As an important component of articular cartilage, type IX collagen plays an important role in regulating homeostasis of bone and cartilage. The mutation or deletion of gene could disequilibrate homeostasis leads to deformity of corresponding bone and joint, and finally causes multiple epiphyseal dysplasia. Moreover, anatomic variation also leads to biomechanics change of corresponding functional unit, combine with micro-environment change caused by change of genes, osteoarthritis and disc degeneration were occurred under the function of stress over and over again. In addition, lack of type IX collagen could effect repair of articular cartilage, intervertebral disc tissue injury. However, musculoskeletal diseases related with type IX collagen has so much not limited this, the reports about it is less for lack of evidence, and need further work to study. Clear relationship of type IX collagen and its disease could provide an effective diagnostic method, and develop a new pathway for follow-up treatment.
Cartilage, Articular ; Collagen ; Collagen Type IX ; Humans ; Intervertebral Disc Degeneration ; Musculoskeletal Diseases

OBJECTIVETo study gene expression of collagen types IX and X in human lumbar intervertebral discs during aging and degeneration and to explore the role of collagen types IX and X in disc degeneration.

METHODSFetal, adult and pathologic specimens were subjected to in situ hybridization with cDNA probes to investigate mRNA-expressions of types IX and X collagen gene.

RESULTSIn fetal intervertebral discs, positive mRNA hybridization signals of type IX collagen were concentrated in the nucleus pulposus and the inner layer of anulus fibrosus. Interstitial matrix of the nucleus pulposus also showed positive type X collagen staining. Positive mRNA hybridization signals of types IX and X were not detected in the middle and outer layers of anulus fibrosus. In adult specimens, expression of type IX collagen mRNA was markedly decreased. No hybridization signals of type X collagen was observed. As for pathological specimens, there was no gene expression of type IX collagen. In severe degenerated discs from adults, there were focal positive expressions of type X collagen.

CONCLUSIONSObvious changes of collagen gene expression occur with aging. Expression of type IX collagen decreases in adult and pathological discs. Results of type X collagen expression suggest that type X collagen is expressed only in older adult and senile discs (i.e., when disc degeneration has already reached a terminal stage), indicating the terminal stage of degeneration.

Adolescent ; Adult ; Collagen Type IX ; metabolism ; Collagen Type X ; metabolism ; Female ; Gene Expression ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Intervertebral Disc ; embryology ; metabolism ; Lumbar Vertebrae ; Male

PURPOSE: The aim of this study was to demonstrate the existence of circulating mesenchymal stem cells (MSC) in the human umbilical cord blood (hUCB) and to evaluate the chondrogenic differentiation potential of hUCB-derived MSC in vitro. MATERIALS AND METHODS: Fifty hUCB harvests were cultured in media supplemented with 10% fetal bovine serum. The adherent fibroblast-like cells were characterized by immunophenotyping and induced to differentiate into chondrocytes in the pellet culture with and without BMP-6. This study performed RTPCR of the chondrogenic markers, Safranin-O stain and type II collagen immunohistochemical stain. RESULTS: The mononuclear cells isolated from hUCB formed adherent colonies with an attached wellspread fibroblast-like morphology. The cells positively expressed the MSC-related antigens, but did not express the hematopoietic, HLA-DR, endothelial, or osteoclast antigens and could be induced to differentiate into chondrocytes under proper stimulation. BMP-6 increased the size of the pellet and the mRNA levels for aggrecan, type II collagen and type IX collagen and enhanced the levels of proteoglycan synthesis during chondrogenic differentiation. CONCLUSION: The homogenous fibroblast-like cells developed in cultures from hUCB with chondrogenic differentiation potential were considered to be MSC. Furthermore, it was found that BMP-6 enhanced chondrogenic differentiation of the hUCB-derived MSC in the pellet culture.
Aggrecans ; Bone Morphogenetic Protein 6 ; Chondrocytes ; Collagen Type II ; Collagen Type IX ; Fetal Blood* ; HLA-DR Antigens ; Humans* ; Immunophenotyping ; Mesenchymal Stromal Cells* ; Osteoclasts ; Proteoglycans ; RNA, Messenger ; Umbilical Cord*

OBJECTIVECOL9A1 gene is located in the susceptibility region of idiopathic congenital talipes equinovarus (ICTEV) (6q12-13). This study aimed to investigate the expression of the COL9A1 gene and the distribution of single nucleotide polymorphism (SNP) of COL9A1 gene in patients with ICTEV and normal controls.

METHODSImmunohistochemistry was used to detect the expression of COL9A1 in 25 children with ICTEV and 5 normal controls. The frequencies of genotypes and allele of two SNPs in COL9A1 gene rs35470562 and rs1135056 were investigated by PCR-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing in 118 patients with ICTEV and 100 normal controls.

RESULTSThe COL9A1 protein expression was significantly higher in 22 (88%) out of 25 children with ICTEV than normal controls. There were significant differences in the frequencies of genotypes and allele of rs1135056 in COL9A1 gene between the ICTEV and the control groups: the G allele frequency was higher, the frequency of AA genotype was lower, and the frequencies of AG and GG genotypes were higher in ICTEV patients than those in healthy controls (P<0.05).

CONCLUSIONSCOL9A1 protein is highly expressed in patients with ICTEV and rs1135056, which is located in the coding region of COL9A1 gene, may be associated with the pathogenesis of ICTEV.

Adolescent ; Child ; Child, Preschool ; Clubfoot ; etiology ; genetics ; Collagen Type IX ; analysis ; genetics ; Humans ; Immunohistochemistry ; Infant ; Polymorphism, Single Nucleotide

OBJECTIVETo study the distribution of collagen IX gene in the disc and to determine its role in the pathogeny of idiopathic scoliosis (IS).

METHODSThe data included apical disc and intermediate disc from 14 cases of adolescent IS, 26 discs from 13 cases of scoliosis of confirmed pathogeny (CPS), which included 10 cases of congenital scoliosis and neurofibromatosis scoliosis. Six discs were obtained from 3 cases of normal young man served as controls. The distribution of collagen IX was studied in the apical disc of IS by immunohistochemistry and in situ hybridization (ISH) with RNA probe. The figure of collagen IX hybridization in the endplate cartilage was input to the figure analysis system. The mRNA content of collagen IX was compared between each group by SPSS software.

RESULTSCollagen IX was mainly distributed in the inner fibrous annulus, nucleus and endplate cartilage. Collagen IX was secreted by the little round chondrocyte-like cells, which was not expressed in the hypertrophic cells. There was significant difference of collagen IX mRNA content between the concave side of apical disc in the IS and the normal disc(P < 0.05), and also between intermediate vertebrae of CS group and normal.

CONCLUSIONSThere is no obvious abnormal distribution of collagen IX in the disc of idiopathic scoliosis. Collagen IX may be related to the pathogensis of IS. More investigation such as quantity analysis and protein function determination is needed to confirm its role in the pathogenicity of IS.

Adolescent ; Adult ; Collagen Type IX ; genetics ; metabolism ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Intervertebral Disc ; metabolism ; RNA, Messenger ; genetics ; Scoliosis ; genetics ; metabolism

OBJECTIVETo analyze the mutation of COL9A2 gene and investigate the molecular pathogenesis of pathological myopia in a Han Chinese population.

METHODSMutation in the coding region of the COL9A2 gene was screened by Sanger sequencing in 200 subjects with pathological myopia and 200 normal controls. The detected variants were genotyped by SNaPshot method in another 200 myopic cases and 200 normal controls.

RESULTSSanger sequencing has failed to detect the reported D281fs frameshift mutation in the 200 cases. A novel variant, c.143G>C heterozygous missense mutation in exon 2, was identified in a myopic subject, and another novel variant, c.884G>A heterozygous missense mutation in exon 17, was found in another case. Neither was found in normal controls. One SNP (rs2228564) was detected in the coding region of the COL9A2 gene, but there was no significant difference in its allelic frequencies between the two groups (P> 0.05). Genotyping of the remainder 200 cases and 200 controls by SNaPshot method has found a c.143G>C in 1 case and c.884G>A in 2 cases, though no significant difference between the two groups was detected (P> 0.05).

CONCLUSIONThe D281fs frameshift mutation in the COL9A2 gene is not associated with pathological myopia in the studied Han Chinese population. Two novel mutations, c.143G>C in exon 2 and c.884G>A in exon 17 of the COL9A2 gene, may contribute to the development of pathological myopia.

Asian Continental Ancestry Group ; genetics ; China ; ethnology ; Collagen Type IX ; genetics ; Frameshift Mutation ; Humans ; Myopia, Degenerative ; genetics ; Sequence Analysis, DNA