With the increased attention focused on active learning, educators strive to find better and more innovative ways to engage students in the classroom. One of the hurtles that educators are presented with is that the classroom is no longer limited to a physical location but rather students and professor can meet via the internet, Before COVID-19, distance or remote learning was something that students, by and large, had the option of choosing in which whether to engage. Students had the option to take "online courses," whether those be synchronous remote learning or asynchronous online courses.
View Article and Find Full Text PDFThe traditional case study has been used as a learning tool for the past 100 years, and in our program, graduate physiology students are presented with a real-world scenario and must determine the diagnosis and treatment of the patient. We found that students defaulted to memorization of disease with treatment and bypassed gaining an understanding of the mechanistic physiology behind disease and treatment. To adjust our student's approach, we developed a novel way to enhance student learning.
View Article and Find Full Text PDFCardiac two-pore domain potassium channels (K2P) exist in organisms from Drosophila to humans; however, their role in cardiac function is not known. We identified a K2P gene, CG8713 (sandman), in a Drosophila genetic screen and show that sandman is critical to cardiac function. Mice lacking an ortholog of sandman, TWIK-related potassium channel (TREK-1, also known Kcnk2), exhibit exaggerated pressure overload-induced concentric hypertrophy and alterations in fetal gene expression, yet retain preserved systolic and diastolic cardiac function.
View Article and Find Full Text PDFβ2-Adrenergic receptors (β2AR) transactivate epidermal growth factor receptors (EGFR) through formation of a β2AR-EGFR complex that requires activation of Src to mediate signaling. Here, we show that both lipid and protein kinase activities of the bifunctional phosphoinositide 3-kinase (PI3K) enzyme are required for β2AR-stimulated EGFR transactivation. Mechanistically, the generation of phosphatidylinositol (3,4,5)-tris-phosphate (PIP3) by the lipid kinase function stabilizes β2AR-EGFR complexes while the protein kinase activity of PI3K regulates Src activation by direct phosphorylation.
View Article and Find Full Text PDFBackground: Whether biomechanical force on the heart can induce exosome secretion to modulate cardiovascular function is not known. We investigated the secretion and activity of exosomes containing a key receptor in cardiovascular function, the angiotensin II type I receptor (AT1R).
Methods And Results: Exosomes containing AT1Rs were isolated from the media overlying AT1R-overexpressing cells exposed to osmotic stretch and from sera of mice undergoing cardiac pressure overload.
Derangements in metabolism and related signaling pathways characterize the failing heart. One such signal, O-linked β-N-acetylglucosamine (O-GlcNAc), is an essential post-translational modification regulated by two enzymes, O-GlcNAc transferase and O-GlcNAcase (OGA), which modulate the function of many nuclear and cytoplasmic proteins. We recently reported reduced OGA expression in the failing heart, which is consistent with the pro-adaptive role of increased O-GlcNAcylation during heart failure; however, molecular mechanisms regulating these enzymes during heart failure remain unknown.
View Article and Find Full Text PDFBackground: Cardiac hypertrophy and heart failure are associated with metabolic dysregulation and a state of chronic energy deficiency. Although several disparate changes in individual metabolic pathways have been described, there has been no global assessment of metabolomic changes in hypertrophic and failing hearts in vivo. Hence, we investigated the impact of pressure overload and infarction on myocardial metabolism.
View Article and Find Full Text PDFPreclinical studies of animals with risk factors, and how those risk factors contribute to the development of cardiovascular disease and cardiac dysfunction, are clearly needed. One such approach is to feed mice a diet rich in fat (i.e.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
January 2014
The singly coded gene O-linked-β-N-acetylglucosamine (O-GlcNAc) transferase (Ogt) resides on the X chromosome and is necessary for embryonic stem cell viability during embryogenesis. In mature cells, this enzyme catalyzes the posttranslational modification known as O-GlcNAc to various cellular proteins. Several groups, including our own, have shown that acute increases in protein O-GlcNAcylation are cardioprotective both in vitro and in vivo.
View Article and Find Full Text PDFThis study was designed to test whether reduced levels of cardiac fructose-2,6-bisphosphate (F-2,6-P(2)) exacerbates cardiac damage in response to pressure overload. F-2,6-P(2) is a positive regulator of the glycolytic enzyme phosphofructokinase. Normal and Mb transgenic mice were subject to transverse aortic constriction (TAC) or sham surgery.
View Article and Find Full Text PDFThe regulation of cardiomyocyte hypertrophy is a complex interplay among many known and unknown processes. One specific pathway involves the phosphatase calcineurin, which regulates nuclear translocation of the essential cardiac hypertrophy transcription factor, nuclear factor of activated T-cells (NFAT). Although metabolic dysregulation is frequently described during cardiac hypertrophy, limited insights exist regarding various accessory pathways.
View Article and Find Full Text PDFCardiac failure is associated with increased levels of oxidized DNA, especially mitochondrial (mtDNA). It is not known if oxidized mtDNA contributes to cardiac dysfunction. To test if protection of mtDNA can reduce cardiac injury, we produced transgenic mice with cardiomyocyte-specific overexpression of the DNA repair enzyme 8-oxoguanine DNA glycosylase 1 (OGG1) isoform 2a.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2010
The failing heart is subject to elevated metabolic demands, adverse remodeling, chronic apoptosis, and ventricular dysfunction. The interplay among such pathologic changes is largely unknown. Several laboratories have identified a unique posttranslational modification that may have significant effects on cardiovascular function.
View Article and Find Full Text PDFO-linked β-N-acetylglucosamine (O-GlcNAc) is an inducible, dynamically cycling and reversible post-translational modification of Ser/Thr residues of nucleocytoplasmic and mitochondrial proteins. We recently discovered that O-GlcNAcylation confers cytoprotection in the heart via attenuating the formation of mitochondrial permeability transition pore (mPTP) and the subsequent loss of mitochondrial membrane potential. Because Ca(2+) overload and reactive oxygen species (ROS) generation are prominent features of post-ischemic injury and favor mPTP formation, we ascertained whether O-GlcNAcylation mitigates mPTP formation via its effects on Ca(2+) overload and ROS generation.
View Article and Find Full Text PDFO-linked beta-N-acetylglucosamine (O-GlcNAc) is a dynamic, inducible, and reversible post-translational modification of nuclear and cytoplasmic proteins on Ser/Thr amino acid residues. In addition to its putative role as a nutrient sensor, we have recently shown pharmacologic elevation of O-GlcNAc levels positively affected myocyte survival during oxidant stress. However, no rigorous assessment of the contribution of O-GlcNAc transferase has been performed, particularly in the post-hypoxic setting.
View Article and Find Full Text PDFDuring ischemia and heart failure, there is an increase in cardiac glycolysis. To understand if this is beneficial or detrimental to the heart, we chronically elevated glycolysis by cardiac-specific overexpression of phosphatase-deficient 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2) in transgenic mice. PFK-2 controls the level of fructose-2,6-bisphosphate (Fru-2,6-P2), an important regulator of phosphofructokinase and glycolysis.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
December 2006
3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors increase endothelial nitric oxide synthase (eNOS) activity by multiple mechanisms. We previously reported that genetic overexpression of eNOS improves survival and cardiac function in congestive heart failure (CHF). In the present study, we tested the hypothesis that low-dose treatment with an 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor exerts beneficial effects on survival and/or cardiac function in a murine model of CHF.
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