Limits...
KIF7 Controls the Proliferation of Cells of the Respiratory Airway through Distinct Microtubule Dependent Mechanisms.

Coles GL, Baglia LA, Ackerman KG - PLoS Genet. (2015)

Bottom Line: However, whether Kif7 has a function in nonciliated cells remains largely unknown.Immunostaining and transmission electron microscopy experiments show that Kif7dda/dda mutant lungs are hyperproliferative and exhibit reduced alveolar epithelial cell differentiation.We ascertained that in G1, Kif7 and microtubule dynamics regulate the expression and activity of several components of the cell cycle machinery known to control entry into S phase.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America.

ABSTRACT
The cell cycle must be tightly coordinated for proper control of embryonic development and for the long-term maintenance of organs such as the lung. There is emerging evidence that Kinesin family member 7 (Kif7) promotes Hedgehog (Hh) signaling during embryonic development, and its misregulation contributes to diseases such as ciliopathies and cancer. Kif7 encodes a microtubule interacting protein that controls Hh signaling through regulation of microtubule dynamics within the primary cilium. However, whether Kif7 has a function in nonciliated cells remains largely unknown. The role Kif7 plays in basic cell biological processes like cell proliferation or cell cycle progression also remains to be elucidated. Here, we show that Kif7 is required for coordination of the cell cycle, and inactivation of this gene leads to increased cell proliferation in vivo and in vitro. Immunostaining and transmission electron microscopy experiments show that Kif7dda/dda mutant lungs are hyperproliferative and exhibit reduced alveolar epithelial cell differentiation. KIF7 depleted C3H10T1/2 fibroblasts and Kif7dda/dda mutant mouse embryonic fibroblasts have increased growth rates at high cellular densities, suggesting that Kif7 may function as a general regulator of cellular proliferation. We ascertained that in G1, Kif7 and microtubule dynamics regulate the expression and activity of several components of the cell cycle machinery known to control entry into S phase. Our data suggest that Kif7 may function to regulate the maintenance of the respiratory airway architecture by controlling cellular density, cell proliferation, and cycle exit through its role as a microtubule associated protein.

No MeSH data available.


Related in: MedlinePlus

KIF7 is a negative regulator of cell proliferation within the respiratory epithelium.(A.-B’) Transmission electron micrographs of E18.5 control and Kif7dd/dd mutant respiratory airways. RBC (red blood cell) within the capillary adjacent to a type 1 AEC (1), AEC2 (2), Glycogen (G), Surfactant (S), Arrowheads denote lamellar bodies. (C.-C’) Immunofluorescent staining of SFTPC in E18.5 control and Kif7dd/dd mutant lungs. (D.-D’) Co-immunoflorescent staining of Brdu (red) and CDH1 (green) in E17.5 control and Kif7dd/dd mutant lungs. (E.) Quantification of relative number of immunopositive cells in control and Kif7dd/dd mutant tissue sections. Immunopositive cells were counted and then divided by the total number of cells for control and mutant tissue sections. Control values were set as 1, and mutant values were divided by control values to provide a relative frequency of immunopositive cells per tissue section. At least 4 consecutive tissue sections were counted and averaged for an individual, from at least 4 sets of control and Kif7dd/dd mutant lungs. * P<0.05, **P<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4595342&req=5

pgen.1005525.g003: KIF7 is a negative regulator of cell proliferation within the respiratory epithelium.(A.-B’) Transmission electron micrographs of E18.5 control and Kif7dd/dd mutant respiratory airways. RBC (red blood cell) within the capillary adjacent to a type 1 AEC (1), AEC2 (2), Glycogen (G), Surfactant (S), Arrowheads denote lamellar bodies. (C.-C’) Immunofluorescent staining of SFTPC in E18.5 control and Kif7dd/dd mutant lungs. (D.-D’) Co-immunoflorescent staining of Brdu (red) and CDH1 (green) in E17.5 control and Kif7dd/dd mutant lungs. (E.) Quantification of relative number of immunopositive cells in control and Kif7dd/dd mutant tissue sections. Immunopositive cells were counted and then divided by the total number of cells for control and mutant tissue sections. Control values were set as 1, and mutant values were divided by control values to provide a relative frequency of immunopositive cells per tissue section. At least 4 consecutive tissue sections were counted and averaged for an individual, from at least 4 sets of control and Kif7dd/dd mutant lungs. * P<0.05, **P<0.01.

Mentions: Hh/Gli signaling regulates cyclin d expression and overexpression of cyclin d disrupts cell cycle exit and differentiation [25–27]. Since we observed that Kif7 mutant lungs were dense, histologically immature, and had high levels of Ki67, we examined the expression of cyclin d1 in confluent cultures of Kif7 depleted MLFs. We determined that inhibition of Kif7 led to increased expression of cyclin d1, suggesting that the loss of KIF7 may affect cell cycle exit (Fig 2H). As Kif7 has been implicated in regulating microtubule stability [11,16], we also examined the expression of acetylated alpha tubulin (Act TUB) and detyrosinated alpha tubulin (Dtyr TUB) (2 markers of stable or long-lived microtubules). We observed that postconfluent cultures of Kif7 depleted MLFs contained higher levels of acetylated alpha tubulin and detyrosinated alpha tubulin (Fig 3H), indicating that KIF7 may negatively regulate microtubule stability in mouse lung fibroblasts.


KIF7 Controls the Proliferation of Cells of the Respiratory Airway through Distinct Microtubule Dependent Mechanisms.

Coles GL, Baglia LA, Ackerman KG - PLoS Genet. (2015)

KIF7 is a negative regulator of cell proliferation within the respiratory epithelium.(A.-B’) Transmission electron micrographs of E18.5 control and Kif7dd/dd mutant respiratory airways. RBC (red blood cell) within the capillary adjacent to a type 1 AEC (1), AEC2 (2), Glycogen (G), Surfactant (S), Arrowheads denote lamellar bodies. (C.-C’) Immunofluorescent staining of SFTPC in E18.5 control and Kif7dd/dd mutant lungs. (D.-D’) Co-immunoflorescent staining of Brdu (red) and CDH1 (green) in E17.5 control and Kif7dd/dd mutant lungs. (E.) Quantification of relative number of immunopositive cells in control and Kif7dd/dd mutant tissue sections. Immunopositive cells were counted and then divided by the total number of cells for control and mutant tissue sections. Control values were set as 1, and mutant values were divided by control values to provide a relative frequency of immunopositive cells per tissue section. At least 4 consecutive tissue sections were counted and averaged for an individual, from at least 4 sets of control and Kif7dd/dd mutant lungs. * P<0.05, **P<0.01.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595342&req=5

pgen.1005525.g003: KIF7 is a negative regulator of cell proliferation within the respiratory epithelium.(A.-B’) Transmission electron micrographs of E18.5 control and Kif7dd/dd mutant respiratory airways. RBC (red blood cell) within the capillary adjacent to a type 1 AEC (1), AEC2 (2), Glycogen (G), Surfactant (S), Arrowheads denote lamellar bodies. (C.-C’) Immunofluorescent staining of SFTPC in E18.5 control and Kif7dd/dd mutant lungs. (D.-D’) Co-immunoflorescent staining of Brdu (red) and CDH1 (green) in E17.5 control and Kif7dd/dd mutant lungs. (E.) Quantification of relative number of immunopositive cells in control and Kif7dd/dd mutant tissue sections. Immunopositive cells were counted and then divided by the total number of cells for control and mutant tissue sections. Control values were set as 1, and mutant values were divided by control values to provide a relative frequency of immunopositive cells per tissue section. At least 4 consecutive tissue sections were counted and averaged for an individual, from at least 4 sets of control and Kif7dd/dd mutant lungs. * P<0.05, **P<0.01.
Mentions: Hh/Gli signaling regulates cyclin d expression and overexpression of cyclin d disrupts cell cycle exit and differentiation [25–27]. Since we observed that Kif7 mutant lungs were dense, histologically immature, and had high levels of Ki67, we examined the expression of cyclin d1 in confluent cultures of Kif7 depleted MLFs. We determined that inhibition of Kif7 led to increased expression of cyclin d1, suggesting that the loss of KIF7 may affect cell cycle exit (Fig 2H). As Kif7 has been implicated in regulating microtubule stability [11,16], we also examined the expression of acetylated alpha tubulin (Act TUB) and detyrosinated alpha tubulin (Dtyr TUB) (2 markers of stable or long-lived microtubules). We observed that postconfluent cultures of Kif7 depleted MLFs contained higher levels of acetylated alpha tubulin and detyrosinated alpha tubulin (Fig 3H), indicating that KIF7 may negatively regulate microtubule stability in mouse lung fibroblasts.

Bottom Line: However, whether Kif7 has a function in nonciliated cells remains largely unknown.Immunostaining and transmission electron microscopy experiments show that Kif7dda/dda mutant lungs are hyperproliferative and exhibit reduced alveolar epithelial cell differentiation.We ascertained that in G1, Kif7 and microtubule dynamics regulate the expression and activity of several components of the cell cycle machinery known to control entry into S phase.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America.

ABSTRACT
The cell cycle must be tightly coordinated for proper control of embryonic development and for the long-term maintenance of organs such as the lung. There is emerging evidence that Kinesin family member 7 (Kif7) promotes Hedgehog (Hh) signaling during embryonic development, and its misregulation contributes to diseases such as ciliopathies and cancer. Kif7 encodes a microtubule interacting protein that controls Hh signaling through regulation of microtubule dynamics within the primary cilium. However, whether Kif7 has a function in nonciliated cells remains largely unknown. The role Kif7 plays in basic cell biological processes like cell proliferation or cell cycle progression also remains to be elucidated. Here, we show that Kif7 is required for coordination of the cell cycle, and inactivation of this gene leads to increased cell proliferation in vivo and in vitro. Immunostaining and transmission electron microscopy experiments show that Kif7dda/dda mutant lungs are hyperproliferative and exhibit reduced alveolar epithelial cell differentiation. KIF7 depleted C3H10T1/2 fibroblasts and Kif7dda/dda mutant mouse embryonic fibroblasts have increased growth rates at high cellular densities, suggesting that Kif7 may function as a general regulator of cellular proliferation. We ascertained that in G1, Kif7 and microtubule dynamics regulate the expression and activity of several components of the cell cycle machinery known to control entry into S phase. Our data suggest that Kif7 may function to regulate the maintenance of the respiratory airway architecture by controlling cellular density, cell proliferation, and cycle exit through its role as a microtubule associated protein.

No MeSH data available.


Related in: MedlinePlus