Deciphering the causes of mitochondrial network disruption in WDR45-defective cells and their contribution to the BPAN pathology

Awardee: Fulvio Reggiori

Institution: University Medical Center Groningen (UMCG)

Award Amount: $71,471

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Four researchers (Mario Mauthe, Fulvio Reggiori, Muriel Mari and Lara Barazzuol) at the University Medical Center Groningen obtained a grant from the 2020 Million Dollar Bike Ride Grant Program. The project is entitled “Deciphering the causes of mitochondrial network disruption in WDR45-defective cells and their contribution to the BPAN pathology”.

ß-propeller protein-associated neurodegeneration (BPAN) is a rare condition belonging to a group of neurological disorders collectively known as neurodegeneration with brain iron accumulation (NBIA). BPAN is caused by mutations in the WDR45 gene. While WDR45 appears to be involved in autophagy, the precise molecular function and contribution of this protein to this pathway remains unclear. Thus, although the genetic cause of the disease is known, the cellular alterations leading to the clinical manifestations in patients are still unknown.

This project aims at deciphering the underlying pathological causes of BPAN pathophysiology that are connected to autophagy but also investigating autophagy-independent causes, in particular a defect in the mitochondria network organization that we and others, have observed. This project will benefit of an ongoing collaboration between the awarded groups, Prof. Marina De Koning-Tijssen and the Dutch NBIA foundation (Stichting IJzersterk).

Neurocognitive Outcomes and Quality of Life in Adults with MSUD

Awardee: Jessica Gold

Institution: Children's Hospital of Philadelphia

Award Amount: $54,465

Funding Period: February 1, 2021 - January 31, 2022

Tissue inflammation in Mucopolysaccharidoses type II disease: molecular mechanism and therapy

Awardee: Manoj Pandey

Institution: Cincinnati Children's Hospital Medical Center

Award Amount: $64,485

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Due to iduronate 2-sulfatase enzyme deficiency, excess tissue accumulation of glycosaminoglycans (GAGs) lead to the chronic tissue inflammation in Mucopolysaccharidoses type II (MPSII) patients. The mechanisms underlying GAGs-mediated chronic tissue inflammation is remain elusive. Our preliminary data identified GAGs-induced complement activation as one of the main driver of immune inflammation that sparks tissue inflammation in MPSII. Proposed studies will now test if targeting complement activation directly in MPSII-mouse model and human cells could stop and/or slowdown the tissue inflammation. Additionally, complement activation at several steps and/or their signature cytokines could recognize as a novel biomarker for human MPSII.

Role of the GM-CSF Pathway in Heterotopic Ossification Associated with Fibrodysplasia Ossificans Progressiva (FOP) and Novel Therapeutic Strategies to Suppress the Inflammatory Response

Awardee: Eileen M. Shore

Institution: University of Pennsylvania School of Medicine

Award Amount: $40,000

Funding Period: February 1, 2021 - January 31, 2022

Influence of microbiota on innate immune responses and heterotopic ossification in fibrodysplasia ossificans progressiva (FOP)

Awardee: Daniel Perrien

Institution: Emory University

Award Amount: $40,000

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Fibrodysplasia ossificans progressiva (FOP) is a currently untreatable genetic disease in which skeletal muscle repair is misdirected to endochondral bone formation (heterotopic ossification, HO) causing pain, muscle destruction, and joint fusion, leading to progressive immobilization and eventually premature death.  Despite the monogenetic cause of FOP (gain-of-function point mutations in ACVR1/ALK2), disease severity and progression vary widely among patients with the same mutation, suggesting additional factors such as background genetics, environmental, or nutritional influences can modify the course of disease. Exciting preliminary data demonstrate that ablation of the gut bacteria (microbiota) in FOP mice reduces injury induced EHO. This project will determine whether introduction of specific anti-inflammatory bacteria to the gut microbiota can regulate the severity of injury-induced flares in FOP mice. Unlike commercially available supplements, the probiotics in these studies will include highly potent live bacteria specifically selected for their newly discovered roles in regulating musculoskeletal diseases.  If our hypothesis is proven correct, these studies may form the foundation for a clinical trial in FOP patients and multiple applications for NIH funding.

JAK1/2 as a Central Regulator of iMCD Pathogenesis and Novel Therapeutic Target

Awardee: David Fajgenbaum

Institution: University of Pennsylvania

Award Amount: $64,590

Funding Period: February 1, 2021 - January 31, 2022

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Summary: Idiopathic multicentric Castleman disease (iMCD) is a poorly understood disease involving life-threatening immune hyperactivation and cytokine production (a cytokine storm). About 1500 patients of all ages are diagnosed in the US each year and there is a 35% 5-year mortality rate. Siltuximab, which inhibits a key cytokine involved in the immune hyperactivation in iMCD, is the only FDA-approved therapy and is effective in one-third of patients. Dr. Fajgenbaum’s lab in the Center for Cytokine Storm Treatment and Laboratory (CSTL) recently identified another key mechanism of immune hyperactivation in iMCD called JAK/STAT that may be a promising target to direct treatments at. Through the Orphan Disease Center's grant, the CSTL is studying JAK/STAT in iMCD lymph node samples and the role of JAK inhibition as an iMCD treatment.  If promising, the CSTL will develop a protocol for a proof-of-concept clinical trial of a JAK inhibitor (ruxolitinib) in iMCD patients. These studies will improve understanding of iMCD biology and may translate into more effective therapies.

Conquer from Within – Treating APBD by viral delivery of cross-correction-enabled amylase

Awardee: Felix Nitschke

Institution: University of Texas Southwestern Medical Center

Award Amount: $121,268

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Adult polyglucosan body disease (APBD), an adult-onset variant of GSD IV, presents as a progressive neurological disorder involving the central and peripheral nervous system. APBD is caused by recessive mutations in the glycogen branching enzyme gene (GBE1), and the consequent accumulation of poorly branched cytosolic glycogen aggregates called polyglucosan bodies (PBs) in the nervous system. There are presently no treatments for APBD, but attenuation of PB accumulation in the APBD mouse model by genetically interfering with glycogen synthesis leads to alleviation of disease symptoms. A treatment aiming at PB removal can, therefore, prevent worsening of and potentially reverse disease symptoms. Secreted AMY2A (amylase) fused to an antibody fragment clearly digests PBs in vitro, and, by continuous delivery to the CNS it drastically reduced PBs in brains of Lafora disease mice. This protein therapy requires continuous or repeat administration. We propose to vectorize the above construct and thereby design a single-dose AAV9 viral vector that delivers cross-correction-enabled amylase. Cross-correction greatly increases efficacy of gene therapy for soluble lysosomal CNS diseases. Fab-AMY2A is inherently set up for cytosolic cross-correction by containing a specific secretion signal and the Fab fragment conferring cell-penetration. We expect to clear the CNS of PBs and to identify the most efficacious delivery route in APBD model mice. Also, we will study the progression of PB accumulation and neuroinflammation. This will allow a better definition of the therapeutic window in future studies, aiming PB removal for alleviation of neuroinflammation and prevention APBD-related changes is behavior, gait and life expectancy. 

Dissecting the Genetic and Genomic Basis of Neuroendocrine Cell Hyperplasia of Infancy (NEHI)

Awardee: Xin Sun

Institution: The Regents of the Univ. of Calif., U.C. San Diego

Award Amount: $103,066

Funding Period: February 1, 2021 - January 31, 2022

Efficacy of rapamycin and sodium phenylbutyrate in a xenograft model of IBM

Awardee: Thomas Lloyd

Institution: Johns Hopkins University

Award Amount: $68,245

Funding Period: February 1, 2021 - January 31, 2022

Deciphering variants of unknown significance in Niemann Pick Type C

Awardee: Evgueni Ivakine

Institution: Hospital for Sick Children

Award Amount: $47,630

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

As we enter an age where we understand more about genetic disease, we are beginning to regularly implement genome sequencing and personalized medicine in clinical practice. These efforts are hampered by a lack of knowledge about how mutations contribute to disease. This is particularly the case for diseases like Niemann-Pick disease type C (NPC), a rare genetic disease in which most patients present with a mutation that has not previously been reported. This leads to lengthy wait times between presentation and definitive diagnosis, as specialized laboratories are required to biochemically diagnose each potential patient. Through our work, we aim demonstrate a new method to quickly and easily create every possible mutation in each DNA base in a critical region of the the NPC1 gene using next-generation CRISPR-based gene editing technologies. Once we have generated a group of these mutant cells, we will perform a functional test to rapidly ascertain if each would likely lead to developing the disease or not. After identifying disease-causing mutations, we will apply a drug, currently undergoing clinical trials for NPC, to further classify the disease-causing mutations as responders or non-responders to this treatment.

Identification of GLUT1 Activating Compounds in a Mouse Model

Awardee: Jason Park

Institution: University of Texas Southwestern Medical Center

Award Amount: $64,200

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Glucose transporter type I deficiency (G1D) is an epilepsy syndrome that results from a mutation in the SLC2A1 gene. In normal brain function, the SLC2A1 gene makes a protein (glucose transporter type I, GLUT1) that moves glucose across the blood-brain barrier. In G1D, there is a defect in the SLC2A1 gene that results in a protein that cannot move enough glucose across the blood-brain barrier; this results in carbon deprivation of the brain and, often, seizures and other disabilities. The Million Dollar Bike Ride has funded a pilot grant to Dr. Jason Park in the Department of Pathology and the Eugene McDermott Center for Human Growth at UT Southwestern Medical Center in a study for the “Identification of GLUT1 Activating Compounds in a Mouse Model”.

Beginning in 2021, this one-year grant will fund the identification of drugs which increase the availability and/or functional activity of GLUT1. This project is in collaboration with UT Southwestern faculty member, Dr. Juan Pascual. Previously, we performed high-throughput screening of 10,000 compounds to identify GLUT1 activators in a cancer cell line model. In this project we will identify the subset of activating compounds which improve the phenotype (behavior) in G1D mice. This animal study will identify GLUT1 activating drugs for future preclinical and clinical investigation. For many years, UT Southwestern Medical Center has been at the forefront of patient care, diagnostic testing, clinical trials, patient registry, laboratory research and medical and scientific training focused on G1D. 

Understanding the effects of Sirolimus/Zolendronic acid treatment on bone remodeling activity in patients with Gorham-Stout disease

Awardee: Andrea Del Fattore

Institution: Bambino Gesù Children’s Hospital

Award Amount: $81,965

Funding Period: February 1, 2021 - January 31, 2022

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Gorham-Stout disease (GSD) is a rare bone disorder characterized by angiomatous proliferation and progressive bone loss, resulting in the appearance of the so-called “vanishing bone” disease. In our previous study, we characterized the cellular alterations leading to the perturbation of physiological bone remodeling. Indeed, we identified in GSD patients increased ability of osteoclast precursors to differentiate into mature cells and alteration of immune cells. This study seeks to characterize the effects of the treatment with mammalian target of rapamycin (mTOR) inhibitor Sirolimus and bisphosphonate Zolendronic acid on the players of remodeling process, investigating the precursors of bone resorbing osteoclasts and the immune cells.

Sirolimus is known to inhibit lymphangiogenesis and is thought to act on lymphatic tissue within lesions regulating production and leakage of lymph. Furthermore, Sirolimus influences immune cells. Bisphosphonates inhibit osteoclast bone erosion and also exert anti-angiogenic effect. Since Sirolimus and bisphosphonates may have an additive effect, GSD patients were treated with the Sirolimus and Zolendronic acid with the aim to stop the disease progression, inhibiting angiogenesis and osteoclast activity, and stimulating immune cells.

This proposal will be important to monitor the efficacy of the treatment and to identify potential prognostic markers, with the aim to translate the results into a better care of GSD patients.

Osteoclasts and pain in Fibrous Dysplasia: investigating and targeting the molecular links in a transgenic mouse model (EF1α-GsαR201C mice) of human Fibrous Dysplasia

Awardee: Mara Riminucci

Institution: Sapienza University of Rome

Award Amount: $66,263

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Osteoclasts are involved in the development and progression of Fibrous Dysplasia of bone (FD). Osteoclasts are skeletal cells that continuously resorb small amount of bone in a tightly regulated way and their function is necessary to allow the growth of the skeleton and its renewal. In FD lesions, osteoclasts remove bone in an uncontrolled manner and interfere with the deposition of normal mineralized bone, thus causing bone fragility. However, osteoclasts formation may not be blocked for long time in the entire skeleton. Using bone biopsies from FD patients and our mouse model of the disease, we previously identified some factors that could stimulate the abnormal formation of osteoclasts within FD lesions and other factors that could mediate their negative effects on bone formation. Therefore, in this project, we will attempt to block these factors in our FD mice in order to eliminate osteoclasts and/or their effects specifically in affected bones. Furthermore, we will start to investigate bone pain associated with the disease in the same mouse model. In particular we will investigate its mechanisms and its changes during the progression of the disease and during the proposed treatments.

Platforms for the identification and validation of candidate small molecule treatments for TBCK Syndrome

Awardee: Jay Vivian

Institution: University of Kansas Medical Center

Award Amount: $50,600

Funding Period: February 1, 2021 - January 31, 2022

Discovering genetic modifiers of STXBP1 protein stability

Awardee: Jimmy L. Holder, Jr.

Institution: Baylor College of Medicine

Award Amount: $71,658

Funding Period: February 1, 2021 - January 31, 2022

Circuit mechanism of STXPB1-encephalopathy interrogated using human brain organoids

Awardee: Christopher Makinson

Institution: Columbia University

Award Amount: $71,658

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Mutations in the gene STXBP1 are associated with multiple diseases ranging from intellectual disability to severe epilepsy and developmental delay. To understand how STXBP1 mutations impair brain development we will generate 3D cellular structures derived from patient cells, called brain organoids, that resemble in many ways the developing human brain. Since previous studies have shown that STXBP1 is important for chemical signaling between brain cells, we will examine how STXBP1 mutations affect excitatory and inhibitory chemical signaling within brain organoids. We will also apply novel high throughput approaches to measure the activity of many brain cells at one time in order to gain insights into the effects of STXBP1 mutations on cellular network activity. These approaches will allow us to determine if STXBP1 deficiency has more pronounced effects on certain parts of the brain. Importantly, we will leverage these approaches to look at multiple time points to clarify how impairments evolve throughout early development and contribute to disease. Support from this pilot grant will allow us to establish a novel human cell model of STXBP1 encephalopathy, develop novel approaches to measure cellular activity in human brain organoids, and facilitate efforts to develop novel treatments for STXBP1 encephalopathy.

Pharmacologic modulation of the polyamine metabolic pathway to restore normal spermidine/spermine ratios and ameliorate symptoms in Snyder-Robinson Syndrome models

Awardee: Robert Casero

Co-PI: Tracy Murray Stewart

Institution: Johns Hopkins University

Award Amount: $68,840

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Snyder-Robinson syndrome (SRS) is caused by mutation of the spermine synthase (SMS) gene that reduces the enzyme activity responsible for converting spermidine to spermine in the polyamine biosynthesis pathway. Cells of patients affected by SRS have very low levels of spermine, while spermidine levels are excessive, resulting in elevated spermidine/spermine ratios that tend to correlate with severity of disease. SRS symptoms commonly include intellectual disability, osteoporosis, low muscle mass, and seizures. There is no cure or treatment for SRS beyond symptom management. The goal of our research is to pharmacologically exploit inherent cellular polyamine control mechanisms to redistribute spermidine and spermine levels to more normal ratios. We have identified an established therapeutic with FDA-approval for other indications that has the potential to rebalance these abnormal polyamine pools in cell lines derived from SRS patients. This drug is orally bioavailable and has a proven safety record in human clinical trials, including those in children. Mechanistically, this drug is effective in reducing the biosynthesis of spermidine as well as stimulating the conversion of spermidine to spermine in patient cell lines with hypomorphic SMS activity. With the exception of a single patient, all others identified to date exhibit partial rather than complete loss of SMS function. Our continuing studies include elucidation of the specific mechanism-of-action of this drug in SRS patient cells, the potential for combination therapies with our previously described spermine mimetic, and investigation of the safety and efficacy of the drug in an SRS mouse model. By reducing the spermidine/spermine ratio observed in SRS patients, it is possible that syndrome-associated symptoms may be ameliorated.  Therefore, this agent, as a monotherapy and in combination, holds promise for not only alleviating symptoms of SRS, but doing so through targeting the underlying mechanism of the disease.

Final Report Lay Summary:

Snyder-Robinson Syndrome (SRS) is an X-linked disability syndrome that primarily affects males and manifests as a range of debilitating pathologies including osteoporosis, hypotonia, seizures, cognitive impairment, and developmental delay. Symptom severity is variable among patients and appears to correlate with the degree of increase in the SPD/SPM ratio, reflecting the reduction in SMS activity caused by the specific mutation. According to the Snyder-Robinson Foundation, approximately 80 individuals have now been identified with SRS worldwide, a number likely to increase with expanded awareness and sequencing accessibility. There is currently no treatment or cure for SRS beyond symptom management, generaly including prevention of seizures and osteoporosis progression. The Casero/Murray Stewart laboratory first reported functional polyamine transport in SRS patient ce ls, a discovery that clarified early misconceptions and revealed potential treatment strategies using polyamine-related agents, the research focus of this award. Our preliminary and published studies resulting from this award indicate the potential to rebalance polyamine pools using these agents, including DFMO, in SRS patient ce ls and animals. These results represent the first potential treatment strategy aimed at correcting the fundamental biochemical cause of SRS.

Reinstatement of Tcf4 function to treat Pitt-Hopkins Syndrome

Awardee: Andrew Kennedy

Institution: Bates College

Award Amount: $71,643

Funding Period: February 1, 2021 - January 31, 2022

Characterization of Telomere Maintenance in Tumor Models of Dyskeratosis Congenita

Awardee: Judy Wong

Institution: University of British Columbia

Award Amount: $66,440

Funding Period: February 1, 2021 - January 31, 2022

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Summary:

Work in my laboratory and others had shown that telomere maintenance defects in the bone marrow failure syndrome dyskeratosis congenita (DC) contributed to an increased risk of developing cancers. Our long-term collaboration with the Inherited Bone Marrow Failure Syndrome (IBFMS) clinical group at the National Cancer Institute provided us with the opportunity to model and study the cancer development process in DC.  Using primary patient materials collected by the IBFMS group, my laboratory will develop DC cancer models in the laboratory and study how these DC tumors overcome the innate genetic restrictions on telomere maintenance and achieve immortal growth.  The long term goal of this project is to provide new screening paradigm and to stratify treatment options for DC tumors, an unmet clinical need in the battles against the spectrum of disorders associated with this Bone Marrow Failure Syndrome.

Final Report Lay Summary:

Dyskeratosis congenita (DC) was the first telomere maintenance disorder identified in humans. DC is an inherited disease of bone-marrow failure, with symptoms that include hematopoietic, epithelial and mucosal epithelial dysfunctions. In addition, DC patients have an increased risk of developing cancers from epithelial origin, believed to be a direct consequence of accelerated telomere attrition. With advancement in the clinical management of DC mortality due to hematopoietic system failure, DC patients are now faced with an estimated hundreds-fold increase in their risk of developing cancer, with HPV-negative Head and Neck Cancer (predominantly at the tongue) being the most prominent cancer type (Haematologica, 2018). My laboratory has ongoing interests in modeling the cancer development process in DC, using primary patient materials collected from the NIH National Cancer Institute’s Inherited Bone Marrow Failure Syndrome cohort study. With funding from the UPennMDBR award, we have optimized the sequential viral infection protocol for the delivery of oncogenic elements, and successfully created four X-DC tumor models and two corresponding controls. Currently, we are conducting mouse xenograft studies using these cell models to further characterize the in vivo behavior of these XDC tumors. Our project successfully optimized the in vitro transformation protocol and established viable DC tumor models for future research towards informed patient screening guidelines and the development for novel, targeted therapeutics.

Pharmacological induction of autophagy to treat CHM

Awardee: Ivan Conte

Institution: University of Naples Federico II

Award Amount: $64,990

Funding Period: February 1, 2021 - January 31, 2022

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Final Report Lay Summary:

The main goal of this project was to characterize at fine scale the contribution of molecular network regulating the autophagy pathway in the Retinal Pigment Epithelial ce ls. We demonstrated that impairment of ce l clearance in the RPE may affect visual system in the Choroideremia. Interestingly, we put the basis for developing a new therapeutic strategy to treat CHM, which stil represents a cha lenge, Remarkably, the therapy described herein was safe and wel tolerated showing no adverse effects associated with pharmacological treatment up to 3 months of treatment, the longest time for which the drug was tested on CHM mice. Lately, in vitro studies using hiPSC-derived RPE ce l sheet give us the opportunity to move forward with regulatory studies prerequisite to clinical trials for choroideremia patients.