Developing next-generation RNA inhibitors for stroke therapy

Summary: MicroRNAs (miRNAs or miRs) are short, non-coding RNAs emerging as promising tools for treating various diseases, including cancer and stroke. Their small size and similar sequences across species make them ideal targets for drug development. Recent FDA approvals for mRNA-targeting drugs, like Mipomersen for hypolipidemia and Nusinersen for spinal muscular atrophy, highlight progress in this field. However, miRNA- targeted therapies, especially for conditions like ischemic stroke, require more research. This proposal focuses on the miR-200/141 family, particularly miR-141-3p, which is significantly upregulated in stroke cases. Our recent studies show that stroke and factors altering stroke responses, such as social isolation, can modulate miRNAs from the miR-200/141 family. Specifically, miR-141-3p expression is highly upregulated. Treatments with commercial phosphorothioate (PS) or Peptide Nucleic Acid (PNA)-based miR-141-3p inhibitors have significantly reduced stroke injury, proving effective in both young and aged animals. Our preliminary data suggest that move advanced serine gamma PNA-based miR-141-3p inhibitors (sγPNA-141) are highly efficacious (>60% vs. PNA) in inhibiting miR-141-3p expression, reducing infarct injury, and improving long-term functional recovery after ischemic stroke. Elevated levels of miR-141-3p in human stroke patients make it a promising target for stroke therapy. Peptide nucleic acids (PNAs) are synthetic DNA mimics that bind to miRNA target sites, inhibiting their function. This proposal aims to develop new PNA analogs, such as gamma (γ)PNAs and several other analogues, with improved binding and solubility, thereby enhancing their effectiveness as miRNA inhibitors. The primary goal is to establish γPNAs-141 as effective treatments for ischemic stroke. The research includes three aims: 1. Synthesize and characterize newer and more potent γPNA-based miR-141-3p inhibitors (γPNA-141), using advanced γPNA-141 for better efficacy. We will perform quality control and assess binding affinity. 2.Identify the most effective γPNA-141 inhibitors and study their neuroprotective mechanisms in stroke models.3. Determine the optimal treatment window and assess the long-term recovery effects in aged mice after stroke.