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Abstract Background Macrophages are key inflammatory immune cells that orchestrate the initiation and progression of autoimmune diseases. The characters of macrophage in diseases are determined by its phenotype in response to the local microenvironment. Ficolins have been confirmed as crucial contributors to autoimmune diseases, with Ficolin-2 being particularly elevated in patients with autoimmune diseases. However, whether Ficolin-A stimulates macrophage polarization is still poorly understood. Methods We investigated the transcriptomic expression profile of murine bone marrow-derived macrophages (BMDMs) stimulated with Ficolin-A using RNA-sequencing. To further confirm a distinct phenotype activated by Ficolin-A, quantitative RT-PCR and Luminex assay were performed in this study. Additionally, we assessed the activation of underlying cell signaling pathways triggered by Ficolin-A. Finally, the impact of Ficolin-A on macrophages were investigated in vivo through building Collagen-induced arthritis (CIA) and Dextran Sulfate Sodium Salt (DSS)-induced colitis mouse models with Fcna-/- mice. Results Ficolin-A activated macrophages into a pro-inflammatory phenotype distinct to LPS-, IFN-γ- and IFN-γ + LPS-induced phenotypes. The transcriptomic profile induced by Ficolin-A was primarily characterized by upregulation of interleukins, chemokines, iNOS, and Arginase 1, along with downregulation of CD86 and CD206, setting it apart from the M1 and M2 phenotypes. The activation effect of Ficolin-A on macrophages deteriorated the symptoms of CIA and DSS mouse models, and the deletion of Fcna significantly alleviated the severity of diseases in mice. Conclusion Our work used transcriptomic analysis by RNA-Seq to investigate the impact of Ficolin-A on macrophage polarization. Our findings demonstrate that Ficolin-A induces a novel pro-inflammatory phenotype distinct to the phenotypes activated by LPS, IFN-γ and IFN-γ + LPS on macrophages.

Background: Macrophages are key inflammatory immune cells that orchestrate the initiation and progression of autoimmune diseases. The characters of macrophage in diseases are determined by its phenotype in response to the local microenvironment. Ficolins have been confirmed as crucial contributors to autoimmune diseases, with Ficolin-2 being particularly elevated in patients with autoimmune diseases. However, whether Ficolin-A stimulates macrophage polarization is still poorly understood. Methods: We investigated the transcriptomic expression profile of murine bone marrow-derived macrophages (BMDMs) stimulated with Ficolin-A using RNA-sequencing. To further confirm a distinct phenotype activated by Ficolin-A, quantitative RT-PCR and Luminex assay were performed in this study. Additionally, we assessed the activation of underlying cell signaling pathways triggered by Ficolin-A. Finally, the impact of Ficolin-A on macrophages were investigated in vivo through building Collagen-induced arthritis (CIA) and Dextran Sulfate Sodium Salt (DSS)-induced colitis mouse models with Fcna-/- mice. Results: Ficolin-A activated macrophages into a pro-inflammatory phenotype distinct to LPS-, IFN-γ- and IFN-γ + LPS-induced phenotypes. The transcriptomic profile induced by Ficolin-A was primarily characterized by upregulation of interleukins, chemokines, iNOS, and Arginase 1, along with downregulation of CD86 and CD206, setting it apart from the M1 and M2 phenotypes. The activation effect of Ficolin-A on macrophages deteriorated the symptoms of CIA and DSS mouse models, and the deletion of Fcna significantly alleviated the severity of diseases in mice. Conclusion: Our work used transcriptomic analysis by RNA-Seq to investigate the impact of Ficolin-A on macrophage polarization. Our findings demonstrate that Ficolin-A induces a novel pro-inflammatory phenotype distinct to the phenotypes activated by LPS, IFN-γ and IFN-γ + LPS on macrophages. [ABSTRACT FROM AUTHOR]

Highlights • LPS-induced inflammation can induce a significant ficolin response in mice. • Murine ficolin mRNA- and protein levels is induced upon LPS challenge, exhibiting acute phase behavior. • Ficolin expression and protein secretion seem to be regulated by a negative feedback mechanism. • Two novel sandwich ELISAs was established based on rat monoclonal antibodies against murine ficolins. Abstract The ficolins belong to an important family of pattern recognition molecules, which contributes to complement activation via the lectin pathway. How the ficolins respond to inflammatory stimuli remains only partly understood. In the present study, we investigated the ficolin A and ficolin B expression and protein distribution patterns in a mouse model of LPS-induced inflammation. The time- and tissue-specific expression of ficolin A and B was determined by real time PCR. Furthermore, ficolin protein levels in serum and bone marrow extracts from LPS challenged mice were determined by novel in-house developed sandwich ELISAs. Ficolin A was mainly expressed in liver and spleen. However, our data also suggested that ficolin A is expressed in bone marrow, which is the main site of ficolin B expression. The level of ficolin A and B expression was increased after stimulation with LPS in the investigated tissues. This was followed by a downregulation of expression, causing mRNA levels to return to baseline 24 h post LPS challenge. Protein levels appeared to follow the same pattern as the expression profiles, with an exception of ficolin B levels in serum, which kept increasing for 24 h. Ficolin A was likewise significantly increased in bronchoalveolar lavage fluid from mice infected with the fungi A. fumigatus , pointing towards a similar effect of the ficolins in non-sterile mouse models of inflammation. The results demonstrate that LPS-induced inflammation can induce a significant ficolin response, suggesting that the murine ficolins are acute phase reactants with increase in both mRNA expression and protein levels during systemic inflammation. [ABSTRACT FROM AUTHOR]

Human ficolin-2 ( FCN-2) and mouse ficolin-A ( FCN-A, a ficolin-2-like molecule in mouse) are activators of the lectin complement pathway, present in normal plasma and usually associated with infectious diseases, but little is known about the role of FCN-A/2 in inflammatory bowel disease ( IBD). In our present study, we found that patients with IBD exhibited much higher serum FCN-2 levels than healthy controls. In the dextran sulphate sodium-induced acute colitis mouse model, FCN-A knockout mice showed much milder disease symptoms with less histological damage, lower expression levels of pro-inflammatory cytokines [interleukin-6 ( IL-6), IL-1 β and tumour necrosis factor- α (TNF- α)], chemokines ( CXCL1/2/10 and CCL4) and higher levels of the anti-inflammatory cytokine IL-10 compared with wild-type mice. We demonstrated that FCN-A/2 exacerbated the inflammatory pathogenesis of IBD by stimulating M1 polarization through the TLR4/MyD88/ MAPK/ NF- κB signalling pathway in macrophages. Hence, our data suggest that FCN-A/2 may be used as a novel therapeutic target for IBD. [ABSTRACT FROM AUTHOR]

Background: Malaria remains a serious public health problem with significant morbidity and mortal­ity. This study was conducted to identify whether ficolin-A could play an active role of against mala­ria infection.Methods: The function of ficolin-A was analyzed in mouse model. The open reading frame of fico­lin-A was cloned from the liver of new born C57BL/6 mice by RT-PCR and then inserted into the expression vector of eukaryon to construct pVAX1-ficolin-A plasmid. Meanwhile, the open reading frame of the 19-kDa fragment of merozoite surface protein-1 of Plasmodium berghei (MSP119) was cloned and then the expression vector of eukaryon, pVAX1- MSP119 was constructed. Both recombi­nant vectors were used in the mouse model of infection by Plasmodium berghei.Results: pVAX1-ficolin-A alone could not significantly suppress parasite density and prolong sur­vival time of infection mice; however, when injected pVAX1-ficolin-A and pVAX1- MSP119 together, the percent of invasion by Plasmodium was decreased (from 43.78% to 22.23% at 10 day after infec­tion, compared to vector ) and the survival time was prolonged significantly in the infection mouse model (P=0.01).Conclusion: Ficolin-A can enhance the immunoprotection of MSP119, it implies ficolin-A may be used as immunoenhancer in the study of vaccine defending malaria

Background: Malaria remains a serious public health problem with significant morbidity and mortal-ity. This study was conducted to identify whether ficolin-A could play an active role of against mala-ria infection. Methods: The function of ficolin-A was analyzed in mouse model. The open reading frame of fico-lin-A was cloned from the liver of new born C57BL/6 mice by RT-PCR and then inserted into the expression vector of eukaryon to construct pVAX1-ficolin-A plasmid. Meanwhile, the open reading frame of the 19-kDa fragment of merozoite surface protein-1 of Plasmodium berghei (MSP119) was cloned and then the expression vector of eukaryon, pVAX1- MSP119 was constructed. Both recom-binant vectors were used in the mouse model of infection by Plasmodium berghei. Results: pVAX1-ficolin-A alone could not significantly suppress parasite density and prolong sur-vival time of infection mice; however, when injected pVAX1-ficolin-A and pVAX1- MSP119 together, the percent of invasion by Plasmodium was decreased (from 43.78% to 22.23% at 10 day after infec-tion, compared to vector ) and the survival time was prolonged significantly in the infection mouse model (P=0.01). Conclusion: Ficolin-A can enhance the immunoprotection of MSP119, it implies ficolin-A may be used as immunoenhancer in the study of vaccine defending malaria.

Abstract: Cryptococcus neoformans is a pathogenic fungus causing life threatening infections in humans. The present in vitro study aimed to investigate the opsonizing properties of a well characterized serum ficolin (rat ficolin-A), a member of carbohydrate-recognition molecules of the innate immune system, in the defence against this fungal pathogen. Using flow cytometric analysis we have been able to demonstrate that ficolin-A readily binds to two different acapsular C. neoformans serotypes (representative of the primary infectious form of this fungus) whereas the encapsulated forms are not being recognized. The ficolin-A binding was concentration dependant and inhibited by the acetylated sugars N-acetyleglucosamine and N-acetylegalactosamine but less so by galactose, glucose and mannan. The binding was enhanced at acidic pHs (5.7 and 4.7) compared to physiological pH (7.4) which may indicate that the carbohydrate recognizing fibrinogen-like domains of ficolins undergo conformational changes providing more efficient binding at sites of inflammation where the pH is much lower than normal. We further assessed the biological consequence of the ficolin-A recognition of acapsular C. neoformans by investigating their interaction with lung epithelial cells (type II pneumocytes cell line A549). Flow cytometric analysis demonstrated that ficolin-A opsonized acapsular C. neoformans showed significantly increased adherence to A549 cells when exposed to acidic conditions compared to the unopsonized controls (p =0.04). We conclude that ficolin-A binds acapsular C. neoformans via their carbohydrate recognizing fibrinogen-like domains leading to enhanced uptake by lung epithelial cells in vitro. [Copyright &y& Elsevier]

Background: Malaria remains a serious public health problem with significant morbidity and mortality. This study was conducted to identify whether ficolin-A could play an active role of against malaria infection. Methods: The function of ficolin-A was analyzed in mouse model. The open reading frame of ficolin- A was cloned from the liver of new born C57BL/6 mice by RT-PCR and then inserted into the expression vector of eukaryon to construct pVAX1-ficolin-A plasmid. Meanwhile, the open reading frame of the 19-kDa fragment of merozoite surface protein-1 of Plasmodium berghei (MSP119) was cloned and then the expression vector of eukaryon, pVAX1- MSP119 was constructed. Both recombinant vectors were used in the mouse model of infection by Plasmodium berghei. Results: pVAX1-ficolin-A alone could not significantly suppress parasite density and prolong survival time of infection mice; however, when injected pVAX1-ficolin-A and pVAX1- MSP119 together, the percent of invasion by Plasmodium was decreased (from 43.78% to 22.23% at 10 day after infection, compared to vector ) and the survival time was prolonged significantly in the infection mouse model (P=0.01). Conclusion: Ficolin-A can enhance the immunoprotection of MSP119, it implies ficolin-A may be used as immunoenhancer in the study of vaccine defending malaria. [ABSTRACT FROM AUTHOR]