Infection with a Hypervirulent Strain of Helicobacter Pylori Primes Gastric Cells Toward Intestinal Transdifferentiation

Abstract

Background: Intestinal metaplasia, gastric-to-intestinal transdifferentiation, occurs as a result of the misexpression of certain regulatory factors, leading to genetic reprogramming. Here, we have evaluated the H. pylori-induced expression patterns of these candidate genes.Methods: The expression levels of 1)tissue-specific transcription factors (RUNX3, KLF5, SOX2, SALL4, CDX1 and CDX2), 2)stemness factors (TNFRSF19, LGR5, VIL1) and 3)tissue-specific mucins (MUC5AC, MUC2) were evaluated by quantitative real-time PCR in gastric primary cells (GPCs), in parallel with two gastric cancer (MKN45 and AGS) cell lines, up to 96h following H. pylori infection. Results: Following H. pylori infection of GPCs, RUNX3 declined at 24h post infection (PI) (-6.2±0.3) and remained downregulated for up to 96h. Subsequently, overexpression of self-renewal and pluripotency transcription factors, KLF5 (3.6±0.2), SOX2 (7.6±0.5) and SALL4 (4.3±0.2) occurred. The expression of TNFRSF19 and LGR5, demonstrated opposing trends, with an early rise of the former (4.5±0.3) at 8h, and a simultaneous fall of the latter (-1.8±0.5). This trend was reversed at 96h, with the decline in TNFRSF19 (-5.5±0.2), and escalation of LGR5 (2.6±0.2) and VIL1 (1.8±0.3). Ultimately, CDX1 and CDX2 were upregulated by 1.9 and 4.7-fold, respectively. The above scenario was, variably observed in MKN45 and AGS cells.Conclusion: Our data suggests an interdependent gene regulatory network, induced by H. pylori infection. This interaction begins with the downregulation of RUNX3, upregulation of self-renewal and pluripotency transcription factors, KLF5, SOX2 and SALL4, leading to the downregulation of TNFRSF19, upregulation of LGR5 and aberrant expression of intestine-specific transcription factors, potentially facilitating the process of gastric-to-intestinal transdifferentiation.