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Wan Y, White C, Robert N, Rogers MB, Szabo-Rogers HL. Localization of Tfap2β, Casq2, Penk, Zic1, and Zic3 Expression in the Developing Retina, Muscle, and Sclera of the Embryonic Mouse Eye. J Histochem Cytochem 2019; 67:863-871. [PMID: 31638440 DOI: 10.1369/0022155419885112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Optic development involves sequential interactions between several different tissue types, including the overlying ectoderm, adjacent mesoderm, and neural crest mesenchyme and the neuroectoderm. In an ongoing expression screen, we identified that Tfap2β, Casq2, Penk, Zic1, and Zic3 are expressed in unique cell types in and around the developing eye. Tfap2β, Zic1, and Zic3 are transcription factors, Casq2 is a calcium binding protein and Penk is a neurotransmitter. Tfap2β, Zic1, and Zic3 have reported roles in brain and craniofacial development, while Casq2 and Penk have unknown roles. These five genes are expressed in the major tissue types in the eye, including the muscles, nerves, cornea, and sclera. Penk expression is found in the sclera and perichondrium. At E12.5 and E15.5, the extra-ocular muscles express Casq2, the entire neural retina expresses Zic1, and Zic3 is expressed in the optic disk and lip of the optic cup. The expression of Tfap2β expanded from corneal epithelium to the neural retina between E12.5 to E15.5. These genes are expressed in similar domains as Hedgehog (Gli1, and Ptch1) and the Wnt (Lef1) pathways. The expression patterns of these five genes warrant further study to determine their role in eye morphogenesis.
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Affiliation(s)
- Yong Wan
- Center for Craniofacial Regeneration, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Casey White
- Center for Craniofacial Regeneration, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Nadine Robert
- Center for Craniofacial Regeneration, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Matthew B Rogers
- Department of Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Heather L Szabo-Rogers
- Center for Craniofacial Regeneration, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, PA.,Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA
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Willis BC, Pandit SV, Ponce-Balbuena D, Zarzoso M, Guerrero-Serna G, Limbu B, Deo M, Camors E, Ramirez RJ, Mironov S, Herron TJ, Valdivia HH, Jalife J. Constitutive Intracellular Na+ Excess in Purkinje Cells Promotes Arrhythmogenesis at Lower Levels of Stress Than Ventricular Myocytes From Mice With Catecholaminergic Polymorphic Ventricular Tachycardia. Circulation 2016; 133:2348-59. [PMID: 27169737 PMCID: PMC4902321 DOI: 10.1161/circulationaha.116.021936] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/03/2016] [Indexed: 11/18/2022]
Abstract
Supplemental Digital Content is available in the text. Background— In catecholaminergic polymorphic ventricular tachycardia (CPVT), cardiac Purkinje cells (PCs) appear more susceptible to Ca2+ dysfunction than ventricular myocytes (VMs). The underlying mechanisms remain unknown. Using a CPVT mouse (RyR2R4496C+/Cx40eGFP), we tested whether PC intracellular Ca2+ ([Ca2+]i) dysregulation results from a constitutive [Na+]i surplus relative to VMs. Methods and Results— Simultaneous optical mapping of voltage and [Ca2+]i in CPVT hearts showed that spontaneous Ca2+ release preceded pacing-induced triggered activity at subendocardial PCs. On simultaneous current-clamp and Ca2+ imaging, early and delayed afterdepolarizations trailed spontaneous Ca2+ release and were more frequent in CPVT PCs than CPVT VMs. As a result of increased activity of mutant ryanodine receptor type 2 channels, sarcoplasmic reticulum Ca2+ load, measured by caffeine-induced Ca2+ transients, was lower in CPVT VMs and PCs than respective controls, and sarcoplasmic reticulum fractional release was greater in both CPVT PCs and VMs than respective controls. [Na+]i was higher in both control and CPVT PCs than VMs, whereas the density of the Na+/Ca2+ exchanger current was not different between PCs and VMs. Computer simulations using a PC model predicted that the elevated [Na+]i of PCs promoted delayed afterdepolarizations, which were always preceded by spontaneous Ca2+ release events from hyperactive ryanodine receptor type 2 channels. Increasing [Na+]i monotonically increased delayed afterdepolarization frequency. Confocal imaging experiments showed that postpacing Ca2+ spark frequency was highest in intact CPVT PCs, but such differences were reversed on saponin-induced membrane permeabilization, indicating that differences in [Na+]i played a central role. Conclusions— In CPVT mice, the constitutive [Na+]i excess of PCs promotes triggered activity and arrhythmogenesis at lower levels of stress than VMs.
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Affiliation(s)
- B Cicero Willis
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Sandeep V Pandit
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Daniela Ponce-Balbuena
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Manuel Zarzoso
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Guadalupe Guerrero-Serna
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Bijay Limbu
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Makarand Deo
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Emmanuel Camors
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Rafael J Ramirez
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Sergey Mironov
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Todd J Herron
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - Héctor H Valdivia
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.)
| | - José Jalife
- From University of Michigan, Ann Arbor (B.C.W., S.V.P., D.P.-B., M.Z., G.G.-S., R.J.R., S.M., T.J.H., H.H.V., J.J.); Norfolk State University, VA (B.L., M.D.); University of Tennessee Health Science Center, Memphis (E.C.); and Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain (J.J.).
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Paavola J, Väänänen H, Larsson K, Penttinen K, Toivonen L, Kontula K, Laine M, Aalto-Setälä K, Swan H, Viitasalo M. Slowed depolarization and irregular repolarization in catecholaminergic polymorphic ventricular tachycardia: a study from cellular Ca2+ transients and action potentials to clinical monophasic action potentials and electrocardiography. Europace 2015; 18:1599-1607. [PMID: 26705554 DOI: 10.1093/europace/euv380] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/17/2015] [Indexed: 01/08/2023] Open
Abstract
AIMS Spontaneous Ca2+ release leads to afterdepolarizations and triggered arrhythmia in catecholaminergic polymorphic ventricular tachycardia (CPVT). Irregular Ca2+ release is hypothesized to manifest as slowed depolarization and irregular repolarization. Our goal was to study depolarization and repolarization abnormalities in CPVT, as they remain largely uninvestigated. METHODS AND RESULTS We studied intracellular Ca2+ handling and action potentials (APs) in an induced pluripotent stem cell (iPSC) model of CPVT. Induced pluripotent stem cell cardiomyocytes from a RyR2-P2328S patient showed increased non-alternating variability of Ca2+ transients in response to isoproterenol. β-Agonists decreased AP upslope velocity in CPVT cells and in monophasic AP recordings of CPVT patients. We compared 24 h electrocardiograms (ECGs) of 19 CPVT patients carrying RyR2 mutations and 19 healthy controls. Short-term variability (STV) of the QT interval was 6.9 ± 0.5 ms in CPVT patients vs. 5.5 ± 0.4 ms in controls (P < 0.05) and associated with a history of arrhythmic events. Mean T-wave alternans (TWA) was 25 ± 1.4 µV in CPVT patients vs. 31 ± 2.0 µV in controls (P < 0.05). Older CPVT patients showed lower maximal upslope velocity of the ECG R-spike than control patients. CONCLUSION Catecholaminergic polymorphic ventricular tachycardia patients show higher STV of repolarization but lower TWA on the 24 h ECG than control patients, which is likely to reflect increased non-alternating variability of Ca2+ release by mutant RyR2s as observed in vitro. β-Agonists slow depolarization in RyR2-mutant cells and in CPVT patients. These findings may constitute a marker of arrhythmogenicity.
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Affiliation(s)
- Jere Paavola
- Minerva Foundation Institute for Medical Research, Helsinki, Finland .,Division of Cardiology, Heart and Lung Center HUS, Helsinki University Central Hospital, Helsinki, Finland
| | - Heikki Väänänen
- Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, Finland
| | - Kim Larsson
- School of Medicine, University of Tampere, Tampere, Finland.,Biomeditech, University of Tampere, Tampere, Finland
| | - Kirsi Penttinen
- School of Medicine, University of Tampere, Tampere, Finland.,Biomeditech, University of Tampere, Tampere, Finland
| | - Lauri Toivonen
- Division of Cardiology, Heart and Lung Center HUS, Helsinki University Central Hospital, Helsinki, Finland
| | - Kimmo Kontula
- Department of Medicine, University of Helsinki, and Helsinki University Hospital, Helsinki, Finland
| | - Mika Laine
- Minerva Foundation Institute for Medical Research, Helsinki, Finland.,Division of Cardiology, Heart and Lung Center HUS, Helsinki University Central Hospital, Helsinki, Finland
| | - Katriina Aalto-Setälä
- School of Medicine, University of Tampere, Tampere, Finland.,Biomeditech, University of Tampere, Tampere, Finland.,Heart Center, Tampere University Hospital, Tampere, Finland
| | - Heikki Swan
- Division of Cardiology, Heart and Lung Center HUS, Helsinki University Central Hospital, Helsinki, Finland
| | - Matti Viitasalo
- Division of Cardiology, Heart and Lung Center HUS, Helsinki University Central Hospital, Helsinki, Finland
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Němec J, Kim JJ, Salama G. The link between abnormal calcium handling and electrical instability in acquired long QT syndrome--Does calcium precipitate arrhythmic storms? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:210-21. [PMID: 26631594 DOI: 10.1016/j.pbiomolbio.2015.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/17/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022]
Abstract
Release of Ca(2+) ions from sarcoplasmic reticulum (SR) into myocyte cytoplasm and their binding to troponin C is the final signal form myocardial contraction. Synchronous contraction of ventricular myocytes is necessary for efficient cardiac pumping function. This requires both shuttling of Ca(2+) between SR and cytoplasm in individual myocytes, and organ-level synchronization of this process by means of electrical coupling among ventricular myocytes. Abnormal Ca(2+) release from SR causes arrhythmias in the setting of CPVT (catecholaminergic polymorphic ventricular tachycardia) and digoxin toxicity. Recent optical mapping data indicate that abnormal Ca(2+) handling causes arrhythmias in models of both repolarization impairment and profound bradycardia. The mechanisms involve dynamic spatial heterogeneity of myocardial Ca(2+) handling preceding arrhythmia onset, cell-synchronous systolic secondary Ca(2+) elevation (SSCE), as well as more complex abnormalities of intracellular Ca(2+) handling detected by subcellular optical mapping in Langendorff-perfused hearts. The regional heterogeneities in Ca(2+) handling cause action potential (AP) heterogeneities through sodium-calcium exchange (NCX) activation and eventually overwhelm electrical coupling of the tissue. Divergent Ca(2+) dynamics among different myocardial regions leads to temporal instability of AP duration and - on the patient level - in T wave lability. Although T-wave alternans has been linked to cardiac arrhythmias, non-alternans lability is observed in pre-clinical models of the long QT syndrome (LQTS) and CPVT, and in LQTS patients. Analysis of T wave lability may provide a real-time window on the abnormal Ca(2+) dynamics causing specific arrhythmias such as Torsade de Pointes (TdP).
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Affiliation(s)
- Jan Němec
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jong J Kim
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Guy Salama
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Krokhaleva Y, Patel D, Shah H, Shusterman V, Saba S, Němec J. Increased Nonalternans Repolarization Variability Precedes Ventricular Tachycardia Onset in Patients with Implantable Defibrillators. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 39:140-8. [PMID: 26548642 DOI: 10.1111/pace.12785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 09/29/2015] [Accepted: 10/28/2015] [Indexed: 11/29/2022]
Abstract
BACKROUND T-wave alternans (TWA) is associated with ventricular tachycardia (VT). Nonalternans repolarization variability (NARV) precedes VT in certain experimental models, but its link to clinical arrhythmia is unproven. This study was conducted to determine if NARV increases prior to VT in patients with implantable cardioverter defibrillators (ICDs). METHODS TWA and NARV were calculated from shock-channel electrograms preceding onset of VT or non-VT events in patients with an ICD. In each patient, presence of both a VT and a non-VT event with the same QRS morphology before the event was required. Mixed linear model was used for data analysis, using heart rate (HR) and the number of analyzed beats as covariates. RESULTS Five hundred and sixty-eight events from 64 patients (males/females 51/13, 67 ± 13 years) were analyzed. HR preceding non-VT events was higher than before VT events (RR interval 595 ± 159 vs 706 ± 111 ms; P < 0.0001). Both TWA and NARV increased with increasing HR (P < 0.001). TWA decreased with increasing number of analyzed beats. When controlled for number of analyzed beats and HR, both TWA and NARV were higher before VT than before non-VT events (P < 0.002 and P < 0.0005, respectively). CONCLUSIONS NARV is elevated prior to spontaneous VT onset. Both NARV and TWA increase with HR. The decrease of TWA with increasing number of analyzed beats may indicate contamination with NARV or noise when only a small number of beats is available for analysis. NARV might be useful for VT prediction in the future.
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Affiliation(s)
| | - Divyang Patel
- Department of Internal Medicine, Duke University, North Carolina
| | - Hemal Shah
- North Bethesda Hospital, Cincinnati, Ohio
| | | | - Samir Saba
- Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jan Němec
- Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
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