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Published on: April 6, 2022
Histamine prevents apoptosis in human monocytes.
1Department of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Summary
Histamine prolongs monocyte lifespan by preventing apoptosis through H2R signaling, potentially contributing to chronic allergic diseases like atopic dermatitis (AD). This finding offers new insights into immune cell regulation in inflammatory conditions.
Area of Science:
- Immunology
- Dermatology
Background:
- Chronic atopic dermatitis (AD) involves activated monocytes, crucial for lesion development.
- Histamine, a key mediator of inflammation, has unclear effects on monocyte lifespan.
Purpose of the Study:
- To investigate histamine's effect on human monocyte lifespan in healthy donors and AD patients.
- To elucidate the mechanisms underlying histamine's influence on monocyte apoptosis.
Main Methods:
- Monocyte apoptosis was induced via serum deprivation, CD95/Fas ligation, or dexamethasone.
- Histamine's effects were assessed using annexin V/propidium iodide staining, flow cytometry for Bcl-2 and caspase-3, and analysis of secreted factors.
- The role of the cAMP pathway and histamine receptors (H2R) was investigated.
Main Results:
- Histamine dose- and time-dependently prevented monocyte apoptosis.
- These effects were mediated by H2R signaling and involved up-regulation of Bcl-2/Mcl-1 and inhibition of caspase-3.
- Histamine-induced factors, including IL-10, contributed to prolonged monocyte survival, dependent on the cAMP pathway.
Conclusions:
- Histamine, via H2R signaling, extends monocyte lifespan, promoting their infiltration into inflammatory sites.
- This mechanism may contribute to the pathogenesis of chronic allergic disorders like atopic dermatitis.
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