Activation of adenosine A2A receptors restores the altered cell-cycle machinery during impaired wound healing in genetically diabetic mice.
BACKGROUND
Cyclins drive cell-cycle progression by associating with their kinase partners, cyclin-dependent kinases (CDK). We investigated cyclin D1/CDK6, cyclin E/CDK2 complexes, and the cell-cycle negative regulators p15 and p27 in an incisional skin wound model.


METHODS
Wounds were produced on the back of female diabetic mice and their normoglycemic littermates. Animals were treated with polydeoxyribonucleotide (PDRN, 8 mg/kg/i.p.), an agonist of adenosine A2(A) receptors, or its vehicle daily. Granulation tissue proliferation by Ki67 immunostaining, cyclin D/CDK6 and cyclin E/CDK2 complexes, and p21 and p16 proteins (Western blot analysis), and the histologic changes were assessed at different days (3, 6, and 12 days after injury).


RESULTS
Numerous Ki67 positive cells were observed at day 3 and day 6 in the granulation tissue of normoglycemic mice. Ki67 positive cells were fewer in diabetic than in normoglycemic mice. PDRN increased Ki67 positive cells in diabetic mice. Normoglycemic mice showed the greatest upregulation of cyclin D1, CDK6, cyclin E, and CDK2 at day 6. Diabetic mice had a markedly lower expression of cyclin D1, CDK6, cyclin E, and CDK2 at day 6. They also showed a greater expression of p15 and p27 at day 6. PDRN administration in diabetic mice increased cyclin D1/CDK6 and cyclin E/CDK2 expression and reduced p15 and p27 inhibitors at day 6 after injury; moreover, it improved the impaired wound healing at day 12.


CONCLUSIONS
Our results suggest that adenosine A2(A) receptor activation by PDRN might represent a therapeutic strategy to overcome the diabetes-impaired cell-cycle machinery.
Altavilla
Domenica
D
Department of Clinical and Experimental Medicine and Pharmacology, School of Medicine, University of Messina, Messina, Italy.
Squadrito
Francesco
F
Polito
Francesca
F
Irrera
Natasha
N
Calò
Margherita
M
Lo Cascio
Patrizia
P
Galeano
Mariarosaria
M
La Cava
Letizia
L
Minutoli
Letteria
L
Marini
Herbert
H
Bitto
Alessandra
A
D000818:Animals; D002453:Cell Cycle; D049109:Cell Proliferation; D019938:Cyclin D1 / Q000032:analysis; D019927:Cyclin E / Q000032:analysis; D051357:Cyclin-Dependent Kinase 2 / Q000032:analysis; D051361:Cyclin-Dependent Kinase 6 / Q000032:analysis; D050760:Cyclin-Dependent Kinase Inhibitor p27; D003920:Diabetes Mellitus / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006097:Granulation Tissue / Q000473:pathology; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D011089:Polydeoxyribonucleotides / Q000494:pharmacology; D043705:Receptor, Adenosine A2A / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology*
C436291:CDKN1B protein, human; D019927:Cyclin E; D047908:Intracellular Signaling Peptides and Proteins; D011089:Polydeoxyribonucleotides; D043705:Receptor, Adenosine A2A; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; C495893:Cdk2 protein, mouse; C495912:Cdk6 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D051361:Cyclin-Dependent Kinase 6