Regulation of the IGFBP-5 and MMP-13 genes by the microRNAs miR-140 and miR-27a in human osteoarthritic chondrocytes

<p>Abstract</p> <p>Background</p> <p>MMP-13 and IGFBP-5 are important factors involved in osteoarthritis (OA). We investigated whether two highly predicted microRNAs (miRNAs), miR-140 and miR-27a, regulate these two genes in human OA chondrocytes.</p> <p>Methods</p> <p>Gene expression was determined by real-time PCR. The effect of each miRNA on IGFBP-5 and MMP-13 expression/production was evaluated by transiently transfecting their precursors (pre-miRNAs) and inhibitors (anti-miRNAs) into human OA chondrocytes. Modulation of IGFBP-5, miR-140 and miR-27a expression was determined upon treatment of OA chondrocytes with cytokines and growth factors.</p> <p>Results</p> <p>IGFBP-5 was expressed in human chondrocytes with its level significantly lower (p < 0.04) in OA. Five computational algorithms identified miR-140 and miR-27a as possible regulators of MMP-13 and IGFBP-5 expression. Data showed that both miRNAs were expressed in chondrocytes. There was a significant reduction (77%, p < 0.01) in miR-140 expression in OA compared to the normal chondrocytes, whereas miR-27a expression was only slightly decreased (23%). Transfection with pre-miR-140 significantly decreased (p = 0.0002) and with anti-miR-140 significantly increased (p = 0.05) IGFBP-5 expression at 24 hours, while pre-miR-27a did not affect either MMP-13 or IGFBP-5. Treatment with anti-miR-27a, but not with anti-miR-140, significantly increased the expression of both MMP-13 (p < 0.05) and IGFBP-5 (p < 0.01) after 72 hours of incubation. MMP-13 and IGFBP-5 protein production followed the same pattern as their expression profile. These data suggest that IGFBP-5 is a direct target of miR-140, whereas miR-27a down-regulates, likely indirectly, both MMP-13 and IGFBP-5.</p> <p>Conclusion</p> <p>This study is the first to show the regulation of these miRNAs in human OA chondrocytes. Their effect on two genes involved in OA pathophysiology adds another level of complexity to gene regulation, which could open up novel avenues in OA therapeutic strategies.</p

Transplantation of adenovirally transduced allogeneic chondrocytes into articular cartilage defects in vivo

SummaryGene transfer to chondrocytes followed by intra-articular transplantation may allow for functional modulation of chondrocyte biology and enhanced repair of damaged articular cartilage. We chose to examine the loss of chondrocytes transduced with a recombinant adenovirus containing the gene for Escherichia coli α-galactosidase (Ad.RSVntlacZ), followed by transplantation into deep and shallow articular cartilage defects using New Zealand White rabbits as an animal model. A type I collagen matrix was used as a carrier for the growth of the transduced chondrocytes and to retain the cells within the surgically created articular defects. Histochemical analysis of matrices recovered from the animals 1, 3 and 10 days after implantation showed the continued loss of lacZ positive chondrocytes. The number of cells recovered from the matrices was also compared with the initial innoculum of transduced cells present within the matrices at the time of implantation. The greatest loss of transduced cells was observed in the first 24 h after implantation. The numbers of transduced cells present within the matrices were relatively constant between 1 and 3 days postimplantation, but had progressively declined by 10 days postimplantation. These results suggest that transduction of chondrocytes followed by intra-articular transplantation in this rabbit model may enable us to examine the biological effects of focal transgenic overexpression of proteins involved in cartilage homeostasis and repair

Selective matrix metalloproteinase inhibition increases breaking strength and reduces anastomotic leakage in experimentally obstructed colon

PURPOSE: Colonic obstruction causes loss of collagen and impairment of anastomotic integrity by matrix metalloproteinases (MMPs). Unexpectedly, pharmacological MMP inhibition increased anastomotic leakage (AL) in obstructed colon possibly due to the non-selective nature of these compounds and the experimental model applied. We therefore studied the effects of selective MMP inhibition on the healing of anastomoses in colon obstructed by a novel laparoscopic technique.METHODS: Left colon was obstructed in 38 male Sprague-Dawley rats (226-284 g). After 12 h, stenoses were resected and end-to-end anastomoses constructed. Baseline breaking strength was determined in 6 animals on day 0. The remaining 32 rats were randomized to daily treatment with the selective MMP-8, MMP-9, and MMP-12 inhibitor AZD3342 (n = 16) or vehicle (n = 16). On day 3, anastomoses were evaluated for AL and breaking strength. Isolated anastomotic wound tissue was analyzed on total collagen and pepsin-insoluble and pepsin-soluble collagen by hydroxyproline. The soluble collagens were further differentiated into native, measured by Sircol, and fragmented forms.RESULTS: Baseline breaking strength was maintained with AZD3342 but decreased by 25% (P = 0.023) in the vehicle group. The anastomotic breaking strength of AZD3342-treated rats was 44% higher (P = 0.008) than the vehicle-treated rats. Furthermore, the AL rate was reduced (P = 0.037) with AZD3342 compared with vehicle treatment. AZD3342 treatment influenced neither the total or insoluble collagen concentrations nor the degree of fragmentation of the soluble collagen triple helices.CONCLUSION: Selective MMP inhibition increased anastomotic breaking strength and reduced AL after resection of colonic obstruction.</p