ex-vivo-intestinal-sacs-to-assess-mucosal-permeability-models

<em>Ex Vivo</em> Intestinal Sacs to Assess Mucosal Permeability in Models of Gastrointestinal Disease

The epithelial barrier is the first innate defense of the gastrointestinal tract and selectively regulates transport from the lumen to the underlying ...

In this study, we collected and analyzed the first data available on the extent of the adoption of safer needle devices (engineered sharps injury protections [ESIPs]) by U.S. hospitals and on the degree to which selected factors influence the use of this technology.

Prevalence of safer needle devices and factors associated with their adoption: results of a national hospital survey.

Th1 cells and gamma interferon (IFN-gamma) production play critical roles in protective immunity against genital tract infections by Chlamydia trachomatis. Here we show that inducible costimulatory molecule (ICOS)(-/-) mice develop greatly augmented host resistance against chlamydial infection. Protection following a primary infection was characterized by strong Th1 immunity with enhanced CD4(+) T-cell-mediated IFN-gamma production in the genital tract and high expression of T-bet in the draining para-aortic lymph node. This Th1 dominance was associated with low expression of interleukin 10 (IL-10) mRNA in the uteruses of protected ICOS(-/-) mice. By contrast, CD28(-/-) mice were severely impaired in their adaptive immune response, demonstrating a lack of CD4(+) T cells and IFN-gamma in the genital tract, with a substantial delay in bacterial elimination compared to that seen in wild-type (WT) mice. Upon reinfection, WT mice exhibited a transient local infection with evidence of regulatory T-cell (Treg)/Foxp3 mRNA and a more balanced Th1 and Th2 response in the genital tract than ICOS(-/-) mice, whereas 90% of the latter mice developed sterile immunity, poor expression of local Treg/Foxp3 mRNA, and macroscopic signs of enhanced local immunopathology. Therefore, different requirements for CD28 signaling and ICOS signaling clearly apply to host protection against a genital tract infection by C. trachomatis. Whereas, CD28 signaling is critical, ICOS appears to be dispensable and can have a dampening effect on Th1 development by driving Th2 immunity and anti-inflammation through IL-10 production and promotion of the Foxp3(+) Treg populations in the genital tract. Both the CD28-deficient and the ICOS-deficient mice demonstrated poor specific antibody production, supporting the fact that antibodies are not needed for protection against genital tract chlamydial infections.

Differential CD28 and inducible costimulatory molecule signaling requirements for protective CD4+ T-cell-mediated immunity against genital tract Chlamydia trachomatis infection.

Collaboration addresses information and education needs of an urban public health workforce.

The purpose of this study was to identify and describe published research articles that were named in official findings of scientific misconduct and to investigate compliance with the administrative actions contained in these reports for corrections and retractions, as represented in PubMed. Between 1993 and 2001, 102 articles were named in either the NIH Guide for Grants and Contracts ("Findings of Scientific Misconduct") or the U.S. Office of Research Integrity annual reports as needing retraction or correction. In 2002, 98 of the 102 articles were indexed in PubMed. Eighty-five of these 98 articles had indexed corrections: 47 were retracted; 26 had an erratum; 12 had a correction described in the "comment" field. Thirteen had no correction, but 10 were linked to the NIH Guide "Findings of Scientific Misconduct", leaving only 3 articles with no indication of any sort of problem. As of May 2005, there were 5,393 citations to the 102 articles, with a median of 26 citations per article (range 0-592). Researchers should be alert to "Comments" linked to the NIH Guide as these are open access, and the "Findings of Scientific Misconduct' reports are often more informative than the statements about the retraction or correction found in the journals.

Correction and use of biomedical literature affected by scientific misconduct.

While a primary genital tract infection with C. trachomatis stimulates partial-protection against re-infection, it may also result in severe inflammation and tissue destruction. Here we have dissected whether functional compartments exist in the genital tract that restrict Th1-mediated protective immunity. Apart from the Th1-subset, little is known about the role of other CD4(+) T cell subsets in response to a genital tract chlamydial infection. Therefore, we investigated CD4(+) T cell subset differentiation in the genital tract using RT-PCR for expression of critical transcription factors and cytokines in the upper (UGT) and lower genital tract (LGT) of female C57BL/6 mice in response to C. trachomatis serovar D infection. We found that the Th1 subset dominated the UGT, as IFN-γ and T-bet mRNA expression were high, while GATA-3 was low following genital infection with C. trachomatis serovar D. By contrast, IL-10 and GATA-3 mRNA dominated the LGT, suggesting the presence of Th2 cells. These functional compartments also attracted regulatory T cells (Tregs) differently as increased FoxP3 mRNA expression was seen primarily in the UGT. Although IL-17A mRNA was somewhat up-regulated in the LGT, no significant change in RORγ-t mRNA expression was observed, suggesting no involvement of Th17 cells. The dichotomy between the LGT and UGT was maintained during infection by IL-10 because in IL-10-deficient mice the distinction between the two compartments was completely lost and a dramatic shift to the predominance of Th1 cells in the LGT occurred. Unexpectedly, the major source of IL-10 was CD11c(+) CD11b(+) DC, probably creating an anti-inflammatory privileged site in the LGT.

The female lower genital tract is a privileged compartment with IL-10 producing dendritic cells and poor Th1 immunity following Chlamydia trachomatis infection.

Immunizations via the i.n. and intravaginal (ivag) routes effectively generate strong genital tract antibody-mediated immunity. To what extent the same is true for T-cell responses is incompletely known. Therefore, we set out to investigate optimal conditions for stimulation of genital tract CD4(+) T-cell responses, using adoptive transfer of mouse DO11.10 TCR transgenic T cells specific for OVA and OVA conjugated to cholera toxin (CT) as an immunogen. We observed that progesterone was required for a T-cell response following ivag immunization, whereas estradiol prevented a response. Although i.n. immunization stimulated OVA-specific CD4(+) T-cell responses in the draining LNs, it was substantially less effective compared to ivag. More importantly, an ivag booster immunization was absolutely required to attract T cells to the genital tract mucosa itself. While clinical use of CT is precluded because of its toxicity, we developed a combined adjuvant vector based on a non-toxic derivative of CT and immune-stimulating complexes. The CTA1-DD/immune-stimulating complexes (ISCOMs) adjuvant together with major outer membrane protein was effective at stimulating genital tract CD4(+) T-cell immunity and protection against a live chlamydial infection, which holds promise for the development of mucosal vaccines against sexually transmitted infections.

CD4âº T-cell immunity in the female genital tract is critically dependent on local mucosal immunization.

Mice lacking the transcription factor T-bet in the innate immune system develop microbiota-dependent colitis. Here, we show that interleukin-17A (IL-17A)-producing IL-7Rα(+) innate lymphoid cells (ILCs) were potent promoters of disease in Tbx21(-/-)Rag2(-/-) ulcerative colitis (TRUC) mice. TNF-α produced by CD103(-)CD11b(+) dendritic cells synergized with IL-23 to drive IL-17A production by ILCs, demonstrating a previously unrecognized layer of cellular crosstalk between dendritic cells and ILCs. We have identified Helicobacter typhlonius as a key disease trigger driving excess TNF-α production and promoting colitis in TRUC mice. Crucially, T-bet also suppressed the expression of IL-7R, a key molecule involved in controlling intestinal ILC homeostasis. The importance of IL-7R signaling in TRUC disease was highlighted by the dramatic reduction in intestinal ILCs and attenuated colitis following IL-7R blockade. Taken together, these data demonstrate the mechanism by which T-bet regulates the complex interplay between mucosal dendritic cells, ILCs, and the intestinal microbiota.

The transcription factor T-bet regulates intestinal inflammation mediated by interleukin-7 receptor+ innate lymphoid cells.

Chemokine-dependent localization of specific B cell subsets within the immune microarchitecture is essential to ensure successful cognate interactions. Although cognate interactions between T cells and memory B cells (B(mem)) are essential for the secondary humoral immune responses, the chemokine response patterns of B(mem) cells are largely unknown. In contrast to naive B cells, this study shows that Ag-specific B(mem) cells have heightened expression of CCR6 and a selective chemotactic response to the CCR6 ligand, CCL20. Although CCR6 appears be nonessential for the initial clonal expansion and maintenance of B(mem), CCR6 is essential for the ability of B(mem) to respond to a recall response to their cognate Ag. This dependency was deemed intrinsic by studies in CCR6-deficient mice and in bone marrow chimeric mice where CCR6 deficiency was limited to the B cell lineage. Finally, the mis-positioning of CCR6-deficient B(mem) was revealed by immunohistological analysis with an altered distribution of CCR6-deficient B(mem) from the marginal and perifollicular to the follicular/germinal center area.

CCR6-dependent positioning of memory B cells is essential for their ability to mount a recall response to antigen.

Pharmacological induction of hypoxia-inducible factor (HIF), a global transcriptional regulator of the hypoxic response, by prolyl hydroxylase inhibitors (PHDi) is protective in murine models of colitis, and epithelial cells are critical for the observed therapeutic efficacy. Because systemic HIF activation may lead to potentially negative off-target effects, we hypothesized that targeting epithelial HIF through oral delivery of PHDi would be sufficient to protect against colitis in a mouse model.

Oral delivery of prolyl hydroxylase inhibitor: AKB-4924 promotes localized mucosal healing in a mouse model of colitis.

Thymus-derived regulatory T cells (Tregs) mediate dominant peripheral tolerance and treat experimental colitis. Tregs can be expanded from patient blood and were safely used in recent phase 1 studies in graft versus host disease and type 1 diabetes. Treg cell therapy is also conceptually attractive for Crohn's disease (CD). However, barriers exist to this approach. The stability of Tregs expanded from Crohn's blood is unknown. The potential for adoptively transferred Tregs to express interleukin-17 and exacerbate Crohn's lesions is of concern. Mucosal T cells are resistant to Treg-mediated suppression in active CD. The capacity for expanded Tregs to home to gut and lymphoid tissue is unknown.

Developing in vitro expanded CD45RA+ regulatory T cells as an adoptive cell therapy for Crohn's disease.

Colon targeted drug delivery is an active area of research for local diseases affecting the colon, as it improves the efficacy of therapeutics and enables localized treatment, which reduces systemic toxicity. Targeted delivery of therapeutics to the colon is particularly advantageous for the treatment of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease. Advances in oral drug delivery design have significantly improved the bioavailability of drugs to the colon; however in order for a drug to have therapeutic efficacy during disease, considerations must be made for the altered physiology of the gastrointestinal (GI) tract that is associated with GI inflammation. Nanotechnology has been used in oral dosage formulation design as strategies to further enhance uptake into diseased tissue within the colon. This review will describe some of the physiological challenges faced by orally administered delivery systems in IBD, the important developments in orally administered nano-delivery systems for colon targeting, and the future advances of this research.

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue.

Retinoic acid (RA) is a critical regulator of the intestinal adaptive immune response. However, the intrinsic impact of RA on B cell differentiation in the regulation of gut humoral immunity in vivo has never been directly shown. To address this issue, we have been able to generate a mouse model where B cells specifically express a dominant-negative receptor α for RA. In this study, we show that the silencing of RA signaling in B cells reduces the numbers of IgA(+) Ab-secreting cells both in vitro and in vivo, suggesting that RA has a direct effect on IgA plasma cell differentiation. Moreover, the lack of RA signaling in B cells abrogates Ag-specific IgA responses after oral immunization and affects the microbiota composition. In conclusion, these results suggest that RA signaling in B cells through the RA receptor α is important to generate an effective gut humoral response and to maintain a normal microbiota composition.

Cutting Edge: Retinoic Acid Signaling in B Cells Is Essential for Oral Immunization and Microflora Composition.

Inflammatory bowel disease is associated with a number of comorbidities that arise at extraintestinal sites, including the lung. Pulmonary manifestations reported in inflammatory bowel disease include bronchiectasis, chronic bronchitis and importantly, a range of subclinical respiratory abnormalities that are often overlooked in routine clinical evaluation. Whereas evidence for the pulmonary manifestations of Inflammatory bowel disease is increasing, little is known about the immunologic and physiologic mechanisms regulating cross-talk between the gut and lung during disease. This review examines reported lung involvement in Inflammatory bowel disease and discusses the possible immune pathways that underlie pulmonary pathologies. These mechanisms include dysfunctional immune-cell homing, systemic inflammation, and microbial dysbiosis; all of which may contribute to Inflammatory bowel disease-induced pulmonary inflammation. These mechanisms are discussed in the context of our current knowledge of the shared mucosal immune system and the immunology of Inflammatory bowel disease.

Potential mechanisms regulating pulmonary pathology in inflammatory bowel disease.

Gastrointestinal conditions may be broadly classified into two: organic and functional disease, with functional disorders accounting for the majority of patients with chronic gastrointestinal symptoms. Functional gastrointestinal disorders (FGIDs) present with no obvious pathology or well-accepted biochemical mechanism and, as such, treatment strategies are limited and focus on symptoms rather than cure. Irritable bowel syndrome and functional dyspepsia are the most widely recognised FGIDs, and there is a growing body of evidence to suggest an underlying inflammatory phenotype in subsets with these conditions. Here, we discuss the current knowledge of immune involvement in FGIDs and the commonalities between the different manifestations of FGIDs and propose a new hypothesis, potentially defining an underlying immunopathological basis of these conditions.

Article	Year
Prevalence of safer needle devices and factors associated with their adoption: results of a national hospital survey. Public health reports (Washington, D.C. : 1974)\| PubMed ID: 12477915	2002
Differential CD28 and inducible costimulatory molecule signaling requirements for protective CD4+ T-cell-mediated immunity against genital tract Chlamydia trachomatis infection. Infection and immunity\| PubMed ID: 17635872	2007
Collaboration addresses information and education needs of an urban public health workforce. Journal of the Medical Library Association : JMLA\| PubMed ID: 17641775	2007
Correction and use of biomedical literature affected by scientific misconduct. Science and engineering ethics\| PubMed ID: 17703606	2007
The female lower genital tract is a privileged compartment with IL-10 producing dendritic cells and poor Th1 immunity following Chlamydia trachomatis infection. PLoS pathogens\| PubMed ID: 21079691	2010
CD4âº T-cell immunity in the female genital tract is critically dependent on local mucosal immunization. European journal of immunology\| PubMed ID: 21681740	2011
The transcription factor T-bet regulates intestinal inflammation mediated by interleukin-7 receptor+ innate lymphoid cells. Immunity\| PubMed ID: 23063332	2012
CCR6-dependent positioning of memory B cells is essential for their ability to mount a recall response to antigen. Journal of immunology (Baltimore, Md. : 1950)\| PubMed ID: 25505290	2015
Oral delivery of prolyl hydroxylase inhibitor: AKB-4924 promotes localized mucosal healing in a mouse model of colitis. Inflammatory bowel diseases\| PubMed ID: 25545377	2015
Developing in vitro expanded CD45RA+ regulatory T cells as an adoptive cell therapy for Crohn's disease. Gut\| PubMed ID: 25715355	2015
Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue. Nanomedicine : nanotechnology, biology, and medicine\| PubMed ID: 25784453	2015
Cutting Edge: Retinoic Acid Signaling in B Cells Is Essential for Oral Immunization and Microflora Composition. Journal of immunology (Baltimore, Md. : 1950)\| PubMed ID: 26163586	2015
Potential mechanisms regulating pulmonary pathology in inflammatory bowel disease. Journal of leukocyte biology\| PubMed ID: 26307547	2015
Immune dysregulation in the functional gastrointestinal disorders. European journal of clinical investigation\| PubMed ID: 26444549	2015

Ellen Marks

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