Immune-non Immune Networks in Intestinal Inflammation

Abstract

The intestinal mucosa forms a primary barrier providing both barrier function and immediate effective recognition of bacterial products invading the mucosa. This is of great importance for the prevention of permanent and chronic inflammation as a reaction to the commensal intestinal flora and the multitude of antigens present in the intestinal lumen. It is obvious that a tight network of specialized cell types and intense cell-cell communication is required to maintain this function and coordinate immunological reactions. Yet most publications are focused on unidirectional cause and effect-chains. Since a real integrated view on the network of cellular functions is not available or at least incomplete bidirectional immune cell interactions with epithelial cells, fibroblasts/myofibroblasts, adipocytes endothelial cells and the nervous system are reviewed in this article. Networking is certainly mediated by different effector pathways but limited resources are available to assemble a model of interactions in intestinal inflammatory diseases. However, recent development of knowledge regarding unidirectional and bidirectional effect-chains is exciting. Apart from the classical discrimination of immune cells (such as neutrophils, macrophages, and cytotoxic T cells) and non immune cells (epithelial cells, fibroblasts, adipocytes and endothelial cells) it became stunningly evident that not only the classical immune cells have the ability to track down pathogens as most of the mentioned cell types express pathogen recognition receptors (toll-like receptors, Nod2) and defense mechanisms (such as secretion of defensin). Immune-non immune networks in intestinal inflammation

Mesenchymal Cells of the Intestinal Lamina Propria

“…Gabbiani and collaborators’ studies of wound healing and fibrosis, Kedinger’s research on intestinal development and morphogenesis, and Furuya & Furuya’s research on the anatomy and morphology of this interconnecting organelle and how it acts as a contractile network through dye-permeable gap junctions and endothelin/purinergic receptors have been particularly important contributions to myofibroblast biology (4–6). In the past decade, the myofibroblast’s role as a paracrine/autocrine mediator of inflammation has also become a productive area of investigation.…”

Use of Genetically Modified Bacteria to Modulate Adaptive Immunity

“…In contrast, commensal bacteria can antagonize TLR signaling as a way to promote immune tolerance to their constituents [43,44]. However, the molecular mechanisms responsible for commensal bacteria-induced suppression of PPR activation pathways are not well understood.…”

Oncostatin M induces RIG‐I and MDA5 expression and enhances the double‐stranded RNA response in fibroblasts

“…Fibroblasts are found in all tissues and referred to as sentinel cells of the connective tissue. Although fibroblasts are non‐professional immune cells, they play an important role in the innate and adaptive immunity, particularly in the early innate immune response due to their ability to produce high levels of IFN .…”