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Coordinated Regulation of TLR2 Signaling by Neu1 Sialidase and the Siglec-5/Siglec-14 Receptor Pair During Mycoplasma pneumoniae Infection

delete2026-06-25
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PRE
AI
H
Haodang Luo
Q
Qianrui Zeng
N
Na Xie
C
Chi Zhang
C
Chang Liu
S
Shutong Chen
C
Caihong Yan
C
Chun Li
H
Haiying Wu
J
Jun He
Y
Yanhua Zeng *
X
Xiaoxing You *
DOI:10.1021/acsinfecdis.5c01129delete
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Abstract

Abstract

En 中文
Mycoplasma pneumoniae is a primary cause of community-acquired pneumonia, characterized by an excessive host inflammatory response that often drives lung pathology. While Toll-like receptor 2 (TLR2) is the principal sensor for this pathogen, the regulatory mechanisms that calibrate its signaling intensity remain incompletely understood. In this study, we delineate a novel disinhibition-amplification network controlling the macrophage response to M. pneumoniae. We demonstrate that TLR2 engagement triggers the secretion of Matrix metalloproteinase-9 (MMP-9), which subsequently activates the host sialidase Neu1. Activated Neu1 translocates to the cell surface and disrupts the constitutive inhibitory interaction between Siglec-5 and TLR2, effectively releasing a molecular brake. Concurrently, infection induces the specific upregulation of the activating receptor Siglec-14. We reveal that Siglec-14 physically interacts with TLR2 and recruits the Spleen Tyrosine Kinase (Syk) to the plasma membrane. Crucially, this Siglec-14/Syk axis functions as a necessary molecular scaffold that amplifies and sustains MAPK and NF-κB signaling. Disruption of this network, either by silencing Neu1 or Siglec-14, significantly attenuates the inflammatory response. These findings identify the Siglec-5/Siglec-14 receptor pair as a critical checkpoint in mycoplasma pathogenesis and suggest that targeting the MMP9-Neu1-Siglec-14 axis offers a new therapeutic strategy to mitigate inflammation-mediated lung damage.
Keywords:
Immunology
Infectious diseases
Inflammation
Peptides and proteins
Receptors
Mycoplasma pneumoniae
Siglec-14
Siglec-5
Matrix metalloproteinase-9
Spleen tyrosine kinase

Journal

ACS Infectious Diseases cover
ACS Infectious Diseases
IF:
3.8
Papers:
2.4K
Citations:
6.9K

Organization

U
University of South China
Scholars:
3.4K
Papers: 962
Citations: 1.0W
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