Synthesis of electroneutralized amphiphilic copolymers with peptide dendrons for intramuscular gene delivery

Intramuscular gene delivery materials are of great importance in plasmid-based gene therapy system, but there is limited information so far on how to design and synthesize them. A previous study showed that the peptide dendron-based triblock copolymer with its components arranged in a reversed biomembrane architecture could significantly increase intramuscular gene delivery and expression. Herein, we wonder whether copolymers with biomembrane-mimicking arrangement may have similar function on intramuscular gene delivery. Meanwhile, it is of great significance to uncover the influence of electric charge and molecular structure on the function of the copolymers. To address the issues, amphiphilic triblock copolymers arranged in hydrophilic-hydrophobic-hydrophilic structure were constructed despite the paradoxical characteristics and difficulties in synthesizing such hydrophilic but electroneutral molecules. The as-prepared two copolymers, dendronG2(l-lysine-OH)-poly propylene glycol2k(PPG2k)-dendronG2(l-lysine-OH) (rL2PL2) and dendronG3(l-lysine-OH)-PPG2k-dendronG3(l-lysine-OH) (rL3PL3), were in similar structure but had different hydrophilic components and surface charges, thus leading to different capabilities in gene delivery and expression in skeletal muscle. rL2PL2 was more efficient than Pluronic L64 and rL3PL3 when mediating luciferase, β-galactosidase, and fluorescent protein expressions. Furthermore, rL2PL2-mediated growth-hormone-releasing hormone expression could significantly induce mouse body weight increase in the first 21 days after injection. In addition, both rL2PL2 and rL3PL3 showed good in vivo biosafety in local and systemic administration. Altogether, rL2PL2-mediated gene expression in skeletal muscle exhibited applicable potential for gene therapy. The study revealed that the molecular structure and electric charge were critical factors governing the function of the copolymers for intramuscular gene delivery. It can be concluded that, combined with the previous study, both structural arrangements either reverse or similar to the biomembrane are effective in designing such copolymers. It also provides an innovative way in designing and synthesizing new electroneutralized triblock copolymers, which could be used safely and efficiently for intramuscular gene delivery

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Preparation of core@dual-shell BT@TiO2@PDA nanoparticles and dielectric properties of BT@TiO2@PDA/PI composite films

To improve the interface compatibility, dielectric properties and energy storage density of polyimide(PI)-based composite materials, the core@dual-shell nanoparticles, BT@TiO2@PDA were obtained via facile solution method using the dopamine to coat on the BT@TiO2 nanoparticles, which is barium titanate (BT) coated with amorphous-TiO2, hydrolyzed from tetra-n-butyl titanate (TBT). A series of modified BaTiO3/PI (BT@TiO2@PDA/PI) composites with different contents of BT@TiO2@PDA were prepared through a solution casting film formation method. The results show that the dispersion of nanofillers in the polymer matrix and the interface compatibility between them can be improved by utilizing core@dual-shell nano-structured BaTiO3. The permittivity κ of BT@TiO2@PDA/PI composite films with 40%(mass fraction) filler loading increase to 8.8 (1 kHz), which is about 2.7 times higher than that of pristine polyimide, 1.4 times higher than that of pristine BaTiO3/PI composite films. Temperature-dependent and frequency-dependent dielectric performance tests confirm that BT@TiO2@PDA/PI composites possess good temperature and frequency stability. In the frequency range of 100 kHz, the dielectric loss of the composites is less than 0.010; when the filler loadings are under 40%, the permittivity of the composites decreases by less than 0.6 (1 kHz) from 25 ℃ to 160 ℃

The Progress of Non-Viral Materials and Methods for Gene Delivery to Skeletal Muscle

Since Jon A. Wolff found skeletal muscle cells being able to express foreign genes and Russell J. Mumper increased the gene transfection efficiency into the myocytes by adding polymers, skeletal muscles have become a potential gene delivery and expression target. Different methods have been developing to deliver transgene into skeletal muscles. Among them, viral vectors may achieve potent gene delivery efficiency. However, the potential for triggering biosafety risks limited their clinical applications. Therefore, non-viral biomaterial-mediated methods with reliable biocompatibility are promising tools for intramuscular gene delivery in situ. In recent years, a series of advanced non-viral gene delivery materials and related methods have been reported, such as polymers, liposomes, cell penetrating peptides, as well as physical delivery methods. In this review, we summarized the research progresses and challenges in non-viral intramuscular gene delivery materials and related methods, focusing on the achievements and future directions of polymers

Synthesis of Electroneutralized Amphiphilic Copolymers with Peptide Dendrons for Intramuscular Gene Delivery

Intramuscular gene delivery materials are of great importance in plasmid-based gene therapy system, but there is limited information so far on how to design and synthesize them. A previous study showed that the peptide dendron-based triblock copolymer with its components arranged in a reversed biomembrane architecture could significantly increase intramuscular gene delivery and expression. Herein, we wonder whether copolymers with biomembrane-mimicking arrangement may have similar function on intramuscular gene delivery. Meanwhile, it is of great significance to uncover the influence of electric charge and molecular structure on the function of the copolymers. To address the issues, amphiphilic triblock copolymers arranged in hydrophilic–hydrophobic–hydrophilic structure were constructed despite the paradoxical characteristics and difficulties in synthesizing such hydrophilic but electroneutral molecules. The as-prepared two copolymers, dendronG2­(l-lysine-OH)-poly propylene glycol_2k(PPG_2k)-dendronG2­(l-lysine-OH) (<b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>) and dendronG3­(l-lysine-OH)-PPG_2k-dendronG3­(l-lysine-OH) (<b>rL</b>_<b>3</b><b>PL</b>_<b>3</b>), were in similar structure but had different hydrophilic components and surface charges, thus leading to different capabilities in gene delivery and expression in skeletal muscle. <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b> was more efficient than Pluronic L64 and <b>rL</b>_<b>3</b><b>PL</b>_<b>3</b> when mediating luciferase, β-galactosidase, and fluorescent protein expressions. Furthermore, <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>-mediated growth-hormone-releasing hormone expression could significantly induce mouse body weight increase in the first 21 days after injection. In addition, both <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b> and <b>rL</b>_<b>3</b><b>PL</b>_<b>3</b> showed good in vivo biosafety in local and systemic administration. Altogether, <b>rL</b>_<b>2</b><b>PL</b>_<b>2</b>-mediated gene expression in skeletal muscle exhibited applicable potential for gene therapy. The study revealed that the molecular structure and electric charge were critical factors governing the function of the copolymers for intramuscular gene delivery. It can be concluded that, combined with the previous study, both structural arrangements either reverse or similar to the biomembrane are effective in designing such copolymers. It also provides an innovative way in designing and synthesizing new electroneutralized triblock copolymers, which could be used safely and efficiently for intramuscular gene delivery

Electroneutralized Amphiphilic Triblock Copolymer with a Peptide Dendron for Efficient Muscular Gene Delivery

Hydrophilic–hydrophobic–hydrophilic triblock copolymers, such as Pluronic L64, P85, and P105, have attracted more attention due to their enhancement in muscular gene delivery. In the present study, a new kind of electroneutralized triblock copolymer, LPL, dendron G2­(l-lysine-Boc)-PEG_2k-dendron G2­(l-lysine-Boc), was designed and investigated. This hydrophobic–hydrophilic–hydrophobic copolymer is composed of a structure reverse to that of L64, one of the most effective materials for intramuscular gene delivery so far. Our results showed that LPL exhibited good <i>in vivo</i> biocompatibility after intramuscular and intravenous administration. LPL mediated higher reporter gene expression than L64 in assays of β-galactosidase (LacZ), luciferase, and fluorescent protein E2-Crimson. Furthermore, LPL-mediated mouse growth hormone expression significantly accelerated mouse growth within the first 10 days. Altogether, LPL-mediated gene expression in skeletal muscle exhibits the potential of successful gene therapy. The current study also presented an innovative way to design and construct new electroneutralized triblock copolymers for safe and effective intramuscular gene delivery