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Park NK, Park SJ, Park YG, Moon SH, Woo J, Kim HJ, Kim SJ, Choi SW. Translation reinitiation in c.453delC frameshift mutation of KCNH2 producing functional hERG K+ channels with mild dominant negative effect in the heterozygote patient-derived iPSC cardiomyocytes. Hum Mol Genet 2024; 33:110-121. [PMID: 37769355 DOI: 10.1093/hmg/ddad165] [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: 03/16/2023] [Revised: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 09/30/2023] Open
Abstract
The c.453delC (p.Thr152Profs*14) frameshift mutation in KCNH2 is associated with an elevated risk of Long QT syndrome (LQTS) and fatal arrhythmia. Nevertheless, the loss-of-function mechanism underlying this mutation remains unexplored and necessitates an understanding of electrophysiology. To gain insight into the mechanism of the LQT phenotype, we conducted whole-cell patch-clamp and immunoblot assays, utilizing both a heterologous expression system and patient-derived induced pluripotent stem cell-cardiomyocytes (iPSC-CMs) with 453delC-KCNH2. We also explored the site of translational reinitiation by employing LC/MS mass spectrometry. Contrary to the previous assumption of early termination of translation, the findings of this study indicate that the 453delC-KCNH2 leads to an N-terminally truncated hERG channel, a potential from a non-canonical start codon, with diminished expression and reduced current (IhERG). The co-expression with wildtype KCNH2 produced heteromeric hERG channel with mild dominant-negative effect. Additionally, the heterozygote patient-derived iPSC-CMs exhibited prolonged action potential duration and reduced IhERG, which was ameliorated with the use of a hERG activator, PD-118057. The results of our study offer novel insights into the mechanisms involved in congenital LQTS associated with the 453delC mutation of KCNH2. The mutant results in the formation of less functional N-terminal-truncated channels with reduced amount of membrane expression. A hERG activator is capable of correcting abnormalities in both the heterologous expression system and patient-derived iPSC-CMs.
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Affiliation(s)
- Na Kyeong Park
- Department of Physiology, Seoul National University College of Medicine, 103, Daehak-ro, Seoul 03080, Korea
| | - Soon-Jung Park
- Stem Cell Research Institute, T&R Biofab Co. Ltd, 237, Sangidaehak-ro, Siheung 15073, Korea
| | - Yun-Gwi Park
- Department of Animal Science and Technology, Chung-Ang University, 4726, Seodong-daero, Anseong 17546, Korea
| | - Sung-Hwan Moon
- Department of Animal Science and Technology, Chung-Ang University, 4726, Seodong-daero, Anseong 17546, Korea
| | - JooHan Woo
- Department of Physiology, Dongguk University College of Medicine, 123, Dongdae-ro, Gyeongju 38066, Korea
| | - Hyun Jong Kim
- Department of Physiology, Dongguk University College of Medicine, 123, Dongdae-ro, Gyeongju 38066, Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, 103, Daehak-ro, Seoul 03080, Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 103, Daehak-ro, Seoul 03080, Korea
| | - Seong Woo Choi
- Department of Physiology, Dongguk University College of Medicine, 123, Dongdae-ro, Gyeongju 38066, Korea
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Bayaraa O, Dashnyam K, Singh RK, Mandakhbayar N, Lee JH, Park JT, Lee JH, Kim HW. Nanoceria-GO-intercalated multicellular spheroids revascularize and salvage critical ischemic limbs through anti-apoptotic and pro-angiogenic functions. Biomaterials 2023; 292:121914. [PMID: 36436306 DOI: 10.1016/j.biomaterials.2022.121914] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 11/15/2022]
Abstract
Critical limb ischemia (CLI) is a serious form of peripheral arterial disease that involves severe blockage of blood flow in lower extremities, often leading to foot necrosis and limb loss. Lack of blood flow and high pro-inflammation with overproduced reactive oxygen species (ROS) in CLI aggravate the degenerative events. Among other therapies, cell delivery is considered potential for restoring regenerative capacity, and preservation of cell survival under high oxidative stress has been challenging and prerequisite to harness cellular functions. Here, we introduce a multicellular delivery system that is intercalated with nanoceria-decorated graphene oxide (CeGO), which is considered to have high ROS scavenging ability while providing cell-matrix interaction signals. The CeGO nano-microsheets (8-nm-nanoceria/0.9-μm-GO) incorporated in HUVEC/MSC (7/3) could form cell-material hybrid spheroids mediated by cellular contraction. Under in vitro oxidative-stress-challenge with H2O2, the CeGO-intercalation enhanced the survival and anti-apoptotic capacity of cellular spheroids. Pro-angiogenic events of cellular spheroids, including cell sprouting and expression of angiogenic markers (HIF1α, VEGF, FGF2, eNOS) were significantly enhanced by the CeGO-intercalation. Proteomics analysis also confirmed substantial up-regulation of a series of angiogenesis-related secretome molecules. Such pro-angiogenic events with CeGO-intercalation were proven to be mediated by the APE/Ref-1 signaling pathway. When delivered to ischemic hindlimb in mice, the CeGO-cell spheroids could inhibit the accumulation of in vivo ROS rapidly, preserving high cell survival rate (cells were more proliferative and less apoptotic vs. those in cell-only spheroids), and up-regulated angiogenic molecular expressions. Monitoring over 28 days revealed significantly enhanced blood reperfusion and tissue recovery, and an ultimate limb salvage with the CeGO-cell delivery (∼60% salvaged vs. ∼29% in cell-only delivery vs. 0% in ischemia control). Together, the CeGO intercalated in HUVEC/MSC delivery is considered a potential nano-microplatform for CLI treatment, by scavenging excessive ROS and enhancing transplanted cell survival, while stimulating angiogenic events, which collectively help revascularization and tissue recovery, salvaging critical ischemic limbs.
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Affiliation(s)
- Oyunchimeg Bayaraa
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea; Drug Research Institute, Mongolian University of Pharmaceutical Science, 14250, Mongolia
| | - Khandmaa Dashnyam
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Drug Research Institute, Mongolian University of Pharmaceutical Science, 14250, Mongolia
| | - Rajendra K Singh
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Nandin Mandakhbayar
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jun Hee Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea; Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea; Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jong-Tae Park
- Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea; Department of Oral Anatomy, College of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea
| | - Jung-Hwan Lee
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea; Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea; Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea; Cell & Matter Institute, Dankook University, Cheonan, 31116, Republic of Korea; UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, Cheonan, 31116, Republic of Korea
| | - Hae-Won Kim
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan, 31116, Republic of Korea; Department of Nanobiomedical Science and BK21 NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan, 31116, Republic of Korea; Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan, 31116, Republic of Korea; Mechanobiology Dental Medicine Research Center, Dankook University, Cheonan, 31116, Republic of Korea; Cell & Matter Institute, Dankook University, Cheonan, 31116, Republic of Korea; UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, Cheonan, 31116, Republic of Korea.
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