PL - 039 Heat Shock Proteins in human single skeletal muscle fibres resist age associated alterations and differentially respond to high-intensity exercise training (original) (raw)
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Biology
Skeletal muscle is a plastic and complex tissue, rich in proteins that are subject to continuous rearrangements. Skeletal muscle homeostasis can be affected by different types of stresses, including physical activity, a physiological stressor able to stimulate a robust increase in different heat shock proteins (HSPs). The modulation of these proteins appears to be fundamental in facilitating the cellular remodeling processes related to the phenomenon of training adaptations such as hypertrophy, increased oxidative capacity, and mitochondrial activity. Among the HSPs, a special attention needs to be devoted to Hsp60 and αB-crystallin (CRYAB), proteins constitutively expressed in the skeletal muscle, where their specific features could be highly relevant in understanding the impact of different volumes of training regimes on myofiber types and in explaining the complex picture of exercise-induced mechanical strain and damaging conditions on fiber population. This knowledge could lead ...
Skeletal muscle HSP60 expression is fiber-type specific and increases after endurance training
Aims: To assess peripheral neuropathy (PN) using graded Semmes Weinstein monofilaments (SWMs) and determine factors associated with PN among adult volunteers with and without diabetes. Methods: Adult volunteers were assessed for distal sensory PN using three graded SWMs. Four PN levels were defined: 0 (no PN; felt all three filaments), 1 (subclinical PN; insensate to 1-gram filament), 2 (insensate to 10-gram), or 3 (insensate to 75-gram). Levels 2-3 were considered clinical PN. Associations with PN were determined using ordinal logistic regression. Results: In 1,564 subjects (median age 41.9 years, 50.1% women), PN was subclinical or worse in 68.9% and clinical in 11.2%. Age-sex-race-adjusted prevalence of clinical PN was greater in people with diabetes (15.3%) than without (6.1%; P <0.001). Associated factors included older age, male sex, greater BMI, greater heart rate, lower mean arterial pressure, and family history of diabetes or cardiovascular diseases. Higher PN levels associated with worse albuminuria and retinopathy. Only older age and male sex associated with PN both in people with and without diabetes. Conclusions: PN is common in our sample, notably in those without diabetes, although diabetes greatly increases its risk. Using graded SWMs may have prognostic value as it permits identification of subclinical PN.
Journal of applied physiology (Bethesda, Md. : 1985), 2002
An original method to induce heat stress was used to clarify the time course of changes in heat shock proteins (HSPs) in rat skeletal muscles during recovery after a single bout of heat stress. One hindlimb was inserted into a stainless steel can and directly heated by raising the air temperature inside the can via a flexible heater twisted around the steel can. Muscle temperature was increased gradually and maintained at 42 degrees C for 60 min. Core rectal and contralateral muscle temperatures were increased <1.5 degrees C during the heat stress. HSP60, HSP72, and heat shock cognate (HSC) 73 content in the slow soleus and fast plantaris in both limbs were determined immediately (0 h) and 2, 4, 8, 12, 24, 36, 48, or 60 h after heat stress. Within 0-4 h, all HSPs were approximately 1.5- to 2.2-fold higher in heat-stressed than contralateral soleus. Compared with the contralateral plantaris, the heat-stressed plantaris had a higher (1.5-fold) HSP60 content immediately and 2 h afte...
Journal of Applied Physiology, 2013
Frankenberg NT, Lamb GD, Vissing K, Murphy RM. Subcellular fractionation reveals HSP72 does not associate with SERCA in human skeletal muscle following damaging eccentric and concentric exercise. Through its upregulation and/or translocation, heat shock protein 72 (HSP72) is involved in protection and repair of key proteins after physiological stress. In human skeletal muscle we investigated HSP72 protein after eccentric (ECC1) and concentric (CONC) exercise and repeated eccentric exercise (ECC2; 8 wk later) and whether it translocated from its normal cytosolic location to membranes/myofibrils. HSP72 protein increased ϳ2-fold 24 h after ECC1, with no apparent change after CONC or ECC2. In resting (nonstressed) human skeletal muscle the total pool of HSP72 protein was present almost exclusively in the cytosolic fraction, and after each exercise protocol the distribution of HSP72 protein remained unaltered. Overall, the amount of HSP72 protein in the cytosol increased 24 h after ECC1, matching the fold increase that was measured in total HSP72 protein. To better ascertain the capabilities and limitations of HSP72, using quantitative Western blotting we determined the HSP72 protein content to be 11.4 mol/kg wet weight in resting human vastus lateralis muscle, which is comprised of Type I (slow-twitch) and Type II (fast-twitch) fibers. HSP72 protein content was similar in individual Type I or II fiber segments. After physiological stress, HSP72 content can increase and, although the functional consequences of increased amounts of HSP72 protein are poorly understood, it has been shown to bind to and protect protein pumps like SERCA and Na ϩ -K ϩ -ATPase. Given no translocation of cytosolic HSP72, these findings suggest eccentric contractions, unlike other forms of stress such as heat, do not trigger tight binding of HSP72 to its primary membrane-bound target proteins, in particular SERCA. HSP72; eccentric exercise; absolute quantification; single fibers; repeated bout
Journal of Applied Physiology, 2005
Heat shock protein 72 (Hsp70) is constitutively expressed in rat hindlimb muscles, reportedly in proportion to their content of type I myosin heavy chain. This distribution pattern has been suggested to result from the higher recruitment and activity of such muscles and/or a specific relationship between myosin phenotype and Hsp70 content. To differentiate between these possibilities, the fiber-specific distribution of Hsp70 was examined in male Sprague-Dawley rat plantaris under control conditions, following a fast-to-slow phenotypic shift in response to surgically induced overload (O) and in response to O when the phenotypic shift was prevented by 3,5,3′-triiodo-dl-thyronine administration. Constitutive expression of Hsp70 was restricted to type I and IIa fibers in plantaris from control rats, and this fiber-specific pattern of expression was maintained following O of up to 28 days, although Hsp70 content in the O muscle doubled. When O (for 40 days) of the plantaris was combined ...
Cells
Hsp60 is a molecular chaperone classically described as a mitochondrial protein with multiple roles in health and disease, participating to the maintenance of protein homeostasis. It is well known that skeletal muscle is a complex tissue, rich in proteins, that is, subjected to continuous rearrangements, and this homeostasis is affected by many different types of stimuli and stresses. The regular exercise induces specific histological and biochemical adaptations in skeletal muscle fibers, such as hypertrophy and an increase of mitochondria activity and oxidative capacity. The current literature is lacking in information regarding Hsp60 involvement in skeletal muscle fiber biogenesis and regeneration during exercise, and in disease conditions. Here, we briefly discuss the functions of Hsp60 in skeletal muscle fibers during exercise, inflammation, and ageing. Moreover, the potential usage of Hsp60 as a marker for disease and the evaluation of novel treatment options is also discussed....
Journal of Applied Physiology, 2009
The aims of this study were to investigate the sarcomeric accumulation and expression of heat shock proteins (HSPs) after two bouts of maximal eccentric exercise. Twenty-four subjects performed two bouts of 70 maximal voluntary eccentric actions using the elbow flexors in one arm. The bouts were separated by 3 wk. The changes in concentric (60°/s) and isometric (90°) force-generating capacity were monitored for 9 days after each bout, and biopsies were taken 1 and 48 h and 4 and 7 days after bout 1 and 1 and 48 h after bout 2. The content of HSP27, αB-crystallin, HSP70, and desmin in the cytosolic and cytoskeleton/myofibrillar fractions of homogenized muscle samples was determined by immunoassays, and the cellular and subcellular localization of the HSPs in the myofibrillar structure was analyzed by conventional and confocal immunofluorescence microscopy and quantitative electron microscopy. The force-generating capacity was reduced by ∼50% and did not recover completely during the ...
The Journal of Physical Fitness and Sports Medicine, 2015
Heat shock protein 25 (Hsp25) phosphorylation plays a protective role following mechanical stress in skeletal muscle fibers. We previously reported that phosphorylation at serine 15 of Hsp25 (p-Ser15) was enhanced during regrowth of muscle fibers in rats with muscle atrophy due to tail suspension. However, it is still unclear how p-Ser15 contributes to myogenesis and regeneration of skeletal muscle fibers. We performed the present study to investigate p-Ser15 levels at different stages of myogenic differentiation in regenerating soleus muscle fibers of adult rats. Muscle regeneration was induced by muscle injury with intramuscular injection of cardiotoxin into the soleus. On day 14 after injury, p-Ser15-positive cells were noted in the regenerating soleus. The nuclei in small p-Ser15-positive cells contained myogenin, but not Pax7. Most of these cells did not exhibit peripheral localization of dystrophin, indicating that these cells were myotubes or immature fibers. Desmin and actinin were present in all cells and fibers regardless of p-Ser15 expression. Forced contraction by nerve stimulation led to increased phosphorylation at Ser15 in the regenerating soleus, as determined by western blot. Furthermore, elevated p-Ser15 was noted particularly in small cells with cross sectional areas less than 300 µm 2. These results suggest that small immature fibers are responsive to muscle contraction, and subsequently induce a protective response through the phosphorylation of Hsp25.