Regenerating Dead Cells In the Brain with Stem Cells

Neuroscientists at the Université Libre De Bruxelles (ULB) in Belgium have taken a very important step in cell therapy for diseases of the brain. This team generated cortical neurons from embryonic stem cells, which they then used to treat adult with brain problems. This research was recently published in the journal Neuron.

The ULB team was led by Pierre Vanderhaeghen, Kimmo Michelsen and Sandra Acosta (ULB Neuroscience Institute, in collaboration with the laboratory of Afsaneh Gaillard (INSERM/U. Poitiers, France). These results open new perspectives for the repair of damaged cells in the brain and replacing damage neurons.

The cerebral cortex is definitely the most complex and essential structure of our brain. The nerve cells or neurons that compose the cerebral cortex are the basic building blocks that help it do every job that it does. The loss of loss of cortical neurons is the cause of many neurological diseases as a result of stroke, Alzheimer disease, or physical trauma to the brain can seriously compromise brain function.

Previously, these same ULB researchers discovered how to generate cortical neurons in the laboratory cortical neurons from embryonic stem cells. Despite the triumph of these findings, it was completely unclear whether these findings could be translated into a living creature.

Now, the ULB team has successfully tested the use of their laboratory-generated cortical neurons in a living animal. In this study, Vanderhaeghen and others transplanted cortical pyramidal neurons made from embryonic stem cells into the brains of adult mice who had undergone chemically induced brain damage. This experiment cause rather massive neuronal losses in the visual cortex.

Remarkably, the implanted neurons integrated effectively into the brain after injury, but most importantly they could connect with the host brain, and some of them even responded to visual stimuli, like the visual cortex.

Integration only occurred, if the types of implanted neurons were matched to the lesioned area. In other words, since visual cortex neurons were lost, only the implantation of other cortical neurons allowed the cells to properly engraft into the visual cortex. However the grafted neurons displayed long-range patterns of connectivity with the host neurons.

This remains an experimental approach that has, to date, only been successfully performed with laboratory mice. A good deal more much research is required before any clinical application in humans will come to the clinic. Regardless, the success of these experiments combining cell engineering to generate nerve cells in a controlled and unlimited fashion, together with transplantation in to damaged brain, opens new avenues to repair the brain following damage or degeneration, such as following stroke or brain trauma.

Stem Cell Structure and Obesity

New research conducted at Queen Mary University of London (QMUL) has discovered that the regulation of the length of primary cilia, which are small hair-like projections on the surfaces of most cells, can prevent the production of fat cells taken from adult human bone marrow. Such a discovery might be used to develop a way of preventing obesity.

What are primary cilia?  For many years, almost all attention was focused on cilia that moved because their function was readily observable.  However, Alexander Kowalevsky first reported in 1867 the presence of single (nonmotile) cilia in a variety of vertebrate cells.  These solitary and nonmotile cilia are far more widespread than the motile type.  In humans, only a few cell types have motile cilia, namely epithelial cells in the bronchi and oviducts, and ependymal cells that line brain vesicles.  However, virtually all other cells have a primary cilium.

What makes primary cilia different from the motile form? First, they lack the central pair of microtubules, which would explain the lack of motility.  Primary cilia also seem to lack dynein, one of the molecular motors needed for motility.  In addition, some primary cilia do not project beyond the cell surface, and most, but not all, are very short.  What do these organelles do if they are not sticking out of the cell, or motile?

Further work has shown that primary cilia are important in intracellular transport and also in sensory function for cells.  Now it seems that primary cilia are also important in the process of adipogenesis.

Primary cilia

Adipogenesis refers to the differentiation of stem cells into fat cells. The QMUL research team showed that during adipogenesis, the length of primary cilia increases, which increases the movement of specific proteins associated with the cilia. When the QMUL team genetically restricted primary cilia elongation by genetic means, they were able to stop the formation of new fat cells.

One of the lead authors or this study, Melis Dalbay, said that it was the first time that subtle changes in primary cilia structure can influence the differentiation of stem cells into fat.

Since the length of primary cilia can be influenced by various factors including pharmaceuticals, inflammation and even mechanical forces, this study provides new insight into the regulation of fat cell formation and obesity.

This research points toward a new type of treatment known as “cilia-therapy” where manipulation of primary cilia may be used in the future to treat a growing range of conditions including obesity, cancer, inflammation and arthritis.