Involvement of caspase-3 in stilbene derivatives induced apoptosis of human neutrophils in vitro

Resveratrol Delivery from Porous Poly(lactide- co-glycolide) Scaffolds Promotes an Anti-Inflammatory Environment within Visceral Adipose Tissue

As biomaterial therapies emerge to address adipose tissue dysfunction that underlies metabolic disease, the immune response to these systems must be established. As a potential therapy, we are investigating resveratrol delivery from porous poly(lactide- co-glycolide) scaffolds designed to integrate with adipose tissue. Resveratrol was selected for its ability to protect mice and primates from high fat diet and broad anti-inflammatory properties. Herein, we report fabrication of scaffolds with high resveratrol loading that are stable and active for up to one year. In vitro release profiles indicate that drug release is biphasic with a burst release over 3 days followed by a plateau. Surprisingly, we find that PLG scaffolds implanted into adipose tissue of mice promote an anti-inflammatory environment characterized by high arginase-1 and low TNF-α and IL-6 compared to naïve unmanipulated fat. Resveratrol delivery from the scaffold augments this anti-inflammatory environment by decreasing monocyte and lymphocyte numbers at the implant site and increasing expression of IL-10 and IL-13, cytokines that promote healthy adipose tissue. In terms of therapeutic applications, implant of scaffolds designed to release resveratrol into the visceral fat decreases MCP-1 expression in mice fed a high fat diet, a molecule that drives both local and systemic inflammation during obesity. Taken together, resveratrol delivery to adipose tissue using poly(lactide- co-glycolide) scaffolds is a promising therapeutic strategy for the treatment of adipose tissue inflammation that drives metabolic disease.

Pinosylvin exacerbates LPS-induced apoptosis via ALOX 15 upregulation in leukocytes

Pinosylvin is known to have anti-inflammatory activity in endothelial cells. In this study, we found that pinosylvin had a pro-apoptotic activity in lipopolysaccharide (LPS)-preconditioned leukocytes. This finding suggests that pinosylvin has an effect on the resolution of inflammation. To understand the detailed mechanism, we examined if pinosylvin enhances cyclooxygenase (COX) or lipoxygenase (LOX) activity in THP-1 and U937 cells. LOX activity was found to be markedly increased by pinosylvin, whereas COX activity was not altered. Furthermore, we found that pinosylvin enhanced both levels of ALOX 15 mRNA and protein, implying that LOX activity, elevated by pinosylvin, is attributed to upregulation of ALOX 15 expression. From this cell signaling study, pinosylvin appeared to promote phosphorylations of ERK and JNK. ERK or JNK inhibitors were found to attenuate ALOX 15 expression and LPS-induced apoptosis promoted by pinosylvin. In conclusion, pinosylvin enhances the apoptosis of LPS-preconditioned leukocytes by up-regulating ALOX 15 expression through ERK and JNK. These findings suggest that pinosylvin may induce the resolution of inflammation.

Therapeutic Potential and Molecular Targets of Piceatannol in Chronic Diseases

Piceatannol (3,3',4,5'-tetrahydroxy-trans-stilbene; PIC) is a naturally occurring stilbene present in diverse plant sources. PIC is a hydroxylated analog of resveratrol and produced from resveratrol by microsomal cytochrome P450 1A11/2 and 1B1 activities. Like resveratrol, PIC has a broad spectrum of health beneficial effects, many of which are attributable to its antioxidative and anti-inflammatory activities. PIC exerts anticarcinogenic effects by targeting specific proteins involved in regulating cancer cell proliferation, survival/death, invasion, metastasis, angiogenesis, etc. in tumor microenvironment. PIC also has other health promoting and disease preventing functions, such as anti-obese, antidiabetic, neuroptotective, cardioprotective, anti-allergic, anti-aging properties. This review outlines the principal biological activities of PIC and underlying mechanisms with special focus on intracellular signaling molecules/pathways involved.

Self-renewing Monolayer of Primary Colonic or Rectal Epithelial Cells

BACKGROUND & AIMS

Three-dimensional organoid culture has fundamentally changed the in vitro study of intestinal biology enabling novel assays; however, its use is limited because of an inaccessible luminal compartment and challenges to data gathering in a three-dimensional hydrogel matrix. Long-lived, self-renewing 2-dimensional (2-D) tissue cultured from primary colon cells has not been accomplished.

METHODS

The surface matrix and chemical factors that sustain 2-D mouse colonic and human rectal epithelial cell monolayers with cell repertoires comparable to that in vivo were identified.

RESULTS

The monolayers formed organoids or colonoids when placed in standard Matrigel culture. As with the colonoids, the monolayers exhibited compartmentalization of proliferative and differentiated cells, with proliferative cells located near the peripheral edges of growing monolayers and differentiated cells predominated in the central regions. Screening of 77 dietary compounds and metabolites revealed altered proliferation or differentiation of the murine colonic epithelium. When exposed to a subset of the compound library, murine organoids exhibited similar responses to that of the monolayer but with differences that were likely attributable to the inaccessible organoid lumen. The response of the human primary epithelium to a compound subset was distinct from that of both the murine primary epithelium and human tumor cells.

CONCLUSIONS

This study demonstrates that a self-renewing 2-D murine and human monolayer derived from primary cells can serve as a physiologically relevant assay system for study of stem cell renewal and differentiation and for compound screening. The platform holds transformative potential for personalized and precision medicine and can be applied to emerging areas of disease modeling and microbiome studies.

On the pharmacology of oxidative burst of human neutrophils

The effect of three therapeutically used drugs and five polyphenolic compounds on the mechanism of oxidative burst was compared in whole blood and isolated neutrophils at cellular and molecular level. In 10 microM concentration, the compounds investigated decreased the oxidative burst of whole blood in the rank order of potency: N-feruloylserotonin (N-f-5HT) > curcumin (CUR) > quercetin (QUER) > arbutin (ARB) > resveratrol (RES) > dithiaden (DIT) > carvedilol (CARV) > brompheniramine (BPA). The ratio between the percentage inhibition of extracellular versus intracellular chemiluminescence (CL) followed the rank order QUER > N-f-5HT > RES > CUR > DIT and is indicative of the positive effect of the compounds tested against oxidative burst of neutrophils, demonstrating suppression of reactive oxygen species extracellularly with minimal alteration of intracellular reactive oxygen species (ROS). Activation of protein kinase C was significantly decreased by DIT, CUR, QUER and N-f-5HT. CARV, DIT, QUER and ARB reduced activated neutrophil myeloperoxidase release more significantly compared with the effect on superoxide anion generation. All compounds tested increased the activity of caspase-3 in cell-free system. It is suggested that other regulatory mechanisms than protein kinase C might participate in the inhibition of neutrophil activation with the compounds tested. Different mechanisms are concerned in controlling the assembly of NADPH oxidase and the regulatory role of calcium ions is suggested. Compounds decreasing the amount of extracellular ROS generation, yet affecting but minimally intracellular ROS generation, are promising for further investigation in vivo.