Protamine/RNA Nanoparticles for Controlled IFN-alpha Production

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Solution Overview

Problem

Current RNA-based immunostimulating compositions face challenges due to instability, toxicity, and the formation of heterogeneous aggregates, which are not suitable for clinical use and can trigger adverse immune responses, and they often induce excessive production of inflammatory cytokines like TNF-alpha, posing safety concerns.

Innovation Solution

The development of protamine/RNA nanoparticles of defined average size, produced by diluting RNA and protamine in low ionic strength solutions, which form homogenous particles suitable for pharmaceutical formulations and controlled immunostimulation, preferentially inducing IFN-alpha production while minimizing TNF-alpha production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RNA is delivered using cationic lipids or PEI, then RNA protection and delivery efficiency are improved, but toxicity increases and heterogeneous aggregates form

Engineering Contradiction:
ImproveRNA protection and delivery efficiencyVSAvoidtoxicity and heterogeneous aggregate formation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the delivery system by replacing cationic lipids and PEI with protamine, a natural cationic protein. This parameter change maintains RNA complexation capability while eliminating the toxicity and aggregate formation associated with synthetic cationic materials. The protamine-RNA complexes form homogeneous nanoparticles with controlled size distribution, resolving the contradiction between delivery efficiency and toxicity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses protamine, a naturally occurring, biodegradable protein, instead of stable but toxic synthetic cationic lipids or PEI. Protamine is rapidly cleared from the body and does not accumulate, making it a safer, disposable-like delivery vehicle that maintains effectiveness without long-term toxicity concerns.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Power

If CpG ODN or bacterial DNA is used for immunostimulation, then immune system activation is improved, but severe side effects occur due to over-stimulation

Engineering Contradiction:
Improveimmune system activationVSAvoidsevere side effects and splenomegaly
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The invention converts the inherent immunostimulatory property of RNA into a controlled benefit by using protamine complexation to modulate the immune response. Instead of uncontrolled over-stimulation by CpG ODN or bacterial DNA, the protamine-RNA nanoparticles provide controlled activation of Toll-like receptors, transforming the potential harm of excessive immune activation into a beneficial, controlled immunostimulatory effect.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Protamine acts as an intermediary between the RNA immunostimulant and the immune system. The protamine-RNA complex modulates the interaction, providing controlled immune activation through Toll-like receptor engagement while avoiding the severe over-stimulation effects of direct CpG ODN or bacterial DNA administration.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If DNA molecules are administered, then immunostimulation is achieved, but DNA degradation is slow leading to auto-antibody formation

Engineering Contradiction:
ImproveimmunostimulationVSAvoidDNA persistence in bloodstream
Core Design Contradiction:
PowerVSDuration of action of stationary object

Solution Approach 1:

The invention uses RNA instead of DNA as the immunostimulant payload. RNA is naturally less stable and more rapidly degraded than DNA in the bloodstream, preventing long-term persistence and auto-antibody formation. The protamine coating provides temporary protection during delivery, after which the RNA is rapidly cleared, achieving the desired immunostimulation without prolonged exposure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Strength

If protamine and RNA are mixed in high salt conditions, then complexation occurs, but large heterogeneous aggregates form that are not injectable

Engineering Contradiction:
ImprovecomplexationVSAvoidparticle size homogeneity and injectability
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention applies preliminary action by controlling the ionic strength of the buffer conditions during protamine-RNA complex formation. By using low ionic strength buffers (e.g., 10 mM sodium acetate, pH 5.0) during the complexation step, the invention prevents premature aggregation and ensures formation of homogeneous nanoparticles before administration, making the final product injectable.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical-chemical parameters of the complexation environment by using low ionic strength conditions rather than high salt conditions. This parameter change controls the electrostatic interactions between protamine and RNA, preventing uncontrolled aggregation and ensuring formation of homogeneous, injectable nanoparticles with consistent size distribution.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The nanoparticles achieve controlled immunostimulation with enhanced IFN-alpha production and reduced TNF-alpha levels, are injectable, and can be used for various diseases, including cancer and viral infections, with a precise immune response modulation.

Implementation Method 1

protamine/RNA nanoparticles... produced by diluting RNA and protamine in low ionic strength solutions, which form homogenous particles

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Data Source

PatentEP2772251B1Protamine/RNA nanoparticles for immunostimulation
Publication Date: 2021.03.03 UNIVERSITY OF ZURICH
  • EP2772251B1 patent drawingFigure 1A
  • EP2772251B1 patent drawingFigure 1B
  • EP2772251B1 patent drawingFigure 1C

AI summary

The present invention relates to protamine/RNA nanoparticles of defined average size, a pharmaceutical composition containing said nanoparticles and to a method of producing the same. The nanoparticles of the present invention are particularly useful as an immunostimulating medicament with a precise pattern of immunostimulation different from the prior art.