Gamma-carboline inhibits neurodegenerative processes in a transgenic model of amyotrophic lateral sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease caused by the selective death of motor neurons. An important component in the ALS pathogenesis is the aggregation of proteins prone to conformational changes and the formation of characteristic intracellular histopathological inclu sions, on the basis of which this disease was attributed to the group of proteopathies [1]. In addition to the already known gene SOD1, recent medical genetic studies have identified a number of other genes whose mutations lead to the formation of pathogenic forms of their encoded proteins and development a neurode generative process with motoneuron lesions [2].In the sporadic ALS forms, these proteins were also found in the histopathological inclusions of the autopsy material of ALS patients. Moreover, studies performed in experimental models of ALS in trans genic mice and cell cultures provided evidence that the pathological picture of proteopathy characteristic of ALS can be reproduced in the case of metabolic disor der of only one of the key proteins [3].When studying the mechanisms of proteopathies associated with ALS and frontotemporal degenera tion, a new type of molecular cellular pathology was described. This pathology is caused by the dysfunction of the DNA/RNA binding proteins TDP43 and FUS (fused in sarcoma), which results in the inability of these proteins to form physiologically active, easily dissociating complexes with RNA (RNP). Instead, these proteins form stable RNA free structures with stably deposited aggregated forms of TDP43 and FUS proteins. This process is accompanied by changes in the intracellular compartmentalization of TDP43 and FUS and their accumulation in the pathogenic inclu sions in the cytoplasm [4][5][6][7].To model the proteopathy with the FUS protein, the aberrant forms of the FUS protein that were able to effectively form protein inclusions in cell cultures, similar to those detected in the autopsy material of ALS patients, were obtained [8]. It was found that the removal of the nuclear localization signal together with the C terminal region, which is significant for the conformational stability of the protein molecule, leads to the development of proteopathy with the involve ment of the FUS protein [5,6]. In the sequences of the gene encoding these protein regions, the largest num ber of mutations association with the hereditary forms of ALS and frontotemporal degeneration was detected. On the basis of such aberrant form of FUS, a transgenic model of proteopathy (fusopathy) was developed. Mice of this transgenic line were charac terized by the formation of histopathological inclu sions in the nervous system tissues and the develop ment of neurodegenerative process accompanied by a progressive loss of motor neurons [9]. These trans genic mice were used in this work to study the neuro protective effect of a compound of the gamma carbo line group on the progression of the model neurode generative process accompanied by primary lesion of motor neurons. It was previously shown t...

Novel Sites of Neuroprotective Action of Dimebon (Latrepirdine)

“…Moreover, the analysis of average lifespan from two other independent studies revealed that the survival of transgenes was directly dependent on the stage at which Dimebon treatment was initiated (Fig. 2) [18,50]. In each case, it was crucial to initiate treatment during the pre-symptomatic stage, suggesting that Dimebon "preconditioning" might be associated with prolonged survival of animals which correlates with results obtained by Coughlan et al [51].…”

“…A protocol of chronic administration of Dimebon in the drinking water has been successfully implemented in our laboratory for other mouse models [20,23]. Preliminary results suggest that the mean lifespan of pre-symptomatic and "symptomatic" Dimebon-treated groups was, respectively, 29 and 20 % higher than that of non-treated controls [50]. It is too early to draw definitive conclusions from these data, and molecular analyses are not yet available.…”

Transgenic mice with decreased level of the pathogenic form of human FUS protein display cognitive impairment

“…К настоящему времени выявлены химические соединения, которые способны замедлять прогрессию FUSпротеинопатии в трансгенных модельных животных, но они не способны изменять локализацию патологического процесса. Молекулярный механизм их действия не изучен [18,19]. Исследования вариантов FUS-протеинопатии существенно осложняются тем, что хотя и создан ряд моделей БАС, но практически отсутствуют животные модели с фенотипом ФТЛД [20].…”

Gamma-Carbolines Derivatives As Promising Agents for the Development of Pathogenic Therapy for Proteinopathy

“…In the nervous system of these mice, similarly to patients with FUS-associated forms of ALS, the histopathological analysis reveals an accumulation of aberrant FUS isoforms in characteristic cytoplasmic protein aggregates. Both Dimebon and its derivatives could modify, albeit with different efficacies, the progression of FUS proteinopathy in the nervous system of the FUS 1-359 mice [30]. For example, the lifespan of model animals treated with Dimebon increased statistically significantly.…”

“…For example, the lifespan of model animals treated with Dimebon increased statistically significantly. Furthermore, transfer of the FUS 1-359 mouse line from the C57Bl/6J genetic background, which was initially used in most studies in various laboratories, to the CD-1 genetic background did not affect the proteinopathy-inhibiting effect of gamma-carbolines and may not be explained by increased sensitivity of the C57Bl/6J line to gamma-carbolines [30]. In addition to an increased lifespan, the FUS 1-359 mice treated with Dimebon or its derivative were characterized by a delayed onset of model disease symptoms with the development of a pronounced ALS phenotype if administration of the compounds was initiated at early latent stages of FUS proteinopathy [31].…”