Targeting Anti-TGF-β Therapy to Fibrotic Kidneys with a Dual Specificity Antibody Approach

Area of Science:

• Renal pathology and therapeutic targeting
• Molecular engineering and drug delivery
• Extracellular matrix protein interactions

Background:

• Targeted drug delivery to diseased kidneys remains a significant challenge.
• Fibronectin extra domain A (FnEDA) is upregulated at sites of tissue injury.
• Transforming growth factor-beta (TGF-β) plays a critical role in renal fibrosis.

Purpose of the Study:

• To design and evaluate a bispecific antibody for targeted delivery to FnEDA in fibrotic kidneys.
• To assess the therapeutic efficacy of neutralizing TGF-β using this targeted approach.
• To compare the kidney-specific accumulation of the bispecific antibody versus a standard TGF-β antibody.

Main Methods:

• Construction of a bispecific dual variable domain Ig (DVD-Ig) molecule targeting FnEDA and TGF-β.
• Utilized a mouse unilateral ureteral obstruction (UUO) model to induce renal fibrosis.
• Employed whole-body single-photon emission computed tomography (SPECT) for imaging molecule distribution.
• Assessed collagen deposition and gene expression (Col1a1, FnEDA, TIMP1) via immunohistochemistry and mRNA analysis.

Main Results:

• The bispecific TGF-β + FnEDA DVD-Ig showed significantly higher accumulation in the obstructed fibrotic kidney compared to other tissues.
• Systemic administration of the bispecific DVD-Ig attenuated collagen deposition and reduced fibrotic gene expression in the injured kidney.
• A non-targeted TGF-β antibody exhibited lower kidney accumulation and a more diffuse distribution.

Conclusions:

• A bispecific molecule targeting FnEDA enables targeted delivery of therapeutic TGF-β neutralization to fibrotic kidneys.
• This strategy results in focal uptake in the diseased kidney, offering a promising approach to reduce renal fibrosis.
• Targeting extracellular matrix proteins represents a viable strategy for enhancing drug delivery in kidney disease.