Notch signaling is required for lateral induction of Jagged1 during FGF-induced lens fiber differentiation

AbstractPrevious studies of the developing lens have shown that Notch signaling regulates differentiation of lens fiber cells by maintaining a proliferating precursor pool in the anterior epithelium. However, whether Notch signaling is further required after the onset of fiber cell differentiation is not clear. This work investigates the role of Notch2 and Jagged1 (Jag1) in secondary fiber cell differentiation using rat lens epithelial explants undergoing FGF-2 dependent differentiation in vitro. FGF induced Jag1 expression and Notch2 signaling (as judged by the appearance of activated Notch2 Intracellular Domain (N2ICD)) within 12–24 h. These changes were correlated with induction of the Notch effector, Hes5, upregulation of N-cadherin (N-cad), and downregulation of E-cadherin (E-cad), a cadherin switch characteristic of fiber cell differentiation. Induction of Jag1 was efficiently blocked by U0126, a specific inhibitor of MAPK/ERK signaling, indicating a requirement for signaling through this pathway downstream of the FGF receptor. Other growth factors that activate MAPK/ERK signaling (EGF, PDGF, IGF) did not induce Jag1. Inhibition of Notch signaling using gamma secretase inhibitors DAPT and L-685,458 or anti-Jag1 antibody markedly decreased FGF-dependent expression of Jag1 demonstrating Notch-dependent lateral induction. In addition, inhibition of Notch signaling reduced expression of N-cad, and the cyclin dependent kinase inhibitor, p57Kip2, indicating a direct role for Notch signaling in secondary fiber cell differentiation. These results demonstrate that Notch-mediated lateral induction of Jag1 is an essential component of FGF-dependent lens fiber cell differentiation

Preparation and Culture of Rat Lens Epithelial Explants for Studying Terminal Differentiation

The anterior surface of the ocular lens is covered by a monolayer of epithelial cells, which proliferate in an annular zone underlying the ciliary body. Following division, these cells migrate posteriorly, where FGF diffusing from the retina induces them to differentiate into a posterior array of elongated lens fiber cells, which compose the bulk of the lens. Differentiation of lens epithelial cells into lens fibers can be induced in vitro by culturing explants of the central region of the anterior epithelium in the presence of FGF-2. Explants are prepared from lenses of neonatal rats by removing the lens from the eye and grasping the lens capsule on the posterior side with dissecting tweezers. The posterior capsule is then gently torn open and pressed down into the plastic bottom of a tissue culture dish. The peripheral regions of the explant are removed with a scalpel and the central area is then cultured in the presence of 100ng/ml FGF-2 for as long as 2-3 weeks, depending on the parameters to be studied. Since epithelial cells in cultured explants differentiate in approximate synchrony over a period of days to weeks, the time course of signaling and gene expression can be determined using molecular, biochemical, and pharmacological techniques. Immunofluorescence microscopy is a powerful adjunct to these methods as it demonstrates the subcellular localization of proteins of interest and can reveal the physiological consequences of experimental manipulations of signaling pathways

Persistence of Fimbrial Tissue on the Ovarian Surface Following Salpingectomy

BACKGROUND: Salpingectomy is recommended as a risk-reducing strategy for epithelial tubo-ovarian cancer. The gold standard procedure is complete tubal excision. OBJECTIVE: To assess the presence of residual fimbrial/tubal tissue on ovarian surfaces following salpingectomy. DESIGN: Prospective analysis of patients undergoing salpingo-oophorectomy +/- hysterectomy for benign indications, early cervical cancer or low risk endometrial cancer at a UK National Health Service Trust. Salpingectomy +/- hysterectomy was performed initially, followed by oophorectomy within the same operation. Separately retrieved tubes and ovaries were serially sectioned and completely examined histologically. The main outcome measure was histologically identified fimbrial/ tubal tissue on ovarian surface. Chi-square/Fisher's exact tests evaluated categorical variables (SPSS-23). RESULTS: 25 consecutive cases (mean age= 54.8 years (SD=5.0), comprising 41 adnexae (9= unilateral, 16= bilateral) were analysed. 17 (68.0%), 5 (20.0%) and 3 (12.0%), procedures were performed by consultant gynaecologists, subspecialty/specialist trainees and consultant gynaecological oncologists respectively. 12/25 (48.0%) were laparoscopic and 13/25 (52.0%) involved laparotomy. 4/25 (16.0%, CI: 4.5%, 36.1%) patients or 4/41 (9.8%, CI: 2.7%, 23.1%) adnexae showed residual microscopic fimbrial tissue on the ovarian surface. Tubes/ ovaries were free of adhesions in 23 cases. Two cases had dense adnexal adhesions but neither had residual fimbrial tissue on the ovary. Residual fimbrial tissue was not significantly associated with surgical route or experience; (consultant= 3/20 (15%), trainee= 1/5 (20%), p=1.0). CONCLUSION: Residual fimbrial tissue remains on the ovary following salpingectomy in a significant proportion of cases and could impact the level of risk-reduction obtained

Development of a Novel Virtual Screening Cascade Protocol to Identify Potential Trypanothione Reductase Inhibitors

The implementation of a novel sequential computational approach that can be used effectively for virtual screening and identification of prospective ligands that bind to trypanothione reductase (TryR) is reported. The multistep strategy combines a ligand-based virtual screening for building an enriched library of small molecules with a docking protocol (AutoDock, X-Score) for screening against the TryR target. Compounds were ranked by an exhaustive conformational consensus scoring approach that employs a rank-by-rank strategy by combining both scoring functions. Analysis of the predicted ligand-protein interactions highlights the role of bulky quaternary amine moieties for binding affinity. The scaffold hopping (SHOP) process derived from this computational approach allowed the identification of several chemotypes, not previously reported as antiprotozoal agents, which includes dibenzothiepine, dibenzooxathiepine, dibenzodithiepine, and polycyclic cationic structures like thiaazatetracyclo-nonadeca-hexaen-3-ium. Assays measuring the inhibiting effect of these compounds on T. cruzi and T. brucei TryR confirm their potential for further rational optimization

Publication Records of Faculty Promoted to Professor: Evidence from the UK Accounting and Finance Academic Community

This study investigates the publication profiles of 140 accounting and finance faculty promoted to the senior rank of professor at UK and Irish universities during the period 1992 to 2007. On average, approximately 9 papers in Association of Business Schools (ABS) (2008)-listed journals, with 5 at the highest 3*/4* quality levels in a portfolio of 20 outputs are required for promotion to professor. Multivariate analysis provides evidence that publication requirements in terms of ABS ranked journal papers have increased over time, an effect attributed to the government research assessment exercise. There is no evidence that requirements differ for: internal versus external promotion, male versus female candidates; accounting versus finance professors, research intensity of institution peer group; or government research ranking of unit. There is also no evidence of a substitution effect in relation to increased recent publication history, quantity of non-ABS outputs or sole-authorship, all of which show a significant complementary effect. It is noted that there is very limited overlap in the UK and US publication journal sets, suggesting underlying geographically-based paradigm differences. The benchmarks provided in this study are informative in a range of decision settings: recruitment; those considering making an application for promotion to a chair and those involved in promotion panels; cross-disciplinary comparisons; and resource allocation. The evidence presented also contributes to the emerging policy debates concerning the aging demographic profile of accounting faculty, the management of academic labour and the Research Excellence Framework

Dynamics of notch pathway expression during mouse testis post-natal development and along the spermatogenic cycle

Articles in International JournalsThe transcription and expression patterns of Notch pathway components (Notch 1–3, Delta1 and 4, Jagged1) and effectors (Hes1, Hes2, Hes5 and Nrarp) were evaluated (through RT-PCR and IHC) in the mouse testis at key moments of post-natal development, and along the adult spermatogenic cycle. Notch pathway components and effectors are transcribed in the testis and expressed in germ, Sertoli and Leydig cells, and each Notch component shows a specific cell-type and timewindow expression pattern. This expression at key testis developmental events prompt for a role of Notch signaling in prepubertal spermatogonia quiescence, onset of spermatogenesis, and regulation of the spermatogenic cycle

In-Vivo Expression Profiling of Pseudomonas aeruginosa Infections Reveals Niche-Specific and Strain-Independent Transcriptional Programs

Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics. To gain insights into the physiology of P. aeruginosa during infection, we assessed the transcriptional programs of three different P. aeruginosa strains directly after isolation from burn wounds of humans. We compared the programs to those of the same strains using two infection models: a plant model, which consisted of the infection of the midrib of lettuce leaves, and a murine tumor model, which was obtained by infection of mice with an induced tumor in the abdomen. All control conditions of P. aeruginosa cells growing in suspension and as a biofilm were added to the analysis. We found that these different P. aeruginosa strains express a pool of distinct genetic traits that are activated under particular infection conditions regardless of their genetic variability. The knowledge herein generated will advance our understanding of P. aeruginosa virulence and provide valuable cues for the definition of prospective targets to develop novel intervention strategies

Mutations in ARSB in MPS VI patients in India

Mucopolysaccharidosis VI (MPS VI) is an autosomal recessive inborn error of metabolism caused by mutations in the arylsulfatase B gene (ARSB) and consequent deficient activity of ARSB, a lysosomal enzyme. We present here the results of a study undertaken to identify the mutations in ARSB in MPS VI patients in India. Around 160 ARSB mutations, of which just 4 are from India, have been reported in the literature. Our study covered nine MPS VI patients from eight families. Both familial mutations were found in seven families, and only one mutation was found in one family. Seven mutations were found — four novel (p.G38_G40del3, p.C91R, p.L98R and p.R315P), two previously reported from India (p.D53N and p.W450C), and one reported from outside India (p.R160Q). One mutation, p.W450C, was present in two families, and the other six mutations were present in one family each. Analysis of the molecular structure of the enzyme revealed that most of these mutations either cause loss of an active site residue or destabilize the structure of the enzyme. The only previous study on mutations in ARSB in Indian MPS VI patients, by Kantaputra et al. 2014 [1], reported four novel mutations of which two (p.D53N and p.W450C) were found in our study as well. Till date, nine mutations have been reported from India, through our study and the Kantaputra study. Eight out of these nine mutations have been found only in India. This suggests that the population studied by us might have its own typical set of mutations, with other populations equally likely to have their own set of mutations