Molecular therapeutic strategies for spinal muscular atrophies: current and future clinical trials

Olesoxime protects against cisplatin-induced acute kidney injury by attenuating mitochondrial dysfunction

BACKGROUND

Mitochondrial dysfunction is a critical factor in the pathogenesis of acute kidney injury (AKI). Agents that ameliorate mitochondrial dysfunction hold potential for AKI treatment. The objective of this study was to investigate the impact of olesoxime, a novel mitochondrial-targeted agent, on cisplatin-induced AKI.

METHODS

In vivo, a cisplatin-induced AKI mouse model was established by administering a single intraperitoneal dose of cisplatin (25 mg/kg) to male C57BL/6 mice for 72 hours, followed by gavage of either olesoxime or a control solution. In vitro, human proximal tubular HK2 cells were cultured and subjected to treatments with cisplatin, either in the presence or absence of olesoxime.

RESULTS

In vivo, our findings demonstrated that olesoxime administration significantly mitigated the nephrotoxic effects of cisplatin in mice, as evidenced by reduced blood urea nitrogen (BUN) and serum creatinine (SCr) levels, improved renal histopathology, and decreased expression of renal tubular injury markers such as kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). Furthermore, olesoxime administration markedly reduced cisplatin-induced apoptosis, inflammation, and oxidative stress in the kidneys of AKI mice. Additionally, olesoxime treatment effectively restored mitochondrial function in the kidneys of AKI mice. In vitro, our results indicated that olesoxime treatment protected against cisplatin-induced apoptosis and mitochondrial dysfunction in cultured HK2 cells. Notably, cisplatin's anticancer effects were unaffected by olesoxime treatment in human cancer cells.

CONCLUSION

The results of this study suggest that olesoxime is a viable and efficient therapeutic agent in the treatment of cisplatin-induced acute kidney injury presumably by alleviating mitochondrial dysfunction.

Therapeutic Antisense Oligonucleotides in Oncology: From Bench to Bedside

Advancements in our comprehension of tumor biology and chemoresistance have spurred the development of treatments that precisely target specific molecules within the body. Despite the expanding landscape of therapeutic options, there persists a demand for innovative approaches to address unmet clinical needs. RNA therapeutics have emerged as a promising frontier in this realm, offering novel avenues for intervention such as RNA interference and the utilization of antisense oligonucleotides (ASOs). ASOs represent a versatile class of therapeutics capable of selectively targeting messenger RNAs (mRNAs) and silencing disease-associated proteins, thereby disrupting pathogenic processes at the molecular level. Recent advancements in chemical modification and carrier molecule design have significantly enhanced the stability, biodistribution, and intracellular uptake of ASOs, thereby bolstering their therapeutic potential. While ASO therapy holds promise across various disease domains, including oncology, coronary angioplasty, neurological disorders, viral, and parasitic diseases, our review manuscript focuses specifically on the application of ASOs in targeted cancer therapies. Through a comprehensive examination of the latest research findings and clinical developments, we delve into the intricacies of ASO-based approaches to cancer treatment, shedding light on their mechanisms of action, therapeutic efficacy, and prospects.

Innovative Genoceuticals in Human Gene Therapy Solutions: Challenges and Safe Clinical Trials of Orphan Gene Therapy Products

The success of gene therapy attempts is controversial and inconclusive. Currently, it is popular among the public, the scientific community, and manufacturers of Gene Therapy Medical Products. In the absence of any remedy or treatment options available for untreatable inborn metabolic orphan or genetic diseases, cancer, or brain diseases, gene therapy treatment by genoceuticals and T-cells for gene editing and recovery remains the preferred choice as the last hope. A new concept of "Genoceutical Gene Therapy" by using orphan 'nucleic acid-based therapy' aims to introduce scientific principles of treating acquired tissue damage and rare diseases. These Orphan Genoceuticals provide new scope for the 'genodrug' development and evaluation of genoceuticals and gene products for ideal 'gene therapy' use in humans with marketing authorization application (MAA). This perspective study focuses on the quality control, safety, and efficacy requirements of using 'nucleic acid-based and human cell-based new gene therapy' genoceutical products to set scientific advice on genoceutical-based 'orphan genodrug' design for clinical trials as per Western and European guidelines. The ethical Western FDA and European EMA guidelines suggest stringent legal and technical requirements on genoceutical medical products or orphan genodrug use for other countries to frame their own guidelines. The introduction section proposes lessknown 'orphan drug-like' properties of modified RNA/DNA, human cell origin gene therapy medical products, and their transgene products. The clinical trial section explores the genoceutical sources, FDA/EMA approvals for genoceutical efficacy criteria with challenges, and ethical guidelines relating to gene therapy of specific rare metabolic, cancer and neurological diseases. The safety evaluation of approved genoceuticals or orphan drugs is highlighted with basic principles and 'genovigilance' requirements (to observe any adverse effects, side effects, developed signs/symptoms) to establish their therapeutic use. Current European Union and Food and Drug Administration guidelines continuously administer fast-track regulatory legal framework from time to time, and they monitor the success of gene therapy medical product efficacy and safety. Moreover, new ethical guidelines on 'orphan drug-like genoceuticals' are updated for biodistribution of the vector, genokinetics studies of the transgene product, requirements for efficacy studies in industries for market authorization, and clinical safety endpoints with their specific concerns in clinical trials or public use.

Advances in iPSC Technology in Neural Disease Modeling, Drug Screening, and Therapy

Neurodegenerative disorders (NDs) including Alzheimer's Disease, Parkinson's Disease, Amyotrophic Lateral Sclerosis (ALS), and Huntington's disease are all incurable and can only be managed with drugs for the associated symptoms. Animal models of human illnesses help to advance our understanding of the pathogenic processes of diseases. Understanding the pathogenesis as well as drug screening using appropriate disease models of neurodegenerative diseases (NDs) are vital for identifying novel therapies. Human-derived induced pluripotent stem cell (iPSC) models can be an efficient model to create disease in a dish and thereby can proceed with drug screening and identifying appropriate drugs. This technology has many benefits, including efficient reprogramming and regeneration potential, multidirectional differentiation, and the lack of ethical concerns, which open up new avenues for studying neurological illnesses in greater depth. The review mainly focuses on the use of iPSC technology in neuronal disease modeling, drug screening, and cell therapy.

Targeted splicing therapy: new strategies for colorectal cancer

RNA splicing is the process of forming mature mRNA, which is an essential phase necessary for gene expression and controls many aspects of cell proliferation, survival, and differentiation. Abnormal gene-splicing events are closely related to the development of tumors, and the generation of oncogenic isoform in splicing can promote tumor progression. As a main process of tumor-specific splicing variants, alternative splicing (AS) can promote tumor progression by increasing the production of oncogenic splicing isoforms and/or reducing the production of normal splicing isoforms. This is the focus of current research on the regulation of aberrant tumor splicing. So far, AS has been found to be associated with various aspects of tumor biology, including cell proliferation and invasion, resistance to apoptosis, and sensitivity to different chemotherapeutic drugs. This article will review the abnormal splicing events in colorectal cancer (CRC), especially the tumor-associated splicing variants arising from AS, aiming to offer an insight into CRC-targeted splicing therapy.

Therapeutic use of calpeptin in COVID-19 infection

This perspective considers the benefits of the potential future use of the cell permeant calpain inhibitor, calpeptin, as a drug to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recent work has reported calpeptin’s capacity to inhibit entry of the virus into cells. Elsewhere, several drugs, including calpeptin, were found to be able to inhibit extracellular vesicle (EV) biogenesis. Unsurprisingly, because of similarities between viral and EV release mechanisms, calpeptin has also been shown to inhibit viral egress. This approach, identifying calpeptin, through large-scale screening studies as a candidate drug to treat COVID-19, however, has not considered the longer term likely benefits of calpain inhibition, post-COVID-19. This perspective will reflect on the capacity of calpeptin for treating long COVID by inhibiting the overproduction of neutrophil extracellular traps potentially damaging lung cells and promoting clotting, together with limiting associated chronic inflammation, tissue damage and pulmonary fibrosis. It will also reflect on the tolerated and detrimental in vivo side-effects of calpain inhibition from various preclinical studies.

Identification of potent small molecule inhibitors of SARS-CoV-2 entry

The severe acute respiratory syndrome coronavirus 2 responsible for COVID-19 remains a persistent threat to mankind, especially for the immunocompromised and elderly for which the vaccine may have limited effectiveness. Entry of SARS-CoV-2 requires a high affinity interaction of the viral spike protein with the cellular receptor angiotensin-converting enzyme 2. Novel mutations on the spike protein correlate with the high transmissibility of new variants of SARS-CoV-2, highlighting the need for small molecule inhibitors of virus entry into target cells. We report the identification of such inhibitors through a robust high-throughput screen testing 15,000 small molecules from unique libraries. Several leads were validated in a suite of mechanistic assays, including whole cell SARS-CoV-2 infectivity assays. The main lead compound, calpeptin, was further characterized using SARS-CoV-1 and the novel SARS-CoV-2 variant entry assays, SARS-CoV-2 protease assays and molecular docking. This study reveals calpeptin as a potent and specific inhibitor of SARS-CoV-2 and some variants.

Drug Discovery of Spinal Muscular Atrophy (SMA) from the Computational Perspective: A Comprehensive Review

Spinal muscular atrophy (SMA), one of the leading inherited causes of child mortality, is a rare neuromuscular disease arising from loss-of-function mutations of the survival motor neuron 1 (SMN1) gene, which encodes the SMN protein. When lacking the SMN protein in neurons, patients suffer from muscle weakness and atrophy, and in the severe cases, respiratory failure and death. Several therapeutic approaches show promise with human testing and three medications have been approved by the U.S. Food and Drug Administration (FDA) to date. Despite the shown promise of these approved therapies, there are some crucial limitations, one of the most important being the cost. The FDA-approved drugs are high-priced and are shortlisted among the most expensive treatments in the world. The price is still far beyond affordable and may serve as a burden for patients. The blooming of the biomedical data and advancement of computational approaches have opened new possibilities for SMA therapeutic development. This article highlights the present status of computationally aided approaches, including in silico drug repurposing, network driven drug discovery as well as artificial intelligence (AI)-assisted drug discovery, and discusses the future prospects.

The Ligands of Translocator Protein: Design and Biological Properties

In 2020, it is already 43 years since Braestrup and Squires discovered 18 kDa translocator protein (TSPO), known until 2006 as "peripheral benzodiazepine receptor". During this time, the functions of this receptor, which is located on the outer membrane of mitochondria, were studied in detail. One of the key functions of TSPO is the transfer of cholesterol from the outer to the inner mitochondrial membrane, which is the limiting stage in the synthesis of neurosteroids. TSPO is also involved in the transport of porphyrins, mitochondrial respiration, the opening of mitochondrial pores, apoptosis and cell proliferation. This review presents current information on the structure of TSPO, the mechanism of its participation in neurosteroidogenesis, as well as endogenous and synthetic TSPO ligands. Particular emphasis is placed on the analysis of approaches to the design of synthetic ligands and their neuropsychotropic activity in vitro and in vivo. The presented review demonstrates the promise of constructing new neuropsychotropic drugs in the series of TSPO ligands.

U7 snRNA: A tool for gene therapy

Most U-rich small nuclear ribonucleoproteins (snRNPs) are complexes that mediate the splicing of pre-mRNAs. U7 snRNP is an exception in that it is not involved in splicing but is a key factor in the unique 3' end processing of replication-dependent histone mRNAs. However, by introducing controlled changes in the U7 snRNA histone binding sequence and in the Sm motif, it can be used as an effective tool for gene therapy. The modified U7 snRNP (U7 Sm OPT) is thus not involved in the processing of replication-dependent histone pre-mRNA but targets splicing by inducing efficient skipping or inclusion of selected exons. U7 Sm OPT is of therapeutic importance in diseases that are an outcome of splicing defects, such as myotonic dystrophy, Duchenne muscular dystrophy, amyotrophic lateral sclerosis, β-thalassemia, HIV-1 infection and spinal muscular atrophy. The benefits of using U7 Sm OPT for gene therapy are its compact size, ability to accumulate in the nucleus without causing any toxic effects in the cells, and no immunoreactivity. The risk of transgene misregulation by using U7 Sm OPT is also low because it is involved in correcting the expression of an endogenous gene controlled by its own regulatory elements. Altogether, using U7 Sm OPT as a tool in gene therapy can ensure lifelong treatment, whereas an oligonucleotide or other drug/compound would require repeated administration. It would thus be strategic to harness these unique properties of U7 snRNP and deploy it as a tool in gene therapy.

In vivo and in vitro studies of antisense oligonucleotides - a review

The potential of antisense oligonucleotides in gene silencing was discovered over 40 years ago, which resulted in the growing interest in their chemistry, mechanism of action, and metabolic pathways. This review summarizes the selected mechanisms of antisense drug action, as well as therapeutics which are to date approved by the Food and Drug Administration and European Medicines Agency. Moreover, bioanalytical methods used for ASO pharmacokinetics and metabolism studies are briefly summarized. Special attention is paid to the primary pharmacokinetic properties of the different chemistry classes of antisense oligonucleotides. Moreover, in vivo and in vitro metabolic pathways of these compounds are widely described with the emphasis on the different animal models as well as in vitro models, including tissues homogenates, enzyme solutions, and human liver microsomes.

Nusinersen as a Therapeutic Agent for Spinal Muscular Atrophy

The reduction of survival motor neuron (SMN) protein causes spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disease. Nusinersen is an antisense oligonucleotide, approved by the FDA, which specifically binds to the repressor within SMN2 exon 7 to enhance exon 7 inclusion and augment production of functional SMN protein. Nusinersen is the first new oligonucleotide-based drug targeting the central nervous system for the treatment of SMA. This review of nusinersen will discuss its action mechanism, cellular uptake, trafficking mechanisms, and administration approaches to cross the blood-brain barrier. Furthermore, nusinersen clinical trials will be assessed in terms of pharmacokinetics, tolerability and safety, the clinical outcomes of multiple intrathecal doses, and a discussion on the primary and secondary endpoints.

Olesoxime improves cerebral mitochondrial dysfunction and enhances Aβ levels in preclinical models of Alzheimer's disease

BACKGROUND

Approved drugs for Alzheimer's disease (AD) only have a symptomatic effects and do not intervene causally in the course of the disease. Olesoxime (TRO19622) has been tested in AD disease models characterized by improved amyloid precursor protein processing (AβPP) and mitochondrial dysfunction.

METHODS

Three months old Thy-1-AβPP_SL (tg) and wild type mice (wt) received TRO19622 (100 mg/kg b.w.) in supplemented food pellets for 15 weeks (tg TRO19622). Mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) levels were determined in dissociated brain cells (DBC). Respiration was analyzed in mitochondria isolated from brain tissue. Citrate synthase (CS) activity and beta-amyloid peptide (Aβ_1-40) levels were determined in brain tissue. Malondialdehyde (MDA) levels were determined as an indicator for lipid peroxidation. DBC and brain homogenates were additionally stressed with Rotenone and FeCl₂, respectively. Mitochondrial respiration and Aβ_1-40 levels were also determined in HEK-AβPP_sw-cells.

RESULTS

Treatment of mice did not affect the body weight. TRO19622 was absorbed after oral treatment (plasma levels: 6,2 μg/ml). Mitochondrial respiration was significantly reduced in brains of tg-mice. Subsequently, DBC isolated from brains of tg-mice showed significantly lower MMP but not ATP levels. TRO19622 increased the activity of respiratory chain complexes and reversed complex IV (CIV) activity and MMP. Moreover, DBC isolated from brains of tg TRO19622 mice were protected from Rotenone induced inhibition of complex I activity. TRO19622 also increased the respiratory activity in HEKsw-cells. MDA basal levels were significantly higher in brain homogenates isolated from tg-mice. TRO19622 treatment had no effects on lipid peroxidation. TRO19622 increased cholesterol levels but did not change membrane fluidity of synaptosomal plasma and mitochondrial membranes isolated from brain of mice. TRO19622 significantly increased levels of Aβ_1-40 in both, in brains of tg TRO19622 mice and in HEK_sw cells.

CONCLUSIONS

TRO19622 improves mitochondrial dysfunction but enhances Aβ levels in disease models of AD. Further studies must evaluate whether TRO19622 offers benefits at the mitochondrial level despite the increased formation of Aβ, which could be harmful.

Drug treatment for spinal muscular atrophy types II and III

BACKGROUND

Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a (point) mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. This is an update of a review first published in 2009 and previously updated in 2011.

OBJECTIVES

To evaluate if drug treatment is able to slow or arrest the disease progression of SMA types II and III, and to assess if such therapy can be given safely.

SEARCH METHODS

We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. In October 2018, we also searched two trials registries to identify unpublished trials.

SELECTION CRITERIA

We sought all randomised or quasi-randomised trials that examined the efficacy of drug treatment for SMA types II and III. Participants had to fulfil the clinical criteria and have a homozygous deletion or hemizygous deletion in combination with a point mutation in the second allele of the SMN1 gene (5q11.2-13.2) confirmed by genetic analysis. The primary outcome measure was change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full-time ventilation and adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1-replacement with viral vectors are out of the scope of this review, but a summary is given in Appendix 1. Drug treatment for SMA type I is the topic of a separate Cochrane Review.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

The review authors found 10 randomised, placebo-controlled trials of treatments for SMA types II and III for inclusion in this review, with 717 participants. We added four of the trials at this update. The trials investigated creatine (55 participants), gabapentin (84 participants), hydroxyurea (57 participants), nusinersen (126 participants), olesoxime (165 participants), phenylbutyrate (107 participants), somatotropin (20 participants), thyrotropin-releasing hormone (TRH) (nine participants), valproic acid (33 participants), and combination therapy with valproic acid and acetyl-L-carnitine (ALC) (61 participants). Treatment duration was from three to 24 months. None of the studies investigated the same treatment and none was completely free of bias. All studies had adequate blinding, sequence generation and reporting of primary outcomes. Based on moderate-certainty evidence, intrathecal nusinersen improved motor function (disability) in children with SMA type II, with a 3.7-point improvement in the nusinersen group on the Hammersmith Functional Motor Scale Expanded (HFMSE; range of possible scores 0 to 66), compared to a 1.9-point decline on the HFMSE in the sham procedure group (P < 0.01; n = 126). On all motor function scales used, higher scores indicate better function. Based on moderate-certainty evidence from two studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: creatine (median change 1 higher, 95% confidence interval (CI) -1 to 2; on the Gross Motor Function Measure (GMFM), scale 0 to 264; n = 40); and combination therapy with valproic acid and carnitine (mean difference (MD) 0.64, 95% CI -1.1 to 2.38; on the Modified Hammersmith Functional Motor Scale (MHFMS), scale 0 to 40; n = 61). Based on low-certainty evidence from other single studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: gabapentin (median change 0 in the gabapentin group and -2 in the placebo group on the SMA Functional Rating Scale (SMAFRS), scale 0 to 50; n = 66); hydroxyurea (MD -1.88, 95% CI -3.89 to 0.13 on the GMFM, scale 0 to 264; n = 57), phenylbutyrate (MD -0.13, 95% CI -0.84 to 0.58 on the Hammersmith Functional Motor Scale (HFMS) scale 0 to 40; n = 90) and monotherapy of valproic acid (MD 0.06, 95% CI -1.32 to 1.44 on SMAFRS, scale 0 to 50; n = 31). Very low-certainty evidence suggested that the following interventions had little or no effect on motor function: olesoxime (MD 2, 95% -0.25 to 4.25 on the Motor Function Measure (MFM) D1 + D2, scale 0 to 75; n = 160) and somatotropin (median change at 3 months 0.25 higher, 95% CI -1 to 2.5 on the HFMSE, scale 0 to 66; n = 19). One small TRH trial did not report effects on motor function and the certainty of evidence for other outcomes from this trial were low or very low. Results of nine completed trials investigating 4-aminopyridine, acetyl-L-carnitine, CK-2127107, hydroxyurea, pyridostigmine, riluzole, RO6885247/RG7800, salbutamol and valproic acid were awaited and not available for analysis at the time of writing. Various trials and studies investigating treatment strategies other than nusinersen (e.g. SMN2-augmentation by small molecules), are currently ongoing.

AUTHORS' CONCLUSIONS

Nusinersen improves motor function in SMA type II, based on moderate-certainty evidence. Creatine, gabapentin, hydroxyurea, phenylbutyrate, valproic acid and the combination of valproic acid and ALC probably have no clinically important effect on motor function in SMA types II or III (or both) based on low-certainty evidence, and olesoxime and somatropin may also have little to no clinically important effect but evidence was of very low-certainty. One trial of TRH did not measure motor function.

Drug treatment for spinal muscular atrophy type I

BACKGROUND

Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a point mutation in the second SMN1 allele. This results in degeneration of anterior horn cells, which leads to progressive muscle weakness. By definition, children with SMA type I are never able to sit without support and usually die or become ventilator dependent before the age of two years. There have until very recently been no drug treatments to influence the course of SMA. We undertook this updated review to evaluate new evidence on emerging treatments for SMA type I. The review was first published in 2009 and previously updated in 2011.

OBJECTIVES

To assess the efficacy and safety of any drug therapy designed to slow or arrest progression of spinal muscular atrophy (SMA) type I.

SEARCH METHODS

We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. We also searched two trials registries to identify unpublished trials (October 2018).

SELECTION CRITERIA

We sought all randomised controlled trials (RCTs) or quasi-RCTs that examined the efficacy of drug treatment for SMA type I. Included participants had to fulfil clinical criteria and have a genetically confirmed deletion or mutation of the SMN1 gene (5q11.2-13.2). The primary outcome measure was age at death or full-time ventilation. Secondary outcome measures were acquisition of motor milestones, i.e. head control, rolling, sitting or standing, motor milestone response on disability scores within one year after the onset of treatment, and adverse events and serious adverse events attributable to treatment during the trial period. Treatment strategies involving SMN1 gene replacement with viral vectors are out of the scope of this review.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

We identified two RCTs: one trial of intrathecal nusinersen in comparison to a sham (control) procedure in 121 randomised infants with SMA type I, which was newly included at this update, and one small trial comparing riluzole treatment to placebo in 10 children with SMA type I. The RCT of intrathecally-injected nusinersen was stopped early for efficacy (based on a predefined Hammersmith Infant Neurological Examination-Section 2 (HINE-2) response). At the interim analyses after 183 days of treatment, 41% (21/51) of nusinersen-treated infants showed a predefined improvement on HINE-2, compared to 0% (0/27) of participants in the control group. This trial was largely at low risk of bias. Final analyses (ranging from 6 months to 13 months of treatment), showed that fewer participants died or required full-time ventilation (defined as more than 16 hours daily for 21 days or more) in the nusinersen-treated group than the control group (hazard ratio (HR) 0.53, 95% confidence interval (CI) 0.32 to 0.89; N = 121; a 47% lower risk; moderate-certainty evidence). A proportion of infants in the nusinersen group and none of 37 infants in the control group achieved motor milestones: 37/73 nusinersen-treated infants (51%) achieved a motor milestone response on HINE-2 (risk ratio (RR) 38.51, 95% CI 2.43 to 610.14; N = 110; moderate-certainty evidence); 16/73 achieved head control (RR 16.95, 95% CI 1.04 to 274.84; moderate-certainty evidence); 6/73 achieved independent sitting (RR 6.68, 95% CI 0.39 to 115.38; moderate-certainty evidence); 7/73 achieved rolling over (RR 7.70, 95% CI 0.45 to 131.29); and 1/73 achieved standing (RR 1.54, 95% CI 0.06 to 36.92; moderate-certainty evidence). Seventy-one per cent of nusinersen-treated infants versus 3% of infants in the control group were responders on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) measure of motor disability (RR 26.36, 95% CI 3.79 to 183.18; N = 110; moderate-certainty evidence). Adverse events and serious adverse events occurred in the majority of infants but were no more frequent in the nusinersen-treated group than the control group (RR 0.99, 95% CI 0.92 to 1.05 and RR 0.70, 95% CI 0.55 to 0.89, respectively; N = 121; moderate-certainty evidence). In the riluzole trial, three of seven children treated with riluzole were still alive at the ages of 30, 48, and 64 months, whereas all three children in the placebo group died. None of the children in the riluzole or placebo group developed the ability to sit, which was the only milestone reported. There were no adverse effects. The certainty of the evidence for all measured outcomes from this study was very low, because the study was too small to detect or rule out an effect, and had serious limitations, including baseline differences. This trial was stopped prematurely because the pharmaceutical company withdrew funding. Various trials and studies investigating treatment strategies other than nusinersen, such as SMN2 augmentation by small molecules, are ongoing.

AUTHORS' CONCLUSIONS

Based on the very limited evidence currently available regarding drug treatments for SMA type 1, intrathecal nusinersen probably prolongs ventilation-free and overall survival in infants with SMA type I. It is also probable that a greater proportion of infants treated with nusinersen than with a sham procedure achieve motor milestones and can be classed as responders to treatment on clinical assessments (HINE-2 and CHOP INTEND). The proportion of children experiencing adverse events and serious adverse events on nusinersen is no higher with nusinersen treatment than with a sham procedure, based on evidence of moderate certainty. It is uncertain whether riluzole has any effect in patients with SMA type I, based on the limited available evidence. Future trials could provide more high-certainty, longer-term evidence to confirm this result, or focus on comparing new treatments to nusinersen or evaluate them as an add-on therapy to nusinersen.

Development and Clinical Translation of Approved Gene Therapy Products for Genetic Disorders

The field of gene therapy is striving more than ever to define a path to the clinic and the market. Twenty gene therapy products have already been approved and over two thousand human gene therapy clinical trials have been reported worldwide. These advances raise great hope to treat devastating rare and inherited diseases as well as incurable illnesses. Understanding of the precise pathomechanisms of diseases as well as the development of efficient and specific gene targeting and delivery tools are revolutionizing the global market. Currently, human cancers and monogenic disorders are indications number one. The elevated prevalence of genetic disorders and cancers, clear gene manipulation guidelines and increasing financial support for gene therapy in clinical trials are major trends. Gene therapy is presently starting to become commercially profitable as a number of gene and cell-based gene therapy products have entered the market and the clinic. This article reviews the history and development of twenty approved human gene and cell-based gene therapy products that have been approved up-to-now in clinic and markets of mainly North America, Europe and Asia.

Recent progress in single-molecule studies of mRNA localization in vivo

From biogenesis to degradation, mRNA goes through diverse types of regulation and interaction with other biomolecules. Uneven distribution of mRNA transcripts and the diverse isoforms and modifications of mRNA make us wonder how cells manage the complexity and keep the functional integrity for the normal development of cells and organisms. Single-molecule microscopy tools have expanded the scope of RNA research with unprecedented spatiotemporal resolution. In this review, we highlight the recent progress in the methods for labeling mRNA targets and analyzing the quantitative information from fluorescence images of single mRNA molecules. In particular, the MS2 system and its various applications are the main focus of this article. We also review how recent studies have addressed biological questions related to the significance of mRNA localization in vivo. Efforts to visualize the dynamics of single mRNA molecules in live cells will push forward our knowledge on the nature of heterogeneity in RNA sequence, structure, and distribution as well as their molecular function and coordinated interaction with RNA binding proteins.

Olesoxime in neurodegenerative diseases: Scrutinising a promising drug candidate

Over the last years, the experimental compound olesoxime, a mitochondria-targeting cholesterol derivative, has emerged as a promising drug candidate for neurodegenerative diseases. Numerous preclinical studies have successfully proved olesoxime's neuroprotective properties in cell and animal models of clinical conditions such as amyotrophic lateral sclerosis, Huntington disease, Parkinson disease, peripheral neuropathy and spinal muscular atrophy. The beneficial effects were attributed to olesoxime's potential impact on oxidative stress, mitochondrial permeability transition or cholesterol homoeostasis. Although no significant benefits have been demonstrated in patients of amyotrophic lateral sclerosis, and only the first 12 months of a phase II/III clinical trial showed an improvement in motor symptoms of spinal muscular atrophy, this orphan drug may still offer undiscovered potential in the treatment of neurological diseases. In our earlier preclinical studies, we demonstrated that administration of olesoxime in mouse and rat models of Huntington disease improved psychiatric and molecular phenotypes. Aside from stabilising mitochondrial function, the drug reduced the overactivation of calpains, a class of calcium-dependent proteases entangled in neurodegenerative conditions. This observation may be credited to olesoxime's action on calcium dyshomeostasis, a further hallmark in neurodegeneration, and linked to its targets TSPO and VDAC, two proteins of the outer mitochondrial membrane associated with mitochondrial calcium handling. Further research into the mode of action of olesoxime under pathological conditions, including its effect on neuronal calcium homeostasis, may strengthen the untapped potential of olesoxime or other similar compounds as a therapeutic for neurodegenerative diseases.

Multiparametric rapid screening of neuronal process pathology for drug target identification in HSP patient-specific neurons

Axonal degeneration is a key pathology of neurodegenerative diseases, including hereditary spastic paraplegia (HSP), a disorder characterized by spasticity in the lower limbs. Treatments for HSP and other neurodegenerative diseases are mainly symptomatic. While iPSC-derived neurons are valuable for drug discovery and target identification, these applications require robust differentiation paradigms and rapid phenotypic read-outs ranging between hours and a few days. Using spastic paraplegia type 4 (SPG4, the most frequent HSP subtype) as an exemplar, we here present three rapid phenotypic assays for uncovering neuronal process pathologies in iPSC-derived glutamatergic cortical neurons. Specifically, these assays detected a 51% reduction in neurite outgrowth and a 60% increase in growth cone area already 24 hours after plating; axonal swellings, a hallmark of HSP pathology, was discernible after only 5 days. Remarkably, the identified phenotypes were neuron subtype-specific and not detectable in SPG4-derived GABAergic forebrain neurons. We transferred all three phenotypic assays to a 96-well setup, applied small molecules and found that a liver X receptor (LXR) agonist rescued all three phenotypes in HSP neurons, providing a potential drug target for HSP treatment. We expect this multiparametric and rapid phenotyping approach to accelerate development of therapeutic compounds for HSP and other neurodegenerative diseases.

AAV9 Vector: a Novel modality in gene therapy for spinal muscular atrophy

Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, is characterized by the deterioration of alpha motor neurons in the brainstem and spinal cord. Currently, there is no cure for SMA, which calls for an urgent need to explore affordable and effective therapies and to maximize patients' independence and quality of life. Adeno-associated virus (AAV) vector, one of the most promising and well-investigated vehicles for delivering transgenes, is a compelling candidate for gene therapy. Some of the hallmarks of AAVs are their nonpathogenicity, inability to incur an immune response, potential to achieve robust transgene expression, and varied tropism for several tissues of the body. Recently, these features were harnessed in a clinical trial conducted by AveXis in SMA patients, where AAV9 was employed as a vehicle for one-time administration of the SMN gene, the causative gene in SMA. The trial demonstrated remarkable improvements in motor milestones and rates of survival in the patients. This review focuses on the advent of SMA gene therapy and summarizes different preclinical studies that were conducted leading up to the AAV9-SMA trial in SMA patients.

Dissecting Motor Neuron Disease With Drosophila melanogaster

Motor Neuron Disease (MND) typically affects patients during the later stages of life, and thus, MND is having an increasingly devastating impact on diagnosed individuals, their families and society. The umbrella term MND refers to diseases which cause the progressive loss of upper and/or lower motor neurons and a subsequent decrease in motor ability such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The study of these diseases is complex and has recently involved the use of genome-wide association studies (GWAS). However, in the case of MND, it has been difficult to identify the complex genetics involved in subtypes, and functional investigation of new candidate disease genes is warranted. Drosophila is a powerful model for addressing these complex diseases. The UAS/Gal4/Gal80 system allows for the upregulation of Drosophila genes, the “knockdown” of genes and the ectopic expression of human genes or mutations in a tissue-specific manner; often resulting in Drosophila models which exhibit typical MND disease pathologies. These can then be further interrogated to identify disease-modifying genes or mutations and disease pathways. This review will discuss two common MNDs and the current Drosophila models which are being used to research their genetic basis and the different pathologies of MND.

Conserved functions of RNA-binding proteins in muscle

Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease. Although hundreds of genes predicted to bind RNA are expressed in muscles, many fewer have been functionally characterized. We present a cross-species view summarizing what is known about RNA-binding protein function in muscle, from worms and flies to zebrafish, mice and humans. In particular, we focus on alternative splicing regulated by the CELF, MBNL and RBFOX families of proteins. We discuss the systemic nature of diseases associated with loss of RNA-binding proteins in muscle, focusing on mis-regulation of CELF and MBNL in myotonic dystrophy. These examples illustrate the conservation of RNA-binding protein function and the marked utility of genetic model systems in understanding mechanisms of RNA regulation.

Alternative RNA Splicing as a Potential Major Source of Untapped Molecular Targets in Precision Oncology and Cancer Disparities

Studies of alternative RNA splicing (ARS) have the potential to provide an abundance of novel targets for development of new biomarkers and therapeutics in oncology, which will be necessary to improve outcomes for patients with cancer and mitigate cancer disparities. ARS, a key step in gene expression enabling individual genes to encode multiple proteins, is emerging as a major driver of abnormal phenotypic heterogeneity. Recent studies have begun to identify RNA splicing-related genetic and genomic variation in tumors, oncogenes dysregulated by ARS, RNA splice variants driving race-related cancer aggressiveness and drug response, spliceosome-dependent transformation, and RNA splicing-related immunogenic epitopes in cancer. In addition, recent studies have begun to identify and test, preclinically and clinically, approaches to modulate and exploit ARS for therapeutic application, including splice-switching oligonucleotides, small molecules targeting RNA splicing or RNA splice variants, and combination regimens with immunotherapies. Although ARS data hold such promise for precision oncology, inclusion of studies of ARS in translational and clinical cancer research remains limited. Technologic developments in sequencing and bioinformatics are being routinely incorporated into clinical oncology that permit investigation of clinically relevant ARS events, yet ARS remains largely overlooked either because of a lack of awareness within the clinical oncology community or perceived barriers to the technical complexity of analyzing ARS. This perspective aims to increase such awareness, propose immediate opportunities to improve identification and analysis of ARS, and call for bioinformaticians and cancer researchers to work together to address the urgent need to incorporate ARS into cancer biology and precision oncology.

Polypyrimidine tract binding protein 1 promotes lymphatic metastasis and proliferation of bladder cancer via alternative splicing of MEIS2 and PKM

Lymph node (LN) metastasis is the leading cause of bladder cancer-related mortality. Splicing factors facilitate cancer progression by modulating oncogenic variants, but it is unclear whether and how splicing factors regulate bladder cancer LN metastasis. In this study, Polypyrimidine tract binding protein 1 (PTBP1) expression was found to relate to bladder cancer LN metastasis, and was positively correlated with LN metastasis status, tumor stage, histological grade, and poor patient prognosis. Functional assays demonstrated that PTBP1 promoted bladder cancer cell migration, invasion, and proliferation in vitro, as well as LN metastasis and tumor growth in vivo. Mechanistic investigations revealed that PTBP1 upregulated MEIS2-L variant to promote metastasis and increased expression of PKM2 variant to enhance proliferation by modulating alternative mRNA splicing. Moreover, overexpression of MEIS2-L or PKM2 could rescue the oncogenic abilities of bladder cancer cells and the expression of MMP9 or CCND1 respectively after PTBP1 knockdown. In conclusion, our data demonstrate that PTBP1 induces bladder cancer LN metastasis and proliferation through an alternative splicing mechanism. PTBP1 may serve as a novel prognostic marker and therapeutic target for LN-metastatic bladder cancer.

Prediction of key gene function in spinal muscular atrophy using guilt by association method based on network and gene ontology

Guilt by association (GBA) algorithm has been widely used to predict gene functions statistically, and a network-based approach may increase the confidence and veracity of identifying molecular signatures for diseases. The aim of the present study was to suggest a gene ontology (GO)-based method by integrating the GBA algorithm and network, to identify key gene functions for spinal muscular atrophy (SMA). The inference of predicting key gene functions was comprised of four steps, preparing gene lists and sets; extracting differentially expressed genes (DEGs) using microarray data [linear models for microarray data (limma)] package; constructing a co-expression matrix on gene lists using the Spearman correlation coefficient method; and predicting gene functions by GBA algorithm. Ultimately, key gene functions were predicted according to the area under the curve (AUC) index for GO terms and the GO terms with AUC >0.7 were determined as the optimal gene functions for SMA. A total of 484 DEGs and 466 background GO terms were regarded as gene lists and sets for the subsequent analyses, respectively. The predicted results obtained from the network-based GBA approach showed 141 gene sets had a good classified performance with AUC >0.5. Most significantly, 3 gene sets with AUC >0.7 were denoted as seed gene functions for SMA, including cell morphogenesis, which is involved in differentiation and ossification. In conclusion, we have predicted 3 key gene functions for SMA compared with control utilizing network-based GBA algorithm. The findings may provide great insights to reveal pathological and molecular mechanism underlying SMA.

The RD-Connect Registry & Biobank Finder: a tool for sharing aggregated data and metadata among rare disease researchers

In rare disease (RD) research, there is a huge need to systematically collect biomaterials, phenotypic, and genomic data in a standardized way and to make them findable, accessible, interoperable and reusable (FAIR). RD-Connect is a 6 years global infrastructure project initiated in November 2012 that links genomic data with patient registries, biobanks, and clinical bioinformatics tools to create a central research resource for RDs. Here, we present RD-Connect Registry & Biobank Finder, a tool that helps RD researchers to find RD biobanks and registries and provide information on the availability and accessibility of content in each database. The finder concentrates information that is currently sparse on different repositories (inventories, websites, scientific journals, technical reports, etc.), including aggregated data and metadata from participating databases. Aggregated data provided by the finder, if appropriately checked, can be used by researchers who are trying to estimate the prevalence of a RD, to organize a clinical trial on a RD, or to estimate the volume of patients seen by different clinical centers. The finder is also a portal to other RD-Connect tools, providing a link to the RD-Connect Sample Catalogue, a large inventory of RD biological samples available in participating biobanks for RD research. There are several kinds of users and potential uses for the RD-Connect Registry & Biobank Finder, including researchers collaborating with academia and the industry, dealing with the questions of basic, translational, and/or clinical research. As of November 2017, the finder is populated with aggregated data for 222 registries and 21 biobanks.

Treatment Advances in Spinal Muscular Atrophy

PURPOSE OF REVIEW

Spinal muscular atrophy (SMA) is a genetic disorder of motor neurons in the anterior horns of the spinal cord and brainstem that results in muscle atrophy and weakness. SMA is an autosomal recessive disease linked to deletions of the SMN1 gene on chromosome 5q. Humans have a duplicate gene (SMN2) whose product can mitigate disease severity, leading to the variability in severity and age of onset of disease, and is therefore a target for drug development.

RECENT FINDINGS

Advances in preclinical and clinical trials have paved the way for novel therapeutic options for SMA patients, including many currently in clinical trials. In 2016, the first treatment for SMA has been approved in the USA, an antisense oligonucleotide that increases full-length protein product derived from SMN2. The approval of a first treatment for SMA and the rapid advances in clinical trials provide the prospect for multiple approaches to disease modification. There are several other promising therapeutics in different stages of development, based on approaches such as neuroprotection, or gene therapy.

Alternative Splicing in Breast Cancer and the Potential Development of Therapeutic Tools

Alternative splicing is a key molecular mechanism now considered as a hallmark of cancer that has been associated with the expression of distinct isoforms during the onset and progression of the disease. The leading cause of cancer-related deaths in women worldwide is breast cancer, and even when the role of alternative splicing in this type of cancer has been established, the function of this mechanism in breast cancer biology is not completely decoded. In order to gain a comprehensive view of the role of alternative splicing in breast cancer biology and development, we summarize here recent findings regarding alternative splicing events that have been well documented for breast cancer evolution, considering its prognostic and therapeutic value. Moreover, we analyze how the response to endocrine and chemical therapies could be affected due to alternative splicing and differential expression of variant isoforms. With all this knowledge, it becomes clear that targeting alternative splicing represents an innovative approach for breast cancer therapeutics and the information derived from current studies could guide clinical decisions with a direct impact in the clinical advances for breast cancer patients nowadays.

Gestational Age-Dependent Increase of Survival Motor Neuron Protein in Umbilical Cord-Derived Mesenchymal Stem Cells

BACKGROUND

Spinal muscular atrophy (SMA) is the most common genetic neurological disease leading to infant death. It is caused by loss of survival motor neuron (SMN) 1 gene and subsequent reduction of SMN protein in motor neurons. Because SMN is ubiquitously expressed and functionally linked to general RNA metabolism pathway, fibroblasts (FBs) are most widely used for the assessment of SMN expression in SMA patients but usually isolated from skin biopsy samples after the onset of overt symptoms. Although recent translational studies of SMN-targeted therapies have revealed the very limited time window for effective SMA therapies during perinatal period, the exact time point when SMN shortage became evident is unknown in human samples. In this study, we analyzed SMN mRNA and protein expression during perinatal period by using umbilical cord-derived mesenchymal stem cells (UC-MSCs) obtained from preterm and term infants.

METHODS

UC-MSCs were isolated from 16 control infants delivered at 22-40 weeks of gestation and SMA fetus aborted at 19 weeks of gestation (UC-MSC-Control and UC-MSC-SMA). FBs were isolated from control volunteer and SMA patient (FB-Control and FB-SMA). SMN mRNA and protein expression in UC-MSCs and FBs was determined by RT-qPCR and Western blot.

RESULTS

UC-MSC-Control and UC-MSC-SMA expressed the comparable level of MSC markers on their cell surface and were able to differentiate into adipocytes, osteocytes, and chondrocytes. At steady state, SMN mRNA and protein expression was decreased in UC-MSC-SMA compared to UC-MSC-Control, as observed in FB-SMA and FB-Control. In response to histone deacetylase inhibitor valproic acid, SMN mRNA and protein expression in UC-MSC-SMA and FB-SMA was increased. During perinatal development from 22 to 40 weeks of gestation, SMN mRNA and protein expression in UC-MSC-Control was positively correlated with gestational age.

CONCLUSION

UC-MSCs isolated from 17 fetus/infant of 19-40 weeks of gestation are expressed functional SMN mRNA and protein. SMN mRNA and protein expression in UC-MSCs is increased with gestational age during perinatal development.

Targets of Neuroprotection in Glaucoma

Progressive neurodegeneration of the optic nerve and the loss of retinal ganglion cells is a hallmark of glaucoma, the leading cause of irreversible blindness worldwide, with primary open-angle glaucoma (POAG) being the most frequent form of glaucoma in the Western world. While some genetic mutations have been identified for some glaucomas, those associated with POAG are limited and for most POAG patients, the etiology is still unclear. Unfortunately, treatment of this neurodegenerative disease and other retinal degenerative diseases is lacking. For POAG, most of the treatments focus on reducing aqueous humor formation, enhancing uveoscleral or conventional outflow, or lowering intraocular pressure through surgical means. These efforts, in some cases, do not always lead to a prevention of vision loss and therefore other strategies are needed to reduce or reverse the progressive neurodegeneration. In this review, we will highlight some of the ocular pharmacological approaches that are being tested to reduce neurodegeneration and provide some form of neuroprotection.

Therapeutic targeting of splicing in cancer

Recent studies have highlighted that splicing patterns are frequently altered in cancer and that mutations in genes encoding spliceosomal proteins, as well as mutations affecting the splicing of key cancer-associated genes, are enriched in cancer. In parallel, there is also accumulating evidence that several molecular subtypes of cancer are highly dependent on splicing function for cell survival. These findings have resulted in a growing interest in targeting splicing catalysis, splicing regulatory proteins, and/or specific key altered splicing events in the treatment of cancer. Here we present strategies that exist and that are in development to target altered dependency on the spliceosome, as well as aberrant splicing, in cancer. These include drugs to target global splicing in cancer subtypes that are preferentially dependent on wild-type splicing for survival, methods to alter post-translational modifications of splicing-regulating proteins, and strategies to modulate pathologic splicing events and protein-RNA interactions in cancer.

RNA localization: Making its way to the center stage

Cells are highly organized entities that rely on intricate addressing mechanisms to sort their constituent molecules to precise subcellular locations. These processes are crucial for cells to maintain their proper organization and carry out specialized functions in the body, consequently genetic perturbations that clog up these addressing systems can contribute to disease aetiology. The trafficking of RNA molecules represents an important layer in the control of cellular organization, a process that is both highly prevalent and for which features of the regulatory machineries have been deeply conserved evolutionarily. RNA localization is commonly driven by trans-regulatory factors, including RNA binding proteins at the core, which recognize specific cis-acting zipcode elements within the RNA transcripts. Here, we first review the functions and biological benefits of intracellular RNA trafficking, from the perspective of both coding and non-coding RNAs. Next, we discuss the molecular mechanisms that modulate this localization, emphasizing the diverse features of the cis- and trans-regulators involved, while also highlighting emerging technologies and resources that will prove instrumental in deciphering RNA targeting pathways. We then discuss recent findings that reveal how co-transcriptional regulatory mechanisms operating in the nucleus can dictate the downstream cytoplasmic localization of RNAs. Finally, we survey the growing number of human diseases in which RNA trafficking pathways are impacted, including spinal muscular atrophy, Alzheimer's disease, fragile X syndrome and myotonic dystrophy. Such examples highlight the need to further dissect RNA localization mechanisms, which could ultimately pave the way for the development of RNA-oriented diagnostic and therapeutic strategies. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.

Discovery of a Small Molecule Probe That Post-Translationally Stabilizes the Survival Motor Neuron Protein for the Treatment of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is the leading genetic cause of infant death. We previously developed a high-throughput assay that employs an SMN2-luciferase reporter allowing identification of compounds that act transcriptionally, enhance exon recognition, or stabilize the SMN protein. We describe optimization and characterization of an analog suitable for in vivo testing. Initially, we identified analog 4m that had good in vitro properties but low plasma and brain exposure in a mouse PK experiment due to short plasma stability; this was overcome by reversing the amide bond and changing the heterocycle. Thiazole 27 showed excellent in vitro properties and a promising mouse PK profile, making it suitable for in vivo testing. This series post-translationally stabilizes the SMN protein, unrelated to global proteasome or autophagy inhibition, revealing a novel therapeutic mechanism that should complement other modalities for treatment of SMA.

A qualitative study of perceptions of meaningful change in spinal muscular atrophy

BACKGROUND

This qualitative study examined how individuals with Spinal Muscular Atrophy (SMA), their caregivers, and clinicians defined meaningful change, primarily in the Type II and non-ambulant type III patient populations, associated with treatment of this condition. In addition, we explored participants' views about two measures of motor function routinely used in clinical trials for these SMA subtypes, namely the expanded version of the Hammersmith Functional Motor Scale (HFMSE) and the Upper Limb Module (ULM).

METHODS

The 123 participants (21 with SMA, 64 parents, and 11 clinicians), recruited through SMA advocacy organizations, participated in one of 16 focus groups or 37 interviews. The sessions were audio-recorded, and verbatim transcripts were analyzed using a grounded theory approach.

RESULTS

For the participants, meaningful change was relative to functional ability, and small changes in motor function could have an important impact on quality of life. Because patients and families feared progressive loss of functional ability, the participants saw maintenance of abilities as a meaningful outcome. They believed that measures of motor function covered important items, but worried that the HFMSE and ULM might not be sensitive enough to capture small changes. In addition, they felt that outcome measures should assess other important features of life with SMA, including the ability to perform daily activities, respiratory function, swallowing, fatigue, and endurance.

CONCLUSIONS

Given the heterogeneity of SMA, it is important to expand the assessment of treatment effects to a broader range of outcomes using measures sensitive enough to detect small changes.

Modulation of aberrant splicing in human RNA diseases by chemical compounds

Pre-mRNA splicing is an essential step for gene expression in higher eukaryotes. Alternative splicing contributes to diversity of the expressed proteins from the limited number of genes. Disruption of splicing regulation often results in hereditary and sporadic diseases called as 'RNA diseases'. Modulation of splicing by small chemical compounds and nucleic acids has been tried to target aberrant splicing in those diseases. Several RNA diseases and splicing-target therapeutic approaches will be briefly introduced in this review. Accumulating knowledge about molecular mechanism of aberrant splicing and their correction by chemical compounds is important not only for RNA biologists, but also for clinicians who desire therapies for those diseases.

Pharmacomodulation of microRNA Expression in Neurocognitive Diseases: Obstacles and Future Opportunities

Given the importance of microRNAs (miRNAs) in modulating brain functions and their implications in neurocognitive disorders there are currently significant efforts devoted in the field of miRNA-based therapeutics to correct and/or to treat these brain diseases. The observation that miRNA 29a/b-1 cluster, miRNA 10b and miRNA 7, for instance, are frequently deregulated in the brains of patients with neurocognitive diseases and in animal models of Alzheimer, Huntington's and Parkinson's diseases, suggest that correction of miRNA expression using agonist or antagonist miRNA oligonucleotides might be a promising approach to correct or even to cure such diseases. The encouraging results from recent clinical trials allow envisioning that pharmacological approaches based on miRNAs might, in a near future, reach the requirements for successful therapeutic outcomes and will improve the healthcare of patients with brain injuries or disorders. This review will focus on the current strategies used to modulate pharmacological function of miRNA using chemically modified oligonucleotides. We will then review the recent literature on strategies to improve nucleic acid delivery across the blood-brain barrier which remains a severe obstacle to the widespread application of miRNA therapeutics to treat brain diseases. Finally, we provide a state-of-art of current preclinical research performed in animal models for the treatment of neurocognitive disorders using miRNA as therapeutic agents and discuss future developments of miRNA therapeutics.

A future perspective on neurodegenerative diseases: nasopharyngeal and gut microbiota

Neurodegenerative diseases are considered a serious life-threatening issue regardless of age. Resulting nerve damage progressively affects important activities, such as movement, coordination, balance, breathing, speech and the functioning of vital organs. Reports on the subject have concluded that neurodegenerative disease can be caused by mutations of susceptible genes, alcohol consumption, toxins, chemicals and other unknown environmental factors. Although several diagnostic techniques can be used to determine aetiologies, the process is difficult and often fails. Research shows that nasopharyngeal and gut microbiota play important roles in brain to spinal cord coordination. However, no conclusive epidemiologic evidence is available on the roles played by respiratory and gut microbiota in the development of neurodegenerative diseases. Thus, understanding the connection between respiratory and gut microbiota and the nervous system could provide information on causal links. The present review describes future perspectives on the role played by nasopharyngeal and gut microbiota in the development of neurodegenerative diseases.

Calpain research for drug discovery: challenges and potential

Calpains are a family of proteases that were scientifically recognized earlier than proteasomes and caspases, but remain enigmatic. However, they are known to participate in a multitude of physiological and pathological processes, performing 'limited proteolysis' whereby they do not destroy but rather modulate the functions of their substrates. Calpains are therefore referred to as 'modulator proteases'. Multidisciplinary research on calpains has begun to elucidate their involvement in pathophysiological mechanisms. Therapeutic strategies targeting malfunctions of calpains have been developed, driven primarily by improvements in the specificity and bioavailability of calpain inhibitors. Here, we review the calpain superfamily and calpain-related disorders, and discuss emerging calpain-targeted therapeutic strategies.

Translocator protein (TSPO) ligands for the diagnosis or treatment of neurodegenerative diseases: a patent review (2010-2015; part 1)

INTRODUCTION

The translocator protein (TSPO) is an emerging target in diverse neurodegenerative diseases. Up-regulated TSPO in the central nervous system (CNS) appears to be involved in neuroinflammatory processes; therefore, the development of potent TSPO ligands is a promising method for alleviating or imaging patients with neurodegenerative diseases. Areas covered: This review will provide an overview of recently developed TSPO ligands patented from 2010 to 2015. Part 1 will present a summary focusing on TSPO ligands other than indole-based or cholesterol-like compounds, which will be discussed in part 2. Part 1 covers diverse benzodiazepine-derived analogues such as isoquinoline carboxamides and aryloxyanilides. Moreover, bicyclic ring structures such as imidazopyridine, pyrazolopyrimidine, and phenylpurine will be highlighted as promising scaffolds for TSPO ligands. A brief analysis of currently reported TSPO structures will also be covered in part 1. Expert opinion: Although the underlying pharmacological mechanism of TSPO remains to be elucidated, several TSPO ligands have shown therapeutic efficacy in experimental animal models of neurodegenerative diseases. In addition, radioactive TSPO ligands have been extensively studied for the diagnosis of neurodegenerative processes. Thus, further studies on both the basic and applied mechanisms of TSPO are warranted in the pursuit of successful pharmacological applications of TSPO ligands.

Morpholino-mediated Knockdown of DUX4 Toward Facioscapulohumeral Muscular Dystrophy Therapeutics

Derepression of DUX4 in skeletal muscle has emerged as a likely cause of pathology in facioscapulohumeral muscular dystrophy (FSHD). Here we report on the use of antisense phosphorodiamidate morpholino oligonucleotides to suppress DUX4 expression and function in FSHD myotubes and xenografts. The most effective was phosphorodiamidate morpholino oligonucleotide FM10, which targets the polyadenylation signal of DUX4. FM10 had no significant cell toxicity, and RNA-seq analyses of FSHD and control myotubes revealed that FM10 down-regulated many transcriptional targets of DUX4, without overt off-target effects. Electroporation of FM10 into FSHD patient muscle xenografts in mice also down-regulated DUX4 and DUX4 targets. These findings demonstrate the potential of antisense phosphorodiamidate morpholino oligonucleotides as an FSHD therapeutic option.

RNA therapeutics: RNAi and antisense mechanisms and clinical applications

RNA therapeutics refers to the use of oligonucleotides to target primarily ribonucleic acids (RNA) for therapeutic efforts or in research studies to elucidate functions of genes. Oligonucleotides are distinct from other pharmacological modalities, such as small molecules and antibodies that target mainly proteins, due to their mechanisms of action and chemical properties. Nucleic acids come in two forms: deoxyribonucleic acids (DNA) and ribonucleic acids (RNA). Although DNA is more stable, RNA offers more structural variety ranging from messenger RNA (mRNA) that codes for protein to non-coding RNAs, microRNA (miRNA), transfer RNA (tRNA), short interfering RNAs (siRNAs), ribosomal RNA (rRNA), and long-noncoding RNAs (lncRNAs). As our understanding of the wide variety of RNAs deepens, researchers have sought to target RNA since >80% of the genome is estimated to be transcribed. These transcripts include non-coding RNAs such as miRNAs and siRNAs that function in gene regulation by playing key roles in the transfer of genetic information from DNA to protein, the final product of the central dogma in biology¹. Currently there are two main approaches used to target RNA: double stranded RNA-mediated interference (RNAi) and antisense oligonucleotides (ASO). Both approaches are currently in clinical trials for targeting of RNAs involved in various diseases, such as cancer and neurodegeneration. In fact, ASOs targeting spinal muscular atrophy and amyotrophic lateral sclerosis have shown positive results in clinical trials². Advantages of ASOs include higher affinity due to the development of chemical modifications that increase affinity, selectivity while decreasing toxicity due to off-target effects. This review will highlight the major therapeutic approaches of RNA medicine currently being applied with a focus on RNAi and ASOs.

An update on RNA-targeting therapies for neuromuscular disorders

PURPOSE OF REVIEW

Antisense-mediated modulation of transcripts is a dynamic therapeutic field, especially for neuromuscular disorders.

RECENT FINDINGS

For three diseases, this approach has advanced to the clinical trial phase, that is Duchenne muscular dystrophy, spinal muscular atrophy and myotonic dystrophy. In parallel, numerous proof-of-concept studies in cell and animal models have been reported for additional neuromuscular disorders.

SUMMARY

This review discusses the most notable advances in preclinical and clinical studies in the past year. For Duchenne muscular dystrophy, spinal muscular atrophy and myotonic dystrophy trials are ongoing to assess safety and efficacy, while in parallel preclinical studies are being conducted to identify ways to improve efficiency and delivery. For other neuromuscular diseases, progress is made as well warranting future clinical trials. However, towards clinical trial readiness, it is important not only to optimize the therapy preclinically but to also develop the infrastructure that is needed to conduct trials.

Engineering Delivery Vehicles for Genome Editing

The field of genome engineering has created new possibilities for gene therapy, including improved animal models of disease, engineered cell therapies, and in vivo gene repair. The most significant challenge for the clinical translation of genome engineering is the development of safe and effective delivery vehicles. A large body of work has applied genome engineering to genetic modification in vitro, and clinical trials have begun using cells modified by genome editing. Now, promising preclinical work is beginning to apply these tools in vivo. This article summarizes the development of genome engineering platforms, including meganucleases, zinc finger nucleases, TALENs, and CRISPR/Cas9, and their flexibility for precise genetic modifications. The prospects for the development of safe and effective viral and nonviral delivery vehicles for genome editing are reviewed, and promising advances in particular therapeutic applications are discussed.

Antisense Oligonucleotide Therapy for Inherited Retinal Dystrophies

Inherited retinal dystrophies (IRDs) are an extremely heterogeneous group of genetic diseases for which currently no effective treatment strategies exist. Over the last decade, significant progress has been made utilizing gene augmentation therapy for a few genetic subtypes of IRD, although several technical challenges so far prevent a broad clinical application of this approach for other forms of IRD. Many of the mutations leading to these retinal diseases affect pre-mRNA splicing of the mutated genes . Antisense oligonucleotide (AON)-mediated splice modulation appears to be a powerful approach to correct the consequences of such mutations at the pre-mRNA level , as demonstrated by promising results in clinical trials for several inherited disorders like Duchenne muscular dystrophy, hypercholesterolemia and various types of cancer. In this mini-review, we summarize ongoing pre-clinical research on AON-based therapy for a few genetic subtypes of IRD , speculate on other potential therapeutic targets, and discuss the opportunities and challenges that lie ahead to translate splice modulation therapy for retinal disorders to the clinic.

The delivery of therapeutic oligonucleotides

The oligonucleotide therapeutics field has seen remarkable progress over the last few years with the approval of the first antisense drug and with promising developments in late stage clinical trials using siRNA or splice switching oligonucleotides. However, effective delivery of oligonucleotides to their intracellular sites of action remains a major issue. This review will describe the biological basis of oligonucleotide delivery including the nature of various tissue barriers and the mechanisms of cellular uptake and intracellular trafficking of oligonucleotides. It will then examine a variety of current approaches for enhancing the delivery of oligonucleotides. This includes molecular scale targeted ligand-oligonucleotide conjugates, lipid- and polymer-based nanoparticles, antibody conjugates and small molecules that improve oligonucleotide delivery. The merits and liabilities of these approaches will be discussed in the context of the underlying basic biology.