TY - JOUR
T1 - The adenosine A2a receptor inhibits matrix-induced inflammation in a novel fashion
AU - Scheibner, Kara A.
AU - Boodoo, Sada
AU - Collins, Samuel
AU - Black, Katharine E.
AU - Chan-Li, Yee
AU - Zarek, Paul
AU - Powell, Jonathan D.
AU - Horton, Maureen R.
N1 - Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2009/3/1
Y1 - 2009/3/1
N2 - Endogenous mediators within the inflammatory milieu play a critical role in directing the scope, duration, and resolution of inflammation. High-molecular-weight extracellular matrix hyaluronan (HA) helps to maintain homeostasis. During inflammation, hyaluronan is broken down into fragments that induce chemokines and cytokines, thereby augmenting the inflammatory response. Tissue-derived adenosine, released during inflammation, inhibits inflammation via the anti-inflammatory A2 adenosine receptor (A2aR). We demonstrate that adenosine modulates HA-induced gene expression via the A2aR. A2aR stimulation inhibits HA fragment-induced pro-fibrotic genes TNF-α, keratinocyte chemoattractant (KC), macrophage inflammatory protein (MIP)-2, and MIP-1α while simultaneously synergizing with hyaluronan fragments to up-regulate the TH1 cytokine 1L-12. Interestingly, A2aR stimulation mediates these affects via the novel cAMP-activated guanine nucleotide exchange factor EPAC. In addition, A2aR-null mice are more susceptible to bleomycin-induced lung injury, consistent with a role for endogenous adenosine in inhibiting the inflammation that may lead to fibrosis. Indeed, the bleomycin treated A2aR-null mice demonstrate increased lung inflammation, HA accumulation, and histologic damage. Overall, our data elucidate the opposing roles of tissue-derived HA fragments and adenosine in regulating noninfectious lung inflammation and support the pursuit of A2aR agonists as a means of pharmacologically inhibiting inflammation that may lead to fibrosis.
AB - Endogenous mediators within the inflammatory milieu play a critical role in directing the scope, duration, and resolution of inflammation. High-molecular-weight extracellular matrix hyaluronan (HA) helps to maintain homeostasis. During inflammation, hyaluronan is broken down into fragments that induce chemokines and cytokines, thereby augmenting the inflammatory response. Tissue-derived adenosine, released during inflammation, inhibits inflammation via the anti-inflammatory A2 adenosine receptor (A2aR). We demonstrate that adenosine modulates HA-induced gene expression via the A2aR. A2aR stimulation inhibits HA fragment-induced pro-fibrotic genes TNF-α, keratinocyte chemoattractant (KC), macrophage inflammatory protein (MIP)-2, and MIP-1α while simultaneously synergizing with hyaluronan fragments to up-regulate the TH1 cytokine 1L-12. Interestingly, A2aR stimulation mediates these affects via the novel cAMP-activated guanine nucleotide exchange factor EPAC. In addition, A2aR-null mice are more susceptible to bleomycin-induced lung injury, consistent with a role for endogenous adenosine in inhibiting the inflammation that may lead to fibrosis. Indeed, the bleomycin treated A2aR-null mice demonstrate increased lung inflammation, HA accumulation, and histologic damage. Overall, our data elucidate the opposing roles of tissue-derived HA fragments and adenosine in regulating noninfectious lung inflammation and support the pursuit of A2aR agonists as a means of pharmacologically inhibiting inflammation that may lead to fibrosis.
KW - Adenosine
KW - Chemokines
KW - Hyaluronan
KW - Lung fibrosis
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U2 - 10.1165/rcmb.2008-0168OC
DO - 10.1165/rcmb.2008-0168OC
M3 - Article
C2 - 18703794
AN - SCOPUS:61549122358
SN - 1044-1549
VL - 40
SP - 251
EP - 259
JO - American journal of respiratory cell and molecular biology
JF - American journal of respiratory cell and molecular biology
IS - 3
ER -