Psoriasis is a common and chronic inflammatory skin disease that is complicated by gene–environment interactions. Although genomic, transcriptomic, and proteomic analyses have been performed to investigate the pathogenesis of psoriasis, the role of metabolites in psoriasis, particularly of lipids, remains unclear. Lipids not only comprise the bulk of the cellular membrane bilayers but also regulate a variety of biological processes such as cell proliferation, apoptosis, immunity, angiogenesis, and inflammation. In this study, an untargeted lipidomics approach was used to study the lipid profiles in psoriasis and to identify lipid metabolite signatures for psoriasis through ultra-performance liquid chromatography-tandem quadrupole mass spectrometry. Plasma samples from 90 participants (45 healthy and 45 psoriasis patients) were collected and analyzed. Statistical analysis was applied to find different metabolites between the disease and healthy groups. In addition, enzyme-linked immunosorbent assay was performed to validate differentially expressed lipids in psoriatic patient plasma. Finally, we identified differential expression of several lipids including lysophosphatidic acid (LPA), lysophosphatidylcholine (LysoPC), phosphatidylinositol (PI), phosphatidylcholine (PC), and phosphatidic acid (PA); among these metabolites, LPA, LysoPC, and PA were significantly increased, while PC and PI were down-regulated in psoriasis patients. We found that elements of glycerophospholipid metabolism such as LPA, LysoPC, PA, PI, and PC were significantly altered in the plasma of psoriatic patients; this study characterizes the circulating lipids in psoriatic patients and provides novel insight into the role of lipids in psoriasis.

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In recent years, a number of TKIs (tyrosine kinase inhibitors) targeting epidermal growth factor receptor (EGFR) family have been synthesized and some have been approved for clinical treatment of cancer by the FDA. We recently reported a new pharmacological action of the 4-anilinoquinazoline derived EGFR TKIs, such as lapatinib (Tykerb®) and erlotinib (Tarceva®), which significantly affect the drug resistance patterns in cells expressing the multidrug resistance (MDR) phenotype. Previously, we showed that lapatinib and erlotinib could inhibit the drug efflux function of P-glycoprotein (P-gp, ABCB1) and ABCG2 transporters. In this study, we determined if these TKIs have the potential to reverse MDR due to the presence of the multidrug resistance protein 7 (MRP7, ABCC10). Our results showed that lapatinib and erlotinib dose-dependently enhanced the sensitivity of MRP7-transfected HEK293 cells to several established MRP7 substrates, specifically docetaxel, paclitaxel, vinblastine and vinorelbine, whereas there was no or a lesser effect on the control vector transfected HEK293 cells. [3H]-paclitaxel accumulation and efflux studies demonstrated that lapatinib and erlotinib increased the intracellular accumulation of [3H]-paclitaxel and inhibited the efflux of [3H]-paclitaxel from MRP7 transfected cells but not in the control cell line. Lapatinib is a more potent inhibitor of MRP7 than erlotinib. In addition, the Western blot analysis revealed that both lapatinib and erlotinib did not significantly affect MRP7 expression. We conclude that the EGFR TKIs, lapatinib and erlotinib reverse MRP7-mediated MDR through inhibition of the drug efflux function, suggesting that an EGFR TKI based combinational therapy may be applicable for chemotherapeutic practice clinically.

Psoriasis affects the health of myriad populations around the world. The pathogenesis is multifactorial, and the exact driving factor remains unclear. This condition arises from the interaction between hyperproliferative keratinocytes and infiltrating immune cells, with poor prognosis and high recurrence. Better clinical treatments remain to be explored. There is much evidence that alterations in the skin and intestinal microbiome play an important role in the pathogenesis of psoriasis, and restoration of the microbiome is a promising preventive and therapeutic strategy for psoriasis. Herein, we have reviewed recent studies on the psoriasis-related microbiome in an attempt to confidently identify the “core” microbiome of psoriasis patients, understand the role of microbiome in the pathogenesis of psoriasis, and explore new therapeutic strategies for psoriasis through microbial intervention.