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Allograft rejection is a common immunological feature in renal transplantation and is associated with reduced graft survival. A mouse renal allograft rejection model was induced and single-cell RNA sequencing (scRNA-seq) data of CD45+leukocytes in kidney allografts on days 7 (D7) and 15 (D15) after operation was analyzed to reveal a full immunological profiling. We identified 20 immune cell types among 10,921 leukocytes. Macrophages and CD8+T cells constituted the main populations on both timepoints. In the process from acute rejection (AR) towards chronic rejection (CR), the proportion of proliferating and naïve CD8+T cells dropped significantly. Both B cells and neutrophils decreased by about 3 folds. On the contrary, the proportion of macrophages and dendritic cells (DCs) increased significantly, especially by about a 4.5-fold increase in Ly6cloMrc1+macrophages and 2.6 folds increase in Ly6cloEar2+macrophages. Moreover, myeloid cells harbored the richest ligand and receptor (LR) pairs with other cells, particularly for chemokine ligands such as Cxcl9, Cxcl10, Cxcl16 and Yars. However, macrophages with weak response to interferon gamma (IFNg) contributed to rejection chronicization. To conclude, reduction in CD8 T cells, B cells and neutrophils while increasing in Ly6cloMrc1+macrophages and Ly6cloEar2+macrophages, may contribute significantly to the progress from AR towards CR.

Background & Aims: The role of macrophages in fibrosing steatohepatitis is largely unclear. We characterized the origin and molecular mechanisms of macrophages and its targeted therapy in fibrosing steatohepatitis. Methods: Fibrosing steatohepatitis was established in Alms1 mutant (foz/foz) and C57BL/6 wildtype mice fed high-fat/high-cholesterol (HFHC) or methionine-and choline-deficient (MCD) diet. Bone marrow transplantation (BMT) was performed to track the macrophage origin in fibrosing steatohepatitis. Macrophages were depleted by liposomal clodronate. Primary macrophages were isolated from bone marrow for adoptive transfer into mice. Results: Macrophage infiltration is significantly induced in two mouse models of fibrosing steatohepatitis and human NASH-fibrosis patients. Bone marrow-derived macrophages (BMMs) contribute to the hepatic macrophage accumulation in experimental fibrosing steatohepatitis. Hepatic BMMs depletion by liposomal clodronate significantly attenuated fibrosing steatohepatitis. This effect was associated with reduced hepatic stellate cell (HSC) activation, collagen deposition and hepatic expression of key pro-fibrotic factors (TIMP1, TIMP2 and TGFβ1) and endoplasmic reticulum (ER) stress markers (GRP78, IRE1α and PDI). Conversely, adoptive transfer of BMMs significantly aggravated fibrosing steatohepatitis. Moreover, macrophage conditioned medium directly promoted the phenotypic transition of primary quiescent HSCs to activated HSCs; enhanced activation and proliferation (P

Disease associated gene deficient embryonic stem cells can serve as valuable in vitro models to study disease mechanisms and screen drugs. Smad3 mediated TGF-β/Activin/Nodal signaling plays important roles in many biological processes. Despite numerous studies regarding Smad3 function, the role of Smad3 in mouse ES cells is not well studied. To understand the function of Smad3 in mouse ES cells, we derived Smad3−/− ES cells and wild type ES cells. Smad3−/− ES cells display no defect on self-renewal. They express similar level of pluripotent genes and lineage genes compared to wild type ES cells. However, Smad3 ablation results in transient difference in germ layer marker expression during embryoid body formation. Mesoderm lineage marker expression is significantly reduced in the embryoid body formed by Smad3−/− ES cells compared to wild type ES cells. Intriguingly, subcutaneous injection of Smad3−/− ES cells into nude mice leads to formation of malignant immature teratomas, whilst wild type ES cells tend to form mature teratomas. Smad3−/− ES cell formed teratomas can therefore provide a new model for the study of the mechanism of malignant teratomas.