Life Sciences Commons^™

Reduced Mitochondrial Dna And Oxphos Protein Content In Skeletal Muscle Of Children With Cerebral Palsy, Ferdinand Von Walden, Ivan J. Vechetti Jr., Davis A. Englund, Vandré C. Figueiredo, Rodrigo Fernandez-Gonzalo, Kevin A. Murach, Jessica Pingel, John J. Mccarthy, Per Stål, Eva Pontén

Physiology Faculty Publications

AIM: To provide a detailed gene and protein expression analysis related to mitochondrial biogenesis and assess mitochondrial content in skeletal muscle of children with cerebral palsy (CP).

METHOD: Biceps brachii muscle samples were collected from 19 children with CP (mean [SD] age 15y 4mo [2y 6mo], range 9-18y, 16 males, three females) and 10 typically developing comparison children (mean [SD] age 15y [4y], range 7-21y, eight males, two females). Gene expression (quantitative reverse transcription polymerase chain reaction [PCR]), mitochondrial DNA (mtDNA) to genomic DNA ratio (quantitative PCR), and protein abundance (western blotting) were analyzed. Microarray data sets (CP/aging/bed rest) were …

Near Simultaneous Laser Scanning Confocal And Atomic Force Microscopy (Conpokal) On Live Cells, Joree N. Sandin, Surya P. Aryal, Thomas E. Wilkop, Christopher I. Richards, Martha E. Grady

Physiology Faculty Publications

Techniques available for micro- and nano-scale mechanical characterization have exploded in the last few decades. From further development of the scanning and transmission electron microscope, to the invention of atomic force microscopy, and advances in fluorescent imaging, there have been substantial gains in technologies that enable the study of small materials. Conpokal is a portmanteau that combines confocal microscopy with atomic force microscopy (AFM), where a probe "pokes" the surface. Although each technique is extremely effective for the qualitative and/or quantitative image collection on their own, Conpokal provides the capability to test with blended fluorescence imaging and mechanical characterization. Designed …

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 …

Macrophage-Derived Netrin-1 Promotes Abdominal Aortic Aneurysm Formation By Activating Mmp3 In Vascular Smooth Muscle Cells, Tarik Hadi, Ludovic Boytard, Michele Silvestro, Dornazsadat Alebrahim, Samson Jacob, Jordyn Feinstein, Krista Barone, Wes Spiro, Susan Hutchison, Russell Simon, Debra L. Rateri, Florence Pinet, David Fenyo, Mark Adelman, Kathryn J. Moore, Holger K. Eltzschig, Alan Daugherty, Bhama Ramkhelawon

Physiology Faculty Publications

Abdominal aortic aneurysms (AAA) are characterized by extensive extracellular matrix (ECM) fragmentation and inflammation. However, the mechanisms by which these events are coupled thereby fueling focal vascular damage are undefined. Here we report through single-cell RNA-sequencing of diseased aorta that the neuronal guidance cue netrin-1 can act at the interface of macrophage-driven injury and ECM degradation. Netrin-1 expression peaks in human and murine aneurysmal macrophages. Targeted deletion of netrin-1 in macrophages protects mice from developing AAA. Through its receptor neogenin-1, netrin-1 induces a robust intracellular calcium flux necessary for the transcriptional regulation and persistent catalytic activation of matrix metalloproteinase-3 (MMP3) …

Autonomic Dysreflexia After Spinal Cord Injury: Systemic Pathophysiology And Methods Of Management, Khalid C. Eldahan, Alexander G. Rabchevsky

Physiology Faculty Publications

Traumatic spinal cord injury (SCI) has widespread physiological effects beyond the disruption of sensory and motor function, notably the loss of normal autonomic and cardiovascular control. Injury at or above the sixth thoracic spinal cord segment segregates critical spinal sympathetic neurons from supraspinal modulation which can result in a syndrome known as autonomic dysreflexia (AD). AD is defined as episodic hypertension and concomitant baroreflex-mediated bradycardia initiated by unmodulated sympathetic reflexes in the decentralized cord. This condition is often triggered by noxious yet unperceived visceral or somatic stimuli below the injury level and if severe enough can require immediate medical attention. …

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 …

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 …

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 …

Effects Of Target-Controlled Infusion Of High-Dose Naloxone On Pain And Hyperalgesia In A Human Thermal Injury Model: A Study Protocol, Anders D. Springborg, Elisabeth K. Jensen, Bradley K. Taylor, Mads U. Werner

Physiology Faculty Publications

Mu-opioid-receptor antagonists have been extensively studied in experimental research as pharmacological tools uncovering mechanisms of pain modulation by the endogenous opioid system. In rodents, administration of high doses of mu-opioid-receptor antagonists after the resolution of an inflammatory injury has demonstrated reinstatement of nociceptive hypersensitivity indicating unmasking of latent sensitization. In a recent human study, pain hypersensitivity assessed as secondary hyperalgesia area (SHA), was reinstated 7 days after a mild thermal injury, in 4 out of 12 subjects after a naloxone infusion.

The aims of the present study are first, to replicate our previous findings in a larger-sized study; second, to …

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

Physiology Faculty Publications

Pain is the significant presenting symptom in Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS). Activation of urothelial protease activated receptor 4 (PAR4) causes pain through release of urothelial macrophage migration inhibitory factor (MIF). High Mobility Group Box-1 (HMGB1), a chromatin-binding protein, mediates bladder pain (but not inflammation) in an experimental model (cyclophosphamide) of cystitis. To determine if PAR4-induced bladder hypersensitivity depends on HMGB1 downstream, we tested whether: 1) bladder PAR4 stimulation affected urothelial HMGB1 release; 2) blocking MIF inhibited urothelial HMGB1 release; and 3) blocking HMGB1 prevented PAR4-induced bladder hypersensitivity. HMGB1 release was examined in immortalized human urothelial cultures (UROtsa) exposed to …

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 …

Macrophage Migration Inhibitory Factor Mediates Par-Induced Bladder Pain., Dimitrios E. Kouzoukas, Katherine L. Meyer-Siegler, Fei Ma, Karin N. Westlund, David E. Hunt, Pedro L. Vera

Physiology Faculty Publications

INTRODUCTION: Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine, is constitutively expressed in urothelial cells that also express protease-activated receptors (PAR). Urothelial PAR1 receptors were shown to mediate bladder inflammation. We showed that PAR1 and PAR4 activator, thrombin, also mediates urothelial MIF release. We hypothesized that stimulation of urothelial PAR1 or PAR4 receptors elicits release of urothelial MIF that acts on MIF receptors in the urothelium to mediate bladder inflammation and pain. Thus, we examined the effect of activation of specific bladder PAR receptors on MIF release, bladder pain, micturition and histological changes.

METHODS: MIF release was measured …

An Intronic Picalm Polymorphism, Rs588076, Is Associated With Allelic Expression Of A Picalm Isoform, Ishita Parikh, Christopher Medway, Steven Younkin, David Fardo, Steven Estus

Physiology Faculty Publications

BACKGROUND: Although genome wide studies have associated single nucleotide polymorphisms (SNP)s near PICALM with Alzheimer's disease (AD), the mechanism underlying this association is unclear. PICALM is involved in clathrin-mediated endocytosis and modulates Aß clearance in vitro. Comparing allelic expression provides the means to detect cis-acting regulatory polymorphisms. Thus, we evaluated whether PICALM showed allele expression imbalance (AEI) and whether this imbalance was associated with the AD-associated polymorphism, rs3851179.

RESULTS: We measured PICALM allelic expression in 42 human brain samples by using next-generation sequencing. Overall, PICALM demonstrated equal allelic expression with no detectable influence by rs3851179. A single sample demonstrated …

Neutral Sphingomyelinase-3 Mediates Tnf-Stimulated Oxidant Activity In Skeletal Muscle, Jennifer S. Moylan, Jeffrey D. Smith, Erin M. Wolf Horrell, Julie B. Mclean, Gergana M. Deevska, Mark R. Bonnell, Mariana N. Nikolova‑Karakashian, Michael B. Reid

Physiology Faculty Publications

AIMS: Sphingolipid and oxidant signaling affect glucose uptake, atrophy, and force production of skeletal muscle similarly and both are stimulated by tumor necrosis factor (TNF), suggesting a connection between systems. Sphingolipid signaling is initiated by neutral sphingomyelinase (nSMase), a family of agonist-activated effector enzymes. Northern blot analyses suggest that nSMase3 may be a striated muscle-specific nSMase. The present study tested the hypothesis that nSMase3 protein is expressed in skeletal muscle and functions to regulate TNF-stimulated oxidant production.

RESULTS: We demonstrate constitutive nSMase activity in skeletal muscles of healthy mice and humans and in differentiated C2C12 myotubes. nSMase3 ( …

Arrhythmogenic Calmodulin Mutations Disrupt Intracellular Cardiomyocyte Ca2+ Regulation By Distinct Mechanisms, Guo Yin, Faisal Hassan, Ayman R. Haroun, Lisa L. Murphy, Lia Crotti, Peter J. Schwartz, Alfred L. George, Jonathan Satin

Physiology Faculty Publications

BACKGROUND: Calmodulin (CaM) mutations have been identified recently in subjects with congenital long QT syndrome (LQTS) or catecholaminergic polymorphic ventricular tachycardia (CPVT), but the mechanisms responsible for these divergent arrhythmia-susceptibility syndromes in this context are unknown. We tested the hypothesis that LQTS-associated CaM mutants disrupt Ca²⁺ homeostasis in developing cardiomyocytes possibly by affecting either late Na current or Ca²⁺-dependent inactivation of L-type Ca²⁺ current.

METHODS AND RESULTS: We coexpressed CaM mutants with the human cardiac Na channel (Na_V1.5) in tsA201 cells, and we used mammalian fetal ventricular cardiomyocytes to investigate LQTS- and CPVT-associated CaM …

Analgesic Tolerance Of Opioid Agonists In Mutant Mu-Opioid Receptors Expressed In Sensory Neurons Following Intrathecal Plasmid Gene Delivery, Guangwen Li, Fei Ma, Yanping Gu, Li-Yen Mae Huang

Physiology Faculty Publications

Background: Phosphorylation sites in the C-terminus of mu-opioid receptors (MORs) are known to play critical roles in the receptor functions. Our understanding of their participation in opioid analgesia is mostly based on studies of opioid effects on mutant receptors expressed in in vitro preparations, including cell lines, isolated neurons and brain slices. The behavioral consequences of the mutation have not been fully explored due to the complexity in studies of mutant receptors in vivo. To facilitate the determination of the contribution of phosphorylation sites in MOR to opioid-induced analgesic behaviors, we expressed mutant and wild-type human MORs (hMORs) in sensory …

Down's Syndrome, Neroinflammation, And Alzheimer Neuropathogenesis, Donna M. Wilcock, W. Sue T. Griffin

Physiology Faculty Publications

Down syndrome (DS) is the result of triplication of chromosome 21 (trisomy 21) and is the prevailing cause of mental retardation. In addition to the mental deficiencies and physical anomalies noted at birth, triplication of chromosome 21 gene products results in the neuropathological and cognitive changes of Alzheimer's disease (AD). Mapping of the gene that encodes the precursor protein (APP) of the β-amyloid (Aβ) present in the Aβ plaques in both AD and DS to chromosome 21 was strong evidence that this chromosome 21 gene product was a principal neuropathogenic culprit in AD as well as DS. The discovery of …

Excitatory Amino Acids Display Compartmental Disparity Between Plasma And Synovial Fluid In Clinical Arthropathies, Terry A. Mcnearney, Karin N. Westlund

Physiology Faculty Publications

BACKGROUND: Previous studies have demonstrated elevated levels of excitatory amino acids (EAA) glutamate (Glu) and aspartate (Asp) in the synovial fluid (SF) of patients with active arthritis. The source of SF EAA concentrations are thought in large part to be secondary to passive diffusion from the plasma across synovial membranes and less so, reflective of local synovial pathology.

OBJECTIVE: This descriptive report assesses the hypothesis that the SF EAA levels reflect inflammatory processes of the joint and are not dependent on plasma levels.

METHODS: Simultaneously drawn plasma and SF samples were obtained from 14 recently deceased cadavers and 10 patients …

Pegylated Arginine Deiminase Downregulates Colitis In Murine Models, Helieh S. Oz, Jian Zhong, Willem J. S. De Villiers

Physiology Faculty Publications

Arginine deiminase (ADI), an arginine-metabolizing enzyme involved in cell signaling, is dysregulated in multiple inflammatory diseases and cancers. We hypothesized that pegylated ADI (ADI-PEG) provide protection against colitis.

METHODS: Dextran sodium sulfate colitis was induced in IL-10-deficient and BALB/c (WT) mice. ADI-PEG was administered i.p., and inflammatory mediators and pathology were evaluated.

RESULTS: Acute colitis in mice was manifested by increases in inflammatory biomarkers, such as serum amyloid A (SAA, P < 0.001), IL-12 p40, and disease index (3-Fold). In contrast, ADI-PEG significantly decreased clinical disease index, SAA levels, and inflammatory cytokines in blood as well as in colonic explants. Animals developed moderate (2.2 ± 0.3 WT) to severe (3.6 ± 0.5 IL-10 deficient) colonic pathology; and ADI-PEG treatment significantly improved the severity of colitis (P < 0.05). Marked infiltration of CD68+ macrophages and iNOS expression were detected in colonic submucosa in colitic animals but not detected in ADI-PEG-treated animals.

CONCLUSION: ADI-PEG attenuated inflammatory responses by suppression of macrophage infiltration and iNOS expression in colitic animals. ADI-PEG can serve as a potential therapeutic value in IBD.

Nutrition, Inflammation, And Infectious Disease, Helieh S. Oz, Sung-Ling Yeh

Physiology Faculty Publications

No abstract provided.

Store-Operated Ca(2+) Entry (Soce) Contributes To Normal Skeletal Muscle Contractility In Young But Not In Aged Skeletal Muscle, Angela M. Thornton, Xiaoli Zhao, Noah Weisleder, Leticia S. Brotto, Sylvain Bougoin, Thomas M. Nosek, Michael B. Reid, Brian Hardin, Zui Pan, Jianjie Ma, Jerome Parness, Marco Brotto

Physiology Faculty Publications

Muscle atrophy alone is insufficient to explain the significant decline in contractile force of skeletal muscle during normal aging. One contributing factor to decreased contractile force in aging skeletal muscle could be compromised excitation-contraction (E-C) coupling, without sufficient available Ca(2+) to allow for repetitive muscle contractility, skeletal muscles naturally become weaker. Using biophysical approaches, we previously showed that store-operated Ca(2+) entry (SOCE) is compromised in aged skeletal muscle but not in young ones. While important, a missing component from previous studies is whether or not SOCE function correlates with contractile function during aging. Here we test the contribution of extracellular …

Mip/Mtmr14 And Muscle Aging, Scott K. Powers, Michael B. Reid

Physiology Faculty Publications

No abstract.

Distorting The Sarcomere, Kenneth S. Campbell

Physiology Faculty Publications

No abstract provided.

Impact Of Central And Peripheral Trpv1 And Ros Levels On Proinflammatory Mediators And Nociceptive Behavior, Karin N. Westlund, Mikhail Y. Kochukov, Ying Lu, Terry A. Mcnearney

Physiology Faculty Publications

Background: Transient receptor potential vanilloid 1 (TRPV1) channels are important membrane sensors on peripheral nerve endings and on supportive non-neuronal synoviocytes in the knee joint. TRPV 1 ion channels respond with activation of calcium and sodium fluxes to pH, thermal, chemical, osmotic, mechanical and other stimuli abundant in inflamed joints. In the present study, the kaolin/carrageenan (k/c) induced knee joint arthritis model in rats, as well as primary and clonal human synoviocyte cultures were used to understand the reciprocal interactions between reactive nitroxidative species (ROS) and functional TRPV1 channels. ROS generation was monitored with ROS sensitive dyes using live cell …

Tumor Necrosis Factor-Alpha (Tnf-Α) Enhances Functional Thermal And Chemical Responses Of Trp Cation Channels In Human Synoviocytes, Mikhail Y. Kochukov, Terry A. Mcnearney, Huaizhi Yin, Liping Zhang, Fei Ma, Larissa Ponomareva, Sarah Abshire, Karin N. Westlund

Physiology Faculty Publications

Background: We have shown functional expression of several TRP channels on human synovial cells, proposing significance in known calcium dependent proliferative and secretory responses in joint inflammation. The present study further characterizes synoviocyte TRP expression and activation responses to thermal and osmotic stimuli after pre-treatment with proinflammatory mediator tumor necrosis factor alpha (TNF-α, EC50 1.3221 x 10^-10 g/L).

Results: Fluorescent imaging of Fura-2 loaded human SW982 synoviocytes reveals immediate and delayed cytosolic calcium oscillations elicited by (1) TRPV1 agonists capsaicin and resiniferatoxin (20-40% of cells), (2) moderate and noxious temperature change, and (3) osmotic stress TRPV4 activation (11.5% of …

The Pulmonary Effects Of Intravenous Adenosine In Asthmatic Subjects, Nausherwan K. Burki, Mahmud Alam, Lu-Yuan Lee

Physiology Faculty Publications

BACKGROUND: We have shown that intravenous adenosine in normal subjects does not cause bronchospasm, but causes dyspnea, most likely by an effect on vagal C fibers in the lungs [Burki et al. J Appl Physiol 2005; 98:180-5]. Since airways inflammation and bronchial hyperreactivity are features of asthma, it is possible that intravenous adenosine may be associated with an increased intensity of dyspnea, and may cause bronchospasm, as noted anecdotally in previous reports.

METHODS: We compared the effects of placebo and 10 mg intravenous adenosine, in 6 normal and 6 asthmatic subjects.

RESULTS: Placebo injection had no significant (p > 0.05) effect …