Therapeutic effects, immunogenicity and cytotoxicity of a cell penetrating peptide-peptide nucleic acid conjugate against cagA of Helicobacter pylori in cell culture and animal model

Helicobacter pylori causes several gastrointestinal diseases, including asymptomatic gastritis, chronic peptic ulcer, duodenal ulcer, lymphoma of the mucosa-associated lymphoid tissue (MALT), and gastric adenocarcinoma. In recent years, failure to eradicate H. pylori infections has become an alarming problem for physicians. It is now clear that the current treatment strategies may become ineffective, necessitating the development of innovative antimicrobial compounds as alternative treatments.

In this experimental study, a cell-penetrating peptide-conjugated peptide nucleic acid (CPP-PNA) was used to target the cagA expression. cagA expression was evaluated using RT-qPCR assay after treatment by the CPP-PNA in cell culture and animal model. Additionally, immunogenicity and toxicity of the CPP-PNA were assessed in both cell culture and animal models.

Our analysis showed that cagA mRNA levels reduced in H. pylori-infected HT29 cells after treatment with CPP-PNA in a dose-dependent manner. Also, cagA expression in bacterial RNA extracted from stomach tissue of mice treated with PNA was reduced compared to that of untreated mice. The expression of inflammatory cytokines also decreased in cells and tissue of H. pylori-infected mice after PNA treatment. The tested CPP-PNA showed no significant adverse effects on cell proliferation of cultured cells and no detectable toxicity and immunogenicity were observed in mice.

These results suggest the effectiveness of CPP-PNA in targeting CagA for various research and therapeutic purposes, offering a potential antisense therapy against H. pylori infections.