An anti-CD19 antibody coupled to a tetanus toxin peptide induces efficient Fas ligand (FasL)-mediated cytotoxicity of a transformed human B cell line by specific CD4+ T cells.

Treatment of B cell lymphoma patients with MoAbs specific for the common B cell marker (CD20) has shown a good overall response rate, but the number of complete remissions is still very low. The use of MoAbs coupled to radioisotopes can improve the results, but induces undesirable myelodepression. As an alternative, we proposed to combine the specificity of MoAbs with the immunogenicity of T cell epitopes. We have previously shown that an anti-Ig lambda MoAb coupled to an MHC class II-restricted universal T cell epitope peptide P2 derived from tetanus toxin induces efficient lysis of a human B cell lymphoma by a specific CD4+ T cell line. Here we demonstrate that the antigen presentation properties of the MoAb peptide conjugate are maintained using a MoAb directed against a common B cell marker, CD19, which is known to be co-internalized with the B cell immunoglobulin receptor. In addition, we provide evidence that B cell lysis is mediated by the Fas apoptosis pathway, since Fas (CD95), but not tumour necrosis factor receptor (TNFr) or TNF-related receptors, is expressed by the target B cells, and FasL, but not perforin, is expressed by the effector T cells. These results show that B cell lymphomas can be 'foreignized' by MoAb-peptide P2 conjugates directed against the common B cell marker CD19 and eliminated by peptide P2-specific CD4+ T cells, via the ubiquitous Fas receptor. This approach, which bridges the specificity of passive antibody therapy with an active T cell immune response, may be complementary to and more efficient than the present therapy results with unconjugated chimeric anti-CD20 MoAbs.

Effects of mineralocorticoid and K+ concentration on K+ secretion and ROMK channel expression in a mouse cortical collecting duct cell line.

The cortical collecting duct (CCD) plays a key role in regulated K(+) secretion, which is mediated mainly through renal outer medullary K(+) (ROMK) channels located in the apical membrane. However, the mechanisms of the regulation of urinary K(+) excretion with regard to K(+) balance are not well known. We took advantage of a recently established mouse CCD cell line (mCCD(cl1)) to investigate the regulation of K(+) secretion by mineralocorticoid and K(+) concentration. We show that this cell line expresses ROMK mRNA and a barium-sensitive K(+) conductance in its apical membrane. As this conductance is sensitive to tertiapin-Q, with an apparent affinity of 6 nM, and to intracellular acidification, it is probably mediated by ROMK. Overnight exposure to 100 nM aldosterone did not significantly change the K(+) conductance, while it increased the amiloride-sensitive Na(+) transport. Overnight exposure to a high K(+) (7 mM) concentration produced a small but significant increase in the apical membrane barium-sensitive K(+) conductance. The mRNA levels of all ROMK isoforms measured by qRT-PCR were not changed by altering the basolateral K(+) concentration but were decreased by 15-45% upon treatment with aldosterone (0.3 or 300 nM for 1 and 3 h). The paradoxical response of ROMK expression to aldosterone could possibly work as a preventative mechanism to avoid excessive K(+) loss which would otherwise result from the increased electrogenic Na(+) transport and associated depolarization of the apical membrane in the CCD. In conclusion, mCCD(cl1) cells demonstrate a significant K(+) secretion, probably mediated by ROMK, which is not stimulated by aldosterone but increased by overnight exposure to a high K(+) concentration.

Encapsulation of packaging cell line results in successful retroviral-mediated transfer of a suicide gene in vivo in an experimental model of glioblastoma.

AIMS: Retroviral-mediated gene therapy has been proposed as a primary or adjuvant treatment for advanced cancer, because retroviruses selectively infect dividing cells. Efficacy of retroviral-mediated gene transfer, however, is limited in vivo. Although packaging cell lines can produce viral vectors continuously, such allo- or xenogeneic cells are normally rejected when used in vivo. Encapsulation using microporous membranes can protect the packaging cells from rejection. In this study, we used an encapsulated murine packaging cell line to test the effects of in situ delivery of a retrovirus bearing the herpes simplex virus thymidine kinase suicide gene in a rat model of orthotopic glioblastoma. MATERIALS AND METHODS: To test gene transfer in vitro, encapsulated murine psi2-VIK packaging cells were co-cultured with baby hamster kidney (BHK) cells, and the percentage of transfected BHK cells was determined. For in vivo experiments, orthotopic C6 glioblastomas were established in Wistar rats. Capsules containing psi2-VIK cells were stereotaxically implanted into these tumours and the animals were treated with ganciclovir (GCV). Tumours were harvested 14 days after initiation of GCV therapy for morphometric analysis. RESULTS: Encapsulation of psi2-VIK cells increased transfection rates of BHK target cells significantly in vitro compared to psi2-VIK conditioned medium (3 x 10(6) vs 2.3 x 10(4) cells; P<0.001). In vivo treatment with encapsulated packaging cells resulted in 3% to 5% of C6 tumour cells transduced and 45% of tumour volume replaced by necrosis after GCV (P<0.01 compared to controls). CONCLUSION: In this experimental model of glioblastoma, encapsulation of a xenogeneic packaging cell line increased half-life and transduction efficacy of retrovirus-mediated gene transfer and caused significant tumour necrosis.

The overexpression of SOX2 affects the migration of human teratocarcinoma cell line NT2/D1.

The altered expression of the SOX2 transcription factor is associated with oncogenic or tumor suppressor functions in human cancers. This factor regulates the migration and invasion of different cancer cells. In this study we investigated the effect of constitutive SOX2 overexpression on the migration and adhesion capacity of embryonal teratocarcinoma NT2/D1 cells derived from a metastasis of a human testicular germ cell tumor. We detected that increased SOX2 expression changed the speed, mode and path of cell migration, but not the adhesion ability of NT2/D1 cells. Additionally, we demonstrated that SOX2 overexpression increased the expression of the tumor suppressor protein p53 and the HDM2 oncogene. Our results contribute to the better understanding of the effect of SOX2 on the behavior of tumor cells originating from a human testicular germ cell tumor. Considering that NT2/D1 cells resemble cancer stem cells in many features, our results could contribute to the elucidation of the role of SOX2 in cancer stem cells behavior and the process of metastasis.

The human estrogen receptor can regulate exogenous but not endogenous vitellogenin gene promoters in a Xenopus cell line.

Transfection of a human estrogen receptor cDNA expression vector (HEO) into cultured Xenopus kidney cells confers estrogen responsiveness to the recipient cells as demonstrated by the hormone dependent expression of co-transfected Xenopus vitellogenin-CAT chimeric genes. The estrogen stimulation of these vit-CAT genes is dependent upon the presence of the vitellogenin estrogen responsive element (ERE) in their 5' flanking region. Thus, functional human estrogen receptor (hER) can be synthesized in heterologous lower vertebrate cells and can act as a trans-acting regulatory factor that is necessary, together with estradiol, for the induction of the vit-CAT constructs in these cells. In addition, vitellogenin minigenes co-transfected with the HEO expression vector also respond to hormonal stimulation. Their induction is not higher than that of the vit-CAT chimeric genes. It suggests that in the Xenopus kidney cell line B 3.2, the structural parts of the vitellogenin minigenes do not play a role in the induction process. Furthermore, no stabilizing effect of estrogen on vitellogenin mRNA is observed in these cells. In contrast to the transfected genes, the endogenous chromosomal vitellogenin genes remain silent, demonstrating that in spite of the presence of the hER and the hormone, the conditions necessary for their activation are not fulfilled.

Breast cancer and melanoma cell line identification by FTIR imaging after formalin-fixation and paraffin-embedding.

Over the past few decades, Fourier transform infrared (FTIR) spectroscopy coupled to microscopy has been recognized as an emerging and potentially powerful tool in cancer research and diagnosis. For this purpose, histological analyses performed by pathologists are mostly carried out on biopsied tissue that undergoes the formalin-fixation and paraffin-embedding (FFPE) procedure. This processing method ensures an optimal and permanent preservation of the samples, making FFPE-archived tissue an extremely valuable source for retrospective studies. Nevertheless, as highlighted by previous studies, this fixation procedure significantly changes the principal constituents of cells, resulting in important effects on their infrared (IR) spectrum. Despite the chemical and spectral influence of FFPE processing, some studies demonstrate that FTIR imaging allows precise identification of the different cell types present in biopsied tissue, indicating that the FFPE process preserves spectral differences between distinct cell types. In this study, we investigated whether this is also the case for closely related cell lines. We analyzed spectra from 8 cancerous epithelial cell lines: 4 breast cancer cell lines and 4 melanoma cell lines. For each cell line, we harvested cells at subconfluence and divided them into two sets. We first tested the "original" capability of FTIR imaging to identify these closely related cell lines on cells just dried on BaF2 slides. We then repeated the test after submitting the cells to the FFPE procedure. Our results show that the IR spectra of FFPE processed cancerous cell lines undergo small but significant changes due to the treatment. The spectral modifications were interpreted as a potential decrease in the phospholipid content and protein denaturation, in line with the scientific literature on the topic. Nevertheless, unsupervised analyses showed that spectral proximities and distances between closely related cell lines were mostly, but not entirely, conserved after FFPE processing. Finally, PLS-DA statistical analyses highlighted that closely related cell lines are still successfully identified and efficiently distinguished by FTIR spectroscopy after FFPE treatment. This last result paves the way towards identification and characterization of cellular subtypes on FFPE tissue sections by FTIR imaging, indicating that this analysis technique could become a potential useful tool in cancer research.

Glucagon-like peptide-1-(7-36) amide, oxyntomodulin, and glucagon interact with a common receptor in a somatostatin-secreting cell line.

Glucagon-like peptide-1(7-36)amide (tGLP-1), oxyntomodulin (OXM), and glucagon are posttranslational end products of the glucagon gene expressed in intestinal L-cells. In vivo, these peptides are potent inhibitors of gastric acid secretion via several pathways, including stimulation of somatostatin release. We have examined the receptors through which these peptides stimulate somatostatin secretion using the somatostatin-secreting cell line RIN T3. tGLP-1, OXM, and glucagon stimulated somatostatin release and cAMP accumulation in RIN T3 cells to similar maximum levels, with ED50 values close to 0.2, 2, and 50 nM and 0.02, 0.3, and 8 nM, respectively. Binding of [125I]tGLP-1, [125I]OXM, and [125I]glucagon to RIN T3 plasma membranes was inhibited by the three peptides, with relative potencies as follows: tGLP-1 &gt; OXM &gt; glucagon. Whatever the tracer used, the IC50 for tGLP-1 was close to 0.15 nM and was shifted rightward for OXM and glucagon by about 1 and 2-3 orders of magnitude, respectively. Scatchard analyses for the three peptides were compatible with a single class of receptor sites displaying a similar maximal binding close to 2 pmol/mg protein. In the hamster lung fibroblast cell line CCL39 transfected with the receptor for tGLP-1, binding of [125I]tGLP-1 was inhibited by tGLP-1, OXM, and glucagon, with relative potencies close to those obtained with RIN T3 membranes. Chemical cross-linking of [125I]tGLP-1, [125I]OXM, and [125I]glucagon revealed a single band at 63,000 mol wt, the intensity of which was dose-dependently reduced by all three peptides. These data suggest that in the somatostatin-secreting cell line RIN T3, OXM and glucagon stimulate somatostatin release through a tGLP-1-preferring receptor. This suggests that some biological effects, previously described for these peptides, might be due to their interaction with this receptor.

IL-17F co-expression improves cell growth characteristics and enhances recombinant protein production during CHO cell line engineering.

The generation of a high productivity cell line is a critical step in the production of a therapeutic protein. Many innovative engineering strategies have been devised in order to maximize the expression rate of production cells for increased process efficiency. Less effort has focused on improvements to the cell line generation process, which is typically long and laborious when using mammalian cells. Based on unexpected findings when generating stable CHO cell lines expressing human IL-17F, we studied the benefit of expressing this protein during the establishment of production cell lines. We demonstrate that IL-17F expression enhances the rate of selection and overall number of selected cell lines as well as their transgene expression levels. We also show that this benefit is observed with different parental CHO cell lines and selection systems. Furthermore, IL-17F expression improves the efficiency of cell line subcloning processes. IL-17F can therefore be exploited in a standard manufacturing process to obtain higher productivity clones in a reduced time frame.

Transplantation of a human mammary carcinoma cell line (BT 20) into nude mice.

Cell suspensions of a human mammary carcinoma cellline (BT 20), wh en injected subcutaneously into nude athymie mice (BALB/c NujNu), produced tumor nodules at the injection site. Subsequent seriai transM plantations also gave rise to neoplastic nodules after latency periods averaging 3 weeks. The nodules displayed morphologie and functional characteristics comparable to those of the original tumor cells. Metastases, however, were not observed in any of the tumor-bearing mice.

HDLs protect the MIN6 insulinoma cell line against tunicamycin-induced apoptosis without inhibiting ER stress and without restoring ER functionality.

HDLs protect pancreatic beta cells against apoptosis induced by several endoplasmic reticulum (ER) stressors, including thapsigargin, cyclopiazonic acid, palmitate and insulin over-expression. This protection is mediated by the capacity of HDLs to maintain proper ER morphology and ER functions such as protein folding and trafficking. Here, we identified a distinct mode of protection exerted by HDLs in beta cells challenged with tunicamycin (TM), a protein glycosylation inhibitor inducing ER stress. HDLs were found to inhibit apoptosis induced by TM in the MIN6 insulinoma cell line and this correlated with the maintenance of a normal ER morphology. Surprisingly however, this protective response was neither associated with a significant ER stress reduction, nor with restoration of protein folding and trafficking in the ER. These data indicate that HDLs can use at least two mechanisms to protect beta cells against ER stressors. One that relies on the maintenance of ER function and one that operates independently of ER function modulation. The capacity of HDLs to activate several anti-apoptotic pathways in beta cells may explain their ability to efficiently protect these cells against a variety of insults.

Neuropeptide Y expression and regulation in a differentiated rat insulin-secreting cell line.

Neuropeptide-Y (NPY) is a 36-amino acid peptide known to inhibit glucose-stimulated insulin secretion in various animal models in vitro and in vivo. NPY is thought to be one of the mediators of sympathetic action in the pancreas through nerve endings surrounding the islets, and it has recently been shown to be synthesized within the islets of Langerhans. To elucidate the potential role of NPY in the endocrine pancreas, we studied the expression and regulation of NPY secretion in a rat insulinoma cell line (INS-1). NPY mRNA and peptide are highly expressed and secreted by INS-1 cells. NPY levels were determined by a sensitive and specific two-site amplified enzyme-linked immunosorbent assay. Incubation of INS-1 cells with various glucose concentrations did not modify NPY secretion; however, stimulation of adenylate cyclase by forskolin induced a dose- and time-dependent increase in NPY release in the medium. The glucagon-like peptide-I-(7-36) amide (GLP-1), a known gluco-incretin in humans, induced at low concentration (10(-9) M) a similar expression of NPY mRNA and peptide secretion in INS-1 cells. On the other hand, the inhibition of cAMP accumulation by the alpha 2-adrenergic agonist clonidine decreased NPY secretion. In conclusion, 1) high levels of gene expression and secretion of NPY are found in a rat insulinoma cell line (INS-1). 2) Accumulation of cAMP induced by forskolin or a gluco-incretin (GLP-1) induces a further increase in NPY gene expression and release. 3) NPY secretion is not modulated by low or high glucose concentrations in the medium. 4) Induction of NPY, a known inhibitor of insulin secretion, may represent a novel counterregulatory mechanism of insulin secretion, limiting the stimulatory effect of GLP-1 on insulin secretion.

Regulation of sodium transport in the cortical collecting duct : physiological role of GILZ in vitro and in vivo : characterisation of Na+ transport in the mCCDcl1 cell line

SUMMARY Regulation of sodium excretion by the kidney is a key mechanism in the long term regulation of blood pressure, and when altered it constitutes a risk factor for the appearance of arterial hypertension. Aldosterone, which secretion depends upon salt intake in the diet, is a steroid hormone that regulates sodium reabsorption in the distal part of the nephron (functional unit of the kidney) by modulating gene transcription. It has been shown that it can act synergistically with the peptidic hormone insulin through the interaction of their signalisation pathways. Our work consisted of two distinct parts: 1) the in vitro and in vivo characterisation of Glucocorticoid-Induced Leucine Zipper (GILZ) (an aldosterone-induced gene) mechanism of action; 2) the in vitro characterisation of insulin mechanism of action and its interaction with aldosterone. GILZ mRNA, coded by the TSC22D3 gene, is strongly induced by aldosterone in the cell line of principal cells of the cortical collecting duct (CCD) mpkCCDc14, suggesting that GILZ is a mediator of aldosterone response. Co-expression of GILZ and the amiloride-sensitive epithelial sodium channel ENaC in vitro in the Xenopus oocyte expression system showed that GILZ has no direct effect on the ENaC-mediated Na+ current in basal conditions. To define the role of GILZ in the kidney and in other organs (colon, heart, skin, etc.), a conditional knock-out mouse is being produced and will allow the in vivo study of its role. Previous data showed that insulin induced a transepithelial sodium transport at supraphysiological concentrations. Insulin and the insulin-like growth factor 1 (IGF-1) are able to bind to each other receptor with an affinity 50 to 100 times lower than to their cognate receptor. Our starting hypothesis was that the insulin effect observed at these supraphysiological concentrations is actually mediated by the IGF receptor type 1 (IGF-1R). In a new cell line that presents all the characteristics of the principal cells of the CCD (mCCDc11) we have shown that both insulin and IGF-1 induce a physiologically significant increase of Na+ transport through the activation of IGF-1R. Aldosterone and insulin/IGF-1 have an additive effect on Na+ transport, through the activation of the PI3-kinase (PI3-K) pathway and the phosphorylation of the serum- and glucocorticoid-induced kinase 1 (Sgk1) by the IGF-1R, and the induction of Sgk1 expression by aldosterone. Thus, Sgk1 integrates IGF-1/insulin and aldosterone effects. We suggest that IGF-1 is physiologically relevant in the modulation of sodium balance, while insulin can only regulate Na+ transport at supraphysiological conditions. Both hormones would bind to the IGF-1R and induce Na+ transport by activating the PI3-K PDK1/2 - Sgk1 pathway. We have shown for the first time that Sgk1 is expressed and phosphorylated in principal cells of the CCD in basal conditions, although the mechanism that maintains Sgk1 phosphorylation is not known. This new role for IGF-1 suggests that it could be a salt susceptibility gene. In effect, IGF-1 stimulates Na+ and water transport in the kidney in vivo. Moreover, 35 % of the acromegalic patients (overproduction of growth hormone and IGF-1) are hypertensives (higher proportion than in normal population), and genetic analysis suggest a link between the IGF-1 gene locus and blood pressure. RÉSUMÉ La régulation de l'excrétion rénale de sodium (Na+) joue un rôle principal dans le contrôle à long terme de la pression sanguine, et ses altérations constituent un facteur de risque de l'apparition d'une hypertension artérielle. L'aldosterone, dont la sécrétion dépend de l'apport en sel dans la diète, est une hormone stéroïdienne qui régule la réabsorption de Na+ dans la partie distale du nephron (unité fonctionnelle du rein) en contrôlant la transcription de gènes. Elle peut agir de façon synergistique avec l'hormone peptidique insuline, probablement via l'interaction de leurs voies de signalisation cellulaire. Le but de notre travail comportait deux volets: 1) caractériser in vitro et in vivo le mécanisme d'action du Glucocorticoid Induced Leucine Zipper (GILZ) (un gène induit par l'aldosterone); 2) caractériser in vitro le mécanisme d'action de l'insuline et son interaction avec l'aldosterone. L'ARNm de GILZ, codé par le gène TSC22D3, est induit par l'aldosterone dans la lignée cellulaire de cellules principales du tubule collecteur cortical (CCD) mpkCCDc14, suggérant que GILZ est un médiateur potentiel de la réponse à l'aldosterone. La co-expression in vitro de GILZ et du canal à Na+ sensible à l'amiloride ENaC dans le système d'expression de l'oocyte de Xénope a montré que GILZ n'a pas d'effet sur les courants sodiques véhiculées par ENaC en conditions basales. Une souris knock-out conditionnelle de GILZ est en train d'être produite et permettra l'étude in vivo de son rôle dans le rein et d'autres organes. Des expériences préliminaires ont montré que l'insuline induit un transport transépithelial de Na+ à des concentrations supraphysiologiques. L'insuline et l'insulin-like growth factor 1 (IGF-1) peuvent se lier à leurs récepteurs réciproques avec une affinité 50 à 100 fois moindre qu'à leur propre récepteur. Nous avons donc proposé que l'effet de l'insuline soit médié par le récepteur à l'IGF type 1 (IGF-1R). Dans une nouvelle lignée cellulaire qui présente toutes les caractéristiques des cellules principales du CCD (mCCDc11) nous avons montré que les deux hormones induisent une augmentation physiologiquement significative du transport du Na+ par l'activation des IGF-1 R. Aldosterone et insuline/IGF-1 ont un effet additif sur le transport de Na+, via l'activation de la voie de la PI3-kinase et la phosphorylation de la serum- and glucocorticoid-induced kinase 1 (Sgk1) par l'IGF-1R, dont l'expression est induite par l'aldosterone. Sgk1 intègre les effets de l'insuline et l'aldosterone. Nous proposons que l'IGF-1 joue un rôle dans la modulation physiologique de la balance sodique, tandis que l'insuline régule le transport de Na+ à des concentrations supraphysiologiques. Les deux hormones agissent en se liant à l'IGF-1R et induisent le transport de Na+ en activant la cascade de signalisation PI3-K - PDK1/2 - Sgk1. Nous avons montré pour la première fois que Sgk1 est exprimée et phosphorylée dans des conditions basales dans les cellules principales du CCD, mais le mécanisme qui maintient sa phosphorylation n'est pas connu. Ce nouveau rôle pour l'IGF-1 suggère qu'il pourrait être un gène impliqué de susceptibilité au sel. Aussi, l'IGF-1 stimule le transport rénal de Na+ in vivo. De plus, 35 % des patients atteints d'acromégalie (surproduction d'hormone de croissance et d'IGF-1) sont hypertensifs (prévalence plus élevée que la population normale), et des analyses génétiques suggèrent un lien entre le locus du gène de l'IGF-1 et la pression sanguine. RÉSUMÉ GRAND PUBLIC Nos ancêtres se sont génétiquement adaptés pendant des centaines de millénaires à un environnement pauvre en sel (chlorure de sodium) dans la savane équatoriale, où ils consommaient moins de 0,1 gramme de sel par jour. On a commencé à ajouter du sel aux aliments avec l'apparition de l'agriculture (il y a 5000 à 10000 années), et aujourd'hui une diète omnivore, qui inclut des plats préparés, contient plusieurs fois la quantité de sodium nécessaire pour notre fonction physiologique normale (environ 10 grammes par jour). Le corps garde sa concentration constante dans le sang en s'adaptant à une consommation très variable de sel. Pour ceci, il module son excrétion soit directement, soit en sécrétant des hormones régulatrices. Le rein joue un rôle principal dans cette régulation puisque l'excrétion urinaire de sel change selon la diète et peut aller d'une quantité dérisoire à plus de 36 grammes par jour. L'attention qu'on prête au sel est liée à sa relation avec l'hypertension essentielle. Ainsi, le contrôle rénal de l'excrétion de sodium et d'eau est le principal mécanisme dans la régulation de la pression sanguine, et une ingestion excessive de sel pourrait être l'un des facteurs-clé déclenchant l'apparition d'un phénotype hypertensif. L'hormone aldosterone diminue l'excrétion de sodium par le rein en modulant l'expression de gènes qui pourraient être impliqués dans la sensibilité au sel. Dans une lignée cellulaire de rein l'expression du gène TSC22D3, qui se traduit en la protéine Glucocorticoid Induced Leucine Zipper (GILZ), est fortement induite par l'aldosterone. Ceci suggère que GILZ est un médiateur potentiel de l'effet de l'aldosterone, et pourrait être impliqué dans la sensibilité au sel. Pour analyser la fonction de GILZ dans le rein plusieurs approches ont été utilisées. Par exemple, une souris dans laquelle GILZ est spécifiquement inactivé dans le rein est en train d'être produite et permettra l'étude du rôle de GILZ dans l'organisme. De plus, on a montré que GILZ, en conditions basales, n'a pas d'effet direct sur la protéine transportant le sodium à travers la membrane des cellules, le canal sodique épithélial ENaC. On a aussi essayé de trouver des protéines qui interagissent directement avec GILZ utilisant une technique appelée du « double-hybride dans la levure », mais aucun candidat n'a émergé. Des études ont montré que, à de hautes concentrations, l'insuline peut aussi diminuer l'excrétion de sodium. A ces concentrations, elle peut activer son récepteur spécifique, mais aussi le récepteur d'une autre hormone, l'Insulin-Like Growth Factor 1 (IGF-1). En plus, l'infusion d'IGF-1 augmente la rétention rénale de sodium et d'eau, et des mutations du gène codant pour l'IGF-1 sont liées aux différents niveaux de pression sanguine. On a utilisé une nouvelle lignée cellulaire de rein développée dans notre laboratoire, appelée mCCDc11, pour analyser l'importance relative des deux hormones dans l'induction du transport de sodium. On a montré que les deux hormones induisent une augmentation significative du transport de sodium par l'activation de récepteurs à l'IGF-1 et non du récepteur à l'insuline. On a montré qu'à l'intérieur de la cellule leur activation induit une augmentation du transport sodique par le biais du canal ENaC en modifiant la quantité de phosphates fixés sur la protéine Serumand Glucocorticoid-induced Kinase 1 (Sgk1). On a finalement montré que l'IGF-1 et l'aldosterone ont un effet additif sur le transport de sodium en agissant toutes les deux sur Sgk1, qui intègre leurs effets dans le contrôle du transport de sodium dans le rein.