bims-adipim 2023-08-20 papers

Issue of 2023–08–20
two papers selected by
Matthew C. Sinton, University of Glasgow

Nat Commun. 2023 Aug 17. 14(1): 4972

RORγt-Raftlin1 complex regulates the pathogenicity of Th17 cells and colonic inflammation.

Amir Kumar Singh, Ritesh Kumar, Jianyi Yin, John F Brooks Ii, Mahesh Kathania, Sandip Mukherjee, Jitendra Kumar, Kevin P Conlon, Venkatesha Basrur, Zhe Chen, Xianlin Han, Lora V Hooper, Ezra Burstein, K Venuprasad.

Th17 cells that produce Interleukin IL-17 are pathogenic in many human diseases, including inflammatory bowel disease, but are, paradoxically, essential for maintaining the integrity of the intestinal barrier in a non-inflammatory state. However, the intracellular mechanisms that regulate distinct transcriptional profiles and functional diversity of Th17 cells remain unclear. Here we show Raftlin1, a lipid raft protein, specifically upregulates and forms a complex with RORγt in pathogenic Th17 cells. Disruption of the RORγt-Raftlin1 complex results in the reduction of pathogenic Th17 cells in response to Citrobacter rodentium; however, there is no effect on nonpathogenic Th17 cells in response to commensal segmented filamentous bacteria. Mechanistically, we show that Raftlin1 recruits distinct phospholipids to RORγt and promotes the pathogenicity of Th17 cells. Thus, we have identified a mechanism that drives the pathogenic function of Th17 cells, which could provide a platform for advanced therapeutic strategies to dampen Th17-mediated inflammatory diseases.

DOI: https://doi.org/10.1038/s41467-023-40622-1

Sci Rep. 2023 08 14. 13(1): 13227

The metabolic effects of resumption of a high fat diet after weight loss are sex dependent in mice.

Santiago Guerra-Cantera, Laura M Frago, María Jiménez-Hernaiz, Roberto Collado-Pérez, Sandra Canelles, Purificación Ros, Jorge García-Piqueras, Iris Pérez-Nadador, Vicente Barrios, Jesús Argente, Julie A Chowen.

Dietary restriction is a frequent strategy for weight loss, but adherence is difficult and returning to poor dietary habits can result in more weight gain than that previously lost. How weight loss due to unrestricted intake of a healthy diet affects the response to resumption of poor dietary habits is less studied. Moreover, whether this response differs between the sexes and if the insulin-like growth factor (IGF) system, sex dependent and involved in metabolic control, participates is unknown. Mice received rodent chow (6% Kcal from fat) or a high-fat diet (HFD, 62% Kcal from fat) for 4 months, chow for 3 months plus 1 month of HFD, or HFD for 2 months, chow for 1 month then HFD for 1 month. Males and females gained weight on HFD and lost weight when returned to chow at different rates (p < 0.001), but weight gain after resumption of HFD intake was not affected by previous weight loss in either sex. Glucose metabolism was more affected by HFD, as well as the re-exposure to HFD after weight loss, in males. This was associated with increases in hypothalamic mRNA levels of IGF2 (p < 0.01) and IGF binding protein (IGFBP) 2 (p < 0.05), factors involved in glucose metabolism, again only in males. Likewise, IGF2 increased IGFBP2 mRNA levels only in hypothalamic astrocytes from males (p < 0.05). In conclusion, the metabolic responses to dietary changes were less severe and more delayed in females and the IGF system might be involved in some of the sex specific observations.

DOI: https://doi.org/10.1038/s41598-023-40514-w