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Induction of CD44 Variant Isoforms is an Early Epithelial Response to Helicobacter pylori Infection
Author(s) -
Chakrabarti Jayati,
Steele Nina,
Holokai Loryn,
Broda Taylor,
Biesiada Jacek,
Pitstick Amy,
Mayhew Christopher,
Medvedovic Mario,
Wells James,
Zavros Yana
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.869.28
Subject(s) - cd44 , helicobacter pylori , cancer research , cancer stem cell , biology , cancer , apoptosis , caga , cancer cell , chronic gastritis , stem cell , microbiology and biotechnology , cell , immunology , gastritis , biochemistry , genetics , virulence , gene
Background Helicobacter pylori (H. pylori) is the major risk factor for the development of gastric cancer. The progression of H. pylori induced chronic inflammation to gastric cancer may result from the aberrant expression of the cancer stem cell marker, CD44 variant isoform 9 (CD44v9). H. pylori induces reactive oxygen species (ROS) that subsequently leads to cell apoptosis via caspase activation. It is reported that in cancer stem cells, CD44v9 stabilizes the cystine‐glutamate transporter xCT, thus promotes resistance to ROS and subsequently leads to tumor growth. However, it is unknown whether CD44v9 protects the gastric epithelium against H. pylori ‐induced apoptosis during early infection. In addition, CD44 variant isoform 6 (CD44v6), is not only a biomarker for diffuse‐type gastric cancer, but also promotes H. pylori‐ induced epithelial cell proliferation. Hypotheses H. pylori ‐induced CD44v9 is an early epithelial response to infection that subsequently promotes resistance to ROS‐induced epithelial cell apoptosis. Methods Antral and fundic gastric organoids were generated from induced pluripotent stem cell (IPSC) lines derived from the whole blood of normal patients (HGOs). HGOs were microinjected with the H. pylori G27 or a cagA mutant strain. After 72 hr of infection organoids were immunostained for CD44v9, CD44v6 and H. pylori . The expression of IL‐8 and caspase 3 were measured by qRT‐PCR. In a separate series of experiments, infected organoids were treated with either vehicle or 300 mM sulfasalazine (SSZ) for 72 hrs and changes in phosphorylation (activation) of p38 MAPK , a downstream target of ROS was measured by western blot. RNA was isolated from uninfected and infected antral and fundic HGOs and RNA‐sequencing was performed to analyze differential expression of genes among those samples. Results H. pylori induced the expression of CD44v9 and CD44v6 in HGOs and this correlated with the suppression of caspase 3 and increased IL‐8 gene expression. Despite the Increased expression of ROS observed in H. pylori Infected HGOs, there was increased epithelial cell proliferation within the infected organoids. Proliferation significantly decreased in H. pylori infected HGOs treated with xCT inhibitor SSZ. H. pylori infected fundic HGOs showed 94% dissimilarity in the differentially expressed genes compared to infected antral HGOs, which fall mostly in cancer and apoptotic pathways. Conclusion Induction of CD44v9 and v6 are early epithelial changes in response to H. pylori infection, and may play a role in the protection against H. pylori ‐induced apoptosis Support or Funding Information This work was supported by NIH 1U19AI116491‐01 (Weis and Wells, YZ Project Leader), This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .