Neuronal growth and synaptic function are dependent on precise protein production and turnover at the synapse. AMPK-activated protein kinase (AMPK) represents a metabolic node involved in energy sensing and in regulating synaptic protein homeostasis. However, there is ambiguity surrounding the role of AMPK in regulating neuronal growth and health. This study examined the effect of chronic AMPK activation on markers of synaptic function and growth. Retinoic-acid-differentiated SH-SY5Y human neuroblastoma cells were treated with A-769662 (100 nM) or Compound C (30 nM) for 1, 3, or 5 days before AMPK, mTORC1, and markers for synapse function were examined. Cell morphology, neuronal marker content, and location were quantified after 5 days of treatment. AMPK phosphorylation was maintained throughout all 5 days of treatment with A-769662 and resulted in chronic mTORC1 inhibition. Lower total, soma, and neuritic neuronal marker contents were observed following 5 d of AMPK activation. Neurite protein abundance and distribution was lower following 5 days of A-769662 treatment. Our data suggest that chronic AMPK activation impacts synaptic protein content and reduces neurite protein abundance and distribution. These results highlight a distinct role that metabolism plays on markers of synapse health and function.

While the exercise-induced responses of circulated biomarkers related to inflammation and brain health are well documented in humans, little is known about the effect of menopausal status on these responses. This study compared the responses of inflammatory cytokines and brain-derived neurotrophic factor (BDNF) to high-intensity exercise between pre- and postmenopausal middle-aged females. Eight premenopausal (44 ± 3 years) and seven postmenopausal (57 ± 2 years) females performed a high-intensity interval training (HIIT) session consisting of 10 × 1 min running intervals (90% maximum heart rate) separated by 1 min passive recovery intervals. Blood samples were collected at baseline (fasted), pre-exercise (postprandial), and at 0, 30, and 90 min post-HIIT and analyzed for interleukin (IL-6) and 10 (IL-10), tumour necrosis factor-alpha (TNF-α), and BDNF. IL-6 significantly increased from pre-exercise to 0 min post-HIIT in postmenopausal (+40%, p = 0.01) and to 30 min post-HIIT in premenopausal females (+60%, p = 0.02). IL-6 remained elevated at 90 min post-HIIT in premenopausal (+104%, p = 0.05) and to a higher degree in postmenopausal females (+385%, p < 0.001). IL-10 showed no response. TNF-α increased from pre- to 0 min post-HIIT (+10%, p = 0.05), then decreased to below pre-exercise at 30 min (−10%, p = 0.02) and 90 min (−5%, p = 0.04) in both groups. BDNF increased immediately post-HIIT in premenopausal (+60%, p < 0.001) but not postmenopausal females. The differences in IL-6 and BDNF responses to HIIT between pre- and postmenopausal females provide evidence of the role of female reproductive hormones in the regulation of these exercise-induced responses.

The sarco(endo)plasmic reticulum Ca²⁺ ATPase (SERCA) actively transports Ca²⁺ into the sarcoplasmic reticulum to facilitate cardiac muscle relaxation. Phospholamban (PLN) allosterically inhibits SERCA, and an imbalance of SERCA2a, dominant cardiac isoform, and PLN content disrupts Ca²⁺ homeostasis and cardiac contractility. A previous study has shown that ovariectomized (OVX) rats have reduced SERCA activity due to lowered SERCA2a and increased PLN content. Furthermore, it was found that forced treadmill running in OVX rats restored SERCA activity and protein content levels. Here, we investigated whether voluntary wheel running (VWR) would produce similar effects on cardiac SERCA function in OVX mice. Female mice were divided into the following groups for 8 weeks: SHAM; OVX; SHAM + VWR; and OVX + VWR (n = 10/group). SERCA activity and Ca²⁺ uptake assays were performed in cardiac muscle homogenates. Protein levels of SERCA2, PLN, and pPLN were determined via Western blot analysis. We found statistical interactions for Ca²⁺ uptake, maximal SERCA activity, and SERCA2a content where VWR increased these parameters in SHAM mice but not in OVX mice. We detected a main effect of OVX on PLN content, and main effects of OVX and VWR on pPLN content. The OVX mice ran significantly less than the SHAM mice, suggesting that estrogen deprivation and lack of regular exercise may blunt the effects of voluntary aerobic exercise on cardiac SERCA function.

Maternal exercise is beneficial for offspring brain development. Amyloid precursor protein (APP) influences neurogenesis and synaptic plasticity. Cleavage products of APP are implicated in the proliferation of neural progenitor cells and neuronal network development. Our study aimed to investigate differences in APP processing in active or sedentary offspring of dams who were exposed to voluntary wheel running with and without a western diet throughout gestation. Female Wistar rats (7–8 weeks old) were fed a normal chow or western diet and randomized into voluntary wheel run or sedentary conditions. Dams returned to sedentary conditions post-parturition. The pups were weaned at 6 weeks after which point half of the samples were collected, while the rest of the pups remained on a normal diet, separated into sedentary or voluntary wheel run groups, and collected 12 weeks later. In utero exposure to maternal exercise was associated with higher neuronal nuclear protein, higher soluble APPα and lower soluble APPβ in offspring prefrontal cortex tissue at 6, but not 18 weeks of age. Neuronal nuclear protein is exclusive to mature neurons implying that offspring of mothers who exercised could have more neuron maturation potentially influenced by the higher APPα content at this early developmental stage. The voluntary wheel run offspring groups had a higher mature/pro brain derived neurotrophic factor ratio compared to the sedentary counterparts. The maternal effects were isolated to the juvenile 6-week-old pups, while the differences in the adult offspring were caused by their own exercise status.

The responses of inflammatory cytokines and brain-derived neurotrophic factor (BDNF) to a high-intensity interval training (HIIT) session were compared between 7 postmenopausal (57±2 y) and 8 premenopausal females (44±3 y) during the luteal phase of their menstrual cycle, when estrogen and progesterone are highest, and. HIIT consisted of 10 x 1 min running intervals (90% maximum heart rate) separated by 1 min recovery intervals. Blood samples were collected at baseline (fasted), pre-exercise (postprandial), and 0, 30 and 90 min post-HIIT and analyzed for interleukin (IL-6) and 10 (IL-10), tumour necrosis factor-alpha (TNF-α) and BDNF. IL-6 significantly increased from pre-exercise to 0 min post-HIIT in postmenopausal (+40%, p=0.01) but 30 min post-HIIT in premenopausal females (+60%, p=0.02). IL-6 remained elevated at 90 min post-HIIT in premenopausal (+104%, p=0.05) and to a higher degree in postmenopausal (+385%, p<0.001). IL-10 showed no response. TNF-α increased from pre- to 0 min post-HIIT (+10%, p=0.05), then decreased to below pre-exercise at 30 min (-10%, p=0.02) and 90 min (-5%, p=0.04) in both groups. BDNF increased immediate post-HIIT in premenopausal (+60%, p<0.001) but not postmenopausal females. The differences in IL-6 and BDNF response to HIIT between pre and postmenopausal females provide evidence of the role of female reproductive hormones in the regulation of these exercise-induced responses.