Dietary Aronia melanocarpa extract enhances mTORC1 signaling, but has no effect on protein synthesis and protein breakdown-related signaling, in response to resistance exercise in rat skeletal muscle

Abstract

BackgroundUrsolic acid altered muscle protein metabolism in normal and resting conditions after acute resistance exercise, suggesting that eating fruits rich in ursolic acid could enhance muscle protein synthesis and decrease muscle degradation. Aronia melanocarpa, a member of the family Rosaceae and native to North America and Eastern Canada, is rich in ursolic acid. In this study, we examined the effects of A. melanocarpa extract (AME) supplementation on the mTORC1 signaling pathway and muscle degradation-related factors in rats, both alone and in combination with resistance exercise.MethodsMale Sprague-Dawley rats were divided into AME and normal chow (NOR) groups. AME group was fed chow providing a dose of 3 g/kg of AME and 115 mg/kg of ursolic acid for 7 days, whereas NOR rats were fed normal powder chow. The right gastrocnemius muscle of each animal was isometrically exercised (5 sets of ten 3-s contractions, with a 7-s interval between contractions and 3-min rest intervals between sets), while the left gastrocnemius muscle served as an internal control. Western blotting and real-time polymerase chain reaction were used to assess expression of factors involved in the mTORC1 signaling pathway and muscle degradation.ResultsAt 1 h after resistance exercise, phosphorylation of ERK1/2 was significantly increased by AME consumption. At 6 h after resistance exercise, AME consumption significantly increased the phosphorylation of Akt, p70S6K, rpS6, and AMPK. It also increased MAFbx expression. Furthermore, AME significantly increased the phosphorylation of p70S6K and rpS6 in response to resistance exercise. However, AME did not increase muscle protein synthesis (MPS) after resistance exercise. AME did not affect the expression of any of the mediators of protein degradation, with the exception of MAFbx.ConclusionsDietary AME enhanced mTORC1 activation in response to resistance exercise without increasing MPS. Moreover, it neither accelerated muscle protein degradation nor otherwise negatively affected protein metabolism. Further study is needed to clarify the effect of the combination of AME and chronic resistance training on muscle hypertrophy.

Geroprotective effects ofAronia melanocarpafruit extract onDrosophila melanogaster

“…Treatment of a glioblastoma cell line (U373) with an extract of chokeberry ( Aronia melanocarpa ) and curcumin ( Curcuma longa ), for 48 hours, caused a decrease in the expression of the MMP-2, −14, −16 and −17 genes(Abdullah Thani et al 2012). The extract of chokeberry (2.9 g/kg of body weight) supplementation with food and further exercise increased the activity of mTORC1 in rats (Makanae et al 2019). The the positive effect on lifespan has been reported to be associated with increased expression of SOD , CAT , GPx genes and suppression of the MTH gene (Jo and Imm 2017; Lashmanova et al 2019; Peng et al 2011; Peng et al 2012; Wang et al 2015).…”

“…No reuse allowed without permission. (Makanae et al 2019). The the positive effect on lifespan has been reported to be associated with increased expression of SOD, CAT, GPx genes and suppression of the MTH gene (Jo and Imm 2017;Lashmanova et al 2019;Peng et al 2011;Peng et al 2012;Wang et al 2015).…”

“…It was found that in adult mice (aged 20 – 22 months), when added to food, rapamycin exhibited the greatest geroprotective effect than in young mice (Wilkinson et al 2012). The beneficial effects of chokeberry extracts have been revealed in different in vitro and in vivo models and at different levels from the cellular (Abdullah Thani et al 2012; Cvetanović et al 2018; Parzonko et al 2015; Valdez et al 2020) before organismic (Makanae et al 2019).…”

Aronia Upregulates Myogenic Differentiation and Augments Muscle Mass and Function Through Muscle Metabolism

“…The fruit of aronia consists of a variety of ingredients, such as anthocyanin, flavonoids, ursolic acid, acetylursolic acid, and oleanolic acid (28,50,51). These components have been implicated in the increase of muscle mass, fast, and slow muscle fiber size and muscle strength (52)(53)(54).…”

“…Since Akt is the major downstream signaling component of IGF-1, this is in consistent with our current data. Although the functional aspect is not addressed, another study has proposed that the effect of aronia might be exerted through mTORC1 activation in response to resistance exercise without increasing muscle protein synthesis ( 50 ). Further studies are required to define the regulatory mechanisms by which aronia exerts the beneficial effect on muscle mass and strength.…”