direct-detection-isolevuglandins-tissues-using-d11-scfv-alkaline

Direct Detection of Isolevuglandins in Tissues Using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence

Isolevuglandins (IsoLGs) are highly reactive gamma ketoaldehydes formed from H2-isoprostanes through lipid peroxidation and crosslink proteins leading to ...

Vanderbilt University

Metastatic breast cancer is an incurable disease and identification of novel therapeutic opportunities is vital. Triple-negative breast cancer (TNBC) frequently metastasizes and high levels of activated p90RSK (RSK), a downstream MEK-ERK1/2 effector, are found in TNBC. We demonstrate, using direct pharmacologic and genetic inhibition of RSK1/2, that these kinases contribute to the TNBC metastatic process in vivo Kinase profiling showed that RSK1 and RSK2 are the predominant kinases targeted by the new inhibitor, which is based on the natural product SL0101. Further evidence for selectivity was provided by the observations that silencing RSK1 and RSK2 eliminated the ability of the analogue to further inhibit survival or proliferation of a TNBC cell line. In vivo, the new derivative was as effective as the FDA-approved MEK inhibitor trametinib in reducing the establishment of metastatic foci. Importantly, inhibition of RSK1/2 did not result in activation of AKT, which is known to limit the efficacy of MEK inhibitors in the clinic. Our results demonstrate that RSK is a major contributor to the TNBC metastatic program and provide preclinical proof-of-concept for the efficacy of the novel SL0101 analogue in vivo Mol Cancer Ther; 15(11); 2598-608. ©2016 AACR.

Development of a RSK Inhibitor as a Novel Therapy for Triple-Negative Breast Cancer.

Excess dietary salt contributes to inflammation and hypertension via poorly understood mechanisms. Antigen presenting cells including dendritic cells (DCs) play a key role in regulating intestinal immune homeostasis in part by surveying the gut epithelial surface for pathogens. Previously, we found that highly reactive γ-ketoaldehydes or isolevuglandins (IsoLGs) accumulate in DCs and act as neoantigens, promoting an autoimmune-like state and hypertension. We hypothesized that excess dietary salt alters the gut microbiome leading to hypertension and this is associated with increased immunogenic IsoLG-adduct formation in myeloid antigen presenting cells. To test this hypothesis, we performed fecal microbiome analysis and measured blood pressure of healthy human volunteers with salt intake above or below the American Heart Association recommendations. We also performed 16S rRNA analysis on cecal samples of mice fed normal or high salt diets. In humans and mice, high salt intake was associated with changes in the gut microbiome reflecting an increase in Firmicutes, Proteobacteria and genus Prevotella bacteria. These alterations were associated with higher blood pressure in humans and predisposed mice to vascular inflammation and hypertension in response to a sub-pressor dose of angiotensin II. Mice fed a high salt diet exhibited increased intestinal inflammation including the mesenteric arterial arcade and aorta, with a marked increase in the B7 ligand CD86 and formation of IsoLG-protein adducts in CD11c+ myeloid cells. Adoptive transfer of fecal material from conventionally housed high salt-fed mice to germ-free mice predisposed them to increased intestinal inflammation and hypertension. These findings provide novel insight into the mechanisms underlying inflammation and hypertension associated with excess dietary salt and may lead to interventions targeting the microbiome to prevent and treat this important disease.

High dietary salt-induced dendritic cell activation underlies microbial dysbiosis-associated hypertension.

CD148 is a transmembrane protein tyrosine phosphatase (PTP) that is expressed in the renal vasculature, including the glomerulus. Previous studies have shown that CD148 plays a role in the negative regulation of growth factor signals (including epidermal growth factor and vascular endothelial growth factor), suppressing cell proliferation and transformation. However, the role of CD148 in kidney disease remains unknown. Here, we generated an agonistic anti-CD148 antibody and evaluated its effects in murine diabetic nephropathy (DN). Monoclonal antibodies (mAbs) against the mouse CD148 ectodomain sequence were generated by immunizing CD148 knockout (CD148KO) mice. The mAbs that increased CD148 activity were selected by biological (proliferation) and biochemical (PTP activity) assays. The mAb (18E1) that showed strong agonistic activity was injected (10 mg/kg ip) in streptozotocin-induced wild-type and CD148KO diabetic mice for 6 wk, and the renal phenotype was then assessed. The effects of 18E1 mAb in podocyte growth factor signals were also assessed in culture. Compared with control IgG, 18E1 mAb significantly decreased albuminuria and mesangial expansion without altering hyperglycemia and blood pressure in wild-type diabetic mice. Immunohistochemical evaluation showed that 18E1 mAb significantly prevented the reduction of podocyte number and nephrin expression and decreased glomerular fibronectin expression and renal macrophage infiltration. The 18E1 mAb showed no effects in CD148KO diabetic mice. Furthermore, we demonstrated that 18E1 mAb reduces podocyte epidermal growth factor receptor signals in culture and in diabetic mice. These findings suggest that agonistic anti-CD148 mAb attenuates DN in mice, in part by reducing epidermal growth factor receptor signals in podocytes. This antibody may be used for the treatment of early DN.

Lejla Pasic

Department of Biochemistry

Vanderbilt University

Direct Detection of Isolevuglandins in Tissues Using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence

Lejla Pasic

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Biochemistry

Vanderbilt University

Direct Detection of Isolevuglandins in Tissues Using a D11 scFv-Alkaline Phosphatase Fusion Protein and Immunofluorescence

Department of Biochemistry