{
  "id": 5701654,
  "title": "Gpnmb-positive lipid-associated macrophages contribute to lipid clearance during luteolysis",
  "url": "https://urgent.news/2026/09/04/gpnmb-positive-lipid-associated-macrophages-contribute-to-lipid",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-04T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.08.31.748418v1?rss=1"
  },
  "original_language": "en",
  "account": "Macrophages are vital regulators of ovarian function, but their diverse roles remain poorly understood. A recent study has uncovered a specific subset of macrophages, denoted as Gpnmb+, that play a crucial role in lipid clearance during the process of luteolysis, which is the breakdown of the corpus luteum at the end of the menstrual cycle.\n\nBy examining single-cell and spatial transcriptomic datasets from both mouse and human ovaries, researchers identified a dynamic expansion of the Gpnmb+ macrophage population during luteolysis in mice. Similar GPNMB+ macrophage populations were also found in human ovarian single-cell RNA sequencing datasets. Transcriptomic analysis revealed that these Gpnmb+ macrophages share similarities with lipid-associated macrophages (LAMs) found in adipose tissue associated with obesity, displaying strong enrichment in processes such as phagocytosis, lysosomal lipid processing, and reverse cholesterol transport.\n\nUnlike traditional phagocytic macrophages that only clear cellular debris, Gpnmb+ macrophages are specialized in processing lipid-rich targets. They specifically infiltrate regressing corpora lutea (CL), internalizing lipid droplets and interacting with dying luteal cells through several signaling axes, including apoptosis (via Thbs1-Sdc1/4), efferocytosis (via Pros1-Mertk), and cell recruitment (via Cxcl12/Cxcr4). Additionally, Gpnmb+ macrophages surround oocytes in atretic follicles.\n\nThrough a combination of transcriptomic and imaging analyses, the study suggests that Gpnmb+ macrophages orchestrate a comprehensive series of multi-step lipid processing. This includes lipid droplet internalization, lysosomal and lipophagic degradation, and cholesterol efflux mediated by ABCA1/ABCG1. Furthermore, whole-mount imaging revealed a close physical interaction between Gpnmb+ macrophages and LYVE1+ lymphatic endothelial cells, supporting a non-inflammatory resolution for lipid clearance through lymphatic circulation.\n\nIn summary, this research establishes the Gpnmb+ macrophages as specialized lipid-associated macrophages (LAMs) that are essential for maintaining cyclic ovarian lipid homeostasis. This work challenges the traditional notion of LAM biology, demonstrating their vital role in normal ovarian physiology and linking immune-mediated tissue remodeling to reproductive function.",
  "summary": "Macrophages are important regulators of ovarian physiology, yet the complexity in their subpopulations and functions is far from fully understood and is emerging from single-cell analysis of diverse physiological and pathological contexts. One open question in ovarian physiology is how massive lipid loads during structural luteolysis are resolved without inducing inflammation. Here, by…",
  "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."
}