Faculty Bibliography

To evaluate correlations between choroidal abnormalities, Lisch nodules, and age in patients with neurofibromatosis type 1 (NF1), we examined ten cases with NF1 using near-infrared reflectance imaging. Patients ranged in age from 4 to 39 years. The angle used for near-infrared reflectance imaging was 55 degrees . We counted the total number of choroidal abnormalities in an area within a 55 degrees angle centered on the fovea and the total number of Lisch nodules on the iris by slit-lamp examination. No positive correlation was found between the number of Lisch nodules and patient age (Spearman's rank correlation coefficient rho=0.117, P=0.7414). Choroidal abnormalities tended to increase with age (rho=0.6150), but this difference was not statistically significant (P=0.0650). A positive correlation was found between the number of choroidal abnormalities and Lisch nodules (rho=0.783, P=0.0267). In conclusion, choroidal abnormalities tend to increase with patient age and are correlated with the number of Lisch nodules.

The formation and maintenance of neuromuscular synapses requires a complex exchange of signals between motor neurons and skeletal muscle fibers leading to the formation of a highly specialized postsynaptic membrane and a highly differentiated nerve terminal. As a consequence, acetylcholine receptors (AChRs) become highly concentrated in the postsynaptic membrane and arranged in perfect register with active zones in the presynaptic nerve terminal, insuring for rapid, robust and reliable synaptic transmission. During development, motor axons approach and recognize muscle that is primed, or prepatterned in the prospective synaptic region. Muscle prepatterning is established by MuSK, a receptor tyrosine kinase, and Lrp4, a member of the LDLR family. Lrp4 associates with MuSK and stimulates MuSK kinase activity, increasing Lrp4 and MuSK expression and causing the clustering of Lrp4 and MuSK. Once clustered, Lrp4 functions as a direct retrograde signal for presynaptic differentiation, causing motor axons to stop growing and develop specializations required for neurotransmitter release. Nascent synapses are stabilized by neuronal Agrin, which is released by motor nerve terminals and binds to Lrp4, stimulating further association between Lrp4 and MuSK and increasing MuSK kinase activity. Lrp4 thus has a central role in coordinating synaptic differentiation, as Lrp4 not only binds Agrin and stimulates postsynaptic differentiation but also acts in turn as a direct retrograde signal for presynaptic differentiation. Mutations in Agrin, Lrp4 and MuSK, as well as additional genes that function in this signaling pathway, cause congenital myasthenia, and auto-antibodies to Lrp4, MuSK, or AChRs are responsible for myasthenia gravis. I will summarize experiments that have contributed to this model of neuromuscular synapse formation, indicate how this knowledge has provided insight into causes for neuromuscular disease, and describe a therapeutic approach for preserving synapses and treating neuromuscular diseases

All vertebrate eggs are surrounded by an extracellular coat that supports growth of oocytes, protects oocytes, eggs, and early embryos, and participates in the process of fertilization. In mammals (platypus to human beings) the coat is called a zona pellucida (ZP) and in non-mammals (molluscs to birds), a vitelline envelope (VE). The ZP and VE are composed of just a few proteins that are related to one another and possess a common motif, called the zona pellucida domain (ZPD). The ZPD arose more than ~600 million years ago, consists of ~260 amino acids, and has 8 conserved Cys residues that participate in 4 intramolecular disulfides. It is likely that egg-coat proteins are derived from a common ancestral gene. This gene duplicated several times during evolution and gave rise to 3-4 genes in fish, 5 genes in amphibians, 6 genes in birds, and 3-4 genes in mammals. Some highly divergent sequences, N- and C-terminal to the ZPD, have been identified in egg-coat proteins and some of these sequences may be under positive Darwinian selection that drives evolution of the proteins. These and other aspects of egg-coat proteins, including their structure and synthesis, are addressed in this review.

ADAMTS-12 is a member of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family of proteases, which were known to play important roles in various biological and pathological processes, such as development, angiogenesis, inflammation, cancer, arthritis, and atherosclerosis. In this review, we briefly summarize the structural organization of ADAMTS-12; concentrate on the emerging role of ADAMTS-12 in several pathophysiological conditions, including intervertebral disc degeneration, tumorigenesis and angioinhibitory effects, pediatric stroke, gonad differentiation, trophoblast invasion, and genetic linkage to schizophrenia and asthma, with special focus on its role in arthritis and inflammation; and end with the perspective research of ADAMTS-12 and its potential as a promising diagnostic and therapeutic target in various kinds of diseases and conditions.

Glioblastoma multiforme (GBM) is a deadly primary brain malignancy. Glioblastoma stem cells (GSC), which have the ability to self-renew and differentiate into tumor lineages, are believed to cause tumor recurrence due to their resistance to current therapies. A subset of GSCs is marked by cell surface expression of CD133, a glycosylated pentaspan transmembrane protein. The study of CD133-expressing GSCs has been limited by the relative paucity of genetic tools that specifically target them. Here, we present CD133-LV, a lentiviral vector presenting a single chain antibody against CD133 on its envelope, as a vehicle for the selective transduction of CD133-expressing GSCs. We show that CD133-LV selectively transduces CD133+ human GSCs in dose-dependent manner and that transduced cells maintain their stem-like properties. The transduction efficiency of CD133-LV is reduced by an antibody that recognizes the same epitope on CD133 as the viral envelope and by shRNA-mediated knockdown of CD133. Conversely, the rate of transduction by CD133-LV is augmented by overexpression of CD133 in primary human GBM cultures. CD133-LV selectively transduces CD133-expressing cells in intracranial human GBM xenografts in NOD.SCID mice, but spares normal mouse brain tissue, neurons derived from human embryonic stem cells and primary human astrocytes. Our findings indicate that CD133-LV represents a novel tool for the selective genetic manipulation of CD133-expressing GSCs, and can be used to answer important questions about how these cells contribute to tumor biology and therapy resistance.

It has been recently shown that N-ras plays a preferential role in immune cell development and function; specifically: N-ras, but not H-ras or K-ras, could be activated at and signal from the Golgi membrane of immune cells following a low level T-cell receptor stimulus. The goal of our studies was to test the hypothesis that N-ras and H-ras played distinct roles in immune cells at the level of the transcriptome. First, we showed via mRNA expression profiling that there were over four hundred genes that were uniquely differentially regulated either by N-ras or H-ras, which provided strong evidence in favor of the hypothesis that N-ras and H-ras have distinct functions in immune cells. We next characterized the genes that were differentially regulated by N-ras in T cells following a low-level T-cell receptor stimulus. Of the large pool of candidate genes that were differentially regulated by N-ras downstream of TCR ligation, four genes were verified in qRT-PCR-based validation experiments (Dntt, Slc9a6, Chst1, and Lars2). Finally, although there was little overlap between individual genes that were regulated by N-ras in unstimulated thymocytes and stimulated CD4(+) T-cells, there was a nearly complete correspondence between the signaling pathways that were regulated by N-ras in these two immune cell types.