The Dilemma of the Clinical Trialist in Amyotrophic Lateral Sclerosis

Redox profiles of amyotrophic lateral sclerosis lymphoblasts with or without known SOD1 mutations

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing neurodegenerative disease that affects motor neurons. This disease is associated with oxidative stress especially in mutant superoxide dismutase 1 (mutSOD1) patients. However, less is known for the most prevalent sporadic ALS form, due to a lack of disease models. Here, we studied oxidative stress profiles in lymphoblasts from ALS patients with mutSOD1 or unknown (undSOD1) mutations.

METHODS

mutSOD1 and undSOD1 lymphoblasts, as well as sex/age-matched controls (3/group) were obtained from Coriell and divided into 46 years-old-men (C1), 46 years-old-women (C2) or 26/27 years-old-men (C3) cohorts. Growth curves were performed, and several parameters associated with redox homeostasis were evaluated, including SOD activity and expression, general oxidative stress levels, lipid peroxidation, response to oxidative stimulus, glutathione redox cycle, catalase expression, and activity, and Nrf2 transcripts. Pooled (all cohorts) and paired (intra-cohort) statistical analyses were performed, followed by clustering and principal component analyses (PCA).

RESULTS

Although a high heterogeneity among lymphoblast redox profiles was found between cohorts, clustering analysis based on 7 parameters with high chi-square ranking (total SOD activity, oxidative stress levels, catalase transcripts, SOD1 protein levels, metabolic response to mM concentrations of tert-butyl hydroperoxide, glutathione reductase activity, and Nrf2 transcript levels) provided a perfect cluster segregation between samples from healthy controls and ALS (undSOD1 and mutSOD1), also visualized in the PCA.

CONCLUSIONS

Our results show distinct redox signatures in lymphoblasts from mutSOD1, undSOD1 and healthy controls that can be used as therapeutic targets for ALS drug development.

Integrative Profiling of Amyotrophic Lateral Sclerosis Lymphoblasts Identifies Unique Metabolic and Mitochondrial Disease Fingerprints

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with a rapid progression and no effective treatment. Metabolic and mitochondrial alterations in peripheral tissues of ALS patients may present diagnostic and therapeutic interest. We aimed to identify mitochondrial fingerprints in lymphoblast from ALS patients harboring SOD1 mutations (mutSOD1) or with unidentified mutations (undSOD1), compared with age-/sex-matched controls. Three groups of lymphoblasts, from mutSOD1 or undSOD1 ALS patients and age-/sex-matched controls, were obtained from Coriell Biobank and divided into 3 age-/sex-matched cohorts. Mitochondria-associated metabolic pathways were analyzed using Seahorse MitoStress and ATP Rate assays, complemented with metabolic phenotype microarrays, metabolite levels, gene expression, and protein expression and activity. Pooled (all cohorts) and paired (intra-cohort) analyses were performed by using bioinformatic tools, and the features with higher information gain values were selected and used for principal component analysis and Naïve Bayes classification. Considering the group as a target, the features that contributed to better segregation of control, undSOD1, and mutSOD1 were found to be the protein levels of Tfam and glycolytic ATP production rate. Metabolic phenotypic profiles in lymphoblasts from ALS patients with mutSOD1 and undSOD1 revealed unique age-dependent different substrate oxidation profiles. For most parameters, different patterns of variation in experimental endpoints in lymphoblasts were found between cohorts, which may be due to the age or sex of the donor. In the present work, we investigated several metabolic and mitochondrial hallmarks in lymphoblasts from each donor, and although a high heterogeneity of results was found, we identified specific metabolic and mitochondrial fingerprints, especially protein levels of Tfam and glycolytic ATP production rate, that may have a diagnostic and therapeutic interest.

Delayed onset of inherited ALS by deletion of the BDNF receptor TrkB.T1 is non-cell autonomous

The pathophysiology of Amyotrophic Lateral Sclerosis (ALS), a disease caused by the gradual degeneration of motoneurons, is still largely unknown. Insufficient neurotrophic support has been cited as one of the causes of motoneuron cell death. Neurotrophic factors such as BDNF have been evaluated in ALS human clinical trials, but yielded disappointing results attributed to the poor pharmacokinetics and pharmacodynamics of BDNF. In the inherited ALS G93A SOD1 animal model, deletion of the BDNF receptor TrkB.T1 delays spinal cord motoneuron cell death and muscle weakness through an unknown cellular mechanism. Here we show that TrkB.T1 is expressed ubiquitously in the spinal cord and its deletion does not change the SOD1 mutant spinal cord inflammatory state suggesting that TrkB.T1 does not influence microglia or astrocyte activation. Although TrkB.T1 knockout in astrocytes preserves muscle strength and co-ordination at early stages of disease, its specific conditional deletion in motoneurons or astrocytes does not delay motoneuron cell death during the early stage of the disease. These data suggest that TrkB.T1 may limit the neuroprotective BDNF signaling to motoneurons via a non-cell autonomous mechanism providing new understanding into the reasons for past clinical failures and insights into the design of future clinical trials employing TrkB agonists in ALS.

Fibroblast bioenergetics to classify amyotrophic lateral sclerosis patients

BACKGROUND

The objective of this study was to investigate cellular bioenergetics in primary skin fibroblasts derived from patients with amyotrophic lateral sclerosis (ALS) and to determine if they can be used as classifiers for patient stratification.

METHODS

We assembled a collection of unprecedented size of fibroblasts from patients with sporadic ALS (sALS, n = 171), primary lateral sclerosis (PLS, n = 34), ALS/PLS with C9orf72 mutations (n = 13), and healthy controls (n = 91). In search for novel ALS classifiers, we performed extensive studies of fibroblast bioenergetics, including mitochondrial membrane potential, respiration, glycolysis, and ATP content. Next, we developed a machine learning approach to determine whether fibroblast bioenergetic features could be used to stratify patients.

RESULTS

Compared to controls, sALS and PLS fibroblasts had higher average mitochondrial membrane potential, respiration, and glycolysis, suggesting that they were in a hypermetabolic state. Only membrane potential was elevated in C9Orf72 lines. ATP steady state levels did not correlate with respiration and glycolysis in sALS and PLS lines. Based on bioenergetic profiles, a support vector machine (SVM) was trained to classify sALS and PLS with 99% specificity and 70% sensitivity.

CONCLUSIONS

sALS, PLS, and C9Orf72 fibroblasts share hypermetabolic features, while presenting differences of bioenergetics. The absence of correlation between energy metabolism activation and ATP levels in sALS and PLS fibroblasts suggests that in these cells hypermetabolism is a mechanism to adapt to energy dissipation. Results from SVM support the use of metabolic characteristics of ALS fibroblasts and multivariate analysis to develop classifiers for patient stratification.

[Dimebon delays the onset of symptoms of FUS-proteinopathy in transgenic mice]

AIM

To evaluate an effect of dimebon on the onset of symptomatic stage in FUS.1-513 transgenic mice - a new genetic model of neurodegeneration, and to study the dynamics of disease progression in the terminal stage.

MATERIAL AND METHODS

The study was carried out on males of line FUS1-513 with the contribution of genes from CD1 strains. Mice of the experimental group (n=28) received dimebon with water in the concentration of 70 mcg/ml starting from the 35th day of life. The control group (n=25) did not receive the drug. Age, body mass of animals at the start of symptomatic stage and duration of symptomatic stage were assessed.

RESULTS

Application of dimebon can delay the onset of the manifestation of clinical symptoms of the neurodegenerative process in the experimental group (127.6±4.6 days) compared to the control group (110.6±4.2 days). The body mass was similar in both groups.

CONCLUSION

Dimebon leads to an increase in the duration of presymptomatic stage and delays the manifestation of clinical symptoms. The changes in the dynamics of the pathological process in the symptomatic stage are not detected.

A Phase 2A randomized, double-blind, placebo-controlled pilot trial of GM604 in patients with Amyotrophic Lateral Sclerosis (ALS Protocol GALS-001) and a single compassionate patient treatment (Protocol GALS-C)

Background Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that lacks effective treatment options. Genervon has discovered and developed GM604 (GM6) as a potential ALS therapy. GM6 has been modeled upon an insulin receptor tyrosine kinase binding motoneuronotrophic factor within the developing central nervous system. Methods This was a 2-center phase 2A, randomized, double-blind, placebo-controlled pilot trial with 12 definite ALS patients diagnosed within 2 years of disease onset. Patients received 6 doses of GM604 or placebo, administered as slow IV bolus injections (3x/week, 2 consecutive weeks). Objectives were to assess the safety and efficacy of GM604 based on ALSFRS-R, FVC and selected biomarkers (TDP-43, Tau and SOD1, pNFH). This report also includes results of compassionate treatment protocol GALS-C for an advanced ALS patient. Results Definite ALS patients were randomized to one of two treatment groups (GM604, n = 8; placebo, n = 4). 2 of 8 GM604-treated patients exhibited mild rash, but otherwise adverse event frequency was similar in treated and placebo groups. GM604 slowed functional decline (ALSFRS-R) when compared to a historical control (P = 0.005). At one study site, a statistically significant difference between treatment and control groups was found when comparing changes in respiratory function (FVC) between baseline and week 12 (P = 0.027). GM604 decreased plasma levels of key ALS biomarkers relative to the placebo group (TDP-43, P = 0.008; Tau, P = 0.037; SOD1, P = 0.009). The advanced ALS patient in compassionate treatment demonstrated improved speech, oral fluid consumption, mouth suction with GM604 treatment and biomarker improvements. Conclusions We observed favorable shifts in ALS biomarkers and improved functional measures during the Phase 2A study as well as in an advanced ALS patient. Although a larger trial is needed to confirm these findings, the present data are encouraging and support GM604 as an ALS drug candidate.