Extracellular nucleophosmin is upregulated in psoriasis and correlates with determinants of cardiovascular diseases

Abstract

Abstract Introduction We previously showed that genotoxic stress induced an active extracellular release of nucleophosmin (NPM) in human cardiac mesenchymal progenitor cells, and that serum deprivation provokes NPM secretion from human endothelial cells, eliciting inflammation via nuclear factor kappa B (NF-kB) transcriptional activation. Purpose The aim of this study was to determine whether NPM was modulated in skin and plasma of psoriatic patients (Pso). Methods 29 Pso were compared to 29 control subjects (Ctrl) age- and sex-matched. All Pso had a severe psoriasis, defined as Psoriasis Area and Severity Index (PASI) >10 and one of the following: at least two systemic psoriasis treatments, psoriasis onset <40 years of age, disease duration >10 years. Exclusion criteria were: diabetes, cardiovascular events, psoriatic arthritis. Total RNA was extracted from plasma and miR-200c levels assayed by quantitative real-time PCR. NPM levels were assayed by ELISA. The clinical parameters were similar between the two groups except for Total Cholesterol (mg/dl) (Ctrl 193.3±6.2; Pso 213.2±6.9; P<0.05). Blood pressure measurement, wave reflection analysis and pulse wave velocity (PWV) were similar between groups, echocardiographic parameters were different for left ventricular (LV) mass index (g/m2) (Ctrl 84.2±5.2; Pso 102.5±4.7; P<0.05) and relative wall thickness (RWT) (Ctrl 0.4±0.0; Pso 0.48±0.0; P<0.01). Total RNA was extracted from biopsies of nonlesional (NLS) and lesional (LS) of 6 Pso and 6 healthy subject skin (HS) from which human fibroblasts (HFs) and primary Keratinocytes (KCs) were extracted. Results NPM was upregulated in LS (1.9+0.3 fold; p=0.05) vs NLS biopsies (2.9+0.1 fold; p<0.01) and was also increased at the transcriptional level in LS vs NLS (8.6+ 1.7fold; p<0.05). Both the innate stimuli, such as lipopolysaccharides and Poly I:C and adaptive stimuli, i.e. cytokine mix, were able to induce extracellular release of NPM in immortalized KCs and HFs. Interestingly, NPM interacts with Toll like receptor (TLR)4 and activates a NF-kB-dependent inflammatory pathway upregulating interleukin IL-6 and COX-2 gene expression. Circulating NPM was increased in the plasma of 29 Pso (1.1+0.1ng/ml; p<0.001) compared to 29 healthy controls (0.78+ 0.03ng/ml) and positively correlates with PASI (Rs=0.44; p=0.05) and with determinants of cardiovascular diseases (CVDs), i.e. PWV (Rs=0.5; p<0.008), PASis (Rs= 0.4; P<0.05) and LV mass (Rs=0.49; p<0.05). Further, NPM positively correlates with miR-200c circulating levels (Rs=0.29; p<0.05), that we previously showed to increase in Pso and to correlate with CVD progression. We found that circulating miR-200c physically associated with NPM, that most probably is responsible for its extracellular release and protection upon cytokine mix via a TLR4-mechanism. Conclusions NPM is increased in psoriasis both in skin and in plasma and could be a novel biologic target to counteract chronic inflammation associated with CVD risk. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Italian Ministry of Health and AFM Telethon 22522 grant to AM