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Tag Archives: pheromone

Friday Science Review: October 16, 2009

A mixed bag of research reports but nonetheless important and significant…

How MS Drug Works: Glatiramir Acetate (COPAXONE®, Teva Pharmaceuticals) is used for the treatment of patients with Multiple Sclerosis, however, it is not clear how this drug works.  In this new study, researchers demonstrate that glatiramir acetate can regulate the formation of myelin, the protective sheath around nerve fibers that is compromised in MS patients.  Glatiramir acetate induces the formation of helper immune cells that produce nerve promoting molecules, which in turn stimulate the myelin repair process. The study was led by Dr. V. Wee Yong at the University of Calgary and appears in this week’s issue of The Proceedings of the National Academy of Sciences.

New Target to Fight Diabetes: In genetic knockouts of the Lkb1 gene specifically in beta cells, the insulin producing units in the pancreas, the knockout mice exhibited an increased number of beta cells that were also larger than normal with greater amounts of insulin.  When they challenged the knockout mice with a high-fat diet to try to induce diabetes, the mice responded and kept blood glucose levels down.  Lkb1 is a tumor suppressor gene that was also known to be involved in energy metabolism but it was unclear whether the Lkb1 protein was associated with diabetes.  Dr. Robert Screaton’s group at the Children’s Hospital of Eastern Ontario Research Institute answered this question in a report appearing in this week’s Cell Metabolism.  Also noteworthy is that a research team from Israel published a similar study leading to the same conclusions.  With these surprising and dramatic results, Lkb1 may represent another therapeutic avenue to treat or prevent diabetes.

Sialyltransferase Crystal Structure Solved: Many important proteins, lipids or sugars are modified by the addition of sialic acid and these steps are essential for a number of processes including cell recognition, cell adhesion and immunogenicity.  The key enzyme responsible for catalyzing this reaction is a set of related sialyltransferases (ST).  In a Nature Structural and Molecular Biology report published this week, Dr. Natalie Strynadka (University of British Columbia) describes solving the crystal structure of ST and provides the first detailed understanding of the enzyme.  Without getting into any molecular jargon, suffice it to say that the structural data brings insight into how the enzyme works and how it achieves specificity, which is useful knowledge for developing prospective inhibitors.

Power of Pheromones: Researchers removed the pheromone-producing cells in fruit flies (male or female) and found that these flies were extremely attractive to normal male fruit flies and also flies of other related species.  This contradicts the notion that these chemical signals simply attract one individual to another.  Instead, they are part of a complex signaling system used by the flies to recognize and distinguish sexes and species.  Other unusual behaviour by male fruit flies without pheromones included trying to copulate with each other’s heads.  Dr. Joel Levine and his team at the University of Toronto (Mississauga) describe their research in detail in this week’s edition of Nature.

Beta-globin Switch: A proteomics screen was used to identify the enzyme G9a as the interacting partner of NF-E2, which act together to control expression of the beta-globin genes in red blood cell development.  This study provides a clearer understanding of the molecular determinants controlling embryonic expression of beta-globin where G9a acts as a repressor and its transition to adult beta-globin expression where G9a promotes expression.  The research team at the Ottawa Hospital Research Institute was lead by Dr. Marjorie Brand and the study appears in the early online edition of the Proceedings of the National Academy of Sciences.

Friday Science Review: August 21, 2009

This week… cancers, brains, and fruit flies.

Combinatorial therapy to fight melanoma: Malignant melanomas are aggressive cancers that are highly resistant to chemotherapy, possibly due to high levels of Bcl-2 family anti-cell death  proteins.  Although the small molecule inhibitor, ABT-737, is effective against Bcl-2 family proteins in other cancers, it is not very effective in melanoma cases.  The reason may be due to overexpression of another protein, Mcl-1, which confers resistance to ABT-737.  When  Dr. Victor Tron’s group at Queen’s University combined ABT-737 treatment with inhibitions of Mcl-1 by way of siRNA knockdown, the cancer cells lost their resistance and underwent cell death.  These findings, appearing this week in PloS One , suggest that the combination of ABT-737 and Mcl-1 knockdown represents a promising, new treatment strategy for malignant melanoma.

Understanding Stat3 in Breast Cancer: Elevated Stat3 levels in breast cancer patients often correlate with poor clinical outcome.  To understand how Stat3 may influence cancer progression, a Stat3 knockout mouse was combined with a mouse expressing the mutant form of the breast cancer gene, ErbB2, and predisposed to develop breast tumours.  What the researchers at McGill University found was that without Stat3, breast cancer still developed but the malignancy of the mammary tumours decreased significantly with fewer animals having metastatic lesions in the lung.  Genetic profiling of the tumours showed that without Stat3, angiogenic and inflammatory responses, which often play an important role in the metastatic process, were blunted.  Remember, last week I noted an article on Par6 and TGFb in breast cancer metastasis.

This recent study, hot off the press in Cancer Research, was led by Dr. William Muller, one the early pioneers in using transgenic mouse technology.

Gene expression differences in suicide brains: This is the first study to perform global gene expression analysis on the brains of suicide cases to try to broaden the scope of suicide research to other neurotransmitter systems.  The serotonergic system is well studied as the primary area of the brain involved in suicides but there are likely other contributing factors.  Dr. Turecki’s research team at McGill University performed microarray expression studies on a number of brain tissue samples from the cortical and subcortical regions to identify potentially new molecular pathways involved in depression and suicide.  Their results revealed a number of alterations including genes involved in synaptic neurotransmission, namely upregulation of glutamatergic (excitatory) and GABAergic (inhibitory) related genes in suicide brains.  This report in PLoS One should open the research field into exploring alternate treatment methods and better understanding the development of suicide and depression.

Male hormone discovery: A new male-specific pheromone was identified on fruit flies.  When the researchers transferred some of the compound onto female fruit flies, the male flies were suddenly uninterested.  How did they identify this pheromone?  They exposed a fruit fly to a laser in a MALDI-type mass spectrometer instrument where ions are ejected into the instrument and analyzed.  Some previously unidentified compounds were discovered including this hormone.  The research was conducted at the University of Toronto Mississauga by Joel Levine and Jocelyn Millar and appears in this week’s Current Biology.

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