Molecular characterization of sequence-driven peptide glycation

Peptide glycation is an important, yet poorly understood reaction not only found in food but also in biological systems. The enormous heterogeneity of peptides and the complexity of glycation reactions impeded large-scale analysis of peptide derived glycation products and to understand both the contributing factors and how this affects the biological activity of peptides. Analyzing time-resolved Amadori product formation, we here explored site-specific glycation for 264 peptides. Intensity profiling together with in-depth computational sequence deconvolution resolved differences in peptide glycation based on microheterogeneity and revealed particularly reactive peptide collectives. These peptides feature potentially important sequence patterns that appear in several established bio- and sensory-active peptides from independent sources, which suggests that our approach serves system-wide applicability. We generated a pattern peptide map and propose that in peptide glycation the herein identified molecular checkpoints can be used as indication of sequence reactivity.

Codon arrangement modulates MHC-I peptides presentation: implications for a SARS-CoV-2 peptide-based vaccine

SummaryAmong various vaccination strategies, peptide-based vaccines appear as excellent candidates because they are cheap to produce, are highly stable and harbor low toxicity. However, predicting which MHC-I Associated Peptide (MAP) will ultimately reach cell surface remains challenging, due to high false discovery rates. Previously, we demonstrated that synonymous codon arrangement (usage and placement) is predictive of, and modulates MAP presentation. Here, we apply CAMAP (Codon Arrangement MAP Predictor), the artificial neural network we used to unveil the role of codon arrangement in MAP presentation, to predict SARS-CoV MAPs. We report that experimentally identified SARS-CoV-1 and SARS-CoV-2 MAPs are associated with significantly higher CAMAP scores. Based on CAMAP scores and binding affinity, we identified 48 non-overlapping MAP candidates for a peptide-based vaccine, ensuring coverage for a high proportion of HLA haplotypes in the US population (>78%) and SARS-CoV-2 strains (detected in >98% of SARS-CoV-2 strains present in the GISAID database). Finally, we built an interactive web portal (https://www.epitopes.world) where researchers can freely explore CAMAP predictions for SARS-CoV-1/2 viruses. Collectively, we present an analysis framework that can be generalizable to empower the rapid identification of virus-specific MAPs, including in the context of an emergent virus, to help accelerate target identification for peptide-based vaccine designs that could be critical in safely attaining group immunity in the context of a global pandemic.

Formulation, Characterization and Evaluation against SH-SY5Y Cells of New Tacrine and Tacrine-MAP Loaded with Lipid Nanoparticles

Tacrine (TAC) was the first FDA approved drug for the treatment of Alzheimer’s disease, resulting in increased memory and enhanced cognitive symptoms in patients. However, long-term therapy presents poor patient compliance associated with undesired side effects such as nausea, vomiting and hepatoxicity. To improve its therapeutic efficacy and decrease toxicity, the use of nanoparticles could be applied as a possible solution to delivery TAC. In this context, a project has been designed to develop a new nanostructured lipid carrier (NLC) as a delivery system for TAC and conjugate TAC and model amphipathic peptide (MAP) to decrease TAC limitations. Different formulations loaded with TAC and TAC + MAP were prepared using a combination of Compritol 888 ATO as the solid lipid and Transcutol HP as the liquid lipid component. Physical characterization was evaluated in terms of particle size, surface charge, encapsulation efficiency and in vitro drug release studies. Particle size distributions within the nanometer range were obtained with encapsulation efficiencies of 72.4% for the TAC and 85.6% for the TAC + MAP conjugate. Furthermore, cytotoxicity of all NLC formulations was determined against neuroblastoma cell line SH-SY5Y. The optimized TAC delivery system revealed low toxicity suggesting this could be a potential carrier system to deliver TAC. However, TAC + MAP conjugated even encapsulated in the NLC system demonstrated toxicity against the SH-SY5Y cell line.

A multiepitope peptide vaccine against HCV stimulates neutralizing humoral and persistent cellular responses in mice

Background Although DAAs hold promise to significantly reduce rates of chronic HCV infections, its eradication still requires development of an effective vaccine. Prolonged T cell responses and cross neutralizing antibodies are ideal for vaccination against the infection. We aimed to design and synthesize a 6 multi epitope peptide vaccine candidate and provide evidence for production of extended cellular and neutralizing Abs in mice. Methods Six peptides derived from conserved epitopes in E1, E2 (n = 2),NS4B, NS5A and NS5B were designed, synthesized in a multiple antigenic peptide (MAP) form and administered w/o adjuvant to BALB/c mice as HCVp6-MAP at doses ranging from 800 ng to 16 μg. Humoral responses to structural epitopes were assayed by ELISA at different times after injection. ELISpot assay was used to evaluate IFN ɣ producing CD4+/ CD8+ T- lymphocytes at extended durations i.e. > 20 weeks. Viral neutralization by mice sera was tested for genotypes 2a (JFH1) and a chimeric 2a/4a virus (ED43/JFH1) in HCVcc culture. Results HCVp6-MAP confers potent viral neutralization and specific cellular responses at > 1600 ng/ animal for at least 20 weeks. Conclusion We report on a promising anti HCV vaccine for future studies on permissive hosts and in clinical trials.

Effect of muramyl dipeptide and alum adjuvants on immunization with Filarial multi antigen peptide vaccine in mice model

SummaryFilarial thioredoxin and transglutaminase are enzymes that are secreted throughout the lifecycle of the parasites which are mandatory for the survival of the parasite. They are reported to be promising vaccine candidates, yet the limitation factors of these proteins to be developed as vaccines is their homology they share with the host proteins. Hence immunodominant epitopes from these proteins were constructed as peptides and immunised in mice model with Muramyl dipeptide (MDP) as adjuvant. Immunodominant epitopic portions from Filarial thioredoxin and transglutaminase which are non-homologous with host proteins were constructed as Multi Antigen Peptide (MAP) and assembled in an inert lysine core. The synthesised MAP was immunised with MDP as adjuvant in Balb/c mice model, humoral and cellular immune response were studied. Antibody titre levels for TT MAP with MDP was in par with alum as adjuvant in mice models. T cell responses of TT MAP with MDP showed a balanced TH1/TH2 response. The TH1 cytokines namely IL-2 and IFN-ɤ were also higher in TT MAP immunised groups with MDP as adjuvant whereas alum immunised groups was TH2 biased. TT MAP admixed with MDP as adjuvant proves to be safe in mice model. Further vaccination studies are underway in permissive animal models to determine the role of TT MAP with MDP as adjuvant in protective immunity againstW. bancroftiandB. malayiinfections.