NMJ-Analyser identifies subtle early changes in mouse models of neuromuscular disease

Abstract

The neuromuscular junction (NMJ) is the peripheral synapse formed between a motor neuron axon terminal and a muscle fibre. NMJs are thought to be the primary site of peripheral pathology in many neuromuscular diseases, but innervation/denervation status is often assessed qualitatively with poor systematic criteria across studies, and separately from 3D morphological structure. Here, we describe the development of ‘NMJ-Analyser’, to comprehensively screen the morphology of NMJs and their corresponding innervation status automatically. NMJ-Analyser generates 29 biologically relevant features to quantitatively define healthy and aberrant neuromuscular synapses and applies machine learning to diagnose NMJ degeneration. We validated this framework in longitudinal analyses of wildtype mice, as well as in four different neuromuscular disease models: three for amyotrophic lateral sclerosis (ALS) and one for peripheral neuropathy. We showed that structural changes at the NMJ initially occur in the nerve terminal of mutant TDP43 and FUS ALS models. Using a machine learning algorithm, healthy and aberrant neuromuscular synapses are identified with 95% accuracy, with 88% sensitivity and 97% specificity. Our results validate NMJ-Analyser as a robust platform for systematic and structural screening of NMJs, and pave the way for transferrable, and cross-comparison and high-throughput studies in neuromuscular diseases.

Ozone modified hypothalamic signaling enhancing thermogenesis in the TDP-43A315T transgenic model of Amyotrophic Lateral Sclerosis

“…We next analised alterations in NMJs in TDP-43 A315T mice compared to age-matched WT littermate controls in responses to FA or O 3 exposure, as the hypothalamus regulates skeletal muscle metabolism 47 , and NMJ pathology is well-known in mouse models of ALS 48 . To this aim we examined the TA muscle by IHC analysis (Fig.…”

Could ozone become a complementary therapeutic approach to improve metabolic and endocrine response of ALS patients?

“…S1). O 3 exposure does not impaired the NMJs in the skeletal muscle of TDP-43 A315T mice We next studied alterations in NMJs in TDP-43 A315T mice compared to age-matched WT littermate controls at the end-stage of disease in response to FA or O 3 exposure, as NMJ pathology is well-known in mouse models of ALS 26 . To this aim we examined the TA muscle by IHC analysis (Fig.…”

Dissection, in vivo imaging and analysis of the mouse epitrochleoanconeus muscle

“…In addition to studies of synaptic degeneration (Nguyen et al, 2012), the ETA has been used to monitor NMJ development, including the processes of synapse elimination and plaque‐to‐pretzel endplate transition (Figure 5c) (Rodríguez Cruz et al, 2020), as well as terminal sprouting in response to denervation (Nguyen et al, 2012; Rogozhin et al, 2008). While most of these processes can be scored by eye, ImageJ‐based tools, such as NMJ‐morph and NMJ‐Analyser (Jones et al, 2016; Mejia Maza et al, 2021; Minty et al, 2020), provide a more objective and systematic method for analysing NMJs in a quantitative manner, which can facilitate the identification of more subtle morphological phenotypes; for example, NMJ‐Analyser was used to identify structural defects in motor nerve terminals of two different ALS mouse models at a time when no clear denervation was detectable by eye (Mejia Maza et al, 2021).…”

“…for example, NMJ-Analyser was used to identify structural defects in motor nerve terminals of two different ALS mouse models at a time when no clear denervation was detectable by eye (Mejia Maza et al, 2021).…”