Protein Tyrosine Phosphatase PTPRO Signaling Couples Metabolic States to Control the Development of Granulocyte Progenitor Cells

Sirtuin 2 regulates neutrophil functions through NAD+ synthesis pathway in virus infection

Neutrophils play an important role in antiviral immunity, but the underlying mechanisms remain unclear. Here, we found that SIRT2 deficiency inhibited the infiltration of neutrophils, as well as the secretion of inflammatory cytokines and the formation of neutrophil extracellular traps (NETs), ameliorating disease symptoms during acute respiratory virus infection. Mechanistically, SIRT2 deficiency upregulates quinolinic acid (QA)-producing enzyme 3-hydroxyanthranilate oxygenase (3-HAO) and leads to expression of quinolinate phosphoribosyltransferase (QPRT), which promotes the synthesis of QA for NAD+ and limits viral infection when de novo NAD+ synthesis is blocked. Tryptophan-2,3-oxygenase expressed in epithelial cells metabolizes tryptophan to produce kynurenine and 3-hydroxyaminobenzoic acid, which is a source of intracellular QA in neutrophils. Thus, our findings reveal a previously unrecognized QPRT-mediated switch in NAD+ metabolism by exploiting neutrophil-derived QA as an alternative source of replenishing intracellular NAD+ pools induced by SIRT2 to regulate neutrophil functions during virus infection, with implications for future immunotherapy approaches.

Comprehensively Analyze the Prognosis Significance and Immune Implication of PTPRO in Lung Adenocarcinoma

Immunotherapy for lung adenocarcinoma (LUAD) is considered to be a promising treatment option, but only a minority of patients benefit from it. Therefore, it is essential to clarify the regulation mechanism of the tumor immune microenvironment (TIM) of the LUAD. Receptor-type protein tyrosine phosphatase (PTPRO) has been shown to be a tumor suppressor in a variety of tumor; however, its role in LUAD has never been reported. In this study, we first found that PTPRO was lowly expressed in LUAD and positively correlated with patient prognosis. Next, we investigated the relationship between PTPRO and clinical characteristics, and the results showed that gender, age, T, and stage were closely related to the expression level of PTPRO. Moreover, we performed univariate and multivariate analyses, and the results revealed that PTPRO was a protective factor for LUAD. By constructing a nomogram based on the expression level of PTPRO and various clinical characteristics, it was proved that the nomogram has a good predictive capacity. Furthermore, we analyzed the coexpression network of PTPRO through multiple databases and performed GO and KEGG enrichment analyses. The results demonstrated that PTPRO was involved in the regulation of multiple immune pathways. In addition, we analyzed whether PTPRO expression of LUAD regulate immune cell infiltration and the results demonstrated that PTPRO was closely related to the infiltration of various immune cells. Finally, we predicted LUAD sensitivity to chemotherapeutics and response to immunotherapy by PTPRO expression levels. The results showed that PTPRO expression level affect the sensitivity of various chemotherapeutic drugs and may be involved in the efficacy of immunotherapy. These results we obtained suggested that PTPRO is closely related to the prognosis and TIM of LUAD, which may be a potential immunotherapeutic target for LUAD.