While B cells play a significant role in the onset of type-1 diabetes (T1D), little is know about their role in those early stages. Thus, to gain new insights into the role of B cells in T1D, we converted a physiological early pancreas-infiltrating B cell into a novel BCR mouse model using Somatic Cell Nuclear Transfer (SCNT). Strikingly, SCNT-derived B1411 model displayed neither developmental block nor anergy. Instead, B1411 underwent spontaneous germinal center reactions. Without T cell help, B1411-Rag1 −/− was capable of forming peri-/intra-pancreatic lymph nodes, and undergoing class-switching. RNA-Seq analysis identified 93 differentially expressed genes in B1411 compared to WT B cells, including Irf7, Usp18, and Mda5 that had been linked to a potential viral etiology of T1D. We also found various members of the oligoadenylate synthase (OAS) family to be enriched in B1411, such as Oas1, which had recently also been linked to T1D. Strikingly, when challenged with glucose B1411-Rag1 −/− mice displayed impaired glucose tolerance.
Nonalcoholic fatty liver disease (NAFLD) is one of the leading causes of liver disease worldwide.1 Animal models are widely used to investigate the mechanisms of fatty liver disease, but they do not faithfully represent NAFLD in humans.2 Thus, there is strong interest in studying NAFLD pathogenesis directly in humans whenever possible. One strategy that is gaining momentum is to utilize iPSC-derived hepatocytes from individual human subjects in complex cell/organ platforms with the goal of reproducing a NAFLD-like state in vitro.3-6 Our group has taken a different approach, positing that iPSC-Heps from a population of NAFLD patients would provide independent insight into the human disease. In this study we generated iPSCs and iPSC-Heps from a well-defined cohort of NAFLD patients. Our objective was to determine whether as a group, in the absence of any metabolic challenge, they exhibit common disease-specific signatures that are distinct from healthy controls.
Using epigenetic reprogramming through Somatic Cell Nuclear Transfer, we developed two regulatory T cell (Treg) models, T138 (Ku M., et al., PNAS 2016) and T143 (Ku M., et al., JACI 2018). While both Treg models were thymically derived, T143 displayed characteristics of agonist-selection (aTreg), which had been postulated for all Treg cells. However, T138 was quite distinct with a higher degree of interaction between TCR beta-chain and MHC-II rather than TCR and agonist. We refer to as T138 as natural-occurring Treg cell (nTreg). Strikingly, we identified FoxP3-negative T cells expressing the same TCR as nTreg and aTreg. Especially, FoxP3-negative T cells isolated from T138 were heavily poised in their ability to differentiate into FoxP3-expressing cells rather than Th1-differentation. In order to further identify new transcription factors that mediated this epigenetically poised state in FoxP3-negative T138 (pre-nTreg) cells and to identify accessible promoters and enhancers that are associated with the pro-FoxP3 poised state, we performed ATAC-Seq (assay for transposase-accessible chromatin with high-throughput sequencing). We identified several loci that are more accessible in pre-nTreg cells than in wild-type (WT) cells. Motif analysis revealed enrichment of several lineage-determining transcription factor binding motifs, such as Atf3. Strikingly, transcriptomic analysis demonstrated that Atf3 is specifically expressed in T138 and not in WT. Interestingly; it has previously been shown that the FoxP3-locus contains an Atf-binding site, suggesting an important link of pre-nTreg transcriptional programs to its development into nTreg. Since ATAC-Seq signals show similar enrichment at both active and poised (bivalently-marked by both H3K4me2 and H3K27me3 marks) promoters, we performed H3K4me2 and H3K27me3 chromatin-immunoprecipitation followed by high-throughput sequencing (ChIP-Seq) to further identify poised promoters, which gear e.g. pre-nTreg towards a FoxP3+ cellular fate. In order to identify unique phosphorylation sites during activation of pre-nTreg and nTreg cells, we analyzed the phospho-proteome. We identified several differential phosphorylated peptides. Particularly, we found about 100 peptides uniquely phosphorylated in FoxP3- pre-nTreg cells. Together with the transcriptional analysis this clearly demonstrates the unique characteristics of this novel pre-nTreg population. Several mechanisms had been shown to mediate immune regulatory function of Treg cells. Strikingly, we identified Ctla4 and Lag3 to be differentially expressed in T138, T143 and the Treg pool in WT mice. This is of particular interest since, e.g. CTLA4 is currently being explored for immunotherapy. Differential expression of Ctla4 provides evidence for selective modifications of a Treg subset through anti-CTLA4 treatment. Our data supports the concept that anti-CTLA4 treatment might function through targeting of a tumor-infiltrating Treg subset rather than check point inhibition. Taken together our multiomics and functional data on Treg cells clearly demonstrated the existence of distinct Treg subsets, which has major implications in better understanding disease mechanisms and in devising new future therapies. Disclosures Sabouri-Ghomi: Fate Therapeutics: Employment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.