2016 Grant Award Recipients
Thanks to the generous support of friends and family of Glut1 Deficiency patients, the Glut1 Deficiency Foundation recently awarded over $150,000 in research grant awards. We are deeply grateful to all who support the work of the Foundation and make these awards possible, and we are equally appreciative of the dedicated scientists who are interested in helping our community and improve the quality of life for Glut1 Deficiency patients.
Read more about each of the recipients and their projects below. This recent award brings the G1D Foundation’s total research giving to over $400,000 since its beginning in 2011. Funding new and innovative research is an important component of the Foundation’s mission of education, awareness, advocacy, and supporting researchers who are working for better understanding, better treatments, and ultimately a cure.
Read more about each of the recipients and their projects below. This recent award brings the G1D Foundation’s total research giving to over $400,000 since its beginning in 2011. Funding new and innovative research is an important component of the Foundation’s mission of education, awareness, advocacy, and supporting researchers who are working for better understanding, better treatments, and ultimately a cure.
Modeling Glucose Transport Across the Human Neurovascular Unit Using a Patient Derived Stem Cell Model
Abraham Al-Ahmad, PhD
Assistant Professor
School of Pharmacy Department of Pharmaceutical Sciences
Texas Tech University HSC
Amarillo, Texas
Award Amount: $14,500
thank you message from Dr. Al-Ahmad
Dr. Al-Ahmad's published paper from his research results
The blood-brain barrier (BBB) constitutes a blood-brain physical and chemical barrier restricting the diffusion of molecules and cells between the blood and the brain tissue. The entrance of nutrients (glucose, amino-acids, ions….) inside the brain tissue is tightly regulated by the presence of transporters expressed at the surface of brain microvascular endothelial cells (BMECs) lining the brain vasculature. Glucose constitutes the main source of energy for the brain function, as we estimate about 25% of daily dietary glucose consumption is routed for the brain. Glucose uptake at the BBB is considered driven only by one transporter: GLUT1 (although some studies have described the presence of other glucose transporters at the BBB, however their contribution in glucose transport at the BBB remains unclear). GLUT1 deficiency (G1D) is a neurological disorder characterized by an impaired glucose uptake at the BBB due to mutation in the GLUT1 transporter. Although it is accepted that mutations in GLUT1 impairs glucose transport at the BBB, we don’t have any studies that investigated how different mutations impact GLUT1 enzymatic activity or how other glucose transporters at the BBB may partially compensate it. In order to understand how G1D impact glucose uptake and its metabolism in the brain, we need to have a model that can help us understand such mechanisms at the cellular and molecular level. Current in vitro (cells grown on Petri dishes) models of the human BBB are not good enough to measure changes in glucose transport whereas in vivo (animal-based) models are too complex to address such questions.
Recently, patient-derived stem cells (iPSCs) have gained attention from the scientific community. Unlike embryonic stem cells, iPSCs are obtained from differentiated somatic cells (e.g. skin cells) and reprogrammed into a “stem cell-like” stage, allowing them to continuously grow and be differentiated into any type of cells. In particular, iPSCs have been recently used to model neurological diseases in a dish, including some form of childhood form of epilepsy (Dravet Syndrome). We hypothesize that developing a similar approach for modeling G1D in a Petri Dish may help us identify new targets and therapies to treat G1D patients. However, we have first to demonstrate that such an iPSC-based model is a relevant tool. In this research proposal, we propose to validate an iPSC-based model of the BBB using iPSCs obtained from “control” patients, such iPSCs being distributed through the Coriell Institute of Medical Research repository.
In our first aim, we will quantify the expression of several glucose transporters (GLUT1, GLUT3, GLUT4, SGLT1, SGLT6) that have been in the literature as being expressed in BMECs, astrocytes and neurons. We will firstly identify their expression at mRNA levels and confirm their expression as proteins. This will help map which of these transporters are expressed in our iPSC-derived model and also link it to the existing literature.
In our second aim, we want to demonstrate that our model is capable to assess glucose transport across the BBB. Because glucose transporters are facilitated transporters selective for glucose, we have to firstly demonstrate that glucose diffuse much faster than similar molecules (e.g. mannitol). Next, we have to demonstrate that glucose diffusion is saturable (by using different glucose concentrations, we can show such phenomenon). Finally, we have to demonstrate how GLUT1 blockade using selective drugs impact glucose transport across the BBB.
Once validated, this model can greatly help us to understand how genetic mutations in GLUT1 impact glucose transport and also opens the possibility to develop an in vitro model to better understand how G1D impact the function of astrocytes and neurons in G1D patients.
Abraham Al-Ahmad, PhD
Assistant Professor
School of Pharmacy Department of Pharmaceutical Sciences
Texas Tech University HSC
Amarillo, Texas
Award Amount: $14,500
thank you message from Dr. Al-Ahmad
Dr. Al-Ahmad's published paper from his research results
The blood-brain barrier (BBB) constitutes a blood-brain physical and chemical barrier restricting the diffusion of molecules and cells between the blood and the brain tissue. The entrance of nutrients (glucose, amino-acids, ions….) inside the brain tissue is tightly regulated by the presence of transporters expressed at the surface of brain microvascular endothelial cells (BMECs) lining the brain vasculature. Glucose constitutes the main source of energy for the brain function, as we estimate about 25% of daily dietary glucose consumption is routed for the brain. Glucose uptake at the BBB is considered driven only by one transporter: GLUT1 (although some studies have described the presence of other glucose transporters at the BBB, however their contribution in glucose transport at the BBB remains unclear). GLUT1 deficiency (G1D) is a neurological disorder characterized by an impaired glucose uptake at the BBB due to mutation in the GLUT1 transporter. Although it is accepted that mutations in GLUT1 impairs glucose transport at the BBB, we don’t have any studies that investigated how different mutations impact GLUT1 enzymatic activity or how other glucose transporters at the BBB may partially compensate it. In order to understand how G1D impact glucose uptake and its metabolism in the brain, we need to have a model that can help us understand such mechanisms at the cellular and molecular level. Current in vitro (cells grown on Petri dishes) models of the human BBB are not good enough to measure changes in glucose transport whereas in vivo (animal-based) models are too complex to address such questions.
Recently, patient-derived stem cells (iPSCs) have gained attention from the scientific community. Unlike embryonic stem cells, iPSCs are obtained from differentiated somatic cells (e.g. skin cells) and reprogrammed into a “stem cell-like” stage, allowing them to continuously grow and be differentiated into any type of cells. In particular, iPSCs have been recently used to model neurological diseases in a dish, including some form of childhood form of epilepsy (Dravet Syndrome). We hypothesize that developing a similar approach for modeling G1D in a Petri Dish may help us identify new targets and therapies to treat G1D patients. However, we have first to demonstrate that such an iPSC-based model is a relevant tool. In this research proposal, we propose to validate an iPSC-based model of the BBB using iPSCs obtained from “control” patients, such iPSCs being distributed through the Coriell Institute of Medical Research repository.
In our first aim, we will quantify the expression of several glucose transporters (GLUT1, GLUT3, GLUT4, SGLT1, SGLT6) that have been in the literature as being expressed in BMECs, astrocytes and neurons. We will firstly identify their expression at mRNA levels and confirm their expression as proteins. This will help map which of these transporters are expressed in our iPSC-derived model and also link it to the existing literature.
In our second aim, we want to demonstrate that our model is capable to assess glucose transport across the BBB. Because glucose transporters are facilitated transporters selective for glucose, we have to firstly demonstrate that glucose diffuse much faster than similar molecules (e.g. mannitol). Next, we have to demonstrate that glucose diffusion is saturable (by using different glucose concentrations, we can show such phenomenon). Finally, we have to demonstrate how GLUT1 blockade using selective drugs impact glucose transport across the BBB.
Once validated, this model can greatly help us to understand how genetic mutations in GLUT1 impact glucose transport and also opens the possibility to develop an in vitro model to better understand how G1D impact the function of astrocytes and neurons in G1D patients.
Testing the Efficacy of Ketone Supplementation in Glucose Transporter Type 1 Deficiency Syndrome (GLUT1 DS) Mice
Dominic D’Agostino, PhD
Associate Professor
Department of Molecular Pharmacology and Physiology
University of South Florida
Morsani College of Medicine
Tampa, Florida
Award Amount: $30,000 with ongoing support for mouse colony maintenance
Nutritional ketosis is well established as a neuroprotective metabolic therapy. Ketone bodies beta-hydroxybutyrate and acetoacetate provide an alternative fuel that helps protect the brain during limited glucose availability. Nutritional ketosis has profound anti-seizure properties in multiple animal models. Ketone supplementation can circumvent the dietary restriction that often limits the compliance and therapeutic efficacy of the ketogenic diet. The development and testing of ketone supplementation has tremendous therapeutic potential for those with GLUT1 DS.
Our laboratory continues to assess the efficacy and safety of ketone supplementation with the goal of getting this therapy to patients as fast as possible.
1) Establish and maintain GLUT1 DS mouse breeding colony at USF Vivarium (Completed with active IACUC protocol).
2) Assess behavioral and histological effects of ketone esters (BHB and AcAc) on mouse model of GLUT1 DS (Ongoing).
3) Assess behavioral and histological effects of ketone mineral salts on mouse model of GLUT1 DS (Ongoing).
4) Dose response and combined ketone formulation studies.
5) Biochemical and histological analysis of blood and tissues.
Dominic D’Agostino, PhD
Associate Professor
Department of Molecular Pharmacology and Physiology
University of South Florida
Morsani College of Medicine
Tampa, Florida
Award Amount: $30,000 with ongoing support for mouse colony maintenance
Nutritional ketosis is well established as a neuroprotective metabolic therapy. Ketone bodies beta-hydroxybutyrate and acetoacetate provide an alternative fuel that helps protect the brain during limited glucose availability. Nutritional ketosis has profound anti-seizure properties in multiple animal models. Ketone supplementation can circumvent the dietary restriction that often limits the compliance and therapeutic efficacy of the ketogenic diet. The development and testing of ketone supplementation has tremendous therapeutic potential for those with GLUT1 DS.
Our laboratory continues to assess the efficacy and safety of ketone supplementation with the goal of getting this therapy to patients as fast as possible.
1) Establish and maintain GLUT1 DS mouse breeding colony at USF Vivarium (Completed with active IACUC protocol).
2) Assess behavioral and histological effects of ketone esters (BHB and AcAc) on mouse model of GLUT1 DS (Ongoing).
3) Assess behavioral and histological effects of ketone mineral salts on mouse model of GLUT1 DS (Ongoing).
4) Dose response and combined ketone formulation studies.
5) Biochemical and histological analysis of blood and tissues.
Defining the Spatial and Temporal Requirements for the Glucose Transporter-1 protein in Glut1 Deficiency Syndrome
Umrao R. Monani, PhD
Associate Professor
Center for Motor Neuron Biology & Disease
Department of Pathology & Cell Biology
Columbia University Medical Center
New York, New York
Award Amount: $60,000
Glut1 deficiency syndrome (Glut1 DS) is rare, life-altering neurological disorder that strikes in early infancy and affects brain function. It is caused by mutations that inactivate one copy of the SLC2A1 gene and therefore deplete levels of the Glucose Transporter-1 (Glut1) protein that the gene encodes. Accordingly, patients suffer a multitude of disease effects including epileptic seizures, cognitive dysfunction and motor defects. There is currently little to suggest precisely what links paucity of the Glut1 protein to these abnormalities and no truly effective treatment for the disease. We are interested in the underlying biology of Glut1 DS as an eventual means to a safe, reliable and effective treatment for the disorder.
Our lab recently demonstrated that replacing the Glut1 gene in a mouse model of Glut1 DS using a virus (AAV9) as a delivery tool, is an effective way to treat the disease. Mice that are treated pre-symptomatically do not develop disease, whereas cohorts administered the therapeutic Glut1 gene once they are fully symptomatic do not appear to benefit from the treatment. Treatment during the early-symptomatic period offers significant protection. It is possible that human patients administered a ketogenic diet early during the course of the disease will respond similarly to early-symptomatic model mice, if restored for the Glut1 protein.
While these studies demonstrate that patients diagnosed and treated during the early phase of the disease will derive maximum benefit from agents that restore Glut1 expression to normal levels, it is not clear if an eventual treatment will perforce have to be chronic. The chronic use of drugs, even therapeutic ones, invariably trigger side-effects. Thus it is important to determine if a future treatment that involves raising Glut1 levels can be more limited in duration. This in turn requires a thorough understanding of the effects of low Glut1 protein during the course of life. Here, we wish to address this important question. To do so, we will use transgenic mice in which one can precisely time the depletion of Glut1 levels. Our gene therapy studies revealed that low Glut1 protein prevents the full development of the capillary network of the brain. We hypothesize that depletion of the protein while the network is expanding will adversely affect its development and trigger symptoms of Glut1 DS, whereas depleting the protein once the network is fully formed will be more benign. This will suggest that normal levels of Glut1 are particularly important as the capillary network of the brain is developing and warrant an aggressive treatment regimen during this period. However, it will also suggest that drug levels might be tapered once the capillary network of the brain attains its mature state (1 month in mice), without triggering disease. Part of our project will also involve using the transgenic mice to determine whether Glut1 is critically important only to cells that constitute the capillaries of the brain or if it is equally important in astrocytes – support cells for brain neurons. The collective outcome of the project could have important implications for the eventual design of an effective treatment for Glut1 DS.
Umrao R. Monani, PhD
Associate Professor
Center for Motor Neuron Biology & Disease
Department of Pathology & Cell Biology
Columbia University Medical Center
New York, New York
Award Amount: $60,000
Glut1 deficiency syndrome (Glut1 DS) is rare, life-altering neurological disorder that strikes in early infancy and affects brain function. It is caused by mutations that inactivate one copy of the SLC2A1 gene and therefore deplete levels of the Glucose Transporter-1 (Glut1) protein that the gene encodes. Accordingly, patients suffer a multitude of disease effects including epileptic seizures, cognitive dysfunction and motor defects. There is currently little to suggest precisely what links paucity of the Glut1 protein to these abnormalities and no truly effective treatment for the disease. We are interested in the underlying biology of Glut1 DS as an eventual means to a safe, reliable and effective treatment for the disorder.
Our lab recently demonstrated that replacing the Glut1 gene in a mouse model of Glut1 DS using a virus (AAV9) as a delivery tool, is an effective way to treat the disease. Mice that are treated pre-symptomatically do not develop disease, whereas cohorts administered the therapeutic Glut1 gene once they are fully symptomatic do not appear to benefit from the treatment. Treatment during the early-symptomatic period offers significant protection. It is possible that human patients administered a ketogenic diet early during the course of the disease will respond similarly to early-symptomatic model mice, if restored for the Glut1 protein.
While these studies demonstrate that patients diagnosed and treated during the early phase of the disease will derive maximum benefit from agents that restore Glut1 expression to normal levels, it is not clear if an eventual treatment will perforce have to be chronic. The chronic use of drugs, even therapeutic ones, invariably trigger side-effects. Thus it is important to determine if a future treatment that involves raising Glut1 levels can be more limited in duration. This in turn requires a thorough understanding of the effects of low Glut1 protein during the course of life. Here, we wish to address this important question. To do so, we will use transgenic mice in which one can precisely time the depletion of Glut1 levels. Our gene therapy studies revealed that low Glut1 protein prevents the full development of the capillary network of the brain. We hypothesize that depletion of the protein while the network is expanding will adversely affect its development and trigger symptoms of Glut1 DS, whereas depleting the protein once the network is fully formed will be more benign. This will suggest that normal levels of Glut1 are particularly important as the capillary network of the brain is developing and warrant an aggressive treatment regimen during this period. However, it will also suggest that drug levels might be tapered once the capillary network of the brain attains its mature state (1 month in mice), without triggering disease. Part of our project will also involve using the transgenic mice to determine whether Glut1 is critically important only to cells that constitute the capillaries of the brain or if it is equally important in astrocytes – support cells for brain neurons. The collective outcome of the project could have important implications for the eventual design of an effective treatment for Glut1 DS.
C7 and the Ketogenic Diet
Juan M. Pascual, MD, PhD
Associate Professor
Once Upon a Time Foundation Professorship in Pediatric Neurologic Diseases
Department of Neurology & Neurotherapeutics, Eugene McDermott Center for Human Growth and Development, Pediatrics, Physiology
Rare Brain Disorders Program Director
UT Southwestern Medical Center
Dallas, Texas
Award Amount: $50,000
We have used triheptanoin (C7) oil to treat Glut1 deficiency syndrome (Pascual et al. JAMA Neurol. 2014, 71:1255-65) in patients receiving a regular diet, who had no major side effects other than sporadic gastrointestinal intolerance. We will now investigate whether C7 can also be added to the ketogenic diet by simply replacing some of the ketogenic diet fat.
We want to test the compatibility of C7 with the ketogenic diet in patients who are prone to seizures (before or after the diet was initiated). The ultimate goal is to develop C7 as a safe complementary therapy to the ketogenic diet. The specific notion tested is that laboratory evidence that C7 may interfere with the ketogenic diet by inducing the formation of glucose in the liver, which is released into the bloodstream, potentially blocking ketosis.
Juan M. Pascual, MD, PhD
Associate Professor
Once Upon a Time Foundation Professorship in Pediatric Neurologic Diseases
Department of Neurology & Neurotherapeutics, Eugene McDermott Center for Human Growth and Development, Pediatrics, Physiology
Rare Brain Disorders Program Director
UT Southwestern Medical Center
Dallas, Texas
Award Amount: $50,000
We have used triheptanoin (C7) oil to treat Glut1 deficiency syndrome (Pascual et al. JAMA Neurol. 2014, 71:1255-65) in patients receiving a regular diet, who had no major side effects other than sporadic gastrointestinal intolerance. We will now investigate whether C7 can also be added to the ketogenic diet by simply replacing some of the ketogenic diet fat.
We want to test the compatibility of C7 with the ketogenic diet in patients who are prone to seizures (before or after the diet was initiated). The ultimate goal is to develop C7 as a safe complementary therapy to the ketogenic diet. The specific notion tested is that laboratory evidence that C7 may interfere with the ketogenic diet by inducing the formation of glucose in the liver, which is released into the bloodstream, potentially blocking ketosis.
