Osr1 Interacts Synergistically with Wt1 to Regulate Kidney Organogenesis

Area of Science:

• Developmental Biology
• Genetics
• Nephrology

Background:

• Renal hypoplasia is a significant cause of pediatric renal failure and adult-onset kidney diseases.
• A variant in the OSR1 gene has been linked to reduced kidney size and function in heterozygotes and kidney defects in homozygotes.
• The precise role of OSR1 in kidney development and nephron endowment remains unclear.

Purpose of the Study:

• To investigate the role of OSR1 in kidney development.
• To explore the interaction between OSR1 and WT1 during kidney organogenesis.
• To understand how OSR1 and WT1 synergistically regulate nephron endowment.

Main Methods:

• Utilized CRISPR genome editing technology to genetically label the Osr1 protein in mice.
• Generated and analyzed mice with single and compound heterozygous null alleles for Osr1 and Wt1.
• Examined kidney development at embryonic stages (E10.5 and E11.5) using histological analysis and gene expression profiling.

Main Results:

• Osr1 interacts with Wt1 in the developing kidney.
• Mice heterozygous for both Osr1 and Wt1 (Osr1+/-Wt1+/-) exhibit significant defects in metanephric kidney development, including agenesis or hypoplasia.
• These defects are associated with reduced nephron progenitor cells (Pax2-positive and Six2-positive) and decreased expression of Gdnf, a key nephrogenic signal.
• Kidney morphogenesis and branching are impaired in Osr1+/-Wt1+/- embryos.

Conclusions:

• Osr1 and Wt1 act synergistically to regulate nephron endowment.
• This synergy is achieved by controlling the specification of metanephric mesenchyme during early nephrogenesis.
• Understanding this interaction is crucial for addressing kidney development disorders.