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Rios CI, DiCarlo AL, Harrison L, Prasanna PGS, Buchsbaum JC, Rudokas MW, Gomes L, Winters TA. Advanced Technologies in Radiation Research. Radiat Res 2024; 201:338-365. [PMID: 38453643 PMCID: PMC11046920 DOI: 10.1667/rade-24-00003.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/22/2024] [Indexed: 03/09/2024]
Abstract
The U.S. Government is committed to maintaining a robust research program that supports a portfolio of scientific experts who are investigating the biological effects of radiation exposure. On August 17 and 18, 2023, the Radiation and Nuclear Countermeasures Program, within the National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), partnered with the National Cancer Institute, NIH, the National Aeronautics and Space Administration, and the Radiation Injury Treatment Network to convene a workshop titled, Advanced Technologies in Radiation Research (ATRR), which focused on the use of advanced technologies under development or in current use to accelerate radiation research. This meeting report provides a comprehensive overview of the research presented at the workshop, which included an assembly of subject matter experts from government, industry, and academia. Topics discussed during the workshop included assessments of acute and delayed effects of radiation exposure using modalities such as clustered regularly interspaced short palindromic repeats (CRISPR) - based gene editing, tissue chips, advanced computing, artificial intelligence, and immersive imaging techniques. These approaches are being applied to develop products to diagnose and treat radiation injury to the bone marrow, skin, lung, and gastrointestinal tract, among other tissues. The overarching goal of the workshop was to provide an opportunity for the radiation research community to come together to assess the technological landscape through sharing of data, methodologies, and challenges, followed by a guided discussion with all participants. Ultimately, the organizers hope that the radiation research community will benefit from the workshop and seek solutions to scientific questions that remain unaddressed. Understanding existing research gaps and harnessing new or re-imagined tools and methods will allow for the design of studies to advance medical products along the critical path to U.S. Food and Drug Administration approval.
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Affiliation(s)
- Carmen I. Rios
- Radiation and Nuclear Countermeasures Program/Division of Allergy, Immunology, and Transplantation/National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIH), Rockville, Maryland
| | - Andrea L. DiCarlo
- Radiation and Nuclear Countermeasures Program/Division of Allergy, Immunology, and Transplantation/National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIH), Rockville, Maryland
| | - Lynn Harrison
- Division of Biological and Physical Sciences/National Aeronautics and Space Administration, Houston, Texas
| | - Pataje G. S. Prasanna
- Division of Cancer Treatment and Diagnosis/National Cancer Institute/NIH, Gaithersburg, Maryland
| | - Jeffrey C. Buchsbaum
- Division of Cancer Treatment and Diagnosis/National Cancer Institute/NIH, Gaithersburg, Maryland
| | - Michael W. Rudokas
- Radiation and Nuclear Countermeasures Program/Division of Allergy, Immunology, and Transplantation/National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIH), Rockville, Maryland
| | - Lauren Gomes
- Radiation and Nuclear Countermeasures Program/Division of Allergy, Immunology, and Transplantation/National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIH), Rockville, Maryland
| | - Thomas A. Winters
- Radiation and Nuclear Countermeasures Program/Division of Allergy, Immunology, and Transplantation/National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIH), Rockville, Maryland
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Rudokas MW, Cacheux M, Wu X, Hummel ME, Young LH, Akar FG. Role of AMPK pathway inactivation in high fat diet related cardiac electrophysiological remodeling. Biophys J 2023; 122:380a-381a. [PMID: 36783933 DOI: 10.1016/j.bpj.2022.11.2089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Michael W Rudokas
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Marine Cacheux
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Xiaohong Wu
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Madelyn E Hummel
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Lawrence H Young
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Fadi G Akar
- Department of Internal Medicine, Section of Cardiovascular Medicine, Yale School of Medicine, New Haven, CT, USA
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Rudokas MW, Cacheux M, Wu X, Young LH, Akar FG. Abstract P3052: Dysregulation Of The Ampk-drp1 Axis Promotes Pathophysiological Remodeling Of Mitochondrial Ultrastructure And Ventricular Electrophysiological Function. Circ Res 2022. [DOI: 10.1161/res.131.suppl_1.p3052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
AMP-activated protein kinase (AMPK), a master metabolic sensor, plays a central role in the regulation of mitochondrial (mito) function. AMPK activation inhibits mito fission potentially by modulating mito dynamics proteins, including dynamin-related protein 1 (DRP1). The role of the AMPK-DRP1 axis in electrophysiological (EP) function is unknown.
Methods:
We examined the impact of myocardial AMPK inactivation on mito ultrastructure by electron microscopy, mito dynamics proteins by western blot, and EP function by optical mapping in mice expressing an AMPK kinase dead isoform (AMPK-KD, N=3-7) vs littermate controls (Ctrl, N=3-6).
Results:
Quantification of mito morphology revealed increased mito area consistent with swelling (0.53 μm
2
vs 0.80 μm
2
, p<0.0001) and decreased mito count (0.68 mito/μm
2
vs 0.44 mito/μm
2
, p=0.13) in AMPK-KD vs Ctrl. Immunoblots revealed decreased DRP1 phosphorylation at S637 (a fission inhibiting site) with no major change in total DRP1, S616 phospho-DRP1, MFN1/2 or OPA1 levels in AMPK-KD. High resolution optical mapping of
ex vivo
perfused hearts uncovered marked (by 39.5%, p<0.001) conduction slowing (
Figure
) and a moderate increase in AP duration (43.8 ms vs 49.7 ms, p<0.05) reflecting widespread ventricular EP remodeling in AMPK-KD. Of note, discrete lines of functional conduction block were observed in 4/7 AMPK-KD but not Ctrl hearts consistent with pro-arrhythmic remodeling.
Conclusions:
Myocardial AMPK pathway inactivation causes mito ultrastructural abnormalities and pathological EP remodeling. The AMPK-DRP1 axis may be a novel target for arrhythmia suppression in metabolic disorders with defective AMPK downstream signaling.
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Sherpa RT, Fiore C, Moshal KS, Wadsworth A, Rudokas MW, Agarwal SR, Harvey RD. Mitochondrial A-kinase anchoring proteins in cardiac ventricular myocytes. Physiol Rep 2021; 9:e15015. [PMID: 34514737 PMCID: PMC8436057 DOI: 10.14814/phy2.15015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022] Open
Abstract
Compartmentation of cAMP signaling is a critical factor for maintaining the integrity of receptor-specific responses in cardiac myocytes. This phenomenon relies on various factors limiting cAMP diffusion. Our previous work in adult rat ventricular myocytes (ARVMs) indicates that PKA regulatory subunits anchored to the outer membrane of mitochondria play a key role in buffering the movement of cytosolic cAMP. PKA can be targeted to discrete subcellular locations through the interaction of both type I and type II regulatory subunits with A-kinase anchoring proteins (AKAPs). The purpose of this study is to identify which AKAPs and PKA regulatory subunit isoforms are associated with mitochondria in ARVMs. Quantitative PCR data demonstrate that mRNA for dual specific AKAP1 and 2 (D-AKAP1 & D-AKAP2), acyl-CoA-binding domain-containing 3 (ACBD3), optic atrophy 1 (OPA1) are most abundant, while Rab32, WAVE-1, and sphingosine kinase type 1 interacting protein (SPHKAP) were barely detectable. Biochemical and immunocytochemical analysis suggests that D-AKAP1, D-AKAP2, and ACBD3 are the predominant mitochondrial AKAPs exposed to the cytosolic compartment in these cells. Furthermore, we show that both type I and type II regulatory subunits of PKA are associated with mitochondria. Taken together, these data suggest that D-AKAP1, D-AKAP2, and ACBD3 may be responsible for tethering both type I and type II PKA regulatory subunits to the outer mitochondrial membrane in ARVMs. In addition to regulating PKA-dependent mitochondrial function, these AKAPs may play an important role by buffering the movement of cAMP necessary for compartmentation.
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Affiliation(s)
| | - Chase Fiore
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
| | | | - Adam Wadsworth
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
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Rudokas MW, Post JP, Sataray-Rodriguez A, Sherpa RT, Moshal KS, Agarwal SR, Harvey RD. Compartmentation of β 2 -adrenoceptor stimulated cAMP responses by phosphodiesterase types 2 and 3 in cardiac ventricular myocytes. Br J Pharmacol 2021; 178:1574-1587. [PMID: 33475150 DOI: 10.1111/bph.15382] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 12/22/2020] [Accepted: 01/08/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE In cardiac myocytes, cyclic AMP (cAMP) produced by both β1 - and β2 -adrenoceptors increases L-type Ca2+ channel activity and myocyte contraction. However, only cAMP produced by β1 -adrenoceptors enhances myocyte relaxation through phospholamban-dependent regulation of the sarco/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2). Here we have tested the hypothesis that stimulation of β2 -adrenoceptors produces a cAMP signal that is unable to reach SERCA2 and determine what role, if any, phosphodiesterase (PDE) activity plays in this compartmentation. EXPERIMENTAL APPROACH The cAMP responses produced by β1 -and β2 -adrenoceptor stimulation were studied in adult rat ventricular myocytes using two different fluorescence resonance energy transfer (FRET)-based biosensors, the Epac2-camps, which is expressed uniformly throughout the cytoplasm of the entire cell and the Epac2-αKAP, which is targeted to the SERCA2 signalling complex. KEY RESULTS Selective activation of β1 - or β2 -adrenoceptors produced cAMP responses detected by Epac2-camps. However, only stimulation of β1 -adrenoceptors produced a cAMP response detected by Epac2-αKAP. Yet, stimulation of β2 -adrenoceptors was able to produce a cAMP signal detected by Epac2-αKAP in the presence of selective inhibitors of PDE2 or PDE3, but not PDE4. CONCLUSION AND IMPLICATIONS These results support the conclusion that cAMP produced by β2 -adrenoceptor stimulation was not able to reach subcellular locations where the SERCA2 pump is located. Furthermore, this compartmentalized response is due at least in part to PDE2 and PDE3 activity. This discovery could lead to novel PDE-based therapeutic treatments aimed at correcting cardiac relaxation defects associated with certain forms of heart failure.
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Affiliation(s)
| | - John P Post
- Department of Pharmacology, University of Nevada, Reno, Nevada, USA
| | | | - Rinzhin T Sherpa
- Department of Pharmacology, University of Nevada, Reno, Nevada, USA
| | - Karni S Moshal
- Department of Pharmacology, University of Nevada, Reno, Nevada, USA
| | | | - Robert D Harvey
- Department of Pharmacology, University of Nevada, Reno, Nevada, USA
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Rudokas MW, Post JP, Fiore CM, Agarwal SR, Harvey RD. Phosphodiesterase 2 and 3 Regulate Compartmentalized Beta2-Adrenergic Receptor Camp Signaling. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.3221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Nguyen HH, Law IH, Rudokas MW, Lampe J, Bowman TM, Van Hare GF, Avari Silva JN. Reveal LINQ Versus Reveal XT Implantable Loop Recorders: Intra- and Post-Procedural Comparison. J Pediatr 2017; 187:290-294. [PMID: 28545873 DOI: 10.1016/j.jpeds.2017.04.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/15/2017] [Accepted: 04/26/2017] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To compare the procedure, recovery, hospitalization times, and costs along with patient/parent satisfaction after newer-generation cardiac implantable loop recorder (Reveal LINQ; Medtronic Inc, Minneapolis, Minnesota) and previous-generation implantable loop recorder (Reveal XT; Medtronic Inc). STUDY DESIGN A prospective study of patients undergoing LINQ implantations between April 2014 and October 2015 was performed. Retrospective chart review of patients undergoing XT implantations was performed for comparison. RESULTS Thirty-one patients received LINQ and 15 patients received XT. Indications included syncope/palpitations (28/46, 61%), history of arrhythmias (9/46, 20%), arrhythmia burden in congenital heart disease (5/46, 10%), and monitoring in channelopathies (4/46, 9%). The LINQ group underwent more conscious sedation procedures than the XT group (8/31 vs 0/15, P = .04) with shorter procedural time (9 vs 34 minutes, P <.001), room occupation time (38 vs 81 minutes, P <.001), recovery time (21 vs 67 minutes, P <.001), and total hospital time (214 vs 264 minutes, P = .046). The LINQ group also had shorter return to activity time (2 vs 5 days, P = 1). Three device erosions in the LINQ group required reintervention. The LINQ group had fewer body image issues than the XT group (1/26 vs 5/14, P = .01) with both groups scoring 5/5 overall patient/parent satisfaction score at follow-up. Both groups had comparable total direct hospital costs (US $5905 vs $5438, P = .8). CONCLUSIONS LINQ offers better procedural and recovery time compared with XT. LINQ implantations under conscious sedation reduce total hospitalization time.
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Affiliation(s)
- Hoang H Nguyen
- Division of Cardiology, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Ian H Law
- Division of Cardiology, Department of Pediatrics, University of Iowa Carver School of Medicine, Iowa City, IA
| | - Michael W Rudokas
- Division of Cardiology, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Jennifer Lampe
- Division of Cardiology, Department of Pediatrics, University of Iowa Carver School of Medicine, Iowa City, IA
| | - Tammy M Bowman
- Division of Cardiology, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - George F Van Hare
- Division of Cardiology, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Jennifer N Avari Silva
- Division of Cardiology, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO.
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Rudokas MW, Varga Z, Schubert AR, Asaro AB, Silva JR. The Xenopus oocyte cut-open vaseline gap voltage-clamp technique with fluorometry. J Vis Exp 2014. [PMID: 24637712 DOI: 10.3791/51040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The cut-open oocyte Vaseline gap (COVG) voltage clamp technique allows for analysis of electrophysiological and kinetic properties of heterologous ion channels in oocytes. Recordings from the cut-open setup are particularly useful for resolving low magnitude gating currents, rapid ionic current activation, and deactivation. The main benefits over the two-electrode voltage clamp (TEVC) technique include increased clamp speed, improved signal-to-noise ratio, and the ability to modulate the intracellular and extracellular milieu. Here, we employ the human cardiac sodium channel (hNaV1.5), expressed in Xenopus oocytes, to demonstrate the cut-open setup and protocol as well as modifications that are required to add voltage clamp fluorometry capability. The properties of fast activating ion channels, such as hNaV1.5, cannot be fully resolved near room temperature using TEVC, in which the entirety of the oocyte membrane is clamped, making voltage control difficult. However, in the cut-open technique, isolation of only a small portion of the cell membrane allows for the rapid clamping required to accurately record fast kinetics while preventing channel run-down associated with patch clamp techniques. In conjunction with the COVG technique, ion channel kinetics and electrophysiological properties can be further assayed by using voltage clamp fluorometry, where protein motion is tracked via cysteine conjugation of extracellularly applied fluorophores, insertion of genetically encoded fluorescent proteins, or the incorporation of unnatural amino acids into the region of interest(1). This additional data yields kinetic information about voltage-dependent conformational rearrangements of the protein via changes in the microenvironment surrounding the fluorescent molecule.
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Affiliation(s)
- Michael W Rudokas
- Department of Biomedical Engineering, Washington University in St. Louis
| | - Zoltan Varga
- Department of Biomedical Engineering, Washington University in St. Louis
| | - Angela R Schubert
- Department of Biomedical Engineering, Washington University in St. Louis
| | - Alexandra B Asaro
- Department of Biomedical Engineering, Washington University in St. Louis
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St. Louis;
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