Dimerized TMP-HSA Fusion Protein for Platelet Production

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Solution Overview

Problem

Current therapeutic proteins and peptides, such as thrombopoietin mimetic peptides, have short plasma half-lives, leading to frequent injections and immune responses, which limits their therapeutic efficacy and increases economic burden on patients.

Innovation Solution

A dimerized thrombopoietin mimetic peptide (TMP)-TMP-Human Serum Albumin (HSA) fusion protein is developed, incorporating a dimerization domain to form covalent disulfide bonds, thereby extending the plasma half-life and reducing immune responses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If therapeutic proteins and peptides are used to treat diseases, then therapeutic efficacy is achieved, but plasma half-life is short requiring frequent injections

Engineering Contradiction:
Improveplasma half-lifeVSAvoidinjection frequency
Core Design Contradiction:
Duration of action of moving objectVSProductivity

Solution Approach 1:

The patent creates a fusion protein composite by combining TMP (thrombopoietin mimetic peptide) with HSA (human serum albumin) and a dimerization domain. This composite structure leverages the long circulation half-life of HSA (14-20 days) to extend the plasma half-life of the therapeutic TMP peptide, reducing injection frequency from multiple times weekly to potentially once weekly or less frequently.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges three functional components into a single fusion protein: the therapeutic TMP peptide, the HSA carrier protein, and a dimerization domain. This merging allows the therapeutic peptide to benefit from the pharmacokinetic properties of HSA while maintaining its biological activity, effectively solving the short half-life problem through structural combination rather than frequent administration.

Inventive Principle:
Principle #5Merging (Combining)

2Duration of action of moving object

If mutations are introduced to prolong half-life, then plasma half-life is extended, but antigenicity is strengthened leading to neutralizing antibody production

Engineering Contradiction:
Improveplasma half-lifeVSAvoidantigenicity
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses HSA as an intermediary carrier protein that mediates the delivery of the TMP therapeutic peptide. Instead of mutating the TMP peptide itself (which would increase antigenicity), the HSA intermediary provides the long half-life property while the TMP peptide remains unchanged, preserving its low antigenicity and avoiding neutralizing antibody production.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the molecular weight and structural parameters of the therapeutic peptide by fusing it with HSA. This parameter change (from small peptide to large fusion protein) fundamentally alters the pharmacokinetic profile, extending half-life without changing the antigenic determinants of the TMP peptide, thereby avoiding immune response while achieving prolonged circulation.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If Fc domain is used as carrier protein, then plasma half-life is prolonged, but immune responses are mediated and patent rights are limited

Engineering Contradiction:
Improveplasma half-lifeVSAvoidimmune responses
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the beneficial pharmacokinetic property (long half-life) from HSA without including the problematic immune-mediated functions of the Fc domain. By selecting HSA as the carrier instead of Fc, the invention isolates and utilizes only the circulation extension benefit while eliminating the adverse immune response issue, creating a cleaner therapeutic profile.

Inventive Principle:
Principle #2Taking out (Extraction)

4Duration of action of moving object

If HSA is used as carrier protein, then plasma half-life is prolonged and enzymatic degradation is defended against, but molecular weight and radius of hydration increase reducing renal filtration

Engineering Contradiction:
Improveplasma half-lifeVSAvoidmolecular weight
Core Design Contradiction:
Duration of action of moving objectVSQuantity of substance

Solution Approach 1:

The patent intentionally changes the molecular weight parameter by fusing TMP with HSA (66.5 kDa). This parameter change has two effects: it extends plasma half-life by reducing renal filtration (as desired) and it provides resistance to enzymatic degradation (as beneficial). The invention accepts the molecular weight increase as a necessary trade-off to achieve the therapeutic goal of prolonged half-life and enhanced stability.

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 dimerized TMP-TMP-HSA fusion protein significantly increases platelet counts and ameliorates thrombocytopenia symptoms in mice, providing a long-acting solution for platelet production promotion with reduced immune response.

Implementation Method 1

incorporating a dimerization domain to form covalent disulfide bonds

Methodology Applied
Scientific EffectDisulfide bond formation: Chemical Bonding

Data Source

PatentEP2975062B1Preparation and use of dimerized fusion protein
Publication Date: 2018.07.25 LANZHOU UNIV
  • EP2975062B1 patent drawingFigure 1
  • EP2975062B1 patent drawingFigure 2
  • EP2975062B1 patent drawingFigure 3~4

AI summary

The present invention relates to the preparation of a dimerized TMP-TMP-HSA fusion protein and its application. Said fusion protein is comprised of one HSA and tandem TMP-TMP, which are linked to a dimerization domain by a peptide liker, and the dimerization domain can ensure said fusion protein to be correctly dimerized during its expression. Said tandem TMP-TMP can be linked to an amino terminal or a carboxyl terminal of HSA.