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Blockade of hypoxia-induced CXCR4 with AMD3100 inhibits production of OA-associated catabolic mediators IL-1β and MMP-13.

Li P, Deng J, Wei X, Jayasuriya CT, Zhou J, Chen Q, Zhang J, Wei L, Wei F - Mol Med Rep (2016)

Bottom Line: Binding of the chemokine stromal cell-derived factor-1 (SDF-1) to its receptor C-X-C chemokine receptor type 4 (CXCR4) results in receptor activation and the subsequent release of matrix metalloproteinases (MMPs) that contribute to osteoarthritis (OA) cartilage degradation.By contrast, such changes did not occur to an appreciable degree in cells that were pretreated with AMD3100.The results of the present study demonstrate that even under hypoxic conditions, where CXCR4 expression is significantly elevated in chondrocytes, AMD3100 effectively blocks this receptor and protects chondrocytes from OA‑induced catabolism, suggesting that the successful inhibition of CXCR4 may be an effective approach for OA treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, The Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair, Taiyuan, Shanxi 030001, P.R. China.

ABSTRACT
Binding of the chemokine stromal cell-derived factor-1 (SDF-1) to its receptor C-X-C chemokine receptor type 4 (CXCR4) results in receptor activation and the subsequent release of matrix metalloproteinases (MMPs) that contribute to osteoarthritis (OA) cartilage degradation. As hypoxia is a defining feature of the chondrocyte microenvironment, the present study investigated the possible mechanism through which SDF‑1 induces cartilage degradation under hypoxic conditions. To do this, OA chondrocyte cultures and patient tissue explants pretreated with the CXCR4 inhibitor, AMD3100 were incubated with SDF‑1. It was identified that hypoxic conditions significantly elevated the expression of CXCR4 in osteoarthritic chondrocytes relative to normoxic conditions. Furthermore, SDF‑1 elevated MMP‑13 mRNA levels and proteinase activity. It also elevated the mRNA and protein levels of runt‑related transcription factor 2, and induced the release of glycosaminoglycans and the inflammatory cytokine, interleukin‑1β. By contrast, such changes did not occur to an appreciable degree in cells that were pretreated with AMD3100. The results of the present study demonstrate that even under hypoxic conditions, where CXCR4 expression is significantly elevated in chondrocytes, AMD3100 effectively blocks this receptor and protects chondrocytes from OA‑induced catabolism, suggesting that the successful inhibition of CXCR4 may be an effective approach for OA treatment.

No MeSH data available.


Related in: MedlinePlus

Hypoxia increases CXCR4 expression in human OA chondrocytes. (A and B) Quantitative analysis of CXCR4 gene expression by reverse transcription-quantitative polymerase chain reaction. (C) Western blot of HIF-1α in OA chondrocytes cultured under normoxic or hypoxic conditions (5 or 2% oxygen, respectively). (D) Band intensities obtained from the three individual western blots were quantified using Image J software to generate a bar graph of the relative difference in Hif-1α protein expression levels. Data are presented as means + standard deviation. CXCR4, C-X-C chemokine receptor type 4; OA, osteoarthritis; HIF-1α, hypoxia-inducible factor 1α.
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f1-mmr-14-02-1475: Hypoxia increases CXCR4 expression in human OA chondrocytes. (A and B) Quantitative analysis of CXCR4 gene expression by reverse transcription-quantitative polymerase chain reaction. (C) Western blot of HIF-1α in OA chondrocytes cultured under normoxic or hypoxic conditions (5 or 2% oxygen, respectively). (D) Band intensities obtained from the three individual western blots were quantified using Image J software to generate a bar graph of the relative difference in Hif-1α protein expression levels. Data are presented as means + standard deviation. CXCR4, C-X-C chemokine receptor type 4; OA, osteoarthritis; HIF-1α, hypoxia-inducible factor 1α.

Mentions: Consistent with previously established methods (22,23), OA articular chondrocytes were maintained in 5% O2 (normoxia) or exposed to 2% O2 (hypoxia) for two days. RT-qPCR analysis demonstrated that CXCR4 expression was significantly higher in OA chondrocytes cultured under hypoxic compared with normoxic conditions (P=0.006; Fig. 1A and B). Protein quantification of HIF-1α via western blotting was performed to confirm that conditions were hypoxic in the in vitro model (P=0.02; Fig. 1C and D). Micrographs of immunocytochemical analysis further identified strong CXCR4 positive staining in hypoxic conditions compared with normoxic conditions (Fig. 2).


Blockade of hypoxia-induced CXCR4 with AMD3100 inhibits production of OA-associated catabolic mediators IL-1β and MMP-13.

Li P, Deng J, Wei X, Jayasuriya CT, Zhou J, Chen Q, Zhang J, Wei L, Wei F - Mol Med Rep (2016)

Hypoxia increases CXCR4 expression in human OA chondrocytes. (A and B) Quantitative analysis of CXCR4 gene expression by reverse transcription-quantitative polymerase chain reaction. (C) Western blot of HIF-1α in OA chondrocytes cultured under normoxic or hypoxic conditions (5 or 2% oxygen, respectively). (D) Band intensities obtained from the three individual western blots were quantified using Image J software to generate a bar graph of the relative difference in Hif-1α protein expression levels. Data are presented as means + standard deviation. CXCR4, C-X-C chemokine receptor type 4; OA, osteoarthritis; HIF-1α, hypoxia-inducible factor 1α.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940083&req=5

f1-mmr-14-02-1475: Hypoxia increases CXCR4 expression in human OA chondrocytes. (A and B) Quantitative analysis of CXCR4 gene expression by reverse transcription-quantitative polymerase chain reaction. (C) Western blot of HIF-1α in OA chondrocytes cultured under normoxic or hypoxic conditions (5 or 2% oxygen, respectively). (D) Band intensities obtained from the three individual western blots were quantified using Image J software to generate a bar graph of the relative difference in Hif-1α protein expression levels. Data are presented as means + standard deviation. CXCR4, C-X-C chemokine receptor type 4; OA, osteoarthritis; HIF-1α, hypoxia-inducible factor 1α.
Mentions: Consistent with previously established methods (22,23), OA articular chondrocytes were maintained in 5% O2 (normoxia) or exposed to 2% O2 (hypoxia) for two days. RT-qPCR analysis demonstrated that CXCR4 expression was significantly higher in OA chondrocytes cultured under hypoxic compared with normoxic conditions (P=0.006; Fig. 1A and B). Protein quantification of HIF-1α via western blotting was performed to confirm that conditions were hypoxic in the in vitro model (P=0.02; Fig. 1C and D). Micrographs of immunocytochemical analysis further identified strong CXCR4 positive staining in hypoxic conditions compared with normoxic conditions (Fig. 2).

Bottom Line: Binding of the chemokine stromal cell-derived factor-1 (SDF-1) to its receptor C-X-C chemokine receptor type 4 (CXCR4) results in receptor activation and the subsequent release of matrix metalloproteinases (MMPs) that contribute to osteoarthritis (OA) cartilage degradation.By contrast, such changes did not occur to an appreciable degree in cells that were pretreated with AMD3100.The results of the present study demonstrate that even under hypoxic conditions, where CXCR4 expression is significantly elevated in chondrocytes, AMD3100 effectively blocks this receptor and protects chondrocytes from OA‑induced catabolism, suggesting that the successful inhibition of CXCR4 may be an effective approach for OA treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedics, The Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair, Taiyuan, Shanxi 030001, P.R. China.

ABSTRACT
Binding of the chemokine stromal cell-derived factor-1 (SDF-1) to its receptor C-X-C chemokine receptor type 4 (CXCR4) results in receptor activation and the subsequent release of matrix metalloproteinases (MMPs) that contribute to osteoarthritis (OA) cartilage degradation. As hypoxia is a defining feature of the chondrocyte microenvironment, the present study investigated the possible mechanism through which SDF‑1 induces cartilage degradation under hypoxic conditions. To do this, OA chondrocyte cultures and patient tissue explants pretreated with the CXCR4 inhibitor, AMD3100 were incubated with SDF‑1. It was identified that hypoxic conditions significantly elevated the expression of CXCR4 in osteoarthritic chondrocytes relative to normoxic conditions. Furthermore, SDF‑1 elevated MMP‑13 mRNA levels and proteinase activity. It also elevated the mRNA and protein levels of runt‑related transcription factor 2, and induced the release of glycosaminoglycans and the inflammatory cytokine, interleukin‑1β. By contrast, such changes did not occur to an appreciable degree in cells that were pretreated with AMD3100. The results of the present study demonstrate that even under hypoxic conditions, where CXCR4 expression is significantly elevated in chondrocytes, AMD3100 effectively blocks this receptor and protects chondrocytes from OA‑induced catabolism, suggesting that the successful inhibition of CXCR4 may be an effective approach for OA treatment.

No MeSH data available.


Related in: MedlinePlus