Valosin-containing Protein in Psoriasis: A Clinical and Immunohistochemical Study

Keratinocyte FABP5-VCP complex mediates recruitment of neutrophils in psoriasis

One of the hallmarks of intractable psoriasis is neutrophil infiltration in skin lesions. However, detailed molecular mechanisms of neutrophil chemotaxis and activation remain unclear. Here, we demonstrate a significant upregulation of epidermal fatty acid binding protein (E-FABP, FABP5) in the skin of human psoriasis and psoriatic mouse models. Genetic deletion of FABP5 in mice by global knockout and keratinocyte conditional (Krt6a-Cre) knockout, but not myeloid cell conditional (LysM-Cre) knockout, attenuates psoriatic symptoms. Immunophenotypic analysis shows that FABP5 deficiency specifically reduces skin recruitment of Ly6G+ neutrophils. Mechanistically, activated keratinocytes produce chemokines and cytokines that trigger neutrophil chemotaxis and activation in an FABP5-dependent manner. Proteomic analysis further identifies that FABP5 interacts with valosin-containing protein (VCP), a key player in NF-κB signaling activation. Silencing of FABP5, VCP, or both inhibits NF-κB/neutrophil chemotaxis signaling. Collectively, these data demonstrate dysregulated FABP5 as a molecular mechanism promoting NF-κB signaling and neutrophil infiltration in psoriasis pathogenesis.

Valosin containing protein (VCP): initiator, modifier, and potential drug target for neurodegenerative diseases

The AAA+ ATPase valosin containing protein (VCP) is essential for cell and organ homeostasis, especially in cells of the nervous system. As part of a large network, VCP collaborates with many cofactors to ensure proteostasis under normal, stress, and disease conditions. A large number of mutations have revealed the importance of VCP for human health. In particular, VCP facilitates the dismantling of protein aggregates and the removal of dysfunctional organelles. These are critical events to prevent malfunction of the brain and other parts of the nervous system. In line with this idea, VCP mutants are linked to the onset and progression of neurodegeneration and other diseases. The intricate molecular mechanisms that connect VCP mutations to distinct brain pathologies continue to be uncovered. Emerging evidence supports the model that VCP controls cellular functions on multiple levels and in a cell type specific fashion. Accordingly, VCP mutants derail cellular homeostasis through several mechanisms that can instigate disease. Our review focuses on the association between VCP malfunction and neurodegeneration. We discuss the latest insights in the field, emphasize open questions, and speculate on the potential of VCP as a drug target for some of the most devastating forms of neurodegeneration.

Chemokine Profile in Psoriasis Patients in Correlation with Disease Severity and Pruritus

Psoriasis (PsO) is a chronic, immune-mediated, inflammatory skin disease associated in most cases with pruritus. Chemokines seem to play a significant role in PsO pathogenesis. The aim of the study was to analyse serum concentrations of CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CCL5/RANTES, CCL17/TARC, CCL18/PARC, CCL22/MDC and CXCL8/IL-8, and their correlation with PsO severity and pruritus intensity. The study included 60 PsO patients and 40 healthy volunteers. Serum concentrations of six (CCL2/MCP-1, CCL3/MIP-1α, CCL5/RANTES, CCL17/TARC, CCL18/PARC and CCL22/MDC) out of eight analysed chemokines were significantly elevated in PsO patients; however, they did not correlate with disease severity. The serum level of CCL5/RANTES was significantly higher in patients with the psoriasis area and severity index (PASI) ≥ 15 (p = 0.01). The serum concentration of CCL17/TARC correlated positively with pruritus assessed using the visual analogue scale (VAS) (R = 0.47; p = 0.05). The study indicated CCL17/TARC as a potential biomarker of pruritus intensity in PsO patients. Chemokines appear to be involved in the development of PsO systemic inflammation. Further detailed studies on the interactions between chemokines, proinflammatory cytokines and immune system cells in PsO are required to search for new targeted therapies.