Genotoxic stress and activation of novel DNA repair enzymes in human endothelial cells and in the retinas and kidneys of streptozotocin diabetic rats.
BACKGROUND
Mammalian excision repair cross-complementing 1 (ERCC1) and ERCC4 (a.k.a xeroderma pigmentosum complementation group F) are nucleotide excision repair enzymes, which excise the 5' end of damaged DNA. ERCC1 and ERCC4 have an interactive relationship with poly (adenosine diphosphate ribose) polymerase (PARP). We studied the role of ERCC1 and ERCC4 in glucose-induced extracellular matrix protein production in human endothelial cells and in the retinas and kidneys of streptozotocin diabetic rats.


METHODS
Human umbilical vein endothelial cells were grown with low (5 mM) and high glucose (25 mM). The cells were subjected to ERCC1 and ERCC4 small interfering RNA transfections, PARP blocker (3-aminobenzamide, ABA) and p300 blocker (curcumin). Retinas and kidneys from 1-month-old streptozotocin diabetic rats with or without treatment with curcumin and ABA were examined. Cells and tissues were studied for oxidative stress markers, fibronectin, ERCC1 and ERCC4, PARP and p300 mRNA. Western blot of nuclear proteins was performed.


RESULTS
ERCC1 and ERCC4 messenger RNA and protein levels were higher in high glucose than in low glucose, along with increasing oxidative stress and augmented p300 and fibronectin production. ABA, curcumin, ERCC1 and ERCC4 silencing reduced such upregulations and oxidative stress. Similar changes were seen in the kidneys and retinas of diabetic rats. ABA and curcumin treatment significantly reduced such changes.


CONCLUSIONS
These data indicate that glucose-induced ERCC1 and ERCC4 upregulation leads to increased fibronectin production via a p300-dependent pathway in umbilical endothelial cells, as well as in the retina and in the kidneys of streptozotocin diabetic rats. ERCC1 and ERCC4 may play important roles in the development of diabetic retinopathy and nephropathy.
Department of Pathology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.
Chunyan
C
Wang
Biju
B
George
Shali
S
Chen
Biao
B
Feng
Xiaokun
X
Li
Subrata
S
Chakrabarti
D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D015153:Blotting, Western; D003474:Curcumin / Q000494:pharmacology; D004249:DNA Damage / Q000502:physiology*; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology* / Q000235:genetics; D042783:Endothelial Cells / Q000201:enzymology*; D004789:Enzyme Activation; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000201:enzymology*; D008297:Male; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000737:chemistry / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000201:enzymology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001549:Benzamides; D004268:DNA-Binding Proteins; D005353:Fibronectins; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D034741:RNA, Small Interfering; C095888:xeroderma pigmentosum group F protein; D012313:RNA; C025160:3-aminobenzamide; D011065:Poly(ADP-ribose) Polymerases; D045643:DNA Repair Enzymes; C559906:ERCC1 protein, rat; D003474:Curcumin