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Scientific reports2026; 16(1); 12045; doi: 10.1038/s41598-026-46595-7

Milk fat globule EGF and factor V/VIII domain containing (MFGE8) as a novel player in equine endometrial fibrosis.

Abstract: With increasing age, mares are frequently affected by endometrial fibrosis. Transforming growth factor beta 1 (TGF-β1) promotes fibrosis, while milk fat globule EGF and factor V/VIII domain containing (MFGE8) primarily exerts antifibrotic effects. We used in situ hybridization analysis (ISH) to investigate MFGE8, TGFB1 and its downstream effectors cellular communication network factor 2 (CCN2) and transgelin (TAGLN) in equine endometrial fibrosis. Additionally, transcriptional effects of TGF-β1 and MFGE8 on equine endometrial fibroblasts in vitro were investigated by single cell sequencing. Fibrotic areas overexpressing TGFB1 displayed increased CCN2 and TAGLN expression. The vast majority of glandular areas overexpressing MFGE8 were affected by fibrosis, confirming its relevance in equine endometrial fibrosis. Single cell sequencing following TGF-β1 exposure of fibroblasts confirmed its profibrotic effects. MFGE8 treatment effects were subtler, including decreased profibrotic leukemia inhibitory factor expression and an upregulation of interferon alpha and beta signaling in a subset of cells. In a fibroblast subpopulation, upregulation of phosphatase and tensin homolog signaling, indicated an antifibrotic effect of MFGE8. In conclusion, our study reaffirms the profibrotic effects of TGF-β1 and highlights MFGE8 as a novel player in equine endometrial fibrosis with our results suggesting an antifibrotic effect of MFGE8.
Publication Date: 2026-04-09 PubMed ID: 41957463PubMed Central: PMC13069092DOI: 10.1038/s41598-026-46595-7Google Scholar: Lookup
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  • Journal Article

Summary

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Overview

  • This study investigates the roles of two molecules, TGF-β1 and MFGE8, in the development of endometrial fibrosis in horses, highlighting MFGE8 as a newly identified factor with potential antifibrotic effects.

Background

  • Endometrial fibrosis is a common condition in aging mares, characterized by the excessive formation of fibrous tissue in the uterine lining, impairing reproductive function.
  • TGF-β1 (Transforming Growth Factor Beta 1) is a well-known molecule that promotes fibrosis by stimulating fibroblasts and extracellular matrix production.
  • MFGE8 (Milk fat globule EGF and factor V/VIII domain containing) is recognized mainly for its antifibrotic properties but has not been extensively studied in equine endometrial fibrosis prior to this research.

Objectives

  • To examine the expression of MFGE8, TGF-β1, and downstream fibrotic markers (CCN2 and TAGLN) in fibrotic regions of equine endometrial tissue using in situ hybridization (ISH).
  • To investigate the direct molecular effects of TGF-β1 and MFGE8 on equine endometrial fibroblasts in vitro using single-cell RNA sequencing.

Methods

  • In Situ Hybridization (ISH): Used to localize gene expression of MFGE8, TGFB1, CCN2, and TAGLN in equine endometrial tissue sections, distinguishing fibrotic from non-fibrotic areas.
  • Single-cell RNA Sequencing (scRNA-seq): Examined transcriptomic changes in equine endometrial fibroblasts after treatment with TGF-β1 or MFGE8 to identify downstream effects at the cellular level.

Key Findings

  • Fibrotic tissue analysis: Fibrotic areas showed high expression of TGFB1 along with its downstream fibrotic effectors CCN2 and TAGLN, confirming their role in fibrosis promotion.
  • MFGE8 expression: MFGE8 was predominantly found in glandular regions of endometrial tissue that were fibrotic, indicating its significant involvement in the fibrotic process.
  • TGF-β1 effects on fibroblasts: Confirmed strong profibrotic activity by upregulating fibrotic genes, reinforcing its central role in promoting fibrosis in equine endometrium.
  • MFGE8 effects on fibroblasts:
    • Induced subtle changes indicating potential antifibrotic roles.
    • Decreased expression of leukemia inhibitory factor (a profibrotic marker).
    • Increased interferon alpha and beta signaling in certain fibroblast subsets, which can have antifibrotic and anti-inflammatory effects.
    • Activation of phosphatase and tensin homolog (PTEN) signaling pathways, further supporting an antifibrotic influence in a subset of cells.

Conclusions

  • The study reconfirms that TGF-β1 is a key profibrotic driver in equine endometrial fibrosis.
  • MFGE8 emerges as a novel factor involved in this fibrotic process, with evidence supporting its role in counteracting fibrosis.
  • These findings suggest that MFGE8 might serve as a therapeutic target or biomarker for managing or preventing endometrial fibrosis in mares.

Significance and Future Directions

  • Understanding the dual roles of profibrotic (TGF-β1) and antifibrotic (MFGE8) factors offers new insights into the complex regulation of equine endometrial fibrosis.
  • Future research could focus on elucidating the precise mechanisms by which MFGE8 modulates fibrosis and testing its therapeutic potential in vivo.
  • This knowledge could potentially improve reproductive health and longevity in mares affected by age-related endometrial fibrosis.

Cite This Article

APA
Zu Klampen E, Neufeld G, Klein C. (2026). Milk fat globule EGF and factor V/VIII domain containing (MFGE8) as a novel player in equine endometrial fibrosis. Sci Rep, 16(1), 12045. https://doi.org/10.1038/s41598-026-46595-7

Publication

ISSN: 2045-2322
NlmUniqueID: 101563288
Country: England
Language: English
Volume: 16
Issue: 1
PII: 12045

Researcher Affiliations

Zu Klampen, Elena
  • Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt Am Rübenberge, Germany.
Neufeld, Gregor
  • Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt Am Rübenberge, Germany.
Klein, Claudia
  • Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt Am Rübenberge, Germany. claudia.klein@fli.de.

MeSH Terms

  • Animals
  • Horses
  • Female
  • Fibrosis
  • Endometrium / pathology
  • Endometrium / metabolism
  • Transforming Growth Factor beta1 / metabolism
  • Transforming Growth Factor beta1 / genetics
  • Milk Proteins / metabolism
  • Milk Proteins / genetics
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Horse Diseases / metabolism
  • Horse Diseases / pathology
  • Horse Diseases / genetics
  • Signal Transduction

Conflict of Interest Statement

Declarations. Competing interests: The authors declare no competing interests.

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