TY - JOUR
T1 - L-Arginine supplementation prevents intestinal epithelial barrier breakdown under heat stress conditions by promoting nitric oxide synthesis
AU - Varasteh, Soheil
AU - Braber, Saskia
AU - Kraneveld, Aletta D.
AU - Garssen, Johan
AU - Fink-Gremmels, Johanna
PY - 2018/9/1
Y1 - 2018/9/1
N2 - Heat stress (HS) induced by exposure to high ambient temperatures or prolonged excessive physical activities is known to primarily induce deleterious effects on the intestinal integrity by disrupting junctional complexes. Considering the association of L-arginine (L-Arg) with the improvement of gut function, the hypothesis of this study was to assess whether L-Arg supplementation can prevent the intestinal barrier disruption under HS conditions and to understand whether the L-Arg–induced effects are associated with maintaining nitric oxide (NO) as the major product of L-Arg metabolism. For this study, human colorectal adenocarcinoma (Caco-2) cells grown on Transwell inserts were pretreated with different L-Arg concentrations (0.4, 1, and 4 mmol/L), and after exposure to HS, markers of intestinal barrier integrity, stress-related markers, and NO levels were determined. L-Arg deprivation markedly increased the mRNA expression of heat shock protein 70 and heme-oxygenase-1 under HS conditions. The HS-induced drop in transepithelial electrical resistance values and increase in Lucifer Yellow permeability could be prevented by 4 mmol/L L-Arg supplementation. In turn, L-Arg mitigated the downregulation and delocalization of adherens junction protein E-cadherin in HS-exposed cells. NO and inducible NO synthase levels were significantly decreased in HS-exposed cells, whereas pretreatment with 4 mmol/L L-Arg prevented this decrease. Inhibition of inducible NO synthase by the NO synthase inhibitor L-NG-nitroarginine methyl ester abrogated the effect of L-Arg on preserving intestinal integrity under HS conditions as measured by transepithelial electrical resistance, Lucifer Yellow flux, and E-cadherin expression. In summary, L-Arg supplementation protects the intestinal epithelial integrity, at least partly, by maintaining NO synthesis under HS conditions.
AB - Heat stress (HS) induced by exposure to high ambient temperatures or prolonged excessive physical activities is known to primarily induce deleterious effects on the intestinal integrity by disrupting junctional complexes. Considering the association of L-arginine (L-Arg) with the improvement of gut function, the hypothesis of this study was to assess whether L-Arg supplementation can prevent the intestinal barrier disruption under HS conditions and to understand whether the L-Arg–induced effects are associated with maintaining nitric oxide (NO) as the major product of L-Arg metabolism. For this study, human colorectal adenocarcinoma (Caco-2) cells grown on Transwell inserts were pretreated with different L-Arg concentrations (0.4, 1, and 4 mmol/L), and after exposure to HS, markers of intestinal barrier integrity, stress-related markers, and NO levels were determined. L-Arg deprivation markedly increased the mRNA expression of heat shock protein 70 and heme-oxygenase-1 under HS conditions. The HS-induced drop in transepithelial electrical resistance values and increase in Lucifer Yellow permeability could be prevented by 4 mmol/L L-Arg supplementation. In turn, L-Arg mitigated the downregulation and delocalization of adherens junction protein E-cadherin in HS-exposed cells. NO and inducible NO synthase levels were significantly decreased in HS-exposed cells, whereas pretreatment with 4 mmol/L L-Arg prevented this decrease. Inhibition of inducible NO synthase by the NO synthase inhibitor L-NG-nitroarginine methyl ester abrogated the effect of L-Arg on preserving intestinal integrity under HS conditions as measured by transepithelial electrical resistance, Lucifer Yellow flux, and E-cadherin expression. In summary, L-Arg supplementation protects the intestinal epithelial integrity, at least partly, by maintaining NO synthesis under HS conditions.
KW - E-cadherin
KW - Heat stress
KW - Inducible nitric oxide synthase
KW - Intestinal barrier integrity
KW - L-Arginine
KW - Nitric oxide
UR - http://www.scopus.com/inward/record.url?scp=85049347718&partnerID=8YFLogxK
U2 - 10.1016/j.nutres.2018.05.007
DO - 10.1016/j.nutres.2018.05.007
M3 - Article
AN - SCOPUS:85049347718
SN - 0271-5317
VL - 57
SP - 45
EP - 55
JO - Nutrition Research
JF - Nutrition Research
ER -