Background: TREM2 is a DAP12-coupled receptor associated with neurodegenerative diseases. Results: Co-expression of DAP12 increased the level of TREM2 C-terminal fragment (TREM2-CTF) which suppressed the release of pro-inflammatory cytokines. Conclusion: A major function of DAP12 is to stabilize TREM2-CTF, which regulates inflammatory responses in microglia. Significance: Our studies unraveled a novel function of DAP12 and provided new link between TREM2/DAP12 complexes and neuroinflammation.

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BackgroundDuring myocardial ischemia/reperfusion (MI/R) injury, there is extensive release of immunogenic metabolites that activate cells of the innate immune system. These include ATP and AMP, which upregulate chemotaxis, migration, and effector function of early infiltrating inflammatory cells. These cells subsequently drive further tissue devitalization. Mesenchymal stromal cells (MSCs) are a potential treatment modality for MI/R because of their powerful anti‐inflammatory capabilities; however, the manner in which they regulate the acute inflammatory milieu requires further elucidation. CD73, an ecto‐5′‐nucleotidase, may be critical in regulating inflammation by converting pro‐inflammatory AMP to anti‐inflammatory adenosine. We hypothesized that MSC‐mediated conversion of AMP into adenosine reduces inflammation in early MI/R, favoring a micro‐environment that attenuates excessive innate immune cell activation and facilitates earlier cardiac recovery.Methods and ResultsAdult rats were subjected to 30 minutes of MI/R injury. MSCs were encapsulated within a hydrogel vehicle and implanted onto the myocardium. A subset of MSCs were pretreated with the CD73 inhibitor, α,β‐methylene adenosine diphosphate, before implantation. Using liquid chromatography/mass spectrometry, we found that MSCs increase myocardial adenosine availability following injury via CD73 activity. MSCs also reduce innate immune cell infiltration as measured by flow cytometry, and hydrogen peroxide formation as measured by Amplex Red assay. These effects were dependent on MSC‐mediated CD73 activity. Finally, through echocardiography we found that CD73 activity on MSCs was critical to optimal protection of cardiac function following MI/R injury.Conclusions MSC‐mediated conversion of AMP to adenosine by CD73 exerts a powerful anti‐inflammatory effect critical for cardiac recovery following MI/R injury.

Ubiquitin carboxyl-terminal hydrolase 37 (UCH37) is a member of deubiquitinating enzymes. It can suppress protein degradation through disassembling polyubiquitin from the distal subunit of the chain. The aim of this study was to assess the value of UCH37 in predicting tumor recurrence after curative resection in epithelial ovarian cancer (EOC) patients. In this study, the expression level of UCH37 in 5 paired EOC and normal tissue was tested by Western blot. And the association of UCH37 expression and prognostic value was analyzed in 100 tumor specimens from EOC patients, who underwent curative resection between 2003 and 2011. We found that UCH37 was up-regulated in most of the tumor tissue and high expression of UCH37 was an independent significant predictor associated with the poor outcome and recurrence of EOC (p=0.0037 and p=0.0042 in overall and disease-free survival, respectively), especially in the advanced stage of EOC (p=0.0106 and p=0.0115 in overall and disease-free survival, respectively), and may become a novel predictor for prognosis of EOC patients after curative resection. Our data suggest for the first time that UCH37 overexpression is associated with advanced tumor progression and poor clinical outcome of EOC patients and may help physicians make informed decisions regarding adjuvant treatment following curative resection.