Pub Date : 2022-07-01Epub Date: 2022-05-24DOI: 10.1016/j.jbc.2022.102070
Tianbang Wang, Emrulla Spahiu, Jennifer Osten, Florentine Behrens, Fabius Grünhagen, Tim Scholz, Theresia Kraft, Arnab Nayak, Mamta Amrute-Nayak
The myosin II motors are ATP-powered force-generating machines driving cardiac and muscle contraction. Myosin II heavy chain isoform-beta (β-MyHC) is primarily expressed in the ventricular myocardium and in slow-twitch muscle fibers, such as M. soleus. M. soleus-derived myosin II (SolM-II) is often used as an alternative to the ventricular β-cardiac myosin (βM-II); however, the direct assessment of biochemical and mechanical features of the native myosins is limited. By employing optical trapping, we examined the mechanochemical properties of native myosins isolated from the rabbit heart ventricle and soleus muscles at the single-molecule level. We found purified motors from the two tissue sources, despite expressing the same MyHC isoform, displayed distinct motile and ATPase kinetic properties. We demonstrate βM-II was approximately threefold faster in the actin filament-gliding assay than SolM-II. The maximum actomyosin (AM) detachment rate derived in single-molecule assays was also approximately threefold higher in βM-II, while the power stroke size and stiffness of the "AM rigor" crossbridge for both myosins were comparable. Our analysis revealed a higher AM detachment rate for βM-II, corresponding to the enhanced ADP release rates from the crossbridge, likely responsible for the observed differences in the motility driven by these myosins. Finally, we observed a distinct myosin light chain 1 isoform (MLC1sa) that associates with SolM-II, which might contribute to the observed kinetics differences between βM-II and SolM-II. These results have important implications for the choice of tissue sources and justify prerequisites for the correct myosin heavy and light chains to study cardiomyopathies.
肌球蛋白 II 马达是以 ATP 为动力的力量生成器，驱动着心脏和肌肉收缩。肌球蛋白 II 重链异构体-β（β-MyHC）主要在心室心肌和比目鱼肌等慢肌纤维中表达。源自比目鱼肌的肌球蛋白 II（SolM-II）经常被用作心室β-心肌肌球蛋白（βM-II）的替代物；然而，对原生肌球蛋白的生化和机械特征的直接评估却很有限。通过采用光学捕获技术，我们在单分子水平上研究了从兔心室肌和比目鱼肌中分离出来的原生肌球蛋白的机械化学特性。我们发现，尽管这两种组织来源的纯化肌球蛋白表达相同的 MyHC 异构体，但其运动和 ATPase 动力特性却截然不同。我们证明在肌动蛋白丝滑动试验中，βM-II 比 SolM-II 快约三倍。在单分子测定中得出的最大肌动蛋白（AM）分离速率也是βM-II的约三倍，而两种肌球蛋白的 "AM刚性 "横桥的动力冲程大小和硬度相当。我们的分析表明，βM-II 的 AM 分离率更高，这与交桥中 ADP 释放率的提高相对应，这可能是观察到的这些肌球蛋白驱动的运动差异的原因。最后，我们观察到一种与 SolM-II 结合的独特肌球蛋白轻链 1 异构体（MLC1sa），这可能是导致观察到的 βM-II 和 SolM-II 动力学差异的原因。这些结果对组织来源的选择具有重要意义，并证明了正确的肌球蛋白重链和轻链是研究心肌病的先决条件。
{"title":"Cardiac ventricular myosin and slow skeletal myosin exhibit dissimilar chemomechanical properties despite bearing the same myosin heavy chain isoform.","authors":"Tianbang Wang, Emrulla Spahiu, Jennifer Osten, Florentine Behrens, Fabius Grünhagen, Tim Scholz, Theresia Kraft, Arnab Nayak, Mamta Amrute-Nayak","doi":"10.1016/j.jbc.2022.102070","DOIUrl":"10.1016/j.jbc.2022.102070","url":null,"abstract":"<p><p>The myosin II motors are ATP-powered force-generating machines driving cardiac and muscle contraction. Myosin II heavy chain isoform-beta (β-MyHC) is primarily expressed in the ventricular myocardium and in slow-twitch muscle fibers, such as M. soleus. M. soleus-derived myosin II (SolM-II) is often used as an alternative to the ventricular β-cardiac myosin (βM-II); however, the direct assessment of biochemical and mechanical features of the native myosins is limited. By employing optical trapping, we examined the mechanochemical properties of native myosins isolated from the rabbit heart ventricle and soleus muscles at the single-molecule level. We found purified motors from the two tissue sources, despite expressing the same MyHC isoform, displayed distinct motile and ATPase kinetic properties. We demonstrate βM-II was approximately threefold faster in the actin filament-gliding assay than SolM-II. The maximum actomyosin (AM) detachment rate derived in single-molecule assays was also approximately threefold higher in βM-II, while the power stroke size and stiffness of the \"AM rigor\" crossbridge for both myosins were comparable. Our analysis revealed a higher AM detachment rate for βM-II, corresponding to the enhanced ADP release rates from the crossbridge, likely responsible for the observed differences in the motility driven by these myosins. Finally, we observed a distinct myosin light chain 1 isoform (MLC1sa) that associates with SolM-II, which might contribute to the observed kinetics differences between βM-II and SolM-II. These results have important implications for the choice of tissue sources and justify prerequisites for the correct myosin heavy and light chains to study cardiomyopathies.</p>","PeriodicalId":22153,"journal":{"name":"Surgical Neurology","volume":"22 1","pages":"102070"},"PeriodicalIF":0.0,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9243179/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75522220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A case of Moyamoya disease is discussed, presenting in a young adult with subarachnoid hemorrhage. Moyamoya is a rare form of crebro-vascular occlusive disease, characterized by specific arteriographic findings. The etiology of the disorder is unknown.
{"title":"Moyamoya disease.","authors":"J. Dillion, H. Stokes, A. Meirowsky","doi":"10.32388/uejoi3","DOIUrl":"https://doi.org/10.32388/uejoi3","url":null,"abstract":"A case of Moyamoya disease is discussed, presenting in a young adult with subarachnoid hemorrhage. Moyamoya is a rare form of crebro-vascular occlusive disease, characterized by specific arteriographic findings. The etiology of the disorder is unknown.","PeriodicalId":22153,"journal":{"name":"Surgical Neurology","volume":"3 5 1","pages":"233-6"},"PeriodicalIF":0.0,"publicationDate":"2020-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43525303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-05-01Epub Date: 2016-01-08DOI: 10.1016/j.msec.2016.01.012
Tao Wu, Lei Tan, Ning Cheng, Qi Yan, Yu-Feng Zhang, Chuan-Jun Liu, Bin Shi
This work presented a sustained release system of simvastatin (SIM) based on the mesoporous hydroxyapatite (MHA) capped with poly(N-isopropylacrylamide) (PNIPAAM). The MHA was prepared by using cetyltrimethylammonium bromide (CTAB) as a template and the modified PNIPAAM layer on the surface of MHA was fabricated through surface-initiated atom transfer radical polymerization (SI-ATRP). The SIM loaded MHA-PNIPAAM showed a sustained release of SIM at 37 °C over 16 days. The bone marrow mesenchymal stem cell (BMSC) proliferation was assessed by cell counting kit-8 (CCK-8) assay, and the osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity and Alizarin Red staining. The release profile showed that the release of SIM from MHA-SIM-PNIPAAM lasted 16 days and the cumulative amount of released SIM was almost seven-fold than MHA-SIM. Besides, SIM loaded MHA-PNIPAAM exhibited better performance on cell proliferation, ALP activity, and calcium deposition than pure MHA due to the sustained release of SIM. The quantity of ALP in MHA-SIM-PNIPAAM group was more than two fold than pure MHA group at 7 days. Compared to pure MHA, better BMSC attachment on PNIPAAM modified MHA was observed using fluorescent microscopy, indicating the better biocompatibility of MHA-PNIPAAM.
{"title":"PNIPAAM modified mesoporous hydroxyapatite for sustained osteogenic drug release and promoting cell attachment.","authors":"Tao Wu, Lei Tan, Ning Cheng, Qi Yan, Yu-Feng Zhang, Chuan-Jun Liu, Bin Shi","doi":"10.1016/j.msec.2016.01.012","DOIUrl":"10.1016/j.msec.2016.01.012","url":null,"abstract":"<p><p>This work presented a sustained release system of simvastatin (SIM) based on the mesoporous hydroxyapatite (MHA) capped with poly(N-isopropylacrylamide) (PNIPAAM). The MHA was prepared by using cetyltrimethylammonium bromide (CTAB) as a template and the modified PNIPAAM layer on the surface of MHA was fabricated through surface-initiated atom transfer radical polymerization (SI-ATRP). The SIM loaded MHA-PNIPAAM showed a sustained release of SIM at 37 °C over 16 days. The bone marrow mesenchymal stem cell (BMSC) proliferation was assessed by cell counting kit-8 (CCK-8) assay, and the osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity and Alizarin Red staining. The release profile showed that the release of SIM from MHA-SIM-PNIPAAM lasted 16 days and the cumulative amount of released SIM was almost seven-fold than MHA-SIM. Besides, SIM loaded MHA-PNIPAAM exhibited better performance on cell proliferation, ALP activity, and calcium deposition than pure MHA due to the sustained release of SIM. The quantity of ALP in MHA-SIM-PNIPAAM group was more than two fold than pure MHA group at 7 days. Compared to pure MHA, better BMSC attachment on PNIPAAM modified MHA was observed using fluorescent microscopy, indicating the better biocompatibility of MHA-PNIPAAM.</p>","PeriodicalId":22153,"journal":{"name":"Surgical Neurology","volume":"42 1","pages":"888-96"},"PeriodicalIF":7.9,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995466/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75546487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-01DOI: 10.1016/j.surneu.2009.02.002
Paul S. Slosberg MD
{"title":"Re: The neuroprotective effect of dexmedetomidine in the hippocampus of rabbits after subarachnoid hemorrhage (Cosar et al. Surg Neurol 2009;71:54-59)","authors":"Paul S. Slosberg MD","doi":"10.1016/j.surneu.2009.02.002","DOIUrl":"10.1016/j.surneu.2009.02.002","url":null,"abstract":"","PeriodicalId":22153,"journal":{"name":"Surgical Neurology","volume":"72 6","pages":"Pages 648-649"},"PeriodicalIF":0.0,"publicationDate":"2009-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.surneu.2009.02.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28386015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-01DOI: 10.1016/j.wneu.2009.11.001
James I. Ausman MD, PhD ((Editor))
{"title":"Addendum to “In this issue…”","authors":"James I. Ausman MD, PhD ((Editor))","doi":"10.1016/j.wneu.2009.11.001","DOIUrl":"10.1016/j.wneu.2009.11.001","url":null,"abstract":"","PeriodicalId":22153,"journal":{"name":"Surgical Neurology","volume":"72 6","pages":"Page 651"},"PeriodicalIF":0.0,"publicationDate":"2009-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.wneu.2009.11.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"28654353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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