Cyclin-dependent kinase 5 mediates pleiotrophin-induced endothelial cell migration

Pleiotrophin (PTN) stimulates endothelial cell migration through binding to receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) and ανβ3 integrin. Screening for proteins that interact with RPTPβ/ζ and potentially regulate PTN signaling, through mass spectrometry analysis, identified cyclin-dependent kinase 5 (CDK5) activator p35 among the proteins displaying high sequence coverage. Interaction of p35 with the serine/threonine kinase CDK5 leads to CDK5 activation, known to be implicated in cell migration. Protein immunoprecipitation and proximity ligation assays verified p35-RPTPβ/ζ interaction and revealed the molecular association of CDK5 and RPTPβ/ζ. In endothelial cells, PTN activates CDK5 in an RPTPβ/ζ- and phosphoinositide 3-kinase (PI3K)-dependent manner. On the other hand, c-Src, ανβ3 and ERK1/2 do not mediate the PTN-induced CDK5 activation. Pharmacological and genetic inhibition of CDK5 abolished PTN-induced endothelial cell migration, suggesting that CDK5 mediates PTN stimulatory effect. A new pyrrolo[2,3-α]carbazole derivative previously identified as a CDK1 inhibitor, was found to suppress CDK5 activity and eliminate PTN stimulatory effect on cell migration, warranting its further evaluation as a new CDK5 inhibitor. Collectively, our data reveal that CDK5 is activated by PTN, in an RPTPβ/ζ-dependent manner, regulates PTN-induced cell migration and is an attractive target for the inhibition of PTN pro-angiogenic properties

Applying pattern recognition methods to analyze the molecular properties of a homologous series of nitrogen mustard agents

The purpose of this research was to analyze the pharmacological properties of a homologous series of nitrogen mustard (N-mustard) agents formed after inserting 1 to 9 methylene groups (-CH2-) between 2-N(CH2CH2Cl)2 groups. These compounds were shown to have significant correlations and associations in their properties after analysis by pattern recognition methods including hierarchical classification, cluster analysis, nonmetric multi-dimensional scaling (MDS), detrended correspondence analysis, K-means cluster analysis, discriminant analysis, and self-organizing tree algorithm (SOTA) analysis. Detrended correspondence analysis showed a linear-like association of the 9 homologs, and hierarchical classification showed that each homolog had great similarity to at least one other member of the series—as did cluster analysis using paired-group distance measure. Nonmetric multi-dimensional scaling was able to discriminate homologs 2 and 3 (by number of methylene groups) from homologs 4, 5, and 6 as a group, and from homologs 7, 8, and 9 as a group. Discriminant analysis, K-means cluster analysis, and hierarchical classification distinguished the high molecular weight homologs from low molecular weight homologs. As the number of methylene groups increased the aqueous solubility decreased, dermal permeation coefficient increased, Log P increased, molar volume increased, parachor increased, and index of refraction decreased. Application of pattern recognition methods discerned useful interrelationships within the homologous series that will determine specific and beneficial clinical applications for each homolog and methods of administration

IL-33 and ST2 levels in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events, and survival

Increased inflammation, associated with the increase in chronic kidney disease (CKD) stage, has a very important influence in vascular injury and cardiovascular diseases. In this study, we aimed to investigate the levels of IL-33 and ST2 in the different stages of CKD and to determine their effect on vascular damage and cardiovascular events (CVE).This was an observational cohort study in which serum IL-33 and ST2 were obtained from 238 CKD (stages 1-5) patients. We examined the changes in IL-33/ST2 levels in CKD patients, as well as the association with a surrogate of endothelial dysfunction. Fatal and non-fatal CVE were recorded for a mean of 24 months. We also performed a COX regression analysis to determine the association of IL-33/ST2 levels with CVE and survival.IL-33 and ST2 levels were significantly increased and estimated glomerular filtration rates (eGFR) were decreased. Flow-mediated dilatation (FMD) was significantly decreased from stage 1 to stage 5 CKD. IL-33 and ST2 levels were associated with FMD, and ST2 was a predictor. Multivariate Cox analysis showed that the presence of diabetes mellitus, smoking, and proteinuria and haemoglobin, Hs-CRP, IL-33, and ST2 were associated with the risk of CVE. Kaplan-Meier survival curves showed that patients with IL-33 and ST2 levels below the median value (IL-33 = 132.6 ng/L, ST2 = 382.9 pg/mL) had a higher cumulative survival compared with patients who had IL-33 and ST2 levels above the median value (log-rank test, p = 0.000).This is the first study that demonstrates that serum IL-33 and ST2 are associated with vascular injury, cardiovascular events, and survival in CKD patients