Proteomics of Skin Proteins in Psoriasis: From Discovery and Verification in a Mouse Model to Confirmation in Humans

Abstract

Herein, we demonstrate the efficacy of an unbiased proteomics screening approach for studying protein expression changes in the KC-Tie2 psoriasis mouse model, identifying multiple protein expression changes in the mouse and validating these changes in human psoriasis. KC-Tie2 mouse skin samples (n ‫؍‬ 3) were compared with littermate controls (n ‫؍‬ 3) using gel-based fractionation followed by label-free protein expression analysis. 5482 peptides mapping to 1281 proteins were identified and quantitated: 105 proteins exhibited fold-changes >2.0 including: stefin A1 (average fold change of 342.4 and an average p ‫؍‬ 0.0082; cystatin A, human ortholog); slc25a5 (average fold change of 46.2 and an average p ‫؍‬ 0.0318); serpinb3b (average fold change of 35.6 and an average p ‫؍‬ 0.0345; serpinB1, human ortholog); and kallikrein related peptidase 6 (average fold change of 4.7 and an average p ‫؍‬ 0.2474; KLK6). We independently confirmed mouse gene expression-based increases of selected genes including serpinb3b (17.4-fold, p < 0.0001), KLK6 (9-fold, p ‫؍‬ 0.002), stefin A1 (7.3-fold; p < 0.001), and slc25A5 (1.5-fold; p ‫؍‬ 0.05) using qRT-PCR on a second cohort of animals (n ‫؍‬ 8). Parallel LC/MS/MS analyses on these same samples verified protein-level increases of 1.3-fold (slc25a5; p < 0.05), 29,000-fold (stefinA1; p < 0.01), 322-fold (KLK6; p < 0.0001) between KC-Tie2 and control mice. To underscore the utility and translatability of our combined approach, we analyzed gene and protein expression levels in psoriasis patient skin and primary keratinocytes versus healthy controls. Increases in gene expression for slc25a5 (1.8-fold), cystatin A (3-fold), KLK6 (5.8-fold), and serpinB1 (76-fold; all p < 0.05) were observed between healthy controls and involved lesional psoriasis skin and primary psoriasis keratinocytes. Moreover, slc25a5, cystatin A, KLK6, and serpinB1 protein were all increased in lesional psoriasis skin compared with normal skin. These results highlight the usefulness of preclinical disease models using readily-available mouse skin and demonstrate the utility of proteomic approaches for identifying novel peptides/proteins that are differentially regulated in psoriasis that could serve as sources of autoantigens or provide novel therapeutic targets for the development of new anti-psoriatic treatments. One in three individuals in the United States is afflicted with a skin disease, with ϳ2-3% of the American population suffering from psoriasis (1-3) a chronic, immune-mediated inflammatory skin disease characterized by well-demarcated areas of "involved" red, raised, and scaly skin adjacent to areas of "uninvolved" normal appearing skin. The underlying cause of psoriasis remains unknown and the specific signals that trigger disease onset have yet to be identified; however, several lines of evidence suggest the involvement of antigenspecific T cells, although the antigens involved remain elusive (4). A combination of human and animal studies have led to the understanding that in patients with a genetica...

Endogenous Glucocorticoid Deficiency in Psoriasis Promotes Inflammation and Abnormal Differentiation

“…Psoriasis is marked by gross histologic alterations (Lowes et al , 2014) that are accompanied by pervasive transcriptomic (Jabbari et al , 2012; Li et al , 2014; Swindell et al , 2013) and proteomic (Lundberg et al , 2015; Swindell et al , 2015) changes in inflamed skin. However, global metabolic changes have not previously been addressed in psoriatic skin.…”

Isl1 Controls Patterning and Mineralization of Enamel in the Continuously Renewing Mouse Incisor

“…Using qPCR, we confirmed that six of these 10 genes were indeed significantly differentially expressed. Otx1 and Tekt2 play a role in inner ear development; Scg2 (also known as secretoneurin) interacts with STAT3, a known ISL1‐interaction partner; Ptprv is associated with bone and energy metabolism, as well as P53‐induced cell cycle exit; Pdzk1ip1 (or Pdzk1 ‐interacting protein 1) also interacts with Twist1, an important regulator of the Bmp signaling pathways; and Stfa1 was observed to be overexpressed in a mouse psoriasis model . Moreover, Otx1 , Ptprv , and Scg2 are all expressed in E14.5 incisor tooth germs (http://genepaint.org/Frameset.html).…”

“…Pdzk1ip1 (or Pdzk1-interacting protein 1) also interacts with Twist1, an important regulator of the Bmp signaling pathways (57) ; and Stfa1 was observed to be overexpressed in a mouse psoriasis model. (58) Moreover, Otx1, Ptprv, and Scg2 are all expressed in E14.5 incisor tooth germs (http://genepaint.org/ Frameset.html). The remaining four genes, Kif27a, Frem3, Shisa7, and Hmgn2, showed similar trends to the RNA-Seq results but did not reach statistical significance (Fig.…”

The effect of photodamage on the female Caucasian facial stratum corneum corneome using mass spectrometry‐based proteomics

“…These approaches have been highly successful in helping us to determine the general composition of the SC but each has their limitations. The use of mass spectrometry-based 'omic' approaches is on the increase for investigating skin biochemistry especially proteomics [13][14][15][16][17][18][19]. Recently, these methods have been used to determine differences in the corneome of dry skin on the leg of post-menopausal women and dandruff on the scalp [20][21][22].…”