Inhibition of p38 MAPK facilitates ex vivo expansion of skin epithelial progenitor cells

Ex vivo expansion of skin epithelial stem cells has long attracted great interest because of the potential utilization in transplantation and gene therapy. The use of cultured stem or progenitor cells was limited by the lack of applicable culturing system with both satisfactory expansion efficacy and well suppressed differentiation ex vivo. The p38 mitogen-activated protein kinase (MAPK) pathways are responsible for cell growth and differentiation process. We investigated the function of p38 inhibitor SB203580 in the ex vivo expansion of skin epithelial progenitor cells by comparing media with or without addition of this inhibitor. Our results showed that the culturing medium with murine 3T3 feeder layers added with 10 μM SB203580 was more effective in promoting clonal growth of human skin epithelial progenitors or stem cells than the conventional medium without SB203580. The clone initial day in cells treated with 10 μM SB203580 came 2 d earlier with higher colony formation efficiency. The skin epithelial progenitor cells treated with 10 μM SB203580 formed clones that were uniformly smaller in size, longer in sustained proliferation, shorter in clone doubling time, higher in S-phase cells percentage, and lower in levels of differentiation markers such as K10 along with higher levels of stem-cell-associated markers such as p63, K15, and ABCG2 than those cultured in the conventional medium. Collectively, these results indicate that the p38 MAPK pathways inhibitor SB203580 can be used as a culture medium additive that helps to achieve more effective ex vivo expansion of skin epithelial progenitor cells.     

Enhancement of rice production using endophytic strains of Rhizobium leguminosarum bv. trifolii in extensive field inoculation trials within the Egypt Nile delta

This study assessed the ability of biofertilizer inoculants containing Rhizobium leguminosarum bv. trifolii to enhance production of rice (Oryza sativa L.) under actual agricultural conditions in the Nile delta. Large-scale field experiments evaluated 5 rice varieties inoculated with 7 endophytic rhizobial strains during 5 growing seasons, including at sites ranked as the world’s highest in rice production. Inoculation with single strains or multi-strain consortia significantly increased grain yield in 19 of the 24 trials. By combining superior rhizobial inoculants with agricultural extension training, grain yield increased up to 47% in farmers’ fields, with an average increase of 19.5%. Data on rice straw production, harvest index and the agronomic fertilizer N-use efficiency also indicated positive agronomic benefits of rhizobial inoculation. These results establish the merit of deploying our biofertilization strategy using selected rhizobial strains to promote rice production capacity while reducing the need for additional chemical N-fertilizer inputs to maintain agricultural sustainability and acceptable production economy. Technology transfer of this important translational research can significantly help to alleviate hunger and meet the nutritional needs of many people in developing countries.     

Water-soluble PDE4 inhibitors for the treatment of dry eye

PDE4 inhibitors have the potential to alleviate the symptoms and underlying inflammation associated with dry eye. Disclosed herein is the development of a novel series of water-soluble PDE4 inhibitors. Our studies led to the discovery of coumarin 18, which is effective in a rabbit model of dry eye and a tear secretion test in rats.     

Stochastic disease dynamics of a hospital infection model

A stochastic model for hospital infection incorporating both direct transmission and indirect transmission via free-living bacteria in the environment is investigated. We examine the long term behavior of the model by calculating a stationary distribution and normal approximation of the distribution. The quasi-stationary distribution of the model is studied to investigate the models’ behavior before extinction and the time to extinction. Numerical results show agreement between the calculated distributions and results of event-driven simulations. Hand hygiene of volunteers is more effective in terms of reducing the mean (or standard deviation) of the stationary distribution of colonized patients and the expected time to extinction compared to hand hygiene of health care workers (HCWs), on the basis of our parameter values. However, the indirect (or direct) transmission rate can lead to either increase or decrease in the standard deviation of the stationary distribution, but the impact of the indirect transmission is much greater than that of the direct transmission. The findings suggest that isolation of new admitted colonized patients is most effective in reducing both the mean and standard deviation of the stationary distribution and measures related to indirect transmission are secondary in their effects compared to other interventions.     

ncRNA consensus secondary structure derivation using grammar strings

Many noncoding RNAs (ncRNAs) function through both their sequences and secondary structures. Thus, secondary structure derivation is an important issue in today's RNA research. The state-of-the-art structure annotation tools are based on comparative analysis, which derives consensus structure of homologous ncRNAs. Despite promising results from existing ncRNA aligning and consensus structure derivation tools, there is a need for more efficient and accurate ncRNA secondary structure modeling and alignment methods. In this work, we introduce a consensus structure derivation approach based on grammar string, a novel ncRNA secondary structure representation that encodes an ncRNA's sequence and secondary structure in the parameter space of a context-free grammar (CFG) and a full RNA grammar including pseudoknots. Being a string defined on a special alphabet constructed from a grammar, grammar string converts ncRNA alignment into sequence alignment. We derive consensus secondary structures from hundreds of ncRNA families from BraliBase 2.1 and 25 families containing pseudoknots using grammar string alignment. Our experiments have shown that grammar string-based structure derivation competes favorably in consensus structure quality with Murlet and RNASampler. Source code and experimental data are available at http://www.cse.msu.edu/~yannisun/grammar-string.     

The unusual conformation of cross-strand disulfide bonds is critical to the stability of β-hairpin peptides

The cross-strand disulfides (CSDs) found in β-hairpin antimicrobial peptides (β-AMPs) show a unique disulfide geometry that is characterized by unusual torsion angles and a short Cα-Cα distance. While the sequence and disulfide bond connectivity of disulfide-rich peptides is well studied, much less is known about the disulfide geometry found in CSDs and their role in the stability of β-AMPs. To address this, we solved the nuclear magnetic resonance (NMR) structure of the β-AMP gomesin (Gm) at 278, 298, and 310 K, examined the disulfide bond geometry of over 800 disulfide-rich peptides, and carried out extensive molecular dynamics (MD) simulation of the peptides Gm and protegrin. The NMR data suggests Cα-Cα distances characteristic for CSDs are independent of temperature. Analysis of disulfide-rich peptides from the Protein Data Bank revealed that right-handed and left-handed rotamers are equally likely in CSDs. The previously reported preference for right-handed rotamers was likely biased by restricting the analysis to peptides and proteins solved using X-ray crystallography. Furthermore, data from MD simulations showed that the short Cα-Cα distance is critical for the stability of these peptides. The unique disulfide geometry of CSDs poses a challenge to biomolecular force fields and to retain the stability of β-hairpin fold over long simulation times, restraints on the torsion angles might be required.     

Establishment of Human Patient-Derived Endometrial Cancer Xenografts in NOD scid Gamma Mice for the Study of Invasion and Metastasis

Objective

Most endometrial cancers are detected early and have a good prognosis, while some endometrial cancers are highly invasive, metastasize early, and respond suboptimally to therapy. Currently, appropriate model systems to study the aggressive nature of these tumors are lacking. The objective of this study was to establish a mouse xenograft model of endometrial tumors derived from patients in order to study the biological aggressive characteristics that underlie invasion and metastasis.

Methods

Endometrial tumor tissue fragments (1.5 mm×1.5 mm) from patients undergoing surgery, were transplanted under the renal capsule of NOD scid gamma mice. After 6–8 weeks, tumors were excised and serially transplanted into additional mice for propagation. Immunohistochemical analysis of the tumors was done for various tumor markers.

Results

Four cases of different subtypes of endometrial cancer were grown and propagated in mice. Three of the four tumor cases invaded into the kidneys and to adjacent organs. While all tumors exhibited minimal to no staining for estrogen receptor α, progesterone receptor staining was observed for tumor grafts. In addition, levels and localization of E-cadherin, cytokeratin and vimentin varied depending on subtype. Finally, all tumor xenografts stained positively for urokinase plasminogen activator while 3 tumor xenografts, which showed invasive characteristics, stained positively for urokinase plasminogen activator receptor.

Conclusion

Endometrial tumors transplanted under the renal capsule exhibit growth, invasion and local spread. These tumors can be propagated and used to study aggressive endometrial cancer.