Extracellular Vesicles Secreted by TDO2-Augmented Fibroblasts Regulate Pro-inflammatory Response in Macrophages

Abstract

Extracellular vesicles (EVs) are secreted lipid bilayer vesicles that mediate cell to cell communication and are effectors of cell therapy. Previous work has shown that canonical Wnt signaling is necessary for cell and EV therapeutic potency. Tryptophan 2,3-dioxygenase (TDO2) is a target gene of canonical Wnt signaling. Augmenting TDO2 in therapeutically inert fibroblasts endows their EVs with immunomodulatory capacity including attenuating inflammatory signaling in macrophages. Transcriptomic analysis showed that macrophages treated with EVs from fibroblasts overexpressing TDO2 had blunted inflammatory response compared to control fibroblast EVs. In vivo, EVs from TDO2-overexpressing fibroblasts preserved cardiac function. Taken together, these results describe the role of a major canonical Wnt-target gene (TDO2) in driving the therapeutic potency of cells and their EVs.

TDO2‐augmented fibroblasts secrete EVs enriched in immunomodulatory Y‐derived small RNA

“…TDO2‐CCM or CCM from and HDFs (HDF‐CCM) were prepared using ultrafiltration (100 kDa cutoff). The presence of EVs in these CCM samples was confirmed in previous work including the presence of conserved EV markers and absence of cellular contamination (Peck et al., 2021 ). We used a well‐established mouse model of acute myocardial infarction (AMI; Figure 1a ).…”

“…The work detailed here represents a continuation of this mechanistic elucidation. Building from previous findings that TDO2 is a major upregulated target of wnt/β-catenin, we demonstrate that augmenting TDO2 expression in dermal fibroblasts switches their phenotype from therapeutically inert to potently immunomodulatory (Peck et al, 2021). In an in vivo model of acute myocardial infarction, we confirmed that the secretome of TDO2-augmented EVs exerted therapeutic effects compared to the secretome of normal fibroblasts.…”

“…Augmenting skin fibroblasts (which have no therapeutic capacity) with TDO2 enhanced their therapeutic capacity (Ibrahim et al., 2019 ), suggesting an active role of TDO2 in wnt/β‐catenin therapeutic signalling in CDCs. Consistent with previous work, TDO2‐augmentation of fibroblasts endowed them and the EVs they secrete with potent immunomodulatory capacity of the macrophage response (Peck et al., 2021 ). Since cells exert their effect through the secretion of EVs, it became important to investigate the changes in EV cargo upon augmentation with TDO2.…”

“…Having previously observed the potent immunomodulatory effects of TDO2‐augmented fibroblasts in vivo (Peck et al., 2021 ), and the immunomodulatory effects of TDO2‐EVs in vitro (Peck et al., 2021 ), we further examined whether concentrated conditioned media (from TDO2‐CCM) could recapitulate the disease‐modifying bioactivity of the engineered fibroblasts. TDO2‐CCM or CCM from and HDFs (HDF‐CCM) were prepared using ultrafiltration (100 kDa cutoff).…”

Nanovesicular Mediation of the Gut–Brain Axis by Probiotics: Insights into Irritable Bowel Syndrome

“…Interestingly, among subjects with dysbiosis, TDO 2 is present in plasma nanovescicles, and its levels are higher after 60 days of Acronelle ® (Bromatech S.r.l., Milan, Italy) assumption (Figure 1). Very few studies to date have demonstrated the presence of TDO 2/IDO in EVs obtained from patients with dysbiosis or inflammatory diseases [57][58][59][60] and, to the best of our knowledge, changes of TDO 2 levels in plasmatic EVs before and after probiotics treatment have not been described previously. Our results indicate that by plasmatic EVs, the microbiota can drive signals to the brain by inducing the modulation of neurotransmitters and their receptors.…”