mice with hepatocyte-specific Alk2 or Alk3 deficiency did not show an altered bone phenotype at 3, 6, and 12 months of age. Male hepatocyte-specific Alk3-deficient mice also had a normal trabecular bone mass at all ages analyzed, despite showing increased bone resorption and decreased bone formation parameters. Interestingly, hepatocyte-specific Alk2-deficient mice showed reduced femoral trabecular bone at 6 months of age due to suppressed bone formation. Cortical thickness at the femur was reduced in both, 6-month-old male hepatocyte-specific Alk2- and Alk3-deficient mice. Raising hepatocyte-specific Alk2-deficient male mice on an iron-deficient diet rescued the bone phenotype. Taken together, despite iron overload, trabecular bone microarchitecture was not altered in mice deficient of Hjv or Alk3. Only male hepatocyte-specific Alk2-deficient mice showed site-specific lower trabecular and cortical bone mass at the femur, which was dependent on iron. Thus, bone loss does not correlate with the extent of iron overload in these mouse models, but may relate to the amount of iron-loaded macrophages, as precursors of osteoclasts, in the bone marrow.

Details

Original languageEnglish
Article numbere70179
Pages (from-to)e70179
JournalFASEB journal : official publication of the Federation of American Societies for Experimental Biology
Volume38
Issue number22
Publication statusPublished - 30 Nov 2024
Peer-reviewedYes

External IDs

Scopus 85209702263
ORCID /0000-0002-8691-8423/work/173517104
ORCID /0000-0002-6862-1650/work/173517153

Keywords

Keywords

  • Animals, Hemochromatosis/genetics, Male, Female, Mice, Disease Models, Animal, Hemochromatosis Protein/genetics, Activin Receptors, Type I/genetics, Activin Receptors, Type II/genetics, Phenotype, Mice, Knockout, Bone and Bones/metabolism, Mice, Inbred C57BL, Iron Overload/metabolism, Sex Factors, GPI-Linked Proteins