Immunity system complexity: lipid droplets fight bacteria (Introduction)

by David Turell , Saturday, October 17, 2020, 20:29 (1285 days ago) @ David Turell

They contain fighting proteins:

https://science.sciencemag.org/content/sci/370/6514/eaay8085.full.pdf

"INTRODUCTION: In all eukaryotic cells, lipid droplets (LDs) store and supply essential
lipids to produce signaling molecules, membrane building blocks, and metabolic energy.
The LD monolayer also accommodates proteins not obviously related to lipids, such as
transcription factors, chromatin components, and toxic proteins. Common parasites (such as trypanosomes and Plasmodium falciparum), bacteria (such as mycobacteria and Chlamydia), and viruses (such as hepatitis C and dengue) induce and target LDs during their life cycles. The current view is that LDs support infection, providing microorganisms with substrates for effective growth.

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"ONCLUSION: These results demonstrate that LDs form a first-line intracellular defense.
They act as a molecular switch in innate immunity, responding to danger signals by both
reprogramming cell metabolism and eliciting protein-mediated antimicrobial mechanisms.
Mechanisms of LD trafficking and docking with phagocytic and parasitophorous membranes, observed here and described for several pathogens, may facilitate the delivery of
immune proteins located on the LD surface. Intracellular LDs can provide infected cells with
several biological benefits, serving as a location to attract pathogens as well as coordinating different immune systems that operate simultaneously against different classes of pathogens. LDs may also sequester cytotoxic compounds (such as antimicrobial peptides), reducing damage to other cellular organelles. In view of the widespread resistance to current antibiotics, this study helps decipher molecular mechanisms involved in antimicrobial defense
that could be exploited for development of new anti-infective agents."

Comment: A very clever design protecting a cellular food source. Not by chance. For cells to survive bacterial attack, this system had to designed in place when the cells themselves appeared.