Herpes simplex virus immediate-early ICP0 protein inhibits Toll-like receptor 2-dependent inflammatory responses and NF-kappaB signaling.

The discovery of the Toll-like receptors (TLRs) and their importance in the regulation of host responses to infection raised attention to the complex interplay between viral gene products and the host innate immune responses in determining the outcome of virus infection. Robust inflammatory cytokine responses are observed in herpes simplex virus (HSV)-infected animals and cells. Our studies have demonstrated that Toll-like receptor 2 (TLR2) activation by HSV results in NF-κB activation with concomitant inflammatory cytokine production and that TLR2 activation plays a critical role in HSV-induced pathology and mortality. Here we demonstrate that the HSV-1 immediate-early ICP0 protein reduces the TLR2-mediated inflammatory response to HSV 1 (HSV-1) infection. Expression of ICP0 alone is sufficient to block TLR2-driven responses to both viral and nonviral ligands at or downstream of the MyD88 adaptor and upstream of p65. ICP0 alone can also reduce the levels of MyD88 and Mal (TIRAP). In HSV-infected cells, the E3 ligase function of ICP0 and cellular proteasomal activity are required for the inhibitory activity. Our results argue for a model in which ICP0 promotes the degradation of TLR adaptor molecules and inhibition of the inflammatory response, much as it inhibits the interferon response by sequestration and degradation of interferon regulatory factor 3 (IRF-3).

Core outcome set measurement for future clinical trials in acute myeloid leukemia: the HARMONY study protocol using a multi-stakeholder consensus-based Delphi process and a final consensus meeting.

BACKGROUND: Acute myeloid leukemia (AML) is the most common acute leukemia in adults and has an unacceptably low cure rate. In recent years, a number of new treatment strategies and compounds were developed for the treatment of AML. There were several randomized controlled clinical trials with the objective to improve patients' management and patients' outcome in AML. Unfortunately, these trials are not always directly comparable since they do not measure the same outcomes, and currently there are no core outcome sets that can be used to guide outcome selection and harmonization in this disease area. The HARMONY (Healthcare Alliance for Resourceful Medicine Offensive against Neoplasms in Hematology) Alliance is a public-private European network established in 2017 and currently includes 53 partners and 32 associated members from 22 countries. Amongst many other goals of the HARMONY Alliance, Work Package 2 focuses on defining outcomes that are relevant to each hematological malignancy. Accordingly, this pilot study will be performed to define a core outcome set in AML. METHODS: The pilot study will use a three-round Delphi survey and a final consensus meeting to define a core outcome set. Participants will be recruited from different stakeholder groups, including patients, clinicians, regulators and members of the European Federation of Pharmaceutical Industries and Associations. At the pre-Delphi stage, a literature research was conducted followed by several semi-structured interviews of clinical public and private key opinion leaders. Subsequently, the preliminary outcome list was discussed in several multi-stakeholder face-to-face meetings. The Delphi survey will reduce the preliminary outcome list to essential core outcomes. After completion of the last Delphi round, a final face-to-face meeting is planned to achieve consensus about the core outcome set in AML. DISCUSSION: As part of the HARMONY Alliance, the pilot Delphi aims to define a core outcome set in AML on the basis of a multi-stakeholder consensus. Such a core outcome set will help to allow consistent comparison of future clinical trials and real-world evidence research and ensures that appropriate outcomes valued by a range of stakeholders are measured within future trials.

Camelpox virus encodes a schlafen-like protein that affects orthopoxvirus virulence.

Camelpox virus (CMLV) gene 176R encodes a protein with sequence similarity to murine schlafen (m-slfn) proteins. In vivo, short and long members of the m-slfn family inhibited T-cell development, whereas in vitro, only short m-slfns caused arrest of fibroblast growth. CMLV 176 protein (v-slfn) is most closely related to short m-slfns; however, when expressed stably in mammalian cells, v-slfn did not inhibit cell growth. v-slfn is a predominantly cytoplasmic 57 kDa protein that is expressed throughout infection. Several other orthopoxviruses encode v-slfn proteins, but the v-slfn gene is fragmented in all sequenced variola virus and vaccinia virus (VACV) strains. Consistent with this, all 16 VACV strains tested do not express a v-slfn detected by polyclonal serum raised against the CMLV protein. In the absence of a small animal model to study CMLV pathogenesis, the contribution of CMLV v-slfn to orthopoxvirus virulence was studied via its expression in an attenuated strain of VACV. Recombinant viruses expressing wild-type v-slfn or v-slfn tagged at its C terminus with a haemagglutinin (HA) epitope were less virulent than control viruses. However, a virus expressing v-slfn tagged with the HA epitope at its N terminus had similar virulence to controls, implying that the N terminus has an important function. A greater recruitment of lymphocytes into infected lung tissue was observed in the presence of wild-type v-slfn but, interestingly, these cells were less activated. Thus, v-slfn is an orthopoxvirus virulence factor that affects the host immune response to infection.

The human adaptor SARM negatively regulates adaptor protein TRIF-dependent Toll-like receptor signaling.

Toll-like receptors discriminate between different pathogen-associated molecules and activate signaling cascades that lead to immune responses. The specificity of Toll-like receptor signaling occurs by means of adaptor proteins containing Toll-interleukin 1 receptor (TIR) domains. Activating functions have been assigned to four TIR adaptors: MyD88, Mal, TRIF and TRAM. Here we characterize a fifth TIR adaptor, SARM, as a negative regulator of TRIF-dependent Toll-like receptor signaling. Expression of SARM blocked gene induction 'downstream' of TRIF but not of MyD88. SARM associated with TRIF, and 'knockdown' of endogenous SARM expression by interfering RNA led to enhanced TRIF-dependent cytokine and chemokine induction. Thus, the fifth mammalian TIR adaptor SARM is a negative regulator of Toll-like receptor signaling.