Loss of the long non-coding RNA OIP5-AS1 exacerbates heart failure in a sex-specific manner.

Long non-coding RNAs (lncRNAs) have been demonstrated to influence numerous biological processes, being strongly implicated in the maintenance and physiological function of various tissues including the heart. The lncRNA OIP5-AS1 (/C) has been studied in several settings; however its role in cardiac pathologies remains mostly uncharacterized. Using a series of and methods, we demonstrate that OIP5-AS1 is regulated during cardiac development in rodent and human models and in disease settings in mice.

Coexpressed Class B G Protein-Coupled Secretin and GLP-1 Receptors Self- and Cross-Associate: Impact on Pancreatic Islets.

Class B guanine nucleotide-binding protein (G protein)-coupled receptors form symmetrical homodimeric complexes along the lipid face of transmembrane segment 4 (TM4) and can form heterodimeric complexes, although their structure is unknown. The current study demonstrates that the lipid face of TM4 is also the predominant determinant for formation of heteroreceptor complexes between two class B receptors, secretin receptor (SecR) and glucagonlike peptide-1 receptor (GLP-1R), which are expressed on pancreatic islet cells. Because these receptors use the same interface for formation of homo- and heteroreceptor complexes, competitive forces may affect expression of different complexes.

HCN channelopathy and cardiac electrophysiologic dysfunction in genetic and acquired rat epilepsy models.

Objective: Evidence from animal and human studies indicates that epilepsy can affect cardiac function, although the molecular basis of this remains poorly understood. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels generate pacemaker activity and modulate cellular excitability in the brain and heart, with altered expression and function associated with epilepsy and cardiomyopathies. Whether HCN expression is altered in the heart in association with epilepsy has not been investigated previously.

Enhanced extravasation, stability and in vivo cardiac gene silencing via in situ siRNA-albumin conjugation.

A potential barrier to progression of siRNA therapeutics to the clinic is the ability of these agents to cross the vascular endothelium to reach target cells. This study aimed to bypass the endothelial barrier by harnessing the extravasation capability of the serum protein albumin to allow siRNA to reach cardiomyocytes. A strategy for conjugating siRNA to albumin in vivo was developed that involved activating 3'-amine, 2'-O-methyl, phosphorothioate modified siRNA with succinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (SMCC) to yield maleimide-functionalized siRNA ("activated siRNA"); this thiol-reactive species can then irreversibly link to the single surface-exposed cysteine residue of endogenous albumin following intravenous administration.

Commercially Supplied Amine-Modified siRNAs May Require Ultrafiltration prior to Conjugation with Amine-Reactive Compounds.

Conjugation of siRNA to macromolecules such as serum albumin has multiple potential benefits, including enhanced extravasation via albumin-mediated transcytosis across endothelial cells and reduced renal clearance. In attempting to conjugate siRNA to albumin, we used commercially sourced amine-modified siRNA and reacted it with the heterobifunctional linker succinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (SMCC) to introduce a maleimide group suitable for conjugation to the thiol group of the surface-exposed cysteine residue (Cys 34) within albumin. We found the conjugation of the SMCC-treated siRNA to bovine serum albumin (BSA) to be very inefficient and investigated the cause of the low yield of conjugate.

Characterization of the acute cardiovascular effects of intravenously administered insulin-like growth factor-I in conscious Sprague-Dawley rats.

1. Insulin-like growth factor (IGF)-I has acute effects on cardiovascular function, including a well-characterized vasodilator response in isolated arteries. In addition to increasing the release of nitric oxide, IGF-I also has effects on a variety of other signalling pathways that affect vascular tone, in particular interactions with the sympathetic nervous system and the renin-angiotensin-aldosterone system.