NGF induces activation of caspase-1 through NLRP1/NLRP3 inflammasomes in monocytic cell line.

<p><b>(A)</b> Magnetically sorted human monocytes (n = 8) were cultured 24 hrs with NGF (100 ng/ml) and activated caspase-1 was determined using FLICA kit. Representative immunofluorescent images (20x, Leica Microscope) showing more FLICA⁺ positive monocytes in NGF treated culture compared to untreated. <b>(B)</b> Monocytes cultured in similar settings with FLICA were subjected to flow cytometry to determine activated caspase-1 using FlowJo. First representative histogram is the stain-1 for FLICA using PI^- cells. NGF treatment showed more FLICA⁺ monocytes compared to untreated control. <b>(C)</b> Real-time PCR was done with extracted total RNA from null THP-1 cells cultured 24 hrs with or without NGF (100 ng/ml), K252a (100 ng/ml), PLX7486 (100 ng/ml) and PDTC (50 μM). 18S rRNA was used as an endogenous control. NGF significantly upregulated mRNA of NLRP1, which is effectively blocked by K252a, PLX7486 and PDTC (n = 6). <b>(D)</b> In similar setting, NGF/TrkA interaction significantly upregulated mRNA of NLRP3 in a NF-κB dependent manner (n = 6). Data expressed as Mean ± SEM. Mann Whitney U test was done to determine statistical significance.