Research of drugs against age-related diseases

Sarcopenia is a prominent disease in developed societies. It is described as an age-related pathology characterized by a progressive loss of muscle mass and strength. It is the main cause of frailty and disability in the elderly worldwide, affecting up to 50% of 80-year. Currently, no known cure is available for sarcopenia. Our laboratory collaborated with Rejuvenate Biomed, a company specialized in healthy aging, to test the effect of RJx-01, a combination drug, composed of metformin and galantamine, on sarcopenia. Metformin is a drug used against type 2 diabetes. Galantamine is commonly used in the treatment of Alzheimer’s disease. Both drugs have been linked to a decrease in all-cause mortality. The combination of these molecules has been predicted by Rejuvenate Biomed’s proprietary platform CombinAgeTM to have a synergistic effect on sarcopenia. Indeed, RJx-01 has been proven to ameliorate motor symptoms and muscle structure in C. elegans, in aged mice, as well as in inducible muscle specific OPA1 KO mice, a model of precocious aging. We decided to further characterize RJx-01 by testing the drug on murine models for acute disuse skeletal muscle atrophy. As opposed to chronic models of disuse, we aimed at studying the atrophic process during periods of limb immobilization, mimicking the condition of patients wearing casts or dealing with forced bedrest. Before proceeding with the RJx-01 tests, we decided to characterize our own model for unilateral immobilization, consisting in a 3D-printed cast. The mounting procedure is non-invasive, simply requiring a light anesthesia and a few drops of superglue. A 2-weeks period of immobilization produced little to no swelling or skin damage and induces the activation of atrophy-related genes, causing a muscle weight loss, cross-sectional area decrease and reduction of muscle force. The contralateral leg did not show signs of overload or hypertrophy when compared to free roaming littermates, offering a good internal control over the immobilized limb. The unmounting procedure is also simple, only requiring the separation of the two halves of the boot with a specialized scissor. Upon cast removal, mice can immediately reload the previously immobilized hindlimb, recovering the normal 4-legged gait. Therefore, the recovery phase can be studied, with mice effectively recovering muscle mass and force in 3 weeks. We proceeded to test RJx-01 in three groups of wild type mice. We immobilized for 2 weeks a first cohort of aged mice to test the effect of RJx-01 on acute disuse skeletal muscle atrophy as opposed to chronic. We also performed the same experiment in young mice to study possible age-dependent differences in RJx-01. One last cohort of young mice was again immobilized for 2 weeks but allowed to recover for 1 week, to inquire possible effects related to the recovery phase. The preliminary studies showed that RJx-01 treatment resulted in a reduced tendency of percentage muscle loss and had no significant effect on strength after disuse in old mice. In young mice, RJx-01 treatment resulted in a reduced tendency of percentage muscle loss and significantly reduced absolute muscle force loss compared to the untreated group after disuse. RJx-01 had no significant effect on these parameters after one week recovery. Further, we explored the use of C. elegans to study Parkinson’s Disease (PD). Preliminary tests were executed on C. elegans PD models to select a suitable protocol for future drug testing. C. elegans strains expressing human α-synuclein were investigated, monitoring declines in locomotion and survival, and progression of α-synuclein aggregates formation. One strain of YFP-tagged dopaminergic neurons worms was used to study the natural degeneration of dopaminergic neurons during aging, as well as after exposure to a dopaminergic neurons-selective toxin. These tests led to the writing of replicable protocols suitable for drug testing in C. elegans models.