SOCS3 Regulates Dectin-2-Induced Inflammation in PBMCs of Diabetic Patients

Abstract

The C-type lectin receptors (CLRs) Dectin-1 and Dectin-2 are involved in several innate immune responses and are expressed mainly in dendritic cells, monocytes, and macrophages. Dectin-1 activation exacerbates obesity, inflammation, and insulin resistance/type 2 diabetes (T2D). However, the role of Dectin-2 is not clear in T2D. This study aims to evaluate the expression and function of Dectin-2 in peripheral blood mononuclear cells (PBMCs) isolated from diabetic patients and non-diabetic controls. Flow-cytometry and qRT-PCR were performed to evaluate the expression of Dectin-2 in different leukocyte subpopulations isolated from T2D patients (n = 10) and matched non-diabetic controls (n = 11). The functional activity of Dectin-2 was identified in PBMCs. CRP, IL-1β, and TNF-α concentrations were determined by ELISA. siRNA transfection and Western blotting were performed to assess p-Syk and p-NF-kB expression. siRNA transfection was performed to knock down the gene of interest. Our results show that Dectin-2 expression was the highest in monocytes compared with other leukocyte subpopulations. The expression of Dectin-2 was significantly increased in the monocytes of T2D patients compared with non-diabetic controls. Dectin-2 expression positively correlated with markers of glucose homeostasis, including HOMA-IR and HbA1c. The expression of inflammatory markers was elevated in the PBMCs of T2D patients. Interestingly, SOCS3, a negative regulator of inflammation, was expressed significantly lowlier in the PBMCs of T2D patients. Moreover, SOCS3 expression was negatively correlated with Dectin-2 expression level. The further analysis of inflammatory signaling pathways showed a persistent activation of the Dectin-2-Syk-NFkB pathway that was instigated by the diminished expression of SOCS3. Dectin-2 activation failed to induce SOCS3 expression and suppress subsequent inflammatory responses in the PBMCs of diabetic patients. siRNA-mediated knockdown of SOCS3 in PBMCs displayed a similar inflammatory phenotype to diabetic PBMCs when exposed to Dectin-2 ligands. Altogether, our findings suggest that elevated Dectin-2 and its relationship with SOCS3 could be involved in the abnormal immune response observed in T2D patients.

The Role of TLR2 in Exercise-Induced Immunomodulation in normal weight individuals

“…Data presented as mean ± SD. GraphPad Prism (version 6.05; San Diego, CA) and SPSS for Windows version 19.01 (IBM SPSS Inc., Armonk, NY) were used for statistical analysis. Multiple linear regression analysis was used to examine the relationship between monocyte surface marker expression and metabolic risk variables associated with longer periods of physical activity, adjusting for potential confounding factors.…”

“…To determine monocyte/macrophage lineages in the whole blood, ow cytometry analysis was conducted using freshly collected whole blood samples using the protocol previously published (19). Brie y, 1 mL of lysing buffer was added to 0.1 mL of a blood sample to eliminate erythrocytes and the remaining peripheral blood mononuclear cells (PBMCs) populations were incubated with uorochromeconjugated mouse anti-human monoclonal antibodies against CD14, and TLR2 as well as with isotypespeci c antibodies for respective controls.The gating strategy used in this study consisted of visualizing the cells on a forward scatter area FSC(A)/forward scatter height FSC (H) plot (Figure .1A).…”

The role of TLR2 in exercise-induced immunomodulation in normal weight individuals

“…To determine monocyte/macrophage lineages in the whole blood, flow cytometry analysis was conducted using freshly collected whole blood samples using the protocol previously published 24 . Briefly, 1 mL of lysing buffer was added to 0.1 mL of a blood sample to eliminate erythrocytes and the remaining peripheral blood mononuclear cells (PBMCs) populations were incubated with fluorochrome-conjugated mouse anti-human monoclonal antibodies against CD14, and TLR2 as well as with isotype-specific antibodies for respective controls.…”

Expression of Steroid Receptor RNA Activator 1 (SRA1) in the Adipose Tissue Is Associated with TLRs and IRFs in Diabesity

“…Briefly, 50 ng of cDNA was amplified using TaqMan Gene Expression Master Mix (Applied Biosystems, CA, USA) and gene-specific 20 X TaqMan gene expression assays including forward and reverse primers ( Supplementary Table S2 ), target-specific TaqMan 5′FAM-labeled and 3′NFQ-labeled MGB probe, using 7500 Fast Real-Time PCR System (Applied Biosystems, CA, USA) as described elsewhere [ 42 ]. Target gene expression relative to control (NW fat samples) was determined using comparative Ct method [ 47 ] and data were normalized to GAPDH gene expression as described [ 48 , 49 , 50 , 51 , 52 ].…”