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Archive - Oct 2, 2015

Drug in Class of Anti-Cancer Compounds (HDAC Inhibitors) Appears to Sharpen Memory

Can you imagine a drug that would make it easier to learn a language, sharpen your memory, and help those with dementia and Alzheimer's disease by rewiring the brain and keeping neurons alive? New Rutgers University research published in the September 23, 2015 issue of the Journal of Neuroscience found that a drug (RGFP966)administered to rats, made them more attuned to what they were hearing, able to retain and remember more information, and able to develop new connections that allowed these memories to be transmitted between brain cells. The Journal of Neuroscience article is titled “Histone Deacetylase Inhibition via RGFP966 Releases the Brakes on Sensory Cortical Plasticity and the Specificity of Memory Formation.” "Memory-making in neurological conditions like Alzheimer's disease is often poor or absent altogether, once a person is in the advanced stages of the disease," said Dr. Kasia M. Bieszczad, the lead author and Assistant Professor in Behavioral and Systems Neuroscience in the Department of Psychology at Rutgers. "This drug could rescue the ability to make new memories that are rich in detail and content, even in the worst-case scenarios." What happens with dementias such as Alzheimer's is that brain cells shrink and die because the synapses that transfer information from one neuron to another are no longer strong and stable. There is currently no therapeutic treatment available that reverses this situation. The drug being tested in this animal study is among a class known as histone deacetylase (HDAC) inhibitors, now being used in cancer therapies to stop the activation of genes that turn normal cells into cancerous ones. HDAC inhibitors, in general, act to transcriptionally activate certain genes and to inactivate certain other genes.

Two New Mutations Found in Dogs with Achromatopsia Support Gene Therapy Approach to Curing This Genetic Vision Disorder in Humans and Dogs; Supercomputer Analysis Reveals the Mutations Destabilize CNG Ion Channel Essential to Light Signal Transduction

Cyclic-nucleotide-gated (CNG) ion channels are key mediators underlying signal transduction in retinal and olfactory receptors. Genetic defects in the CNGA3 and CNGB3 genes, encoding two structurally related subunits of cone CNG channels, lead to achromatopsia. This is a congenital, autosomal recessive retinal disorder that manifests by cone photoreceptor dysfunction, severely reduced visual acuity, impaired or complete color blindness, and photophobia. The disorder often strikes people early in life, and currently there is no cure for the condition. In human achromatopsia, nearly 100 different mutations have already been identified in the CNGA3 gene alone. Famously, achromatopsia was the subject of a book titled “The Island of the Colorblind,” by neurologist/author Oliver Sacks, M.D. (see image of book jacket). In this work, Dr. Sacks described the surprising prevalence of a particular rare form of the disease (complete achromatopsia) on the remote Pacific atoll of Pingelap. It is believed that the disease on Pingelap can be traced back to a so-called “founder mutation” passed down from an early ruler, who was one of just approximately 20 Pingelap survivors of a 1775 typhoon that hit the atoll. Signifcant inbreeding amongst the Pingelapese is believed to be the reason that much of the island’s small population now suffers from the autosomal recessive disorder, which, in more outbred populations, is relatively rare. One of the most promising avenues for developing a cure for achromatopsi is believed to be gene therapy, but to develop such therapies it is necessary to create animal models of disease that closely replicate the human condition. In a new study, a collaboration between University of Pennsylvania (Penn) and Temple University scientists has identified two naturally occurring genetic mutations in dogs that result in achromatopsia.

Limb Blueprint Exists in Snake Genome; Surprising Finding Revealed by Enhancer Sequence Analysis in Boa Constrictor, Burmese Python, and King Cobra

When researchers at the University of Georgia (UGA) examined the genome of several different snake species, they found something surprising. Embedded in reptiles' genetic code was DNA that, in most animals, controls the development and growth of limbs--a strange feature for creatures that are famous for their long, legless bodies and distinctive slither. Now, they've found an explanation. In a paper published online on October 1, 2015 in the journal Developmental Cell, the scientists show that the same genetic tools responsible for limb development also control the formation of external genitalia, and that may help explain why snakes have held on to this limb circuitry through the ages. The article is titled “Shared Enhancer Activity in the Limbs and Phallus and Functional Divergence of a Limb-Genital cis-Regulatory Element in Snakes.” Snakes weren't always legless; they evolved the loss of limbs over 100 million years ago, said Douglas Menke, an Assistant Professor of Genetics in UGA's Franklin College of Arts and Sciences and senior author of the Developmental Cell paper. "There have been many millions of snake generations since they evolved a legless body, and we would generally expect the DNA associated with limb development to fade away or mutate to do another job, but that doesn't seem to have happened," he said. "Naturally, we wanted to know why snakes had retained DNA that they don't appear to need." In their experiments, Dr. Menke and postdoctoral researcher Dr. Carlos Infante examined specific regions of non-coding DNA known as enhancers--a kind of switch that controls the expression of genes, telling them when to turn on or off during embryonic development. The researchers followed patterns of enhancer activity in embryonic limbs and genitalia of mice and lizards.

“Questions & Answers about CRISPR”--Eminent Physician-Scientist Comments on Powerful Applications and Potential Risks of New Gene Editing Technology

by R. Sanders Williams, M.D., President, Gladstone Institutes, San Franciso, California

[BQ Editor’s Note: Gladstone Institutes has kindly granted BioQuick Online News the right to reprint an opinion article on the CRISPR gene editing technology authored by Gladstone Institutes president R. Sanders Williams, M.D. The article was published on September 23, 2015 on the organization's website (https://gladstone.org/about-us/news/questions-and-answers-about-crispr). In addition to his role as president, Dr. Williams is Gladstone's Robert W. and Linda L. Mahley Distinguished Professor, and he is also a Professor of Medicine at the University of California, San Francisco (UCSF). In this article, Dr. Williams outlines the powerful existing and potential applications of CRISPR technology, while also cautioning about certain risks that must be borne in mind. In particular, he calls for a moratorium on gene editing to alter the human germline until the CRISPR technology is fully understood and perfected, and until a broad consensus on guidelines for responsible use can be achieved Dr. Gladstone’s article is reproduced in full below.]