Category: Krabbe disease

Project financed by ELA up to: 60 000 €

Krabbe leukodystrophy (KD) is a progressive and fatal neurologic lysosomal storage disorder that usually affects infants and causes death before two to three years of age. Hematopoietic Stem Cell Therapy extends the long-term survival with improved quality of life for KD patients, but it is not a cure. Using our newly developed KD animal model, we will identify which brain cell(s) needs to be efficiently cured with therapy.

Project financed by ELA up to:  71 082 €

Globoid Cell Leukodystrophy (GLD) is a neurodegenerative lysosomal storage disease (LSD) due to the genetic deficiency of beta-galactosylceramidase (GALC). The rapid disease progression of the infantile forms and the severe neurodegeneration pose major issues for the development of effective treatments. Currently, GLD patients lack real therapeutic options.

The promising but still modest results obtained in pre-clinical models using innovative approaches (i.e. gene/cell therapies) highlight the difficulty of providing timely (before onset of symptoms), pervasive (to all affected tissues), and long-term (ideally for the whole life) therapeutically relevant levels of GALC enzyme in a safe manner. This difficulty relies in part on our imperfect understanding of the mechanisms of enzymatic correction in the different cell types that are targets (i.e brain cells) or effectors (the progeny of blood stem cells) in the context of gene/cell therapy approaches. This is a gap that we aim to fill with this study.

The long-term goal of this study is to design therapeutic approaches based on solid mechanistic ground achieved using relevant GLD models. We hypothesise that the use of a GALC enzyme engineered to increase its secretion and capability to cross the blood-brain barrier may boost the efficacy of gene/cell therapy approaches in GLD, as it does in pre-clinical models of similar diseases. Taking advantage of our expertise in the study and treatment of GLD, and building upon the availability of novel reagents and tools, we will design chimeric GALC enzymes that will be tested for secretion/bioavailablity, safety, and modality of action in direct comparison with the unmodified enzyme in relevant cells types (i.e. hematopoietic stem/progenitor cells and differentiated progeny) and, ultimately, in GLD mice.

Successful completion of this project will increase mechanistic knowledge of disease correction in GLD, paving the way to novel gene/cell therapy strategies using modified enzymes to be applied as independent treatments and/or in combination to achieve global disease correction.

Project financed by ELA up to: 95 000 €

Krabbe disease (KD, or Globoid cell leukodystrophy) is an autosomal recessive, neurodegenerative disease caused by the deficiency of the lysosomal enzyme galactocerebrosidase (GALC). It is a lethal metabolic disorder, with a frequency of about 1/100000 newborns. The early childhood form represents the 85-90% of cases and the onset of symptoms is between the 3rd and the 6th month after birth. First symptoms are dysphagia, nervousness, hypertonia; convulsions are often present as well. During the advanced state, blindness and deafness show up; then a vegetative state arises which ends with death within the first 1-2 years after birth.

Unfortunately, the systemic administration (e.g. by intravenous injections) of GALC is not effective because of the presence of the blood brain barrier (BBB) that forbids the translocation of bulky proteins like GALC into the central nervous system. No cure is currently available for KD, and treatment is symptomatic and supportive only.

Our strategy to overcome this issue is to exploit active nanoparticles capable of transporting GALC across the BBB. Thanks to a previous pilot study supported of ELA, we demonstrated that with this approach it is possible to achieve GALC activity recovery in the brain of the mouse model of KD, and in cells from KD patients.

With this project, we will perform a complete pre-clinical testing in the KD murine model. An enzyme replacement therapy (ERT) protocol will be optimized based on our nanoparticles to deliver functional GALC via systemic administration into the mouse brain. We will test if this therapy can improve the pathophysiology in terms of: i. life span, ii. prevention/slow-down of neuropathological alterations, and iii. preservation of motor functions.

Given that the materials used in this study are already approved for clinical use, in case of successful project outcome, this research has the potential for a short/medium term clinical translation. Finally, we would like to point out that our methodological approach, here proposed to correct GALC deficiency, is potentially applicable to other lysosomal storage disorders with major brain involvement, such as the Metachromatic Leukodystrophy, by changing the cargo (i.e. the functional enzyme) transported by the nanoparticles.

Project financed by ELA up to: 48 000 €

Globoid cell leukodystrophy (GLD) is a neurodegenerative inherited genetic disease, due to defects in an enzyme that normally degrades sphingolipids, a class of biological molecules present in the myelin sheath, necessary for nervous tissue function. The name of this enzyme is beta-galactosylceramidase (GALC). Impairment of GALC activity in GLD results in progressive demyelination and nerve tissue degeneration. Most individuals with infantile forms die before the age of two. Currently, there is no cure for GLD.

Several gene replacement therapy strategies have been attempted in pre-clinical models with varying degree of success, however, still facing the challenge of providing widespread enzymatic reconstitution and full correction of pathology in affected tissues, particularly the central and peripheral nervous systems (CNS and PNS). Previous evidence suggests effective transport across the blood brain barrier of several therapeutic proteins when fused with parts of other proteins, known to be able to reach CNS and PNS. Thus, GALC will be endowed with these additional portions, which may be sufficient to ensure its transport across the blood brain barrier.

In addition, we will equip GALC with small portions of highly secreted proteins to improve GALC secretion by cells. The long-term objective of the proposed research is thus to develop a safe and effective liver gene therapy for GLD. In vivo gene therapy to the liver indeed offers the attractive prospects of a minimally invasive, one-time potentially curative treatment for GLD, by providing sustained pervasive high amounts of a functional GALC enzyme to the CNS and PNS through the bloodstream.

Here we propose a project to obtain an early proof-of-principle in a mouse model of the disease. The CNS and PNS are naturally protected by a blood brain barrier that ensures selective passage of necessary substances, while blocking potentially dangerous molecules. Lentiviral vectors (LV) are attractive gene delivery vehicles for liver gene therapy thanks to their ability to insert their DNA into the host cell DNA. For this reason, LV are maintained following liver cell proliferation in liver growth and turnover, including potentially in newborns, that would be the target population in GLD. We have developed LV that allow stable expression of therapeutic proteins in the liver of mice and dogs, following systemic administration. More recently, we have generated engineered LV with increased resistance to capture by cells of the immune system, a process called phagocytosis. Thanks to this feature, these LV are more efficient at reaching the target cells in the liver.

Here we propose to generate LV expressing the above-described optimized GALC from the liver, administer them intravenously to newborn mice affected by GLD and assess survival and correction of the hallmarks of the GLD disease. We also propose to engineer LV to further escape phagocytosis by exposing on their surface additional inhibitors of phagocytosis. If successful, the work proposed here will allow the generation of novel LV with increased protection from phagocytosis and efficiency of gene transfer into liver cells that will facilitate development and manufacturing to quality and scale required for use in humans and alleviate concerns of possible LV particle dose dependent acute toxicity. These LV, transporting the engineered GALC enzymes, may become a feasible, sustainable, safe and effective liver gene therapy for GLD and potentially for other leukodystrophies.

Project financed by ELA up to: 96 000 €

This project will test a new small molecule that is designed to reduce the activity of the enzyme acid ceramidase, which is the enzyme that synthesizes psychosine. Psychosine is a lipid that accumulates to high levels in the brain of Krabbe disease, a genetic disorder caused by deficiency of another enzyme called GALC, which controls the degradation of psychosine. In the absence of GALC activity, psychosine continues to be produced but not degraded. High levels of psychosine in Krabbe disease cause neuropathology and motor and cognitive declines in infants, juvenile and adult patients. There is no cure for Krabbe disease. Here we will treat animal models of infantile and adult onset Krabbe disease with the small compound singly and in combination with a gene therapy approach to restore the activity of the enzyme GALC, which is deficient in Krabbe disease. We hypothesize that reducing the synthesis of psychosine will improve the metabolism of psychosine, reduce disease burden and neuropathology.

Project financed by ELA up to: 100 000 €