Muscle-specific, liver-detargeted adeno-associated virus gene therapy rescues Pompe phenotype in adult and neonate Gaa-/- mice

Pompe disease (PD) is a neuromuscular disorder caused by acid α-glucosidase (GAA) deficiency. Reduced GAA activity leads to pathological glycogen accumulation in cardiac and skeletal muscles responsible for severe heart impairment, respiratory defects, and muscle weakness. Enzyme replacement therapy with recombinant human GAA (rhGAA) is the standard-of-care treatment for PD, however, its efficacy is limited due to poor uptake in muscle and the development of an immune response. Multiple clinical trials are ongoing in PD with adeno-associated virus (AAV) vectors based on liver- and muscle-targeting. Current gene therapy approaches are limited by liver proliferation, poor muscle targeting, and the potential immune response to the hGAA transgene. To generate a treatment tailored to infantile-onset PD, we took advantage of a novel AAV capsid able to increase skeletal muscle targeting compared to AAV9 while reducing liver overload. When combined with a liver-muscle tandem promoter (LiMP), and despite the extensive liver-detargeting, this vector had a limited immune response to the hGAA transgene. This combination of capsid and promoter with improved muscle expression and specificity allowed for glycogen clearance in cardiac and skeletal muscles of Gaa-/- adult mice. In neonate Gaa-/- , complete rescue of glycogen content and muscle strength was observed 6 months after AAV vector injection. Our work highlights the importance of residual liver expression to control the immune response toward a potentially immunogenic transgene expressed in muscle. In conclusion, the demonstration of the efficacy of a muscle-specific AAV capsid-promoter combination for the full rescue of PD manifestation in both neonate and adult Gaa-/- provides a potential therapeutic avenue for the infantile-onset form of this devastating disease.

All-in-Fiber Electrochemical Sensing

Electrochemical sensors have found a wide range of applications in analytical chemistry thanks to the advent of high-throughput printing technologies. However, these techniques are usually limited to two-dimensional (2D) geometry with relatively large minimal feature sizes. Here, we report on the scalable fabrication of monolithically integrated electrochemical devices with novel and customizable fiber-based architectures. The multimaterial thermal drawing technique is employed to co-process polymer composites and metallic glass into uniform electroactive and pseudoreference electrodes embedded in an insulating polymer cladding fiber. To demonstrate the versatility of the process, we tailor the fiber microstructure to two configurations: a small-footprint fiber tip sensor and a high-surface-area capillary cell. We demonstrate the performance of our devices using cyclic voltammetry and chronoamperometry for the direct detection and quantification of paracetamol, a common anesthetic drug. Finally, we showcase a fully portable pipet-based analyzer using low-power electronics and an "electrochemical pipet tip" for direct sampling and analysis of microliter-range volumes. Our approach paves the way toward novel materials and architectures for efficient electrochemical sensing to be deployed in existing and novel personal care and surgical configurations.

Lewy Body Dementia Association's Industry Advisory Council: proceedings of the second annual meeting

In 2019, the Lewy Body Dementia Association formed an Industry Advisory Council to bring together a collaborative group of stakeholders with the goal of accelerating clinical research into Lewy body dementia treatments. At the second annual meeting of the Industry Advisory Council, held virtually on June 18, 2020, the key members presented ongoing and planned efforts toward the council’s goals. The meeting also featured a discussion about the effects of the COVID-19 pandemic on Lewy body dementia clinical research, lessons learned from that experience, and how those lessons can be applied to the design and conduct of future clinical trials. This report provides a brief summary of the meeting proceedings with a focus on efforts to improve and adapt future Lewy body dementia clinical research.

Clinical correlations and long-term follow-up in 100 patients with sarcoglycanopathies

BACKGROUND AND PURPOSE

To describe a large series of patients with α, β, and γ sarcoglycanopathies (LGMD-R3, R4, and R5) and study phenotypic correlations and disease progression.

METHODS

A multicentric retrospective study in four centers in the Paris area collecting neuromuscular, respiratory, cardiac, histologic, and genetic data. The primary outcome of progression was age of loss of ambulation (LoA); disease severity was established according to LoA before or after 18 years of age. Time-to-event analysis was performed.

RESULTS

One hundred patients (54 γ-SG; 41 α-SG; 5 β-SG) from 80 families were included. The γ-SG patients had earlier disease onset than α-SG patients (5.5 vs. 8 years; p = 0.022) and β-SG patients (24.4 years). Axial muscle weakness and joint contractures were frequent and exercise intolerance was observed. At mean follow-up of 22.9 years, 65.3% of patients were wheelchair-bound (66.7% α-SG, 67.3% γ-SG, 40% β-SG). Dilated cardiomyopathy occurred in all sarcoglycanopathy subtypes, especially in γ-SG patients (p = 0.01). Thirty patients were ventilated and six died. Absent sarcoglycan protein expression on muscle biopsy and younger age at onset were associated with earlier time to LoA (p = 0.021 and p = 0.002). Age at onset was an independent predictor of both severity and time to LoA (p = 0.0004 and p = 0.009). The α-SG patients showed genetic heterogeneity, whereas >90% of γ-SG patients carried the homozygous c.525delT frameshift variant. Five new mutations were identified.

CONCLUSIONS

This large multicentric series delineates the clinical spectrum of patients with sarcoglycanopathies. Age at disease onset is an independent predictor of severity of disease and LoA, and should be taken into account in future clinical trials.

Diagnostic anoctamin-5 protein defect in patients with ANO5-mutated muscular dystrophy

AIMS

Previously, detection of ANO5 protein has been complicated by unspecific antibodies, most of which have not identified the correct protein. The aims of the study were to specify ANO5 protein expression in human skeletal muscle, and to investigate if the ANO5 protein levels are affected by different ANO5 mutations in anoctaminopathy patients.

METHODS

Four different antibodies were tested for ANO5 specificity. A sample preparation method compatible with membrane proteins, combined with tissue fractionation was used to determine ANO5 expression in cell cultures expressing ANO5, in normal muscles and eight patient biopsies with six different ANO5 mutations in homozygous or compound heterozygous states, and in other dystrophies.

RESULTS

Only one specific monoclonal N-terminal ANO5 antibody was efficient in detecting the protein, showing that ANO5 is expressed as a single 107 kD polypeptide in human skeletal muscle. The truncating mutations c.191dupA and c.1261C>T were found to abolish ANO5 expression, whereas the studied point mutations had variable effects; however, all the ANO5 mutations resulted in clearly reduced ANO5 expression in the patient muscle membrane fraction. Attempts to detect ANO5 using immunohistochemistry were not yet successful.

CONCLUSIONS

The data presented here indicate that the ANO5 protein expression is decreased in ANO5-mutated muscular dystrophy and that most of the non-truncating pathogenic ANO5 mutations likely destabilize the protein and cause its degradation. The method described here allows direct analysis of human ANO5 protein, which can be used in diagnostics, for evaluating the pathogenicity of the potentially harmful ANO5 variants of uncertain significance.