Regulation of the autophagic PI3KC3 complex by laforin/malin E3-ubiquitin ligase, two proteins involved in Lafora disease.

LaFora progressive myoclonus epilepsy is a rare neurodegenerative disorder characterized by the accumulation fatal dissolve abnormal glycogen deposits in the brain and peripheral tissues

. Mutations in at least two genes responsible for this disease: EPM2A, encoding laforin glucan phosphatase, and EPM2B, coding RING type E3-ubiquitin ligase master. Both laforin and malin form a functional complex where laforin recruit the substrate to ubiquitinated by the master. We and others have pointed out that, in cellular and animal models of the disease, there are disorders of autophagy that leads to the accumulation of dysfunctional mitochondria.

In addition, we determined that autophagic defect occurs in the early steps autophagosome formation. In this work, we provide evidence that the cellular models of disease there is a decrease in the number of phosphatidylinositol-3P. This may be due to defective regulation of autophagic PI3KC3 complex, in the absence of a functional laforin / master complex. In fact, we showed that laforin that / master complex physically interacts and co-localizes intracellularly to the core components of the complex PI3KC3 (Beclin1, Vps34 and Vps15), and that this interaction is specific and results in polyubiquitination this protein.

Additionally, laforin / malin complex is also capable polyubiquitinate ATG14L and UVRAG. Finally, we show that overexpression of laforin / complex increases the activity of master PI3KC3. These results demonstrate the new role of laforin / master complex in the activation of autophagy through regulation PI3KC3 complex and describes a defect in autophagy described in LaFora disease.
LaFora disease (LD) is a fatal epilepsy in children caused by a recessive mutation or gene either in EPM2A EPM2B.

A hallmark of LD is the accumulation of soluble polysaccharide intracellular deposits known as LaFora body (LBS) in the brain and other tissues. In the mouse model LD, genetic reduction of glycogen synthesis and rescue elimination LB formation neurological phenotype. Therefore, LBS has become a therapeutic target for ameliorating LD. Here, we show that human pancreatic α-amylase degradation of LBS. We amylase fused to an antibody fragment penetrates cells, and these antibody-enzyme fusion (VAL-0417) LBS degradation in vitro and dramatically reduce the burden of LB in vivo in Epm2a – / – mice.

 Regulation of the autophagic PI3KC3 complex by laforin/malin E3-ubiquitin ligase, two proteins involved in Lafora disease.
Regulation of the autophagic PI3KC3 complex by laforin/malin E3-ubiquitin ligase, two proteins involved in Lafora disease.

Delivery of the central nervous system and analysis of the biodistribution of the antibody-enzyme Fusion for Treatment of Diseases LaFora.

LaFora disease (LD) is a fatal epileptic teenager characterized by the accumulation of aberrant aggregates called LaFora body glucan (LBS). Protein-based therapeutic delivery to the central nervous system (CNS) for cleaning LBS remains a unique challenge in the field.

More recently, a humanized antigen binding fragment (hFab) derived from murine systemic lupus erythematosus DNA autoantibodies (3E10) has been shown to mediate cell penetration and is proposed as a carrier widely applicable to mediate cellular targeting and uptake. We report a study of the efficacy and CNS delivery of VAL-0417, the antibody-enzyme fusion consists of 3E10 hFab and human pancreatic α-amylase, in a mouse model of LD. Enzyme-linked immunosorbent assay was developed to detect VAL-0417 post-treatment as a measure of success of the post.

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We showed robust and sensitive detection of the fusion protein in several types of tissue. By using this method, we measure biodistribution in a different method of delivery. We found that the intracerebroventricular administration provided strong CNS delivery when compared with intrathecal administration. These data define the essential steps in the translation pipeline VAL-0417 for the treatment of LD.