The cells characterizing healthy metazoa bodies are meant to share and maintain the same genome, with tissue diversity being originated by differential gene expression and alternative mRNA splicing during transcription. Few exceptions exist in this paradigm, the most prominent being that of B ant T cells, which are able to rearrange genomic DNA through somatic recombination and generate the huge variability of immunoglobulin and T cell receptor (TCR) repertoires.
On the other hand, the brains of patients affected by neurodegenerative diseases often display mosaicism -the presence of mutations and different copies of certain genes in the tissue cells- which does not depend on mutations inherited by parents: for examples, the neurons of patients with Alzheimer's disease (AD) display more DNA and different copies of the amiloid precursor protein (APP) gene, which is one of the causes of this condition. Although this feature is common in neurodegenerative pathologies, its mechanism is basically unknown. In this sense, the paper published this week on Nature by Lee et al represents an important milestone of molecular biology and neuroscience: it provides a mechanistic base for neuronal mosaicism of patients with AD and other neurodegenerative conditions, proving that neuron can indeed perform somatic recombination (a feature that to date was thought to be exclusive of immune cells), while it also lays new ground to understand neurodegeneration.
Brexit is possibly one of the most difficult situations ever faced by United Kingdom in recent times. Nobody has a clear prediction for what its long-term consequences are going to be for the country, should UK definitely decide to leave EU, but what has been pretty clear in these past months is that, among those who advocated Brexit, few saw the big picture and the full spectrum of the repercussion that this event would have had on the country's health, economy and, quite relevant to our cause, science.
Starting (and hopefully, ending) a PhD studentship is undoubtedly a thrilling -though demanding- task that is meant to teach students to cope with the hard work that is at the base of a research job. As someone new to several different duties -often performed at the same time- a PhD student can underestimate the magnitude of his tasks, and be overwhelmed by them.
Disfunctions of the gut-brain axis are increasingly emerging as an important factor in several pathologies, including neurodegenerative ones. These alterations are able to act on peripheral and central nervous system by disrupting physiological, immune and inflammatory. In particular, functional alterations in the gut have been linked, in the past, to the pathogenesis and prevalence of neurodegenerative conditions such as Parkinson's disease (PD), in which misfolded alpha-synuclein accumulates in the brain resulting, eventually, in the neuronal loss at the substantia nigra that is the basis of the motor impairment of this condition. Rather curiously, gastrointestinal alterations represent a quite common and often early symptom in PD, while the prevalence of this disease has been reported to be lower in patients that underwent gut surgical treatments such as partial vagotomy (the partial severing of a portion of the vagal nerve that innervates the gastroenteric tube, performed in the management of peptic ulcer); this led to the yet controversial theory that PD might harbour its seeds in the gut, before climbing its way up to the brain by propagating misfolded alpha-synuclein aggregates through the vagal nerve, in a sort of twisted "telephone game".
Peer reviewing is a pivotal part of scientific publication process, and it's meant to ensure that the data collected by researchers is properly scrutinized to find majour flaws or incoherences in the theory or methodology behind it. Nonetheless, nowaday, scientists receive little -if any- training in this, and most of the ability to analyze and review a scientific paper comes from raw experience.
The pathogenesis of multiple sclerosis (MS) lays its base on an self-directed attack of the immune system that goes haywire, as it attacks neuron myelin sheets and destroys them. This lack of capacity of the immune system of discriminating self antigens from microbial structures, which in turn unleashes auto-immunity, seems to be based on several factors, including the inheritance of particular HLA genes (HLA-DR15 is responsible, alone, for 60% of the genetic risk in MS), which govern T cell expansion, as well as a tendency of T and B cells to replicate independently of specific and direct antigen exposure. Among other things, an important pathogenetic event seems to be represented by the ability of T and B cells to engage in a HLA-TCR synapse that leads to autoproliferation of both lineages and eventually to IFN-gamma-dependent signals that, in turn, trigger macrophage-dependent myelin damage. In light of this, B and T cell proliferation, represents a central topic of interest in undestanding MS pathogenesis.
Glial cells are present in the brain roughly in an equal proportions to neurons, although such a ratio can vary significantly between different regions. They are central in several homeostatic and developmental aspects of the central nervous system and include oligodendrocytes progenitors and mature oligodendrocytes, astrocytes, and the "immune guests" of the CNS - the microglial cells, all of which display considerable morphological and functional variability, according to several recent investigations.