Nuclear lamin B is crucial to the nuclear envelope integrity and extracellular trap release in neutrophils

Abstract

Its not clear how nuclear envelope (NE) is ruptured for chromatin externalization during NETosis. The membrane rupture during neutrophil NET release was described as a membrane lysis process, this notion, however, has been questioned. Here, we found that lamin B, the structural NE component, was involved in NETosis. Unexpectedly, lamin B was not fragmented by destructive proteolysis, but rather disassembled into its intact full-length molecule, in NETotic cells with ruptured NE. In the mechanistic study, our experiments demonstrated that cytosolic PKC translocated to the nucleus, where it serves as a NETotic lamin kinase to induce lamin B phosphorylation, following by lamina disassembly and NE rupture. To determine causality, we found that decreasing lamin B phosphorylation, by PKC inhibition or genetic deletion, or mutation at the PKC consensus phosphorylation sites of lamin B, attenuated extracellular trap formation. Importantly, strengthening NE by lamin B overexpression attenuated neutrophil NETosis in vivo and alleviated exhibition of NET-associated inflammatory cytokines in UVB irradiated skin of lamin B transgenic mice. These findings advance our understanding of NETosis process and elucidate a cellular mechanism that PKC-mediated lamin B phosphorylation drives nuclear envelope rupture for NET release in neutrophils.\n\nGraphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC=\"FIGDIR/small/647529v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (49K):\norg.highwire.dtl.DTLVardef@7bd231org.highwire.dtl.DTLVardef@124bf6dorg.highwire.dtl.DTLVardef@19396ecorg.highwire.dtl.DTLVardef@9989cb_HPS_FORMAT_FIGEXP M_FIG C_FIG