ILC1 drive intestinal epithelial and matrix remodelling.

Organoids can shed light on the dynamic interplay between complex tissues and rare cell types within a controlled microenvironment. Here, we develop gut organoid cocultures with type-1 innate lymphoid cells (ILC1) to dissect the impact of their accumulation in inflamed intestines. We demonstrate that murine and human ILC1 secrete transforming growth factor ß1, driving expansion of CD44v6+ epithelial crypts. ILC1 additionally express MMP9 and drive gene signatures indicative of extracellular matrix remodelling. We therefore encapsulated human epithelial-mesenchymal intestinal organoids in MMP-sensitive, synthetic hydrogels designed to form efficient networks at low polymer concentrations. Harnessing this defined system, we demonstrate that ILC1 drive matrix softening and stiffening, which we suggest occurs through balanced matrix degradation and deposition. Our platform enabled us to elucidate previously undescribed interactions between ILC1 and their microenvironment, which suggest that they may exacerbate fibrosis and tumour growth when enriched in inflamed patient tissues.

Identification of the YEATS domain of GAS41 as a pH-dependent reader of histone succinylation.

Lysine succinylation is a newly discovered posttranslational modification with distinctive physical properties. However, to date rarely have studies reported effectors capable of interpreting this modification on histones. Following our previous study of SIRT5 as an eraser of succinyl-lysine (Ksuc), here we identified the GAS41 YEATS domain as a reader of Ksuc on histones. Biochemical studies showed that the GAS41 YEATS domain presents significant binding affinity toward H3K122suc upon a protonated histidine residue. Furthermore, cellular studies showed that GAS41 had prominent interaction with H3K122suc on histones and also demonstrated the coenrichment of GAS41 and H3K122suc on the p21 promoter. To investigate the binding mechanism, we solved the crystal structure of the YEATS domain of Yaf9, the GAS41 homolog, in complex with an H3K122suc peptide that demonstrated the presence of a salt bridge formed when a protonated histidine residue (His39) recognizes the carboxyl terminal of the succinyl group. We also solved the apo structure of GAS41 YEATS domain, in which the conserved His43 residue superimposes well with His39 in the Yaf9 structure. Our findings identified a reader of succinyl-lysine, and the binding mechanism will provide insight into the development of specific regulators targeting GAS41.

Personal utility is inherent to direct-to-consumer genomic testing.

People for and against direct-to-consumer (DTC) genomic tests are arguing around two issues: first, on whether an autonomy-based account can justify the tests; second, on whether the tests bring any personal utility. Bunnik et al, in an article published in this journal, were doubtful on the latter, especially in clinically irrelevant and uninterpretable sequences, and how far this claim could go in the justification. Here we argue that personal utility is inherent to DTC genomic tests and their results. We discuss Bunnik et al's account of personal utility and identify problems in its motivation and application. We then explore concepts like utility and entertainment which suggest that DTC genomic tests bring personal utility to their consumers, both in the motivation and the content of the tests. This points to an alternative account of personal utility which entails that entertainment value alone is adequate to justify DTC genomic tests, given appropriate strategies to communicate tests results with the consumers. It supports the autonomy-based justification of the test by showing that DTC genomic test itself stands as a valuable option and facilitates meaningful choice of the people.

Lipid-loaded tumor-associated macrophages sustain tumor growth and invasiveness in prostate cancer.

Tumor-associated macrophages (TAMs) are correlated with the progression of prostatic adenocarcinoma (PCa). The mechanistic basis of this correlation and therapeutic strategies to target TAMs in PCa remain poorly defined. Here, single-cell RNA sequencing was used to profile the transcriptional landscape of TAMs in human PCa, leading to identification of a subset of macrophages characterized by dysregulation in transcriptional pathways associated with lipid metabolism. This subset of TAMs correlates positively with PCa progression and shorter disease-free survival and is characterized by an accumulation of lipids that is dependent on Marco. Mechanistically, cancer cell-derived IL-1ß enhances Marco expression on macrophages, and reciprocally, cancer cell migration is promoted by CCL6 released by lipid-loaded TAMs. Moreover, administration of a high-fat diet to tumor-bearing mice raises the abundance of lipid-loaded TAMs. Finally, targeting lipid accumulation by Marco blockade hinders tumor growth and invasiveness and improves the efficacy of chemotherapy in models of PCa, pointing to combinatorial strategies that may influence patient outcomes.

Deacylation Mechanism by SIRT2 Revealed in the 1'-SH-2'-O-Myristoyl Intermediate Structure.

Sirtuins are NAD-dependent deacylases. Previous studies have established two important enzymatic intermediates in sirtuin-catalyzed deacylation, an alkylamidate intermediate I, which is then converted to a bicyclic intermediate II. However, how intermediate II is converted to products is unknown. Based on potent SIRT2-specific inhibitors we developed, here we report crystal structures of SIRT2 in complexes with a thiomyristoyl lysine peptide-based inhibitor and carba-NAD or NAD. Interestingly, by soaking crystals with NAD, we capture a distinct covalent catalytic intermediate (III) that is different from the previously established intermediates I and II. In this intermediate, the covalent bond between the S and the myristoyl carbonyl carbon is broken, and we believe this intermediate III to be the decomposition product of II en route to form the end products. MALDI-TOF data further support the intermediate III formation. This is the first time such an intermediate has been captured by X-ray crystallography and provides more mechanistic insights into sirtuin-catalyzed reactions.