Clinical implications of recent breakthroughs in amyotrophic lateral sclerosis:

Oxidative stress monitoring in iPSC-derived motor neurons using genetically encoded biosensors of H2O2

Oxidative stress plays an important role in the development of neurodegenerative diseases, being either the initiator or part of a pathological cascade that leads to the neuron’s death. Genetically encoded biosensors of oxidative stress demonstrated their general functionality and overall safety in various systems. However, there is still insufficient data regarding their use in the research of disease-related phenotypes in relevant model systems, such as human cells. Here, we establish an approach for monitoring the redox state of live motor neurons with SOD1 mutations associated with amyotrophic lateral sclerosis. Using CRISPR/Cas9, we insert genetically encoded biosensors of cytoplasmic and mitochondrial H₂O₂ in the genome of induced pluripotent stem cell (iPSC) lines. We demonstrate that the biosensors remain functional in motor neurons derived from these iPSCs and reflect the differences in the stationary redox state of the neurons with different genotypes. Moreover, we show that the biosensors respond to alterations in motor neuron oxidation caused by either environmental changes or cellular stress. Thus, the obtained platform is suitable for cell-based research of neurodegenerative mechanisms.

A longitudinal study defined circulating microRNAs as reliable biomarkers for disease prognosis and progression in ALS human patients

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease associated with motor neuron degeneration, muscle atrophy and paralysis. To date, multiple panels of biomarkers have been described in ALS patients and murine models. Nevertheless, none of them has sufficient specificity and thus the molecular signature for ALS prognosis and progression remains to be elucidated. Here we overcome this limitation through a longitudinal study, analyzing serum levels of circulating miRNAs, stable molecules that are recently used as promising biomarkers for many types of human disorders, in ALS patients during the progression of the pathology. We performed next-generation sequencing (NGS) analysis and absolute RT quantification of serum samples of ALS patients and healthy controls. The expression levels of five selected miRNAs were quantitatively analyzed during disease progression in each patient and we demonstrated that high levels of miR-206, miR-133a and miR-151a-5p can predict a slower clinical decline of patient functionality. In particular, we found that miR-206 and miR-151a-5p serum levels were significantly up-regulated at the mild stage of ALS pathology, to decrease in the following moderate and severe stages, whereas the expression levels of miR-133a and miR-199a-5p remained low throughout the course of the disease, showing a diagnostic significance in moderate and severe stages for miR-133a and in mild and terminal ones for miR-199a-5p. Moreover, we found that miR-423–3p and 151a-5p were significantly downregulated respectively in mild and terminal stages of the disease. These data suggest that these miRNAs represent potential prognostic markers for ALS disease.

Serum levels of vitamin A and 25-hydroxyvitamin D3 (25OHD3) as reflectors of pulmonary function and quality of life (QOL) in children with stable asthma: A case-control study

BACKGROUND

This study aims to explore the relationship between serum vitamin A and 25-hydroxyvitamin D3 (25OHD3) levels with pulmonary function and quality of life (QOL) in children with stable asthma.

METHODS

A total of 117 cases of children with stable asthma were assigned into the case group and 129 healthy children underwent physical examination during the same period into the control group. Electrochemiluminescence was employed to determine serum vitamin A and 25OHD3 levels. The children with stable asthma were further divided into the mild, moderate, and severe groups according to their degree of asthma. A pulmonary function meter was used to assess the pulmonary function indexes: percentage of forced expiratory volume in 1 sec/predictive value (FEV1%pred), forced vital capacity (FVC), forced expiratory volume in 1 sec/forced vital capacity (FEV1/FVC), peak expiratory flow (PEF), and maximal voluntary ventilation (MVV). The children's quality (QOL) of life with asthma was evaluated by their activities of daily living (ADLs) and Medical Research Council (MRC) scores. Pearson correlation analysis was applied to analyze the correlations of serum vitamin A and 25OHD3 levels with FEV1%pred, FVC, FEV1/FVC, PEF, MVV, ADL, and MRC.

RESULTS

Serum vitamin A and 25OHD3 levels were lower in children with stable asthma than those who were in the control group (P < .05). The severe group showed the lowest FEV1%pred, FVC, FEV1/FVC, PEF, MVV, and ADL scores, and the highest MRC score compared to the mild and moderate groups (all P < .05). Serum vitamin A and 25OHD3 levels were positively correlated with pulmonary function and ADL score in children with stable asthma, while serum vitamin A and 25OHD3 levels were negatively correlated with MRC score (all P < .05). In the case group, serum vitamin A and 25OHD3 levels were positively correlated with serum calcium and phosphorus levels (all P < .05).

CONCLUSION

These findings indicate that increased serum vitamin A and 25OHD3 levels reflect good pulmonary function and good QOL in children with stable asthma.

Protein sequestration as a normal function of long noncoding RNAs and a pathogenic mechanism of RNAs containing nucleotide repeat expansions

An emerging class of long noncoding RNAs (lncRNAs) function as decoy molecules that bind and sequester proteins thereby inhibiting their normal functions. Titration of proteins by lncRNAs has wide-ranging effects affecting nearly all steps in gene expression. While decoy lncRNAs play a role in normal physiology, RNAs expressed from alleles containing nucleotide repeat expansions can be pathogenic due to protein sequestration resulting in disruption of normal functions. This review focuses on commonalities between decoy lncRNAs that regulate gene expression by competitive inhibition of protein function through sequestration and specific examples of nucleotide repeat expansion disorders mediated by toxic RNA that sequesters RNA-binding proteins and impedes their normal functions. Understanding how noncoding RNAs compete with various RNA and DNA molecules for binding of regulatory proteins will provide insight into how similar mechanisms contribute to disease pathogenesis.

TDP-43 and FUS en route from the nucleus to the cytoplasm

Misfolded or mislocalized RNA-binding proteins (RBPs) and, consequently, altered mRNA processing, can cause neuronal dysfunction, eventually leading to neurodegeneration. Two prominent examples are the RBPs TAR DNA-binding protein of 43 kDa (TDP-43) and fused in sarcoma (FUS), which form pathological messenger ribonucleoprotein aggregates in patients suffering from amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two devastating neurodegenerative disorders. Here, we review the multiple functions of TDP-43 and FUS in mRNA processing, both in the nucleus and in the cytoplasm. We discuss how TDP-43 and FUS may exit the nucleus and how defects in both nuclear and cytosolic mRNA processing events, and possibly nuclear export defects, may contribute to neurodegeneration and ALS/FTD pathogenesis.

Geographic distributions of motor neuron disease mortality and well water use in U.S. counties

OBJECTIVE

We recently reported that U.S. mortality rates for motor neuron disease (MND) at the level of the state are associated with well water use. However, data at the state level may not accurately reflect data at the individual level. We therefore examined the association between MND mortality and well water use utilizing data from smaller geographic units that may better reflect exposure and disease at the individual level.

METHODS

We used data on age-adjusted MND mortality rates at the level of the county, obtained from the CDC, and corresponding data on the prevalence of well water use, obtained from the U.S. Geological Survey. Data were analyzed by multivariate linear regression and by Getis-Ord Gi*, a measure of spatial clustering.

RESULTS

Age-adjusted mortality rates for MND in 923 U.S. counties were significantly correlated with the prevalence of well water (p < 0.0001). 'Hot spots' of MND mortality were significantly associated with 'hot spots' of well water use (p < 0.0005).

CONCLUSIONS

These findings support the hypothesis that an agent present in well water plays an etiologic role in ALS. Further study of water use among individuals with ALS is warranted.

Precision medicine, genomics and drug discovery

The hope for precision medicine has long been on the drug discovery horizon, well before the Human Genome Project gave it promise at the turn of the 21st century. In oncology, the concept has finally been realized and is now firmly embedded in ongoing drug discovery programs, and with many recent therapies involving some level of patient/disease stratification, including some highly personalized treatments. In addition, several drugs for rare diseases have been recently approved or are in late-stage clinical development, and new delivery modalities in cell and gene therapy and oligonucleotide approaches are yielding exciting new medicines for rare diseases of unmet need. For common complex diseases, however, the GWAS-driven advances in annotation of the genetic architecture over the past decade have not led to a concomitant shift in refined treatments. Similarly, attempts to disentangle treatment responders from non-responders via genetic predictors in pharmacogenetics studies have not met their anticipated success. It is possible that common diseases are simply lagging behind due to the inherent time lag with drug discovery, but it is also possible that their inherent multifactorial nature and their etiological and clinical heterogeneity will prove more resistant to refined treatment paradigms. The emergence of population-based resources in electronic health records, coupled with the rapid expansion of mobile devices and digital health may help to refine the measurement of phenotypic outcomes to match the exquisite detail emerging at the molecular level.

Human C9ORF72 Hexanucleotide Expansion Reproduces RNA Foci and Dipeptide Repeat Proteins but Not Neurodegeneration in BAC Transgenic Mice

A non-coding hexanucleotide repeat expansion in the C9ORF72 gene is the most common mutation associated with familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). To investigate the pathological role of C9ORF72 in these diseases, we generated a line of mice carrying a bacterial artificial chromosome containing exons 1 to 6 of the human C9ORF72 gene with approximately 500 repeats of the GGGGCC motif. The mice showed no overt behavioral phenotype but recapitulated distinctive histopathological features of C9ORF72 ALS/FTD, including sense and antisense intranuclear RNA foci and poly(glycine-proline) dipeptide repeat proteins. Finally, using an artificial microRNA that targets human C9ORF72 in cultures of primary cortical neurons from the C9BAC mice, we have attenuated expression of the C9BAC transgene and the poly(GP) dipeptides. The C9ORF72 BAC transgenic mice will be a valuable tool in the study of ALS/FTD pathobiology and therapy.

Exome sequencing in amyotrophic lateral sclerosis identifies risk genes and pathways

Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment. We report the results of a moderate-scale sequencing study aimed at increasing the number of genes known to contribute to predisposition for ALS. We performed whole-exome sequencing of 2869 ALS patients and 6405 controls. Several known ALS genes were found to be associated, and TBK1 (the gene encoding TANK-binding kinase 1) was identified as an ALS gene. TBK1 is known to bind to and phosphorylate a number of proteins involved in innate immunity and autophagy, including optineurin (OPTN) and p62 (SQSTM1/sequestosome), both of which have also been implicated in ALS. These observations reveal a key role of the autophagic pathway in ALS and suggest specific targets for therapeutic intervention.

Treatment of amyotrophic lateral sclerosis: lessons learned from many failures

Amyotrophic lateral sclerosis (ALS) is one of the most complex neurodegenerative diseases, involving both cortical and spinal components of motor neuron circuitry and non-neuronal cells that support the motor neurons. There is no effective therapeutic for ALS, and compounds that have extended the lifespan of ALS mouse models have failed in clinical trials. This viewpoint discusses current information regarding the changing views about ALS and what the failures in clinical trials can teach us in the search for an effective treatment. Previous challenges and roadblocks in drug discovery for ALS are noted, and solutions to current limitations are discussed. Learning from the past and moving forward with a new mindset can translate into successful and effective treatment strategies in ALS and other related diseases.

The immunomodulatory effects of human mesenchymal stem cells on peripheral blood mononuclear cells in ALS patients

In a previous study, we reported that intrathecal injection of mesenchymal stem cells (MSCs) slowed disease progression in G93A mutant superoxide dismutase1 transgenic mice. In this study, we found that intrathecal MSC administration vastly increased the infiltration of peripheral immune cells into the spinal cord of Amyotrophic lateral sclerosis (ALS) mice (G93A mutant superoxide dismutase1 transgenic). Thus, we investigated the immunomodulatory effect of MSCs on peripheral blood mononuclear cells (PBMCs) in ALS patients, focusing on regulatory T lymphocytes (Treg ; CD4(+) /CD25(high) /FoxP3(+) ) and the mRNA expression of several cytokines (IFN-γ, TNF-α, IL-17, IL-4, IL-10, IL-13, and TGF-β). Peripheral blood samples were obtained from nine healthy controls (HC) and sixteen patients who were diagnosed with definite or probable ALS. Isolated PBMCs from the blood samples of all subjects were co-cultured with MSCs for 24 or 72 h. Based on a fluorescence-activated cell sorting analysis, we found that co-culture with MSCs increased the Treg /total T-lymphocyte ratio in the PBMCs from both groups according to the co-culture duration. Co-culture of PBMCs with MSCs for 24 h led to elevated mRNA levels of IFN-γ and IL-10 in the PBMCs from both groups. However, after co-culturing for 72 h, although the IFN-γ mRNA level had returned to the basal level in co-cultured HC PBMCs, the IFN-γ mRNA level in co-cultured ALS PBMCs remained elevated. Additionally, the levels of IL-4 and TGF-β were markedly elevated, along with Gata3 mRNA, a Th2 transcription factor mRNA, in both HC and ALS PBMCs co-cultured for 72 h. The elevated expression of these cytokines in the co-culture supernatant was confirmed via ELISA. Furthermore, we found that the increased mRNA level of indoleamine 2,3-dioxygenase (IDO) in the co-cultured MSCs was correlated with the increase in Treg induction. These findings of Treg induction and increased anti-inflammatory cytokine expression in co-cultured ALS PBMCs provide indirect evidence that MSCs may play a role in the immunomodulation of inflammatory responses when MSC therapy is targeted to ALS patients. We propose the following mechanism for the effect of mesenchymal stem cells (MSCs) administered intrathecally in amyotrophic lateral sclerosis (ALS): MSCs increase infiltration of peripheral immune cells into CNS and skew the infiltrated immune cells toward regulatory T lymphocytes (Treg ) and Th2 lymphocytes. Treg and Th2 secret anti-inflammatory cytokines such as IL-4, IL-10, and TGF-β. A series of immunomodulatory mechanism provides a new strategy for ALS treatment.

Amyotrophic lateral sclerosis: impact of pulmonary follow-up and mechanical ventilation on survival. A study of 114 cases

OBJECTIVE

To study the impact of ventilatory management and treatment on the survival of patients with amyotrophic lateral sclerosis (ALS).

METHOD

Retrospective analysis of 114 consecutive patients admitted to a general hospital, evaluating demographic data, type of presentation, clinical management, treatment with mechanical ventilation and survival.

STATISTICS

descriptive and Kaplan-Meier estimator.

RESULTS

Sixty four patients presented initial bulbar involvement. Overall mean survival after diagnosis was 28.0 months (95%CI, 21.1-34.8). Seventy patients were referred to the pulmonary specialist (61.4%) and 43 received non-invasive ventilation (NIV) at 12.7 months (median) after diagnosis. Thirty seven patients continued to receive NIV with no subsequent invasive ventilation. The mean survival of these patients was 23.3 months (95%CI, 16.7-28.8), higher in those without bulbar involvement, although below the range of significance. Survival in the 26 patients receiving programmed NIV was higher than in the 11 patients in whom this was indicated without prior pulmonary assessment (considered following diagnosis, P<.012, and in accordance with the start of ventilation, P<.004). A total of 7 patients were treated invasively; mean survival in this group was 72 months (95%CI, 14.36-129.6), median 49.6±17.5 (95%CI, 15.3-83.8), and despite the difficulties involved in home care, acceptance and tolerance was acceptable.

CONCLUSIONS

Long-term mechanical ventilation prolongs survival in ALS. Programmed pulmonary assessment has a positive impact on survival of ALS patients and is key to the multidisciplinary management of this disease.

ALS-FTD complex disorder due to C9ORF72 gene mutation: description of first Polish family

BACKGROUND

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are complex neurodegenerative disorders that can be either sporadic or familial and can overlap clinically and pathologically. We present the first Central-Eastern European family with ALS-FTD syndrome due to a C9ORF72 repeat expansion.

METHODS

We studied a family consisting of 37 family members, 6 of whom were genetically evaluated for C9ORF72 expansions. Family members were evaluated clinically, by history, and by chart review.

RESULTS

Overall, 5 generations of the family were studied, and 6 affected family members were identified. All affected members were females and had a different clinical presentation, which was ALS, FTD or both. Among the genetically evaluated subjects, 5 carried a C9ORF72 expansion; 4 of these individuals remain clinically unaffected.

CONCLUSION

Our report reveals that the hexanucleotide repeat expansion of C9ORF72, which is the most common genetic cause of ALS-FTD complex disorder, is also present in Central-Eastern Europe. Further studies are needed to assess the frequency of this expansion in the Polish population with familial as well as sporadic ALS, FTD and the ALS-FTD complex disorder.

Developments in treatments for amyotrophic lateral sclerosis via intracerebroventricular or intrathecal delivery

INTRODUCTION

Amyotrophic lateral scleroses (ALS) are neurodegenerative disorders primarily affecting the motor system. These incurable disorders are relentlessly progressive and typically limit survival to 2 - 5 years after disease onset. An improved knowledge about disease-causing genes, disease proteins and pathways has revealed considerable heterogeneity in ALS. Novel targeted therapies are being developed, but getting these beyond the BBB remains a challenge.

AREAS COVERED

The authors review the intracerebroventricular and intrathecal delivery of drugs for the treatment of ALS in preclinical and clinical studies.

EXPERT OPINION

Lack of BBB permeability should not hold back the development of promising treatments for ALS, as the available evidence suggest that direct intrathecal or intracerebroventricular administration of drug is a feasible delivery route in patients with ALS.

RNA-binding protein misregulation in microsatellite expansion disorders

RNA-binding proteins (RBPs) play pivotal roles in multiple cellular pathways from transcription to RNA turnover by interacting with RNA sequence and/or structural elements to form distinct RNA-protein complexes. Since these complexes are required for the normal regulation of gene expression, mutations that alter RBP functions may result in a cascade of deleterious events that lead to severe disease. Here, we focus on a group of hereditary disorders, the microsatellite expansion diseases, which alter RBP activities and result in abnormal neurological and neuromuscular phenotypes. While many of these diseases are classified as adult-onset disorders, mounting evidence indicates that disruption of normal RNA-protein interaction networks during embryogenesis modifies developmental pathways, which ultimately leads to disease manifestations later in life. Efforts to understand the molecular basis of these disorders has already uncovered novel pathogenic mechanisms, including RNA toxicity and repeat-associated non-ATG (RAN) translation, and current studies suggest that additional surprising insights into cellular regulatory pathways will emerge in the future.