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Published on: December 18, 2010
Podoplanin Antibody SZ168 Alleviates Sepsis Inflammation and Macrophage Dysregulation via ERK Signaling
Hongbin Wang1,2, Junfeng Heng3, Yuhong Zhang4
1Department of Emergency, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China, sdfyy.cn.
Background:
Sepsis is a life-threatening condition marked by excessive inflammation and immune dysregulation. Macrophages are central to this process. Podoplanin (PDPN), a transmembrane glycoprotein, is upregulated in inflammatory macrophages, but its role in sepsis remains unclear.
Objective:
The aim of this study is to investigate the role of PDPN and the therapeutic potential of its monoclonal antibody SZ168 in LPS-induced macrophages and to extend these observations with supplementary in vivo and preliminary clinical validation.
Methods:
RAW264.7 macrophages were stimulated with LPS and treated with SZ168. PDPN expression and the effects of SZ168 on cytokine secretion, polarization, apoptosis, and ERK signaling were assessed by proteomics, qPCR, Western blotting, ELISA, and flow cytometry. siRNA-mediated PDPN knockdown was used to validate pathway dependence. During revision, additional Western blot validation of MEK, p90RSK, and c-Fos; supplementary in vivo experiments in a mouse sepsis model; and a preliminary clinical cohort analysis were incorporated to strengthen mechanistic and translational relevance.
Results:
LPS stimulation significantly upregulated PDPN expression at both mRNA and protein levels in macrophages. SZ168 treatment reduced LPS-induced secretion of IL-6, TNF-α, and IL-1β; promoted anti-inflammatory polarization; and attenuated apoptosis. Revision-stage Western blot analyses further showed coordinated recovery of MEK, p90RSK, c-Fos, and p-ERK together with suppression of SERPINE1 after SZ168 treatment, especially in PDPN-knockdown cells. Supplementary in vivo experiments showed lower BUN, creatinine, inflammatory cytokines, and lung injury after SZ168 treatment. In a preliminary clinical cohort, serum PDPN levels were higher in patients with sepsis than in controls (23.81 ± 17.64 vs. 3.53 ± 0.58, p < 0.001).
Conclusion:
The PDPN monoclonal antibody SZ168 attenuates inflammatory responses, promotes anti-inflammatory macrophage polarization, and inhibits apoptosis through modulation of the ERK signaling pathway in LPS-induced macrophages. The supplementary in vivo and preliminary human data added during revision further support the translational relevance of PDPN as a therapeutic target in sepsis.
Insights
This study shows that Podoplanin (PDPN) is upregulated in sepsis and that the monoclonal antibody SZ168 can reduce inflammation and apoptosis in macrophages. These findings suggest PDPN is a potential therapeutic target for sepsis treatment.
Area of Science:
- Immunology
- Molecular Biology
- Pathology
Background:
- Sepsis involves excessive inflammation and immune dysregulation, with macrophages playing a central role.
- Podoplanin (PDPN), a transmembrane glycoprotein, is found on inflammatory macrophages, but its specific function in sepsis is not well understood.
Purpose of the Study:
- To investigate the role of PDPN in lipopolysaccharide (LPS)-induced macrophages.
- To evaluate the therapeutic potential of the monoclonal antibody SZ168 targeting PDPN in sepsis.
- To validate findings through in vivo and preliminary clinical studies.
Main Methods:
- RAW264.7 macrophages were stimulated with LPS and treated with SZ168.
- Assessed PDPN expression, cytokine secretion, polarization, apoptosis, and ERK signaling using proteomics, qPCR, Western blotting, ELISA, and flow cytometry.
- Utilized siRNA for PDPN knockdown and conducted in vivo mouse sepsis models and a preliminary clinical cohort analysis.
Main Results:
- LPS stimulation increased PDPN expression in macrophages.
- SZ168 treatment reduced pro-inflammatory cytokines (IL-6, TNF-α, IL-1β), promoted anti-inflammatory macrophage polarization, and decreased apoptosis.
- In vivo studies showed reduced organ injury markers and inflammation; clinical data indicated elevated serum PDPN in sepsis patients.
Conclusions:
- The PDPN monoclonal antibody SZ168 effectively reduces inflammatory responses and apoptosis in macrophages via ERK signaling modulation.
- PDPN is a promising therapeutic target for sepsis, supported by in vitro, in vivo, and preliminary clinical evidence.
