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Abstract: SA-PO271

A Novel and Unique Fc-Fusion Protein i-Body AD-214 Ameliorates Kidney Fibrosis Through Inhibition of Leukocyte Migration

Session Information

Category: Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

  • 2000 Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)

Authors

  • Cao, Qinghua, Kolling Institute of Medical Research, St Leonards, New South Wales, Australia
  • Chen, Xinming, Kolling Institute of Medical Research, St Leonards, New South Wales, Australia
  • Pollock, Carol A., Kolling Institute of Medical Research, St Leonards, New South Wales, Australia

Group or Team Name

  • Renal Medicine, Kolling Institute.
Background

Tissue fibrosis is the common pathological pathway in progressive chronic kidney disease (CKD). Current clinical practices are ineffective in limiting renal fibrosis. CXCR4 has been demonstrated to be central to the development of fibrosis. The usage of neural cell adhesion molecules as scaffolds by incorporating binding loops, mimicking the shape of shark antibody, allows construction of fully humanized single-domain antibody-like scaffold, designated as i-bodies. The i-body AD-214, which bind CXCR4 with high affinity, has been shown to be effective in limiting lung fibrosis. However, the role of AD-214 in renal fibrosis has not been investigated.

Methods

Renal proximal tubular cells (PTC) were incubated with TGFβ1 with/without AD-214 for 48 hours. Supernatant was collected and collagen-3 (Col-3) and collagen-4 (Col-4) were measured by Western blot. Mice with unilateral ureteral obstruction (UUO) were administrated AD-214 every two days from one day after UUO for 14 days. Changes in renal morphology were examined by H&E and PSR staining. Renal histology, mRNA, analysed by qRT-PCR, extracellular matrix (ECM) and leukocyte markers detected by immunohistochemistry (IHC) and kidney function, assessed by the blood urea nitrogen (BUN) and kidney injury molecule-1 (KIM-1) were examined. The in vitro scratch assay was conducted to investigate the impact of AD-214 on macrophage migration.

Results

AD-214 suppressed TGFβ1-induced overexpression of Col-3 and Col-4 by RPTEC cells compared to negative control. In UUO model, mice treated with AD-214 markedly ameliorated collagen deposition (30.4% reduction) relative to UUO+negative i-body treated group. IHC staining revealed that administration of AD-214 significantly attenuated the Col-4 and fibronectin (FN) deposition by 74.4% and 34.6% respectively relative to negative i-body treatment group. Consistently, physiological parameters BUN and KIM-1 were markedly reduced in mice treated with AD-214. Mechanism studies revealed AD-214 inhibited the infiltration of leukocytes including macrophages and neutrophils into UUO kidneys. In the in vitro scratch assay, AD-214 effectively inhibited the migration of macrophages induced by LPS.

Conclusion

Blocking CXCR4 using the i-body AD-214 is a promising therapeutic strategy to prevent the development of CKD.

Funding

  • Commercial Support – Adalta.Ltd