Gain without pain: adaptation and increased virulence of Zika virus in vertebrate host without fitness cost in mosquito vector

IMPORTANCE

Previously, we modeled direct transmission chains of Zika virus (ZIKV) by serially passaging ZIKV in mice and mosquitoes and found that direct mouse transmission chains selected for viruses with increased virulence in mice and the acquisition of non-synonymous amino acid substitutions. Here, we show that these same mouse-passaged viruses also maintain fitness and transmission capacity in mosquitoes. We used infectious clone-derived viruses to demonstrate that the substitution in nonstructural protein 4A contributes to increased virulence in mice.

In utero intraventricular injection and electroporation of E15 mouse embryos

In-utero in-vivo injection and electroporation of the embryonic mouse neocortex provides a powerful tool for the manipulation of individual progenitors lining the walls of the lateral ventricle. This technique is now widely used to study the processes involved in corticogenesis by over-expressing or knocking down genes and observing the effects on cellular proliferation, migration, and differentiation. In comparison to traditional knockout strategies, in-utero electroporation provides a rapid means to manipulate a population of cells during a specific temporal window. In this video protocol we outline the experimental methodology for preparing mice for surgery, exposing the uterine horns through laporatomy, injecting DNA into the lateral ventricles of the developing embryo, electroporating DNA into the progenitors lining the lateral wall, and caring for animals post-surgery. Our laboratory uses this protocol for surgeries on E13-E16 mice, however it is most commonly performed at E15 as shown in this video.

The Challenge of Changing Roles and Improving Surgical Care Now: Crew Resource Management Approach

Many surgeons are also pilots; the two activities demand similar skill sets. Surgeons have developed an interest in aviation models for managing risk and reducing adverse events, such as Crew Resource Management training. This article provides seven suggestions from aviators that might be adopted by surgeons in an effort to improve surgical care and mitigate patient harm. Each suggestion is offered based on the value added to aviation, with an acknowledgment that the suggestion may be more or less applicable in surgery. The suggestions for dealing with the changing roles for surgeons are: Crew Resource Management-type training to improve teamwork should be required for hospital credentialing, surgeons should brief the operating room team before an operation, surgeons should write standards specific to their organization, surgeons should recognize fatigue and age as factors in performance, surgeons should have “check-rides” as a part of the credentialing process, surgeons should abandon the mortality and morbidity conference in favor of a data collection system that effectively examines adverse events for root causes of error, and all members of the surgical team should be subject to mandatory, random drug testing.

Immunostimulatory DNA sequences inhibit respiratory syncytial viral load, airway inflammation, and mucus secretion

BACKGROUND

Immunostimulatory DNA sequences (ISS) activate the innate immune system to generate antiviral cytokines, such as IFN-gamma.

OBJECTIVE

This study investigated whether ISS could reduce viral load, mucus secretion, airway inflammation, and airway hyperreactivity to methacholine in a mouse model of respiratory syncytial virus (RSV) infection.

METHODS

Mice were pretreated with ISS 6 days before RSV infection, and lung indices of RSV viral load (viral titer and PCR), bronchoalveolar lavage fluid cytokines (IFN-gamma), airway inflammation (peribronchial inflammation and periodic acid-Schiff-positive mucus cells), and airway hyperreactivity (methacholine responsiveness) were assessed 4 to 6 days after RSV infection.

RESULTS

ISS induced the expression of the antiviral cytokine IFN-gamma in the lung, and this was associated with significantly reduced RSV viral titers, mucus secretion, and peribronchial inflammation. ISS reduced, but did not significantly inhibit, RSV-induced airway hyperreactivity to methacholine.

CONCLUSION

Because ISS induced significant levels of lung IFN-gamma, an immunization strategy based solely on the administration of IFN-gamma may be insufficient to inhibit RSV-induced airway hyperreactivity to methacholine, an endpoint important in the subset of RSV-infected subjects with asthma.

Immunostimulatory DNA mediates inhibition of eosinophilic inflammation and airway hyperreactivity independent of natural killer cells in vivo

BACKGROUND

Immunostimulatory DNA sequences (ISS) inhibit eosinophilic inflammation and airway hyperreactivity in mouse models of asthma. In vitro ISS activate natural killer (NK) cells to secrete IFN-gamma, and this cytokine is hypothesized to contribute to the antiallergic effect of ISS in vivo.

OBJECTIVE

We investigated whether ISS activation of NK cells is important in mediating the reduction in airway hyperreactivity and the antieosinophilic effect of ISS in vivo.

METHODS

We assessed whether ISS modulated the development of eosinophilic airway inflammation and airway hyperreactivity to methacholine in ovalbumin (OVA)-sensitized and OVA allergen-challenged mice pretreated with an antibody to deplete NK cells.

RESULTS

Mice sensitized and challenged with OVA had significant bronchoalveolar lavage and lung eosinophilia, as well as airway hyperresponsiveness. ISS induced significant inhibition of bronchoalveolar lavage and lung eosinophilia, as well as airway hyperresponsiveness, in OVA-sensitized mice pretreated before OVA challenge with an NK cell-depleting antibody (NK(-) mice), as well as in mice pretreated with a control non-NK cell-depleting antibody (NK(+) mice). The NK cell-depleting antibody inhibited ISS-induced IFN-gamma production by spleen cells.

CONCLUSION

These studies demonstrate that depletion of NK cells has no significant effect on ISS-mediated inhibition of airway eosinophilia and airway hyperresponsiveness in vivo, suggesting that non-NK cells and cytokines other than IFN-gamma derived from NK cells mediate the majority of the ISS-inhibitory effect on eosinophilic inflammation and airway hyperresponsiveness in vivo.

Eosinophil tissue recruitment to sites of allergic inflammation in the lung is platelet endothelial cell adhesion molecule independent

Platelet endothelial cell adhesion molecule (PECAM or CD31) is a cell adhesion molecule expressed on circulating leukocytes and endothelial cells that plays an important role in mediating neutrophil and monocyte transendothelial migration in vivo. In this study, we investigated whether eosinophils, like neutrophils and monocytes, utilize PECAM for tissue recruitment to sites of allergic inflammation in vivo. Eosinophils express similar levels of PECAM as neutrophils as assessed by FACS analysis. RT-PCR studies demonstrate that eosinophils like neutrophils express the six extracellular domains of PECAM. Eosinophils exhibit homophilic binding to recombinant PECAM as assessed in a single-cell micropipette adhesion assay able to measure the biophysical strength of adhesion of eosinophils to recombinant PECAM. The strength of eosinophil adhesion to recombinant PECAM is the same as that of neutrophil binding to recombinant PECAM and can be inhibited with an anti-PECAM Ab. Although eosinophils express functional PECAM, anti-PECAM Abs did not inhibit bronchoalveolar lavage eosinophilia, lung eosinophilia, and airway hyperreactivity to methacholine in a mouse model of OVA-induced asthma in vivo. Thus, in contrast to studies that have demonstrated that neutrophil and monocyte tissue recruitment is PECAM dependent, these studies demonstrate that eosinophil tissue recruitment in vivo in this model is PECAM independent.

Systemic administration of immunostimulatory DNA sequences mediates reversible inhibition of Th2 responses in a mouse model of asthma

This study investigated whether immunostimulatory DNA sequences (ISS) induce a transient or sustained inhibition of Th2 responses to inhaled antigen. We sensitized mice with subcutaneous injections to develop a Th2 response to ovalbumin (ova) and then administered a dose of ISS prior to ova inhalation challenge. Mice were then rechallenged with ova by inhalation a second time at varying time points after the first ova inhalation (1 to 8 weeks later) to determine whether the ISS dose administered prior to the first ova inhalation protected against a subsequent second ova inhalation challenge. A single dose of ISS inhibited the Th2 response to the first inhalation of ova antigen, as well as 4 weeks later to the second inhalation of ova. However, ISS did not inhibit a Th2 response to the second inhalation of ova 8 weeks later. The reversible inhibition of Th2 responses at 8 weeks suggests the need for repeated ISS administration at monthly intervals.

Inhibition of eosinophilic inflammation in allergen-challenged TNF receptor p55/p75--and TNF receptor p55-deficient mice

To determine the relative in vivo importance of tumor necrosis factor (TNF) release after allergen challenge to the subsequent endothelial adhesion and recruitment of eosinophils, we have compared eosinophil recruitment in TNF receptor p55/p75--deficient, TNF receptor p55--deficient, and control wild-type mice challenged with allergen. Bronchoalveolar lavage eosinophil recruitment in TNF receptor p55/p75--deficient and TNF receptor p55--deficient mice challenged with ovalbumin was significantly reduced compared with wild-type mice. To determine the mechanism of inhibition of eosinophil recruitment in TNF receptor-deficient mice, we used intravital microscopy to visualize the rolling and firm adhesion of fluorescently labeled mouse eosinophils in the microvasculature of the allergen-challenged mouse mesentery. Eosinophil rolling as well as eosinophil firm adhesion to endothelium were significantly inhibited in allergen-challenged TNF receptor p55/p75--deficient and TNF receptor p55--deficient mice compared with wild-type mice. Overall, these studies demonstrate that TNF, released after allergen challenge, is important in the induction of endothelial cell adhesiveness, a prerequisite for recruitment of circulating eosinophils.

Eotaxin induces a sustained reduction in the functional adhesive state of very late antigen 4 for the connecting segment 1 region of fibronectin

BACKGROUND

Eosinophils that have bound to extracellular matrix proteins, such as the connecting segment 1 (CS-1) region of fibronectin, need to deadhere before undergoing chemotaxis through the extracellular matrix.

OBJECTIVE

We have investigated whether eotaxin can regulate the strength of eosinophil adhesion to the CS-1 region of fibronectin.

METHODS

We have used a micropipette single-cell adhesion assay to determine the force of eosinophil adhesion to the CS-1 region of fibronectin.

RESULTS

Eosinophils bound to CS-1 with high avidity, and this binding could be inhibited with neutralizing antibodies to alpha4 integrins expressed by eosinophils or with neutralizing antibodies to CS-1. Eosinophils incubated in the presence of eotaxin demonstrated a transient increase in the force of eosinophil adhesion to CS-1, which was followed by a more sustained reduction in the force of eosinophil adhesion to CS-1, as assessed in the micropipette single-cell adhesion assay. This decreased binding of eosinophils to CS-1 was not due to alterations in very late antigen 4 (VLA-4) receptor number, as assessed with FACS analysis, or alterations in VLA-4 receptor distribution, as assessed with immunofluorescence microscopy.

CONCLUSIONS

These studies suggest that eotaxin can cause a transient increase followed by a more sustained reduction in the functional force of VLA-4 adhesion to CS-1 and thus promote deadhesion of CS-1 adherent eosinophils in the extracellular matrix.

VCAM-1 is more effective than MAdCAM-1 in supporting eosinophil rolling under conditions of shear flow

The ability of the alpha4 integrin counterligands vascular cell adhesion molecule (VCAM)-1 or mucosal addressin (MAd)CAM-1 to support eosinophil rolling or firm adhesion under conditions of physiologic flow has not been delineated. Using a parallel plate flow chamber in vitro and intravital microscopy in vivo, we demonstrate that eosinophil rolling and adhesion on VCAM-1 is mediated by both alpha4beta1 and alpha4beta7 integrins. Eosinophils rolled equally efficiently on both VCAM-1 2 domain and VCAM-1 7 domain, suggesting that the N-terminal 2 domains of VCAM-1 are sufficient to support eosinophil rolling under conditions of flow. Furthermore, activation of the eosinophil beta1 integrin with monoclonal antibody (mAb) 8A2 resulted in both resistance to shear stress-induced detachment from VCAM-1 in vitro and in stable arrest of rolling eosinophils on interleukin (IL)-1beta-stimulated venules in vivo. Eosinophils rolled less efficiently on MAdCAM-1- than on VCAM-1-coated coverslips under conditions of flow. However, eosinophils firmly adhered as efficiently to MAdCAM-1 as to VCAM-1. Overall, these results demonstrate that both VCAM-1 and MAdCAM-1 can support eosinophil firm adhesion under conditions of flow. In contrast, VCAM-1 is significantly more efficient than MAdCAM-1 in supporting eosinophil rolling under conditions of flow. (Blood. 2000;95:592-601)

Patient housing options as viewed by parents of the mentally ill. Housing Committee, California Alliance for the Mentally Ill

The housing committee of the California Alliance for the Mentally Ill, an organization of parents of mentally ill adults, surveyed 350 members on the housing needs of their sons and daughters. The parents reported that their offspring had a high degree of residential instability, and parents expressed the need for wider choices in housing options and more vocational and rehabilitation programs. Parents reported that patients were most satisfied with living at home or in semi-independent living situations and least satisfied with living on the streets or in state hospitals.