Physiology Commons^™

Chronic Muscle Weakness And Mitochondrial Dysfunction In The Absence Of Sustained Atrophy In A Preclinical Sepsis Model, Allison M. Owen, Samir P. Patel, Jeffrey D. Smith, Beverly K. Balasuriya, Stephanie F. Mori, Gregory S. Hawk, Arnold J. Stromberg, Naohide Kuriyama, Masao Kaneki, Alexander G. Rabchevsky, Timothy A. Butterfield, Karyn A. Esser, Charlotte A. Peterson, Marlene E. Starr, Hiroshi Saito

Physiology Faculty Publications

Chronic critical illness is a global clinical issue affecting millions of sepsis survivors annually. Survivors report chronic skeletal muscle weakness and development of new functional limitations that persist for years. To delineate mechanisms of sepsis-induced chronic weakness, we first surpassed a critical barrier by establishing a murine model of sepsis with ICU-like interventions that allows for the study of survivors. We show that sepsis survivors have profound weakness for at least 1 month, even after recovery of muscle mass. Abnormal mitochondrial ultrastructure, impaired respiration and electron transport chain activities, and persistent protein oxidative damage were evident in the muscle of …

Targeted Limb Heating Augments The Actions Of Igf1 In The Growth Plate And Increases Bone Elongation In Growing Mice, Holly Lyn Racine

Theses, Dissertations and Capstones

Bone elongation disorders can lead to painful musculoskeletal disabilities in adulthood. Existing treatment options to correct left-right asymmetry in limb length include invasive surgeries and/or drug regimens. These are often only partially effective. Previous studies in weanling mice have shown that a daily application of mild heat (40°C) to limbs on one side of the body could be used to noninvasively enhance bone elongation. However, the impact of heat-treatment on bone at the cellular level remains elusive. The epiphyseal growth plate, the band of cartilage located at each end of long bones, is the main site of longitudinal growth and …

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 …

Inhibition Of Post-Transcriptional Steps In Ribosome Biogenesis Confers Cytoprotection Against Chemotherapeutic Agents In A P53-Dependent Manner, Russell T Sapio, Anastasiya N Nezdyur, Matthew Krevetski, Leonid Anikin, Vincent J Manna, Natalie Minkovsky, Dimitri G Pestov

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

The p53-mediated nucleolar stress response associated with inhibition of ribosomal RNA transcription was previously shown to potentiate killing of tumor cells. Here, we asked whether targeting of ribosome biogenesis can be used as the basis for selective p53-dependent cytoprotection of nonmalignant cells. Temporary functional inactivation of the 60S ribosome assembly factor Bop1 in a 3T3 cell model markedly increased cell recovery after exposure to camptothecin or methotrexate. This was due, at least in part, to reversible pausing of the cell cycle preventing S phase associated DNA damage. Similar cytoprotective effects were observed after transient shRNA-mediated silencing of Rps19, but not …

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) …

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 …

Development Of Activity In The Mouse Visual Cortex., Jing Shen, Matthew T Colonnese

Pharmacology and Physiology Faculty Publications

No abstract provided.

Repeated Closed Head Injury In Mice Results In Sustained Motor And Memory Deficits And Chronic Cellular Changes, Amanda Nicholle Bolton Hall, Binoy Joseph, Jennifer M. Brelsfoard, Kathryn E. Saatman

Spinal Cord and Brain Injury Research Center Faculty Publications

Millions of mild traumatic brain injuries (TBIs) occur every year in the United States, with many people subject to multiple head injuries that can lead to chronic behavioral dysfunction. We previously reported that mild TBI induced using closed head injuries (CHI) repeated at 24h intervals produced more acute neuron death and glial reactivity than a single CHI, and increasing the length of time between injuries to 48h reduced the cumulative acute effects of repeated CHI. To determine whether repeated CHI is associated with behavioral dysfunction or persistent cellular damage, mice receiving either five CHI at 24h intervals, five CHI at …

Myonuclear Transcription Is Responsive To Mechanical Load And Dna Content But Uncoupled From Cell Size During Hypertrophy, Tyler J. Kirby, Rooshil M. Patel, Timothy S. Mcclintock, Esther E. Dupont-Versteegden, Charlotte A. Peterson, John J. Mccarthy

Physiology Faculty Publications

Myofibers increase size and DNA content in response to a hypertrophic stimulus, thus providing a physiological model with which to study how these factors affect global transcription. Using 5-ethynyl uridine (EU) to metabolically label nascent RNA, we measured a sevenfold increase in myofiber transcription during early hypertrophy before a change in cell size and DNA content. The typical increase in myofiber DNA content observed at the later stage of hypertrophy was associated with a significant decrease in the percentage of EU-positive myonuclei; however, when DNA content was held constant by preventing myonuclear accretion via satellite cell depletion, both the number …

Mw151 Inhibited Il-1Β Levels After Traumatic Brain Injury With No Effect On Microglia Physiological Responses, Adam D. Bachstetter, Zhengqiu Zhou, Rachel K. Rowe, Bin Xing, Danielle S. Goulding, Alyssa N. Conley, Pradoldej Sompol, Shelby Meier, Jose F. Abisambra, Jonathan Lifshitz, D. Martin Watterson, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

A prevailing neuroinflammation hypothesis is that increased production of proinflammatory cytokines contributes to progressive neuropathology, secondary to the primary damage caused by a traumatic brain injury (TBI). In support of the hypothesis, post-injury interventions that inhibit the proinflammatory cytokine surge can attenuate the progressive pathology. However, other post-injury neuroinflammatory responses are key to endogenous recovery responses. Therefore, it is critical that pharmacological attenuation of detrimental or dysregulated neuroinflammatory processes avoid pan-suppression of inflammation. MW151 is a CNS-penetrant, small molecule experimental therapeutic that restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis without immunosuppression. Post-injury administration of MW151 in a …

Serum Amyloid A Impairs The Antiinflammatory Properties Of Hdl, Chang Yeop Han, Chongren Tang, Myriam E. Guevara, Hao Wei, Tomasz Wietecha, Baohai Shao, Savitha Subramanian, Mohamed Omer, Shari Wang, Kevin D. O'Brien, Santica M. Marcovina, Thomas N. Wight, Tomas Vaisar, Maria C. De Beer, Frederick C. De Beer, William R. Osborne, Keith B. Elkon, Alan Chait

Physiology Faculty Publications

HDL from healthy humans and lean mice inhibits palmitate-induced adipocyte inflammation; however, the effect of the inflammatory state on the functional properties of HDL on adipocytes is unknown. Here, we found that HDL from mice injected with AgNO₃ fails to inhibit palmitate-induced inflammation and reduces cholesterol efflux from 3T3-L1 adipocytes. Moreover, HDL isolated from obese mice with moderate inflammation and humans with systemic lupus erythematosus had similar effects. Since serum amyloid A (SAA) concentrations in HDL increase with inflammation, we investigated whether elevated SAA is a causal factor in HDL dysfunction. HDL from AgNO₃-injected mice lacking Saa1.1 …

Characterization Of Secretory Sphingomyelinase Activity, Lipoprotein Sphingolipid Content And Ldl Aggregation In Ldlr-/- Mice Fed On A High-Fat Diet, Gergana M. Deevska, Manjula Sunkara, Andrew J. Morris, Mariana N. Nikolova‑Karakashian

Physiology Faculty Publications

The propensity of LDLs (low-density lipoproteins) for aggregation and/or oxidation has been linked to their sphingolipid content, specifically the levels of SM (sphingomyelin) and ceramide. To investigate this association in vivo, ldlr (LDL receptor)-null mice (ldlr-/-) were fed on a modified (atherogenic) diet containing saturated fats and cholesterol. The diet led to significantly elevated SM content in all serum lipoproteins. In contrast, ceramide increased only in the LDL particles. MS-based analyses of the lipid acyl chain composition revealed a marked elevation in C16:0 fatty acid in SM and ceramide, consistent with the prevalence of palmitic acid in the modified diet. …

Atovaquone Ameliorate Gastrointestinal Toxoplasmosis Complications In A Pregnancy Model, Helieh S. Oz, Thomas Tobin

Physiology Faculty Publications

Background: Toxoplasma is an important source of foodborne hospitalization with no safe and effective therapy against chronic or congenital Toxopalsmosis. Atovaquone is a drug of choice but not approved for use in congenital Toxoplasmosis. We hypothesized atovaquone to be safe and effective against feto-maternal Toxoplasmosis.

Material/Methods: Programmed pregnant mice were i.p. infected with 50–2400 Tachyzoites from Type II strain (clone PTG). Dams were treated daily with atovaquone or sham and monitored for pain, and complications.

Results: Dams developed pain related abdominal hypersensitivity (allodynia) to mechanical stimuli in a Tachyzoites dose dependent manner. Infected dams were anemic and exhibited ascities and …

Early Stage Drug Treatment That Normalizes Proinflammatory Cytokine Production Attenuates Synaptic Dysfunction In A Mouse Model That Exhibits Age-Dependent Progression Of Alzheimer's Disease-Related Pathology, Adam D. Bachstetter, Christopher M. Norris, Pradoldej Sompol, Donna M. Wilcock, Danielle Goulding, Janna H. Neltner, Daret St. Clair, D. Martin Watterson, Linda J. Van Eldik

Sanders-Brown Center on Aging Faculty Publications

Overproduction of proinflammatory cytokines in the CNS has been implicated as a key contributor to pathophysiology progression in Alzheimer's disease (AD), and extensive studies with animal models have shown that selective suppression of excessive glial proinflammatory cytokines can improve neurologic outcomes. The prior art, therefore, raises the logical postulation that intervention with drugs targeting dysregulated glial proinflammatory cytokine production might be effective disease-modifying therapeutics if used in the appropriate biological time window. To test the hypothesis that early stage intervention with such drugs might be therapeutically beneficial, we examined the impact of intervention with MW01-2-151SRM (MW-151), an experimental therapeutic that …

Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay

Physiology Faculty Publications

AIMS AND HYPOTHESIS: Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo.

METHODS: Gem-deficient mice were generated and their metabolic phenotype characterised by in …

Functional Plasticity Of Central Trpv1 Receptors In Brainstem Dorsal Vagal Complex Circuits Of Streptozotocin-Treated Hyperglycemic Mice, Andrea Zsombok, Muthu D. Bhaskaran, Hong Gao, Andrei V. Derbenev, Bret N. Smith

Physiology Faculty Publications

Emerging data indicate that central neurons participate in diabetic processes by modulating autonomic output from neurons in the dorsal motor nucleus of the vagus (DMV). We tested the hypothesis that synaptic modulation by transient receptor potential vanilloid type 1 (TRPV1) receptors is reduced in the DMV in slices from a murine model of type 1 diabetes. The TRPV1 agonist capsaicin robustly enhanced glutamate release onto DMV neurons by acting at preterminal receptors in slices from intact mice, but failed to do so in slices from diabetic mice. TRPV1 receptor protein expression in the vagal complex was unaltered. Brief insulin preapplication …

Association Between Chronic Liver And Colon Inflammation During The Development Of Murine Syngeneic Graft-Versus-Host Disease, Jason Anthony Brandon, Jacqueline Perez-Rodriguez, C. Darrell Jennings, Donald A. Cohen, Vishal J. Sindhava, Subbarao Bondada, Alan M. Kaplan, J. Scott Bryson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The murine model of cyclosporine A (CsA)-induced syngeneic graft-versus-host disease (SGVHD) is a bone marrow (BM) transplantation model that develops chronic colon inflammation identical to other murine models of CD4⁺ T cell-mediated colitis. Interestingly, SGVHD animals develop chronic liver lesions that are similar to the early peribiliary inflammatory stages of clinical chronic liver disease, which is frequently associated with inflammatory bowel disease (IBD). Therefore, studies were initiated to investigate the chronic liver inflammation that develops in the SGVHD model. To induce SGVHD, mice were lethally irradiated, reconstituted with syngeneic BM, and treated with CsA. All of the SGVHD animals …

Impaired Fast-Spiking, Suppressed Cortical Inhibition, And Increased Susceptibility To Seizures In Mice Lacking Kv3.2 K+ Channel Proteins, David Lau, Eleazar Vega-Saenz De Miera, Diego Contreras, Alan Chow, Richard Paylor, Christopher S. Leonard, Bernardo Rudy

NYMC Faculty Publications

Voltage-gated K(+) channels of the Kv3 subfamily have unusual electrophysiological properties, including activation at very depolarized voltages (positive to -10 mV) and very fast deactivation rates, suggesting special roles in neuronal excitability. In the brain, Kv3 channels are prominently expressed in select neuronal populations, which include fast-spiking (FS) GABAergic interneurons of the neocortex, hippocampus, and caudate, as well as other high-frequency firing neurons. Although evidence points to a key role in high-frequency firing, a definitive understanding of the function of these channels has been hampered by a lack of selective pharmacological tools. We therefore generated mouse lines in which one …

Induction Of Integral Membrane Pam Expression In Att-20 Cells Alters The Storage And Trafficking Of Pomc And Pc1, Giuseppe D. Ciccotosto, Martin R. Schiller, Betty A. Eipper, Richard E. Mains

Life Sciences Faculty Research

Peptidylglycine alpha-amidating monooxygenase (PAM) is an essential enzyme that catalyzes the COOH-terminal amidation of many neuroendocrine peptides. The bifunctional PAM protein contains an NH2-terminal monooxygenase (PHM) domain followed by a lyase (PAL) domain and a transmembrane domain. The cytosolic tail of PAM interacts with proteins that can affect cytoskeletal organization. A reverse tetracycline-regulated inducible expression system was used to construct an AtT-20 corticotrope cell line capable of inducible PAM-1 expression. Upon induction, cells displayed a time- and dose-dependent increase in enzyme activity, PAM mRNA, and protein. Induction of increased PAM-1 expression produced graded changes in PAM-1 metabolism. Increased expression of …