Is the Cannabinoid CB2 Receptor a Major Regulator of the Neuroinflammatory Axis of the Neurovascular Unit in Humans?

The central nervous system (CNS) is an immune privileged site where the neurovascular unit (NVU) and the blood-brain barrier (BBB) act as a selectively permeable interface to control the passage of nutrients and inflammatory cells into the brain parenchyma. However, in response to injury, infection, or disease, CNS cells become activated, and release inflammatory mediators to recruit immune cells to the site of inflammation. Increasing evidence suggests that cannabinoids may have a neuroprotective role in CNS inflammatory conditions. For many years, it was widely accepted that cannabinoid receptor type 1 (CB1) modulates neurological function centrally, while peripheral cannabinoid receptor type 2 (CB2) modulates immune function. As knowledge about the physiology and pharmacology of the endocannabinoid system advances, there is increasing interest in targeting CB2 as a potential treatment for inflammation-dependent CNS diseases (Ashton & Glass, 2007), where recent rodent and human studies have implicated intervention at the level of the NVU and BBB. These are incredibly important in brain health and disease. Therefore, this review begins by explaining the cellular and molecular components of these systems, highlighting important molecules potentially regulated by cannabinoid ligands and then takes an unbiased look at the evidence in support (or otherwise) of cannabinoid receptor expression and control of the NVU and BBB function in humans.

Improving active contour methods for tracking endothelial cells by the removal of low-confidence edge segments.

Previously we developed an active contour method for segmenting and tracking cells in phase-contrast microscopy images. Our method is capable of fine-grained segmentation on noisy image sequences. In this paper, we improve the active contour segmentation model to provide better accuracy, by selectively identifying areas of the contour with low confidence and removing them. The method is applied to HMEC-1 cells (human microvascular endothelial cells). The segmentation provided by the method is quantitavely compared with manually-drawn contours, showing close fit and capability to 'lock' on to cell boundaries for hundreds of frames.

Patterning and detailed study of human hNT astrocytes on parylene-C/silicon dioxide substrates to the single cell level.

It is estimated that the adult human brain contains 100 billion neurons with 5-10 times as many astrocytes. Although it has been generally considered that the astrocyte is a simple supportive cell to the neuron, recent research has revealed new functionality of the astrocyte in the form of information transfer to neurons of the brain. In our previous work we developed a protocol to pattern the hNT neuron (derived from the human teratocarcinoma cell line (hNT)) on parylene-C/SiO(2) substrates. In this work, we report how we have managed to pattern hNT astrocytes, on parylene-C/SiO(2) substrates to single cell resolution. This article disseminates the nanofabrication and cell culturing steps necessary for the patterning of such cells. In addition, it reports the necessary strip lengths and strip width dimensions of parylene-C that encourage high degrees of cellular coverage and single cell isolation for this cell type. The significance in patterning the hNT astrocyte on silicon chip is that it will help enable single cell and network studies into the undiscovered functionality of this interesting cell, thus, contributing to closer pathological studies of the human brain.

First human hNT astrocytes patterned to single cell resolution on parylene-C/silicon dioxide substrates.

In our previous work we developed a successful protocol to pattern the human hNT neuron (derived from the human teratocarcinoma cell line (hNT)) on parylene-C/SiO(2) substrates. This communication, reports how we have successfully managed to pattern the supportive cell to the neuron, the hNT astrocyte, on such substrates. Here we disseminate the nanofabrication, cell differentiation and cell culturing protocols necessary to successfully pattern the first human hNT astrocytes to single cell resolution on parylene-C/SiO(2) substrates. This is performed for varying parylene strip widths providing excellent contrast to the SiO(2) substrate and elegant single cell isolation at 10 µm strip widths. The breakthrough in patterning human cells on a silicon chip has widespread implications and is valuable as a platform technology as it enables a detailed study of the human brain at the cellular and network level.