Dataset Information

Lower Oligomeric Form of Surfactant Protein D in Murine Acute Lung Injury Induces M1 Subtype Macrophages Through Calreticulin/p38 MAPK Signaling Pathway.

ABSTRACT: Surfactant protein D (SP-D) plays an important role in innate and adaptive immune responses. In this study, we found that the expression of total and de-oligomerized SP-D was significantly elevated in mice with lipopolysaccharide (LPS)-induced acute lung injury (ALI). To investigate the role of the lower oligomeric form of SP-D in the pathogenesis of ALI, we treated bone marrow-derived macrophages (BMDMs) with ALI-derived bronchoalveolar lavage (BAL) and found that SP-D in ALI BAL predominantly bound to calreticulin (CALR) on macrophages, subsequently increasing the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and expression of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, IL-10, and CD80. However, anti-SP-D (aSP-D) and anti-calreticulin (aCALR) pretreatment reversed the SP-D binding and activation of macrophages induced by ALI BAL or de-oligomerized recombinant murine SP-D (rSP-D). Lack of signal transducer and activator of transcription (STAT)6 in STAT6-/- macrophages resulted in resistance to suppression by aCALR. Further studies in an ALI mouse model showed that blockade of pulmonary SP-D by intratracheal (i.t.), but not intraperitoneal (i.p.), administration of aSP-D attenuated the severity of ALI, accompanied by lower neutrophil infiltrates and expression of IL-1beta and IL-6. Furthermore, i.t. administration of de-oligomerized rSP-D exacerbated the severity of ALI in association with more pro-inflammatory CD45+Siglec-F(-) M1 subtype macrophages and production of IL-6, TNF-alpha, IL-1beta, and IL-18. The results indicated that SP-D in the lungs of murine ALI was de-oligomerized and participated in the pathogenesis of ALI by predominantly binding to CALR on macrophages and subsequently activating the pro-inflammatory downstream signaling pathway. Targeting de-oligomerized SP-D is a promising therapeutic strategy for the treatment of ALI and acute respiratory distress syndrome (ARDS).

SUBMITTER: Li D

PROVIDER: S-EPMC8415422 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Calreticulin (CALR) has anti-tumor effects by increasing dendritic cell maturation and tumor antigen presentation. However, whether CALR affects macrophages and modulates progression of acute respiratory distress syndrome/acute lung injury (ARDS/ALI) remains unknown. In this study, we discovered that CALR protein was highly expressed in the mice with LPS-induced ALI and CALR expression level was positively correlated to the severity of ALI. Commercial anti-CALR antibody (aCALR) can neutralize recombinant CALR (rCALR) and suppress the expression of TNF-alpha and IL-6 in the rCALR-treated macrophages. Blocking CALR activity by intraperitoneal (i.p.) administration of aCALR significantly suppressed ALI, accompanied with lower total cell counts, neutrophil and T cell infiltration in bronchoalveolar lavage (BAL) and lung tissues. The expression of CXCL15, IL-6, IL-1beta, TNF-alpha, and CALR were significantly reduced, in association with more polarization of Siglec F+CD206+M2 subtype macrophages in the aCALR-treated mice. Pre-depletion of circulating monocytes did not abolish the aCALR-mediated suppression of ALI. Further analysis in bone marrow-derived macrophages (BMDMs) showed that aCALR suppressed the expression of CD80, IL-6, IL-1beta, IL-18, NLRP3, and p-p38 MAPK; but enhanced the expression of CD206 and IL-10. In addition, we observed more expression and phosphorylation of STAT6 in the aCALR-treated BMDM. Lack of STAT6 resulted in comparable and slightly higher expression of CALR, TNF-alpha and IL-6 in the aCALR-treated STAT6-/- BMDMs than the untreated cells. Therefore, we conclude that CALR is a novel biomarker in the evaluation of ALI. Blocking CALR activity by aCALR effectively suppressed ALI independent of circulating monocytes. Siglec F+CD206+M2 subtype macrophages and p38 MAPK/STAT6 signaling pathway played important role in the immune regulation of aCALR. Blocking CALR activity is a promising therapeutic approach in the treatment of ARDS/ALI.

Project description:Objectives: Colistin has been identified in a Caenorhabditis elegans chemical screening as an immunostimulatory agent that activates the conserved p38/PMK-1 pathway and provides protection against pathogens. Here we aimed to extend those findings to a mammalian model and evaluate the immunomodulatory effects of colistin on rat macrophages. Methods: Macrophages were isolated from Sprague-Dawley (SD) rat. The effects of colistin on the cytokine secretion, phagocytic activity and protein expression were determined by enzyme-linked immunosorbent assay (ELISA), flow cytometry, and Western blotting analysis, respectively. The relative microRNA expression was determined by microarray, and Kyoto Encylopedia of Genes and Genomes (KEGG) was used to identify potential signaling pathways. Results: Our data showed that 5, 10, and 20 µg/ml colistin significantly increased the secretion of TNF-α, while 20 and 5 µg/ml colistin significantly increased the levels of IL-1β and IL-6, respectively. Flow cytometry results showed that the relative mean fluorescence intensity and percentage of phagocytosis in colistin treatment groups were significantly higher compared with the control group, while the increased phagocytosis phenomenon can be blocked by p38 inhibitor. The phagocytic ability of macrophages against Staphylococcus aureus was significantly increased after colistin treatment. Microarray and KEGG pathway analyses revealed that mitogen-activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), chemokine, and B cell receptor were the main pathways involved in the colistin stimulation process. Western blotting analysis demonstrated that the phosphorylated p38 protein level of colistin treatment groups was increased in a dose dependent manner. Conclusions: Present study is the first to demonstrate that colistin had immunomodulatory effects on macrophages in mammals, and the p38/MAPK pathway was involved in such colistin-induced immunomodulatory effect.

Project description:BackgroundPolyporus polysaccharide (PPS), an active ingredient of traditional Chinese medicinal Polyporus umbellatus, has multiple biological functions, such as anti-cancer, immune-regulating and hepatoprotective activities. The purpose of this study was to investigate the mechanism of homogeneous polyporus polysaccharide (HPP) activated macrophages in the treatment of bladder cancer.Methods100 ng/mL Phorbol myristate acetate (PMA) was used to induce THP-1 human leukemic cells as a macrophage model. Then macrophages derived from THP-1 were treated with different concentrations of HPP (1, 10 and 100 μg/mL). Flow cytometry and RT-PCR were used to detected the expression of CD16, CD23, CD86, CD40 and interleukin (IL)-Iβ, iNOS mRNA. ELISA was used to test the change of IL-1β and TNF-α in macrophage after the treatment with HPP. The conditioned medium from HPP-polarized macrophages was used to detect the effect of activated macrophages on bladder cancer. MTT assay, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, Transwell assay, and Western blot analysis were used to detect the effects of polarized macrophages on the viability, proliferation, apoptosis, and migration of bladder cancer cells. Western blot was also used to analysis the change of JAK2/NF-κB pathway protein.ResultsHPP promoted the expression of pro-inflammatory factors, such as IL-Iβ, TNF-α and iNOS, and surface molecules CD86, CD16, CD23, and CD40 in macrophages and then polarized macrophages to M1 type. Results demonstrated that activated macrophages inhibited the proliferation of bladder cancer cells, regulated their apoptosis, and inhibited migration and epithelial-mesenchymal transformation (EMT). JAK2/NF-κB pathways were downregulated in the anti-bladder cancer process of activated macrophages.ConclusionThe findings indicated that HPP inhibited the proliferation and progression of bladder cancer by the polarization of macrophages to M1 type, and JAK2/NF-κB pathway was downregulated in the process of anti-bladder cancer.

Dataset Information

Lower Oligomeric Form of Surfactant Protein D in Murine Acute Lung Injury Induces M1 Subtype Macrophages Through Calreticulin/p38 MAPK Signaling Pathway.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets