Skin and hair on-a-chip: in vitro skin models versus ex vivo tissue maintenance with dynamic perfusion

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Substantial progress has been achieved over the last few decades in the development of skin equivalents to model the skin as an organ. However, their static culture still limits the emulation of essential physiological properties crucial for toxicity testing and compound screening. Here, we describe a dynamically perfused chip-based bioreactor platform capable of applying variable mechanical shear stress and extending culture periods. This leads to improvements of culture conditions for integrated in vitro skin models, ex vivo skin organ cultures and biopsies of single hair follicular units.BMBF, 0315569, GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im ChipformatDFG, GSC 203, Berlin-Brandenburg School for Regenerative Therapie

Aktuelle Trends bei der in vitro-Substanztestung in Deutschland und in der Schweiz

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch

Human hair follicle eqivalents in vitro for transplantation and chip-based substance testing : From 22nd European Society for Animal Cell Technology (ESACT) Meeting on Cell Based Technologies Vienna, Austria. 15-18 May 2011

First published by BioMed Central: Marx, Uwe ; Lindner, Gerd ; Wagner, Ilka ; Horland, Reyk ; Atac, Beren ; Hoffmann, Silke ; Gruchow, Mathias ; Sonntag, Frank ; Klotzbach, Udo ; Lauster, Roland: Human hair follicle equivalents in vitro for transplantation and chip-based substance testing : From 22nd European Society for Animal Cell Technology (ESACT) Meeting on Cell Based Technologies Vienna, Austria. 15-18 May 2011. - In: BMC Proceedings. - ISSN 1753-6561 (online). - 5 (2011), suppl. 8, O7. - doi:10.1186/1753-6561-5-S8-O7

Small RNAs Establish Delays and Temporal Thresholds in Gene Expression

Non-coding RNAs are crucial regulators of gene expression in prokaryotes and eukaryotes, but it remains poorly understood how they affect the dynamics of transcriptional networks. We analyzed the temporal characteristics of the cyanobacterial iron stress response by mathematical modeling and quantitative experimental analyses, and focused on the role of a recently discovered small non-coding RNA, IsrR. We found that IsrR is responsible for a pronounced delay in the accumulation of isiA mRNA encoding the late-phase stress protein, IsiA, and that it ensures a rapid decline in isiA levels once external stress triggers are removed. These kinetic properties allow the system to selectively respond to sustained (as opposed to transient) stimuli, and thus establish a temporal threshold, which prevents energetically costly IsiA accumulation under short-term stress conditions. Biological information is frequently encoded in the quantitative aspects of intracellular signals (e.g., amplitude and duration). Our simulations reveal that competitive inhibition and regulated degradation allow intracellular regulatory networks to efficiently discriminate between transient and sustained inputs

Dynamic culture of human liver equivalents inside a micro-bioreactor for long-term substance testing : From 23rd European Society for Animal Cell Technology (ESACT) Meeting: Better Cells for Better Health Lille, France. 23-26 June 2013

Published by BioMed Central: Materne, Eva-Maria et al.: Dynamic culture of human liver equivalents inside a micro-bioreactor for longterm substance testing. - In: BMC Proceedings. - ISSN 1753-6561 (online). - 7 (2012), suppl. 6, art. P72. - doi:10.1186/1753-6561-7-S6-P72

A dynamic multi-organ-chip for long-term cultivation and substance testing proven by 3D human liver and skin tissue co-culture

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Current in vitro and animal tests for drug development are failing to emulate the systemic organ complexity of the human body and, therefore, to accurately predict drug toxicity. In this study, we present a multi-organ-chip capable of maintaining 3D tissues derived from cell lines, primary cells and biopsies of various human organs. We designed a multi-organ-chip with co-cultures of human artificial liver microtissues and skin biopsies, each a 1/100 000 of the biomass of their original human organ counterparts, and have successfully proven its long-term performance. The system supports two different culture modes: i) tissue exposed to the fluid flow, or ii) tissue shielded from the underlying fluid flow by standard Transwell® cultures. Crosstalk between the two tissues was observed in 14-day co-cultures exposed to fluid flow. Applying the same culture mode, liver microtissues showed sensitivity at different molecular levels to the toxic substance troglitazone during a 6-day exposure. Finally, an astonishingly stable long-term performance of the Transwell®-based co-cultures could be observed over a 28-day period. This mode facilitates exposure of skin at the air–liquid interface. Thus, we provide here a potential new tool for systemic substance testing.BMBF, 0315569, GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im Chipforma

A red tide in the pack ice of the Arctic Ocean

Source at https://doi.org/10.1038/s41598-019-45935-0. In the Arctic Ocean ice algae constitute a key ecosystem component and the ice algal spring bloom a critical event in the annual production cycle. The bulk of ice algal biomass is usually found in the bottom few cm of the sea ice and dominated by pennate diatoms attached to the ice matrix. Here we report a red tide of the phototrophic ciliate Mesodinium rubrum located at the ice-water interface of newly formed pack ice of the high Arctic in early spring. These planktonic ciliates are not able to attach to the ice. Based on observations and theory of fluid dynamics, we propose that convection caused by brine rejection in growing sea ice enabled M. rubrum to bloom at the ice-water interface despite the relative flow between water and ice. We argue that red tides of M. rubrum are more likely to occur under the thinning Arctic sea ice regime

Tapping the nucleotide pool of the host: novel nucleotide carrier proteins of Protochlamydia amoebophila

Protochlamydia amoebophila UWE25 is related to the Chlamydiaceae comprising major pathogens of humans, but thrives as obligate intracellular symbiont in the protozoan host Acanthamoeba sp. The genome of P. amoebophila encodes five paralogous carrier proteins belonging to the nucleotide transporter (NTT) family. Here we report on three P. amoebophila NTT isoforms, PamNTT2, PamNTT3 and PamNTT5, which possess several conserved amino acid residues known to be critical for nucleotide transport. We demonstrated that these carrier proteins are able to transport nucleotides, although substrate specificities and mode of transport differ in an unexpected manner and are unique among known NTTs. PamNTT2 is a counter exchange transporter exhibiting submillimolar apparent affinities for all four RNA nucleotides, PamNTT3 catalyses an unidirectional proton-coupled transport confined to UTP, whereas PamNTT5 mediates a proton-energized GTP and ATP import. All NTT genes of P. amoebophila are transcribed during intracellular multiplication in acanthamoebae. The biochemical characterization of all five NTT proteins from P. amoebophila in this and previous studies uncovered that these metabolically impaired bacteria are intimately connected with their host cell’s metabolism in a surprisingly complex manner