Seleno-detergent MAD phasing of leukotriene C4 synthase in complex with dodecyl-β-d-selenomaltoside

Dodecyl-β-d-selenomaltoside in a leukotriene C4 synthase crystal exhibited sufficient anomalous diffraction for multiwavelength anomalous diffraction phasing

CXCL13-producing CD4⁺ T cells accumulate in the early phase of tertiary lymphoid structures in ovarian cancer

卵巣がんにおける新たな免疫の仕組みを発見 --三次リンパ様構造の形成メカニズムと予後への影響を解明--. 京都大学プレスリリース. 2022-08-05.Tertiary lymphoid structures (TLSs) are transient ectopic lymphoid aggregates whose formation might be caused by chronic inflammation states, such as cancer. However, how TLSs are induced in the tumor microenvironment (TME) and how they affect patient survival are not well understood. We investigated TLS distribution in relation to tumor infiltrating lymphocytes (TILs) and related gene expression in high grade serous ovarian cancer (HGSC) specimens. CXCL13 gene expression correlated with TLS presence and the infiltration of T cells and B cells, and was a favorable prognostic factor for HGSC patients. Coexistence of CD8⁺ T cells and B-cell lineages in the TME significantly improved the prognosis of HGSC and was correlated with the presence of TLSs. CXCL13 expression was predominantly coincident with CD4⁺ T cells in TLSs and CD8⁺ T cells in TILs, and shifted from CD4⁺ T cells to CD21⁺ follicular dendritic cells as TLS matured. In a mouse ovarian cancer model, recombinant CXCL13 induced TLSs and enhanced survival by the infiltration of CD8⁺ T cells. These results suggest that TLS formation was associated with CXCL13-producing CD4⁺ T cells and that TLSs facilitated the coordinated antitumor response of cellular and humoral immunity in ovarian cancer

Acquired Evolution of Mitochondrial Metabolism Regulated by HNF1B in Ovarian Clear Cell Carcinoma

Clear cell carcinoma (CCC) of the ovary exhibits a unique morphology and clinically malignant behavior. The eosinophilic cytoplasm includes abundant glycogen. Although the growth is slow, the prognosis is poor owing to resistance to conventional chemotherapies. CCC often arises in endometriotic cysts and is accompanied by endometriosis. Based on these characteristics, three clinical questions are considered: why does ovarian cancer, especially CCC and endometrioid carcinoma, frequently occur in endometriotic cysts, why do distinct histological subtypes (CCC and endometrioid carcinoma) arise in the endometriotic cyst, and why does ovarian CCC possess unique characteristics? Mutations in AT-rich interacting domain-containing protein 1A and phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit alpha genes may contribute to the carcinogenesis of ovarian CCC, whereas hepatocyte nuclear factor-1-beta (HNF1B) plays crucial roles in sculpting the unique characteristics of ovarian CCC through metabolic alterations. HNF1B increases glutathione synthesis, activates anaerobic glycolysis called the Warburg effect, and suppresses mitochondria. These metabolic changes may be induced in stressful environments. Life has evolved to utilize and control energy; eukaryotes require mitochondria to transform oxygen reduction into useful energy. Because mitochondrial function is suppressed in ovarian CCC, these cancer cells probably acquired further metabolic evolution during the carcinogenic process in order to survive stressful environments

The Catalytic Architecture of Leukotriene C4 Synthase with Two Arginine Residues*

Leukotriene (LT) C4 and its metabolites, LTD4 and LTE4, are involved in the pathobiology of bronchial asthma. LTC4 synthase is the nuclear membrane-embedded enzyme responsible for LTC4 biosynthesis, catalyzing the conjugation of two substrates that have considerably different water solubility; that amphipathic LTA4 as a derivative of arachidonic acid and a water-soluble glutathione (GSH). A previous crystal structure revealed important details of GSH binding and implied a GSH activating function for Arg-104. In addition, Arg-31 was also proposed to participate in the catalysis based on the putative LTA4 binding model. In this study enzymatic assay with mutant enzymes demonstrates that Arg-104 is required for the binding and activation of GSH and that Arg-31 is needed for catalysis probably by activating the epoxide group of LTA4