RESUMO
Claudin-1 (CL-1) is responsible for the paracellular barrier function of glomerular parietal epithelial cells (PEC) in kidneys, but the role of CL-1 in proximal tubules remains to be elucidated. In this study, to evaluate CL-1 as a potential therapeutic drug target for chronic kidney disease, we investigated change of CL-1 expression in the proximal tubules of diseased kidney and elucidated the factors that induced this change. We established Alport mice as a kidney disease model and investigated the expression of CL-1 in diseased kidney using quantitative PCR and immunohistochemistry (IHC). Compared to wild type mice, Alport mice showed significant increases in plasma creatinine, urea nitrogen and urinary albumin excretion. CL-1 mRNA was increased significantly in the kidney cortex and CL-1 was localized on the adjacent cell surfaces of PECs and proximal tubular epithelial cells. The infiltration of inflammatory cells around proximal tubules and a significant increase in TNF-α mRNA were observed in diseased kidneys. To reveal factors that induce CL-1, we analyzed the induction of CL-1 by albumin or tumor necrosis factor (TNF)-α in human proximal tubular cells (RPTEC/TERT1) using quantitative PCR and Western blotting. TNF-α increased CL-1 expression dose-dependently, though albumin did not affect CL-1 expression in RPTEC/TERT1. In addition, both CL-1 and TNF-α expression were significantly increased in UUO mice, which are commonly used as a model of tubulointerstitial inflammation without albuminuria. These results indicate that CL-1 expression is induced by inflammation, not by albuminuria in diseased proximal tubules. Moreover, we examined the localization of CL-1 in the kidney of IgA nephropathy patients by IHC and found CL-1 expression was also elevated in the proximal tubular cells. Taken together, CL-1 expression is increased in the proximal tubular epithelial cells of diseased kidney. Inflammatory cells around the tubular epithelium may produce TNF-α which in turn induces CL-1 expression.
Assuntos
Glomerulonefrite por IGA , Fator de Necrose Tumoral alfa , Albuminas/metabolismo , Albuminúria/patologia , Animais , Claudina-1/genética , Claudina-1/metabolismo , Feminino , Glomerulonefrite por IGA/patologia , Humanos , Inflamação/patologia , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Agonistic antibodies targeting CD137 have been clinically unsuccessful due to systemic toxicity. Because conferring tumor selectivity through tumor-associated antigen limits its clinical use to cancers that highly express such antigens, we exploited extracellular adenosine triphosphate (exATP), which is a hallmark of the tumor microenvironment and highly elevated in solid tumors, as a broadly tumor-selective switch. We generated a novel anti-CD137 switch antibody, STA551, which exerts agonistic activity only in the presence of exATP. STA551 demonstrated potent and broad antitumor efficacy against all mouse and human tumors tested and a wide therapeutic window without systemic immune activation in mice. STA551 was well tolerated even at 150 mg/kg/week in cynomolgus monkeys. These results provide a strong rationale for the clinical testing of STA551 against a broad variety of cancers regardless of antigen expression, and for the further application of this novel platform to other targets in cancer therapy. SIGNIFICANCE: Reported CD137 agonists suffer from either systemic toxicity or limited efficacy against antigen-specific cancers. STA551, an antibody designed to agonize CD137 only in the presence of extracellular ATP, inhibited tumor growth in a broad variety of cancer models without any systemic toxicity or dependence on antigen expression.See related commentary by Keenan and Fong, p. 20.This article is highlighted in the In This Issue feature, p. 1.
Assuntos
Trifosfato de Adenosina , Neoplasias , Animais , Anticorpos Monoclonais/farmacologia , Antígenos de Neoplasias , Imunoterapia , Camundongos , Neoplasias/tratamento farmacológico , Microambiente Tumoral , Membro 9 da Superfamília de Receptores de Fatores de Necrose TumoralRESUMO
T cell-mediated immunotherapy is an attractive strategy for treatment in various disease areas. In this therapeutic approach, the CD3 complex is one of the key molecules to modulate T cell functions; however, in many cases, we cannot evaluate the drug candidates in animal experiments because the therapeutics, usually monoclonal antibodies specific to human CD3, cannot react to mouse endogenous Cd3. Although immunodeficient mice transfused with human hematopoietic stem or precursor cells, known as humanized mice, are available for these studies, mice humanized in this manner are not completely immune competent. In this study we have succeeded in establishing a novel mouse strain in which all the three components of the Cd3 complex - Cd3ε, Cd3δ, and Cd3γ - are replaced by their human counterparts, CD3E, CD3D, and CD3G. Basic immunological assessments have confirmed that this strain of human CD3 EDG-replaced mice are entirely immune competent, and we have also demonstrated that a bispecific antibody that simultaneously binds to human CD3 and a tumor-associated antigen (e.g. ERBB2 or GPC3) can be evaluated in human CD3 EDG-replaced mice engrafted with tumors. Our mouse model provides a novel means to evaluate the in vivo efficacy of human CD3-mediated therapy.
Assuntos
Complexo CD3/imunologia , Linfócitos T/imunologia , Animais , Anticorpos Biespecíficos/imunologia , Anticorpos Monoclonais/imunologia , Células-Tronco Hematopoéticas/imunologia , Humanos , CamundongosRESUMO
For clinical trials of therapeutic monoclonal antibodies (mAbs) to be successful, their efficacy needs to be adequately evaluated in preclinical experiments. However, in many cases it is difficult to evaluate the candidate mAbs using animal disease models because of lower cross-reactivity to the orthologous target molecules. In this study we have established a novel humanized Castleman's disease mouse model, in which the endogenous interleukin-6 receptor gene is successfully replaced by human IL6R, and human IL6 is overexpressed. We have also demonstrated the therapeutic effects of an antibody that neutralizes human IL6R, tocilizumab, on the symptoms in this mouse model. Plasma levels of human soluble IL6R and human IL6 were elevated after 4-week treatment of tocilizumab in this mouse model similarly to the result previously reported in patients treated with tocilizumab. Our mouse model provides us with a novel means of evaluating the in vivo efficacy of human IL6R-specific therapeutic agents.
Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Receptores de Interleucina-6/metabolismo , Animais , Anticorpos Monoclonais Humanizados/uso terapêutico , Hiperplasia do Linfonodo Gigante/tratamento farmacológico , Hiperplasia do Linfonodo Gigante/metabolismo , Hiperplasia do Linfonodo Gigante/patologia , Modelos Animais de Doenças , Feminino , Técnicas de Introdução de Genes , Humanos , Interleucina-6/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Interleucina-6/sangue , Receptores de Interleucina-6/genéticaRESUMO
Diabetic nephropathy (DN) is the most important chronic kidney disease. We previously reported that Smad1 transcriptionally regulates the expression of extracellular matrix in DN. Phenotypic change in mesangial cells (MCs) is a key pathologic event in the progression of DN. The aim of this study is to investigate a novel mechanism underlying chondrogenic phenotypic change in MCs that results in the development of DN. MCs showed chondrogenic potential in a micromass culture, and BMP4 induced the expression of chondrocyte markers (SRY-related HMG Box 9 (SOX9) and type II collagen (COL2)). Advanced glycation end products induced the expression of chondrocyte marker proteins downstream from the BMP4-Smad1 signaling pathway in MCs. In addition, hypoxia also induced the expression of BMP4, hypoxia-inducible factor-1α (HIF-1α), and chondrocyte markers. Overexpression of SOX9 caused ectopic expression of proteoglycans and COL2 in MCs. Furthermore, forced expression of Smad1 induced chondrocyte markers as well. Dorsomorphin inhibited these inductions. Glomerular expressions of HIF-1α, BMP4, and chondrocyte markers were observed in diabetic nephropathy mice. These positive stainings were observed in mesangial sclerotic lesions. SOX9 was partially colocalized with HIF-1α and BMP4 in diabetic glomeruli. BMP4 knock-in transgenic mice showed not only similar pathological lesions to DN, but also the induction of chondrocyte markers in the sclerotic lesions. Here we demonstrate that HIF-1α and BMP4 induce SOX9 expression and subsequent chondrogenic phenotype change in DN. The results suggested that the transdifferentiation of MCs into chondrocyte-like cells in chronic hypoxic stress may result in irreversible structural change in DN.
Assuntos
Antígenos de Diferenciação/biossíntese , Transdiferenciação Celular , Condrócitos/metabolismo , Nefropatias Diabéticas/metabolismo , Regulação da Expressão Gênica , Mesângio Glomerular/metabolismo , Fatores de Transcrição SOX9/biossíntese , Animais , Antígenos de Diferenciação/genética , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 4/metabolismo , Linhagem Celular , Condrócitos/patologia , Colágeno Tipo II/biossíntese , Colágeno Tipo II/genética , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Mesângio Glomerular/patologia , Produtos Finais de Glicação Avançada/genética , Produtos Finais de Glicação Avançada/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Camundongos , Camundongos Transgênicos , Fatores de Transcrição SOX9/genética , Proteína Smad1/genética , Proteína Smad1/metabolismoRESUMO
We have been investigating the functional display of multipass membrane protein such as transporter or G-protein coupled receptor on the budded baculovirus (BV). We tested the use of a viral envelope protein gp64 transgenic mouse for the direct immunization of these membrane proteins displayed on BVs. The gp64 transgenic mice showed only a weak response to virus compared to wild type BALB/c mice. Immunizing gp64 transgenic mice with the BV expressing peptide transporter PepT1, we obtained 47 monoclonal antibodies (mAbs). These mAbs were specific to the PepT1 on the pancreatic cancer cells AsPC-1 by fluorocytometric analysis and exhibited antibody-dependent cellular cytotoxicity or complement-dependent cytotoxicity to AsPC-1. We also generated 7 mAbs by immunizing gp64 transgenic mice on a CCR2-deficient background with the BV expressing chemokine receptor CCR2 together with partially purified CCR2. These mAbs possessed specific binding to CCR2 in CHO cells on fluorocytometric analysis, and exhibited neutralizing activities for ligand-dependent inhibition of cyclic AMP production. This method provides a powerful tool for the generation of therapeutic/diagnostic mAbs against membrane proteins.
Assuntos
Anticorpos Monoclonais/biossíntese , Baculoviridae/genética , Moléculas de Adesão Celular/genética , Glicoproteínas de Membrana/genética , Proteínas de Membrana/imunologia , Biblioteca de Peptídeos , Proteínas do Envelope Viral/genética , Proteínas Virais/genética , Animais , Baculoviridae/metabolismo , Células CHO , Linhagem Celular Tumoral , Cricetinae , Cricetulus , Imunização , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Transportador 1 de Peptídeos , Receptores CCR2 , Receptores de Quimiocinas/imunologia , Simportadores/imunologia , Proteínas do Envelope Viral/imunologiaRESUMO
Deletion mutations constitute an important class of mutations that may result in a variety of human diseases, including cancer. Although many chemicals and ionizing radiations induce deletions, this class of mutation has been poorly characterized at the molecular level, particularly in vivo. Here we report the molecular nature of deletions as well as base substitutions induced by antitumor antibiotic mitomycin C (MMC) in the bone marrow using a novel transgenic mouse, gpt delta. In this mouse model, deletions and point mutations in lambda DNA integrated in the chromosome are individually selected as Spi(-) (sensitive to P2 interference) phages and 6-thioguanine-resistant bacterial colonies, respectively. The mice were treated with MMC (1 mg/kg/day) for five consecutive days. One week after the last treatment, lambda phage was rescued from the genomic DNA of the bone marrow by in vitro packaging reactions and subjected to Spi(-) and 6-thioguanine selections. The mutant frequency of Spi(-) with large deletions increased more than 20-fold over that of the control. Molecular sizes of the large deletions were mostly more than 2,000 base pairs. The large deletions frequently occurred between two short direct repeat sequences from 2 to 6 base pairs, suggesting that they are generated during the end-joining repair of double-strand breaks induced by interstrand cross-links in DNA. In 6-thioguanine selection, tandem-base substitutions, such as 5'-GG-3' to 5'-AT-3', were induced. It highlights the relevance of intrastrand cross-links as genotoxic lesions. Previous in vitro studies report the induction of single-base substitutions and single-base deletions by MMC. However, no such mutations were identified in vivo. Thus, our results strongly caution that in vitro mutation spectra do not necessarily reflect genotoxic events in vivo and emphasize the importance of transgenic rodent genotoxicity assays to examine the roles of DNA adducts in mutagenesis and carcinogenesis.
Assuntos
Antibióticos Antineoplásicos/toxicidade , Pareamento Incorreto de Bases , Medula Óssea/efeitos dos fármacos , DNA/genética , Mitomicina/toxicidade , Deleção de Sequência , Animais , Bacteriófago lambda/genética , Sequência de Bases , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Dados de Sequência Molecular , Testes de Mutagenicidade , Mutagênicos/toxicidadeRESUMO
Peutz-Jeghers syndrome (PJS) is a dominantly inherited human disorder characterized by gastrointestinal hamartomatous polyposis and mucocutaneous melanin pigmentation. LKB1 (STK11) serine/threonine kinase is the product of the causative gene of PJS, which has been mapped to chromosome 19p13.3. However, several studies have produced results that are not consistent with a link between LKB1 gene mutation and PJS. We constructed a knockout gene mutation of Lkb1 to determine whether it is the causative gene of PJS and to examine the biological role of the Lkb1 gene. Lkb1(-/-) mice died in utero between 8.5 and 9.5 days postcoitum. At 9.0 days postcoitum, Lkb1(-/-) embryos were generally smaller than their age-matched littermates, showed developmental retardation, and did not undergo embryonic turning. Multiple gastric adenomatous polyps were observed in 10- to 14-month-old Lkb1(+/-) mice. Our results indicate that functional Lkb1 is required for normal embryogenesis and that it is related to tumor development. The Lkb1(+/-) mouse is suitable for studying molecular mechanism underlying the development of inherited gastric tumors in PJS.
Assuntos
Desenvolvimento Embrionário e Fetal/genética , Pólipos Intestinais/genética , Síndrome de Peutz-Jeghers/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Quinases Ativadas por AMP , Animais , Sequência de Bases , Northern Blotting , Clonagem Molecular , Primers do DNA , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Transgenic mice carrying human IL-6 cDNA fused with a murine major histocompatibility class-I promoter (H-2L(d)) were serially administered with anti-interleukin-6 receptor (IL-6R) monoclonal antibody (mAb), MR16-1, from the age of 4 weeks to estimate its efficacy on a variety of disorders developed in these mice, most of which are similar to the disorders associated with Castleman's disease. In the control mice treated with isotype-matched mAb, a massive and multiple IgG1 plasmacytosis, mesangial proliferative glomerulonephritis, leukocytosis, thrombocytosis, anemia and abnormalities of blood chemical parameters have developed in accordance with the elevation of serum IL-6, and 50% of mice have died of renal failure by 18 weeks of age. In contrast, the treatment with MR16-1 prevented all these symptoms and prolonged the lifetime of the majority of the mice. Thus, the constitutive overexpression of IL-6 caused various disorders, and the treatment with anti-IL-6R mAb completely prevented from these symptoms. These results clearly confirm that IL-6 indeed plays an essential role in the pathogenesis of a variety of disorders. Furthermore, anti-IL-6R mAb could provide novel therapy for Castleman's disease and MR16-1 should be a useful tool to estimate therapeutic potential of IL-6 antagonists in a variety of murine models for human disease.