The role of growth differentiaton factor 15 in diabetic kidney injury

De data gepresenteerd in dit proefschrift demonstreren een grote rol voor GDF15 in de ontwikkeling van diabetische nefropathie. GDF15 expressie was sterk geïnduceerd in de glomerulus na inductie van diabetes bij ratten en muizen. Verder toonde onze studie in GDF15 knockout en wild type muizen aan dat GDF15 tubulaire functie in stand houdt en interstitiële schade voorkomt in zowel type 1 en type 2 diabetes. Echter, GDF15 beschermde de glomerulus niet tegen sclerose en beschermde niet tegen albuminurie. Bovendien tastte voorbehandeling van aorta’s met GDF15 de endotheelfunctie aan, met als gevolg een verstoorde vasculaire contractie en relaxatie. Ten slotte zijn plasmaspiegels van GDF15 gecorreleerd aan de progressie van albuminurie bij patiënten met T2DM. De vinding dat BMPR2 lijkt te zijn betrokken als één van de belangrijkste receptoren voor GDF15, kan de ontwikkeling van nieuwe therapeutische benaderingen voor het beperken van nierschade bij diabetespatiënten bespoedigen

The role of growth differentiaton factor 15 in diabetic kidney injury

De data gepresenteerd in dit proefschrift demonstreren een grote rol voor GDF15 in de ontwikkeling van diabetische nefropathie. GDF15 expressie was sterk geïnduceerd in de glomerulus na inductie van diabetes bij ratten en muizen. Verder toonde onze studie in GDF15 knockout en wild type muizen aan dat GDF15 tubulaire functie in stand houdt en interstitiële schade voorkomt in zowel type 1 en type 2 diabetes. Echter, GDF15 beschermde de glomerulus niet tegen sclerose en beschermde niet tegen albuminurie. Bovendien tastte voorbehandeling van aorta’s met GDF15 de endotheelfunctie aan, met als gevolg een verstoorde vasculaire contractie en relaxatie. Ten slotte zijn plasmaspiegels van GDF15 gecorreleerd aan de progressie van albuminurie bij patiënten met T2DM. De vinding dat BMPR2 lijkt te zijn betrokken als één van de belangrijkste receptoren voor GDF15, kan de ontwikkeling van nieuwe therapeutische benaderingen voor het beperken van nierschade bij diabetespatiënten bespoedigen. The studies presented in this thesis demonstrated a profound role for GDF15 in the development of diabetic nephropathy. GDF15 expression was strongly induced in the glomerulus after induction of diabetes in rats and mice. Further, our study in GDF15 knockout and wild type mice showed that GDF15 preserved tubular function and prevented interstitial damage in both type 1 and type 2 diabetes. However, GDF15 did not protect the glomerulus from sclerosis nor did it prevent albuminuria. Furthermore, pretreatment of vessels (aortas) with GDF15 affected endothelial function resulting in impaired vascular contraction and relaxation. Finally, plasma levels of GDF15 correlated with progression of albuminuria in patients with T2DM. The notion that BMPR2 seems to be involved as a main receptor for GDF15, may facilitate development of novel therapeutic approaches to limit renal damage in diabetic patients.

Troubleshooting methods for microarray gene expression analysis in the onset of diabetic kidney disease

<p>Introduction: Microarrays have become the standard technique for discovering new genes involved in the development of (kidney) disease. Diabetic nephropathy is a frequent complication of diabetes and is characterized by renal fibrosis. As the pathways leading to fibrosis are initiated early in diabetes and in the current study, we aimed at identifying genes associated with renal fibrosis in the first week after induction of diabetes in the rat streptozotocin (STZ) model. Methods: Conventional microarray analysis methods comparing gene expression to a common reference are not very suitable for time series as gene lists for all time point are very heterogeneous. We therefore sought an analysis technique that would allow us to easily find genes that we either substantially up or down regulated during the first week of diabetes. In the new method, the normalized expression of individual genes was plotted in time. Subsequently, the area under the curve (AUC) was calculated to quantify the overall level of changes in expression of individual genes. Results: AUCs for all genes were plotted in a histogram showing a normal distribution with a mean of close to 0, indicating no change in expression for the majority of genes. Genes with AUCs outside 3 standard deviations of the mean were considered significantly different from control. Discussion: Using this technique, a total of 290 genes were found to be significantly changed in the first week of diabetes. Data on a subset of genes were confirmed by real-time PCR, indicating the validity of the employed new analysis method. (C) 2013 Elsevier Inc. All rights reserved.</p>

Genetic deletion of growth differentiation factor 15 augments renal damage in both type 1 and type 2 models of diabetes

<p>Growth differentiation factor 15 (GDF15) is emerging as valuable biomarker in cardiovascular disease and diabetic kidney disease. Also, GDF15 represents an early response gene induced after tissue injury and studies performed in GDF15 knockout (KO) mice suggest that GDF15 plays a protective role after injury. In the current study, we investigated the role of GDF15 in the development of diabetic kidney damage in type 1 and type 2 models of diabetes. Renal damage was assessed in GDF15 KO mice and wild-type (WT) mice in streptozotocin type 1 and db/db type 2 diabetic models. Genetic deletion of GDF15 augmented tubular and interstitial damage in both models of diabetes, despite similar diabetic states in KO and WT mice. Increased tubular damage in KO animals was associated with increased glucosuria and polyuria in both type 1 and type 2 models of diabetes. In both models of diabetes, KO mice showed increased interstitial damage as indicated by increased alpha-smooth muscle actin staining and collagen type 1 expression. In contrast, glomerular damage was similarly elevated in diabetic KO and WT mice. In type 1 diabetes, GDF15 KO mice demonstrated increased expression of inflammatory markers. In type 2 diabetes, elevated levels of plasma creatinine indicated impaired kidney function in KO mice. GDF15 protects the renal interstitium and tubular compartment in experimental type 1 and 2 diabetes without affecting glomerular damage.</p>

Development of A Chimeric Antigen Receptor Targeting C-Type Lectin-Like Molecule-1 for Human Acute Myeloid Leukemia

The treatment of patients with acute myeloid leukemia (AML) with targeted immunotherapy is challenged by the heterogeneity of the disease and a lack of tumor-exclusive antigens. Conventional immunotherapy targets for AML such as CD33 and CD123 have been proposed as targets for chimeric antigen receptor (CAR)-engineered T-cells (CAR-T-cells), a therapy that has been highly successful in the treatment of B-cell leukemia and lymphoma. However, CD33 and CD123 are present on hematopoietic stem cells, and targeting with CAR-T-cells has the potential to elicit long-term myelosuppression. C-type lectin-like molecule-1 (CLL1 or CLEC12A) is a myeloid lineage antigen that is expressed by malignant cells in more than 90% of AML patients. CLL1 is not expressed by healthy Hematopoietic Stem Cells (HSCs), and is therefore a promising target for CAR-T-cell therapy. Here, we describe the development and optimization of an anti-CLL1 CAR-T-cell with potent activity on both AML cell lines and primary patient-derived AML blasts in vitro while sparing healthy HSCs. Furthermore, in a disseminated mouse xenograft model using the CLL1-positive HL60 cell line, these CAR-T-cells completely eradicated tumor, thus supporting CLL1 as a promising target for CAR-T-cells to treat AML while limiting myelosuppressive toxicity

Growth-Differentiation Factor 15 Predicts Worsening of Albuminuria in PatientsWith Type 2 Diabetes

OBJECTIVE-Development of micro- or macroalbuminuria is associated with increased risk of cardiorenal complications, particularly in diabetes. For prevention of transition to micro- or macroalbuminuria, more accurate prediction markers on top of classical risk markers are needed. We studied a promising new marker, growth-differentiation factor (GDF)-15, to predict transition to increasing stage of albuminuria in type 2 diabetes mellitus (T2DM). In addition, we looked at the GDF-15 potential in nondiabetic subjects with hypertension (HT). RESEARCH DESIGN AND METHODS-Case and control subjects were selected from the PREVEND cohort, a large (n = 8,592), prospective general population study on the natural course of albuminuria, with > 10 years of follow-up and repeated albuminuria measurements. We found 24 T2DM and 50 HT case subjects transitioning from normo- to macroalbuminuria and 9 T2DM and 25 HT case subjects transitioning from micro- to macroalbuminuria (average follow-up 2.8 years). Control subjects with stable albuminuria were pair matched for age, sex, albuminuria status, and diabetes duration. GDF-15 was measured in samples prior to albuminuria transition. RESULTS-Prior to transition, GDF-15 was significantly higher in case subjects with T2DM than in control subjects (median [IQR] 1,288 pg/mL [885-1,546] vs. 948 pg/mL [660-1,016], P <0.001). The odds ratio for transition in albuminuria increased significantly per SD of GDF-15 (2.9 [95% CI 1.1-7.5], P = 0.03). GDF-15 also improved prediction of albuminuria transition, with significant increases in C statistic (from 0.87 to 0.92, P = 0.03) and integrated discrimination improvement (0.148, P = 0.001). In HT, GDF-15 was also independently associated with transition in albuminuria stage (2.0 [1.1-3.5], P = 0.02) and improved prediction significantly. CONCLUSIONS-We identified GDF-15 as a clinically valuable marker for predicting transition in albuminuria stage in T2DM beyond conventional risk markers. These findings were confirmed in nondiabetic HT subjects

Growth differentiation factor 15 impairs aortic contractile and relaxing function through altered caveolar signaling of the endothelium

<p>Mazagova M, Buikema H, Landheer SW, Vavrinec P, van Buiten A, Henning RH, Deelman LE. Growth differentiation factor 15 impairs aortic contractile and relaxing function through altered caveolar signaling of the endothelium. Am J Physiol Heart Circ Physiol 304: H709-H718, 2013. First published December 21, 2012; doi:10.1152/ajpheart.00543.2012.-Growth differentiation factor 15 (GDF15) is an independent predictor of cardiovascular disease, and increased GDF15 levels have been associated with endothelial dysfunction in selected patients. We therefore investigated whether GDF15 modulates endothelial function in aortas of wild-type (WT) and GDF15 knockout (KO) mice. Vascular contractions to phenylephrine and relaxation to ACh were assessed in aortas obtained from healthy WT and GDF15 KO mice. The effects of GDF15 pretreatment and the involvement of ROS or caveolae were determined. Phenylephrine-induced contractions and ACh-mediated relaxations were similar in WT and GDF15 KO mice. Pretreatment with GDF15 inhibited contraction and relaxation in both groups. Inhibition of contraction by GDF15 was absent in denuded vessels or after blockade of nitric oxide (NO) synthase. Relaxation in WT mice was mediated mainly through NO and an unidentified endothelium-derived hyperpolarizin factor (EDHF), whereas GDF15 KO mice mainly used prostaglandins and EDHF. Pretreatment with GDF15 impaired relaxation in WT mice by decreasing NO; in GDF15 KO mice, this was mediated by decreased action of prostaglandins. Disruption of caveolae resulted in a similar inhibition of vascular responses as GDF15. ROS inhibition did not affect vascular function. In cultured endothelial cells, GDF15 pretreatment caused a dissociation between caveolin-1 and endothelial NO synthase. In conclusion, GDF15 impairs aortic contractile and relaxing function through an endothelium-dependent mechanism involving altered caveolar endothelial NO synthase signaling.</p>