A2B adenosine receptor activity is reduced in neutrophils from patients with systemic sclerosis.
We conducted the present study to investigate protein expression and functioning of A2A and A2B adenosine receptors (ARs) in neutrophils of patients affected by systemic sclerosis (SSc). The presence of A2A and A2B ARs was assessed by immunoblotting using specific antibodies. Equilibrium A2A and A2B ARs binding parameters were evaluated by radioligand binding assay. Functional studies were conducted to investigate coupling of the A2B AR to the adenylyl cyclase pathway. This is the first report of the use of Western blot analysis to confirm the presence of A2A and A2B ARs in human neutrophils. No significant changes in A2A AR binding parameters or expression levels were detected between SSc patients and healthy control individuals. A significant decrease (65%) in the maximum density of A2B AR binding sites occurred in SSc neutrophils, whereas no changes in the affinity constant values were found. Moreover, a decrease in A2B AR mediated adenylyl cyclase activity was observed in patients with SSc. Our findings demonstrate the occurrence of selective alterations in A2B AR density and signalling in SSc.
Bazzichi
Laura
L
Department of Internal Medicine, Division of Rheumatology, University of Pisa, Pisa, Italy. l.bazzichi@int.med.unipi.it
Trincavelli
Letizia
L
Rossi
Alessandra
A
De Feo
Francesca
F
Lucacchini
Antonio
A
Bombardieri
Stefano
S
Martini
Claudia
C
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000502:physiology; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000097:blood; D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000097:blood* / Q000276:immunology / Q000473:pathology; D015153:Blotting, Western; D000242:Cyclic AMP / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000737:chemistry* / Q000473:pathology; D010627:Phenethylamines / Q000378:metabolism; D011869:Radioligand Assay; D043705:Receptor, Adenosine A2A / Q000097:blood; D043704:Receptor, Adenosine A2B / Q000097:blood* / Q000172:deficiency / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D012595:Scleroderma, Systemic / Q000097:blood* / Q000276:immunology / Q000473:pathology; D015398:Signal Transduction
D010627:Phenethylamines; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B; D043562:Receptors, G-Protein-Coupled; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D000241:Adenosine
J Am Acad Dermatol. 1996 Aug;35(2 Pt 2):288-90
8698907
Am J Respir Cell Mol Biol. 1997 May;16(5):531-7
9160835
Shock. 2001 Apr;15(4):297-301
11303729
J Immunol. 1986 Nov 15;137(10):3284-9
3021850
Biochem Pharmacol. 2000 Oct 1;60(7):993-9
10974209
Scand J Clin Lab Invest Suppl. 1968;97:77-89
4179068
Biochem Pharmacol. 1998 Mar 1;55(5):627-33
9515573
Adv Cyclic Nucleotide Res. 1979;10:35-55
222124
Ann Rheum Dis. 2001 Jun;60(6):592-8
11350848
J Immunol. 1992 Apr 1;148(7):2201-6
1347551
J Exp Med. 1988 Mar 1;167(3):1186-94
2832507
Clin Immunol Immunopathol. 1987 Jan;42(1):76-85
3024892
Biochem J. 1992 Feb 1;281 ( Pt 3):631-5
1311169
J Clin Invest. 1986 Sep;78(3):760-70
3745437
Biochem Pharmacol. 2001 Jun 15;61(12):1551-9
11377385
Biochem Biophys Res Commun. 2003 Jan 17;300(3):712-8
12507508
Arch Immunol Ther Exp (Warsz). 1994;42(1):33-4
7503631
J Am Acad Dermatol. 1992 Sep;27(3):411-4
1401277
Inflammation. 1985 Sep;9(3):309-20
4044027
J Am Acad Dermatol. 1993 Jan;28(1):78-85
8425975
Acta Derm Venereol. 1995 Jul;75(4):297-9
8578953
J Exp Med. 2003 Sep 1;198(5):783-96
12939345
J Immunol. 1997 Jun 1;158(11):5400-8
9164961
J Rheumatol. 1999 Oct;26(10):2159-67
10529133
Adv Exp Med Biol. 1998;431:89-94
9598037
Methods Enzymol. 1994;238:31-56
7799798