Modification of the transcriptomic response to renal ischemia/reperfusion injury by lipoxin analog.
BACKGROUND
Lipoxins are lipoxygenase-derived eicosanoids with anti-inflammatory and proresolution bioactivities in vitro and in vivo. We have previously demonstrated that the stable synthetic LXA4 analog 15-epi-16-(FPhO)-LXA4-Me is renoprotective in murine renal ischemia/reperfusion injury, as gauged by lower serum creatinine, attenuated leukocyte infiltration, and reduced morphologic tubule injury.


METHODS
We employed complementary oligonucleotide microarray and bioinformatic analyses to probe the transcriptomic events that underpin lipoxin renoprotection in this setting.


RESULTS
Microarray-based analysis identified three broad categories of genes whose mRNA levels are altered in response to ischemia/reperfusion injury, including known genes previously implicated in the pathogenesis of ischemia/reperfusion injury [e.g., intercellular adhesion molecule-1 (ICAM-1), p21, KIM-1], known genes not previously associated with ischemia/reperfusion injury, and cDNAs representing yet uncharacterized genes. Characterization of expressed sequence tags (ESTs) displayed on microarrays represents a major challenge in studies of global gene expression. A bioinformatic annotation pipeline successfully annotated a large proportion of ESTs modulated during ischemia/reperfusion injury. The differential expression of a representative group of these ischemia/reperfusion injury-modulated genes was confirmed by real-time polymerase chain reaction. Prominent among the up-regulated genes were claudin-1, -3, and -7, and ADAM8. Interestingly, the former response was claudin-specific and was not observed with other claudins expressed by the kidney (e.g., claudin-8 and -6) or indeed with other components of the renal tight junctions (e.g., occludin and junctional adhesion molecule). Noteworthy among the down-regulated genes was a cluster of transport proteins (e.g., aquaporin-1) and the zinc metalloendopeptidase meprin-1 beta implicated in renal remodeling.


CONCLUSIONS
Treatment with the lipoxin analog 15-epi-16-(FPhO)-LXA4-Me prior to injury modified the expression of many differentially expressed pathogenic mediators, including cytokines, growth factors, adhesion molecules, and proteases, suggesting a renoprotective action at the core of the pathophysiology of acute renal failure (ARF). Importantly, this lipoxin-modulated transcriptomic response included many genes expressed by renal parenchymal cells and was not merely a reflection of a reduced renal mRNA load resulting from attenuated leukocyte recruitment. The data presented herein suggest a framework for understanding drivers of kidney injury in ischemia/reperfusion and the molecular basis for renoprotection by lipoxins in this setting.
Kieran
Niamh E
NE
Human Genomics and Bioinformatics Research Unit, Department of Medicine and Therapeutics, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Mater Misericordiae Hospital, Dublin 7, Ireland.
Doran
Peter P
PP
Connolly
Susan B
SB
Greenan
Marie-Claire
MC
Higgins
Debra F
DF
Leonard
Martin
M
Godson
Catherine
C
Taylor
Cormac T
CT
Henger
Anna
A
Kretzler
Matthias
M
Burne
Melissa J
MJ
Rabb
Hamid
H
Brady
Hugh R
HR
D051722:ADAM Proteins; D058186:Acute Kidney Injury / Q000188:drug therapy / Q000503:physiopathology; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D062445:Claudin-1; D062465:Claudin-3; D057167:Claudins; D018076:DNA, Complementary; D004815:Epidermal Growth Factor / Q000235:genetics; D007668:Kidney / Q000503:physiopathology*; D044045:Lipoxins / Q000494:pharmacology*; D008565:Membrane Proteins / Q000235:genetics; D008666:Metalloendopeptidases / Q000235:genetics; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D015427:Reperfusion Injury / Q000188:drug therapy* / Q000503:physiopathology*; D014158:Transcription, Genetic / Q000187:drug effects*
C447621:16-(4-fluorophenoxy)lipoxin A4; D015703:Antigens, CD; C568108:CLDN1 protein, human; C568122:CLDN3 protein, human; C473255:CLDN7 protein, human; D062445:Claudin-1; D062465:Claudin-3; D057167:Claudins; C568113:Cldn1 protein, mouse; C568123:Cldn3 protein, mouse; D018076:DNA, Complementary; D044045:Lipoxins; D008565:Membrane Proteins; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D051722:ADAM Proteins; C489402:Adam8 protein, mouse; D008666:Metalloendopeptidases; C095663:meprin B