Study into the best approach of USH1B

LEES ARTIKEL IN NEDERLANDS

Stichting Ushersyndroom (Dutch Usher Syndrome Foundation) announces with pride its financing of a study that will test the best approach for USH1B (gene) therapy by making use of, among others, patient-specific cell models and a large animal model. This may take a (gene) therapy for USH1B to the pre-clinical phase. Dr. Kerstin Nagel-Wolfrum, who works at the Johannes Gutenberg University in Mainz, will lead this project.

Children suffering from Usher Syndrome type 1 (USH1) are born deaf and with a non-functioning organ of balance (the vestibular system). The first signs of loss of eyesight, such as night-blindness and a decreasing field of vision, will present themselves later in the childhood period. USH1 is most often caused by mutations in the MYO7A gene (USH1B). About 14% of all people suffering from Usher Syndrome has type 1B. The MYO7A gene is a very large gene and the Myosin protein is also called a motor protein. Is has a ‘head and a tail’ and therefore it must be replaced or processed as a whole when developing a gene therapy.

New approaches
The large size of the MYO7A gene makes classical gene therapy using an AAV vector impossible. However, new approaches, including double and triple AAV vectors, mini-genes, prime editing, translational read-through and exon skipping, are promising new alternative therapeutic strategies. Please go to the Knowledge portal for further reading.

From skin biopsy to mini-retina
With the help of a skin biopsy from a USH1B patient (fibroblast), Dr Nagel-Wolfrum can further develop these molecular cells into a retinal pigment ephithelium (RPE) and a retinal organoid (RO). The retinal pigment epithelium is found between the retina and the choroid and it clears away the waste products of the rods and cones in the retina. The retinal organoids are also called the mini-retinas.

The possibility to model retinal disorders by means of fibroblasts into mini-retinas created unprecedented opportunities in the research area.

Dr. Kerstin-Nagel-Wolfrum

Gain insights and test therapies
By making use of the ‘mini-retinas’, Dr Kerstin Nagel-Wolfrum will gain more insight into the mechanism that damages the retina and causes loss of eyesight. Apart from this, she wants to subject these retinal organoids (mini-retinas) to various therapies in order to test them for their effectiveness and functionality. Dr Nagel-Wolfrum will also test the mini-genes by conducting an AAV vector-based gene therapy.

On to the pre-clinical phase
A large animal model, a USH1B pig, has already been developed and is ready for testing possible therapies. Dr Nagel-Wolfrum will apply the therapy that the pre-study with the retinal organoids (mini-retinas) has shown to be the most effective one when doing research on the pig model. This study is called the pre-clinical phase. If this pre-clinical phase leads to positive results, this can be promising for a possible therapy for patients.

In this project Dr Kerstin Nagel-Wolfrum closely cooperates with:

  • U. Wolfrum (Institute for Molecular Physiology, JGU Mainz, Germany): USH1B pig model
  • S. Gerber (University Medical Centre Mainz, Institute of Human Genetics, Germany): Bioinformatics
  • M. Cheetham (UCL, London, United Kingdom): iPSC-RPE and iPSC-RO generation
  • V. Kalatzis (Institute for Neurosciences of Montpellier, France): iPSC-RPE and iPSC-RO generation
  • J. Gopalakrishnan (Heinrich-Heine University Düsseldorf, Germany): brain organoids

This project will have a duration of 1 year and has been budgeted at
€ 100.000, -. Stichting Ushersyndroom hopes that this study will contribute to the development of one or more effective treatments for people suffering from Usher Syndrome type 1B.

View the PowerPoint presentation about this research by Dr. Kerstin Nagel-Wolfrum

Tears as a source of information?

LEES ARTIKEL IN HET NEDERLANDS

Stichting Ushersyndroom and Usher Syndrome Ireland

finance research into USH1b

Can tears provide information that may be important for improving diagnostics and monitoring in future treatments of USH1b patients? In the pilot study “Investigating the exosome content as a novel marker for Usher syndrome 1b” Dr. Irene Vázquez Domínguez, who is working at the Radboudumc (Nijmegen, the Netherlands), will investigate tears. By doing this, she wants to assess whether there is any indications on tears that can be employed as a source of information and therefore may contribute to not only increase the current knowledge of the disease but also to allow better prediction of the development of Usher Syndrome type 1b.

This study will be mainly financed by the Usher Syndrome Foundation and partially co-financed by Usher Syndrome Ireland. If this study produces any positive results, the study of tears may lead to new strategies in USH research.

Tears
Tears are human body fluids. Tears are rich of proteins, lipoproteins and exosomes. Exosomes are small bladders which contain a wide range of molecules inside like RNA molecules. Thanks to that, exosomes are important for the communication between cells. In addition, they can be isolated from tears, which allow the study of their content.
As tears can be collected in a non-invasive way (without entering the body) from patients, they allow for easy and patient-friendly isolation of exosomes.

New biomarker for research
Biomarkers are measurable indicators that may indicate that someone is ill, predict how serious the illness will be or show whether a treatment is effective or not.

By making use of tears, the researcher Dr. Irene Vázquez Domínguez wants to find out whether biomarkers can be found that may be used to improve the diagnostics and to better predict the development of Usher Syndrome type 1b. In the long term, point-of-care tests could be developed on the basis of these biomarkers. Point-of-care tests offer care professionals the possibility to start, monitor or adjust a future development.

The MYO7A geneWe know that more than 10 genes are involved in Usher Syndrome.
This new study is focused on one of these genes, being the MYO7A gene. This gene is responsible for the production of a specific protein: Myosin, which keeps the photoreceptors (the rods and cones) of the retina alive.

Some children having mutations in the MYO7A gene do not develop retinitis pigmentosa in their childhood and puberty beside their hereditary deafness. Here we speak of non-syndromic deafness 

How can this be explained and/or predicted? The answer to this question may lead to better diagnostics. Sometimes it is really difficult for the parents to cope with the uncertainty whether or not their child will develop retinitis pigmentosa (RP).

Increasing the present knowledge about the MYO7A gene is necessary for finding new biomarkers that can be used for making the diagnosis and for predicting the development. At the same time, this knowledge can also be used in monitoring after a treatment.

Isolation of exosomes
Usher Syndrome falls within the group of Retinal Dystrophy diseases (RDs). The deterioration of the eyesight is caused by the dying of retinal cells, such as the light-sensitive photoreceptors and/or the retinal pigment epithelium (RPE).
Within the retina RPE cells are responsible for the majority of the production of exosomes. Previous studies indicated that tears may be rich of RPE exosomes.

The goal of the study is to isolate exosomes from tears as well as from RPE cells. Then, the content of both will be studied. First, the control group will be compared with the material from USH1b patients. Then the information from tear derived exosomes and RPE derived exosomes will be also compared to assess if, as it was suggested before, they provide the same information. If this turns out to be successful, this study will show that exosomes can be used as a means to develop new strategies in USH research.
Finally, this study will also show whether tears can be a source for research. This would help to find an easy and patient-friendly way to isolate exosomes.

This one year study was budgeted at  € 75.000, -.
Stichting Ushersyndroom (Dutch Usher syndrome Foundation) will finance this study with co-financing from Usher Syndrome Ireland.

 

Watch the powerpoint presentation by
Dr. Irene Vázquez Domínguez 

New type of Usher Syndrome discovered: USH IV   

LEES ARTIKEL IN HET NEDERLANDS

The team of the Hearing & Genes Expert Centre of Radboudumc lately made a discovery: Usher Syndrome includes four different clinical types. The researchers, with Hedwig Velde as principal author, recently published their study and findings in the leading Human Genetics. With the identification of minor faults (mutations) in the ARSG gene and the description of a new clinical picture, they confirm the discovery of a fourth type of Usher Syndrome. 

This really is an important discovery, which gives more clarity about a number of patients with atypical Usher complaints without a genetic diagnosis. In the meantime, following the identification of ARSG as Usher gene, globally fifteen people have still been diagnosed, now that they all appear to have mutations in the ARSG gene. As it has been demonstrated that these patients have a common pattern of symptoms, this is no longer an atypical picture, but it makes up a new clinical type.       

A patient with an atypical clinical picture
Very rarely a patients visits the outpatients’ clinic showing symptoms that correspond with the clinical picture of Usher Syndrome (loss of hearing combined with retinitis pigmentosa), but which picture deviates from the familiar Usher types. This is called an atypical clinical picture. In some cases no generic cause is found in the Usher genes that are known so far. Consequentially, these patients are unfortunately sent home again without having been diagnosed (and without any clarity). 

Hedwig velde

 Hedwig Velde is researcher and doctoral candidate at the ENT section Hearing & Genes of the Radboudumc. She is studying patients who suffer from loss of hearing but who have not been genetically diagnosed. With her research team she confirmed a new Usher Syndrome type, which is caused by minor faults in the ARSG gene.  

A publication from the year 2018 written by a group of scientists in Israel described the discovery of the ARSG gene with Arylsulfatase G as a protein that might be involved with Usher Syndrome. The researchers from Israel described five persons from three families who all had the same minor fault in the ARSG gene. Such a publication may give other researchers ideas for their studies.  

Studying the DNA of several people within one family sharing the same symptoms is a big help for scientists. Hedwig Velde: “There is a big chance that all patients within the family share the same genetic cause. When outside the family that has been studied another patient is found with the same atypical clinical picture and a minor fault in the same gene, this may confirm the relation between the gene and the clinical picture. Of course, the chance of coming across this patient is really small. Usher Syndrome is very rare.”  

Until the national Expert Centre in the Radboud UMC saw a patient with this atypical clinical picture of Usher Syndrome and Hedwig Velde and other researchers in the Radboud UMC continued the study that was started by the team in Israel in 2018.    

New type now confirmed
With the publication of Hedwig Velde c.s. the researchers confirmed this new type. The researchers found minor faults in the same gene (the ARSG gene), which creates the codes for the Arylsulfatase G protein. This protein is involved in the degradation of another protein and the idea is that malfunctioning of Arylsulfatase G will lead to an adverse accumulation of the protein that normally should be destroyed. With this study the research team also demonstrated that the minor faults in the ARSG gene that have been found really result in a non-functioning protein.  

The clinical picture of the type does not fit in with the already known Usher types I, II and III. Apart from a later starting age of both the loss of hearing and the retinitis pigmentosa, the ophthalmic defects are more centrally located. This means that the vision problems with these patients rather occur in the central part of the field of vision as opposed to the other Usher types, which usually show problems in the outer part of the field of vision (the periphery). As the clinical picture is consistent with all USH IV patients, researchers of the Radboud UMC are of the opinion that this is not atypical Usher, but a new clinical type: Usher Syndrome type 4.   

Hedwig: “By publishing these findings, we as researchers hope to start up a discussion in the scientific world. Various studies may together lead to the confirmation that the findings are correct or, in some cases, rebut these findings. In case of USH IV it is the accumulation of evidence in several publications that enables us to confirm that this clinical type really is a new Usher type.”    

By now, globally several patients have been diagnosed for this Usher Syndrome type and for minor faults in the same ARSG gene. Previously, these patients used to be categorised in the group ‘diagnosis unknown with atypical Usher symptoms’.    

The course of Usher Syndrome type IV
Both the loss of hearing and the complaints related to retinitis pigmentosa start at a later age with people suffering from USH IV. Patients started to develop complaints concerning hardness of hearing between the ages of 20 and 40 and the retinitis pigmentosa between the ages of 40 and 60. Based on the audiograms of USH IV patients, the research team has been able to calculate that the loss of hearing starts about the age of 17.  

The course and the progressiveness are not necessarily milder than with the other Usher types. “We still have little insight into the course of USH IV, because only fifteen patients have been described and we therefore have to base our findings on this small group.” 

Genetic tests or not?
With this discovery the researchers of the Radboudumc have managed to fit in yet another piece of the ‘Usher puzzle’.” Thanks to this, a part of the patients with an unknown diagnosis will eventually be given clarity and this is really important to this group of patients.  

Unfortunately, there still are people for whom the Usher-related symptoms cannot be confirmed by a diagnosis. This makes genetic tests so important!    

The physicians indicate that, of course, the choice is still to be made by the patient. One patient attaches a lot of value to a confirmation by means of genetic tests, while another does not.  
Hedwig: “There are various reasons to have genetic tests done or not. An advantage of a genetic diagnosis is that with this the development of a disorder can better be predicted and that this may help the patient to adapt to the situation. Imagine that you are hard of hearing at a young age and that there is a small chance of becoming visually impaired. However, if you know that you will be visually impaired, then you had better concentrate on the kind of care that will help you both early and later in life. For instance, in this case learning sign language will not be a long-term solution for your loss of hearing, but good hearing aids may make a substantial contribution.”  

Genetic tests will also help the scientific world to get further. For example, as scientific research allows for comparing the DNA of various patients, new genetic causes can be discovered. Besides, this offers a possibility for meticulously mapping out the relation between a minor fault in a gene and the corresponding complaints.
Hedwig: “Because of this, future patients can be better informed about their diagnoses. On the other hand, it is also important for any future genetic treatments to know the exact underlying deviations in the DNA.”    

Usher Syndrome: 4 types and 11 genes involved
In 2022, type IV and the ARSG gene will be added to the list of Usher types and genes involved in the development of Usher Syndrome. So at this moment, Usher Syndrome distinguishes 4 types with 11 different genes involved. [Ed.: This evidence is not entirely conclusive for USH1J (CIB2) yet]
For all these genes scientific evidence has been provided that minor faults (mutations) in these genes will result in Usher Syndrome.    

The Knowledge Portal of the Usher Syndrome Foundation provides a complete overview of the genes with the names of the ‘protein involved’.     

Here you can read the publication of the article by Hedwig Velde c.s. in Human Genetics.  

 

New research: testing gene therapy

With extra large vectors on mini retinas 

Prof. Dr. Jan Wijnholds and promovendus Rossella Valenzano

Stichting Ushersyndroom [ Dutch Usher Syndrome Foundation] is funding the majority of the new research “Genetic drugs preventing blindness due to loss of USH2A function” which has recently started. The research team led by Jan Wijnholds, who works at the Leiden University Medical Center (LUMC), will test two treatment methods on ‘mini-retinas’ made from human stem cells. The researchers want to determine if the light sensitive cells in the mini-retinas can be activated by the light-sensitive cells after administration of gene therapy. Can the USH2a gene in the retina be replaced or is it also possible to repair the defective gene at the same time?

 

Gene therapy looks very promising and developments in this area are moving very quickly. It is a treatment method for hereditary disorders where healthy copies of genes, with errors (= mutations) have been found, in patients are replaced or repaired in the cells of an organ.

Research shows that after gene therapy, the retina can make normal connections with other cells, which can lead to a light response again. After delivering a healthy copy of the gene or repairing the gene, the retina makes the proteins it needs to see properly. With gene therapy you treat the entire gene so that it does not matter what kind of mutations you have.

Means of transport for the large USH2A gene
In gene therapy, a healthy copy of the gene is delivered to a specific location in the retina of the eye using a molecular truck, or a means of transport. This is usually done using a virus that has first been rendered harmless so that a vector remains, a kind of ‘packaging’. The most commonly used vector is the adeno-associated viral vector (AAV).
However, there is a problem. The USH2A gene is much too large for a normal AAV vector, so another alternative must be sought to deliver the large healthy copy of the USH2A gene into a patient’s eye.

Large trucks as vector
Previously, in collaboration with Dr Manuel A.F.V Gonçalves (Department of Chemical Cell Biology), the researchers in Jan Wijnholds’ lab at the LUMC, have developed new vectors into which very large genes fit, the so-called High-Capacity Adenoviral Vectors (HcAdV).
The large USH2A gene fits completely into this vector. As a result, this vector can serve as a molecular truck and can be used as a vector for gene therapy.

Mini retinas
In the research project “Genetic drugs preventing blindness due to USH2A function”, human mutant USH2A iPSC retinal organoids are used to test several new high-DNA capacity gene therapy vectors. These USH2A ‘organoids’ are ‘mini-retinas’ made from cell lines derived from USH2A patients.

These ‘mini-retinas’ are used because they allow to study the effect of loss of USH2A protein (Usherin) in the cilium of the photoreceptor. The cilium transports the essential proteins in the retina. These ‘organoids’, made from patient cell lines, could also be used in the future to test gene therapy for retinal disorders due to mutations in other Usher genes.

Replace gene and/or edit gene
In the research project of Jan Wijnholds, two types of gene therapy are being tested on the ‘mini retinas’. The first type of therapy candidate is an HcAdV vector containing a healthy copy of the USH2A gene that, after delivery, replaces the defective USH2A gene in the retina. We call this gene replacement therapy. The healthy copy of the gene must activate the gene in the photoreceptors of the ‘mini retinas’, the ‘organoids’.

The second type of therapy candidate is an HcAdV vector containing ‘a repair kit’ and, after delivery into the retina, repairs the defective USH2A gene in the eye itself. This is also known as gene editing therapy, CRISPR-Cas9 is used for this. CRISPR are pieces of DNA with codes that can detect the defective gene. The Cas9 is an enzyme that ‘cuts’ out the defective gene and ‘sticks’ a new healthy piece of DNA in it.

Both the CRISPR and Cas9 are transported in a cassette and delivered into the retina by an HcAdV vector. The USH2A gene is edited and repaired at its destination.

Promises for large groups of patients
Both technologies for genetherapeutic application are not dependent on the type of mutations in the USH2A gene. If the USH2A gene is found to be expressed in the light-sensitive cells of the mini-retinas thanks to one or both techniques, the treatment may become available to all patients with USH2A. When more money becomes available for research for these two techniques , the research team of Jan Wijnholds could also test these for other Usher genes, and could possibly also be a solution for patients with mutations in Usher genes other than USH2A.

The mission of Stichting Ushersyndroom
Annouk van Nunen, secretary of Stichting Ushersyndroom, is very pleased with the start of this research. Stichting Ushersyndroom’s mission is “In 2025, Usher Syndrome will be treatable!”.Annouk: “We want all patients to have a realistic prospect in 2025 of a treatment that can slow down, stop or even restore the further deterioration of their hearing and vision”.

The big challenge for scientists is to explore multiple research routes in order to eventually develop a treatment for all people with Usher syndrome. Stichting Ushersyndroom therefore stimulates as many lines of research as possible, so that people with Usher Syndrome can make their dreams come true. “It is fantastic that so much research is being done into Usher Syndrome in the Netherlands. This type of research is hopeful for all USH2A patients. But if it works, it could also be a solution for patients with mutations in other Usher genes, Annouk van Nunen.

This four-year study, which started in November, has been budgeted at € 250.000. Stichting Ushersyndroom is contributing € 85.000 to this research. Other funds that have contributed are: Rotterdamse Stichting Blindenbelangen, LSBS, Stichting Blindenhulp and a partial contribution from the LUMC Ophthalmology Departmen

Minigenes USH2A: General status

By Erwin van Wijk, lead researcher Radboudumc

Errors in the code of the USH2A gene explain the development of Usher syndrome in about 50% of all patients.
In addition to Usher syndrome, these errors can also lead to non-syndromic Retinitis Pigmentosa; loss of sight but without the hearing problems.
The USH2A gene contains the code for the protein usherin. After translation, the mistakes in the genetic code of USH2A also end up in the usherin protein, with the result that this protein loses its function and people lose their sight (and hearing). Giving patients a new copy of the USH2A gene that does not contain these errors could be an obvious solution. This is the principle of gene therapy.

However, for USH2A this is not as easy as it sounds.

New copies of genes are delivered with inactivated viruses, into which the genes are packaged. These viruses can be seen as small trucks. However, the loading platforms of the viruses are small. So small, in fact, that the USH2A gene simply doesn’t fit. Developing a classical gene therapy for USH2A is therefore extremely difficult from a technical point of view.

As an alternative, we have the “genetic patch” methodology, also known as exon skipping. The first patch tested is performed on patients tested in clinical trials.

Good news, but only for a limited target audience. QR-421a works for people with errors in a specific part of the USH2A gene: exon 13. This method can be extended to other USH2A genes and even to other Usher genes, but always remains only applicable for a limited number of patients.

Is there no alternative?

A few years ago we started with a new idea: can we not artificially shrink the USH2A gene, so that it fits in the loading platform of a virus and can therefore be delivered to the place where it is needed and can be used by all people with USH2A-related retinitis pigmentosa?

The main advantage is that, if effective, this method may be of value to all patients with USH2A-related retinal problems. The project “Minigenes USH2A” was born and made possible in part by a contribution from the Dutch Usher Syndrome Foundation (Stichting Ushersyndroom).

Four shortened USH2A genes were made and inserted into the retina of the USH2A zebrafish model. The shortened usherin proteins made from these minigenes in the zebrafish eye ended up in the right place in the light-sensitive cells of the retina, rods and cones. Functional tests by measuring electroretinograms (= ERG) indicate that these mini-usherin proteins are indeed (partially) functional. We have patented these results. How well they work remains to be investigated, but it is a promising starting point for further developing this method.

In the meantime, we are also looking into cultured cells to see where these mini-proteins go and whether they do not accumulate in a place where we would not want this. Fish, of course, are not people. It is therefore important to translate these results into models that are closer to humans.

We are currently trying to establish a partnership with a company that can help us take these important next steps.

Read also:

Swim at night and take a nap during the day

Zebrafishes suffering from USH2A have a disturbed sleep rhythm

Are patients suffering from Usher Syndrome so tired because of the huge efforts made in connection with their poor hearing and eyesight or is something else going on? Researchers in the Radboudumc try to find an answers to this question. There are indications that perhaps there is more going on, a genetic cause. The people of the Radboudumc have been busy trying to unravel Usher Syndrome for decades already. This summer, the research into ‘The recognition of sleeping problems with patients with the USH2A gene’ will start. Stichting Ushersyndroom (Dutch Usher Syndrome Foundation) will finance a large part of this study.

Researchers have used the zebrafish model since several years. In the laboratory of the Radboudumc both healthy zebrafishes and fishes suffering from Usher Syndrome are swimming about. Researchers noticed that the sleeping pattern shown by the fishes with a mutated USH2A gene differs from that of their healthy congeners. Actually, they sleep more often during the day and less often at night. According to Erwin, project leader of the zebrafish lab and engaged in research into Usher Syndrome for years already, the sleeping fishes are quite remarkable. It is day, there is sufficient light in the aquarium and the eyesight of the fishes is still good enough to be able to properly see light and dark. Still, they regularly fall asleep during the day.

Sleep-wake rhythm
The sleep-wake rhythm is strongly controlled by light. The retina sends signals to the pineal gland in the brains to make the sleeping hormone melatonin when the light intensity decreases. It is known that a decreasing light perception can disturb this system. However, RP patients regularly mention sleeping problems and fatigue in an early stage already, independent of the seriousness of their visual impairment.

Fatigue
Usher Syndrome is also called ‘fragmentary observation’: both hearing and seeing are done in small fragments that subsequently have to be made into a whole. This is hard work for the brain. Therefore it is not surprising that many people suffering from Usher Syndrome are tired quickly and have a higher chance of getting overstimulated and loosing energy. The energy-absorbing process of continuously compensating the one sense with the other leads to fatigue.

Sleep enables the body to recover, such as replenish energy sources, adjust muscles and other cells and reduce stress. While sleeping, we also process all we have seen, heard and done during the day. The brains are stimulated all day and have to process all this information.

Quality of sleep
The quality of sleep depends on the deep sleep, the so-called REM sleep. This makes the body recover. A good night’s rest means quickly falling asleep and sleeping all night through. In case of insufficient REM sleep, you do not feel refreshed well when you have to get up. Non-optimal REM sleep over a longer period will lead to chronic fatigue with a risk of other physical complaints.

Not tired at all
At the end of the day, when it begins to grow dark and the lights are switched off in the zebrafish lab, the last round is made in the lab. Many fishes have become less active already and are hanging around in the water without moving. They also do not react when Erwin van Wijk is walking along the aquariums.

When visiting the zebrafish lab in the evenings, he tries to make as little noise as possible and the lights are dimmed. When he switches off the lights to close the lab and leaves the lab, some groups of zebrafishes stay awake and active. The zebrafishes with mutations in the USH2A gene are not going to sleep, they are not yet tired at all.

Expression in the pineal gland
The most frequently mutated RP genes (USH2A and EYS) are both highly expressed in the pineal gland of various animal models. Researchers show that the proteins of these genes involved are not only present in large quantities in the eyes and ears, but in the pineal gland as well. This may mean that the proteins concerned also play an important role in the pineal gland and in the regulation of the day and night rhythm.

Zebrafishes with mutations in the USH2A gene show a deviating sleep-wake rhythm, while these test animals hardly show any retina degeneration.
Based on these findings researchers suspect that the sleeping problems of these groups of patients are the cause of the disorder and not just the consequence of a reduced visual function.

Comprehend
A treatment for sleep-related complaints with people who have mutations in the USH2A and EYS genes, may substantially improve their quality of life. In this project clinical and fundamental research are combined in order to comprehend these problems. The common results of these two research lines may give some tools to improve the care of patients suffering from RP and Usher Syndrome together with ophthalmologists and sleep experts.

Various research institutes are involved in this project: the Radboudumc under the leadership of Erwin van Wijk, Slaap/Waakcentrum SEIN, Hospital Gelderse Vallei, Radboud University and the Donders Institute.

This four-year study will start this summer and the costs are estimated to be € 285.000,=.  Stichting Ushersyndroom (Dutch Usher Syndrome Foundation) makes a contribution of € 125.000 with co-financing by the Dutch Dr. Vaillantfonds. Other funds that have contributed are: LSBS, ANVVB, Support Fund UitZicht (Beheer ’t Schild), the Gelderse Blindenstichting, FNWI/IWWR.

Onderzoekers en patiënten met Ushersyndroom overhandigen een cheuq ter warde van €285.000 voor het slaaponderzoek. Ze staan voor de kast met aquaria met zebravissen.

In the zebrafish lab Radboudumc. From left to right: Erik de Vrieze, Thijs Bouwman, Niels Bouwman, Ivonne Bressers. Jessie Hendricks, Devran Braam, Erwin van Wijk and Juriaan Metz.

Stichting Ushersyndroom [Dutch Usher Syndrome Foundation] Awards Grant to Usher III Initiative to Support Patient Database

A global Usher III patient (USH3) database for future clinical trials

This year, the North-American foundation Usher III Initiative has taken preliminary steps towards collecting the information necessary to establish the first comprehensive global USH3 patient database. This resource will be critical to the design of future clinical trials and will significantly advance knowledge of the disease and its impact on patients. Dr Ronald Pennings from the Radboudumc is one of several physicians and experts around the world collaborating with the Initiative in this effort. 

Cindy Elden and her father Richard, co-founders of the Usher III Initiative

Usher III Initiative
Usher III Initiative is a US based non-profit organization dedicated to developing a treatment for Usher Syndrome type 3 a rare genetic disorder characterized by progressive loss of both hearing and vision. It is estimated that over 400.000 people around the world suffer from Usher Syndrome, of which type 1 and 2 are the most common types. Only 2 percent of the patient population suffers from USH3, which is most prevalent among Finnish and Ashkenazi Jewish populations. 

Preliminary clinical trial design
The Initiative has developed BF844, a new therapeutic candidate for the treatment of USH3.
The Initiative is completing pre-clinical toxicity studies to demonstrate that BF844 can be safely administered in humans in compliance with US Food and Drug Administration (FDA) regulations. They expect that clinical trials will commence in 2022. These studies are supported by a $1M grant the Initiative recently received from the Foundation Fighting Blindness.

Consortium
Together with the Usher III Initiative and a global consortium of physicians, Dr Ronald Pennings will participate in the establishment of the USH III Patient Database. “Aggregating comprehensive genetic and  clinical data on USH3 patients is necessary to determine inclusion and eligibility criteria as well as the most effective design for clinical trials.”, commented Cindy Elden, President and Co-Founder of the Initiative and an USH3 patient.

Collaboration
Stichting Ushersyndroom [Dutch Usher Syndrome Foundation] has committed to making a $ 10,000 contribution to support this effort. This grant aligns with the mission of the Stichting Ushersyndroom, to find treatments for all types of Usher syndrome.  

“Usher Syndrome is a serious disorder, which has a deep impact on the lives of patients and their social environments.  We want to stop this disorder from the bottom of our hearts”, commented Ivonne Bressers, chairwoman and co-founder of the Stichting Ushersyndroom and USH2 patient. “We are happy to be able to participate in an international study for USH3-patients.”

Cindy Elden: “On behalf of the Usher III initiative, but also personally, I find it very inspiring to meet other people with Usher syndrome who would like to be active in the search for a treatment for all of us!”

The consortium will not be collecting any information that identifies specific patients, so the database cannot be used to recruit participants for clinical trials. Patients interested in participating in future clinical trials are encouraged to register with My Retina Tracker and the Ush Trust. Once trial investigators and sites have been identified, treating physicians may also recommend individual patients to the appropriate officials. Pursuant to global patient privacy protections, the Usher III Initiative cannot receive confidential patient data. If patients, family or friends want to connect with the Usher III Initiative for more information, they are invited to email info@usheriii.org or connect on Facebook.
Dutch patients can contact Stichting Ushersyndroom for more information on Usher syndrome and contact with fellow sufferers.
For medical advice on Usher syndrome, information on (preclinical) developments of therapeutic approaches to treat Usher syndrome or additional (genetic) diagnostics, they can reach out to the expertise center of the Radboudumc via ushersyndroom@radboudumc.nl. 

Related links:
www.usheriii.org
www.radboudumc.nl/expertisecentrum/ushersyndroom
www.ushersyndrome.nl
www.ushersyndrome.nl/knowledgeportal

Jack Weeda, draagt een bril en witte doktersjas

A view on the RUSH2a study

In the international RUSH2a study of Jacque Duncan MD, University of California, San Francisco, 120 patients spread over nine different clinics are monitored for four years. This study includes only syndromic (USH2a) and non-syndromic patients with mutations in the USH2a gene (nsRP).

The study “Rate of progression of USHer Syndrome” is done at about 20 clinical centres around the world, including the Radboudmc in Nijmegen, the Netherlands and is financed by the Foundation Fighting Blindness. Researcher Jack Weeda is working as a research optometrist in the Radboudumc on the RUSH2a study. He takes us with him in his work and gives us a view of the study.

The RUSH2a study and the CRUSH study
Recently, we already could read about the current state of affairs of the CRUSH study. Read here.
Also thanks to the Medical Advisory Council of the Stichting Ushersyndroom, the content of the CRUSH study has been aligned to RUSH2a study. This means that the research questions and the study measurements are largely similar, allowing the results of RUSH2a study to be compared with those of the CRUSH study. This comparison of the results is of scientific value.

The differences between both studies are mainly in the working area of the ENT department. For instance, the CRUSH study includes more audiological research and a one-off balance test is done. This study is conducted under the leadership of Dr Ronald Pennings. The RUSH2a study includes a one-off smelling test. The RUSH2a is conducted under the leadership of Dr Carel Hoyng. 40 patients are participating in the CRUSH study, while the RUSH2a study has about 120 international participants, nine of which are Dutch.

Here read about the similarities and the differences between the RUSH2a and the CRUSH studies.

Jack Weeda, draagt een bril en witte doktersjas

Jack Weeda, research optometrist at the Radboudumc Nijmegen, the Netherlands

Curious patients group
Jack Weeda is research optometrist at the ophthalmology department of the Radboudumc in Nijmegen. Since 2012 he has mainly worked for all scientific studies done at the department through the Trial centre of Prof Hoyng. In 2018, Jack Weeda took up the coordination of the RUSH2a study and a year later the ophthalmology part of the CRUSH study as well. In the past few years, Jack Weeda has seen about 60 Ushers and he still sees many of them on an annual basis.

 

Jack Weeda: “By now, I have got to know the patients group as a curious, positively critical, well-organised and really active patients group. I regularly see participants of the study I know appear in various ways in the media and thanks to one participant I almost even made my first appearance on television.”

The first results
The RUSH2a study started about a year before the start of the CRUSH study and by now the first results appear. For instance, an article was recently published about the ophthalmological and otological differences between people suffering from Usher Syndrome and people suffering from autosomal recessive RP (AR-RP) or non-syndromic RP (nsRP). Patients suffering from AR-RP do have mutations in the USH2a gene, but there is no or hardly any loss of hearing. The first findings have shown that patients with Usher Syndrome have more severe loss of field of vision than patients with nsRP do. Read more: https://pubmed.ncbi.nlm.nih.gov/32446738/

From the RUSH2a study an article was published about the FST study, a relatively new study that is conducted in the CRUSH and RUSH2a studies. In this FST study light flashes in three colours, being red, blue and white, are offered and of each colour it is determined which intensity of the flash is just perceived. The values resulting from this study appear to be a good indicator of the seriousness and the duration of retinitis pigmentosa. Possibly, these values can also be used to measure the effectiveness of any future therapy, but this needs further research. For the researchers it is interesting to see whether comparable results can be measured using the data from the CRUSH study. The researchers will soon start working on this. Read this article: https://pubmed.ncbi.nlm.nih.gov/33133772/

Jack Weeda hopes that together with the participating patients he will be able to make more minor and perhaps even major discoveries in both studies and in this way further solve the Usher mystery.

How are things going with the ‘minigenes USH2c’ study?

By now, the USH2c minigenes study was started almost a year ago. A four-year study which was made possible by co-financing of the Stichting Ushersyndroom, CUREUsher and LSBS. Thanks to many contributors this study was started early in the year 2020 in the research group of Erwin van Wijk, in the Radboudumc. Merel Stemerdink is working as a doctoral candidate on the development of a minigene therapy for USH2c. In this news report, Merel tells more about the progress that she has been able to make with respect to the study during the past year! 

Merel in the aquarium holding the tank in which the USH2c zebrafishes are swimming.

The minigenes
USH2c is caused by mutations in the USH2c gene (ADGRV1) and these faults in the gene result in progressive hereditary deafblindness. In the eye these faults make the retina slowly die. The objective of the project is to develop a minigene therapy specifically for treating this retina degeneration. 

What makes the development of a therapy a challenge is that the ADGRV1 gene is really big, so big that it cannot be packed in the ‘lorry’ (‘viral vector) that is to deliver a new, healthy copy of the gene at the correct place in the retina. This is the reason why we are making an artificial short version of the ADGRV1 gene. These minigenes will be small enough to fit in a ‘viral vector’, but at the same time the minigenes have to function well enough to make good the negative effect of the mutations in the ADGRV1 gene. 

Based on various bioinformatics analyses we have developed four ADGRV1 minigenes. These minigenes contain the most important pieces of the healthy ADGRV1 gene. In the past year, we managed to isolate all these individual pieces of ADGRV1 and I will start assembling these parts and so eventually make the minigenes in the coming months. However, this obviously is not all: after this we will study whether these minigenes are actually able to take over the function of the mutant ADGRV1 gene.  

Zebrafishes with USH2c
In order to test the therapeutic effect of minigenes, we made an USH2c zebrafish last year. Zebrafishes also have the ADGRV1 gene and we see with healthy zebrafishes that ADGRV1 is expressed in the retina, just as with humans. By means of CRISPR/Cas-9 technology, we deliberately made small faults in the ADGRV1 gene of zebrafishes so as to simulate the disease in the fish. Last month was really exciting, as we started the first experiments to see of the faults made in the gene really prevent the ADGRV1 protein from being produced in the eyes of the USH2c zebrafishes and this appeared to be the case indeed! In the coming year, we will do additional research in order to get a complete picture of the visual function of this USH2c zebrafish. This is important because this will be the basis of the testing of the minigenes in the USH2c zebrafishes so as to allow us to see if and to what extent the minigenes are able to recover the functioning of the retina. 

This means that the first important steps were taken in the past year: the minigenes have been developed and the first results indicate that we have developed a zebrafish model suitable for testing the minigenes! 

Do you have any questions about the study further to this news report? You can contact Merel via the mail.

 Also read:
Development of gene therapy for large USH2c gene

Positive results of QR-421a Phase 1/2 Clinical Trial for Usher Syndrome and non-syndromic Retinitis Pigmentosa

 

ProQR has published positive results from its Phase 1/2 Stellar trial of QR-421a, an investigational RNA therapy for the treatment of Usher syndrome and retinitis pigmentosa (RP) due to mutation(s) in exon 13 of the USH2A gene.

Stellar study
The Stellar study is a first-in-human clinical trial of the medicine QR-421a. The Phase 1/2 study includes adults that experience different levels of vision loss due to mutation(s) in exon 13 of the USH2A gene. This trial aims to study the safetly profile and efficacy of QR-421a.

QR-421a is an investigational RNA therapy designed to skip exon 13 in the RNA with the aim to stop vision loss.

A total of 20 clinical trial participants took part in the Stellar study. The trial design consisted of four study groups of which three groups received QR-421a at three different dose levels. A fourth group received sham treatment, where an intravitreal injection is mimicked but no injection or study drug is given. For each participant one eye was treated with a single injection of QR-421a or sham, and the fellow untreated eye was a control.

Summary

  • QR-421a was observed to be well tolerated with no serious adverse events reported.
  • QR-421a also demonstrated benefit in multiple measures of vision, including best corrected visual activity (BCVA), static perimetry, and retinal imaging (OCT).

Next steps
Based on the safety profile and early evidence of efficacy observed to date, ProQR plans to conduct two final stage/pivotal Phase 2/3 clinical trials.

The two-final stage/pivotal Phase 2/3 clinical trials, named: Sirius and Celeste, will study two different patient populations.
The Sirius study is a Phase 2/3 trial that will focus on advanced clinical trial participants with BCVA of equal or worse than 20/40. The preliminary design for Sirius is a doublemasked, randomized, controlled, 24-month, multiple-dose study.
In parallel to Sirius, the Celeste study is a Phase 2/3 trial focusing on early-moderate clinical trial participants with BCVA of better than 20/40. The preliminary design for Celeste is a double-masked, randomized, controlled, 24-month, multiple-dose study.

Read more about the results of the Stellar study here.

This study is based on the research and findings of Dr. Erwin van Wijk at the Radboudumc

Read also: Leiden ProQR is further expanding Radboudumc research