The objective was to assess outcomes of IFNγ-priming upon macrophage activation by the synovial macromolecule high-molecular-weight hyaluronan [HMW-HA] in the context of rheumatoid arthritis inflammation. Human macrophages primed by IFNγ and activated by HMW-HA were evaluated for cytokine secretion by ELISA and Milliplex assay and activation profiles by nuclear transcription factor EIA. IFNγ-primed, HMW-HA-activated macrophages produced elevated levels of TNF and secreted the TH1 cytokine IL-12p70, while IFNγ suppressed HMW-HA-induced secretion of the regulatory cytokine IL-10 and activation of the transcription factor c-Jun. IFNγ modulates the HMW-HA-induced cytokine response profile promoting macrophage activation and inflammatory TH1 cytokine secretion.

Nelfinavir has anti‐inflammatory effects directly upon human macrophages independent of antiviral activity.

HIV-1-associated innate immune activation is caused by viral replication and/or microbial substances that leak from the gut lumen into the circulation (microbial translocation). Consequences of the ensuing HIV-1-associated inflammation range from neurocognitive impairment to cardiovascular disease where macrophages play a central role. HIV-1 therapy is evaluated based on suppression of viremia and restoration of CD4 T cells, while the effects of therapy on innate immune activation are rarely considered. The current study assessed the effects of protease inhibitors on macrophage activation ex vivo and in vivo. Nelfinavir [NFV] and tipranavir [TPV] inhibited LPS activation of human macrophages ex vivo as measured by reduced secretion of LPS-binding protein soluble CD14 [sCD14] and pro-inflammatory cytokines IL-6 and TNF. Cytokine secretion was inhibited prior to transcription by modulation of toll-like receptor signaling pathways. In vivo, NFV-treated HIV-1-infected patients presented with significantly reduced monocyte/macrophage activation as measured by a greater reduction in sCD14 plasma levels compared to those treated with indinavir or ritonavir. These data suggest that anti-inflammatory effects of NFV or TPV may augment efficacy of HIV-1 treatment by targeting HIV-1-assocated innate immune activation. Delineation of cellular targets of NFV or TPV will lead to novel approaches to suppress innate immune activation in HIV-1, other infectious diseases or autoimmunity.

No abstract

Rheumatoid arthritis [RA] is caused in part by cytokines secreted by classically activated synovial macrophages. We reported that IFNγ, typically produced by CD4 T cells within synovitis, primes macrophages for activation by high molecular weight hyaluronan [HMW-HA], a major component of joint synovial fluid. HMW-HA is a ligand for both toll-like receptor 4 [TLR4] and CD44. The purpose of this study was to compare the molecular mechanism of HMW-HA (endogenous TLR ligand) versus LPS (exogenous TLR ligand) induced macrophage activation. Transcriptome bioprofiles were determined by cDNA arrays, and the roles of CD44 and TLR4 were determined using blocking antibodies and cytokine measurement by Milliplex®. Significant differences in gene expression profiles were revealed when comparing IFNγ priming versus mock priming under both LPS and HMW-HA activating conditions, although nearly identical gene expression profiles were observed when comparing HMW-HA to LPS stimulation under both mock and IFNγ priming conditions. Blockade of CD44 enhanced inflammatory cytokine secretion while blockade of TLR4 inhibited inflammatory cytokine secretion in response to either HMW-HA or LPS. HMW-HA provides the stimulus required for classical macrophage activation when cells are primed with IFNγ in a response that is essentially identical to the LPS response. Type 1 T cells in proximity to endogenous TLR ligands may provide sufficient signals to initiate classical macrophage activation in RA.