Adult Cardiac Progenitor Cell Aggregates Exhibit Survival Benefit Both In Vitro and In Vivo

Background

A major hurdle in the use of exogenous stems cells for therapeutic regeneration of injured myocardium remains the poor survival of implanted cells. To date, the delivery of stem cells into myocardium has largely focused on implantation of cell suspensions.

Methodology and Principal Findings

We hypothesize that delivering progenitor cells in an aggregate form would serve to mimic the endogenous state with proper cell-cell contact, and may aid the survival of implanted cells. Microwell methodologies allow for the culture of homogenous 3D cell aggregates, thereby allowing cell-cell contact. In this study, we find that the culture of cardiac progenitor cells in a 3D cell aggregate augments cell survival and protects against cellular toxins and stressors, including hydrogen peroxide and anoxia/reoxygenation induced cell death. Moreover, using a murine model of cardiac ischemia-reperfusion injury, we find that delivery of cardiac progenitor cells in the form of 3D aggregates improved in vivo survival of implanted cells.

Conclusion

Collectively, our data support the notion that growth in 3D cellular systems and maintenance of cell-cell contact improves exogenous cell survival following delivery into myocardium. These approaches may serve as a strategy to improve cardiovascular cell-based therapies.     

The Role of Nucleus Accumbens Core/Shell in Sleep-Wake Regulation and their Involvement in Modafinil-Induced Arousal

Background

We have previously shown that modafinil promotes wakefulness via dopamine receptor D₁ and D₂ receptors; however, the locus where dopamine acts has not been identified. We proposed that the nucleus accumbens (NAc) that receives the ventral tegmental area dopamine inputs play an important role not only in reward and addiction but also in sleep-wake cycle and in mediating modafinil-induced arousal.

Methodology/Principal Findings

In the present study, we further explored the role of NAc in sleep-wake cycle and sleep homeostasis by ablating the NAc core and shell, respectively, and examined arousal response following modafinil administration. We found that discrete NAc core and shell lesions produced 26.5% and 17.4% increase in total wakefulness per day, respectively, with sleep fragmentation and a reduced sleep rebound after a 6-hr sleep deprivation compared to control. Finally, NAc core but not shell lesions eliminated arousal effects of modafinil.

Conclusions/Significance

These results indicate that the NAc regulates sleep-wake behavior and mediates arousal effects of the midbrain dopamine system and stimulant modafinil.     

Development of Skewed Functionality of HIV-1-Specific Cytotoxic CD8+ T Cells from Primary to Early Chronic Phase of HIV Infection

In recent years, the prevalence of HIV-1 infection has been rapidly increasing among men who have sex with men (MSM). However, it remains unknown how the host immune system responds to the infection in this population. We assessed the quantity of HIV-specific CD8⁺ T-cell responses by using Elispot assay and their functionalities by measuring 5 CD8⁺ T-cell evaluations (IL-2, MIP-1β, CD107a, TNF-α, IFN-γ) with flow cytometry assays among 18 primarily and 37 early chronically HIV-infected MSM. Our results demonstrated that subjects at early chronic phase developed HIV-specific CD8⁺ T-cell responses with higher magnitudes and more diversified functionalities in comparison with those at primary infection. However, populations with IL-2⁺ CD107a⁺ or in combination with other functionality failed to develop in parallel. The multifunctional but not monofunctional HIV-specific CD8⁺ T cells were associated with higher CD4⁺ T -cell counts and lower viral loads. These data revealed that prolonged infection from primary to early chronic infection could selectively increase the functionalities of HIV-specific CD8⁺ T cells in HIV-infected MSM population, the failure to develop IL-2 and cytotoxic functionalities in parallel may explain why the increased HIV-specific CD8⁺ T cells were unable to enhance the containment of HIV-1 replication at the early chronic stage.     

Immune Modulation Mediated by Cryptococcal Laccase Promotes Pulmonary Growth and Brain Dissemination of Virulent Cryptococcus neoformans in Mice

C. neoformans is a leading cause of fatal mycosis linked to CNS dissemination. Laccase, encoded by the LAC1 gene, is an important virulence factor implicated in brain dissemination yet little is known about the mechanism(s) accounting for this observation. Here, we investigated whether the presence or absence of laccase altered the local immune response in the lungs by comparing infections with the highly virulent strain, H99 (which expresses laccase) and mutant strain of H99 deficient in laccase (lac1Δ) in a mouse model of pulmonary infection. We found that LAC1 gene deletion decreased the pulmonary fungal burden and abolished CNS dissemination at weeks 2 and 3. Furthermore, LAC1 deletion lead to: 1) diminished pulmonary eosinophilia; 2) increased accumulation of CD4+ and CD8+ T cells; 3) increased Th1 and Th17 cytokines yet decreased Th2 cytokines; and 4) lung macrophage shifting of the lung macrophage phenotype from M2- towards M1-type activation. Next, we used adoptively transferred CD4+ T cells isolated from pulmonary lymph nodes of mice infected with either lac1Δ or H99 to evaluate the role of laccase-induced immunomodulation on CNS dissemination. We found that in comparison to PBS treated mice, adoptively transferred CD4+ T cells isolated from lac1Δ-infected mice decreased CNS dissemination, while those isolated from H99-infected mice increased CNS dissemination. Collectively, our findings reveal that immune modulation away from Th1/Th17 responses and towards Th2 responses represents a novel mechanism through which laccase can contribute to cryptococcal virulence. Furthermore, our data support the hypothesis that laccase-induced changes in polarization of CD4+ T cells contribute to CNS dissemination.     

Multiple Origins of kdr-type Resistance in the House Fly,Musca domestica

Insecticide resistance is a model phenotype that can be used to investigate evolutionary processes underlying the spread of alleles across a global landscape, while offering valuable insights into solving the problems that resistant pests present to human health and agriculture. Pyrethroids are one of the most widely used classes of insecticides world-wide and they exert their toxic effects through interactions with the voltage-sensitive sodium channel (Vssc). Specific mutations in Vssc (kdr, kdr-his and super-kdr) are known to cause resistance to pyrethroid insecticides in house flies. In order to determine the number of evolutionary origins of kdr, kdr-his and super-kdr, we sequenced a region of Vssc from house flies collected in the USA, Turkey and China. Our phylogenetic analysis of Vssc unequivocally supports the hypothesis of multiple independent origins of kdr, super-kdr and kdr-his on an unprecedented geographic scale. The implications of these evolutionary processes on pest management are discussed.     

Met receptor tyrosine kinase signaling induces secretion of the angiogenic chemokine interleukin-8/CXCL8 in pancreatic cancer

At diagnosis, the majority of pancreatic cancer patients present with advanced disease when curative resection is no longer feasible and current therapeutic treatments are largely ineffective. An improved understanding of molecular targets for effective intervention of pancreatic cancer is thus urgent. The Met receptor tyrosine kinase is one candidate implicated in pancreatic cancer. Notably, Met is over expressed in up to 80% of invasive pancreatic cancers but not in normal ductal cells correlating with poor overall patient survival and increased recurrence rates following surgical resection. However the functional role of Met signaling in pancreatic cancer remains poorly understood. Here we used RNA interference to directly examine the pathobiological importance of increased Met signaling for pancreatic cancer. We show that Met knockdown in pancreatic tumor cells results in decreased cell survival, cell invasion, and migration on collagen I in vitro. Using an orthotopic model for pancreatic cancer, we provide in vivo evidence that Met knockdown reduced tumor burden correlating with decreased cell survival and tumor angiogenesis, with minimal effect on cell growth. Notably, we report that Met signaling regulates the secretion of the pro-angiogenic chemokine interleukin-8/CXCL8. Our data showing that the interleukin-8 receptors CXCR1 and CXCR2 are not expressed on pancreatic tumor cells, suggests a paracrine mechanism by which Met signaling regulates interleukin-8 secretion to remodel the tumor microenvironment, a novel finding that could have important clinical implications for improving the effectiveness of treatments for pancreatic cancer.     

Negative Affect Mediates Effects of Psychological Stress on Disordered Eating in Young Chinese Women

Background

The bi-relationships between psychological stress, negative affect and disordered eating has been well studied in western culture, while tri-relationship among them, i.e. how some of those factors influence these bi-relationships, has rarely been studied. However, there has been little related study in the different Chinese culture. This study was conducted to investigate the bi-relationships and tri-relationship between psychological stress, negative affect, and disordered eating attitudes and behaviors in young Chinese women.

Methodology

A total of 245 young Chinese policewomen employed to carry out health and safety checks at the 2010 Shanghai World Expo were recruited in this study. The Chinese version of the Perceived Stress Scale (PSS-10), Beck Depression Inventory Revised (BDI-II), Beck Anxiety Inventory (BAI), and Eating Attitude Test (EAT-26) were administered to all participants.

Principal Findings

The total scores of PSS-10, BDI-II and BAI were all highly correlated with that of EAT-26. The PSS-10 score significantly correlated with both BDI-II and BAI scores. There was no statistically significant direct effect from perceived stress to disordered eating (–0.012, 95%CI: –.038∼0.006, p = 0.357), however, the indirect effects from PSS-10 via affect factors were statistically significant, e.g. the estimated mediation effects from PSS to EAT-26 via depression and anxiety were 0.036 (95%CI: 0.022∼0.044, p<0.001) and 0.015 (95%CI: 0.005∼0.023, p<0.01), respectively.

Conclusions

Perceived stress and negative affects of depression and anxiety were demonstrated to be strongly associated with disordered eating. Negative affect mediated the relationship between perceived stress and disordered eating. The findings suggest that effective interventions and preventative programmes for disordered eating should pay more attention to depression and anxiety among the young Chinese female population.     

Efficient production of pyruvate from DL-lactate by the lactate-utilizing strain Pseudomonas stutzeri SDM

Background

The platform chemical lactate is currently produced mainly through the fermentation of sugars presented in biomass. Besides the synthesis of biodegradable polylactate, lactate is also viewed as a feedstock for the green chemistry of the future. Pyruvate, another important platform chemical, can be produced from lactate through biocatalysis.

Methodology/Principal Findings

It was established that whole cells of Pseudomonas stutzeri SDM catalyze lactate oxidation with lactate-induced NAD-independent lactate dehydrogenases (iLDHs) through the inherent electron transfer chain. Unlike the lactate oxidation processes observed in previous reports, the mechanism underlying lactate oxidation described in the present study excluded the costliness of the cofactor regeneration step and production of the byproduct hydrogen peroxide.

Conclusions/Significance

Biocatalysis conditions were optimized by using the cheap dl-lactate as the substrate and whole cells of the lactate-utilizing P. stutzeri SDM as catalyst. Under optimal conditions, the biocatalytic process produced pyruvate at a high concentration (48.4 g l⁻¹) and a high yield (98%). The bioconversion system provides a promising alternative for the green production of pyruvate.     

GSK3 inhibitor-BIO regulates proliferation of immortalized pancreatic mesenchymal stem cells (iPMSCs)

Background

The small molecule 6-bromoindirubin-30-oxime (BIO), a glycogen synthase kinase 3 (GSK3) inhibitor, is a pharmacological agent known to maintain self-renewal in human and mouse embryonic stem cells (ESCs). However, the precise role of GSK3 in immortalized pancreatic mesenchymal stem cells (iPMSCs) growth and survival is not completely understood at present.

Results

To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effect of BIO on iPMSCs. We found that the inactivation of GSK3 by BIO can robustly stimulate iPMSCs proliferation and mass formation as shown by QRT-PCR, western blotting, 5-Bromo-2-deoxyuridine (BrdU) immunostaining assay and tunel assay. However, we did not find the related roles of BIO on β cell differentiation by immunostaining, QRT-PCR assay, glucose-stimulated insulin release and C-peptide content analysis.

Conclusions

These results suggest that BIO plays a key role in the regulation of cell mass proliferation and maintenance of the undifferentiated state of iPMSCs.     

Are Risk Factors Associated with Outcomes in Pancreatic Cancer?

Background

The development of pancreatic cancer is a process in which genes interact with environmental factors. We performed this study to determine the effects of the ABO blood group, obesity, diabetes mellitus, metabolic syndrome (MetS), smoking, alcohol consumption and hepatitis B viral (HBV) infection on patient survival.

Methods

A total of 488 patients with pancreatic cancer were evaluated.

Result

Patients who presented as chronic carriers of HBV infection were younger at disease onset (p = 0.001) and more predominantly male (p = 0.020) than those never exposed to HBV. Patients with MetS had later disease staging (p = 0.000) and a lower degree of pathological differentiation (p = 0.008) than those without MetS. In a univariate analysis, the ABO blood group, smoking and alcohol consumption were not associated with overall survival. HBsAg–positivity and elevated fasting plasma glucose were significantly associated with unfavorable survival though not in the multivariate analysis. The presence of MetS (HR: 1.541, 95% CI: 1.095–2.169, p = 0.013), age ≥65, an elevated CA19–9 baseline level, TNM staging, the type of surgery, the degree of differentiation and chemotherapy were independently associated with overall survival.

Conclusion

We report, for the first time, that patients with chronic HBV infection may represent a special subtype of pancreatic cancer, who have a younger age of disease onset and male dominancy. Patients with MetS had later disease staging and a poorer histological grade. Patients with MetS demonstrated significantly poorer survival.