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Updated: Jul 18, 2025

Screening Bioactive Nanoparticles in Phagocytic Immune Cells for Inhibitors of Toll-like Receptor Signaling
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TLR2 mediates autophagy through ERK signaling pathway in Chlamydia psittaci CPSIT_p7 protein-stimulated RAW264.7

Ying Luo1,2, Zhenjie Sun1, Qian Chen3

  • 1Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.

Microbiology and Immunology
|August 24, 2023
PubMed

Insights

Chlamydia psittaci protein CPSIT_p7 triggers autophagy in macrophages via Toll-like receptor 2 (TLR2) and the extracellular regulated protein kinase (ERK) pathway. This study reveals key molecular mechanisms of macrophage defense against this zoonotic pathogen.

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • Chlamydia psittaci is a zoonotic pathogen affecting birds and humans.
  • Macrophages are crucial for innate immunity against C. psittaci, but underlying mechanisms are unclear.

Purpose of the Study:

  • Investigate the role of C. psittaci plasmid protein CPSIT_p7 in regulating autophagy in RAW264.7 cells.
  • Elucidate the molecular pathways involved in CPSIT_p7-induced autophagy.

Main Methods:

  • Stimulation of RAW264.7 cells with C. psittaci plasmid protein CPSIT_p7.
  • Analysis of autophagy markers (LC3, Beclin1) and signaling pathways (ERK, JNK, p38, Akt).
  • siRNA knockdown of Toll-like receptor 2 (TLR2) and use of ERK inhibitor (PD98059).

Main Results:

  • CPSIT_p7 induced autophagy markers LC3 and Beclin1 expression.
  • CPSIT_p7 increased phosphorylation of ERK, JNK, p38, and Akt.
  • TLR2 knockdown significantly downregulated CPSIT_p7-induced autophagy.
  • ERK inhibition reduced autophagy in CPSIT_p7-stimulated macrophages.

Conclusions:

  • TLR2 is essential for CPSIT_p7-induced autophagy in macrophages.
  • The ERK signaling pathway mediates CPSIT_p7-induced autophagy.
  • These findings reveal molecular mechanisms of macrophage defense against C. psittaci.
Keywords:
CPSIT_p7Chlamydia psittaciMAPKRAW264.7 cellsautophagy

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