Channelling of arginine in NO and polyamine pathways in colonocytes and consequences

Abstract

Colon epithelium is renewed within few days through asymmetric mitosis of pluripotent cells followed by differentiation and exfoliation. Absorptive colonocytes do not transport amino acids from lumen to bloodstream but import amino acids from plasma. Among amino acids, colonocytes can use L-arginine as a precursor for nitric oxide (NO) synthesis and also for polyamine synthesis through the stepwise conversion of L-arginine into L-ornithine and urea, conversion of L-ornithine into putrescine and then synthesis of spermidine and spermine. Colonic epithelial cells can transport polyamines produced exogenously by the microbiota. Polyamines are strictly necessary for undifferentiated colonic epithelial cell proliferation but NO exerts anti-proliferative effect on these cells raising the view that the channelling of arginine in the nitric oxide and polyamine pathways is involved in the control of cellular proliferation. Furthermore, NO has been shown to be a potent inhibitor of ornithine decarboxylase activity in colonic epithelial cells. Unbalance of the chanelling of arginine in the NO and polyamine pathways in colonic cancerous epithelial cells as a determinant promoting their proliferation is discussed.

Analysis of gene–environment interactions in postnatal development of the mammalian intestine

“…In addition to being used for polypeptide synthesis, amino acids also play a critical role as precursors for the synthesis of polyamines, glutathione, and nitric oxide, as well as signaling molecules and key regulators of various intestinal physiological functions, such as differentiation, barrier function, and inflammation (20)(21)(22). However, little is known about the regulation of amino acid metabolism and transport at different postnatal states.…”

Dietary l-arginine supplementation enhances placental growth and reproductive performance in sows

“…Arginine, which is an unusually abundant amino acid in the conceptus, (Wu 2009) is utilized by multiple pathways, including the synthesis of protein, nitric oxide (NO), polyamines, and creatine (Blachier et al 2011;Wu and Morris 1998;Wu et al 2007Wu et al , 2009. Several studies have demonstrated that polyamines and NO are essential to placental growth and angiogenesis, therefore increasing uterine and placental-fetal blood flow (Gardner et al 2001;McCrabb and Harding 1996;Wu et al 2006).…”

Functional amino acids in nutrition and health

“…Amino acids (AA) are building blocks for tissue proteins and essential substrates for the synthesis of many lowmolecular-weight substances (e.g., NO, polyamines, glutathione, creatine, carnitine, carnosine, thyroid hormones, serotonin, melanin, melatonin, and heme) with enormous physiological importance (Blachier et al 2011;Kim et al 2012;Kong et al 2012;Wu 2009). Based on the growth or nitrogen balance of animals, AA have been traditionally classified as nutritionally ''essential'' or ''nonessential'' (see Wu 2009 for review).…”