LECT2 association with macrophage-mediated killing of Helicobacter pylori by activating NF-κB and nitric oxide production.
Helicobacter pylori employs unique methods to colonize the stomach, which induces chronic inflammation. It is also able to avoid eradication by macrophages and other immune cells. Leukocyte cell-derived chemotaxin 2 (LECT2), a multi-functional cytokine involved in many pathological conditions, has recently been shown to activate macrophages via the CD209a receptor. Therefore, we aimed to investigate the effects of LECT2 on H. pylori-infected macrophages. Macrophages were treated with recombinant LECT2, and both their ability to kill H. pylori and produce nitric oxide were analyzed. Western blot was performed to determine nuclear translocation and protein phosphorylation of p65, a subunit of nuclear factor (NF)-κB. Transfection experiments were performed to analyze the signaling pathway of LECT2 in macrophages. We found that treatment with LECT2 enhanced H. pylori killing and nitric oxide production in macrophages. In addition, DNA-binding activity and nuclear translocation of p65 were up-regulated by LECT2 treatment. Furthermore, we found that NF-κB activation by LECT2 was mediated by Raf-1 in macrophages, and Raf-1 phosphorylation was specifically altered in response to LECT2. Moreover, LECT2 induced Ser28 phosphorylation in the intracellular domain of CD209a. CD209a Ser28 phosphorylation was required for LECT2-induced Raf-1 and NF-κB activation in RAW264.7 macrophages. Our study showed that the effects of LECT2 on H. pylori killing and nitric oxide production were dependent on CD209a phosphorylation, Raf-1, and NF-κB activation. Together, these results demonstrate for the first time that exposure to LECT2 can modulate specific intracellular mechanisms downstream of CD209a to enhance H. pylori killing and nitric oxide production in macrophages.
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China.
H X
HX
Shen
Department of Gastroenterology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
L
L
Li
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China.
Q
Q
Chen
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China.
Y Q
YQ
He
Department of Gastroenterology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
C H
CH
Yu
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China.
C Q
CQ
Chu
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China lxj711043@163.com.
X J
XJ
Lu
Laboratory of Biochemistry and Molecular Biology, Ningbo University, Ningbo, China lxj711043@163.com.
J
J
Chen
D000818:Animals; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000276:immunology; D016481:Helicobacter Infections / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology / Q000472:pathogenicity; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000494:pharmacology; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis / Q000235:genetics; D010766:Phosphorylation; D000067996:RAW 264.7 Cells; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics* / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics; D013270:Stomach / Q000276:immunology / Q000382:microbiology; D051996:Transcription Factor RelA / Q000096:biosynthesis* / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D014162:Transfection; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D015815:Cell Adhesion Molecules; D036341:Intercellular Signaling Peptides and Proteins; D037181:Lectins, C-Type; D009569:Nitric Oxide; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D051996:Transcription Factor RelA; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C491213:Lect2 protein, mouse; C498144:Rela protein, mouse