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IGFBP-5 Metabolism Is Disrupted in the Rat Medial Meniscal Tear Model of Osteoarthritis.

Yates MP, Settle SL, Yocum SA, Aggarwal P, Vickery LE, Aguiar DJ, Skepner AP, Kellner D, Weinrich SL, Sverdrup FM - Cartilage (2010)

Bottom Line: This activity was stimulated by calcium and was sensitive to serine protease inhibitors as well as peptide PB-145.Inhibition of IGFBP-5 proteolysis protected cartilage from lesion development and enhanced cartilage turnover.These data are consistent with IGFBP-5 playing a positive role in anabolic IGF signaling in cartilage.

View Article: PubMed Central - PubMed

Affiliation: Pfizer Global Research and Development, Chesterfield, Missouri.

ABSTRACT
Insulin-like growth factor binding protein 5 (IGFBP-5) has been proposed to promote cartilage anabolism through insulin-like growth factor (IGF-1) signaling. A proteolytic activity towards IGFBP-5 has been detected in synovial fluids from human osteoarthritic (OA) joints. The purpose of this study was to determine if protease activity towards IGFBP-5 is present in the rat medial meniscal tear (MMT) model of OA and whether inhibition of this activity would alter disease progression. Sprague-Dawley rats were subject to MMT surgery. Synovial fluid lavages were assessed for the presence of IGFBP-5 proteolytic activity. Treatment animals received intra-articular injections of vehicle or protease inhibitor peptide PB-145. Cartilage lesions were monitored by India ink staining followed by macroscopic measurement of lesion width and depth. The MMT surgery induced a proteolytic activity towards IGFPB-5 that was detectable in joint fluid. This activity was stimulated by calcium and was sensitive to serine protease inhibitors as well as peptide PB-145. Significantly, intra-articular administration of PB-145 after surgery protected cartilage from lesion development. PB-145 treatment also resulted in an increase in cartilage turnover as evidenced by increases in serum levels of procollagen type II C-propeptide (CPII) as well as synovial fluid lavage levels of collagen type II neoepitope (TIINE). IGFBP-5 metabolism is disrupted in the rat MMT model of OA, potentially contributing to cartilage degradation. Inhibition of IGFBP-5 proteolysis protected cartilage from lesion development and enhanced cartilage turnover. These data are consistent with IGFBP-5 playing a positive role in anabolic IGF signaling in cartilage.

No MeSH data available.


Related in: MedlinePlus

Evaluation of protease activity towards IGFBP-5 in synovial fluid lavages from rat knees after medial meniscal tear (MMT). The right knees of 6 rats were subject to MMT surgery. Two weeks after surgery, synovial fluid lavages were obtained from both the surgery (right, r) and control (left, l) knees. Aliquots of synovial fluid lavage were incubated with purified recombinant IGFBP-5 for 30 minutes. The reactions were then subject to SDS-PAGE and blotted with antisera to IGFBP-5 in order to determine the levels of intact and degraded IGFBP-5.
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fig1-1947603509359189: Evaluation of protease activity towards IGFBP-5 in synovial fluid lavages from rat knees after medial meniscal tear (MMT). The right knees of 6 rats were subject to MMT surgery. Two weeks after surgery, synovial fluid lavages were obtained from both the surgery (right, r) and control (left, l) knees. Aliquots of synovial fluid lavage were incubated with purified recombinant IGFBP-5 for 30 minutes. The reactions were then subject to SDS-PAGE and blotted with antisera to IGFBP-5 in order to determine the levels of intact and degraded IGFBP-5.

Mentions: In order to characterize the rat MMT model, we first examined whether a proteolytic activity towards IGFBP-5 would be detectable in joint fluid lavages of rats at various time points after MMT surgery. Samples of MMT synovial fluid lavage were incubated with recombinant IGFBP-5 and proteolysis determined by Western analysis of intact versus fragmented IGFBP-5. As shown in Figure 1, a potent proteolytic activity is present in fluids from surgery knees 2 weeks after MMT that is not present in the contralateral control knee fluids. Specific proteolytic fragments of IGFBP-5 common only to samples incubated with MMT synovial fluid are evident. This activity was similarly detected in and specific to surgery knee synovial fluid lavages from animals at 1 and 3 weeks after MMT (data not shown).


IGFBP-5 Metabolism Is Disrupted in the Rat Medial Meniscal Tear Model of Osteoarthritis.

Yates MP, Settle SL, Yocum SA, Aggarwal P, Vickery LE, Aguiar DJ, Skepner AP, Kellner D, Weinrich SL, Sverdrup FM - Cartilage (2010)

Evaluation of protease activity towards IGFBP-5 in synovial fluid lavages from rat knees after medial meniscal tear (MMT). The right knees of 6 rats were subject to MMT surgery. Two weeks after surgery, synovial fluid lavages were obtained from both the surgery (right, r) and control (left, l) knees. Aliquots of synovial fluid lavage were incubated with purified recombinant IGFBP-5 for 30 minutes. The reactions were then subject to SDS-PAGE and blotted with antisera to IGFBP-5 in order to determine the levels of intact and degraded IGFBP-5.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4440612&req=5

fig1-1947603509359189: Evaluation of protease activity towards IGFBP-5 in synovial fluid lavages from rat knees after medial meniscal tear (MMT). The right knees of 6 rats were subject to MMT surgery. Two weeks after surgery, synovial fluid lavages were obtained from both the surgery (right, r) and control (left, l) knees. Aliquots of synovial fluid lavage were incubated with purified recombinant IGFBP-5 for 30 minutes. The reactions were then subject to SDS-PAGE and blotted with antisera to IGFBP-5 in order to determine the levels of intact and degraded IGFBP-5.
Mentions: In order to characterize the rat MMT model, we first examined whether a proteolytic activity towards IGFBP-5 would be detectable in joint fluid lavages of rats at various time points after MMT surgery. Samples of MMT synovial fluid lavage were incubated with recombinant IGFBP-5 and proteolysis determined by Western analysis of intact versus fragmented IGFBP-5. As shown in Figure 1, a potent proteolytic activity is present in fluids from surgery knees 2 weeks after MMT that is not present in the contralateral control knee fluids. Specific proteolytic fragments of IGFBP-5 common only to samples incubated with MMT synovial fluid are evident. This activity was similarly detected in and specific to surgery knee synovial fluid lavages from animals at 1 and 3 weeks after MMT (data not shown).

Bottom Line: This activity was stimulated by calcium and was sensitive to serine protease inhibitors as well as peptide PB-145.Inhibition of IGFBP-5 proteolysis protected cartilage from lesion development and enhanced cartilage turnover.These data are consistent with IGFBP-5 playing a positive role in anabolic IGF signaling in cartilage.

View Article: PubMed Central - PubMed

Affiliation: Pfizer Global Research and Development, Chesterfield, Missouri.

ABSTRACT
Insulin-like growth factor binding protein 5 (IGFBP-5) has been proposed to promote cartilage anabolism through insulin-like growth factor (IGF-1) signaling. A proteolytic activity towards IGFBP-5 has been detected in synovial fluids from human osteoarthritic (OA) joints. The purpose of this study was to determine if protease activity towards IGFBP-5 is present in the rat medial meniscal tear (MMT) model of OA and whether inhibition of this activity would alter disease progression. Sprague-Dawley rats were subject to MMT surgery. Synovial fluid lavages were assessed for the presence of IGFBP-5 proteolytic activity. Treatment animals received intra-articular injections of vehicle or protease inhibitor peptide PB-145. Cartilage lesions were monitored by India ink staining followed by macroscopic measurement of lesion width and depth. The MMT surgery induced a proteolytic activity towards IGFPB-5 that was detectable in joint fluid. This activity was stimulated by calcium and was sensitive to serine protease inhibitors as well as peptide PB-145. Significantly, intra-articular administration of PB-145 after surgery protected cartilage from lesion development. PB-145 treatment also resulted in an increase in cartilage turnover as evidenced by increases in serum levels of procollagen type II C-propeptide (CPII) as well as synovial fluid lavage levels of collagen type II neoepitope (TIINE). IGFBP-5 metabolism is disrupted in the rat MMT model of OA, potentially contributing to cartilage degradation. Inhibition of IGFBP-5 proteolysis protected cartilage from lesion development and enhanced cartilage turnover. These data are consistent with IGFBP-5 playing a positive role in anabolic IGF signaling in cartilage.

No MeSH data available.


Related in: MedlinePlus