The microbiome can influence skeletal muscle development and function, according to a new study appearing in Science Translational Medicine this week. Seeking to better understand how gut microbiota influences skeletal muscle — one of the dominant metabolic organs in the body — a team of scientists compared the skeletal muscle of wild type mice to germ-free mice lacking a gut microbiome. They found that the microbiome-deficient animals had atrophied muscles, showed decreased expression of insulin-like growth factor 1, and had reduced transcription of genes associated with skeletal muscle growth and mitochondrial function. Nuclear magnetic resonance spectrometry analysis, meanwhile, revealed that the germ-free mice had abnormal concentrations of several amino acids and reduced serum choline, the precursor of a key neurotransmitter that signals between muscle and nerve at neuromuscular junctions. Transplanting the gut microbiota from the normal mice into germ-free mice increased skeletal muscle mass among other beneficial effects.
The newly sequenced genome of the white-footed mouse Peromyscus leucopus, a major reservoir for Lyme disease, may help researchers develop new ways to combat the infection, according to a new study in Science Advances. The study's authors assembled and developed a scaffold for the P. leucopus genome, resulting in an assembly 2.45 Gb in total length, with 24 chromosome-length scaffolds harboring 97 percent of predicted genes. RNA sequencing of the mice following infection with the Lyme disease-causing bacteria Borreliella burgdorferi showed weeks-long gene expression changes in skin, but not blood, that may allow the bacteria to proliferate to levels for efficient transmission. The genome, the authors write, "will allow for experiments aimed at elucidating the mechanisms by which this widely distributed rodent serves as natural reservoir for several infectious diseases of public health importance, potentially enabling intervention strategies."