Fragment C of tetanus toxin, more than a carrier. Novel perspectives in non-viral ALS gene therapy

Abstract

The non-toxic carboxy-terminal fragment of tetanus toxin heavy chain (TTC) has been implicated in the activation of cascades responsible for trophic actions and neuroprotection by inhibition of apoptosis. Previous in vitro studies have described signalling pathways that underlie the administration of TTC to neurons. We investigated whether these properties were maintained in a mouse model of neurodegenerative disease. Naked DNA encoding for TTC was injected intramuscularly and neuromuscular function and clinical behaviour were monitored until endstage in the transgenic SOD1G93A mouse model that expresses a mutant variant of human superoxide dismutase 1 (SOD1). Our results indicate that TTC treatment ameliorated the decline of hindlimb muscle innervation, significantly delayed the onset of symptoms and functional deficits, improved spinal motor neuron survival, and prolonged lifespan. Furthermore, we found that caspase-1 and caspase-3 proapoptotic genes were down-regulated in the spinal cord of treated mice. Western blot analysis showed that the active form of caspase-3 was also down-regulated after TTC treatment and survival signals, such as the significant phosphorylation of serine/threonine protein kinase Akt, were also detected. These results suggest that fragment C of tetanus toxin, TTC, provides a potential therapy for neurodegenerative diseases.

Sigma-1R Agonist Improves Motor Function and Motoneuron Survival in ALS Mice

“…For colocalizations, spinal MNs were labeled with Cy2-or Cy3-conjugated fluorotracer Nissl staining (1:200, Life Technologies, Grand Island, NY, USA). To quantify astroglial and microglial immunoreactivity, microphotographs of the grey matter of the ventral horn were taken at×400 and, after defining the threshold for background correction, the integrated density of glial fibrillary acidic protein (GFAP) or ionized calcium binding adaptor molecule 1 (Iba1) labeling was measured using ImageJ software (National Institutes of Health, Bethesda, MA, USA) [27,28]. The integrated density is the area above the threshold for the mean density minus the background.…”

Introductory Chapter: Introduction to Update in Amyotrophic Lateral Sclerosis and Review of this Condition in Sportsmen

“…Definitively, the neuroprotective role of fragment C has shed light on the understanding of the disease's neurodegeneration processes and the study of this promising property of TTC can be extended to other neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease and spinal muscular atrophy [75]. In summary, a successful neuroprotective treatment could transform neurodegenerative diseases from a relentless progressive and disabling disease to a problem that can be managed with only a modest effect on quality of life [76].…”

Gene Therapy Based on Fragment C of Tetanus Toxin in ALS: A Promising Neuroprotective Strategy for the Bench to the Bedside Approach

“…More recently, the nature of TTC described by Longstreth and colleagues [62] and Larsen and colleagues [63], based on its stability to reach motor neurons specifically through the retrograde axonal transport system, has been reinforced as a potential neuroprotective agent in previous in vivo studies of gene and protein expression after injection of plasmid-DNA in transgenic SOD1 G93A mice, which carries the mutation G93A in human superoxide dismutase 1 (SOD1) [64]. These studies suggested that intramuscular naked-DNA TTC gene therapy administered into neurodegenerative mouse model delayed the onset of symptoms (by approximately 5 days), prolonged survival (by approximately 13 days) and improved the motor function activity in TTC-treated mice throughout disease progression, by increasing numbers of surviving motor neurons (Figure 2).…”

“…These studies suggested that intramuscular naked-DNA TTC gene therapy administered into neurodegenerative mouse model delayed the onset of symptoms (by approximately 5 days), prolonged survival (by approximately 13 days) and improved the motor function activity in TTC-treated mice throughout disease progression, by increasing numbers of surviving motor neurons (Figure 2). Apart from functional and survival results obtained in vivo in transgenic SOD1 G93A mice, the electrophysiological studies showed that, from three to four months of age, TTC treatment played a partial protective effect as demonstrated by the lower decline in amplitudes of the M waves, improvement in motor behavioral tests, and increased survival of motor neurons in the TTC-treated animals' lumbar spinal cord [64] (Figure 3). Interestingly, TTC administration can also affect antiapoptic pathways by means of calciumrelated mechanisms [64].…”

“…Apart from functional and survival results obtained in vivo in transgenic SOD1 G93A mice, the electrophysiological studies showed that, from three to four months of age, TTC treatment played a partial protective effect as demonstrated by the lower decline in amplitudes of the M waves, improvement in motor behavioral tests, and increased survival of motor neurons in the TTC-treated animals' lumbar spinal cord [64] (Figure 3). Interestingly, TTC administration can also affect antiapoptic pathways by means of calciumrelated mechanisms [64]. The positive effects on motor neuron preservation, animal motor function, and survival were confirmed with studies of anti-apoptotic effects and survival signals in the spinal cords of treated animals.…”