Biology subjects

Kiessling, L. L.

Publications and source records attributed to Kiessling, L. L..

4 recordsLinked to original sources

bioRxiv2022

Antibiotic action revealed by real-time imaging of the mycobacterial membrane

The current understanding of mycobacterial cell envelope remodeling in response to antibiotics is limited. Chemical tools that report on phenotypic changes with minimal cell wall perturbation are critical to understanding such time-dependent processes. We employed a fluorogenic chemical probe to image how antibiotics perturb mycobacterial cell envelope assembly in real-time. Time-lapse microscopy revealed that differential antibiotic treatment elicited unique cellular phenotypes, providing a platform for simultaneously monitoring cell envelope construction and remodeling responses. Our data show that rifampicin, which does not directly inhibit cell wall biosynthesis, affords a readily detected mycomembrane phenotype. The fluorogenic probe revealed the production of extracellular vesicles in response to antibiotics, and analyses of these vesicles indicate that antibiotic treatment elicits the release of agents that attenuate macrophage activation.

microbiology↗

bioRxiv2021

Bifunctional Peptide that Anneals to Damaged Collagen and Clusters TGF-β Receptors Enhances Wound Healing

Transforming growth factor-{beta} (TGF-{beta}) plays important roles in wound healing. The activity of TGF-{beta} is initiated upon binding of the growth factor to extracellular domains of its receptors. We sought to facilitate activation by clustering these extracellular domains. To do so, we used a known peptide that binds to TGF-{beta} receptors without diminishing their affinity for TGF-{beta}. We conjugated this peptide to a collagen-mimetic peptide that can anneal to damaged collagen in a wound bed. We find that the conjugate enhances collagen deposition and wound closure in mice in a manner consistent with the clustering of TGF-{beta} receptors. This strategy provides a means to upregulate the TGF-{beta} signaling pathway without adding exogenous TGF-{beta} and could inspire means to treat severe wounds. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/461420v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@a0c248org.highwire.dtl.DTLVardef@332b3forg.highwire.dtl.DTLVardef@15c3533org.highwire.dtl.DTLVardef@a8b75a_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Discovery of small molecule pathway regulators by image profile matching

Identifying chemical regulators of biological pathways is a time-consuming bottleneck in developing therapeutics and research compounds. Typically, thousands to millions of candidate small molecules are tested in target-based biochemical screens or phenotypic cell-based screens, both expensive experiments customized to each disease. Here, our uncustomized, virtual profile-based screening approach instead identifies compounds that match to pathways based on phenotypic information in public cell image data, created using the Cell Painting assay. Our straightforward correlation-based computational strategy retrospectively uncovered the expected, known small molecule regulators for 32% of positive-control gene queries. In prospective, discovery mode, we efficiently identified new compounds related to three query genes, and validated them in subsequent gene-relevant assays, including compounds that phenocopy or pheno-oppose YAP1 overexpression and kill a Yap1-dependent sarcoma cell line. This image profile-based approach could replace many customized labor- and resource-intensive screens and accelerate the discovery of biologically and therapeutically useful compounds. One sentence summaryIf a genetic perturbation impacts cell morphology, a computational query can reveal compounds whose morphology "matches".

bioinformatics↗

bioRxiv2021

Biosynthetic Glycan Labeling

Glycans are ubiquitous and play important biological roles, yet chemical methods for probing their structure and function within cells remain limited. Strategies for studying other biomacromolecules, such as proteins, often exploit chemoselective reactions for covalent modification, capture, or imaging. Unlike amino acids that constitute proteins, glycan building blocks lack distinguishing reactivity because they are composed primarily of polyol isomers. Moreover, encoding glycan variants through genetic manipulation is complex. Therefore, we formulated a new, generalizable strategy for chemoselective glycan modification that directly takes advantage of cellular glycosyltransferases. Many of these enzymes are selective for the products they generate yet promiscuous in their donor preferences. Thus, we designed reagents with bioorthogonal handles that function as glycosyltransferase substrate surrogates. We validated the feasibility of this approach by synthesizing and testing probes of D-arabinofuranose (D-Araf), a monosaccharide found in bacteria and an essential component of the cell wall that protects mycobacteria, including Mycobacterium tuberculosis. The result is the first probe capable of selectively labeling arabinofuranose-containing glycans. Our studies serve as a platform for developing new chemoselective labeling agents for other privileged monosaccharides. This probe revealed an asymmetric distribution of D-Araf residues during mycobacterial cell growth and could be used to detect mycobacteria in THP1-derived macrophages.

biochemistry↗