The long-term colonization of Helicobacter pylori can cause various gastrointestinal diseases, and its high genetic variability is prone to antibiotic resistance and leads to failure of clinical treatment. Intracellular survival also contributes to the drug tolerance of H. pylori. Patchouli alcohol (PA) shows a highly efficient activity against H. pylori in vitro and in vivo. And this study aims to explore whether PA can reduce the resistance of H. pylori and determine the underlying mechanism. Checkerboard and time–kill bactericidal curve assay reveal that the combination of PA and clarithromycin (CLR) promoted the inhibition and bactericidal effect against H. pylori. Stimulation of CLR leads to the internalization of H. pylori, but PA can effectively inhibit the invasion induced by CLR. Compared with antibiotics, PA remarkably eradicated the intracellular H. pylori, and this intracellular sterilized ability was further improved in combination with antibiotics (CLR and metronidazole). The expression of H. pylori efflux pump genes (hp0605, hp1327, and hp1489) was dose-dependently downregulated by PA. Digital droplet PCR indicated that the H. pylori mutant of A2143G can be inhibited by PA. Cellular uptake and transport assays showed that PA is rapidly absorbed, which promotes its activity against intracellular bacteria. Therefore, PA can act synergistically with CLR as a candidate treatment against drug-resistant H. pylori.

Helicobacter pylori was classified by the World Health Organization as a class 1 carcinogen. The development of drug-resistant strains of this pathogen poses a serious threat to human health worldwide. The cell invasion of H. pylori activates xenophagy in gastric epithelial cells by mediating miR-30b/c, and the emergence of autophagosomes provides a niche that enables the survival of intracellular H. pylori and promotes its drug resistance. This study revealed that some clinical drug-resistant H. pylori strains present much stronger invasive ability than standard strains. Patchouli alcohol (PA), a tricyclic sesquiterpene from Pogostemon cablin (Blanco) Benth (Labiatae), showed reliable activity against intracellular H. pylori. The mechanisms appeared to involve the downregulation of miR-30c-3p/5p and miR-30b-5p, thereby upregulating xenophagy-related gene expression (ULK1, ATG5, ATG12, and ATG14) and enhancing xenophagy. PA also inhibited the nuclear transfection of miR-30b-5p induced by H. pylori, thereby enhancing transcription factor EB function and increasing lysosome activity. The finding of strongly invasive intracellular H. pylori has great implications for clinical treatment, and PA can act against invasive H. pylori based on the improvement of miR-30b/c mediated xenophagy. Taken together, the results demonstrate that PA have potential use as a candidate medication for intracellular drug-resistant H. pylori.

Persistent Helicobacter pylori infection causes a variety of gastrointestinal diseases and even gastric cancer. H. pylori invades gastric epithelial cells to survive and proliferate, which is one of the key factors in persistent colonization. A Published study has confirmed that cells can eliminate intracellular H. pylori through xenophagy to maintain intracellular balance. However, a growing body of evidences indicate that H. pylori can inhibit xenophagy by miRNA through regulating the expression of key autophagy-related genes. Through western blot analysis, mRFP-GFP-LC3 transfection assay, and transmission electron microscopy, we found that H. pylori infection obstructed autophagy flux degradation stage in GES-1 cell lines. Gentamicin protection assay confirmed that inhibit xenophagy is benefit for intracellular H. pylori survive. miR-30c-1-3p and miR-30c-5p were upregulated in GES-1 cell lines after infecting with H. pylori, resulting in the negative regulation on xenophagy. Further studies through bioinformatics analysis and dual-luciferase reporter assays confirmed that ATG14 and ULK1 were the target genes of miR-30c-1-3p and that ATG12 was the target gene of miR-30c-5p. The overexpression of miR-30c-1-3p and miR-30c-5p reduces the expression of ATG14, ULK1, and ATG12 at mRNA level and also decreased intracellular H. pylori elimination in GES-1 cells. The above results suggested that the inhibition on xenophagy by miR-30c-1-3p and miR-30c-5p through ATG14, ULK1, and ATG12 targeting benefitted intracellular H. pylori in the evasion of xenophagy clearance.