Project description:We report the single cell transcriptome of CD45+ cells from the livers of bone marrow chimeric wildtype mice with NASH that had previously been transplanted with bone marrow from TREM2-deficient or wildtype littermate mice. We show that hematopoietic TREM2 deficiency is associated with alterations in the hepatic immune cell composition in the context of NASH.
Project description:Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease that ranges from simple steatosis, to inflammatory form non-alcoholic steatohepatitis (NASH), cirrhosis, and up to hepatocellular carcinoma. While NASH usually takes decades to develop at a rate of one stage per seven years, in the case of post-trasplant NASH (pt-NASH) develops fibrosis much more rapidly, with almost 50% of liver transplant recipients presenting stage 3 fibrosis by 5 years post-transplant. Archived fresh-frozen transplanted liver biopsy samples from four liver biopsy samples with evidence of NASH (2 recurrent and 2 de novo), two with simple steatosis (both de novo), and five with normal histology as controls had their transcriptome sequenced in two batches for deeper coverage.
Project description:Macrophages are exquisitely capable of sensing danger-associated molecular patterns (DAMPs) and orchestrating inflammatory response during tissue injury. Nonalcoholic steatohepatitis (NASH) represents an advanced stage of metabolic fatty liver disease that increases the risk for cirrhosis and liver cancer. Pathogenic mechanisms of NASH center on hepatocyte injury and the ensuing immune response within the liver microenvironment. However, the nature of DAMPs released by injured hepatocytes and how they shape the liver immune milieu remain largely unknown. Here we show that lipid droplets (LDs) released by injured fatty hepatocytes provide a potent signal that triggers monocyte infiltration and maturation into Trem2+ macrophages, recently described as NASH-associated macrophages (NAMs) or lipid- associated macrophages. LD treatment exacerbated liver injury in mice with diet-induced NASH. We identified Membrane spanning 4-domains a7 (Ms4a7) as a NAM-specific pathogenic factor that was strongly induced in mouse and human NASH. Ms4a7 inactivation ameliorated key aspects of diet-induced NASH pathologies in mice. At the mechanistic level, Ms4a7 physically interacts with NLR family pyrin domain containing 3 (NLRP3) and is required for endosomal NLRP3 inflammasome activation. These findings illustrate a crucial role of Ms4a7 in driving pro-inflammatory signaling in NASH liver. Surprisingly, LD treatments attenuated Ms4a7 expression and NLRP3 inflammasome activation in cultured macrophages. As such, LDs serve as a DAMP signal that balances the induction of Trem2+ macrophages and NLRP3 inflammasome activation in NASH liver
Project description:Triggering receptor expressed on myeloid cells 2 (Trem2) has been shown to be immunosuppressive in cancer and increased in obese adipose tissue. We utilized high fat and low fat diet to generate lean, obese, and weight loss mice in Trem2 wild-type (Trem2+/+) and Trem2 deficient (Trem2-/-) conditions. Once obesity and weight loss were established, mice were injected with E0771 breast cancer cells and tumors were allowed to grow for 4 weeks. We wanted to better understand the immune landscape of both the tumor and the surrounding adjacent mammary adipose tissue (mAT). Therefore, the CD45+ immune cells from both the tumor and tumor-adjacent mAT were isolated and sequenced using single-cell RNA sequencing and V(D)J sequencing.
Project description:Exploration of proteome differences between CD45+ and CD45- cell types in renal cell carcinoma tumors and normal adjacent tissue patient samples.
Project description:We examined the role of TREM2 on microglia responses to amyloid-beta deposition in a mouse model of Alzheimer's disease Microglia were FACS-purified from 8.5 month old WT, Trem2-/-, 5XFAD, and Trem2-/- 5XFAD mice
Project description:We examined the role of TREM2 on microglia responses to demyelination Microglia were FACS-purified from WT or Trem2-/- mice fed with 0.2% cuprizone diet.