Pectic galactan based gene delivery system for preventing brain damage in central nervous system injuries

Nitsa Buaron ¹ Antonella Mangraviti ² Francesco Volpin ² Ann Liu ² Mariangela Pedone ² Eric Sankey ² Dina Aranovich ¹ Itay Adar ¹ Fausto Rodriguez ³ Abraham Nyska ⁴ Riki Goldbart ¹ Tamar Traitel ¹ Henry Brem ² Betty Tyler ² Joseph Kost ¹

¹Department of Chemical Engineering, Ben-Gurion University of the Negev, Israel
²Department of Neurosurgery, Johns Hopkins University School of Medicine, USA
³Department of Pathology, Johns Hopkins University School of Medicine, USA
⁴Sackler School of Medicine, Tel Aviv University, Israel

Neuroinflammation is a process involved in response to central nervous system (CNS) injuries and is found in neurodegenerative disorders. Uninhibited or extensive pro-inflamatory response can results in neurotoxicity causing neuronal damage, leading to chronic neurodegeneration. Targeting neuroinflammation has gained great attention recently as a therapeutic strategy for reducing brain damage in CNS injuries.

In this study, a novel pectic-galactan (PG) polysaccharide-based gene therapy approach is developed for targeting reactive gliosis in neuroinflammation. Galectin-3 (Gal-3) is a cell protein with high affinity to β-galactoside sugars. Since it is highly expressed in reactive gliosis and is strongly associated with the pro-inflammatory state of neuroinflammation, we innovatively utilized this unique feature for selective targeting of these cells. PG carries galactans, therefore, can potentially target reactive gliosis via specific carbohydrate interaction between galactan and Gal-3 on the cell membrane, and can be utilized as a carrier for delivering genes to these cells. We hypothesize that PG-based complexes can selectively target reactive gliosis in-vivo through specific binding to overexpressed Gal-3. This targeting will enable the delivery of genes to cells undergoing reactive gliosis, allowing genetic manipulation of the pro-inflammatory state of the cells.

The carrier is synthesized by modifying quaternary ammonium groups on the PG. The resulting quaternized-PG (QPG) is found to form complexes with plasmid DNA with the characteristics required for targeted gene therapy, including high load of plasmid per complex, binding capability to Gal-3, and specific targeting Gal-3 overexpressing cells in-vitro. Gene transfection efficiency was shown in-vivo in rodent model, and histological examination revealed GFP-positive expressing cells mainly in the gliosis layer of induced cortical lesion, indicating that the delivery system was able to selectively transfect the targeted cells which overexpress Gal-3. [Buaron et al.,Carbohydr.Polym.2016][Buaron et al.,Adv.Funct.Mater.2021]

The results confirm that this QPG delivery system is effective in targeting and transfecting neuroinflammation in-vivo. Therefore, can serve as a promising platform for delivering genetic factors for modulating neuroinflammation and accordingly reduce neuronal damage in CNS injuries.