Isoform localization of Dectin‐1 regulates the signaling quality of anti‐fungal immunity

Abstract

Dectin-1 is recognized as a major receptor for fungal ß-glucans and contributes to anti-fungal immunity. Human monocyte populations express Dectin-1 isoforms A and B, which differ by the presence of a stalk region and its N-linked glycosylation site. Here, we analyzed the expression of both isoforms in human monocyte-derived cells. The cellular localization on cell lines stably expressing either Dectin-1 isoform A or B was studied by flow cytometry and confocal laser scanning microscopy. Intracellular protein signaling and cytokine production were analyzed by immunoblotting and cytometric bead array, respectively. Monocyte-derived cells showed cell type-specific expression of the two isoforms. Glycosylated Dectin-1 isoform A was predominantly localized at the cell surface, non-glycosylated isoform B was retained intracellularly. Inhibition of glycosylation resulted in efficient abrogation of cell surface expression of isoform A. Signaling quality following Dectin-1 stimulation was reduced in isoform B cells. Differential isoform specific cytokine secretion was observed by cytometric bead array. We show here that n-glycosylation of Dectin-1 is crucial for its cell surface expression and consequently signal transduction. Taken together, unique cytokine secretion and varying expression levels of human Dectin-1 isoforms on monocyte-derived cells may indicate distinct isoform usage as a cell type-specific mechanism of regulating anti-fungal immunity.

HemITAM: A single tyrosine motif that packs a punch

“…Upon maturation of monocytes, the abundance of isoform B increased, whereas the abundance of isoform A decreased. Both isoforms seem to differ with regard to their subcellular localization and cytokine secretion profile (67).…”

RHOA mediated mechanical force generation through Dectin-1

“…1b). To further test our hypothesis in a system chosen for physiological relevance, we performed similar experiments in M1 macrophages differentiated from human peripheral blood monocytes 13,23,24 . Areal contraction similar to that observed with Dectin-1 expressing HEK-293 cells was also observed in M1 macrophages ( Fig.…”

“…De-identified Primary Peripheral Blood Mononuclear Cells (PBMC) (ATCC, #PCS-800-011) were thawed and cultured using Roswell Park Memorial Institute (RPMI) 1640 medium, 10% FBS, 1% Penicillin-Streptomycin, 2 mM L-glutamine, 1 mM Sodium pyruvate medium at 37°, 5% CO 2 environment in incubator 38 . For generation of M1 macrophages, 50 ng/mL rhGM-CSF (PeproTech, #300-03) was added to culture dish for 7 days followed by stimulation with 500 ng/mL LPS (Invivogen, #tlrl-peklps) for 24 hours 24,38 . Contractility assay.…”

Host Genetic Signatures of Susceptibility to Fungal Disease

“…This functional axis is further demonstrated by primary immunodeficiencies due to rare mutations in STAT3, IL-17RA and IL-17F that impair Th17 immunity and are associated with CMC and aspergillosis (Lionakis and Levitz 2018). Because the cellular localization of the different dectin-1 isoforms regulates the signaling quality of antifungal immunity (Carvalho et al 2012c;Fischer et al 2017), it is also tempting to speculate that this may be one additional mechanism through which the Y238X variant may contribute to infection. Of note, another non-synonymous variant in dectin-1 (rs16910527; I223S) was instead associated with lower levels of interferon (IFN)-c and the risk of oropharyngeal candidiasis in HIV patients (Plantinga et al 2010).…”