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Updated: Jul 16, 2025
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Altered Expression of Autophagy Biomarkers in Hippocampal Neurons in a Multiple Sclerosis Animal Model
Sabrina Ceccariglia1, Diego Sibilia1, Ornella Parolini1,2
1Dipartimento di Scienze della Vita e Sanità Pubblica, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
Abstract:
Multiple Sclerosis (MS) is a chronic inflammatory disease that affects the brain and spinal cord. Inflammation, demyelination, synaptic alteration, and neuronal loss are hallmarks detectable in MS. Experimental autoimmune encephalomyelitis (EAE) is an animal model widely used to study pathogenic aspects of MS. Autophagy is a process that maintains cell homeostasis by removing abnormal organelles and damaged proteins and is involved both in protective and detrimental effects that have been seen in a variety of human diseases, such as cancer, neurodegenerative diseases, inflammation, and metabolic disorders. This study is aimed at investigating the autophagy signaling pathway through the analysis of the main autophagic proteins including Beclin-1, microtubule-associated protein light chain (LC3, autophagosome marker), and p62 also called sequestosome1 (SQSTM1, substrate of autophagy-mediated degradation) in the hippocampus of EAE-affected mice. The expression levels of Beclin-1, LC3, and p62 and the Akt/mTOR pathway were examined by Western blot experiments. In EAE mice, compared to control animals, significant reductions of expression levels were detectable for Beclin-1 and LC3 II (indicating the reduction of autophagosomes), and p62 (suggesting that autophagic flux increased). In parallel, molecular analysis detected the deregulation of the Akt/mTOR signaling. Immunofluorescence double-labeling images showed co-localization of NeuN (neuronal nuclear marker) and Beclin-1, LC3, and p62 throughout the CA1 and CA3 hippocampal subfields. Taken together, these data demonstrate that activation of autophagy occurs in the neurons of the hippocampus in this experimental model.
Insights
Autophagy signaling in the hippocampus is altered in experimental autoimmune encephalomyelitis (EAE), a model for Multiple Sclerosis (MS). This study reveals increased autophagic flux in neurons, suggesting a role for autophagy in MS pathogenesis.
Area of Science:
- Neuroscience
- Cell Biology
- Immunology
Background:
- Multiple Sclerosis (MS) is a chronic inflammatory neurological disease impacting the brain and spinal cord.
- Key pathological features of MS include inflammation, demyelination, synaptic alteration, and neuronal loss.
- Autophagy, a cellular degradation process, plays complex roles in various diseases, including neurodegeneration and inflammation.
Purpose of the Study:
- To investigate the autophagy signaling pathway in the hippocampus of mice with experimental autoimmune encephalomyelitis (EAE), an MS model.
- To analyze the expression of key autophagy proteins (Beclin-1, LC3, p62) and the Akt/mTOR pathway in EAE hippocampi.
- To determine the cellular localization of autophagy markers within hippocampal neurons in EAE.
Main Methods:
- Western blot analysis was used to quantify protein levels of Beclin-1, LC3, p62, and components of the Akt/mTOR pathway.
- Immunofluorescence double-labeling was employed to visualize the co-localization of autophagy markers with neuronal markers (NeuN).
- Experiments were conducted on hippocampi from EAE-affected mice and control animals.
Main Results:
- EAE mice showed reduced expression of Beclin-1 and LC3 II, indicating fewer autophagosomes.
- A decrease in p62 levels in EAE mice suggested an increase in autophagic flux.
- Deregulation of the Akt/mTOR signaling pathway was observed in EAE hippocampi.
- Autophagy markers (Beclin-1, LC3, p62) were found to co-localize with neurons in the CA1 and CA3 hippocampal subfields.
Conclusions:
- Autophagy is activated in hippocampal neurons during experimental autoimmune encephalomyelitis.
- The findings suggest a significant role for autophagy modulation in the neuropathology of MS.
- These results provide insights into the cellular mechanisms underlying neuronal changes in MS models.
