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Abnormalities of AMPK activation and glucose uptake in cultured skeletal muscle cells from individuals with chronic fatigue syndrome.

Brown AE, Jones DE, Walker M, Newton JL - PLoS ONE (2015)

Bottom Line: Control cultures subjected to 16 h EPS showed a significant increase in both AMPK phosphorylation and glucose uptake compared with unstimulated cells.IL6 secretion in response to EPS was significantly reduced in CFS compared with control cultures at all time points measured.We found four main differences in cultured skeletal muscle cells from subjects with CFS; increased myogenin expression in the basal state, impaired activation of AMPK, impaired stimulation of glucose uptake and diminished release of IL6.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cellular Medicine, William Leech Building, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.

ABSTRACT

Background: Post exertional muscle fatigue is a key feature in Chronic Fatigue Syndrome (CFS). Abnormalities of skeletal muscle function have been identified in some but not all patients with CFS. To try to limit potential confounders that might contribute to this clinical heterogeneity, we developed a novel in vitro system that allows comparison of AMP kinase (AMPK) activation and metabolic responses to exercise in cultured skeletal muscle cells from CFS patients and control subjects.

Methods: Skeletal muscle cell cultures were established from 10 subjects with CFS and 7 age-matched controls, subjected to electrical pulse stimulation (EPS) for up to 24h and examined for changes associated with exercise.

Results: In the basal state, CFS cultures showed increased myogenin expression but decreased IL6 secretion during differentiation compared with control cultures. Control cultures subjected to 16 h EPS showed a significant increase in both AMPK phosphorylation and glucose uptake compared with unstimulated cells. In contrast, CFS cultures showed no increase in AMPK phosphorylation or glucose uptake after 16 h EPS. However, glucose uptake remained responsive to insulin in the CFS cells pointing to an exercise-related defect. IL6 secretion in response to EPS was significantly reduced in CFS compared with control cultures at all time points measured.

Conclusion: EPS is an effective model for eliciting muscle contraction and the metabolic changes associated with exercise in cultured skeletal muscle cells. We found four main differences in cultured skeletal muscle cells from subjects with CFS; increased myogenin expression in the basal state, impaired activation of AMPK, impaired stimulation of glucose uptake and diminished release of IL6. The retention of these differences in cultured muscle cells from CFS subjects points to a genetic/epigenetic mechanism, and provides a system to identify novel therapeutic targets.

No MeSH data available.


Related in: MedlinePlus

IL6 secretion in control and CFS cell cultures.Fresh media was added to 5 controls and 10 CFS cultures and subjected to EPS for 4 and 24h. After 24h, media was removed and assayed for IL6 secretion by ELISA. Open bar: Unstimulated, closed bar: 4h stimulation, grey bar: 24h stimulation. Results are expressed as mean±SEM. #p<0.001 vs control unstimulated, * p<0.05 vs corresponding control.
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pone.0122982.g004: IL6 secretion in control and CFS cell cultures.Fresh media was added to 5 controls and 10 CFS cultures and subjected to EPS for 4 and 24h. After 24h, media was removed and assayed for IL6 secretion by ELISA. Open bar: Unstimulated, closed bar: 4h stimulation, grey bar: 24h stimulation. Results are expressed as mean±SEM. #p<0.001 vs control unstimulated, * p<0.05 vs corresponding control.

Mentions: Skeletal muscle produces IL6 in response to contraction. The effect of EPS on IL6 secretion is shown in Fig 4. Control cells showed no change in secretion at 4h but was significantly increased at 24h (p<0.001, vs unstimulated). In the CFS group, IL6 secretion showed the same pattern of release but secretion at all time points was significantly decreased compared to control (p<0.05 vs corresponding control), reflecting the reduced basal IL6 release observed previously.


Abnormalities of AMPK activation and glucose uptake in cultured skeletal muscle cells from individuals with chronic fatigue syndrome.

Brown AE, Jones DE, Walker M, Newton JL - PLoS ONE (2015)

IL6 secretion in control and CFS cell cultures.Fresh media was added to 5 controls and 10 CFS cultures and subjected to EPS for 4 and 24h. After 24h, media was removed and assayed for IL6 secretion by ELISA. Open bar: Unstimulated, closed bar: 4h stimulation, grey bar: 24h stimulation. Results are expressed as mean±SEM. #p<0.001 vs control unstimulated, * p<0.05 vs corresponding control.
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pone.0122982.g004: IL6 secretion in control and CFS cell cultures.Fresh media was added to 5 controls and 10 CFS cultures and subjected to EPS for 4 and 24h. After 24h, media was removed and assayed for IL6 secretion by ELISA. Open bar: Unstimulated, closed bar: 4h stimulation, grey bar: 24h stimulation. Results are expressed as mean±SEM. #p<0.001 vs control unstimulated, * p<0.05 vs corresponding control.
Mentions: Skeletal muscle produces IL6 in response to contraction. The effect of EPS on IL6 secretion is shown in Fig 4. Control cells showed no change in secretion at 4h but was significantly increased at 24h (p<0.001, vs unstimulated). In the CFS group, IL6 secretion showed the same pattern of release but secretion at all time points was significantly decreased compared to control (p<0.05 vs corresponding control), reflecting the reduced basal IL6 release observed previously.

Bottom Line: Control cultures subjected to 16 h EPS showed a significant increase in both AMPK phosphorylation and glucose uptake compared with unstimulated cells.IL6 secretion in response to EPS was significantly reduced in CFS compared with control cultures at all time points measured.We found four main differences in cultured skeletal muscle cells from subjects with CFS; increased myogenin expression in the basal state, impaired activation of AMPK, impaired stimulation of glucose uptake and diminished release of IL6.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cellular Medicine, William Leech Building, Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.

ABSTRACT

Background: Post exertional muscle fatigue is a key feature in Chronic Fatigue Syndrome (CFS). Abnormalities of skeletal muscle function have been identified in some but not all patients with CFS. To try to limit potential confounders that might contribute to this clinical heterogeneity, we developed a novel in vitro system that allows comparison of AMP kinase (AMPK) activation and metabolic responses to exercise in cultured skeletal muscle cells from CFS patients and control subjects.

Methods: Skeletal muscle cell cultures were established from 10 subjects with CFS and 7 age-matched controls, subjected to electrical pulse stimulation (EPS) for up to 24h and examined for changes associated with exercise.

Results: In the basal state, CFS cultures showed increased myogenin expression but decreased IL6 secretion during differentiation compared with control cultures. Control cultures subjected to 16 h EPS showed a significant increase in both AMPK phosphorylation and glucose uptake compared with unstimulated cells. In contrast, CFS cultures showed no increase in AMPK phosphorylation or glucose uptake after 16 h EPS. However, glucose uptake remained responsive to insulin in the CFS cells pointing to an exercise-related defect. IL6 secretion in response to EPS was significantly reduced in CFS compared with control cultures at all time points measured.

Conclusion: EPS is an effective model for eliciting muscle contraction and the metabolic changes associated with exercise in cultured skeletal muscle cells. We found four main differences in cultured skeletal muscle cells from subjects with CFS; increased myogenin expression in the basal state, impaired activation of AMPK, impaired stimulation of glucose uptake and diminished release of IL6. The retention of these differences in cultured muscle cells from CFS subjects points to a genetic/epigenetic mechanism, and provides a system to identify novel therapeutic targets.

No MeSH data available.


Related in: MedlinePlus