Effect of Native Gastric Mucus on in vivo Hybridization Therapies Directed at Helicobacter pylori

Abstract

Helicobacter pylori infects more than 50% of the worldwide population. It is mostly found deep in the gastric mucus lining of the stomach, being a major cause of peptic ulcers and gastric adenocarcinoma. To face the increasing resistance of H. pylori to antibiotics, antimicrobial nucleic acid mimics are a promising alternative. In particular, locked nucleic acids (LNA)/2'-OMethyl RNA (2'OMe) have shown to specifically target H. pylori, as evidenced by in situ hybridization. The success of in vivo hybridization depends on the ability of these nucleic acids to penetrate the major physical barriers—the highly viscoelastic gastric mucus and the bacterial cell envelope. We found that LNA/2'OMe is capable of diffusing rapidly through native, undiluted, gastric mucus isolated from porcine stomachs, without degradation. Moreover, although LNA/2'OMe hybridization was still successful without permeabilization and fixation of the bacteria, which is normally part of in vitro studies, the ability of LNA/2'OMe to efficiently hybridize with H. pylori was hampered by the presence of mucus. Future research should focus on developing nanocarriers that shield LNA/2'OMe from components in the gastric mucus, while remaining capable of diffusing through the mucus and delivering these nucleic acid mimics directly into the bacteria.

Intracellular delivery of oligonucleotides in Helicobacter pylori by fusogenic liposomes in the presence of gastric mucus

“…Finally, we assessed if the PEGylated lipoplexes could still successfully deliver functional NAMs in H. pylori in the presence of gastric mucus. [24] and [49]).…”

“…Importantly, they should do so without losing their activity. Indeed, we have recently shown that interactions with gastric mucus can significantly compromise the ability of NAMs to hybridize with Helicobacter pylori (H. pylori) [24].…”

“…Based on our previous work, locked nucleic acids (LNA) and 2'-OMethyl RNA (2'OMe), with either phosphodiester (PO) or phosphorothioate (PS) as backbone linkages (Figure 1b), were used as NAMs to hybridize to H. pylori rRNA [24,49]. Electrostatic complexes between (anionic) NAMs and (cationic) DOTAP-DOPE liposomes were formed, which were further modified by post-insertion of PEG-lipids with the aim to improve the stability and mobility of the complexes in the harsh gastrointestinal environment [50,51].…”

Helicobacter pylori antibiotic resistance in Portugal: Systematic review and meta‐analysis

“…Helicobacter pylori (Hp) is an important pathogen that colonizes the human gastric mucosa. It is responsible for gastritis, gastroduodenal ulcer disease, gastric adenocarcinoma, mucosa‐associated lymphoid tissue (MALT) lymphoma and may also have a role in some extradigestive conditions . Although infected patients may not have preneoplastic lesions, the progression to cancer is still possible.…”

“…It is responsible for gastritis, gastroduodenal ulcer disease, gastric adenocarcinoma, mucosa-associated lymphoid tissue (MALT) lymphoma and may also have a role in some extradigestive conditions. [1][2][3] Although infected patients may not have preneoplastic lesions, the progression to cancer is still possible. Therefore, it is extremely important to eradicate Hp infection.…”