Medical Physiology Commons^™

Ovarian Tumour Growth Is Characterized By Mevalonate Pathway Gene Signature In An Orthotopic, Syngeneic Model Of Epithelial Ovarian Cancer, Daniel B. Hardy

Physiology and Pharmacology Publications

Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer and often is not detected until late stages when cancer cells transcoelomically metastasize to the abdomen and typically become resistant to therapy resulting in very low survival rates. We utilize an orthotopic, syngeneic mouse model to study late stage disease and have discovered that the tumor cells within the abdominal ascites are irreversibly re-programmed, with an increased tumorigenicity and resistance to apoptosis. The goal of this study was to characterize the reprogramming that occurred in the aggressive ascites-derived cells (28-2 cells) compared to the original cell line used for tumor …

Nicotine Directly Induces Endoplasmic Reticulum Stress Response In Rat Placental Trophoblast Giant Cells, Michael K. Wong, Alison Holloway C, Daniel B. Hardy

Physiology and Pharmacology Publications

Nicotine exposure during pregnancy leads to placental insufficiency impairing both fetal and neonatal development. Previous studies from our laboratory have demonstrated that in rats,nicotine augmented endoplasmic reticulum (ER) stress in association with placental insufficiency, however, the underlying mechanisms remain elusive. Therefore, we sought to investigate the possible direct effect of nicotine on ER stress in Rcho-1 rat placental trophoblastgiant (TG) cells during differentiation. Protein and/or mRNA expression of markers involved in ER stress (e.g., phosphorylated PERK, eIF2α, CHOP, BiP/GRP78) and trophoblast giant cell differentiation and function (e.g., Pl-1, Pgf, Hsd11b1, and Hsd11b2) were quantified via Western blot or …

Micrornas Are Involved In The Development Of Morphine-Induced Analgesic Tolerance And Regulate Functionally Relevant Changes In Serpini1., Jenica D. Tapocik, Kristin Ceniccola, Cheryl L. Mayo, Melanie L. Schwandt, Matthew Solomon, Bi-Dar Wang, Truong V. Luu, Jacqueline Olender, Thomas Harrigan, Thomas M. Maynard, Greg I. Elmer, Norman H. Lee

Pharmacology and Physiology Faculty Publications

Long-term opioid treatment results in reduced therapeutic efficacy and in turn leads to an increase in the dose required to produce equivalent pain relief and alleviate break-through or insurmountable pain. Altered gene expression is a likely means for inducing long-term neuroadaptations responsible for tolerance. Studies conducted by our laboratory (Tapocik et al., 2009) revealed a network of gene expression changes occurring in canonical pathways involved in neuroplasticity, and uncovered miRNA processing as a potential mechanism. In particular, the mRNA coding the protein responsible for processing miRNAs, Dicer1, was positively correlated with the development of analgesic tolerance. The …

Angiotensin Ii-Induced Hypertension Is Attenuated By Overexpressing Copper/Zinc Superoxide Dismutase In The Brain Organum Vasculosum Of The Lamina Terminalis., John P. Collister, Heather Taylor-Smith, Donna Drebes, David Nahey, Jun Tian, Matthew C. Zimmerman

Journal Articles: Cellular & Integrative Physiology

Angiotensin II (AngII) can access the brain via circumventricular organs (CVOs), including the subfornical organ (SFO) and organum vasculosum of the lamina terminalis (OVLT), to modulate blood pressure. Previous studies have demonstrated a role for both the SFO and OVLT in the hypertensive response to chronic AngII, yet it is unclear which intracellular signaling pathways are involved in this response. Overexpression of copper/zinc superoxide dismutase (CuZnSOD) in the SFO has been shown to attenuate the chronic hypertensive effects of AngII. Presently, we tested the hypothesis that elevated levels of superoxide (O2 (∙-)) in the OVLT contribute to the hypertensive effects …

Determining The Effect Of Knocking Out Microrna-21 On Subsarcolemmal And Interfibrillar Mitochondria, Madhur Batra

Theses and Dissertations

Type 2 diabetes mellitus is a growing problem across the world and has significant pathological changes associated with it, including diabetic cardiomyopathy, wherein cardiac function is reduced. MicroRNA-21 has been shown to play a role in both the heart and diabetes so it was thought that knocking out miR-21 could have a protective effect on oxidative phosphorylation function in diabetic mice. Subsarcolemmal and interfibrillar mitochondria were isolated from adult male WT, miR-21 KO, db/db, and double knockout mice (db/db and miR-21 KO cross) and evaluated for function. Knocking out miR-21 in diabetic mice showed a restorative effect in Complex I …

Analysis Of Ca²⁺ Mobilization Of Nanosecond Pulses In Cells, Iurii Semenov

Bioelectrics Publications

Exposure to nanosecond electric pulses (nsEPs) evokes transient rise of cytosolic free Ca²⁺ concentration ([Ca²⁺]i) in the cells. We quantified the external Ca²⁺ uptake, intracellular Ca²⁺ release and uncover interplay of these processes for CHO-K1 cells upon exposure to single 60 ns pulse in the range of amplitudes from 0 to 30 kV/cm. NsEPs are distinguished by the ability to electroporate intracellular membranes. We studied how duration of nsEPs is related to efficiency of intracellular membranes electroporation comparing ability of single 300-, 60- and 10 ns pulses to recruit Ca²⁺ from endoplasmic reticulum (ER) in respect to the uptake of …

Protein Kinase A And Epac Mediate Chronic Pain After Injury: Prolonged Inhibition By Endogenous Y1 Receptors In Dorsal Horn, Weisi Fu

Theses and Dissertations--Physiology

Inflammation or nerve injury sensitizes several populations of nociceptive neurons in the dorsal horn of the spinal cord, including those that express the neuropeptide Y (NPY) Y1 receptor (Y1R). Our overall hypothesis is that after tissue or nerve injury, these Y1R-expressing neurons enter a state of latent sensitization (LS) that contributes to vulnerability to the development of chronic pain; furthermore, LS is under the tonic inhibitory control of endogenous Y1R signaling. First, we evaluated the intracellular signaling pathways that become activated in Y1R-expressing neurons and participate in LS. To do this, we established behavioral models of inflammatory or neuropathic pain, …

Regulation Of Uv-Protective Pathways Downstream Of The Melanocortin 1 Receptor In Melanocytes, Erin M. Wolf Horrell

Theses and Dissertations--Physiology

Malignant cutaneous melanoma is the deadliest form of skin cancer, and a majority of melanoma diagnoses are a result of exposure to ultraviolet (UV) radiation. UV radiation causes DNA damage, which if not repaired correctly via nucleotide excision repair (NER) can result in mutations and melanomagenesis. The melanocortin 1 receptor (MC1R) is a G_s protein coupled receptor located on melanocyte plasma membranes and is involved in protecting the skin from UV induced damage. MC1R signaling results in the activation of two protective pathways: 1) induction of eumelanin synthesis downstream of micropthalmia-associated transcription factor (MITF) and 2) acceleration of NER …

Histological And Behavioral Consequences Of Repeated Mild Traumatic Brain Injury In Mice, Amanda Nicholle Bolton Hall

Theses and Dissertations--Physiology

The majority of the estimated three million traumatic brain injuries that occur each year are classified as “mild” and do not require surgical intervention. However, debilitating symptoms such as difficulties focusing on tasks, anxiety, depression, and visual deficits can persist chronically after a mild traumatic brain injury (TBI) even if an individual appears “fine”. These symptoms have been observed to worsen or be prolonged when an individual has suffered multiple mild TBIs. To test the hypothesis that increasing the amount of time between head injuries can reduce the histopathological and behavioral consequences of repeated mild TBI, a mouse model of …

Faster Movement Speed Results In Greater Tendon Strain During The Loaded Squat Exercise, Jacob E. Earp, Robert U. Newton, Prue Cormie, Anthony J. Blazevich

Research outputs 2014 to 2021

Introduction:

Tendon dynamics influence movement performance and provide the stimulus for long-term tendon adaptation. As tendon strain increases with load magnitude and decreases with loading rate, changes in movement speed during exercise should influence tendon strain.

Methods:

Ten resistance-trained men [squat one repetition maximum (1RM) to body mass ratio: 1.65 ± 0.12] performed parallel-depth back squat lifts with 60% of 1RM load at three different speeds: slow fixed-tempo (TS: 2-s eccentric, 1-s pause, 2-s concentric), volitional-speed without a pause (VS) and maximum-speed jump (JS). In each condition joint kinetics, quadriceps tendon length (L_T), patellar tendon force (F_{T …}

Interaction Between Angiotensin Ii And Bdnf In Modulating Sympathetic Nerve Activity, Bryan K. Becker

Theses & Dissertations

Over activation of the sympathetic nervous system is prevalent in many forms of cardiovascular disease such as chronic heart failure (CHF) and hypertension. Although increased neuronal renin-angiotensin system activity in presympathetic neurons has been well implicated in mediating this sympatho-excitation, many of the neuronal effects of angiotensin II (Ang II) signaling remain poorly understood. One particular mechanism of Ang II-mediated increases in presympathetic neuronal activity is through reductions in voltage-gated K⁺ currents. Another pathway that has profound effects on neuronal K⁺ currents and that has been previously implicated in Ang II-signaling is brain-derived neurotrophic factor (BDNF) activity through …

Hiv-1-Tat Protein Inhibits Sc35-Mediated Tau Exon 10 Inclusion Through Up-Regulation Of Dyrk1a Kinase, Ferdous Kadri, Marco Pacifici, Anna Wilk, Amanda Parker-Struckhoff, Luis Del Valle, Kurt F. Hauser, Pamela E. Knapp, Christopher Parsons, Duane Jeansonne, Adam Lassak, Francesca Peruzzi

School of Medicine Faculty Publications

The HIV-1 transactivator protein Tat is implicated in the neuronal damage that contributes to neurocognitive impairment affecting people living with HIV/AIDS. Aberrant splicing of TAU exon 10 results in tauopathies characterized by alterations in the proportion of TAU isoforms containing three (3R) or four (4R) microtubule-binding repeats. The splicing factor SC35/SRSF2 binds to nuclear RNA and facilitates the incorporation of exon 10 in the TAU molecule. Here, we utilized clinical samples, an animal model, and neuronal cell cultures and found that Tat promotes TAU 3R up-regulation through increased levels of phosphorylated SC35, which is retained in nuclear speckles. This mechanism …

Bdnf Contributes To Angiotensin Ii-Mediated Reductions In Peak Voltage-Gated K+ Current In Cultured Cath.A Cells., Bryan K. Becker, Han-Jun Wang, Changhai Tian, Irving H. Zucker

Journal Articles: Cellular & Integrative Physiology

Increased central angiotensin II (Ang II) levels contribute to sympathoexcitation in cardiovascular disease states such as chronic heart failure and hypertension. One mechanism by which Ang II increases neuronal excitability is through a decrease in voltage-gated, rapidly inactivating K(+) current (IA); however, little is known about how Ang II signaling results in reduced IA. Brain-derived neurotrophic factor (BDNF) has also been demonstrated to decrease IA and has signaling components common to Ang II. Therefore, we hypothesized that Ang II-mediated suppression of voltage-gated K(+) currents is due, in part, to BDNF signaling. Differentiated CATH.a, catecholaminergic cell line treated with BDNF for …

Diabetic Ketoacidosis: Pathophysiology And Treatment, Laura E. Mumme

The Kabod

The pathophysiology of DKA in patients with T1D is addressed, followed by a discussion of proper emergency treatment for this life-threatening condition.

Relevance Of The Carotid Body Chemoreflex In The Progression Of Heart Failure., David C. Andrade, Claudia Lucero, Camilo Toledo, Carlos Madrid, Noah J. Marcus, Harold D. Schultz, Rodrigo Del Rio

Journal Articles: Cellular & Integrative Physiology

Chronic heart failure (CHF) is a global health problem affecting millions of people. Autonomic dysfunction and disordered breathing patterns are commonly observed in patients with CHF, and both are strongly related to poor prognosis and high mortality risk. Tonic activation of carotid body (CB) chemoreceptors contributes to sympathoexcitation and disordered breathing patterns in experimental models of CHF. Recent studies show that ablation of the CB chemoreceptors improves autonomic function and breathing control in CHF and improves survival. These exciting findings indicate that alterations in CB function are critical to the progression of CHF. Therefore, better understanding of the physiology of …

Standardization Of The Experimental Autoimmune Myasthenia Gravis (Eamg) Model By Immunization Of Rats With Torpedo Californica Acetylcholine Receptors- Recommendations For Methods And Experimental Designs., Mario Losen, Pilar Martinez-Martinez, Peter C. Molenaar, Konstantinos Lazaridis, Socrates Tzartos, Talma Brenner, Rui-Sheng Duan, Jie Luo, Jon Lindstrom, Linda Kusner

Pharmacology and Physiology Faculty Publications

Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR) is characterized by a chronic, fatigable weakness of voluntary muscles. The production of autoantibodies involves the dysregulation of T cells which provide the environment for the development of autoreactive B cells. The symptoms are caused by destruction of the postsynaptic membrane and degradation of the AChR by IgG autoantibodies, predominantly of the G1 and G3 subclasses. Active immunization of animals with AChR from mammalian muscles, AChR from Torpedo or Electrophorus electric organs, and recombinant or synthetic AChR fragments generates a chronic model of MG, termed experimental autoimmune myasthenia gravis (EAMG). …

Plastin 3 Expression Does Not Modify Spinal Muscular Atrophy Severity In The ∆7 Sma Mouse, Vicki L. Mcgovern, Aurelie Massoni-Laporte, Xueyong Wang, Thanh T. Le, Hao T. Le, Mark M. Rich, Arthur H. M. Burghes

Neuroscience, Cell Biology & Physiology Faculty Publications

Spinal muscular atrophy is caused by loss of the SMN1 gene and retention of SMN2. TheSMN2 copy number inversely correlates with phenotypic severity and is a modifier of disease outcome. The SMN2 gene essentially differs from SMN1 by a single nucleotide in exon 7 that modulates the incorporation of exon 7 into the final SMN transcript. The majority of the SMN2transcripts lack exon 7 and this leads to a SMN protein that does not effectively oligomerize and is rapidly degraded. However theSMN2 gene does produce some full-length SMN and theSMN2 copy number along with how …

Higher Hepatic Mir-29 Expression In Undernourished Male Rats During The Postnatal Period Targets The Long-Term Repression Of Insulin-Like Growth Factor 1, Gurjeev Sohi, Andrew Revesz, Julie Ramkumar, Daniel B. Hardy

Physiology and Pharmacology Publications

A nutritional mismatch in postnatal life of low birth weight offspring increases the risk of developing the metabolic syndrome. Moreover, this is associated with decreased hepatic insulin-like growth factor 1 (Igf1) expression, leading to impaired growth and metabolism. Previously we have demonstrated that the timing of nutritional restoration in perinatal life can differentially programhepatic gene expression. While micro RNAs also play an important role in silencing gene expression, to date, the impact of a nutritional mismatch in neonatal life on their long-term expression has not been evaluated. Given the complementarity of miR-29 to the 3i-UTR of Igf1, we examined how …

Editorial: Carotid Body: A New Target For Rescuing Neural Control Of Cardiorespiratory Balance In Disease., Rodrigo Del Rio, Rodrigo Iturriaga, Harold D. Schultz

Journal Articles: Cellular & Integrative Physiology

No abstract provided.

Long-Term Hypoxia Alters Ovine Fetal Adrenal Enos And Cortisol Biosynthesis, Elizabeth Anne Newby

Loma Linda University Electronic Theses, Dissertations & Projects

Maintaining normal levels of cortisol in response to chronic stress, while retaining the ability to respond to acute stress, is important for ensuring normal fetal growth and development. Long-term hypoxia (LTH) causes adaptations in the fetal hypothalamopituitary- adrenal (HPA) axis that maintain basal cortisol levels but enhance production in response to a secondary stress. Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS) in the adrenal cortex, plays a significant role in regulating cortisol production in the LTH fetus. The production of NO is regulated by eNOS activity which can be altered via phosphorylation through key signaling pathways. In …