技术资料

Lupus nephritis (LN) is a potentially dangerous end organ pathology that affects upwards of 60% of lupus patients. Bruton's tyrosine kinase (BTK) is important for B cell development,Fc receptor signaling,and macrophage polarization. In this study,we investigated the effects of a novel,highly selective and potent BTK inhibitor,BI-BTK-1,in an inducible model of LN in which mice receive nephrotoxic serum (NTS) containing anti-glomerular antibodies. Mice were treated once daily with vehicle alone or BI-BTK-1,either prophylactically or therapeutically. When compared with control treated mice,NTS-challenged mice treated prophylactically with BI-BTK-1 exhibited significantly attenuated kidney disease,which was dose dependent. BI-BTK-1 treatment resulted in decreased infiltrating IBA-1+ cells,as well as C3 deposition within the kidney. RT-PCR on whole kidney RNA and serum profiling indicated that BTK inhibition significantly decreased levels of LN-relevant inflammatory cytokines and chemokines. Renal RNA expression profiling by RNA-seq revealed that BI-BTK-1 dramatically modulated pathways related to inflammation and glomerular injury. Importantly,when administered therapeutically,BI-BTK-1 reversed established proteinuria and improved renal histopathology. Our results highlight the important role for BTK in the pathogenesis of immune complex-mediated nephritis,and BTK inhibition as a promising therapeutic target for LN. View Publication

In order to investigate the biologic processes underlying and resulting from the megakaryocytic hyperplasia that characterizes idiopathic myelofibrosis (IMF),peripheral blood CD34+ cells isolated from patients with IMF,polycythemia vera (PV),and G-CSF-mobilized healthy volunteers were cultured in the presence of stem cell factor and thrombopoietin. IMF CD34+ cells generated 24-fold greater numbers of megakaryocytes (MKs) than normal CD34+ cells. IMF MKs were also shown to have a delayed pattern of apoptosis and to overexpress the antiapoptotic protein bcl-xL. MK hyperplasia in IMF is,therefore,likely a consequence of both the increased ability of IMF progenitor cells to generate MKs and a decreased rate of MK apoptosis. Media conditioned (CM) by CD61+ cells generated in vitro from CD34+ cells were then assayed for the levels of growth factors and proteases. Higher levels of transforming growth factor-beta (TGF-beta) and active matrix metalloproteinase-9 (MMP9) were observed in media conditioned with IMF CD61+ cells than normal or PV CD61+ cells. Both normal and IMF CD61+ cells produced similar levels of VEGF. MK-derived TGF-B and MMP-9,therefore,likely contribute to the development of many pathological epiphenomena associated with IMF. View Publication

CRKL (CRK-like) is an adapter protein predominantly phosphorylated in cells that express the tyrosine kinase p210(BCR-ABL),the fusion product of a (9;22) chromosomal translocation causative for chronic myeloid leukemia. It has been unclear,however,whether CRKL plays a functional role in p210(BCR-ABL) transformation. Here,we show that CRKL is required for p210(BCR-ABL) to support interleukin-3-independent growth of myeloid progenitor cells and long-term outgrowth of B-lymphoid cells from fetal liver-derived hematopoietic progenitor cells. Furthermore,a synthetic phosphotyrosyl peptide that binds to the CRKL SH2 domain with high affinity blocks association of endogenous CRKL with the p210(BCR-ABL) complex and reduces c-MYC levels in K562 human leukemic cells as well as in mouse hematopoietic cells transformed by p210(BCR-ABL) or the imatinib-resistant mutant T315I. These results indicate that the function of CRKL as an adapter protein is essential for p210(BCR-ABL)-induced transformation. View Publication

The Kit receptor functions in hematopoiesis,lymphocyte development,gastrointestinal tract motility,melanogenesis,and gametogenesis. To investigate the roles of different Kit signaling pathways in vivo,we have generated knock-in mice in which docking sites for PI 3-kinase (KitY719) or Src kinase (KitY567) have been mutated. Whereas steady-state hematopoiesis is normal in KitY719F/Y719F and KitY567F/Y567F mice,lymphopoiesis is affected differentially. The KitY567F mutation,but not the KitY719F mutation,blocks pro T cell and pro B cell development in an age-dependent manner. Thus,the Src family kinase,but not the PI 3-kinase docking site in Kit,mediates a critical signal for lymphocyte development. In agreement with these results,treatment of normal mice with the Kit tyrosine kinase inhibitor imatinib (Gleevec) leads to deficits in pro T and pro B cell development,similar to those seen in KitY567F/Y567F and KitW/W mice. The two mutations do not affect embryonic gametogenesis but the KitY719F mutation blocks spermatogenesis at the spermatogonial stages and in contrast the KitY567F mutation does not affect this process. Therefore,Kit-mediated PI 3-kinase signaling and Src kinase family signaling is highly specific for different cellular contexts in vivo. View Publication