TY - JOUR
T1 - Activated macrophages inhibit enterocyte gap junctions via the release of nitric oxide
AU - Anand, Rahul J.
AU - Dai, Shipan
AU - Rippel, Christopher
AU - Leaphart, Cynthia
AU - Qureshi, Faisal
AU - Gribar, Steven C.
AU - Kohler, Jeff W.
AU - Li, Jun
AU - Stolz, Donna Beer
AU - Sodhi, Chhinder
AU - Hackam, David J.
N1 - Funding Information:
Dr Marcucci reported receiving honoraria for lectures from Daiichi Sankyo/Eli Lilly and Merck Sharp & Dohme. Dr Gensini reported receiving consulting fees from Bayer, Boehringer Ingelheim, and Eli Lilly; lecture fees from AstraZeneca, GlaxoSmithKline, Instrumentation Laboratory, Menarini, and Sigma Tau; and research grant funding from Novo Nordisk, Merck Sharp & Dohme, Pfizer, Pierrel, sanofi-aventis, and Servier. Dr Abbate reported receiving consulting fees from Eli Lilly; lecture fees from Instrumentation Laboratory and Sigma Tau; and research grant funding from Bayer, Boehringer Ingelheim, and Pfizer.
PY - 2007
Y1 - 2007
N2 - Enterocytes exist in close association with tissue macrophages, whose activation during inflammatory processes leads to the release of nitric oxide (NO). Repair from mucosal injury requires the migration of enterocytes into the mucosal defect, a process that requires connexin43 (Cx43)-mediated gap junction communication between adjacent enterocytes. Enterocyte migration is inhibited during inflammatory conditions including necrotizing enterocolitis, in part, through impaired gap junction communication. We now hypothesize that activated macrophages inhibit gap junctions of adjacent enterocytes and seek to determine whether NO release from macrophages was involved. Using a coculture system of enterocytes and macrophages, we now demonstrate that "activation" of macrophages with lipopolysaccharide and interferon reduces the phosphorylation of Cx43 in adjacent enterocytes, an event known to inhibit gap junction communication. The effects of macrophages on enterocyte gap junctions could be reversed by treatment of macrophages with the inducible nitric oxide synthase (iNOS) inhibitor L-Lysine ω-acetamidine hydrochloride (L-NIL) and by incubation with macrophages from iNOS-/- mice, implicating NO in the process. Activated macrophages also caused a NO-dependent redistribution of connexin43 in adjacent enterocytes from the cell surface to an intracellular location, further suggesting NO release may inhibit gap junction function. Treatment of enterocytes with the NO donor S-nitroso-N-acetylpenicillamine (SNAP) markedly inhibited gap junction communication as determined using single cell microinjection of the gap junction tracer Lucifer yellow. Strikingly, activated macrophages inhibited enterocyte migration into a scraped wound, which was reversed by L-NIL pretreatment. These results implicate enterocyte gap junctions as a target of the NO-mediated effects of macrophages during intestinal inflammation, particularly where enterocyte migration is impaired.
AB - Enterocytes exist in close association with tissue macrophages, whose activation during inflammatory processes leads to the release of nitric oxide (NO). Repair from mucosal injury requires the migration of enterocytes into the mucosal defect, a process that requires connexin43 (Cx43)-mediated gap junction communication between adjacent enterocytes. Enterocyte migration is inhibited during inflammatory conditions including necrotizing enterocolitis, in part, through impaired gap junction communication. We now hypothesize that activated macrophages inhibit gap junctions of adjacent enterocytes and seek to determine whether NO release from macrophages was involved. Using a coculture system of enterocytes and macrophages, we now demonstrate that "activation" of macrophages with lipopolysaccharide and interferon reduces the phosphorylation of Cx43 in adjacent enterocytes, an event known to inhibit gap junction communication. The effects of macrophages on enterocyte gap junctions could be reversed by treatment of macrophages with the inducible nitric oxide synthase (iNOS) inhibitor L-Lysine ω-acetamidine hydrochloride (L-NIL) and by incubation with macrophages from iNOS-/- mice, implicating NO in the process. Activated macrophages also caused a NO-dependent redistribution of connexin43 in adjacent enterocytes from the cell surface to an intracellular location, further suggesting NO release may inhibit gap junction function. Treatment of enterocytes with the NO donor S-nitroso-N-acetylpenicillamine (SNAP) markedly inhibited gap junction communication as determined using single cell microinjection of the gap junction tracer Lucifer yellow. Strikingly, activated macrophages inhibited enterocyte migration into a scraped wound, which was reversed by L-NIL pretreatment. These results implicate enterocyte gap junctions as a target of the NO-mediated effects of macrophages during intestinal inflammation, particularly where enterocyte migration is impaired.
KW - Enterocyte migration
KW - Inflammation
KW - Intestinal restitution
KW - Necrotizing enterocolitis
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U2 - 10.1152/ajpgi.00331.2007
DO - 10.1152/ajpgi.00331.2007
M3 - Article
C2 - 17975131
AN - SCOPUS:38349119977
SN - 0193-1857
VL - 294
SP - G109-G119
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 1
ER -