A Therapeutic Peptide Vaccine Against PCSK9

Area of Science:

• Biochemistry
• Immunology
• Pharmacology

Background:

• Hypercholesterolemia is a significant risk factor for cardiovascular diseases.
• Current treatments for hypercholesterolemia have limitations in efficacy and patient compliance.
• Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of cholesterol metabolism, making it a therapeutic target.

Purpose of the Study:

• To screen and develop effective virus-like particle (VLP)-peptide vaccines targeting PCSK9 for hypercholesterolemia treatment.
• To evaluate the efficacy and safety of a lead VLP-PCSK9 peptide vaccine candidate, PCSK9Qβ-003.

Main Methods:

• Screening of VLP-peptide vaccines targeting specific regions of PCSK9 based on defined criteria (location, host proteome similarity, antigenicity, hydrophilicity, functional mutation sites).
• Vaccination of mice (Balb/c and LDLR+/-) with selected VLP-PCSK9 peptide vaccines.
• Assessment of antibody titers, plasma cholesterol levels, PCSK9 levels, hepatic LDLR expression, and key lipid metabolism-related gene expression (SREBP-2, HNF-1α, HMG-CoA reductase).
• Evaluation of immune injury in vaccinated animals.

Main Results:

• VLP-PCSK9 peptide vaccines, particularly PCSK9Qβ-003, induced high-titer IgG antibodies against PCSK9 in mice.
• PCSK9Qβ-003 significantly reduced plasma total cholesterol in both mouse models.
• PCSK9Qβ-003 decreased plasma PCSK9 levels and increased hepatic LDLR expression.
• PCSK9Qβ-003 up-regulated SREBP-2, HNF-1α, and HMG-CoA reductase in LDLR+/- mice, indicating modulation of lipid homeostasis.
• No significant immune injury was observed in vaccinated animals.

Conclusions:

• The PCSK9Qβ-003 vaccine is a promising therapeutic candidate for hypercholesterolemia.
• This VLP-PCSK9 vaccine effectively lowers cholesterol by reducing PCSK9 levels and enhancing LDLR-mediated cholesterol clearance.
• The vaccine demonstrates a favorable safety profile and potential for regulating lipid homeostasis.