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Reactivation of autophagy by spermidine ameliorates the myopathic defects of collagen VI- mice.

Chrisam M, Pirozzi M, Castagnaro S, Blaauw B, Polishchuck R, Cecconi F, Grumati P, Bonaldo P - Autophagy (2015)

Bottom Line: Autophagy is a self-degradative process responsible for the clearance of damaged or unnecessary cellular components.We have previously found that persistence of dysfunctional organelles due to autophagy failure is a key event in the pathogenesis of COL6/collagen VI-related myopathies, and have demonstrated that reactivation of a proper autophagic flux rescues the muscle defects of Col6a1- (col6a1(-/-)) mice.The beneficial effects of spermidine, together with its being easy to administer and the lack of overt side effects, open the field for the design of novel nutraceutical strategies for the treatment of muscle diseases characterized by autophagy impairment.

View Article: PubMed Central - PubMed

Affiliation: a Department of Molecular Medicine ; University of Padova ; Padova , Italy.

ABSTRACT
Autophagy is a self-degradative process responsible for the clearance of damaged or unnecessary cellular components. We have previously found that persistence of dysfunctional organelles due to autophagy failure is a key event in the pathogenesis of COL6/collagen VI-related myopathies, and have demonstrated that reactivation of a proper autophagic flux rescues the muscle defects of Col6a1- (col6a1(-/-)) mice. Here we show that treatment with spermidine, a naturally occurring nontoxic autophagy inducer, is beneficial for col6a1(-/-) mice. Systemic administration of spermidine in col6a1(-/-) mice reactivated autophagy in a dose-dependent manner, leading to a concurrent amelioration of the histological and ultrastructural muscle defects. The beneficial effects of spermidine, together with its being easy to administer and the lack of overt side effects, open the field for the design of novel nutraceutical strategies for the treatment of muscle diseases characterized by autophagy impairment.

No MeSH data available.


Related in: MedlinePlus

Spermidine modulates the AKT-FOXO axis in skeletal muscle. (A) Western blot analysis of AKT phosphorylation in protein extracts from tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice. Densitometric quantifications of P-AKT vs AKT, as determined by 3 independent western blot experiments, are shown on the right panel (n = 3; **, P< 0.01; ***, P < 0.001). (B–E) Real-time RT-PCR analysis of mRNA levels for Bnip3 (B), Ctsl (C) and Map1lc3b (E) in tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice (n = 3 or 4; ***, P < 0.001; ** P < 0.01; *, P < 0.05; NS, not significant). 24 h, twenty-four hour-long starvation; Spd IP, spermidine i.p.; Spd PO, spermidine per os. WT, wild-type.
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f0003: Spermidine modulates the AKT-FOXO axis in skeletal muscle. (A) Western blot analysis of AKT phosphorylation in protein extracts from tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice. Densitometric quantifications of P-AKT vs AKT, as determined by 3 independent western blot experiments, are shown on the right panel (n = 3; **, P< 0.01; ***, P < 0.001). (B–E) Real-time RT-PCR analysis of mRNA levels for Bnip3 (B), Ctsl (C) and Map1lc3b (E) in tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice (n = 3 or 4; ***, P < 0.001; ** P < 0.01; *, P < 0.05; NS, not significant). 24 h, twenty-four hour-long starvation; Spd IP, spermidine i.p.; Spd PO, spermidine per os. WT, wild-type.

Mentions: Spermidine induces autophagy through modifications at the level of the acetylproteome, thus modifying the expression levels of several genes.9,10 In previous studies aimed at mechanistic insight into the autophagic defects of COL6-related myopathies, we have demonstrated that col6a1−/− muscles display a hyperactivation of the AKT-MTOR pathway and that this signaling defect plays a key role in the autophagy impairment.8 AKT kinase negatively regulates the activity of FOXO (forkhead box O) transcription factors by phosphorylation, and decreased levels of phosphorylated AKT represent a permissive condition for FOXO activation.19,20 To understand whether the autophagy-inducing effects of spermidine involve the AKT-FOXO axis, we investigated the activation state of AKT and the mRNA levels of several FOXO target genes in tibialis anterior of wild-type and col6a1−/− mice subjected to i.p. treatment with spermidine at 50 mg/kg for 10 d. Chronic spermidine administration led to decreased AKT phosphorylation, an effect which was particularly strong in col6a1−/− mice subjected to 24 h starvation (Fig. 3A). Real time PCR for Bnip3 (BCL2/adenovirus E1B 19kDa interacting protein 3), Ctsl (cathepsin L), and Map1lc3b, 3 autophagy-related genes regulated by the AKT-FOXO axis,19 showed significantly increased levels of their transcript in spermidine-treated, 24-h-fasted col6a1−/− mice (Fig. 3B to D). These results indicate that spermidine elicits AKT dephosphorylation, which in turn triggers the translocation of FOXO transcription factors into the nucleus with the consequent increased transcription of FOXO target genes, including autophagy-related genes.Figure 3.


Reactivation of autophagy by spermidine ameliorates the myopathic defects of collagen VI- mice.

Chrisam M, Pirozzi M, Castagnaro S, Blaauw B, Polishchuck R, Cecconi F, Grumati P, Bonaldo P - Autophagy (2015)

Spermidine modulates the AKT-FOXO axis in skeletal muscle. (A) Western blot analysis of AKT phosphorylation in protein extracts from tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice. Densitometric quantifications of P-AKT vs AKT, as determined by 3 independent western blot experiments, are shown on the right panel (n = 3; **, P< 0.01; ***, P < 0.001). (B–E) Real-time RT-PCR analysis of mRNA levels for Bnip3 (B), Ctsl (C) and Map1lc3b (E) in tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice (n = 3 or 4; ***, P < 0.001; ** P < 0.01; *, P < 0.05; NS, not significant). 24 h, twenty-four hour-long starvation; Spd IP, spermidine i.p.; Spd PO, spermidine per os. WT, wild-type.
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f0003: Spermidine modulates the AKT-FOXO axis in skeletal muscle. (A) Western blot analysis of AKT phosphorylation in protein extracts from tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice. Densitometric quantifications of P-AKT vs AKT, as determined by 3 independent western blot experiments, are shown on the right panel (n = 3; **, P< 0.01; ***, P < 0.001). (B–E) Real-time RT-PCR analysis of mRNA levels for Bnip3 (B), Ctsl (C) and Map1lc3b (E) in tibialis anterior muscles of untreated (–) and i.p. spermidine-treated (+) wild-type and col6a1−/− mice (n = 3 or 4; ***, P < 0.001; ** P < 0.01; *, P < 0.05; NS, not significant). 24 h, twenty-four hour-long starvation; Spd IP, spermidine i.p.; Spd PO, spermidine per os. WT, wild-type.
Mentions: Spermidine induces autophagy through modifications at the level of the acetylproteome, thus modifying the expression levels of several genes.9,10 In previous studies aimed at mechanistic insight into the autophagic defects of COL6-related myopathies, we have demonstrated that col6a1−/− muscles display a hyperactivation of the AKT-MTOR pathway and that this signaling defect plays a key role in the autophagy impairment.8 AKT kinase negatively regulates the activity of FOXO (forkhead box O) transcription factors by phosphorylation, and decreased levels of phosphorylated AKT represent a permissive condition for FOXO activation.19,20 To understand whether the autophagy-inducing effects of spermidine involve the AKT-FOXO axis, we investigated the activation state of AKT and the mRNA levels of several FOXO target genes in tibialis anterior of wild-type and col6a1−/− mice subjected to i.p. treatment with spermidine at 50 mg/kg for 10 d. Chronic spermidine administration led to decreased AKT phosphorylation, an effect which was particularly strong in col6a1−/− mice subjected to 24 h starvation (Fig. 3A). Real time PCR for Bnip3 (BCL2/adenovirus E1B 19kDa interacting protein 3), Ctsl (cathepsin L), and Map1lc3b, 3 autophagy-related genes regulated by the AKT-FOXO axis,19 showed significantly increased levels of their transcript in spermidine-treated, 24-h-fasted col6a1−/− mice (Fig. 3B to D). These results indicate that spermidine elicits AKT dephosphorylation, which in turn triggers the translocation of FOXO transcription factors into the nucleus with the consequent increased transcription of FOXO target genes, including autophagy-related genes.Figure 3.

Bottom Line: Autophagy is a self-degradative process responsible for the clearance of damaged or unnecessary cellular components.We have previously found that persistence of dysfunctional organelles due to autophagy failure is a key event in the pathogenesis of COL6/collagen VI-related myopathies, and have demonstrated that reactivation of a proper autophagic flux rescues the muscle defects of Col6a1- (col6a1(-/-)) mice.The beneficial effects of spermidine, together with its being easy to administer and the lack of overt side effects, open the field for the design of novel nutraceutical strategies for the treatment of muscle diseases characterized by autophagy impairment.

View Article: PubMed Central - PubMed

Affiliation: a Department of Molecular Medicine ; University of Padova ; Padova , Italy.

ABSTRACT
Autophagy is a self-degradative process responsible for the clearance of damaged or unnecessary cellular components. We have previously found that persistence of dysfunctional organelles due to autophagy failure is a key event in the pathogenesis of COL6/collagen VI-related myopathies, and have demonstrated that reactivation of a proper autophagic flux rescues the muscle defects of Col6a1- (col6a1(-/-)) mice. Here we show that treatment with spermidine, a naturally occurring nontoxic autophagy inducer, is beneficial for col6a1(-/-) mice. Systemic administration of spermidine in col6a1(-/-) mice reactivated autophagy in a dose-dependent manner, leading to a concurrent amelioration of the histological and ultrastructural muscle defects. The beneficial effects of spermidine, together with its being easy to administer and the lack of overt side effects, open the field for the design of novel nutraceutical strategies for the treatment of muscle diseases characterized by autophagy impairment.

No MeSH data available.


Related in: MedlinePlus