CD40 activation in human pancreatic islets and ductal cells

Abstract

Aims/hypothesis CD40 expression on non-haematopoietic cells is linked to inflammation. We previously reported that CD40 is expressed on isolated human and non-human primate islets and its activation results in secretion of IL-8, macrophage inflammatory protein 1-beta (MIP-1β) and monocyte chemoattractant protein-1 (MCP-1) through nuclear factor-κB and extracellularly regulated kinases 1/2 pathways. The objective of this study was to identify the pattern of gene expression, and to study viability and functionality affected by CD40-CD40 ligand (CD40L) interaction in human islets. Furthermore, we have studied the CD40-mediated cytokine/chemokine profile in pancreatic ductal cells, as they are always present in human islet transplant preparations and express CD40 constitutively. Methods CD40-CD40L gene expression modulation was studied by microarray on islet cells depleted of ductal cells. Selected genes were validated by quantitative RT-PCR. The cytokine profile in purified ductal cells was evaluated by Luminex technology, based on the use of fluorescent-coated beads, known as microspheres, and capable of multiplex detection of proteins from a single sample. Glucosestimulated insulin secretion and islet viability were assessed by perifusion and 7-aminoactinomycin D membrane exclusion, respectively. Results Statistical analysis of microarrays identified 30 genes exhibiting at least a 2.5-fold increase across all replicate arrays. The majority of them were related to oxidative stress/inflammation. Prominently upregulated were chemokine C-X-C motif ligand 1 (CXCL1), CXCL2and CXCL3 belonging to the CXC family of chemokines related to IL-8. CD40-mediated CXCL1 secretion was confirmed by ELISA. The viability or in vitro function was not affected by CD40 activation. In addition to previously reported IL-8, MIP-1β and MCP-1, CD40 stimulation in ductal cells produced IL-1β, IFN-γ, TNF-α, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. Conclusions/interpretation CD40 activation in islets and ductal cells produces cytokines/chemokines with a broadspectrum range of biological functions.

Immune Cell Crosstalk in Obesity: A Key Role for Costimulation?

“…Clinical studies have demonstrated that sCD40L plasma levels are increased in obese patients and positively correlate with BMI, waist circumference, fasting glucose, and leukocyte counts and that sCD40L levels decrease after bariatric surgery (58). CD40 ligation on adipocytes results in activation of classical proinflammatory signal transduction pathways, including extracellular signal-related kinase, p38, Jun NH 2 -terminal kinase, mitogen-activated protein kinase, and nuclear factor-kB (NF-kB), which results in the expression of cytokines and chemokines, including TNF, IL-6, and MCP-1, as well as the prothrombotic mediator plasminogen activator inhibitor 1 (57,59,60). These proinflammatory mediators subsequently activate endothelial cells and immune cells, which promote a generalized proinflammatory AT status.…”

Expression of the co-signaling molecules CD40-CD40L and their growth inhibitory effect on pancreatic cancer in vitro

“…Studies showed that CD40 was expressed in human pancreatic islets and ductal cells and it was up-regulated in pancreatic cancer (16)(17)(18). Because CD40 activation is able to reverse immune suppression and drive antitumor T cell responses (17), researchers have tried the agonist CD40 antibody to treat pancreatic carcinoma and suggested that CD40 held potential to be a treatment target similarly to that in the treatment of other cancer types (17).…”

CD40–CD40L: Linking pancreatic, adipose tissue and vascular inflammation in type 2 diabetes and its complications

“…5 The co-stimulatory molecule CD40 is expressed on both human and mouse pancreatic islet β-cells and pancreatic duct cells, but not on α-cells. 9 The expression of CD40 on pancreatic islet and ductal cells is increased upon exposure to pro-inflammatory cytokines, including TNF-α, IL-1β and interferon (IFN)-γ, all abundantly present in the diabetic pancreas. 8,9 Whereas membrane-bound CD40L is expressed on immune cells that infiltrate the diabetic pancreas, sCD40L is cleaved from the surface of activated platelets by the proteinase ADAM 10.…”

“…10 Although the biological effects of sCD40L-mediated signalling in T2DM remain largely unknown, binding of membrane-bound CD40L to CD40 on β-cells results in the activation of nuclear factor kappa B (NFκB), and subsequently induces the expression of cytokines, including IL-6, IL-8 and chemokines, such as monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory protein (MIP)-1β. 8,9 This further enhances pancreatic inflammation and impairs β-cell insulin release or production. Although in vitro experiments suggested that insulin metabolism is not affected by CD40L signalling, Poggi et al 22 recently demonstrated that obese CD40L −/− mice have preserved insulin sensitivity and low plasma insulin levels compared to obese CD40L +/+ mice.…”

“…[19][20][21] Experimental studies suggest that inhibition of CD40-CD40L may reduce the systemic inflammatory response responsible for the progression of T2DM and the development of CVD, as discussed below. 8,9,22 …”