Novel Evidence of PLC δ2 Involvement in the Regulation of the Differential Evolution of Aneurysms

Rat Basophilic Leukemia Cells (RBL-2H3) Generate Prostaglandin D2 (PGD2) after Regulated upon Activation, Normal T-cell Expressed and Secreted (RANTES) activation

Increasing evidence indicates that local neurogenic inflammation, possibly in response to different stimuli, may be involved in sensory nerve sensitization, migraine generation and some other precipitating events leading to neuronal dysfunction in the brain. In addition, mast cells generate eicosanoids that are linked to asthma and other inflammatory diseases. Regulated upon activation, normal T-cell expressed and secreted (RANTES) is a small protein and a prototype member of the CC chemokine-beta subfamily with chemoattractant and inflammatory properties. In this study we used the RBL-2H3 cell line to determine whether or not these cells generate prostaglandin D2 (PGD2) after treatment with RANTES. After 4 hours of incubation, RBL-2H3 cells cultured with RANTES at 20 ng/mL released large amounts of PGD2 in a dose-response manner compared to control. Moreover, RBL-treated RANTES generated a large quantity of histamine. Our study confirms once again the proinflammatory action of RANTES, in this case acting on the stimulation of the arachidonic acid cascade product PGD2.

Molecular Genetics of Human Intracranial Aneurysms

Intracranial aneurysms (IAs) are the dilatations of blood vessels in the brain and pose potential risk of rupture leading to subarachnoid hemorrhage. Although the genetic basis of IAs is poorly understood, it is well-known that genetic factors play an important part in the pathogenesis of IAs. Therefore, the identifying susceptible genetic variants might lead to the understanding of the mechanism of formation and rupture of IAs and might also lead to the development of a pharmacological therapy. To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although extensive genetic research and its potential implications for future prevention of this often fatal condition are urgently needed, efforts to elucidate the susceptibility loci of IAs are hindered by the issues bewildering the most common and complex genetic disorders, such as low penetrance, late onset, and uncertain modes of inheritance. These efforts are further complicated by the fact that many IA lesions remain asymptomatic or go undiagnosed. In this review, we present and discuss the current status of genetic studies of IAs and we recommend comprehensive genome-wide association studies to identify genetic loci that underlie this complex disease.

Differential protein kinase C isoform abundance in ascending aortic aneurysms from patients with bicuspid versus tricuspid aortic valves

BACKGROUND

It is recognized that different events contribute to the initiation of ascending thoracic aortic aneurysms (ATAAs) in patients with bicuspid aortic valves (BAV) versus patients with tricuspid aortic valves (TAV), but the molecular signaling pathways driving aneurysm formation remain unclear. Protein kinase C (PKC) is a superfamily of kinases which differentially mediate signaling events that lead to altered gene expression and cellular function, and may regulate downstream mediators of vascular remodeling. The present study tested the hypothesis that ATAA development in patients with BAV versus TAV proceeds by independent signaling pathways involving differential PKC signaling.

METHODS AND RESULTS

ATAA samples were collected from BAV (n=57) and TAV (n=55) patients and assessed for 10 different PKC isoforms by immunoblotting. Results were expressed as a percent change in abundance (mean+/-SEM) from a nonaneurysmal control group (100%, n=21). Correlation analysis was performed, and relationships between PKC and matrix metalloproteinase abundance were reported. In the BAV group, classic and novel PKC isoforms (PKC-alpha, betaI, gamma, epsilon, theta) were increased, whereas PKC-eta and atypical PKC-zeta were decreased. In the TAV group, classic and novel isoforms were decreased and atypical PKC-zeta was elevated. Positive correlations between PKC and matrix metalloproteinase abundance were identified.

CONCLUSIONS

Differential PKC isoform abundance was observed in ATAA samples from patients with BAV versus TAV, suggesting independent molecular signaling pathways may be operative. Induction of independent transcriptional programs may result and may provide a mechanistic foundation for developing selective diagnostic/therapeutic strategies for patients with ATAAs secondary to BAV or TAV.

Nuclear protein kinase C-delta: a possible check-point of cell cycle progression

Protein kinase Cs (PKCs) belong to a serine/threonine kinase family, ubiquitously expressed and claimed to be involved in physiological processes including apoptosis, cell growth and differentiation. The question of the subcellular localization and activity of PKCs remains to be clarified. Here we report that nuclear PKC-delta cooperates to regulate the S-G2/M phase transition of cell cycle, apparently being associated to chromosome condensation and alignment on the metaphase plate.