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Bovo E, Jamrozik T, Kahn D, Karkut P, Robia SL, Zima AV. Phosphorylation of phospholamban promotes SERCA2a activation by dwarf open reading frame (DWORF). Cell Calcium 2024; 121:102910. [PMID: 38823350 PMCID: PMC11247691 DOI: 10.1016/j.ceca.2024.102910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/03/2024]
Abstract
In cardiac myocytes, the type 2a sarco/endoplasmic reticulum Ca-ATPase (SERCA2a) plays a key role in intracellular Ca regulation. Due to its critical role in heart function, SERCA2a activity is tightly regulated by different mechanisms, including micropeptides. While phospholamban (PLB) is a well-known SERCA2a inhibitor, dwarf open reading frame (DWORF) is a recently identified SERCA2a activator. Since PLB phosphorylation is the most recognized mechanism of SERCA2a activation during adrenergic stress, we studied whether PLB phosphorylation also affects SERCA2a regulation by DWORF. By using confocal Ca imaging in a HEK293 expressing cell system, we analyzed the effect of the co-expression of PLB and DWORF using a bicistronic construct on SERCA2a-mediated Ca uptake. Under these conditions of matched expression of PLB and DWORF, we found that SERCA2a inhibition by non-phosphorylated PLB prevails over DWORF activating effect. However, when PLB is phosphorylated at PKA and CaMKII sites, not only PLB's inhibitory effect was relieved, but SERCA2a was effectively activated by DWORF. Förster resonance energy transfer (FRET) analysis between SERCA2a and DWORF showed that DWORF has a higher relative affinity for SERCA2a when PLB is phosphorylated. Thus, SERCA2a regulation by DWORF responds to the PLB phosphorylation status, suggesting that DWORF might contribute to SERCA2a activation during conditions of adrenergic stress.
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Affiliation(s)
- Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA.
| | - Thomas Jamrozik
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA
| | - Daniel Kahn
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA
| | - Patryk Karkut
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Avenue, Maywood, IL 60153, USA
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Stege NM, Oliveira Nunes Teixeira V, Zijlstra SN, Feringa AM, de Boer RA, Silljé HHW. Deletion of DWORF does not affect cardiac function in aging and in PLN-R14del cardiomyopathy. Am J Physiol Heart Circ Physiol 2024; 326:H870-H876. [PMID: 38334971 PMCID: PMC11221797 DOI: 10.1152/ajpheart.00741.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 02/10/2024]
Abstract
The phospholamban (PLN) pathogenic gene variant p.Arg14del causes cardiomyopathy, which is characterized by perinuclear PLN protein clustering and can lead to severe heart failure (HF). Elevated expression of dwarf open reading frame (DWORF), a protein counteracting the function of PLN in the sarcoplasmic reticulum (SR), can delay disease progression in a PLN-R14del mouse model. Here, we evaluated whether deletion of DWORF (DWORF-/-) would have an opposite effect and accelerate age-dependent disease progression in wild-type (WT) mice and mice with a pathogenic PLN-R14del allele (R14Δ/+). We show that DWORF-/- mice maintained a normal left ventricular ejection fraction (LVEF) during aging and no difference with WT control mice could be observed up to 20 mo of age. R14Δ/+ mice maintained a normal cardiac function until 12 mo of age, but at 18 mo of age, LVEF was significantly reduced as compared with WT mice. Absence of DWORF did neither accelerate the R14Δ/+-induced reduction in LVEF nor enhance the increases in gene expression of markers related to cardiac remodeling and fibrosis and did not exacerbate cardiac fibrosis caused by the R14Δ/+ mutation. Together, these results demonstrate that absence of DWORF does not accelerate or exacerbate PLN-R14del cardiomyopathy in mice harboring the pathogenic R14del allele. In addition, our data indicate that DWORF appears to be dispensable for cardiac function during aging.NEW & NOTEWORTHY Although DWORF overexpression significantly delayed heart failure development and strongly prolonged life span in PLN-R14del mice, the current study shows that deletion of DWORF does not accelerate or exacerbate PLN-R14del cardiomyopathy in mice harboring the pathogenic R14del allele. In addition, DWORF appears to be dispensable for cardiac function during aging. Changes in DWORF gene expression are therefore unlikely to contribute to the clinical heterogeneity observed in patients with PLN-R14del cardiomyopathy.
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Affiliation(s)
- Nienke M Stege
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | | | - Sietske N Zijlstra
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Anna M Feringa
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Rudolf A de Boer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Erasmus MC, Cardiovascular Institute, Thorax Center, Department of Cardiology, Rotterdam, The Netherlands
| | - Herman H W Silljé
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Lairez O, Fournier P, Itier R, Bachelet B, Huart A, Cariou E. Towards etiological treatments in cardiomyopathies. Presse Med 2024; 53:104223. [PMID: 38309622 DOI: 10.1016/j.lpm.2024.104223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/05/2024] Open
Abstract
This review proposes to look at the evolution of cardiomyopathy treatments in the light of advances in diagnostic techniques, which have enabled to move from a mechanistic to a phenotypic and then etiological approach. The article goes beyond the ejection fraction approach, and look at new therapies that target the pathophysiological pathways of cardiomyopathies, either by targeting the phenotype, or by targeting the etiology. The evolution of HCM treatments is detailed, culminating in the latest etiological treatments such as mavacamten in sarcomeric HCM, tafamidis in transthyretin cardiac amyloidosis and migalastat in Fabry disease. Myosin stimulators are reviewed in the treatment of DCM, before opening perspectives for gene therapy, which proposes direct treatment of the culprit mutation.
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Affiliation(s)
- Olivier Lairez
- Department of Cardiology, Toulouse University Hospital, Toulouse, France; Cardiac Imaging Center, Toulouse University Hospital, Toulouse, France; Department of Nuclear Medicine, Toulouse University Hospital, France; Medical School, Toulouse III Paul Sabatier University, Toulouse, France.
| | - Pauline Fournier
- Department of Cardiology, Toulouse University Hospital, Toulouse, France; Cardiac Imaging Center, Toulouse University Hospital, Toulouse, France
| | - Romain Itier
- Department of Cardiology, Toulouse University Hospital, Toulouse, France; Cardiac Imaging Center, Toulouse University Hospital, Toulouse, France
| | - Bérengère Bachelet
- Department of Cardiology, Toulouse University Hospital, Toulouse, France
| | - Antoine Huart
- Department of Nephrology and Organ Transplantation, Toulouse University Hospital, Toulouse, France
| | - Eve Cariou
- Department of Cardiology, Toulouse University Hospital, Toulouse, France; Cardiac Imaging Center, Toulouse University Hospital, Toulouse, France
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Maniezzi C, Eskandr M, Florindi C, Ferrandi M, Barassi P, Sacco E, Pasquale V, Maione AS, Pompilio G, Teixeira VON, de Boer RA, Silljé HHW, Lodola F, Zaza A. Early consequences of the phospholamban mutation PLN-R14del +/- in a transgenic mouse model. Acta Physiol (Oxf) 2024; 240:e14082. [PMID: 38214033 DOI: 10.1111/apha.14082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 12/11/2023] [Accepted: 01/01/2024] [Indexed: 01/13/2024]
Abstract
AIMS The heterozygous phospholamban (PLN) mutation R14del (PLN R14del+/- ) is associated with a severe arrhythmogenic cardiomyopathy (ACM) developing in the adult. "Superinhibition" of SERCA2a by PLN R14del is widely assumed to underlie the pathogenesis, but alternative mechanisms such abnormal energy metabolism have also been reported. This work aims to (1) to evaluate Ca2+ dynamics and energy metabolism in a transgenic (TG) mouse model of the mutation prior to cardiomyopathy development; (2) to test whether they are causally connected. METHODS Ca2+ dynamics, energy metabolism parameters, reporters of mitochondrial integrity, energy, and redox homeostasis were measured in ventricular myocytes of 8-12 weeks-old, phenotypically silent, TG mice. Mutation effects were compared to pharmacological PLN antagonism and analyzed during modulation of sarcoplasmic reticulum (SR) and cytosolic Ca2+ compartments. Transcripts and proteins of relevant signaling pathways were evaluated. RESULTS The mutation was characterized by hyperdynamic Ca2+ handling, compatible with a loss of SERCA2a inhibition by PLN. All components of energy metabolism were depressed; myocyte energy charge was preserved under quiescence but reduced during stimulation. Cytosolic Ca2+ buffering or SERCA2a blockade reduced O2 consumption with larger effect in the mutant. Signaling changes suggest cellular adaptation to perturbed Ca2+ dynamics and response to stress. CONCLUSIONS (1) PLN R14del+/- loses its ability to inhibit SERCA2a, which argues against SERCA2a superinhibition as a pathogenetic mechanism; (2) depressed energy metabolism, its enhanced dependency on Ca2+ and activation of signaling responses point to an early involvement of metabolic stress in the pathogenesis of this ACM model.
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Affiliation(s)
- Claudia Maniezzi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Marem Eskandr
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Chiara Florindi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Mara Ferrandi
- Windtree Therapeutics Inc., Warrington, Pennsylvania, USA
| | - Paolo Barassi
- Windtree Therapeutics Inc., Warrington, Pennsylvania, USA
| | - Elena Sacco
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Valentina Pasquale
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Angela S Maione
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino IRCCS, Milan, Italy
| | - Giulio Pompilio
- Unit of Vascular Biology and Regenerative Medicine, Centro Cardiologico Monzino IRCCS, Milan, Italy
- Department of Biomedical, Surgical and Dentist Sciences, University of Milano, Milan, Italy
| | | | - Rudolf A de Boer
- Department of Cardiology, Erasmus University Medical Center, University of Rotterdam, Rotterdam, Netherlands
| | - Herman H W Silljé
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Francesco Lodola
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
| | - Antonio Zaza
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Milan, Italy
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