Humanized NSG Mouse Models as a Preclinical Tool for Translational Research in Inflammatory Bowel Diseases

Preclinical proof of principle for orally delivered Th17 antagonist miniproteins

Interleukin (IL)-23 and IL-17 are well-validated therapeutic targets in autoinflammatory diseases. Antibodies targeting IL-23 and IL-17 have shown clinical efficacy but are limited by high costs, safety risks, lack of sustained efficacy, and poor patient convenience as they require parenteral administration. Here, we present designed miniproteins inhibiting IL-23R and IL-17 with antibody-like, low picomolar affinities at a fraction of the molecular size. The minibinders potently block cell signaling in vitro and are extremely stable, enabling oral administration and low-cost manufacturing. The orally administered IL-23R minibinder shows efficacy better than a clinical anti-IL-23 antibody in mouse colitis and has a favorable pharmacokinetics (PK) and biodistribution profile in rats. This work demonstrates that orally administered de novo-designed minibinders can reach a therapeutic target past the gut epithelial barrier. With high potency, gut stability, and straightforward manufacturability, de novo-designed minibinders are a promising modality for oral biologics.

NOD/Scid IL2Rγnull Mice Reconstituted with PBMCs from Patients with Atopic Dermatitis or Psoriasis Vulgaris Reflect the Respective Phenotype

NSG (NOD/Scid IL2Rγnull) mice reconstituted with PBMCs donated by patients with ulcerative colitis or Crohn's disease highly reflect the respective pathological phenotype. To determine whether these findings could be applicable to atopic dermatitis (AD) and psoriasis vulgaris (PV), PBMCs isolated from patients with AD and PV were first subjected to immunological profiling. Subsequently, NSG mice were reconstituted with these PBMCs. Hierarchical clustering and network analysis revealed a distinct profile of patients with AD and PV with activated CD4+ T cells (CD69, CD25) occupying a central position in the AD network and CD4+ CD134+ cells acting as the main hub in the PV network. After dermal application of DMSO, both NSG mice reconstituted with PBMCs from donors with AD (ie, NSG-AD mice) and NSG mice reconstituted with PBMCs from donors with PV (ie, NSG-PV mice) exhibited increased clinical, skin, and histological scores. Immunohistochemical analysis, frequencies of splenic human leukocytes, and cytokine expression levels indicated that CD4+ CD69+ cells, M1 and TSLP receptor-expressing monocytes, switched B cells, and monocyte chemoattractant protein 3 were the driving factors of inflammation in NSG-AD mice. In contrast, inflammation in NSG-PV mice was characterized by an increase in fibroblasts in the epidermis, frequencies of CD1a-expressing monocytes, and IL-17 levels. Therefore, the pathological phenotypes of NSG-AD mice and NSG-PV mice differ and partially reflect the respective human diseases.

Recent advances in intestinal fibrosis

Despite many progresses have been made in the treatment of inflammatory bowel disease, especially due to the increasing number of effective therapies, the development of tissue fibrosis is a very common occurrence along the natural history of this condition. To a certain extent, fibrogenesis is a physiological and necessary process in all those conditions characterised by chronic inflammation. However, the excessive deposition of extracellular matrix within the bowel wall will end up in the formation of strictures, with the consequent need for surgery. A number of mechanisms have been described in this process, but some of them are not yet clear. For sure, the main trigger is the presence of a persistent inflammatory status within the mucosa, which in turn favours the occurrence of a pro-fibrogenic environment. Among the main key players, myofibroblasts, fibroblasts, immune cells, growth factors and cytokines must be mentioned. Although there are no available therapies able to target fibrosis, the only way to prevent it is by controlling inflammation. In this review, we summarize the state of art of the mechanisms involved in gut fibrogenesis, how to diagnose it, and which potential targets could be druggable to tackle fibrosis.