αB-crystallin activation in cardiac muscle by acute exercise mirrors the sHSP kinetic in oxidative skeletal muscle fibers: animal and cellular study

2017 ◽  
Vol 108 ◽  
pp. S78
Author(s):  
Ambra Antonioni ◽  
Ivan Dimauro ◽  
Neri Mercatelli ◽  
Filippo Macaluso ◽  
Rosario Barone ◽  
...  
2019 ◽  
Vol 105 (2) ◽  
pp. 557-566 ◽  
Author(s):  
Kittichate Visuttijai ◽  
Carola Hedberg-Oldfors ◽  
Christer Thomsen ◽  
Emma Glamuzina ◽  
Cornelia Kornblum ◽  
...  

Abstract Context Glycogenin is considered to be an essential primer for glycogen biosynthesis. Nevertheless, patients with glycogenin-1 deficiency due to biallelic GYG1 (NM_004130.3) mutations can store glycogen in muscle. Glycogenin-2 has been suggested as an alternative primer for glycogen synthesis in patients with glycogenin-1 deficiency. Objective The objective of this article is to investigate the importance of glycogenin-1 and glycogenin-2 for glycogen synthesis in skeletal and cardiac muscle. Design, Setting, and Patients Glycogenin-1 and glycogenin-2 expression was analyzed by Western blot, mass spectrometry, and immunohistochemistry in liver, heart, and skeletal muscle from controls and in skeletal and cardiac muscle from patients with glycogenin-1 deficiency. Results Glycogenin-1 and glycogenin-2 both were found to be expressed in the liver, but only glycogenin-1 was identified in heart and skeletal muscle from controls. In patients with truncating GYG1 mutations, neither glycogenin-1 nor glycogenin-2 was expressed in skeletal muscle. However, nonfunctional glycogenin-1 but not glycogenin-2 was identified in cardiac muscle from patients with cardiomyopathy due to GYG1 missense mutations. By immunohistochemistry, the mutated glycogenin-1 colocalized with the storage of glycogen and polyglucosan in cardiomyocytes. Conclusions Glycogen can be synthesized in the absence of glycogenin, and glycogenin-1 deficiency is not compensated for by upregulation of functional glycogenin-2. Absence of glycogenin-1 leads to the focal accumulation of glycogen and polyglucosan in skeletal muscle fibers. Expression of mutated glycogenin-1 in the heart is deleterious, and it leads to storage of abnormal glycogen and cardiomyopathy.


1989 ◽  
Vol 37 (2) ◽  
pp. 159-164 ◽  
Author(s):  
F Thiebaut ◽  
T Tsuruo ◽  
H Hamada ◽  
M M Gottesman ◽  
I Pastan ◽  
...  

Using peroxidase immunohistochemistry, we examined the distribution of P170, a multidrug transport protein, in normal tissues by use of two different monoclonal antibodies (MAb). MAb MRK16 is a MAb that has been shown to react with an epitope in P170 located on the external face of the plasma membrane of multidrug-resistant human cells. MAb C219 has been shown to react with P170 in many mammalian species, and detects an epitope located on the cytoplasmic face of the plasma membrane. Using MRK16, we have previously described the localization of P170 on the bile canalicular face of hepatocytes, the apical surface of proximal tubular cells in kidney, and the surface epithelium in the lower GI tract in normal human tissues. In this work, we report that MRK16 also detects P170 in the capillaries of some human brain samples. A similar pattern was found using MAb C219 in rat tissues. in addition, MAb C219 showed intense localization in selected skeletal muscle fibers and all cardiac muscle fibers in rat and human tissues. ATPase cytochemistry showed that these reactive skeletal muscle fibers were of the type I (slow-twitch) class. Other additional sites of C219 reactivity in rat tissues were found in pancreatic acini, seminal vesicle, and testis. Electrophoretic gel immunoblotting showed two protein bands reactive with MAb C219. In liver, MAb C219 reacted with a approximately 170 KD band. In skeletal and cardiac muscle, MAb C219 reacted with a approximately 200 KD band which migrated in the same position as myosin. This band also reacted with an antibody to skeletal muscle myosin. This result suggests that C219 may crossreact with the heavy chain of muscle myosin in cardiac and skeletal muscle. Because MAb C219 reacts with proteins other than P170, it should be used with caution in studies of multidrug resistance.


2012 ◽  
Vol 303 (6) ◽  
pp. C654-C665 ◽  
Author(s):  
Noni T. Larkins ◽  
Robyn M. Murphy ◽  
Graham D. Lamb

Heat shock proteins (HSPs) help maintain cellular function in stressful situations, but the processes controlling their interactions with target proteins are not well defined. This study examined the binding of HSP72, HSP25, and αB-crystallin in skeletal muscle fibers following various stresses. Rat soleus (SOL) and extensor digitorum longus (EDL) muscles were subjected in vitro to heat stress or strongly fatiguing stimulation. Superficial fibers were “skinned” by microdissection and HSP diffusibility assessed from the extent of washout following 10- to 30 min exposure to a physiological intracellular solution. In fibers from nonstressed (control) SOL muscle, >80% of each HSP is readily diffusible. However, after heating a muscle to 40°C for 30 min ∼95% of HSP25 and αB-crystallin becomes tightly bound at nonmembranous myofibrillar sites, whereas HSP72 bound at membranous sites only after heat treatment to ≥44°C. The ratio of reduced to oxidized cytoplasmic glutathione (GSH:GSSG) decreased approximately two- and fourfold after heating muscles to 40° and 45°C, respectively. The reducing agent dithiothreitol reversed HSP72 binding in heated muscles but had no effect on the other HSPs. Intense in vitro stimulation of SOL muscles, sufficient to elicit substantial oxidation-related loss of maximum force and approximately fourfold decrease in the GSH:GSSG ratio, had no effect on diffusibility of any of the HSPs. When skinned fibers from heat-treated muscles were bathed with additional exogenous HSP72, total binding increased approximately two- and 10-fold, respectively, in SOL and EDL fibers, possibly reflective of the relative sarco(endo)plasmic reticulum Ca2+-ATPase pump densities in the two fiber types. Phosphorylation at Ser59 on αB-crystallin and Ser85 on HSP25 increased with heat treatment but did not appear to determine HSP binding. The findings highlight major differences in the processes controlling binding of HSP72 and the two small HSPs. Binding was not directly related to cytoplasmic oxidative status, but oxidation of cysteine residues influenced HSP72 binding.


Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).


Author(s):  
Leonardo Hernández

The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle fibers of the frog (Rana pipiens) under conditions of chronic denervation was investigated.Isometric tension was recorded from slow bundles of normal and denervated cruralis muscle in normal solution and in solutions with free calcium concentration solution or in solutions where other divalent cations (Sr2+, Ni2+, Co2+ or Mn2+) substituted for calcium. In the second week after nerve section, in Ca2+-free solutions, we observed that contractures (evoked from 40 to 80 mM-K+) of non-denervated muscles showed significantly higher tensions (p<0.05), than those from denervated bundles. Likewise, in solutions where calcium was substituted by all divalent cations tested, with exception of Mn2+, the denervated bundles displayed lower tension than non-denervated, also in the second week of denervation. In this case, the Ca2+ substitution by Sr2+ caused the higher decrease in tension, followed by Co2+ and Ni2+, which were different to non-denervated bundles, as the lowest tension was developed by Mn2+, followed by Co2+, and then Ni2+ and Sr2+. After the third week, we observed a recovery in tension. These results suggest that denervation altering the binding capacity to divalent cations of the voltage sensor.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Kazuki Yamamoto ◽  
Nao Yamaoka ◽  
Yu Imaizumi ◽  
Takunori Nagashima ◽  
Taiki Furutani ◽  
...  

A three-dimensional human neuromuscular tissue model that mimics the physically separated structures of motor neurons and skeletal muscle fibers is presented.


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