Although much progress has been made recently in revealing the heterogeneity of the thymic stromal components, the molecular programs of cell lineage divergency and temporal dynamics of thymic epithelial cell (TEC) development are largely elusive. Here, we constructed a single-cell transcriptional landscape of non-hematopoietic cells from mouse thymus spanning embryonic to adult stages, producing transcriptomes of 30,959 TECs. We resolved the transcriptional heterogeneity of developing TECs and highlighted the molecular nature of early TEC lineage determination and cortico-medullary thymic epithelial cell lineage divergency. We further characterized the differentiation dynamics of TECs by clarification of molecularly distinct cell states in the thymus developing trajectory. We also identified a population of Bpifa1+ Plet1+ mTECs that was preserved during thymus organogenesis and highly expressed tissue-resident adult stem cell markers. Finally, we highlighted the expression of Aire-dependent tissue-restricted antigens mainly in Aire+ Csn2+ mTECs and Spink5+ Dmkn+ mTECs in postnatal thymus. Overall, our data provided a comprehensive characterization of cell lineage differentiation, maturation, and temporal dynamics of thymic epithelial cells during thymus organogenesis.

<abstract> <p>PTPRD plays an indispensable role in the occurrence of multiple tumors. However, pan-cancer analysis is unavailable. The purpose of this research was to preliminarily study its prognostic landscape across various tumors and investigate its relationship with immunotherapy. We exhibited the expression profile, survival analysis, and genomic alterations of PTPRD based on the TIMER, GEPIA, UALCAN, PrognoScan and cBioPortal database. The frequency of PTPRD mutation and its correlation with response to immunotherapy were evaluated using the cBioPortal database. The relationship between PTPRD and immune-cell infiltration was analyzed by the TIMER and TISIDB databases. A protein interaction network was constructed by the STRING database. GO and KEGG enrichment analysis was executed by the Metascape database. A correlation between PTPRD expression and prognosis was found in various cancers. Aberrant PTPRD expression was closely related to immune infiltration. In non-small cell lung cancer and melanoma, patients with PTPRD mutations had better overall survival with immune checkpoint inhibitors, and these patients had higher TMB scores. PTPRD mutation was involved in numerous biological processes, including immunological signaling pathways. A PTPRD protein interaction network was constructed, and genes that interacted with PTPRD were identified. Functional enrichment analysis demonstrated that a variety of GO biological processes and KEGG pathways associated with PTPRD were involved in the therapeutic mechanisms. These results revealed that PTPRD might function as a biomarker for prognosis and immune infiltration in cancers, throwing new light on cancer therapeutics.</p> </abstract>

Background Cyclooxygenase‐2 (COX‐2) is an inducible enzyme with catalytic activity for biosynthesis of prostaglandins which are the key mediators of inflammation. COX‐2 is also the therapeutic target for widely used non‐steroidal anti‐inflammatory drugs (NSAIDs). However, the involvement of COX‐2 in xenotransplantation (eg, pig‐to‐non‐human primate) remains poorly recognized. Methods We investigated the mechanisms that regulate COX‐2 expression and the effects of COX‐2 on porcine aortic endothelial cell (PAEC) viability using in vitro pig‐to‐primate xenotransplantation model and in vivo pig‐to‐mouse cellular transplant model. Regulation of COX‐2 expression was assessed by real‐time quantitative polymerase chain reaction (qPCR) and Western blotting. The effects of inhibition or downregulation of COX‐2 on PAEC viability were assessed by propidium iodide (PI)‐Annexin V staining and Cell Counting Kit‐8 assay. Results Human serum triggered robust COX‐2 expression in PAECs in a dose‐ and time‐dependent manner. Induction of COX‐2 expression by human serum was partially through activation of both canonical and non‐canonical nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κb) signaling and increasing intracellular calcium. Cytokines like tumor necrosis factor alpha (TNF‐α), interleukin 1 beta (IL‐1β), IL‐17, were able to induce COX‐2 expression. Selective inhibition of COX‐2 by celecoxib dramatically decreased PAEC death in vitro and in vivo as defined by propidium iodide (PI)‐Annexin V staining. Consistently, downregulation of COX‐2 expression by NF‐κb inhibitors or calcium chelator BAPTA decreased human serum‐induced PAEC death as well. Silencing of COX‐2 expression by small interfering RNA (siRNA) protected PAEC viability when transplanted under kidney capsule of C57BL/6 mice. Conclusions Taken together, our data suggest that COX‐2 is highly induced in PAECs by xenogenic serum and associated with human antibody‐mediated complement‐dependent cytotoxicity. COX‐2 might be a potential therapeutic target to improve xenotransplantation.

Background: PTPRD plays an indispensable role in the occurrence of multiple tumors. However, pan-cancer analysis is unavailable. The purpose of this research was to investigate the relationship between PTPRD and immunity and describe its prognostic landscape across various tumors. Methods: We explored expression profile, survival analysis, and genomic alterations of PTPRD based on the TIMER, GEPIA, UALCAN, PrognoScan, and cBioPortal database. The frequency of PTPRD mutation and its correlation with response to immunotherapy were evaluated using the cBioPortal database. The relationship between PTPRD and immune-cell infiltration was analyzed by the TIMER and TISIDB databases. A protein interaction network was constructed by the STRING database. GO and KEGG enrichment analysis was executed by the Metascape database.Results: A significant correlation between PTPRD expression and prognosis was found in various cancers. Aberrant PRPRD expression was closely related to immune infiltration. Importantly, the patients who harbored PTPRD mutation and received immune checkpoint inhibitors had worse overall survival, especially in non-small cell lung cancer and melanoma, and had a higher TMB score. Moreover, PTPRD mutation was involved in numerous biological processes, including immunological signaling pathways. Additionally, a PTPRD protein interaction network was constructed, and genes that interacted with PTPRD were identified. Functional enrichment analysis demonstrated that a variety of GO biological processes and KEGG pathways of PTPRD were primarily involved in the therapeutic mechanisms. Conclusions: These results revealed that PRPRD might function as a biomarker for prognosis and immune infiltration in cancers, throwing new light on cancer therapeutics.

Osteoarthritis (OA) is a degenerative disease of joints commonly occurring in the elderly and middleaged people. This study aimed to investigate the effect of recombinant human endostatin (rhEndo) on OA and the levels of MMP-13, IL-1 and IL-6 in the synovial fluid in osteoarthritis rats. OA models were made by injecting 4% papain into the knee joint cavity of rats once every three days for three times. The models were then injected subcutaneously with rhEndo and examined six weeks later for the Mankin scores and levels of MMP-13, IL-1 and IL-6 using ELISA. Compared with control, the Mankin score as well as the levels of IL-1, IL-6 and MMP-13 were significantly increased in the models (0.30 vs. 5.80, 1.12 vs. 12.84 pg/ mL, 12.22 vs. 43.82 pg/ mL and 0.23 vs. 26.31 ng/ mL). Following treatment with 4 mg/kg rhEndo, the Mankin score in model decreased to 0.90, meanwhile, the levels of IL-1, IL-6 and MMP-13 decreased significantly to 0.79 pg/ mL, 2.89 pg/mL and 1.17 ng/mL, respectively, in a dose dependent manner. Therefore, rhEndo can alleviate osteoarthritis by reducing MMP-13, IL-1 and IL-6 expression in rats.