Biology subjects

Pontillo, A.

Publications and source records attributed to Pontillo, A..

3 recordsLinked to original sources

bioRxiv2024

BTK and MMP9 regulate NLRP3 inflammasome-dependent cytokine and NET responses in primary neutrophils.

BackgroundInflammation is a double-edged state of immune activation that is required to resolve threats harmful to the host but can also cause severe collateral damage. Polymorphonuclear neutrophils (PMN,) the primary leukocyte population in humans, mediate inflammation through the release of cytokines and neutrophil extracellular traps (NETs). Whilst the pathophysiological importance of NETs is unequivocal, the multiple molecular pathways driving NET release are not fully defined. Recently, NET release was linked to the NLRP3 inflammasome which is regulated by Brutons tyrosine kinase (BTK) in macrophages. ObjectiveAs NLRP3 inflammasome regulation by BTK has not been studied in neutrophils, we here explored a potential regulatory role of BTK in primary murine and human neutrophils and matched monocytes or macrophages from Btk-deficient vs WT mice or healthy donors (HD) vs BTK deficient X-linked agammaglobulinemia (XLA) patients, respectively. MethodsCytokine, MPO and MMP-9 release were quantified by ELISA, NET release and inflammasome formation by immunofluorescence. ResultsSurprisingly, in both mouse and human primary neutrophils, we observed a significant increase in NLRP3 inflammasome-dependent IL-1{beta} and NETs when BTK was absent or inhibited, whereas IL-1{beta} release was decreased in corresponding primary mouse macrophages or human PBMC, respectively. This suggests a negative regulatory role of BTK in neutrophil NLRP3 activation. Both IL-1{beta} and NET release in mouse and human primary neutrophils were strictly dependent on NLRP3, caspase-1 and, surprisingly, MMP-9. ConclusionThis highlights BTK and MMP-9 as novel and versatile inflammasome regulators and may have implications for the clinical use of BTK inhibitors. Key messagesO_LINeutrophils contribute to inflammation by release of interleukin-1{beta} and Neutrophil Extracellular Traps (NETs) via the NLRP3 inflammasome C_LIO_LIBrutons tyrosine kinase (BTK) is a negative regulator of NLRP3-mediated primary human neutrophil functions, whereas it positively regulates NLRP3 in monocytes C_LIO_LIMMP-9 is both effector and regulator of the neutrophil NLRP3 inflammasome C_LI Capsule summaryHere we report that interleukin-1{beta} and Neutrophil Extracellular Traps (NETs) release via the NLRP3 inflammasome is negatively regulated by Brutons tyrosine kinase (BTK) in primary neutrophils. Thus, targeting BTK using FDA-approved inhibitors might increase neutrophil functions. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/581733v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@482a15org.highwire.dtl.DTLVardef@1c2f1e0org.highwire.dtl.DTLVardef@195c2a5org.highwire.dtl.DTLVardef@11e1af2_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

NLRP3 and NLRP1/CARD8 pathways differently contribute to pyroptosis of CD8+ T cells of ART-treated HIV patients

HIV-infected (HIV) patients exhibit immune dysregulation independently of antiretroviral therapy. The inflammasome, a cytosolic complex responsible for cleavage of the inflammatory cytokines IL -1{beta} and IL -18 and pyroptosis, is highly activated in peripheral blood mononuclear cells of HIV patients, suggesting its involvement in leukocyte dysfunction. While monocytes, B cells, and CD4+ T cells have been studied, little is known about CD8+ T lymphocytes. Therefore, we proposed to characterize the inflammasome activation in these cells, both the NLRP3 and NLRP1/CARD8 pathways, which are partially described in T cells. CD8+ T lymphocytes from non-HIV healthy donors (HD) and HIV patients were analyzed ex vivo and stimulated in vitro with known activators of NLRP3 (-CD3/-CD28), NLRP1 and CARD8 (DPP9 inhibitor ValboroPro, VbP) to assess inflammasome activation. HIV CD8+ T cells present a constitutively activated caspase-1 which positively correlates with the cell activation state. HIV CD8+ T cells were more activated and more resistant to VbP-induced pyroptosis than HD. On the other way, HIV CD8+ T lymphocytes showed higher pyroptosis in response to -CD3/-CD28. These findings suggest that the NLRP3 pathway is significantly dysregulated in those patients, and TCR stimulation may result in cell loss. At the same time, being HIV CD8+ T cells constitutively activated, other inflammasome pathways, such as NLRP1 or CARD8, present a delayed activation.

immunology↗

bioRxiv2020

Sensing soluble uric acid by Naip1-Nlrp3 platform

The immune system can recognize microbes and sterile tissue damage. Among the damage-associated molecular patterns (DAMPs), uric acid is considered a major component which can trigger inflammation. It represents a breakpoint in the evolutionary history of humans as our ancestors lost the uricase gene, the enzyme responsible for its cleavage. High soluble uric acid (sUA) concentration is able to increase IL-1{beta} in murine, but not human macrophages. We observed that sUA increased the mRNA expression of Naip1 in murine macrophages, and, therefore, we hypothesized that the recognition of sUA can be made by a Naip1-Nlrp3 inflammasome platform. Additionally, we used genome-wide transcriptome analysis, functional analyses and structural modeling predictions and observed that virus-transduction of murine Naip1 into human macrophages induced IL-1{beta} after sUA stimulus, besides leading to fatty acid production and an inflammation-related response. Moreover, pharmacologic inhibition and genetic loss of Nlrp3 led to decreased IL-1{beta} production upon sUA stimulus. Surface plasmon resonance and quartz crystal microbalance showed that sUA is able to interact with Naip1. Naip could be a lost receptor for sUA in the evolutionary process and a better understanding of the immune modulatory function of sUA could lead to design rational novel anti-hyperuricemic therapies.

immunology↗