Enteric Infection with Citrobacter rodentium Induces Coagulative Liver Necrosis and Hepatic Inflammation Prior to Peak Infection and Colonic Disease

Acute and chronic forms of inflammation are known to affect liver responses and susceptibility to disease and injury. Furthermore, intestinal microbiota has been shown critical in mediating inflammatory host responses in various animal models. Using C. rodentium, a known enteric bacterial pathogen, we examined liver responses to gastrointestinal infection at various stages of disease pathogenesis. For the first time, to our knowledge, we show distinct liver pathology associated with enteric infection with C. rodentium in C57BL/6 mice, characterized by increased inflammation and hepatitis index scores as well as prominent periportal hepatocellular coagulative necrosis indicative of thrombotic ischemic injury in a subset of animals during the early course of C. rodentium pathogenesis. Histologic changes in the liver correlated with serum elevation of liver transaminases, systemic and liver resident cytokines, as well as signal transduction changes prior to peak bacterial colonization and colonic disease. C. rodentium infection in C57BL/6 mice provides a potentially useful model to study acute liver injury and inflammatory stress under conditions of gastrointestinal infection analogous to enteropathogenic E. coli infection in humans.United States. Army Research Office (Institute for Soldier Nanotechnology grant 6915539 (SRT))National Institutes of Health (U.S.) (Grant P01 CA026731)National Institutes of Health (U.S.) (Grant P30 ES02109)National Institutes of Health (U.S.) (Toxicology Training grant ES-070220

Examining mindfulness-based stress reduction: Perceptions from minority older adults residing in a low-income housing facility

<p>Abstract</p> <p>Background</p> <p>Mindfulness-based stress reduction (MBSR) programs are becoming increasingly common, but have not been studied in low income minority older populations. We sought to understand which parts of MBSR were most important to practicing MBSR members of this population, and to understand whether they apply their training to daily challenges.</p> <p>Methods</p> <p>We conducted three focus groups with 13 current members of an MBSR program. Participants were African American women over the age of 60 in a low-income housing residence. We tape recorded each session and subsequently used inductive content analysis to identify primary themes.</p> <p>Results and discussion</p> <p>Analysis of the focus group responses revealed three primary themes stress management, applying mindfulness, and the social support of the group meditation. The stressors they cited using MBSR with included growing older with physical pain, medical tests, financial strain, and having grandchildren with significant mental, physical, financial or legal hardships. We found that participants particularly used their MBSR training for coping with medical procedures, and managing both depression and anger.</p> <p>Conclusion</p> <p>A reflective stationary intervention delivered in-residence could be an ideal mechanism to decrease stress in low-income older adult's lives and improve their health.</p

INT reduction is a valid proxy for eukaryotic plankton respiration despite the inherent toxicity of INT and differences in cell wall structure

The reduction of 2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride (INT) is increasingly being used as an indirect method to measure plankton respiration. Its greater sensitivity and shorter incubation time compared to the standard method of measuring the decrease in dissolved oxygen concentration, allows the determination of total and size-fractionated plankton respiration with higher precision and temporal resolution. However, there are still concerns as to the method’s applicability due to the toxicity of INT and the potential differential effect of plankton cell wall composition on the diffusion of INT into the cell, and therefore on the rate of INT reduction. Working with cultures of 5 marine plankton (Thalassiosira pseudonana CCMP1080/5, Emiliania huxleyi RCC1217, Pleurochrysis carterae PLY-406, Scrippsiella sp. RCC1720 and Oxyrrhis marina CCMP1133/5) which have different cell wall compositions (silica frustule, presence/absence of calcite and cellulose plates), we demonstrate that INT does not have a toxic effect on oxygen consumption at short incubation times. There was no difference in the oxygen consumption of a culture to which INT had been added and that of a replicate culture without INT, for periods of time ranging from 1 to 7 hours. For four of the cultures (T. pseudonana CCMP1080/5, P. carterae PLY-406, E. huxleyi RCC1217, and O. marina CCMP1133/5) the log of the rates of dissolved oxygen consumption were linearly related to the log of the rates of INT reduction, and there was no significant difference between the regression lines for each culture (ANCOVA test, F = 1.696, df = 3, p = 0.18). Thus, INT reduction is not affected by the structure of the plankton cell wall and a single INT reduction to oxygen consumption conversion equation is appropriate for this range of eukaryotic plankton. These results further support the use of the INT technique as a valid proxy for marine plankton respiration

The EHEC Type III Effector NleL Is an E3 Ubiquitin Ligase That Modulates Pedestal Formation

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic colitis and may result in potentially fatal hemolytic uremia syndrome in humans. EHEC colonize the intestinal mucosa and promote the formation of actin-rich pedestals via translocated type III effectors. Two EHEC type III secreted effectors, Tir and EspFu/TccP, are key players for pedestal formation. We discovered that an EHEC effector protein called Non-LEE-encoded Ligase (NleL) is an E3 ubiquitin ligase. In vitro, we showed that the NleL C753 residue is critical for its E3 ligase activity. Functionally, we demonstrated that NleL E3 ubiquitin ligase activity is involved in modulating Tir-mediated pedestal formation. Surprisingly, EHEC mutant strain deficient in the E3 ligase activity induced more pedestals than the wild-type strain. The canonical EPEC strain E2348/69 normally lacks the nleL gene, and the ectopic expression of the wild-type EHEC nleL, but not the catalytically-deficient nleL(C753A) mutant, in this strain resulted in fewer actin-rich pedestals. Furthermore, we showed that the C. rodentium NleL homolog is a E3 ubiquitin ligase and is required for efficient infection of murine colonic epithelial cells in vivo. In summary, our study demonstrated that EHEC utilizes NleL E3 ubiquitin ligase activity to modulate Tir-mediated pedestal formation.National Institutes of Health (U.S.) (grant AI078092)National Institutes of Health (U.S.) (grant AI068655

Serum Proteome and Cytokine Analysis in a Longitudinal Cohort of Adults with Primary Dengue Infection Reveals Predictive Markers of DHF

10.1371/journal.pntd.0001887PLoS Neglected Tropical Diseases611

MITOCHONDRIAL BIOGENESIS AFTER REPEATED BOUTS OF DISUSE

Jacob L. Brown1, Richard A. Perry, Jr1., Kevin L. Shimkus2,David E. Lee1, Megan E. Rosa1, Jessica M. Cardin2, Lemuel A. Brown1, Elizabeth K. McBee1, Yasaman Sharazi-Fard2, Harry Hogan2, James D. Fluckey2, Tyrone A. Washington1 & Nicholas P.Greene1,2 1University of Arkansas, Fayetteville, Arkansas. 2Texas A&M University, College Station, Texas Muscular disuse affects a great number of people have sedentary lifestyles and/or chronic disease. Disuse has been shown to cause severe muscular atrophy and to disrupt mitochondrial quality. PURPOSE: To examine if disuse affects mitochondrial biogenesis, and if resistance exercise following bouts of unloading can promote biogenesis. METHODS: Sprague-Dawley rats were subjected to chronic disuse atrophy by hindlimb unloading (28-d, 1HU) followed by ambulatory recovery (56-d) with (1HU+EX) and without (1HU+REC) resistance exercise. To mimic repeated bouts of disuse animals were subjected to a second bout of HU (28-d, 2HU) and again allowed ambulatory recovery with (2HU+EX) or without (2HU+REC) resistance exercise. Control (CON) animals were allowed normal cage activity throughout. Samples were analyzed for Pgc-1α, Tfam, Nrf2 and Pparα gene expression by real time RT-PCR. To test if disuse impacted mitochondrial biogenesis regulators a T-Test was performed between CON and 1HU groups, to test impact of reloading and exercise data were analyzed by one-way ANOVA across all groups with α set at PRESULTS: Pgc-1α expression decreased by 59% (p=0.042) and Nrf2 by 75% (p=0.047) following disuse (1HU) compared to CON. 1HU+Ex showed a 280% increase in Pparα expression (p=0.005) as well as a 278% increase in Tfam expression (p=0.013) compared to CON. Pgc-1α, Pparα, and Tfam displayed a greater increase in expression with exercise recovery (1HU+Ex) than without (1HU+Rec). Pgc-1α showed an 80% increase in expression (p=0.05), Pparα showed a 208% increase in expression (p=0.01), and Tfam showed a 195% increase in expression (p=0.01) when comparing 1HU+Ex and 1HU+Rec. Nrf2 decreased by 61% (p=0.008) with 2HU. Expression of other biogenesis markers was not changed in the 2HU group. Neither 2HU+Ex nor 2HU+Rec were able to attenuate the loss of Nrf2 expression. CONCLUSION: A single bout of disuse significantly decreases the expression of Pgc-1α and Nrf2. 1HU+Ex promotes mitochondrial biogenesis more than 1HU+Rec. Multiple bouts of disuse decreases the expression of Nrf2. 2HU+Ex and 2HU+Rec does not attenuate the loss of Nrf2 expression. More research needs to be conducted to examine other aspects of mitochondrial quality such as mitochondrial dynamics and autophagy. Funded By National Space Biomedical Research Institut

AUTOPHAGY FOLLOWING MULTIPLE BOUTS OF HINDLIMB UNLOADING

Elizabeth K. McBee1, Jacob L. Brown1, Richard A. Perry, Jr1, Kevin L. Shimkus2,David E. Lee1, Megan E. Rosa1, Jessica M. Cardin2, Lemuel A. Brown1, Yasaman Shirazi-Fard2, Harry A. Hogan2, James D. Fluckey2, Tyrone A. Washington1, Nicholas P. Greene1,2 1University of Arkansas, Fayetteville, AR. 2Texas A&M University, College Station, TX; e-mail: [email protected] Muscular disuse affects an abundance of people with sedentary lifestyles and/or chronic diseases. Disuse has proven to cause severe muscular atrophy and disrupt mitochondrial quality. Autophagy is a cellular mechanism used to remove wasteful or damaged materials, mitophagy is the process of autophagically removing presumably damaged mitochondria. Beclin1 and Atg7 are machinery for autophagy, while Bnip3 specifically regulates mitophagy. Any dysregulation of autophagic processes may significantly impair cellular health following muscle disuse. PURPOSE: The purpose of this study was to investigate whether multiple bouts of muscle disuse (hindlimb unloading, HU) affect the expression of markers for autophagy. METHODS: Sprague-Dawley rats were subjected to chronic disuse atrophy by hindlimb unloading (28-d, 1HU) followed by ambulatory recovery (56-d) (1HU+REC). To mimic repeated bouts of disuse, the animals were subjected to a second bout of HU (28-d, 2HU) and then allowed ambulatory recovery (2HU+REC). Control (CON) animals were allowed normal cage activity throughout. Samples were analyzed for Beclin1, Atg7, and Bnip3 mRNA content by real time RT-PCR. To verify if HU impacted autophagy markers pre-planned T-tests were performed comparing CON and 1HU. To test if multiple bouts of disuse and reloading impacted regulators of autophagy, a one-way ANOVA across all groups was employed with α set at p\u3c0.05. RESULTS: Beclin1, Atg7, and Bnip3 mRNA contents were not different, 270% greater, and ~50% lower following 1HU compared to CON, respectively. Across all conditions, Beclin1 was unchanged. Atg7 was not different from CON in 1HU+REC, 2HU, and 2HU+REC groups. Atg7 was ~30% of 1HU in 1HU+REC and 2HU groups. Bnip3 showed no further differences among conditions. CONCLUSION: A single bout of HU enhanced the capacity for general autophagy, while diminishing the capacity for mitophagy. Recovery from repeated bouts of HU did not alter mRNA levels of autophagic markers relative to CON. These data show that autophagic markers are dysregulated with HU, and that animals adapted to multiple bouts of HU, which dampened the impact of subsequent HU on autophagic markers. Funding provided by NASA Grant Number NNX08AQ35