Category: Adrenoleukodystrophy (ALD)

Florian Eichler, M.D., Christine Duncan, M.D., Patricia L. Musolino, M.D., Ph.D., Paul J. Orchard, M.D., Satiro De Oliveira, M.D., Adrian J. Thrasher, M.D., Myriam Armant, Ph.D., Colleen Dansereau, M.S.N., R.N., Troy C. Lund, M.D., Weston P. Miller, M.D., Gerald V. Raymond, M.D., Raman Sankar, M.D., Ami J. Shah, M.D., Caroline Sevin, M.D., Ph.D., H. Bobby Gaspar, M.D., Paul Gissen, M.D., Hernan Amartino, M.D., Drago Bratkovic, M.D., Nicholas J.C. Smith, M.D., Asif M. Paker, M.D., Esther Shamir, M.P.H., Tara O’Meara, B.S., David Davidson, M.D., Patrick Aubourg, M.D., et David A. Williams, M.D.– 2017

X-linked adrenoleukodystrophy (ALD) is the most common leukodystrophy. All ALD patients have a mutation in ABCD1 and accumulate very long-chain fatty acid (VLCFA) in tissues, including brain and spinal cord. In adulthood, virtually all males and >80% of women develop chronically progressive myelopathy (adrenomyeloneuropathy) for which no disease-modifying therapy is available. Hematopoietic stem cell transplantation (HSCT) and ex vivo autologous gene therapy are effective in treating cerebral ALD, but only in the early stages of brain inflammation. Unfortunately, HSCT-treated patients can still develop myelopathy in adulthood, because HSCT is only effective at halting the inflammatory component of the disease without addressing the underlying biochemical defect. This therapeutic gap highlights the need to develop effective treatments aimed at the normalization of VLCFA levels in the brain and spinal cord. Using skin cells from ALD patients we have demonstrated that saturated VLCFA induce cellular stress, with prolonged exposure resulting in cell death. This effect is not observed with mono-unsaturated VLCFA. We identified small-molecules that activate an alternative metabolic route that converts saturated to mono-unsaturated VLCFA.

Treatment of ALD cells completely corrects VLCFA levels. Treatment of the ALD mouse with these molecules added to their food results in a reduction in adrenals, spinal cord and brain. Unfortunately, are these small molecules not specific enough and cause side-effects. We are currently searching for more specific small-molecules. When found, these small-molecules must be tested in an ALD disease model. In this project we will develop a novel ALD disease model.

We already generated stem cells from control and ALD skin cells. These stem cells can be used to generate organoids, which is a miniaturized and simplified version of an organ. Interestingly, with the proper tools we can use these stem cells to generate brain organoids.

The availability of control and ALD brain organoids would be a major step forwards in the development of a therapy for ALD and other leukodystrophies. Organoids will lead to a reduction in animal studies and they are a preclinical model that better reflects the disease.

Project financed by ELA up to: 89 345 €

Adrenomyeloneuropathy is a debilitating lifelong disorder that currently has not treatments available. As an inherited disorder, gene correction is clearly necessary to alter the trajectory of disease burden. We have a developed an approach to deliver a healthy copy of the faulty gene directly into brain and spinal cord.

We have tested this in mice with the disease and have made key insights into a cell type critical to this process: neurons in the brain and alongside the spinal cord. With this knowledge we are now improving gene delivery using new viral vectors.

Importantly we have also developed industry partnerships that can help with manufacturing and setting up future clinical trials. Beyond creating a much-needed treatment, we are also through our studies gaining a better understanding of the disease biology of adrenomyeloneuropathy.

Project financed by ELA up to: 92 300 €

The adult onset autosomal dominant leukodystrophy or ADLD, is a genetic, fatal and incurable neurodegenerative disease. It is characterized by a loss of the so-called “white matter” of the central nervous system and is manifested by movement disorders and severe alterations of the autonomic nervous system.

The genetic cause is the presence of three copies, instead of the two normally present, of the gene that contains the instructions to produce the lamin B1 (LMNB1) protein, which belongs to a group of structural proteins (lamins) forming the nuclear membrane of the cell. In patients, Lamin B1 accumulates into the cells causing the neurodegeneration.

Through our project, we will provide the first therapeutic option for ADLD, developing a technique called “allele-specific silencing”. By using small molecules of RNA called “siRNAs”, we will be able to “turn off” one of the three copies of the gene, restoring the physiological lamin B1 levels, and in turn avoiding the accumulation of the protein and the disease.

To validate our therapeutic strategy mediated by siRNAs, we will generate two innovative in vitro models based on induced pluripotent stem cells (iPSC) derived from ADLD patients that will allow an authentic “disease-in-a-dish” approach. The iPSCs are a highly versatile tool, since they can be used to recreate in the laboratory different types of cells normally difficult or impossible to obtain from a patient, such as those of the central nervous system. In these models we will test genetic products already developed in our lab to measure efficacy and potency on LMNB1 reduction and the absence of negative or dangerous effects. Our project is intended to pave the way towards a therapy for ADLD and also establish distinctive human ADLD-relevant models and therapeutic approaches that may have great importance for future studies non only on ADLD but also on the physiopathology and therapy of other leukodystrophies and genetic diseases.

Project financed by ELA up to: 100 000 €

With a combined incidence of 1:14,700, X-ALD is the most common monogenetically inherited leukodystrophy. The disease is caused by mutations of the peroxisomal very long-chain fatty acid transporter ABCD1 that normally imports very long-chain fatty acids into the peroxisome for degradation. Accordingly, loss of ABCD1 function results in accumulation of very long-chain fatty acids in the plasma and body fluids of affected patients. X-ALD shows a striking phenotypic heterogeneity with inflammatory cerebral X-ALD (CALD) being the most severe form. In order to be treatable by bone marrow transplantation or gene therapy, CALD has to be recognized in its earliest stages.

The ultimate goal of this research project is to identify an easily accessible blood biomarker indicative for onset and progression of CALD. If successful, the identified blood biomarker could provide valuable information for decisions on clinical interventions and could also be used as treatment efficacy marker in clinical trials targeting CALD.

Project financed by ELA up to: 29 000 €

X-linked adrenoleukodystrophy (ALD) is the most common leukodystrophy. All ALD patients have a mutation in the ABCD1 gene that leads to a build-up of saturated very long-chain fatty acid (VLCFA) in tissues, including adrenal glands, spinal cord and brain. ALD is characterized by a striking and unpredictable clinical spectrum, even within families. In childhood, around 50% of affected boys develop adrenal disease before the age of 10 and 30-35% of affected boys develop a fatal inflammatory brain disease (cerebral ALD). If ALD is diagnosed in an early stage, cerebral ALD can be halted or reversed by a bone-marrow transplant. In adulthood, virtually all males and >80% of women develop a chronically slow progressive spinal cord disease (myeloneuropathy) for which no disease modifying therapy is available. Unfortunately, transplanted boys can still develop spinal cord disease in adulthood, because the transplant is only effective at halting the inflammatory component of the disease without addressing the underlying biochemical defect. This therapeutic gap highlights the need to develop effective treatments aimed at the normalization of VLCFA levels in the brain and spinal cord.

Using skin cells from ALD patients we have demonstrated that saturated VLCFA induce cellular stress, with prolonged exposure resulting in cell death. Remarkably, this is not observed with mono-unsaturated VLCFA (fatty acids with a double bond in the fatty acid chain). The enzyme stearoyl-CoA desaturase-1 (SCD1) coverts saturated fatty acids into mono-unsaturated fatty acids. In a previous ELA supported project we identified and characterized the drug TO901317 (an LXR agonist) as a small-molecule that activates SCD1 activity. Treatment of ALD cells with TO901317 completely corrects VLCFA levels and treatment of the ALD mouse with TO901317 added to the food resulted in a reduction in VLCFA levels in adrenals, spinal cord and brain.

Unfortunately, TO901317 (and other LXR agonists) as potential treatment for ALD have notable limitations due to off-target effects that result in serious side effects. This is largely due to LXR agonists not being specific for SCD1. We therefore hypothesize that specifically increasing SCD1 activity will circumvent the detrimental effect of LXR activation and offer a therapeutic strategy to counteract VLCFA-induced lipotoxicity in ALD.

Strategies to specifically increase SCD1, either pharmacologically or genetically have not been reported to date. Therefore, the overall goal of the proposal is to identify genetic and pharmacological regulators of SCD1 abundance and/or activity. Specifically, in this project we aim to:

• Generate cell lines in which the SCD1 enzyme is tagged with a fluorescent protein to allow monitoring of SCD1 in

1. live cells at a single cell resolution.

• Map enzymes that control SCD1 abundance using a genome-wide CRISPR/Cas9 genetic screen.
• Identify small molecules that increase SCD1 abundance and activity. Addressing these aims will increase our basic understanding of VLCFA metabolism in ALD.

Moreover, results from these experiments have the potential to inform on novel therapeutic strategies to treat ALD patients.

Project financed by ELA up to: 97 045 €