scholarly journals The Role of TGFβ1 and Macrophage Differentiation in MSU Crystal-Induced Inflammation

2021 ◽  
Author(s):  
◽  
Stefanie Steiger

<p>Gout is a painful form of inflammatory arthritis that is caused by the deposition of monosodium urate (MSU) crystals in the joints. MSU crystals trigger a local inflammatory response initiated by resident macrophages followed by a large infiltration of leukocytes. The spontaneous resolution of acute gout is associated with the production of transforming growth factor β1 (TGFβ1). The overall objectives of this thesis were to investigate mechanisms that lead to TGFβ1 production and contribute to the resolution of acute gout, the effect of TGFβ1 on the functional phenotype of differentiated macrophages, and possible changes in surface marker expression by macrophages in response to MSU crystals.  To determine macrophage-independent sources of TGFβ1 during the resolution of acute gout and how TGFβ1 production altered MSU crystal-recruited neutrophil functions, neutrophils were purified from MSU crystal-treated mice when levels of TGFβ1 were high. MSU crystal-recruited neutrophils and circulating blood neutrophils were identified as TGFβ1⁺ cells. The mechanism for TGFβ1 production by neutrophils was associated with their ability to phagocytose apoptotic neutrophils. TGFβ1 produced by canibalising neutrophils inhibited both respiratory burst and interleukin-1β (IL-1β) production by MSU crystal-activated neutrophils ex vivo. Importantly, neutrophils from MSU crystal-challenged mice treated with TGFβ1 neutralising antibody in vivo produced elevated levels of superoxide but neutrophil IL-1β production was unaffected. These results show that TGFβ1 produced by canibalising neutrophils can actively suppress neutrophil inflammatory functions and therefore make a significant contribution towards the resolution of gouty inflammation.  To investigate the effect of TGFβ1 on macrophage differentiation in vitro, granulocyte macrophage colony-stimulating factor (GM-CSF) bone marrow macrophages (GM-BMMs) and macrophage colony-stimulating factor (M-CSF) bone marrow macrophages (M-BMMs) were generated in the presence of TGFβ1. TGFβ1 was found to drive a hyper-inflammatory GM-BMM phenotype, while contributing to the differentiation of a hypo-inflammatory M-BMM phenotype specifically in response to MSU crystals. Increased IL-1β production by TGFβ1-differentiated GM-BMMs was associated with enhanced NOD like receptor family, pyrin domain-containing 3 (NLRP3) in ammasome activation and caspase 1/caspase 8 interaction, and a down-regulation of receptor-interacting serine/threonine-protein kinase 3 (RIP3) triggered by MSU crystals. At the same, TGFβ1 inhibited antigen-specific T cell proliferation by GM-BMMs. In contrast, TGFβ1-treated M-BMMs down-regulated the expression of active IL-1β that correlated with decreased IL-1β production, and upregulated RIP3 expression in response to MSU crystals. These data indicate that TGFβ1-treated GM-BMMs exhibited a hyper-inflammatory response to MSU crystal stimulation, whereas M-BMMs were found to be hypo-responsive.  Macrophages were found to upregulate the surface marker NK1.1, which is primarily expressed on natural killer (NK) cells, and occured as a consequence of phagocytosis. Following phagocytosis of MSU crystals, activated macrophages produced IL-1β and tumour necrosis factor ⍺ (TNF⍺), which triggered the upregulation of NK1.1 expression. Macrophage NK1.1 expression is an activation-driven event specifc to MSU crystals. However, phagocytosis of apoptotic neutrophils also triggered the upregulation of NK1.1 by macrophages, a non-inflammatory event that is characteristic for the resolution of acute inflammation. These findings suggest that macrophages may develop NK cell-like properties initiated by an activation-driven or apoptotic cell clearance mechanism.  Taken together, the results of this thesis indicate that canibalising neutrophils self-regulate their inflammatory functions via TGFβ1 and that TGFβ1 drives a hyper-inflammatory GM-BMM phenotype, while shutting down inflammatory functions of M-BMMs. These data highlight a regulatory role for TGFβ1 during acute gouty inflammation.</p>

2021 ◽  
Author(s):  
◽  
Stefanie Steiger

<p>Gout is a painful form of inflammatory arthritis that is caused by the deposition of monosodium urate (MSU) crystals in the joints. MSU crystals trigger a local inflammatory response initiated by resident macrophages followed by a large infiltration of leukocytes. The spontaneous resolution of acute gout is associated with the production of transforming growth factor β1 (TGFβ1). The overall objectives of this thesis were to investigate mechanisms that lead to TGFβ1 production and contribute to the resolution of acute gout, the effect of TGFβ1 on the functional phenotype of differentiated macrophages, and possible changes in surface marker expression by macrophages in response to MSU crystals.  To determine macrophage-independent sources of TGFβ1 during the resolution of acute gout and how TGFβ1 production altered MSU crystal-recruited neutrophil functions, neutrophils were purified from MSU crystal-treated mice when levels of TGFβ1 were high. MSU crystal-recruited neutrophils and circulating blood neutrophils were identified as TGFβ1⁺ cells. The mechanism for TGFβ1 production by neutrophils was associated with their ability to phagocytose apoptotic neutrophils. TGFβ1 produced by canibalising neutrophils inhibited both respiratory burst and interleukin-1β (IL-1β) production by MSU crystal-activated neutrophils ex vivo. Importantly, neutrophils from MSU crystal-challenged mice treated with TGFβ1 neutralising antibody in vivo produced elevated levels of superoxide but neutrophil IL-1β production was unaffected. These results show that TGFβ1 produced by canibalising neutrophils can actively suppress neutrophil inflammatory functions and therefore make a significant contribution towards the resolution of gouty inflammation.  To investigate the effect of TGFβ1 on macrophage differentiation in vitro, granulocyte macrophage colony-stimulating factor (GM-CSF) bone marrow macrophages (GM-BMMs) and macrophage colony-stimulating factor (M-CSF) bone marrow macrophages (M-BMMs) were generated in the presence of TGFβ1. TGFβ1 was found to drive a hyper-inflammatory GM-BMM phenotype, while contributing to the differentiation of a hypo-inflammatory M-BMM phenotype specifically in response to MSU crystals. Increased IL-1β production by TGFβ1-differentiated GM-BMMs was associated with enhanced NOD like receptor family, pyrin domain-containing 3 (NLRP3) in ammasome activation and caspase 1/caspase 8 interaction, and a down-regulation of receptor-interacting serine/threonine-protein kinase 3 (RIP3) triggered by MSU crystals. At the same, TGFβ1 inhibited antigen-specific T cell proliferation by GM-BMMs. In contrast, TGFβ1-treated M-BMMs down-regulated the expression of active IL-1β that correlated with decreased IL-1β production, and upregulated RIP3 expression in response to MSU crystals. These data indicate that TGFβ1-treated GM-BMMs exhibited a hyper-inflammatory response to MSU crystal stimulation, whereas M-BMMs were found to be hypo-responsive.  Macrophages were found to upregulate the surface marker NK1.1, which is primarily expressed on natural killer (NK) cells, and occured as a consequence of phagocytosis. Following phagocytosis of MSU crystals, activated macrophages produced IL-1β and tumour necrosis factor ⍺ (TNF⍺), which triggered the upregulation of NK1.1 expression. Macrophage NK1.1 expression is an activation-driven event specifc to MSU crystals. However, phagocytosis of apoptotic neutrophils also triggered the upregulation of NK1.1 by macrophages, a non-inflammatory event that is characteristic for the resolution of acute inflammation. These findings suggest that macrophages may develop NK cell-like properties initiated by an activation-driven or apoptotic cell clearance mechanism.  Taken together, the results of this thesis indicate that canibalising neutrophils self-regulate their inflammatory functions via TGFβ1 and that TGFβ1 drives a hyper-inflammatory GM-BMM phenotype, while shutting down inflammatory functions of M-BMMs. These data highlight a regulatory role for TGFβ1 during acute gouty inflammation.</p>


Cytokine ◽  
2005 ◽  
Vol 31 (4) ◽  
pp. 288-297 ◽  
Author(s):  
Naoko Yamada ◽  
Tohru Tsujimura ◽  
Haruyasu Ueda ◽  
Shin-Ichi Hayashi ◽  
Hideki Ohyama ◽  
...  

2008 ◽  
Vol 295 (1) ◽  
pp. L114-L122 ◽  
Author(s):  
Megan N. Ballinger ◽  
Leah L. N. Hubbard ◽  
Tracy R. McMillan ◽  
Galen B. Toews ◽  
Marc Peters-Golden ◽  
...  

Impaired host defense post-bone marrow transplant (BMT) is related to overproduction of prostaglandin E2(PGE2) by alveolar macrophages (AMs). We show AMs post-BMT overproduce granulocyte-macrophage colony-stimulating factor (GM-CSF), whereas GM-CSF in lung homogenates is impaired both at baseline and in response to infection post-BMT. Homeostatic regulation of GM-CSF may occur by hematopoietic/structural cell cross talk. To determine whether AM overproduction of GM-CSF influenced immunosuppression post-BMT, we compared mice that received BMT from wild-type donors (control BMT) or mice that received BMT from GM-CSF−/− donors (GM-CSF−/− BMT) with untransplanted mice. GM-CSF−/− BMT mice were less susceptible to pneumonia with Pseudomonas aeruginosa compared with control BMT mice and showed antibacterial responses equal to or better than untransplanted mice. GM-CSF−/− BMT AMs displayed normal phagocytosis and a trend toward enhanced bacterial killing. Surprisingly, AMs from GM-CSF−/− BMT mice overproduced PGE2, but expression of the inhibitory EP2receptor was diminished. As a consequence of decreased EP2receptor expression, we found diminished accumulation of cAMP in response to PGE2stimulation in GM-CSF−/− BMT AMs compared with control BMT AMs. In addition, GM-CSF−/− BMT AMs retained cysteinyl leukotriene production and normal TNF-α response compared with AMs from control BMT mice. GM-CSF−/− BMT neutrophils also showed improved bacterial killing. Although genetic ablation of GM-CSF in hematopoietic cells post-BMT improved host defense, transplantation of wild-type bone marrow into GM-CSF−/− recipients demonstrated that parenchymal cell-derived GM-CSF is necessary for effective innate immune responses post-BMT. These results highlight the complex regulation of GM-CSF and innate immunity post-BMT.


Blood ◽  
1993 ◽  
Vol 81 (9) ◽  
pp. 2452-2459 ◽  
Author(s):  
J Rabinowitz ◽  
WP Petros ◽  
AR Stuart ◽  
WP Peters

Endogenous cytokines are thought to mediate numerous biologic processes and may account for some adverse effects experienced following the administration of recombinant proteins. This study describes the pattern of endogenous cytokine exposure following high-dose chemotherapy. Blood concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), macrophage colony-stimulating factor (M-CSF), and erythropoietin (EPO) were measured by enzyme-linked immunosorbent assay (ELISA) methods in 68 patients receiving the same ablative chemotherapy regimen (cyclophosphamide, cisplatin, carmustine). Patients were grouped according to cellular support (autologous bone marrow [BM] CSF-primed peripheral blood progenitor cells [PBPCs]) and prescribed growth factor (recombinant human granulocyte or granulocyte-macrophage colony-stimulating factor [rHuG- CSF or rHuGM-CSF]). Leukocyte reconstitution was most accelerated in the groups treated with PBPCs and rHuG-CSF. IL-6, M-CSF, and TNF-alpha concentrations were higher in the groups treated with rHuGM-CSF and without PBPCs. Maximal endogenous cytokine concentrations occurred approximately 12 days after BM reinfusion. High concentrations of EPO occurred in patients experiencing significant hypotension despite routine transfusions for hematocrit < 42%. High M-CSF and IL-6 levels were associated with increased platelet transfusion requirements. Concentrations of all four cytokines were significantly higher in patients experiencing renal or hepatic toxicity, with elevations occurring in a predictable sequence and M-CSF elevations occurring first. This report shows that endogenous cytokine concentrations may be influenced by either cellular or CSF support and are associated with differences in platelet reconstitution and organ toxicity.


Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1148-1154 ◽  
Author(s):  
BR Blazar ◽  
MB Widmer ◽  
CC Soderling ◽  
S Gillis ◽  
DA Vallera

Abstract In vivo administration of murine recombinant granulocyte/macrophage colony stimulating factor (rGM-CSF) was evaluated for effects on survival and engraftment in an allogeneic murine bone marrow transplantation (BMT) model involving T-cell depletion of donor marrow. The model provides a high incidence of graft failure/rejection. Recipients of continuous subcutaneous infusions of rGM-CSF had a significant survival advantage when compared with untreated controls. However, a significantly lower incidence of donor cell engraftment was noted. Hematological parameters were not substantially affected. When rGM-CSF was administered intraperitoneally (IP), twice daily injections closely approximated the effects of continuous infusion on survival. Single IP injections were without significant effects on survival or engraftment. These results demonstrate that prolonged frequent in vivo exposure to rGM-CSF can significantly improve survival but significantly decreases donor cell repopulation in recipients of T-cell- depleted histoincompatible marrow grafts.


Blood ◽  
1988 ◽  
Vol 71 (3) ◽  
pp. 758-765 ◽  
Author(s):  
G Kannourakis ◽  
GR Johnson

Abstract Normal human bone marrow mononuclear cells were fractionated by differential adherence, immunomagnetic separation, and fluorescence- activated cell sorting (FACS). The resultant fractionated cells were cultured in semisolid medium to monitor the presence of BFU-E, Mix-CFC, and nonerythroid CFC. Two populations of cells were recovered on the basis of binding by the monoclonal antibody (MoAb) RFB-1. One of these populations contained BFU-E that were stimulated only by erythropoietin (Epo), whereas the second population contained BFU-E responsive to Epo, Epo and recombinant human granulocyte-macrophage colony-stimulating factor (rHGM-CSF), or Epo and human placental-conditioned medium (HPCM). Prior enrichment of clonogenic cells by removal of adherent and Leu-M3+ve, Leu-4+ve, Leu-7+ve, B1+ve, WEMG1+ve, and Glycophorin A+ve cells, followed by FACS fractionation on the basis of RFB-1 binding, consistently resulted in recoveries of BFU-E, Mix-CFC, and nonerythroid CFC of greater than 100% (up to 800%). These procedures also resulted in enrichment of up to 200-fold and frequencies of 1:6 for BFU-E, 1:5 for CFC, and 1:130 for Mix-CFC.


Blood ◽  
1995 ◽  
Vol 86 (7) ◽  
pp. 2526-2533 ◽  
Author(s):  
L Yang ◽  
YC Yang

Abstract Interactions between different cytokines, extracellular matrix components, and various cell types inside the bone marrow microenvironment are believed to play important roles in the regulation of hematopoiesis. We observed that both interleukin-1 (IL-1) and 12-O- tetradecanoylphorbol-13-acetate (TPA) can stimulate the expression of IL-11 and granulocyte-macrophage colony-stimulating factor (GM-CSF) genes in a primate bone marrow stromal fibroblast cell line, PU-34. We also found that IL-1 or TPA-stimulated IL-11 and GM-CSF expression in PU-34 cells can be abolished by heparin, a class of molecules related to extracellular matrix components, glycosaminoglycans. Because the growth inhibitory signals provided by extracellular factors were less understood, the mechanisms of heparin inhibition of IL-11 and GM-CSF gene expression were further investigated. Our data demonstrate for the first time that heparin did not alter the transcription of endogenous IL-11 and GM-CSF genes or an exogenous IL-11 promoter construct containing an AP-1 sequence. Instead, heparin facilitated the degradation of the corresponding mRNAs. Through RNA gel shift assays, heparin-mediated mRNA destabilization was tentatively linked to its competition for mRNA binding proteins both in the cell-free system and in intact cells. Collectively, our findings suggest that varying degrees of heparin inhibition may provide a novel mechanism for the regulation of cytokine expression during the growth and differentiation of different lineages of hematopoietic cells.


Sign in / Sign up

Export Citation Format

Share Document