Bone marrow-derived alternatively activated macrophages reduce colitis without promoting fibrosis: participation of IL-10

Alternatively activated macrophages (AAMs) (or M2a) can inhibit colitis but may also be associated with fibrosis. Thus, by using the dinitrobenzene sulfonic (DNBS) murine model of colitis, this study aimed to determine whether 1) bone marrow (BM)-derived AAMs could reduce colitis, 2) any anticolitic effect of BM-AAMs was IL-10 dependent, and 3) repeated AAM treatments remained effective and were associated with fibrosis in the gut or other tissues. Balb/c mice received AAMs (106 intraperitoneally) from wild-type (WT) or IL-10−/− mice 48 h prior to DNBS (3 mg intrarectally) with disease assessed 72 h later, or they received three doses of DNBS at 2-wk intervals ± AAMs 6 h post-DNBS to mimic a treatment regimen. DNBS-treated mice developed colitis; this was significantly less severe in mice receiving WT AAMs and less so in animals given IL-10−/− AAMs, indicating a role for IL-10 in the inhibition of DNBS-driven colitis. Similarly, after the third AAM treatment lesser colonic histopathology was observed compared with time-matched DNBS-only-treated animals, and notably there was no evidence of increased fibroses in the colon, terminal ileum, lung, or liver of AAM-treated mice as assessed by quantitative PCR for prolyl-4-hydrolase, α-smooth muscle actin, and collagen (type IIIα) and histochemical and biochemical assessment of collagen deposition. This study provides mechanistic insight to the anticolitic capacity of AAMs and indicates that repeated adoptive transfer of ex vivo programmed BM-AAMs is safe and efficacious in the treatment of DNBS-induced murine colitis, providing additional support for their consideration as an immunotherapy.

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Mesenchymal Stem Cells Convert Human Macrophages to a Novel Type of Alternatively Activated Macrophages.

Blood ◽

10.1182/blood.v114.22.3632.3632 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3632-3632 ◽

Cited By ~ 1

Author(s):

Jaehyup Kim ◽

Peiman Hematti

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Mesenchymal Stem Cells ◽

Cell Surface ◽

Activated Macrophages ◽

Alternatively Activated Macrophages ◽

Tnf Α ◽

Low Levels ◽

Alternatively Activated

Abstract Abstract 3632 Poster Board III-568 Mesenchymal stem cells (MSCs) are capable of modulating the immune system through interaction with a wide range of immune cells. This study investigates the hypothesis that interaction of MSCs with macrophages could play a significant role in their anti-inflammatory/immune modulatory effects. All studies were approved by IRB of University of Wisconsin School of Medicine and Public Health. MSCs were culture expanded from discarded bone marrow filters after bone marrow harvest from normal healthy sibling HLA-matched donors. We used passages -35 for our experiments. Ex vivo culture expanded MSCs were characterized by their cell surface phenotype (positive for MSC markers: CD29, CD44, CD73, CD90, and CD105; and negative for hematopoietic markers: CD31, CD34, and CD45), and their differentiation potential into bone, fat and cartilage. Monocytes were isolated from peripheral blood mononuclear cell fraction of healthy donors using CD14+ Miltenyi magnetic bead cell separation method. We cultured human CD14+ monocytes for seven days without any added cytokines to generate macrophages, and then co-cultured them for three more days with culture-expanded MSCs. We used cell surface antigen expression and intracellular cytokine expression patterns to study the immunophenotype of macrophages at the end of this co-culture period, and phagocytic assays to investigate their functional activity in vitro. Macrophages co-cultured with MSCs consistently showed high level expression of CD206, a marker of alternatively activated macrophages, in addition to being positive fro CD14 marker. Using CD1a and CD209 staining we did not detect presence of any dendritic cells either at the end of seven days culture of monocyte-derived macrophages or at the end of co-culture period. Furthermore, macrophages that were co-cultured with MSCs expressed high levels of IL-10 and low levels of IL-12, as determined by intracellular staining, typical of alternatively activated macrophages. However, macrophages co-cultured with MSCs also expressed high levels of IL-6 and low levels of TNF-α, compared to controls. Functionally, macrophages co-cultured with MSCs showed a higher level of phagocytic activity using Alexa 488-conjugated E. coli phagocytic assay. In summary we describe a novel type of human macrophage generated in vitro after co-culture with MSCs that assume an immunophenotype defined as IL-10 high, IL-12 low, IL-6 high and TNF-α low secreting cells. These MSC-educated macrophages may be a unique and novel type of alternatively activated macrophages with potentially significant role in tissue repair. Disclosures: No relevant conflicts of interest to declare.

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Signal Transducer and Activator of Transcription Factor 6 Signaling Contributes to Control Host Lung Pathology but Favors Susceptibility againstToxocara canisInfection

BioMed Research International ◽

10.1155/2013/696343 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Berenice Faz-López ◽

Yadira Ledesma-Soto ◽

Yolanda Romero-Sánchez ◽

Elsa Calleja ◽

Pablo Martínez-Labat ◽

...

Keyword(s):

Toxocara Canis ◽

Lung Pathology ◽

Activated Macrophages ◽

Wild Type ◽

Gastrointestinal Helminths ◽

Th2 Response ◽

Alternatively Activated Macrophages ◽

Severe Pathology ◽

Alternatively Activated

UsingSTAT6−/−BALB/c mice, we have analyzed the role of STAT6-induced Th2 response in determining the outcome of experimental toxocariasis caused by embryonated eggs of the helminth parasiteToxocara canis. FollowingT. canisinfection wild-type BALB/c mice developed a strong Th2-like response, produced high levels of IgG1, IgE, and IL-4, recruited alternatively activated macrophages, and displayed a moderate pathology in the lungs; however, they harbored heavy parasite loads in different tissues. In contrast, similarly infectedSTAT6−/−BALB/c mice mounted a weak Th2-like response, did not recruit alternatively activated macrophages, displayed a severe pathology in the lungs, but efficiently controlledT. canisinfection. These findings demonstrate that Th2-like response induced via STAT6-mediated signaling pathway mediates susceptibility to larval stage ofT. canis. Furthermore, they also indicate that unlike most gastrointestinal helminths, immunity against larvae ofT. canisis not mediated by a Th2-dominant response.

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SIRPα sequesters SHP-2 to promote IL-4/13 signaling and alternative activation of macrophages

10.1101/2021.08.06.455421 ◽

2021 ◽

Author(s):

Lei Shi ◽

Koby Kidder ◽

Zhen Bian ◽

Samantha Kuon Ting Chiang ◽

Corbett Ouellette ◽

...

Keyword(s):

Wound Healing ◽

Ex Vivo ◽

Experimental Colitis ◽

Alternative Activation ◽

Activated Macrophages ◽

Negative Regulators ◽

Impaired Wound Healing ◽

Alternatively Activated Macrophages ◽

Arginase 1 ◽

Alternatively Activated

The Th2 cytokines IL-4 and IL-13 through activation of their shared receptor IL-4Rα direct macrophage alternative activation to promote immunosuppression and wound healing. However, the mechanisms that control macrophage responses to IL-4/13 are not fully understood. Apart from driving JAK-STAT and PI3K-Akt pathways to polarize macrophages toward the alternative phenotype, the activated IL-4/13 receptors recruit negative regulators SHP-1 and SHP-2, which dephosphorylate IL-4Rα and decrease its signaling. Here we report that SIRPα spatially restricts SHP-2 and, by such, promotes IL-4/13 signaling and macrophage alternative activation. SIRPα executes this regulation via its cytoplasmic ITIMs/ITSMs that undergo phosphorylation by IL-4/13-induced, Src kinase-activated Brutons tyrosine kinase (Btk), resulting in recruitment of SHP-2 and preclusion of SHP-2 from binding to and inhibiting IL-4/13 receptors. Despite that this regulation occurs independent of CD47, extracellular CD47 ligation of SIRPα facilitates its cytoplasmic phosphorylation and SHP-2 sequestration, leading to stronger IL-4/13 signaling and enhanced macrophage expression of IL-10, TGFβ, CD206, arginase-1, etc. Conversely, deficiency of SIRPα allows SHP-2 to freely bind to γC or IL-13Rα1 and through which dephosphorylate IL-4Rα, dampening its signaling. Consistent with these findings, impaired wound healing in Sirpα-/- mice under experimental colitis correlated with a deficit of immunosuppressive macrophages in the colon, a condition that was corrected by transfusion of ex vivo-produced SIRPαhigh alternatively activated macrophages.

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