HIF-1α regulates function and differentiation of myeloid-derived suppressor cells in the tumor microenvironment

Myeloid-derived suppressor cells (MDSCs) are a major component of the immune-suppressive network described in cancer and many other pathological conditions. We demonstrate that although MDSCs from peripheral lymphoid organs and the tumor site share similar phenotype and morphology, these cells display profound functional differences. MDSC from peripheral lymphoid organs suppressed antigen-specific CD8⁺ T cells but failed to inhibit nonspecific T cell function. In sharp contrast, tumor MDSC suppressed both antigen-specific and nonspecific T cell activity. The tumor microenvironment caused rapid and dramatic up-regulation of arginase I and inducible nitric oxide synthase in MDSC, which was accompanied by down-regulation of nicotinamide adenine dinucleotide phosphate–oxidase and reactive oxygen species in these cells. In contrast to MDSC from the spleen, MDSC from the tumor site rapidly differentiated into macrophages. Exposure of spleen MDSC to hypoxia resulted in the conversion of these cells to nonspecific suppressors and their preferential differentiation to macrophages. Hypoxia-inducible factor (HIF) 1α was found to be primarily responsible for the observed effects of the tumor microenvironment on MDSC differentiation and function. Thus, hypoxia via HIF-1α dramatically alters the function of MDSC in the tumor microenvironment and redirects their differentiation toward tumor-associated macrophages, hence providing a mechanistic link between different myeloid suppressive cells in the tumor microenvironment.Myeloid-derived suppressor cells (MDSCs) are one of the major components of the immune-suppressive network responsible for T cell defects in cancer. These cells also contribute to tumor progression via regulation of angiogenesis and tumor cell motility. MDSC is a large group of myeloid cells consisting of immature macrophages (MΦ), granulocytes, and DCs, as well as myeloid cells at earlier stages of differentiation (Sica and Bronte, 2007; Talmadge, 2007; Gabrilovich and Nagaraj, 2009; Peranzoni et al., 2010). In mice, MDSCs express both the myeloid lineage differentiation antigen Gr-1 (Ly6G and Ly6C) and α_M integrin CD11b. Two major groups of MDSCs are now identified: cells with granulocytic (CD11b⁺Ly6G⁺Ly6C^low) and monocytic (CD11b⁺Ly6G⁻Ly6C^high) phenotype (Movahedi et al., 2008; Youn et al., 2008). In humans, MDSCs are generally defined as cells that express CD11b, the common myeloid marker CD33, but lack the expression of markers of mature myeloid and lymphoid cells and the MHC class II molecule HLA-DR (Almand et al., 2001; Zea et al., 2005; Diaz-Montero et al., 2009; Nagaraj et al., 2010). In tumor-free mice, MDSCs represent ∼30% of the normal BM cells and <3% of all nucleated splenocytes. In tumor-bearing mice, this population undergoes dramatic expansion. In many tumor models the proportion of MDSC represents >20% of all splenocytes, and MDSCs are easily detectable in tumors and lymph nodes (Kusmartsev and Gabrilovich, 2006; Rabinovich et al., 2007; Sica and Bronte, 2007; Gabrilovich and Nagaraj, 2009). Similar expansion, albeit to a lesser degree, is observed in patients with cancer. In the presence of appropriate cytokines in vitro and after adoptive transfer in vivo, MDSC can differentiate into mature myeloid cells (Kusmartsev and Gabrilovich, 2003). This differentiation is blocked, however, in the presence of tumor cell–conditioned media or in tumor-bearing hosts (Kusmartsev and Gabrilovich, 2003; Talmadge, 2007).Extensive studies in recent years suggested several mechanisms of MDSC-mediated immune suppression that involve arginine (Bronte and Zanovello, 2005; Rodríguez and Ochoa, 2008) and cysteine (Srivastava et al., 2010) metabolism, expression of some surface molecules (Pan et al., 2010), up-regulation of reactive oxygen species (ROS), and production of different cytokines (Talmadge, 2007; Gabrilovich and Nagaraj, 2009). Practically all these studies were performed with MDSC isolated from peripheral lymphoid organs (mostly spleen).Although an important role of MDSC in tumor-associated immune suppression is well established in recent years, its nature remains unclear. One of the major unresolved questions is the role of MDSCs in peripheral lymphoid organs and tumor tissues as well as their relationship with MΦ and DCs. The main paradox is that, despite the presence of a large number of MDSCs in spleens and lymph nodes of tumor-bearing mice and in the peripheral blood of cancer patients with advanced disease, T cells mostly retain the ability to respond to different tumor-nonspecific stimuli including viruses, lectins, costimulatory molecules, IL-2, and stimulation with CD3- and CD28-specific antibodies (Fricke et al., 2007; Monu and Frey, 2007; Nagaraj et al., 2007). In a sharp contrast, T cells directly isolated from tumors display profound defects in their ability to respond to those stimuli (Rabinowich et al., 1996; Lopez et al., 1998; Reichert et al., 2002). Some evidence may suggest that MDSC-mediated immune suppression in peripheral lymphoid organs could be mainly tumor antigen specific. MDSCs mediate antigen-specific T cell tolerance by taking up soluble antigens, including tumor-associated antigens, processing them, and presenting them to CD8⁺ T cells in the context of MHC class I (Kusmartsev et al., 2005; Movahedi et al., 2008).The role of tumor-associated MDSC remains largely obscure. Despite the fact that the cells with the phenotype of MDSC are abundantly present in tumor tissues but are often referred to as monocytes, MΦ, or granulocytes, the relationship (or lack thereof) between MDSC and tumor-associated macrophages (TAMs) is unclear. This confusion is derived from the difficulties in clearly defining the phenotype of myeloid cells in the tumor site. This creates a convoluted, rather incoherent picture of the various functions of different myeloid cell subsets within the tumor. Ambiguity of the biological role of and the relationship between different myeloid cell populations within the tumor site severely limits our understanding of the biology of tumor progression and the development of targeted therapeutics.In this study, we addressed this issue by investigating the function and differentiation of MDSC at the tumor site using an experimental model where tumors were generated as ascites. This allowed for a rapid isolation of cells and enabled direct experiments with adoptive transfer of MDSC directly into the tumor microenvironment. In this paper, we report that MDSCs in tumor-bearing mice display a biological dichotomy regulated by the tumor microenvironment. In peripheral lymphoid organs, MDSC primarily caused antigen-specific T cell nonresponsiveness, which was mediated by ROS. In contrast, within tumor microenvironment, MDSC with the same phenotype and morphology had low ROS levels but dramatically up-regulated NO production and arginase activity, which caused suppression of antigen-nonspecific T cell functions. In contrast to MDSC from the spleen, MDSC in the tumor microenvironment rapidly differentiated primarily into TAM. This process was mediated primarily by hypoxia via hypoxia-inducible factor (HIF) 1α. Our data thus help to explain the differences in the nature of T cell suppression between tumor and peripheral lymphoid organs in tumor-bearing hosts and suggest a regulatory pathway of myeloid cell function in the tumor microenvironment.     

Clinical significance and prognostic value of tumor necrosis factor-α and dickkopf related protein-1 in ankylosing spondylitis

BACKGROUND Ankylosing spondylitis(AS)frequently occurs in people aged 30-45 years,and its prevalence is generally believed to be between 0.1%and 1.4%globally.At present,the“gold standard”for diagnosis of AS requires the provision of pelvic X-rays,which makes it more difficult to perform in population-based epidemiological studies.Therefore,the identification of serological indicators related to the diagnosis,treatment,and prognosis of AS patients is of great significance.AIM To analyze the therapeutic,diagnostic significance and prognostic value of dickkopf-related protein-1(DKK-1)and tumor necrosis factor-α(TNF-α)in AS.METHODS A total of 113 patients with active AS were selected as the research group,and 100 healthy subjects who underwent physical examination were selected as the control group.The levels of DKK-1 and TNF-α in peripheral blood in the two groups were compared.The diagnostic and predictive values of DKK-1 and TNF-α for AS were analyzed with ROC curves,and the factors influencing AS recurrence were analyzed with COX regression.RESULTS Before treatment,the research group showed lower DKK-1 levels but higher TNF-αlevels than the control group(both aP<0.05).In the research group,DKK-1 was up-regulated and TNF-αwas down-regulated after 12 wk of treatment(aP<0.05).The area under the curve,sensitivity and specificity of DKK-1 combined with TNF-αfor diagnosing AS were 0.934,82.30%and 97.00%,respectively.Before treatment,the area under the curve,cutoff value,sensitivity and specificity of DKK-1 for predicting the curative effect were 0.825,68.42 pg/mL,73.68%and 80.00%,respectively,and those of TNF-αwere 0.863,32.79 ng/L,92.11%and 77.33%,respectively.DKK-1 and TNF-αlevels after treatment were closely related to the curative effect(aP<0.05).C-reactive protein,the Bath Ankylosing Spondylitis Disease Activity Index,DKK-1,and TNF-αwere risk factors for AS recurrence(aP<0.05).CONCLUSION DKK-1 and TNF-αare effective in the diagnosis and treatment of AS and are risk factors for its recurrence.In addition,DKK-1 may be a potential target for the diagnosis of AS.     

Age-related changes in strength, joint laxity, and walking patterns: are they related to knee osteoarthritis?

BACKGROUND AND PURPOSE: Aging is associated with musculoskeletal changes and altered walking patterns. These changes are common in people with knee osteoarthritis (OA) and may precipitate the development of OA. We examined age-related changes in musculoskeletal structures and walking patterns to better understand the relationship between aging and knee OA. METHODS: Forty-four individuals without OA (15 younger, 15 middle-aged, 14 older adults) and 15 individuals with medial knee OA participated. Knee laxity, quadriceps femoris muscle strength (force-generating capacity), and gait were assessed. RESULTS: Medial laxity was greater in the OA group, but there were no differences between the middle-aged and older control groups. Quadriceps femoris strength was less in the older control group and in the OA group. During the stance phase of walking, the OA group demonstrated less knee flexion and greater knee adduction, but there were no differences in knee motion among the control groups. During walking, the older control group exhibited greater quadriceps femoris muscle activity and the OA group used greater muscle co-contraction. DISCUSSION AND CONCLUSION: Although weaker, the older control group did not use truncated motion or higher co-contraction. The maintenance of movement patterns that were similar to the subjects in the young control group may have helped to prevent development of knee OA. Further investigation is warranted regarding age-related musculoskeletal changes and their influence on the development of knee OA.     

Aside from acute renal failure cases,are urinary markers of glomerular and tubular function useful in clinical practice?

The qualitative evaluation of proteinuria represents a crucial diagnostic step in clinical practice for the classification of renal diseases according to glomerular, tubulo-interstitial, mixed injury or related to monoclonal gammopathy. Combined with the quantitative evaluation, it also allows an assessment of the disease's severity and prognosis as well as the response to treatment. The development of the urine protein profile (UPP) combines specific urine protein assays on a urine spot analyzing glomerular protein markers such as albumin, transferrin and immunoglobulin G, and tubular markers such as alpha-1microglobulin and retinol binding protein, to generate a detailed quantitative and qualitative proteinuria assessment. This short overview proposes to illustrate the diagnostic and prognostic usefulness of UPP in different common clinical situations.     

ADAM-9, ADAM-15, and ADAM-17 are upregulated in macrophages in advanced human atherosclerotic plaques in aorta and carotid and femoral arteries—Tampere vascular study

Background and aims. The expression of disintegrin and metalloprotease ADAM-9, ADAM-15, and ADAM-17 has been associated with cell-cell, cell-platelet, and cell-matrix interactions and inflammation. They are possibly implicated in the pathophysiology of atherosclerosis.

Methods and results. Whole-genome expression array and quantitative real-time polymerase chain reaction (PCR) analysis confirmed that ADAM-9, ADAM-15, and ADAM-17 are upregulated in advanced human atherosclerotic lesions in samples from carotid, aortic, and femoral territories compared to samples from internal thoracic artery (ITA) free of atherosclerotic plaques. Western analysis indicated that the majority of these ADAMs were in the catalytically active form. ADAM-9, ADAM-15, and ADAM-17-expressing cells were shown to co-localize with CD68-positive cells of monocytic origin in the atherosclerotic plaques using immunohistochemistry and double-staining immunofluorescence analysis. Co-localization was demonstrated in all vascular territories. In the carotid territory, cells expressing the ADAMs co-distributed also with smooth muscle cells and, in femoral territory, with CD31-positive endothelial cells, indicating that the ADAM expression pattern depends on vascular bed territory.

Conclusions. Present findings provide strong evidence for the involvement of catalytically active ADAM-9, ADAM-15, and ADAM-17 in advanced atherosclerosis, most notably associated with cells of monocytic origin.     

Serum tumour markers CA 15-3, TPA,TPS, hCG β and TATI in the monitoring of chemotherapy response in metastatic breast cancer

The clinical utility of CA 15-3, polypeptide specific antigen (TPS), tissue polypeptide antigen (TPA), human chorionic gonadotropin (hCGbeta) and tumourassociated trypsin inhibitor (TATI ) as indicators of chemotherapy response was assessed in advanced breast cancer. Serum was prospectively collected in one center before treatment (after the first course of chemotherapy) and at response evaluation from 57 patients taking part in a multicentre randomized trial comparing docetaxel with sequential methotrexate and 5-fluorouracil in the treatment of advanced breast cancer. The pretreatment levels of the serum markers were not predictors of the later response to treatment. Changes in the TPS level showed the strongest association with clinical response after the first course of chemotherapy and CA 15-3 at the best response evaluation. However, distinct mismatches occurred with every marker. The most problematic error was an increase in marker levels in patients with clinical responses, which might have caused interruption of therapy. This occurred in 8% and 17% of patients after the first course of chemotherapy and in 4% and 17% of patients at the best response evaluation with CA 15-3 and TPS, respectively. Moreover, after the first course of chemotherapy only 39% and 33% of the patients with progressive disease could be identified on the basis of increasing levels of CA 15-3 and TPS, respectively. Later, at clinical disease progression, TPA and TPS were found to be better indicators of disease progression than CA 15-3. In conclusion, changes in CA 15-3 or TPS levels usually correlate with clinical response, but owing to distinct discordances, they should not be used as sole indicators of response to chemotherapy in advanced breast cancer.     

Insulin sensitivity, β-cell function, and incretin effect in individuals with elevated 1-hour postload plasma glucose levels

OBJECTIVE

Individuals with normal glucose tolerance (NGT), whose 1-h postload plasma glucose is ≥155 mg/dL (NGT 1h-high), have an increased risk of type 2 diabetes. The purpose of this study was to characterize their metabolic phenotype.

RESEARCH DESIGN AND METHODS

A total of 305 nondiabetic offspring of type 2 diabetic patients was consecutively recruited. Insulin secretion was assessed using both indexes derived from oral glucose tolerance test (OGTT) and intravenous glucose tolerance test (IVGTT). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp.

RESULTS

Compared with individuals with a 1-h postload plasma glucose <155 mg/dL (NGT 1h-low), NGT 1h-high individuals exhibited lower insulin sensitivity after adjustment for age, sex, and BMI. Insulin secretion estimated from the OGTT did not differ between the two groups of individuals. By contrast, compared with NGT 1h-low individuals, the acute insulin response during an IVGTT and the disposition index were significantly reduced in NGT 1h-high individuals after adjustment for age, sex, and BMI. Incretin effect, estimated as the ratio between total insulin responses during OGTT and IVGTT, was higher in NGT 1h-high individuals compared with NGT 1h-low individuals.

CONCLUSIONS

NGT 1h-high individuals may represent an intermediate state of glucose intolerance between NGT and type 2 diabetes characterized by insulin resistance and reduced β-cell function, the two main pathophysiological defects responsible for the development of type 2 diabetes. Postload hyperglycemia is the result of an intrinsic β-cell defect rather than impaired incretin effect.Impaired glucose tolerance (IGT) identifies individuals with a dysglycemic condition intermediate between normal glucose tolerance (NGT) and type 2 diabetes (1). Individuals with IGT are at high risk for the future development of type 2 diabetes, and several clinical trials have shown that both lifestyle changes and pharmacological intervention prevent/halt the progression from IGT to overt type 2 diabetes (2–5). The results of these intervention studies highlight the importance of identifying individuals at high risk for type 2 diabetes in order to offer them an intervention program to reduce the incidence of the disease, and recently new guidelines for the screening of individuals for type 2 diabetes risks and diabetes prevention have been developed by a European multidisciplinary consortium (the Development and Implementation of a European Guideline and Training Standards for Diabetes Prevention [IMAGE] project) to provide evidence-based recommendations for health care practitioners, organizations, and funders on the prevention of type 2 diabetes in European health care settings (6,7). It is important to note that all clinical trials that have evaluated the impact of intervention strategies for preventing type 2 diabetes have recruited subjects with IGT (2–5). However, longitudinal studies have demonstrated that over one-third of individuals who develop type 2 diabetes have NGT at baseline (8), indicating that the use of IGT or impaired fasting glucose (IFG) categories as the sole means of identifying individuals at high risk for type 2 diabetes may overlook a considerable proportion of individuals who will develop type 2 diabetes over time. Recently, it has been reported that a cutoff of 155 mg/dL for 1-h postload plasma glucose during an oral glucose tolerance test (OGTT) can identify individuals at high risk for development of type 2 diabetes among those who have NGT (NGT 1h-high) (9–11). Addition of HbA_1c levels to 1-h postload plasma glucose levels significantly increased their respective power in predicting development of type 2 diabetes risk, indicating that additional information about type 2 diabetes risk is embedded in HbA_1c (12). Importantly, NGT 1h-high individuals exhibit early signs of subclinical organ damage including vascular atherosclerosis (13), reduced estimated glomerular filtration rate (14), left ventricular hypertrophy (15), and left ventricular diastolic dysfunction (16). The metabolic abnormalities responsible for 1-h postload hyperglycemia remain to be elucidated. Impaired insulin sensitivity and failure of pancreatic β-cells to compensate for the enhanced insulin demand are the principal factors responsible for the development and progression of type 2 diabetes. It is possible that defects in β-cells function and/or in the incretin effect occur at an earlier stage than IGT, i.e., in individuals who are considered to have NGT according to current diagnostic criteria. To gain a more deep insight into the metabolic abnormalities characterizing NGT 1h-high individuals, we evaluated insulin sensitivity assessed by hyperinsulinemic-euglycemic clamp as well as insulin secretion and the incretin effect by using both OGTT and intravenous glucose tolerance test (IVGTT) in a cohort of nondiabetic offspring of type 2 diabetic patients.     

How are cognitive impairment,fatigue and signs of depression related to participation in daily life among persons with multiple sclerosis?

Abstract

Purpose: Factors that impact participation are of scientific and clinical importance. Participation in everyday activities among persons with multiple sclerosis (MS) can be compromised by various factors however the combined contribution of these factors to participation has not been explored. The aim of this study was to describe the relationship between cognitive impairment, physical disability and signs of depression and participation in daily life among persons with MS. Methods: Data from 200 participants were collected in an observational, prospective study. The majority was female, had mild physical disability, and an average age of 48.7. The impact of independent variables, including demographic and disease related data, levels of cognitive impairment, signs of depression and fatigue, on participation was investigated using path analysis. Results: Cognitive impairment was associated with restricted participation in domestic, leisure and outdoor domains. Restrictions in leisure and outdoor activities, but not domestic activities were related to signs of depression. Cognitive impairment was associated with the level of education and the level of physical disability. Conclusions: Increasing participation is an important outcome of rehabilitation. The results of this study suggest a multifactorial approach to intervention that considers physical, mental and emotional component to maximize participation among persons with MS.

• Implications for Rehabilitation

• Rehabilitation for persons living with multiple sclerosis (MS) should incorporate careful evaluation of physical disability, cognitive impairment and depression and their impact on participation.

• Clinicians need to evaluate participation in a variety of daily activities, including activities within and outside of the home, and leisure activities.

• Signs of depression may have a greater impact on participation in outdoor and leisure activities then on other activities.

     

Changes of energy metabolism,nutritional status and serum cytokine levels in patients with Crohn’s disease after anti-tumor necrosis factor-α therapy

We investigated the effects of treatment with antibodies against tumor necrosis factor (TNF)-α on energy metabolism, nutritional status, serum cytokine levels in patients with Crohn’s disease (CD). Twelve patients were enrolled. Resting energy expenditure (REE) levels were measured by indirect calorimetry. Crohn’s disease activity index (CDAI) significantly decreased after treatment with anti-TNF-α therapy. Anti-TNF-α therapy did not affect REE, but respiratory quotient (RQ) significantly increased after treatment. Serum interleukin-6 levels were significantly decreased and RQ were significantly increased in high REE (≥25 kcal/kg/day) group as compared to low REE (<25 kcal/kg/day) group. In conclusion, high REE value on admission is a predictive factor for good response to treatment with anti-TNF-α antibodies in active CD patients.     

Atorvastatin inhibits inflammatory angiogenesis in mice through down regulation of VEGF,TNF-α and TGF-β1

While compelling evidence indicates beneficial effects of statins on inflammatory processes, besides their cholesterol-lowering activities, the actions on angiogenesis are less clear-cut. Our aim was to investigate the effects of atorvastatin on key components of inflammatory angiogenesis in the murine sponge model. Polyester-polyurethane sponges, used as a framework for fibrovascular tissue growth, were implanted in Swiss mice. Atorvastatin (0.6, 3 mg/kg/day) was given orally for 8 days in drinking water. The implants collected at day 9 postimplantation were processed for the assessement of hemoglobin, myeloperoxidase (MPO), N-acetylglucosaminidase (NAG) and collagen. Relevant inflammatory, angiogenic and fibrogenic cytokines were also determined. Atorvastatin treatment resulted in significant decrease in sponge vascularization (Hb content) and in VEGF levels at both doses. Neutrophil influx (MPO activity) was not affected by the compound whereas macrophage recruitment (NAG activity) was inhibited, suggesting a degree of selectivity by atorvastatin for this cell population. The level of CCL2 (MCP1-JE) was decreased only with 0.6 mg/kg. Atorvastatin was also able to reduce collagen deposition and the levels of transforming growth factor (TGF-β1) intraimplant, dose-dependently. The inhibitory function of atorvastatin on multiple parameters of main components of inflammatory angiogenesis revealed in this study is clearly associated with the modulatory effects of HMG-CoA reductase on VEGF, TNF-α and TGF-β1 production.     

Associations Between [18F]FDG-PET and Complex Histopathological Parameters Including Tumor Cell Count and Expression of KI 67, EGFR,VEGF, HIF-1α, and p53 in Head and Neck Squamous Cell Carcinoma

Molecular Imaging and Biology - Head and neck squamous cell carcinoma (HNSCC) is one of common cancers worldwide. Positron emission tomography (PET) with 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG)...     

Effect of soluble corn fiber supplementation for 1 year on bone metabolism in children,the MetA-bone trial: Rationale and design

Calcium intake is critical for adequate bone mineralization in adolescence, but it is usually inadequate in US adolescents. A strategy to maximize bone mineralization is to increase calcium absorption, which could be achieved by soluble corn fiber (SCF). There are no studies determining the long-term effects of SCF on bone mass in children.ObjectivesTo determine the effect of one-year SCF supplementation compared to placebo on bone mass and bone biomarkers in children with low habitual calcium intake. We hypothesize that SCF supplementation will result in a higher bone mineral content and higher levels of bone formation and lower bone resorption biomarkers.Methods240 healthy children (10–13 years), with usual low calcium intake, will be randomized to four experimental groups for 1 year: (1) SCF (12 g/d); (2) SCF (12 g/d) + 600 mg/d of calcium; (3) Placebo (maltodextrin); and (4) Placebo +600 mg/d of calcium. The supplements have been pre-mixed with a flavored powder beverage and participants will only need to dilute it in water and drink this twice per day. Bone will be measured using dual energy x-ray absorptiometry (DXA) at baseline, 6 and 12 months. Serum bone biomarkers will be measured at baseline and at 12 months.ConclusionsIf supplementing diets with SCF lead to higher bone mass during adolescence, this could help achieve the genetic potential for PBM and to start adult life with stronger bones. If successful, SCF can be incorporated into diets for promoting bone health in adolescents.