Crohn's disease (CD) is a chronic, immune-mediated, inflammatory disorder of the intestine that has been linked to numerous susceptibility genes, including the immunity-related GTPase (IRG) M (IRGM). IRGs comprise a family of proteins known to confer resistance to intracellular infections through various mechanisms, including regulation of phagosome processing, cell motility, and autophagy. However, despite its association with CD, the role of IRGM and other IRGs in regulating intestinal inflammation is unclear. We investigated the involvement of Irgm1, an ortholog of IRGM, in the genesis of murine intestinal inflammation. After dextran sodium sulfate exposure, Irgm1-deficient [Irgm1 knockout (KO)] mice showed increased acute inflammation in the colon and ileum, with worsened clinical responses. Marked alterations of Paneth cell location and granule morphology were present in Irgm1 KO mice, even without dextran sodium sulfate exposure, and were associated with impaired mitophagy and autophagy in Irgm1 KO intestinal cells (including Paneth cells). This was manifested by frequent tubular and swollen mitochondria and increased LC3-positive autophagic structures. Interestingly, these LC3-positive structures often contained Paneth cell granules. These results suggest that Irgm1 modulates acute inflammatory responses in the mouse intestine, putatively through the regulation of gut autophagic processes, that may be pivotal for proper Paneth cell functioning.

Objective Although polymorphisms of the NOD2 gene predispose to the development of ileal Crohn's disease, the precise mechanisms of this increased susceptibility remain unclear. Previous work has shown that transcript expression of the Paneth cell (PC) antimicrobial peptides (AMPs) α-defensin 4 and α-defensin-related sequence 10 are selectively decreased in Nod2−/− mice. However, the specific mouse background used in this previous study is unclear. In light of recent evidence suggesting that mouse strain strongly influences PC antimicrobial activity, we sought to characterise PC AMP function in commercially available Nod2−/− mice on a C57BL/6 (B6) background. Specifically, we hypothesised that Nod2−/− B6 mice would display reduced AMP expression and activity. Design Wild-type (WT) and Nod2−/− B6 ileal AMP expression was assessed via real-time PCR, acid urea polyacrylamide gel electrophoresis and mass spectrometry. PCs were enumerated using flow cytometry. Functionally, α-defensin bactericidal activity was evaluated using a gel-overlay antimicrobial assay. Faecal microbial composition was determined using 454-sequencing of the bacterial 16S gene in cohoused WT and Nod2−/− littermates. Results WT and Nod2−/− B6 mice displayed similar PC AMP expression patterns, equivalent α-defensin profiles, and identical antimicrobial activity against commensal and pathogenic bacterial strains. Furthermore, minimal differences in gut microbial composition were detected between the two cohoused, littermate mouse groups. Conclusions Our data reveal that Nod2 does not directly regulate PC antimicrobial activity in B6 mice. Moreover, we demonstrate that previously reported Nod2-dependent influences on gut microbial composition may be overcome by environmental factors, such as cohousing with WT littermates.

Background Increasing evidence supports the central role of Paneth cells in maintaining intestinal host-microbial homeostasis. However, the direct impact of host genotype on Paneth cell function remains unclear. Here, we characterize key differences in Paneth cell function and intestinal microbial composition in two widely utilized, genetically distinct mouse strains (C57BL/6 and 129/SvEv). In doing so, we demonstrate critical influences of host genotype on Paneth cell activity and the enteric microbiota. Methodology and Principal Findings Paneth cell numbers were determined by flow cytometry. Antimicrobial peptide (AMP) expression was evaluated using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), acid urea-polyacrylamide gel electrophoresis, and mass spectrometry. Effects of mouse background on microbial composition were assessed by reciprocal colonization of germ-free mice from both background strains, followed by compositional analysis of resultant gut bacterial communities using terminal restriction fragment length polymorphism analysis and 16 S qPCR. Our results revealed that 129/SvEv mice possessed fewer Paneth cells and a divergent AMP profile relative to C57BL/6 counterparts. Novel 129/SvEv á-defensin peptides were identified, including Defa2/18v, Defa11, Defa16, and Defa18. Host genotype profoundly affected the global profile of the intestinal microbiota, while both source and host factors were found to influence specific bacterial groups. Interestingly, ileal α-defensins from 129/SvEv mice displayed attenuated antimicrobial activity against pro-inflammatory E. coli strains, a bacterial species found to be expanded in these animals. Conclusions and Significance This work establishes the important impact of host genotype on Paneth cell function and the composition of the intestinal microbiota. It further identifies specific AMP and microbial alterations in two commonly used inbred mouse strains that have varying susceptibilities to a variety of disorders, ranging from obesity to intestinal inflammation. This will be critical for future studies utilizing these murine backgrounds to study the effects of Paneth cells and the intestinal microbiota on host health and disease.

It is estimated that Haiti has the highest incidence of cervical cancer in the Western Hemisphere. There are currently no sustainable and affordable cervical cancer screening programs in Haiti. The current status of screening services and knowledge of health care professionals was assessed through a Knowledge, Attitudes, and Practices survey on cervical cancer screening and prevention. It was distributed to Project Medishare for Haiti health care workers (n = 27) in the Central Plateau. The majority (22/27) of participants stated pre-cancerous cells could be detected through screening, however, only four had ever performed a pap smear. All of the participants felt a screening program should be started in their area. Our data establishes that knowledge is fairly lacking among healthcare workers and there is an opportunity to train them in simple, cost effective “screen-and-treat” programs that could have a great impact on the overall health of the population.

Clathrin–AP-3 association is dispensable for AP-3 vesicle budding from endosomes, which suggests that AP-3–clathrin interactions differ from those by which AP-1 and AP-2 adaptors productively engage clathrin in vesicle biogenesis.