Abstract P289: Effect of Abaptacept on Blood Pressure in Essential Hypertensive Subjects with Rheumatological Disorders

We previously showed that abatacept, an inhibitor of T cell co-stimulation, prevents and reverses experimental hypertension. We now investigated whether it lowers blood pressure (BP) in humans. Of 1624 subjects receiving this drug in our de-identified electronic health record, 320 had hypertension and adequate baseline and follow up data (1 month to 3 years). Use of glucocorticoids (GC), non-steroidal antiinflammatory agents (NSAIDs), and antihypertensive drugs (HTND) was scored with the WHO system. ΔBPs at 1, 3 and 6 months and 1, 2 and 3 years after abatacept were adjusted for concomitant changes in medications and weights (Wt) by multivariate regression. Subjects were 80.6% female, 88.4% white, age 62±1 y, BMI 30.9±0.4 Kg/m 2 and BP 128.2±0.8/74.6±0.5 mmHg. Significant changes in confounders over time included decreases in GC, NSAID and HTND over the initial months followed by rebound beyond baseline at 2 and 3 years, and increases in Wt in these late periods. Changes in adjusted BP were limited to an increase in systolic BP at 2 years (1.75±1.04, p<0.05) and a decrease in diastolic BP at 3 years (-1.67±0.80, p<0.02). 91 subjects (28.4%) had a decrease of MAP ≥5 mmHg in at least half of the periods. ΔBP in these “responders” vs all other subjects was -10.8±0.7/-7.6±0.4, MAP -8.6±0.4 vs +5.0±0.4/+2.3±0.2, MAP +3.2±0.2, but these groups did not differ in sex, age, race, obesity, use of concomitant immunomodulators, pressors or blockers of the renin-angiotensin system (RASB). However, pooled adjusted ΔBP differed between women and men (diastolic -0.72±0.26 vs +1.48±0.48, p=0.0002; MAP -0.29±0.26 vs +1.58±0.55, p=0.003); between subjects younger and older than 65 y (systolic -0.05±0.48 vs +1.88±0.58, p=0.021; MAP -0.39±0.33 vs +0.64±0.37, p=0.037); and between those with BMI≤25 and >25 Kg/m 2 (systolic -1.31±0.79 vs +1.37±0.42, p<0.008). Finally, Δsystolic BP was -0.15±0.53 in subjects not taking and +1.42±0.50 in those taking RASB, p=0.037. In summary, long term use of abatacept mildly reduces BP in lean women with essential hypertension and rheumatological disorders. The effect is attenuated by obesity and perhaps also by aging and treatment with RASB. Further studies of abatacept in resistant essential hypertension are warranted, particularly in women.

Abstract 022: Proteasome Inhibition Prevents Renal Inflammation and Hypertension by Abrogation of Dendritic Cell Autoantigen Presentation

Reactive oxygen species (ROS) have been shown to be important mediators of hypertension. Isolevuglandins (isoLG) are oxidation products of fatty acids that adduct to lysine residues of proteins. Our prior data suggest that isoLG-adducted proteins are presented by dendritic cells (DCs) and activate T-cells resulting in hypertension. Identification of the source and mechanism of presentation of isoLG adducts is critical for the development of therapies targeting this process. Antigens formed intracellularly are processed by the proteasome and presented to CD8 + T cells in MHC class I (MHC-I). We hypothesize that within DCs, isoLG-adducted peptides are processed by the proteasome and presented in MHC-I. Treatment of mouse DCs with the oxidant tert-butyl hydroperoxide (TBHP) increased levels of isoLG-adducts on the DC surface, as detected by flow cytometry, from 1.3 x 10 3 to 11.4 x 10 3 /10 6 DCs (N = 9, P < 0.01). Co-treatment of mouse DCs with TBHP and proteasome inhibitors (PIs) bortezomib (BTZ) or MG132 attenuated surface isoLG-adduct levels when compared to TBHP alone (2.7 x 10 3 or 3.5 x 10 3 vs 11.4 x 10 3 /10 6 DCs, N = 9, P < 0.001). Moreover, using flow cytometry-based fluorescence resonance energy transfer, we found that isoLG-adducted peptides and MHC-I interact at the intermolecular level on mouse DCs, suggesting that IsoLG-modified peptides are presented within MHC-I. Co-treatment of these cells with TBHP and BTZ attenuated this interaction compared with TBHP treatment alone (2.9 x 10 3 vs 32.7 x 10 3 /10 6 DCs, N = 9, P < 0.001). Next, mice were treated with angiotensin II (ang II) with or without co-treatment with BTZ. Co-treated animals exhibited reduced mean systolic blood pressure (161.7 ± 7.2 vs 122.9 ± 17.9 mmHg, N = 4-5, P < 0.05) and a reduction in renal macrophages (13.4 x 10 3 vs 6.57 x 10 3 DCs/Kidney, N = 4-5, P < 0.001) and DCs (129.4 x 10 3 vs 79.9 x 10 3 DCs/Kidney, N = 4-5, P < 0.05). These studies provide evidence that the proteasome processes isoLG adducts into peptides that are presented within MHC -I, and that proteasome inhibitors can not only block this process, but in doing so, can reduce renal inflammation and lower blood pressure. Efforts to inhibit processing and presentation of isoLG-modified peptides may therefore have therapeutic benefit in hypertension.

Abstract 108: Sympathetic Inhibition Prevents the Homing of Specific Memory T Cells to the Bone Marrow and the Development of Repeated Hypertension

Effector memory T cells (T EM cells) play a crucial role in hypertension. Formed during an initial blood pressure surge, T EM cells can reside in bone marrow (BM) in a quiescent state for prolonged periods. Upon re-exposure to a hypertensive stimulus, these cells can be reactivated and aggravate hypertension and renal damage. Hypertension is also associated with elevated sympathetic outflow. We hypothesized that sympathetic nerves promote accumulation and reactivation of hypertension-specific T EM cells in the BM. We performed unilateral superior cervical ganglionectomy (SCGx) in C57BL/6 mice, causing sympathectomy of the forelimb on the surgical side. After 2-week Ang II infusion (490 ng/kg/min s.c.), 5х10 6 BM cells from both the SCGx and control limbs were isolated and co-cultured with 0.5х10 6 dendritic cells from other hypertensive mice. We found 30% fewer CD8 + T cell proliferation in the SCGx BM than intact side (1.9±0.2 vs. 2.8±0.1х10 4 , p<0.01), but no difference in CD4 + T cells. To study mechanisms involved in T cell homing, 10 7 pan T cells were isolated from CD45.2 mice after Ang II infusion and adoptively transferred to CD45.1 mice with unilateral SCGx. Flow cytometry indicated that 35% fewer donor CD8 + T EM cells homed to the SCGx than the intact BM 7 days after transfer (5.3±0.8 vs. 8.1±1.5 per 10 4 total T cells, p<0.05). We further determined if systemic sympatho-inhibition during T cell homing is protective against future hypertensive stimuli. We blocked systemic sympathetic outflow by injecting an inhibitory designer receptor exclusively activated by a designer drug (Gi-DREADD) into the rostroventral lateral medulla (RVLM) and performed pan-T cell adoptive transfer 10 days later. The DREADD ligand CNO was given in drinking water 3 days before till 7 days after adoptive transfer. After washout, mice received low dose Ang II infusion (140 ng/kg/min) for 2 weeks. As measured by radiotelemetry, mice with control injection developed hypertension (160±7 mmHg). However, mice with Gi-DREADD expressed in RVLM remained normotensive (136±3 mmHg, p<0.05 vs. control). These data define a novel role of sympathetic nerves in regulation of memory T cell trafficking, and sympathetic inhibition may have long term protective effect beyond lowering blood pressure.

Abstract P281: Artificial Dendritic Cells Identify a Major Histocompatibility Complex Class 1 Subset that Activates T Cells in Hypertension

We and others have shown an important role CD8+ cells in both experimental and human hypertension. CD8+ T cells are activated by antigens presented by major histocompatibility complex 1 (MHC1). C57BL/6 mice express two MHC1, referred to as H2-Kb and H2-Db. To identify antigenic peptides responsible for hypertension, we made two transgenic mice lacking the transmembrane domains of MHC1 and an added His-tag to the modified MHC1. These transgenes are driven by CD11c promoter, allowing expression in antigen presenting cells. The soluble Kb and Db (sKb and sDb) mice received 2 week infusions of sham or angiotensin II and their splenocytes placed in culture for two days. Ni-NTA beads were then used to bind the shed MHC-1 and these beads mixed with 10 6 T cells from other ang II infused mice (Figure panel A). CFSE dilution was used to monitor T cell proliferation. We found that sDb from ang II infused male mice, but not sham infused mice, potently stimulated proliferation of CD8+ T cells from ang II infused male mice. This degree of stimulation was significantly greater than that observed by sKb (Figure panel B). The shed MHC1 from female ang II-treated mice caused significantly less stimulation of female CD8+ T cells compared to male MHC1, in keeping with prior observations that female mice have less immune activation in hypertension. In summary, these data strongly suggest that unique antigens, presented in the context of H2-Db, are generated in hypertension. These data also suggest that there may be unique human lymphocyte antigens (HLAs), the analog of mouse MHC, that predispose to hypertension and related end-organ damage.

Hypertension and increased endothelial mechanical stretch promote monocyte differentiation and activation: roles of STAT3, interleukin 6 and hydrogen peroxide

Aims

Monocytes play an important role in hypertension. Circulating monocytes in humans exist as classical, intermediate, and non-classical forms. Monocyte differentiation can be influenced by the endothelium, which in turn is activated in hypertension by mechanical stretch. We sought to examine the role of increased endothelial stretch and hypertension on monocyte phenotype and function.

Methods and results

Human monocytes were cultured with confluent human aortic endothelial cells undergoing either 5% or 10% cyclical stretch. We also characterized circulating monocytes in normotensive and hypertensive humans. In addition, we quantified accumulation of activated monocytes and monocyte-derived cells in aortas and kidneys of mice with Angiotensin II-induced hypertension. Increased endothelial stretch enhanced monocyte conversion to CD14++CD16+ intermediate monocytes and monocytes bearing the CD209 marker and markedly stimulated monocyte mRNA expression of interleukin (IL)-6, IL-1β, IL-23, chemokine (C-C motif) ligand 4, and tumour necrosis factor α. STAT3 in monocytes was activated by increased endothelial stretch. Inhibition of STAT3, neutralization of IL-6 and scavenging of hydrogen peroxide prevented formation of intermediate monocytes in response to increased endothelial stretch. We also found evidence that nitric oxide (NO) inhibits formation of intermediate monocytes and STAT3 activation. In vivo studies demonstrated that humans with hypertension have increased intermediate and non-classical monocytes and that intermediate monocytes demonstrate evidence of STAT3 activation. Mice with experimental hypertension exhibit increased aortic and renal infiltration of monocytes, dendritic cells, and macrophages with activated STAT3.

Conclusions

These findings provide insight into how monocytes are activated by the vascular endothelium during hypertension. This is likely in part due to a loss of NO signalling and increased release of IL-6 and hydrogen peroxide by the dysfunctional endothelium and a parallel increase in STAT activation in adjacent monocytes. Interventions to enhance bioavailable NO, reduce IL-6 or hydrogen peroxide production or to inhibit STAT3 may have anti-inflammatory roles in hypertension and related conditions.

Abstract 088: The Immune Mechanisms of Salt-Sensitivity

Salt-sensitivity is present in 50% of all hypertensive individuals. Prior studies have focused on the roles of kidney, vasculature and sympathetic activity in salt-sensitivity but the contribution of immune cells is poorly understood. We recently found that in murine dendritic cells amiloride sensitive channels sense salt and trigger NADPH oxidase-dependent formation of isolevuglandin-(IsolG)-adducts. We tested the hypothesis that human monocytes exhibit salt-sensitivity leading to activation via IsoLG-adduct formation and this is associated with cardiovascular risk factors. In a cohort of 18 subjects, we found that the sodium intake, measured by 24 hours urine excretion (UNa) was positively correlated with plasma levels of IsolGs. We also measured accumulation of interstitial sodium in 70 subjects by Magnetic Sodium Resonance and evaluated their circulating monocytes by flow cytometry. Subjects with high skin sodium had higher levels of IsoLGs in their monocytes (24±6 vs 38±6 %, p<0.05) and higher expression of CD83, an activation and dendritic cell marker (0.04 ± 0.009 vs 0.12± 0.04%, p =0.04). To investigate the ability of monocytes to respond to salt, we cultured monocytes from 17 subjects in high salt environment (HS:190 mM NaCl) or normal media (NS:150mM NaCl) for 48 hours. In culture, 47% of the subjects respond to salt, denoted by an increase of at least 20% in IsoLG formation (NS: 1327±240 vs. HS: 2217±653, p =0.009) as well as increased expression of the activation markers CD83 and CD86. The subjects’ cardiovascular risk factors including pulse pressure, BMI, glucose and total cholesterol positively correlated with the amount of IsolGs produced (ΔHS-NS) in response to salt (r=0.51 p<0.05, r=0.66 p=0.005, r=0.55 p<0.05, p=0.72 p=0.003, respectively). Interestingly, 5 pM of Ouabain, a Na-K-ATPase blocker, increased intracellular sodium and expression of CD86 (NS: 98±11, HS: 203 ±16 vs, NS+ Ouabain: 476 ± 58 MFI, p=0.001) and CD83 (NS: 778±90, HS: 1529 ± 94 vs, NS+ Ouabain: 1649 ± 209 MFI, p=0.003). We suggest that in addition to the kidney and vasculature, human monocytes and monocyte derived cells exhibit salt sensitivity, and that this is conveyed by cardiovascular risk factors and activity of the Na-K-ATPase.

Abstract P214: Serum Glucocorticoid Kinase 1 and Sympathetic Nerve Activity in Salt-Sensitive Hypertension

Salt-sensitive hypertension affects nearly 50% of the population and reducing salt intake decreases blood pressure and cardiovascular events in the general population. The precise mechanism of how dietary salt contributes to blood pressure (BP) elevation, renal injury, and cardiovascular disease remains unclear. Substantial evidence supports a role of increased sympathetic output in salt-dependent hypertension and this promotes renal inflammation and dysfunction. It has been shown that salt accumulates in the interstitium of hypertensive humans and animals and drives immune cells toward a proinflammatory phenotype through the salt sensing kinase serum/glucocorticoid kinase 1 (SGK1). We have also shown an important role of monocytes and monocyte-derived dendritic cells in hypertension. In this study, we tested the hypothesis that SGK1 in myeloid CD11c + cells promote salt-sensitive hypertension by increasing sympathetic outflow. To test this hypothesis, we created mice lacking SGK1 in CD11c + cells (SGK1 CreCD11c mice) and used SGK1 fl/fl mice as controls. To induce salt-sensitivity, mice received 0.5 mg/ml of N-Nitro-L-arginine methyl ester hydrochloride (L-NAME) in the drinking water for 2 weeks. This was followed by a 2-week washout period and then a 4% high salt diet for 3 weeks. BP was monitored using telemetry. We found that BP elevation during high salt feeding was significantly attenuated in SGK1 CreCD11c mice compared to SGK1 fl/fl mice (125 ± 1 vs. 141 ± 1 mmHg; p < 0.01). SGK1 CreCD11c mice had a significant reduction in CD45 + , CD3 + , CD4 + CD8 + and CD19 + cells in the kidney compared to SGK1 fl/fl mice as assessed by flow cytometry (p < 0.05). Interestingly, on high salt, SGK1 CreCD11c mice had a significant reduction in heart rate (HR) compared to SGK1 fl/fl mice (528 ± 2 vs. 592 ± 7 bpm; p = 0.006). Microglial cells of the brain express CD11c, and we found that the reduction in HR was associated with a marked reduction in HR variability in SGK1 CreCD11c mice compared to SGK1 fl/fl mice (1.65 ± 0.38 vs. 3.00 ± 0.57; p = 0.0018), indicating a reduction in sympathetic outflow. Our data indicate that SGK1 in CD11c + myeloid cells and likely those of the central nervous system, modulate BP and sympathetic outflow promoting the pathogenesis of salt-sensitive hypertension.

Abstract 127: Axl + Siglec6 + Dendritic Cells: the Role of Salt, Stretch, and Hypertension

We have shown that monocyte-derived dendritic cells (DCs) are activated in hypertension to produce large amounts of cytokines and to activate T cells. DCs from hypertensive mice can convey hypertension when adoptively transferred to recipients. Single cell sequencing has recently identified a novel subset of DCs in humans that express Axl and Sigelc6 + (AS DCs). These cells have been reported to potently drive T cell proliferation and to produce large amounts of IL-8 and IL12. The role of AS DCs in hypertension remains unknown. We isolated total peripheral blood mononuclear cells (PBMCs) from normotensive (n=23) and hypertensive (n=12) patients and assessed DC populations, including AS DCs, using flow cytometry. We found a significant increase in the AS DCs in hypertensive compared to normotensive patients (297 ± 73 vs. 108 ± 26/ml; P=0.0304). In contrast, there were no differences in CD1c + DCs (3398 ± 776 vs. 5245 ± 122/ml) or CD141 + DCs (164 ± 20 vs. 218 ± 49/ml) between normotensive and hypertensive subjects. To investigate the mechanism by which AS DCs are formed in hypertension, we used two in vitro hypertensive stimuli: exposure to salt and hypertensive stretch of adjacent human endothelial cells. Human PBMCs were cultured in either normal NaCl (NS, 150 mM) or high NaCl (HS, 190 mM) for 48 hours. Flow cytometry indicated a striking increase in AS DCs by exposure to HS compared to NS (516 ± 181 vs 201 ± 57/ml) and this was prevented by co-treatment of cells with the salt-sensing Serum Glucocorticoid Kinase 1 inhibitor GSK650394. As a second approach, we co-cultured human aortic endothelial cells (HAECs) with PBMCs from normotensive donors and exposed the HAEC monolayer to either normal (5%) or hypertensive cyclical stretch (10%) for 24 hours. Co-culture of PBMCs with HAECs exposed to 10% stretch doubled AS DCs as compared to PBMCs cultured with HAECs undergoing 5% stretch (1.4 ± 0.5 vs 0.7 ± 0.3%; P=0.0217). These data show that AS DC population are increased in hypertensive patients and that known hypertensive stimuli in vitro promote formation of AS DCs. Thus, AS DCs seem to be an important immune cell subset in human hypertension and might be a novel therapeutic target for this disease.

Differential cell-matrix mechanoadaptations and inflammation drive regional propensities to aortic fibrosis, aneurysm or dissection in hypertension

The embryonic lineage of intramural cells, microstructural organization of the extracellular matrix, local luminal and wall geometry, and haemodynamic loads vary along the length of the aorta. Yet, it remains unclear why certain diseases manifest differentially along the aorta. Toward this end, myriad animal models provide insight into diverse disease conditions-including fibrosis, aneurysm and dissection-but inherent differences across models impede general interpretations. We examined region-specific cellular, matrix, and biomechanical changes in a single experimental model of hypertension and atherosclerosis, which commonly coexist. Our findings suggest that (i) intramural cells within the ascending aorta are unable to maintain the intrinsic material stiffness of the wall, which ultimately drives aneurysmal dilatation, (ii) a mechanical stress-initiated, inflammation-driven remodelling within the descending aorta results in excessive fibrosis, and (iii) a transient loss of adventitial collagen within the suprarenal aorta contributes to dissection propensity. Smooth muscle contractility helps to control wall stress in the infrarenal aorta, which maintains mechanical properties near homeostatic levels despite elevated blood pressure. This early mechanoadaptation of the infrarenal aorta does not preclude subsequent acceleration of neointimal formation, however. Because region-specific conditions may be interdependent, as, for example, diffuse central arterial stiffening can increase cyclic haemodynamic loads on an aneurysm that is developing proximally, there is a clear need for more systematic assessments of aortic disease progression, not simply a singular focus on a particular region or condition.

Reactive species balance via GTP cyclohydrolase I regulates glioblastoma growth and tumor initiating cell maintenance

Background

Depending on the level, differentiation state, and tumor stage, reactive nitrogen and oxygen species inhibit or increase cancer growth and tumor initiating cell maintenance. The rate-limiting enzyme in a pathway that can regulate reactive species production but has not been thoroughly investigated in glioblastoma (GBM; grade IV astrocytoma) is guanosine triphosphate (GTP) cyclohydrolase 1 (GCH1). We sought to define the role of GCH1 in the regulation of GBM growth and brain tumor initiating cell (BTIC) maintenance.

Methods

We examined GCH1 mRNA and protein expression in patient-derived xenografts, clinical samples, and glioma gene expression datasets. GCH1 levels were modulated using lentiviral expression systems, and effects on cell growth, self-renewal, reactive species production, and survival in orthotopic patient-derived xenograft models were determined.

Results

GCH1 was expressed in GBMs with elevated but not exclusive RNA and protein levels in BTICs in comparison to non-BTICs. Overexpression of GCH1 in GBM cells increased cell growth in vitro and decreased survival in an intracranial GBM mouse model. In converse experiments, GCH1 knockdown with short hairpin RNA led to GBM cell growth inhibition and reduced self-renewal in association with decreased CD44 expression. GCH1 was critical for controlling reactive species balance, including suppressing reactive oxygen species production, which mediated GCH1 cell growth effects. In silico analyses demonstrated that higher GCH1 levels in glioma patients correlate with higher glioma grade, recurrence, and worse survival.

Conclusions

GCH1 expression in established GBMs is pro-tumorigenic, causing increased growth due, in part, to promotion of BTIC maintenance and suppression of reactive oxygen species.

Abstract 163: Glioblastoma, cancer stem cells, and reactive species balances: A case for GTP cyclohydrolase 1

Glioblastoma (GBM), or grade IV astrocytoma, is a deadly disease due in part to the high degree of intratumoral heterogeneity that contributes to treatment failures. Previous studies have shown the importance of reactive species balances, partially controlled by the coupling of nitric oxide synthases (NOS) with their cofactor, in maintenance of glioma stem cell (GSC) phenotype as well as survival of cancer cells in general. In this study, we investigated the roles of GTP cyclohydrolase 1 (GCH1), which is the first and rate-limiting enzyme of the pathway producing of NOS cofactor producing pathway, in GBM stem cell phenotypes via redox balances. We found that GCH1 RNA and protein expression were increased in GSCs in comparison to non-GSCs, but that GCH1 was not exclusive to the GSC fraction. Indeed, GCH1 was elevated in GBM in comparison to normal brain. Overexpression of GCH1 in GBM cells increased cell growth in vitro and neurosphere-forming capability and decreased survival in an intracranial GBM mouse model. In contrast, GCH1 knockdown with short hairpin RNA in GBM cells led to growth inhibition in vitro as well as increased survival in animal models. GCH1 increased CD44 expression and was upregulated in the detrimental mesenchymal GBM subtype in which CD44 served as a marker. Mechanistically, we found that the expression of GCH1 increased BH4 production, as well as augmented multiple antioxidant pathways, including the expression of PARK7, was critical for controlling reactive species balance, including suppressing reactive oxygen species production. In silico analyses demonstrated that higher GCH1 levels in glioma patients correlate with higher glioma grade, recurrence and worse survival. Together, our data suggest that upregulation of GCH1 in GSCs promotes tumor maintenance and is a key regulator of reactive oxygen species in GBM, and GCH1 pathway is a potential target for therapy.

Citation Format: Anh N. Tran, Kiera Walker, David G. Harrison, Wei Chen, James Mobley, Lauren Hocevar, James R. Hackney, Randee Sedaka, Jennifer Pollock, Matthew S. Goldberg, Dolores Hambardzumyan, Sara J. Cooper, G Yancey Gillespie, Anita B. Hjelmeland. Glioblastoma, cancer stem cells, and reactive species balances: A case for GTP cyclohydrolase 1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 163.

Dendritic Cell Amiloride-Sensitive Channels Mediate Sodium-Induced Inflammation and Hypertension

Sodium accumulates in the interstitium and promotes inflammation through poorly defined mechanisms. We describe a pathway by which sodium enters dendritic cells (DCs) through amiloride-sensitive channels including the alpha and gamma subunits of the epithelial sodium channel and the sodium hydrogen exchanger 1. This leads to calcium influx via the sodium calcium exchanger, activation of protein kinase C (PKC), phosphorylation of p47^phox, and association of p47^phox with gp91^phox. The assembled NADPH oxidase produces superoxide with subsequent formation of immunogenic isolevuglandin (IsoLG)-protein adducts. DCs activated by excess sodium produce increased interleukin-1β (IL-1β) and promote T cell production of cytokines IL-17A and interferon gamma (IFN-γ). When adoptively transferred into naive mice, these DCs prime hypertension in response to a sub-pressor dose of angiotensin II. These findings provide a mechanistic link between salt, inflammation, and hypertension involving increased oxidative stress and IsoLG production in DCs.

The role of infiltrating immune cells in dysfunctional adipose tissue

Adipose tissue (AT) dysfunction, characterized by loss of its homeostatic functions, is a hallmark of non-communicable diseases. It is characterized by chronic low-grade inflammation and is observed in obesity, metabolic disorders such as insulin resistance and diabetes. While classically it has been identified by increased cytokine or chemokine expression, such as increased MCP-1, RANTES, IL-6, interferon (IFN) gamma or TNFα, mechanistically, immune cell infiltration is a prominent feature of the dysfunctional AT. These immune cells include M1 and M2 macrophages, effector and memory T cells, IL-10 producing FoxP3+ T regulatory cells, natural killer and NKT cells and granulocytes. Immune composition varies, depending on the stage and the type of pathology. Infiltrating immune cells not only produce cytokines but also metalloproteinases, reactive oxygen species, and chemokines that participate in tissue remodelling, cell signalling, and regulation of immunity. The presence of inflammatory cells in AT affects adjacent tissues and organs. In blood vessels, perivascular AT inflammation leads to vascular remodelling, superoxide production, endothelial dysfunction with loss of nitric oxide (NO) bioavailability, contributing to vascular disease, atherosclerosis, and plaque instability. Dysfunctional AT also releases adipokines such as leptin, resistin, and visfatin that promote metabolic dysfunction, alter systemic homeostasis, sympathetic outflow, glucose handling, and insulin sensitivity. Anti-inflammatory and protective adiponectin is reduced. AT may also serve as an important reservoir and possible site of activation in autoimmune-mediated and inflammatory diseases. Thus, reciprocal regulation between immune cell infiltration and AT dysfunction is a promising future therapeutic target.