Nuclear Factor-κB p65 Facilitates Longitudinal Bone Growth by Inducing Growth Plate Chondrocyte Proliferation and Differentiation and by Preventing Apoptosis

NF-κB is a group of transcription factors involved in cell proliferation, differentiation, and apoptosis. Mice deficient in the NF-κB subunits p50 and p52 have retarded growth, suggesting that NF-κB is involved in bone growth. Yet, it is not clear whether the reduced bone growth of these mice depends on the lack of NF-κB activity in growth plate chondrocytes. Using cultured rat metatarsal bones and isolated growth plate chondrocytes, we studied the effects of two NF-κB inhibitors (pyrrolidine dithiocarbamate (PDTC) or BAY11-7082 (BAY)), p65 short interference RNA (siRNA), and of the overexpression of p65 on chondrocyte proliferation, differentiation, and apoptosis. To further define the underlying mechanisms, we studied the functional interaction between NF-κB p65 and BMP-2 in chondrocytes. PDTC and BAY suppressed metatarsal linear growth. Such growth inhibition resulted from decreased chondrocyte proliferation and differentiation and from increased chondrocyte apoptosis. In cultured chondrocytes, the inhibition of NF-κB p65 activation (by PDTC and BAY) and expression (by p65 siRNA) led to the same findings observed in cultured metatarsal bones. In contrast, overexpression of p65 in cultured chondrocytes induced chondrocyte proliferation and differentiation and prevented apoptosis. Although PDTC, BAY, and p65 siRNA reduced the expression of BMP-2 in cultured growth plate chondrocytes, the overexpression of p65 increased it. The addition of Noggin, a BMP-2 antagonist, neutralized the stimulatory effects of p65 on chondrocyte proliferation and differentiation, as well as its anti-apoptotic effect. In conclusion, our findings indicate that NF-κB p65 expressed in growth plate chondrocytes facilitates growth plate chondrogenesis and longitudinal bone growth by inducing BMP-2 expression and activity.

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DHEA Suppresses Longitudinal Bone Growth by Acting Directly at Growth Plate through Estrogen Receptors

Endocrinology ◽

10.1210/en.2010-0920 ◽

2011 ◽

Vol 152 (4) ◽

pp. 1423-1433 ◽

Cited By ~ 8

Author(s):

Hongzhi Sun ◽

Weijin Zang ◽

Bo Zhou ◽

Lin Xu ◽

Shufang Wu

Keyword(s):

Estrogen Receptor ◽

Growth Plate ◽

Bone Growth ◽

Nuclear Factor Κb ◽

Binding Activity ◽

Skeletal Maturation ◽

Chondrocyte Apoptosis ◽

Chondrocyte Proliferation ◽

Longitudinal Bone Growth ◽

Growth Plate Chondrocyte

Abstract Dehydroepiandrosterone (DHEA) is produced by the adrenal cortex and is the most abundant steroid in humans. Although in some physiological and pathological conditions the increased secretion of DHEA and its sulfated form is associated with accelerated growth rate and skeletal maturation, it is unclear whether DHEA can affect longitudinal bone growth and skeletal maturation by acting directly at the growth plate. In our study, DHEA suppressed metatarsal growth, growth plate chondrocyte proliferation, and hypertrophy/differentiation. In addition, DHEA increased the number of apoptotic chondrocytes in the growth plate. In cultured chondrocytes, DHEA reduced chondrocyte proliferation and induced apoptosis. The DHEA-induced inhibition of metatarsal growth and growth plate chondrocyte proliferation and hypertrophy/differentiation was nullified by culturing metatarsals with DHEA in the presence of ICI 182,780, an inhibitor of estrogen receptor, but not in the presence of Casodex, an inhibitor of androgen receptor. Lastly, nuclear factor-κB DNA binding activity was inhibited by the addition of DHEA in the medium of cultured chondrocyte. Our findings indicate that DHEA suppressed bone growth by acting directly at growth plate through estrogen receptor. Such growth inhibition is mediated by decreased chondrocyte proliferation and hypertrophy/differentiation and by increased chondrocyte apoptosis.

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Withdrawal: Nuclear factor-κB p65 facilitates longitudinal bone growth by inducing growth plate chondrocyte proliferation and differentiation and by preventing apoptosis.

Journal of Biological Chemistry ◽

10.1074/jbc.w120.015606 ◽

2020 ◽

Vol 295 (39) ◽

pp. 13691-13691

Author(s):

Shufang Wu ◽

Janna K. Flint ◽

Geoffrey Rezvani ◽

Francesco De Luca

Keyword(s):

Growth Plate ◽

Bone Growth ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Chondrocyte Proliferation ◽

Longitudinal Bone Growth ◽

Growth Plate Chondrocyte ◽

Proliferation And Differentiation

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Fluoride Inhibits Longitudinal Bone Growth by Acting Directly at the Growth Plate in Cultured Neonatal Rat Metatarsal Bones

Biological Trace Element Research ◽

10.1007/s12011-019-01997-9 ◽

2019 ◽

Vol 197 (2) ◽

pp. 522-532 ◽

Cited By ~ 1

Author(s):

Rui Ma ◽

Shuang Liu ◽

Tingting Qiao ◽

Demin Li ◽

Ruixue Zhang ◽

...

Keyword(s):

Growth Plate ◽

Bone Growth ◽

Neonatal Rat ◽

Longitudinal Bone Growth ◽

Metatarsal Bones

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Mechanism of longitudinal bone growth and its regulation by growth plate chondrocytes

Microscopy Research and Technique ◽

10.1002/jemt.1070280606 ◽

1994 ◽

Vol 28 (6) ◽

pp. 505-519 ◽

Cited By ~ 289

Author(s):

Ernst B. Hunziker

Keyword(s):

Growth Plate ◽

Bone Growth ◽

Growth Plate Chondrocytes ◽

Longitudinal Bone Growth

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Chemotherapeutic agents used in the treatment of childhood malignancies have direct effects on growth plate chondrocyte proliferation

Journal of Endocrinology ◽

10.1677/joe.0.1570225 ◽

1998 ◽

Vol 157 (2) ◽

pp. 225-235 ◽

Cited By ~ 42

Author(s):

H Robson ◽

E Anderson ◽

OB Eden ◽

O Isaksson ◽

S Shalet

Keyword(s):

Suspension Culture ◽

Growth Plate ◽

Bone Growth ◽

Chemotherapeutic Agents ◽

Long Bone ◽

Direct Effects ◽

Growth Plate Chondrocytes ◽

Chondrocyte Proliferation ◽

Childhood Malignancies ◽

The Impact

Short stature is one of the most well recorded long term sequelae for adult survivors of childhood malignancies. It has become increasingly apparent that cytotoxic chemotherapy, as well as craniospinal irradiation, has a major impact on growth, but there are virtually no studies which explore the mechanisms by which these cytotoxic drugs affect growth. We have used an in vitro system to investigate the direct effects of a range of chemotherapeutic agents on the proliferative responses of rat tibial growth plate chondrocytes, both in suspension and monolayer culture. The glucocorticoids and purine anti-metabolites reduced chondrocyte proliferation both in monolayer and suspension cultures and this resulted from an increase in cell doubling times with a concomittant reduction in the numbers of S phase cells. DNA damaging agents (e.g. actinomycin-D) were also able to reduce chondrocyte proliferation, both in monolayer and suspension culture. This, however, was the result of a cell cycle arrest and subsequent cell death. In our studies, methotrexate had no significant effect on the proliferative responses of the chondrocytes either in monolayer or suspension culture. These results indicate direct effects of a range of chemotherapeutic agents on the proliferative responses of growth plate chondrocytes. Both cytostatic and cytotoxic effects were observed although the impact of either the potential loss of cells from the proliferative pool during chondrocyte differentiation, or the reduction in the rate of chondrocyte turnover on long bone growth remains to be elucidated.

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Locally produced estrogen promotes fetal rat metatarsal bone growth; an effect mediated through increased chondrocyte proliferation and decreased apoptosis

Journal of Endocrinology ◽

10.1677/joe.1.06364 ◽

2006 ◽

Vol 188 (2) ◽

pp. 193-203 ◽

Cited By ~ 46

Author(s):

A S Chagin ◽

D Chrysis ◽

M Takigawa ◽

E M Ritzen ◽

L Sävendahl

Keyword(s):

Growth Plate ◽

Bone Growth ◽

Longitudinal Growth ◽

Epiphyseal Growth Plate ◽

Chondrocyte Proliferation ◽

Growth Plate Cartilage ◽

Ici 182,780 ◽

Metatarsal Bones ◽

Fetal Rat ◽

Estrogen Synthesis

The importance of estrogens for the regulation of longitudinal bone growth is unequivocal. However, any local effect of estrogens in growth plate cartilage has been debated. Recently, several enzymes essential for estrogen synthesis were shown to be expressed in rat growth plate chondrocytes. Local production of 17β-estradiol (E2) has also been demonstrated in rat costal chondrocytes. We aimed to determine the functional role of locally produced estrogen in growth plate cartilage. The human chondrocyte-like cell line HCS-2/8 was used to study estrogen effects on cell proliferation (3H-labeled thymidine uptake) and apoptosis (cell death detection ELISA kit). Chondrocyte production of E2 was measured by RIA and organ cultures of fetal rat metatarsal bones were used to study the effects of estrogen on longitudinal growth rate. We found that significant amounts of E2 were produced by HCS-2/8 chondrocytes (64.1 ± 5.3 fmol/3 days/106cells). The aromatase inhibitor letrozole (1 μM) and the pure estrogen receptor antagonist ICI 182,780 (10 μM) inhibited proliferation of HCS-2/8 chondrocytes by 20% (P<0.01) and almost 50% (P<0.001), respectively. Treatment with ICI 182,780 (10 μM) increased apoptosis by 228% (P<0.05). Co-treatment with either caspase-3 or pan-caspase inhibitors completely blocked ICI 182,780-induced apoptosis (P<0.001 vs ICI 182,780 only). Moreover, both ICI 182,780 (10 μM) and letrozole (1 μM) decreased longitudinal growth of fetal rat metatarsal bones after 7 days of culture (P<0.01). In conclusion, our data clearly show that chondrocytes endogenously produce E2 and that locally produced estrogen stimulates chondrocyte proliferation and protects from spontaneous apoptosis. In addition, longitudinal growth is promoted by estrogens locally produced within the epiphyseal growth plate.

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The role of estrogen receptor-α and its activation function-1 for growth plate closure in female mice

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00646.2011 ◽

2012 ◽

Vol 302 (11) ◽

pp. E1381-E1389 ◽

Cited By ~ 26

Author(s):

A. E. Börjesson ◽

S. H. Windahl ◽

E. Karimian ◽

E. E. Eriksson ◽

M. K. Lagerquist ◽

...

Keyword(s):

Estrogen Receptor ◽

Growth Plate ◽

Bone Growth ◽

High Dose ◽

Plate Height ◽

Chondrocyte Proliferation ◽

Growth Plates ◽

Longitudinal Bone Growth ◽

Female Mice

High estradiol levels in late puberty induce growth plate closure and thereby cessation of growth in humans. In mice, the growth plates do not fuse after sexual maturation, but old mice display reduced longitudinal bone growth and high-dose estradiol treatment induces growth plate closure. Estrogen receptor (ER)-α stimulates gene transcription via two activation functions (AFs), AF-1 and AF-2. To evaluate the role of ERα and its AF-1 for age-dependent reduction in longitudinal bone growth and growth plate closure, female mice with inactivation of ERα (ERα−/−) or ERαAF-1 (ERαAF-10) were evaluated. Old (16- to 19-mo-old) female ERα−/− mice showed continued substantial longitudinal bone growth, resulting in longer bones (tibia: +8.3%, P < 0.01) associated with increased growth plate height (+18%, P < 0.05) compared with wild-type (WT) mice. In contrast, the longitudinal bone growth ceased in old ERαAF-10 mice (tibia: −4.9%, P < 0.01). Importantly, the proximal tibial growth plates were closed in all old ERαAF-10 mice while they were open in all WT mice. Growth plate closure was associated with a significantly altered balance between chondrocyte proliferation and apoptosis in the growth plate. In conclusion, old female ERα−/− mice display a prolonged and enhanced longitudinal bone growth associated with increased growth plate height, resembling the growth phenotype of patients with inactivating mutations in ERα or aromatase. In contrast, ERαAF-1 deletion results in a hyperactive ERα, altering the chondrocyte proliferation/apoptosis balance, leading to growth plate closure. This suggests that growth plate closure is induced by functions of ERα that do not require AF-1 and that ERαAF-1 opposes growth plate closure.

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Resveratrol reduces COMPopathy in mice through activation of autophagy

10.1101/2020.10.26.355628 ◽

2020 ◽

Author(s):

Jacqueline T. Hecht ◽

Francoise Coustry ◽

Alka C. Veerisetty ◽

Mohammad G. Hossain ◽

Karen L. Posey

Keyword(s):

Growth Plate ◽

Matrix Protein ◽

Mammalian Target Of Rapamycin ◽

Growth Plate Chondrocytes ◽

Chondrocyte Proliferation ◽

Chondrocyte Death ◽

Mtorc1 Signaling ◽

And Oxidative Stress ◽

Cultured Chondrocytes

AbstractMisfolding mutations in cartilage oligomeric matrix protein (COMP) cause it to be retained within in ER of chondrocytes, stimulating a multitude of damaging cellular responses including ER stress, inflammation and oxidative stress which ultimately culminates in the death of growth plate chondrocytes and pseudoachondroplasia (PSACH). Previously, we demonstrated that an antioxidant, resveratrol, substantially reduces the intracellular accumulation of mutant COMP, dampens cellular stress and lowers the level of growth plate chondrocyte death. In addition, we showed that resveratrol reduces mTORC1 (mammalian target of rapamycin complex 1) signaling, suggesting a potential mechanism. In this work, we investigate the role of autophagy in treatment of COMPopathies. In cultured chondrocytes expressing wild type or mutant COMP (MT-COMP), resveratrol significantly increased the number of large LC3 vesicles, directly demonstrating that resveratrol stimulated autophagy is an important component of the resveratrol-driven mechanism responsible for the degradation of mutant COMP. Moreover, pharmacological inhibitors of autophagy suppressed degradation of MT-COMP in our established mouse model of PSACH. In contrast, blockage of the proteasome did not substantially alter resveratrol clearance of mutant COMP from growth plate chondrocytes. Mechanistically, resveratrol increased SIRT1 and PP2A expression and reduced MID1 expression and activation of pAKT and mTORC1 signaling in growth plate chondrocytes, allowing clearance of mutant COMP by autophagy. Importantly, we show that optimal reduction in growth plate pathology, including decreased mutant COMP retention, decreased mTORC1 signaling and restoration of chondrocyte proliferation was attained when treatment was initiated between birth to one week of age in MT-COMP mice, translating to birth to approximately 2 years of age in PSACH children. These results clearly demonstrate that resveratrol stimulates clearance of mutant COMP by an autophagy-centric mechanism.

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STAT1 mediates the increased apoptosis and reduced chondrocyte proliferation in mice overexpressing FGF2

Development ◽

10.1242/dev.128.11.2119 ◽

2001 ◽

Vol 128 (11) ◽

pp. 2119-2129 ◽

Cited By ~ 4

Author(s):

Malika Sahni ◽

Regina Raz ◽

J. Douglas Coffin ◽

David Levy ◽

Claudio Basilico

Keyword(s):

Growth Plate ◽

Bone Growth ◽

Fgf Signaling ◽

Intramembranous Ossification ◽

Epiphyseal Growth Plate ◽

Growth Plate Chondrocytes ◽

Chondrocyte Proliferation ◽

Transgenic Mouse Line ◽

Proliferative Zone ◽

Significant Correction

Unregulated FGF receptor signaling results in bone malformations that affect both endochondral and intramembranous ossification, and is the basis for several genetic forms of human dwarfism. FGF signaling inhibits chondrocyte proliferation and we have previously shown that the transcription factor STAT1 mediates the growth inhibitory effect of FGF in vitro. We provide genetic evidence that STAT1 is a modulator of the negative regulation of bone growth by FGF in vivo. We crossed Stat1−/− mice with a transgenic mouse line overexpressing human FGF2 (TgFGF). TgFGF mice exhibit phenotypes characterized by chondrodysplasia and macrocephaly, which affect endochondral and intramembranous ossification. We found that the chondrodysplasic phenotype of these mice results both from reduced proliferation and increased apoptosis of growth plate chondrocytes. Loss of STAT1 function in TgFGF mice led to a significant correction of the chondrodysplasic phenotype, but did not affect the skull malformations. The reduced proliferation of TgFGF growth plate chondrocytes, as well as their excessive apoptosis, were restored to near-normal levels in the absence of STAT1 function. Unregulated FGF signaling in TgFGF mice also induced apoptosis in calvarial osteoblasts that was not, however, corrected by the absence of STAT1. Detailed analysis of Stat1−/− growth plates uncovered a transient phenotype, characterized by an expansion of the proliferative zone and by acceleration of longitudinal bone growth, that attenuated as the animals grew older. These results document an essential role for STAT1 in FGF-mediated regulation of cell growth that is specific to the epiphyseal growth plate.

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