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| Status |
Public on Mar 20, 2024 |
| Title |
Coactivator-independent vitamin D receptor signaling impairs intestinal calcium transport in mice, leading to severe rickets, which is not prevented by a diet high in calcium, phosphate, and lactose. |
| Organism |
Mus musculus |
| Experiment type |
Expression profiling by high throughput sequencing
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| Summary |
The vitamin D receptor (VDR) plays a critical role in the regulation of mineral and bone homeostasis. Upon binding of 1α,25-dihydroxyvitamin D3 to the VDR, the activation function 2 (AF2) domain repositions and recruits coactivators for the assembly of the transcriptional machinery required for gene transcription. In contrast to coactivator-induced transcriptional activation, the functional effects of coactivator-independent VDR signaling remain unclear. In humans, mutations in the AF2 domain are associated with hereditary vitamin D-resistant rickets, a genetic disorder characterized by impaired bone mineralization and growth. In the present study, we used mice with a systemic or conditional deletion of the VDR-AF2 domain (VdrΔAF2) to study coactivator-independent VDR signaling. We confirm that ligand-induced transcriptional activation was disabled because the mutant VDRΔAF2 protein was unable to interact with coactivators. Systemic VdrΔAF2 mice developed short, undermineralized bones with enlarged growth plates, a bone phenotype that was more pronounced than that of systemic Vdr knockout (Vdr-/-) mice. Interestingly, a rescue diet that is high in calcium, phosphate, and lactose, normalized this phenotype in Vdr-/-, but not in VdrΔAF2 mice. Our findings in osteoblast- and osteoclast-specific VdrΔAF2 mice did not recapitulate this bone phenotype indicating coactivator-independent VDR effects are more important in other organs. On the other hand, RNA-seq analysis of duodenum and kidney revealed a repression of VDR target genes in systemic VdrΔAF2 mice, which was not observed in Vdr-/- mice. These genes could provide new insights in the compensaory (re)absorption of minerals that are crucial for bone homeostasis. In summary, coactivator-independent VDR effects contribute to mineral and bone homeostasis.
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| Overall design |
To investigate the differential effects of co-activator independent VDR signaling versus absent VDR signaling on mineral homeostasis, we performed RNA seq analysis in duodenum and kidney samples of Vdr-/- and VdrAF2 mice. Herefor, we used 8-week-old female mice to obtain 6 Vdr wildtype samples, 4 Vdr-/- samples and 4 Vdr AF2 samples of two different tissues, duodenum and kidney, which makes 28 samples in total. Mice were maintained on a diet high in calcium, phosphate and lactose (Inotiv, TD.96348) to circumvent effects of hypocalcemia and hypophosphatema, at least in the Vdr-/- mice.
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| Citation missing |
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| Submission date |
Mar 06, 2024 |
| Last update date |
Mar 20, 2024 |
| Contact name |
Annemieke Verstuyf |
| E-mail(s) |
mieke.verstuyf@kuleuven.be
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| Organization name |
KU Leuven
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| Street address |
Herestraat 49 box 902
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| City |
Leuven |
| ZIP/Postal code |
3000 |
| Country |
Belgium |
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| Platforms (1) |
| GPL21103 |
Illumina HiSeq 4000 (Mus musculus) |
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| Samples (28)
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| Relations |
| BioProject |
PRJNA1084785 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE260988_raw_counts_duodenum.csv.gz |
425.0 Kb |
(ftp)(http) |
CSV |
| GSE260988_raw_counts_kidney.csv.gz |
399.1 Kb |
(ftp)(http) |
CSV |
SRA Run Selector |
| Raw data are available in SRA |
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