Decreased SLC26A3 expression and function in intestinal epithelial cells in response to Cryptosporidium parvum infection

Abstract

The protozoan parasite Cryptosporidium parvum (CP) causes cryptosporidiosis, a diarrheal disease worldwide. Infection in immunocompetent hosts typically results in acute, self-limiting, or recurrent diarrhea. However, in immunocompromised individuals infection can cause fulminant diarrhea, extraintestinal manifestations, and death. To date, the mechanisms underlying CP-induced diarrheal pathogenesis are poorly understood. Diarrheal diseases most commonly involve increased secretion and/or decreased absorption of fluid and electrolytes. We and others have previously shown impaired chloride absorption in infectious diarrhea due to dysregulation of SLC26A3 [downregulated in adenoma (DRA)], the human intestinal apical membrane Cl−/[Formula: see text] exchanger protein. However, there are no studies on the effects of CP infection on DRA activity. Therefore, we examined the expression and function of DRA in intestinal epithelial cells in response to CP infection in vitro and in vivo. CP infection (0.5 × 106 oocysts/well in 24-well plates, 24 h) of Caco-2 cell monolayers significantly decreased Cl−/[Formula: see text] exchange activity (measured as DIDS-sensitive 125I uptake) as well as DRA mRNA and protein levels. Substantial downregulation of DRA mRNA and protein was also observed following CP infection ex vivo in mouse enteroid-derived monolayers and in vivo in the ileal and jejunal mucosa of C57BL/6 mice for 24 h. However, at 48 h after infection in vivo, the effects on DRA mRNA and protein were attenuated and at 5 days after infection DRA returned to normal levels. Our results suggest that impaired chloride absorption due to downregulation of DRA could be one of the contributing factors to CP-induced acute, self-limiting diarrhea in immunocompetent hosts.

Stem cell‐derived enteroid cultures as a tool for dissecting host‐parasite interactions in the small intestinal epithelium

“…Although diarrhoeal disease is usually associated with the disruption of ion transport, DRA dysregulation in Cryptosporidium infection has not been described until recently. DRA was shown to be downregulated in Caco‐2 cells and then confirmed in the physiologically relevant models, murine enteroid‐derived monolayers and in vivo in C57BL/6 mice 23 …”

“…Enteroid models have recently been applied to the study of T gondii and Cryptosporidium spp, yielding important biological insights 14,16‐25 . Since enteroids recreate many of the characteristics of the in vivo environment in a sustainable and cost‐effective way, they pave the way for a reduction in the use of animals in research into these important parasites.…”

Global profiling of lncRNAs-miRNAs-mRNAs reveals differential expression of coding genes and non-coding RNAs in the lung of beagle dogs at different stages of Toxocara canis infection

“…SLC26A3 mediates intestinal NaCl absorption and is downregulated in inflammatory bowel disease-associated diarrhea (Chatterjee et al, 2017). Impaired chloride absorption caused by downregulation of slc26a3 contributed to Cryptosporidium parvum-induced acute and self-limiting diarrhea (Kumar et al, 2019). The expression of slc26a3 at 96 h p.i.…”

Cryptosporidium parvum infection induces autophagy in intestinal epithelial cells

“…CP oocysts for treatment were obtained from Waterborne Inc. (New Orleans, LA). Caco‐2 cells were treated with live oocysts for 24 hr as previously described by us (Kumar et al, 2018; Kumar et al, 2019). Briefly, excystation was performed by incubating the oocysts in 20% bleach solution (4:1 vol/vol) for 10 min at room temperature.…”

“…The pathophysiology of cryptosporidiosis is mostly unknown limiting the scope for identifying novel targets for intervention. We have recently shown CP‐induced dysregulation of intestinal barrier function (Kumar et al, 2018) and ion transport (Kumar et al, 2019), which could be important contributors to CP‐induced diarrhoea. In the current study, we provide evidence for induction of autophagy in response to CP infection in IECs, which could, via manipulation of host signalling; have an important role in its pathogenesis.…”