Lipid nanoparticles decorated with the brain-targeting peptide RVG29 and mannose successfully delivered siRNA across the blood-brain barrier to silence a damaging gene in brain cells, reducing brain injury in newborn mice.
p<0.0001 for astrocyte activation reductionRVG29 peptide-functionalized nanoparticles delivered siRNA across the blood-brain barrier, silencing circHIPK2 and significantly reducing neuroinflammation in neonatal mice with brain injury
What the researchers found
Dual-modified lipid nanoparticles functionalized with RVG29 peptide (for BBB penetration) and mannose (for astrocyte targeting) delivered circHIPK2 siRNA to the brain with high specificity. The 134 nm nanoparticles showed good stability and biosafety. CircHIPK2 silencing markedly suppressed astrocyte activation, reducing GFAP and IL-1β expression (p<0.0001 in vivo). Neurobehavioral testing showed significantly improved righting reflex, negative geotaxis, and spatial learning/memory in treated neonatal mice with hypoxic-ischemic brain damage.
Why it matters
Neonatal HIE affects 1–6 per 1,000 live births and can cause lifelong disability including cerebral palsy and cognitive impairment. The only current treatment is therapeutic hypothermia (cooling), which has limited efficacy. This study demonstrates a proof-of-concept for peptide-guided nanoparticle delivery of gene therapy directly to the brain cells responsible for neuroinflammation, offering a fundamentally new approach to treating newborn brain injury.
The numbers in context
134 nm nanoparticle size · RVG29 peptide for brain targeting · Mannose for astrocyte targeting · Significant GFAP and IL-1β reduction (p<0.0001) · Improved neurobehavioral recovery
How the study worked
Lipid nanoparticles were constructed with DSPE-PEG2000-RVG29 peptide and mannose surface modifications and loaded with circHIPK2 siRNA. Physicochemical properties, stability, and biocompatibility were characterized. Efficacy was tested in an in vitro oxygen-glucose deprivation model and in vivo in neonatal C57BL/6 mice with hypoxic-ischemic brain damage. Astrocyte activation markers (GFAP, IL-1β) were measured by western blot, qRT-PCR, and immunofluorescence. Neurobehavioral recovery was assessed by righting reflex, negative geotaxis, and Morris water maze tests.
Who was studied
In vitro oxygen-glucose deprivation model and neonatal mouse model of hypoxic-ischemic brain damage
What this study cannot tell us
This is a preclinical mouse study — neonatal mice have a simpler brain structure and different BBB properties than human newborns. The long-term effects and safety of circHIPK2 silencing are unknown. Manufacturing scalability and regulatory pathway for this complex nanoparticle system are significant translational challenges. The specific timing window for treatment after birth injury was not extensively explored.
How to read the evidence
This is a preclinical proof-of-concept study combining in vitro and in vivo models. While the nanoparticle system shows excellent targeting and therapeutic efficacy in mice, the complexity of the formulation and the distance from human clinical application make this very early-stage research.
When this study was published
Published in 2025, this represents cutting-edge work at the intersection of peptide-based drug delivery, RNA therapeutics, and neonatal neurology.
The bigger picture
Brain-targeted drug delivery is one of the biggest challenges in neuroscience — the blood-brain barrier blocks most drugs from reaching the brain. The RVG29 peptide (derived from the rabies virus, which has evolved to efficiently enter the nervous system) has emerged as one of the most promising brain-targeting ligands. This study demonstrates its use in a clinically urgent context — neonatal brain injury — and showcases the potential of combining peptide-based targeting with RNA interference therapy for neurological diseases.
Questions still open
- What is the therapeutic time window after birth injury for this nanoparticle treatment to be effective?
- Could this RVG29/mannose dual-targeting platform deliver other therapeutic molecules for different neurological conditions?
- Would the RVG29 peptide targeting system work in larger animal models with more human-like blood-brain barrier properties?
Common questions
What is RVG29 and how does it help drugs reach the brain?
What is hypoxic-ischemic encephalopathy and why do we need new treatments?
Read the original research
Dual-Modified Mannose/RVG29 Peptide-Functionalized Lipid Nanoparticles Loaded With circHIPK2 siRNA Ameliorate Hypoxic-Ischemic Brain Damage in Neonatal Mice by Suppressing Astrocyte Activation.
Journal of integrative neuroscience, 24(12), 45212
Citation
Dang, Yinxia; Shen, Fuhui; Wang, Shengxia; Zhang, Yating; Lu, Xia; Qin, Dongyuan; Feng, Dan; Song, Yanjun; Cheng, Zihuan; Ma, Ruicong; Wang, Fan. (2025). Dual-Modified Mannose/RVG29 Peptide-Functionalized Lipid Nanoparticles Loaded With circHIPK2 siRNA Ameliorate Hypoxic-Ischemic Brain Damage in Neonatal Mice by Suppressing Astrocyte Activation.. Journal of integrative neuroscience, 24(12), 45212. https://doi.org/10.31083/JIN45212