{
  "abstract": "Microglial activation in response to lipopolysaccharide (LPS) requires Toll-like receptor 4 (TLR4) redistribution into cholesterol- and sphingolipid-rich membrane domains, yet the lipid determinants of this process remain unclear. Here, we identify cholesterol accessibility as a key driver of TLR4-dependent microglial activation. We show that LPS increases cholesterol uptake and mobilization, whereas inhibition of intracellular cholesterol trafficking or the plasma membrane-to-ER cholesterol transporter Aster attenuates inflammatory responses. Scavenger receptor class B type 1 (SR-B1) mediates LPS-induced cholesterol uptake, and its inhibition suppresses TLR4 signaling, receptor recruitment to detergent-resistant membrane domains, and TLR4 endocytosis without altering bulk cellular cholesterol. Instead, SR-B1 inhibition remodels the sphingolipidome and expands the sphingomyelin-associated cholesterol pool, as detected by OlyA, while LPS promotes remodeling of this pool and increases accessible cholesterol detected by D4H. Manipulation of sphingomyelin-cholesterol interactions alters membrane properties and TLR4 trafficking, while stabilization of these complexes suppresses inflammatory activation. In vivo, LPS induces remodeling of sphingomyelin-associated cholesterol in microglia, whereas Alzheimer's disease-related ApoE4/Trem2R47H microglia show impaired cholesterol-pool remodeling and enhanced inflammatory responses. Together, these findings establish sphingolipid-dependent cholesterol accessibility as a key regulatory layer controlling TLR4 organization and microglial inflammatory activation, positioning SR-B1 as an upstream regulator of this lipid-signaling axis.",
  "abstract_shown": true,
  "affiliations": [
    "Centro de investigaciones Biológicas-Margarita Salas (CSIC)"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "name": "C. Anton-Barros"
    },
    {
      "name": "B. Villarejo-Zori"
    },
    {
      "name": "S. Carmona-Lorenzo"
    },
    {
      "name": "J. M. Barbero-Paredes"
    },
    {
      "name": "D. Gonzalez-Diaz"
    },
    {
      "name": "M. Uceda"
    },
    {
      "name": "A. Fernandez-Bernal"
    },
    {
      "name": "M. Portero-Otin"
    },
    {
      "name": "I. Ayuso-Fernandez"
    },
    {
      "name": "C. Galiana-Rosello"
    },
    {
      "name": "F. Garcia-Garcia"
    },
    {
      "name": "E. Navarro"
    },
    {
      "affs": [
        0
      ],
      "name": "J. Montesinos"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fd0hkg5cscrz0.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.10.750647",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.10.750647v1.full",
  "id": "fd0hkg5cscrz0",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.10.750647v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "molecular biology"
    ],
    [
      "openalex",
      "2808|Neuroinflammation and Neurodegeneration Mechanisms"
    ]
  ],
  "openalex": "W7213210192",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.10.750647v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-10",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fd0hkg5cscrz0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:05Z",
      "native_id": "10.64898/2026.09.10.750647",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.10.750647v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "biorxiv:molecular biology",
      "subfield": "molecular-biology"
    }
  ],
  "title": "A sphingomyelin-cholesterol complex regulates TLR4 activation in microglia",
  "title_text": "A sphingomyelin-cholesterol complex regulates TLR4 activation in microglia",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:05Z",
  "url": "https://research.draconitic.com/paper/fd0hkg5cscrz0",
  "venue": "bioRxiv",
  "versions": []
}