RESUMO
OBJECTIVE: Targeting the glucagon-like peptide-1 receptor with radiolabeled exendin is a very promising method to noninvasively determine the ß cell mass in the pancreas, which is needed to unravel the pathophysiology of type 1 and type 2 diabetes. The present study aimed to explore the effects of both hyperglycemia and insulitis on the uptake of exendin in a spontaneous type 1 diabetes mouse model, nonobese diabetic (NOD) mice. METHODS: NOD mice (n = 75, 7-21 weeks old) were injected intravenously with [111In]In-DTPA-exendin-3, and single-photon emission computed tomography (SPECT) images were acquired 1 h pi. The pancreatic accumulation of [111In]In-DTPA-exendin-3 was quantified in vivo using SPECT and by ex vivo counting and correlated to the ß cell mass (BCM). The influence of insulitis and hyperglycemia on the exendin uptake was assessed. RESULTS: The pancreas could be visualized longitudinally using SPECT. A linear correlation was found between the BCM (%) and pancreatic uptake (%ID/g) as measured by ex vivo counting (Pearson r = 0.64, p < 0.001), which was not affected by either insulitis (Pearson r = 0.66, p = 0.83) or hyperglycemia (Pearson r = 0.57, p = 0.51). Biodistribution and ex vivo autoradiography revealed remaining [111In]In-DTPA-exendin-3 uptake in the pancreas despite total ablation of BCM. CONCLUSIONS: Despite hyperglycemia and severe insulitis, we have found a good correlation between BCM and pancreatic exendin uptake, even in a suboptimal model with relatively high background activity.
Assuntos
Diabetes Mellitus Tipo 1/metabolismo , Hiperglicemia/metabolismo , Células Secretoras de Insulina/metabolismo , Peptídeos/metabolismo , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Animais , Autorradiografia , Diabetes Mellitus Tipo 1/diagnóstico por imagem , Modelos Animais de Doenças , Feminino , Imuno-Histoquímica , Radioisótopos de Índio/administração & dosagem , Radioisótopos de Índio/química , Radioisótopos de Índio/metabolismo , Injeções Intravenosas , Camundongos , Camundongos Endogâmicos NOD , Ácido Pentético/administração & dosagem , Ácido Pentético/química , Ácido Pentético/metabolismo , Peptídeos/administração & dosagem , Peptídeos/química , Compostos Radiofarmacêuticos/metabolismo , Distribuição TecidualRESUMO
SCOPE: Aspalathin, the main polyphenolic phytochemical of rooibos (Aspalathus linearis), has been attributed with health promoting properties, including a glucose lowering effect that can prove interesting for application as nutraceutical or therapeutic in (pre-)diabetics. Preservation of ß cell mass in the pancreas is considered a key issue for diabetes prevention or treatment, therefore the aim is to investigate whether aspalathin also has ß cell cytoprotective potential. METHODS AND RESULTS: Rat pancreatic islets and the ß cell line Insulinoma 1E (INS1E) are studied in vitro after exposure to various cytotoxic agents, namely streptozotocin (STZ), hydrogen peroxide, or chronic high glucose. The effect of aspalathin on cell survival and apoptosis is studied. Expression of relevant cytoprotective genes is analyzed by qRT-PCR and proteins by Western blot. Aspalathin is found to protect ß cells against cytotoxicity and apoptosis. This is associated with increased translocation of nuclear factor erythroid 2-related factor 2 (NRF2) and expression of its antioxidant target genes heme oxygenase 1 (Hmox1), NAD(P)H quinone dehydrogenase 1 (Nqo-1), and superoxide dismutase 1 (Sod1). CONCLUSION: It is proposed that aspalathin protects ß cells against glucotoxicity and oxidative stress by increasing the expression of NRF2-regulated antioxidant enzymes. This indicates that aspalathin is an interesting ß cell cytoprotectant.
Assuntos
Chalconas/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Células Cultivadas , Chalconas/administração & dosagem , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/toxicidade , Heme Oxigenase (Desciclizante)/genética , Peróxido de Hidrogênio/toxicidade , Masculino , Estresse Oxidativo/genética , Ratos Wistar , Estreptozocina/toxicidadeRESUMO
The insulin-like growth factor IGF-I is an important fetal and postnatal growth factor, which is also involved in tissue homeostasis via regulation of proliferation, differentiation, and cell survival. To understand the role of IGF-I in the pathophysiology of a variety of disorders, including growth disorders, cancer, and neurodegenerative diseases, a detailed knowledge of IGF-I signal transduction is required. This knowledge may also contribute to the development of new therapies directed at the IGF-I receptor or other signaling molecules. In this review, we will address IGF-I receptor signaling through the JAK/STAT pathway in IGF-I signaling and the role of cytokine-induced inhibitors of signaling (CIS) and suppressors of cytokine signaling (SOCS). It appears that, in addition to the canonical IGF-I signaling pathways through extracellular-regulated kinase (ERK) and phosphatidylinositol-3 kinase (PI3K)-Akt, IGF-I also signals through the JAK/STAT pathway. Activation of this pathway may lead to induction of SOCS molecules, well-known feedback inhibitors of the JAK/STAT pathway, which also suppress of IGF-I-induced JAK/STAT signaling. Furthermore, other IGF-I-induced signaling pathways may also be modulated by SOCS. It is conceivable that the effect of these classical inhibitors of cytokine signaling directly affect IGF-I receptor signaling, because they are able to associate to the intracellular part of the IGF-I receptor. These observations indicate that CIS and SOCS molecules are key to cross-talk between IGF-I receptor signaling and signaling through receptors belonging to the hematopoietic/cytokine receptor superfamily. Theoretically, dysregulation of CIS or SOCS may affect IGF-I-mediated effects on body growth, cell differentiation, proliferation, and cell survival.
Assuntos
Janus Quinases/metabolismo , Receptor IGF Tipo 1/metabolismo , Fatores de Transcrição STAT/metabolismo , Transdução de Sinais , Animais , Citocinas/metabolismo , Humanos , Modelos Biológicos , Proteínas Supressoras da Sinalização de Citocina/metabolismoRESUMO
OBJECTIVE: Since serum IGF-I levels are related to risks of prostate cancer and cytokines like interleukin (IL)-6 and IL-8 have been implicated in prostate cancer progression, we investigated the effects of IGF-I on IL-6 and IL-8 expression in the prostate cancer cell. DESIGN: In order to address the regulation by IGF-I of cytokine expression in prostate cancer cells we used cell cultures of established androgen dependent (LNCaP) and androgen-independent cell lines (DU-145 and PC-3). RESULTS: We found that IGF-I stimulates IL-8 mRNA expression and secretion in DU-145 cells, whereas the secretion of IL-6 was hardly affected. IGF-I enhances IL-8 expression in synergy with IL-1beta, but not with tumour necrosis factor (TNF)alpha. Similarly, on IL-8 promoter activity, IGF-I exerted synergistic effects with IL-1beta, but not with TNFalpha. Although IGF-I stimulated the phosphorylation of both Akt (protein kinase B) and extracellular-regulated kinase (ERK), the effect of IGF-I at IL-8 expression was inhibited only by U0126, a pharmacological inhibitor of MAPK/ERK kinase (MEK) and not by inhibition of the upstream activator of Akt, phosphatidylinositol-3 kinase (PI3K). CONCLUSIONS: Our results indicate that IGF-I stimulates IL-8 expression through the MEK-ERK pathway in DU-145 cells, at least in part, by augmentation of transcriptional activity. This finding is in accordance with our observations that IGF-I did not influence cytokine secretion and phosphorylation of ERK in LNCaP or PC-3 cells. It remains to be established whether IL-8 mediates certain effects of IGF-I on prostate cancer cells and whether differential responsiveness of prostate cancer cells to IGF-I relates to certain stages of prostate cancer.
Assuntos
Citocinas/farmacologia , Regulação Neoplásica da Expressão Gênica , Fator de Crescimento Insulin-Like I/farmacologia , Interleucina-8/genética , Neoplasias da Próstata/genética , Androstadienos/farmacologia , Butadienos/farmacologia , Linhagem Celular Tumoral , Inibidores Enzimáticos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Inflamação/fisiopatologia , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Masculino , Nitrilas/farmacologia , Reação em Cadeia da Polimerase , Regiões Promotoras Genéticas , Proteínas Recombinantes/farmacologia , Transfecção , WortmaninaRESUMO
To search for clues suggesting that beta cells may generate by transdifferentiation in humans, we assessed the presence of cells double positive for exocrine (amylase, carboxypeptidase A) and endocrine (insulin) markers in the pancreas of non-diabetic individuals (ND) and patients with type 2 diabetes (T2D). Samples from twelve ND and twelve matched T2D multiorgan donors were studied by electron microscopy, including amylase and insulin immunogold labeling; carboxypeptidase A immunofluorescence light microscopy assessment was also performed. In the pancreas from four T2D donors, cells containing both zymogen-like and insulin-like granules were observed, scattered in the exocrine compartment. Nature of granules was confirmed by immunogold labeling for amylase and insulin. Double positive cells ranged from 0.82 to 1.74 per mm2, corresponding to 0.26±0.045% of the counted exocrine cells. Intriguingly, cells of the innate immune systems (mast cells and/or macrophages) were adjacent to 33.3±13.6% of these hybrid cells. No cells showing co-localization of amylase and insulin were found in ND samples by electron microscopy. Similarly, cells containing both carboxypeptidase A and insulin were more frequently observed in the diabetic pancreata. These results demonstrate more abundant presence of cells containing both acinar markers and insulin in the pancreas of T2D subjects, which suggests possible conversion from one cellular type to the other and specific association with the diseased condition.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Insulina/metabolismo , Pâncreas Exócrino/metabolismo , Idoso , Biomarcadores/metabolismo , Diabetes Mellitus Tipo 2/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pâncreas Exócrino/ultraestruturaRESUMO
OBJECTIVE: Previous studies demonstrated that a phenylpropenoic acid glucoside (PPAG) from rooibos (Aspalathus linearis) extract had anti-hyperglycemic activity and significant protective effects on the pancreatic beta cell mass in a chronic diet-induced diabetes model. The present study evaluated the cytoprotective effect of the phytochemical on beta cells exposed to acute cell stress. METHODS: Synthetically prepared PPAG was administered orally in mice treated with a single dose of streptozotocin to acutely induce beta cell death and hyperglycemia. Its effect was assessed on beta cell mass, proliferation and apoptotic cell death. Its cytoprotective effect was also studied in vitro on INS-1E beta cells and on human pancreatic islet cells. RESULTS: Treatment with the phytochemical PPAG protected beta cells during the first days after the insult against apoptotic cell death, as evidenced by TUNEL staining, and prevented loss of expression of anti-apoptotic protein BCL2 in vivo. In vitro, PPAG protected INS-1E beta cells from streptozotocin-induced apoptosis and necrosis in a BCL2-dependent and independent way, respectively, depending on glucose concentration. PPAG also protected human pancreatic islet cells against the cytotoxic action of the fatty acid palmitate. CONCLUSIONS: These findings show the potential use of PPAG as phytomedicine which protects the beta cell mass exposed to acute diabetogenic stress.
Assuntos
Aspalathus/química , Diabetes Mellitus Experimental/tratamento farmacológico , Glucosídeos/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Fenilpropionatos/uso terapêutico , Extratos Vegetais/uso terapêutico , Substâncias Protetoras/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Animais , Apoptose/efeitos dos fármacos , Glicemia/análise , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/patologia , Glucosídeos/química , Glucosídeos/farmacologia , Humanos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/patologia , Masculino , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Fenilpropionatos/química , Fenilpropionatos/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Substâncias Protetoras/química , Substâncias Protetoras/farmacologiaRESUMO
Mutual communication between multiple myeloma (MM) cells and mesenchymal stromal cells (MSC) plays a pivotal role in supporting MM progression. In MM, MSC exhibit a different genomic profile and dysregulated cytokine secretion compared to normal MSC, however the mechanisms involved in these changes are not fully understood. Here, we examined the miRNA changes in human MSC after culture with conditioned medium of MM cells and found 19 dysregulated miRNAs, including upregulated miR-146a. Moreover, exosomes derived from MM cells contained miR-146a and could be transferred into MSC. After overexpressing miR-146a in MSC, secretion of several cytokines and chemokines including CXCL1, IL6, IL-8, IP-10, MCP-1, and CCL-5 was elevated, resulting in the enhancement of MM cell viability and migration. DAPT, an inhibitor of the endogenous Notch pathway, was able to abrogate the miR-146a-induced increase of cytokines in MSC, suggesting the involvement of the Notch pathway. Taken together, our results demonstrate a positive feedback loop between MM cells and MSC: MM cells promote the increase of miR146a in MSC which leads to more cytokine secretion, which in turn favors MM cell growth and migration.
Assuntos
Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , Mieloma Múltiplo/metabolismo , Comunicação Parácrina , Microambiente Tumoral , Linhagem Celular Tumoral , Movimento Celular , Sobrevivência Celular , Meios de Cultivo Condicionados/metabolismo , Citocinas/metabolismo , Exossomos/metabolismo , Perfilação da Expressão Gênica/métodos , Humanos , Células-Tronco Mesenquimais/patologia , MicroRNAs/genética , Mieloma Múltiplo/genética , Mieloma Múltiplo/patologia , Receptores Notch/metabolismo , Transdução de Sinais , Transfecção , Regulação para CimaRESUMO
The regenerative medicine field is expanding with great successes in laboratory and preclinical settings. Pancreatic acinar cells in diabetic mice were recently converted into ß-cells by treatment with ciliary neurotrophic factor (CNTF) and epidermal growth factor (EGF). This suggests that human acinar cells might become a cornerstone for diabetes cell therapy in the future, if they can also be converted into glucose-responsive insulin-producing cells. Presently, studying pancreatic acinar cell biology in vitro is limited by their high plasticity, as they rapidly lose their phenotype and spontaneously transdifferentiate to a duct-like phenotype in culture. We questioned whether human pancreatic acinar cell phenotype could be preserved in vitro by physico-chemical manipulations and whether this could be valuable in the study of ß-cell neogenesis. We found that culture at low temperature (4°C) resulted in the maintenance of morphological and molecular acinar cell characteristics. Specifically, chilled acinar cells did not form the spherical clusters observed in controls (culture at 37°C), and they maintained high levels of acinar-specific transcripts and proteins. Five-day chilled acinar cells still transdifferentiated into duct-like cells upon transfer to 37°C. Moreover, adenoviral-mediated gene transfer evidenced an active Amylase promoter in the 7-day chilled acinar cells, and transduction performed in chilled conditions improved acinar cell labelling. Together, our findings indicate the maintenance of human pancreatic acinar cell phenotype at low temperature and the possibility to efficiently label acinar cells, which opens new perspectives for the study of human acinar-to-ß-cell transdifferentiation.
Assuntos
Linhagem da Célula , Células Secretoras de Insulina/citologia , Pâncreas Exócrino/citologia , Amilases/genética , Animais , Técnicas de Cultura de Células , Diferenciação Celular , Transdiferenciação Celular , Células Cultivadas , Temperatura Baixa , Humanos , Células Secretoras de Insulina/metabolismo , Camundongos , Pâncreas Exócrino/metabolismo , Fenótipo , Regiões Promotoras Genéticas , TranscriptomaRESUMO
One week of treatment with EGF and gastrin (EGF/G) was shown to restore normoglycemia and to induce islet regeneration in mice treated with the diabetogenic agent alloxan. The mechanisms underlying this regeneration are not fully understood. We performed genetic lineage tracing experiments to evaluate the contribution of beta cell neogenesis in this model. One day after alloxan administration, mice received EGF/G treatment for one week. The treatment could not prevent the initial alloxan-induced beta cell mass destruction, however it did reverse glycemia to control levels within one day, suggesting improved peripheral glucose uptake. In vitro experiments with C2C12 cell line showed that EGF could stimulate glucose uptake with an efficacy comparable to that of insulin. Subsequently, EGF/G treatment stimulated a 3-fold increase in beta cell mass, which was partially driven by neogenesis and beta cell proliferation as assessed by beta cell lineage tracing and BrdU-labeling experiments, respectively. Acinar cell lineage tracing failed to show an important contribution of acinar cells to the newly formed beta cells. No appearance of transitional cells co-expressing insulin and glucagon, a hallmark for alpha-to-beta cell conversion, was found, suggesting that alpha cells did not significantly contribute to the regeneration. An important fraction of the beta cells significantly lost insulin positivity after alloxan administration, which was restored to normal after one week of EGF/G treatment. Alloxan-only mice showed more pronounced beta cell neogenesis and proliferation, even though beta cell mass remained significantly depleted, suggesting ongoing beta cell death in that group. After one week, macrophage infiltration was significantly reduced in EGF/G-treated group compared to the alloxan-only group. Our results suggest that EGF/G-induced beta cell regeneration in alloxan-diabetic mice is driven by beta cell neogenesis, proliferation and recovery of insulin. The glucose-lowering effect of the treatment might play an important role in the regeneration process.
Assuntos
Diabetes Mellitus Experimental/patologia , Fator de Crescimento Epidérmico/farmacologia , Gastrinas/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/patologia , Animais , Transporte Biológico/efeitos dos fármacos , Glicemia/metabolismo , Contagem de Células , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/metabolismo , Interações Medicamentosas , Regulação da Expressão Gênica/efeitos dos fármacos , Insulina/metabolismo , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Músculos/efeitos dos fármacos , Músculos/metabolismo , Fatores de TempoRESUMO
SCOPE: A major goal of diabetes therapy is to identify novel drugs that preserve or expand pancreatic beta cell mass. Here, we examined the effect of a phenylpropenoic acid glucoside (PPAG) on the beta cell mass, and via which mechanism this effect is established. METHODS AND RESULTS: Mice were fed a high-fat and fructose-containing diet to induce obesity and hyperglycemia. PPAG treatment protected obese mice from diet-induced hyperglycemia and resulted in a tripling of beta cell mass. The effect of the phytochemical on beta cell mass was neither due to increased proliferation, as determined by Ki67 immunostaining, nor to neogenesis, which was assessed by genetic lineage tracing. TUNEL staining revealed suppressed apoptosis in PPAG-treated obese mice. In vitro, PPAG protected beta cells from palmitate-induced apoptosis. It protected beta cells against ER stress by increasing expression of antiapoptotic B-cell lymphoma 2 (BCL2) protein without affecting proapoptotic signals. CONCLUSIONS: We identified an antidiabetic phytochemical that protects pancreatic beta cells from ER stress and apoptosis induced by high-fat diet/lipotoxicity. At the tissue level, this led to a tripling of beta cell mass. At the molecular level, the protective effect of the phytochemical was mediated by increasing BCL2 expression in beta cells.
Assuntos
Apoptose/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Glucosídeos/uso terapêutico , Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Lipotrópicos/uso terapêutico , Fenilpropionatos/uso terapêutico , Animais , Linhagem Celular Tumoral , Tamanho Celular/efeitos dos fármacos , Células Cultivadas , Cruzamentos Genéticos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica/efeitos adversos , Frutose/efeitos adversos , Glucosídeos/farmacologia , Hipoglicemiantes/farmacologia , Resistência à Insulina , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Lipotrópicos/farmacologia , Masculino , Camundongos Transgênicos , Obesidade/complicações , Obesidade/etiologia , Fenilpropionatos/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/agonistas , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Interferência de RNA , Ratos Wistar , Regulação para Cima/efeitos dos fármacosRESUMO
OBJECTIVE: Several studies showed that high serum levels of insulin-like growth factor-I (IGF-I) correlate with an increased risk for prostate cancer, although the causal role of IGF-I remains to be established. In this study, we addressed the role of IGF-I as a serum factor on the growth of two androgen-independent cell lines (Du145 and PC3) and one androgen-dependent cell line (LNCaP). DESIGN: We investigated the effects of a blocking antibody against the IGF-I receptor (αIR3) on DNA synthesis in prostate cancer cells cultured in the presence of recombinant human IGF-I or normal human serum (NHS). RESULTS: We show that in all three prostate cancer cell lines, NHS exerts a markedly stronger stimulating effect on DNA synthesis than IGF-I, and that the effect of NHS can be completely abrogated by an antibody against the IGF-I receptor (αIR3). Using pharmacological inhibitors of the two canonical IGF-I receptor signaling pathways, we show that the phosphatidylinositol-3'-kinase (PI3K) and the Mek-Erk pathways are not required for the stimulating effect of NHS. CONCLUSION: Our observations indicate that the stimulating effect of NHS is completely dependent on IGF-I receptor signaling transduction and that IGF-I stimulates DNA synthesis in prostate cancer cells in strong synergy with other serum factors. We speculate that the role of other serum factors could explain the discrepancy between the results observed in different animal models to study the function of IGF-I in prostate cancer.
Assuntos
Fator de Crescimento Insulin-Like I/metabolismo , Neoplasias da Próstata , Receptor IGF Tipo 1/antagonistas & inibidores , Soro/metabolismo , Transdução de Sinais , Anticorpos Bloqueadores/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Fator de Crescimento Insulin-Like I/farmacologia , Masculino , Neoplasias da Próstata/patologia , Inibidores de Proteínas Quinases/farmacologiaRESUMO
Apoptosis of human neutrophils is a crucial mechanism for the resolution of inflammation. We previously showed that insulin-like growth factor-1 (IGF1) delays spontaneous neutrophil apoptosis without influencing the secretion of cytokines by these cells. In the present study, we further addressed the role of IGF1 in regulating neutrophil survival in the presence of other factors present during inflammation, and the mechanism involved in delaying apoptosis. We show that IGF1 delays neutrophil apoptosis triggered by the agonistic anti-Fas antibody CH11 and that the effect of IGF1 is comparable in magnitude to that of the acknowledged anti-apoptotic cytokines interferon-gamma (IFNG) and granulocyte-macrophage colony-stimulating factor (GM-CSF; now known as CSF2). Furthermore, IGF1 exerted additional effects on cell survival in the presence of these cytokines. IGF1 did not affect Fas expression or activation by anti-Fas of caspase-8, but inhibited the depolarization of the mitochondrial membrane. Inhibitor studies indicate that the phosphatidylinositol-3 kinase (PI3K) pathway, but not the MEK-ERK pathway, mediates the effects of IGF1. However, in contrast to CSF2, IGF1 did not induce phosphorylation and translocation to the membrane of AKT, the canonical downstream target of PI3K. We therefore speculate that other downstream targets of PI3K are involved in the delay of neutrophil apoptosis by IGF1, possibly through stabilization of the mitochondrial membrane.