Inducible nitric oxide synthase in duodenum of children with Giardia lamblia infection.

Mokrzycka, Małgorzata; Kolasa, Agnieszka; Wiszniewska, Barbara

doi:10.2478/v10042-008-0111-7

Cited by 17 publications

(22 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, Giardia infection on one hand immediately induces iNOS by arginine-depletion, but at the same time there are also iNOS down-regulating mechanisms in the parasite. Accordingly, iNOS expression was down-regulated in Giardia -infected calves in vivo on RNA and protein level after several weeks of infection [25,26]. …”

Section: Discussionmentioning

confidence: 99%

The role of arginine and arginine-metabolizing enzymes during Giardia – host cell interactions in vitro

et al. 2013

View full text Add to dashboard Cite

BackgroundArginine is a conditionally essential amino acid important in growing individuals and under non-homeostatic conditions/disease. Many pathogens interfere with arginine-utilization in host cells, especially nitric oxide (NO) production, by changing the expression of host enzymes involved in arginine metabolism. Here we used human intestinal epithelial cells (IEC) and three different isolates of the protozoan parasite Giardia intestinalis to investigate the role of arginine and arginine-metabolizing enzymes during intestinal protozoan infections.ResultsRNA expression analyses of major arginine-metabolizing enzymes revealed the arginine-utilizing pathways in human IECs (differentiated Caco-2 cells) grown in vitro. Most genes were constant or down-regulated (e.g. arginase 1 and 2) upon interaction with Giardia, whereas inducible NO synthase (iNOS) and ornithine decarboxylase (ODC) were up-regulated within 6 h of infection. Giardia was shown to suppress cytokine-induced iNOS expression, thus the parasite has both iNOS inducing and suppressive activities. Giardial arginine consumption suppresses NO production and the NO-degrading parasite protein flavohemoglobin is up-regulated in response to host NO. In addition, the secreted, arginine-consuming giardial enzyme arginine deiminase (GiADI) actively reduces T-cell proliferation in vitro. Interestingly, the effects on NO production and T cell proliferation could be reversed by addition of external arginine or citrulline.ConclusionsGiardia affects the host’s arginine metabolism on many different levels. Many of the effects can be reversed by addition of arginine or citrulline, which could be a beneficial supplement in oral rehydration therapy.

show abstract

Section: Discussionmentioning

confidence: 99%

The role of arginine and arginine-metabolizing enzymes during Giardia – host cell interactions in vitro

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Previous research detected a strong iNOS reactivity in the basal and apical side of enterocytes in villi epithelium, in duodenal crypts, in connective tissue cells and in the endothelial cells of lamina propria vessels in human duodenum [35] . iNOS expression in intestinal cells indicates that the isoform of the enzyme is expressed in the small intestine without inflammation.…”

Section: Discussionmentioning

confidence: 87%

The Role of Nitric Oxide in the Effects of Ovarian Steroids in the Duodenum

Yağcı¹,

Bülbül²,

Sevımlı³

et al. 2013

Kafkas Univ Vet Fak Derg

View full text Add to dashboard Cite

SummaryThe purpose of this study is to determine the distribution and expression of nNOS, eNOS and iNOS and to evaluate the role of ovarian steroids in NOS expressions in the duodenum tissues of rats. Rats in the control group (Ov group) were injected intramuscularly with sesame oil for 10 days, whereas rats in the first, second, and third experimental groups received intramuscular administration of progesterone (P group), 17β-estradiol (E2group) and 17beta-estradiol and progesterone (E2 + P group), respectively. According to the results of an immunohistochemical evaluation, a severe nNOS expression was observed in both the crypts and nerve fibers of the duodenum in the Ov, P and E2 groups but decreased in the E2 + P group. It was determined that iNOS expression increased in the surface epithelial cells and crypts of P group while it only decreased in crypts of E2 group. There was severe eNOS expression in crypts in all treatment groups, while it only increased in the surface epithelial cells in the E2 group. The results of the current experiment suggest that the effect of ovarian steroids on duodenum absorbtion and microvascular protection can be mediated by crypt and epithelial nNOS, iNOS and eNOS expressions in rats. Besides the estradiol and progesterone administration together inhibit nNOS activitiy in the duodenum. Keywords: Ovarion steroids, nNOS, iNOS, eNOS, Duodenum, Immunohistochemistry Duodenumda Ovaryum Steroidlerinin Etkisinde Nitrik Oksidin Rolü ÖzetBu çalışmanın amacı rat duodenum dokularında NOS ekspresyonları üzerinde ovaryum steroidlerinin rolünü değerlendirmek ve nNOS, eNOS ve iNOS ekspresyon ve dağılımlarını belirlemektir. Kontrol grubu ratlara (Ov grup) intramüsküler olarak 10 gün susam yağı enjekte edildi. Bunun yanında birinci, ikinci ve üçüncü deney gruplarına sırasıyla progesteron (P grup), 17β-estradiol (E2group) ve 17beta-estradiol ve progesteron (E2 + P group) uygulandı. İmmunohistokimyasal değerlendirme sonuçlarına göre, Ov, P ve E2 gruplarında duodenumun hem kriptlerinde ve hem de sinir fibrillerinde şiddetli nNOS ekspresyonu gözlendi, E2 + P grubunda ise reaksiyon şiddeti azaldı. P grubunda kriptlerde ve yüzey epitel hücrelerinde iNOS ekspresyonu artarken, E2 grubunda sadece kriptlerde reaksiyonun azaldığı belirlendi. Tüm gruplarda kriptlerde şiddetli eNOS ekspresyonu bulunurken, E2 grubunda sadece yüzey epitel hücrelerinde reaksiyon şiddetinin arttığı belirlendi. Yapılan çalışmanın sonucu, ovaryum steroidlerinin etkisinde duodenumda absorbsiyon ve mikrovasküler korumanın, sıçanlarda kript ve epitellerde nNOS, iNOS ve eNOS ekspresyonu aracılığıyla olabildiğini, bunun yanında duodenumda östrojen ve progesteronun birlikte uygulanmasının nNOS aktivitesini inhibe ettiğini göstermektedir.

show abstract

“…Trophozoites downregulate the expression of iNOS in intestinal epithelial cells . Similarly, paediatric patients infected with Giardia exhibit reduced expression of iNOS . Giardia can inhibit the production of epithelial NO by taking up and consuming arginine as a source of energy .…”

Section: Host Defence Mechanisms Against Giardia Lambliamentioning

confidence: 99%

“…Giardia can inhibit the production of epithelial NO by taking up and consuming arginine as a source of energy . As a product of this reaction, ornithine is released, which can competitively inhibit arginine uptake by the intestinal epithelium . Arginine depletion is known to induce apoptosis in human cell lines .…”

Section: Host Defence Mechanisms Against Giardia Lambliamentioning

confidence: 99%

Host defences against Giardia lamblia

Lopez-Romero

Quintero

Astiazarán-García

et al. 2015

Parasite Immunology

View full text Add to dashboard Cite

Giardia spp. is a protozoan parasite that inhabits the upper small intestine of mammals and other species and is the aetiological agent of giardiasis. It has been demonstrated that nitric oxide, mast cells and dendritic cells are the first line of defence against Giardia. IL-6 and IL-17 play an important role during infection. Several cytokines possess overlapping functions in regulating innate and adaptive immune responses. IgA and CD4(+) T cells are fundamental to the process of Giardia clearance. It has been suggested that CD4(+) T cells play a double role during the anti-Giardia immune response. First, they activate and stimulate the differentiation of B cells to generate Giardia-specific antibodies. Second, they act through a B-cell-independent mechanism that is probably mediated by Th17 cells. Several Giardia proteins that stimulate humoral and cellular immune responses have been described. Variant surface proteins, α-1 giardin, and cyst wall protein 2 can induce host protective responses to future Giardia challenges. The characterization and evaluation of the protective potential of the immunogenic proteins that are associated with Giardia will offer new insights into host-parasite interactions and may aid in the development of an effective vaccine against the parasite.

show abstract

Inducible nitric oxide synthase in duodenum of children with Giardia lamblia infection.

Cited by 17 publications

References 34 publications

The role of arginine and arginine-metabolizing enzymes during Giardia – host cell interactions in vitro

The role of arginine and arginine-metabolizing enzymes during Giardia – host cell interactions in vitro

The Role of Nitric Oxide in the Effects of Ovarian Steroids in the Duodenum

Host defences against Giardia lamblia

Contact Info

Product

Resources

About