Aging is associated with a progressive loss in skeletal muscle mass and strength, known as sarcopenia. Sarcopenia results in a decrease in mobility and an increased risk of developing chronic metabolic disease, thus it represents a major socio-economical problem. Age-related muscle loss cannot be consistently prevented by physical therapy and a pharmacologic therapy does not exist, probably because the molecular basis of this condition is still largely unknown. Many factors such as mitochondrial dysfunction, oxidative stress, inflammation, changes in the innervation of muscle fibers probably play an important role in age-related muscle decline. PIN1 is a widely expressed Peptydyl Prolyl cis/trans isomerase, involved in post-phosphorylation control of the function of multiple target proteins. Many evidences indicate that PIN1 controls signaling pathways involved in skeletal muscle wasting. Our results indicate that skeletal muscle of Pin1 KO mice is protected against muscle loss and weakness during aging. At the molecular level, we found 1) an increased expression of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), a transcription factor that promotes mitochondrial biogenesis, in skeletal muscle of Pin1 KO mice. Coherently with their resistance to muscle loss, we also found 2) an increase in the expression of the protein synthetic signaling proteins p70 ribosomal S6 kinase (S6K) and of its phosphorylated form in aged skeletal muscle of Pin1 KO mice compared to the wild type controls, suggesting that in these mice protein synthesis is maintained efficient. We also found 3) a significant decrease of Myostatin levels in skeletal muscle of aged Pin1 KO mice. It is well known that Myostatin is upregulated sarcopenia, it activates SMAD2/3 signaling and contributes to protein degradation and muscle atrophy. The transcriptional effects of Pin1 depletion on PGC1α and S6K genes must be mediated by a transcription factor. A putative candidate to mediate these effects is represented by the transcription factor Myocyte Enhancer Factor 2C (MEF2C), a known PIN1 target. In skeletal muscle cells a specific splice variant of MEF2C, MEF2C α1, activates the increase of skeletal muscle mass by activating the expression of IGF1 and S6K. These activities are repressed by its phosphorylation, that renders it a target for the inhibitory effect of PIN1 on its protein stability and activity. Coherently with these premises, we found 4) a decrease of MEF2C protein phosphorylation levels in aged KO mice compared to the control animals. This might at least partially contribute to the increased expression of PGC1α and of S6K. Our results indicate that PIN1 could represent a valuable pharmacological target to counteract age-related muscle loss, simultaneously modulating multiple targets in a concerted way.

PIN1: a putative molecular target to protect skeletal muscle against age-related muscle loss / Brocca, Lorenza; Grosso, Martina; Pezzini, Camilla; Semeghini, Valentina; Baruffaldi, Fiorenza; Dolfini, Diletta; Mucci, Adele; Righi, Valeria; Lorenzo Puri, Pier; Battini, Renata; Bottinelli, Roberto; Antonietta Pellegrino, Maria; Molinari, Susanna. - (2019). (Intervento presentato al convegno 16th IIM Meeting Pathogenesis and therapies of neuromuscular diseases tenutosi a Assisi nel 17-20 ottobre 2019).

PIN1: a putative molecular target to protect skeletal muscle against age-related muscle loss

Martina Grosso
Methodology
;
Valentina Semeghini
Methodology
;
Fiorenza Baruffaldi
Methodology
;
Adele Mucci
Data Curation
;
Renata Battini
Formal Analysis
;
Susanna Molinari
Conceptualization
2019

Abstract

Aging is associated with a progressive loss in skeletal muscle mass and strength, known as sarcopenia. Sarcopenia results in a decrease in mobility and an increased risk of developing chronic metabolic disease, thus it represents a major socio-economical problem. Age-related muscle loss cannot be consistently prevented by physical therapy and a pharmacologic therapy does not exist, probably because the molecular basis of this condition is still largely unknown. Many factors such as mitochondrial dysfunction, oxidative stress, inflammation, changes in the innervation of muscle fibers probably play an important role in age-related muscle decline. PIN1 is a widely expressed Peptydyl Prolyl cis/trans isomerase, involved in post-phosphorylation control of the function of multiple target proteins. Many evidences indicate that PIN1 controls signaling pathways involved in skeletal muscle wasting. Our results indicate that skeletal muscle of Pin1 KO mice is protected against muscle loss and weakness during aging. At the molecular level, we found 1) an increased expression of Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), a transcription factor that promotes mitochondrial biogenesis, in skeletal muscle of Pin1 KO mice. Coherently with their resistance to muscle loss, we also found 2) an increase in the expression of the protein synthetic signaling proteins p70 ribosomal S6 kinase (S6K) and of its phosphorylated form in aged skeletal muscle of Pin1 KO mice compared to the wild type controls, suggesting that in these mice protein synthesis is maintained efficient. We also found 3) a significant decrease of Myostatin levels in skeletal muscle of aged Pin1 KO mice. It is well known that Myostatin is upregulated sarcopenia, it activates SMAD2/3 signaling and contributes to protein degradation and muscle atrophy. The transcriptional effects of Pin1 depletion on PGC1α and S6K genes must be mediated by a transcription factor. A putative candidate to mediate these effects is represented by the transcription factor Myocyte Enhancer Factor 2C (MEF2C), a known PIN1 target. In skeletal muscle cells a specific splice variant of MEF2C, MEF2C α1, activates the increase of skeletal muscle mass by activating the expression of IGF1 and S6K. These activities are repressed by its phosphorylation, that renders it a target for the inhibitory effect of PIN1 on its protein stability and activity. Coherently with these premises, we found 4) a decrease of MEF2C protein phosphorylation levels in aged KO mice compared to the control animals. This might at least partially contribute to the increased expression of PGC1α and of S6K. Our results indicate that PIN1 could represent a valuable pharmacological target to counteract age-related muscle loss, simultaneously modulating multiple targets in a concerted way.
2019
ott-2019
16th IIM Meeting Pathogenesis and therapies of neuromuscular diseases
Assisi
17-20 ottobre 2019
Brocca, Lorenza; Grosso, Martina; Pezzini, Camilla; Semeghini, Valentina; Baruffaldi, Fiorenza; Dolfini, Diletta; Mucci, Adele; Righi, Valeria; Lorenz...espandi
PIN1: a putative molecular target to protect skeletal muscle against age-related muscle loss / Brocca, Lorenza; Grosso, Martina; Pezzini, Camilla; Semeghini, Valentina; Baruffaldi, Fiorenza; Dolfini, Diletta; Mucci, Adele; Righi, Valeria; Lorenzo Puri, Pier; Battini, Renata; Bottinelli, Roberto; Antonietta Pellegrino, Maria; Molinari, Susanna. - (2019). (Intervento presentato al convegno 16th IIM Meeting Pathogenesis and therapies of neuromuscular diseases tenutosi a Assisi nel 17-20 ottobre 2019).
File in questo prodotto:
File Dimensione Formato  
Program_Abstracts_IIM2019.pdf

Accesso riservato

Tipologia: Altro
Dimensione 3.75 MB
Formato Adobe PDF
3.75 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1306126
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact