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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

Histological examination of the tibial growth plates of newborn IFT80f/f mice and Col2α1; IFT80f/f mice.(A and A’) Histological examination of tibial growth plates of newborn IFT80f/f mice (A) and Col2α1; IFT80f/f mice (A’) by H&E staining. Mice were exposed to tamoxifen at E14.5, E16.5, and E18.5. The growth plate can be divided transversely into resting zone (RZ), proliferation zone (PZ), prehypertrophic zone, (PHZ) and hypertrophic zone (HZ). (B and B’) Safranin O staining of tibial growth plates of newborn IFT80f/f mice (B) and Col2α1; IFT80f/f mice (B’). (C-F and C’-F’) Histological examination of chondrocytes morphology in higher magnification view. Chondrocytes in the resting zone of Col2α1; IFT80f/f mice (C’) displayed hypercellularity compared to those in IFT80f/f mice (C). Cells were less organized in the proliferation zone of Col2α1; IFT80f/f mice (D’) compared to those in IFT80f/f mice (D). In the prehypertrophic and hypertrophic zones, chondrocytes were larger, with less cell density, in Col2α1; IFT80f/f mice (E’ and F’) than those in IFT80f/f mice (E and F). (G) Quantitative analysis of cartilage length (n = 3). (H) Quantitative analysis of each zone’s lengths. Data was reported as a ratio of the zone length to the total growth plate length (n = 3).
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pone.0130618.g002: Histological examination of the tibial growth plates of newborn IFT80f/f mice and Col2α1; IFT80f/f mice.(A and A’) Histological examination of tibial growth plates of newborn IFT80f/f mice (A) and Col2α1; IFT80f/f mice (A’) by H&E staining. Mice were exposed to tamoxifen at E14.5, E16.5, and E18.5. The growth plate can be divided transversely into resting zone (RZ), proliferation zone (PZ), prehypertrophic zone, (PHZ) and hypertrophic zone (HZ). (B and B’) Safranin O staining of tibial growth plates of newborn IFT80f/f mice (B) and Col2α1; IFT80f/f mice (B’). (C-F and C’-F’) Histological examination of chondrocytes morphology in higher magnification view. Chondrocytes in the resting zone of Col2α1; IFT80f/f mice (C’) displayed hypercellularity compared to those in IFT80f/f mice (C). Cells were less organized in the proliferation zone of Col2α1; IFT80f/f mice (D’) compared to those in IFT80f/f mice (D). In the prehypertrophic and hypertrophic zones, chondrocytes were larger, with less cell density, in Col2α1; IFT80f/f mice (E’ and F’) than those in IFT80f/f mice (E and F). (G) Quantitative analysis of cartilage length (n = 3). (H) Quantitative analysis of each zone’s lengths. Data was reported as a ratio of the zone length to the total growth plate length (n = 3).

Mentions: To further investigate the structure of the cartilage, histological examination was performed on the tibias from IFT80f/f mice and Col2α1; IFT80f/f mice. Chondrocytes displayed different morphology within different zones, which including resting, proliferation, prehypertrophic, and hypertrophic zones in epiphyseal plate (Fig 2A). Col2α1; IFT80f/f mice showed disorganized cartilage (Fig 2A’). Safranin O staining further confirmed the abnormal cartilage structure in Col2α1; IFT80f/f mice and showed the reduced proteoglycans production in Col2α1; IFT80f/f mice (Fig 2B and 2B’). Cartilages from IFT80f/f group displayed the typical and clear demarcation of layers with distinct cellular morphology (Fig 2C–2F). The chondrocytes were small and round- or oval-shaped in the resting zone (Fig 2C). However, the resting chondrocytes in Col2α1; IFT80f/f displayed hypercellularity compared to those in IFT80f/f mice (Fig 2C’). In the proliferation zone of IFT80f/f mice, the chondrocytes were flattened and organized into linear clusters parallel to the long bone, representing cells that have recently divided (Fig 2D). However, the proliferation zone was less organized and some of the cells were distributed singularly in Col2α1; IFT80f/f mice (Fig 2D’). Additionally, in IFT80f/f mice, the cells in the prehypertrophic and hypertrophic zones were large and vacuolated (Fig 2E and 2F), and the clear areas of cytoplasm indicate the lipid droplets and glycogen stores. But in the prehypertrophic zone and hypertrophic zones of Col2α1; IFT80f/f group, chondrocytes were larger but had smaller nuclei; moreover, the cell density was also reduced (Fig 2E’ and 2F’) compared to that in IFT80f/f mice (Fig 2E and 2F).


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

Yuan X, Yang S - PLoS ONE (2015)

Histological examination of the tibial growth plates of newborn IFT80f/f mice and Col2α1; IFT80f/f mice.(A and A’) Histological examination of tibial growth plates of newborn IFT80f/f mice (A) and Col2α1; IFT80f/f mice (A’) by H&E staining. Mice were exposed to tamoxifen at E14.5, E16.5, and E18.5. The growth plate can be divided transversely into resting zone (RZ), proliferation zone (PZ), prehypertrophic zone, (PHZ) and hypertrophic zone (HZ). (B and B’) Safranin O staining of tibial growth plates of newborn IFT80f/f mice (B) and Col2α1; IFT80f/f mice (B’). (C-F and C’-F’) Histological examination of chondrocytes morphology in higher magnification view. Chondrocytes in the resting zone of Col2α1; IFT80f/f mice (C’) displayed hypercellularity compared to those in IFT80f/f mice (C). Cells were less organized in the proliferation zone of Col2α1; IFT80f/f mice (D’) compared to those in IFT80f/f mice (D). In the prehypertrophic and hypertrophic zones, chondrocytes were larger, with less cell density, in Col2α1; IFT80f/f mice (E’ and F’) than those in IFT80f/f mice (E and F). (G) Quantitative analysis of cartilage length (n = 3). (H) Quantitative analysis of each zone’s lengths. Data was reported as a ratio of the zone length to the total growth plate length (n = 3).
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pone.0130618.g002: Histological examination of the tibial growth plates of newborn IFT80f/f mice and Col2α1; IFT80f/f mice.(A and A’) Histological examination of tibial growth plates of newborn IFT80f/f mice (A) and Col2α1; IFT80f/f mice (A’) by H&E staining. Mice were exposed to tamoxifen at E14.5, E16.5, and E18.5. The growth plate can be divided transversely into resting zone (RZ), proliferation zone (PZ), prehypertrophic zone, (PHZ) and hypertrophic zone (HZ). (B and B’) Safranin O staining of tibial growth plates of newborn IFT80f/f mice (B) and Col2α1; IFT80f/f mice (B’). (C-F and C’-F’) Histological examination of chondrocytes morphology in higher magnification view. Chondrocytes in the resting zone of Col2α1; IFT80f/f mice (C’) displayed hypercellularity compared to those in IFT80f/f mice (C). Cells were less organized in the proliferation zone of Col2α1; IFT80f/f mice (D’) compared to those in IFT80f/f mice (D). In the prehypertrophic and hypertrophic zones, chondrocytes were larger, with less cell density, in Col2α1; IFT80f/f mice (E’ and F’) than those in IFT80f/f mice (E and F). (G) Quantitative analysis of cartilage length (n = 3). (H) Quantitative analysis of each zone’s lengths. Data was reported as a ratio of the zone length to the total growth plate length (n = 3).
Mentions: To further investigate the structure of the cartilage, histological examination was performed on the tibias from IFT80f/f mice and Col2α1; IFT80f/f mice. Chondrocytes displayed different morphology within different zones, which including resting, proliferation, prehypertrophic, and hypertrophic zones in epiphyseal plate (Fig 2A). Col2α1; IFT80f/f mice showed disorganized cartilage (Fig 2A’). Safranin O staining further confirmed the abnormal cartilage structure in Col2α1; IFT80f/f mice and showed the reduced proteoglycans production in Col2α1; IFT80f/f mice (Fig 2B and 2B’). Cartilages from IFT80f/f group displayed the typical and clear demarcation of layers with distinct cellular morphology (Fig 2C–2F). The chondrocytes were small and round- or oval-shaped in the resting zone (Fig 2C). However, the resting chondrocytes in Col2α1; IFT80f/f displayed hypercellularity compared to those in IFT80f/f mice (Fig 2C’). In the proliferation zone of IFT80f/f mice, the chondrocytes were flattened and organized into linear clusters parallel to the long bone, representing cells that have recently divided (Fig 2D). However, the proliferation zone was less organized and some of the cells were distributed singularly in Col2α1; IFT80f/f mice (Fig 2D’). Additionally, in IFT80f/f mice, the cells in the prehypertrophic and hypertrophic zones were large and vacuolated (Fig 2E and 2F), and the clear areas of cytoplasm indicate the lipid droplets and glycogen stores. But in the prehypertrophic zone and hypertrophic zones of Col2α1; IFT80f/f group, chondrocytes were larger but had smaller nuclei; moreover, the cell density was also reduced (Fig 2E’ and 2F’) compared to that in IFT80f/f mice (Fig 2E and 2F).

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