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In Vivo Effectiveness And Safety Of Probiotics On Prophylaxis And Treatment Of Oral Candidiasis: A Systematic Review And Meta-Analysis, Lijun Hu, Mimi Zhou, Andrew L. Young, Weiwei Zhao, Zhimin Yan Jul 2019

In Vivo Effectiveness And Safety Of Probiotics On Prophylaxis And Treatment Of Oral Candidiasis: A Systematic Review And Meta-Analysis, Lijun Hu, Mimi Zhou, Andrew L. Young, Weiwei Zhao, Zhimin Yan

All Dugoni School of Dentistry Faculty Articles

BACKGROUND: To systematically review and assess the in vivo effectiveness and safety of probiotics for prophylaxis and treating oral candidiasis.

METHODS: A literature search for studies published in English until August 1, 2018 was conducted in the following databases: PubMed, EMBASE, Cochrane Library, and Web of Science. Randomized controlled clinical trials and experimental mouse animal model studies comparing probiotics (at any dosage and in any form) with control groups (placebo, blank control or other agents) and reporting outcomes of the prophylactic and therapeutic effects were considered for inclusion. A descriptive study and, potentially, a meta-analysis were planned.

RESULTS: Six randomized …


Pretreatment With A Heat-Killed Probiotic Modulates The Nlrp3 Inflammasome And Attenuates Colitis-Associated Colorectal Cancer In Mice., I-Che Chung, Chun-Nan Ouyang, Sheng-Ning Yuan, Hsin-Chung Lin, Kuo-Yang Huang, Pao-Shu Wu, Chia-Yuan Liu, Kuen-Jou Tsai, Lai-Keng Loi, Yu-Jen Chen, An-Ko Chung, David M. Ojcius, Yu-Sun Chang, Lih-Chyang Chen Feb 2019

Pretreatment With A Heat-Killed Probiotic Modulates The Nlrp3 Inflammasome And Attenuates Colitis-Associated Colorectal Cancer In Mice., I-Che Chung, Chun-Nan Ouyang, Sheng-Ning Yuan, Hsin-Chung Lin, Kuo-Yang Huang, Pao-Shu Wu, Chia-Yuan Liu, Kuen-Jou Tsai, Lai-Keng Loi, Yu-Jen Chen, An-Ko Chung, David M. Ojcius, Yu-Sun Chang, Lih-Chyang Chen

All Dugoni School of Dentistry Faculty Articles

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Inflammation contributes to cancer development and inflammatory bowel disease is an important risk factor for CRC. The aim of this study is to assess whether a widely used probiotic Enterococcus faecalis can modulate the NLRP3 inflammasome and protect against colitis and colitis-associated CRC. We studied the effect of heat-killed cells of E. faecalis on NLRP3 inflammasome activation in THP-1-derived macrophages. Pretreatment of E. faecalis or NLRP3 siRNA can inhibit NLRP3 inflammasome activation in macrophages in response to fecal content or commensal microbes, P. mirabilis or E. coli, according …


Developmental Expression Of Monocarboxylate Transporter 1 And 4 In Rat Liver, Michael Ng, Justin Louie, Jieyun Cao, Melanie A. Felmlee Jan 2019

Developmental Expression Of Monocarboxylate Transporter 1 And 4 In Rat Liver, Michael Ng, Justin Louie, Jieyun Cao, Melanie A. Felmlee

School of Pharmacy Faculty Articles

PURPOSE: Monocarboxylate transporters (MCT) are proton-coupled integral membrane proteins that control the influx and efflux of endogenous monocarboxylates such as lactate, acetate and pyruvate. They also transport and mediate the clearance of drugs such as valproate and gamma-hydroxybutyrate. CD147 functions as ancillary protein that chaperones MCT1 and MCT4 to the cell membrane. There is limited data on the maturation of MCT and CD147 expression in tissues related to drug distribution and clearance. The objective of the present study was to quantify hepatic MCT1, MCT4, and CD147 mRNA, whole cell and membrane protein expression from birth to sexual maturity.

METHODS: Liver …


A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland Nov 2018

A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland

School of Pharmacy Faculty Articles

Action potentials (APs) are the functional units of fast electrical signaling in excitable cells. The upstroke and downstroke of an AP is generated by the competing and asynchronous action of Na+- and K+-selective voltage-gated conductances. Although a mixture of voltage-gated channels has been long recognized to contribute to the generation and temporal characteristics of the AP, understanding how each of these proteins function and are regulated during electrical signaling remains the subject of intense research. AP properties vary among different cellular types because of the expression diversity, subcellular location, and modulation of ion channels. These complexities, in addition to the …


Vwa Proteins Of Leptospira Interrogans Induce Hemorrhage In Leptospirosis By Competitive Inhibition Of Vwf/Gpib-Mediated Platelet Aggregation., Jia-Qi Fang, Muhammad Imran, Wei-Lin Hu, David M. Ojcius, Yang Li, Yu-Mei Ge, Kai-Xuan Li, Xu'ai Lin, Jie Yan Nov 2018

Vwa Proteins Of Leptospira Interrogans Induce Hemorrhage In Leptospirosis By Competitive Inhibition Of Vwf/Gpib-Mediated Platelet Aggregation., Jia-Qi Fang, Muhammad Imran, Wei-Lin Hu, David M. Ojcius, Yang Li, Yu-Mei Ge, Kai-Xuan Li, Xu'ai Lin, Jie Yan

All Dugoni School of Dentistry Faculty Articles

BACKGROUD: Leptospira interrogans is the major causative agent of leptospirosis, a worldwide zoonotic disease. Hemorrhage is a typical pathological feature of leptospirosis. Binding of von Willebrand factor (vWF) to platelet glycoprotein-Ibα (GPIbα) is a crucial step in initiation of platelet aggregation. The products of L. interrogans vwa-I and vwa-II genes contain vWF-A domains, but their ability to induce hemorrhage has not been determined.

METHODS: Human (Hu)-platelet- and Hu-GPIbα-binding abilities of the recombinant proteins expressed by L. interrogans strain Lai vwa-I and vwa-II genes (rLep-vWA-I and rLep-vWA-II) were detected by flowcytometry, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Hu-platelet …


A Novel Fas-Binding Outer Membrane Protein And Lipopolysaccharide Of Leptospira Interrogans Induce Macrophage Apoptosis Through The Fas/Fasl-Caspase-8/-3 Pathway., Peng Du, Shi-Jun Li, David M. Ojcius, Kai-Xuan Li, Wei-Lin Hu, Xu'ai Lin, Ai-Hua Sun, Jie Yan Jul 2018

A Novel Fas-Binding Outer Membrane Protein And Lipopolysaccharide Of Leptospira Interrogans Induce Macrophage Apoptosis Through The Fas/Fasl-Caspase-8/-3 Pathway., Peng Du, Shi-Jun Li, David M. Ojcius, Kai-Xuan Li, Wei-Lin Hu, Xu'ai Lin, Ai-Hua Sun, Jie Yan

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Leptospira interrogans is the major causative agent of leptospirosis, an emerging, globally spreading zoonotic infectious disease. The pathogen induces macrophage apoptosis, but the molecular basis and mechanism remain unknown. In the present study, we found that L. interrogans caused apoptosis of phagocytosis-inhibited macrophages, and the product of the L. interrogans LB047 gene (Lep-OMP047) was the unique protein captured by mouse and human Fas proteins. The recombinant expressed Lep-OMP047 (rLep-OMP047) strongly bound mouse and human Fas proteins with equilibrium association constant (K


Nadph Oxidase 4 Modulates Hepatic Responses To Lipopolysaccharide Mediated By Toll-Like Receptor-4., Anand Singh, Bhargav Koduru, Cameron Carlisle, Hasina Akhter, Rui-Ming Liu, Katrin Schroder, Ralf P. Brandes, David M. Ojcius Oct 2017

Nadph Oxidase 4 Modulates Hepatic Responses To Lipopolysaccharide Mediated By Toll-Like Receptor-4., Anand Singh, Bhargav Koduru, Cameron Carlisle, Hasina Akhter, Rui-Ming Liu, Katrin Schroder, Ralf P. Brandes, David M. Ojcius

All Dugoni School of Dentistry Faculty Articles

Chronic inflammation plays a key role in development of many liver diseases. Stimulation of Toll-like receptor 4 (TLR4) by bacterial lipopolysaccharide (LPS) initiates inflammation and promotes development of hepatocellular carcinoma and other liver diseases. NADPH oxidases contribute to LPS-induced reactive oxygen species (ROS) production and modulate TLR responses, but whether these enzymes function in TLR4 responses of hepatocytes is unknown. In the present work, we examined the role of NADPH oxidase 4 (Nox4) in LPS-induced TLR4 responses in human hepatoma cells and wildtype and Nox4-deficient mice. We found that LPS increased expression of Nox4, TNF-α, and proliferating cell nuclear antigen …


Mononuclear-Macrophages But Not Neutrophils Act As Major Infiltrating Anti-Leptospiral Phagocytes During Leptospirosis., Xu Chen, Shi-Jun Li, David M. Ojcius, Ai-Hua Sun, Wei-Lin Hu, Xu'ai Lin, Jie Yan Jan 2017

Mononuclear-Macrophages But Not Neutrophils Act As Major Infiltrating Anti-Leptospiral Phagocytes During Leptospirosis., Xu Chen, Shi-Jun Li, David M. Ojcius, Ai-Hua Sun, Wei-Lin Hu, Xu'ai Lin, Jie Yan

All Dugoni School of Dentistry Faculty Articles

OBJECTIVE: To identify the major infiltrating phagocytes during leptospirosis and examine the killing mechanism used by the host to eliminate Leptospira interrogans.

METHODS: Major infiltrating phagocytes in Leptospira-infected C3H/HeJ mice were detected by immunohistochemistry. Chemokines and vascular endothelial cell adhesion molecules (VECAMs) of Leptospira-infected mice and leptospirosis patients were detected by microarray and immunohistochemistry. Leptospira-phagocytosing and -killing abilities of human or mouse macrophages and neutrophils, and the roles of intracellular ROS, NO and [Ca2+]i in Leptospira-killing process were evaluated by confocal microscopy and spectrofluorimetry.

RESULTS: Peripheral blood mononuclear-macrophages rather than neutrophils were the main infiltrating phagocytes in the lungs, liver …


Retigabine Holds Kv7 Channels Open And Stabilizes The Resting Potential, Aaron Corbin-Leftwich, Sayeed M. Mossadeq, Junghoon Ha, Iwona Ruchala, Audrey Han Ngoc Le, Carlos A. Villalba-Galea Mar 2016

Retigabine Holds Kv7 Channels Open And Stabilizes The Resting Potential, Aaron Corbin-Leftwich, Sayeed M. Mossadeq, Junghoon Ha, Iwona Ruchala, Audrey Han Ngoc Le, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The anticonvulsant Retigabine is a KV7 channel agonist used to treat hyperexcitability disorders in humans. Retigabine shifts the voltage dependence for activation of the heteromeric KV7.2/KV7.3 channel to more negative potentials, thus facilitating activation. Although the molecular mechanism underlying Retigabine's action remains unknown, previous studies have identified the pore region of KV7 channels as the drug's target. This suggested that the Retigabine-induced shift in voltage dependence likely derives from the stabilization of the pore domain in an open (conducting) conformation. Testing this idea, we show that the heteromeric KV7.2/KV7.3 channel has at least two open states, which we named O1 …


Functional Local Renin-Angiotensin System In Human And Rat Periodontal Tissue, Carlos Ferreira Santos, Ana Carolina Morandini, Thiago José Dionísio, Flávio A. Faria, Marta C. Lima, Caio M. Figueiredo, Bella L. Colombini-Ishikiriama, Carla Renata Sipert, Rubens P. Maciel, Ana P. Akashi, Gabriela P. Souza, Gustavo P. Garlet, Camila O. Rodini, Sandra L. Amaral, Christiane Becari, Maria C. Salgado, Eduardo B. Oliveira, Isaac Matus, Daniela N. Didier, Andrew S. Greene Jan 2015

Functional Local Renin-Angiotensin System In Human And Rat Periodontal Tissue, Carlos Ferreira Santos, Ana Carolina Morandini, Thiago José Dionísio, Flávio A. Faria, Marta C. Lima, Caio M. Figueiredo, Bella L. Colombini-Ishikiriama, Carla Renata Sipert, Rubens P. Maciel, Ana P. Akashi, Gabriela P. Souza, Gustavo P. Garlet, Camila O. Rodini, Sandra L. Amaral, Christiane Becari, Maria C. Salgado, Eduardo B. Oliveira, Isaac Matus, Daniela N. Didier, Andrew S. Greene

All Dugoni School of Dentistry Faculty Articles

The initiation or progression of periodontitis might involve a local renin-angiotensin system (RAS) in periodontal tissue. The aim of this study was to further characterize the local RAS in human and rat periodontal tissues between healthy and periodontally-affected tissue. Components of the RAS were investigated using in vitro, ex vivo and in vivo experiments involving both human and Wistar rat periodontium. Although not upregulated when challenged with P. gingivalis-lipopolysaccharide, human gingival and periodontal ligament fibroblasts expressed RAS components. Likewise, healthy and inflamed human gingiva expressed RAS components, some of which were shown to be functional, yet no differences in expression …


Neurotrophic Factor Gdnf Promotes Survival Of Salivary Stem Cells, Nan (Tori) Xiao, Yuan Lin, Hongbin Cao, Davud Sirjani, Amato J. Giaccia, Albert C. Koong, Christina S. Kong, Maximilian Diehn, Quynh-Thu Le Aug 2014

Neurotrophic Factor Gdnf Promotes Survival Of Salivary Stem Cells, Nan (Tori) Xiao, Yuan Lin, Hongbin Cao, Davud Sirjani, Amato J. Giaccia, Albert C. Koong, Christina S. Kong, Maximilian Diehn, Quynh-Thu Le

All Dugoni School of Dentistry Faculty Articles

Stem cell-based regenerative therapy is a promising treatment for head and neck cancer patients that suffer from chronic dry mouth (xerostomia) due to salivary gland injury from radiation therapy. Current xerostomia therapies only provide temporary symptom relief, while permanent restoration of salivary function is not currently feasible. Here, we identified and characterized a stem cell population from adult murine submandibular glands. Of the different cells isolated from the submandibular gland, this specific population, Lin-CD24+c-Kit+Sca1+, possessed the highest capacity for proliferation, self renewal, and differentiation during serial passage in vitro. Serial transplantations of this stem cell population into the submandibular gland …


The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea Dec 2013

The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The voltage dependence of charges in voltage-sensitive proteins, typically displayed as charge versus voltage (Q-V) curves, is often quantified by fitting it to a simple two-state Boltzmann function. This procedure overlooks the fact that the fitted parameters, including the total charge, may be incorrect if the charge is moving in multiple steps. We present here the derivation of a general formulation for Q-V curves from multistate sequential models, including the case of infinite number of states. We demonstrate that the commonly used method to estimate the charge per molecule using a simple Boltzmann fit is not only inadequate, but in …


Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla Nov 2013

Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located in the N terminus. These VSDs are constituted by four putative transmembrane segments (S1 to S4) resembling those found in voltage-gated ion channels. The putative fourth segment (S4) of the VSD contains positive residues that likely function as voltage-sensing elements. To study in detail how these residues sense the plasma membrane potential, we have focused on five arginines in the S4 segment of the Ciona intestinalis VSP (Ci-VSP). After implementing a histidine scan, here we show that four arginine-to-histidine mutants, namely R223H to …


Pick1 And Ica69 Control Insulin Granule Trafficking And Their Deficiencies Lead To Impaired Glucose Tolerance, Mian Cao, Zhuo Mao, Chuen Kam, Nan (Tori) Xiao, Xiaoxing Cao, Chong Shen, Kenneth K. Y. Cheng, Aimin Xu, Kwong-Man Lee, Liwen Jiang, Jun Xia Apr 2013

Pick1 And Ica69 Control Insulin Granule Trafficking And Their Deficiencies Lead To Impaired Glucose Tolerance, Mian Cao, Zhuo Mao, Chuen Kam, Nan (Tori) Xiao, Xiaoxing Cao, Chong Shen, Kenneth K. Y. Cheng, Aimin Xu, Kwong-Man Lee, Liwen Jiang, Jun Xia

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Diabetes is a metabolic disorder characterized by hyperglycemia. Insulin, which is secreted by pancreatic beta cells, is recognized as the critical regulator of blood glucose, but the molecular machinery responsible for insulin trafficking remains poorly defined. In particular, the roles of cytosolic factors that govern the formation and maturation of insulin granules are unclear. Here we report that PICK1 and ICA69, two cytosolic lipid-binding proteins, formed heteromeric BAR-domain complexes that associated with insulin granules at different stages of their maturation. PICK1-ICA69 heteromeric complexes associated with immature secretory granules near the trans-Golgi network (TGN). A brief treatment of Brefeldin A, which …


Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla Nov 2012

Molecular Mechanism For Depolarization-Induced Modulation Of Kv Channel Closure, Alain J. Labro, Jerome J. Lacroix, Carlos A. Villalba-Galea, Dirk J. Snyders, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage-dependent potassium (Kv) channels provide the repolarizing power that shapes the action potential duration and helps control the firing frequency of neurons. The K(+) permeation through the channel pore is controlled by an intracellularly located bundle-crossing (BC) gate that communicates with the voltage-sensing domains (VSDs). During prolonged membrane depolarizations, most Kv channels display C-type inactivation that halts K(+) conduction through constriction of the K(+) selectivity filter. Besides triggering C-type inactivation, we show that in Shaker and Kv1.2 channels (expressed in Xenopus laevis oocytes), prolonged membrane depolarizations also slow down the kinetics of VSD deactivation and BC gate closure during the …


A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver Nov 2012

A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver

School of Pharmacy Faculty Articles

In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity …


Controlling The Activity Of A Phosphatase And Tensin Homolog (Pten) By Membrane Potential, Jérôme J. Lacroix, Christian R. Halaszovich, Daniela N. Schreiber, Michael G. Leitner, Francisco Bezanilla, Dominik Oliver, Carlos A. Villalba-Galea May 2011

Controlling The Activity Of A Phosphatase And Tensin Homolog (Pten) By Membrane Potential, Jérôme J. Lacroix, Christian R. Halaszovich, Daniela N. Schreiber, Michael G. Leitner, Francisco Bezanilla, Dominik Oliver, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The recently discovered voltage-sensitive phosphatases (VSPs) hydrolyze phosphoinositides upon depolarization of the membrane potential, thus representing a novel principle for the transduction of electrical activity into biochemical signals. Here, we demonstrate the possibility to confer voltage sensitivity to cytosolic enzymes. By fusing the tumor suppressor PTEN to the voltage sensor of the prototypic VSP from Ciona intestinalis, Ci-VSP, we generated chimeric proteins that are voltage-sensitive and display PTEN-like enzymatic activity in a strictly depolarization-dependent manner in vivo. Functional coupling of the exogenous enzymatic activity to the voltage sensor is mediated by a phospholipid-binding motif at the interface between voltage sensor …


Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla Jul 2009

Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla

School of Pharmacy Faculty Articles

The Ciona intestinalis voltage sensor-containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues …


Pick1 Deficiency Causes Male Infertility In Mice By Disrupting Acrosome Formation, Nan (Tori) Xiao, Chuen Kam, Chong Shen, Wenying Jin, Junqi Wang, Kwong Man Lee, Liwen Jiang, Jun Xia Apr 2009

Pick1 Deficiency Causes Male Infertility In Mice By Disrupting Acrosome Formation, Nan (Tori) Xiao, Chuen Kam, Chong Shen, Wenying Jin, Junqi Wang, Kwong Man Lee, Liwen Jiang, Jun Xia

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Protein interacting with C kinase 1 (PICK1) is a peripheral membrane protein involved in protein trafficking, a function that has been well characterized in neurons. Here, we report that male mice deficient in PICK1 are infertile and have a phenotype resembling the human disease globozoospermia. The primary defect in the testes of Pick1-knockout mice was fragmentation of acrosomes in the early stages of spermiogenesis. This fragmentation was followed by defects in nuclear elongation and mitochondrial sheath formation, leading to round-headed sperm, reduced sperm count, and severely impaired sperm motility. We found that PICK1 interacted with Golgi-associated PDZ- and coiled-coil motif-containing …


Ryanodine Receptor Adaptation, Michael Fill, A. Zahradníková, Carlos A. Villalba-Galea, I. Zahradník, A. L. Escobar, S. Györke Dec 2000

Ryanodine Receptor Adaptation, Michael Fill, A. Zahradníková, Carlos A. Villalba-Galea, I. Zahradník, A. L. Escobar, S. Györke

School of Pharmacy Faculty Articles

In the heart, depolarization during the action potential activates voltage-dependent Ca2+ channels that mediate a small, localized Ca2+ influx (ICa). This small Ca2+ signal activates specialized Ca2+ release channels, the ryanodine receptors (RyRs), in the sarcoplasmic reticulum (SR). This process is called Ca2+-induced Ca2+ release (CICR). Intuitively, the CICR process should be self-regenerating because the Ca2+ released from the SR should feedback and activate further SR Ca2+ release. However, the CICR process is precisely controlled in the heart and, consequently, some sort of negative control mechanism(s) must exist to …