技术资料

We identify the tumor necrosis factor receptor superfamily 25 (TNFRSF25)/TNFSF15 pair as critical trigger for allergic lung inflammation,which is a cardinal feature of asthma. TNFRSF25 (TNFR25) signals are required to exert T helper cell 2 (Th2) effector function in Th2-polarized CD4 cells and co-stimulate interleukin (IL)-13 production by glycosphingolipid-activated NKT cells. In vivo,antibody blockade of TNFSF15 (TL1A),which is the ligand for TNFR25,inhibits lung inflammation and production of Th2 cytokines such as IL-13,even when administered days after airway antigen exposure. Similarly,blockade of TNFR25 by a dominant-negative (DN) transgene,DN TNFR25,confers resistance to lung inflammation in mice. Allergic lung inflammation-resistant,NKT-deficient mice become susceptible upon adoptive transfer of wild-type NKT cells,but not after transfer of DN TNFR25 transgenic NKT cells. The TNFR25/TL1A pair appears to provide an early signal for Th2 cytokine production in the lung,and therefore may be a drug target in attempts to attenuate lung inflammation in asthmatics. View Publication

The clinical success of stem cell therapy for myocardial repair hinges on a better understanding of cardiac fate mechanisms. We have identified small molecules involved in cardiac fate by screening a chemical library for activators of the signature gene Nkx2.5,using a luciferase knockin bacterial artificial chromosome (BAC) in mouse P19CL6 pluripotent stem cells. We describe a family of sulfonyl-hydrazone (Shz) small molecules that can trigger cardiac mRNA and protein expression in a variety of embryonic and adult stem/progenitor cells,including human mobilized peripheral blood mononuclear cells (M-PBMCs). Small-molecule-enhanced M-PBMCs engrafted into the rat heart in proximity to an experimental injury improved cardiac function better than control cells. Recovery of cardiac function correlated with persistence of viable human cells,expressing human-specific cardiac mRNAs and proteins. Shz small molecules are promising starting points for drugs to promote myocardial repair/regeneration by activating cardiac differentiation in M-PBMCs. View Publication

Pluripotent cells can be derived from fibroblasts by ectopic expression of defined transcription factors. A fundamental unresolved question is whether terminally differentiated cells can be reprogrammed to pluripotency. We utilized transgenic and inducible expression of four transcription factors (Oct4,Sox2,Klf4,and c-Myc) to reprogram mouse B lymphocytes. These factors were sufficient to convert nonterminally differentiated B cells to a pluripotent state. However,reprogramming of mature B cells required additional interruption with the transcriptional state maintaining B cell identity by either ectopic expression of the myeloid transcription factor CCAAT/enhancer-binding-protein-alpha (C/EBPalpha) or specific knockdown of the B cell transcription factor Pax5. Multiple iPS lines were clonally derived from both nonfully and fully differentiated B lymphocytes,which gave rise to adult chimeras with germline contribution,and to late-term embryos when injected into tetraploid blastocysts. Our study provides definite proof for the direct nuclear reprogramming of terminally differentiated adult cells to pluripotency. View Publication

This unit describes the production of monoclonal antibodies beginning with immunization and cell fusion and selection. Support protocols are provided for screening primary hybridoma supernatants for antibodies of desired specificity,establishment of stable hybridoma lines,cloning of these B cell lines by limiting dilution to obtain monoclonal lines,and preparation of cloning/expansion medium. An alternate protocol describes cell fusion and one-step selection and cloning of hybridomas utilizing a semi-solid methylcellulose-based medium (ClonaCell-HY). View Publication

The cFMS (cellular homolog of the V-FMS oncogene product of the Susan McDonough strain of feline sarcoma virus) (Proc Natl Acad Sci U S A 83:3331-3335,1986) kinase inhibitor 5-(3-methoxy-4-((4-methoxybenzyl)oxy)benzyl)pyrimidine-2,4-diamine (GW2580) inhibits colony-stimulating factor (CSF)-1-induced monocyte growth and bone degradation in vitro and inhibits CSF-1 signaling through cFMS kinase in 4-day models in mice (Proc Natl Acad Sci U S A 102:16078,2005). In the present study,the kinase selectivity of GW2580 was further characterized,and the effects of chronic treatment were evaluated in normal and arthritic rats. GW2580 selectively inhibited cFMS kinase compared with 186 other kinases in vitro and completely inhibited CSF-1-induced growth of rat monocytes,with an IC(50) value of 0.2 microM. GW2580 dosed orally at 25 and 75 mg/kg 1 and 5 h before the injection of lipopolysaccharide inhibited tumor necrosis factor-alpha production by 60 to 85%,indicating a duration of action of at least 5 h. In a 21-day adjuvant arthritis model,GW2580 dosed twice a day (b.i.d.) from days 0 to 21,7 to 21,or 14 to 21 inhibited joint connective tissue and bone destruction as assessed by radiology,histology and bone mineral content measurements. In contrast,GW2580 did not affect ankle swelling in the adjuvant model nor did it affect ankle swelling in a model where local arthritis is reactivated by peptidoglycan polysaccharide polymers. GW2580 administered to normal rats for 21 days showed no effects on tissue histology and only modest changes in serum clinical chemistry and blood hematology. In conclusion,GW2580 was effective in preserving joint integrity in the adjuvant arthritis model while showing minimal effects in normal rats. View Publication

Neuropilin-1 (Nrp1) is a multifunctional protein,identified principally as a receptor for the class 3 semaphorins and members of the vascular endothelial growth factor (VEGF) family,but it is capable of other interactions. It is a marker of regulatory T cells (Tr),which often carry Nrp1 and latency-associated peptide (LAP)-TGF-beta1 (the latent form). The signaling TGF-beta1 receptors bind only active TGF-beta1,and we hypothesized that Nrp1 binds the latent form. Indeed,we found that Nrp1 is a high-affinity receptor for latent and active TGF-beta1. Free LAP,LAP-TGF-beta1,and active TGF-beta1 all competed with VEGF165 for binding to Nrp1. LAP has a basic,arginine-rich C-terminal motif similar to VEGF and peptides that bind to the b1 domain of Nrp1. A C-terminal LAP peptide (QSSRHRR) bound to Nrp1 and inhibited the binding of VEGF and LAP-TGF-beta1. We also analyzed the effects of Nrp1/LAP-TGF-beta1 coexpression on T cell function. Compared with Nrp1(-) cells,sorted Nrp1+ T cells had a much greater capacity to capture LAP-TGF-beta1. Sorted Nrp1(-) T cells captured soluble Nrp1-Fc,and this increased their ability to capture LAP-TGF-beta1. Conventional CD4+CD25(-)Nrp1(-) T cells coated with Nrp1-Fc/LAP-TGF-beta1 acquired strong Tr activity. Moreover,LAP-TGF-beta was activated by Nrp1-Fc and also by a peptide of the b2 domain of Nrp1 (RKFK; similar to a thrombospondin-1 peptide). Breast cancer cells,which express Nrp1,also captured and activated LAP-TGF-beta1 in a Nrp1-dependent manner. Thus,Nrp1 is a receptor for TGF-beta1,activates its latent form,and is relevant to Tr activity and tumor biology. View Publication

The hierarchical progression of stem and progenitor cells to their more-committed progeny is mediated through cell-to-cell signaling pathways and intracellular transcription factor activity. However,the mechanisms that govern the genetic networks underlying lineage fate decisions and differentiation programs remain poorly understood. Here we show how integration of Bmp4 signaling and Gata factor activity controls the progression of hematopoiesis,as exemplified by the regulation of Eklf during establishment of the erythroid lineage. Utilizing transgenic reporter assays in differentiating mouse embryonic stem cells as well as in the murine fetal liver,we demonstrate that Eklf expression is initiated prior to erythroid commitment during hematopoiesis. Applying phylogenetic footprinting and in vivo binding studies in combination with newly developed loss-of-function technology in embryoid bodies,we find that Gata2 and Smad5 cooperate to induce Eklf in a progenitor population,followed by a switch to Gata1-controlled regulation of Eklf transcription upon erythroid commitment. This stage- and lineage-dependent control of Eklf expression defines a novel role for Eklf as a regulator of lineage fate decisions during hematopoiesis. View Publication

The majority of BRCA1-associated breast cancers are basal cell-like,which is associated with a poor outcome. Using a spontaneous mouse mammary tumor model,we show that platinum compounds,which generate DNA breaks during the repair process,are more effective than doxorubicin in Brca1/p53-mutated tumors. At 0.5 mg/kg of daily cisplatin treatment,80% primary tumors (n = 8) show complete pathologic response. At greater dosages,100% show complete response (n = 19). However,after 2 to 3 months of complete remission following platinum treatment,tumors relapse and become refractory to successive rounds of treatment. Approximately 3.8% to 8.0% (mean,5.9%) of tumor cells express the normal mammary stem cell markers,CD29(hi)24(med),and these cells are tumorigenic,whereas CD29(med)24(-/lo) and CD29(med)24(hi) cells have diminished tumorigenicity or are nontumorigenic,respectively. In partially platinum-responsive primary transplants,6.6% to 11.0% (mean,8.8%) tumor cells are CD29(hi)24(med); these populations significantly increase to 16.5% to 29.2% (mean,22.8%; P textless 0.05) in platinum-refractory secondary tumor transplants. Further,refractory tumor cells have greater colony-forming ability than the primary transplant-derived cells in the presence of cisplatin. Expression of a normal stem cell marker,Nanog,is decreased in the CD29(hi)24(med) populations in the secondary transplants. Top2A expression is also down-regulated in secondary drug-resistant tumor populations and,in one case,was accompanied by genomic deletion of Top2A. These studies identify distinct cancer cell populations for therapeutic targeting in breast cancer and implicate clonal evolution and expansion of cancer stem-like cells as a potential cause of chemoresistance. View Publication

Aberrant expression and/or activity of members of the Src family of nonreceptor protein tyrosine kinases (SFK) are commonly observed in progressive stages of human tumors. In prostate cancer,two SFKs (Src and Lyn) have been specifically implicated in tumor growth and progression. However,there are no data in preclinical models demonstrating potential efficacy of Src inhibitors against prostate cancer growth and/or metastasis. In this study,we used the small molecule SFK/Abl kinase inhibitor dasatinib,currently in clinical trials for solid tumors,to examine in vitro and in vivo effects of inhibiting SFKs in prostate tumor cells. In vitro,dasatinib inhibits both Src and Lyn activity,resulting in decreased cellular proliferation,migration,and invasion. In orthotopic nude mouse models,dasatinib treatment effectively inhibits expression of activated SFKs,resulting in inhibition of both tumor growth and development of lymph node metastases in both androgen-sensitive and androgen-resistant tumors. In primary tumors,SFK inhibition leads to decreased cellular proliferation (determined by immunohistochemistry for proliferating cell nuclear antigen). In vitro,small interfering RNA (siRNA)-mediated inhibition of Lyn affects cellular proliferation; siRNA inhibition of Src affects primarily cellular migration. Therefore,we conclude that SFKs are promising therapeutic targets for treatment of human prostate cancer and that Src and Lyn activities affect different cellular functions required for prostate tumor growth and progression. View Publication

Evi-1 is a zinc-finger transcriptional factor whose inappropriate expression leads to leukemic transformation in mice and humans. Recently,it has been shown that Evi-1 regulates proliferation of hematopoietic stem/progenitor cells at embryonic stage via GATA-2 up-regulation; however,detailed mechanisms underlying Evi-1-mediated early hematopoiesis are not fully understood. We therefore evaluated hematopoietic potential of Evi-1 mutants using a cultivation system of murine para-aortic splanchnopleural (P-Sp) regions,and found that both the first zinc finger domain and the acidic domain were required for Evi-1-mediated hematopoiesis. The hematopoietic potential of Evi-1 mutants was likely to be related to its ability to up-regulate GATA-2 expression. We also showed that the decreased colony forming capacity of Evi-1-deficient P-Sp cells was successfully recovered by inhibition of TGF-b signaling,using ALK5 inhibitor or retroviral transfer of dominant-negative-type Smad3. Our findings suggest that Evi-1 promotes hematopoietic stem/progenitor expansion at the embryonic stage through up-regulation of GATA-2 and repression of TGF-beta signaling. View Publication

T-bet and STAT4 play critical roles in helper T cell differentiation,especially for Th1 cells. However,it is still unknown about the relative importance and redundancy of T-bet and STAT4 for Th1 differentiation. It is also unknown about their independent role of T-bet and STAT4 in the regulation of allergic airway inflammation. In this study,we addressed these issues by comparing T-bet-deficient (T-bet(-/-)) mice,STAT4(-/-) mice,and T-bet- and STAT4-double-deficient (T-bet(-/-)STAT4(-/-)) mice on the same genetic background. Th1 differentiation was severely decreased in T-bet(-/-) mice and STAT4(-/-) mice as compared with that in wild-type mice,but Th1 differentiation was still observed in T-bet(-/-) mice and STAT4(-/-) mice. However,Th1 cells were hardly detected in T-bet(-/-)STAT4(-/-) mice. In contrast,the maintenance of Th17 cells was enhanced in T-bet(-/-) mice but was reduced in STAT4(-/-) mice and T-bet(-/-)STAT4(-/-) mice. In vivo,Ag-induced eosinophil and neutrophil recruitment into the airways was enhanced in T-bet(-/-) mice but was attenuated in STAT4(-/-) mice and T-bet(-/-)STAT4(-/-) mice. Ag-induced IL-17 production in the airways was also diminished in STAT4(-/-) mice and T-bet(-/-)STAT4(-/-) mice. These results indicate that STAT4 not only plays an indispensable role in T-bet-independent Th1 differentiation but also is involved in the maintenance of Th17 cells and the enhancement of allergic airway inflammation. View Publication

BRAF-activating mutations have been reported in several types of cancer,including melanoma ( approximately 70% of cases),thyroid (30-70%),ovarian (15-30%),and colorectal cancer (5-20%). Mutant BRAF has constitutive kinase activity and causes hyperactivation of the mitogen-activated protein kinase pathway. BRAF silencing induces regression of melanoma xenografts,indicating the essential role of BRAF for cell survival. We set up an inducible short hairpin RNA system to compare the role of oncogenic BRAF in thyroid carcinoma versus melanoma cells. Although BRAF knockdown led to apoptosis in the melanoma cell line A375,the anaplastic thyroid carcinoma cell ARO underwent growth arrest upon silencing,with little or no cell death. Reexpression of the thyroid differentiation marker,sodium iodide symporter,was induced after long-term silencing. The different outcome of BRAF down-regulation in the two cell lines was associated with an opposite regulation of p21(CIP1/WAF1) expression levels in response to the block of the BRAF mitogenic signal. These results were confirmed using a specific BRAF small-molecule inhibitor,PLX4032. Restoration of p21(CIP1/WAF1) expression rescued melanoma cells from death. Altogether,our data indicate that oncogenic BRAF inhibition can have a different effect on cell fate depending on the cellular type. Furthermore,we suggest that a BRAF-independent mechanism of cell survival exists in anaplastic thyroid cancer cells. View Publication