Regulation of Immunity to Respiratory Syncytial Virus by Dendritic Cells, Toll-Like Receptors, and Notch

The activation and maintenance of pulmonary viral disease is regulated at multiple levels and determined by the early innate response to the pathogenic stimuli. Subsequent activation events that rely directly and indirectly on the virus itself can alter the development and severity of the ensuing immunopathologic responses. In the present review we outline several interconnected mechanisms that rely on the early recognition of viral nucleic acid for the most appropriate anti-viral immune responses, including TLRs and Notch activation in DCs and T cells. Deviation or persistence of the immune response to respiratory viruses may impact significantly on the severity of the responses. While these mechanisms are likely similar in most respiratory viral infections, this review will focus on findings with respiratory syncytial virus (RSV) infections.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63262/1/vim.2007.0110.pd

The Hypervelocity Star SDSS J090745.0+024507 is a Short-Period Variable

We present high-precision photometry of the hypervelocity star SDSS J090745.0+024507 (HVS), which has a Galactic rest-frame radial velocity of v=709 km/s, and so has likely been ejected from the supermassive black hole in the Galactic center. Our data were obtained on two nights using the MMT 6.5m telescope, and is supplemented by lower precision photometry obtained on four nights using the FLWO 1.2m telescope. The high-precision photometry indicates that the HVS is a short-period, low-amplitude variable, with period P=0.2-2 days and amplitude A = 2-10%. Together with the known effective temperature of T_eff ~ 10,500 K (spectral type B9), this variability implies that the HVS is a member of the class of slowly pulsating B-type main sequence stars, thus resolving the previously-reported two-fold degeneracy in the luminosity and distance of the star. The HVS has a heliocentric distance of 71 kpc, and an age of ~0.35 Gyr. The time of ejection from the center of the Galaxy is < 100 Myr, and thus the existence of the OS constitutes observational evidence of a population of young stars in the proximity of the central supermassive black hole ~0.1 Gyr ago. It is possible that the HVS was a member of a binary that was tidally disrupted by the central black hole; we discuss constraints on the properties of the companion's orbit.Comment: ApJL, submitted, 4 pages, 4 figure

The Effect of a Western Diet on Hepatic Autophagy in Age Accelerated SAMP8 Mice

Non-alcoholic steatohepatitis (NASH) is characterized as a dysregulation of hepatic lipid metabolism and a chronic inflammatory state. It is hypothesized the link between lipid dysregulation and inflammation may be due in part to defective hepatic autophagy and reduced mitochondrial capacity to oxidize fatty acids. It remains to be determined; however, the effects of a Western diet on hepatic autophagy and mitochondrial function during aging. PURPOSE: The purpose of this study was to determine the effect of a high-fat high fructose diet (HFF) on markers of hepatic autophagy and mitochondrial function in an age accelerated mouse model. METHODS: Twenty week old, male and female, SAMP8 mice (n=49) were randomly assigned, matching for gender, to either a standard chow (SC) or HFF (45% fat, 24% fructose) diet for 32 weeks. Liver tissue was analyzed for mRNA expression of autophagic (BNIP3, Beclin 1, p62, and Atg7) and mitochondrial (PGC1α and COXIV) genes. Differences between gender and dietary groups were identified by a 2 x 2 ANOVA and statistical significance was set at p\u3c0.05. RESULTS: Following 32 weeks of feeding, male mice fed the HFF diet were significantly heavier than male mice in the SC group (31.6 g vs 26.5 g; p=0.001); however, no difference was observed between diet groups for female mice. The HFF diet resulted in higher autophagic activity as observed by Beclin 1 (+36%; p=0.001) and BNIP3 (+40%; P=0.003) expression. Despite the higher autophagic activity, p62 was higher (+31%; p\u3c0.001) in the HFF compared to the SC group, suggesting impaired autophagic flux. In addition, mitochondrial COXIV expression was elevated (+43%; P\u3c0.001) in the HFF group compared to the SC group suggesting increased β-oxidation. Overall, the expression of all autophagic and mitochondrial markers was higher in male compared to female mice; however, both sexes responded similarly to the HFF diet. CONCLUSION: Despite the higher expression of autophagic and mitochondrial genes, elevated expression of p62 suggests an impaired autophagic flux in age accelerated mice following a Western diet

Impaired CD4 + T-cell proliferation and effector function correlates with repressive histone methylation events in a mouse model of severe sepsis

Immunosuppression following severe sepsis remains a significant human health concern, as long-term morbidity and mortality rates of patients who have recovered from life-threatening septic shock remain poor. Mouse models of severe sepsis indicate this immunosuppression may be partly due to alterations in myeloid cell function; however, the effect of severe sepsis on subsequent CD4 + T-cell responses remains unclear. In the present study, CD4 + T cells from mice subjected to an experimental model of severe sepsis (cecal ligation and puncture (CLP)) were analyzed in vitro . CD4 + CD62L + T cells from CLP mice exhibited reduced proliferative capacity and altered gene expression. Additionally, CD4 + CD62L + T cells from CLP mice exhibit dysregulated cytokine production after in vitro skewing with exogenous cytokines, indicating a decreased capability of these cells to commit to either the T H 1 or T H 2 lineage. Repressive histone methylation marks were also evident at promoter regions for the T H 1 cytokine IFN-Γ and the T H 2 transcription factor GATA-3 in naÏve CD4 + T cells from CLP mice. These results provide evidence that CD4 + T-cell subsets from post-septic mice exhibit defects in activation and effector function, possibly due to chromatin remodeling proximal to genes involved in cytokine production or gene transcription.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71365/1/998_ftp.pd

Dietary Enrichment of Fish-Oils Attenuates Diet-Induced Obesity and Hepatic Steatosis

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of excess hepatic fat, exceeding 5% of total liver mass. NAFLD is present in one-third of Americans and up to 90% in those who are obese. NAFLD develops largely in part to consumption of a Western diet, defined as 40-60% kcal from saturated fats; however, a diet rich in fish-oils may prevent and reverse the development of steatosis. PURPOSE: To determine the effects of fish oils on the development of NAFLD. METHODS: C57BL/6 (n=91) mice were randomly assigned to four dietary groups for 32-weeks: 10% lard (LFL), 10% fish-oil (LFFO), 41% lard (HFL), or 41% fish-oil (HFFO) diet. Significant differences (p\u3c0.05) between groups were identified by a one-way ANOVA. RESULTS: When compared to HFFO, mice in the HFL group saw an greater (Table 1) body mass and net glucose AUC by 13% (p\u3c0.001) and 24% (p=0.08), respectively. No significant difference was observed between LFL and LFFO for body mass, net glucose AUC or HOMA-IR. This is interesting given no significant difference was observed between groups for the mean weekly caloric intake. HFFO mice showed an 86% lower (p\u3c0.001) total hepatic lipid and 4.8-fold lower (p\u3c0.001) hepatic triglyceride concentration when compared to HFL. HFFO mice also saw a 32% lower (p\u3c0.001) total hepatic cholesterol when compared to HFL. There was no significant difference in total hepatic lipids between LFL and LFFO. CONCLUSION: Despite for no significant difference in caloric intake between high-fat diet groups, consumption of a high-fat diet rich in fish-oils prevented dietary induced obesity, insulin resistance and hepatic steatosis. These results suggest that a diet rich in fish-oils have preventative effects on the development of NAFLD

Fish-oils Increase BAMBI Expression to Protect Against Fibrotic Activity in LPS Stimulated Hepatic Tissue

Non-alcoholic steatohepatitis (NASH), defined as excess hepatic lipid and chronic inflammation, provides an environment prone for the development of hepatic fibrosis. Recent evidence suggests that the antifibrotic protein BAMBI (BMP-Activin membrane bound inhibitor) is downregulated in the presence of inflammation, and may be central to the development of fibrosis. Diets rich in omega-3 (w-3) fatty acids are known to provide anti-inflammatory effects; however, the effects of w-3 fatty acids on hepatic fibrosis are not well-established. PURPOSE: To determine the effects of fish-oils on the hepatic fibrosis signaling cascade, following 32-weeks of high-fat feeding in a LPS-induced model of NASH. METHODS: Male C57BL/6 mice were randomly assigned to one of four diets for 32 weeks (n=9/group): low-fat lard based (LFL, 10% kcal fat), low-fat fish-oil based (LFFO, 10% kcal fat), high-fat lard based (HFL, 41% kcal fat), or high-fat fish-oil based (HFFO, 41% kcal fat). Following in situ LPS stimulation, liver mRNA expression of CD14, TLR4, MyD88, BAMBI, and TGF-β1 was quantified using quantitative RT-PCR. Differences between diets were identified using a one-way ANOVA with statistical significance set at p\u3c0.05. RESULTS: Following LPS stimulation, CD14 was increased 2.5 fold (p=0.020) in HFFO when compared to HFL. Despite the increase in CD14, TLR4 showed no difference between groups. In contrast, MyD88 was 2.8 fold greater (p\u3c0.001) in HFL compared to HFFO. In comparison to untreated tissue, BAMBI was 1.7 fold (p=0.017) higher in the HFFO LPS-stimulated tissue, which best explained the 1-fold (p=0.004) lower expression of TGF-β1 in HFFO when compared to HFL post-LPS stimulation. CONCLUSION: Despite the increase in extracellular LPS signaling receptor CD14, the consumption of fish-oils produced a protective intracellular response as observed by an increase in BAMBI and decrease in TGF-β1. These results suggest that a diet high in w-3 fatty acids may protect against the development of hepatic fibrosi

Diet and Sex Differences Induce Unique Alterations of Markers for Blood Brain Barrier Integrity in Age-Accelerated Mice

The role of diet on brain health has received significant attention, with the Western diet (WD) contributing to cerebrovascular alterations and neurodegenerative disease. The blood-brain barrier (BBB) may play a particularly important role as it forms the interface between the peripheral circulation and the central nervous system. The WD has been shown to negatively impact the BBB. Whether there are sex specific differences with diet on BBB integrity remains unclear. PURPOSE: To determine the effect of diet and sex on the mRNA expression of markers of BBB integrity in an age-accelerated mouse model. METHODS: Male and female Senescence Accelerated Mouse-Prone 8 (SAMP8) mice were randomly assigned to a standard diet (SD) or WD formula for a 32-week period, matched for sex, ending at 12-months of age (n=10-14/group). At 12-months of age, cortical brain tissue was evaluated for the expression of mRNA for targets associated with BBB integrity (Cldn-1, Cldn-3, Cldn-5, Cldn-12, F11r, Lsr, Msfd2a, Ocln, Tjp) using quantitative RT-PCR. A two-way ANOVA was used to identify whether mRNA expression of these targets differed with sex, diet, and their interaction. RESULTS: A significant (pCONCLUSION: Overall, female mice presented with higher expression of mRNA markers for BBB integrity, which may be a protective factor. Furthermore, mice fed the WD had lower mRNA expression of markers of BBB integrity suggesting that a Western diet may accelerate the pathogenesis of the disease state

An evaluation of the Johanson model for roller compaction process development for a high dose API

Roller compaction (RC) is a dry granulation technique applied to improve the flow and compressibility of drug formulations. RC implementation for high drug load formulations can be challenging due to flow issues and a high consumption of active pharmaceutical ingredient (API) for robust process development. This work addresses these challenges using process modelling for design and scale-up of an RC process on the same equipment and transfer to different equipment. A modified application of existing models incorporating a new description of mass transport in the feed screw is evaluated for guaifenesin formulations with a 90% drug loading. The model is calibrated using low-throughput data on a Vector Freund TF Mini RC and used to predict ribbon density and throughput for various process settings at high-throughput. It is found that the modelling framework can reasonably predict high-throughput behaviour on the same RC but the predictive performance decreases for transfer between equipment.</p

TLR3 is an endogenous sensor of tissue necrosis during acute inflammatory events

Ligands from dying cells are a source of Toll-like receptor (TLR) activating agents. Although TLR3 is known to respond to RNA from necrotic cells, the relative importance of this response in vivo during acute inflammatory processes has not been fully explored. We observed the involvement of TLR3 activation during experimental polymicrobial septic peritonitis and ischemic gut injury in the absence of an exogenous viral stimulus. In TLR3-deficient mice, increased chemokine/cytokine levels and neutrophil recruitment characterized the initial inflammatory responses in both injury models. However, the levels of inflammatory chemokines and tumor necrosis factor α quickly returned to baseline in tlr3−/− mice, and these mice were protected from the lethal effects of sustained inflammation. Macrophages from tlr3−/− mice responded normally to other TLR ligands but did not respond to RNA from necrotic neutrophils. Importantly, an immunoneutralizing antibody directed against TLR3 attenuated the generation of inflammatory chemokines evoked by byproducts from necrotic neutrophils cultured with wild-type macrophages. In vivo, anti-TLR3 antibody attenuated the tissue injury associated with gut ischemia and significantly decreased sepsis-induced mortality. Collectively, these data show that TLR3 is a regulator of the amplification of immune response and serves an endogenous sensor of necrosis, independent of viral activation