viernes, 14 de marzo de 2025

Gold Nanoparticles Conjugated with Aptamers for Targeted microRNA Delivery Promote Dystrophic Muscle Regeneration

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Duchenne muscular dystrophy is a genetic disorder characterized by the progressive loss of muscle mass due to mutations in the gene coding for dystrophin, a protein essential for muscle stability. In the absence of this functional protein, muscles cannot operate or repair properly, leading to deterioration of skeletal, cardiac, and pulmonary muscles.

Under normal conditions, when a healthy muscle is damaged, satellite cells are activated, differentiate, and contribute to muscle regeneration. This process helps maintain muscle integrity. However, in Duchenne muscular dystrophy, dystrophin is defective, making muscle fibers more vulnerable to damage. As a result, satellite cells remain continuously activated, leading to inflammation and, eventually, their exhaustion and death. Since satellite cells fail to differentiate, the muscle loses its ability to regenerate and, over time, is replaced by fibrotic and adipose tissue, contributing to the progressive deterioration of muscle tissue characteristic of the disease.

MicroRNAs are a class of RNA molecules involved in gene regulation that play crucial roles in the post-transcriptional regulation of genes. They inhibit messenger RNA (mRNA), preventing the production of defective proteins.  However, delivering them through the bloodstream is challenging due to their low stability and poor cellular penetration.

 A research team designed a strategy to treat muscular dystrophy using gold nanoparticles (AuNPs) as vehicles to transport therapeutic microRNAs into muscle cells. To specifically recognize these cells, the nanoparticles were functionalized with molecules called aptamers, which identify the α7/β1 integrin, a highly specific surface receptor expressed by muscle progenitors and differentiated myofibers, but virtually absent in other organs or tissues.

Once the system enters muscle stem cells, the nanoparticles release the microRNAs, which inhibit mRNA translation, preventing the synthesis of mutated (defective) dystrophin. As a result, satellite cells are not excessively activated but instead function in a regulated manner. 

The study investigated the system's activity in cellular and animal models, where muscle regeneration was observed at the cellular level, as well as functional recovery. The muscles of the treated mice improved and strengthened after treatment, increasing the functional capacity of the animals.


For further information, refer to: Nature Communications

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