Concerted Regulation of cGMP and cAMP Phosphodiesterases in Early Cardiac Hypertrophy Induced by Angiotensin II

Left ventricular hypertrophy leads to heart failure and represents a high risk leading to premature death. Cyclic nucleotides (cAMP and cGMP) play a major role in heart contractility and cyclic nucleotide phosphodiesterases (PDEs) are involved in different stages of advanced cardiac diseases. We have investigated their contributions in the very initial stages of left ventricular hypertrophy development. Wistar male rats were treated over two weeks by chronic infusion of angiotensin II using osmotic mini-pumps. Left cardiac ventricles were used as total homogenates for analysis. PDE1 to PDE5 specific activities and protein and mRNA expressions were explored

The science of statistics versus data science: What is the future?

The importance and relevance of the discipline of statistics with the merits of the evolving field of data science continues to be debated in academia and industry. Following a narrative literature review with over 100 scholarly and practitioner-oriented publications from statistics and data science, this article generates a pragmatic perspective on the relationships and differences between statistics and data science. Some data scientists argue that statistics is not necessary for data science as statistics delivers simple explanations and data science delivers results. Therefore, this article aims to stimulate debate and discourse among both academics and practitioners in these fields. The findings reveal the need for stakeholders to accept the inherent advantages and disadvantages within the science of statistics and data science. The science of statistics enables data science (aiding its reliability and validity), and data science expands the application of statistics to Big Data. Data scientists should accept the contribution and importance of statistics and statisticians must humbly acknowledge the novel capabilities made possible through data science and support this field of study with their theoretical and pragmatic expertise. Indeed, the emergence of data science does pose a threat to statisticians, but the opportunities for synergies are far greater

cGMP-Hydrolytic Activity and Its Inhibition by Sildenafil in Normal and Failing Human and Mouse Myocardium

In mouse models of cardiac disease, the type 5 (PDE5)-selective cyclic nucleotide phosphodiesterase inhibitor sildenafil has antihypertrophic and cardioprotective effects attributable to the inhibition of cGMP hydrolysis. To investigate the relevance of these findings to humans, we quantified cGMP-hydrolytic activity and its inhibition by sildenafil in cytosolic and microsomal preparations from the left ventricular myocardium of normal and failing human hearts. The vast majority of cGMP-hydrolytic activity was attributable to PDE1 and PDE3. Sildenafil had no measurable effect on cGMP hydrolysis at 10 nM, at which it is selective for PDE5, but it had a marked effect on cGMP and cAMP hydrolysis at 1 μM, at which it inhibits PDE1. In contrast, in preparations from the left ventricles of normal mice and mice with heart failure resulting from coronary artery ligation, the effects of sildenafil on cGMP hydrolysis were attributable to inhibition of both PDE5 and PDE1; PDE5 comprised ∼22 and ∼43% of the cytosolic cGMP-hydrolytic activity in preparations from normal and failing mouse hearts, respectively. These differences in PDE5 activities in human and mouse hearts call into question the extent to which the effects of sildenafil in mouse models are likely to be applicable in humans and raise the possibility of PDE1 as an alternative therapeutic target

Selective regulation of cyclic nucleotide phosphodiesterase PDE3A isoforms

Inhibitors of cyclic nucleotide phosphodiesterase (PDE) PDE3A increase cardiac contractility in patients with heart failure, but their long-term use increases mortality. Two isoforms expressed in cardiac myocytes, PDE3A1 and PDE3A2, have amino acid sequences that are identical except for a unique N-terminal extension in PDE3A1. We found that PDE3A1 and PDE3A2 are selectively phosphorylated at alternative sites in response to the activation of PKA and PKC, respectively, resulting in differential regulation of their catalytic activity and protein interactomes. Existing PDE3 inhibitors thus target at least two functionally distinct cardiac isoforms likely with different roles in intracellular signaling. This raises the possibility that isoform-selective targeting may increase contractility in failing hearts without increasing mortality, providing a potential route for developing therapeutics

The metastasis suppressor gene KiSS-1 encodes kisspeptins, the natural ligands of the orphan G protein-coupled receptor GPR54

Natural peptides displaying agonist activity on the orphan G protein-coupled receptor GPR54 were isolated from human placenta. These 54-, 14,- and 13-amino acid peptides, with a common RF-amide C terminus, derive from the product of KiSS-1, a metastasis suppressor gene for melanoma cells, and were therefore designated kisspeptins. They bound with low nanomolar affinities to rat and human GPR54 expressed in Chinese hamster ovary K1 cells and stimulated PIP(2) hydrolysis, Ca(2+) mobilization, arachidonic acid release, ERK1/2 and p38 MAP kinase phosphorylation, and stress fiber formation but inhibited cell proliferation. Human GPR54 was highly expressed in placenta, pituitary, pancreas, and spinal cord, suggesting a role in the regulation of endocrine function. Stimulation of oxytocin secretion after kisspeptin administration to rats confirmed this hypothesis.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

AFLP-based transcript profiling (cDNA-AFLP) for genome-wide expression analysis

Although DNA microarrays are currently the standard tool for genome-wide expression analysis, their application is limited to organisms for which the complete genome sequence or large collections of known transcript sequences are available. Here, we describe a protocol for cDNA-AFLP, an AFLP-based transcript profiling method that allows genome-wide expression analysis in any species without the need for prior sequence knowledge. In essence, the cDNA-AFLP method involves reverse transcription of mRNA into double-stranded cDNA, followed by restriction digestion, ligation of specific adapters and fractionation of this mixture of cDNA fragments into smaller subsets by selective PCR amplification. The resulting cDNA-AFLP fragments are separated on high-resolution gels, and visualization of cDNA-AFLP fingerprints is described using either a conventional autoradiography platform or an automated LI-COR system. Observed differences in band intensities between samples provide a good measure of the relative differences in the gene expression levels. Identification of differentially expressed genes can be accomplished by purifying cDNA-AFLP fragments from sequence gels and subsequent sequencing. This method has found widespread use as an attractive technology for gene discovery on the basis of fragment detection and for temporal quantitative gene expression analysis. The protocol can be completed in 3-4 d