New method for isolation of rat lamina propria macrophages in colonic tissue

Systemic blockade of P2X7 receptor protects against sepsis-induced intestinal barrier disruption

Sepsis, during which the intestinal epithelial barrier is frequently disrupted, remains a challenging and life-threatening problem in clinical practice. The P2X7 receptor (P2X7R) is a non-selective adenosine triphosphate-gated cation channel present in macrophages that is involved in inflammatory responses. However, little is known about the role of P2X7R in macrophages during sepsis-induced intestinal barrier disruption. In this study, mice were treated with the P2X7R antagonist A740003 or the agonist BzATP by intra-peritoneal injection after the induction of gut-origin sepsis. The survival rates, inflammatory responses, intestinal barrier integrity, macrophage marker expression, and ERK and NF-κB activities were evaluated. Intestinal macrophages were also isolated and studied after exposure to Brilliant Blue G or BzATP. We found that a systemic P2X7R blockade downregulated sepsis-induced inflammatory responses and attenuated intestinal barrier dysfunction based on the evidence that mice in the A740003-treated group exhibited alleviated pro-inflammatory cytokine synthesis, intestinal hyperpermeability, epithelial apoptosis rates and tight junction damage compared with the septic mice. These changes were partly mediated by the inhibition of M1 macrophages activation via ERK/NF-κB pathways. Our data presented herein show that a P2X7R blockade could be a potential therapeutic target for the treatment of sepsis-induced intestinal barrier dysfunction.

Colonic macrophage polarization in homeostasis, inflammation, and cancer

Our review focuses on the colonic macrophage, a monocyte-derived, tissue-resident macrophage, and the role it plays in health and disease, specifically in inflammatory conditions such as inflammatory bowel disease and cancer of the colon and rectum. We give special emphasis to macrophage polarization, or phenotype, in these different states. We focus on macrophages because they are one of the most numerous leukocytes in the colon, and because they normally contribute to homeostasis through an anti-inflammatory phenotype. However, in conditions such as inflammatory bowel disease, proinflammatory macrophages are increased in the colon and have been linked to disease severity and progression. In colorectal cancer, tumor cells may employ anti-inflammatory macrophages to promote tumor growth and dissemination, whereas proinflammatory macrophages may antagonize tumor growth. Given the key roles that this cell type plays in homeostasis, inflammation, and cancer, the colonic macrophage is an intriguing therapeutic target. As such, potential macrophage-targeting strategies are discussed.

An optimized protocol for isolating lymphoid stromal cells from the intestinal lamina propria

Mesenchymal stromal cells in lymphoid organs, also called lymphoid stromal cells (LSCs), play a pivotal role in immunity by forming specialized microenvironments that provide signals for leukocyte migration, positioning, and survival. Best characterized in lymphoid organs, LSCs are also abundant in the intestinal mucosa, which harbors a rich repertoire of immune cells. However, the lack of efficient procedures for isolation and purification of LSCs from the intestine has been a major limitation to their characterization. Here we report a new method to efficiently isolate, in addition to immune cells, viable lymphoid stromal cells and other stromal subsets from the intestinal lamina propria for subsequent phenotypic and functional analysis.