Age-Related Reduction in Bone Matrix Protein mRNA Expression in Rat Bone Tissues: Application of Histomorphometry to In Situ Hybridization

Ikeda, T

doi:10.1016/s8756-3282(94)00002-6

Cited by 18 publications

(17 citation statements)

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“…The low expression of ALP and high expression of osteocalcin by MLO‐Y4 cells supports the hypothesis that the MLO‐Y4 cell line is osteocyte‐like as reports by others show this pattern of expression in primary osteocytes (3) . However, the low expression of type I collagen in MLO‐Y4 cells compared with osteoblasts contrasts with a report by Aarden and coworkers (4) but is in agreement with reports by others (21,22) and by Nijweide and coworkers who have found that type I collagen is produced in relatively low abundance by osteocytes compared with osteoblasts (personal communication). Our results are also in conflict with the reports by Hughes and coworkers (3) and Nakamura and coworkers (14) who used immunohistochemical techniques to show that osteocytes are positive for CD44, whereas osteoblast and lining cells are negative.…”

Section: Discussionsupporting

confidence: 89%

Establishment of an Osteocyte-like Cell Line, MLO-Y4

Kato

Windle

Koop

et al. 1997

Journal of Bone and Mineral Research

483

377

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Although osteocytes are the most abundant cells in bone, their functional role remains unclear. In part, this is due to lack of availability of osteocyte cell lines which can be studied in vitro. Since others have shown that cell lines can be readily developed from transgenic mice in which the SV40 large T-antigen oncogene is expressed under the control of a promoter which targets the cells of interest, we used this approach to develop an osteocyte cell line. We chose as a promoter osteocalcin, whose expression is essentially limited to bone cells and which is expressed more abundantly in osteocytes than in osteoblasts. From these transgenic mice, we isolated cells from the long bones using sequential collagenase digestion and maintained these cells on collagen-coated surfaces which are optimal for osteocyte maintenance and growth. We describe here the properties of a cell line cloned from these cultures, called MLO-Y4 (for murine long bone osteocyte Y4). The properties of MLO-Y4 cells are very similar to primary osteocytes. Like primary osteocytes and unlike primary osteoblasts, the cell line produces large amounts of osteocalcin but low amounts of alkaline-phosphatase. The cells produce extensive, complex dendritic processes and are positive for T-antigen, for osteopontin, for the neural antigen CD44, and for connexin 43, a protein found in gap junctions. This cell line also produces very small amounts of type I collagen mRNA compared with primary osteoblasts. MLO-Y4 cells lack detectable mRNA for osteoblast-specific factor 2, which appears to be a positive marker for osteoblasts but may be a negative marker for osteocytes. This newly established cell line should prove useful for studying the effects of mechanical stress on osteocyte function and for determining the means whereby osteocytes communicate with other bone cells such as osteoblasts and osteoclasts.

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Section: Discussionsupporting

confidence: 89%

Establishment of an Osteocyte-like Cell Line, MLO-Y4

Kato

Windle

Koop

et al. 1997

Journal of Bone and Mineral Research

483

377

View full text Add to dashboard Cite

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“…Many researchers have reported extensive heterogeneity in osteoblast gene and protein expression patterns (Aubin et al, 1992, 1993; Heersche et al, 1992; Chen et al, 1993; Ikeda et al, 1995; Liu et al, 1997; Candaliere et al, 2001) (Table 1). For example, in adult rat bone marrow stromal cell cultures, adjacent osteoblasts that appear identical morphologically express very different levels of osteoblast‐associated markers such as osteocalcin, osteonectin (SPARC), and galectin‐3 (Malaval et al, 1994).…”

Section: The Cells Involvedmentioning

confidence: 99%

Buried alive: How osteoblasts become osteocytes

Franz‐Odendaal

Hall

Witten

2005

Developmental Dynamics

614

535

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During osteogenesis, osteoblasts lay down osteoid and transform into osteocytes embedded in mineralized bone matrix. Despite the fact that osteocytes are the most abundant cellular component of bone, little is known about the process of osteoblast-to-osteocyte transformation. What is known is that osteoblasts undergo a number of changes during this transformation, yet retain their connections to preosteoblasts and osteocytes. This review explores the osteoblast-to-osteocyte transformation during intramembranous ossification from both morphological and molecular perspectives. We investigate how these data support five schemes that describe how an osteoblast could become entrapped in the bone matrix (in mammals) and suggest one of the five scenarios that best fits as a model. Those osteoblasts on the bone surface that are destined for burial and destined to become osteocytes slow down matrix production compared to neighbouring osteoblasts, which continue to produce bone matrix. That is, cells that continue to produce matrix actively bury cells producing less or no new bone matrix (passive burial). We summarize which morphological and molecular changes could be used as characters (or markers) to follow the transformation process. Developmental Dynamics 235:176 -190, 2006.

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“…In 1992, for example, Ikeda et al [23] reported on mRNA expression for osteocalcin and osteopontin in bone tissue from newborn and adult rats processed by ISHH. These researchers also reported age-related diminutions in expression levels of osteopontin mRNA that may be indicative of decreased biological activity of bone cells [22].…”

Section: Information Derived From Molecular Histologymentioning

confidence: 94%

“…ISHH has documented expressions of bone matrix proteins, including osteocalcin, osteopontin, and type I collagen associated with cell-to-cell or cell-to-mineralized matrix adhesion [22][23][24][25]. In 1992, for example, Ikeda et al [23] reported on mRNA expression for osteocalcin and osteopontin in bone tissue from newborn and adult rats processed by ISHH.…”

Section: Information Derived From Molecular Histologymentioning

confidence: 99%

Bone biopsy in patients with osteoporosis

Malluche

Mawad²,

Monier‐Faugere³

2007

Curr Osteoporos Rep

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Although rarely used to diagnose and manage patients with osteoporosis, bone biopsies are performed to establish bone quality, including degree of mineralization and microarchitecture; to assess bone turnover and bone loss mechanisms; and to analyze treatment effects on bone structure and bone turnover. Bone biopsies are also the only method to diagnose mineralization defect or frank osteomalacia. Due to the availability of antiresorptive agents and anabolic drugs, determining bone turnover and bone-loss mechanisms is critical to appropriate treatment regimen selection. Bone biopsies establish the safety and efficacy of new therapeutic modalities. Further, new techniques such as molecular morphometry (in situ hybridization and immunohistochemistry) and analysis of bone content and crystal perfection have been applied to undecalcified bone and elucidated pathogenetic mechanisms or abnormalities in bone microstructure.

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Age-Related Reduction in Bone Matrix Protein mRNA Expression in Rat Bone Tissues: Application of Histomorphometry to In Situ Hybridization

Cited by 18 publications

References 0 publications

Establishment of an Osteocyte-like Cell Line, MLO-Y4

Establishment of an Osteocyte-like Cell Line, MLO-Y4

Buried alive: How osteoblasts become osteocytes

Bone biopsy in patients with osteoporosis

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