Biology subjects

Herold, K.

Publications and source records attributed to Herold, K..

3 recordsLinked to original sources

bioRxiv2021

Toll-like receptor 5 as a novel receptor for fungal zymosan

Microbial pathogens carry specific structural patterns which were termed pathogen-associated molecular patterns (PAMPs). Toll-like receptors (TLRs) as key elements for the recognition of microbial pathogens are necessary for the activation of innate immune pathways. TLRs are activated by binding PAMPs of bacteria, viruses and fungi and initiate a signaling pathway resulting in the activation of transcription factors which modulate the production of various proinflammatory cytokines. It is not fully clear in detail which microbial pattern is recognized by which TLR. Here we show for the first time that TLR5 is a strong receptor for the yeast particle zymosan. We have generated stable human cell lines with combinations of TLR2 and TLR5 knock in/knock out together with stable nuclear factor kappaB (NF-{kappa}B) luciferase reporters. We found that both receptors TLR5 and TLR2 lead to an independent activation of the NF-{kappa}B pathway when simulated with zymosan. Our results demonstrate that TLR5 is a receptor for the fungal particle zymosan in addition to bacterial fragments like flagellin. Distinct cytokine patterns might suggest that TLR5 is potentially important for the differentiation in the recognition of the specific type of the foreign microorganisms and in the specific host defense response.

immunology↗

bioRxiv2019

High-content interrogation of human induced pluripotent stem cell-derived cortical organoid platforms.

The need for scalable and high-throughput approaches to screening using 3D human stem cell models remains a central challenge in using stem cell disease models for drug discovery. It is imperative to develop standardized systems for phenotypic screening, yet most researchers screen cells across different platforms using a multitude of assays. In this study, we have developed a workflow centered on a small array of assays that can be employed to screen 3D stem cell cultures across a set of platforms. This workflow can be used as a starting point for a standardized approach to phenotypic screening. In this manuscript we hope to provide a roadmap for groups looking to start high-content screening using 3D organoid systems. To do this, we employ serum-free embryoid bodies (SFEBs) created from human induced pluripotent stem cells (hiPSCs). SFEBs are used in this study because they do not display the same level of heterogeneity observed in other neural organoid systems and they are amenable to high content imaging without cryosectioning. They contain populations of excitatory and inhibitory neurons that form synaptically active networks1 and medium- to high-throughput electrophysiology can be performed using SFEBs via the multielectrode array (MEA). The assays outlined in this study allow SFEBs to be scanned for neurite outgrowth, cell number and electrophysiological activity. SFEBs derived from control and disease hiPSCs can be used in combination with high-throughput screening assays to generate sufficient statistical power to compensate for the biological and experimental variability common in 3D cultures, while significantly decreasing processing speed, thus making this an efficient starting point for phenotypic drug screening.

neuroscience↗

bioRxiv2019

Inhibition of A20 deubiquitinase activity by KSHV vFLIP: A SUMO dependent mechanism?

KSHV viral FLICE inhibitory protein (vFLIP) is a potent activator of NF-{kappa}B signaling and an inhibitor of apoptosis and autophagy. Inhibition of vFLIP function and NF-{kappa}B signaling promotes lytic reactivation. Here we provide evidence for a novel function of vFLIP in promoting NF{kappa}B signaling through inhibition of the DUB activity of the negative regulator, A20. We demonstrate interaction of vFLIP with the Itch/A20 ubiquitin editing complex. We have identified a SUMO interaction motif in vFLIP that is required for NF-{kappa}B activation. Mutation of the SIM in BAC16 resulted in increased spontaneous RTA expression and loss of spindle cell morphology. Our results suggest a role for SUMO in mediating vFLIP function and provide evidence for vFLIP modulation of the negative regulation of NF-{kappa}B signaling by A20. Our results provide further insight into the function of vFLIP and SUMO in the regulation of NF-{kappa}B signaling and the latent lytic transition.

microbiology↗