Social media as an emerging tool for reducing prescription opioid misuse risk factors.

Interventions are urgently needed to reduce prescription opioid misuse risk factors, including anxiety and concomitant use of sedatives. However, only a limited number of randomized controlled opioid intervention trials have been conducted. We sought to determine whether an online behavior change/support community, compared to a control Facebook group, could reduce anxiety and opioid misuse among chronic pain patients. 51 high-risk non-cancer chronic pain patients were randomly assigned to either a Harnessing Online Peer Education (HOPE) peer-led online behavior change intervention or a control group (no peer leaders) on Facebook for 12 weeks. Inclusion criteria were: 18 years or older, a UCLA Health System patient, prescribed an opioid for non-cancer chronic pain between 3 and 12 months ago, and a score of ≥9 on the Current Opioid Misuse Measure (COMM) and/or concomitant use of benzodiazepines. Participation in the online community was voluntary. Patients completed baseline and follow-up assessments on Generalized Anxiety Disorder screener (GAD-7), COMM, and frequency of social media discussions about pain and opioid use. Compared to control group participants, intervention participants showed a baseline-to-follow-up decrease in anxiety, and more frequently used social media to discuss pain, prescription opioid use, coping strategies, places to seek help, and alternative therapies for pain. Both groups showed a baseline to follow-up decrease in COMM score. Preliminary results support the use an online community interventions as a low-cost tool to decrease risk for prescription opioid misuse and its complications.

Feasibility of a social media/online community support group intervention among chronic pain patients on opioid therapy.

Aims: Assess whether the Harnessing Online Peer Education (HOPE) social media-based support group can engage patients on opioids at risk for misuse/overdose to discuss risk reduction strategies. Methods: Fifty-one patients on chronic opioid therapy and risk factors for aberrant medication-taking behaviors were randomized to a HOPE intervention or control (Facebook) group. Results: Compared to control group participants, intervention participants had almost 10 times higher posting engagement (n = 411 posts versus 45; 73% versus 52% of participants). Participants discussed coping, pain, medication and non-medication treatments, and other opioid and addiction-related topics. Discussion: Results suggest that a HOPE online community might serve as an effective behavioral intervention tool among chronic pain patients on opioid therapy.

Enteric Helminths Promote Salmonella Coinfection by Altering the Intestinal Metabolome.

Intestinal helminth infections occur predominantly in regions where exposure to enteric bacterial pathogens is also common. Helminth infections inhibit host immunity against microbial pathogens, which has largely been attributed to the induction of regulatory or type 2 (Th2) immune responses. Here we demonstrate an additional 3-way interaction in which helminth infection alters the metabolic environment of the host intestine to enhance bacterial pathogenicity. We show that an ongoing helminth infection increased colonization by Salmonella independently of T regulatory or Th2 cells. Instead, helminth infection altered the metabolic profile of the intestine, which directly enhanced bacterial expression of Salmonella pathogenicity island 1 (SPI-1) genes and increased intracellular invasion. These data reveal a novel mechanism by which a helminth-modified metabolome promotes susceptibility to bacterial coinfection.

A Highly Effective Component Vaccine against Nontyphoidal Salmonella enterica Infections.

UNLABELLED: Nontyphoidal Salmonella enterica (NTS) infections are a major burden to global public health, as they lead to diseases ranging from gastroenteritis to systemic infections and there is currently no vaccine available. Here, we describe a highly effective component vaccine against S. enterica serovar Typhimurium in both gastroenteritis and systemic murine infection models. We devised an approach to generate supernatants of S. enterica serovar Typhimurium, an organism that is highly abundant in virulence factors. Immunization of mice with this supernatant resulted in dramatic protection against a challenge with serovar Typhimurium, showing increased survival in the systemic model and decreased intestinal pathology in the gastrointestinal model. Protection correlated with specific IgA and IgG levels in the serum and specific secretory IgA levels in the feces of immunized mice. Initial characterization of the protective antigens in the bacterial culture supernatants revealed a subset of antigens that exhibited remarkable stability, a highly desirable characteristic of an effective vaccine to be used under suboptimal environmental conditions in developing countries. We were able to purify a subset of the peptides present in the supernatants and show their potential for immunization of mice against serovar Typhimurium resulting in a decreased level of colonization. This component vaccine shows promise with regard to protecting against NTS, and further work should significantly help to establish vaccines against these prevalent infections. IMPORTANCE: Salmonella enterica infections other than typhoid and paratyphoid fever are a major global health burden, as they cause high morbidity and mortality worldwide. Strategies that prevent Salmonella-related diseases are greatly needed, and there is a significant push for the development of vaccines against nontyphoidal Salmonella enterica serovars. In this work, we describe an S. Typhimurium supernatant-derived vaccine that is effective in reducing bacterial colonization in mouse models of gastroenteritis as well as invasive disease. This is a component vaccine that shows high stability to heat, a feature that is important for use under suboptimal conditions, such as those found in sub-Saharan Africa.

Lyn deficiency leads to increased microbiota-dependent intestinal inflammation and susceptibility to enteric pathogens.

The Lyn tyrosine kinase governs the development and function of various immune cells, and its dysregulation has been linked to malignancy and autoimmunity. Using models of chemically induced colitis and enteric infection, we show that Lyn plays a critical role in regulating the intestinal microbiota and inflammatory responses as well as protection from enteric pathogens. Lyn(-/-) mice were highly susceptible to dextran sulfate sodium (DSS) colitis, characterized by significant wasting, rectal bleeding, colonic pathology, and enhanced barrier permeability. Increased DSS susceptibility in Lyn(-/-) mice required the presence of T but not B cells and correlated with dysbiosis and increased IFN-γ(+) and/or IL-17(+) colonic T cells. This dysbiosis was characterized by an expansion of segmented filamentous bacteria, associated with altered intestinal production of IL-22 and IgA, and was transmissible to wild-type mice, resulting in increased susceptibility to DSS. Lyn deficiency also resulted in an inability to control infection by the enteric pathogens Salmonella enterica serovar Typhimurium and Citrobacter rodentium. Lyn(-/-) mice exhibited profound cecal inflammation, bacterial dissemination, and morbidity following S. Typhimurium challenge and greater colonic inflammation throughout the course of C. rodentium infection. These results identify Lyn as a key regulator of the mucosal immune system, governing pathophysiology in multiple models of intestinal disease.

The absence or overexpression of IL-15 drastically alters breast cancer metastasis via effects on NK cells, CD4 T cells, and macrophages.

IL-15 is a cytokine that can affect many immune cells, including NK cells and CD8 T cells. In several tumor models, IL-15 delays primary tumor formation and can prevent or reduce metastasis. In this study, we have employed a model of breast cancer metastasis to examine the mechanism by which IL-15 affects metastasis. When breast tumor cells were injected i.v. into IL-15(-/-), C57BL/6, IL-15 transgenic (TG) and IL-15/IL-15Rα-treated C57BL/6 mice, there were high levels of metastasis in IL-15(-/-) mice and virtually no metastasis in IL-15 TG or IL-15-treated mice. In fact, IL-15(-/-) mice were 10 times more susceptible to metastasis, whereas IL-15 TG mice were at least 10 times more resistant to metastasis when compared with control C57BL/6 mice. Depletion of NK cells from IL-15 TG mice revealed that these cells were important for protection from metastasis. When NK cells were depleted from control C57BL/6 mice, these mice did not form as many metastatic foci as IL-15(-/-) mice, suggesting that other cell types may be contributing to metastasis in the absence of IL-15. We then examined the role of CD4 T cells and macrophages. In IL-15(-/-) mice, in vivo depletion of CD4 T cells decreased metastasis. The lack of IL-15 in IL-15(-/-) mice, and possibly the Th2-polarized CD4 T cells, was found to promote the formation of M2 macrophages that are thought to contribute to metastasis formation. This study reveals that whereas IL-15 effects on NK cells are important, it also has effects on other immune cells that contribute to metastasis.

15-Deoxy-Δ12,14-prostaglandin J2 inhibits macrophage colonization by Salmonella enterica serovar Typhimurium.

15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) is an anti-inflammatory downstream product of the cyclooxygenase enzymes. It has been implicated to play a protective role in a variety of inflammatory mediated diseases, including rheumatoid arthritis, neural damage, and myocardial infarctions. Here we show that 15d-PGJ2 also plays a role in Salmonella infection. Salmonella enterica Typhimurium is a Gram-negative facultative intracellular pathogen that is able to survive and replicate inside phagocytic immune cells, allowing for bacterial dissemination to systemic sites. Salmonella species cause a wide range of morbidity and mortality due to gastroenteritis and typhoid fever. Previously we have shown that in mouse models of typhoid fever, Salmonella infection causes a major perturbation in the prostaglandin pathway. Specifically, we saw that 15d-PGJ2 production was significantly increased in both liver and feces. In this work we show that 15d-PGJ2 production is also significantly increased in macrophages infected with Salmonella. Furthermore, we show that the addition of 15d-PGJ2 to Salmonella infected RAW264.7, J774, and bone marrow derived macrophages is sufficient to significantly reduce bacterial colonization. We also show evidence that 15d-PGJ2 is reducing bacterial uptake by macrophages. 15d-PGJ2 reduces the inflammatory response of these infected macrophages, as evidenced by a reduction in the production of cytokines and reactive nitrogen species. The inflammatory response of the macrophage is important for full Salmonella virulence, as it can give the bacteria cues for virulence. The reduction in bacterial colonization is independent of the expression of Salmonella virulence genes SPI1 and SPI2, and is independent of the 15d-PGJ2 ligand PPAR-γ. 15d-PGJ2 also causes an increase in ERK1/2 phosphorylation in infected macrophages. In conclusion, we show here that 15d-PGJ2 mediates the outcome of bacterial infection, a previously unidentified role for this prostaglandin.

Neutrophil elastase alters the murine gut microbiota resulting in enhanced Salmonella colonization.

The intestinal microbiota has been found to play a central role in the colonization of Salmonella enterica serovar Typhimurium in the gastrointestinal tract. In this study, we present a novel process through which Salmonella benefit from inflammatory induced changes in the microbiota in order to facilitate disease. We show that Salmonella infection in mice causes recruitment of neutrophils to the gut lumen, resulting in significant changes in the composition of the intestinal microbiota. This occurs through the production of the enzyme elastase by neutrophils. Administration of recombinant neutrophil elastase to infected animals under conditions that do not elicit neutrophil recruitment caused shifts in microbiota composition that favored Salmonella colonization, while inhibition of neutrophil elastase reduced colonization. This study reveals a new relationship between the microbiota and the host during infection.

Early life antibiotic-driven changes in microbiota enhance susceptibility to allergic asthma.

Allergic asthma rates have increased steadily in developed countries, arguing for an environmental aetiology. To assess the influence of gut microbiota on experimental murine allergic asthma, we treated neonatal mice with clinical doses of two widely used antibiotics--streptomycin and vancomycin--and evaluated resulting shifts in resident flora and subsequent susceptibility to allergic asthma. Streptomycin treatment had little effect on the microbiota and on disease, whereas vancomycin reduced microbial diversity, shifted the composition of the bacterial population and enhanced disease severity. Neither antibiotic had a significant effect when administered to adult mice. Consistent with the 'hygiene hypothesis', our data support a neonatal, microbiota-driven, specific increase in susceptibility to experimental murine allergic asthma.

Genital HSV-2 infection induces short-term NK cell memory.

NK cells are known as innate immune cells that lack immunological memory. Recently, it has been shown that NK cells remember encounters with chemical haptens that induce contact hypersensitivity and cytomegalovirus infection. Here, we show the existence of NK cell memory following HSV-2 infection. Stimulation with HSV-2 Ags led to higher IFNγ production in NK cells that were exposed 30 days previously to HSV-2, compared to NK cells from naïve mice. More importantly, this increased production of IFNγ in NK cells was independent of B- and T- lymphocytes and specific for the HSV-2 Ags. We also showed that previously exposed NK cells in a B- and T-lymphocyte free environment mediate protection against HSV-2 infection and they are necessary for the protection of mice against HSV-2 infection. Collectively, NK cells remember prior HSV-2 encounters independent of B- and T- lymphocytes leading to protection against HSV-2 mediated morbidity and mortality upon re-exposure.

The gut microbiota: challenging immunology.

For several decades the intestinal microbiota was mainly studied by those investigating infections and diseases associated with gut health, usually from a microbiology point of view. In the past few years, however, it has become apparent that the intestinal microbiota has widespread implications in the field of immunology, and researchers are being compelled to explain how the microbiota contributes to and/or affects their studies.

The intestinal microbiota plays a role in Salmonella-induced colitis independent of pathogen colonization.

The intestinal microbiota is composed of hundreds of species of bacteria, fungi and protozoa and is critical for numerous biological processes, such as nutrient acquisition, vitamin production, and colonization resistance against bacterial pathogens. We studied the role of the intestinal microbiota on host resistance to Salmonella enterica serovar Typhimurium-induced colitis. Using multiple antibiotic treatments in 129S1/SvImJ mice, we showed that disruption of the intestinal microbiota alters host susceptibility to infection. Although all antibiotic treatments caused similar increases in pathogen colonization, the development of enterocolitis was seen only when streptomycin or vancomycin was used; no significant pathology was observed with the use of metronidazole. Interestingly, metronidazole-treated and infected C57BL/6 mice developed severe pathology. We hypothesized that the intestinal microbiota confers resistance to infectious colitis without affecting the ability of S. Typhimurium to colonize the intestine. Indeed, different antibiotic treatments caused distinct shifts in the intestinal microbiota prior to infection. Through fluorescence in situ hybridization, terminal restriction fragment length polymorphism, and real-time PCR, we showed that there is a strong correlation between the intestinal microbiota composition before infection and susceptibility to Salmonella-induced colitis. Members of the Bacteroidetes phylum were present at significantly higher levels in mice resistant to colitis. Further analysis revealed that Porphyromonadaceae levels were also increased in these mice. Conversely, there was a positive correlation between the abundance of Lactobacillus sp. and predisposition to colitis. Our data suggests that different members of the microbiota might be associated with S. Typhimurium colonization and colitis. Dissecting the mechanisms involved in resistance to infection and inflammation will be critical for the development of therapeutic and preventative measures against enteric pathogens.

NK cells require type I IFN receptor for antiviral responses during genital HSV-2 infection.

Type I interferon (IFN) signalling, NK cells and NK cell-derived IFN-γ are critical in the early control of genital HSV-2 infection. We have recently reported that NK cells are the source of early IFN-γ in the genital tract in response to HSV-2. However, the response of NK cells to genital HSV-2 infection is not well defined in the context of type I IFN signalling. Here we show that HSV-2 replication was significantly higher in mice deficient in the type I IFN receptor or NK cells compared to wild type controls. There was no detectable IFN-γ production in the genital washes from IFN-α/ßR(-/-) mice or NK cell depleted mice in response to HSV-2 infection compared to control mice. Absence of the type I IFN receptor does not alter homing of NK cells to the genital mucosa. Moreover, the absence of IL-12 had no significant effect on NK cell-derived IFN-γ. Surprisingly, IFN-α/ßR(-/-) mice had more IL-15 positive cells in the genital mucosa in response to HSV-2 infection compared to control mice. We then examined the expression of IL-15 receptors on NK cells. There was no significant differences in the levels of IL-15 receptor expression on NK cells from IFN-α/ßR(-/-) or control mice. Our data clearly suggest that type I IFN receptor signalling is essential for NK cell activation in response to genital HSV-2 infection, and propose that NK cell activation by IL-15 may involve type I IFNs.

Roadblocks in the gut: barriers to enteric infection.

This review discusses the barriers an enteric pathogen encounters when establishing an infection in the intestinal tract. There are potential barriers in the lumen that increase competition for nutrients and space. The role of mucus layer, and the antimicrobial peptides and secretory IgA sequestered within it, are also significant barriers. After overcoming these defences, the pathogen encounters the epithelial layer. This layer can be broken down into various protective components including enterocytes, Paneth cells, goblet cells, M cells and pathogen recognition receptors. Collectively, these intestinal defences constitute significant barriers that pathogens must overcome to successfully colonize this important mucosal surface.

CD34 mediates intestinal inflammation in Salmonella-infected mice.

CD34 is a highly glycosylated sialomucin expressed on a variety of cells, ranging from vascular endothelial cells to haematopoietic stem cells. Depending on its glycosylation state, CD34 has been shown to promote or inhibit cell adhesion and migration; however, a functional role for CD34 in the gut has not been determined. Using a model of Salmonella-induced gastroenteritis, we investigated the role of CD34 in the context of infection. Upon oral infection, the number of CD34+ cells detected in the submucosa, vascular endothelium and lamina propria significantly increased in S. Typhimurium-infected C57Bl/6 mice. The pathology of S. Typhimurium-infected C57Bl/6 mice was characterized by recruitment of neutrophils to the site of inflammation, submucosal oedema and crypt destruction. In contrast, Cd34(-/-) mice showed a delayed pathology, a defect in inflammatory cell migration into the intestinal tissue and enhanced survival. Importantly, this was not due to a lack of chemotactic signals in Cd34(-/-) mice as these mice had either similar or significantly higher levels of pro-inflammatory cytokines and chemokines post infection when compared with infected C57/Bl6 control mice. In summary, we demonstrate a novel role for CD34 in enhancing migration of inflammatory cells and thereby exacerbating host-mediated immunopathology in the intestine of S. Typhimurium-infected mice.

The role of the immune system in regulating the microbiota.

A diverse population of bacteria, archaea and fungi, collectively known as the microbiota, abounds within the gastrointestinal tract of the mammalian host. This microbial population makes many important contributions to host physiology through inter-kingdom signalling and by providing nutrients that have both local and systemic effects. In a healthy state the overall host-microbial interaction is symbiotic; however, a growing number of diseases have been associated with a dysregulated microbiota. To avoid these consequences, the host exerts substantial effort to maintain proper regulation of the microbiota with respect to localization and composition. Although important to maintaining microbial balance, the host immune response can also be the cause of a disrupted microbiota, contributing to disease severity. Here, we discuss the role of the host in both maintaining and disrupting a balanced gastrointestinal microbiota.

Salmonella SPI-1-mediated neutrophil recruitment during enteric colitis is associated with reduction and alteration in intestinal microbiota.

Gastrointestinal infections involve an interactive tripartite relationship between the invading pathogen, the host, and the host's resident intestinal microbiota. To characterize the host inflammatory response and microbiota alterations during enteric salmonellosis, C57BL/6 mice were pre-treated with a low dose of streptomycin (LD model) and then infected with S. typhimurium strains, including mutants in the two Type III secretion systems, SPI-1 and SPI-2 (invAmut and ssaRmut, respectively). Cecal colonization and inflammation in the LD model were evaluated to assess infection success and progression, and compared to the traditional high dose (HD) model. Perturbations to the microbial community in the LD model were assessed via evaluation of total microbial numbers, the proportion of intestinal γ-Proteobacteria and tRFLP analysis. In the LD model, consistently high colonization by the parental strain (WT) and invAmut S. typhimurium was associated with significant intestinal pathology. However, microbial community profiles were more similar both in numbers and composition between mice infected with the mutant strains, than with the WT strain. Consequently, significant infection-induced inflammation did not always produce similar microbiota perturbations. Large numbers of luminal neutrophils were observed in the ceca of WT-infected, but not in invAmut or ssaRmut infected mice. Neutrophils were thus implicated as a potential mediator of microbiota perturbations during WT enteric salmonellosis. These studies offer a new model of S. typhimurium-induced intestinal disease that retains the three participants of the disease process and further defines the role of virulence factors, the host microbiota, and inflammation in S. typhimurium-induced intestinal disease.

Interleukin-15 expression affects homeostasis and function of B cells through NK cell-derived interferon-gamma.

Interleukin-15 (IL-15) is a cytokine important for the development, maturation, and function of many cells of the immune system including NK, NKT, gammadeltaT, and CD8(+) T cells. The relationship between IL-15 and B lymphocytes however, is not well characterized and is the focus of our study. Previous in vitro reports have shown that IL-15 increases proliferation of B lymphocytes and increases antibody secretion however, this relationship remains inadequately defined in vivo. The focus of this study was to examine the role of IL-15 in B cell homeostasis and function in vivo using mice that either over express IL-15 (IL-15tg mice) or are deficient in IL-15 (IL-15(-/-) mice) production. Here we report significant differences between the B cell populations of IL-15(-/-), C57BL/6, and IL-15tg mice. In fact, increased expression of IL-15 resulted in a significant decrease in the percentage and absolute number of CD19(+) cells. In vitro B cell co-cultures implicate interferon-gamma (IFN-gamma) as the factor responsible for inhibiting B cell proliferation. We also show that IL-15 expression affects B cell function, as B cells from IL-15 transgenic mice produce greater amounts of IgG and IgA than IL-15 knockout mice in vitro. Interestingly, despite significant differences in B cell numbers in these strains, there were no significant differences in total antibody titers in serum and vaginal washes of these mice. Results from our in vivo and in vitro experiments suggest that altered expression of IL-15 affects B cell homeostasis through the induction of NK cell-derived IFN-gamma.

Overexpression of interleukin-15 compromises CD4-dependent adaptive immune responses against herpes simplex virus 2.

Interleukin-15 (IL-15) is necessary for the development and function of NK/NKT cells and the maintenance of naive and memory CD8(+) T cells. In the absence of IL-15, protective innate immunity is not available; however, a functional adaptive immune response against vaginal herpes simplex virus 2 (HSV-2) is generated. Mice overexpressing IL-15 (IL-15tg mice) have higher numbers of NK cells, greater NK-derived gamma interferon, and more CD8(+) T cells. Here we examined the consequences of IL-15 overexpression for innate and adaptive immunity against genital HSV-2. Surprisingly, IL-15tg mice immunized against HSV-2 were not protected against genital HSV-2 challenge compared to control immunized mice. IL-15tg mice had a higher frequency of NK cells in the genital mucosa than control mice. However, immunized IL-15tg mice had significantly lower numbers of HSV-2-specific CD4(+) T cells than B6 mice. We then confirmed that CD4(+) T cells, but not CD8(+) T cells, are essential for protection against intravaginal HSV-2 challenge. Since we observed less protection in immunized IL-15tg mice, we then examined if the adaptive immune responses generated in an environment with overexpression of IL-15 could provide protection against HSV-2 in an environment with normal levels of IL-15 expression. We adoptively transferred immunized cells from IL-15tg and B6 mice into naive RAG-1(-/-) mice and found that the cells from immunized IL-15tg mice were able to provide protection in this IL-15-normal environment. Our data suggest that overexpression of IL-15 results in a reduced CD4(+) T cell-mediated adaptive immune response against genital HSV-2.