Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose:
We have previously demonstrated that the nucleoside adenosine stimulates collagen production and induces dermal fibrosis in vitro and in vivo. Recent studies have demonstrated the presence and significance of microRNAs in various disease conditions and, in fibrosing conditions, diminished levels of miR-29a are found in the skin and other organs that have undergone fibrosis. We therefore determined whether adenosine A2AR stimulation regulates the expression and levels of miR29a in skin at fibrotic sites.
Methods:
In this investigation, human dermal fibroblasts were treated with the A2AR specific agonist (CGS21680). Changes in miR-29a, collagen1 and collagen3 expression were analyzed by real-time PCR. An in vivo model of hypertrophic scarring previously described (Perez-Aso et al. 2012) was used to analyze the impact of A2AR pharmacological blockade with the specific A2AR antagonist ZM241385 on miR-29a expression in the skin: 12mm incisional wounds were splinted to promote chronic scarring in a total of 32 C57BL/6 mice. Mice were topically treated with either the A2AR antagonist or vehicle (3% carboxymethylcellulose and 7.4% DMSO) alone as a control. Scar progression was quantified using trichrome staining for collagen deposition.
Results:
In in vitro studies A2AR stimulation with increasing concentrations of CGS21680 (0.01, 0.1 and 1μM) reduced the expression of miR-29a (table 1) and the A2AR agonist CGS21680 (1μM) stimulated an increase of both collagen1 and collagen3 (table 2). In vivo investigation yielded parallel results. Trichrome stains revealed that collagen deposition in the scar was reduced by topical application of the A2AR antagonist ZM241385 (2.5mg/ml). Changes in miR-29a expression in the scar were analyzed at the end of the investigation. Scarring decreased miR-29a expression by 46.3±4.8%; (P<0.001 vs unwounded skin, n=7) and A2AR blockade with the antagonist ZM241385 stimulated a dramatic increase of miR29a (191.7±4.8% of unwounded skin; ZM241385 vs vehicle P<0.01, n=7).
Conclusion:
The findings of the present work indicate that A2AR activation represses miR-29a in vitro and, in a similar fashion, in vivo. These findings indicate that targeting A2AR may be a novel therapeutic target in scleroderma that mediates its action, at least in part, by diminishing miR29a, in promoting wound healing and preventing pathologic fibrosis such as that observed in hypertrophic scarring or scleroderma.
Table 1
|
CGS21680 (µM) |
|
0.01 |
|
0.1 |
|
1 |
|||
|
|
|
|
|||||||
|
miR-29a inhibition (%) |
28.3 |
57.5 |
32.9 |
50.5 |
11.1 |
46 |
|||
|
|
|
|
Table 2
|
Collagen 1 (% of control) |
143.3 |
252.3 |
|
|
Collagen 3 (% of control) |
282.2 |
218.9 |
Disclosure:
R. C. Radusky,
None;
M. Perez-Aso,
None;
A. G. Franks Jr.,
Stiefel Pharmaceuticals,
5;
B. N. Cronstein,
Canfite Pharma,
1,
NIH, Gilead, Takeda, AstraZeneca,
2,
NYU School of Medicine,
3,
Merck-SeronoBristol-Myers Squibb, Novartis, CanFite Biopharmaceuticals, Cypress Laboratories, Regeneron (Westat, DSMB), Endocyte, Protalex, Allos, Inc., Savient, Gismo Therapeutics, Antares Pharmaceutical, Medivector,
5,
Multiple patents on adenosine receptors and bone metabolism, pharmacology,
9;
E. S. Chan,
Patent on the use of adenosine A2A antagonists for the treatment of fibrosis.,
9.
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