Hydrogel-based delivery of Tat-fused protein Hsp70 protects dopaminergic cells in vitro and in a mouse model of Parkinson’s disease

Abstract

AbstractNeurodegenerative disorders such as Parkinson’s disease (PD) have no effective therapies. However, many promising drugs are precluded from clinical trials because of their poor brain availability. The chaperone protein Hsp70 has been reported to be effective in PD models, but its brain targeting is challenging. We developed a novel brain Hsp70 delivery system using injectable, biocompatible, and biodegradable semi-interpenetrating polymer networks of collagen (COLL) and low-molecular-weight hyaluronic acid (LMW HA) structured with gelatin particles. We produced human recombinant Hsp70-1A fused with the cell-penetrating peptide Tat (Tat-Hsp70) that was neuroprotective in vitro against the dopaminergic toxin 6-hydroxydopamine (6-OHDA). We assessed Tat-Hsp70 release from the selected COLL-LMW HA composites in vitro, observing a 95% release of loaded protein after 96\u2009h. The release kinetics FITTED the Korsmeyer-Peppas model (regression coefficient 0.98) and the released Tat-Hsp70 remained neuroprotective for SH-SY5Y cells. Magnetic resonance imaging revealed that COLL-LMW HA composites lasted at least 96\u2009h at the brain level, and in vivo Tat-Hsp70 release studies indicated that hydrogel presence is pivotal for a spatially focused neuroprotective effect. In an in vivo model of dopaminergic degeneration, Tat-Hsp70-loaded composites conveyed neuroprotection at both the behavioral and dopaminergic neuronal levels against the striatal injection of 6-OHDA. After the injection of Tat-Hsp70-loaded composites, mice showed a transient inflammatory response, with a decrease in GFAP and CD11b immunostaining after 7 days. Our delivery system enabled the effective brain release of Tat-Hsp70 and is ready for further improvements.Parkinson’s disease: Delivery of neuroprotective factors to brain cellsAn injectable, biocompatible and biodegradable system for delivering drugs to the brain, developed by researchers in Italy, could help in the treatment of neurodegenerative disorders. Parkinson’s disease (PD) is characterized by the misfolding of specific proteins in the brain, which then aggregate and become toxic. Heat shock protein 70 (Hsp70) is known to prevent misfolding and aggregation. This makes Hsp70 a potential therapeutic strategy in PD but its delivery to brain cells is challenging because of its low cell membrane permeability. Carmen Giordano, Diego Albani and co-workers fused Hsp70 with a cell-penetrating peptide and embedded in a network of collagen and hyaluronic acid. Experiments also in a mouse model of PD showed that within 96\u2009h more than 95% of the Hsp70 had been released to the dopaminergic neurons affected in PD.We produced a human recombinant Hsp70-1A fused with the cell-penetrating peptide Tat (Tat-Hsp70-1A), that was neuroprotective in vitro against the dopaminergic toxin 6-hydroxydopamine (6-OHDA). We developed and characterized a Tat-Hsp70-1A delivery system by exploiting an injectable, biocompatible, biodegradable semi-interpenetrating polymer network composed of collagen (COLL) and low-molecular-weight hyaluronic acid (LMW HA), structured with gelatin particles. Tat-Hsp70-1A diffused from the selected COLL-LMW HA composites in an active form and protected dopaminergic cells and neurons in Parkinson’s disease (PD) models. Furthermore, Tat-Hsp70-loaded composites conveyed neuroprotection both at behavioral and dopaminergic neuronal level against striatal injection of 6-OHDA.\n