Gastrointestinal luminal polyamines: cellular accumulation and enterohepatic circulation

Osborne, David; Seidel, Edward R.

doi:10.1152/ajpgi.1990.258.4.g576

Cited by 66 publications

(58 citation statements)

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“…The polyamine levels observed in the pigs' intestine are closer in range than those previously reported in rats [16,21] and in healthy humans [3]. In rats, the highest lumenal concentrations of polyamines were observed in the jejunum, indicating a polyamine supply in the upper part of the intestine and subsequent absorption along the intestine from the jejunum to the ileum [21]. This pattern was not observed in the present study.…”

Section: Lumenal Polyaminessupporting

confidence: 70%

Effects of soy protein diet on digestive lumenal polyamines and colonic cell proliferation in pigs

Bénamouzig¹,

Mahé²,

Meziani³

et al. 1999

Reprod. Nutr. Dev.

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-This study was performed to determine whether erythrocyte and digestive lumenal polyamine concentrations are affected by a soy protein diet when compared to a casein diet. We also determined the effects of these diets on colonic cell proliferation. Sixteen pigs received either a 16 % soy protein or casein diet for 25 days. The erythrocyte putrescine was higher in pigs fed the soy protein diet. Significant levels of polyamines were observed in the digestive lumen on both diets. Lumenal putrescine and cadaverine were higher in the proximal colon in the casein group. Lumenal spermidine was higher in the caecum and colon in the soy protein group. No significant differences in the ornithine decarboxylase activity nor in the proliferative cell nuclear antigen labelling index were observed in the colonic mucosa regardless of the regimen. These

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Section: Lumenal Polyaminessupporting

confidence: 70%

Effects of soy protein diet on digestive lumenal polyamines and colonic cell proliferation in pigs

Bénamouzig¹,

Mahé²,

Meziani³

et al. 1999

Reprod. Nutr. Dev.

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“…Increasing evidence indicates that the natural polyamines spermidine and spermine and their precursor, putrescine, are the central convergence point for the multiple signaling pathways driving different epithelial cell functions. We (8 -10) and others (11,12) have shown that normal intestinal epithelial growth depends on the supply of polyamines to the dividing cells in the crypts, and that differentiated epithelial cells of the mucosal surface are also exposed to the high concentrations of polyamines in the luminal contents of the intestine (13). Recently, polyamines have been implicated in the control of the apoptotic response in intestinal epithelial cells (14 -16).…”

mentioning

confidence: 99%

Akt Kinase Activation Blocks Apoptosis in Intestinal Epithelial Cells by Inhibiting Caspase-3 after Polyamine Depletion

Zhang

Rao

Guo

et al. 2004

Journal of Biological Chemistry

103

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Apoptosis plays a critical role in the maintenance of gut mucosal homeostasis and is regulated by numerous factors including polyamines. Although the exact roles of polyamines in apoptotic pathway are still unclear, inhibition of polyamine synthesis promotes the resistance of intestinal epithelial cells to apoptosis. Akt is a serine-threonine kinase that has been established as an important intracellular signaling in regulating cell survival. The current studies test the hypothesis that polyamines are involved in the control of Akt activity in normal intestinal epithelial cells (IEC-6 line) and that activated Akt mediates suppression of apoptosis following polyamine depletion. Depletion of cellular polyamines by ␣-difluoromethylornithine induced levels of phosphorylated Akt and increased Akt kinase activity, although it had no effect on expression of total Akt, pERK, p38, and Bcl-2 proteins. This activated Akt was associated with both decreased levels of active caspase-3 and increased resistance to tumor necrosis factor-␣/cycloheximide-induced apoptosis. Inactivation of Akt by either treatment with LY294002 or ectopic expression of a dominant negative Akt mutant (DNMAkt) not only enhanced the caspase-3 activation in polyamine-deficient cells but also prevented the increased resistance to tumor necrosis factor-␣/cycloheximide-induced apoptosis. Phosphorylation of glycogen synthase kinase-3, a downstream target of Akt, was also increased in ␣-difluoromethylornithine-treated cells, which was prevented by inactivation of Akt by LY294002 or DNMAkt overexpression. These results indicate that polyamine depletion induces the Akt activation mediating suppression of apoptosis via inhibition of caspase-3 in normal intestinal epithelial cells.

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“…Polyamines may also increase the virulence potential of UPEC by modifying biofilm formation, affecting the conductivity of outer membrane porins, and/or altering the expression of secreted toxins and iron-chelating agents (51,56). Notably, polyamines are abundant within the intestinal tract (13,46) and can also be found in substantial quantities within vaginal secretions (9,34), where they may interact with and phenotypically modulate UPEC prior to entry into the urinary tract. UPEC may also encounter high levels of polyamines within the urinary tract, where urine polyamine concentrations can be elevated as a consequence of pregnancy or UTI (1,55).…”

Section: Discussionmentioning

confidence: 99%

Conditioning of Uropathogenic Escherichia coli for Enhanced Colonization of Host

2009

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While in transit within and between hosts, uropathogenic Escherichia coli (UPEC) encounters multiple stresses, including substantial levels of nitric oxide and reactive nitrogen intermediates. Here we show that UPEC, the primary cause of urinary tract infections, can be conditioned to grow at higher rates in the presence of acidified sodium nitrite (ASN), a model system used to generate nitrosative stress. When inoculated into the bladder of a mouse, ASN-conditioned UPEC bacteria are far more likely to establish an infection than nonconditioned bacteria. Microarray analysis of ASN-conditioned bacteria suggests that several NsrR-regulated genes and other stress-and polyamine-responsive factors may be partially responsible for this effect. Compared to K-12 reference strains, most UPEC isolates have increased resistance to ASN, and this resistance can be substantially enhanced by addition of the polyamine cadaverine. Nitrosative stress, as generated by ASN, can stimulate cadaverine synthesis by UPEC, and growth of UPEC in cadaverine-supplemented broth in the absence of ASN can also promote UPEC colonization of the bladder. These results suggest that UPEC interactions with polyamines or stresses such as reactive nitrogen intermediates can in effect reprogram the bacteria, enabling them to better colonize the host.The urinary tract is normally a sterile environment, and it is both hostile and poorly accessible to most microbes. However, roughly one-half of women in the United States experience a urinary tract infection (UTI) at least once in their lifetime, and one-quarter of affected women endure recurrence (22,25). More than 80% of UTIs are due to strains of uropathogenic Escherichia coli (UPEC), which are usually presumed to be part-time gut flora that have reached the urinary tract by ascension via the periurethral area (53). Transmission of UPEC among individuals occurs primarily by way of fecal-oral routes and, in some cases, may involve the ingestion of contaminated food products or sexual contact (15,23,33,40,41,57). In order to survive and disseminate, UPEC must be able to adapt to multiple environments and stresses both within and outside the host.When a UPEC infection occurs, recruitment of nitric oxide (NO)-producing neutrophils to the bladder is an important line of defense (26,48). Within hours of infection, the nitrite levels in the urine increase up to threefold, and eventually the levels of NO within the bladder are 30-to 50-fold higher than those in uninfected controls (39, 48). The high levels of NO are due in part to inducible NO synthase activity, which is upregulated within 6 h after infection (45). A role may also be played by endothelial NO synthase, which is upregulated and activated in the bladder mucosa by E. coli lipopolysaccharide (36) and by the bacteria themselves, which can produce NO with nitrite reductases under low-oxygen-tension conditions (12). NO is a precursor of a variety of reactive nitrogen intermediates (RNIs), such as peroxynitrite and nitrosothiols, which can inflict exten...

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Gastrointestinal luminal polyamines: cellular accumulation and enterohepatic circulation

Cited by 66 publications

References 0 publications

Effects of soy protein diet on digestive lumenal polyamines and colonic cell proliferation in pigs

Effects of soy protein diet on digestive lumenal polyamines and colonic cell proliferation in pigs

Akt Kinase Activation Blocks Apoptosis in Intestinal Epithelial Cells by Inhibiting Caspase-3 after Polyamine Depletion

Conditioning of Uropathogenic Escherichia coli for Enhanced Colonization of Host

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