8th International Wolfram Symposium Presentation Dr Benjamin Delprat – University of Montpellier, France

8th International Wolfram Symposium Presentation Dr Benjamin Delprat – University of Montpellier, France
Advances on the pharmacological and gene therapies approaches
 
Abstract: Wolfram syndrome is a rare autosomal recessive disease affecting many organs with life-threatening consequences and currently no treatment is available. Therefore, the need to find a cure is imperative. The pathology is related to the deficient activity of wolframin, an endoplasmic reticulum (ER) transmembrane protein were shared from Estonia (Dr Mario Plaas). Final time point studied 7.5 months. Some changes detected very early (from 3 months). involved in contacts between ER and mitochondria termed mitochondria associated- ER membranes (MAMs). Inherited mutations usually reduce the protein’s stability, altering its homeostasis and ultimately reducing ER to mitochondria Ca2+ transfer resulting in mitochondrial dysfunction and cell death. We previously demonstrated that improving MAMs functioning by overexpressing NCS1, a wolframin partner, is efficient in correcting the cellular and behavioral alterations in our preclinical models of the pathology.
 
Based on these data, we focused our research on another crucial protein of the MAMs physiology, the sigma-1 receptor (S1R), an endoplasmic reticulum resident protein involved in Ca2+ transfer. Very interestingly, S1R could be activated by small active molecules to foster the Ca2+ transfer between ER and mitochondria. Therefore, we demonstrated that activation of S1R with the prototypic agonist PRE-084, restored Ca2+ transfer and mitochondrial respiration in vitro, corrected the associated increased autophagy and mitophagy, and was able to alleviate the behavioral symptoms observed in the genetic animal models of the disease, i.e. hyperlocomotion in wfs1abKO zebrafish and memory deficits and anxiety in Wfs1∆Exon8 mice. Our findings provide a new therapeutic strategy for Wolfram syndrome patients, by efficiently boosting MAM function using the ligand operated S1R chaperone.
 
Points noted:
•  NCS-1 (neuronal calcium sensor -1) represents a relevant target for treating WS.
•  Activation of S1R is beneficial in WS – (e.g. improved memory and increased Ca2+ in WS models).
•  S1R targeting is therefore relevant for WS patients.
•  NCS-1 modulators / stabilizers were not investigated.
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8th International Wolfram Symposium Presentation Karan Ahuja, Marjan Vandenabeele, Arefe Nami, Catherine Verfaillie, Lieve Moons, Lies De Groef

8th International Wolfram Symposium Presentation Karan Ahuja1, Marjan Vandenabeele2,3, Arefe Nami1, Catherine Verfaillie1, Lieve Moons2, Lies De Groef3
 
Oligodendrocytes in Wolfram syndrome: bystanders or partners in crime?
 
1Development and Regeneration Department, KU Leuven Stem Cell Institute, Leuven, Belgium 2Neural Circuit Development and Regeneration Research Group, Biology Department, KU Leuven Brain Institute, Leuven, Belgium
 3Cellular Communication and Neurodegeneration Research Group, Biology Department, KU Leuven Brain Institute, Leuven, Belgium
 
Abstract: Up till today, the neurodegenerative pathology associated with Wolfram syndrome (WS) is unstoppable. This treatment gap is at least in part due to the limited understanding of the underlying cellular mechanisms. In particular, it is becoming increasingly clear that –although neurons eventually die– there is a central role for glial cell types in most neurodegenerative disorders and it is essential to determine which of these cell types is the catalyst of the disease processes leading to WS, so that future therapies can be targeted to this cell type. In this study, based on recent evidence suggesting that the neurodegenerative component of WS could be driven by an oligodendrocyte rather than a neuronal pathology, we aimed to investigate what the effect of these ‘diseased’ oligodendrocytes is on the function of ‘healthy’ neurons, focusing on ER stress, mitochondria and cell metabolism as potential underlying mechanisms.
Our studies in iPSC-derived oligodendrocytes from WS patients reveal that these may be more vulnerable to ER stress and display signs of mitochondrial dysfunction. This, together with their seemingly reduced capacity to transfer metabolites and thereby support axons, suggests that oligodendrocyte dysfunction may, at least partially, be underlying the neurodegenerative component of WS. Next, we validated these findings in vivo, by investigating the retina and optic nerve of the Wfs1 KO mouse. We found that functional and glial cell alterations precede structural neuronal changes, and that these animals have problems with the oligodendrocyte cell lineage, leading to a decreased oligodendrocyte precursor cell number, a thinner myelin sheet and more signs of axonal degeneration in the Wfs1 KO animals. Finally, MRI studies of the brain of these Wfs1 KO mice showed a reduction in the volume of several brain regions, including the cerebellum, brainstem and corpus callosum which are also affected in WS patients– as well as changes in the apparent diffusion coefficient, pointing towards neurodegeneration and changes in myelination. Based on these data, it is tempting to speculate that the white matter changes and neuronal loss observed in WS patients is at least partly caused by problems with the supportive functions of oligodendrocytes: signal transduction via myelination and metabolic support of axons. This suggests that future WS therapies may need to target oligodendrocytes, rather than or in addition to neurons. All in all, our findings indicate that the eye is a window to the brain, with the retina reflecting the pathological processes ongoing in the brain.
 
Points noted:
•  Wfs1 KO mice
•  Also shared preliminary in vitro data where ER stress, mitochondrial dysfunction and cell death were observed in WS patient derived cell lines.
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8th International Wolfram Symposium Presentation Randal Hand PhD – Director of Neuroscience Research, Prilenia Therapeutics 

8th International Wolfram Symposium Presentation Randal Hand PhD – Director of Neuroscience Research, Prilenia Therapeutics
 
Pridopidine: A selective and potent S1R agonist as a potential treatment for Wolfram Syndrome
 

Points noted:
•  Pridopidine is currently in clinical trials for neurodegenerative conditions (e.g. ALS (Ph II moving into Ph III); Huntington’s (Ph III).
•  Currently being explored in WS due to commonalities in cellular pathways.
•  Rescue with Pridopidine has been shown to reduce ER stress and improve mitochondrial respiration in WS models.
•  Nausea and dizziness have been reported side-effects (fairly typical side- effects).
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8th International Wolfram Symposium Presentation Dr Xuehao Cui – PhD student and research fellow University of Cambridge and Moorfields Eye Hospital

8th International Wolfram Symposium Presentation Dr Xuehao Cui – PhD student and research fellow University of Cambridge and Moorfields Eye Hospital
 
Exploring novel ocular biomarkers of disease in Wolfram syndrome
 
Abstract: Visual loss in Wolfram syndrome arises primarily due to the selective loss of retinal ganglion cells resulting in optic nerve degeneration. We are exploring various ocular imaging modalities that would provide us with additional non-invasive tools to monitor this process more closely in affected individuals. Progressive brainstem and cerebellar atrophy are also well-recognised neuroradiological features of Wolfram syndrome and these could potentially be assessed by more detailed eye movement recordings. Our objective is to validate ocular biomarkers of disease in Wolfram syndrome that are both applicable to clinical practice and as outcome measures for treatment trials.
 
Points noted:
•  Aim to protect RGCs to stabilise vision / slow down vision loss.
•  Currently exploring a number of approaches to assess vision [e.g. OcuMet
(ocular mitochondrial health); Flavoprotein fluorescence (early signs of mitochondrial dysfunction) Optical Coherence Tomography (OCT; different layers of the retina); eye movement recording (level of OA)].
•  Recruiting patients (n=30) to a new study during May and June 2023; BWCH will refer patients to help boost numbers for the study.
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8th International Wolfram Symposium Presentation Prof Gil Leibowitz – President of the Israel Endocrine Society (IES), Hadassah Medical center, the Hebrew University, Jerusalem, Israel. 

8th International Wolfram Symposium Presentation Prof Gil Leibowitz – President of the Israel Endocrine Society (IES), Hadassah Medical center, the Hebrew University, Jerusalem, Israel. 

Pathophysiology and treatment of type 2 Wolfram syndrome.

Abstract: Type 2 Wolfram syndrome results from a missense mutation in the CISD2 gene, encoding NAF-1, which transfers Fe-S clusters from the mitochondria to cytosolic acceptor proteins. The carrier rate of CISD2 missense mutation among the Palestinian population in the Middle East is 1:40, suggesting a founder effect. Type1 and type 2 Wolfram syndrome have common and distinct clinical features, suggesting heterogeneity in disease phenotype and pathophysiology. NAF-1 deficiency leads to increased labile iron accumulation in the mitochondria with subsequent development of mitochondrial dysfunction and oxidative stress, resulting in neurodegeneration and diabetes. Treatment of NAF-1 deficient cells by iron chelation, N-acetylcysteine and GLP-1-RA reduced mitochondrial iron overload and alleviated oxidative stress and mitochondrial dysfunction. I will discuss the therapeutic implications of these findings. 

Points noted: 

  • T2WS is not extremely rare in the Middle east region (compared to WFS1). This is very different from the situation reported elsewhere (e.g. in US – almost all patients have WFS1 mutations rather than CISD2 mutations). 
  • CISD2 gene mutation (Glutamate – Glutamine, 8 amino acid frameshift with abnormal splicing and stop sequence) generates a protein which is 25% of the size of the native protein that is rapidly degraded. Unrelated families can carry the same mutation. 
  • Combined GLP-1-RA (e.g. exenatide) and N-acetylcysteine generate increased effects, compared with single treatment (e.g. beta cell protection). 
  • Better understanding of T2WS has implications for more common forms of Diabetes Mellitus. 
  • Early intervention is likely to be needed. 
  • RCTs need broad international collaboration. 
  • Heterozygous mutations were not studied to date. 
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Characterization of Mouse Models for Optic Atrophy in Wolfram Syndrome -Urano Lab

Characterization of Mouse Models for Optic Atrophy in Wolfram Syndrome -Urano Lab

Venu Gurram, William An, Shrini Bimal, Nila Palaniappan, Toko Campbell, Pooja Neerumalla, Devynn Hummel, Brianna Carman, Cris Brown, and Fumihiko Urano

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8th International Wolfram Symposium Presentation Dra. Gema Esteban- Bueno, Dr. Juan R. Coca, Dr. Nicolas Fernández-Fernández, Leticia Fernandez Amores, Miguel Navarro Cabrero, Dra. Aida Berenguel-Hernández and Spanish Multidisciplinary Wolfram Syndrome Group. Spain.

8th International Wolfram Symposium Presentation Dra. Gema Esteban- Bueno, Dr. Juan R. Coca, Dr. Nicolas Fernández-Fernández, Leticia Fernandez Amores, Miguel Navarro Cabrero, Dra. Aida Berenguel-Hernández and Spanish Multidisciplinary Wolfram Syndrome Group. Spain.

Descriptive analysis of 68 patients with Wolfram syndrome with emphasis on sensorineural involvement and possible phenotype-genotype correlation.

Abstract: Our work consists in providing greater knowledge of what already exists in the Wolfram Syndrome phenotype with special attention to hearing loss, through a descriptive and longitudinal study of two sets of patients affected from Spain and Portugal. The first set (descriptive study) contain a registry with patients that have been appearing since 1999, and the second set collects data from multidisciplinary assessments that have been carried out in Spain since 2011 year after year (longitudinal study).

In turn, a brief study of the genotype-phenotype relationship of the hearing loss that exists in patients of Spain and Portugal with Wolfram Syndrome has been carried out, based on the genetic data collected by our team.

Point noted:

·  Spanish and Portuguese families are evaluated through a multi-disciplinary team, who are in regular contact – to listen to families; accumulate experience and provide biopsychosocial support.

·  Currently assessing 2 patient populations (second set is a sub-set of the first).

·  No definitive pattern can be established for hearing loss or progression. Homozygous genetic changes are more severe.

·  The team actively participates in the WS Global Awareness Day and plan more activities for 2023.

·  The team are keen to collaborate with other groups / researchers to help drive change for families – valuable dataset.

·  University of Birmingham group (through Dr Renuka Dias) has been assessing gonadal function – connecting with the team in Spain may be helpful.

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8th International Wolfram Symposium Presentation Dr. Vania Broccoli – CNR – National Research Council Institute of Neuroscience, Milan. Italy

8th International Wolfram Symposium Presentation Dr. Vania Broccoli – CNR – National Research Council Institute of Neuroscience, Milan. Italy.

New function of Wolframin in regulating the monocarboxylate transporter 1 (MCT1) in glial cells in brain and retina.

Abstract: A key pathological manifestation in Wolfram syndrome is the progressive optic atrophy which leads to relentless visual loss. Although some of the pathological mechanisms caused by wolframin mutations have been unraveled in the recent years, how they impinge on visual deficits it remains unclear. Through genomics and proteomics analyses on retinal tissues isolated from wolframin mutant mice, we identified a significant reduction of the monocarboxylate transport isoform 1 (MCT1) and its partner basigin that are highly enriched on retinal glia and myelin- forming oligodendrocytes in optic nerve together with wolframin. Loss of MCT1 causes a failure in lactate transfer from glial to neuronal cell bodies and axons leading to a chronic hypometabolic state that can cause retinal ganglion cell (RGC) degeneration. This metabolic dysfunction occurs months before the frank RGC degeneration suggesting an extended time-window for intervening with new therapeutic strategies focused on boosting retinal and optic nerve bioenergetics in WS1.

Points noted:

• Retinal ganglion cells (RGCs) are vulnerable in WS, the genetic link to symptoms still needs to be understood.
• Mice WS KO model(s) were shared from Estonia (Dr Mario Plaas) – nerve damage and visual acuity loss are detected early (6-8 months) before very significant RGC loss (12 months).
• Developed working hypothesis of biochemical pathway alterations that lead to lack of energy metabolites and neuron loss.
• One future goal is to understand the structure of wolframin protein, (which is not easy!). Therefore, intend to collaborate with expert group based in New York.
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8th International Wolfram Symposium Presentation 

8th International Wolfram Symposium Presentation by Dr Malgorzata Zatyka – Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham. UK

Depletion of WFS1 compromises mitochondrial function in hiPSC-derived neuronal models of Wolfram syndrome.

Abstract: Mitochondrial dysfunction involving mitochondria-associated ER membrane (MAM) dysregulation is implicated in the pathogenesis of late-onset neurodegenerative diseases, but understanding is limited for rare early-onset conditions. Loss of the MAM resident protein WFS1 causes Wolfram syndrome (WS), a rare early-onset neurodegenerative disease that has been linked to mitochondrial abnormalities. However, contradictory reports on mitochondrial functionality in non-human or nonclinical cell models and lack of data in disease- affected settings have precluded biomedical exploitation.

Here we demonstrated mitochondrial dysfunction in human induced pluripotent stem cell-derived neuronal cells of WS patients. VDAC1 was identified to interact with WFS1, whereas loss of this interaction in WS cells could compromise mitochondrial function. Genetic rescue by WFS1 restoration or pharmacological agents modulating mitochondrial function improved the viability and bioenergetics of WS neurons. Our data implicate a role of WFS1 in regulating mitochondrial functionality and highlight a therapeutic target for WS and related rare diseases with mitochondrial defects.

Points noted:

·  Mitochondrial dysfunction and increased oxidative stress are seen in human induced PCS derived neuronal cells from WS patients.

·  Not all typical biochemical mitochondrial markers were seen in WS patient derived cells.

·  Treatment to rescue WSF1, rescued mitochondrial function and reduced cell death.

·  WSF1 interacts with VDAC1 and may regulate VDAC1 function formation.

·  Not yet assessed investigational compounds in this model to evaluate potential benefits.

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Deafblindness #6

Today ends the Deafblind Awareness Week. Deafblindness isn’t obvious and you can’t always tell by looking at someone. Try to be open and inclusive always. Hopefully we can make the world a more deafblind-friendly place. Support the Snow Foundation today in honor of those who struggle with vision and hearing loss. https://thesnowfoundation.org/donate/

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