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24 Publications visible to you, out of a total of 24
Hydropersulfides inhibit lipid peroxidation and ferroptosis by scavenging radicals

Abstract (Expand)

erroptosis is a type of cell death caused by radical-driven lipid peroxidation, leading to membrane damage and rupture. Here we show that enzymatically produced sulfane sulfur (S0) species, specifically … hydropersulfides, scavenge endogenously generated free radicals and, thereby, suppress lipid peroxidation and ferroptosis. By providing sulfur for S0 biosynthesis, cysteine can support ferroptosis resistance independently of the canonical GPX4 pathway. Our results further suggest that hydropersulfides terminate radical chain reactions through the formation and self-recombination of perthiyl radicals. The autocatalytic regeneration of hydropersulfides may explain why low micromolar concentrations of persulfides suffice to produce potent cytoprotective effects on a background of millimolar concentrations of glutathione. We propose that increased S0 biosynthesis is an adaptive cellular response to radical-driven lipid peroxidation, potentially representing a primordial radical protection system.

Authors: Uladzimir Barayeu, Danny Schilling, Mohammad Eid, Thamara Nishida Xavier da Silva, Lisa Schlicker, Nikolina Mitreska, Christopher Zapp, Frauke Gräter, Aubry K. Miller, Reinhard Kappl, Almut Schulze, José Pedro Friedmann Angeli, Tobias P. Dick

Date Published: 15th Sep 2022

Publication Type: Journal

A Conformational Transition of the D’D3 Domain primes von Willebrand Factor for Multimerization

Abstract (Expand)

Von Willebrand factor (VWF) is a multimeric plasma glycoprotein that is critically involved in hemostasis. Biosynthesis of long VWF concatemers in the endoplasmic reticulum and the (trans-)Golgi is … still not fully understood. We use the single-molecule force spectroscopy technique magnetic tweezers to analyze a previously hypothesized conformational change in the D’D3 domain crucial for VWF multimerization. We find that the interface formed by submodules C8-3, TIL3, and E3 wrapping around VWD3 can open and expose two buried cysteines, Cys1099 and Cys1142, that are vital for multimerization. By characterizing the conformational change at varying levels of force, we are able to quantify the kinetics of the transition and the stability of the interface. We find a pronounced destabilization of the interface upon lowering the pH from 7.4 to 6.2 and 5.5. This is consistent with initiation of the conformational change that enables VWF multimerization at the D’D3 domain by a decrease in pH in the trans-Golgi network and Weibel-Palade bodies. Furthermore, we find a stabilization of the interface in the presence of coagulation factor VIII (FVIII), providing evidence for a previously hypothesized binding site in submodule C8-3. Our findings highlight the critical role of the D’D3 domain in VWF biosynthesis and function and we anticipate our methodology to be applicable to study other, similar conformational changes in VWF and beyond.

Authors: Sophia Gruber, Achim Löf, Adina Hausch, Fabian Kutzki, Res Jöhr, Tobias Obser, Gesa König, Reinhard Schneppenheim, Camilo Aponte-Santamaría, Frauke Gräter, Maria A. Brehm, Martin Benoit, Jan Lipfert

Date Published: 2nd Jun 2022

Publication Type: Journal

Mechano-redox control of Mac-1 de-adhesion from ICAM-1 by protein disulfide isomerase promotes directional movement of neutrophils under flow

Abstract (Expand)

Macrophage-1 antigen or Mac-1 (CD11b/CD18, αMβ2) is a leukocyte integrin essential for firm adhesion of neutrophils, lymphocytes and monocytes against flow when recruited to the endothelium. To migrate … to the site of inflammation, leukocytes require coordinated adhesion and de-adhesion for directional movement. The vascular thiol isomerase, protein disulfide isomerase (PDI), was found by fluorescence microscopy to colocalize with high affinity Mac-1 at the trailing edge of stimulated neutrophils when adhered to ICAM-1 under fluid shear. From differential cysteine alkylation and mass spectrometry studies, PDI cleaves two allosteric disulfide bonds, C169-C176 and C224-C264, in the βI domain of the β2 subunit, and in mutagenesis and cell transfection studies, cleavage of the C224-C264 disulfide bond was shown to selectively control Mac-1 dis-engagement from ICAM-1 under fluid shear. Molecular dynamics simulations and binding of conformation-specific antibodies reveal that cleavage of the C224-C264 bond induces conformational change and mechanical stress in the βI domain that allosterically alters exposure of an αI domain epitope and shifts Mac-1 to a lower affinity state. From studies of neutrophil adherence to ICAM-1 under fluid shear, these molecular events promote neutrophil motility in the direction of flow at high shear stress. In summary, shear-dependent PDI cleavage of neutrophil Mac-1 C224-C264 disulfide bond triggers Mac-1 de-adherence from ICAM-1 at the trailing edge of the cell and enables directional movement of neutrophils during inflammation.

Authors: Alexander Dupuy, Camilo Aponte-Santamaría, Adva Yeheskel, Frauke Gräter, Philip J. Hogg, Freda H. Passam, Joyce Chiu

Date Published: 30th Mar 2022

Publication Type: Journal

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