α-Linoleic Acid Enhances the Capacity of α1-Antitrypsin to Inhibit Lipopolysaccharide-Induced IL-1β in Human Blood Neutrophils

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Abstract

<p class="first" id="d16549505e185">Alpha1-antitrypsin (A1AT, SERPINA1), a major circulating inhibitor of neutrophil elastase (NE) and proteinase-3 (PR3), has been proposed to reduce the processing and release of IL-1β. Since the antiinflammatory properties of A1AT are influenced by the presence of polyunsaturated fatty acids, we compared the effects of fatty acid–free (A1AT-0) and α-linoleic acid (LA)–bound (A1AT-LA) forms of A1AT) on lipopolysaccharide (LPS)-induced synthesis of the IL-1β precursor and the release of IL-1β from human blood neutrophils. The presence of A1AT-LA or A1AT-0 significantly reduced LPS-induced release of mature IL-1β. However, only A1AT-LA reduced both steady-state mRNA levels of IL-1β and the secretion of mature IL-1β. In LPS-stimulated neutrophils, mRNA levels of TLR2/4, NFKBIA, P2RX7, NLRP3, and CASP1 decreased significantly in the presence of A1AT-LA but not A1AT-0. A1AT-0 and A1AT-LA did not inhibit the direct enzymatic activity of caspase-1, but we observed complexes of either form of A1AT with NE and PR3. Consistent with the effect on TLR and IL-1β gene expression, only A1AT-LA inhibited LPS-induced gene expression of NE and PR3. Increased gene expression of peroxisome proliferator-activated receptor (PPAR)-γ was observed in A1AT-LA–treated neutrophils without LPS stimulation, and the selective PPAR-γ antagonist (GW9662) prevented a reduction in IL-1β by A1AT-LA. We conclude from our data that the ability of A1AT to reduce TLR and IL-1β gene expression depends on its association with LA. Moreover, the antiinflammatory properties of A1AT-LA are likely to be mediated by activation of PPARγ. </p>

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Neutrophil recruitment and function in health and inflammation.

Elzbieta Kolaczkowska, Paul Kubes (2013)

Neutrophils have traditionally been thought of as simple foot soldiers of the innate immune system with a restricted set of pro-inflammatory functions. More recently, it has become apparent that neutrophils are, in fact, complex cells capable of a vast array of specialized functions. Although neutrophils are undoubtedly major effectors of acute inflammation, several lines of evidence indicate that they also contribute to chronic inflammatory conditions and adaptive immune responses. Here, we discuss the key features of the life of a neutrophil, from its release from bone marrow to its death. We discuss the possible existence of different neutrophil subsets and their putative anti-inflammatory roles. We focus on how neutrophils are recruited to infected or injured tissues and describe differences in neutrophil recruitment between different tissues. Finally, we explain the mechanisms that are used by neutrophils to promote protective or pathological immune responses at different sites.

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The NF-kappaB family of transcription factors and its regulation.

Andrea Oeckinghaus, Sankar K Ghosh (2009)

Nuclear factor-kappaB (NF-kappaB) consists of a family of transcription factors that play critical roles in inflammation, immunity, cell proliferation, differentiation, and survival. Inducible NF-kappaB activation depends on phosphorylation-induced proteosomal degradation of the inhibitor of NF-kappaB proteins (IkappaBs), which retain inactive NF-kappaB dimers in the cytosol in unstimulated cells. The majority of the diverse signaling pathways that lead to NF-kappaB activation converge on the IkappaB kinase (IKK) complex, which is responsible for IkappaB phosphorylation and is essential for signal transduction to NF-kappaB. Additional regulation of NF-kappaB activity is achieved through various post-translational modifications of the core components of the NF-kappaB signaling pathways. In addition to cytosolic modifications of IKK and IkappaB proteins, as well as other pathway-specific mediators, the transcription factors are themselves extensively modified. Tremendous progress has been made over the last two decades in unraveling the elaborate regulatory networks that control the NF-kappaB response. This has made the NF-kappaB pathway a paradigm for understanding general principles of signal transduction and gene regulation.