RESUMEN

The Insulin-like growth factor-I/Insulin-like growth factor-I receptor (IGF-1/IGF-1R) system is a major determinant in colorectal cancer (CRC) pathogenesis. Probiotics (Bifidobacterium longum, BF) and lycopene (LYC) have been individually researched for their beneficial effects in the prevention of CRC. However, the effect of a combined treatment of microencapsulated BF and LYC on IGF-1/IGF-1R/IGFBPs (Insulin-like growth factor-binding proteins) expression in an azoxymethane (AOM)-dextran sulfate sodium (DSS)-induced CRC model have not been demonstrated. BF was microencapsulated by the spray drying technique, with high viability, and daily gavaged with LYC for 16 weeks to CD-1 mice in an AOM-DSS model. The results indicated that BF- and BF + LYC-treated groups had significantly lower inflammation grade, tumor incidence (13-38%) and adenocarcinoma (13-14%) incidence compared to the AOM + DSS group (80%), whereas LYC treatment only protected against inflammation grade and incidence. Caecal, colonic and fecal pH and ß-glucuronidase (ß-GA) values were significantly normalized by BF and LYC. Similarly, BF and BF + LYC treatments significantly reduced both the positive rate and expression grade of IGF-1 and IGF-1R proteins and normalized Insulin-like growth factor-binding protein-3 (IGFBP3) expression. Based on intestinal parameters related to the specific colon carcinogenesis in an AOM-DSS-induced model, LYC and microencapsulated BF supplementation resulted in a significant chemopreventive potential through the modulation of IGF-1/IGF-1R system.

Asunto(s)

Anticarcinógenos/uso terapéutico , Bifidobacterium longum , Neoplasias Colorrectales/terapia , Licopeno/uso terapéutico , Probióticos/uso terapéutico , Administración Oral , Animales , Anticarcinógenos/administración & dosificación , Bifidobacterium longum/fisiología , Neoplasias Colorrectales/patología , Modelos Animales de Enfermedad , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/análisis , Licopeno/administración & dosificación , Masculino , Ratones , Ratones Endogámicos ICR , Probióticos/administración & dosificación , Receptor IGF Tipo 1/análisis

RESUMEN

The objective of this study was to investigate the gene expression of progesterone and estrogen receptor α (PR, ERα), insulin-like growth factor (IGF) 1, IGF-2, their receptor (IGFR1), IGF-binding proteins (BP) 1 to 6, insulin receptor, adiponectin receptors (AdipoR1/2), cyclooxygenase 2 (PTGS2), mucin 1 and to localize PR, ERα, IGF-1, IGFR1, PTGS2, and proliferating cellular nuclear antigen (PCNA) in the endometrium of pregnant (Day 19) Suffolk and Cheviot ewes carrying Suffolk and Cheviot embryos transferred within and reciprocally between breeds. Gene expression was determined by real-time quantitative polymerase chain reaction (RT-qPCR), and antigen determination was measured by immunohistochemistry in the luminal epithelium (LE), superficial and deep glands (SG, DG, respectively) and superficial and deep stroma. Gene expression of PR, IGF-1, IGFBP2, and IGFBP5 was higher in Suffolk than that in Cheviot ewes (P < 0.05). Greater abundance of IGF-2 and IGBP3 expression was found in Cheviot ewes carrying Cheviot embryos than Cheviot ewes carrying Suffolk embryos (P < 0.05). No staining for PR and ERα was observed in the LE, very scarce staining in SG and DG, whereas positive staining was observed in both superficial and deep stroma. No differences were found for PR staining, but Cheviot ewes had higher ERα staining intensity than Suffolk ewes (P < 0.05). Positive staining for IGF-1 was observed in all cell types except DG, and staining of IGFR1 was observed in all cell types. No differences among groups in staining were found for IGF-1 or IGFR1 in any cell type. Positive staining of PTGS2 was observed in LE and SG in all groups. An interaction between ewe and embryo breed affected PTGS2 staining (P < 0.05), whereby Cheviot ewes carrying Suffolk embryos had a lower PTGS2 staining than Suffolk ewes carrying Suffolk embryos. Positive staining of PCNA was found in LE and SG. Suffolk ewes carrying Suffolk embryos showed lower PCNA immunostaining than Cheviot ewes carrying Suffolk embryos (P < 0.05), whereas no differences were observed in ewes carrying Cheviot embryos. This study showed that gestation-related protein expression in the endometrium of Suffolk and Cheviot ewes is affected by both ewe and embryo breed at Day 19 of pregnancy.

Asunto(s)

Transferencia de Embrión/veterinaria , Endometrio/química , Endometrio/metabolismo , Expresión Génica , Ovinos/genética , Animales , Ciclooxigenasa 2/análisis , Ciclooxigenasa 2/genética , Desarrollo Embrionario/genética , Receptor alfa de Estrógeno/análisis , Receptor alfa de Estrógeno/genética , Femenino , Edad Gestacional , Inmunohistoquímica , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/análisis , Factor II del Crecimiento Similar a la Insulina/genética , Mucina-1/genética , Embarazo , Antígeno Nuclear de Célula en Proliferación/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/genética , Receptor de Insulina/genética , Receptores de Adiponectina/genética , Receptores de Progesterona/análisis , Receptores de Progesterona/genética , Especificidad de la Especie

RESUMEN

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been shown that intra-ovarian factors, such as members of the insulin-like growth factor (IGF) system, may contribute to follicular persistence. The bioavailability of IGF to initiate its response by binding to specific receptors (IGFRs) depends on interactions with related compounds, such as pregnancy-associated plasma protein A (PAPP-A). The aim of this study was to determine IGFR1 and PAPP-A expression both in follicles at different stages of development and in cysts, to evaluate the roles in the etiopathogenesis of COD in cattle. The mRNA expression of PAPP-A was higher in granulosa cells of large tertiary follicles than in cysts, whereas the protein PAPP-A present in the follicular fluid from these follicles showed no differences. Although no PAPP-A mRNA expression was detected in smaller tertiary follicles, in their follicular fluid, this protease was detected in lesser concentration than in cysts. The mRNA expression of IGFR1 was lower in granulosa cells from cystic follicles than in those from tertiary ones. However, the protein expression of this receptor presented the highest levels in cystic structures, probably to increase the possibility of IGF response. The data obtained would indicate that animals with COD have an altered regulation of the IGF system in the ovary, which could be involved in the pathogenesis of this disease in cattle.

Asunto(s)

Enfermedades de los Bovinos/fisiopatología , Quistes Ováricos/veterinaria , Proteína Plasmática A Asociada al Embarazo/fisiología , Receptor IGF Tipo 1/fisiología , Animales , Bovinos , Enfermedades de los Bovinos/etiología , Femenino , Líquido Folicular/química , Expresión Génica , Células de la Granulosa/química , Inmunohistoquímica , Quistes Ováricos/química , Quistes Ováricos/fisiopatología , Folículo Ovárico/química , Embarazo , Proteína Plasmática A Asociada al Embarazo/análisis , Proteína Plasmática A Asociada al Embarazo/genética , ARN Mensajero/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/genética

RESUMEN

Senescence is associated with hormonal imbalance and prostatic disorders. Angiogenesis is fundamental for the progression of malignant lesions and is a promising target for prostate cancer treatment. The aim was to characterize matrix metalloproteinase-9 (MMP-9) and insulin-like growth factor receptor-1 (IGFR-1) responses in the prostate during senescence and following antiangiogenic and/or androgen ablation therapies, comparing them to cancer progression features in TRAMP mice. Aged male mice (52-week-old FVB) were submitted to antiangiogenic treatments with SU5416 (6 mg/kg; i.p.) and/or TNP-470 (15 mg/kg; s.c). Finasteride (20 mg/kg; s.c.) was administered alone or associated to both inhibitors. Dorsolateral prostate was collected for light microscopy, and immunohistochemistry and Western blotting collected for MMP-9 and IGFR-1. Senescence led to inflammation and different proliferative lesions in the prostate, as well as to increased MMP-9 and IGFR-1, resembling TRAMP mice prostatic microenvironment. Antiangiogenic therapies promoted recovery and/or interruption of age-associated alterations, presenting differential effects on the molecules studied. SU5416 acted mainly on MMP-9, whereas TNP-470 showed its best influence on IGFR-1 levels. Finasteride administration, alone or in combination with antiangiogenic agents, also resulted in regression of inflammation and neoplastic lesions, besides having a negative modulatory effect on both MMP-9 and IGFR-1. We concluded that stimulated tissue remodeling and proliferative processes during senescence predisposed the prostate to malignant disorders. The combination of different agents was more effective to minimize prostatic imbalance during this period, probably due to the differential action of each drug on factors involved in cell proliferation and extracellular matrix remodeling, resulting in a broader spectrum of effects following the combined treatment.

Asunto(s)

Inhibidores de la Angiogénesis/uso terapéutico , Metaloproteinasa 9 de la Matriz/metabolismo , Enfermedades de la Próstata/tratamiento farmacológico , Enfermedades de la Próstata/metabolismo , Receptor IGF Tipo 1/metabolismo , Factores de Edad , Inhibidores de la Angiogénesis/administración & dosificación , Animales , Masculino , Metaloproteinasa 9 de la Matriz/análisis , Ratones , Ratones Endogámicos , Ratones Transgénicos , Enfermedades de la Próstata/patología , Receptor IGF Tipo 1/análisis

RESUMEN

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor derived from a pre-existing pleomorphic adenoma. It is a good model to study the evolution of carcinogenesis, starting with in situ areas to frankly invasive carcinoma. Growth factors are associated with several biological and neoplastic processes by transmembrane receptors. In order to investigate, by immunohistochemistry, the expression of some growth factors and its receptors [EGF receptor, fibroblast growth factor, fibroblast growth factor receptor 1, fibroblast growth factor receptor 2, hepatocyte growth factor, c-Met, transforming growth factor (TGF) beta1, TGFbetaR-II and insulin-like growth factor receptor 1] in the progression of CXPA, we have used ten cases of CXPA in several degrees of invasion- intracapsular, minimally and frankly invasive carcinoma- with only epithelial component. Slides were qualitatively and semi-quantitatively evaluated according to the percentage of stained tumor cells from 0 to 3 (0 = less than 10%; 1 = 10-25%; 2 = 25-50%; 3 = more than 50% of cells). Malignant epithelial cells starting with in situ areas showed stronger expression than luminal cells of pleomorphic adenoma for all antibodies. Most of the intracapsular, minimally and frankly invasive CXPA presented score 3. However, score 2 was more evident in the frankly invasive one. In small nests of invasive carcinoma, negative cells were observed probably indicating that the proliferative process is replaced by the invasive mechanism. Altogether this data infers that these factors may contribute to cell proliferation during initial phases of the tumor.

Asunto(s)

Adenocarcinoma/patología , Adenoma Pleomórfico/patología , Péptidos y Proteínas de Señalización Intercelular/análisis , Neoplasias de la Parótida/patología , Receptores de Factores de Crecimiento/análisis , Adulto , Anciano , Carcinoma in Situ/patología , Proliferación Celular , Colorantes , Progresión de la Enfermedad , Células Epiteliales/patología , Receptores ErbB/análisis , Femenino , Factores de Crecimiento de Fibroblastos/análisis , Factor de Crecimiento de Hepatocito/análisis , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Proteínas Serina-Treonina Quinasas/análisis , Proteínas Proto-Oncogénicas c-met/análisis , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/análisis , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/análisis , Receptor IGF Tipo 1/análisis , Receptor Tipo II de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/análisis , Neoplasias de la Glándula Submandibular/patología , Factor de Crecimiento Transformador beta1/análisis

RESUMEN

The purpose of this study was to analyze the interaction between caloric restriction (CR) and the dwarf mutation at the level of insulin sensitivity and signal transduction. To this end, we analyzed the in vivo status of the insulin signaling system in skeletal muscle from Ames dwarf (df/df) and normal mice fed ad libitum or subjected to short-term (20-day) CR. We measured insulin-stimulated phosphorylation of the IR and IRS-1, IRS-1-p85 association and Akt activation, and the abundance of the IR, IRS-1, p85, GLUT-4 and IGF-1 receptor in skeletal muscle. In terms of glucose homeostasis, the response to CR was different in both groups of animals. In normal animals, CR induced a significant reduction in both circulating insulin and glucose levels, while CR did not modify these parameters in df/df mice. We did not find any significant alteration in either activation or abundance of signaling molecules analyzed after short-term CR in either normal or Ames dwarf mice. We conclude that the initial adaptation to CR in normal mice is an increase in insulin sensitivity without changes in insulin signal transduction, and that this adaptation is not evidenced in df/df mice, probably since they are already hypersensitive to insulin.

Asunto(s)

Restricción Calórica , Enanismo/metabolismo , Proteínas de Homeodominio/genética , Insulina/farmacología , Músculo Esquelético/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/fisiología , Animales , Peso Corporal , Femenino , Transportador de Glucosa de Tipo 4/análisis , Proteínas Sustrato del Receptor de Insulina , Ratones , Fosfoproteínas/análisis , Fosfoproteínas/metabolismo , Fosforilación , Receptor IGF Tipo 1/análisis , Tirosina/metabolismo

RESUMEN

Chronic lymphocytic leukaemia (CLL) is characterized by the accumulation of long-lived B lymphocytes blocked in G(0/1) by impaired apoptosis. As insulin-like growth factor-I (IGF-I) is known for its antiapoptotic effects in different cell types, we investigated whether IGF-I and its receptor (IGF-IR) participate in autocrine/paracrine loops affecting the survival of CLL cells. IGF-IR protein and mRNA was present in CLL cells in 44% and 59% of patients respectively. IGF-IR expression in CLL patients was positively correlated with the expression of the antiapoptotic protein Bcl-2 and was involved in CLL cell survival in vitro. Serum IGF-I was elevated in CLL patients, but growth hormone (GH) was normal. CLL cells expressed IGF-I mRNA and secreted the growth factor in vitro. Therefore, local production of IGF-I can account for the increased levels of serum IGF-I, independently of GH, and may be related to autocrine/paracrine control of lymphocyte survival acting at IGF-IR. This is the first demonstration of IGF-IR expression in a subgroup of CLL patients and of its antiapoptotic effects in vitro, highlighting the importance of this growth factor receptor as a possible therapeutic target in CLL.

Asunto(s)

Linfocitos B/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Leucemia Linfocítica Crónica de Células B/metabolismo , Receptor IGF Tipo 1/metabolismo , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Apoptosis , Comunicación Autocrina , Linfocitos B/química , Estudios de Casos y Controles , Medios de Cultivo Condicionados/química , Femenino , Citometría de Flujo , Hormona del Crecimiento/sangre , Humanos , Factor I del Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/genética , Leucemia Linfocítica Crónica de Células B/genética , Masculino , Persona de Mediana Edad , Comunicación Paracrina , ARN Mensajero/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales Cultivadas

RESUMEN

Com o objetivo de verificar se as proteínas do sistema GH-IGF-IGFBP e o IGF-IR estão envolvidos na etiopatogenia do DM1, foram estudados 33 pacientes portadores de DM1 em diferentes fases do diagnóstico e 10 indivíduos sadios. A expressão do IGF-IR realizada através de RT-PCR nos linfócitos periféricos T e B não demonstrou diferenças nos linfócitos T quando comparados indivíduos diabéticos e controles. Observou-se uma maior expressão do IGF-IR dos linfócitos B de pacientes diabéticos em relação ao grupo controle. A avaliação do sistema GH-IGF-IGFBP não demonstrou diferença entre os grupos. Estes achados associados à presença de anticorpos suportam o papel do IGF-IR na etiopatogenia do DM1.Aiming to verify if GH-IGF-IGFBP system and IGF-IR are implicated on pathofisiology of DM1, we studied 33 patients with DM1 on different stages of diagnosis and 10 healthy subjects as control group. The RT-PCR molecular assay for IGF-IR mRNA on peripheral T and B lymphocytes didn't show differences between the groups when T cells were analyzed. We found an increase of IGF-IR mRNA expression on B cells from diabetic patients when compared the two groups. There were no differences in the GH-IGF-IGFBP system levels between the groups. Our study suggests that IGF-IR in association with Diabetes-related autoantibodies presence can be involved on pathofisiology of DM1...

Asunto(s)

Humanos , Niño , Diabetes Mellitus Tipo 1 , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/inmunología , Autoanticuerpos , Estudios de Casos y Controles , Factor I del Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos

RESUMEN

Interactions between thymocytes and thymic epithelial cell (TEC) can be modulated by growth hormone via insulin-like growth factor-1 (IGF-1). In this study, we showed IGF-1 and IGF-1 receptor mRNA expression by human and murine TEC and thymocytes. Functionally, IGF-1 stimulates extracellular matrix production by human TEC. Moreover, pretreatment of murine TEC with IGF-1 increases their adhesion to thymocytes. Interestingly, we observed an increase in the frequency of CD4-CD8-CD90+ T cells which adhered to pretreated TEC, supporting the concept that IGF-1 may also act indirectly on intrathymic T cell differentiation and migration through the thymic epithelium.

Asunto(s)

Células Epiteliales/inmunología , Factor I del Crecimiento Similar a la Insulina/genética , Receptor IGF Tipo 1/genética , Timo/citología , Timo/inmunología , Animales , Anticuerpos Monoclonales , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Adhesión Celular/inmunología , Células Cultivadas , Proteínas de la Matriz Extracelular/biosíntesis , Proteínas de la Matriz Extracelular/metabolismo , Femenino , Expresión Génica/inmunología , Hormona del Crecimiento/farmacología , Humanos , Factor I del Crecimiento Similar a la Insulina/inmunología , Factor I del Crecimiento Similar a la Insulina/farmacología , Ratones , Ratones Endogámicos BALB C , Neuroinmunomodulación/fisiología , ARN Mensajero/análisis , Receptor IGF Tipo 1/análisis , Receptor IGF Tipo 1/inmunología , Timo/química

RESUMEN

The presence of insulin-like growth factors (IGF), IGF binding proteins (IGFBP) and IGF receptor type 1 (IGF-IR) in the human corpus luteum was investigated by examining the expression and production of related proteins throughout the lifespan of the corpus luteum and the action of nitric oxide upon their production. The expression of proteins in corpora lutea from the early, mid-and late luteal phases was assessed by immunohisto-chemistry, evaluated by a semi-quantitative analysis and the functional study was performed in corpus luteum explants incubated with nitric oxide donors. IGF-I and -II and IGFBP-1 and -3 were measured in the culture media by specific immunoassays. The results showed that IGF-I and -II, IGFBP-1 to -6 and IGF-IR were detected in the human corpus luteum throughout the luteal phase. Moreover, the expression and production of IGF-I and IGFBP-1 increased progressively from corpora lutea from the early to late luteal phases (P < 0.05), whereas the expression and production of IGFBP-2, -4 and -5 were significantly higher in corpora lutea from the mid-luteal phase (P < 0.05). No differences were observed in the expression of IGF-II, IGFBP-3 and -6 and IGF-IR throughout the lifespan of the corpus luteum. However, functional studies showed that nitric oxide donors elicited a stimulatory action on production of IGF-I in corpora lutea from the early luteal phase (80%) and on production of IGFBP-1 in corpora lutea from the late luteal phase (50%) (P < 0.05), whereas production of IGF-II and IGFBP-3 was not affected by nitric oxide. In conclusion, the components of the IGF-IGFBP system are expressed in the human corpus luteum throughout its lifespan. Nitric oxide regulates IGF-I and IGFBP-1 production, indicating that the growth factors may serve, at least in part, as mediators of the action of nitric oxide in the human corpus luteum.

Asunto(s)

Cuerpo Lúteo/metabolismo , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Fase Luteínica/fisiología , Óxido Nítrico/metabolismo , Somatomedinas/metabolismo , Adulto , Arginina/farmacología , Cuerpo Lúteo/química , Cuerpo Lúteo/efectos de los fármacos , Técnicas de Cultivo , Estradiol/metabolismo , Femenino , Humanos , Inmunohistoquímica/métodos , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Proteína 2 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Proteína 4 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Proteína 4 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Proteína 5 de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Proteína 5 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/metabolismo , Factor II del Crecimiento Similar a la Insulina/análisis , Factor II del Crecimiento Similar a la Insulina/metabolismo , Donantes de Óxido Nítrico/farmacología , Progesterona/metabolismo , Receptor IGF Tipo 1/análisis , Somatomedinas/análisis

RESUMEN

Com o objetivo de verificar se o fator de crescimento insulina símile tipo I (IGF-I) e seu receptor (IGF-IR) estão implicados na instalação da leucemia mielóide crônica (LMC) foram estudados 35 pacientes portadores de LMC na fase crônica antes ou durante o tratamento com interferon `ALFA' ou hidroxiurea e 16 indivíduos sadios como grupo controle. A análise do IGF-IR realizada através da citometria de fluxo e expressão de seu RNAm pelo ensaio molecular de RT-PCR nas células sanguíneas dos pacientes com LMC não tratada não mostrou diferenças estatísticas em relação ao grupo controle. Pacientes tratados com hidroxiurea apresentaram expressão diminuída do receptor em granulócitos, monócitos e linfócitos (P`MENOR'0,01) quando comparados aos demais grupos analisados...

Asunto(s)

Humanos , Masculino , Femenino , Niño , Adolescente , Adulto , Células Madre Hematopoyéticas/efectos de los fármacos , Hidroxiurea/farmacología , Interferón-alfa/farmacología , Leucemia Mielógena Crónica BCR-ABL Positiva/fisiopatología , Receptor IGF Tipo 1/análisis , Linfocitos B , Enfermedad Crónica , Citometría de Flujo , Linfocitos T

RESUMEN

In the present study, we present evidence about the cellular functions of KIF2, a kinesin-like superfamily member having a unique structure in that its motor domain is localized at the center of the molecule (Noda Y., Y. Sato-Yoshitake, S. Kondo, M. Nangaku, and N. Hirokawa. 1995. J. Cell Biol. 129:157-167.). Using subcellular fractionation techniques, isopicnic sucrose density centrifugation of microsomal fractions from developing rat cerebral cortex, and immunoisolation with KIF2 antibodies, we have now identified a type of nonsynaptic vesicle that associates with KIF2. This type of organelle lacks synaptic vesicle markers (synapsin, synaptophysin), amyloid precursor protein, GAP-43, or N-cadherin. On the other hand, it contains betagc, which is a novel variant of the beta subunit of the IGF-1 receptor, which is highly enriched in growth cone membranes. Both betagc and KIF2 are upregulated by NGF in PC12 cells and highly concentrated in growth cones of developing neurons. We have also analyzed the consequences of KIF2 suppression by antisense oligonucleotide treatment on nerve cell morphogenesis and the distribution of synaptic and nonsynaptic vesicle markers. KIF2 suppression results in a dramatic accumulation of betagc within the cell body and in its complete disappearance from growth cones; no alterations in the distribution of synapsin, synaptophysin, GAP-43, or amyloid percursor protein are detected in KIF2-suppressed neurons. Instead, all of them remained highly enriched at nerve terminals. KIF2 suppression also produces a dramatic inhibition of neurite outgrowth; this phenomenon occurs after betagc has disappeared from growth cones. Taken collectively, our results suggest an important role for KIF2 in neurite extension, a phenomenon that may be related with the anterograde transport of a type of nonsynaptic vesicle that contains as one of its components a growth cone membrane receptor for IGF-1, a growth factor implicated in nerve cell development.

Asunto(s)

Cinesinas/fisiología , Neuritas/fisiología , Neuronas/fisiología , Orgánulos/metabolismo , Precursor de Proteína beta-Amiloide/análisis , Animales , Anticuerpos Monoclonales , Corteza Cerebral/química , Proteína GAP-43 , Cinesinas/análisis , Cinesinas/genética , Cinesinas/inmunología , Glicoproteínas de Membrana/análisis , Factores de Crecimiento Nervioso/farmacología , Proteínas del Tejido Nervioso/análisis , Neuronas/citología , Oligonucleótidos Antisentido/farmacología , Orgánulos/química , Células PC12 , Ratas , Receptor IGF Tipo 1/análisis , Fracciones Subcelulares/química , Sinapsinas/análisis , Vesículas Sinápticas/química , Vesículas Sinápticas/metabolismo , Sinaptofisina/análisis , Tionucleótidos/farmacología , Regulación hacia Arriba

RESUMEN

Insulin-like growth factor-I (IGF-I) receptors are characterized in several animal and human tissues. IGF-I receptor studies performed in erythrocytes to assess IGF-I receptor status at target-cell tissues are potentially useful for clinical studies, since tissue biopsies or cultures are not required. However, validation of results is challenged by some investigators on the basis of discrepancies described in comparative studies with other cell types, probably related to populations of different cell ages affecting binding to red blood cells (RBCs). By correcting cell age for creatine, we studied IGF-I receptor status in 24 normal subjects (11 adults and 13 children, eight prepubertal and five pubertal) and 33 patients with pathologic conditions (five adult acromegalics, six children with pituitary dwarfism, and 22 type I diabetic children, 15 prepubertal and seven pubertal). Acromegalic patients with higher plasma IGF-I and insulin levels presented lower IGF-I specific binding ([Bo] mean +/- SEM, 6.1% +/- 0.8%) and affinity ([ED50] 28.5 +/- 2.2 ng/mL) than normal adults (Bo, 10.9% +/- 0.7%; ED50, 16.4 +/- 0.9 ng/mL; P < .001), and growth hormone (GH)-deficient children showed higher IGF-I binding 24.6% +/- 1.7%, P < .001) without significant affinity alterations than normal prepubertal children (Bo, 14.7% +/- 1.0%). Both prepubertal and pubertal type I diabetic children with higher GH levels presented decreased IGF-I binding (11.4% +/- 0.9% for prepubertal, P < .05; 10.0% +/- 1.1% for pubertal, P < .05) to RBC receptors in comparison to the respective control group (14.7% +/- 10% and 14.9% +/- 1.3%, prepubertal and pubertal, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Acromegalia/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Eritrocitos/metabolismo , Hormona del Crecimiento/deficiencia , Receptor IGF Tipo 1/análisis , Acromegalia/sangre , Acromegalia/fisiopatología , Adolescente , Adulto , Antropometría , Niño , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/fisiopatología , Femenino , Humanos , Insulina/sangre , Masculino , Ensayo de Unión Radioligante