Life Sciences Commons^™

Methylglyoxal Requires Ac1 And Trpa1 To Produce Pain And Spinal Neuron Activation, Ryan B. Griggs, Don E. Laird, Renee R. Donahue, Weisi Fu, Bradley K. Taylor

Physiology Faculty Publications

Methylglyoxal (MG) is a metabolite of glucose that may contribute to peripheral neuropathy and pain in diabetic patients. MG increases intracellular calcium in sensory neurons and produces behavioral nociception via the cation channel transient receptor potential ankyrin 1 (TRPA1). However, rigorous characterization of an animal model of methylglyoxal-evoked pain is needed, including testing whether methylglyoxal promotes negative pain affect. Furthermore, it remains unknown whether methylglyoxal is sufficient to activate neurons in the spinal cord dorsal horn, whether this requires TRPA1, and if the calcium-sensitive adenylyl cyclase 1 isoform (AC1) contributes to MG-evoked pain. We administered intraplantar methylglyoxal and then evaluated …

Sustained Sensitizing Effects Of Tumor Necrosis Factor Alpha On Sensory Nerves In Lung And Airways, Ruei-Lung Lin, Qihai Gu, Mehdi Khosravi, Lu-Yuan Lee

Physiology Faculty Publications

Tumor necrosis factor alpha (TNFα) plays a significant role in the pathogenesis of airway inflammatory diseases. Inhalation of aerosolized TNFα induced airway hyperresponsiveness accompanied by airway inflammation in healthy human subjects, but the underlying mechanism is not fully understood. We recently reported a series of studies aimed to investigate if TNFα elevates the sensitivity of vagal bronchopulmonary sensory nerves in a mouse model; these studies are summarized in this mini-review. Our results showed that intratracheal instillation of TNFα induced pronounced airway inflammation 24 hours later, as illustrated by infiltration of eosinophils and neutrophils and the release of inflammatory mediators and …

Abnormal Contractility In Human Heart Myofibrils From Patients With Dilated Cardiomyopathy Due To Mutations In Ttn And Contractile Protein Genes, Petr G. Vikhorev, Natalia Smoktunowicz, Alex B. Munster, O'Neal Copeland, Sawa Kostin, Cecile Montgiraud, Andrew E. Messer, Mohammad R. Toliat, Amy Li, Cristobal G. Dos Remedios, Sean Lal, Cheavar A. Blair, Kenneth S. Campbell, Maya E. Guglin, Ralph Knoll, Steven B. Marston

Physiology Faculty Publications

Dilated cardiomyopathy (DCM) is an important cause of heart failure. Single gene mutations in at least 50 genes have been proposed to account for 25–50% of DCM cases and up to 25% of inherited DCM has been attributed to truncating mutations in the sarcomeric structural protein titin (TTNtv). Whilst the primary molecular mechanism of some DCM-associated mutations in the contractile apparatus has been studied in vitro and in transgenic mice, the contractile defect in human heart muscle has not been studied. In this study we isolated cardiac myofibrils from 3 TTNtv mutants, and 3 with contractile protein mutations (TNNI3 …

Functional Neuroplasticity In The Nucleus Tractus Solitarius And Increased Risk Of Sudden Death In Mice With Acquired Temporal Lobe Epilepsy, Isabel D. Derera, Brian P. Delisle, Bret N. Smith

Physiology Faculty Publications

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in individuals with refractory acquired epilepsy. Cardiorespiratory failure is the most likely cause in most cases, and central autonomic dysfunction has been implicated as a contributing factor to SUDEP. Neurons of the nucleus tractus solitarius (NTS) in the brainstem vagal complex receive and integrate vagally mediated information regarding cardiorespiratory and other autonomic functions, and GABAergic inhibitory NTS neurons play an essential role in modulating autonomic output. We assessed the activity of GABAergic NTS neurons as a function of epilepsy development in the pilocarpine-induced status epilepticus (SE) model of …

No Difference In Myosin Kinetics And Spatial Distribution Of The Lever Arm In The Left And Right Ventricles Of Human Hearts, Divya Duggal, S. Requena, Janhavi Nagwekar, Sangram Raut, Ryan Rich, Hriday Das, Vipul Patel, Ignacy Gryczynski, Rafal Fudala, Zygmunt Gryczynski, Cheavar Blair, Kenneth S. Campbell, Julian Borejdo

Physiology Faculty Publications

The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. …

Nutrients, Infectious And Inflammatory Diseases, Helieh S. Oz

Physiology Faculty Publications

No abstract provided.

Intrathecal Administration Of Ayx2 Dna Decoy Produces A Long-Term Pain Treatment In Rat Models Of Chronic Pain By Inhibiting The Klf6, Klf9, And Klf15 Transcription Factors, Julien Mamet, Michael Klukinov, Scott Harris, Donald C. Manning, Simon Xie, Conrado Pascual, Bradley K. Taylor, Renee R. Donahue, David C. Yeomans

Physiology Faculty Publications

Background: Nociception is maintained by genome-wide regulation of transcription in the dorsal root ganglia—spinal cord network. Hence, transcription factors constitute a promising class of targets for breakthrough pharmacological interventions to treat chronic pain. DNA decoys are oligonucleotides and specific inhibitors of transcription factor activities. A methodological series of in vivo–in vitro screening cycles was performed with decoy/transcription factor couples to identify targets capable of producing a robust and long-lasting inhibition of established chronic pain. Decoys were injected intrathecally and their efficacy was tested in the spared nerve injury and chronic constriction injury models of chronic pain in rats using repetitive …

Brain Injury-Induced Synaptic Reorganization In Hilar Inhibitory Neurons Is Differentially Suppressed By Rapamycin, Corwin R. Butler, Jeffery A. Boychuk, Bret N. Smith

Physiology Faculty Publications

Following traumatic brain injury (TBI), treatment with rapamycin suppresses mammalian (mechanistic) target of rapamycin (mTOR) activity and specific components of hippocampal synaptic reorganization associated with altered cortical excitability and seizure susceptibility. Reemergence of seizures after cessation of rapamycin treatment suggests, however, an incomplete suppression of epileptogenesis. Hilar inhibitory interneurons regulate dentate granule cell (DGC) activity, and de novo synaptic input from both DGCs and CA3 pyramidal cells after TBI increases their excitability but effects of rapamycin treatment on the injury-induced plasticity of interneurons is only partially described. Using transgenic mice in which enhanced green fluorescent protein (eGFP) is expressed in …

Stress Increases Peripheral Axon Growth And Regeneration Through Glucocorticoid Receptor-Dependent Transcriptional Programs, Jessica K. Lerch, Jessica K. Alexander, Kathryn M. Madalena, Dario Motti, Tam Quach, Akhil Dhamija, Alicia Zha, John C. Gensel, Jeanette Webster Marketon, Vance P. Lemmon, John L. Bixby, Phillip G. Popovich

Physiology Faculty Publications

Stress and glucocorticoid (GC) release are common behavioral and hormonal responses to injury or disease. In the brain, stress/GCs can alter neuron structure and function leading to cognitive impairment. Stress and GCs also exacerbate pain, but whether a corresponding change occurs in structural plasticity of sensory neurons is unknown. Here, we show that in female mice (Mus musculus) basal GC receptor (Nr3c1, also known as GR) expression in dorsal root ganglion (DRG) sensory neurons is 15-fold higher than in neurons in canonical stress-responsive brain regions (M. musculus). In response to stress or GCs, adult …

Comparison Of Efficacy And Safety Between First And Second Generation Drug-Eluting Stents In Patients With Stable Coronary Artery Disease: A Single-Center Retrospective Study, Ru Liu, Fei Xiong, Yuan Wen, Yuan-Liang Ma, Yi Yao, Zhan Gao, Bo Xu, Yue-Jin Yang, Shu-Bin Qiao, Run-Lin Gao, Jin-Qing Yuan

Physiology Faculty Publications

Background: Lots of trials demonstrate that second-generation drug-eluting stents (G2-DES), with their improved properties, offer significantly superior efficacy and safety profiles compared to first generation DES (G1-DES) for patients with coronary artery disease (CAD) receiving percutaneous coronary intervention (PCI). This study aimed to verify the advantage of G2-DES over G1-DES in Chinese patients with stable CAD (SCAD).

Methods: For this retrospective observational analysis, 2709 SCAD patients with either G1-DES (n = 863) or G2-DES (n = 1846) were enrolled consecutively throughout 2013. Propensity score matching (PSM) was applied to control differing baseline factors. Two-year outcomes, including major adverse …

Alzheimer's Disease Genetics And Abca7 Splicing, Jared B. Vasquez, James F. Simpson, Ryan Harpole, Steven Estus

Physiology Faculty Publications

Both common and rare polymorphisms within ABCA7 have been associated with Alzheimer’s disease (AD). In particular, the rare AD associated polymorphism rs200538373 was associated with altered ABCA7 exon 41 splicing and an AD risk odds ratio of ∼1.9. To probe the role of this polymorphism in ABCA7 splicing, we used minigene studies and qPCR of human brain RNA. We report aberrant ABCA7 exon 41 splicing in the brain of a carrier of the rs200538373 minor C allele. Moreover, minigene studies show that rs200538373 acts as a robust functional variant in vitro. Lastly, although the ABCA7 isoform with an extended …

Cib2 Interacts With Tmc1 And Tmc2 And Is Essential For Mechanotransduction In Auditory Hair Cells, Arnaud P. J. Giese, Yi-Quan Tang, Ghanshyam P. Sinha, Michael R. Bowl, Adam C. Goldring, Andrew Parker, Mary J. Freeman, Steve D. M. Brown, Saima Riazuddin, Robert Fettiplace, William R. Schafer, Gregory I. Frolenkov, Zubair M. Ahmed

Physiology Faculty Publications

Inner ear hair cells detect sound through deflection of stereocilia, the microvilli-like projections that are arranged in rows of graded heights. Calcium and integrin-binding protein 2 is essential for hearing and localizes to stereocilia, but its exact function is unknown. Here, we have characterized two mutant mouse lines, one lacking calcium and integrin-binding protein 2 and one carrying a human deafness-related Cib2 mutation, and show that both are deaf and exhibit no mechanotransduction in auditory hair cells, despite the presence of tip links that gate the mechanotransducer channels. In addition, mechanotransducing shorter row stereocilia overgrow in hair cell bundles of …

Hypersensitivity Of Vagal Pulmonary Afferents Induced By Tumor Necrosis Factor Alpha In Mice, Ruei-Lung Lin, Qihai Gu, Lu-Yuan Lee

Physiology Faculty Publications

Tumor necrosis factor alpha (TNFα), a pro-inflammatory cytokine, plays a significant role in the pathogenesis of allergic asthma. Inhalation of TNFα also induces airway hyperresponsiveness in healthy human subjects, and the underlying mechanism is not fully understood. A recent study reported that TNFα caused airway inflammation and a sustained elevation of pulmonary chemoreflex responses in mice, suggesting a possible involvement of heightened sensitivity of vagal pulmonary C-fibers. To investigate this possibility, the present study aimed to investigate the effect of a pretreatment with TNFα on the sensitivity of vagal pulmonary afferents in anesthetized mice. After TNFα (10 μg/ml, 0.03 ml) …

Outcomes Of Spatially Fractionated Radiotherapy (Grid) For Bulky Soft Tissue Sarcomas In A Large Animal Model, Michael W. Nolan, Tracy L. Gieger, Alexander A. Karakashian, Mariana N. Nikolova‑Karakashian, Lysa P. Posner, Donald M. Roback, Judith N. Rivera, Sha Chang

Physiology Faculty Publications

GRID directs alternating regions of high- and low-dose radiation at tumors. A large animal model mimicking the geometries of human treatments is needed to complement existing rodent systems (eg, microbeam) and clarify the physical and biological attributes of GRID. A pilot study was undertaken in pet dogs with spontaneous soft tissue sarcomas to characterize responses to GRID. Subjects were treated with either 20 Gy (3 dogs) or 25 Gy (3 dogs), delivered using 6 MV X-rays and a commercial GRID collimator. Acute toxicity and tumor responses were assessed 2, 4, and 6 weeks later. Acute Radiation Therapy Oncology Group grade …

Disulfide High Mobility Group Box-1 Causes Bladder Pain Through Bladder Toll-Like Receptor 4, Fei Ma, Dimitrios E. Kouzoukas, Katherine L. Meyer-Siegler, Karin N. Westlund, David E. Hunt, Pedro L. Vera

Physiology Faculty Publications

Background: Bladder pain is a prominent symptom in several urological conditions (e.g. infection, painful bladder syndrome/interstitial cystitis, cancer). Understanding the mechanism of bladder pain is important, particularly when the pain is not accompanied by bladder pathology. Stimulation of protease activated receptor 4 (PAR4) in the urothelium results in bladder pain through release of urothelial high mobility group box-1 (HMGB1). HGMB1 has two functionally active redox states (disulfide and all-thiol) and it is not known which form elicits bladder pain. Therefore, we investigated whether intravesical administration of specific HMGB1 redox forms caused abdominal mechanical hypersensitivity, micturition changes, and bladder inflammation in …

Pharmacology, Pharmacokinetics, And Metabolism Of The Dna-Decoy Ayx1 For The Prevention Of Acute And Chronic Post-Surgical Pain, Julien Mamet, Scott Harris, Michael Klukinov, David C. Yeomans, Renee R. Donahue, Bradley K. Taylor, Kelly Eddinger, Tony Yaksh, Donald C. Manning

Physiology Faculty Publications

Background: AYX1 is an unmodified DNA-decoy designed to reduce acute post-surgical pain and its chronification with a single intrathecal dose at the time of surgery. AYX1 inhibits the transcription factor early growth response protein 1, which is transiently induced at the time of injury and triggers gene regulation in the dorsal root ganglia and spinal cord that leads to long-term sensitization and pain. This work characterizes the AYX1 dose-response profile in rats and the link to AYX1 pharmacokinetics and metabolism in the cerebrospinal fluid, dorsal root ganglia, and spinal cord.

Results: The effects of ascending dose-levels of AYX1 on mechanical …

Apolipoprotein E4 And Insulin Resistance Interact To Impair Cognition And Alter The Epigenome And Metabolome, Lance A. Johnson, Eileen Ruth S. Torres, Soren Impey, Jan F. Stevens, Jacob Raber

Physiology Faculty Publications

Apolipoprotein E4 (E4) and type 2 diabetes are major risk factors for cognitive decline and late onset Alzheimer’s disease (AD). E4-associated phenotypes and insulin resistance (IR) share several features and appear to interact in driving cognitive dysfunction. However, shared mechanisms that could explain their overlapping pathophysiology have yet to be found. We hypothesized that, compared to E3 mice, E4 mice would be more susceptible to the harmful cognitive effects of high fat diet (HFD)-induced IR due to apoE isoform-specific differences in brain metabolism. While both E3 and E4 mice fed HFD displayed impairments in peripheral metabolism and cognition, deficits in …

Reduced Skeletal Muscle Satellite Cell Number Alters Muscle Morphology After Chronic Stretch But Allows Limited Serial Sarcomere Addition, Matthew C. Kinney, Sudarshan Dayanidhi, Peter B. Dykstra, John J. Mccarthy, Charlotte A. Peterson, Richard L. Lieber

Physiology Faculty Publications

Introduction: Muscles add sarcomeres in response to stretch, presumably to maintain optimal sarcomere length. Clinical evidence from patients with cerebral palsy, who have both decreased serial sarcomere number and reduced satellite cells (SCs), suggests a hypothesis that SCs may be involved in sarcomere addition. Methods: A transgenic Pax7‐DTA mouse model underwent conditional SC depletion, and their soleii were then stretch‐immobilized to assess the capacity for sarcomere addition. Muscle architecture, morphology, and extracellular matrix (ECM) changes were also evaluated. Results: Mice in the SC‐reduced group achieved normal serial sarcomere addition in response to stretch. However, muscle fiber cross‐sectional …

Myocardial Relaxation Is Accelerated By Fast Stretch, Not Reduced Afterload, Charles S. Chung, Charles W. Hoopes, Kenneth S. Campbell

Physiology Faculty Publications

Fast relaxation of cross-bridge generated force in the myocardium facilitates efficient diastolic function. Recently published research studying mechanisms that modulate the relaxation rate has focused on molecular factors. Mechanical factors have received less attention since the 1980s when seminal work established the theory that reducing afterload accelerates the relaxation rate. Clinical trials using afterload reducing drugs, partially based on this theory, have thus far failed to improve outcomes for patients with diastolic dysfunction. Therefore, we reevaluated the protocols that suggest reducing afterload accelerates the relaxation rate and identified that myocardial relengthening was a potential confounding factor. We hypothesized that the …

Transforming Growth Factor-Β In Thoracic Aortic Aneurysms: Good, Bad, Or Irrelevant?, Alan Daugherty, Zheying Chen, Hisashi Sawada, Debra L. Rateri, Mary B. Sheppard

Physiology Faculty Publications

No abstract provided.

Novel Interconnections In Lipid Metabolism Revealed By Overexpression Of Sphingomyelin Synthase-1, Gergana M. Deevska, Patrick P. Dotson Ii, Alexander A. Karakashian, Giorgis Isaac, Mark Wrona, Samuel B. Kelly, Alfred H. Merrill Jr., Mariana N. Nikolova‑Karakashian

Physiology Faculty Publications

This study investigates the consequences of elevating sphingomyelin synthase 1 (SMS1) activity, which generates the main mammalian sphingolipid, sphingomyelin. HepG2 cells stably transfected with SMS1 (HepG2-SMS1) exhibit elevated enzyme activity in vitro and increased sphingomyelin content (mainly C22:0- and C24:0-sphingomyelin) but lower hexosylceramide (Hex-Cer) levels. HepG2-SMS1 cells have fewer triacylglycerols than controls but similar diacylglycerol acyltransferase activity, triacylglycerol secretion, and mitochondrial function. Treatment with 1 mm palmitate increases de novo ceramide synthesis in both cell lines to a similar degree, causing accumulation of C16:0-ceramide (and some C18:0-, C20:0-, and C22:0-ceramides) as well as C16:0- and C18:0-Hex-Cers. In these experiments, the …

Omecamtiv Mecarbil Enhances The Duty Ratio Of Human Β-Cardiac Myosin Resulting In Increased Calcium Sensitivity And Slowed Force Development In Cardiac Muscle, Anja M. Swenson, Wanjian Tang, Cheavar A. Blair, Christopher M. Fetrow, William C. Unrath, Michael J. Previs, Kenneth S. Campbell, Christopher M. Yengo

Physiology Faculty Publications

The small molecule drug omecamtiv mecarbil (OM) specifically targets cardiac muscle myosin and is known to enhance cardiac muscle performance, yet its impact on human cardiac myosin motor function is unclear. We expressed and purified human β-cardiac myosin subfragment 1 (M2β-S1) containing a C-terminal Avi tag. We demonstrate that the maximum actin-activated ATPase activity of M2β-S1 is slowed more than 4-fold in the presence of OM, whereas the actin concentration required for half-maximal ATPase was reduced dramatically (30-fold). We find OM does not change the overall actin affinity. Transient kinetic experiments suggest that there are …

Diaphragm Abnormalities In Patients With End-Stage Heart Failure: Nadph Oxidase Upregulation And Protein Oxidation, Bumsoo Ahn, Philip D. Coblentz, Adam W. Beharry, Nikhil Patel, Andrew R. Judge, Jennifer S. Moylan, Charles W. Hoopes, Mark R. Bonnell, Leonardo F. Ferreira

Physiology Faculty Publications

Patients with heart failure (HF) have diaphragm abnormalities that contribute to disease morbidity and mortality. Studies in animals suggest that reactive oxygen species (ROS) cause diaphragm abnormalities in HF. However, the effects of HF on ROS sources, antioxidant enzymes, and protein oxidation in the diaphragm of humans is unknown. NAD(P)H oxidase, especially the Nox2 isoform, is an important source of ROS in the diaphragm. Our main hypothesis was that diaphragm from patients with HF have heightened Nox2 expression and p47^phox phosphorylation (marker of enzyme activation) that is associated with elevated protein oxidation. We collected diaphragm biopsies from patients with …

Modulating Beta-Cardiac Myosin Function At The Molecular And Tissue Levels, Wanjian Tang, Cheavar A. Blair, Shane D. Walton, András Málnási-Csizmadia, Kenneth S. Campbell, Christopher M. Yengo

Physiology Faculty Publications

Inherited cardiomyopathies are a common form of heart disease that are caused by mutations in sarcomeric proteins with beta cardiac myosin (MYH7) being one of the most frequently affected genes. Since the discovery of the first cardiomyopathy associated mutation in beta-cardiac myosin, a major goal has been to correlate the in vitro myosin motor properties with the contractile performance of cardiac muscle. There has been substantial progress in developing assays to measure the force and velocity properties of purified cardiac muscle myosin but it is still challenging to correlate results from molecular and tissue-level experiments. Mutations that cause …