Background Amyotrophic lateral sclerosis (ALS) is marked by the deterioration of both cortical and spinal cord motor neurons. Despite the underlying causes of the disease remain elusive, there has been a growing attention on the well-being of cortical motor neurons in recent times. Focused ultrasound combined with microbubbles (FUS/MB) for opening the blood–brain barrier (BBB) provides a means for drug delivery to specific brain regions, holding significant promise for the treatment of neurological disorders. Objectives We aim to explore the outcomes of FUS/MB-mediated delivery of arctiin (Arc), a natural compound with anti-inflammatory activities, to the cerebral motor cortex area by using a transgenic ALS mouse model. Methods The ALS mouse model with the SOD1 G93A mutation was used and subjected to daily Arc administration with FUS/MB treatment twice a week. After six-week treatments, the motor performance was assessed by grip strength, wire hanging, and climbing-pole tests. Mouse brains, spinal cords and gastrocnemius muscle were harvested for histological staining. Results Compared with the mice given Arc administration only, the combined treatments of FUS/MB with Arc induced further mitigation of the motor function decline, accompanied by improved health of the gastrocnemius muscle. Furthermore, notable neuroprotective effect was evidenced by the amelioration of motor neuron failure in the cortex and lumbar spinal cord. Conclusion These preliminary results indicated that the combined treatment of FUS/MB and arctiin exerted a potentially beneficial effect on neuromuscular function in the ALS disease.
Sodium Danshensu (SDSS) is extracted from Salvia miltiorrhiza and has many pharmacological effects. However, little is known about its effects on muscle fiber formation and metabolism. Here, we aimed to investigated the role and molecular mechanisms of SDSS in modulating the formation of skeletal muscle fiber. C2C12 cells were incubated in differentiation medium with or without SDSS for 4 days. C57BL/6 mice were orally administered SDSS by gavage once a day for 8 weeks. Grip strength, treadmill, muscle weight, western blotting, qPCR, immunofluorescence staining and H&E staining were performed. SDSS target proteins were searched through drug affinity responsive target stability (DARTS) and mass spectrometry analysis. Furthermore, molecular docking was carried out for Pyruvate kinase M1 (PKM1). The effect of PKM1 on myosin heavy chain (MyHCs) gene expression was verified by knockdown of PKM1 experiment. SDSS induced oxidative muscle fiber-related gene expression, and inhibited glycolytic fiber-related gene expression in C2C12 cells. Muscle mass, the percentage of slow oxidative fibers, succinic dehydrogenase activity, muscle endurance, glucose tolerance, and the expression of the MyHC1 and MyHC2a genes increased while MyHC2b expression, lactate dehydrogenase activity, and the percentage of glycolytic muscle fibers decreased in SDSS-treated mice. Mechanistically, SDSS bound to the pyruvate kinase PKM1 and significantly repressed its activity. PKM1 inhibited MyHC1 and MyHC2a expression but promoted MyHC2b expression. SDSS also significantly attenuated the effects of PKM1 on muscle fiber-related gene expression in C2C12 cells. Our findings indicate that SDSS promotes muscle fiber transformation from the glycolytic type to the oxidative type by inhibiting PKM1 activity, which provide a new idea for treating muscle atrophy, muscle metabolism diseases and improving animal meat production.