Role of diabetes- and obesity-related protein in the regulation of osteoblast differentiation

Linares, Gabriel; Xing, Weirong; Burghardt, Hans; Baumgartner, Bernhard; Chen, Shin‐Tai; Ricart, Wifredo; Fernández-Real, José Manuel; Zorzano, António; Mohan, Subburaman

doi:10.1152/ajpendo.00065.2011

Cited by 10 publications

(8 citation statements)

References 44 publications

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“…The cells were then treated with βGP ± AA for 72 hrs, before being rinsed with PBS and permeabilized with ALP activity buffer containing 0.1% triton X-100 in 250 mM NaHCO3. Protein concentration was determined by the BCA method (Thermo Fisher Scientific; Waltham, MA) and ALP activity was detected as previously described [27] .…”

Section: Methodsmentioning

confidence: 99%

Differential Expression of Claudin Family Members during Osteoblast and Osteoclast Differentiation: Cldn-1 Is a Novel Positive Regulator of Osteoblastogenesis

Alshbool

Mohan

2014

PLoS ONE

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Claudins (Cldns), a family of 27 transmembrane proteins, represent major components of tight junctions. Aside from functioning as tight junctions, Cldns have emerging roles as regulators of cell proliferation and differentiation. While Cldns are known to be expressed and have important functions in various tissues, their expression and function in bone cells is ill-defined. In this study, the expression of Cldns was examined during osteoblast and osteoclast differentiation. The expression of Cldn-1, -7, -11, and -15 was downregulated during early stages of osteoclast differentiation, whereas Cldn-6 was upregulated. Moreover, the expression of several Cldns increased 3–7 fold in fully differentiated osteoclasts. As for osteoblasts, the expression of several Cldns was found to increase more than 10-fold during differentiation, with some peaking at early, and others at late stages. By contrast, only expression of Cldn-12, and -15 decreased during osteoblast differentiation. In subsequent studies, we focused on the role of Cldn-1 in osteoblasts as its expression was increased by more than 10 fold during osteoblast differentiation and was found to be regulated by multiple osteoregulatory agents including IGF-1 and Wnt3a. We evaluated the consequence of lentiviral shRNA-mediated knockdown of Cldn-1 on osteoblast proliferation and differentiation using MC3T3-E1 mouse osteoblasts. Cldn-1 knockdown caused a significant reduction in MC3T3-E1 cell proliferation and ALP activity. Accordingly, expression levels of cyclinD1 and ALP mRNA levels were reduced in Cldn-1 shRNA knockdown cells. We next determined if Cldn-1 regulates the expression of Runx-2 and osterix, master transcription factors of osteoblast differentiation, and found that their levels were reduced significantly as a consequence of Cldn-1 knockdown. Moreover, knocking down Cldn-1 reduced β-catenin level. In conclusion, the expression of Cldn family members during bone cell differentiation is complex and involves cell type and differentiation stage-dependent regulation. In addition, Cldn-1 is a positive regulator of osteoblast proliferation and differentiation.

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Section: Methodsmentioning

confidence: 99%

Differential Expression of Claudin Family Members during Osteoblast and Osteoclast Differentiation: Cldn-1 Is a Novel Positive Regulator of Osteoblastogenesis

Alshbool

Mohan

2014

PLoS ONE

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“…Nuclear extracts of RAW264.7 cells expressing MLV-Cldn-18, MLV-Cldn-18 ΔPDZ, and MLV-β-Gal were prepared as reported elsewhere (35). Protein concentration was determined by Bradford method and immunoblotting was carried out as described (36). Membranes were probed with antibodies against Cldn-18 (C-term) (1:250) (Invitrogen, Carlsbad, CA), ZO-2 (R-19) (1:250) (Santa Cruz Biotechnology Inc, Santa Cruz, CA), Histone H3 (1:10,000) (Sigma Aldrich, St. Louis, MO), and β-actin (1:10,000) (Sigma Aldrich, St. Louis, MO).…”

Section: Methodsmentioning

confidence: 99%

Claudin 18 is a novel negative regulator of bone resorption and osteoclast differentiation

Linares

Brommage

Powell

et al. 2012

Journal of Bone and Mineral Research

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Claudin 18 (Cldn-18) belongs to a large family of transmembrane proteins that are important components of tight junction strands. Although several claudin members are expressed in bone, the functional role for any claudin member in bone is unknown. Here we demonstrate that disruption of Cldn-18 in mice markedly decreased total body bone mineral density, trabecular bone volume, and cortical thickness in Cldn-18 −/− mice. Histomorphometric studies revealed that bone resorption parameters were increased significantly in Cldn-18 −/− mice without changes in bone formation. Serum levels of TRAP5b and mRNA expression levels of osteoclast specific markers and signaling molecules were also increased. Loss of Cldn-18 further exacerbated calcium deficiency induced bone loss by influencing bone resorption, thereby resulting in mechanically weaker bone. In vitro studies with bone marrow macrophages revealed Cldn-18 disruption markedly enhanced RANKL-induced osteoclast differentiation but not MCSF-induced BMM proliferation. Consistent with a direct role for Cldn-18 in regulating osteoclast differentiation, overexpression of wild type but not PDZ binding motif deleted Cldn-18 inhibited RANKL-induced osteoclast differentiation. Furthermore, our findings indicate that Cldn-18 interacts with Zonula occludens 2 (ZO-2) to modulate RANKL signaling in osteoclasts. In conclusion, we demonstrate that Cldn-18 is a novel negative regulator of bone resorption and osteoclast differentiation.

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“…Recently, we have shown that diabetes-and obesityrelated protein (DOR), a key modulator of TH function in muscle cells, is differentially regulated by TH and acts as a stimulatory mediator of TH effects in osteoblasts (91).…”

Section: Effects Of T3 In Bone Cells In Vitro Chondrocytesmentioning

confidence: 99%

Role and Mechanisms of Actions of Thyroid Hormone on the Skeletal Development

Kim

Mohan

2013

Bone Res.

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The importance of the thyroid hormone axis in the regulation of skeletal growth and maintenance has been well established from clinical studies involving patients with mutations in proteins that regulate synthesis and/or actions of thyroid hormone. Data from genetic mouse models involving disruption and overexpression of components of the thyroid hormone axis also provide direct support for a key role for thyroid hormone in the regulation of bone metabolism. Thyroid hormone regulates proliferation and/or differentiated actions of multiple cell types in bone including chondrocytes, osteoblasts and osteoclasts. Thyroid hormone effects on the target cells are mediated via ligand-inducible nuclear receptors/transcription factors, thyroid hormone receptor (TR) α and β, of which TRα seems to be critically important in regulating bone cell functions. In terms of mechanisms for thyroid hormone action, studies suggest that thyroid hormone regulates a number of key growth factor signaling pathways including insulin-like growth factor-I, parathyroid hormone related protein, fibroblast growth factor, Indian hedgehog and Wnt to influence skeletal growth. In this review we describe findings from various genetic mouse models and clinical mutations of thyroid hormone signaling related mutations in humans that pertain to the role and mechanism of action of thyroid hormone in the regulation of skeletal growth and maintenance. Keywords: thyroid hormone; bone; cartilage; growth factors; bone cells Bone Research (2013) 2: 146-161. doi: 10.4248/BR201302004 IntroductionThyroid hormone (TH) plays an important role in normal endochondral ossification and is essential for skeletal development, linear growth, maintenance of bone mass, and efficient fracture healing ( 1). Juvenile hypothyroidism causes growth arrest with delayed bone formation and mineralization, and T4 replacement induces rapid catch-up growth (2). By contrast, childhood thyrotoxicosis accelerates bone formation with premature closure of the growth plates and skull sutures, leading to short stature and craniosynostosis (3). Although there is considerable evidence regarding the importance of TH in skeletal development, the molecular mechanisms of TH action in bone are poorly understood. In this chapter, we discuss regulation and mechanisms of action of TH during skeletal development with particular emphasis on areas in which recent advances have been made. Physiology of TH: Regulation, metabolism and TH receptorRegulation Systemic TH levels are maintained by the classical negative feedback loop involving the hypothalamus-pituitary--thyroid (HPT) axis ( Figure 1). Thyrotropin releasing hormone (TRH) is synthesized in the paraventricular nucleus (PVN) of the hypothalamus and stimulates synthesis and secretion of thyroid stimulating hormone (TSH) fromHa-Young Kim et al. www.boneresearch.org | Bone Research 147thyrotroph cells in the anterior pituitary gland. TSH subsequently acts via the TSH receptor (TSHR) on thyroid follicular cells to stimulate synthesis and release of 3,5...

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Role of diabetes- and obesity-related protein in the regulation of osteoblast differentiation

Cited by 10 publications

References 44 publications

Differential Expression of Claudin Family Members during Osteoblast and Osteoclast Differentiation: Cldn-1 Is a Novel Positive Regulator of Osteoblastogenesis

Differential Expression of Claudin Family Members during Osteoblast and Osteoclast Differentiation: Cldn-1 Is a Novel Positive Regulator of Osteoblastogenesis

Claudin 18 is a novel negative regulator of bone resorption and osteoclast differentiation

Role and Mechanisms of Actions of Thyroid Hormone on the Skeletal Development

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