16 results on '"Smith III, John E."'
Search Results
2. Correction to: Expressing a Z-disk nebulin fragment innebulin-deficient mouse muscle: effects on muscle structure and function
- Author
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Li, Frank, Kolb, Justin, Crudele, Julie, Tonino, Paola, Hourani, Zaynab, Smith, III, John E., Chamberlain, Jeffrey S., and Granzier, Henk
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- 2020
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3. Expressing a Z-disk nebulin fragment in nebulin-deficient mouse muscle: effects on muscle structure and function
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Li, Frank, Kolb, Justin, Crudele, Julie, Tonino, Paola, Hourani, Zaynab, Smith, III, John E., Chamberlain, Jeffrey S., and Granzier, Henk
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- 2020
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4. Novex-3, the tiny titin of muscle
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Kellermayer, Dalma, Smith, III, John E., and Granzier, Henk
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- 2017
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5. In vivo gene editing of CAMKIID: out with the bad and in with the good.
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Smith III, John E. and Granzier, Henk
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The ability to change an organism's DNA through gene editing is of great importance for the prevention and treatment of genetic and acquired diseases. Rapid progress has been made during the last decade due to the discovery and refinement of CRISPR/Cas9 as an accurate, fast, and reliable genome editing technique. In this issue of the JCI, Lebek et al. present the culmination from a line of work in the Olson laboratory focused on in vivo gene editing of CAMK2D. The paper presents a combined state-of-the-art gene therapy approach that demonstrates how gene therapy can yield cardioprotection in a mouse model and takes notable steps toward potential applicability in patients. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Single-Molecule Force Spectroscopy on the N2A Element of Titin: Effects of Phosphorylation and CARP
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Lanzicher, Thomas, primary, Zhou, Tiankun, additional, Saripalli, Chandra, additional, Keschrumrus, Vic, additional, Smith III, John E., additional, Mayans, Olga, additional, Sbaizero, Orfeo, additional, and Granzier, Henk, additional
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- 2020
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7. Congenital Titinopathy: Comprehensive characterization and pathogenic insights.
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Oates, Emily C., Jones, Kristi J., Donkervoort, Sandra, Charlton, Amanda, Brammah, Susan, Smith III, John E., Ware, James S., Yau, Kyle S., Swanson, Lindsay C., Whiffin, Nicola, Peduto, Anthony J., Bournazos, Adam, Waddell, Leigh B., Farrar, Michelle A., Sampaio, Hugo A., Teoh, Hooi Ling, Lamont, Phillipa J., Mowat, David, Fitzsimons, Robin B., and Corbett, Alastair J.
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CONGENITAL disorders ,EXTREMITIES (Anatomy) ,SCOLIOSIS ,MUSCLE hypotonia ,CREATINE kinase ,PATIENTS - Abstract
Objective: Comprehensive clinical characterization of congenital titinopathy to facilitate diagnosis and management of this important emerging disorder.Methods: Using massively parallel sequencing we identified 30 patients from 27 families with 2 pathogenic nonsense, frameshift and/or splice site TTN mutations in trans. We then undertook a detailed analysis of the clinical, histopathological and imaging features of these patients.Results: All patients had prenatal or early onset hypotonia and/or congenital contractures. None had ophthalmoplegia. Scoliosis and respiratory insufficiency typically developed early and progressed rapidly, whereas limb weakness was often slowly progressive, and usually did not prevent independent walking. Cardiac involvement was present in 46% of patients. Relatives of 2 patients had dilated cardiomyopathy. Creatine kinase levels were normal to moderately elevated. Increased fiber size variation, internalized nuclei and cores were common histopathological abnormalities. Cap-like regions, whorled or ring fibers, and mitochondrial accumulations were also observed. Muscle magnetic resonance imaging showed gluteal, hamstring and calf muscle involvement. Western blot analysis showed a near-normal sized titin protein in all samples. The presence of 2 mutations predicted to impact both N2BA and N2B cardiac isoforms appeared to be associated with greatest risk of cardiac involvement. One-third of patients had 1 mutation predicted to impact exons present in fetal skeletal muscle, but not included within the mature skeletal muscle isoform transcript. This strongly suggests developmental isoforms are involved in the pathogenesis of this congenital/early onset disorder.Interpretation: This detailed clinical reference dataset will greatly facilitate diagnostic confirmation and management of patients, and has provided important insights into disease pathogenesis. Ann Neurol 2018;83:1105-1124. [ABSTRACT FROM AUTHOR]- Published
- 2018
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8. The giant protein titin regulates the length of the striated muscle thick filament.
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Tonino, Paola, Kiss, Balazs, Strom, Josh, Methawasin, Mei, Smith III, John E., Kolb, Justin, Labeit, Siegfried, and Granzier, Henk
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STRIATED muscle ,CONNECTIN ,MOLECULAR motor proteins ,MYOCARDIUM ,FIBERS ,SKELETAL muscle - Abstract
The contractile machinery of heart and skeletal muscles has as an essential component the thick filament, comprised of the molecular motor myosin. The thick filament is of a precisely controlled length, defining thereby the force level that muscles generate and how this force varies with muscle length. It has been speculated that the mechanism by which thick filament length is controlled involves the giant protein titin, but no conclusive support for this hypothesis exists. Here we show that in a mouse model in which we deleted two of titin’s C-zone super-repeats, thick filament length is reduced in cardiac and skeletal muscles. In addition, functional studies reveal reduced force generation and a dilated cardiomyopathy (DCM) phenotype. Thus, regulation of thick filament length depends on titin and is critical for maintaining muscle health. [ABSTRACT FROM AUTHOR]
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- 2017
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9. Experimentally Increasing Titin Compliance in a Novel Mouse Model Attenuates the Frank-Starling Mechanism but has a Beneficial Effect on Diastole
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Methawasin, Mei, Hutchinson, Kirk R., Lee, Eun-Jeong, Smith III, John E., Saripalli, Chandra, Hidalgo, Carlos G., and Granzier, Henk L.
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cardiovascular system ,Biophysics - Published
- 2014
10. Nebulin deficiency in adult muscle causes sarcomere defects and muscle-type-dependent changes in trophicity: novel insights in nemaline myopathy.
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Li, Frank, Buck, Danielle, De Winter, Josine, Kolb, Justin, Hui Meng, Birch, Camille, Slater, Rebecca, Natelie Escobar, Yael, Smith III, John E., Lin Yang, Konhilas, John, Lawlor, Michael W., Ottenheijm, Coen, and Granzier, Henk L.
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- 2015
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11. Removal of immunoglobulin-like domains from titin's spring segment alters titin splicing in mouse skeletal muscle and causes myopathy.
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Buck, Danielle, Smith III, John E., Chung, Charles S., Ono, Yasuko, Sorimachi, Hiroyuki, Labeit, Siegfried, and Granzier, Henk L.
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IMMUNOGLOBULINS , *ANIMAL genetic engineering , *TRANSGENIC mice , *LABORATORY mice , *MUSCLE diseases , *MYOSIN genetics , *GENETICS - Abstract
Titin is a molecular spring that determines the passive stiffness of muscle cells. Changes in tidn's stiffness occur in various myopathies, but whether these are a cause or an effect of the disease is unknown. We studied a novel mouse model in which titin's stiffness was slightly increased by deleting nine immunoglobulin (Ig)-like domains from ti-tin's constitutively expressed proximal tandem Ig segment (IG KO). KO mice displayed mild kyphosis, a phenotype commonly associated with skeletal muscle myopathy. Slow muscles were atrophic with alterations in myosin iso-form expression; functional studies in soleus muscle revealed a reduced specific twitch force. Exon expression analysis showed that KO mice underwent additional changes in titin splicing to yield smaller than expected titin isoforms that were much stiffer than expected. Additionally, splicing occurred in the PEVK region of titin, a find-ing confirmed at the protein level. The titin-binding protein Ankrdl was highly increased in the IG KO, but this did not play a role in generating small titin isoforms because titin expression was unaltered in IG KO mice crossed with Ankrdl-deficient mice. In contrast, the splicing factor RBM20 (RNA-binding motif 20) was also significantly in-creased in IGKOmice, and additional differential splicing was reversed in IG KOmice crossed with a mouse with reduced RBM20 activity. Thus, increasing titin's stiffness triggers pathological changes in skeletal muscle, with an important role played by RBM20. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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12. Phosphodiesterase 9a Inhibition in Mouse Models of Diastolic Dysfunction.
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Methawasin, Mei, Strom, Joshua, Borkowski, Tomasz, Hourani, Zaynab, Runyan, Ray, Smith III, John E., and Granzier, Henk
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Supplemental Digital Content is available in the text. Background: Low myocardial cGMP-PKG (cyclic guanosine monophosphate-protein kinase G) activity has been associated with increased cardiomyocyte diastolic stiffness in heart failure with preserved ejection fraction. Cyclic guanosine monophosphate is mainly hydrolyzed by PDE (phosphodiesterases) 5a and 9a. Importantly, PDE9a expression has been reported to be upregulated in human heart failure with preserved ejection fraction myocardium and chronic administration of a PDE9a inhibitor reverses preestablished cardiac hypertrophy and systolic dysfunction in mice subjected to transverse aortic constriction (TAC). We hypothesized that inhibiting PDE9a activity ameliorates diastolic dysfunction. Methods: To examine the effect of chronic PDE9a inhibition, 2 diastolic dysfunction mouse models were studied: (1) TAC-deoxycorticosterone acetate and (2) Lepr
db/db . PDE9a inhibitor (5 and 8 mg/kg per day) was administered to the mice via subcutaneously implanted osmotic minipumps for 28 days. The effect of acute PDE9a inhibition was investigated in intact cardiomyocytes isolated from TAC-deoxycorticosterone acetate mice. Atrial natriuretic peptide together with PDE9a inhibitor were administered to the isolated intact cardiomyocytes through the cell perfusate. Results: For acute inhibition, no cellular stiffness reduction was found, whereas chronic PDE9a inhibition resulted in reduced left ventricular chamber stiffness in TAC-deoxycorticosterone acetate, but not in Leprdb/db mice. Passive cardiomyocyte stiffness was reduced by chronic PDE9a inhibition, with no differences in myocardial fibrosis or cardiac morphometry. PDE9a inhibition increased the ventricular-arterial coupling ratio, reflecting impaired systolic function. Conclusions: Chronic PDE9a inhibition lowers left ventricular chamber stiffness in TAC-deoxycorticosterone acetate mice. However, the usefulness of PDE9a inhibition to treat high-diastolic stiffness may be limited as the required PDE9a inhibitor dose also impairs systolic function, observed as a decline in ventricular-arterial coordination, in this model. [ABSTRACT FROM AUTHOR]- Published
- 2020
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13. Shortening the thick filament by partial deletion of titin's C-zone alters cardiac function by reducing the operating sarcomere length range.
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Methawasin, Mei, Farman, Gerrie P., Granzier-Nakajima, Shawtaroh, Strom, Joshua, Kiss, Balazs, Smith III, John E., and Granzier, Henk
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CONNECTIN , *FIBERS - Abstract
Titin's C-zone is an inextensible segment in titin, comprised of 11 super-repeats and located in the cMyBP-C-containing region of the thick filament. Previously we showed that deletion of titin's super-repeats C1 and C2 (Ttn ΔC1–2 model) results in shorter thick filaments and contractile dysfunction of the left ventricular (LV) chamber but that unexpectedly LV diastolic stiffness is normal. Here we studied the contraction-relaxation kinetics from the time-varying elastance of the LV and intact cardiomyocyte, cellular work loops of intact cardiomyocytes, Ca2+ transients, cross-bridge kinetics, and myofilament Ca2+ sensitivity. Intact cardiomyocytes of Ttn ΔC1–2 mice exhibit systolic dysfunction and impaired relaxation. The time-varying elastance at both LV and single-cell levels showed that activation kinetics are normal in Ttn ΔC1–2 mice, but that relaxation is slower. The slowed relaxation is, in part, attributable to an increased myofilament Ca2+ sensitivity and slower early Ca2+ reuptake. Cross-bridge dynamics showed that cross-bridge kinetics are normal but that the number of force-generating cross-bridges is reduced. In vivo sarcomere length (SL) measurements revealed that in Ttn ΔC1–2 mice the operating SL range of the LV is shifted towards shorter lengths. This normalizes the apparent cell and LV diastolic stiffness but further reduces systolic force as systole occurs further down on the ascending limb of the force-SL relation. We propose that the reduced working SLs reflect titin's role in regulating diastolic stiffness by altering the number of sarcomeres in series. Overall, our study reveals that thick filament length regulation by titin's C-zone is critical for normal cardiac function. [Display omitted] • Deletion of titin's super-repeats C1 and C2 (Ttn ΔC1-2 mice ) results in shorter thick filaments and contractile dysfunction. • This contractile dysfunction is more pronounced than expected based on the reduced thick filament length per se. • Diastolic stress is expected to be increased in Ttn ΔC1-2 mice, but instead is unaltered. • These findings can be explained by the discovered shift in the operating sarcomere-length (SL) range of Ttn ΔC1-2 mice. • The shift in operating SL range towards the shorter lengths further depresses contractility but normalizes titin-based passive stress. • It appears that titin regulates passive stress at the detriment of contractile function. [ABSTRACT FROM AUTHOR]
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- 2022
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14. Nebulin and Lmod2 are critical for specifying thin-filament length in skeletal muscle.
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Kiss, Balázs, Gohlke, Jochen, Tonino, Paola, Hourani, Zaynab, Kolb, Justin, Strom, Joshua, Alekhina, Olga, Smith III, John E., Ottenheijm, Coen, Gregorio, Carol, and Granzier, Henk
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SKELETAL muscle , *NEMALINE myopathy , *SOLEUS muscle , *POSTURAL muscles , *MICROFILAMENT proteins , *GREEN fluorescent protein , *STRIATED muscle , *SKELETAL muscle physiology - Abstract
The article proposes that how strict length control by nebulin promotes high-speed shortening and that dual-regulation by nebulin/Lmod2 enhances contraction efficiency. It mentions that importance of regulating the thin-filament length in muscle controlling the number of myosin motors that generate power.
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- 2020
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15. Fine mapping titin's C-zone: Matching cardiac myosin-binding protein C stripes with titin's super-repeats.
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Tonino, Paola, Kiss, Balazs, Gohlke, Jochen, Smith III, John E., and Granzier, Henk
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PROTEIN C , *MYOSIN , *CONNECTIN , *MICROSCOPY , *STRIPES , *BINDING sites - Abstract
Titin is largely comprised of serially-linked immunoglobulin (Ig) and fibronectin type-III (Fn3) domains. Many of these domains are arranged in an 11 domain super-repeat pattern that is repeated 11 times, forming the so-named titin C-zone in the A-band region of the sarcomere. Each super-repeat is thought to provide binding sites for thick filament proteins, such as cMyBP-C (cardiac myosin-binding protein C). However, it remains to be established which of titin's 11 C-zone super-repeats anchor cMyBP-C as titin contains 11 super-repeats and cMyBP-C is found in 9 stripes only. To study the layout of titin's C-zone in relation to MyBP-C, immunolabeling studies were performed on mouse skinned myocardium with antibodies to titin and cMyBP-C, using both immuno-electron microscopy and super-resolution optical microscopy. Results indicate that cMyBP-C locates near the interface between titin's C-zone super-repeats. Studies on a mouse model in which two of titin's C-zone repeats have been genetically deleted support that the first Ig domain of a super-repeat is important for anchoring cMyBP-C but also Fn3 domains located at the end of the preceding repeat. Furthermore, not all super-repeat interfaces are equal as the interface between super-repeat 1 and 2 (close to titin's D-zone) does not contain cMyBP-C. Finally, titin's C-zone does not extend all the way to the bare zone but instead terminates at the level of the second myosin crown. This study enhances insights in the molecular layout of the C-zone of titin, its relation to cMyBP-C, and its possible roles in cardiomyopathies. Unlabelled Image • The layout of titin's C-zone in relation to MyBP-C is relevant to cardiomyopathies but is unknown. • Immuno-localization studies showed that cMyBP-C locates near the interface between titin super-repeats. • Interface titin domains that belong to two super-repeats are likely involved in anchoring cMyBP-C. • Not all super-repeat interfaces are equal: the interface between super-repeat 1 and 2 does not localize cMyBP-C. • This study enhances insights in the molecular layout of titin's C-zone and its relation to cMyBP-C. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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16. Single-Molecule Force Spectroscopy on the N2A Element of Titin: Effects of Phosphorylation and CARP
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Henk Granzier, Tiankun Zhou, Vic Keschrumrus, John E. Smith, Orfeo Sbaizero, Olga Mayans, Thomas Lanzicher, Chandra Saripalli, Lanzicher, Thoma, Zhou, Tiankun, Saripalli, Chandra, Keschrumrus, Vic, Smith III, John E., Mayans, Olga, Sbaizero, Orfeo, and Granzier, Henk
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0301 basic medicine ,mechano-signaling ,Physiology ,animal diseases ,passive stiffness ,Immunoglobulin domain ,Sarcomere ,lcsh:Physiology ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,ddc:570 ,titin ,Carp ,Original Research ,spring elements ,biology ,Strain (chemistry) ,lcsh:QP1-981 ,Chemistry ,Force spectroscopy ,Molecular spring ,post-translational modification ,biology.organism_classification ,030104 developmental biology ,biology.protein ,Biophysics ,Phosphorylation ,Titin ,passive stiffne ,spring element ,030217 neurology & neurosurgery - Abstract
Titin is a large filamentous protein that forms a sarcomeric myofilament with a molecular spring region that develops force in stretched sarcomeres. The molecular spring has a complex make-up that includes the N2A element. This element largely consists of a 104-residue unique sequence (N2A-Us) flanked by immunoglobulin domains (I80 and I81). The N2A element is of interest because it assembles a signalosome with CARP (Cardiac Ankyrin Repeat Protein) as an important component; CARP both interacts with the N2A-Us and I81 and is highly upregulated in response to mechanical stress. The mechanical properties of the N2A element were studied using single-molecule force spectroscopy, including how these properties are affected by CARP and phosphorylation. Three protein constructs were made that consisted of 0, 1, or 2 N2A-Us elements with flanking I80 and I81 domains and with specific handles at their ends for study by atomic force microscopy (AFM). The N2A-Us behaved as an entropic spring with a persistence length (Lp) of ∼0.35 nm and contour length (Lc) of ∼39 nm. CARP increased the Lp of the N2A-Us and the unfolding force of the Ig domains; force clamp experiments showed that CARP reduced the Ig domain unfolding kinetics. These findings suggest that CARP might function as a molecular chaperone that protects I81 from unfolding when mechanical stress is high. The N2A-Us was found to be a PKA substrate, and phosphorylation was blocked by CARP. Mass spectrometry revealed a PKA phosphosite (Ser-9895 in NP_001254479.2) located at the border between the N2A-Us and I81. AFM studies showed that phosphorylation affected neither the Lp of the N2A-Us nor the Ig domain unfolding force (Funfold). Simulating the force-sarcomere length relation of a single titin molecule containing all spring elements showed that the compliance of the N2A-Us only slightly reduces passive force (1.4%) with an additional small reduction by CARP (0.3%). Thus, it is improbable that the compliance of the N2A element has a mechanical function per se. Instead, it is likely that this compliance has local effects on binding of signaling molecules and that it contributes thereby to strain- and phosphorylation- dependent mechano-signaling. published
- Published
- 2020
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