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T cells play a crucial role in atherosclerosis, with its infiltration preceding the formation of atheroma. However, how T‐cell infiltration is regulated in atherosclerosis remains largely unknown. Here, this work demonstrates that dipeptidyl peptidase‐4 (DPP4) is a novel regulator of T‐cell motility in atherosclerosis. Single‐cell ribonucleic acid (RNA) sequencing and flow cytometry show that CD4+ T cells in atherosclerotic patients display a marked increase of DPP4. Lack of DPP4 in hematopoietic cells or T cells reduces T‐cell infiltration and atherosclerotic plaque volume in atherosclerosis mouse models. Mechanistically, DPP4 deficiency reduces T‐cell motility by suppressing the expression of microtubule associated protein midline‐1 (Mid1) in T cells. Deletion of either DPP4 or Mid1 inhibits chemokine‐induced shape change and motility, while restitution of Mid1 in Dpp4−/− T cell largely restores its migratory ability. Thus, DPP4/Mid1, as a novel regulator of T‐cell motility, may be a potential inflammatory target in atherosclerosis. [ABSTRACT FROM AUTHOR]

Abstract T cells play a crucial role in atherosclerosis, with its infiltration preceding the formation of atheroma. However, how T‐cell infiltration is regulated in atherosclerosis remains largely unknown. Here, this work demonstrates that dipeptidyl peptidase‐4 (DPP4) is a novel regulator of T‐cell motility in atherosclerosis. Single‐cell ribonucleic acid (RNA) sequencing and flow cytometry show that CD4+ T cells in atherosclerotic patients display a marked increase of DPP4. Lack of DPP4 in hematopoietic cells or T cells reduces T‐cell infiltration and atherosclerotic plaque volume in atherosclerosis mouse models. Mechanistically, DPP4 deficiency reduces T‐cell motility by suppressing the expression of microtubule associated protein midline‐1 (Mid1) in T cells. Deletion of either DPP4 or Mid1 inhibits chemokine‐induced shape change and motility, while restitution of Mid1 in Dpp4−/− T cell largely restores its migratory ability. Thus, DPP4/Mid1, as a novel regulator of T‐cell motility, may be a potential inflammatory target in atherosclerosis.

Objectives: Eosinophilic oesophagitis (EoE) is characterised by oesophageal inflammation, fibrosis and dysfunction. Micro (mi)‐RNAs interfere with pro‐inflammatory and pro‐fibrotic transcriptional programs, and miR‐223 was upregulated in oesophageal mucosal biopsy specimens from EoE patients. The therapeutic potential of modulating miR‐223 expression in vivo has not been determined. We aimed to elucidate the relevance of oesophageal miR‐223 expression in an in vivo model of EoE by inhibiting miR‐223 tissue expression. Methods: The expression of miR‐223 and the validated miR‐223 target insulin‐like growth factor receptor 1 (IGF1R) protein was determined in our paediatric cohort of EoE patients. A murine model of Aspergillus fumigatus‐induced EoE was employed, and oesophagi were assessed for miR‐233, IGF1R, T lymphocyte type 2 (T2) cytokine expression and eosinophil infiltration. Mice were treated with antagomirs targeting miR‐223 or resveratrol targeting its upstream regulator Midline‐1(MID‐1). Results: There was an inverse relationship between an increased expression of miR‐223 and a decreased IGF1R protein concentration in biopsy specimens from EoE patients. TNF‐related apoptosis‐inducing ligand deficiency, MID‐1 inhibition and resveratrol treatment suppressed miR‐223 expression. Furthermore, inhibition of miR‐223 and treatment with resveratrol in the oesophagus resulted in an amelioration of EoE hallmark features including eosinophilic infiltration, oesophageal circumference and a reduction in T2 cytokine expression. Conclusion: miR‐223 has a key role in the perpetuation of EoE hallmark features downstream of TNF‐related apoptosis‐inducing ligand and MID‐1 in an experimental model. These studies highlight a potentially critical role of miRNA function in EoE aetiology. miR‐223 expression in the oesophagus may be therapeutically modulated by resveratrol, providing a potential new therapeutic option to be explored in EoE patients for this increasingly prevalent condition. [ABSTRACT FROM AUTHOR]

Background Eosinophilic esophagitis (EoE) is an inflammatory disorder of the esophagus defined by eosinophil infiltration and tissue remodeling with resulting symptoms of esophageal dysfunction. TNF-related apoptosis-inducing ligand (TRAIL) promotes inflammation through upregulation of the E3 ubiquitin-ligase midline-1 (MID1), which binds to and deactivates the catalytic subunit of protein phosphatase 2Ac, resulting in increased nuclear factor κB activation. Objective We sought to elucidate the role of TRAIL in EoE. Methods We used Aspergillus fumigatus to induce EoE in TRAIL-sufficient (wild-type) and TRAIL-deficient (TRAIL −/− ) mice and targeted MID1 in the esophagus with small interfering RNA. We also treated mice with recombinant thymic stromal lymphopoietin (TSLP) and TRAIL. Results TRAIL deficiency and MID1 silencing with small interfering RNA reduced esophageal eosinophil and mast cell numbers and protected against esophageal circumference enlargement, muscularis externa thickening, and collagen deposition. MID1 expression and nuclear factor κB activation were reduced in TRAIL −/− mice, whereas protein phosphatase 2Ac levels were increased compared with those seen in wild-type control mice. This was associated with reduced expression of CCL24, CCL11, CCL20, IL-5, IL-13, IL-25, TGFB, and TSLP. Treatment with TSLP reconstituted hallmark features of EoE in TRAIL −/− mice and recombinant TRAIL induced esophageal TSLP expression in vivo in the absence of allergen. Post hoc analysis of gene array data demonstrated significant upregulation of TRAIL and MID1 in a cohort of children with EoE compared with that seen in controls. Conclusion TRAIL regulates MID1 and TSLP, inflammation, fibrosis, smooth muscle hypertrophy, and expression of inflammatory effector chemokines and cytokines in experimental EoE. [ABSTRACT FROM AUTHOR]

Abstract: The B-box type 2 domain is a prominent feature of a large and growing family of RING, B-box, coiled-coil (RBCC) domain-containing proteins and is also present in more than 1500 additional proteins. Most proteins usually contain a single B-box2 domain, although some proteins contain tandem domains consisting of both type 1 and type 2 B-boxes, which actually share little sequence similarity. Recently, we determined the solution structure of B-box1 from MID1, a putative E3 ubiquitin ligase that is mutated in X-linked Opitz G/BBB syndrome, and showed that it adopted a ββα RING-like fold. Here, we report the tertiary structure of the B-box2 (CHC(D/C)C2H2) domain from MID1 using multidimensional NMR spectroscopy. This MID1 B-box2 domain consists of a short α-helix and a structured loop with two short anti-parallel β-strands and adopts a tertiary structure similar to the B-box1 and RING structures, even though there is minimal primary sequence similarity between these domains. By mutagenesis, ESI-FTICR and ICP mass spectrometry, we show that the B-box2 domain coordinates two zinc atoms with a ‘cross-brace’ pattern: one by Cys175, His178, Cys195 and Cys198 and the other by Cys187, Asp190, His204, and His207. Interestingly, this is the first case that an aspartic acid is involved in zinc atom coordination in a zinc-finger domain, although aspartic acid has been shown to coordinate non-catalytic zinc in matrix metalloproteinases. In addition, the finding of a Cys195Phe substitution identified in a patient with X-linked Opitz GBBB syndrome supports the importance of proper zinc coordination for the function of the MID1 B-box2 domain. Notably, however, our structure differs from the only other published B-box2 structure, that from XNF7, which was shown to coordinate one zinc atom. Finally, the similarity in tertiary structures of the B-box2, B-box1 and RING domains suggests these domains have evolved from a common ancestor. [Copyright &y& Elsevier]