| 1. |
- Ernst, Chantal, et al.
(author)
-
Direct Salmonella injection into enteroid cells allows the study of host-pathogen interactions in the cytosol with high spatiotemporal resolution
- 2024
-
In: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 22:4
-
Journal article (peer-reviewed)abstract
- Intestinal epithelial cells (IECs) play pivotal roles in nutrient uptake and in the protection against gut microorganisms. However, certain enteric pathogens, such as Salmonella enterica serovar Typhimurium (S. Tm), can invade IECs by employing flagella and type III secretion systems (T3SSs) with cognate effector proteins and exploit IECs as a replicative niche. Detection of flagella or T3SS proteins by IECs results in rapid host cell responses, i.e., the activation of inflammasomes. Here, we introduce a single-cell manipulation technology based on fluidic force microscopy (FluidFM) that enables direct bacteria delivery into the cytosol of single IECs within a murine enteroid monolayer. This approach allows to specifically study pathogen-host cell interactions in the cytosol uncoupled from preceding events such as docking, initiation of uptake, or vacuole escape. Consistent with current understanding, we show using a live-cell inflammasome reporter that exposure of the IEC cytosol to S. Tm induces NAIP/NLRC4 inflammasomes via its known ligands flagellin and T3SS rod and needle. Injected S. Tm mutants devoid of these invasion-relevant ligands were able to grow in the cytosol of IECs despite the absence of T3SS functions, suggesting that, in the absence of NAIP/NLRC4 inflammasome activation and the ensuing cell death, no effector-mediated host cell manipulation is required to render the epithelial cytosol growth-permissive for S. Tm. Overall, the experimental system to introduce S. Tm into single enteroid cells enables investigations into the molecular basis governing host-pathogen interactions in the cytosol with high spatiotemporal resolution.
|
|
| 2. |
- Michelle Grandin, H., et al.
(author)
-
Bioinspired, nanoscale approaches in contemporary bioanalytics (Review)
- 2018
-
In: Biointerphases. - : American Vacuum Society. - 1559-4106 .- 1934-8630. ; 13:4
-
Journal article (peer-reviewed)abstract
- The genesis for this topical review stems from the interdisciplinary Biointerfaces International conference 2016 (BI 2016) in Zurich, Switzerland, wherein the need for advances in analytical tools was both expressed and addressed. Pushing the limits of detection for characterizing individual components, such as single proteins, single drug-delivery vehicles, or probing single living cells in a more natural environment, will contribute to the understanding of the complex biomolecular systems central to a number of applications including medical diagnostics, tissue engineering, and drug screening and delivery. Accordingly, the authors begin with an overview of single nanoparticle analytics highlighting two emerging techniques and how they compare with existing techniques. The first is based on single particle tracking of nanoparticles tethered to a mobile supported lipid bilayer, enabling the simultaneous characterization of both size and composition of individual nanoparticles. The second technique is based on probing variations in the ionic conduction across nanoscale apertures for detection of not only nanoparticles but also membrane-tethered proteins, thereby allowing a multiparameter characterization of individual nanoscopic objects, addressing their size, shape, charge, and dipole moment. Subsequently, the authors lead into an example of an area of application that stands to benefit from such advances in bioanalytics, namely, the development of biomimetic lipid- and polymer-based assemblies as stimuli-responsive artificial organelles and nanocarriers designed to optimize delivery of next generation high-molecular-weight biological drugs. This in turn motivates the need for additional advanced techniques for investigating the cellular response to drug delivery, and so the review returns again to bioanalytics, in this case single-cell analysis, while highlighting a technique capable of probing and manipulating the content of individual living cells via fluidic force microscopy. In presenting a concerted movement in the field of bioinspired bioanalytics, positioned in the context of drug delivery, while also noting the critical role of surface modifications, it is the authors’ aim to evaluate progress in the field of single component bioanalytics and to emphasize the impact of initiating and maintaining a fruitful dialogue among scientists, together with clinicians and industry, to guide future directions in this area and to steer innovation to successful translation.
|
|
