Goblet cell LRRC26 regulates BK channel activation and protects against colitis in mice.

Goblet cells (GCs) are specialized cells of the intestinal epithelium contributing critically to mucosal homeostasis. One of the functions of GCs is to produce and secrete MUC2, the mucin that forms the scaffold of the intestinal mucus layer coating the epithelium and separates the luminal pathogens and commensal microbiota from the host tissues. Although a variety of ion channels and transporters are thought to impact on MUC2 secretion, the specific cellular mechanisms that regulate GC function remain incompletely understood. Previously, we demonstrated that leucine-rich repeat-containing protein 26 (LRRC26), a known regulatory subunit of the Ca2+-and voltage-activated K+ channel (BK channel), localizes specifically to secretory cells within the intestinal tract. Here, utilizing a mouse model in which MUC2 is fluorescently tagged, thereby allowing visualization of single GCs in intact colonic crypts, we show that murine colonic GCs have functional LRRC26-associated BK channels. In the absence of LRRC26, BK channels are present in GCs, but are not activated at physiological conditions. In contrast, all tested MUC2- cells completely lacked BK channels. Moreover, LRRC26-associated BK channels underlie the BK channel contribution to the resting transepithelial current across mouse distal colonic mucosa. Genetic ablation of either LRRC26 or BK pore-forming α-subunit in mice results in a dramatically enhanced susceptibility to colitis induced by dextran sodium sulfate. These results demonstrate that normal potassium flux through LRRC26-associated BK channels in GCs has protective effects against colitis in mice.

Evaluation of In vitro Anti-Cancer Activity of Methanolic Leaf Extract of Phoenix pusilla on Colon Cancer Cell Line.

Background: Cancer rates continue to climb, owing largely to the world population's aging and growth, as well as economically developing countries, a surge in cancer-causing behavior, particularly smoking. The third or fourth most prevalent type of cancer is colon cancer. Cancer of the large intestine (colon) is one of the primary causes of death from cancer. Colorectal cancer prevention is mostly based on adenomatous disease screening approaches. The cytotoxic and pharmacological properties of Phoenix pusilla are widely documented. As a result, there is little recorded evidence of its cytotoxic activity against colon cancer cells. Therefore, we planned to study the efficacy of a methanolic leaf extract of Phoenix pusilla against in vitro colon cancer cells. Aim: To evaluate the anti-cancer effects of the methanolic leaf extract of Phoenix pusilla on colon cancer cell lines. Materials and Methods: In vitro screening and anti-cancer effects of the methanolic effect of Phoenix pusilla on colon cancer cell lines were assessed by cell viability assays and cell and nuclear morphological studies. For the in vitro cell culture study, different concentrations of Phoenix pusilla leaf extract (0, 25, 50, 75, 100, 150 µg/ml) were used, and IC50 doses were calculated. Results: The results of the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay revealed that the fraction of viability cells significantly decreased in treated cells when compared to untreated control groups, was expressed as 100%, and an inhibitory concentration of µg/ml was identified. A phase-contrast microscope was used to observe cell shrinkage and cytoplasmic membrane blebbing. A fluorescent microscope was used to examine the apoptotic nuclei (internally dyed nuclei, shattered nuclei, and condensed chromatin). Conclusion: In conclusion, the present study results showed that the leaf extracts of Phoenix pusilla had a strong cytotoxic effect and induced significant apoptosis in the colon cancer cell lines at a concentration of 75 µg/ml in the 24 h incubation period. More research is needed to investigate the extract's active components as well as the molecular mechanisms underlying its anti-cancer properties.

A comparative study on the chemo-enzymatic upgrading of renewable biomass to 5-Hydroxymethylfurfural.

5-hydroxymethylfurfural (HMF) obtained from renewable biomass-derived carbohydrates is a potential sustainable substitute to petroleum-based building blocks. In the present work, we constituted a comparative study on the production of HMF from two widely available real biomasses in India- Agave americana and Casuarina equisetifolia. In the initial hydrolysis studies for the production of reducing sugars, 649.5 mg/g of fructose was obtained from the hydrolysis of 5% (w/v) A. americana biomass by the enzyme inulinase in 3 h at 50°C. Similarly, upon hydrolysis of 15% (w/v) C. equisetifolia biomass by the lignocellulolytic enzymes (laccase, cellulase and xylanase) from Trichoderma atroviride, 456.65 mg/g of reducing sugars was released in 24 h at 30°C. Subsequently, the dehydration of the obtained reducing sugars to HMF was achieved with titanium dioxide as the catalyst. The dehydration of A. americana-derived fructose at 140°C led to a maximum HMF yield of 92.6% in 15 min with 10% catalyst load. Contrarily, upon optimizing the process parameters for dehydration of C. equisetifolia derived reducing sugars, the maximum HMF yield of 85.7% was obtained at 110°C in 25 min with a TiO2 concentration of 10%. This study reports for the first time the utilization of C. equisetifolia biomass for HMF production and thus, by utilizing these inexpensive, abundantly available and highly functionalized polysaccharides, a strategical approach can be developed for the production of fine chemicals, eliminating the need of fossil-based chemicals. Implications: The catalytic upgrading of lignocellulosic biomass into high-valued platform chemicals like 5-Hydroxymethylfurfural (HMF) implies an extremely significant challenge to the attempts of establishing a green economy. Casuarina equisetifolia and Agave americana represents a sustainable feedstock for the production of HMF through catalytic integration. The present work describes a two-step reaction process where the initial depolymerization step comprises of an enzymatic hydrolysis followed by a chemical-catalyst mediated dehydration process. The utilization of a biocatalytic approach followed by mild chemical catalyst eliminates the need of hazardous chemical conversion processes. Thus, the HMF produced via sustainable can bridge the gap between carbohydrate chemistry and petroleum-based industrial chemistry because of the wide range of chemical intermediates and end-products that can be derived from this compound.