Temporal expression patterns of BMP receptors and collagen II (B) during periosteal chondrogenesis

Abstract

Articular cartilage has a limited ability to repair itself. Periosteal grafts have chondrogenic potential and are used clinically to repair defects in articular cartilage. An organ culture model system for in vitro rabbit periosteal chondrogenesis has been established to study the molecular events of periosteal chondrogenesis in vitro. In this model, bone morphogenetic protein-2 (BMPZ) mRNA expression was found to be upregulated in the first 12 h. BMPs usually transduce their signals through a receptor complex that includes type 11 and either type IA or type IB BMP receptors. Receptors 1A and IB play distinct roles during limb development. We have examined the temporal expression patterns for the mRNAs of these receptors using our experimental model. The mRNA expression patterns of these three BMP receptors differed from one another in periosteal explants during chondrogenesis. When these explants were cultured under chondrogenic conditions (agarose suspension with TGF-01 added to the media for the first 2 days), the expression of BMPRII mRNA and that of BMPRIA mRNA varied only slightly and persisted over a long time. In contrast, the expression of BMPRIB mRNAwas upregulated within 12 h, peaked at day 5, and fell to a level that was barely detected beyond day 21. Moreover, the expression of BMPRIB mRNA preceded that of collagen type IIB mRNAs, a marker for matrixdepositing chondrocytes. These data support a role for coordinate expression of BMP2 and its receptors early during periosteal chondrogenesis.

Insulin-like Growth Factor-I and Growth Differentiation Factor-5 Promote the Formation of Tissue-Engineered Human Nasal Septal Cartilage

“…35 It is possible that introducing the right growth factors at the right time may significantly improve chondrogenesis. Another limitation, which could affect the ability to generalize these results, is that a single lot of pooled HS was used.…”

Effects of Direct Current Electrical Stimulation on Gene Expression of Osteopromotive Factors in a Posterolateral Spinal Fusion Model

“…Activin receptor-like kinase-3 (ALK-3) sequence was obtained from a published sequence. 11 Rabbit mRNA sequences for bone morphogenetic protein-6 (BMP-6) and activin receptor-like kinase-2 (ALK-2) were not available on GenBank. Primers/probe sets were developed by comparing homologous regions of human and mouse mRNA sequences obtained from NCBI (human BMP-6 NM_001718, human ALK-2 Z22534, mouse BMP-6 AH003686, mouse ALK-2 BB136281).…”

Induction of CD‐RAP mRNA during periosteal chondrogenesis

“…To our knowledge, this is the first investigation of the gene in the context of periosteal chondrogenesis. To achieve our goal we first isolated a rabbit-specific cDNA sequence of CD-RAP by gene digging [40], a method that has been highly successful in our lab to isolate speciesspecific cDNA sequences [9,21,41,42]. The similarity of the isolated cDNA, at both the nucleotide and the deduced amino acid levels, with those of bovine, human and mouse suggests the acquisition of the rabbit homologue of CD-RAP mRNA, a prerequisite for our investigation.…”

“…Periosteal explants cultured in agarose-containing medium with TGF-PI , however, contain more type IIA than IIB on day 10, while more type IIB than type IIA on day 14 and 21 [38]. The timing and expression pattern of CD-RAP resembles collagen type IIB mRNA production [41]. During the development of mouse embryo, the expression of the CD-RAP gene is activated at the beginning of chondrogenesis, and remains elevated throughout cartilage development [6].…”