Periodic Reporting for period 1 - AmyloAge (AmyloAge: balancing proteostasis and metabolism in age-related muscular degeneration)
Reporting period: 2020-09-01 to 2022-08-31
The combination of obesity with low muscle mass, termed sarcopenic obesity, is a huge risk factor for disease and early death. Yet, we do not know much yet about the effects of diet, sex and age on sarcopenic obesity.
Project AmyloAge has three objectives (O):
O1: To identify and quantify the variations in genes and proteins related to protein aggregation in the muscle
I am preparing a publication in which I demonstrate that aggregation-prone proteins other than amyloid-β also accumulate with calory-rich diets. Moreover, increased amounts of aggregation-prone proteins are correlated with perturbed mitochondria. Chaperones in the α-crystallin/Hsp20 family correlate negatively with these aggregation-prone proteins. Moreover, humans with higher expression of α-crystallins seem to have increased muscle mass and increased basal metabolism.
O2: To uncover the impact of mitochondrial activity on muscle proteostasis
I made use of the worm RIAILS reference genetic population. Here, the project identified new genetic determinants of mitochondrial stress triggered by the mitochondrial ribosome inhibitor doxycycline. From every worm line, we assessed molecular and phenotypic traits. Short-lived strains benefit more from doxycycline, and the longer the worms took to develop and lay eggs, the longer they lived. I collaborated with other lab members to genetically map and validate new compounds that trigger beneficial mitochondrial stresses.
I next investigated whether the mitochondrial response to diet is different between male and female mice. I found that the ratios of certain important mitochondrial complexes are perturbed when mice are fed a high-fat diet. Moreover, some of these perturbations are different between male and female mice. The project furthermore revealed that exercising results in the production of an important inflammation-stimulating protein in the brain which causes the muscles to burn more fat.
O3: To uncover the genetic and metabolic pathways that drive muscle aging
Through a collaboration with a geology research group in France, I was able to assess the metal contents (“metallome”) in mice at different ages. The metallome shows consistent changes with aging. The project reveals for example that iron concentration and copper isotope composition are related to age-related muscle metabolism.
The project further suggests that muscle protein aggregation diseases are worst displays of a natural variation in protein aggregation during aging. AmyloAge identifies an important class of fatty acids, the sphingolipids, as key regulators of disease severity in Duchenne muscular dystrophy. Sphingolipids accumulate in the muscles of mouse models for Duchenne muscular dystrophy. Myriocin, a potent inhibitor of sphingolipid synthesis, strongly reduces sphingolipids, and improves the molecular signature, as well as the functional performance in our mouse model.
Project AmyloAge has three objectives (O):
O1: To identify and quantify the variations in genes and proteins related to protein aggregation in the muscle
I am preparing a publication in which I demonstrate that aggregation-prone proteins other than amyloid-β also accumulate with calory-rich diets. Moreover, increased amounts of aggregation-prone proteins are correlated with perturbed mitochondria. Chaperones in the α-crystallin/Hsp20 family correlate negatively with these aggregation-prone proteins. Moreover, humans with higher expression of α-crystallins seem to have increased muscle mass and increased basal metabolism.
O2: To uncover the impact of mitochondrial activity on muscle proteostasis
I made use of the worm RIAILS reference genetic population. Here, the project identified new genetic determinants of mitochondrial stress triggered by the mitochondrial ribosome inhibitor doxycycline. From every worm line, we assessed molecular and phenotypic traits. Short-lived strains benefit more from doxycycline, and the longer the worms took to develop and lay eggs, the longer they lived. I collaborated with other lab members to genetically map and validate new compounds that trigger beneficial mitochondrial stresses.
I next investigated whether the mitochondrial response to diet is different between male and female mice. I found that the ratios of certain important mitochondrial complexes are perturbed when mice are fed a high-fat diet. Moreover, some of these perturbations are different between male and female mice. The project furthermore revealed that exercising results in the production of an important inflammation-stimulating protein in the brain which causes the muscles to burn more fat.
O3: To uncover the genetic and metabolic pathways that drive muscle aging
Through a collaboration with a geology research group in France, I was able to assess the metal contents (“metallome”) in mice at different ages. The metallome shows consistent changes with aging. The project reveals for example that iron concentration and copper isotope composition are related to age-related muscle metabolism.
The project further suggests that muscle protein aggregation diseases are worst displays of a natural variation in protein aggregation during aging. AmyloAge identifies an important class of fatty acids, the sphingolipids, as key regulators of disease severity in Duchenne muscular dystrophy. Sphingolipids accumulate in the muscles of mouse models for Duchenne muscular dystrophy. Myriocin, a potent inhibitor of sphingolipid synthesis, strongly reduces sphingolipids, and improves the molecular signature, as well as the functional performance in our mouse model.
I investigated muscle proteostasis in 3 diverse murine genetic reference populations fed with either chow diet (CD) or a high-calory diet (high-fat diet (HFD) or Western diet (WD)). I performed high-throughput dot blot analysis of aggregation-prone proteins in the soluble and insoluble fraction of the skeletal muscles of 977 mice. I further analyzed the transcriptomes of 349 of these mice and performed proteomics in both fractions for 96 mice based on a library of 24 fractions. These multi-omics data were then compared to a set of 23 phenotypic traits. I also validated his results via two-sample Mendelian randomization in large human cohorts.
I searched the RIAILs proteomics LC-MS files with Maxquant. Proteins were quantified with MSqRob and protein level summaries for correlation analyses were calculated with msqrobsum. I performed differential gene expression and gene set enrichment analysis (GSEA) with the GSEA method. Genes were ranked according the signed –log10 (BH adjusted p-value) obtained by looking at the diet effect in female or male in each strain separately. For variance analysis, we used the type II sum of squares, which preserves the principle of marginality and is independent of the listing order of the model parameters. The variantPartition package was used to compute the variance explained by defined parameters for transcriptomic data.
I demonstrated the accumulation of aggregation-prone protein in the muscle with diet and aging, and the link with mitochondrial metabolism. I furthermore contributed to research that investigates potential avenues for treating this protein aggregation by boosting mitochondrial metabolism (tetracyclines) or targeting the de novo sphingolipid synthesis pathway.
The results were disseminated in the following scientific publications; all of which are gold open access:
1 Evidence for a neuromuscular circuit involving hypothalamic Interleukin-6 signaling in the control of skeletal muscle metabolism. Science Advances. (2022). PMID: 35905178
2 Genetic background and sex control the outcome of high-fat diet feeding in mice. iScience. (2022). PMID: 35677645
3 The mouse metallomic landscape of aging and metabolism. (2022). PMID: 35105883
4 Inhibition of sphingolipid de novo synthesis counteracts muscular dystrophy. Science Advances. (2021). PMID: 35089797
I disseminated my results on my own Twitter profile (@LudgerGoeminne; 149 followers) with the @EU_H2020 and @MSCActions Twitter handles and the #H2020, #MSCA and #MarieCurious hashtags. I furthermore managed the lab’s Twitter profile (@Auwerx_Lab; 1451 followers) and the lab’s web site (https://www.epfl.ch/labs/auwerx-lab/) on which I posted news related to the project. I also maintained the project’s web site (https://www.epfl.ch/labs/auwerx-lab/amyloage/).
I searched the RIAILs proteomics LC-MS files with Maxquant. Proteins were quantified with MSqRob and protein level summaries for correlation analyses were calculated with msqrobsum. I performed differential gene expression and gene set enrichment analysis (GSEA) with the GSEA method. Genes were ranked according the signed –log10 (BH adjusted p-value) obtained by looking at the diet effect in female or male in each strain separately. For variance analysis, we used the type II sum of squares, which preserves the principle of marginality and is independent of the listing order of the model parameters. The variantPartition package was used to compute the variance explained by defined parameters for transcriptomic data.
I demonstrated the accumulation of aggregation-prone protein in the muscle with diet and aging, and the link with mitochondrial metabolism. I furthermore contributed to research that investigates potential avenues for treating this protein aggregation by boosting mitochondrial metabolism (tetracyclines) or targeting the de novo sphingolipid synthesis pathway.
The results were disseminated in the following scientific publications; all of which are gold open access:
1 Evidence for a neuromuscular circuit involving hypothalamic Interleukin-6 signaling in the control of skeletal muscle metabolism. Science Advances. (2022). PMID: 35905178
2 Genetic background and sex control the outcome of high-fat diet feeding in mice. iScience. (2022). PMID: 35677645
3 The mouse metallomic landscape of aging and metabolism. (2022). PMID: 35105883
4 Inhibition of sphingolipid de novo synthesis counteracts muscular dystrophy. Science Advances. (2021). PMID: 35089797
I disseminated my results on my own Twitter profile (@LudgerGoeminne; 149 followers) with the @EU_H2020 and @MSCActions Twitter handles and the #H2020, #MSCA and #MarieCurious hashtags. I furthermore managed the lab’s Twitter profile (@Auwerx_Lab; 1451 followers) and the lab’s web site (https://www.epfl.ch/labs/auwerx-lab/) on which I posted news related to the project. I also maintained the project’s web site (https://www.epfl.ch/labs/auwerx-lab/amyloage/).
I am the first to have assessed aggregation-prone proteins in the muscles of such a diverse set of mouse strains. I showed that proteins like α-synuclein and amyloid-β accumulate in the muscles with age and diet. He further elucidated a link with mitochondrial metabolism and contributed to revealing the role of the de novo sphingolipid synthesis pathway in Duchenne muscular dystrophy. These insights significantly push forward the state of the art.
I demonstrated that aggregation-prone proteins accumulate in the muscles with high-fat diet and Western diet. I showed a link between these aggregates and mitochondrial respiratory chain composition. This opens possibilities to investigate boosting mitochondrial respiration to mediate the negative effects of diet-induced obesity in the muscle. I also elucidated important differences in the mitochondrial response to diet between men and women, which opens important new research avenues towards gender-specific treatments against obesity. Using the worm RIAILs, I helped demonstrate the usefulness of boosting the mitochondria with tetracyclines against age-related muscle decline. I furthermore contributed to a landmark study that reveals the role of de novo sphingolipid synthesis in Duchenne muscular dystrophy.
My project revealed important clues about the genetic modulators of decreased muscle function with diet and aging, and the sex-specific differences of these effects, and revealed the de novo sphingolipid synthesis pathway as a new potential target against Duchenne muscular dystrophy. Future treatments based on this research that increase muscle function in sarcopenic obesity and/or Duchenne muscular dystrophy could positively impact life quality for millions of people in the EU.
I demonstrated that aggregation-prone proteins accumulate in the muscles with high-fat diet and Western diet. I showed a link between these aggregates and mitochondrial respiratory chain composition. This opens possibilities to investigate boosting mitochondrial respiration to mediate the negative effects of diet-induced obesity in the muscle. I also elucidated important differences in the mitochondrial response to diet between men and women, which opens important new research avenues towards gender-specific treatments against obesity. Using the worm RIAILs, I helped demonstrate the usefulness of boosting the mitochondria with tetracyclines against age-related muscle decline. I furthermore contributed to a landmark study that reveals the role of de novo sphingolipid synthesis in Duchenne muscular dystrophy.
My project revealed important clues about the genetic modulators of decreased muscle function with diet and aging, and the sex-specific differences of these effects, and revealed the de novo sphingolipid synthesis pathway as a new potential target against Duchenne muscular dystrophy. Future treatments based on this research that increase muscle function in sarcopenic obesity and/or Duchenne muscular dystrophy could positively impact life quality for millions of people in the EU.