title: Interferon-induced mechanosensing defects impede apoptotic cell clearance in lupus.
abstract: Systemic lupus erythematosus (SLE) is a severe autoimmune disease that is associated with increased circulating apoptotic cell autoantigens (AC-Ags) as well as increased type I IFN signaling. Here, we describe a pathogenic mechanism in which follicular translocation of marginal zone (MZ) B cells in the spleens of BXD2 lupus mice disrupts marginal zone macrophages (MZMs), which normally clear AC debris and prevent follicular entry of AC-Ags. Phagocytosis of ACs by splenic MZMs required the megakaryoblastic leukemia 1 (MKL1) transcriptional coactivator-mediated mechanosensing pathway, which was maintained by MZ B cells through expression of membrane lymphotoxin-α1β2 (mLT). Specifically, type I IFN-induced follicular shuttling of mLT-expressing MZ B cells disengaged interactions between these MZ B cells and LTβ receptor-expressing MZMs, thereby downregulating MKL1 in MZMs. Loss of MKL1 expression in MZMs led to defective F-actin polymerization, inability to clear ACs, and, eventually, MZM dissipation. Aggregation of plasmacytoid DCs in the splenic perifollicular region, follicular translocation of MZ B cells, and loss of MKL1 and MZMs were also observed in an additional murine lupus model and in the spleens of patients with SLE. Collectively, the results suggest that lupus might be interrupted by strategies that maintain or enhance mechanosensing signaling in the MZM barrier to prevent follicular entry of AC-Ags.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Yang-Xin
authors.initials: YX
authors.lastname: Fu
authors.forename: Qi
authors.initials: Q
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.forename: David K
authors.initials: DK
authors.lastname: Crossman
authors.forename: PingAr
authors.initials: P
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Bao
authors.initials: B
authors.lastname: Luo
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Morel
authors.forename: Janusz H
authors.initials: JH
authors.lastname: Kabarowski
authors.forename: Hideo
authors.initials: H
authors.lastname: Yagita
authors.forename: Carl F
authors.initials: CF
authors.lastname: Ware
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Hsu
authors.forename: John D
authors.initials: JD
authors.lastname: Mountz
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology; D003713:Dendritic Cells / Q000276:immunology / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007370:Interferon Type I / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D053259:Lymphotoxin beta Receptor / Q000172:deficiency / Q000235:genetics; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D040542:Mechanotransduction, Cellular / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011971:Receptors, Immunologic / Q000378:metabolism; D026362:Serum Response Factor / Q000172:deficiency / Q000235:genetics; D013154:Spleen / Q000276:immunology / Q000473:pathology; D015534:Trans-Activators / Q000172:deficiency / Q000235:genetics
chemical_list: D001323:Autoantibodies; D007370:Interferon Type I; D053259:Lymphotoxin beta Receptor; C092228:Marco protein, mouse; C511173:Mrtfa protein, mouse; D011971:Receptors, Immunologic; D026362:Serum Response Factor; D015534:Trans-Activators