Role of ST6GAL1 and ST6GAL2 in subversion of cellular signaling during enteroaggregative Escherichia coli infection of human intestinal epithelial cell lines

Abstract

Emerging evidence have suggested that aberrant sialylation on cell-surface carbohydrate architecture may influence host–pathogen interactions. The α2,6-sialyltransferase (ST) enzymes were found to alter the glycosylation pattern of the pathogen-infected host cell-surface proteins, which could facilitate its invasion. In this study, we assessed the role of specific α2,6-ST enzymes in the regulation of enteroaggregative E. coli (EAEC)–induced cell signaling pathways in human intestinal epithelial cells. EAEC-induced expression of α2,6-ST family genes in HCT-15 and INT-407 cell lines was assessed at mRNA level by qRT-PCR. Specific esi-RNA was used to silence the target ST-gene in each of the EAEC-infected cell type. Subsequently, the role of these enzymes in regulation of EAEC-induced cell signaling pathways was unraveled by analyzing the expression of MAPkinases (ERK1/2, p38, JNK) and transcription factors (NFκB, cJun, cFos, STAT) at mRNA and protein levels by qRT-PCR and western immunoblotting, respectively, expression of selected sialoglycoproteins by western immunoblotting along with the secretory IL-8 response using sandwich ELISA. ST6GAL-1 and ST6GAL-2 were efficiently silenced in EAEC-infected HCT-15 and INT-407 cells, respectively. Significant reduction in EAEC-induced activation of MAPKs, transcription factors, sialoglycoproteins, and IL-8 secretion was noted in ST-silenced cells in comparison to the respective control cells. We propose that ST6GAL-1 and ST6GAL-2 are quintessential for EAEC-induced stimulation of MAPK-mediated pathways, resulting in activation of transcription factors, leading to an inflammatory response in the human intestinal epithelial cells. Our study may be helpful to design better therapeutic strategies to control EAEC- infection. Key points • EAEC induces α2,6-sialyltransferase (ST) upregulation in intestinal epithelial cells • Target STs (ST6GAL-1 & ST6GAL-2) were efficiently silenced using specific esiRNAs • Expression of MAPKs, transcription factors & IL-8 was reduced in ST silenced cells Graphical Abstract Supplementary Information The online version contains supplementary material available at 10.1007/s00253-022-12321-2.

Dynamic Interactions between Diarrhoeagenic Enteroaggregative Escherichia coli and Presumptive Probiotic Bacteria: Implications for Gastrointestinal Health

“…The comprehensive exploration of EAEC pathogenicity, coupled with an in-depth analysis of its interaction with IL-8, yields valuable insights into the delicate balance governing gastrointestinal health. This understanding opens potential avenues for therapeutic interventions aimed at restoring equilibrium within the intricate host-pathogen interplay [23,25]. Beyond its role in infection, IL-8 holds significant implications for gastrointestinal health [26].…”

“…In the intricate landscape of gastrointestinal infections, IL-8 takes centre stage as a central player, initiating an inflammatory response to combat invading pathogens [23,24]. Particularly within the context of EAEC infections, IL-8 s role becomes pronounced, influencing the severity and duration of the inflammatory cascade within the gastrointestinal tract [23,25]. The comprehensive exploration of EAEC pathogenicity, coupled with an in-depth analysis of its interaction with IL-8, yields valuable insights into the delicate balance governing gastrointestinal health.…”