Stem Cell Revolution: Regenerating the Eye

Research is breaking new ground that promises to change our ability to treat eye disease forever.

Although stem cells were discovered in the mid-1800s and the subject of experimentation in the early 1900s, it’s only been in recent decades that they’ve truly caught the imagination of medical researchers and the public. Today, our understanding of these cells is expanding dramatically, and research has proliferated as their potential has become clear. Nevertheless, stem cell research is still in its infancy. Because a host of basic questions remain unanswered, research around the world is moving in multiple directions, testing many different possible ways to derive stem cells and apply them in vitro for research and in vivo for treating or preventing disease.

A stem cell is defined as an undifferentiated cell that has the potential to become a number of specific cell types. However, depending on the derivation of the stem cell, its fundamental characteristics may be significantly different. There are four primary stem cell types: embryonic, taken from very early fertilized embryos; parthenogenetic, taken from unfertilized eggs with a simpler genetic sequence for researchers to manage; so-called adult stem cells, found in different organs and designed to differentiate into the cell types found in that organ only; and induced pluripotent stem cells, which are differentiated cells (for example, skin cells) that are coaxed into returning to an undifferentiated state, from which they may then evolve into any number of other cell types. Each type of stem cell has specific advantages and drawbacks that make it better suited—at least in theory—for specific applications.

As is often the case in medical research, the eye has become a popular target. That’s partly because results are typically easier to monitor in the eye than in other organs, and partly because much of the eye in immune-privileged, making it receptive to treatments that might trigger rejection in other parts of the body. Current targets include the retina, cornea, trabecular meshwork and simply stabilizing abnormal blood vessels.

Review of Ophthalmology Online, Sept 6, 2012

Clue to Cause of Alzheimer's Dementia Found in Brain Samples

Researchers at Washington University School of Medicine in St. Louis have found a key difference in the brains of people with Alzheimer's disease and those who are cognitively normal but still have brain plaques that characterize this type of dementia.
The new study, available online inAnnals of Neurology, still implicates amyloid beta in causing Alzheimer's dementia, but not necessarily in the form of plaques. Instead, smaller molecules of amyloid beta dissolved in the brain fluid appear more closely correlated with whether a person develops symptoms of dementia. Called amyloid beta "oligomers," they contain more than a single molecule of amyloid beta but not so many that they form a plaque.
Science Daily, Oct 22, 2012
Esparza TJ et al.

Amyloid-beta oligomerization in Alzheimer dementia versus high-pathology controls.

Annals of Neurology, Sept. 1, 2012

Humans can learn new information during sleep

During sleep, humans can strengthen previously acquired memories, but whether they can acquire entirely new information remains unknown. The nonverbal nature of the olfactory sniff response, in which pleasant odors drive stronger sniffs and unpleasant odors drive weaker sniffs, allowed us to test learning in humans during sleep. Using partial-reinforcement trace conditioning, the authors paired pleasant and unpleasant odors with different tones during sleep and then measured the sniff response to tones alone during the same nights' sleep and during ensuing wake. They found that sleeping subjects learned novel associations between tones and odors such that they then sniffed in response to tones alone. Moreover, these newly learned tone-induced sniffs differed according to the odor pleasantness that was previously associated with the tone during sleep. This acquired behavior persisted throughout the night and into ensuing wake, without later awareness of the learning process. Thus, humans learned new information during sleep.

Anat Arzi, Noam Sobel et al.
Nature Neuroscience 15, 1460–1465 (2012) doi:10.1038/nn.3193

Published online 26 August 2012

Multisensory brain mechanisms of bodily self-consciousness

Recent research has linked bodily self-consciousness to the processing and integration of multisensory bodily signals in temporoparietal, premotor, posterior parietal and extrastriate cortices. Studies in which subjects receive ambiguous multisensory information about the location and appearance of their own body have shown that these brain areas reflect the conscious experience of identifying with the body (self-identification (also known as body-ownership)), the experience of where 'I' am in space (self-location) and the experience of the position from where 'I' perceive the world (first-person perspective). Along with phenomena of altered states of self-consciousness in neurological patients and electrophysiological data from non-human primates, these findings may form the basis for a neurobiological model of bodily self-consciousness

Olaf Blanke

Nature Reviews Neuroscience 13, 556-571 (August 2012) | doi:10.1038/nrn3292

XENON100 announced the new results from 225 days data

The XENON100 collaboration submitted a paper with the new results of a 225 days to PRL, excluding previously unexplored parameter space and questioning the light WIMP interpretation of the DAMA and CoGeNT results.

The preprint can be found here:

http://arxiv.org/abs/1207.5988

Emerging roles of non-coding RNAs in brain evolution, development, plasticity and disease

Novel classes of small and long non-coding RNAs (ncRNAs) are being characterized at a rapid pace, driven by recent paradigm shifts in our understanding of genomic architecture, regulation and transcriptional output, as well as by innovations in sequencing technologies and computational and systems biology. These ncRNAs can interact with DNA, RNA and protein molecules; engage in diverse structural, functional and regulatory activities; and have roles in nuclear organization and transcriptional, post-transcriptional and epigenetic processes. This expanding inventory of ncRNAs is implicated in mediating a broad spectrum of processes including brain evolution, development, synaptic plasticity and disease pathogenesis.

Irfan A. Qureshi, et al.
Nature Reviews Neuroscience 13, 528-541 (August 2012) | doi:10.1038/nrn3234

The Attention System of the Human Brain: 20 Years After

Here, the author update their 1990 Annual Review of Neuroscience article, “The Attention System of the Human Brain.” The framework presented in the original article has helped to integrate behavioral, systems, cellular, and molecular approaches to common problems in attention research. Research on orienting and executive functions has supported the addition of new networks of brain regions. Developmental studies have shown important changes in control systems between infancy and childhood. In some cases, evidence has supported the role of specific genetic variations, often in conjunction with experience, that account for some of the individual differences in the efficiency of attentional networks. The findings have led to increased understanding of aspects of pathology and to some new interventions.

Steven E. Petersen and Michael I. Posner
The Attention System of the Human Brain: 20 Years AfterAnnual Review of Neuroscience
Vol. 35: 73-89 (Volume publication date July 2012)
First published online as a Review in Advance on April 12, 2012
DOI: 10.1146/annurev-neuro-062111-150525

piRNAs Can Trigger a Multigenerational Epigenetic Memory in the Germline of C. elegans

Transgenerational effects have wide-ranging implications for human health, biological adaptation, and evolution; however, their mechanisms and biology remain poorly understood. Here, we demonstrate that a germline nuclear small RNA/chromatin pathway can maintain stable inheritance for many generations when triggered by a piRNA-dependent foreign RNA response in C. elegans. Using forward genetic screens and candidate approaches, we find that a core set of nuclear RNAi and chromatin factors is required for multigenerational inheritance of environmental RNAi and piRNA silencing. These include a germline-specific nuclear Argonaute HRDE1/WAGO-9, a HP1 ortholog HPL-2, and two putative histone methyltransferases, SET-25 and SET-32. piRNAs can trigger highly stable long-term silencing lasting at least 20 generations. Once established, this long-term memory becomes independent of the piRNA trigger but remains dependent on the nuclear RNAi/chromatin pathway. Our data present a multigenerational epigenetic inheritance mechanism induced by piRNAs.

Alyson Ashe et al.

Cell. 2012 July 6; 150(1): 88–99.
doi: 10.1016/j.cell.2012.06.018

Higgs Particle has been discovered by LHC!

Finally the Higgs Particle has been discovered by LHC!
Here is the Higgs -> two gamma decay, observed by CMS.
The paper is available here.

Early Events in Axon/Dendrite Polarization

Differentiation of axons and dendrites is a critical step in neuronal development. Here we review the evidence that axon/dendrite formation during neuronal polarization depends on the intrinsic cytoplasmic asymmetry inherited by the postmitotic neuron, the exposure of the neuron to extracellular chemical factors, and the action of anisotropic mechanical forces imposed by the environment. To better delineate the functions of early signals among a myriad of cellular components that were shown to influence axon/dendrite formation, the authors discuss their functions by distinguishing their roles as determinants, mediators, or modulators and consider selective degradation of these components as a potential mechanism for axon/dendrite polarization. Finally, we examine whether these early events of axon/dendrite formation involve local autocatalytic activation and long-range inhibition, as postulated by Alan Turing for the morphogenesis of patterned biological structure.

Pei-lin Cheng and Mu-ming Poo
Annual Review of Neuroscience
Vol. 35: 181-201 (Volume publication date July 2012)
DOI: 10.1146/annurev-neuro-061010-113618