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Autoimmune diabetes arises spontaneously in Non-Obese Diabetic (NOD) mice, and the pathophysiology of this disease shares many similarities with human type 1 diabetes. Since its generation in 1980, the NOD mouse, derived from the Cataract Shinogi strain, has represented the gold standard of spontaneous disease models, allowing to investigate autoimmune diabetes disease progression and susceptibility traits, as well as to test a wide array of potential treatments and therapies. Beyond autoimmune diabetes, NOD mice also exhibit polyautoimmunity, presenting with a low incidence of autoimmune thyroiditis and Sjögren’s syndrome. Genetic manipulation of the NOD strain has led to the generation of new mouse models facilitating the study of these and other autoimmune pathologies. For instance, following deletion of specific genes or via insertion of resistance alleles at genetic loci, NOD mice can become fully resistant to autoimmune diabetes; yet the newly generated diabetes-resistant NOD strains often show a high incidence of other autoimmune diseases. This suggests that the NOD genetic background is highly autoimmune-prone and that genetic manipulations can shift the autoimmune response from the pancreas to other organs. Overall, multiple NOD variant strains have become invaluable tools for understanding the pathophysiology of and for dissecting the genetic susceptibility of organ-specific autoimmune diseases. An interesting commonality to all autoimmune diseases developing in variant strains of the NOD mice is the presence of autoantibodies. This review will present the NOD mouse as a model for studying autoimmune diseases beyond autoimmune diabetes.

The presence of an immature tumor vascular network contributes to cancer dissemination and the development of resistance to therapies. Strategies to normalize the tumor vasculature are therefore of significant therapeutic interest for cancer treatments. VEGF inhibitors are used clinically to normalize tumor blood vessels. However, the time frame and dosage of these inhibitors required to achieve normalization is rather narrow, and there is a need to identify additional signaling targets to attain vascular normalization. In addition to VEGF, the endothelial-specific receptor Alk1 plays a critical role in vascular development and promotes vascular remodeling and maturation. Therefore, we sought to evaluate the effects of the Alk1 ligand BMP9 on tumor vascular formation. BMP9 overexpression in Lewis Lung Carcinoma (LLC) tumors significantly delayed tumor growth. Blood vessels in BMP9-overexpressing LLC tumors displayed markers of vascular maturation and were characterized by increased perivascular cell coverage. Tumor vasculature normalization was associated with decreased permeability and increased perfusion. These changes in vascular function in BMP9-overexpressing LLC tumors resulted in significant alterations of the tumor microenvironment, characterized by a decrease in hypoxia and an increase in immune infiltration. In conclusion, we show that BMP9 promotes vascular normalization in LLC tumors that leads to changes in the microenvironment.

In response to microbial stimulation, monocytes can differentiate into macrophages or monocyte-derived dendritic cells (MoDCs) but the molecular requirements guiding these possible fates are poorly understood. In addition, the physiological importance of MoDCs in the host cellular and immune responses to microbes remains elusive. Here, we demonstrate that the nuclear orphan receptor NR4A3 is required for the proper differentiation of MoDCs but not for other types of DCs. Indeed, the generation of DC-SIGN⁺ MoDCs in response to LPS was severely impaired in Nr4a3−/− mice, which resulted in the inability to mount optimal CD8⁺ T cell responses to gram-negative bacteria. Transcriptomic analyses revealed that NR4A3 is required to skew monocyte differentiation toward MoDCs, at the expense of macrophages, and allows the acquisition of migratory characteristics required for MoDC function. Altogether, our data identify that the NR4A3 transcription factor is required to guide the fate of monocytes toward MoDCs.

Receptor-interacting protein kinase 3 (RIPK3) is a protein involved in cell death and inflammatory processes. The most recognized function of RIPK3 is the induction of necroptosis, an inflammatory type of cell death that is dependent on RIPK3 kinase activity. Deficiency in RIPK3-dependent pathways has been associated with protection from various inflammatory and autoimmune conditions. Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the generation of autoantibodies to multiple intracellular antigens leading to multi-organ pathology. Little is known about the involvement of RIPK3-dependent pathways in SLE. We have previously shown that autoantibody generation in an induced model of murine lupus is impaired in RIPK3-deficient mice. The current study aimed to identify the RIPK3-dependent mechanisms that contribute to autoantibody generation in this induced model of murine lupus. SLE was induced in C57BL/6 (wild type), RIPK3 , RIPK , and MLKL mice by subcutaneous immunization with a mixture of β2-glycoprotein I and lipopolysaccharide in order to evaluate the contribution of RIPK3 and MLKL to autoantibody production in this model. Bone marrow chimeras were generated to investigate the impact of RIPK3 deficiency within the hematopoietic compartment. Antigen presentation assays assessed the impact of RIPK3 deficiency in antigen presenting cells on T cell activation . T cells were evaluated by flow cytometry following the induction of SLE in wild type and RIPK3-dependent pathway-deficient mice. Generation of autoantibodies to SLE antigens following immunization with β2-glycoprotein I and lipopolysaccharide was found to be dependent on RIPK3 activity, but independent of MLKL (i.e., RIPK3-dependent necroptosis). Bone marrow chimeric experiments revealed that RIPK3 mediates autoantibody generation through both immune and non-immune compartments. RIPK3 deficiency within antigen presenting cells did not impact T cell activation in vitro. Moreover, early and late T cell activation ex vivo was not impaired in RIPK3-deficient mice following induction of murine lupus. These results suggest that RIPK3 contributes to autoantibody generation in our induced model of murine lupus through an interplay of pathways that appear to be independent of necroptosis and antigen presentation.

Dendritic cells (DCs) patrol the organism at an immature stage to detect the presence of pathogens. Once activated, these mature DCs reach the lymph nodes to activate antigen-specific T lymphocytes and thus initiate an adaptative immune response to control the pathogen. The migration of both immature and mature DCs is a key process for their optimal function. DC migration requires transit through narrow constrictions that is allowed by their high local and global deformation capabilities. In addition to cytoplasmic changes, the nucleus mechanical properties also have a major impact for cellular migration and motility. Yet, nucleus intracellular mobility of dendritic cells or its variation upon maturation have not been investigated. Our study defines the biophysical phenotypic variations of dendritic cells upon maturation using interferometric deformability cytometry. This method characterizes different cellular mechanical properties, such as elongation and nucleus offset, by assessing the refractive index spatial distribution of shear-induced deformed cells. By using these parameters, our data suggest that in vitro bone marrow derived dendritic cell (BMDC) maturation induces cell stiffening and reduces nucleus mobility, allowing to distinguish immature and mature dendritic cells. Overall, our method provides insights on intracellular mechanical properties of two dendritic cell states.

Interleukin-17 receptor D (IL-17RD), also known as similar expression to Fgf genes (SEF), is proposed to act as a signaling hub that negatively regulates mitogenic signaling pathways, like the ERK1/2 MAP kinase pathway, and innate immune signaling. The expression of IL-17RD is downregulated in certain solid tumors, which has led to the hypothesis that it may exert tumor suppressor functions. However, the role of IL-17RD in tumor biology remains to be studied in vivo. Here, we show that genetic disruption of Il17rd leads to the increased formation of spontaneous tumors in multiple tissues of aging mice. Loss of IL-17RD also promotes tumor development in a model of colitis-associated colorectal cancer, associated with an exacerbated inflammatory response. Colon tumors from IL-17RD-deficient mice are characterized by a strong enrichment in inflammation-related gene signatures, elevated expression of pro-inflammatory tumorigenic cytokines, such as IL-17A and IL-6, and increased STAT3 tyrosine phosphorylation. We further show that RNAi depletion of IL-17RD enhances Toll-like receptor and IL-17A signaling in colon adenocarcinoma cells. No change in the proliferation of normal or tumor intestinal epithelial cells was observed upon genetic inactivation of IL-17RD. Our findings establish IL-17RD as a tumor suppressor in mice and suggest that the protein exerts its function mainly by limiting the extent and duration of inflammation.

Cardiotrophin-like cytokine factor 1 (CLCF1) is a cytokine of the IL6/IL12 superfamily with pro-neurotrophic and immune-modulating functions. Although the pro-neurotrophic activities of CLCF1 are mediated through the ciliary neurotrophic factor receptor (CNTFR), the α receptor chain of the CNTFR, CNTFRα, is not expressed by immune cells. This suggests the presence of an alternative receptor or protein complex that mediates the immune activities of CLCF1. Using the BioID2 proximity-dependent biotinylation assay, we identified p40, the β subunit of IL12/IL23, as a potential interaction partner for CLCF1. We confirmed the protein-protein interaction between CLCF1 and p40 using co-immunoprecipitation and a proximity ligation assay. We also observed that the CLCF1-p40 complex forms both intracellularly and in the extracellular space. Furthermore, secretion of the CLCF1-p40 heterodimer was induced by the cytokine receptor-like factor 1 (CRLF1), leading to the release of a tripartite CLCF1-CRLF1-p40 complex. Lastly, we showed that a CLCF1-p40 fusion protein binds to both CNTFRα and IL12Rβ1. Taken together, our results uncover a new putative composite cytokine of the IL6/IL12 superfamily, which might affect our understanding of both CLCF1 activities and p40-associated pathologies. Moreover, our results reinforce the connection between the IL6 and IL12 cytokine families, and suggest that other possible protein interactions between these two families should be further investigated.

Adrian Liston and colleagues use a transgenic mouse model to demonstrate that beta cell failure is a mechanistic commonality in type 1 and type 2 diabetes. They find that the changes in the molecular pathways identified as contributing to beta cell loss are paralleled in human islets from patients with type 2 diabetes. Type 1 (T1D) and type 2 (T2D) diabetes share pathophysiological characteristics, yet mechanistic links have remained elusive. T1D results from autoimmune destruction of pancreatic beta cells, whereas beta cell failure in T2D is delayed and progressive. Here we find a new genetic component of diabetes susceptibility in T1D non-obese diabetic (NOD) mice, identifying immune-independent beta cell fragility. Genetic variation in Xrcc4 and Glis3 alters the response of NOD beta cells to unfolded protein stress, enhancing the apoptotic and senescent fates. The same transcriptional relationships were observed in human islets, demonstrating the role of beta cell fragility in genetic predisposition to diabetes.

Cardiotrophin-like cytokine factor 1 (CLCF1) is an IL-6 family cytokine with neurotrophic and immuno-modulating functions. CLCF1 mRNA has been detected in primary and secondary lymphoid organs, and up-regulation of CLCF1 mRNA levels has been associated with the T helper (Th) 17 polarization. However, information regarding CLCF1 expression by immune cells at the protein level remains scarce. We have developed a methodology that uses a monoclonal antibody (mAb) directed against CLCF1 for the detection of human and mouse CLCF1 by flow cytometry. We have successfully detected CLCF1 protein expression in cells from the mouse pro-B cell line Ba/F3 that were transduced with CLCF1 cDNA. Interestingly, we found that the anti-CLCF1 mAb inhibits CLCF1 biological activity in vitro by binding to an epitope that encompasses site III of the cytokine. Moreover, we have detected CLCF1 expression in mouse splenic T cells, as well as in vitro differentiated Th1 cells. The specificity of the fluorescence signal was demonstrated using Clcf1 -deficient lymphocytes generated using a conditional knock-out mouse model. The detection of CLCF1 protein by flow cytometry will be a valuable tool to study CLCF1 expression during normal and pathological immune responses.

Corneal HSV-1 infections are a leading cause of infectious blindness globally by triggering tissue damage due to the intense inflammation. HSV-1 infections are treated mainly with antiviral drugs that clear the infections but are inefficient as prophylactics. The body produces innate cationic host defence peptides (cHDP), such as the cathelicidin LL37. Various epithelia, including the corneal epithelium, express LL37. cHDPs can cause disintegration of pathogen membranes, stimulate chemokine production, and attract immune cells. Here, we selected GF17, a peptide containing the LL37 fragment with bioactivity but with minimal cytotoxicity, and added two cell-penetrating amino acids to enhance its activity. The resulting GF19 was relatively cell-friendly, inducing only partial activation of antigen presenting immune cells in vitro. We showed that HSV-1 spreads by tunneling nanotubes in cultured human corneal epithelial cells. GF19 given before infection was able to block infection, most likely by blocking viral entry. When cells were sequentially  exposed to viruses and GF19,  the infection was attenuated but not arrested, supporting the contention that the GF19 mode of action was to block viral entry. Encapsulation into silica nanoparticles allowed a more sustained release of GF19, enhancing its activity. GF19 is most likely suitable as a prevention rather than a virucidal treatment.