Journal: Translational Pediatrics

Article Title: Chenodeoxycholic acid activates the TGR5/TRPA1-5-HT pathway to regulate intestinal motility in breastfed infants and mouse models

doi: 10.21037/tp-2025-100

Figure Lengend Snippet: Impact of increasing concentrations of CDCA enemas on intestinal motility, fecal characteristics, colonic histology, and expression of serotonin pathway components. Mice received CDCA at different concentrations (Control, 5, 10, 20, and 40 mg/kg) via enema for 7 consecutive days and were then analyzed. (A) Representative images of GI transit distance after gavage of carmine red solution for 30 minutes, showing dose-dependent increases in transit. The red arrow points to the area reached by carmine red. (B) Representative images of fecal appearance, demonstrating increased water content with higher CDCA doses. (C) Quantitative measurements of fecal water content, GI transit time, and colonic transit distance after gavage of carmine red solution for 60 minutes. (D) Representative images of HE-stained ileum tissue sections showing no significant tissue damage across treatment groups. (E) Western blot analysis of key serotonin pathway proteins in colon tissue: Tph1, 5-HT3R, 5-HT4R, SERT, TGR5, and TRPA1. (F) ELISA measurements of 5-HT and cAMP levels, and qPCR analysis of mRNA expression for Tph1, 5-HT3R, 5-HT4R, SERT, TGR5, and TRPA1 in colon tissue. Data were presented as mean ± SD or median (IQR). *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001. n=5/group. 5-HT, 5-hydroxytryptamine (serotonin); 5-HT3R, 5-HT receptor 3; 5-HT4R, 5-HT receptor 4; cAMP, cyclic adenosine monophosphate; CDCA, chenodeoxycholic acid; ELISA, enzyme-linked immunosorbent assay; GI, gastrointestinal; HE, hematoxylin and eosin; IQR, interquartile range; qPCR, quantitative polymerase chain reaction; SD, standard deviation; SERT, serotonin transporter; TGR5, Takeda G protein-coupled receptor 5; Tph1, tryptophan hydroxylase 1; TRPA1, transient receptor potential A1.

Article Snippet: LX1606 (T171759, Aladdin; listed in ) was used as a Tph1 inhibitor , while alosetron (A125218, Aladdin; listed in ) and GR113808 (HY-103152, Mce; listed in ) served as 5-HT3R and 5-HT4R antagonists, respectively ( , ).

Techniques: Expressing, Control, Staining, Western Blot, Enzyme-linked Immunosorbent Assay, Real-time Polymerase Chain Reaction, Standard Deviation

Journal: Translational Pediatrics

Article Title: Chenodeoxycholic acid activates the TGR5/TRPA1-5-HT pathway to regulate intestinal motility in breastfed infants and mouse models

doi: 10.21037/tp-2025-100

Figure Lengend Snippet: Impact of serotonin pathway inhibition on CDCA-induced changes in intestinal motility as described in . After CDCA treatment (20 mg/kg via enema for 7 days), mice received inhibitors targeting different components of the serotonin signaling pathway. (A) Representative images of GI transit distance after carmine red gavage (30 min) in mice treated with: Control (PBS), CDCA only, Alosetron (5-HT3R antagonist, 1 mg/kg, blocking serotonin receptor signaling), GR113808 (5-HT4R antagonist, 1 mg/kg, blocking a different serotonin receptor subtype), or LX1606 (Tph1 inhibitor, 200 mg/kg, blocking serotonin synthesis). The red arrow as in . (D) Similar transit images for mice treated with Control, CDCA only, SBI-115 (TGR5 antagonist, 15 mg/kg, blocking the bile acid receptor upstream of serotonin signaling), or HC-030031 (TRPA1 inhibitor, 150 mg/kg, blocking another upstream component in the signaling pathway). The red arrow as in . (B,E) Representative images of fecal appearance from corresponding treatment groups. (C,F) Quantitative measurements of fecal water content, GI transit time, colonic transit distance (60 min post-carmine), and ELISA results for 5-HT and cAMP levels in colon tissue for all treatment groups. The experimental design systematically targets different points in the TGR5/TRPA1-5-HT signaling axis as detailed in the Methods section (2.8 and 2.9). Data were presented as mean ± SD. *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001. n=5/group. 5-HT, 5-hydroxytryptamine (serotonin); 5-HT3R, 5-HT receptor 3; 5-HT4R, 5-HT receptor 4; cAMP, cyclic adenosine monophosphate; CDCA, chenodeoxycholic acid; ELISA, enzyme-linked immunosorbent assay; GI, gastrointestinal; PBS, phosphate-buffered saline; SD, standard deviation; Tph1, tryptophan hydroxylase 1; TRPA1, transient receptor potential A1.

Article Snippet: LX1606 (T171759, Aladdin; listed in ) was used as a Tph1 inhibitor , while alosetron (A125218, Aladdin; listed in ) and GR113808 (HY-103152, Mce; listed in ) served as 5-HT3R and 5-HT4R antagonists, respectively ( , ).

Techniques: Inhibition, Control, Blocking Assay, Enzyme-linked Immunosorbent Assay, Saline, Standard Deviation

Journal: Translational Pediatrics

Article Title: Chenodeoxycholic acid activates the TGR5/TRPA1-5-HT pathway to regulate intestinal motility in breastfed infants and mouse models

doi: 10.21037/tp-2025-100

Figure Lengend Snippet: Induction of serotonin pathway components in rat insulinoma-derived RIN-14B cells. These cells were used as an in vitro model of enterochromaffin cells to examine direct effects of CDCA treatment. (A) ELISA measurements of 5-HT secretion in response to 15 μM CDCA treatment, alongside cell proliferation assays showing no toxicity of CDCA at concentrations of 5–25 μM over 24–72 hours. (B) qPCR analysis of mRNA expression for Tph1, SERT, TGR5, and TRPA1 in RIN-14B cells following 15 μM CDCA treatment, demonstrating significant upregulation of these serotonin pathway components. Data were presented as mean ± SD. *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001. CDCA, chenodeoxycholic acid; ELISA, enzyme-linked immunosorbent assay; qPCR, quantitative polymerase chain reaction; SD, standard deviation; SERT, serotonin transporter; TGR5, Takeda G protein-coupled receptor 5; Tph1, tryptophan hydroxylase 1; TRPA1, transient receptor potential A1.

Article Snippet: LX1606 (T171759, Aladdin; listed in ) was used as a Tph1 inhibitor , while alosetron (A125218, Aladdin; listed in ) and GR113808 (HY-103152, Mce; listed in ) served as 5-HT3R and 5-HT4R antagonists, respectively ( , ).

Techniques: Derivative Assay, In Vitro, Enzyme-linked Immunosorbent Assay, Expressing, Real-time Polymerase Chain Reaction, Standard Deviation