Related Experiment Video
Updated: Aug 5, 2026
09:51
Screening Bioactive Nanoparticles in Phagocytic Immune Cells for Inhibitors of Toll-like Receptor Signaling
Published on: July 26, 2017
Synthetic Toll-Like Receptors for Control of Innate Immunity With Far-Red Light
Anna V Leopold1, Vladislav V Verkhusha1,2
1Department of Anatomy, Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
|July 27, 2026
Summary
Scientists engineered Toll-like receptors (TLRs) for optical control using far-red light. This optogenetic system enables precise regulation of innate immunity and cell death pathways via light.
Area of Science:
- Immunology
- Optogenetics
- Molecular Biology
Background:
- Toll-like receptors (TLRs) are key innate immune sensors recognizing microbial patterns.
- TLRs activate signaling pathways like MyD88, NF-κB, and IRF3/IRF7, leading to cytokine production.
- Current methods lack precise temporal and spatial control over TLR-mediated responses.
Purpose of the Study:
- To develop an optogenetic system for light-inducible control of TLR signaling.
- To engineer chimeric TLRs responsive to far-red light.
- To demonstrate light-dependent activation of innate immune and cell death pathways.
Main Methods:
- Replaced extracellular domains of TLR3, TLR4, and TLR5 with a bacterial phytochrome photosensor (DrBphP).
- Created chimeric receptors for far-red light-dependent activation of NF-κB and IRF3/IRF7 pathways.
- Reprogrammed the MyD88 pathway to induce caspase activation instead of cytokine production.
Main Results:
- Chimeric TLRs activated NF-κB and IRF3/IRF7 pathways in mammalian cells upon far-red light exposure.
- The system demonstrated light-dependent induction of caspase activation, linking TLR stimulation to cell death.
- Established a synthetic optogenetic platform for precise control of innate immunity.
Conclusions:
- Optogenetic engineering of TLRs provides a novel method for external control of immune signaling.
- Far-red light activation of chimeric TLRs offers spatiotemporal precision in modulating innate immunity and cell death.
- This platform has potential applications in immunology research and therapeutic strategies.
Related Concept Videos
01:25Cell Signaling in Plants
Plant cells communicate to coordinate their cycle of growth, flowering and fruiting, and activities in roots, shoots, and leaves in response to the changing environmental conditions. Plant signaling is distinct from animal signaling. Plants primarily utilize enzyme-linked receptors, whereas the largest class of cell-surface receptors in animals are G-protein coupled receptors (GPCRs). Unlike animals, receptor tyrosine kinases are rare in plants. Instead, plants have a diverse class of...
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
01:16Transduction
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
02:26NF-κB-dependent Signaling Pathway
The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...