scholarly journals Evidence that Contamination by Lipopolysaccharide Confounds in Vitro Studies of Adiponectin Activity in Bone

Endocrinology ◽  
2012 ◽  
Vol 153 (5) ◽  
pp. 2076-2081 ◽  
Author(s):  
Dorit Naot ◽  
Garry A Williams ◽  
Jian-ming Lin ◽  
Jillian Cornish ◽  
Andrew Grey

Adiponectin, a hormone produced and secreted from adipose tissue, circulates at levels that are inversely related to visceral fat mass and bone mineral density. Adiponectin receptors are expressed in bone cells, and several studies have shown that adiponectin affects bone phenotype and might play a role in the cross talk between fat and bone tissues. In the current study, we determined global changes in gene expression induced by adiponectin in mouse bone marrow cells, in order to identify the molecular mechanisms that mediate adiponectin's effect to inhibit osteoclast differentiation in these cultures. The gene signature that was produced by microarray analysis was very similar to a signature produced by activation of type I interferons (IFN), and we therefore tested the hypothesis that the adiponectin preparation, although marketed as “lipopolysaccharide (LPS) free”, was contaminated with LPS that induced an IFN response in the bone marrow cells. Heat inactivation of the adiponectin preparation and the use of small interfering RNA to knockdown the AdipoR1 receptor had not diminished the activity of the adiponectin preparation to induce the IFN target genes Ccl5 and Irf7. Thus, the changes in gene expression determined in the bone marrow cultures are likely to be the result of a combination of adiponectin and LPS effects. Our study suggests that the purity of commercially available proteins needs to be verified and that experimental results of adiponectin activity in vitro should be interpreted cautiously.

1971 ◽  
Vol 134 (3) ◽  
pp. 786-800 ◽  
Author(s):  
Myra Small ◽  
Nathan Trainin

The hypothesis that cells located in mouse bone marrow can acquire immunological competence by a process that involves interaction with a noncellular component of the thymus was tested using an in vitro assay of graft-versus-host reactivity as a criterion of cell competence. When suspensions of C57BL bone marrow cells were incubated in thymus extract and injected into mice incapable of inducing a response in the graft-versus-host assay as a result of neonatal thymectomy, or adult thymectomy plus irradiation, or because of genetic similarity with the (C3H x C57BL)F1 tissue used for challenge in the assay, competent cells were recovered from the spleens of the injected mice. The reactive cells were shown to be of bone marrow origin since immune reactivity was related to the genetic makeup of the bone marrow cells rather than that of the intermediate recipients. A thymic factor was involved in the process leading to immune reactivity by these cells, as bone marrow cells incubated in xenogeneic or syngeneic thymic extracts induced a graft-versus-host response after passage through nonresponsive mice, whereas incubation of bone marrow cells in xenogeneic lymph node or spleen extracts or in culture medium only did not lead to subsequent reactivity. Participation of peripheral lymphoid tissue seemed essential in this process since bone marrow cells tested directly after exposure to thymic extract failed to induce a graft-versus-host response. C57BL bone marrow cells exposed to thymus extract and cultured together with fragments of (C3H x C57BL)F1 spleen tissue in vitro were competent to induce a graft-versus-host response; thus, these components would seem to be sufficient as well as necessary for the immunodifferentiation process leading to graft-versus-host activity. It is concluded that one step in the process by which bone marrow cells acquire competence vis-a-vis the graft-versus-host response depends upon a thymic agent that is noncellular and extractable, and that another stage in this process is under the influence of components found within the peripheral lymphoid tissue environment. It is suggested that differentiation of precursor cells to competence could occur by progressive development of the cells in separate compartments of the lymphoid system.


Author(s):  
F. M. Gao ◽  
X. L. Li ◽  
M. J. Qian ◽  
W. H. Wang ◽  
F. Q. Qi ◽  
...  

2011 ◽  
Vol 106 (08) ◽  
pp. 337-343 ◽  
Author(s):  
Jianhui Wang ◽  
Zanhua Yi ◽  
Shiyang Wang ◽  
Zongdong Li

SummaryThrombocytopenia is a common feature of myelodysplastic syndromes (MDS). 5-aza-2’-deoxycytidine (decitabine) has been used to treat MDS with an approximately 20% response rate in thrombocytopenia. However, the mechanism of how decitabine increases platelet count is not clear. In this study, we investigated the effect of decitabine on megakaryocyte maturation and platelet release in the mouse. The effect of decitabine on megakaryocyte maturation was studied in an in vitro megakaryocyte differentiation model utilising mouse bone marrow cells and mouse megakaryoblastic cell line L8057. Decitabine (2.5 μM) is able to induce L8057 cells to differentiate into a megakaryocyte-like polyploidy cells with positive markers of acetylcholinesterase and αIIb integrin (CD41). Higher expression of αIIb integrin was also found in primary mouse bone marrow cells and human cord blood CD34+ cells cultured with both thrombopoietin and decitabine as compared to thrombopoietin alone. In addition, we noted a 30% platelet count increase in Balb/c mice 12 hours after the injection of decitabine at a clinically relevant dose (15 mg/m2), suggesting a rapid platelet release from the spleen or bone marrow. Our data suggest that decitabine increases platelet counts by enhancing platelet release and megakaryocyte maturation.


2008 ◽  
Vol 104 (1) ◽  
pp. 295-303 ◽  
Author(s):  
Hee-Young Yang ◽  
Dong Kee Jeong ◽  
Seok-Ho Kim ◽  
Kyoung-Jin Chung ◽  
Eun-Jin Cho ◽  
...  

1994 ◽  
Vol 29 (3) ◽  
pp. 631-634 ◽  
Author(s):  
Masako Nose ◽  
Yoshiro Aoki ◽  
Yoshiko Kawase ◽  
Gen Suzuki ◽  
Makoto Akashi ◽  
...  

2022 ◽  
Author(s):  
Ines Borrego ◽  
Aurelien FROBERT ◽  
Guillaume AJALBERT ◽  
Jeremy VALENTIN ◽  
Cyrielle KALTENRIEDER ◽  
...  

Interactions between macrophages, cardiac cells and the extracellular matrix are crucial for cardiac repair following myocardial infarction (MI). The paracrine effects of cell-based treatments of MI might modulate these interactions and impact cardiac repair. The immunomodulatory capacity of the therapeutic cells is therefore of interest and could be modulated by the use of biomaterials. We first showed that bone marrow cells (BMC) associated with fibrin could treat MI. Then, we interrogated the influence of fibrin, as a biologically active scaffold, on the secretome of BMC and the impact of their association on macrophage fate and cardiomyoblast proliferation. Methods: In vivo, two weeks post-MI, rats were treated with epicardial implantation of BMC and fibrin or sham-operated. High-resolution echocardiography was performed to evaluate the heart function and structure changes after 4 weeeks. Histology and immunostaining were performed on harvested hearts. In vitro, BMC were first primed with fibrin. Second, non-polarized macrophages were differentiated toward either pro-inflammatory or anti-inflammatory phenotypes and stimulated with the conditioned medium of fibrin-primed BMC (F-BMC). Proteomic, cytokine levels quantification, and RT-PCR were performed. EdU incorporation and real-time cell analysis assessed cell proliferation. Results: The epicardial implantation of fibrin and BMC reduced the loss of cardiac function induced by MI, increased wall thickness and prevented the fibrotic scar expansion. After 4 and 12 weeks, the infarct content of CD68+ and CD206+ was similar in control and treated animals. In vitro, we showed that fibrin profoundly influenced the gene expression and the secretome of BMC, simultaneously upregulating both pro- and anti-inflammatory mediators. Furthermore, the conditioned medium from F-BMC significantly increased the proliferation of macrophages in a subsets dependent manner and modulated their gene expression and cytokines secretion. For instance, F-BMC significantly downregulated the expression of Nos2, Il6 and Ccl2/Mcp1 while Arg1, Tgfb and IL10 were upregulated. Interestingly, macrophages educated by F-BMC increased cardiomyoblast proliferation. In conclusion, our study provides evidence that BMC/fibrin-based treatment lowered the infarct extent and improved cardiac function. The macrophage content was unmodified when measured at a chronic stage. Nevertheless, acutely and in vitro, the F-BMC secretome promotes an anti-inflammatory response that stimulates cardiac cell growth. Finally, our study emphases the acute impact of F-BMC educated macrophages on cardiac cell fate.


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