PTEN mutation and EGFR amplification are important prognostic factors in patients with anaplastic astrocytoma and in older patients with glioblastoma multiforme, respectively.

Abstract-Cardiac fibroblasts (CFs) produce extracellular matrix proteins and participate in the remodeling of the heart.It is unknown if brain natriuretic peptide (BNP) is synthesized by CFs and if BNP participates in the regulation of extracellular matrix turnover. In this study, we examined the production of BNP in adult canine CFs and the role of BNP and its signaling system on collagen synthesis and on the activation of matrix metalloproteinases (MMPs Key Words: cardiac fibroblasts Ⅲ extracellular matrix Ⅲ remodeling Ⅲ cGMP Ⅲ protein kinase G T he cardiac interstitium is a dynamic structure, as reflected by continuous synthesis and degradation of matrix proteins. The family of matrix metalloproteinases (MMPs) consists of more than 20 different zinc-containing, Ca 2ϩ -dependent endopeptidases. 1,2 They degrade matrix proteins and therefore play an important role in the physiological regulation of the interstitium. The interstitial collagenases (MMP-1 and MMP-13), the stromelysin (MMP-3), the gelatinases (MMP-2 and MMP-9), and membranous-type 1 MMPs (MMP-14; MT1-MMP) have been demonstrated within the mammalian myocardium. 2 Furthermore, dysregulation of MMP proteins and their endogenous inhibitor, tissue inhibitors of MMP (TIMP), has been observed in the hypertensive and the failing heart, suggesting an important role of MMP in the process of ventricular remodeling. [3][4][5][6][7] Cardiac fibroblasts (CFs) play a crucial role in the regulation of the extracellular matrix (ECM) of the heart by synthesizing collagen and other matrix proteins as well as promoting their degradation by secreting MMP proteins. In response to myocardial injury, activation of CFs occurs. These activated CFs (myofibroblasts) have special morphological and functional characteristics. 8,9 The natriuretic peptides (NPs) atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) play important roles in maintaining cardiorenal homeostasis under physiological and pathological conditions. 10 ANP and BNP are synthesized by cardiomyocytes, and their production is stimulated in pathologic conditions such as myocardial infarction (MI), cardiac hypertrophy, and heart failure (HF). 11-13 ANP and BNP have natriuretic, vasodilating, and lusitropic properties, and they inhibit the sympathetic and renin-angiotensin-aldosterone system. 14,15 These actions are primarily mediated by the second messenger cGMP. 16 Cameron et al 17 have recently reported that ANP is produced in CFs after MI, indicating that fibroblasts, like cardiomyocytes, can be a source of NPs. However, it remains unknown if BNP is produced by CFs.Although it is well established that BNP has growthinhibiting properties in the heart, 18 -21 the role of BNP on the regulation of the cardiac interstitium remains undefined. Given the widespread cross-talk of the NPs with other systems that are activated in cardiorenal disorders, we aimed to investigate whether CFs are a source of BNP and whether BNP and its signaling system contribute to the regulation of Original

Objectives Our aim was to design, synthesize and test in vivo and in vitro a new chimeric peptide that would combine the beneficial properties of 2 distinct natriuretic peptides with a biological profile that goes beyond native peptides. Background Studies have established the beneficial vascular and antiproliferative properties of C-type natriuretic peptide (CNP). While lacking renal actions, CNP is less hypotensive than the cardiac peptides atrial natriuretic peptide and B-type natriuretic peptide but unloads the heart due to venodilation. Dendroaspis natriuretic peptide is a potent natriuretic and diuretic peptide that is markedly hypotensive and functions via a separate guanylyl cyclase receptor compared with CNP. Methods Here we engineered a novel chimeric peptide CD-NP that represents the fusion of the 22-amino acid peptide CNP together with the 15-amino acid linear C-terminus of Dendroaspis natriuretic peptide. We also determined in vitro in cardiac fibroblasts cyclic guanosine monophosphate-activating and antiproliferative properties of CD-NP. Results Our studies demonstrate in vivo that CD-NP is natriuretic and diuretic, glomerular filtration rate enhancing, cardiac unloading, and renin inhibiting. CD-NP also demonstrates less hypotensive properties when compared with B-type natriuretic peptide. In addition, CD-NP in vitro activates cyclic guanosine monophosphate and inhibits cardiac fibroblast proliferation. Conclusions The current findings advance an innovative design strategy in natriuretic peptide drug discovery and development to create therapeutic peptides with favorable properties that may be preferable to those associated with native natriuretic peptides.

BACKGROUND B-type natriuretic peptide (BNP), which is activated in heart failure (HF), is processed to an active form by corin. The corin gene is expressed in the human heart and kidney, but corin protein expression in the heart, kidney, and circulation, along with whether proBNP is processed by circulating corin, remains unknown. METHODS We examined corin protein expression by immunostaining and Western blot in human heart and kidney, and we assessed the circulating corin concentration by ELISA. We examined histidine-tagged (His-tag) proBNP1–108 processing in serum and plasma by immunoprecipitation and Western blot and sequenced the processed form. RESULTS Normal human heart and kidney displayed the presence of corin, especially in cells around the vasculature. Both corin and proBNP1–108 were present in the plasma of healthy human subjects, with circulating corin significantly higher in men than women (P < 0.0001) and a positive correlation of corin to age (P = 0.0497, r = 0.27). In fresh normal plasma and serum, His-tag proBNP1–108 was processed to a lower molecular weight form confirmed to be BNP. Processed BNP was higher in men than women (P = 0.041) and was positively correlated to plasma corin concentrations (P = 0.041, r = 0.65). CONCLUSIONS Our results support the concept that proBNP1–108 may be processed outside of the heart in the circulation where the proprotein convertase is present. Moreover, sex may impact this process, since corin concentrations are higher in men. These findings may have important physiologic and pathophysiologic implications for the proBNP/corin system in the human.

Abstract-Recent studies support the speculation that different molecular forms of the cardiac hormone BNP with differential biological activity may circulate in heart failure and be detected by conventional assays. In the current study we determined the ability of 3 widely used conventional assays to detect these different forms thought to circulate in heart failure. We also evaluated the ability of pro-BNP (1-108), N-terminal peptide (NT)-pro-BNP (1-76), and BNP 3-32, the latter a cleavage product of BNP 1-32 by dipeptidyl peptidase IV, on an equimolar basis to activate cGMP in cultured cardiac fibroblasts and cardiomyocytes compared with the biologically active mature BNP 1-32. Specifically, we observed that the Roche NT-pro-BNP assay detected both NT-pro-BNP 1-76 and pro-BNP 1-108 and that Biosite Triage and Shionogi detected both mature BNP 1-32 and the shortened BNP 3-32. Moreover, in cultured cardiac fibroblasts and cardiomyocytes, BNP 1-32 (10 Ϫ6 mol/L) activated cGMP. BNP 3-32 demonstrated a similar cGMP activating property in both cardiac cell types. In contrast, the cGMP response to pro-BNP 1-108 and NT-pro-BNP 1-76 was not significantly greater than no treatment alone. We conclude that widely used commercial assays for NT-pro-BNP 1-76 and BNP 1-32 cannot differentiate among pro-, processed, or degraded forms and, thus, may not thoroughly identify circulating BNP forms in heart failure patients. These findings also demonstrate differential cGMP activating properties of BNP forms and, importantly, that pro-BNP 1-108 and NT-pro-BNP 1-76 have reduced cGMP activity in vitro that may have biological relevance to human heart failure.

Myocardial aging is characterized by LV fibrosis leading to diastolic and systolic dysfunction. Studies have established the potent anti-fibrotic and anti-proliferative properties of C-type natriuretic peptide (CNP), however the relationship between circulating CNP, LV fibrosis and associated changes in LV function with natural aging are undefined. Accordingly, we characterized the relationship of plasma CNP with LV fibrosis and function in 2, 11 and 20 month old male Fischer rats. Further in vitro, we establish the anti-proliferative actions of CNP and the participation of the clearance receptor using adult human cardiac fibroblasts. Here we establish for the first time that a progressive decline in circulating CNP characterizes natural aging and is strongly associated with a reciprocal increase in LV fibrosis which precedes impairment of diastolic and systolic function. Additionally we demonstrate in cultured adult human cardiac fibroblasts that the direct anti-proliferative actions of high dose CNP may involve a non-cGMP pathway via the clearance receptor. Taken together these studies provide new insights into myocardial aging and the relationship to the anti-fibrotic and anti-proliferative peptide CNP.

After therapeutic hormone deprivation, pros-

Comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), polymerase chain reaction-based microsatellite analysis, and p53 sequencing were performed in paraffin-embedded material from 18 oligodendrogliomas and histologically similar astrocytomas. The study was undertaken because of evidence that concurrent loss of both the 1p and 19q chromosome arms is a specific marker for oligodendrogliomas. Of the six lesions with a review diagnosis of oligodendroglioma, all had the predicted loss of 1p and 19q seen by CGH, FISH, and polymerase chain reaction. Other lesions, including some considered oligodendroglioma or mixed glioma by the submitting institution, did not. There were no p53 mutations in any of the six oligodendrogliomas, whereas 5 of the 10 remaining, successfully studied cases did have p53 mutations. The results suggest that CGH and FISH performed on current or archival tissue can aid in classification of infiltrating gliomas such as oligodendrogliomas and astrocytomas. The results of the p53 studies are consistent with findings of previous investigations that such mutations are less common in oligodendrogliomas than they are in astrocytomas.