{
  "id": 3407481,
  "title": "Syndecan-4 exerts canonical heparan sulfate-dependent and noncanonical heparan sulfate-independent functions that regulate Aβ amyloid homeostasis",
  "url": "https://urgent.news/2026/08/25/syndecan-4-exerts-canonical-heparan-sulfate-dependent-and",
  "topic": "science",
  "section": "Science",
  "published": "2026-08-25T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.21.743990v1?rss=1"
  },
  "original_language": "en",
  "account": "Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPGs) are crucial components of amyloid deposits in Alzheimer's disease (AD) and other amyloidoses. Traditionally, these molecules have been thought to facilitate amyloid deposition by accelerating protein aggregation and impeding clearance in a HS-dependent manner. However, recent research on Syndecan-4 (Sdc4) has revealed a more complex role in Aβ amyloid homeostasis.\n\nUsing advanced proteomic techniques, researchers focused on Sdc4, the most increased transmembrane HSPG observed in AD brain tissue and in mice developing Aβ amyloid deposits. Through spatial association analysis using proximity ligation assays (PLA), scientists confirmed the spatial connection between Sdc4 and Aβ amyloid deposits. In vitro experiments demonstrated that Sdc4 ectodomain accelerated Aβ fibril formation in a HS-dependent manner.\n\nInterestingly, however, overexpressing Sdc4 in CHO cells, hiPSC-derived neurons, and organotypic brain slice cultures (OBSCs) unexpectedly reduced Aβ production. This reduction was accompanied by dramatic decreases in sAPP and C83 levels, as well as increased immature APP levels in the cells. Sdc4 promoted altered APP localization into detergent-resistant membrane domains and increased APP association with ATG5+/LC3+/Cathepsin D+ vesicles.\n\nFurther investigation revealed that the transmembrane region of Sdc4 mediates these effects in a glycosaminoglycan-independent manner. Intriguingly, Sdc4 overexpression in the brains of APP mice significantly reduced amyloid deposition at an early age, challenging the prevailing notion that increased HSPG levels in AD always promote amyloidogenesis.\n\nIn conclusion, Sdc4 exhibits paradoxical and mechanistically distinct effects that could impact AD pathogenesis differently. These findings suggest that Sdc4 may play a previously unrecognized role in regulating amyloid homeostasis in AD, potentially both promoting and suppressing Aβ fibrillation and production.",
  "summary": "Background Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPGs) are components of the amyloid deposits in Alzheimers disease (AD) and other amyloidoses. HS and HSPGs are canonically thought to facilitate amyloid deposition by accelerating the aggregation of amyloidogenic proteins and impairing their clearance in a HS-dependent manner. Methods Leveraging insights from large-scale…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}