Abstract: TH-PO0653
Thymosin-β4-Mediated Regulation of Macrophage Accumulation and Function in Glomerular Diseases
Session Information
- Glomerular Diseases: Immunopathogenesis and Targeted Therapeutics
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology
Authors
- Man, Cheuk Yan, Royal Veterinary College, London, England, United Kingdom
- Brzoska, Hortensja Lucja, University College London, London, England, United Kingdom
- Robson, Michael G., King's College London, London, England, United Kingdom
- Elliott, Jonathan, Royal Veterinary College, London, England, United Kingdom
- Long, David A., University College London, London, England, United Kingdom
- Vasilopoulou, Elisavet, Royal Veterinary College, London, England, United Kingdom
Background
Thymosin-β4 (Tβ4) has a protective role in the kidney and reduces inflammation and fibrosis in CKD models. Our previous work demonstrated that Tβ4 is expressed in podocytes and macrophages in the murine kidney and that global loss of Tβ4 in the context of glomerular injury leads to exacerbated disease with increased macrophage accumulation. Here we investigate the role of macrophage-produced Tβ4 in disease progression and macrophage function.
Methods
Four groups of bone marrow chimeric mice were generated; WT mice with WT (WT/WT) or KO bone marrow (WT/KO), and KO mice with WT (KO/WT) or KO bone marrow (KO/KO). Glomerulonephritis was induced ten weeks later by administration of nephrotoxic serum (NTS). Macrophage accumulation, albuminuria and blood urea nitrogen (BUN) were assessed 21 days post-NTS. Bone marrow derived macrophages (BMDMs) were isolated from WT and KO mice, polarised to M1 (LPS and IFN-γ) or M2 (IL-4) phenotype and analysed for the expression of pro-inflammatory or pro-fibrotic genes, respectively.
Results
There was increased accumulation of macrophages (CD45+CD11b+F4/80+) in the kidneys of KO/KO compared with WT/WT mice (p = 0.0268), and this was particularly pronounced when assessing bone marrow-derived macrophages (CD45+CD11b+F4/80lo; p = 0.0004). Localisation of F4/80+ macrophages identified increased accumulation surrounding glomeruli in kidneys from KO/KO compared with WT/WT mice (p = 0.007). Albuminuria (p = 0.007) and BUN (p < 0.0001) were significantly higher in KO/KO compared with WT/WT mice. WT/KO and KO/WT groups showed intermediate levels of macrophage accumulation, albuminuria and BUN. In vitro, the expression of Tmsb4x, encoding Tβ4, in BMDMs increased 24h post-stimulation with LPS and IFN-γ. Tnfa expression was reduced in KO compared with WT M1-BMDMs (p = 0.015) at 2h and Arg1 expression was increased in KO compared with WT M2-BMDMs (p = 0.010) at 24h.
Conclusion
Our findings reveal that Tβ4 expression by both bone marrow-derived and kidney-resident cells has a protective role in glomerular disease. We postulate that Tβ4 modulates macrophage function by regulating pro-inflammatory and pro-fibrotic mediators thus modulating renal inflammation and disease progression.