Dendritic cell immunoreceptor 2 (DCIR2) deficiency decreases hepatic conventional dendritic cell content but not the progression of diet-induced obesity.

AIMS: Inflammatory pathways and immune system dysregulation participate in the onset and progression of cardiometabolic diseases. The dendritic cell immunoreceptor 2 (DCIR2) is a C-type lectin receptor mainly expressed by conventional type 2 dendritic cells, involved in antigen recognition and in the modulation of T cell response. Here, we investigated the effect of DCIR2 deficiency during the development of obesity. METHODS: DCIR2 KO mice and the WT counterpart were fed with high-fat diet (HFD) for 20 weeks. Weight gain, glucose and insulin tolerance were assessed, parallel to immune cell subset profiling and histological analysis. RESULTS: After HFD feeding, DCIR2 KO mice presented altered conventional dendritic cell distribution within the liver without affecting markers of hepatic inflammation. These observations were liver restricted, since immune profile of metabolic and lymphoid organs-namely adipose tissue, spleen and mesenteric lymph nodes-did not show differences between the two groups. This reflected in a similar metabolic profile of DCIR2 KO compared to WT mice, characterized by comparable body weight gain as well as adipose tissues, spleen, Peyer's patches and mesenteric lymph nodes weight at sacrifice. Also, insulin response was similar in both groups. CONCLUSION: Our data show that DCIR2 has a redundant role in the progression of diet-induced obesity and inflammation.

Dendritic cell marker Clec4a4 deficiency limits atherosclerosis progression.

Background and aims: Atherogenesis results from altered lipid metabolism and impaired immune response. Emerging evidence has suggested that dendritic cells (DCs) participate to atherosclerosis-related immune response, but their impact is scarcely characterized. Clec4a4 or DCIR2 (Dendritic cell immunoreceptor 2) is a C-type lectin receptor, mainly expressed by CD8α- DCs, able to modulate T cell immunity. However, whether this DC subset could play a role in the atherogenesis is still poorly understood. Thus, the aim of this study is to investigate whether the absence of Clec4a4 could affect atherosclerosis-related immune response and atherosclerosis itself. Methods: Dcir2 -/- Ldlr -/- and Ldlr -/- mice were fed a standard diet or cholesterol-enriched diet for 12 weeks. Subsequently, the profile of circulating and lymph nodes-resident immune cells was investigated together with the analysis of plasma lipid levels and atherosclerotic plaque extension in the aorta. Results: Here, we show that Clec4a4 expression is downregulated under hypercholesterolemia and its deficiency in Ldlr -/- mice results in the reduction of atherosclerotic plaque formation, together with altered lipid metabolism and impaired myeloid immune cell distribution. Conclusions: Our findings suggest a pro-atherosclerotic role of Clec4a4 in experimental atherosclerosis.

Crosstalk between dendritic cells and T lymphocytes during atherogenesis: Focus on antigen presentation and break of tolerance.

Atherosclerosis is a chronic disease resulting from an impaired lipid and immune homeostasis, where the interaction between innate and adaptive immune cells leads to the promotion of atherosclerosis-associated immune-inflammatory response. Emerging evidence has suggested that this response presents similarities to the reactivity of effector immune cells toward self-epitopes, often as a consequence of a break of tolerance. In this context, dendritic cells, a heterogeneous population of antigen presenting cells, play a key role in instructing effector T cells to react against foreign antigens and T regulatory cells to maintain tolerance against self-antigens and/or to patrol for self-reactive effector T cells. Alterations in this delicate balance appears to contribute to atherogenesis. The aim of this review is to discuss different DC subsets, and their role in atherosclerosis as well as in T cell polarization. Moreover, we will discuss how loss of T cell tolerogenic phenotype participates to the immune-inflammatory response associated to atherosclerosis and how a better understanding of these mechanisms might result in designing immunomodulatory therapies targeting DC-T cell crosstalk for the treatment of atherosclerosis-related inflammation.

Mannose Receptor Deficiency Impacts Bone Marrow and Circulating Immune Cells during High Fat Diet Induced Obesity.

The mannose receptor C-type 1 (Mrc1) is a C-type lectin receptor expressed on the immune cells and sinusoidal endothelial cells (ECs) of several tissues, including the bone marrow (BM). Parallel to systemic metabolic alterations and hematopoietic cell proliferation, high-fat diet (HFD) feeding increases the expression of Mrc1 in sinusoidal ECs, thus calling for the investigation of its role in bone marrow cell reprogramming and the metabolic profile during obesity. Mrc1-/- mice and wild-type (WT) littermates were fed an HFD (45% Kcal/diet) for 20 weeks. Weight gain was monitored during the diet regimen and glucose and insulin tolerance were assessed. Extensive flow cytometry profiling, histological, and proteomic analyses were performed. After HFD feeding, Mrc1-/- mice presented impaired medullary hematopoiesis with reduced myeloid progenitors and mature cells in parallel with an increase in BM adipocytes compared to controls. Accordingly, circulating levels of neutrophils and pro-inflammatory monocytes decreased in Mrc1-/- mice together with reduced infiltration of macrophages in the visceral adipose tissue and the liver compared to controls. Liver histological profiling coupled with untargeted proteomic analysis revealed that Mrc1-/- mice presented decreased liver steatosis and the downregulation of proteins belonging to pathways involved in liver dysfunction. This profile was reflected by improved glucose and insulin response and reduced weight gain during HFD feeding in Mrc1-/- mice compared to controls. Our data show that during HFD feeding, mannose receptor deficiency impacts BM and circulating immune cell subsets, which is associated with reduced systemic inflammation and resistance to obesity development.

[Family psychoeducational interventions for schizophrenia in routine settings: impact on patients' clinical status and social functioning and on relatives' burden and resources]. / Interventi psicoeducativi familiari per la schizofrenia nella pratica clinica: effetto sullo stato clinico e la disabilità dei pazienti e sul carico e le risorse familiari.

OBJECTIVE: This study explored the effectiveness of a psychoeducational family intervention for schizophrenia on patients' clinical status and disability and relatives' burden and perceived support. METHODS: The study has been carried out in 17 mental health centres. In each of them, 2 professionals were trained in a psychoeducational intervention and applied it for six months with families of users with schizophrenia. At baseline and six months later, patients' clinical status and disability, and relatives' burden, social network and professional support were assessed by validated tools. RESULTS: Of the seventy-one recruited families, 48 (68%) completed the intervention. At six months, a significant improvement was found in patients' clinical status and social functioning, as well as in relatives' burden and social and professional support. In particular, the percentage of patients with poor or very poor global social functioning dropped from 50% to 27% at six months. Forty percent of patients and 45% of relatives reported a significant improvement in their social contacts over the intervention period. CONCLUSIONS: The results of this study confirm the hypothesis that psychoeducational family interventions may have a significant effect on social outcome and family burden in schizophrenia when provided in routine conditions.

[Benefits and difficulties in implementing family psychoeducational interventions for schizophrenia in mental health services: results from a multicentre Italian study]. / Aspetti positivi e difficoltà nella diffusione degli interventi psicoeducativi familiari nella pratica clinica: uno studio multicentrico in 23 CSM italiani.

AIMS: This study aims to explore: a) the feasibility of psycho-educational interventions for families of users with schizophrenia in clinical practice by trained staff; b) the benefits and problems encountered by professionals in the use of these interventions. METHODS: 46 professionals from 23 Italian Mental Health Services (MHS) attended at a three-module training course in psycho-educational interventions and four supervisions in the subsequent year. Following the course, participants provided the intervention to families of users with schizophrenia. The difficulties and benefits encountered by trainees to use the intervention were registered on the Famnily Intervention Schedule. RESULTS: 83% of the participants completed the training course. Following the course, the intervention started in 71 families from 17 MHS. 76% of trainees provided the intervention to 2-5 families, while 13% of them only held informative sessions on schizophrenia. During the supervision period, the organisational difficulties experienced by the professionals were stable, while the benefits increased. Differences in benefits and difficulties were detected in relation to the trainees' experience and professional roles. CONCLUSIONS: It is possible to introduce psycho-educational interventions in MHS after a relatively brief period of training and supervision of the staff. Organisational difficulties need to be addressed to increase the dissemination of these interventions on a large scale.