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Deletion of IFT80 Impairs Epiphyseal and Articular Cartilage Formation Due to Disruption of Chondrocyte Differentiation.

Yuan X, Yang S - PLoS ONE (2015)

Bottom Line: Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development.Loss of IFT80 in the embryonic stage resulted in short limbs at birth.These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Biology, School of Dental Medicine, University of Buffalo, State University of New York, Buffalo, NY, United States of America.

ABSTRACT
Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development. Partial loss of IFT80 function leads Jeune asphyxiating thoracic dystrophy (JATD) or short-rib polydactyly (SRP) syndrome type III, displaying narrow thoracic cavity and multiple cartilage anomalies. However, it is unknown how IFT80 regulates cartilage formation. To define the role and mechanism of IFT80 in chondrocyte function and cartilage formation, we generated a Col2α1; IFT80f/f mouse model by crossing IFT80f/f mice with inducible Col2α1-CreER mice, and deleted IFT80 in chondrocyte lineage by injection of tamoxifen into the mice in embryonic or postnatal stage. Loss of IFT80 in the embryonic stage resulted in short limbs at birth. Histological studies showed that IFT80-deficient mice have shortened cartilage with marked changes in cellular morphology and organization in the resting, proliferative, pre-hypertrophic, and hypertrophic zones. Moreover, deletion of IFT80 in the postnatal stage led to mouse stunted growth with shortened growth plate but thickened articular cartilage. Defects of ciliogenesis were found in the cartilage of IFT80-deficient mice and primary IFT80-deficient chondrocytes. Further study showed that chondrogenic differentiation was significantly inhibited in IFT80-deficient mice due to reduced hedgehog (Hh) signaling and increased Wnt signaling activities. These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.

No MeSH data available.


Related in: MedlinePlus

Deletion of IFT80 in chondrocytes caused impaired Hh signaling, and enhanced Wnt signaling activity.Primary chondrocytes were derived from P10 IFT80f/f and Col2α1; IFT80f/f mice, which were administered tamoxifen at P4-7. (A) Reporter assay showing Gli responsive luciferase (8×Gli-Luc) activity. Shh (1 μg/mL) treatment resulted in significant increases in luciferase activity in IFT80f/f chondrocytes, whereas less stimulation with Shh was observed in the Col2α1; IFT80f/f chondrocytes (n = 3). (B) Wnt luciferase reporter assay with or without Wnt3a stimulation. 100 ng/mL Wnt3a significantly promoted higher luciferase activity in Col2α1; IFT80f/f chondrocytes compared to IFT80f/f chondrocytes (n = 3).
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pone.0130618.g008: Deletion of IFT80 in chondrocytes caused impaired Hh signaling, and enhanced Wnt signaling activity.Primary chondrocytes were derived from P10 IFT80f/f and Col2α1; IFT80f/f mice, which were administered tamoxifen at P4-7. (A) Reporter assay showing Gli responsive luciferase (8×Gli-Luc) activity. Shh (1 μg/mL) treatment resulted in significant increases in luciferase activity in IFT80f/f chondrocytes, whereas less stimulation with Shh was observed in the Col2α1; IFT80f/f chondrocytes (n = 3). (B) Wnt luciferase reporter assay with or without Wnt3a stimulation. 100 ng/mL Wnt3a significantly promoted higher luciferase activity in Col2α1; IFT80f/f chondrocytes compared to IFT80f/f chondrocytes (n = 3).

Mentions: To gain further insight into the molecular mechanisms, we characterized the activation of Hh and Wnt signaling pathways, which are regulated by cilia or cilia related proteins [36, 37]. By performing a reporter assay using a p8×Gli-Luc construct [33], we found that stimulation with Shh resulted in a 3-fold increase in the Gli-responsive luciferase activity in IFT80f/f chondrocytes (Fig 8A). However, this activity significantly decreased in Col2α1; IFT80f/f chondrocytes (Fig 8A), indicating that Hh signaling activity is impaired. We also studied the role of IFT80 in Wnt signaling by performing a reporter assay with the M50 Super 8×TOPFlash construct. Wnt3a led to about 1.5-fold increase in luciferase activity in IFT80f/f chondrocytes, but almost 3-fold increase was found in Col2α1; IFT80f/f chondrocytes (Fig 8B), suggesting that loss of IFT80 promotes Wnt signaling pathway transduction.


Deletion of IFT80 Impairs Epiphyseal and Articular Cartilage Formation Due to Disruption of Chondrocyte Differentiation.

Yuan X, Yang S - PLoS ONE (2015)

Deletion of IFT80 in chondrocytes caused impaired Hh signaling, and enhanced Wnt signaling activity.Primary chondrocytes were derived from P10 IFT80f/f and Col2α1; IFT80f/f mice, which were administered tamoxifen at P4-7. (A) Reporter assay showing Gli responsive luciferase (8×Gli-Luc) activity. Shh (1 μg/mL) treatment resulted in significant increases in luciferase activity in IFT80f/f chondrocytes, whereas less stimulation with Shh was observed in the Col2α1; IFT80f/f chondrocytes (n = 3). (B) Wnt luciferase reporter assay with or without Wnt3a stimulation. 100 ng/mL Wnt3a significantly promoted higher luciferase activity in Col2α1; IFT80f/f chondrocytes compared to IFT80f/f chondrocytes (n = 3).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4476593&req=5

pone.0130618.g008: Deletion of IFT80 in chondrocytes caused impaired Hh signaling, and enhanced Wnt signaling activity.Primary chondrocytes were derived from P10 IFT80f/f and Col2α1; IFT80f/f mice, which were administered tamoxifen at P4-7. (A) Reporter assay showing Gli responsive luciferase (8×Gli-Luc) activity. Shh (1 μg/mL) treatment resulted in significant increases in luciferase activity in IFT80f/f chondrocytes, whereas less stimulation with Shh was observed in the Col2α1; IFT80f/f chondrocytes (n = 3). (B) Wnt luciferase reporter assay with or without Wnt3a stimulation. 100 ng/mL Wnt3a significantly promoted higher luciferase activity in Col2α1; IFT80f/f chondrocytes compared to IFT80f/f chondrocytes (n = 3).
Mentions: To gain further insight into the molecular mechanisms, we characterized the activation of Hh and Wnt signaling pathways, which are regulated by cilia or cilia related proteins [36, 37]. By performing a reporter assay using a p8×Gli-Luc construct [33], we found that stimulation with Shh resulted in a 3-fold increase in the Gli-responsive luciferase activity in IFT80f/f chondrocytes (Fig 8A). However, this activity significantly decreased in Col2α1; IFT80f/f chondrocytes (Fig 8A), indicating that Hh signaling activity is impaired. We also studied the role of IFT80 in Wnt signaling by performing a reporter assay with the M50 Super 8×TOPFlash construct. Wnt3a led to about 1.5-fold increase in luciferase activity in IFT80f/f chondrocytes, but almost 3-fold increase was found in Col2α1; IFT80f/f chondrocytes (Fig 8B), suggesting that loss of IFT80 promotes Wnt signaling pathway transduction.

Bottom Line: Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development.Loss of IFT80 in the embryonic stage resulted in short limbs at birth.These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Biology, School of Dental Medicine, University of Buffalo, State University of New York, Buffalo, NY, United States of America.

ABSTRACT
Intraflagellar transport proteins (IFT) play important roles in cilia formation and organ development. Partial loss of IFT80 function leads Jeune asphyxiating thoracic dystrophy (JATD) or short-rib polydactyly (SRP) syndrome type III, displaying narrow thoracic cavity and multiple cartilage anomalies. However, it is unknown how IFT80 regulates cartilage formation. To define the role and mechanism of IFT80 in chondrocyte function and cartilage formation, we generated a Col2α1; IFT80f/f mouse model by crossing IFT80f/f mice with inducible Col2α1-CreER mice, and deleted IFT80 in chondrocyte lineage by injection of tamoxifen into the mice in embryonic or postnatal stage. Loss of IFT80 in the embryonic stage resulted in short limbs at birth. Histological studies showed that IFT80-deficient mice have shortened cartilage with marked changes in cellular morphology and organization in the resting, proliferative, pre-hypertrophic, and hypertrophic zones. Moreover, deletion of IFT80 in the postnatal stage led to mouse stunted growth with shortened growth plate but thickened articular cartilage. Defects of ciliogenesis were found in the cartilage of IFT80-deficient mice and primary IFT80-deficient chondrocytes. Further study showed that chondrogenic differentiation was significantly inhibited in IFT80-deficient mice due to reduced hedgehog (Hh) signaling and increased Wnt signaling activities. These findings demonstrate that loss of IFT80 blocks chondrocyte differentiation by disruption of ciliogenesis and alteration of Hh and Wnt signaling transduction, which in turn alters epiphyseal and articular cartilage formation.

No MeSH data available.


Related in: MedlinePlus