Neuroscience: The brain in glorious Technicolor
With a combination of genetic tricks and fancy proteins, researchers have colourfully labelled hundreds of individual neurons with distinctive hues to create a ‘Brainbow’. The research, takes mapping to a new level, and results in the labelling of neurons with approximately 90 different colour combinations.
Over a hundred years ago, Ramon Y Cajal’s use of Golgi staining on nerve cells opened the gates to modern neuroscience, but until now it has been tough to map out individual cells in each neuronal circuit. Jeff Lichtman and colleagues have developed the Technicolor version of Golgi staining, Brainbow, allowing more detailed reconstructions of brain circuits. This provides a key step towards modelling how the nervous system works normally and in diseased brains.
CONTACT
Jeff Lichtman (Harvard University, Cambridge, Ma, USA)
Tel: +1 617 496 8943; E-mail: jeff@mcb.harvard.edu
Showing posts with label USA. Show all posts
Showing posts with label USA. Show all posts
Thursday, November 01, 2007
Monday, October 29, 2007
Responding to sepsis
How quickly key receptors are activated on blood vessel cells can determine whether one survives or succumbs to sepsis.
Sepsis, a potentially life-threatening immune response to blood-borne infections, leads to loss of blood vessel function, resulting in shock and multiorgan failure. Athan Kuliopulos and colleagues looked to see if inhibition or activation of a receptor called PAR1 could limit the severity of sepsis. Mice injected with bacteria directly into the bloodstream developed sepsis and died; however, these mice were protected if given a PAR1 inhibitor within 4 hours.
The surprise came if PAR1 was inhibited at later times, as this failed to protect these mice; rather, activation of PAR1 at these later times ‘protected’ mice from toxic shock. The authors show this ‘late’ activation of PAR1 induces another PAR receptor to become activated. This establishes a protective effect by instructing cells lining the blood vessel to maintain tight junctions and averting the widespread edema and intravascular blood clotting that accompanies shock.
These findings might lead to successful therapies for patients with sepsis and other systemic inflammatory responses.
Author contact:
Athan Kuliopulos (Tufts-New England Medical Center, Boston, MA, USA)
Tel: +1 617 636 8482; E-mail: athan.kuliopulos@tufts.edu
How quickly key receptors are activated on blood vessel cells can determine whether one survives or succumbs to sepsis.
Sepsis, a potentially life-threatening immune response to blood-borne infections, leads to loss of blood vessel function, resulting in shock and multiorgan failure. Athan Kuliopulos and colleagues looked to see if inhibition or activation of a receptor called PAR1 could limit the severity of sepsis. Mice injected with bacteria directly into the bloodstream developed sepsis and died; however, these mice were protected if given a PAR1 inhibitor within 4 hours.
The surprise came if PAR1 was inhibited at later times, as this failed to protect these mice; rather, activation of PAR1 at these later times ‘protected’ mice from toxic shock. The authors show this ‘late’ activation of PAR1 induces another PAR receptor to become activated. This establishes a protective effect by instructing cells lining the blood vessel to maintain tight junctions and averting the widespread edema and intravascular blood clotting that accompanies shock.
These findings might lead to successful therapies for patients with sepsis and other systemic inflammatory responses.
Author contact:
Athan Kuliopulos (Tufts-New England Medical Center, Boston, MA, USA)
Tel: +1 617 636 8482; E-mail: athan.kuliopulos@tufts.edu
Long live transplants!
A new strategy to improve transplant survival in diabetic patients. In some individuals, Type 1 diabetes can be treated by transplanting pancreatic islets, but long-term survival of the transplants has been difficult to achieve. Islet grafts are rejected by the immune system, and efforts to increase their survival are usually aimed at dampening immune T-cell function.
Because B cells—another type of immune cell—may also play a role in graft rejection, Ali Naji and colleagues tested the effect of depleting B cells in monkeys transplanted with islet allografts. The authors found that rituximab, a B-cell depleting antibody approved for the treatment of Non-Hodgkin’s Lymphoma and rheumatoid arthritis, in combination with T-cell depleting therapy could extend survival of the grafts in some animals.
Long-term graft survival also normalized blood sugar levels, suggesting that B-cell depletion should be studied further for its potential benefit to therapies aimed at improving survival of islet transplants used to treat Type 1 diabetes.
Author contact:
Ali Naji (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 662 2066; E-mail: ali.naji@uphs.upenn.edu
A new strategy to improve transplant survival in diabetic patients. In some individuals, Type 1 diabetes can be treated by transplanting pancreatic islets, but long-term survival of the transplants has been difficult to achieve. Islet grafts are rejected by the immune system, and efforts to increase their survival are usually aimed at dampening immune T-cell function.
Because B cells—another type of immune cell—may also play a role in graft rejection, Ali Naji and colleagues tested the effect of depleting B cells in monkeys transplanted with islet allografts. The authors found that rituximab, a B-cell depleting antibody approved for the treatment of Non-Hodgkin’s Lymphoma and rheumatoid arthritis, in combination with T-cell depleting therapy could extend survival of the grafts in some animals.
Long-term graft survival also normalized blood sugar levels, suggesting that B-cell depletion should be studied further for its potential benefit to therapies aimed at improving survival of islet transplants used to treat Type 1 diabetes.
Author contact:
Ali Naji (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 662 2066; E-mail: ali.naji@uphs.upenn.edu
Phosphorylation on demand
A new chemical biology tool that explores protein modifications is presented in a paper online.These results will provide the framework for determining the biological function of many important biochemical signals.
Proteins are frequently encoded with special amino acid tags to send them to different parts of the cell; alternatively, proteins can be modified with a variety of small chemical compounds that cause them to move within the cell.
Peter G. Schultz and colleagues now study this process in the case of the protein Pho4 by introducing an unusual amino acid to the protein chain inside the cell. This amino acid looks like serine – one of the amino acids that is used to make proteins – except it is blocked by a bulky group that can be removed with light. Once exposed, the serine can be phosphorylated, or modified by the addition of a phosphate group, by a normal cellular process. The authors discovered that, out of five important serines in the protein sequence, one has particular importance in controlling whether the protein is sent out of the nucleus or not. This technique offers a powerful new method for monitoring the function of phosphorylation.
Author contact:
Peter G. Schultz (The Scripps Research Institute, La Jolla, CA, USA)
Tel: +1 858 784 9300, Email: schultz@scripps.edu
A new chemical biology tool that explores protein modifications is presented in a paper online.These results will provide the framework for determining the biological function of many important biochemical signals.
Proteins are frequently encoded with special amino acid tags to send them to different parts of the cell; alternatively, proteins can be modified with a variety of small chemical compounds that cause them to move within the cell.
Peter G. Schultz and colleagues now study this process in the case of the protein Pho4 by introducing an unusual amino acid to the protein chain inside the cell. This amino acid looks like serine – one of the amino acids that is used to make proteins – except it is blocked by a bulky group that can be removed with light. Once exposed, the serine can be phosphorylated, or modified by the addition of a phosphate group, by a normal cellular process. The authors discovered that, out of five important serines in the protein sequence, one has particular importance in controlling whether the protein is sent out of the nucleus or not. This technique offers a powerful new method for monitoring the function of phosphorylation.
Author contact:
Peter G. Schultz (The Scripps Research Institute, La Jolla, CA, USA)
Tel: +1 858 784 9300, Email: schultz@scripps.edu
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