Selection and Validation of Reference Genes for Gene Expression Studies in an Equine Adipose-Derived Mesenchymal Stem Cell Differentiation Model by Proteome Analysis and Reverse-Transcriptase Quantitative Real-Time PCR.

Adipose-derived stem cells (ADSCs) are used in tissue regeneration therapies. The objective of this study is to identify stable reference genes (RGs) for use in gene expression studies in a characterized equine adipose-derived mesenchymal stem cell (EADMSC) differentiation model. ADSCs were differentiated into adipocytes (ADs) or osteoblasts (OBs), and the proteomes from these cells were analyzed by liquid chromatography tandem mass spectrometry. Proteins that were stably expressed in all three cells types were identified, and the mRNA expression stabilities for their corresponding genes were validated by RT-qPCR. PPP6R1, CCDC97, and then either ACTB or EPHA2 demonstrated the most stable mRNA levels. Normalizing target gene Cq data with at least three of these RGs simultaneously, as per MIQE guidelines (PPP6R1 and CCDC97 with either ACTB or EPHA2), resulted in congruent conclusions. FABP5 expression was increased in ADs (5.99 and 8.00 fold, p = 0.00002 and p = 0.0003) and in OBs (5.18 and 5.91 fold, p = 0.0011 and p = 0.0023) relative to ADSCs. RUNX2 expression was slightly higher in ADs relative to ADSCs (1.97 and 2.65 fold, p = 0.04 and p = 0.01), but not in OBs (0.9 and 1.03 fold, p = 0.58 and p = 0.91).

Heat Shock Alters the Proteomic Profile of Equine Mesenchymal Stem Cells.

The aim of this research was to determine the impact of heat stress on cell differentiation in an equine mesenchymal stem cell model (EMSC) through the application of heat stress to primary EMSCs as they progressed through the cell specialization process. A proteomic analysis was performed using mass spectrometry to compare relative protein abundances among the proteomes of three cell types: progenitor EMSCs and differentiated osteoblasts and adipocytes, maintained at 37 °C and 42 °C during the process of cell differentiation. A cell-type and temperature-specific response to heat stress was observed, and many of the specific differentially expressed proteins were involved in cell-signaling pathways such as Notch and Wnt signaling, which are known to regulate cellular development. Furthermore, cytoskeletal proteins profilin, DSTN, SPECC1, and DAAM2 showed increased protein levels in osteoblasts differentiated at 42 °C as compared with 37 °C, and these cells, while they appeared to accumulate calcium, did not organize into a whorl agglomerate as is typically seen at physiological temperatures. This altered proteome composition observed suggests that heat stress could have long-term impacts on cellular development. We propose that this in vitro stem cell culture model of cell differentiation is useful for investigating molecular mechanisms that impact cell development in response to stressors.

Probing linker design in citric acid-ciprofloxacin conjugates.

A series of structurally related citric acid-ciprofloxacin conjugates was synthesised to investigate the influence of the linker between citric acid and ciprofloxacin on antibacterial activities. Minimum inhibitory concentrations (MICs) were determined against a panel of reference strains and clinical isolates of bacteria associated with infection in humans and correlated with the DNA gyrase inhibitory activity. The observed trend was rationalised by computational modelling.

The putative small terminase from the thermophilic dsDNA bacteriophage G20C is a nine-subunit oligomer.

The assembly of double-stranded DNA bacteriophages is dependent on a small terminase protein that normally plays two important roles. Firstly, the small terminase protein specifically recognizes viral DNA and recruits the large terminase protein, which makes the initial cut in the dsDNA. Secondly, once the complex of the small terminase, the large terminase and the DNA has docked to the portal protein, and DNA translocation into a preformed empty procapsid has begun, the small terminase modulates the ATPase activity of the large terminase. Here, the putative small terminase protein from the thermostable bacteriophage G20C, which infects the Gram-negative eubacterium Thermus thermophilus, has been produced, purified and crystallized. Size-exclusion chromatography-multi-angle laser light scattering data indicate that the protein forms oligomers containing nine subunits. Crystals diffracting to 2.8 Å resolution have been obtained. These belonged to space group P212121, with unit-cell parameters a = 94.31, b = 125.6, c = 162.8 Å. The self-rotation function and Matthews coefficient calculations are consistent with the presence of a nine-subunit oligomer in the asymmetric unit.