Passive Transfer of Blood Sera from ALS Patients with Identified Mutations Results in Elevated Motoneuronal Calcium Level and Loss of Motor Neurons in the Spinal Cord of Mice.

Tamás F Polgár,József I Engelhardt,Márta Széll,Krisztina Spisák,Laura Körmöczy,Izabella Obál,Bernát Nógrádi,Kornélia Tripolszki,Roland Patai,László Siklós,Valéria Meszlényi

doi:10.3390/ijms22189994

Abstract

Introduction: Previously, we demonstrated the degeneration of axon terminals in mice after repeated injections of blood sera from amyotrophic lateral sclerosis (ALS) patients with identified mutations. However, whether a similar treatment affects the cell body of motor neurons (MNs) remained unresolved. Methods: Sera from healthy individuals or ALS patients with a mutation in different ALS-related genes were intraperitoneally injected into ten-week-old male Balb/c mice (n = 3/serum) for two days. Afterward, the perikaryal calcium level was measured using electron microscopy. Furthermore, the optical disector method was used to evaluate the number of lumbar MNs. Results: The cytoplasmic calcium level of the lumbar MNs of the ALS-serum-treated mice, compared to untreated and healthy-serum-treated controls, was significantly elevated. While injections of the healthy serum did not reduce the number of MNs compared to the untreated control group, ALS sera induced a remarkable loss of MNs. Discussion: Similarly to the distant motor axon terminals, the injection of blood sera of ALS patients has a rapid degenerative effect on MNs. Analogously, the magnitude of the evoked changes was specific to the type of mutation; furthermore, the degeneration was most pronounced in the group treated with sera from ALS patients with a mutation in the chromosome 9 open reading frame 72 gene.

Highlights

We demonstrated the degeneration of axon terminals in mice after repeated injections of blood sera from amyotrophic lateral sclerosis (ALS) patients with identified mutations
Similar changes of the motor axon terminals could be observed in a passive transfer model of the disease, i.e., after injecting the animals with purified immunoglobulin G (IgG) [19] or whole sera obtained from sporadic ALS patients [20]
Since the whole serum was used for inoculation in this study, the presence of immunoglobulins which are partially responsible for the neuronal degeneration was visualized using immunohistochemistry [22]

Summary

Introduction

Amyotrophic lateral sclerosis (ALS) is one of the most common yet still incurable disorders affecting, primarily, the motor nervous system [1]. Similar changes of the motor axon terminals could be observed in a passive transfer model of the disease, i.e., after injecting the animals with purified immunoglobulin G (IgG) [19] or whole sera obtained from sporadic ALS patients [20]. In both models, the demonstrated calcium increase in the spinal MNs implied the importance of the elevated calcium in the pathomechanism of the disease. The number of MNs in the ventrolateral motor pool in the lumbar spinal cord was determined using the optical disector method, and the calcium content of these cells was analyzed electron microscopically

Results

Ethical Approvals and Consent to Participate

Patients

Counting the Lumbar Motor Neurons on Histological Sections

Quantification of the Intracellular Calcium Level in the Spinal Motor Neurons

Statistical Analysis