RESUMEN
Cutaneous immune-related adverse events (irAEs) of immunotherapies, such as anti-programmed cell death protein-1 (PD-1), suggest that immune checkpoint factors may contribute to the pathobiology of lichenoid interface dermatitis in immunotherapy-naïve patients. Our study aimed to describe innate and adaptive immune markers via immunohistochemical (IHC) staining of lichenoid interface dermatoses. We studied the staining patterns of PD-L1, STING, IL-36 gamma, CD8, PD-1, and LAG-3 in five interface dermatoses: oral lichen planus (LP) (n = 10), cutaneous LP (n = 10), chronic cutaneous lupus erythematosus (CLE) (n = 11), erythema multiforme (EM) (n = 11), and toxic epidermal necrolysis (TEN) (n = 13), by immunohistochemistry (IHC) analysis. Expression was evaluated semi-quantitively according to the percentage of keratinocytes and dermal lymphocytes stained compared to keratinocytes and resident pericapillary lymphocytes in normal human skin. All interface dermatoses evaluated showed increased expression of PD-L1 on keratinocytes and LAG-3 in lymphocytes. STING was increased on the keratinocytes of most specimens. Expression of IL-36 gamma, in basal layer keratinocytes was more extensive in oral LP and cutaneous LP and varied in CLE, EM, and TEN. Lymphocytic infiltration expressing PD-1 was elevated in oral LP, cutaneous LP, and CLE. Current thinking is that interface dermatitis is the result of a cell-mediated immune reaction involving cytotoxic CD8+ T-cell-mediated apoptosis of keratinocytes. The findings of this study suggest that in addition to cell-mediated immunity, innate immune factors may contribute to pathobiology.
RESUMEN
The SMCR8-WDR41-C9ORF72 complex is a regulator of autophagy and lysosomal function. Autoimmunity and inflammatory disease have been ascribed to loss-of-function mutations of Smcr8 or C9orf72 in mice. In humans, autoimmunity has been reported to precede amyotrophic lateral sclerosis caused by mutations of C9ORF72 However, the cellular and molecular mechanisms underlying autoimmunity and inflammation caused by C9ORF72 or SMCR8 deficiencies remain unknown. Here, we show that splenomegaly, lymphadenopathy, and activated circulating T cells observed in Smcr8-/- mice were rescued by triple knockout of the endosomal Toll-like receptors (TLRs) TLR3, TLR7, and TLR9. Myeloid cells from Smcr8-/- mice produced excessive inflammatory cytokines in response to endocytosed TLR3, TLR7, or TLR9 ligands administered in the growth medium and in response to TLR2 or TLR4 ligands internalized by phagocytosis. These defects likely stem from prolonged TLR signaling caused by accumulation of LysoTracker-positive vesicles and by delayed phagosome maturation, both of which were observed in Smcr8-/- macrophages. Smcr8-/- mice also showed elevated susceptibility to dextran sodium sulfate-induced colitis, which was not associated with increased TLR3, TLR7, or TLR9 signaling. Deficiency of WDR41 phenocopied loss of SMCR8. Our findings provide evidence that excessive endosomal TLR signaling resulting from prolonged ligand-receptor contact causes inflammatory disease in SMCR8-deficient mice.
Asunto(s)
Proteína C9orf72/metabolismo , Proteínas Portadoras/metabolismo , Inflamación/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Receptores Toll-Like/metabolismo , Animales , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/metabolismo , Proteínas Relacionadas con la Autofagia , Proteína C9orf72/genética , Proteínas Portadoras/genética , Colitis/inducido químicamente , Sulfato de Dextran , Regulación de la Expresión Génica , Hematopoyesis/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Ratones , Ratones Noqueados , Mutación , Transducción de Señal/inmunología , Receptores Toll-Like/genéticaRESUMEN
Myosin ID (MYO1D) is a member of the class I myosin family. We screened 48,649 third generation (G3) germline mutant mice derived from N-ethyl-N-nitrosourea-mutagenized grandsires for intestinal homeostasis abnormalities after oral administration of dextran sodium sulfate (DSS). We found and validated mutations in Myo1d as a cause of increased susceptibility to DSS-induced colitis. MYO1D is produced in the intestinal epithelium, and the colitis phenotype is dependent on the nonhematopoietic compartment of the mouse. Moreover, MYO1D appears to couple cytoskeletal elements to lipid in an ATP-dependent manner. These findings demonstrate that MYO1D is needed to maintain epithelial integrity and protect against DSS-induced colitis.