One individual with SLE who was positive for antiphospholipid antibodies and treated with 4 mg baricitinib developed a deep vein thrombosis (accounting for 1% of patients treated with 4 mg baricitinib). update of important findings about kidney diseases (including diabetic nephropathy, lupus PS-1145 nephritis, and vasculitis, i.e., vasculitis with antineutrophilic cytoplasmic antibodies). New disease targets, potential pathological pathways, and promising therapeutic approaches from basic science to clinical practice are presented, and the blocking of JAK/STAT and TIM-1/TIM-4 signaling pathways as potential novel therapeutic agents in lupus nephritis is discussed. receptors (IL-6Rs) on activated B cells induces dimerization with the transmembrane protein gp130 and the activation of the receptor-associated Janus kinase (JAK) tyrosine kinases JAK1 and JAK2. This is the most important role of IL-6, as it is involved in multiple autoimmune diseases and contributes directly to the survival of plasma cells in the bone marrow niche (13). Effector T cells also recognize autoantigens that are present in the kidneys as implanted or endogenous antigens (14C18), and fewer CD4+ and CD8+ cells are recruited to the glomerulus and stroma. The members of the T-cell immunoglobulin mucin-domain (TIM) family encode a protein that has an IgV-like domain and a mucin domain (19), and the three human TIM genes most similar to those in mice are TIM-1, TIM-3, and TIM-4. The roles of TIM proteins in T-cell differentiation, effector function, autoimmunity, and allergy are becoming clear (20), and it was demonstrated that TIM-1 is expressed on activated T cells (21). Another study suggested that TIM-1 on T cells acts as a costimulatory molecule to enhance cell proliferation and cytokine production and to mediate the loss of tolerance (22). Chemokines and adhesion molecules are reduced by TIM-1 antibodies (18). In intracellular adhesion molecule-1 (ICAM-1) knockout mice treated with TIM-1 antibody, the PS-1145 renal and spleen mRNA expressions of the Th1 chemokines CXCL9 and CXCL10 were reduced and ICAM-1 mediated the recruitment of leukocytes in glomerulonephritis (23). A promising next research task would be to target inflammatory cytokines a blockade of the JAK-signaling transducer and transcriptional activator (STAT) and TIM-1 signaling pathways, in order to better target the development and survival of autoreactive pathogenic plasma cells during the early stages of SLE. In this review, new therapeutic targets for lupus nephritis, potential pathologies and promising therapeutic approaches to the JAK-STAT and TIM-1-TIM-4 signaling pathways from basic science to clinical practice are presented. Mechanisms Downstream of the JAK-STAT Pathway PS-1145 Several signaling pathways are known to be involved in the progression of renal disease in both humans and animal models, and the progression is usually due to a sustained cytokine and JAK-STAT activation of these pathways (24). The JAK-STAT pathway is downstream of the type I and II cytokine receptors. As part of a major signaling cascade, JAK is an effective therapeutic target for a variety of cytokine-driven autoimmune and inflammatory diseases (25, 26). A cytosolic tyrosine kinase, JAK has been demonstrated to be an effective therapeutic target for a wide range of cell-surface receptors, and members of the cytokine receptor common gamma (cg) chain family in particular are involved in signaling (27). There are four mammalian JAKs: JAK1, JAK2, JAK3, and tyrosine kinase 2 (Tyk2). The activation of JAKs occurs ligand-receptor interactions and results in the phosphorylation of the cytokine receptor; the signaling occurs the generation of docking sites for signaling proteins known as COL4A5 STATs (19). JAKs catalyze the phosphorylation of STATs and promote STAT dimerization and nuclear transport, thereby regulating gene expression and transcription (28, 29). The JAK proteins are structurally related but different in their activation and their downstream effects; their high specificity is thus expected (Figure 1). Open in a separate window Figure 1 JAK inhibition and immune regulation by the JAK pathway. The PS-1145 inhibition of JAK3 would affect the signaling mediated by only the common gamma chain-associated cytokine receptors (IL-2R, IL-4R, IL-9R, and IL-21R) and regulate T-cell, NK cell, and B-cell function. PS-1145 JAK2 or Tyk2 inhibition would influence multiple cytokine receptor signaling pathways. CNTFR, ciliary neurotrophic factor receptor; EPO, erythropoietin; GH, growth hormone; GM-CSF, granulocyte macrophage colony-stimulating factor; IFN, interferon; IL, interleukin; NK, natural killer; PRL, prolactin receptor; TPO, thrombopoietin. JAK1 is a receptor (IFN-/, IFN-, and IL-10) and c, which is activated by ligands that bind to receptors (IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21). JAK2 is activated primarily by the.