Helen Elizabeth Collins

University of Louisville | UL · School of Medicine

Purpose of Review Pregnancy and exercise are systemic stressors that promote physiological growth of the heart in response to repetitive volume overload and maintenance of cardiac output. This type of remodeling is distinct from pathological hypertrophy and involves different metabolic mechanisms that facilitate growth; however, it remains unclear...

Autophagy is important for protein and organelle quality control. Growing evidence demonstrates that autophagy is tightly controlled by transcriptional mechanisms, including repression by zinc finger containing KRAB and SCAN domains 3 (ZKSCAN3). We hypothesize that cardiomyocyte-specific ZKSCAN3 knockout (Z3K) disrupts autophagy activation and repr...

During pregnancy, the maternal heart undergoes physiologic growth, which reverses following parturition and is associated with the restoration of hemodynamic parameters. However, the molecular processes underlying the reversal of pregnancy-induced cardiac growth and the time frame in which these changes occur remain unclear. Because changes in card...

Although the structural and functional effects of exercise on the heart are well established, the metabolic changes that occur in the heart during and after exercise remain unclear. In this study, we used metabolomics to assess time-dependent changes in the murine cardiac metabolome following 1 session of treadmill exercise. After the exercise bout...

The goal of this study was to develop an atlas of the metabolic, transcriptional, and proteomic changes that occur with pregnancy in the maternal heart. Timed pregnancy studies in FVB/NJ mice revealed significant increases in heart size by day 8 of pregnancy (mid-pregnancy; MP), which was sustained throughout the rest of the term compared with non-...

Tight spatiotemporal regulation of intracellular Ca2+ plays a critical role in regulating diverse cellular functions including cell survival, metabolism, and transcription. As a result, eukaryotic cells have developed a wide variety of mechanisms for controlling Ca2+ influx and efflux across the plasma membrane as well as Ca2+ release and uptake fr...

Stromal interaction molecule 1 (STIM1) is a major regulator of store-operated calcium entry in non-excitable cells. Recent studies have suggested that STIM1 plays a role in pathological hypertrophy; however, the physiological role of STIM1 in the heart is not well understood. We have shown that mice with a cardiomyocyte deletion of STIM1 (cr STIM1-...

The modification of proteins by O-linked β- N -acetylglucosamine (O-GlcNAc) is associated with the regulation of numerous cellular processes. Despite the importance of O-GlcNAc in mediating cellular function our understanding of the mechanisms that regulate O-GlcNAc levels is limited. One factor known to regulate protein O-GlcNAc levels is nutrient...

Transmission electron microscopy (TEM) has long been an important technique, capable of high degree resolution and visualization of subcellular structures and organization. Over the last 20 years, TEM has gained popularity in the cardiovascular field to visualize changes at the nanometer scale in cardiac ultrastructure during cardiovascular develop...

Cardiovascular disease is the leading cause of death in pregnant and postpartum women. During pregnancy, the maternal heart rapidly adapts to the increasing physiological and metabolic demands of the growing fetus. This adaptation often takes the form of a physiological hypertrophy in which the maternal heart grows to increase cardiac output; howev...

The post-translational modification of serine and threonine residues of nuclear, cytosolic, and mitochondrial proteins by O-linked β-N-acetyl glucosamine (O-GlcNAc) has long been seen as an important regulatory mechanism in the cardiovascular system. O-GlcNAcylation of cardiac proteins has been shown to contribute to the regulation of transcription...

The attachment of O-linked β-N-acetylglucosamine (O-GlcNAc) to the serine and threonine residues of proteins in distinct cellular compartments is increasingly recognized as an important mechanism regulating cellular function. Importantly, the O-GlcNAc modification of mitochondrial proteins has been identified as a potential mechanism to modulate me...

The endoplasmic reticulum/sarcoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1), a key mediator of store-operated Ca2+ entry, is expressed in cardiomyocytes and has been implicated in regulating multiple cardiac processes, including hypertrophic signaling. Interestingly, cardiomyocyte-restricted deletion of STIM1 (crSTIM1-KO) re...

Recent studies suggest that the time of day at which food is consumed dramatically influences clinically-relevant cardiometabolic parameters (e.g., adiposity, insulin sensitivity, and cardiac function). Meal feeding benefits may be the result of daily periods of feeding and/or fasting, highlighting the need for improved understanding of the tempora...

The post-translational modification of serine and threonine residues of proteins found in numerous subcellular locations by O-linked N-acetylglucosamine (O-GlcNAc) is emerging as a key mediator of many cardiovascular pathophysiological processes. Early studies implicated increased protein O-GlcNAcylation as contributing to the cardiovascular compli...

The ER/SR Ca ²⁺ sensor, Stromal Interaction molecule 1 (STIM1), a key regulator of store-operated calcium entry is expressed in cardiomyocytes and has been implicated in regulating hypertrophic signaling. We have recently shown that mice with a cardiomyocyte-restricted deletion of STIM1 develop dilated cardiomyopathy. Given the importance of Ca ²⁺...

Our understanding of the role of protein O-GlcNAcylation in the regulation of the cardiovascular system has increased rapidly in recent years. Studies have linked increased O-GlcNAc levels to glucose toxicity and diabetic complications; conversely, acute activation of O-GlcNAcylation has been shown to be cardioprotective. However, it is also increa...

This editorial refers to ‘Emergence of Orai3 activity during cardiac hypertrophy’ by Y. Saliba et al. , doi:10.1093/cvr/cvu207 . Our understanding of cardiomyocyte Ca2+ handling is primarily based on the regulation of voltage-gated Ca2+ entry, via L-type Ca2+ channels (LTCCs), and the resulting Ca2+-induced Ca2+ release from the sarcoplasmic retic...

Circadian clocks are cell autonomous, transcriptionally based, molecular mechanisms that confer the selective advantage of anticipation, enabling cells/organs to respond to environmental factors in a temporally appropriate manner. Critical to circadian clock function are 2 transcription factors, CLOCK and BMAL1. The purpose of the present study was...

The endoplasmic reticulum (ER) Ca(2+) sensor, stromal interaction molecule 1 (STIM1), has been implicated as a key mediator of store-dependent and store-independent Ca(2+) entry (SOCE) pathways, and maintenance of ER structure. STIM1 is present in embryonic, neonatal and adult cardiomyocytes and has been strongly implicated in hypertrophic signalin...

Store-operated Ca(2+) entry (SOCE) is critical for Ca(2+) signaling in non-excitable cells; however, its role in the regulation of cardiomyocyte Ca(2+) homeostasis has only recently been investigated. The increased understanding of the role of Stromal Interaction Molecule 1 (STIM1) in regulating SOCE combined with recent studies demonstrating the p...

: Excitation-contraction coupling of the normotensive rat heart exhibits a time-of-day variation in its response to isoproterenol (ISO), with a decrease during the animal's active period. Pressure-induced hypertrophy is known to adversely affect the circadian clock in the heart and this study sets out to determine whether this alters the time-of-da...

The innervation of the mouse internal anal sphincter (IAS) has been little studied, and how it changes during aging has not previously been investigated. The aim of this study was therefore to characterize the distribution and density of subtypes of nerve fibers in the IAS and underlying mucosa in 3-, 12- to 13-, 18- and 24- to 25-month-old male C5...

Although >10% of cardiac gene expression displays diurnal variations, little is known of their impact on excitation-contraction coupling. To determine whether the time of day affects excitation-contraction coupling in rat ventricles. Left ventricular myocytes were isolated from rat hearts at 2 opposing time points, corresponding to the animals rest...