This is the web page for project AmyloAge, a Marie Skłodowska-Curie individual fellowship funded by the EU Horizon 2020 awarded to Dr. Ludger Goeminne, a postdoctoral fellow in the Auwerx Lab.
Scope of the project
Worldwide, ~13% of adults are obese and ~39% overweight. As people age, their muscle strength declines rapidly. 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.
Both from a clinical and a molecular point-of-view, sarcopenia looks a lot like inclusion body myositis, the most common acquired muscle disease in people >50 years old. Inclusion body myositis is characterized by the aggregation of the amyloid-β protein, the same protein that aggregates in the brain in patients with Alzheimer’s Disease. In Alzheimer’s Disease, all clinical trials for protein aggregation blockers have failed. Thus, we urgently need to better understand how protein aggregation relates to muscle disease.
My host lab already showed that amyloid-β accumulates in the muscles of old mice, and that this effect worsens with high-fat diet. Thus, muscle diseases such as inclusion body myositis might simply be the worst displays of a natural variation in amyloid aggregation during aging, which is influenced by environmental factors such as diet.
Mitochondria are the organelles that generate ATP, the cell’s main source of energy. My host lab recently discovered that mildly stressing the mitochondria provokes a beneficial mitochondrial stress response that reduces amyloid-β aggregation in cells, worms, and in Alzheimer transgenic mice.
Mice are excellent model organisms to study the effect of diet and genetics on muscle function because contrary to humans, the environment in their cages can be tightly controlled to avoid many known and unknown sources of unwanted variation, such as smoking, alcohol consumption, exposure to certain chemicals, and so on. But the common practice of using inbred mice, which have the same genetic backgrounds, does not account well for the large interpersonal variation in body weight in humans, where the interaction of the diet with genetics plays an important role. Mouse genetic reference populations are large collections of different inbred mouse strains that mimic the genetic variation present in the human population and allow studying the interactions between diet, age, and genetics on muscle function.
Project AmyloAge has three objectives:
- To identify and quantify the variations in genes and proteins related to protein aggregation in the muscle.
- To uncover the impact of mitochondrial activity on muscle proteostasis.
- To uncover the genetic and metabolic pathways that drive muscle deterioration with aging and diet.
We made use of different mouse genetic reference populations, which were fed a control diet vs. a high-fat diet (which contains a high fat percentage) or a Western diet (which contains high fat and sugar percentages) containing almost 1000 mice in total.
Objectives & results of the project
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, proteins that are important to help other proteins fold into a correct 3D confirmation to prevent aggregation, 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.
Publications related to the project
- Evidence for a neuromuscular circuit involving hypothalamic Interleukin-6 signaling in the control of skeletal muscle metabolism. Katashima C.K., Micheletti T., Braga R.R., Gaspar R., Goeminne L.J.E. Moura-Assis A., Crisol B., Brícola R.S., Silva V.R., Ramos C., da Rocha A.L., Tavares M.R., Simabuco F.M., Valquiria Aparecida M., Buscaratti L., Marques-Souza H., Pazos P., Gonzalez-Touceda D., Tovar S., García M., Neto J., Curi R., Hirabara S., Brum P., Prada P., de Moura L., Pauli J., Silva A., Cintra D., Velloso L. and Ropelle E. Science Advances. (2022). PMID: 35905178
- Genetic background and sex control the outcome of high-fat diet feeding in mice. Bachmann A.M., Morel J.-D. H., El Alam G., Rodríguez-López S., Imamura de Lima T., Goeminne L.J.E., Benegiamo G., Loric S., Conti M., Bou Sleiman M. and Auwerx J. iScience. (2022). PMID: 35677645
- The mouse metallomic landscape of aging and metabolism. Morel J.-D. H., Sauzéat L., Goeminne L.J.E., Jha P., Williams E., Houtkooper R.H., Aebersold R., Auwerx J. and Balter V. Nature Communications. (2022). PMID: 35105883
- Inhibition of sphingolipid de novo synthesis counteracts muscular dystrophy. Laurila P.-P., Luan P., Wohlwend M., Zanou N., Crisol B., Imamura de Lima T., Goeminne L.J.E., Gallart-Ayala H., Shong M., Ivanisevic J., Place N. and Auwerx J. Science Advances. (2021). PMID: 35089797