ECM signaling regulates collective cellular dynamics to control pancreas branching morphogenesis

During pancreas development, epithelial buds undergo branching morphogenesis to form an exocrine and endocrine gland. Proper morphogenesis is necessary for correct lineage allocation of pancreatic progenitors; however, the cellular events underlying pancreas morphogenesis are unknown. Here, we employed time-lapse microscopy and fluorescent labeling of cells to analyze cell behaviors associated with pancreas morphogenesis. We observed that outer bud cells adjacent to the basement membrane are pleomorphic and rearrange frequently; additionally, they largely remain in the outer cell compartment even after mitosis. These cell behaviors and pancreas branching depend on cell contacts with the basement membrane, which induce actomyosin cytoskeleton remodeling via integrin-mediated activation of FAK/Src signaling. We show that integrin signaling reduces E-cadherin-mediated cell-cell adhesion in outer cells and provide genetic evidence that this regulation is necessary for initiation of branching. Our study suggests that regulation of cell motility and adhesion by local niche cues initiates pancreas branching morphogenesis

Blood cholesterol and lipid-lowering effects of carrageenan on human volunteers

Algal polysaccharides such as carrageenan are good sources of dietary fibre. Previous studies have shown that carrageenan has hypoglycemic effects, but its cholesterol and lipid-lowering effects have yet to be demonstrated. In this study, carrageenan was incorporated into 4 food items, then fed to 20 human volunteers to determine its effects on blood cholesterol and lipid levels. The study followed a randomized crossover design. Each phase of the study -control and experimental -lasted for 8 weeks separated by a 2-week washout. At control, the subjects consumed their usual food intake; at experimental, they were given test foods with carrageenan partly substituting similar items in their usual diet. Fasting venous blood samples were collected immediately before and after each phase to assay serum cholesterol and triglyceride. The mean serum cholesterol was significantly lower (P < 0.0014) after the experimental phase at 3.64 mmol/L compared with the mean level after the control phase, 5.44 mmol/L. The mean triglyceride level after the experimental phase, 0.87 mmol/L, was significantly lower (P < 0.0006) in comparison to the level after the control phase, 1.28 mmol/L. The mean HDL cholesterol level significantly increased (P < 0.0071) after the experimental phase at 1.65 mmol/L compared to the mean value after the control phase, 1.25 mmol/L. No significant differences were observed between the LDL cholesterol levels after the experimental and the control phases. This study indicates that regular inclusion of carrageenan in the diet may result in reduced blood cholesterol and lipid levels in human subjects

Antioxidant and cytotoxic activities of sulfated polysaccharides from five different edible seaweeds

In recent times, there has been a growing interest in the exploration of antioxidants and global trend toward the usage of seaweeds in the food industries. The low molecular weight up to 14 kDa sulfated polysaccharides of seaweeds (Portieria hornemannii, Spyridia hypnoides, Asparagopsis taxiformis, Centroceras clavulatum and Padina pavonica) were evaluated for in vitro antioxidant activities and cytotoxic assay using HeLa cell line and also characterized by FTIR. The high yield (7.74% alga dry wt.) of sulfated polysaccharide was observed in P. hornemannii followed by S. hypnoides (0.69%), C. clavulaum (0.55%) and A. taxiformis (0.17%). In the brown seaweed P. pavonica, the sulfated polysaccharide yield was 2.07%. High amount of sulfate was recorded in the polysaccharide of A. taxiformis followed by C. clavulaum, P. pavonica, S. hypnoides and P. hornemannii as indicative for bioactivity. The FTIR spectroscopic analysis supports the sulfated polysaccharides of S. hypnoides, C. clavulatum and A. taxiformis are similar to agar polymer whereas the spectral characteristics of P. hornemannii have similarities to carrageenan. The higher DPPH activity and reducing power were recorded in the polysaccharide of brown seaweed P. pavonica than the red seaweeds as follows: DPPH activities: S. hypnoides > A. taxiformis > C. clavulatum > P. hornimanii; Reducing power: A. taxiformis > P. hornimanii > S. hypnoides > C. clavulatum. The polysaccharide fractions contain up to 14 kDa from red seaweeds P. hornemannii and S. hypnoides followed by brown seaweed P. pavonica exhibit cytotoxic activity in HeLa cancer cell line (and are similar to structural properties of carrageenan extracted from P. hornemannii). The low molecular weight agar like polymer of S. hypnoides and alginate like brown seaweed P. pavonica showing better in vitro antioxidant activities that are capable of exhibiting cytotoxicity against HeLa cell line can be taken up further in-depth investigation for nutraceutical study.University of Algarve: DL 57/2016info:eu-repo/semantics/publishedVersio