PRRSV is capable of evading the effective immune response, thus persisting in piglets and throughout the swine herd. We show here that PRRSV invades the thymus and causes depletion of T-cell precursors and alteration of the TCR repertoire. Developing thymocytes are affected during negative selection when they transit from the triple-negative to triple-positive stages at the corticomedullary junction just before entering the medulla. The restriction of repertoire diversification occurs in both helper and cytotoxic αβ-T cells. As a result, critical viral epitopes are tolerated, and infection becomes chronic. However, not all viral epitopes are tolerated. Infected piglets develop antibodies capable of recognizing PRRSV, but these are not virus neutralizing. Further analysis showed that the lack of an effective immune response against the critical viral structures results in the absence of a germinal center response, overactivation of T and B cells in the periphery, robust production of useless antibodies of all isotypes, and the inability to eliminate the virus. Overall, the results show how a respiratory virus that primarily infects and destroys myelomonocytic cells has evolved strategies to disrupt the immune system. These mechanisms may be a prototype for how other viruses can similarly modulate the host immune system.

• Klíčová slova
• Animals, Lymhocytes, Porcine respiratory and reproductive syndrome virus, T-cell precursors, Thymocytes,
• MeSH
• B-lymfocyty MeSH
• epitopy MeSH
• prasata MeSH
• protilátky virové MeSH
• reprodukční a respirační syndrom prasat * MeSH
• virus reprodukčního a respiračního syndromu prasat * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• epitopy MeSH
• protilátky virové MeSH

INTRODUCTION: Porcine reproductive and respiratory syndrome virus (PRRSV) emerged about 30 years ago and continues to cause major economic losses in the pork industry. The lack of effective modified live vaccines (MLV) allows the pandemic to continue. BACKGROUND AND OBJECTIVE: We have previously shown that wild strains of PRRSV affect the nascent T cell repertoire in the thymus, deplete T cell clones recognizing viral epitopes essential for neutralization, while triggering a chronic, robust, but ineffective antibody response. Therefore, we hypothesized that the current MLV are inappropriate because they cause similar damage and fail to prevent viral-induced dysregulation of adaptive immunity. METHODS: We tested three MLV strains to demonstrate that all have a comparable negative effect on thymocytes in vitro. Further in vivo studies compared the development of T cells in the thymus, peripheral lymphocytes, and antibody production in young piglets. These three MLV strains were used in a mixture to determine whether at least some of them behave similarly to the wild virus type 1 or type 2. RESULTS: Both the wild and MLV strains cause the same immune dysregulations. These include depletion of T-cell precursors, alteration of the TCR repertoire, necrobiosis at corticomedullary junctions, low body weight gain, decreased thymic cellularity, lack of virus-neutralizing antibodies, and production of non-neutralizing anti-PRRSV antibodies of different isotypes. DISCUSSION AND CONCLUSION: The results may explain why the use of current MLV in young animals may be ineffective and why their use may be potentially dangerous. Therefore, alternative vaccines, such as subunit or mRNA vaccines or improved MLV, are needed to control the PRRSV pandemic.

• Klíčová slova
• B lymphocytes, Porcine respiratory and reproductive syndrome virus, T lymphocytes, T-cell precursors, animals, thymocytes,
• MeSH
• atenuované vakcíny MeSH
• imunitní systém MeSH
• prasata MeSH
• protilátky virové MeSH
• reprodukční a respirační syndrom prasat * prevence a kontrola   MeSH
• virus reprodukčního a respiračního syndromu prasat * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• atenuované vakcíny MeSH
• protilátky virové MeSH

Microbiome is now considered as a significant metabolic organ with an immense potential to influence overall human health. A number of diseases that are associated with pharmacotherapy interventions was linked with altered gut microbiota. Moreover, it has been reported earlier that gut microbiome modulates the fate of more than 30 commonly used drugs and, vice versa, drugs have been shown to affect the composition of the gut microbiome. The molecular mechanisms of this mutual relationship, however, remain mostly elusive. Recent studies indicate an indirect effect of the gut microbiome through its metabolites on the expression of biotransformation enzymes in the liver. The aim of this study was to analyse the effect of gut microbiome on the fate of metronidazole in the mice through modulation of system of drug metabolizing enzymes, namely by alteration of the expression and activity of selected cytochromes P450 (CYPs). To assess the influence of gut microbiome, germ-free mice (GF) in comparison to control specific-pathogen-free (SPF) mice were used. First, it has been found that the absence of microbiota significantly affected plasma concentration of metronidazole, resulting in higher levels (by 30%) of the parent drug in murine plasma of GF mice. Further, the significant interaction between presence/absence of the gut microbiome and effect of metronidazole application, which together influence mRNA expression of CAR, PPARα, Cyp2b10 and Cyp2c38 was determined. Administration of metronidazole itself influenced significantly mRNA expression of Cyp1a2, Cyp2b10, Cyp2c38 and Cyp2d22. Finally, GF mice have shown lower level of enzyme activity of CYP2A and CYP3A than their SPF counterparts. The results hence have shown that, beside direct bacterial metabolism, different expression and enzyme activity of hepatic CYPs in the presence/absence of gut microbiota may be responsible for the altered metronidazole metabolism.

• MeSH
• játra MeSH
• metronidazol MeSH
• myši MeSH
• střevní mikroflóra * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• metronidazol MeSH

The classical definition of probiotics states that bacteria must be alive to be beneficial for human organism. However, recent reports show that inactivated bacteria or their effector molecules can also possess such properties. In this study, we investigated the physical and immunomodulatory properties of four Bifidobacterium strains in the heat-treated (HT) and untreated (UN) forms. We showed that temperature treatment of bacteria changes their size and charge, which affects their interaction with epithelial and immune cells. Based on the in vitro assays, we observed that all tested strains reduced the level of OVA-induced IL-4, IL-5, and IL-13 in the spleen culture of OVA-sensitized mice. We selected Bifidobacterium longum ssp. longum CCM 7952 (Bl 7952) for further analysis. In vivo experiments confirmed that untreated Bl 7952 exhibited allergy-reducing properties when administered intranasally to OVA-sensitized mice, which manifested in significant suppression of airway inflammation. Untreated Bl 7952 decreased local and systemic levels of Th2 related cytokines, OVA-specific IgE antibodies and simultaneously inhibited airway eosinophilia. In contrast, heat-treated Bl 7952 was only able to reduce IL-4 levels in the lungs and eosinophils in bronchoalveolar lavage, but increased neutrophil and macrophage numbers. We demonstrated that the viability status of Bl 7952 is a prerequisite for the beneficial effects of bacteria, and that heat treatment reduces but does not completely abolish these properties. Further research on bacterial effector molecules to elucidate the beneficial effects of probiotics in the prevention of allergic diseases is warranted.

• Klíčová slova
• Bifidobacterium, Ovalbumin sensitization, allergy, heat inactivation, intranasal administration, probiotic,
• MeSH
• alergie * MeSH
• Bifidobacterium * MeSH
• modely nemocí na zvířatech MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• probiotika * MeSH
• viabilita buněk * MeSH
• zánět * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Glucocorticoids (GCs) are hormones that are released in response to stressors and exhibit many activities, including immunomodulatory and anti-inflammatory activities. They are primarily synthesized in the adrenal gland but are also produced in peripheral tissues via regeneration of adrenal 11-oxo metabolites or by de novo synthesis from cholesterol. The present study investigated the influence of the microbiota on de novo steroidogenesis and regeneration of corticosterone in the intestine of germ-free (GF) and specific pathogen-free mice challenged with a physical stressor (anti-CD3 antibody i.p. injection). In the small intestine, acute immune stress resulted in increased mRNA levels of the proinflammatory cytokines IL1β, IL6 and Tnfα and genes involved in de novo steroidogenesis (Stard3 and Cyp11a1), as well as in regeneration of active GCs from their 11-oxo metabolites (Hsd11b1). GF mice showed a generally reduced transcriptional response to immune stress, which was accompanied by decreased intestinal corticosterone production and reduced expression of the GC-sensitive marker Fkbp5. In contrast, the interaction between stress and the microbiota was not detected at the level of plasma corticosterone or the transcriptional response of adrenal steroidogenic enzymes. The results indicate a differential immune stress-induced intestinal response to proinflammatory stimuli and local corticosterone production driven by the gut microbiota.

• Klíčová slova
• 11β-hydroxysteroid dehydrogenase, anti-CD3 antibody, extra-adrenal steroidogenesis, glucocorticoids, intestine, microbiome,
• MeSH
• 11-beta-hydroxysteroid dehydrogenasy genetika   metabolismus   MeSH
• kortikosteron metabolismus   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• myši MeSH
• steroidy metabolismus   MeSH
• střevní mikroflóra fyziologie   MeSH
• tandemová hmotnostní spektrometrie MeSH
• tenké střevo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 11-beta-hydroxysteroid dehydrogenasy MeSH
• kortikosteron MeSH
• steroidy MeSH

Mucosal surfaces are colonized by highly diverse commensal microbiota. Coating with secretory IgA (SIgA) promotes the survival of commensal bacteria while it inhibits the invasion by pathogens. Bacterial coating could be mediated by antigen-specific SIgA recognition, polyreactivity, and/or by the SIgA-associated glycans. In contrast to many in vitro studies, only a few reported the effect of SIgA glycans in vivo. Here, we used a germ-free antibody-free newborn piglets model to compare the protective effect of SIgA, SIgA with enzymatically removed N-glycans, Fab, and Fc containing the secretory component (Fc-SC) during oral necrotoxigenic E. coli O55 challenge. SIgA, Fab, and Fc-SC were protective, whereas removal of N-glycans from SIgA reduced SIgA-mediated protection as demonstrated by piglets' intestinal histology, clinical status, and survival. In vitro analyses indicated that deglycosylation of SIgA did not reduce agglutination of E. coli O55. These findings highlight the role of SIgA-associated N-glycans in protection. Further structural studies of SIgA-associated glycans would lead to the identification of those involved in the species-specific inhibition of attachment to corresponding epithelial cells.

• MeSH
• aglutinace MeSH
• Escherichia coli fyziologie   MeSH
• glykosylace MeSH
• gnotobiologické modely MeSH
• imunoglobulin A sekreční metabolismus   MeSH
• imunoglobuliny - Fab fragmenty metabolismus   MeSH
• infekce vyvolané Escherichia coli imunologie   MeSH
• jednořetězcové protilátky metabolismus   MeSH
• novorozená zvířata MeSH
• odolnost vůči nemocem MeSH
• polysacharidy metabolismus   MeSH
• prasata MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• imunoglobulin A sekreční MeSH
• imunoglobuliny - Fab fragmenty MeSH
• jednořetězcové protilátky MeSH
• polysacharidy MeSH

Sexual differences and the composition/function of the gut microbiome are not considered the most important players in the drug metabolism field; however, from the recent data it is obvious that they may significantly affect the response of the patient to therapy. Here, we evaluated the effect of microbial colonization and sex differences on mRNA expression and the enzymatic activity of hepatic cytochromes P450 (CYPs) in germ-free (GF) mice, lacking the intestinal flora, and control specific-pathogen-free (SPF) mice. We observed a significant increase in the expression of Cyp3a11 in female SPF mice compared to the male group. However, the sex differences were erased in GF mice, and the expression of Cyp3a11 was about the same in both sexes. We have also found higher Cyp2c38 gene expression in female mice compared to male mice in both the SPF and GF groups. Moreover, these changes were confirmed at the level of enzymatic activity, where the female mice exhibit higher levels of functional CYP2C than males in both groups. Interestingly, we observed the same trend as with CYP3A enzymes: a diminished difference between the sexes in GF mice. The presented data indicate that the mouse gut microbiome plays an important role in sustaining sexual dimorphism in terms of hepatic gene expression and metabolism.

• Klíčová slova
• germ-free mice, gut microbiome, liver cytochromes P450, metabolism of drugs, sex difference,
• Publikační typ
• časopisecké články MeSH

The gut microbiota is involved in a number of different metabolic processes of the host organism, including the metabolism of xenobiotics. In our study, we focused on liver cytochromes P450 (CYPs), which can metabolize a wide range of exo- and endogenous molecules. We studied changes in mRNA expression and CYP enzyme activities, as well as the mRNA expression of transcription factors that have an important role in CYP expression, all in stressed germ-free (GF) and stressed specific-pathogen-free (SPF) mice. Besides the presence of the gut microbiota, we looked at the difference between acute and chronic stress. Our results show that stress has an impact on CYP mRNA expression, but it is mainly chronic stress that has a significant effect on enzyme activities along with the gut microbiome. In acutely stressed mice, we observed significant changes at the mRNA level, however, the corresponding enzyme activities were not influenced. Our study suggests an important role of the gut microbiota along with chronic psychosocial stress in the expression and activity of CYPs, which can potentially lead to less effective drug metabolism and, as a result, a harmful impact on the organism.

• MeSH
• játra enzymologie   mikrobiologie   MeSH
• messenger RNA genetika   metabolismus   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• psychický stres * MeSH
• regulace genové exprese enzymů MeSH
• střevní mikroflóra fyziologie   MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• transkripční faktory genetika   metabolismus   MeSH
• xenobiotika metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• messenger RNA MeSH
• systém (enzymů) cytochromů P-450 MeSH
• transkripční faktory MeSH
• xenobiotika MeSH

The gut microbiota play an important role in shaping brain functions and behavior, including the activity of the hypothalamus-pituitary-adrenocortical (HPA) axis. However, little is known about the effect of the microbiota on the distinct structures (hypothalamus, pituitary, and adrenals) of the HPA axis. In the present study, we analyzed the influence of the microbiota on acute restraint stress (ARS) response in the pituitary, adrenal gland, and intestine, an organ of extra-adrenal glucocorticoid synthesis. Using specific pathogen-free (SPF) and germ-free (GF) male BALB/c mice, we showed that the plasma corticosterone response to ARS was higher in GF than in SPF mice. In the pituitary, stress downregulated the expression of the gene encoding CRH receptor type 1 (Crhr1), upregulated the expression of the Fkbp5 gene regulating glucocorticoid receptor sensitivity and did not affect the expression of the proopiomelanocortin (Pomc) and glucocorticoid receptor (Gr) genes. In contrast, the microbiota downregulated the expression of pituitary Pomc and Crhr1 but had no effect on Fkbp5 and Gr. In the adrenals, the steroidogenic pathway was strongly stimulated by ARS at the level of the steroidogenic transcriptional regulator Sf-1, cholesterol transporter Star and Cyp11a1, the first enzyme of steroidogenic pathway. In contrast, the effect of the microbiota was significantly detected at the level of genes encoding steroidogenic enzymes but not at the level of Sf-1 and Star. Unlike adrenal Sf-1, the expression of the gene Lrh-1, which encodes the crucial transcriptional regulator of intestinal steroidogenesis, was modulated by the microbiota and ARS and this effect differed between the ileum and colon. The findings demonstrate that gut microbiota have an impact on the response of the pituitary, adrenals and intestine to ARS and that the interaction between stress and the microbiota during activation of glucocorticoid steroidogenesis differs between organs. The results suggest that downregulated expression of pituitary Pomc and Crhr1 in SPF animals might be an important factor in the exaggerated HPA response of GF mice to stress.

• Klíčová slova
• HPA axis, acute restraint stress, extra-adrenal glucocorticoid synthesis, germ-free, gut microbiota, intestine, mice,
• MeSH
• enzym štěpící postranní řetězce cholesterolu genetika   MeSH
• fosfoproteiny genetika   MeSH
• fyzické omezení * MeSH
• hypofýza metabolismus   MeSH
• ileum metabolismus   mikrobiologie   MeSH
• kolon metabolismus   mikrobiologie   MeSH
• kortikosteron krev   MeSH
• myši inbrední BALB C MeSH
• nadledviny metabolismus   MeSH
• pro-opiomelanokortin genetika   MeSH
• psychický stres krev   mikrobiologie   MeSH
• receptory hormonu uvolňujícího kortikotropin genetika   MeSH
• regulace genové exprese MeSH
• steroidogenní faktor 1 genetika   MeSH
• střevní mikroflóra * MeSH
• systém hypofýza - nadledviny * MeSH
• systém hypotalamus-hypofýza * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CRF receptor type 1 MeSH Prohlížeč
• enzym štěpící postranní řetězce cholesterolu MeSH
• fosfoproteiny MeSH
• kortikosteron MeSH
• pro-opiomelanokortin MeSH
• receptory hormonu uvolňujícího kortikotropin MeSH
• steroidogenic acute regulatory protein MeSH Prohlížeč
• steroidogenní faktor 1 MeSH

1. The underlying microbial metabolic activity toward xenobiotics is among the least explored factors contributing to the inter-individual variability in drug response. 2. Here, we analyzed the effect of microbiota on a non-steroidal anti-inflammatory drug nabumetone. 3. First, we cultivated the drug with the selected gut commensal and probiotic bacteria under both aerobic and anaerobic conditions and analyzed its metabolites by high-performance liquid chromatography (HPLC) with UV detection. To analyze the effect of microbiota on nabumetone pharmacokinetics in vivo, we administered a single oral dose of nabumetone to rodents with intentionally altered gut microbiome - either rats treated for three days with the antibiotic imipenem or to germ-free mice. Plasma levels of its main active metabolite 6 methoxy-2-naphthylacetic acid (6-MNA) were analyzed at pre-specified time intervals using HPLC with UV/fluorescence detection. 4. We found that nabumetone is metabolized by bacteria to its non-active metabolites and that this effect is stronger under anaerobic conditions. Although in vivo, none of the pharmacokinetic parameters of 6-MNA was significantly altered, there was a clear trend towards an increase of the AUC, Cmax and t1/2 in rats with reduced microbiota and germ-free mice.

• Klíčová slova
• Gut microbiome, bioavailability, germ-free mice, imipenem, metabolism of drugs, pharmacokinetic of nabumetone,
• MeSH
• anaerobióza MeSH
• antibakteriální látky farmakologie   MeSH
• antiflogistika nesteroidní metabolismus   farmakokinetika   MeSH
• biologická dostupnost MeSH
• imipenem farmakologie   MeSH
• kyseliny naftalenoctové metabolismus   farmakokinetika   MeSH
• myši inbrední BALB C MeSH
• nabumeton metabolismus   farmakokinetika   MeSH
• organismy bez specifických patogenů MeSH
• potkani Wistar MeSH
• střevní mikroflóra účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• audiovizuální média MeSH
• časopisecké články MeSH
• Názvy látek
• 6-methoxy-2-naphthylacetic acid MeSH Prohlížeč
• antibakteriální látky MeSH
• antiflogistika nesteroidní MeSH
• imipenem MeSH
• kyseliny naftalenoctové MeSH
• nabumeton MeSH