Autophagy inducing cyclic peptides constructed by methionine alkylation

Programmable Stapling Peptide Based on Sulfonium as Universal Vaccine Adjuvants for Multiple Types of Vaccines

Adjuvants are non-specific immune enhancers commonly used to improve the responsiveness and persistence of the immune system toward antigens. However, due to the undefined chemical structure, toxicity, non-biodegradability, and lack of design technology in many existing adjuvants, it remains difficult to achieve substantive breakthroughs in the adjuvant research field. Here, a novel adjuvant development strategy based on stapling peptides is reported to overcome this challenge. The nano-vaccine incorporating peptide adjuvant and recombinant HBsAg protein not only induced strong antibody titers that are equivalent to aluminum adjuvanted vaccines but also simultaneously activated T-cell immune response. Similar results are also observed in herpes zoster vaccine and more complex influenza vaccine. The mechanism analysis demonstrates that antigen is efficiently carried into antigen-presenting cells (APCs) by peptide, further promoting the secretion of cytokines and activation of APCs. In addition, by redesigning the adjuvant, it is found that the sulfonium centers, rather than the sequence of peptide played an important role in immune activation. This discovery may provide a new paradigm for the rational design of peptide-based adjuvants. In brief, this study demonstrates that stapling peptides with sulfonium centers can provide a well-defined, programmable, biocompatible, and effective adjuvant for multiple types of vaccines.

Configuration of two cysteine residues in a ring within a stapled Bim peptide affects the secondary structure and apoptotic activity

Many reports have shown that stabilization of secondary structure by stapling functional peptides enhances the intracellular bioactivity. However, no report has discussed the correlation between stabilization and biological activity based on the configuration of amino acid residues used as anchors for stapling. To clarify this, we investigated the helix content and apoptotic efficiency of an apoptosis-inducing peptide, Bim, and four stapled Bim peptides containing stapling-related Cys residues introduced with different configurations within the sequence. The results demonstrated that the configuration of Cys residues in stapled Bim peptides affected the secondary structure and intracellular activity of the peptides, and furthermore, there was a correlation between these latter two variables.

Development of an autophagy activator from Class III PI3K complexes, Tat-BECN1 peptide: Mechanisms and applications

Impairment or dysregulation of autophagy has been implicated in many human pathologies ranging from neurodegenerative diseases, infectious diseases, cardiovascular diseases, metabolic diseases, to malignancies. Efforts have been made to explore the therapeutic potential of pharmacological autophagy activators, as beneficial health effects from caloric restriction or physical exercise are linked to autophagy activation. However, the lack of specificity remains the major challenge to the development and clinical use of autophagy activators. One candidate of specific autophagy activators is Tat-BECN1 peptide, derived from Beclin 1 subunit of Class III PI3K complexes. Here, we summarize the molecular mechanisms by which Tat-BECN1 peptide activates autophagy, the strategies for optimization and development, and the applications of Tat-BECN1 peptide in cellular and organismal models of physiology and pathology.

Oxidation and ATP dual-responsive block copolymer containing tertiary sulfoniums: self-assembly, protein complexation and triggered release

Alkylation of thioether-containing block copolymer simultaneously incorporated sulfoniums and phenylboronic acid moieties. The co-assembly of this cationic polymer and protein generated micelles with an H₂O₂-and ATP-responsive release profile.

Intramolecular methionine alkylation constructs sulfonium tethered peptides for protein conjugation

Continuous efforts have been invested in the selective modification of proteins.