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Updated: Jul 17, 2025

Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes
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Phosphatidylinositol-specific phospholipase C can decrease Müller cell viability and suppress its phagocytic activity

Bianjin Sun1,2, Shudan Lin1,3, Mengmeng Zheng1

  • 1Zhejiang Provincial Key Laboratory for Technology and Application of Model Organisms, Key Laboratory of Laboratory Medicine, Ministry of Education, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, China.

Canadian Journal of Microbiology
|September 6, 2023
PubMed

Insights

Bacillus cereus eye infections are worsened by PI-PLC proteins that reduce Müller cell viability and impair their phagocytic function, hindering bacterial clearance.

Area of Science:

  • Ophthalmology
  • Microbiology
  • Cell Biology

Background:

  • Bacillus cereus endophthalmitis causes rapid blindness via exotoxins.
  • Ocular cell phagocytosis is crucial for combating bacterial eye infections.
  • The role of Bc-phosphatidylinositol-specific phospholipase C (PI-PLC) proteins in B. cereus endophthalmitis pathogenesis was previously unclear.

Purpose of the Study:

  • To investigate the impact of Bc-PI-PLC proteins encoded by plcA-1/2 genes on Müller cells in Bacillus cereus endophthalmitis.
  • To compare the enzymatic activity of Bc-PI-PLC-A1 and Bc-PI-PLC-A2.
  • To elucidate the mechanism by which PI-PLC proteins affect Müller cell viability and phagocytosis.

Main Methods:

  • Enzymatic activity assays for Bc-PI-PLC-A1 and Bc-PI-PLC-A2.
  • Assessment of Müller cell viability following exposure to PI-PLC proteins.
  • Phagocytosis assays using Müller cells and measurement of PI3K/AKT signaling pathway phosphorylation levels.

Main Results:

  • Bc-PI-PLC-A2 exhibited approximately twofold higher enzymatic activity than Bc-PI-PLC-A1.
  • Both Bc-PI-PLC-A1 and Bc-PI-PLC-A2 inhibited Müller cell viability.
  • PI-PLC proteins suppressed Müller cell phagocytosis by downregulating the PI3K/AKT signaling pathway.

Conclusions:

  • PI-PLC proteins from Bacillus cereus inhibit Müller cell viability.
  • PI-PLC proteins impair Müller cell phagocytic capacity, contributing to B. cereus endophthalmitis pathogenesis.
  • These findings offer new insights into the virulence mechanisms of Bacillus cereus in the eye.
Keywords:
Bacillus cereusMüller cellPI-PLC proteinsPI3K–AKT signaling pathwayphagocytosis

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