2016 Research Trainee Symposium: Project Summaries and Posters
Yvonne Baumer, Ph.D.
Teal Furnholm, Ph.D.
Title: “Elucidating microbiome involvement in psoriasis through combined RNA-seq and metabolomics."
Changes in the skin microbiome and triggering of psoriasis skin lesions with streptococcal infections indicate microbes play an important role in psoriasis. We hypothesize that microbial dysbiosis leads to the altered gene and metabolite expression patterns that drive psoriatic immune dysregulation. A universal RNA-seq database was created with the complete collections of NIH, GENCODE and JGI databases containing gene clusters from all kingdoms of life. Using this database, we simultaneously examined the host and microbial community metatranscriptome of swabs from psoriasis patients and healthy controls. Streptococcus was the most abundant taxa based on the proportion of differentially expressed genes, particularly those involved in cell surface modification and immune evasion. Bacterial, fungal, and human metabolic pathways were overlaid and examined for linked gene expression patterns to pinpoint psoriasis-related path alterations. Lipid metabolism, including phospholipase D, terpenoid and arachidonic acid pathways had significant bacterial alterations in psoriasis samples, suggesting microbial influence on pro-inflammatory lipid production. Swabs from the psoriasis patients are being analyzed for lipid and polar metabolites. Preliminary results show changes in host sphingosine and ceramides, as well as increased bacterial isoprenoids that point to bacterial secondary metabolite involvement in psoriasis.
Oliver Harrison, D. Phil
Title: “The role of commensal-specific immunity in the pathogenesis of experimental psoriasis”
The skin is a key barrier between host and environment, and is exposed to numerous environmental insults. Furthermore, the skin also hosts a diverse commensal microbiota, which is a critical modulator of skin immunity during homeostasis and infection. However, recent findings demonstrate that psoriatic skin lesions harbour an altered composition of commensal microbes compared to healthy skin, termed dysbiosis. How dysbiosis, disease progression and commensal-specific immunity influence psoriatic inflammation remains unknown. Using a murine model of psoriatic-like skin inflammation, we noted a role for disease modulation by skin commensal microbes. Notably, Germ-free mice, devoid of commensals, develop significantly attenuated skin inflammation compared to WT, commensal-colonized, controls. Conversely, topical colonization of mice with defined skin isolates increased tissue pathology during experimental skin inflammation. To address the role of commensal-specific T cells in experimental psoriasis we have begun generating commensal-specific TCR-transgenic mice. These TCR-transgenic mice will allow direct tracking of T cell responses to commensal microbes preceding, and during, experimental skin inflammation. Our aim is to understand the mechanisms controlling how the cutaneous immune system responds to commensal organisms in health, and disease.
Melissa LaJevic, Ph.D.
Title: “Role of Chemerin in the Pathomechanism of Psoriasis”
Chemerin is a proteolytically activatable chemoattractant for leukocytes expressing chemokine like receptor 1 (CMKLR1). While chemerin is elevated in the dermis and co-localizes with CMKLR1+ leukocytes in human psoriatic skin, the role of chemerin in the pathomechanism of psoriasis remains unknown. We investigated the role of chemerin in the imiquimod (IMQ)-induced mouse model of psoriasis, which mimics key features of psoriatic plaque formation in humans. Within 24h of IMQ challenge, skin chemerin RNA and protein levels were significantly upregulated. Compared with WT mice, chemerin-deficient mice were protected against clinical signs and histological features of IMQ-induced psoriasis. IMQ-induced skin recruitment of CMKLR1+ NK cells and macrophages was also significantly diminished in chemerin KO mice vs. WT. Interestingly, certain synthetic chemerin-derived peptides were reported to have biological activity in vivo. While chemerin C9 peptide recapitulates some of the endogenous activity of the holo-protein, chemerin C15 peptide was recently discovered to have anti-inflammatory properties. In the IMQ-model, topical C15 treatment reduced clinical signs of disease compared to controls. We suggest that chemerin normally serves to drive the pathogenesis of psoriasis by recruiting pro-inflammatory CMKLR1+ leukocytes, and that skin treatment with anti-inflammatory chemerin C15 peptide ameliorates disease.
Katherine Lewandowski, Ph.D.
Systemically-administered TNF inhibitors are highly effective for moderate-to-severe plaque psoriasis but are high-cost and associated with risks. Targeted therapy for topical delivery is needed. Novel spherical nucleic acids (SNAs) for topical gene regulation penetrate the epidermis when delivered in a moisturizer, leading to targeted gene knockdown without toxicity or immune activation. We hypothesized that SNAs targeting human TNF could reverse the psoriatic phenotype. We engineered TNF nanoconjugates with antisense DNA arrayed around a biodegradable liposomal nanoparticle (L-SNAs). L-SNAs suppressed TNF mRNA and protein expression in human monolayer keratinocytes by 89% and 70%, respectively, while decreasing S100A7 mRNA by 52% and β-DEF2A (β-defensin 2) by 56% (p<0.001). Using a cytokine-induced 3-D model of human psoriasis, we treated rafts with 50 nM TNF L-SNAs or scrambled L-SNAs at 9d after lifting and rafts were harvested at 12d. L-SNAs targeting TNF decreased TNF mRNA by 52%, improved the abnormal differentiation, and reversed the psoriatic transcriptomic profile. Finally, topically applied TNF L-SNAs prevented the psoriatic-like phenotype in an imiquimod-induced mouse model. Mouse skin was analyzed histologically and transcriptomically, and showed normalization in expression of TNF and psoriatic markers. L-SNAs targeting TNF are a promising new topically delivered gene therapy for treating plaque psoriasis.
Pablo Michel, M.D.
We will present the transcriptional signature in blood of 126 moderate to severe psoriasis patients compared to 39 age, gender and ethnicity matched healthy controls. All the psoriasis patients had a coronary artery calcium score taken as an evidence of the degree of calcification in their coronary arteries. The genomic studies were performed through microarray analysis and we are aiming to correlate the presence of coronary artery disease with a distinctive transcriptional signature in this cohort with the ultimate goal of starting the identification of a biomarker in the blood of psoriasis patients. Modular analysis and Ingenuity pathway analysis, among other tools, will be used to compare the psoriasis transcriptome with other inflammatory diseases and its connection with key pathophysiological mechanisms described for the disease. Each differentially expressed gene will be presented according to its relative contribution to cardiovascular disease.
Megan Noe, M.D., M.P.H.
Hepatitis C infection (HCV) is a major cause of global morbidity and mortality. There is conflicting evidence regarding an association between HCV and psoriasis. The purpose of this study is to determine the prevalence of HCV in psoriasis patients in the United Kingdom, and to determine the incidence of hepatic decompensation in HCV+ psoriasis patients compared to controls. Cross-sectional & cohort studies were conducted in The Health Improvement Network (THIN), a primary care database. A sub-analysis was performed in the Incident Heath Outcomes and Psoriasis Events (iHOPE) cohort, a group of patients with objective information regarding psoriasis severity. In fully adjusted models, a statistically significant increase in prevalence was seen in adults with psoriasis (OR: 1.24, 95% CI 1.10 - 1.40). A “dose-response” of HCV prevalence with increasing psoriasis severity was not observed. HCV+ patients with psoriasis had a non-statistically significant increased incidence of hepatic decompensation compared to HCV+ individuals without psoriasis (aHR: 1.58, 95% CI: 0.90- 2.77). The risk was highest, and statistically significant, in those with moderate to severe psoriasis (aHR: 21.51, 95% CI: 7.58-61.03). These results demonstrate a higher prevalence of HCV in adults with psoriasis and a higher rate of hepatic decompensation in HCV+ individuals with moderate - severe psoriasis. Further research is necessary to better understand the biological mechanisms underlying this association.
Mrinal Sarkar, Ph.D.
Psoriasis is a common cytokine driven inflammatory skin disease characterized by hyper-proliferation and altered epidermal differentiation. Tyk2, a psoriasis susceptibility gene, mediates signaling downstream of many key psoriasis cytokines, including type I interferons (IFNs). In this study we knocked-out (KO) TYK2 in keratinocytes by CRISPR/Cas9 technology to investigate the mechanism of type I IFN responses in psoriasis. As expected TYK2 KO completely suppressed type I IFN responses (P< 0.001), including IFNK mRNA (n=3, FC=0.24, P<3.00E-36). Surprisingly, TYK2 KO led to suppression of IFN response genes in unstimulated KCs (P=6.2E-06), including IFNK mRNA (n=3, FC=0.38, P<2.00E-15), suggesting a baseline, autocrine type I IFN pathway in keratinocytes mediated by IFN-κ. A finding we confirmed by IFNK KO in KCs. We furthermore demonstrated that TYK2 KO completely blocks type I IFN STAT1 phosphorylation in keratinocytes, but does not affect phosphorylation of STAT2 or STAT3. Our observations suggest that type I IFNs propagate their signaling through Tyk2 and p-STAT1 pathway in psoriasis. Further exploration of this process could lead to novel therapeutic approaches in psoriasis.
Antia Veal, Ph.D.
Title: "Inhibition of Psoriasis through Suppressor of Cytokine Signaling-1 Regulation"
Psoriasis is a chronic auto-inflammatory disorder with a prevalence of 0.9-8.5% worldwide. As such, identifying novel therapeutic targets to treat psoriasis patients that are refractory or intolerant to conventional strategies will have an effect on quality of life. Recently, its shown clear that the proinflammatory cytokines, IL17 and IL23, have a critical role in psoriasis progression. Importantly, SOCS1, is induced by mediators of pro-inflammatory signaling and limit the duration of the inflammatory signaling cascade that mediated its induction. The inability to properly up-regulate SOCS1 has been demonstrated in autoimmune disease patients, indicating that regulation of SOCS1 signaling is a key immunomodulatory target for autoimmunity like psoriasis. Significantly, female SOCS1+/-IFNg-/- spontaneously develop an IL17 dependent epidermal hyperplasia, and may serve as a novel model of psoriasis. In addition, we’ve recently shown that the topical administration of a cell-penetrating peptide that partially mimics SOCS1 function (SOCS1-KIR) was completely effective in mitigating auto-inflammatory eye disease in a rodent system. We hypothesize that SOCS1 is a key regulator of psoriasis onset/progression and SOCS1+/-IFNg-/- mice can serve as a novel rodent model of spontaneous psoriasis. We propose to test topical administration of SOCS1-KIR to effectively inhibit psoriasis-like pathology in SOCS1+/-IFNg-/- mice and in the established Imiquimod rodent model of induced psoriasis.