The Effect of CD226 on the Balance between Inflammatory Monocytes and Small Peritoneal Macrophages in Mouse Ulcerative Colitis

CD226 promotes renal fibrosis by regulating macrophage activation and migration

It has been found that CD226 plays an important role in regulating macrophage function, but its expression and function in macrophages during renal fibrogenesis have not been studied. Our data demonstrated that CD226 expression in macrophages was obviously upregulated in the unilateral ureteral obstruction model, while CD226 deficiency attenuated collagen deposition in renal interstitium along with fewer M1 within renal cortex and renal medulla and a lower level of proinflammatory factors compared to that of control littermates. Further studies demonstrated that Cd226-/- bone marrow-derived macrophages transferring could significantly reduce the tubular injury, collagen deposition, and proinflammatory cytokine secretion compared with that of Cd226+/+ bone marrow-derived macrophages transferring in the unilateral ureteral obstruction model. Mechanistic investigations revealed that CD226 promoted proinflammatory M1 macrophage accumulation in the kidney via suppressing KLF4 expression in macrophages. Therefore, our results uncovered a pathogenic role of CD226 during the development of chronic kidney disease by promoting monocyte infiltration from peripheral blood into the kidney and enhancing macrophage activation toward the inflammatory phenotype by suppressing KLF4 expression.

Simulated microgravity increases CD226+ Lin- CD117- Sca1+ mesenchymal stem cells in mice

Microgravity is one of the most common causes counting for the bone loss. Mesenchymal stem cells (MSCs) contribute greatly to the differentiation and function of bone related cells. The development of novel MSCs biomarkers is critical for implementing effective therapies for microgravity induced bone loss. We aimed to find the new molecules involved in the differentiation and function of MSCs in mouse simulated microgravity model. We found CD226 was preferentially expressed on a subset of MSCs. Simulation of microgravity treatment significantly increased the proportion of CD226+ Lin- CD117- Sca1+ MSCs. The CD226+ MSCs produced higher IL-6, M-CSF, RANKL and lower CD200 expression, and promoted osteoclast differentiation. This study provides pivotal information to understand the role of CD226 in MSCs, and inspires new ideas for prevention of bone loss related diseases.

Immunosuppressive M2 TAMs represent a promising target population to enhance phagocytosis of ovarian cancer cells in vitro

Introduction

Tumor-associated macrophages (TAMs) represent an important cell population within the tumor microenvironment, but little is known about the phenotype and function of these cells. The present study aims to characterize macrophages in high-grade serous ovarian cancer (HGSOC).

Methods

Phenotype and expression of co-regulatory markers were assessed on TAMs derived from malignant ascites (MA) or peripheral blood (PB) by multiparametric flow cytometry. Samples were obtained from HGSOC patients (n=29) and healthy donors (HDs, n=16). Additional expression analysis was performed by RNAseq (n=192). Correlation with clinically relevant parameters was conducted and validated by a second patient cohort (n=517). Finally, the role of TIGIT in repolarization and phagocytosis was investigated in vitro.

Results

Expression of the M2-associated receptors CD163, CD204, and CD206, as well as of the co-regulatory receptors TIGIT, CD226, TIM-3, and LAG-3 was significantly more frequent on macrophages in HGSOC than in HDs. CD39 and CD73 were broadly expressed on (mainly M2) macrophages, but without a clear clustering in HGSOC. CD163 mRNA levels were higher in TAMs from patients with residual tumor mass after surgery and associated with a shorter overall survival. In addition, TIGIT expression was associated with a higher tumor grading, indicating a prognostic relevance of M2 infiltration in HGSOC. TIGIT blockade significantly reduced the frequency of M2 macrophages. Moreover, combined blockade of TIGIT and CD47 significantly increased phagocytosis of ovarian cancer cells by TAMs in comparison to a single blockade of CD47.

Conclusion

Combined blockade of TIGIT and CD47 represents a promising approach to enhance anti-CD47-facilitated phagocytosis.