Tissue-targeted R-spondin mimetics for liver regeneration

Area of Science:

• Biochemistry
• Molecular Biology
• Regenerative Medicine

Background:

• R-spondin (RSPO) proteins are key Wnt signaling pathway modulators.
• RSPO proteins stimulate tissue regeneration, but lack tissue specificity.
• Targeted RSPO mimetics are needed for precise regenerative therapies.

Purpose of the Study:

• To engineer a tissue-specific RSPO mimetic molecule.
• To target RSPO activity to liver cells using the ASGR1 receptor.
• To evaluate the efficacy of the targeted RSPO mimetic in liver regeneration.

Main Methods:

• Mutated RSPO2 (RSPO2 F105R/F109A) to abolish LGR binding while retaining ZNRF3/RNF43 binding.
• Created a bi-specific molecule (αASGR1-RSPO2-RA) by linking mutated RSPO2 to an ASGR1-targeting antibody.
• Assessed in vitro Wnt signaling enhancement and in vivo effects in healthy and diseased mice.

Main Results:

• The αASGR1-RSPO2-RA molecule enhanced Wnt signaling specifically in ASGR1-expressing cells in vitro.
• Systemic administration upregulated Wnt target genes and stimulated liver cell proliferation in mice.
• Improved liver function in diseased mice, with no observed effects in the intestine.
• Demonstrated tissue-specific regenerative potential of the engineered molecule.

Conclusions:

• Engineered RSPO mimetic proteins can achieve tissue-specific Wnt pathway modulation.
• This approach provides a blueprint for developing targeted regenerative therapies.
• Targeted RSPO mimetics offer a promising strategy for treating liver diseases and promoting regeneration.