Faculty Bibliography

NGF has been suggested to play a role in urinary bladder dysfunction by mediating inflammation, as well as morphological and functional changes, in sensory and sympathetic neurons innervating the urinary bladder. To further explore the role of NGF in bladder sensory function, we generated a transgenic mouse model of chronic NGF overexpression in the bladder using the urothelium-specific uroplakin II (UPII) promoter. NGF mRNA and protein were expressed at higher levels in the bladders of NGF-overexpressing (NGF-OE) transgenic mice compared with wild-type littermate controls from postnatal day 7 through 12-16 wk of age. Overexpression of NGF led to urinary bladder enlargement characterized by marked nerve fiber hyperplasia in the submucosa and detrusor smooth muscle and elevated numbers of tissue mast cells. There was a marked increase in the density of CGRP- and substance P-positive C-fiber sensory afferents, neurofilament 200-positive myelinated sensory afferents, and tyrosine hydroxylase-positive sympathetic nerve fibers in the suburothelial nerve plexus. CGRP-positive ganglia were also present in the urinary bladders of transgenic mice. Transgenic mice had reduced urinary bladder capacity and an increase in the number and amplitude of nonvoiding bladder contractions under baseline conditions in conscious open-voiding cystometry. These changes in urinary bladder function were further associated with an increased referred somatic pelvic hypersensitivity. Thus, chronic urothelial NGF overexpression in transgenic mice leads to neuronal proliferation, focal increases in urinary bladder mast cells, increased urinary bladder reflex activity, and pelvic hypersensitivity. NGF-overexpressing mice may, therefore, provide a useful transgenic model for exploring the role of NGF in urinary bladder dysfunction

Banna viruses (BAVs) have been isolated from pigs, cattle, ticks, mosquitoes, and human encephalitis patients. We isolated and analyzed 20 BAVs newly isolated in China; this finding extends the distribution of BAVs from tropical zone to north temperate climates and demonstrate regional variations in BAV phylogeny and mosquito species possibly involved in BAV transmission.

Gold nanoparticles (AuNPs) are used in many applications; however, their interactions with cells and potential health risk(s) are not fully known. In this manuscript, we describe the interactions of AuNPs with human dermal fibroblasts and show that they can penetrate the plasma membrane and accumulate in large vacuoles. We also demonstrate that the uptake of the AuNPs is a function of time, their size and concentration. Specifically, we demonstrate that 45 nm AuNPs penetrate cells via clathrin-mediated endocytosis, while the smaller 13 nm enter mostly via phagocytosis. Furthermore, we provide evidence of cytoskeleton filament disruption as a result of AuNPs exposure and reconstitution during recovery (following AuNP removal), despite no changes in actin or beta-tubulin protein levels. In contrast, the expression of the extracellular matrix (ECM) proteins, collagen and fibronectin, was diminished in the cells exposed to AuNPs. We also examined the proliferation rates of cells exposed to AuNPs and show that its diminution is a function of apoptosis and speculate that apoptosis results from the number of vacuoles present in the cells, which is probably the main factor that disrupts the cytoskeleton causing cell area contraction and decreases in motility. Lastly, we also present data that indicates that AuNPs' damage to cells is not permanent and that the cells can completely recover as a function of AuNPs' size, concentration and exposure time. Taken together, our data suggest that AuNPs exert detrimental effects on cell function that could reverse following AuNPs removal.

Many signaling pathways that contribute to tumorigenesis are also functional in pregnancy, although they are dysregulated in the former and tightly regulated in the latter. Transformation-related protein 53 (Trp53), which encodes p53, is a tumor suppressor gene whose mutation is strongly associated with cancer. However, its role in normal physiological processes, including female reproduction, is poorly understood. Mice that have a constitutive deletion of Trp53 exhibit widespread development of carcinogenesis at early reproductive ages, compromised spermatogenesis, and fetal exencephaly, rendering them less amenable to studying the role of p53 in reproduction. To overcome this obstacle, we generated mice that harbor a conditional deletion of uterine Trp53 and examined pregnancy outcome in females with this genotype. These mice had normal ovulation, fertilization, and implantation; however, postimplantation uterine decidual cells showed terminal differentiation and senescence-associated growth restriction with increased levels of phosphorylated Akt and p21, factors that are both known to participate in these processes in other systems. Strikingly, uterine deletion of Trp53 increased the incidence of preterm birth, a condition that was corrected by oral administration of the selective COX2 inhibitor celecoxib. We further generated evidence to suggest that deletion of uterine Trp53 induces preterm birth through a COX2/PGF synthase/PGF(2alpha) pathway. Taken together, our observations underscore what we believe to be a new critical role of uterine p53 in parturition.

Genetic analyses previously implicated the matrix-localized protease ClpP in signaling the stress of protein misfolding in the mitochondrial matrix to activate nuclear-encoded mitochondrial chaperone genes in C. elegans (UPR(mt)). Here, we report that haf-1, a gene encoding a mitochondria-localized ATP-binding cassette protein, is required for signaling within the UPR(mt) and for coping with misfolded protein stress. Peptide efflux from isolated mitochondria was ATP dependent and required HAF-1 and the protease ClpP. Defective UPR(mt) signaling in the haf-1-deleted worms was associated with failure of the bZIP protein, ZC376.7, to localize to nuclei in worms with perturbed mitochondrial protein folding, whereas zc376.7(RNAi) strongly inhibited the UPR(mt). These observations suggest a simple model whereby perturbation of the protein-folding environment in the mitochondrial matrix promotes ClpP-mediated generation of peptides whose haf-1-dependent export from the matrix contributes to UPR(mt) signaling across the mitochondrial inner membrane

Arising from: Majo, F., Rochat, A., Nicolas, M., Jaoude, G. A. & Barrandon, Y. 456, 250-254 (2008).; Majo et al. replyThe longstanding concept that corneal epithelial stem cells reside mainly in the limbus is supported by the absence of major corneal epithelial differentiation markers, that is, K3 and K12 keratins, in limbal basal cells (these markers are expressed, however, in corneal basal cells, thus distinguishing the mode of keratin expression in corneal epithelium from that of all other stratified epithelia), the centripetal migration of corneal epithelial cells, the exclusive location of slow-cycling cells in the limbal basal layer, the superior in vitro proliferative potential of limbal epithelial cells, and the transplanted limbal cells' ability to reconstitute corneal epithelium in vivo (reviewed in refs 1-4). Moreover, previous data indicate that corneal and conjunctival epithelia represent two separate cell lineages (reviewed in refs 1-4). Majo et al. suggested, however, that corneal and conjunctival epithelia are equipotent, and that identical oligopotent stem cells are present throughout the corneal, limbal and conjunctival epithelia. We point out here that these suggestions are inconsistent with many known growth, differentiation and cell migration properties of the anterior ocular epithelia