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Updated: Sep 11, 2025
Development and Functional Characterization of Murine Tolerogenic Dendritic Cells
Published on: May 18, 2018
Dermal fibroblast cultures recapitulate differences between deermice and mice in responses to a Toll-like receptor
Jonathan V Duong1, Aqsa Motiwala1, William J Hotz1
1Department of Microbiology and Molecular Genetics, School of Medicine, University of California Irvine, Irvine, CA, United States.
Abstract:
The white-footed deermouse Peromyscus leucopus is a primary reservoir for the agents of Lyme disease and other zoonoses in North America and manifests infection tolerance for the bacteria, protozoa, and viruses it hosts. In previous in vivo studies P. leucopus and M. musculus differed in the degree of sickness and profiles of biomarkers after exposure to bacterial lipopolysaccharide, a TLR4 agonist. As an approach for assessing immunity of mammals in nature and for longitudinal studies of colony animals in the laboratory, we evaluated using bulk and single cell RNA-seq primary dermal fibroblast cultures of P. leucopus and M. musculus in their short-term responses to a TLR2 agonist lipopeptide. By single cell RNA-seq cultures of both species comprised at least two types of fibroblasts, which were further differentiated in their responses to TLR agonists. With continued passage the mouse cell population lost viability, while the deermouse cell population spontaneously transformed into a cell line stably maintained under standard conditions. Bulk RNA-seq revealed distinctive profiles for deermouse and mouse cells in arginine metabolism gene expression, high baseline transcription of the antioxidant transcription factor Nfe2l2 (Nrf2) in deermouse fibroblasts, and the transcription of the aging-associated cytokine interleukin-11 in agonist-treated mouse fibroblasts but not deermouse fibroblasts. In both species' cultures there was increased transcription of several types of endogenous retrovirus (ERV) and transposable elements (TE) after exposure to the agonist. The transcribed ERV/TE sequences in M. musculus cells were generally longer in length and with greater potential for translation than sequences in treated P. leucopus cells. The results indicate feasibility of this in vitro model for both laboratory- and field-based studies and that inherent differences between deermice and mice in cell-autonomous innate immune responses and ERV/TE activation can be demonstrated in dermal fibroblasts as well as the animals themselves.
Insights
White-footed deermice fibroblasts offer a stable cell line for studying innate immunity and zoonotic disease reservoirs. This research highlights distinct cellular responses to immune agonists, revealing differences in gene expression and endogenous retrovirus activation between deermice and mice.
Area of Science:
- Immunology
- Cell Biology
- Zoonotic Diseases
- Comparative Genomics
Background:
- The white-footed deermouse (Peromyscus leucopus) is a key reservoir for Lyme disease and other zoonoses in North America.
- Previous studies showed differing responses to lipopolysaccharide (LPS), a Toll-like receptor 4 (TLR4) agonist, between P. leucopus and Mus musculus.
- Developing in vitro models is crucial for studying mammalian immunity in both natural and laboratory settings.
Purpose of the Study:
- To evaluate primary dermal fibroblast cultures of P. leucopus and M. musculus for studying innate immune responses.
- To assess short-term cellular responses to a Toll-like receptor 2 (TLR2) agonist, lipopeptide.
- To establish a feasible in vitro model for laboratory and field-based immunological studies.
Main Methods:
- Primary dermal fibroblast cultures from P. leucopus and M. musculus were established.
- Bulk and single-cell RNA sequencing (RNA-seq) were employed to analyze cellular responses.
- Cells were exposed to a TLR2 agonist (lipopeptide) to stimulate innate immune pathways.
Main Results:
- Single-cell RNA-seq identified distinct fibroblast subtypes with differential responses to TLR agonists.
- P. leucopus fibroblasts transformed into a stable cell line, unlike M. musculus fibroblasts which lost viability.
- Distinct gene expression profiles were observed, including differences in arginine metabolism, Nrf2 (antioxidant response), and aging-associated cytokines (IL-11).
- Both species showed increased transcription of endogenous retroviruses (ERVs) and transposable elements (TEs) upon agonist stimulation, with M. musculus exhibiting longer and more translatable sequences.
Conclusions:
- Primary dermal fibroblast cultures provide a feasible in vitro model for studying mammalian innate immunity.
- Significant inherent differences exist between P. leucopus and M. musculus in cell-autonomous innate immune responses and ERV/TE activation.
- These cellular differences observed in vitro mirror those seen in vivo, validating the model for future research on zoonotic disease reservoirs.
