Faculty Bibliography

Exchange mechanisms across the blood-cerebrospinal fluid (CSF) barrier in the choroid plexuses within the cerebral ventricles control access of molecules to the central nervous system, especially in early development when the brain is poorly vascularised. However, little is known about their molecular or developmental characteristics. We examined the transcriptome of lateral ventricular choroid plexus in embryonic day 15 (E15) and adult mice. Numerous genes identified in the adult were expressed at similar levels at E15, indicating substantial plexus maturity early in development. Some genes coding for key functions (intercellular/tight junctions, influx/efflux transporters) changed expression during development and their expression patterns are discussed in the context of available physiological/permeability results in the developing brain. Three genes: Secreted protein acidic and rich in cysteine (Sparc), Glycophorin A (Gypa) and C (Gypc), were identified as those whose gene products are candidates to target plasma proteins to choroid plexus cells. These were investigated using quantitative- and single-cell-PCR on plexus epithelial cells that were albumin- or total plasma protein-immunopositive. Results showed a significant degree of concordance between plasma protein/albumin immunoreactivity and expression of the putative transporters. Immunohistochemistry identified SPARC and GYPA in choroid plexus epithelial cells in the embryo with a subcellular distribution that was consistent with transport of albumin from blood to cerebrospinal fluid. In adult plexus this pattern of immunostaining was absent. We propose a model of the cellular mechanism in which SPARC and GYPA, together with identified vesicle-associated membrane proteins (VAMPs) may act as receptors/transporters in developmentally regulated transfer of plasma proteins at the blood-CSF interface.

PURPOSE: To acquire and characterize cellular-resolved in vivo fluorescence images of optogenetic probes expressed in rodent retinal ganglion cells, by adapting a low-cost and simple fundus system based on a topical endoscope. METHODS: A custom endoscope-based fundus system was constructed (adapted from the design of Paques and colleagues). Bright field and fluorescence images were acquired from head-fixed transgenic mice expressing Channelrhodopsin2-eYFP, and Sprague Dawley rats virally transfected with the optogenetic probe GCaMP3. Images were compared to in vitro images of the same structures and were analyzed. RESULTS: The fundus system provides high-quality, high-resolution fluorescence images of the eye fundus that span the whole retina. The images allow resolving individual cells and axon bundles in the Channelrhodopsin2-eYFP mice and cellular-scale structures in the GCaMP3 expressing rats. The resolution in mouse eyes was estimated to be better than 20 mum (full width at half maximum) and is only marginally dependent on movement-related blurring. CONCLUSIONS: The fluorescence-endoscopy fundus system provides a powerful yet simple and widely accessible tool for obtaining cellular resolved fluorescent images of optogenetic and other fluorescent probes. TRANSLATIONAL RELEVANCE: The new system could prove to be a basic tool for non-invasive in vivo small animal retinal imaging in a wide array of translational vision applications, including the tracking of fluorescently tagged cells and the expression of gene-therapy and optogenetic vectors.

Tauopathy in the brain of patients with Alzheimer's disease starts in the entorhinal cortex (EC) and spreads anatomically in a defined pattern. To test whether pathology initiating in the EC spreads through the brain along synaptically connected circuits, we have generated a transgenic mouse model that differentially expresses pathological human tau in the EC and we have examined the distribution of tau pathology at different timepoints. In relatively young mice (10-11 months old), human tau was present in some cell bodies, but it was mostly observed in axons within the superficial layers of the medial and lateral EC, and at the terminal zones of the perforant pathway. In old mice (>22 months old), intense human tau immunoreactivity was readily detected not only in neurons in the superficial layers of the EC, but also in the subiculum, a substantial number of hippocampal pyramidal neurons especially in CA1, and in dentate gyrus granule cells. Scattered immunoreactive neurons were also seen in the deeper layers of the EC and in perirhinal and secondary somatosensory cortex. Immunoreactivity with the conformation-specific tau antibody MC1 correlated with the accumulation of argyrophilic material seen in old, but not young mice. In old mice, axonal human tau immunoreactivity, especially at the endzones of the perforant pathway, was greatly reduced. Relocalization of tau from axons to somatodendritic compartments and propagation of tauopathy to regions outside of the EC correlated with mature tangle formation in neurons in the EC as revealed by thioflavin-S staining. Our data demonstrate propagation of pathology from the EC and support a trans-synaptic mechanism of spread along anatomically connected networks, between connected and vulnerable neurons. In general, the mouse recapitulates the tauopathy that defines the early stages of AD and provides a model for testing mechanisms and functional outcomes associated with disease progression.

Recently, we had the opportunity to review the progress that has been made in the field of cardiovascular disease over the past century in The FASEB Journal and, based on those thoughts, in this article we predict what may transpire inthis 'century of biology'. Although it is true that 'the best way to predict the future is to invent it', we gaze through the prism of modern biomolecular science for a vision of a possible future and see cardiology practice that is transformed. In the second half of the 20th century, we developed a more fundamental understanding of atherosclerotic vascular disorders and invented life-saving therapeutics. We saw a similar development of mechanism-based pharmacotherapy to address heart failure, primarily through agents that antagonize the excessive concentration of circulating neurohumoral agents. Now we are in the midst of the device era, from stents to cardiac resynchronization therapy to transcatheter valves.The next wave of treatments will build on an increasingly sophisticated understanding of the molecular determinants of cardiovascular disorders and engineering feats that are barely perceptible now. Genomic profiling, molecular prescriptions for prevention and personalized therapeutics, regenerative medicine and the new field of cardiovascular tissue bioengineering will transform cardiovascular medicine. If the human species can survive threats of our own doing, such as the related epidemics of obesity and diabetes, by the turn of the next century, treatment of cardiovascular disease will not resemble the present in almost any way. Touch Medical Media 2012