http://www.sciencedaily.com/releases/2009/04/090422132837.htm

ScienceDaily (Apr. 29, 2009) — An international study led by Ohio State University neuroscience researchers describes one of the missing triggers that controls calcium inside cells, a process important for muscle contraction, nerve-cell transmission, insulin release and other essential functions.

The research is being posted online April 22 in the journal Nature.

The researchers believe the findings will enhance the understanding of how calcium signals are regulated in cells and shed light on new ways to treat many diseases, including cardiovascular diseases, immune diseases, metabolic diseases, cancer, and brain disorders.

The study found that molecular structures called two-pore channels (TPCs) cause the release of calcium when stimulated by a substance called NAADP.

The researchers also show that TPCs are located in the membranes of cell components called lysosomes and endosomes. These are mobile structures within cells that were not previously thought to be sites of calcium release.

Furthermore, the discharge of calcium from these structures can prompt much larger releases from stores located on the large and elaborate membrane network called the endoplasmic reticulum.

“Our study discovered one of the missing targets for calcium signaling,” says Michael Xi Zhu, associate professor of neuroscience and a researcher with Ohio State’s Center for Molecular Neurobiology. “It also nails down that NAADP receptors are located on lysosomes and endosomes, which should change people’s views of calcium signaling.

“It’s as if we now understand that cells have not only a primary battery for calcium but other batteries in different places.”

Researchers have known for some time that NAADP, or nicotinic acid adenine dinucleotide phosphate, stimulates calcium release inside cells, but there was controversy about how this happened and where this calcium source was located.

Zhu, working with colleagues at the University of Edinburgh, the University of Oxford and UMDNJ-Robert Wood Johnson Medical School in New Jersey, used gene sequence information to discover first that TPC proteins should have the properties of a calcium channel.

The investigators tested their hypothesis in a series of experiments that involved boosting TPC levels – specifically, TPC2 – in a line of laboratory cells. They found that higher TPC2 levels corresponded to higher calcium levels in cells exposed to NAADP.

They used fluorescent antibody labeling to show that the TPC proteins are localized in the membranes of lysosomes and endosomes, which are two types of vesicles in cells. Lysosomes contain enzymes that digest materials and kill bacteria, while endosomes contain materials taken up from the external environment and internalized.

Finally, the researchers found that these NAADP-sensitive stores of calcium are tightly coupled to the larger calcium stores on the endoplasmic reticulum.

This work was supported by grants from the U.K. Wellcome Trust, British Heart Foundation, U.S. National Institutes of Health and American Heart Association.

http://www.sickkids.ca/AboutSickKids/News-Room/Past-News/2009/SickKids-Corporate-Ventures-office-licenses-new-news.html

The Hospital for Sick Children (SickKids) has licensed its rights to a new compound to Neuraltus Pharmaceuticals in order to further research and development, and move the technology into clinical trials. The compound, which was developed in collaboration with Neuraltus, may be useful in treating certain lysosomal storage disorders and neurological disorders.

Neuraltus approached Dr. Clifford Lingwood, Senior Scientist in the Molecular Structure & Function program at the SickKids Research Institute when they noticed synergies between work they were doing and a publication he had authored. After a year and a half of collaboration between the two groups, enough data was generated to patent the pharmaceutical technology and focus on the development of a novel compound for the treatment of lysosomal storage disorders.

“In a healthy human, cell structures called lysosomes process and breakdown unwanted substances inside the cell,” said Lingwood. “Individuals suffering from a lysosomal storage disorder have a build up of the unwanted substances within the cells.” This can lead to any of approximately 40 known lysosomal storage disorders with a wide variety of symptoms, including developmental delays, muscular disorders, seizures, deafness and blindness, and can end in death. Neuraltus and Lingwood will continue to perform research in hopes of developing the compound as a treatment for a number of these disorders.

The compound, collaboratively developed by Lingwood and Neuraltus, affects lysosomal storage disorders by reducing the rate at which a molecule called a glycolipid is created within the body. Overproduction of glycolipds can interfere with how the cells grow and mature, how the cells adhere to each other and their ability to prevent tumours from forming. This can lead to serious disorders like Tay-Sachs, Gaucher’s, and Fabry’s diseases.

After an initial patent application had been filed, the compound was also found to have an additional affect on neurodegenerative disorders, and researchers at the Parkinson’s Institute in Sunnyvale, CA joined the collaboration. Neurodegenerative disorders such as Parkinson’s disease damage or destroy cells in the brain and spinal cord, and can impede movement and interfere with memory and brain function. A patent application has also been filed for this new use for the compound.

The license for SickKids’s patent rights to the technology was developed and negotiated by SickKids’ Corporate Ventures office and is effective as of February 1. SickKids will continue to collaborate with Neuraltus and the Parkinson’s Institute to further develop the compound.

Discovery of new gene that stimulates the release of calcium in cells

International research collaborators have identified a new family of proteins, TPC2 (two-pore channels), that facilitates calcium signaling from specialized subcellular organelles.

The study, published today in Nature , is the first to isolate TPC2 as a channel that binds to nucleotide nicotinic acid adenine dinucleotide phosphate (NAADP), a second-signaling messenger, resulting in the release of calcium from intracellular stores. According to the researchers, this new discovery may have broad implications in cell biology and human disease research.

“The discovery was the result of many researchers working as one international team toward a unified outcome. We are very appreciative of all the collaborators’ efforts,” said Jianjie Ma, PhD, professor of physiology and biophysics at UMDNJ-Robert Wood Johnson Medical School. “We are proud to be part of a study that will stand as the foundation for further exploration of human disease, helping researchers to better understand how calcium contributes to cell growth and disorders, including aging-related cardiac disease, diabetes, lysosomal cell dysfunction and the metastasis of cells in cancer.”

According to the researchers, the mechanism for how NAADP triggers the release of calcium, as well as the specific sites of calcium store targeted for release, were previously unknown. These findings indicate that NAADP, through its interaction with TPC2, targets a specific store of calcium in lysosomes, a specialized subunit within the cell that contain digestion enzymes and regulate cell function.

The study was a collaboration of investigative teams at four universities, including the laboratory of Dr. Michael Zhu at the Ohio State University, the laboratory of Dr. A. Mark Evans at the University of Edinburgh and the laboratory of Dr. Antony Galione at the University of Oxford.

The research was supported by grants from the United Kingdom’s Wellcome Trust and the British Heart Foundation, the United States’ National Institutes of Health, and the American Heart Association.

UMDNJ-ROBERT WOOD JOHNSON MEDICAL SCHOOL
As one of the nation’s leading comprehensive medical schools, Robert Wood Johnson Medical School of the University of Medicine and Dentistry of New Jersey is dedicated to the pursuit of excellence in education, research, health care delivery, and the promotion of community health. In cooperation with Robert Wood Johnson University Hospital, the medical school’s principal affiliate, they comprise New Jersey’s premier academic medical center. In addition, Robert Wood Johnson Medical School has 34 hospital affiliates and ambulatory care sites throughout the region.

New information on molecular biology of KRas protein

KRas is one of the usual suspects in cancer. It is a protein that is mutated in 30% of human tumors and has been implicated in the regulation of many cell signalling pathways.

For this reason, it is one of the main focuses of attention of international basic research and it is difficult to publish new information relating to its molecular biology. Researchers from the Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and the University of Barcelona (UB) have discovered a new breakdown pathway for this protein. The results, which could mean a new form of signalling involving KRas, were published in the latest edition of the Journal of Cell Biology (184(6):863-79), where they merited an appearance on the front page of the journal and an editorial comment. This study is part of the doctoral thesis of Dr. Albert Lu and includes the participation of Dr. Oriol Bachs , Dr. Carles Enrich , Dr. Neus Agell and Dr. Francesc Tebar , researchers from IDIBAPS and the Department of Cell Biology, Immunology and Neuroscience of the Faculty of Medicine of the University of Barcelona. Researchers from the University of Kyoto also took part in the study.

The article describes how the KRas protein is actively transported from the cell membrane, where most of its known activity takes place, to the lysosomes. The lysosomes are organelles responsible for breaking down proteins; this breakdown pathway was unknown in the case of KRas. Thanks to videomicroscopy techniques using a confocal microscope and the fluorescence, resonance energy transfer (FRET) technique, the researchers have observed how the protein is brought inside the cell and transported to the lysosomes. The protein remains active during this journey through the interior of the cell, which leads to the suspicion that it continues to exercise its influence on signalling pathways relating to cell proliferation and the appearance of cancers.

The signalling pathways activated by KRas are highly complex. With the newly available data, it will be necessary to investigate whether the signals emitted on the way to the lysosomes have a different meaning for the cell than those generated from the membrane, the protein’s usual site of action. These results provide clues to stimulating the elimination of KRas, a line of research that might result in new therapeutic strategies against cancer and diseases in which the formation of lysosomes is abnormal, such as Niemann-Pick disease. KRas is already used in the diagnosis of diseases such as colon, lung and breast cancer. The better we understand its biology, the more we will know about how it appears and how this and other diseases can be combatted.

http://www.idibaps.ub.edu/

The effects of pH and iminosugar pharmacological chaperones on lysosomal glycosidase structure and stability.

Human lysosomal enzymes acid-beta-glucosidase (GCase) and acid-alpha-galactosidase (alpha-Gal A) hydrolyze, respectively, the sphingolipids glucosyl- and globotriaosyl- ceramide, and mutations in these enzymes lead to the lipid metabolism disorders Gaucher and Fabry disease. We have investigated the structure and stability of GCase and alpha-Gal A at the neutral-pH environment reflective of the endoplasmic reticulum and the acidic-pH environment reflective of the lysosome. These details are important for the development of pharmacological chaperone therapy for Gaucher and Fabry disease, in which small molecules bind mutant enzymes in the ER to enable the mutant enzyme to meet quality control requirements for lysosomal trafficking. We report crystal structures of apo GCase at pH 4.5, pH 5.5, and in complex with the pharmacological chaperone isofagomine (IFG) at pH 7.5. We also present thermostability analysis of GCase at pH 7.4 and pH 5.2 using differential scanning calorimetry. We compare our results with analogous experiments using alpha-Gal A and the chaperone 1-deoxygalactonijirimycin (DGJ), including the first structure of alpha-Gal A with DGJ. Both GCase and alpha-Gal A are more stable at lysosomal pH with and without their respective iminosugars bound, and notably, the GCase/IFG complex stability is pH sensitive. We show that the conformations of the active site loops in GCase are sensitive to ligand binding but not pH, whereas analogous galactose- or DGJ- dependent conformational changes in alpha-Gal A are not seen. Thermodynamic parameters obtained from alpha-Gal A unfolding indicate two-state, van’t-Hoff unfolding in the absence of the iminosugar at neutral and lysosomal pH, and non two-state unfolding in the presence of DGJ. Taken together, these results provide insight into how GCase and alpha-Gal A are thermodynamically stabilized by iminosugars, and suggest strategies for the development of new pharmacological chaperones for lysosomal storage disorders.

PMID: 19374450 [PubMed – as supplied by publisher]

UC and Partners Awarded $23 Million to Transform Discoveries Into Real-World Health Solutions

CINCINNATI—The University of Cincinnati (UC) and its affiliated health care partners will receive nearly $23 million from the National Institutes of Health (NIH) to bring innovations from the laboratory bench to the bedside and to applications within the community.

 

The five-year funding, awarded through the NIH’s institutional Clinical and Translational Science Awards (CTSA) program, will be used to support programming within UC’s Center for Clinical and Translational Science and Training (CCTST). Established in 2005 as a collaborative effort among UC, Cincinnati Children’s Hospital Medical Center, University Hospital and the Cincinnati Department of Veterans Affairs Medical Center, the CCTST is a research resource and “academic home” for clinical and translational scientists and programs.

 

UC is the first CTSA to be funded in 2009.

“Bench to bedside (translational research) is a common phrase in medicine, and turning laboratory findings into diagnostic tools or therapies for patients is the goal of academic medical centers,” said David Stern, MD, College of Medicine dean and UC vice president for health affairs. “The CTSA program is a clear recognition by the NIH of the need to speed up the translation of the important work happening at the basic scientific level, and UC’s award is indicative of the quality of scientific discovery happening on our campus and in the labs of our close partners.”

CTSA funding—expected to be given to only 60 institutions nationwide by 2012—will eventually replace the NIH’s General Clinical Research Center (GCRC) program and various other training programs.

 

UC’s NIH-supported GCRC, housed at Cincinnati Children’s Hospital Medical Center, with a satellite operation at the Cincinnati Department of Veterans Affairs Medical Center, is led by James Heubi, MD, of Cincinnati Children’s and UC’s department of pediatrics, and associate dean for clinical and translational research, and is credited with many research successes. UC faculty and Cincinnati Children’s and VA researchers working in the GCRC have been at the forefront of Reye’s Syndrome and Gaucher disease, and have used novel medications to treat rare diseases such as lymphangioleiomyomatosis (LAM) and Fanconi anemia.

 

“Successes already realized at our NIH-supported clinical research center are strong indicators of what Cincinnati researchers and clinicians will be able to do with continued support and an emphasis on translational research,” said Heubi, who leads UC’s CTSA effort and the CCTST with Joel Tsevat, MD, professor of medicine and associate dean for clinical and translational research.

 

Heubi and Tsevat expect to continue what’s been started with the CCTST and initiate additional partnerships that can help bring discoveries to application or engage the broader community in clinical and translational research efforts.

 

“The formation of the CCTST on UC’s campus more than three years ago has put us in a unique position to hit the ground running with this CTSA award,” says Tsevat. “Beyond serving our Academic Health Center, though, we plan to involve the community in clinical and translational research. Not only will we work to increase enrollment for our clinical studies, but we will also turn to the community for research topics. We envision a bi-directional relationship with the community.”

UC’s CCTST already offers research support, including study design and biostatistical expertise, individual and institutional training grant preparation assistance, clinical and translational research training, and funding opportunities for junior faculty so that they can develop their research programs and become viable candidates for larger awards from the NIH or other sources.

 

The CCTST has also helped departments obtain NIH training grants to support fellowship positions. Six of the 22 funded “T32” training grants on campus were obtained with CCTST assistance.

 

In addition to funding assistance, the CCTST—located on the 10^th floor of Cincinnati Children’s new “S” building—is working to track clinical and translational activity and create an environment for researchers that facilitates interdisciplinary collaboration. The center’s Research Central service provides investigators with consultations on their study design and execution of research projects.

 

The center also serves the university’s educational mission—helping to form the recently approved master of science in clinical and translational research program through UC’s environmental health department.

 

The governance committee leading UC’s CTSA effort includes Stern, Heubi and Tsevat, as well as James Anderson, president and CEO of Cincinnati Children’s; Sandra Degen, PhD, UC vice president for research; Lee Ann Liska, executive director of University Hospital; Linda Smith, director of the Cincinnati VA Medical Center; Arnold Strauss, MD, chair of UC’s department of pediatrics and director of the Cincinnati Children’s Research Foundation; and UC President Nancy Zimpher.

For more information about the CTSA Consortium, visit www.ctsaweb.org. To read more about clinical and translational research at UC, visit www.cctst.uc.edu. A news release from the National Center for Research Resources can be found at http://www.nih.gov/news/health/apr2009/ncrr-07.htm.