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21.
Adipose-derived stem cells (ASCs) are clinically important in regenerative medicine as they are relatively easy to obtain, are characterized by low morbidity, and can differentiate into myogenic progenitor cells. Although studies have elucidated the principal markers, PAX7, Desmin, MyoD, and MHC, the underlying mechanisms are not completely understood. This motivates the application of computational methods to facilitate greater understanding of such processes. In the following, we present a multi-stage kinetic model comprising a system of ordinary differential equations (ODEs). We sought to model ASC differentiation using data from a static culture, where no strain is applied, and a dynamic culture, where 10% strain is applied. The coefficients of the equations have been modulated by those experimental data points. To correctly represent the trajectories, various switches and a feedback factor based on total cell number have been introduced to better represent the biology of ASC differentiation. Furthermore, the model has then been applied to predict ASC fate for strains different from those used in the experimental conditions and for times longer than the duration of the experiment. Analysis of the results reveals unique characteristics of ASC myogenesis under dynamic conditions of the applied strain. 相似文献
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Monica A. Thomas Becky J. Buelow Amanda M. Nevins Stephanie E. Jones Francis C. Peterson Rebekah L. Gundry Mitchell H. Grayson Brian F. Volkman 《The Journal of biological chemistry》2015,290(7):4528-4536
CCL28 is a human chemokine constitutively expressed by epithelial cells in diverse mucosal tissues and is known to attract a variety of immune cell types including T-cell subsets and eosinophils. Elevated levels of CCL28 have been found in the airways of individuals with asthma, and previous studies have indicated that CCL28 plays a vital role in the acute development of post-viral asthma. Our study builds on this, demonstrating that CCL28 is also important in the chronic post-viral asthma phenotype. In the absence of a viral infection, we also demonstrate that CCL28 is both necessary and sufficient for induction of asthma pathology. Additionally, we present the first effort aimed at elucidating the structural features of CCL28. Chemokines are defined by a conserved tertiary structure composed of a three-stranded β-sheet and a C-terminal α-helix constrained by two disulfide bonds. In addition to the four disulfide bond-forming cysteine residues that define the traditional chemokine fold, CCL28 possesses two additional cysteine residues that form a third disulfide bond. If all disulfide bonds are disrupted, recombinant human CCL28 is no longer able to drive mouse CD4+ T-cell chemotaxis or in vivo airway hyper-reactivity, indicating that the conserved chemokine fold is necessary for its biologic activity. Due to the intimate relationship between CCL28 and asthma pathology, it is clear that CCL28 presents a novel target for the development of alternative asthma therapeutics. 相似文献
23.
Tong SY Xie S Richardson LJ Ballard SA Dakh F Grabsch EA Grayson ML Howden BP Johnson PD Giffard PM 《PloS one》2011,6(12):e29189
We have developed a single nucleotide polymorphism (SNP) nucleated high-resolution melting (HRM) technique to genotype Enterococcus faecium. Eight SNPs were derived from the E. faecium multilocus sequence typing (MLST) database and amplified fragments containing these SNPs were interrogated by HRM. We tested the HRM genotyping scheme on 85 E. faecium bloodstream isolates and compared the results with MLST, pulsed-field gel electrophoresis (PFGE) and an allele specific real-time PCR (AS kinetic PCR) SNP typing method. In silico analysis based on predicted HRM curves according to the G+C content of each fragment for all 567 sequence types (STs) in the MLST database together with empiric data from the 85 isolates demonstrated that HRM analysis resolves E. faecium into 231 "melting types" (MelTs) and provides a Simpson's Index of Diversity (D) of 0.991 with respect to MLST. This is a significant improvement on the AS kinetic PCR SNP typing scheme that resolves 61 SNP types with D of 0.95. The MelTs were concordant with the known ST of the isolates. For the 85 isolates, there were 13 PFGE patterns, 17 STs, 14 MelTs and eight SNP types. There was excellent concordance between PFGE, MLST and MelTs with Adjusted Rand Indices of PFGE to MelT 0.936 and ST to MelT 0.973. In conclusion, this HRM based method appears rapid and reproducible. The results are concordant with MLST and the MLST based population structure. 相似文献
24.
Purohit PK Inamdar MM Grayson PD Squires TM Kondev J Phillips R 《Biophysical journal》2005,88(2):851-866
The conjunction of insights from structural biology, solution biochemistry, genetics, and single-molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this article we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure. 相似文献
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Curtis J. Henry Jason M. Grayson Latoya M. Mitchell Marlena M. Westcott Elizabeth M. Hiltbold 《Cellular immunology》2010,264(1):23-31
Listeria monocytogenes infection induces a strong inflammatory response characterized by the production of IL-12 and IFN-γ and protective immunity against this pathogen is dependent on CD8+ T cells (CTL). Recent studies have suggested that these inflammatory cytokines affect the rate of memory CD8+ T cell generation as well as the number of short-lived effector cells generated. The role of the closely related cytokine, IL-23, in this response has not been examined. We hypothesized that IL-12 and IL-23 produced by dendritic cells collectively enhance the generation and function of memory cells. To test this hypothesis, we employed a DC vaccination approach. Mice lacking IL-12 and IL-23 were vaccinated with wild-type (WT), IL-12−/−, or IL-12/23−/− DC and protection to Lm was monitored. Mice vaccinated with WT and IL-12−/− DC were resistant to lethal challenge with Lm. Surprisingly, mice vaccinated with IL-12/23−/− DC exhibited significantly reduced protection when challenged. Protection correlated with the relative size of the memory pools generated. In summary, these data indicate that IL-23 can partially compensate for the lack of IL-12 in the generation protective immunity against Lm. 相似文献
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Background
Burkholderia pseudomallei is a saprophyte in tropical environments and an opportunistic human pathogen. This versatility requires a sensing mechanism that allows the bacterium to respond rapidly to altered environmental conditions. We characterized a two-component signal transduction locus from B. pseudomallei 204, mrgR and mrgS, encoding products with extensive homology with response regulators and histidine protein kinases of Escherichia coli, Bordetella pertussis, and Vibrio cholerae. 相似文献30.