Children born with rare, inherited conditions known as Congenital Disorders of Glycosylation, or CDG, have mutations in one of the many enzymes the body uses to decorate its proteins and cells with sugars. Properly diagnosing a child with CDG and pinpointing the exact sugar gene that’s mutated can be a huge relief for parents—they better understand what they’re dealing with and doctors can sometimes use that information to develop a therapeutic approach. Whole-exome sequencing, an abbreviated form of whole-genome sequencing, is increasingly used as a diagnostic for CDG.
The three children in this study, from left to right: Oliver, Edward, and Amira-Zoe.
Muscle from normal mice (left) and a mouse model lacking ERRgamma and ERRbeta (right) differ in muscle fiber-type, as indicated by immunofluorescence staining (green = myosin heavey chain 1, blue = myosin heavy chain 2a)
Sanford-Burnham researchers identify microRNAs as the missing link between the two defining features of muscle fitness—fuel-burning and fiber-type switching—providing a potential new target for interventions that boost fitness in people with chronic illness or injury.
Researchers discovered that small pieces of genetic material called microRNAs link the two defining characteristics of fit muscles: the ability to burn sugar and fat and the ability to switch between slow- and fast-twitch muscle fibers. The team used two complementary mouse models—the “marathon mouse” and the “couch potato mouse”—to make this discovery. But what’s more, they also found that active people have higher levels of one of these microRNAs than sedentary people. These findings, published May 8 in The Journal of Clinical Investigation, suggest microRNAs could be targeted for the development of new medical interventions aimed at improving muscle fitness in people with chronic illness or injury.
Left: In fat tissue from a lean mouse, neutrophil elastase and a1-antitrypsin levels are balanced. Right: In fat tissue from an obese mouse, they are imbalanced—neutrophil elastase levels are high (dark staining) and a1-antitrypsin levels are low.
Imbalance between an enzyme called neutrophil elastase and its inhibitor causes inflammation, obesity, insulin resistance, and fatty liver in mice and humans—providing a new therapeutic target for these health conditions
Many recent studies have suggested that obesity is associated with chronic inflammation in fat tissues. In a new study, researchers discovered that an imbalance between an enzyme called neutrophil elastase and its inhibitor causes inflammation, obesity, insulin resistance, and fatty liver disease. This enzyme is produced by white blood cells called neutrophils, which play an important role in the body’s immune defense against bacteria.
Prostate cancer cells expressing a mutant form of c-Myc that cannot be altered by PKCzeta (left) are more aggressive and more invasive than prostate cancer cells in which PKCzeta is able to keep tabs on c-Myc (right).
The enzyme PKCζ acts as a tumor suppressor by keeping the pro-tumor c-Myc gene in check, in both mice and humans.
Researchers have identified how an enzyme called PKCζ suppresses prostate tumor formation. The finding, which also describes a molecular chain of events that controls cell growth and metastasis, could lead to novel ways to control disease progression.
Neurons from a normal mouse (left) are longer and fuller than neurons from a mouse lacking SNX27 (right).
Researchers discover that the extra chromosome inherited in Down syndrome impairs learning and memory because it leads to low levels of SNX27 protein in the brain.
What is it about the extra chromosome inherited in Down syndrome—chromosome 21—that alters brain and body development? Researchers have new evidence that points to a protein called sorting nexin 27, or SNX27. SNX27 production is inhibited by a molecule encoded on chromosome 21. The study, published March 24 in Nature Medicine, shows that SNX27 is reduced in human Down syndrome brains. The extra copy of chromosome 21 means a person with Down syndrome produces less SNX27 protein, which in turn disrupts brain function. What’s more, the researchers showed that restoring SNX27 in Down syndrome mice improves cognitive function and behavior.
Skeletal myospheres ("mini muscles") generated by adding MyoD and BAF60C to embryonic stem cells
To make “mini muscles” from stem cells, you need the protein BAF60C.
Pier Lorenzo Puri, Ph.D., and his team study what makes a muscle cell just that—a muscle cell. They’re especially interested in applying that information to regenerate new muscle for people with muscular dystrophy.
Last year, the team discovered that two proteins called MyoD and BAF60C work together to mark the DNA of precursor cells, setting them on a course to become muscle cells. When the MyoD/BAF60c complex receives the right signals, it unwinds the cell’s genome and begins the process of producing muscle-specific proteins. This chain of events eventually triggers these precursor cells—those that hang out in our normal muscle tissue—to mature into new muscle cells.
Siah2 levels (brown staining) are high in human castration-resistant prostate cancer (left), as compared to benign prostate growths (right)
Researchers discover that a protein called Siah2 helps prostate cancer cells resist hormone therapy—making it an attractive biomarker and therapeutic target.
Hormonal therapies can help control advanced prostate cancer for a time. However, for most men, at some point their prostate cancer eventually stops responding to further hormonal treatment. This stage of the disease is called androgen-insensitive or castration-resistant prostate cancer. In a study published March 18 in Cancer Cell, a research team found a mechanism at play in androgen-insensitive cells that enables them to survive treatment. They discovered that a protein called Siah2 keeps a portion of androgen receptors constantly active in these prostate cancer cells. Androgen receptors—sensors that receive and respond to the hormone androgen—play a critical role in prostate cancer development and progression.
3D structure of HNF-4α, a protein mutated in MODY1, a rare, inherited form of diabetes, reveals new pockets that could be targeted with therapeutic drugs
Researchers have determined the complete three-dimensional structure of a protein called HNF-4α. HNF-4α controls gene expression in the liver and pancreas, switching genes on or off as needed. People with mature onset diabetes of the young (MODY1), a rare form of the disease, have inherited mutations in the HNF-4α protein. This first-ever look at HNF-4α’s full structure, published today in Nature, uncovers new information about how it functions. The study also reveals new pockets in the protein that could be targeted with therapeutic drugs aimed at alleviating MODY1.
Neuron
In stroke and other neurological disorders, nitric oxide damages neurons and blocks the brain’s ability to self-repair
Nitric oxide, a gaseous molecule produced in the brain, can damage neurons. When the brain produces too much nitric oxide, it contributes to the severity and progression of stroke and neurodegenerative diseases such as Alzheimer’s. Researchers at Sanford-Burnham Medical Research Institute recently discovered that nitric oxide not only damages neurons, it also shuts down the brain’s repair mechanisms. Their study was published February 4 by the Proceedings of the National Academy of Sciences.
“In this study, we’ve uncovered new clues as to how natural chemical reactions in the brain can contribute to brain damage—loss of memory and cognitive function—in a number of diseases,” said Stuart A. Lipton, M.D., Ph.D., director of Sanford-Burnham’s Del E. Webb Center for Neuroscience, Aging, and Stem Cell Research and a clinical neurologist.
Lipton led the study, along with Sanford-Burnham’s Tomohiro Nakamura, Ph.D., who added that these new molecular clues are important because “we might be able to develop a new strategy for treating stroke and other disorders if we can find a way to reverse nitric oxide’s effect on a particular enzyme in nerve cells.”
Cells proliferating in an intestinal tumor
Researchers discover that tumors lacking the protein PKCζ are good at surviving when nutrients are scarce—opening a new therapeutic avenue that targets cancer metabolism.
Cancer cells need food to survive and grow. They’re very good at getting it, too, even when nutrients are scarce. Many scientists have tried killing cancer cells by taking away their favorite food, a sugar called glucose. Unfortunately, this treatment approach not only fails to work, it backfires—glucose-starved tumors actually get more aggressive. In a study published January 31 in the journal Cell, researchers discovered that a protein called PKCζ is responsible for this paradox. The research suggests that glucose depletion therapies might work against tumors as long as the cancer cells are producing PKCζ.
PKCζ: critical regulator of tumor metabolism
According to this study, when PKCζ is missing from cancer cells, tumors are able to use alternative nutrients. What’s more, the lower the PKCζ levels, the more aggressive the tumor.
“We found an interesting correlation in colon cancers—if a patient’s tumor doesn’t produce PKCζ, he has a poorer prognosis than a similar patient with the protein. We looked specifically at colon cancer in this study, but it’s likely also true for other tumor types,” said Jorge Moscat, Ph.D., a professor at Sanford-Burnham. Moscat led the study in close collaboration with colleague Maria Diaz-Meco, Ph.D.
In this study, researchers used an ARVD/C patient's skin cells to make induced pluripotent stem cells. Then they used those stem cells to generate ARVD/C patient-specific heart cells (shown here in green). These heart cells provide a valuable “disease in a dish” model that can be used to study ARVD/C and test new treatments.
Most patients with an inherited heart condition known as arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) don’t know they have a problem until they’re in their early 20s. The lack of symptoms at younger ages makes it very difficult for researchers to study how ARVD/C evolves or to develop treatments.
A new stem cell-based technology created by 2012 Nobel Prize winner Shinya Yamanaka, M.D., Ph.D., helps solve this problem. With this technology, researchers can generate heart muscle cells from a patient’s own skin cells. However, these newly made heart cells are mostly immature. That raises questions about whether or not they can be used to mimic a disease that occurs in adulthood.
In a paper published January 27 in Nature, researchers unveil the first maturation-based “disease in a dish” model for ARVD/C. The model was created using Yamanaka’s technology and a new method to mimic maturity by making the cells’ metabolism more like that in adult hearts. For that reason, this model is likely more relevant to human ARVD/C than other models and therefore better suited for studying the disease and testing new treatments.
Potential cancer drug sabutoclax blocks Bcl-2 protein family members that help keep cancer cells alive. This image shows the structure of one Bcl-2 protein, known as Bcl-Xl. (Image courtesy of the Pellecchia laboratory)
Researchers find that certain types of drug-resistant leukemia stem cells are vulnerable to sabutoclax, a novel cancer stem cell-targeting drug based on Sanford-Burnham research.
New experiments show that sabutoclax, a novel cancer stem cell-targeting drug that grew out of research at Sanford-Burnham Medical Research Institute, in combination with other therapies, could effectively treat diseases like chronic myeloid leukemia (CML). Sabutoclax might also lower the chance of relapse.
“The demonstration of sabutoclax’s preclinical activity in mouse models of CML is exciting and encourages further evaluation of this promising drug candidate for aggressive leukemias. We look forward to continuing our collaborative studies of sabutoclax, as we move this drug closer to the clinic,” said John Reed, M.D., Ph.D., professor and Donald Bren Chief Executive Chair at Sanford-Burnham.
Sabutoclax was first discovered as a result of research in the laboratories of Reed and his Sanford-Burnham colleague, Maurizio Pellecchia, Ph.D. The pair is now working with biotechnology company Oncothyreon Inc to develop sabutoclax into a potential anti-cancer drug. This latest study of sabutoclax’s efficacy, published January 17 in the journal Cell Stem Cell, was led by Catriona Jamieson, M.D., Ph.D., at UC San Diego Moores Cancer Center, in collaboration with Reed, Pellecchia and others.
Cardiac fibrosis (shown in purple), a hallmark of heart disease, is clearly increased in fruit flies on a high-sugar diet (right), as compared to flies on a normal diet (left).
First fruit fly model of diet-induced type 2 diabetes shows how high-sugar diet affects the heart and reveals new therapeutic opportunities
Regularly consuming sucrose—the type of sugar found in many sweetened beverages—increases a person’s risk of heart disease. In a study published January 10 in the journal PLOS Genetics, researchers at Sanford-Burnham Medical Research Institute and Mount Sinai School of Medicine used fruit flies, a well-established model for human health and disease, to determine exactly how sucrose affects heart function. In addition, the researchers discovered that blocking this cellular mechanism prevents sucrose-related heart problems.
“Our study reveals a number of specific sugar-processing enzymes that could be targeted with therapies aimed at reducing sucrose’s unhealthy effects on the heart,” said Karen Ocorr, Ph.D., research assistant professor at Sanford-Burnham and the study’s corresponding author.
Left: healthy beta cells. Right: type 2 diabetic beta cells lose their glucose-sensing capability as glucose transporters (green) are internalized due to environmental disturbances brought about by fat and obesity.
A new computational model of sugar transport in the pancreas reveals a metabolic “tipping point” in type 2 diabetes—a discovery that may form the basis for new efforts to prevent and treat the disease.
Changes in cellular metabolism play a bigger role in the development of type 2 diabetes than previously thought—perhaps an even larger part than genetic predisposition plays in the disease. That’s what Sanford-Burnham and UC Santa Barbara researchers concluded in a study published recently in the journal PLOS ONE. The team, including Jamey Marth, Ph.D., developed a computational model to better understand the underlying causes and progression of type 2 diabetes. The model revealed a metabolic “tipping point” that, when crossed, prevents the pancreas from adequately sensing blood sugar and secreting insulin. The team expects the discovery will form the basis for new efforts to prevent and treat type 2 diabetes.
Researchers discover that the genes active in a person’s belly fat are significantly different from those in his or her thigh fat, a finding that could shift the way we approach unwanted belly fat—from banishing it to relocating it.
Men tend to store fat in the abdominal area, but don’t usually have much in the way of hips or thighs. Women, on the other hand, are more often pear-shaped—storing more fat on their hips and thighs than in the belly.
Why are women and men shaped differently?
The answer still isn’t clear, but it’s an issue worth investigating, says Steven Smith, M.D., director of the Florida Hospital – Sanford-Burnham Translational Research Institute for Metabolism and Diabetes. That’s because belly fat is associated with higher risks of heart disease and diabetes. On the other hand, hip and thigh fat don’t seem to play a special role in these conditions.