Neuromuscular Junction Analysis in a Mouse Model for a Peripheral Demyelinating Neuropathy

Beclin1 (Becn1) is a protein involved, among all its functions, in the regulation of autophagy and membrane trafficking – crucial processes for the development, homeostasis maintenance and regeneration of Schwann Cells (SC), the myelinating glia in the peripheral nervous system. To further investigate Becn1 role in this context, a new mouse line was generated in the lab, in which Becn1 knockout was obtained exploiting the Cre/LoxP system, expressing Cre recombinase specifically under SCs’ Mpz-promoter control. This new model developed a severe recessive demyelinating peripheral neuropathy (PN), displaying involuntary tremors, muscle atrophy and premature death. Being at the edge between nerves and muscles, neuromuscular junctions (NMJ) are crucially involved in the development of neuromuscular diseases. Hence, during my internship, I investigated NMJ morphology in this new mouse model by performing whole-mount immunofluorescence marking presynaptic compartments with anti-synaptophysin, and postsynaptic membranes’ acetylcholine-receptor clusters with α-bungarotoxin on diaphragm muscles. Morphological analysis on confocal images of NMJ were analysed by running aNMJ software. The obtained results reveal that, compared to the control ones, NMJs of Becn1-deficient mice display some altered parameters. This NMJ impairment is a relevant starting point to provide deeper insights regarding the mechanisms leading to this type of PN in future studies.