Toll-like receptor-activated human plasmacytoid dendritic cells : mechanisms of acquisition and elicitation of TRAIL-mediated tumoricidal activity

Dendritische Zellen (DZ) besitzen nicht nur die einzigartige Fähigkeit durch die Detektion und Präsentation unbekannter Antigene eine primäre Immunantwort einzuleiten, sondern können auch nach Toll-like Rezeptor (TLR)-vermittelter Aktivierung zytotoxische Moleküle exprimieren. Wir und andere konnten zeigen, dass aus humanem Peripherblut isolierte, TLR7/8- und TLR9-aktivierte plasmazytoide DZs (pDZ) das zytotoxische Molekül tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) an ihrer Oberfläche hochregulieren. Die genauen Mechanismen, durch die pDZs ihre zytotoxische Funktion entwickeln und ausüben, sind jedoch noch nicht hinreichend geklärt. In dieser Studie konnten wir zeigen, dass TRAIL nur durch Liganden von intrazellulären TLR und durch das klassische pDZ Zytokin Interleukin-3 induziert wird. Wir fanden außerdem auch große Mengen an Granzym B in pDZ, nicht jedoch andere lytische Moleküle wie Perforin, Granulysin, Lysozym oder Fas Ligand. In pDZ führte die TLR-induzierte Expression von TRAIL auch zu einer Hochregulierung von kostimulatorischen Molekülen und letztlich zu einer gesteigerten allostimulatorischen Funktion. Die Induktion von TRAIL auf TLR7/8- (Imiquimod, IMQ) und TLR9 (CpG2216)-aktivierten pDZ war Interferon (IFN)-[alpha]/[beta]-abhängig und bemerkenswerterweise konnte IFN-[alpha] alleine TRAIL auf niedrigem Niveau induzieren. Sowohl TLR7/8- als auch TLR9-stimulierte pDZ waren funktionell aktiv und konnten die T Zelllinie Jurkat TRAIL- und Zellkontakt-abhängig lysieren. Wichtiger jedoch war unser Ergebnis, dass auch IFN-[alpha]-stimulierte pDZ Jurkat Zellen im selben Ausmaß lysieren konnten, obwohl sie nicht TLR-aktiviert oder ausgereift waren. Sowohl IMQ- als auch IFN-[alpha]-stimulierte pDZ konnten außerdem auch humane Melanomzelllinien mittels TRAIL töten. Interessanterweise hatten suboptimale IMQ und IFN-[alpha] Dosen synergistische Effekte, die nicht nur zu einer optimalen Expression von TRAIL, sondern auch zu optimaler Zelllyse führten. Zusammenfassend weisen unsere Ergebnisse auf eine mögliche Rolle von zytotoxischen pDZ in der Tumorimmunantwort bei Melanompatienten hin, die IMQ oder IFN-[alpha] als adjuvante Therapie erhalten.Dendritic cells (DCs) do not only exhibit the unique capacity to evoke primary immune responses, but may also acquire Toll-like receptor (TLR)-triggered cytotoxic activity. We and others have previously shown that TLR7/8- and TLR9-stimulated plasmacytoid DCs (pDCs) isolated from human peripheral blood express the effector molecule tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). The exact mechanisms through which pDCs acquire and elicit their cytotoxic activity, however, are still not clear. We now show that TRAIL induction on pDCs occurs with agonists to intracellular TLRs or interleukin-3 only. We also detected large amounts of granzyme B even in unstimulated pDCs, but not other lytic molecules such as granulysin, perforin, lysozyme or Fas ligand. TLR-activation in pDCs was accompanied by a phenotypic as well as functional maturation, as evidenced by a comparatively superior MLR-stimulatory capacity. PDCs acquired TRAIL in an interferon (IFN)-[alpha]/[beta]-dependent fashion and, notably, low-level TRAIL-expression on pDCs could be induced by IFN-[alpha] stimulation alone. At a functional level both TLR7/8- (imiquimod, IMQ) and TLR9-stimulated (CpG2216) pDCs lysed Jurkat T cells in a TRAIL- and cell contact-dependent fashion. More importantly, IFN-[alpha]-activated pDCs acquired similar cytotoxic properties, independent of TLR stimulation and maturation. Both IMQ- and IFN-[alpha]-activated pDCs could also lyse certain melanoma cell lines in a TRAIL-dependent fashion. Interestingly, suboptimal doses of IMQ and IFN-[alpha] exhibited synergistic action leading to optimal TRAIL expression and melanoma cell lysis by pDCs. Our data imply that tumor immunity in patients receiving adjuvant IMQ and/or IFN-[alpha] may involve the active participation of cytotoxic pDCs.submitted by Madeleine L. KalbAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheWien, Med. Univ., Diss., 2013OeBB(VLID)171567

Missense Variants in the Histone Acetyltransferase Complex Component Gene TRRAP Cause Autism and Syndromic Intellectual Disability.

Acetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants

Missense Variants in the Histone Acetyltransferase Complex Component Gene TRRAP Cause Autism and Syndromic Intellectual Disability

International audienceAcetylation of the lysine residues in histones and other DNA-binding proteins plays a major role in regulation of eukaryotic gene expression. This process is controlled by histone acetyltransferases (HATs/KATs) found in multiprotein complexes that are recruited to chromatin by the scaffolding subunit transformation/transcription domain-associated protein (TRRAP). TRRAP is evolutionarily conserved and is among the top five genes intolerant to missense variation. Through an international collaboration, 17 distinct de novo or apparently de novo variants were identified in TRRAP in 24 individuals. A strong genotype-phenotype correlation was observed with two distinct clinical spectra. The first is a complex, multi-systemic syndrome associated with various malformations of the brain, heart, kidneys, and genitourinary system and characterized by a wide range of intellectual functioning; a number of affected individuals have intellectual disability (ID) and markedly impaired basic life functions. Individuals with this phenotype had missense variants clustering around the c.3127G>A p.(Ala1043Thr) variant identified in five individuals. The second spectrum manifested with autism spectrum disorder (ASD) and/or ID and epilepsy. Facial dysmorphism was seen in both groups and included upslanted palpebral fissures, epicanthus, telecanthus, a wide nasal bridge and ridge, a broad and smooth philtrum, and a thin upper lip. RNA sequencing analysis of skin fibroblasts derived from affected individuals skin fibroblasts showed significant changes in the expression of several genes implicated in neuronal function and ion transport. Thus, we describe here the clinical spectrum associated with TRRAP pathogenic missense variants, and we suggest a genotype-phenotype correlation useful for clinical evaluation of the pathogenicity of the variants