Tuesday, January 15, 2013

Ectopic endochondral ossification genes versus LSJL

A gene expression profile for endochondral bone formation: oligonucleotide microarrays establish novel connections between known genes and BMP-2-induced bone formation in mouse quadriceps.

"This study evaluated several aspects of the osteogenic effect of hBMP-2 protein injected into quadriceps of female C57B1/6J SCID mice. Mice were euthanized 1, 2, 3, 4, 7, and 14 days postinjection and muscles were collected for several methods of analysis. Hematoxylin and eosin-stained sections of muscles injected with formulation buffer showed no evidence of osteogenesis. In contrast, sections of muscles injected with hBMP-2 showed evidence of endochondral bone formation that progressed to mineralized bone by day 14. In addition, radiographs of mice injected with hBMP-2 showed that much of the quadriceps muscle had undergone mineralization by day 14. Labeled mRNA solutions were prepared and hybridized to oligonucleotide arrays designed to monitor approximately 1300 murine, full-length genes. Changes in gene expression associated with hBMP-2 were determined from time-matched comparisons between buffer and hBMP-2 samples. A gene expression profile was created for 215 genes that showed greater than 4-fold changes at one or more of the indicated time points. One hundred twenty-two of these genes have previously been associated with bone or cartilage metabolism and showed significant increases in expression, e.g., aggrecan (Agc1){up}, runt related transcription factor 2 (Runx2), bone Gla protein 1 (Bglap1), and procollagens type II (Col2a1){up} and X (Col10a1){up}. In addition, there were 93 genes that have not been explicitly associated with bone or cartilage metabolism. Two of these genes, cytokine receptor-like factor-1 (Crlf1){up} and matrix metalloproteinase 23 (Mmp23), showed peak changes in gene expression of 15- and 40-fold on days 4 and 7, respectively. In situ hybridizations of muscle sections showed that Mmp23 and Crlf1 mRNAs were expressed in chondrocytes and osteoblasts, suggesting a role for both proteins in some aspect of cartilage or bone formation"

"BMP-2-induced changes in the expression of gene"

Genes upregulated on Day2-3 versus LSJL:
Col6a1(no change on day 1) {up}

No Change Day1-3 with some transient upregulation(noted if occurred) versus LSJL:
Sdc2 {down}
Vcam1 (transient on day 2) {down}
Col6a2 {up and down}
Lum {up}
Bsp {up}
Col2a1 (transient decrease on day 3) {down}
Wisp2 {up}
Agc1 {up}
Cd9 {down}
Ptpra {down}
Anxa8 {up}
Socs3 (transient increase on day 2) {up}
Ptpn12 {down}

Generally Downregulated:
Col10a1 {up}
Col9a1 {up}
Col15a1 {up}
Eln {up}
Col9a3 {up}

Full-size image (305 K)"Ectopic cartilage induced: A histological time course of the effects of a single intramuscular injection of buffer or hBMP-2 protein into quadriceps muscles of C57B1/6J SCID females. A, C, E, G, and I correspond to muscles removed after 1, 3, 4, 7, and 14 days, respectively, following an injection of formulation buffer. B, D, F, H, and J correspond to muscles removed after 1, 3, 4, 7, and 14 days, respectively, following an injection of 50 μg of hBMP-2 protein. Muscles were fixed and stained with H&E as described under Methods. Abbreviations: M, normal skeletal muscle fiber; I, inflammatory cells; DM, degenerated skeletal muscle fiber; F, fibroplasia; Cb, chondroblast; C, chondrocyte; Ob, osteoblast; Oc, osteoclast; B, bone; BM, bone marrow. The bar in each panel = 0.1 mm."

"The expression profile for cytokine receptor-like factor 1 (Crlf1) is qualitatively similar to that of Cyr61 and peaks on day 4"<-Crlf1 and Cyr61 may be key components of the chondroinduction by LSJL.

This study has a lot of useful information which will neccessitate returning to it in the future.


  1. Has their been any analysis on the gene MMP-1,MMP-8,MMP-9 and MMP-13. Or any other genes relating to OA

  2. MMP-13 for example is a marker for endochondral ossification. You'd have to detect for it specifically in the articular cartilage as you'd want it in the growth plate and bone area.