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Recent documents in eScholarship@UMMS
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Cytoplasmic HIV-1 RNA is mainly transported by diffusion in the presence or absence of Gag protein

Thu, 12/11/2014 - 10:38am

Full-length HIV-1 RNA plays a central role in viral replication by serving as the mRNA for essential viral proteins and as the genome packaged into infectious virions. Proper RNA trafficking is required for the functions of RNA and its encoded proteins; however, the mechanism by which HIV-1 RNA is transported within the cytoplasm remains undefined. Full-length HIV-1 RNA transport is further complicated when group-specific antigen (Gag) protein is expressed, because a significant portion of HIV-1 RNA may be transported as Gag-RNA complexes, whose properties could differ greatly from Gag-free RNA. In this report, we visualized HIV-1 RNA and monitored its movement in the cytoplasm by using single-molecule tracking. We observed that most of the HIV-1 RNA molecules move in a nondirectional, random-walk manner, which does not require an intact cytoskeletal structure, and that the mean-squared distance traveled by the RNA increases linearly with time, indicative of diffusive movement. We also observed that a single HIV-1 RNA molecule can move at various speeds when traveling through the cytoplasm, indicating that its movement is strongly affected by the immediate environment. To examine the effect of Gag protein on HIV-1 RNA transport, we analyzed the cytoplasmic HIV-1 RNA movement in the presence of sufficient Gag for virion assembly and found that HIV-1 RNA is still transported by diffusion with mobility similar to the mobility of RNAs unable to express functional Gag. These studies define a major mechanism of HIV-1 gene expression and resolve the long-standing question of how the RNA genome is transported to the assembly site.

Making Women's Health Connections: Between Researchers and to Resources

Wed, 12/10/2014 - 8:03am

The Lamar Soutter Library at the University of Massachusetts Medical School has recently completed the second year of a National Library of Medicine grant funded project; the Women’s Health Resources Dissemination Outreach Project. The goals include assisting women’s health researchers by providing them with access to information and making them more aware of opportunities and available resources. This, ultimately, enables both an improvement in women’s health and the advancement of women in academic medicine. Moreover, by supporting women’s health research and women researchers through the objectives of this project, women researchers build connections, knowledge, and skills. This facilitates meaningful contributions and fosters greater promotion and leadership opportunities for these women. This poster describes the goals, activities, and progress of the project through the completion of the second year. Specific programs and initiatives are highlighted. This includes the multi-year endeavor to build, recruit, and showcase women’s health researchers in a specific collection of eScholarship@UMMS, the library’s institutional repository. Promotion and outreach, of both the project and the resources, was major component of the second year. Additionally, programming was developed that helped researchers better communicate their work to the media and public. Other programs, lessons learned, successes, and future goals are noted.

Nutrition and Cancer

Tue, 12/09/2014 - 11:10am

This chapter in Cancer Concepts: A Guidebook for the Non-Oncologist presents a summary of the nutritional concerns in oncology patients. Nutritional intake is frequently deficient in patients undergoing cancer treatment and should be assessed and treated. There are unique nutritional needs of the patient based on their site of cancer and effects of their particular treatment. There is little evidence that dietary manipulation or supplementation can produce a significant decrease in cancer risk.

Systematic Review of Evidence of Interventions Addressing Disparities in Oral Health for Adults with Intellectual Disabilities: Year 2

Tue, 12/09/2014 - 10:20am

Preventive oral health care and treatment for individuals with an intellectual or developmental disability (I/DD) is a leading public health disparity. Evidence points to poorer oral hygiene, higher prevalence and greater severity of periodontal disease, as well as a higher incidence of untreated caries in the I/DD population. In year 1 of this systematic review, the literature was searched and screened for inclusion, developing an extensive database of interventions to increase access and behavioral oral health interventions for individuals with I/DD. The objective of year 2 of the systematic review is to examine this literature in depth. Data review and assessment will be conducted in an electronic repository. Incorporating a public health approach, including social, personal and environmental factors, the team will assess, sort and summarize the interventions, providing a better understanding of common themes. Expert clinicians and methodologists will conduct an assessment of the evidence with a consideration of the execution, design suitability, number of studies available, consistency of findings, effect size, and whether expert opinion was used. In addition, findings resulting from a lack of evidence due to poor study design, small sample size, inconsistent findings, small effect sizes, or other limitations in the study will be identified and catalogued. Reviewed findings will be synthesized to identify effective interventions to reduce oral health disparities in adults with I/DD. These findings will be presented, in addition to a catalogue of promising interventions that have yet to be demonstrated but nevertheless are viewed as promising approaches to reduce disparities.

Sites and artifacts related to Horace Wells in Hartford, Connecticut

Mon, 12/08/2014 - 4:52pm

Horace Wells, a contender for recognition as the discoverer of anesthesia, is celebrated in the town where he conducted most of his work, Hartford, CT. His only descendant was his son, Charles Thomas Wells (1839-1909), an influential and successful business executive at Aetna Insurance Company. He was a man of considerable influence, and he worked tirelessly with city officials and the Connecticut Dental Association in celebrating the 50th anniversary of his father's contribution to medicine. This discovery is unique because events and individuals in 1 country, the United States, contributed entirely to the birth of a medical specialty. Sites in Jefferson, GA; Hartford, CT; and Boston, MA and their environs celebrate this most precious contribution to modern medicine, especially since the introduction of safe anesthesia permitted the development of surgical specialties and obstetrics. We trace the history and relationship between Horace Wells and several sites and artifacts in Hartford, CT. These sites span the most important, distinctive, and attractive parts of the city: Bushnell Park, Trinity College, Cedar Hill Cemetery, the Athenaeum, and the Connecticut Historical Society.

Alternate methods to teach history of anesthesia

Mon, 12/08/2014 - 4:51pm

Residency programs in anesthesiology in the United States struggle to balance the conflicting needs of formal didactic sessions, clinical teaching, and clinical service obligations. As a consequence of the explosion in knowledge about basic and applied sciences related to our specialty, residents and fellows are expected to make substantial efforts to supplement formal lectures with self-study. There is strong evidence to suggest that members of the younger generation use nontraditional methods to acquire information. Although training programs are not required to include topics related to history of anesthesia (HOA) in the didactic curriculum, and despite the fact that such knowledge does not directly impact clinical care, many programs include such lectures and discussions. We describe and discuss our experience with 3 alternate modalities of teaching HOA.First, we provide brief descriptions of HOA-related historical narratives and novels within the domain of popular literature, rather than those that might be considered textbooks. Second, we analyze content in movies and videodiscs dealing with HOA and determine their utility as educational resources. Third, we describe HOA tours to sites in close proximity to our institutions, as well as those in locations elsewhere in the United States and abroad.We suggest that informal HOA teaching can be implemented by every residency program without much effort and without taking away from the traditional curriculum. Participating in this unique and enriching experience may be a means of academic advancement. It is our hope and expectation that graduates from programs that incorporate such exposure to HOA become advocates of history and may choose to devote a part of their academic career toward exploration of HOA.

Malaria-induced NLRP12/NLRP3-dependent caspase-1 activation mediates inflammation and hypersensitivity to bacterial superinfection

Mon, 12/08/2014 - 4:39pm

Cyclic paroxysm and high fever are hallmarks of malaria and are associated with high levels of pyrogenic cytokines, including IL-1beta. In this report, we describe a signature for the expression of inflammasome-related genes and caspase-1 activation in malaria. Indeed, when we infected mice, Plasmodium infection was sufficient to promote MyD88-mediated caspase-1 activation, dependent on IFN-gamma-priming and the expression of inflammasome components ASC, P2X7R, NLRP3 and/or NLRP12. Pro-IL-1beta expression required a second stimulation with LPS and was also dependent on IFN-gamma-priming and functional TNFR1. As a consequence of Plasmodium-induced caspase-1 activation, mice produced extremely high levels of IL-1beta upon a second microbial stimulus, and became hypersensitive to septic shock. Therapeutic intervention with IL-1 receptor antagonist prevented bacterial-induced lethality in rodents. Similar to mice, we observed a significantly increased frequency of circulating CD14(+)CD16(-)Caspase-1(+) and CD14(dim)CD16(+)Caspase-1(+) monocytes in peripheral blood mononuclear cells from febrile malaria patients. These cells readily produced large amounts of IL-1beta after stimulation with LPS. Furthermore, we observed the presence of inflammasome complexes in monocytes from malaria patients containing either NLRP3 or NLRP12 pyroptosomes. We conclude that NLRP12/NLRP3-dependent activation of caspase-1 is likely to be a key event in mediating systemic production of IL-1beta and hypersensitivity to secondary bacterial infection during malaria.

Interleukin-17-producing innate lymphoid cells and the NLRP3 inflammasome facilitate obesity-associated airway hyperreactivity

Mon, 12/08/2014 - 4:39pm

Obesity is associated with the development of asthma, which is often difficult to control. To understand the immunological pathways that lead to obesity-associated asthma, we fed mice a high-fat diet for 12 weeks, which resulted in obesity and the development of airway hyperreactivity (AHR), a cardinal feature of asthma. This AHR was independent of adaptive immunity, as it occurred in obese Rag1(-/-) mice, which lack B and T cells, and was dependent on interleukin-17A (IL-17A) and the NLRP3 inflammasome, as it did not develop in obese Il17a(-/-) or Nlrp3(-/-) mice. AHR was also associated with the expansion of CCR6(+) type 3 innate lymphoid cells (ILCs) producing IL-17A (ILC3 cells) in the lung, which could by themselves mediate AHR when adoptively transferred into Rag2(-/-); Il2rg(-/-) mice treated with recombinant IL-1beta. Macrophage-derived IL-1beta production was induced by HFD and expanded the number of lung ILC3 cells. Blockade of IL-1beta with an IL-1 receptor antagonist abolished obesity-induced AHR and reduced the number of ILC3 cells. As we found ILC3-like cells in the bronchoalveolar lavage fluid of individuals with asthma, we suggest that obesity-associated asthma is facilitated by inflammation mediated by NLRP3, IL-1beta and ILC3 cells.

Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection

Mon, 12/08/2014 - 4:39pm

Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-alpha/beta receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.

Antiviral autophagy restrictsRift Valley fever virus infection and is conserved from flies to mammals

Mon, 12/08/2014 - 4:39pm

Autophagy has been implicated as a component of host defense, but the significance of antimicrobial autophagy in vivo and the mechanism by which it is regulated during infection are poorly defined. Here we found that antiviral autophagy was conserved in flies and mammals during infection with Rift Valley fever virus (RVFV), a mosquito-borne virus that causes disease in humans and livestock. In Drosophila, Toll-7 limited RVFV replication and mortality through activation of autophagy. RVFV infection also elicited autophagy in mouse and human cells, and viral replication was increased in the absence of autophagy genes. The mammalian Toll-like receptor adaptor, MyD88, was required for anti-RVFV autophagy, revealing an evolutionarily conserved requirement for pattern-recognition receptors in antiviral autophagy. Pharmacologic activation of autophagy inhibited RVFV infection in mammalian cells, including primary hepatocytes and neurons. Thus, autophagy modulation might be an effective strategy for treating RVFV infection, which lacks approved vaccines and therapeutics.

Dual engagement of the NLRP3 and AIM2 inflammasomes by plasmodium-derived hemozoin and DNA during malaria

Mon, 12/08/2014 - 4:39pm

Hemozoin (Hz) is the crystalline detoxification product of hemoglobin in Plasmodium-infected erythrocytes. We previously proposed that Hz can carry plasmodial DNA into a subcellular compartment that is accessible to Toll-like receptor 9 (TLR9), inducing an inflammatory signal. Hz also activates the NLRP3 inflammasome in primed cells. We found that Hz appears to colocalize with DNA in infected erythrocytes, even before RBC rupture or phagolysosomal digestion. Using synthetic Hz coated in vitro with plasmodial genomic DNA (gDNA) or CpG oligodeoxynucleotides, we observed that DNA-complexed Hz induced TLR9 translocation, providing a priming and an activation signal for inflammasomes. After phagocytosis, Hz and DNA dissociate. Hz subsequently induces phagolysosomal destabilization, allowing phagolysosomal contents access to the cytosol, where DNA receptors become activated. Similar observations were made with Plasmodium-infected RBCs. Finally, infected erythrocytes activated both the NLRP3 and AIM2 inflammasomes. These observations suggest that Hz and DNA work together to induce systemic inflammation during malaria.

Rift Valley fever virus infection induces activation of the NLRP3 inflammasome

Mon, 12/08/2014 - 4:39pm

Inflammasome activation is gaining recognition as an important mechanism for protection during viral infection. Here, we investigate whether Rift Valley fever virus, a negative-strand RNA virus, can induce inflammasome responses and IL-1beta processing in immune cells. We have determined that RVFV induces NLRP3 inflammasome activation in murine dendritic cells, and that this process is dependent upon ASC and caspase-1. Furthermore, absence of the cellular RNA helicase adaptor protein MAVS/IPS-1 significantly reduces extracellular IL-1beta during infection. Finally, direct imaging using confocal microscopy shows that the MAVS protein co-localizes with NLRP3 in the cytoplasm of RVFV infected cells.

Long noncoding RNAs in innate and adaptive immunity

Mon, 12/08/2014 - 4:39pm

The differentiation and activation of both innate and adaptive immune cells is highly dependent on a coordinated set of transcriptional and post-transcriptional events. Chromatin-modifiers and transcription factors regulate the accessibility and transcription of immune genes, respectively. Immune cells also express miRNA and RNA-binding proteins that provide an additional layer of regulation at the mRNA level. However, long noncoding RNAs (lncRNAs), which have been primarily studied in the context of genomic imprinting, cancer, and cell differentiation, are now emerging as important regulators of immune cell differentiation and activation. In this review, we provide a brief overview of lncRNAs, their known functions in immunity, and discuss their potential to be more broadly involved in other aspects of the immune response.

The transcriptional repressor BLIMP1 curbs host defenses by suppressing expression of the chemokine CCL8

Mon, 12/08/2014 - 4:39pm

The transcriptional repressor B lymphocyte-induced maturation protein 1 (BLIMP1) is a master regulator of B and T cell differentiation. To examine the role of BLIMP1 in innate immunity, we used a conditional knockout (CKO) of Blimp1 in myeloid cells and found that Blimp1 CKO mice were protected from lethal infection induced by Listeria monocytogenes. Transcriptome analysis of Blimp1 CKO macrophages identified the murine chemokine (C-C motif) ligand 8, CCL8, as a direct target of Blimp1-mediated transcriptional repression in these cells. BLIMP1-deficient macrophages expressed elevated levels of Ccl8, and consequently Blimp1 CKO mice had higher levels of circulating CCL8, resulting in increased neutrophils in the peripheral blood, promoting a more aggressive antibacterial response. Mice lacking the Ccl8 gene were more susceptible to L. monocytogenes infection than were wild-type mice. Although CCL8 failed to recruit neutrophils directly, it was chemotactic for gamma/delta T cells, and CCL8-responsive gamma/delta T cells were enriched for IL-17F. Finally, CCL8-mediated enhanced clearance of L. monocytogenes was dependent on gamma/delta T cells. Collectively, these data reveal an important role for BLIMP1 in modulating host defenses by suppressing expression of the chemokine CCL8.

Recognition of cytosolic DNA by cGAS and other STING-dependent sensors

Mon, 12/08/2014 - 4:39pm

The presence of DNA in the cytoplasm of mammalian cells is perceived as a danger signal, alerting the host to the presence of microbial infection. In response to the detection of cytoplasmic DNA, the immune system mounts a programed response that involves the transcription of anti-viral genes such as type I interferons and production of inflammatory cytokines such as IL-1beta. The recent discovery of the cGAS-cGAMP second messenger pathway as well as IFI16 and additional sensors collectively provide critical insights into the molecular basis behind the sensing of cytoplasmic DNA. The insights obtained from these important discoveries could unveil new avenues to understand host-immunity, improve vaccine adjuvancy, and allow development of new treatments for inflammatory diseases associated with abberrant sensing of DNA.

Unified polymerization mechanism for the assembly of ASC-dependent inflammasomes

Mon, 12/08/2014 - 4:39pm

Inflammasomes elicit host defense inside cells by activating caspase-1 for cytokine maturation and cell death. AIM2 and NLRP3 are representative sensor proteins in two major families of inflammasomes. The adaptor protein ASC bridges the sensor proteins and caspase-1 to form ternary inflammasome complexes, achieved through pyrin domain (PYD) interactions between sensors and ASC and through caspase activation and recruitment domain (CARD) interactions between ASC and caspase-1. We found that PYD and CARD both form filaments. Activated AIM2 and NLRP3 nucleate PYD filaments of ASC, which, in turn, cluster the CARD of ASC. ASC thus nucleates CARD filaments of caspase-1, leading to proximity-induced activation. Endogenous NLRP3 inflammasome is also filamentous. The cryoelectron microscopy structure of ASC(PYD) filament at near-atomic resolution provides a template for homo- and hetero-PYD/PYD associations, as confirmed by structure-guided mutagenesis. We propose that ASC-dependent inflammasomes in both families share a unified assembly mechanism that involves two successive steps of nucleation-induced polymerization. PAPERFLICK:

TRIF signaling is essential for TLR4-driven IgE class switching

Mon, 12/08/2014 - 4:39pm

The TLR4 ligand LPS causes mouse B cells to undergo IgE and IgG1 isotype switching in the presence of IL-4. TLR4 activates two signaling pathways mediated by the adaptor molecules MyD88 and Toll/IL-IR domain-containing adapter-inducing IFN-beta (TRIF)-related adaptor molecule (TRAM), which recruits TRIF. Following stimulation with LPS plus IL-4, Tram(-/-) and Trif(-/-) B cells completely failed to express Cepsilon germline transcripts (GLT) and secrete IgE. In contrast, Myd88(-/-) B cells had normal expression of Cepsilon GLT but reduced IgE secretion in response to LPS plus IL-4. Following LPS plus IL-4 stimulation, Cgamma1 GLT expression was modestly reduced in Tram(-/-) and Trif(-/-) B cells, whereas Aicda expression and IgG1 secretion were reduced in Tram(-/-), Trif(-/-), and Myd88(-/-) B cells. B cells from all strains secreted normal amounts of IgE and IgG1 in response to anti-CD40 plus IL-4. Following stimulation with LPS plus IL-4, Trif(-/-) B cells failed to sustain NF-kappaB p65 nuclear translocation beyond 3 h and had reduced binding of p65 to the Iepsilon promoter. Addition of the NF-kappaB inhibitor, JSH-23, to wild-type B cells 15 h after LPS plus IL-4 stimulation selectively blocked Cepsilon GLT expression and IgE secretion but had little effect on Cgamma1 GLT expression and IgG secretion. These results indicate that sustained activation of NF-kappaB driven by TRIF is essential for LPS plus IL-4-driven activation of the Cepsilon locus and class switching to IgE.