mTOR signaling cascade in psoriatic disease: Double kinase mtor inhibitor a novel therapeutic target

In this short communication we are providing insight about the regulatory role of the phosphatidylinositol 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) kinase system in psoriatic disease. This is an upcoming active research field in respect to elucidating the inflammatory and proliferative cascades of psoriatic disease. To provide a new dimension to the understandings of the molecular principles of the pathogenesis of autoimmune diseases, we hypothesized that (i) dysregulation of cytokines and growth factors in autoimmune diseases activate the mTOR signaling system and (ii) the activated mTOR kinase system is a key regulator of the inflammatory/proliferative cascades of the disease process. In support of this hypothesis we have earlier reported that growth factors (nerve growth factor (NGF) and platelet-derived growth factor (PDGF)) and relevant cytokines (interleukin (IL)-17, IL-22) known to be critical for psoriasis, psoriatic arthritis, and rheumatoid arthritis activate the mTOR signaling system. Here, we are providing our latest observations that the mTOR signaling proteins are upregulated in psoriatic skin and further we observed that proliferation of keratinocytes (KC) and synovial cells (synovial fibroblasts (FLS)) of psoriatic arthritis are dependent on the PI3K-AKT-mTOR kinase system. To our knowledge, we are the first to explore whether a double kinase inhibitor of mTOR signal proteins has a therapeutic potential for psoriatic disease. Here we will be sharing our views, our research work in this field and as well we will provide evidences how a double kinase inhibitor of mTOR signal proteins can be an effective therapeutic agent for psoriatic disease

SCID MOUSE MODEL OF PSORIASIS: A UNIQUE TOOL FOR DRUG DEVELOPMENT OF AUTOREACTIVE T-CELL AND TH-17 CELL-MEDIATED AUTOIMMUNE DISEASES

In both skin and synovial tissues of psoriatic arthritis (PsA) patients, there are prominent lymphocytic infiltrates localized to the dermal papillae in the skin and the sublining layer stroma in the joint. T-cells, with a predominance of CD4+ lymphocytes, are the most significant lymphocytes in the tissues; in contrast, this ratio is reversed in the epidermis, synovial fluid compartment, and at the enthesis, where CD8+ T-cells are more common. This differential tropism of CD8+ T-cell suggests that the CD8+ T-cells may be driving the immune response in the joint and skin. This is supported by an association with MHC class I. The cytokine network in the psoriatic skin and synovium is dominated by monocyte and T-cell-derived cytokines: IL-1β, IL-2, IL-10, IFN-γ, and TNF-α. In PsA synovium, higher levels of IFN-γ, IL-2, and IL-10 have been detected than in psoriatic skin. An analysis of T-cell receptor beta-chain variable (TCRβV) gene repertoires revealed common expansions in both skin and synovial inflammatory sites, suggesting an important role for cognate T-cell responses in the pathogenesis of PsA and that the inciting antigen may be identical or homologous between the afflicted skin and synovium. Traditionally, T-cells have been classified as T helper 1 (Th1) or Th2 cells by production of defining cytokines, IFN-γ and IL-4, respectively. Recently, a new type of T-cell, Th17, has been linked to autoimmune inflammation. T-helper 17 (Th17) cells are a unique effector CD4+ T-cell subset characterized by the production of interleukin (IL)-17. Murine diseases that were previously considered to be pure Th1-mediated responses have been shown to contain mixed populations of Th1 and Th17 cells. Also, in humans, a critical immunoregulatory role of Th-17 cells in infectious and autoimmune diseases has been identified. It has been postulated that IL-17 may be important in psoriasis. Our initial observations demonstrate that IL-17 and its receptor system are important for PsA also. In in vivo and in vitro studies we have demonstrated that IL-17/IL-17R are enriched in skin, synovial tissue, and synovial fluid of psoriatic arthritis patients and Th17 cells are functionally significant in the pathogenesis of psoriasis and psoriatic arthritis. Here we will share our experience of the SCID mouse model of psoriasis in respect to its use in investigating psoriatic diseases and development of immune-based drugs for psoriasis, psoriatic arthritis, and other autoimmune diseases