Downregulation of Mouse Intestinal Na⁺-coupled Glucose Transporter SGLT1 by Gum Arabic (Acacia Senegal)

Abstract

Intestinal Na⁺-coupled glucose transporter SGLT1 determines the rate of glucose transport, which in turn influences glucose-induced insulin release and development of obesity. The present study explored effects of Gum Arabic (GA), a dietary polysaccharide from dried exudates of Acacia Senegal, on intestinal glucose transport and body weight in wild-type C57Bl/6 mice. Treatment with GA (100 g/l) in drinking water for four weeks did not affect intestinal SGLT1 transcript levels but decreased SGLT1 protein abundance in jejunal brush border membrane vesicles. Glucose-induced jejunal short-circuit currents revealed that GA treatment decreased electrogenic glucose transport. Drinking a 20% glucose solution for four weeks significantly increased body weight and fasting plasma glucose concentrations, effects significantly blunted by simultaneous treatment with GA. GA further significantly blunted the increase in body weight, fasting plasma glucose and fasting insulin concentrations during high fat diet. In conclusion, the present observations disclose a completely novel effect of gum arabic, i.e. its ability to decrease intestinal SGLT1 expression and activity and thus to counteract glucose-induced obesity.

Renal and Extrarenal Effects of Gum Arabic (Acacia Senegal) - What Can be Learned from Animal Experiments?

“…GA treatment has been shown to decrease intestinal Na + coupled glucose transport by downregulating the Na + coupled glucose carrier SGLT1 [44], which determines the rate of intestsinal glucose absorption [45] and thus influences glucose-induced insulin release and development of obesity (Fig. 3).…”

“…3). Addition of GA to the drinking water of C57Bl/6 mice significantly decreased SGLT1 protein abundance in jejunal and ileal brush border membrane vesicles [44]. According to gene array data, GA does not decrease SGLT1 protein expression by inhibiting SGLT1 transcription but modies SGLT1 abundance rather by modifying posttranscriptional regulation [44].…”

“…Addition of GA to the drinking water of C57Bl/6 mice significantly decreased SGLT1 protein abundance in jejunal and ileal brush border membrane vesicles [44]. According to gene array data, GA does not decrease SGLT1 protein expression by inhibiting SGLT1 transcription but modies SGLT1 abundance rather by modifying posttranscriptional regulation [44]. Besides altered transcription [46] or mRNA stability [47], SGLT1 could be modified by trafficking into the plasma membrane [48] or by direct regulation of transporter activity [49].…”

“…SGLT1 activity is further subject to downregulation by the 67-kDa-protein RS1 [60,61]. According to gene array analysis, decreased SGLT1 protein abundance following GA treatment could be secondary to enhanced expression of SGLT1 inhibitor RS1 (encoded by rsc1a1) [60] or downregulation of SGLT1 stimulator SGK3 [44]. …”

The Effect of Gum Arabic on Energy Balance Genes in Mouse Liver

“…In addition, the dietary fiber was promoting satiety and satiation, alter glycaemic index, affects gastric emptying, stomach hormone secretion and reduces weight [25]. Moreover, Gum Arabic inhibits absorption of glucose in the intestine via interaction with membrane abundance of SGLT1 in mice [35].…”