Together, our results reveal a novel regulatory mechanism of IL-22 expression by STAT1 through directly antagonizing STAT3, and the importance of the balance between STAT3 and STAT1 in IL-22 regulation and psoriasis pathogenesis.
Thus, CARMA2 serves as a key mediator of IL-17A signaling and its constitutive activation in keratinocytes leads to the onset of psoriasis, which indicates an important role of NF-κB activation in keratinocytes in psoriatic initiation.
Herein, we reported that K17 could be modified through ubiquitination that controlled its stability and led to the phosphorylation and nuclear translocation of its interactor signal transducers and activators of transcription 3 (STAT3), which is a key regulator of cell proliferation in psoriasis.
In conclusion, our findings identify a new mechanism through which the ability of CARMA2 to activate NF-κB is regulated, which could have significant implications for our understanding of why mutations of this protein trigger human psoriasis.
Several mouse models of psoriasis including drug-induced models (topical application of imiquimod to the skin) and genetically engineered mice (constitutive activation of epidermal STAT3, epidermal deletion of JunB/c-Jun, and epidermal overexpression of Tie2) have been used to study the pathophysiology of the disease; however such models cannot fully recapitulate all molecular and cellular pathways occurring in human psoriasis.
We also found that IL-22 increases CD147 transcription in vitro and in vivo and that Stat3 binds directly to the CD147 promoter between positions -854 and -440, suggesting that CD147 expression is up-regulated in patients with psoriasis through Stat3 activation.
rs744166GG in STAT3 and rs7574865TT in STAT4 had higher frequencies in the case than the control group, suggesting these 2 genotypes increase the susceptibility to psoriasis (p < 0.05).
This suggests that the difference in molecular charge and the resulting change in molecular interaction around the N-terminal end of the coiled-coil region of CARD14 molecule do not determine the phenotypic differences between psoriasis and PRP.
Collectively, our findings demonstrate a novel role for MALT1 in CARD14-induced signaling and indicate MALT1 as a valuable therapeutic target in psoriasis.
In summary, this paper describes a family with CARD14-related psoriasis and discusses the possible influence of the specific haplotypes on intra-familial variation in the clinical phenotype of the disease.
In contrast with wild-type CARD14, CARD14(E138A) and CARD14(G117S) psoriasis mutants interacted constitutively with BCL10 and MALT1, and triggered BCL10- and MALT1-dependent activation of NF-κB in keratinocytes.
Genome-wide association studies have found the single nucleotide polymorphism (SNP) c.C2458T, at the caspase recruitment domain family member 14 (CARD14) gene, to be associated with psoriasis.
CARD14 coding exons were resequenced in patients with psoriasis and controls from Tunisia and Europe, including 16 European cases with generalized pustular psoriasis (GPP).
These data indicate that the analysis of CARD14 mutations could help stratify pustular psoriasis cohorts but would be mostly uninformative in the context of psoriasis and sporadic PRP.
We identified the missense variant rs2303138 (p.Ala763Thr) within the LNPEP gene associated with psoriasis (Pcombined=1.83 × 10(-13), odds ratio=1.16) and validated four previously reported genes: IL28RA, NFKBIA, TRAF3IP2, and CARD14 (9.74 × 10(-11)P9.37 × 10(-5)), which confirmed the involvement of the nuclear factor-κB signaling pathway in psoriasis pathogenesis.
We further show that overexpression of hsa-miR-4516 downregulates STAT3, p-STAT3, CDK6, and UBE2N proteins that are consistently upregulated in psoriasis and induces apoptosis in HaCaT cells.