Primary human dermal fibroblasts selectively sense LPS, poly I:C and ADP heptose and initiate immune response mostly through chemokine secretion
- 1Institut Pasteur, Université Paris Cité, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, France
- 2Institut Pasteur, C2RT, UTechS Photonic BioImaging, Paris, France
Abstract
Fibroblasts are considered structural cells that maintain tissue homeostasis and facilitate repair. They also participate in innate immunity, although their pattern recognition capabilities remain incompletely characterized. Here, we systematically assessed the innate immune responses of commercially available primary human dermal fibroblasts from a male and a female donor. Fibroblasts were stimulated with a panel of microbe-associated molecular patterns (MAMPs) targeting various pattern recognition receptors (PRRs), including Toll-like receptors (TLRs), NOD-like receptors (NODs), Alpha kinase 1 (ALPK1) and STING. We quantified innate immune activation by measuring the nuclear translocation of NF-κB via high-content microscopy, and cytokines and chemokines secretion by ELISA. Baseline PRRs expression was determined using quantitative PCR. Only a restricted subset of agonists induced robust NF-κB activation with 30-70% positive cells, specifically E. coli LPS (TLR4), Poly I:C (TLR3/RIG-I), and unexpectedly ADP heptose (ALPK1). Dose-response analysis revealed surprisingly high sensitivity to LPS, as low as 1 ng/mL. Apart from IL-6 and RANTES, which were produced exclusively following Poly I:C stimulation, the secretion of pro-inflammatory cytokines IL-1β, and TNF, as well as the anti-inflammatory cytokines IL-10 and IFN-β remained undetectable compared to that of the chemokines IL-8 and MCP-1. Consistent with this limited reactivity, qPCR of PRRs revealed the basal gene expression of TLR4 co-receptors MD2, CD14, and ALPK1, while most other receptors were expressed at very low or undetectable levels. Notably, NOD1 was highly expressed despite the absence of cell activation with several NOD1 agonists. In conclusion, primary human dermal fibroblasts exhibit a highly selective yet sensitive innate immune response, that is largely restricted to chemokine production. This unexpected dissociation between chemokine and cytokine responses suggests that fibroblasts function as sentinel cells in early skin defence, capable of detecting key microbial patterns at low concentrations, and orchestrating local immune surveillance. Further investigation into interindividual variability and context-dependent activation is required.
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BibTeX
@article{klein2026primary,
title = {{Primary human dermal fibroblasts selectively sense LPS, poly I:C and ADP heptose and initiate immune response mostly through chemokine secretion}},
author = {Julie Klein and Christophe Gallard and Brigitte David-Watine and Catherine Werts},
journal = {Innate Immunity},
year = {2026},
month = sep,
doi = {10.1177/17534259261473360},
url = {https://hal.science/hal-05806050v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Primary human dermal fibroblasts selectively sense LPS, poly I:C and ADP heptose and initiate immune response mostly through chemokine secretion
AU - Julie Klein
AU - Christophe Gallard
AU - Brigitte David-Watine
AU - Catherine Werts
PY - 2026
DA - 2026/09/17
JO - Innate Immunity
DO - 10.1177/17534259261473360
UR - https://hal.science/hal-05806050v1
AB - Fibroblasts are considered structural cells that maintain tissue homeostasis and facilitate repair. They also participate in innate immunity, although their pattern recognition capabilities remain incompletely characterized. Here, we systematically assessed the innate immune responses of commercially available primary human dermal fibroblasts from a male and a female donor. Fibroblasts were stimulated with a panel of microbe-associated molecular patterns (MAMPs) targeting various pattern recognition receptors (PRRs), including Toll-like receptors (TLRs), NOD-like receptors (NODs), Alpha kinase 1 (ALPK1) and STING. We quantified innate immune activation by measuring the nuclear translocation of NF-κB via high-content microscopy, and cytokines and chemokines secretion by ELISA. Baseline PRRs expression was determined using quantitative PCR. Only a restricted subset of agonists induced robust NF-κB activation with 30-70% positive cells, specifically E. coli LPS (TLR4), Poly I:C (TLR3/RIG-I), and unexpectedly ADP heptose (ALPK1). Dose-response analysis revealed surprisingly high sensitivity to LPS, as low as 1 ng/mL. Apart from IL-6 and RANTES, which were produced exclusively following Poly I:C stimulation, the secretion of pro-inflammatory cytokines IL-1β, and TNF, as well as the anti-inflammatory cytokines IL-10 and IFN-β remained undetectable compared to that of the chemokines IL-8 and MCP-1. Consistent with this limited reactivity, qPCR of PRRs revealed the basal gene expression of TLR4 co-receptors MD2, CD14, and ALPK1, while most other receptors were expressed at very low or undetectable levels. Notably, NOD1 was highly expressed despite the absence of cell activation with several NOD1 agonists. In conclusion, primary human dermal fibroblasts exhibit a highly selective yet sensitive innate immune response, that is largely restricted to chemokine production. This unexpected dissociation between chemokine and cytokine responses suggests that fibroblasts function as sentinel cells in early skin defence, capable of detecting key microbial patterns at low concentrations, and orchestrating local immune surveillance. Further investigation into interindividual variability and context-dependent activation is required.
SN - 1753-4259
SN - 1753-4267
ER -