1. HIF1A and NFAT5 coordinate Na+-boosted antibacterial defense via enhanced autophagy and autolysosomal targeting
Patrick Neubert, et al. Autophagy. 2019 Nov;15(11):1899-1916. doi: 10.1080/15548627.2019.1596483. Epub 2019 Apr 14.
Infection and inflammation are able to induce diet-independent Na+-accumulation without commensurate water retention in afflicted tissues, which favors the pro-inflammatory activation of mouse macrophages and augments their antibacterial and antiparasitic activity. While Na+-boosted host defense against the protozoan parasite Leishmania major is mediated by increased expression of the leishmanicidal NOS2 (nitric oxide synthase 2, inducible), the molecular mechanisms underpinning this enhanced antibacterial defense of mouse macrophages with high Na+ (HS) exposure are unknown. Here, we provide evidence that HS-increased antibacterial activity against E. coli was neither dependent on NOS2 nor on the phagocyte oxidase. In contrast, HS-augmented antibacterial defense hinged on HIF1A (hypoxia inducible factor 1, alpha subunit)-dependent increased autophagy, and NFAT5 (nuclear factor of activated T cells 5)-dependent targeting of intracellular E. coli to acidic autolysosomal compartments. Overall, these findings suggest that the autolysosomal compartment is a novel target of Na+-modulated cell autonomous innate immunity.
2. N,N'-Dicarb-oxy-N,N'-dicarboxyl-ato(m-phenyl-ene)dimethanaminium monohydrate
Yu-Xing Qiang, Shou-Rong Zhu, Min Shao Acta Crystallogr Sect E Struct Rep Online. 2011 May 1;67(Pt 5):o1174. doi: 10.1107/S1600536811013675. Epub 2011 Apr 22.
In the title inner salt, C(16)H(20)N(2)O(8)·H(2)O, two of four carboxyl groups are deprotonated, while the two imine groups are protonated. The two imino-diacetate groups are located on the same side of the benzene ring plane. Extensive inter-molecular O-H⋯O and N-H⋯O hydrogen bonds occur in the crystal.
3. PI3KC3 complex subunit NRBF2 is required for apoptotic cell clearance to restrict intestinal inflammation
Ming-Yue Wu, et al. Autophagy. 2021 May;17(5):1096-1111. doi: 10.1080/15548627.2020.1741332. Epub 2020 Mar 19.
NRBF2, a regulatory subunit of the ATG14-BECN1/Beclin 1-PIK3C3/VPS34 complex, positively regulates macroautophagy/autophagy. In this study, we report that NRBF2 is required for the clearance of apoptotic cells and alleviation of inflammation during colitis in mice. NRBF2-deficient mice displayed much more severe colitis symptoms after the administration of ulcerative colitis inducer, dextran sulfate sodium salt (DSS), accompanied by prominent intestinal inflammation and apoptotic cell accumulation. Interestingly, we found that nrbf2-/- mice and macrophages displayed impaired apoptotic cell clearance capability, while adoptive transfer of nrbf2+/+ macrophages to nrbf2-/- mice alleviated DSS-induced colitis lesions. Mechanistically, NRBF2 is required for the generation of the active form of RAB7 to promote the fusion between phagosomes containing engulfed apoptotic cells and lysosomes via interacting with the MON1-CCZ1 complex and regulating the guanine nucleotide exchange factor (GEF) activity of the complex.