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Smith A, Auer D, Johnson M, Sanchez E, Ross H, Ward C, Chakravarti A, Kapoor A. Cardiac muscle-restricted partial loss of Nos1ap expression has limited but significant impact on electrocardiographic features. G3 (BETHESDA, MD.) 2023; 13:jkad208. [PMID: 37708408 PMCID: PMC10627271 DOI: 10.1093/g3journal/jkad208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 08/16/2023] [Accepted: 09/06/2023] [Indexed: 09/16/2023]
Abstract
Genome-wide association studies have identified sequence polymorphisms in a functional enhancer of the NOS1AP gene as the most common genetic regulator of QT interval and human cardiac NOS1AP gene expression in the general population. Functional studies based on in vitro overexpression in murine cardiomyocytes and ex vivo knockdown in zebrafish embryonic hearts, by us and others, have also demonstrated that NOS1AP expression levels can alter cellular electrophysiology. Here, to explore the role of NOS1AP in cardiac electrophysiology at an organismal level, we generated and characterized constitutive and heart muscle-restricted Nos1ap knockout mice to assess whether NOS1AP disruption alters the QT interval in vivo. Constitutive loss of Nos1ap led to genetic background-dependent variable lethality at or right before birth. Heart muscle-restricted Nos1ap knockout, generated using cardiac-specific alpha-myosin heavy chain promoter-driven tamoxifen-inducible Cre, resulted in tissue-level Nos1ap expression reduced by half. This partial loss of expression had no detectable effect on the QT interval or other electrocardiographic and echocardiographic parameters, except for a small but significant reduction in the QRS interval. Given that challenges associated with defining the end of the T wave on murine electrocardiogram can limit identification of subtle effects on the QT interval and that common noncoding NOS1AP variants are also associated with the QRS interval, our findings support the role of NOS1AP in regulation of the cardiac electrical cycle.
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Affiliation(s)
- Alexa Smith
- Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Dallas Auer
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Morgan Johnson
- Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ernesto Sanchez
- Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Holly Ross
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christopher Ward
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Aravinda Chakravarti
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Center for Human Genetics and Genomics, New York University School of Medicine, New York, NY 10016, USA
| | - Ashish Kapoor
- Institute of Molecular Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Hernandez K, Swiatkowski P, Patel MV, Liang C, Dudzinski NR, Brzustowicz LM, Firestein BL. Overexpression of Isoforms of Nitric Oxide Synthase 1 Adaptor Protein, Encoded by a Risk Gene for Schizophrenia, Alters Actin Dynamics and Synaptic Function. Front Cell Neurosci 2016; 10:6. [PMID: 26869880 PMCID: PMC4735351 DOI: 10.3389/fncel.2016.00006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/11/2016] [Indexed: 11/13/2022] Open
Abstract
Proper communication between neurons depends upon appropriate patterning of dendrites and correct distribution and structure of spines. Schizophrenia is a neuropsychiatric disorder characterized by alterations in dendrite branching and spine density. Nitric oxide synthase 1 adaptor protein (NOS1AP), a risk gene for schizophrenia, encodes proteins that are upregulated in the dorsolateral prefrontal cortex (DLPFC) of individuals with schizophrenia. To elucidate the effects of NOS1AP overexpression observed in individuals with schizophrenia, we investigated changes in actin dynamics and spine development when a long (NOS1AP-L) or short (NOS1AP-S) isoform of NOS1AP is overexpressed. Increased NOS1AP-L protein promotes the formation of immature spines when overexpressed in rat cortical neurons from day in vitro (DIV) 14 to DIV 17 and reduces the amplitude of miniature excitatory postsynaptic currents (mEPSCs). In contrast, increased NOS1AP-S protein increases the rate of actin polymerization and the number of immature and mature spines, which may be attributed to a decrease in total Rac1 expression and a reduction in the levels of active cofilin. The increase in the number of mature spines by overexpression of NOS1AP-S is accompanied by an increase in the frequency of mEPSCs. Our findings show that overexpression of NOS1AP-L or NOS1AP-S alters the actin cytoskeleton and synaptic function. However, the mechanisms by which these isoforms induce these changes are distinct. These results are important for understanding how increased expression of NOS1AP isoforms can influence spine development and synaptic function.
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Affiliation(s)
- Kristina Hernandez
- Department of Cell Biology and Neuroscience, Human Genetics Institute of New Jersey, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Przemyslaw Swiatkowski
- Department of Cell Biology and Neuroscience, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Mihir V. Patel
- Department of Cell Biology and Neuroscience, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Chen Liang
- Department of Cell Biology and Neuroscience, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Natasha R. Dudzinski
- Department of Cell Biology and Neuroscience, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Linda M. Brzustowicz
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers—The State University of New JerseyPiscataway, NJ, USA
| | - Bonnie L. Firestein
- Department of Cell Biology and Neuroscience, Human Genetics Institute of New Jersey, Rutgers—The State University of New JerseyPiscataway, NJ, USA
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