The Regulation of Runt-related Transcription Factor 2 by Fibroblast Growth Factor-2 and Connexin43 Requires the Inositol Polyphosphate/protein Kinase Cδ Cascade

Overview

Journal J Bone Miner Res

Publisher Oxford University Press

Date 2013 Jan 17

PMID 23322705

Citations 34

Authors

Corinne Niger

Maria A Luciotti

Atum M Buo

Carla Hebert

Vy Ma

Joseph P Stains

Affiliations

Soon will be listed here.

Abstract

Connexin43 (Cx43) plays a critical role in osteoblast function and bone mass accrual, yet the identity of the second messengers communicated by Cx43 gap junctions, the targets of these second messengers and how they regulate osteoblast function remain largely unknown. We have shown that alterations of Cx43 expression in osteoblasts can impact the responsiveness to fibroblast growth factor-2 (FGF2), by modulating the transcriptional activity of runt-related transcription factor 2 (Runx2). In this study, we examined the contribution of the phospholipase Cγ1/inositol polyphosphate/protein kinase C delta (PKCδ) cascade to the Cx43-dependent transcriptional response of MC3T3 osteoblasts to FGF2. Knockdown of expression and/or inhibition of function of phospholipase Cγ1, inositol polyphosphate multikinase, which generates inositol 1,3,4,5-tetrakisphosphate (InsP₄) and InsP₅, and inositol hexakisphosphate kinase 1/2, which generates inositol pyrophosphates, prevented the ability of Cx43 to potentiate FGF2-induced signaling through Runx2. Conversely, overexpression of phospholipase Cγ1 and inositol hexakisphosphate kinase 1/2 enhanced FGF2 activation of Runx2 and the effect of Cx43 overexpression on this response. Disruption of these pathways blocked the nuclear accumulation of PKCδ and the FGF2-dependent interaction of PKCδ and Runx2, reducing Runx2 transcriptional activity. These data reveal that FGF2-signaling involves the inositol polyphosphate cascade, including inositol hexakisphosphate kinase (IP6K), and demonstrate that IP6K regulates Runx2 and osteoblast gene expression. Additionally, these data implicate the water-soluble inositol polyphosphates as mediators of the Cx43-dependent amplification of the osteoblast response to FGF2, and suggest that these low molecular weight second messengers may be biologically relevant mediators of osteoblast function that are communicated by Cx43-gap junctions.

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References

Ducy P, Karsenty G . Two distinct osteoblast-specific cis-acting elements control expression of a mouse osteocalcin gene. Mol Cell Biol. 1995; 15(4):1858-69. PMC: 230411. DOI: 10.1128/MCB.15.4.1858. View

Bivi N, Condon K, Allen M, Farlow N, Passeri G, Brun L . Cell autonomous requirement of connexin 43 for osteocyte survival: consequences for endocortical resorption and periosteal bone formation. J Bone Miner Res. 2011; 27(2):374-89. PMC: 3271138. DOI: 10.1002/jbmr.548. View

Niger C, Howell F, Stains J . Interleukin-1beta increases gap junctional communication among synovial fibroblasts via the extracellular-signal-regulated kinase pathway. Biol Cell. 2009; 102(1):37-49. PMC: 2874634. DOI: 10.1042/BC20090056. View

Bivi N, Lezcano V, Romanello M, Bellido T, Plotkin L . Connexin43 interacts with βarrestin: a pre-requisite for osteoblast survival induced by parathyroid hormone. J Cell Biochem. 2011; 112(10):2920-30. PMC: 3178733. DOI: 10.1002/jcb.23208. View

Li Z, Zhou Z, Yellowley C, Donahue H . Inhibiting gap junctional intercellular communication alters expression of differentiation markers in osteoblastic cells. Bone. 1999; 25(6):661-6. DOI: 10.1016/s8756-3282(99)00227-6. View

Willis D, Loewy A, Charlton-Kachigian N, Shao J, Ornitz D, Towler D . Regulation of osteocalcin gene expression by a novel Ku antigen transcription factor complex. J Biol Chem. 2002; 277(40):37280-91. DOI: 10.1074/jbc.M206482200. View

Elfgang C, Eckert R, Lichtenberg-Frate H, Butterweck A, Traub O, Klein R . Specific permeability and selective formation of gap junction channels in connexin-transfected HeLa cells. J Cell Biol. 1995; 129(3):805-17. PMC: 2120441. DOI: 10.1083/jcb.129.3.805. View

Chakraborty A, Koldobskiy M, Sixt K, Juluri K, Mustafa A, Snowman A . HSP90 regulates cell survival via inositol hexakisphosphate kinase-2. Proc Natl Acad Sci U S A. 2008; 105(4):1134-9. PMC: 2234104. DOI: 10.1073/pnas.0711168105. View

Stains J, Lecanda F, Screen J, Towler D, Civitelli R . Gap junctional communication modulates gene transcription by altering the recruitment of Sp1 and Sp3 to connexin-response elements in osteoblast promoters. J Biol Chem. 2003; 278(27):24377-87. DOI: 10.1074/jbc.M212554200. View

10.

Flenniken A, Osborne L, Anderson N, Ciliberti N, Fleming C, Gittens J . A Gja1 missense mutation in a mouse model of oculodentodigital dysplasia. Development. 2005; 132(19):4375-86. DOI: 10.1242/dev.02011. View

11.

Kim B, Kim H, Park H, Kim Y, Yoon W, Lee S . Runx2 phosphorylation induced by fibroblast growth factor-2/protein kinase C pathways. Proteomics. 2006; 6(4):1166-74. DOI: 10.1002/pmic.200500289. View

12.

Grimston S, Brodt M, Silva M, Civitelli R . Attenuated response to in vivo mechanical loading in mice with conditional osteoblast ablation of the connexin43 gene (Gja1). J Bone Miner Res. 2008; 23(6):879-86. PMC: 2677086. DOI: 10.1359/jbmr.080222. View

13.

Chakraborty A, Kim S, Snyder S . Inositol pyrophosphates as mammalian cell signals. Sci Signal. 2011; 4(188):re1. PMC: 3667551. DOI: 10.1126/scisignal.2001958. View

14.

Tsui M, York J . Roles of inositol phosphates and inositol pyrophosphates in development, cell signaling and nuclear processes. Adv Enzyme Regul. 2009; 50(1):324-37. PMC: 3269838. DOI: 10.1016/j.advenzreg.2009.12.002. View

15.

Stains J, Civitelli R . Gap junctions regulate extracellular signal-regulated kinase signaling to affect gene transcription. Mol Biol Cell. 2004; 16(1):64-72. PMC: 539152. DOI: 10.1091/mbc.e04-04-0339. View

16.

Sierra O, Cheng S, Loewy A, Charlton-Kachigian N, Towler D . MINT, the Msx2 interacting nuclear matrix target, enhances Runx2-dependent activation of the osteocalcin fibroblast growth factor response element. J Biol Chem. 2004; 279(31):32913-23. DOI: 10.1074/jbc.M314098200. View

17.

Veenstra R . Size and selectivity of gap junction channels formed from different connexins. J Bioenerg Biomembr. 1996; 28(4):327-37. DOI: 10.1007/BF02110109. View

18.

Plotkin L, Lezcano V, Thostenson J, Weinstein R, Manolagas S, Bellido T . Connexin 43 is required for the anti-apoptotic effect of bisphosphonates on osteocytes and osteoblasts in vivo. J Bone Miner Res. 2008; 23(11):1712-21. PMC: 2648607. DOI: 10.1359/jbmr.080617. View

19.

Marie P, Coffin J, Hurley M . FGF and FGFR signaling in chondrodysplasias and craniosynostosis. J Cell Biochem. 2005; 96(5):888-96. DOI: 10.1002/jcb.20582. View

20.

Alcazar-Roman A, Wente S . Inositol polyphosphates: a new frontier for regulating gene expression. Chromosoma. 2007; 117(1):1-13. DOI: 10.1007/s00412-007-0126-4. View