RNA editing enzyme APOBEC3A promotes pro-inflammatory (M1) macrophage polarization

AbstractPro-inflammatory (M1) macrophage polarization is associated with microbicidal and antitumor responses. We recently described APOBEC3A-mediated cytosine-to-uracil (C>U) RNA editing during M1 polarization. However, the functional significance of this editing is unknown. Here, we find that APOBEC3A-mediated cellular RNA editing can also be induced by influenza or Maraba virus infections of normal human macrophages, and by interferons in tumor-associated macrophages. Gene knockdown and RNA_Seq analyses show that APOBEC3A mediates C>U RNA editing of 209 exonic/UTR sites in 203 genes during M1 polarization. The highest level of deleterious C>U RNA editing occurred in THOC5, encoding a nuclear mRNA export protein implicated in M-CSF-driven macrophage differentiation. Knockdown of APOBEC3A reduces pro-inflammatory M1 markers including IL6, IL23A and IL12B gene expression, CD86 surface protein expression, and TNF-α, IL-1β and IL-6 cytokine secretion, and increases glycolysis and glycolytic capacity. Thus, APOBEC3A cytidine deaminase plays an important role in transcriptomic and functional polarization of M1 macrophages.

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RNA editing enzyme APOBEC3A promotes pro-inflammatory M1 macrophage polarization

Communications Biology ◽

10.1038/s42003-020-01620-x ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Emad Y. Alqassim ◽

Shraddha Sharma ◽

A. N. M. Nazmul H. Khan ◽

Tiffany R. Emmons ◽

Eduardo Cortes Gomez ◽

...

Keyword(s):

Rna Editing ◽

Cytidine Deaminase ◽

Macrophage Polarization ◽

Surface Protein ◽

Virus Infections ◽

M1 Polarization ◽

M1 Macrophage ◽

Surface Protein Expression ◽

Functional Polarization ◽

Editing Enzyme

AbstractPro-inflammatory M1 macrophage polarization is associated with microbicidal and antitumor responses. We recently described APOBEC3A-mediated cytosine-to-uracil (C > U) RNA editing during M1 polarization. However, the functional significance of this editing is unknown. Here we find that APOBEC3A-mediated cellular RNA editing can also be induced by influenza or Maraba virus infections in normal human macrophages, and by interferons in tumor-associated macrophages. Gene knockdown and RNA_Seq analyses show that APOBEC3A mediates C>U RNA editing of 209 exonic/UTR sites in 203 genes during M1 polarization. The highest level of nonsynonymous RNA editing alters a highly-conserved amino acid in THOC5, which encodes a nuclear mRNA export protein implicated in M-CSF-driven macrophage differentiation. Knockdown of APOBEC3A reduces IL6, IL23A and IL12B gene expression, CD86 surface protein expression, and TNF-α, IL-1β and IL-6 cytokine secretion, and increases glycolysis. These results show a key role of APOBEC3A cytidine deaminase in transcriptomic and functional polarization of M1 macrophages.

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Kaempferol Alleviates Corneal Transplantation Rejection by Inhibiting NLRP3 Inflammasome Activation and Macrophage M1 Polarization via Promoting Autophagy

10.21203/rs.3.rs-368448/v1 ◽

2021 ◽

Author(s):

Huiwen Tian ◽

Shumei Lin ◽

Jing Wu ◽

Ming Ma ◽

Jian Yu ◽

...

Keyword(s):

Nlrp3 Inflammasome ◽

Macrophage Polarization ◽

Corneal Transplantation ◽

Inflammasome Activation ◽

M1 Polarization ◽

Nlrp3 Inflammasome Activation ◽

M1 Macrophage ◽

Transplantation Rejection

Abstract Corneal transplantation rejection remains a major threat to the success rate in high-risk patients. Given the many side effects presented by traditional immunosuppressants, there is an urgency to clarify the mechanism of corneal transplantation rejection and to identify new therapeutic targets. Kaempferol is a natural flavonoid that has been proven in various studies to possess anti-inflammatory, antioxidant, anticancer, and neuroprotective properties. However, the relationship between kaempferol and corneal transplantation remains largely unexplored. To address this, both in vivo and in vitro, we established a model of corneal allograft transplantation in Wistar rats and an LPS-induced inflammatory model in THP-1 derived human macrophages. In the transplantation experiments, we observed an enhancement in the NLRP3 / IL-1 β axis and in M1 macrophage polarization post-operation. In groups to which kaempferol intraperitoneal injections were administered, this response was effectively reduced. However, the effect of kaempferol was reversed after the application of autophagy inhibitors. Similarly, in the inflammatory model, we found that different concentrations of kaempferol can reduce the LPS-induced M1 polarization and NLRP3 inflammasome activation. Moreover, we confirmed that kaempferol induced autophagy and that autophagy inhibitors reversed the effect in macrophages. In conclusion, we found that kaempferol can inhibit the activation of the NLRP3 inflammasomes by inducing autophagy, thus inhibiting macrophage polarization, and ultimately alleviating corneal transplantation rejection. Thus, our study suggests that kaempferol could be used as a potential therapeutic agent in the treatment of allograft rejection.

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Taurine Antagonizes Macrophages M1 Polarization by Mitophagy-Glycolysis Switch Blockage via Dragging SAM-PP2Ac Transmethylation

Frontiers in Immunology ◽

10.3389/fimmu.2021.648913 ◽

2021 ◽

Vol 12 ◽

Author(s):

Ling Meng ◽

Cailing Lu ◽

Bin Wu ◽

Chunhua Lan ◽

Laiming Mo ◽

...

Keyword(s):

Energy Metabolism ◽

Inflammatory Diseases ◽

Macrophage Polarization ◽

Metabolic Adaptation ◽

Transcriptional Level ◽

Low Grade ◽

Taurine Supplementation ◽

Polarization Model ◽

M1 Polarization ◽

M1 Macrophage

The excessive M1 polarization of macrophages drives the occurrence and development of inflammatory diseases. The reprogramming of macrophages from M1 to M2 can be achieved by targeting metabolic events. Taurine promotes for the balance of energy metabolism and the repair of inflammatory injury, preventing chronic diseases and complications. However, little is known about the mechanisms underlying the action of taurine modulating the macrophage polarization phenotype. In this study, we constructed a low-dose LPS/IFN-γ-induced M1 polarization model to simulate a low-grade pro-inflammatory process. Our results indicate that the taurine transporter TauT/SlC6A6 is upregulated at the transcriptional level during M1 macrophage polarization. The nutrient uptake signal on the membrane supports the high abundance of taurine in macrophages after taurine supplementation, which weakens the status of methionine metabolism, resulting in insufficient S-adenosylmethionine (SAM). The low availability of SAM is directly sensed by LCMT-1 and PME-1, hindering PP2Ac methylation. PP2Ac methylation was found to be necessary for M1 polarization, including the positive regulation of VDAC1 and PINK1. Furthermore, its activation was found to promote the elimination of mitochondria by macrophages via the mitophagy pathway for metabolic adaptation. Mechanistically, taurine inhibits SAM-dependent PP2Ac methylation to block PINK1-mediated mitophagy flux, thereby maintaining a high mitochondrial density, which ultimately hinders the conversion of energy metabolism to glycolysis required for M1. Our findings reveal a novel mechanism of taurine-coupled M1 macrophage energy metabolism, providing novel insights into the occurrence and prevention of low-grade inflammation, and propose that the sensing of taurine and SAM availability may allow communication to inflammatory response in macrophages.

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AR Deficiency Inhibits LPS-induced M1 Response in Macrophages by Activating Autophagy

10.21203/rs.3.rs-127244/v1 ◽

2020 ◽

Author(s):

Peng Cheng ◽

Jianwei Xie ◽

Zhiyong Liu ◽

Jian Wang

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Inflammatory Responses ◽

Macrophage Polarization ◽

Critical Role ◽

Transcriptional Level ◽

Mrna Levels ◽

M1 Polarization ◽

M1 Macrophage ◽

Oxide Synthase

Abstract Macrophage M1 polarization mediates inflammatory responses and tissue damage. Recently, aldose reductase (AR) has been shown to play a critical role in of M1 polarization in macrophages. However, the underlying mechanisms are unknown. Here, we demonstrated, for the first time, that AR deficiency repressed the induction of inducible nitric oxide synthase in lipopolysaccharide (LPS)-stimulated macrophages via activation of autophagy. This suppression was related to a defect in the inhibitor of nuclear factor κB (NF-κB) kinase (IKK) complex in the classical NF-κB pathway. However, the mRNA levels of the IKKβ and IKKγ were not reduced in LPS-treated AR knockout (KO) macrophages, indicating that their proteins were downregulated at the post-transcriptional level. We discovered that LPS stimuli induced the recruitment of more beclin1 and increased autophagosome formation in AR-deficient macrophages. Blocking autophagy by 3-methyladenine and ammonium chloride treatment restored IKKβ and IKKγ protein levels and increased nitric oxide synthase production in LPS-stimulated AR-deficient macrophages. More assembled IKKβ and IKKγ undergo ubiquitination and recruit the autophagic adaptor p62 in LPS-induced AR KO macrophages, promoting their delivery to autophagosomes and lysosomes. Collectively, these findings suggest that AR deficiency involves in the regulation of NF-κB signaling, and extends the role of selective autophagy in ﬁne-tuned M1 macrophage polarization.

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MiR-19a-3p Suppresses M1 Macrophage Polarization by Inhibiting STAT1/IRF1 Pathway

Frontiers in Pharmacology ◽

10.3389/fphar.2021.614044 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiaoxiao Zhu ◽

Qiang Guo ◽

Jing Zou ◽

Bin Wang ◽

Zhen Zhang ◽

...

Keyword(s):

Macrophage Polarization ◽

Luciferase Reporter ◽

Mouse Lung ◽

Interferon Regulatory Factor 1 ◽

Macrophages Polarization ◽

M1 Polarization ◽

M1 Macrophage ◽

Activated Macrophage ◽

Alternatively Activated

Macrophages, an important type of immune cells, are generally polarized to classically activated macrophage (M1) or alternatively activated macrophage (M2) to respond to environmental stimuli. Signal transducer and activator of transcription 1 (STAT1), a very important transcription factor, can promote M1 macrophage polarization. However, the mechanisms of regulating STAT1 in macrophage polarization remain unclear. In the present study, STAT1 was markedly elevated, however, miR-19a-3p was down-regulated in interferon (IFN)-γ and lipopolysaccharide (LPS) treated RAW264.7 cells, and dual-luciferase reporter assay identified that miR-19a-3p directly targeted STAT1 by binding to its 3′UTR. Up-regulated miR-19a-3p inhibited M1 polarization by targeting STAT1/interferon regulatory factor 1 (IRF1) and vice versa in vitro. Consistently, overexpression of miR-19a-3p in LPS treated mice by systemically administering agomiR-19a-3p effectively reduced the inflammation in mouse lung tissues, and inhibited M1 macrophage polarization via suppressing STAT1/IRF1 pathway. In summary, our study confirmed that miR-19a-3p, as a direct regulator of STAT1, inhibited M1 macrophages polarization. The miR-19a-3p/STAT1/IRF1 pathway can potentially be used to design novel immunotherapy for modulating macrophage polarization.

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Adipocyte-Derived Exosomes Carrying Sonic Hedgehog Mediate M1 Macrophage Polarization-Induced Insulin Resistance via Ptch and PI3K Pathways

Cellular Physiology and Biochemistry ◽

10.1159/000492252 ◽

2018 ◽

Vol 48 (4) ◽

pp. 1416-1432 ◽

Cited By ~ 17

Author(s):

Ming Song ◽

Lu Han ◽

Fang-fang Chen ◽

Di Wang ◽

Feng Wang ◽

...

Keyword(s):

Insulin Resistance ◽

Western Blot ◽

Sonic Hedgehog ◽

High Glucose ◽

Insulin Signalling ◽

Macrophage Polarization ◽

Raw 264.7 ◽

Raw 264.7 Macrophages ◽

M1 Polarization ◽

M1 Macrophage

Background/Aims: Adipocyte-derived exosomes (ADEs) stimulate the activation of macrophages and contribute to the development of insulin resistance. Sonic Hedgehog (Shh) is an exosome-carrying protein and stimulates macrophages to secrete inflammatory cytokines. However, the impact of ADEs carrying Shh on the pro-inflammatory activation of macrophages and consequently, adipocyte insulin resistance is unclear. Methods: 3T3-L1 adipocytes were cultured with high glucose and insulin to imitate the pathogeny of insulin resistance. ADEs were isolated from conditioned media of 3T3-L1 adipocytes via differential ultracentrifugation. We explored the role of ADEs carrying Shh in the polarization of macrophages by flow cytometry. Western blot and electrophoretic mobility shift assay (EMSA) were performed to determine the activation of Shh-mediated signalling pathways. The effects of ADE-treated macrophages on adipocyte insulin signalling were studied by Western blot. Results: We found that circulating Shh-positive exosomes were increased in type 2 diabetes patients. High glucose and insulin increased the secretion of Shh-positive ADEs. The ADEs carrying Shh induced pro-inflammatory or M1 polarization of bone marrow-derived macrophages (BMDM) and RAW 264.7 macrophages. Inhibitors of Ptch and PI3K blocked the M1 polarization induced by ADEs, which suggests that ADEs carrying Shh mediated M1 macrophage polarization through the Ptch/PI3K signalling pathway. ADE-treated RAW 264.7 macrophages were subsequently used to assess the effect on insulin signalling in adipocytes. Using a co-culture assay, we showed that both ADE-treated macrophages and exosomes from these macrophages could decrease the expression of insulin-resistant substrate-1 (IRS-1) and hormone-sensitive lipase (HSL) in adipocytes. Inhibitors of Ptch and PI3K blocked the down-regulation of IRS-1 and HSL induced by ADE-treated macrophages. Conclusion: Together, these data indicate that ADEs carrying Shh induce the M1 polarization of macrophages, which contributes to insulin resistance in adipocytes through the Ptch/PI3K pathway.

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Aldose reductase deficiency inhibits LPS-induced M1 response in macrophages by activating autophagy

Cell & Bioscience ◽

10.1186/s13578-021-00576-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Peng Cheng ◽

Jianwei Xie ◽

Zhiyong Liu ◽

Jian Wang

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Aldose Reductase ◽

Macrophage Polarization ◽

Critical Role ◽

Transcriptional Level ◽

Mrna Levels ◽

M1 Polarization ◽

M1 Macrophage ◽

Oxide Synthase

AbstractMacrophage M1 polarization mediates inflammatory responses and tissue damage. Recently, aldose reductase (AR) has been shown to play a critical role in M1 polarization in macrophages. However, the underlying mechanisms are unknown. Here, we demonstrated, for the first time, that AR deficiency repressed the induction of inducible nitric oxide synthase in lipopolysaccharide (LPS)-stimulated macrophages via activation of autophagy. This suppression was related to a defect in the inhibitor of nuclear factor κB (NF-κB) kinase (IKK) complex in the classical NF-κB pathway. However, the mRNA levels of IKKβ and IKKγ were not reduced in LPS-treated AR knockout (KO) macrophages, indicating that their proteins were downregulated at the post-transcriptional level. We discovered that LPS stimuli induced the recruitment of more beclin1 and increased autophagosome formation in AR-deficient macrophages. Blocking autophagy through 3-methyladenine and ammonium chloride treatment restored IKKβ and IKKγ protein levels and increased nitric oxide synthase production in LPS-stimulated AR-deficient macrophages. More assembled IKKβ and IKKγ underwent ubiquitination and recruited the autophagic adaptor p62 in LPS-induced AR KO macrophages, promoting their delivery to autophagosomes and lysosomes. Collectively, these findings suggest that AR deficiency is involved in the regulation of NF-κB signaling, and extends the role of selective autophagy in fine-tuned M1 macrophage polarization.

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Boosting innate immunity: Asaia bacteria expressing a protein from Wolbachia determine macrophage activation and killing of Leishmania

10.1101/2020.06.22.164145 ◽

2020 ◽

Author(s):

Ilaria Varotto-Boccazzi ◽

Sara Epis ◽

Irene Arnoldi ◽

Yolanda Corbett ◽

Paolo Gabrieli ◽

...

Keyword(s):

Macrophage Activation ◽

Surface Protein ◽

Vector Borne Diseases ◽

M1 Polarization ◽

M1 Macrophage ◽

Filarial Nematodes ◽

Lower Extent ◽

Bacterial Endosymbionts ◽

Vector Borne ◽

Phagocytosis Activity

AbstractLeishmaniases are severe vector-borne diseases affecting humans and animals, caused by Leishmania protozoans. Immune polarization plays a major role in determining the outcome of Leishmania infections: hosts displaying M1-polarized macrophages are protected, while those biased on the M2 side acquire a chronic infection, that could develop into an overt and potentially deadly disease. The identification of the factors involved in M1 polarization is essential for the design of therapeutic and prophylactic interventions, including vaccines. Infection by the filarial nematode Dirofilaria immitis could be one of the factors that interfere with leishmaniasis in dogs. Indeed, filarial nematodes induce a partial skew of the immune response towards M1, likely caused by their bacterial endosymbionts, Wolbachia. Here we have examined the potential of AsaiaWSP, a bacterium engineered for the expression of the Wolbachia surface protein (WSP), as an inductor of M1 macrophage activation and Leishmania killing. Macrophages stimulated with AsaiaWSP displayed a strong leishmanicidal activity, comparable to that determined by the choice-drug amphotericin B. Additionally, AsaiaWSP determined the expression of markers of classical macrophage activation, including M1 cytokines, ROS and NO, and an increase in phagocytosis activity. Asaia not expressing WSP also induced macrophage activation, although at a lower extent compared to AsaiaWSP. In summary, our study, while providing a strong evidence for the immune-stimulating properties of Wolbachia, highlights the translational potential of AsaiaWSP in the areas of the immune-prophylaxis and therapy of leishmaniases, as well as of other diseases that could be subverted by M1 macrophage activation.

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Mitochondrial hypoxic stress induces widespread RNA editing by APOBEC3G in lymphocyte

10.1101/389791 ◽

2018 ◽

Cited By ~ 3

Author(s):

Shraddha Sharma ◽

Jianmin Wang ◽

Scott Portwood ◽

Eduardo Cortes-Gomez ◽

Orla Maguire ◽

...

Keyword(s):

T Cells ◽

Rna Editing ◽

De Novo ◽

Cytidine Deaminase ◽

Mrna Translation ◽

Hypoxic Stress ◽

Mrna Editing ◽

Metabolic Remodeling ◽

Editing Enzyme ◽

Normal Health

AbstractProtein recoding by RNA editing is required for normal health and evolutionary adaptation. However, de novo induction of RNA editing in response to environmental factors is an uncommon phenomenon. While APOBEC3A edits many mRNAs in monocytes/macrophages in response to hypoxia and interferons, the physiological significance of such editing is unclear. Here we show that the related APOBEC3G cytidine deaminase induces site-specific C-to-U RNA editing in natural killer (NK), CD8+ T cells and lymphoma cell lines upon cellular crowding and hypoxia. RNASeq analysis of hypoxic NK cells reveals widespread C-to-U recoding mRNA editing that is enriched for genes involved in mRNA translation. APOBEC3G promotes Warburg-like metabolic remodeling and reduces proliferation of HuT78 T cells under similar conditions. Hypoxia-induced RNA editing by APOBEC3G can be mimicked by the inhibition of mitochondrial respiration, and occurs independently of HIF-1α. Thus, APOBEC3G is an endogenous RNA editing enzyme, which is induced by mitochondrial hypoxic stress to promote adaptation in lymphocytes.

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Light-independent M1 macrophage polarization by photosensitizer-loaded protein corona on gold nanorods

Nanomedicine ◽

10.2217/nnm-2020-0249 ◽

2020 ◽

Vol 15 (24) ◽

pp. 2329-2344

Author(s):

Joshua U-Jin Cheah ◽

Heng Boon Low ◽

Yongliang Zhang ◽

James Chen Yong Kah

Keyword(s):

Protein Expression ◽

Cell Viability ◽

Gold Nanorods ◽

Inductively Coupled Plasma ◽

Macrophage Polarization ◽

Protein Corona ◽

Cell Viability Assay ◽

M1 Polarization ◽

M1 Macrophage ◽

Gene And Protein Expression

Aim: To establish a light-independent functionality of gold nanorods (AuNRs) with a human serum (HS) protein corona loaded with photosensitizer Chlorin e6 (AuNR-HS-Ce6) in M1 polarization of macrophages. Methods: RT-qPCR and ELISA were used to determine gene and protein expression, respectively. Uptake of AuNR-HS-Ce6 was determined via flow cytometry, inductively coupled plasma mass spectrometry and fluorescence microscopy. Cell viability was determined using PrestoBlue® cell viability assay. Results: An increase in M1 gene and protein expression was observed in AuNR-HS-Ce6-treated macrophages. Delivery of high Ce6 payload via AuNR-HS-Ce6 was the primary contributor toward M1 polarization. Finally, DLD-1 cells treated with conditioned media from AuNR-HS-Ce6-treated macrophages showed significantly reduced proliferation. Conclusion: Our study suggests an immunomodulatory potential of Ce6 in inducing light-independent M1 polarization outside of its role as a photosensitizer.

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