Patients with type 2 diabetes (T2D) have disease-associated changes in B-cell function, but the role these changes play in disease pathogenesis is not well established. Data herein show B cells from obese mice produce a proinflammatory cytokine profile compared with B cells from lean mice. Complementary in vivo studies show that obese B cell-null mice have decreased systemic inflammation, inflammatory B-and T-cell cytokines, adipose tissue inflammation, and insulin resistance (IR) compared with obese WT mice. Reduced inflammation in obese/insulin resistant B cell-null mice associates with an increased percentage of anti-inflammatory regulatory T cells (Tregs). This increase contrasts with the sharply decreased percentage of Tregs in obese compared with lean WT mice and suggests that B cells may be critical regulators of T-cell functions previously shown to play important roles in IR. We demonstrate that B cells from T2D (but not non-T2D) subjects support proinflammatory T-cell function in obesity/T2D through contact-dependent mechanisms. In contrast, human monocytes increase proinflammatory T-cell cytokines in both T2D and non-T2D analyses. These data support the conclusion that B cells are critical regulators of inflammation in T2D due to their direct ability to promote proinflammatory T-cell function and secrete a proinflammatory cytokine profile. Thus, B cells are potential therapeutic targets for T2D.immunometabolism | lymphocytes M ultiple studies support the concept that inflammation strongly associates with insulin resistance (IR), which, in addition to loss of islet function, defines type 2 diabetes (T2D) (1). Work implicating B cells in IR/T2D is limited. We showed B cells from T2D subjects secrete a proinflammatory cytokine profile, including an extraordinary inability to secrete the potent anti-inflammatory cytokine IL-10 and an elevated production of proinflammatory IL-8 compared with B cells from non-T2D subjects (2). Given the importance of B-cell IL-10 in preventing numerous inflammatory diseases (3, 4) and the links between IL-8 and T2D (5, 6), these data suggest that altered B-cell cytokine production plays an important role in initiating or promoting IR/T2D. Published analyses further support a role for B cells in IR and include studies of B cell-null New Zealand Obese (NZO) mice, which, in contrast to B cell-sufficient NZOs, fail to develop IR in response to obesity (7). These findings have been recently reproduced in studies showing obese B cell-null or B cell-depleted mice have less inflammation and IR than obese WT mice (8). Interestingly, T-cell cytokine production is decreased in obese B cell-null mouse adipose tissue (AT) (8), which raises the possibility that, in addition to production of a proinflammatory cytokine profile, B cells may function in IR by regulating the T cell-mediated inflammation known to drive disease pathogenesis (9, 10). We identified a proinflammatory T-cell ratio [defined by increased Th17 cells plus decreased regulatory T cells (Tregs)] in T2D patients that mirror...

Cancer-associated fibroblasts (CAF) represent a functionally heterogeneous population of activated fibroblasts that constitutes a major component of tumor stroma. Although CAFs have been shown to promote tumor growth and mediate resistance to chemotherapy, the mechanisms by which they may contribute to immune suppression within the tumor microenvironment (TME) in lung squamous cell carcinoma (LSCC) remain largely unexplored. Here, we identified a positive correlation between CAF and monocytic myeloid cell abundances in 501 primary LSCCs by mining The Cancer Genome Atlas data sets. We further validated this finding in an independent cohort using imaging mass cytometry and found a significant spatial interaction between CAFs and monocytic myeloid cells in the TME. To delineate the interplay between CAFs and monocytic myeloid cells, we used chemotaxis assays to show that LSCC patient-derived CAFs promoted recruitment of CCR2 þ monocytes via CCL2, which could be reversed by CCR2 inhibition. Using a three-dimensional culture system, we found that CAFs polarized monocytes to adopt a myeloid-derived suppressor cell (MDSC) phenotype, characterized by robust suppression of autologous CD8 þ T-cell proliferation and IFNg production. We further demonstrated that inhibiting IDO1 and NADPH oxidases, NOX2 and NOX4, restored CD8 þ T-cell proliferation by reducing reactive oxygen species (ROS) generation in CAF-induced MDSCs. Taken together, our study highlights a pivotal role of CAFs in regulating monocyte recruitment and differentiation and demonstrated that CCR2 inhibition and ROS scavenging abrogate the CAF-MDSC axis, illuminating a potential therapeutic path to reversing the CAF-mediated immunosuppressive microenvironment.

This information is current as Lupus ErythematosusMouse Models of Systemic − / − RIIB γ Fc and

Interferon regulatory factor 5-deficient (IRF5 (-/-) ) mice have been used for many studies of IRF5 biology. A recent report identifies a mutation in dedicator of cytokinesis 2 (DOCK2) as being responsible for the abnormal B-cell development phenotype observed in the IRF5 (-/-) line. Both dedicator of cytokinesis 2 (DOCK2) and IRF5 play important roles in immune cell function, raising the issue of whether immune effects previously associated with IRF5 are due to IRF5 or DOCK2. Here, we defined the insertion end-point of the DOCK2 mutation and designed a novel PCR to detect the mutation in genomic DNA. We confirmed the association of the DOCK2 mutation and the abnormal B-cell phenotype in our IRF5 (-/-) line and also established another IRF5 (-/-) line without the DOCK2 mutation. These two lines were used to compare the role of IRF5 in dendritic cells (DCs) and B cells in the presence or absence of the DOCK2 mutation. IRF5 deficiency reduces IFN-α, IFN-β and IL-6 production by Toll-like receptor 9 (TLR9)- and TLR7-stimulated DCs and reduces TLR7- and TLR9-induced IL-6 production by B cells to a similar extent in the two lines. Importantly however, IRF5 (-/-) mice with the DOCK2 mutation have higher serum levels of IgG1 and lower levels of IgG2b, IgG2a/c and IgG3 than IRF5 (-/-) mice without the DOCK2 mutation, suggesting that the DOCK2 mutation confers additional Th2-type effects. Overall, these studies help clarify the function of IRF5 in B cells and DCs in the absence of the DOCK2 mutation. In addition, the PCR described will be useful for other investigators using the IRF5 (-/-) mouse line.