F0127

A tailored reflection flow cell is used for probing aqueous solutions in-situ and measuring SEIRA spectra in reflection. The nanostructures are in an aqueous environment such as water or an aqueous sugar solution. All chemicals used were purchased from Sigma Aldrich. The sugar solutions were prepared by dissolving the desired amounts of glucose, fructose (F0127, Sigma Aldrich, Taufkirchen, Germany), galactose (G0750, Sigma Aldrich, Taufkirchen, Germany), lactose (61339, Sigma Aldrich, Taufkirchen, Germany), and maltose (M5885, Sigma Aldrich, Taufkirchen, Germany) in deionized water.

Tissue clearing was performed according to the SeeDB protocol^{49 (link)}. In brief, the fixed intestine was sequentially immersed in PBS containing 20, 40, 60, or 80% fructose (Sigma Cat# F0127) for 4 to 8 h at each step and with gentle rotation at room temperature. The tissue was then incubated in 100% fructose in water for 24 h at room temperature and embedded in the same solution. Screening, counting, and imaging of lineage tracing events were performed with a DeltaVision Elite microscopy system (GE Healthcare Life Sciences).

Animal studies were performed according to the Guide for the Care and Use of Laboratory Animals, published by the US National Institutes of Health (NIH publication No. 85–23, revised 1996) and approved by the Animal Experiments Inspectorate of the Danish Ministry of Justice. Four-week-old male Sprague–Dawley rats (Taconic, Ll. Skensved, Denmark) were randomly stratified into two groups. One group (controls) received unlimited normal chow (13 kcal % fat, Altromin 1319, Brogaarden, Lynge, Denmark) and water, and the other group, fructose-fat fed rats (FFFR), received unlimited high-fat diet (60 kcal % saturated fat, D12492, Research Diets, New Brunswick, USA) and 10 % fructose (F0127, Sigma-Aldrich, Brøndby, Denmark) in the drinking water as previously described [12 (link)]. To avoid bacterial growth in the drinking water, citric acid was added to give a pH of 3.6 in both control and fructose water. Rats were kept on this special diet for 6 weeks before entering the experiments described below.

Male C57BL/6 mice and SHP-KO mice (8–12 weeks old) were fasted for 4–12 h and injected via the tail vein with vehicle or FGF19 (1 mg kg⁻¹) at 9:00 a.m., and 2 h or 6 h later, livers were collected. For feeding experiments, mice were fasted for 12 h and then fed for 6 h and livers were collected for further analyses. For FXR activation studies, mice were fasted for 12 h and then treated intraperitoneally with GW4064 (30 mg kg⁻¹ in corn oil) for 6 h. For dietary obese mouse studies, mice were fed normal chow or a HFD (Harlan Teklad, TD88137) with 25% of fructose (Sigma, F0127) in water for 11 weeks. Since 1C cycle metabolism is influenced by the circadian rhythm^{25 (link)}, mouse experiments were done at similar times of the day. AhR-KO and TetRE-CA-AHR transgenic mice^{12 (link)} and SHP-KO^{21 (link)} and FGF15-KO^{52 (link)} mice have been described previously. For adenoviral experiments, mice were injected via the tail vein with 0.5–1.0 × 10⁹ active viral particles in 100 µl phosphate-buffered saline (PBS) and 2–3 weeks later, the mice were killed and livers were collected. Injection of these viral doses does not elicit marked inflammatory responses^{20 (link)}. All experiments were approved by the Institutional Animal Care and Use and Biosafety Committees of the University of Illinois at Urbana-Champaign.

A total of 27 C57BL/6J mice (male, 9 weeks old) were divided into three groups: (1) chow group (n = 9), which was administered with distilled water and standard chow; (2) HF group (n = 9), which was treated with a high-fructose diet [55% fructose (F0127, Sigma-Aldrich) + 45% sucrose (V900116, Sigma-Aldrich)] and 60% HF diet (D12492, Research Diets); and (3) DSS + HF group (n = 9), which was maintained on 1% DSS (MPbio.0216011080, MP Biomedicals), high-fructose diet (55% fructose + 45% sucrose), and 60% HF diet. DSS was administered in cycles, and each cycle consisted of 7 days of DSS administration followed by a 10-day interval with normal drinking water. The cycles were repeated throughout 19 weeks of experimentation.
The body weight of each mouse was monitored weekly throughout the period of experimentation. Stool, blood, liver, jejunum, ileum, and colon tissue samples were collected at week 19 and stored at −80°C until analysis.