Holtvinson0215

Stem cells are widely explored in regenerative medicine as a source to produce diverse cell types. Despite the wide usage of stem cells like mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs), there is a lack of robust methods to rapidly discern the phenotypic and functional heterogeneity of stem cells. The organization of actin cytoskeleton has been previously used to discern divergent stem cell differentiation pathways. In this paper, we highlight the versatility of a cell profiling method for actin turnover dynamics. Actin filaments in live stem cells are labeled using SiR-actin, a cell permeable fluorogenic probe, to determine the endogenous actin turnover. Live MSC imaging after days of induction successfully demonstrated lineage specific change in actin turnover. Next, we highlighted the differences in the cellular heterogeneity of actin dynamics during adipogenic or osteogenic MSC differentiation. Next, we applied the method to differentiating iPSCs in culture, and detected a progressive slowdown in actin turnover during differentiation upon stimulation with neural or cardiac media. Androgen Receptor Antagonist mouse Finally, as a proof of concept, the actin dynamic profiling was used to isolate MSCs via flow cytometry prior to sorting into three distinct sub-populations with low, intermediate or high actin dynamics. A greater fraction of MSCs with more rapid actin dynamics demonstrated increased inclination for adipogenesis, whereas, slower actin dynamics correlated with increased osteogenesis. Together, these results show that actin turnover can serve as a versatile biomarker to not only track cellular phenotypic heterogeneity but also harvest live cells with potential for differential phenotypic fates.Physiologically-based toxicokinetic (PBTK) models are important tools for in vitro to in vivo or inter-species extrapolations in health risk assessment of foodborne and non-foodborne chemicals. Here we present a generic PBTK model implemented in the EuroMix toolbox, MCRA 9 and predict internal kinetics of nine chemicals (three endocrine disrupters, three liver steatosis inducers, and three developmental toxicants), in data-rich and data-poor conditions, when increasingly complex levels of parametrization are applied. At the first stage, only QSAR models were used to determine substance-specific parameters, then some parameter values were refined by estimates from substance-specific or high-throughput in vitro experiments. At the last stage, elimination or absorption parameters were calibrated based on available in vivo kinetic data. The results illustrate that parametrization plays a capital role in the output of the PBTK model, as it can change how chemicals are prioritized based on internal concentration factors. In data-poor situations, estimates can be far from observed values. In many cases of chronic exposure, the PBTK model can be summarized by an external to internal dose factor, and interspecies concentration factors can be used to perform interspecies extrapolation. We finally discuss the implementation and use of the model in the MCRA risk assessment platform.Oral delivery of poorly water-soluble drugs (PWSDs), which predominate the development pipeline, poses significant challenges. Weakly basic compounds, such as atazanavir, represent a critical class of PWSDs as even the administration of the crystalline solid may invoke supersaturation during gastric-intestinal transfer. The absorption advantage afforded by this supersaturated state can be offset by inherent metastability and a tendency to revert to the lower energy crystalline state. Therefore, it is important to understand the physiological factors that can affect crystallization to improve in vitro-in vivo predictiveness and to regulate inter-individual responses. The first aim of this study was to elucidate the influence of lyso-phosphatidylcholine (lyso-PC) and sodium oleate on crystallization, as the products of phosphatidylcholine (PC) hydrolysis and the major lipid components of human intestinal fluid (HIF) and updated fasted state simulated intestinal fluid version 3 (FaSSIF-V3). Secondly, as an indivle salt fraction when designing a biorelevant medium for supersaturating formulations. In vivo, inter-individual differences in the amount and types of bile acids and phospholipids present may influence the behaviour of supersaturating formulations.Purpose Membrane engineering has versatile applications in adoptive cell therapies, immune therapy or drug delivery. Incorporation of lipidated antibody-derived ligands into cells may enforce supraphysiological cell interactions that offer new therapeutic approaches. A challenge is the defined synthesis of lipidated ligands that effectively interact with such membranes. Methods Sortase-A was used to attach a PEGylated, dimyristyl lipid-anchor on single-domain antibodies (VHH). The membrane insertion was investigated on liposomal bilayers, myeloid-derived suppressor cells (MDSC) and T cells. Results The lipidated VHHs remodeled liposomal as well as cellular membranes. The VHH carrying liposomes were successfully targeted towards antigen-positive cells. MDSC and Tcells were both modified with lipidated VHHs as detected with an FITC-anti-llama antibody. Tcells that carried an anti-CD11b VHH showed cellular association in vitro with CD11b+Gr-1+ MDSC in a two-dimensional magnetic activated cell sorting / flow-cytometry assay. Conclusion The applied combination of chemoenzymatic ligation, PEGylated lipid anchors and single-domain antibodies delivers water-soluble and chemically defined lipidated ligands, which readily associate with liposomal and cellular membranes. This enables liposomal drug targeting and artificial cell-cell interactions. Hence, the presented concept for lipidation of single-domain antibodies is promising for further application in the field of drug delivery or cell-based therapies.Wound healing is a complex and costly public health problem that should be timely addressed to achieve a rapid and adequate tissue repair avoiding or even eliminating potential pathogenic infection. Chronic infected non-healing wounds represent a serious concern for health care systems. Efficient wound dressings with tailored therapy having the best response and highest safety margin for the management of chronic non-healing wounds are still needed. The use of novel wound dressing materials has emerged as a promising tool to fulfil these requirements. In this work, asymmetric electrospun polycaprolactone (PCL)-based nanofibers (NFs) were decorated with electrosprayed poly(lactic-co-glycolic acid) microparticles (PLGA MPs) containing the natural antibacterial compound thymol (THY) in order to obtain drug eluting antimicrobial dressings having sustained release. The synthesized dressings successfully inhibited the in vitro growth of Staphylococcus aureus ATCC 25923, showing also at the same doses cytocompatibility on human dermal fibroblasts and keratinocyte cultures after treatment for 24 h, which was not observed when using free thymol.