An important hallmark of aging is the loss of proteostasis, which can lead to the formation of protein aggregates and mitochondrial dysfunction in neurons. Although it is well known that protein synthesis is finely regulated in the brain, especially at synapses, where mRNAs are locally translated in an activity-dependent manner, little is known as to the changes in the synaptic proteome and transcriptome during aging. Therefore, this work aims to elucidate the relationship between the transcriptome and proteome at the soma and synaptic levels during aging. Proteomic and transcriptomic data analysis reveal that, in young animals, proteins and transcripts are correlated and synaptic regulation is driven by changes in the soma. During aging, there is a decoupling between transcripts and proteins and between somatic and synaptic compartments. Furthermore, the soma-synapse gradient of ribosomal genes changes upon aging, that is, ribosomal transcripts are less abundant and ribosomal proteins are more abundant in the synaptic compartment of old mice with respect to younglings. Additionally, transcriptomics data highlight a difference in the splicing of certain synaptic mRNA with aging. Taken together, our data provide a valuable resource for the study of the aging synapse.

Gastruloids are an in vitro model that mimics key aspects of gastrulation and can be used to study implantation-stage embryonic development. Even though current protocols have contributed significantly to our understanding of developmental biology, further improvements in terms of consistency and reproducibility are still required. In this chapter, we present a detailed pre-culture protocol optimized for the generation of gastruloids from 129S1/SvImJ/ C57BL/6 mouse embryonic stem cells (mESCs). Additionally, we provide information on the steps of the protocol open to optimization and present a workflow for selecting optimal conditions and evaluating the gastruloid formation outcome when using different cell lines. Overall, this workflow facilitates a step-by-step approach toward generating gastruloids from any cell line in a highly reproducible manner by optimizing the mESC pre-culture conditions.

Osteoporosis is an increasing concern in the aging population worldwide, culminating in increased economic concerns and diminished quality of life. Similarly, disturbances of lipid metabolism and adipocytes accumulate more and more in western societies and need solutions. Adipocytes have recently attracted much interest in relation to their endocrine products, one of which is adiponectin, normally associated with beneficial effects on cardiovascular health, inflammation, and cancer. In this study, we have investigated the effect of AdipoRon, an adiponectin receptor agonist with reported anti-osteoclastic properties, on the development of osteoporosis in two different preclinical models. Contrasting to our initial hypothesis, AdipoRon treatment accelerated metabolic changes and bone loss in both models. However, AdipoRon rescued bone marrow adipocytes presence induced by glucocorticoids. Investigations on adipocyte differentiation revealed that AdipoRon potently changes adipocyte identity, by exerting opposite effects on adipocyte-gene induction depending on the time point and duration of stimulation. In conclusion, adipocyte-derived Adiponectin deserves further investigation as an autocrine mediator in musculoskeletal research.