Induction of interleukin 6 (IL-6) by hypoxia in vascular cells. Central role of the binding site for nuclear factor-IL-6

Quasi-spatial single-cell transcriptome based on physical tissue properties defines early aging associated niche in liver

Aging is associated with the accumulation of senescent cells, which are triggered by tissue injury response and often escape clearance by the immune system. The specific traits and diversity of these cells in aged tissues, along with their effects on the tissue microenvironment, remain largely unexplored. Despite the advances in single-cell and spatial omics technologies to understand complex tissue architecture, senescent cell populations are often neglected in general analysis pipelines due to their scarcity and the technical bias in current omics toolkits. Here we used the physical properties of tissue to enrich the age-associated fibrotic niche and subjected them to single-cell RNA sequencing and single-nuclei ATAC sequencing (ATAC-seq) analysis and named this method fibrotic niche enrichment sequencing (FiNi-seq). Fibrotic niche of the tissue was selectively enriched based on its resistance to enzymatic digestion, enabling quasi-spatial analysis. We profiled young and old livers of male mice using FiNi-seq, discovered Wif1- and Smoc1-producing mesenchymal cell populations showing senescent phenotypes, and investigated the early immune responses within this fibrotic niche. Finally, FiNi-ATAC-seq revealed age-associated epigenetic changes enriched in fibrotic niche cells. Thus, our quasi-spatial, single-cell profiling method allows the detailed analysis of initial aging microenvironments, providing potential therapeutic targets for aging prevention.

The role of torso stiffness and prediction in the biomechanics of anxiety: a narrative review

Although anxiety is a common psychological condition, its symptoms are related to a cardiopulmonary strain which can cause palpitation, dyspnea, dizziness, and syncope. Severe anxiety can be disabling and lead to cardiac events such as those seen in Takotsubo cardiomyopathy. Since torso stiffness is a stress response to unpredictable situations or unexpected outcomes, studying the biomechanics behind it may provide a better understanding of the pathophysiology of anxiety on circulation, especially on venous impedance. Any degree of torso stiffness related to anxiety would limit venous return, which in turn drops cardiac output because the heart can pump only what it receives. Various methods and habits used to relieve stress seem to reduce torso stiffness. Humans are large obligatory bipedal upright primates and thus need to use the torso carefully for smooth upright activities with an accurate prediction. The upright nature of human activity itself seems to contribute to anxiety due to the needed torso stiffness using the very unstable spine. Proper planning of actions with an accurate prediction of outcomes of self and non-self would be critical to achieving motor control and ventilation in bipedal activities. Many conditions linked to prediction errors are likely to cause various degrees of torso stiffness due to incomplete learning and unsatisfactory execution of actions, which will ultimately contribute to anxiety. Modifying environmental factors to improve predictability seems to be an important step in treating anxiety. The benefit of playful aerobic activity and proper breathing on anxiety may be from the modulation of torso stiffness and enhancement of central circulation resulting in prevention of the negative effect on the cardiopulmonary system.

Detrimental interactions of hypoxia and complement MASP-1 in endothelial cells as a model for atherosclerosis-related diseases

Both hypoxia and the complement lectin pathway (CLP) are involved in atherosclerosis and atherosclerosis-related stroke and acute myocardial infarction (AMI). We have previously shown that mannose-binding lectin-associated serine protease-1 (MASP-1), the most abundant enzyme of CLP, induces an inflammatory phenotype of endothelial cells (ECs) by cleaving protease activated receptors (PARs). In the absence of data, we aimed to investigate whether hypoxia and MASP-1 interact at the level of ECs, to better understand their role in atherosclerosis-related diseases. Hypoxia attenuated the wound healing ability of ECs, increased ICAM-1 and decreased ICAM-2 expression and upregulated PAR2 gene expression. Hypoxia and MASP-1 increased GROα and IL-8 production, and endothelial permeability without potentiating each other's effects, whereas they cooperatively disrupted vascular network integrity, activated the Ca2+, CREB and NFκB signaling pathways, and upregulated the expression of E-selectin, a crucial adhesion molecule in neutrophil homing. VCAM-1 expression was not influenced either by hypoxia, or by MASP-1. In summary, hypoxia potentiates the effect of MASP-1 on ECs, at least partially by increasing PAR expression, resulting in interaction at several levels, which may altogether exacerbate stroke and AMI progression. Our findings suggest that MASP-1 is a potential drug target in the acute phase of atherosclerosis-related diseases.

ADAR1 regulates macrophage polarization and is protective against liver ischemia and reperfusion injury

Liver ischemia and reperfusion injury (LIRI) is a major risk for the poor prognosis of patients receiving liver transplantation. The molecular mechanism involved in LIRI is complex and related to various cellular components. We previously reported that adenosine deaminase acting on RNA 1 (ADAR1) alleviated the allogeneic skin graft rejection by regulating macrophage polarization. However, the regulatory effects of ADAR1 on liver macrophages after LIRI remain largely unknown. In this study, we mainly adopted a mouse model of LIRI and cellular experiments with hypoxia and reoxygenation (HR) treatment to explore the regulatory roles of ADAR1 on liver macrophages under LIRI conditions. We found that IRI caused decreased ADAR1 in liver tissues and remarkable changes of liver macrophage polarization and profiles. ADAR1 supplementation alleviated the pathological injury caused by IRI and accelerated the activation of M2 macrophages in the liver of IRI mice. Increased hypoxia duration reduced ADAR1 expression levels in murine RAW264.7 macrophages at the transcriptional level. Further overexpression of ADAR1 significantly increased the expressions of anti-inflammatory cytokines and promoted M2 polarization of macrophages under HR exposure. ADAR1 knockdown exhibited opposite effects on macrophage polarization. Hence, ADAR1 promotes the M2 polarization of liver macrophages that may further alleviate LIRI. The protective effects of ADAR1 against LIRI provide a novel insight into the prevention and treatment of LIRI.

Overcoming cancer-associated fibroblast-induced immunosuppression by anti-interleukin-6 receptor antibody

Cancer-associated fibroblasts (CAFs) are a critical component of the tumor microenvironment and play a central role in tumor progression. Previously, we reported that CAFs might induce tumor immunosuppression via interleukin-6 (IL-6) and promote tumor progression by blocking local IL-6 in the tumor microenvironment with neutralizing antibody. Here, we explore whether an anti-IL-6 receptor antibody could be used as systemic therapy to treat cancer, and further investigate the mechanisms by which IL-6 induces tumor immunosuppression. In clinical samples, IL-6 expression was significantly correlated with α-smooth muscle actin expression, and high IL-6 cases showed tumor immunosuppression. Multivariate analysis showed that IL-6 expression was an independent prognostic factor. In vitro, IL-6 contributed to cell proliferation and differentiation into CAFs. Moreover, IL-6 increased hypoxia-inducible factor 1α (HIF1α) expression and induced tumor immunosuppression by enhancing glucose uptake by cancer cells and competing for glucose with immune cells. MR16-1, a rodent analog of anti-IL-6 receptor antibody, overcame CAF-induced immunosuppression and suppressed tumor progression in immunocompetent murine cancer models by regulating HIF1α activation in vivo. The anti-IL-6 receptor antibody could be systemically employed to overcome tumor immunosuppression and improve patient survival with various cancers. Furthermore, the tumor immunosuppression was suggested to be induced by IL-6 via HIF1α activation.

Varied hypoxia adaptation patterns of embryonic brain at different development stages between Tibetan and Dwarf laying chickens

BACKGROUND

Tibetan chickens (Gallus gallus; TBCs), an indigenous breed distributed in the Qinghai-Tibet Plateau, are well adapted to the hypoxic environment. Currently, the molecular genetic basis of hypoxia adaptation in TBCs remains unclear. This study investigated hypoxia adaptation patterns of embryonic brain at different development stages by integrating analysis of the transcriptome with our previously published metabolome data in TBCs and Dwarf Laying Chickens (DLCs), a lowland chicken breed.

RESULTS

During hypoxia, the results revealed that 1334, 578, and 417 differentially expressed genes (DEGs) (|log2 fold change|>1, p-value < 0.05) on days 8, 12, and 18 of development, respectively between TBCs and DLCs. Gene Ontology (GO) and pathway analyses revealed that DEGs are mainly related to metabolic pathways, vessel development, and immune response under hypoxia. This is consistent with our metabolome data that TBCs have higher energy metabolism than DLCs during hypoxia. Some vital DEGs between TBCs and DLCs, such as EPAS1, VEGFD, FBP1, FBLN5, LDHA, and IL-6 which are involved in the HIF pathway and hypoxia regulation.

CONCLUSION

These results suggest varied adaptation patterns between TBCs and DLCs under hypoxia. Our study provides a basis for uncovering the molecular regulation mechanism of hypoxia adaptation in TBCs and a potential application of hypoxia adaptation research for other animals living on the Qinghai-Tibet Plateau, and may even contribute to the study of brain diseases caused by hypoxia.

Knockdown of interleukin-6 plays a neuroprotective role against hypoxia-ischemia in neonatal rats via inhibition of caspase 3 and Bcl-2-associated X protein signaling pathway

This study aimed to investigate the role of interleukin-6 (IL-6) in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (NHIE). Sprague-Dawley (SD) rats were used for the establishment of hypoxic-ischemic (HI) model. The Zea-Longa scoring was used to evaluate the extent of the neurological deficits. Triphenyl tetrazolium chloride (TTC) staining was used to measure the volume of infarction in the brain following HI protocol. The expression of IL-6 in the cortex and/or hippocampus at multiple time points after HI was examined by immunohistochemistry, western blotting and immunofluorescence. Moreover, small interfering RNAs (siRNA) were used to inhibit the expression of IL-6 in-vitro and in-vivo, and the concomitant expression of the Bcl-2 associated X protein (BAX) and caspase 3 was also measured. HI induced a significant brain damage, and these pathological changes were accompanied by IL-6 upregulation which was found localized in cortical neurons. The inhibition of IL-6 expression fostered neuronal and axonal growth, and a reduction in cellular apoptosis in cortical neuronal cultures, and cortex and hippocampus of neonatal rats. The expression of apoptotic markers such as BAX and caspase 3 was closely associated with IL-6. Downregulation of IL-6 could ameliorate HI-induced deficiencies by mediating the expression of caspase 3 and BAX.

The Chromatin-Oxygen Sensor Gene KDM5C Associates with Novel Hypoxia-Related Signatures in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a fatal brain tumor without effective drug treatment. In this study, we highlight, for the first time, the contribution of chromatin remodeling gene Lysine (K)-specific demethylase 5C (KDM5C) in GBM via an extensive analysis of clinical, expression, and functional data, integrated with publicly available omic datasets. The expression analysis on GBM samples (N = 37) revealed two informative subtypes, namely KDM5C^High and KDM5C^Low, displaying higher/lower KDM5C levels compared to the controls. The former subtype displays a strong downregulation of brain-derived neurotrophic factor (BDNF)—a negative KDM5C target—and a robust overexpression of hypoxia-inducible transcription factor-1A (HIF1A) gene, a KDM5C modulator. Additionally, a significant co-expression among the prognostic markers HIF1A, Survivin, and p75 was observed. These results, corroborated by KDM5C overexpression and hypoxia-related functional assays in T98G cells, suggest a role for the HIF1A-KDM5C axis in the hypoxic response in this tumor. Interestingly, fluorescence-guided surgery on GBM sections further revealed higher KDM5C and HIF1A levels in the tumor rim niche compared to the adjacent tumor margin, indicating a regionally restricted hyperactivity of this regulatory axis. Analyzing the TCGA expression and methylation data, we found methylation changes between the subtypes in the genes, accounting for the hypoxia response, stem cell differentiation, and inflammation. High NANOG and IL6 levels highlight a distinctive stem cell-like and proinflammatory signature in the KDM5C^High subgroup and GBM niches. Taken together, our results indicate HIF1A-KDM5C as a new, relevant cancer axis in GBM, opening a new, interesting field of investigation based on KDM5C as a potential therapeutic target of the hypoxic microenvironment in GBM.

Basic mechanisms in cardiogenic shock: part 1-definition and pathophysiology

Cardiogenic shock mortality rates remain high despite significant advances in cardiovascular medicine and the widespread uptake of mechanical circulatory support systems. Except for early invasive angiography and percutaneous coronary intervention of the infarct-related artery, the most widely used therapeutic measures are based on low-quality evidence. The grim prognosis and lack of high-quality data warrant further action. Part 1 of this two-part educational review defines cardiogenic shock and discusses current treatment strategies. In addition, we summarize current knowledge on basic mechanisms in the pathophysiology of cardiogenic shock, focusing on inflammation and microvascular disturbances, which may ultimately be translated into diagnostic or therapeutic approaches to improve the outcome of our patients.

The endothelial glycocalyx in critical illness: A pediatric perspective

The vascular endothelium is the interface between circulating blood and end organs and thus has a critical role in preserving organ function. The endothelium is lined by a glycan-rich glycocalyx that uniquely contributes to endothelial function through its regulation of leukocyte and platelet interactions with the vessel wall, vascular permeability, coagulation, and vasoreactivity. Degradation of the endothelial glycocalyx can thus promote vascular dysfunction, inflammation propagation, and organ injury. The endothelial glycocalyx and its role in vascular pathophysiology has gained increasing attention over the last decade. While studies characterizing vascular glycocalyx injury and its downstream consequences in a host of adult human diseases and in animal models has burgeoned, studies evaluating glycocalyx damage in pediatric diseases are relatively few. As children have unique physiology that differs from adults, significant knowledge gaps remain in our understanding of the causes and effects of endothelial glycocalyx disintegrity in pediatric critical illness. In this narrative literature overview, we offer a unique perspective on the role of the endothelial glycocalyx in pediatric critical illness, drawing from adult and preclinical data in addition to pediatric clinical experience to elucidate how marked derangement of the endothelial surface layer may contribute to aberrant vascular biology in children. By calling attention to this nascent field, we hope to increase research efforts to address important knowledge gaps in pediatric vascular biology that may inform the development of novel therapeutic strategies.

HIF-1α modulates sex-specific Th17/Treg responses during hepatic amoebiasis

BACKGROUND & AIMS

An invasive form of intestinal Entamoeba (E.) histolytica infection, which causes amoebic liver abscess, is more common in men than in women. Immunopathological mechanisms are responsible for the more severe outcome in males. Here, we used a mouse model of hepatic amoebiasis to investigate the contribution of hepatic hypoxia-inducible factor (HIF)-1α to T helper 17 (Th17)/regulatory T cell (Treg) responses in the context of the sex-specific outcome of liver damage.

METHODS

C57BL/6J mice were infected intrahepatically with E. histolytica trophozoites. HIF-1α expression was determined by qPCR, flow cytometry and immunohistochemistry. Tregs and Th17 cells were analysed by immunohistochemistry and flow cytometry. Finally, male and female hepatocyte-specific Hif1α knockout mice were generated, and the effect of HIF-1α on abscess development, the cytokine milieu, and Th17/Treg differentiation was examined.

RESULTS

E. histolytica infection increased hepatic HIF-1α levels, along with the elevated frequencies of hepatic Th17 and Treg cells. While the Th17 cell population was larger in male mice, Tregs characterised by increased expression of Foxp3 in female mice. Male mice displayed increased IL-6 expression, contributing to immunopathology; this increase in IL-6 expression declined upon deletion of hepatic HIF-1α. In both sexes, hepatic deletion of HIF-1α reduced the Th17 cell frequency; however, the percentage of Tregs was reduced in female mice only.

CONCLUSIONS

Hepatic HIF-1α modulates the sex-specific outcome of murine E. histolytica infection. Our results suggest that in male mice, Th17 cells can be modulated by hepatic HIF-1α via IL-6, indicating marked involvement in the immunopathology underlying abscess development. Strong expression of Foxp3 by hepatic Tregs from female mice suggests a potent immunosuppressive function, leading to initiation of liver regeneration.

LAY SUMMARY

Infection with the parasite Entamoeba histolytica activates immunopathological mechanisms in male mice, which lead to liver abscesses that are larger than those in female mice. In the absence of the protein HIF-1α in hepatocytes, abscess formation is reduced; moreover, the sex difference in abscess size is abolished. These results suggest that HIF-1α modulates the immune response involved in the induction of immunopathology, resulting in differential disease susceptibility in males and females.

Interleukin-6 as surrogate marker for imaging-based hypoxia dynamics in patients with head-and-neck cancers undergoing definitive chemoradiation-results from a prospective pilot trial

Purpose

Intratumoral hypoxia increases resistance of head-and-neck squamous cell carcinoma (HNSCC) to radiotherapy. [¹⁸F]FMISO PET imaging enables noninvasive hypoxia monitoring, though requiring complex logistical efforts. We investigated the role of plasma interleukin-6 (IL-6) as potential surrogate parameter for intratumoral hypoxia in HNSCC using [¹⁸F]FMISO PET/CT as reference.

Methods

Within a prospective trial, serial blood samples of 27 HNSCC patients undergoing definitive chemoradiation were collected to analyze plasma IL-6 levels. Intratumoral hypoxia was assessed in treatment weeks 0, 2, and 5 using [¹⁸F]FMISO PET/CT imaging. The association between PET-based hypoxia and IL-6 was examined using Pearson’s correlation and multiple regression analyses, and the diagnostic power of IL-6 for tumor hypoxia response prediction was determined with receiver-operating characteristic analyses.

Results

Mean IL-6 concentrations were 15.1, 19.6, and 31.0 pg/mL at baseline, week 2 and week 5, respectively. Smoking (p=0.050) and reduced performance status (p=0.011) resulted in higher IL-6 levels, whereas tumor (p=0.427) and nodal stages (p=0.334), tumor localization (p=0.439), and HPV status (p=0.294) had no influence. IL-6 levels strongly correlated with the intratumoral hypoxic subvolume during treatment (baseline: r=0.775, p<0.001; week 2: r=0.553, p=0.007; week 5: r=0.734, p<0.001). IL-6 levels in week 2 were higher in patients with absent early tumor hypoxia response (p=0.016) and predicted early hypoxia response (AUC=0.822, p=0.031). Increased IL-6 levels at week 5 resulted in a trend towards reduced progression-free survival (p=0.078) and overall survival (p=0.013).

Conclusion

Plasma IL-6 is a promising surrogate marker for tumor hypoxia dynamics in HNSCC patients and may facilitate hypoxia-directed personalized radiotherapy concepts.

Trial registration

The prospective trial was registered in the German Clinical Trial Register (DRKS00003830). Registered 20 August 2015

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05602-x.

Inflammatory mediators in diabetic retinopathy: Deriving clinicopathological correlations for potential targeted therapy

The role of inflammation in diabetic retinopathy (DR) is well-established and dysregulation of a large number of inflammatory mediators is known. These include cytokines, chemokines, growth factors, mediators of proteogenesis, and pro-apoptotic molecules. This para-inflammation as a response is not directed to a particular pathogen or antigen but is rather directed toward the by-products of the diabetic milieu. The inflammatory mediators take part in cascades that result in cellular level responses like neurodegeneration, pericyte loss, leakage, capillary drop out, neovascularization, etc. There are multiple overlaps between the inflammatory pathways occurring within the diabetic retina due to a large number of mediators, their varied sources, and cross-interactions. This makes understanding the role of inflammation in clinical manifestations of DR difficult. Currently, mediator-based therapy for DR is being evaluated for interventions that target a specific step of the inflammatory cascade. We reviewed the role of inflammation in DR and derived a simplified clinicopathological correlation between the sources and stimuli of inflammation, the inflammatory mediators and pathways, and the clinical manifestations of DR. By doing so, we deliberate mediator-specific therapy for DR. The cross-interactions between inflammatory mediators and the molecular cycles influencing the inflammatory cascades are crucial challenges to such an approach. Future research should be directed to assess the feasibility of the pathology-based therapy for DR.

Involvement of Cytokines in the Pathogenesis of Diabetic Macular Edema

Diabetic macular edema (DME) is a critical complication of diabetic retinopathy, a condition that arises from the breakdown of the blood–retinal barrier and the consequent increase in vascular permeability. Over the years, attempts have been made to treat DME by various approaches, including laser photocoagulation, steroid triamcinolone acetonide, and vitrectomy. However, treatment was unsatisfactory until research identified vascular endothelial growth factor (VEGF) as a factor in the pathogenesis of DME. Intraocular anti-VEGF agents show good efficacy in DME. Nevertheless, in some patients the condition recurs or becomes resistant to treatment, suggesting that other factors may be involved. Because inflammation and retinal hypoxia are seen in DME, research has examined the potential role of cytokines and other inflammatory mediators. In this review, we provide an overview of this research and describe feedback mechanisms that may represent a target for novel treatments.

Cytokines and Pathogenesis of Central Retinal Vein Occlusion

Central retinal vein occlusion (CRVO) causes macular edema and subsequent vision loss and is common in people with diseases such as arteriosclerosis and hypertension. Various treatments for CRVO-associated macular edema have been trialed, including laser photocoagulation, with unsatisfactory results. However, when the important pathogenic role of vascular endothelial growth factor (VEGF) in macular edema was identified, the treatment of CRVO was revolutionized by anti-VEGF therapy. However, despite the success of intraocular injection of anti-VEGF agents in many patients with CRVO, some patients continue to suffer from refractory or recurring edema. In addition, the expression of inflammatory cytokines increases over time, causing more severe inflammation and a condition that is increasingly resistant to anti-VEGF therapy. This indicates that the pathogenesis of macular edema in CRVO is more complex than originally thought and may involve factors or cytokines associated with inflammation and ischemia other than VEGF. CRVO is also associated with leukocyte abnormalities and a gradual reduction in retinal blood flow velocity, which increase the likelihood of it developing from the nonischemic type into the more severe ischemic type; in turn, this results in excessive VEGF expression and subsequent neovascular glaucoma. Here, we review the role of different factors and cytokines involved in CRVO pathogenesis and propose a mechanism that holds promise for the development of novel therapies.

Potential Immunotherapeutic Targets for Hypoxia Due to COVI-Flu

The world is currently embroiled in a pandemic of coronavirus disease 2019 (COVID-19), a respiratory illness caused by the novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The severity of COVID-19 disease ranges from asymptomatic to fatal acute respiratory distress syndrome. In few patients, the disease undergoes phenotypic differentiation between 7 and 14 days of acute illness, either resulting in full recovery or symptom escalation. However, the mechanism of such variation is not clear, but the facts suggest that patient's immune status, comorbidities, and the systemic effects of the viral infection (potentially depending on the SARS-CoV-2 strain involved) play a key role. Subsequently, patients with the most severe symptoms tend to have poor outcomes, manifest severe hypoxia, and possess elevated levels of pro-inflammatory cytokines (including IL-1β, IL-6, IFN-γ, and TNF-α) along with elevated levels of the anti-inflammatory cytokine IL-10, marked lymphopenia, and elevated neutrophil-to-lymphocyte ratios. Based on the available evidence, we propose a mechanism wherein SARS-CoV-2 infection induces direct organ damage while also fueling an IL-6-mediated cytokine release syndrome (CRS) and hypoxia, resulting in escalating systemic inflammation, multi-organ damage, and end-organ failure. Elevated IL-6 and hypoxia together predisposes patients to pulmonary hypertension, and the presence of asymptomatic hypoxia in COVID-19 further compounds this problem. Due to the similar downstream mediators, we discuss the potential synergistic effects and systemic ramifications of SARS-CoV-2 and influenza virus during co-infection, a phenomenon we have termed "COVI-Flu." Additionally, the differences between CRS and cytokine storm are highlighted. Finally, novel management approaches, clinical trials, and therapeutic strategies toward both SARS-CoV-2 and COVI-Flu infection are discussed, highlighting host response optimization and systemic inflammation reduction.

Cytokine and Growth Factor Response in a Rat Model of Radiation Induced Injury to the Submental Muscles

Submental muscles (i.e., mylohyoid and geniohyoid) play a vital role during swallowing, protecting the airway from ingested material. To design therapies to reduce the functional deficits associated with radiation treatment relies in part on our understanding of the changes in the cytokine and growth factor response that can impact muscle function. The purpose of this study is to quantify changes in the inflammatory, pro-fibrotic, and pro-angiogenic factors following 48 Gy of fractionated radiation to the mylohyoid muscle. We hypothesized that (1) irradiation will provoke increases in TGF-1β and MMP-2 mRNA in the mylohyoid muscle; and (2) muscles surrounding the target location (i.e., geniohyoid and digastric muscles) will exhibit similar alterations in their gene expression profiles. Rats were exposed to 6 fractions of 8 Gy using a 6 MeV electron beam on a clinical linear accelerator. The highest dose curve was focused at the mylohyoid muscle. After 2- and 4-weeks post-radiation, the mylohyoid, geniohyoid, and digastric muscles were harvested. Expression of TNF-α, IFNγ, IL-1β, IL-6, TGF-1β, VEGF, MMP-2, and MMP-9 mRNA was analyzed via PCR and/or RT-PCR. TGF-1β, MMP-2, and IL-6 expression was upregulated in the irradiated mylohyoid compared to non-irradiated controls. No notable changes in TNF-α, IFNγ, and IL-1β mRNA expression were observed in irradiated muscles. Differing expression profiles were found in the surrounding muscles post-radiation. Results demonstrated that irradiation provokes molecular signals involved in the regulation of wound healing, which could lead to fibrosis or atrophy in the swallowing muscle after radiation.

Cancer cachexia has many symptoms but only one cause: anoxia

During nearly 100 years of research on cancer cachexia (CC), science has been reciting the same mantra: it is a multifactorial syndrome. The aim of this paper is to show that the symptoms are many, but they have a single cause: anoxia. CC is a complex and devastating condition that affects a high proportion of advanced cancer patients. Unfortunately, it cannot be reversed by traditional nutritional support and it generally reduces survival time. It is characterized by significant weight loss, mainly from fat deposits and skeletal muscles. The occurrence of cachexia in cancer patients is usually a late phenomenon. The conundrum is why do similar patients with similar tumors, develop cachexia and others do not? Even if cachexia is mainly a metabolic dysfunction, there are other issues involved such as the activation of inflammatory responses and crosstalk between different cell types.  The exact mechanism leading to a wasting syndrome is not known, however there are some factors that are surely involved, such as anorexia with lower calorie intake, increased glycolytic flux, gluconeogenesis, increased lipolysis and severe tumor hypoxia. Based on this incomplete knowledge we put together a scheme explaining the molecular mechanisms behind cancer cachexia, and surprisingly, there is one cause that explains all of its characteristics: anoxia.  With this different view of CC we propose a treatment based on the physiopathology that leads from anoxia to the symptoms of CC.  The fundamentals of this hypothesis are based on the idea that CC is the result of anoxia causing intracellular lactic acidosis. This is a dangerous situation for cell survival which can be solved by activating energy consuming gluconeogenesis. The process is conducted by the hypoxia inducible factor-1α. This hypothesis was built by putting together pieces of evidence produced by authors working on related topics.

CD154 Induces Interleukin-6 Secretion by Kidney Tubular Epithelial Cells under Hypoxic Conditions: Inhibition by Chloroquine

Inflammation is a major contributor to tubular epithelium injury in kidney disorders, and the involvement of blood platelets in driving inflammation is increasingly stressed. CD154, the ligand of CD40, is one of the mediators supporting platelet proinflammatory properties. Although hypoxia is an essential constituent of the inflammatory reaction, if and how platelets and CD154 regulate inflammation in hypoxic conditions remain unclear. Here, we studied the control by CD154 of the proinflammatory cytokine interleukin- (IL-) 6 secretion in short-term oxygen (O₂) deprivation conditions, using the HK-2 cell line as a kidney tubular epithelial cell (TEC) model. IL-6 secretion was markedly stimulated by CD154 after 1 to 3 hours of hypoxic stress. Both intracellular IL-6 expression and secretion were stimulated by CD154 and associated with a strong upregulation of IL-6 mRNA and increased transcription. Searching for inhibitors of CD154-mediated IL-6 production by HK-2 cells in hypoxic conditions, we observed that chloroquine, a drug that has been repurposed as an anti-inflammatory agent, alleviated this induction. Therefore, CD154 is a potent early stimulus for IL-6 secretion by TECs in O₂ deprivation conditions, a mechanism likely to take part in the deleterious inflammatory consequences of platelet activation in kidney tubular injury. The inhibition of CD154-induced IL-6 production by chloroquine suggests the potential usefulness of this drug as a therapeutic adjunct in conditions associated with acute kidney injury.

Cell Autonomous and Non-cell Autonomous Regulation of SMC Progenitors in Pulmonary Hypertension

Pulmonary hypertension is a devastating disease characterized by excessive vascular muscularization. We previously demonstrated primed platelet-derived growth factor receptor β⁺ (PDGFR-β⁺)/smooth muscle cell (SMC) marker⁺ progenitors at the muscular-unmuscular arteriole border in the normal lung, and in hypoxia-induced pulmonary hypertension, a single primed cell migrates distally and expands clonally, giving rise to most of the pathological smooth muscle coating of small arterioles. Little is known regarding the molecular mechanisms underlying this process. Herein, we show that primed cell expression of Kruppel-like factor 4 and hypoxia-inducible factor 1-α(HIF1-α) are required, respectively, for distal migration and smooth muscle expansion in a sequential manner. In addition, the HIF1-α/PDGF-B axis in endothelial cells non-cell autonomously regulates primed cell induction, proliferation, and differentiation. Finally, myeloid cells transdifferentiate into or fuse with distal arteriole SMCs during hypoxia, and Pdgfb deletion in myeloid cells attenuates pathological muscularization. Thus, primed cell autonomous and non-cell autonomous pathways are attractive therapeutic targets for pulmonary hypertension.

Eccentric exercise results in a prolonged increase in interleukin-6 and tumor necrosis factor-α levels in rat skeletal muscle

Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) are well-known cytokines with pro-inflammatory capabilities, and have been shown to be involved in adaptation to exercise as multifaceted myokines. However, the precise role of IL-6 and TNF-α during exercise-induced skeletal muscle injury and subsequent repair processes is not fully understood. In this study, IL-6 and TNF-α were examined in soleus muscles at the gene and protein levels using in situ hybridization and immunohistochemical staining, respectively, and serum levels of IL-6 and TNF-α were determined before and after a 90-min downhill running session in rats. There were no changes in serum levels of IL-6 and TNF-α after exercise, but IL-6 and TNF-α mRNA increased and maintained high expression in muscles for 1-2 weeks after exercise. IL-6 and TNF-a mRNAs were identified in both the cytoplasm and the nuclei of myocytes, as well as in invading inflammatory cells. IL-6 and TNF-α protein mainly distributed in cytoplasm unevenly and had a prolonged expression until 2 weeks after eccentric exercise. Our results demonstrate that there is increased IL-6 and TNF-α expression in skeletal muscle that is induced by eccentric exercise and that the high expression of IL-6 and TNF-α in the long-term phase after eccentric exercise may be more involved in the subsequent recovery of damaged muscle.

Cell-specific image-guided transcriptomics identifies complex injuries caused by ischemic acute kidney injury in mice

The kidney's inherent complexity has made identifying cell-specific pathways challenging, particularly when temporally associating them with the dynamic pathophysiology of acute kidney injury (AKI). Here, we combine renal cell-specific luciferase reporter mice using a chemoselective luciferin to guide the acquisition of cell-specific transcriptional changes in C57BL/6 background mice. Hydrogen peroxide generation, a common mechanism of tissue damage, was tracked using a peroxy-caged-luciferin to identify optimum time points for immunoprecipitation of labeled ribosomes for RNA-sequencing. Together, these tools revealed a profound impact of AKI on mitochondrial pathways in the collecting duct. In fact, targeting the mitochondria with an antioxidant, ameliorated not only hydrogen peroxide generation, but also significantly reduced oxidative stress and the expression of the AKI biomarker, LCN2. This integrative approach of coupling physiological imaging with transcriptomics and drug testing revealed how the collecting duct responds to AKI and opens new venues for cell-specific predictive monitoring and treatment.

The influence of capillarization on satellite cell pool expansion and activation following exercise-induced muscle damage in healthy young men

KEY POINTS

Skeletal muscle stem cells (satellite cells) play a crucial role in repair and remodelling of muscle in response to exercise. Satellite cells are in close spatial proximity to muscle capillaries and therefore may be influenced by them. In this study, we describe the activation and expansion of the satellite cell pool in response to eccentric contraction-induced muscle damage in individuals with significantly different levels of muscle capillarization. Individuals with greater capillarization and capacity for muscle perfusion demonstrated enhanced activation and/or expansion of the satellite cell pool allowing for an accelerated recovery of muscle function. These results provide insight into the critical relationship between muscle capillarization and satellite cells during skeletal muscle repair.

ABSTRACT

Factors that determine the skeletal muscle satellite cell (SC) response remain incompletely understood. It is known, however, that SC activation status is closely related to the anatomical relationship between SCs and muscle capillaries. We investigated the impact of muscle fibre capillarization on the expansion and activation status of SCs following a muscle-damaging exercise protocol in healthy young men. Twenty-nine young men (21 ± 0.5 years) performed 300 unilateral eccentric contractions (180 deg s^-1 ) of the knee extensors. Percutaneous muscle biopsies from the vastus lateralis and blood samples from the antecubital vein were taken prior to (Pre) exercise and at 6, 24, 72 and 96 h of post-exercise recovery. A comparison was made between subjects who had a relative low mixed muscle capillary-to-fibre perimeter exchange index (CFPE; Low group) and high mixed muscle CFPE index (High group) at baseline. Type I and type II muscle fibre size, myonuclear content, capillarization, and SC response were determined via immunohistochemistry. Overall, there was a significant correlation (r = 0.39; P < 0.05) between the expansion of SC content (change in total Pax7⁺ cells/100 myofibres) 24 h following eccentric exercise and mixed muscle CFPE index. There was a greater increase in activated SCs (MyoD⁺ /Pax7⁺ cells) in the High as compared to the Low CFPE group 72 h following eccentric exercise (P < 0.05). The current study provides further evidence that muscle fibre capillarization may play an important role in the activation and expansion of the SC pool during the process of skeletal muscle repair.

Genome-wide analysis sheds light on the high-altitude adaptation of the buff-throated partridge (Tetraophasis szechenyii)

The buff-throated partridge (Tetraophasis szechenyii) is a hypoxia-tolerant bird living in an extremely inhospitable high-altitude environment, which has high ultraviolet (UV) radiation as well as a low oxygen supply when compared with low-altitude areas. To further understand the molecular genetic mechanisms of the high-altitude adaptation of the buff-throated partridges, we de novo assembled the complete genome of the buff-throated partridge. Comparative genomics revealed that positively selected hypoxia-related genes in the buff-throated partridge were distributed in the HIF-1 signaling pathway (map04066), response to hypoxia (GO:0001666), response to oxygen-containing compound (GO:1901700), ATP binding (GO:0005524), and angiogenesis (GO:0001525). Of these positively selected hypoxia-related genes, one positively selected gene (LONP1) had one buff-throated partridge-specific missense mutation which was classified as deleterious by PolyPhen-2. Moreover, positively selected genes in the buff-throated partridge were enriched in cellular response to DNA damage stimulus (corrected P value: 0.028006) and DNA repair (corrected P value: 0.044549), which was related to the increased exposure of the buff-throated partridge to UV radiation. Compared with other avian genomes, the buff-throated partridge showed expansion in genes associated with steroid hormone receptor activity and contractions in genes related to immune and olfactory perception. Furthermore, comparisons between the buff-throated partridge genome and red junglefowl genome revealed a conserved genome structure and provided strong evidence of the sibling relationship between Tetraophasis and Lophophorus. Our data and analysis contributed to the study of Phasianidae evolutionary history and provided new insights into the potential adaptation mechanisms to the high altitude employed by the buff-throated partridge.

Association of Cyclooxygenase-2 Immunoreactivity with Tumor Recurrence and Disease Progression in Superficial Urothelial Bladder Cancer

Aims and Background

The main characteristic of urothelial bladder cancer is a clear predisposition to recurrence and disease progression. The aim of this study was to assess the possible relationship between cyclooxygenase-2 (COX-2) immunoreactivity in superficial urothelial bladder carcinoma and tumor grade, stage, number of recurrences and clinical disease progression.

Methods

In this prospective study 70 consecutive patients who underwent transurethral resection for superficial urothelial bladder cancer were included. Tumor slides were immuno-histochemically stained for COX-2, and COX-2 immunoreactivity in tumor and inflammatory stromal cells was categorized as negative or mildly, moderately or strongly positive. Patients were followed up for 2 years, and during this period the possible association of COX-2 immunoreactivity with tumor stage and grade, number of recurrences and progression of disease was evaluated.

Results

COX-2 immunoreactivity in tumor cells was found in 57 (81.4%) patients and did not correlate with tumor grade, stage of disease, number of recurrences, and progression of disease. COX-2 immunoreactivity in inflammatory cells was found in 16 of the 57 patients with COX-2 positive tumors, and was significantly related to the number of recurrences, time to appearance of the first recurrence, and disease progression.

Conclusions

COX-2 immunoreactivity in inflammatory stromal cells adjacent to the COX-2-positive tumor might be useful in clinical practice for selection of patients with a high risk of tumor recurrence and disease progression.

Acid-Base and Electrolyte Changes Drive Early Pathology in Ischemic Stroke

Emergent large vessel occlusion accounts for 20-40% of ischemic strokes and is the most debilitating form of stroke. Some of the earliest changes in response to ischemic stroke occur in blood gases and electrolytes. These biochemical changes occur within minutes after occlusion in experimental models of stroke and can be utilized to predict stroke outcomes. The majority of ELVO stroke patients are middle-aged to elderly and are of both sexes, revealing that there is an age and sex mismatch between ischemic stroke patients and animal models, since most experimental studies use young male rats. Rethinking of the animal models should be considered, especially in encouraging the use of aged male and female rats with comorbidities to more closely mirror human populations. Mechanical thrombectomy provides a unique opportunity for researchers to further this work by expanding the collection and analysis of blood samples that are adjacent to the thrombus. To understand the complexity of stroke, researchers can analyze these tissues for different molecular targets that occur in response to ischemic stroke. This information may aid in the reduction of symptom burden for individuals diagnosed with ischemic stroke. Investigators should also focus on data from ischemic stroke patients and attempt to discover target molecules and then in animal models to establish mechanism, which will aid in the development of new stroke therapies. This review discusses the translation of these studies to the human patient to develop the capability to predict stroke outcomes. Future studies are needed to identify molecular targets to predict the risk of worsened long-term outcomes and/or increased risk for mortality.

Cytokines and the Pathogenesis of Macular Edema in Branch Retinal Vein Occlusion

Branch retinal vein occlusion (BRVO) is a very common retinal vascular problem in patients with lifestyle-related diseases, such as hypertension and arteriosclerosis. In patients with BRVO, development of macular edema is the main cause of visual impairment. BRVO is still a controversial condition in many respects. Over the years, various methods such as laser photocoagulation have been tried to treat macular edema associated with BRVO, but the results were not satisfactory. After vascular endothelial growth factor (VEGF) was found to have an important role in the pathogenesis of macular edema in BRVO patients, treatment of this condition was revolutionized by development of anti-VEGF therapy. Although macular edema improves dramatically following intraocular injection of anti-VEGF agents, repeated recurrence and resistance of edema is a major problem in some BRVO patients. This suggests that factors or cytokines other than VEGF may be associated with inflammation and retinal hypoxia in BRVO and that the pathogenesis of macular edema is complicated. The present review assesses the role of various factors and cytokines in the pathogenesis of macular edema associated with BRVO. We present a mechanism that is not only plausible but should also be useful for developing new therapeutic strategies.

HIF-1α facilitates osteocyte-mediated osteoclastogenesis by activating JAK2/STAT3 pathway in vitro

Osteocytes, entrapped within the mineralized bone matrix, has been found to have numerous functions such as acting as an orchestrator of bone remodeling through regulation of both osteoclast and osteoblast activity and also functioning as an endocrine cell. Due to a specialized morphology and surrounding structure, osteocytes are more tolerant to hypoxia during osteoporosis, fracture, osteoarthritis, and orthodontic-orthognathic combination therapy. Hypoxia-inducible factor-1α (HIF-1α) is one of the master regulators of hypoxia reactions, playing an important role in bone modeling, remodeling, and homeostasis. This study aimed to investigate the pivotal functional role of HIF-1α in osteocytes initiating of bone remodeling under hypoxia. In the present study, the osteoclasts formation induced by RAW264.7 was significantly promoted in conditioned media (CM) from osteocytic MLO-Y4 exposed to hypoxia in vitro. Therefore, hypoxic MLO-Y4 cells simulated by 100 μmol/L CoCl₂ or 2% O₂ stably expressed HIF-1α proteins and upregulated the expression of receptor activator of nuclear factor-κB ligand (RANKL) at both the messenger RNA (mRNA) and protein level. Furthermore, with the Knockdown of HIF-1α, the expression of RANKL mRNA and protein decreased after transient transfection. In addition, the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription (STAT3) was also correlated with HIF-1α and RANKL levels under hypoxia. Then AG490, a JAK2 inhibitor, inhibited p-JAK2, p-STAT3 and RANKL expression. It was possible that AG490 disturbed the contact of HIF-1α and RANKL by JAK2/STAT3 pathway, influencing osteoclastogenesis. Our findings suggested that HIF-1α promoted the expression of RANKL by activating JAK2/STAT3 pathway in MLO-Y4 cells, and enhanced osteocyte-mediated osteoclastic differentiation in vitro.

Carboranyl Analogues of Celecoxib with Potent Cytostatic Activity against Human Melanoma and Colon Cancer Cell Lines

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most common way of treating inflammatory disorders. Their widespread use helped reveal their other modes of action as pharmaceuticals, such as a profound effect on various cancers. Celecoxib has proven to be a very prominent member of this group with cytostatic activities. On the other hand, the highly dynamic field of drug design is constantly searching for new ways of modifying known structures to obtain more powerful and less harmful drugs. A very interesting development is the implementation of carboranes in pharmacologically active structures, mostly as phenyl mimetics. Herein we report the synthesis of three carborane-containing derivatives of the COX-2-selective NSAID celecoxib. The new compounds proved to have promising cytostatic potential against various melanoma and colorectal adenocarcinoma cell lines. Inhibited proliferation accompanied by caspase-independent apoptotic cell death was found to be the main cause of decreased cell viability upon treatment with the most efficient celecoxib analogue, 3 b (4-[5-(1,7-dicarba-closo-dodecaboranyl)-3-trifluoromethyl-1H-pyrazol-1-yl]-1-methylsulfonylbenzene).

Interleukin-6 and amyotrophic lateral sclerosis

BACKGROUND

IL-6 is an inflammatory cytokine that is a possible factor in progression of the disease. We have investigated venous blood levels of IL-6 in controls and ALS patients in relation to clinical staging and respiratory function.

METHODS

We studied 82 patients with ALS and 43 age and gender-matched healthy control subjects. Blood was drawn at the same time of day in the mornings to avoid diurnal variation. IL-6 levels were estimated according to a fixed protocol. Clinical measures included ALSFRS-R, vital capacity, and mean bilateral phrenic nerve CMAP amplitude. A multi-regression data analysis was used in addition to conventional statistical methods.

RESULTS

IL-6 levels were positively correlated with increasing age in the control group. In ALS patients mean IL-6 levels were raised but the levels were markedly variable from case to case and did not reach significance (p 0.1). In addition to age effects reduction in phrenic nerve CMAP amplitude was correlated with increased IL-6 levels (p 0.026).

CONCLUSIONS

IL-6 levels were physiologically influenced by aging in controls and by respiratory dysfunction in ALS. There was marked variability in levels from case to case, which might be related to respiratory factors, which cause pulmonary inflammation.

New role of hypoxia in pathophysiology of multiple myeloma through miR-210

Bone is one of the most common sites of complication in multiple myeloma (MM) progression and bone remodeling gets definitively perturbed during disease progression. Hypoxia and miR-210 play an important role in hematological malignancies. In an attempt to elucidate the specificity of the pathways of hypoxia and miR-210 in suppression of osteoblastic differentiation in MM patients, we examined the effect of miR-210 and hypoxia on expression of important cytokines and genes of myeloma cells. Differentiation of BM-MSCs towards osteoblastic cells in response to microvesicles (MVs) was also investigated. Finally, we proposed a molecular model on how HIF-1α may promote bone lesions in MM patients. To validate the effect of miR-210 and HIF-1α on targeted genes, the shRNA of HIF-1α and off-hsa-miR-210 were transfected into RPMI-8226 cells. BM-MSCs were cultured in osteoblastic inducer and 50 µg/mL of MVs derived from both hypoxic and normoxic myeloma cells. We designed an in vitro study to establish the effects of HIF-1α and miR-210 on the crosstalk between MM and osteoblasts. We here showed that hypoxia-induced miR-210 increased the mRNA expression of VLA-4, CXCR4, IL-6 and TGF-β in myeloma cells. MiR-210 is mandatory for the hypoxia-increased resistance of MM cells to melphalan. Moreover, MVs derived from hypoxic myeloma cells substantially decreased osteoblast differentiation. Considered comprehensively, our findings explain one of the reasons of bone loss that occurs at the sites of MM and a nascent crosstalk model in MM pathogenesis.

Gas6 protein induces invasion and reduces inflammatory cytokines in oral squamous cell carcinoma

BACKGROUND

Gas6 protein is involved in the progression of cancers and has been demonstrated to have a role in inflammation. Oral squamous cell carcinoma is a common form of oral cancer, and it commonly expresses Gas6. Our objective was to determine the effects of Gas6 on oral squamous cell carcinoma invasion and identify signaling molecules and cytokines associated with Gas6-mediated invasion.

METHODS

Ca9-22 cells were cultured in the presence or absence of Gas6. Real-time cell invasion was evaluated, and cultured cells were lysed for Western blot analysis. Cell medium was collected and assayed for cytokine elaboration.

RESULTS

Treatment of cells with Gas6 resulted in: (i) increased invasion, (ii) increased expression of Gas6 and AXL receptor, (iii) reduced invasion when AXL was inhibited, (iv) decreased ERK activation, (v) increased AKT activation, and (vi) decreased secretion of G-CSF, IL-2, IL-6, and IL-8.

CONCLUSIONS

Gas6 increases invasion of oral squamous cell carcinoma, and the invasion correlates with the increased AKT and the downregulation of pro-inflammatory cytokines. These results may prove useful in providing avenues that explain the role of Gas6 in the development and progression of oral squamous cell carcinoma.

Remote ischemic preconditioning STAT3-dependently ameliorates pulmonary ischemia/reperfusion injury

The lungs are highly susceptible to injury, including ischemia/reperfusion (I/R) injury. Pulmonary I/R injury can occur when correcting conditions such as primary pulmonary hypertension, and is also relatively common after lung transplantation or other cardiothoracic surgery. Methods to reduce pulmonary I/R injury are urgently needed to improve outcomes following procedures such as lung transplantation. Remote liver ischemic preconditioning (RLIPC) is an effective cardioprotective measure, reducing damage caused by subsequent cardiac I/R injury, but little is known about its potential role in pulmonary protection. Here, we analyzed the efficacy and mechanistic basis of RLIPC in a rat model of pulmonary I/R injury. RLIPC reduced lung I/R injury, lessening structural damage, inflammatory cytokine production and apoptosis. In addition, RLIPC preserved pulmonary function compared to controls following lung I/R injury. RLIPC stimulated phosphorylation of pulmonary STAT3, a component of the SAFE signaling pathway, but not phosphorylation of RISK pathway signaling proteins. Accordingly, STAT3 inhibition using AG490 eliminated the pulmonary protection afforded by RLIPC. Our data demonstrate for the first time that RLIPC protects against pulmonary I/R injury, via a signaling pathway requiring STAT3 phosphorylation.

Circulating Angiogenesis Regulators in Cancer Patients

Background/Aims

To date, numerous studies have demonstrated that several angiogenesis regulators circulate in the blood and may function as endocrine factors in cancer patients. This review aims to give a comprehensive insight into the possible clinical value of circulating angiogenesis regulators, mainly basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and hepatocyte growth factor (HGF), angiogenin, pleiotrophin, thrombospondin (TSP) and endostatin (ES) in cancer patients.

Methods

A computerized (MEDLINE) and a manual search based on the reference lists of the publications were performed to identify articles published on this topic.

Results

In a detailed literature search, approximately 100 publications were found up to the end of 1999. Circulating angiogenic factors such as bFGF, VEGF, HGF and angiogenin have been evaluated not only as diagnostic and/or prognostic factors but also as predictive factors in cancer patients. On the other hand, little is known about the clinical significance of negative regulators. Neither the source nor the mechanism of protein externalization has been clarified in detail.

Conclusions

Although there are no known factors with established clinical utility, circulating angiogenesis regulators may be useful in several situations. They could be used to determine the risk of developing cancer, to screen for early detection, to distinguish benign from malignant disease, and to distinguish between different types of malignancies. In patients with established malignancies such factors might be used to determine prognosis, to predict the response to therapy, and to monitor the clinical course. Further investigations are warranted to assess the specific utility of each factor.

Peritoneal Fluid Cytokines and the Differential Diagnosis of Benign and Malignant Ovarian Tumors and Residual/Recurrent Disease Examination

This study aimed to assess the potential value of peritoneal fluid cytokine examination for the differential diagnosis of ovarian tumors and for evaluating residual or recurrent disease after treatment. The cytokines that are commonly elevated in ovarian cancer, VEGF, IL-6, bFGF, IL-8 and M-CSF, and a reference ovarian tumor marker, CA 125, were measured in peritoneal fluids of 53 previously untreated patients with epithelial ovarian cancer, 18 ovarian cancer patients after surgical treatment and chemotherapy, and 17 patients with benign epithelial ovarian tumors. Non-parametric statistical analysis of data was performed. Ovarian cancer peritoneal fluids, as compared to peritoneal fluids of patients with benign ovarian tumors, contained significantly higher concentrations of IL-6, VEGF and CA 125, and significantly lower concentrations of bFGF and M-CSF, but only the levels of IL-6 and VEGF were significantly higher in peritoneal fluids of stage I and II ovarian cancer patients than of patients with benign ovarian conditions. IL-6 at the cutoff level of 400 pg/mL discriminated benign and malignant ovarian tumors with 92% sensitivity and 60% specificity, while VEGF at the cutoff of 400 pg/mL had 90% sensitivity and 80% specificity. At the cutoff level of 1200 pg/mL, IL-6 had 84% sensitivity and 87% specificity. A radical decrease in local cytokine and CA 125 levels in patients after treatment was independent of therapy outcome.

IL-6 and VEGF measurements in peritoneal fluids might be useful for the differential diagnosis of malignant and benign ovarian conditions, but not for residual or recurrent disease examination.

Cellular and Oxidative Mechanisms Associated with Interleukin-6 Signaling in the Vasculature

Reactive oxygen species, particularly superoxide, promote endothelial dysfunction and alterations in vascular structure. It is increasingly recognized that inflammatory cytokines, such as interleukin-6 (IL-6), contribute to endothelial dysfunction and vascular hypertrophy and fibrosis. IL-6 is increased in a number of cardiovascular diseases, including hypertension. IL-6 is also associated with a higher incidence of future cardiovascular events and all-cause mortality. Both immune and vascular cells produce IL-6 in response to a number of stimuli, such as angiotensin II. The vasculature is responsive to IL-6 produced from vascular and non-vascular sources via classical IL-6 signaling involving a membrane-bound IL-6 receptor (IL-6R) and membrane-bound gp130 via Jak/STAT as well as SHP2-dependent signaling pathways. IL-6 signaling is unique because it can also occur via a soluble IL-6 receptor (sIL-6R) which allows for IL-6 signaling in tissues that do not normally express IL-6R through a process referred to as IL-6 trans-signaling. IL-6 signaling mediates a vast array of effects in the vascular wall, including endothelial activation, vascular permeability, immune cell recruitment, endothelial dysfunction, as well as vascular hypertrophy and fibrosis. Many of the effects of IL-6 on vascular function and structure are representative of loss or reductions in nitric oxide (NO) bioavailability. IL-6 has direct effects on endothelial nitric oxide synthase activity and expression as well as increasing vascular superoxide, which rapidly inactivates NO thereby limiting NO bioavailability. The goal of this review is to highlight both the cellular and oxidative mechanisms associated with IL-6-signaling in the vascular wall in general, in hypertension, and in response to angiotensin II.

The meta-analytical paradigm in an in silico hybrid: Pathways and networks perturbed during exposure to varying degrees of hypobaric hypoxia

PURPOSE

Computational biology has opened a gateway to omics data analysis and shifted the focus from molecules to systemic molecular networks in the domain of hypobaric hypoxia (HH). Yet there are no meta-analytical investigations circumventing constraints such as organism (rat/human), HH exposure conditions (acute/chronic), and the tissues that can be investigated simultaneously in the realm of wet lab experiments.

EXPERIMENTAL DESIGN

We analyzed 154 differentially expressed proteins upon HH exposure using Ingenuity Pathway Analysis (IPA) tool, without the constraint of using a single organism or tissue type, to determine the most significant pathways and networks that are perturbed across a range of HH conditions.

RESULTS

We found acute phase response signaling, farsenoid X receptor/retinoid X receptor activation, liver X receptor/retinoid X receptor activation, clathrin-mediated endocytosis signaling, mitochondrial dysfunction, production of nitric oxide and ROS in macrophages, and integrin signaling to be the most significant universally perturbed pathways. Unique protein-function relationships have also been highlighted.

CONCLUSION AND CLINICAL RELEVANCE

This meta-analysis provides a list of specific pathways and networks across two model organisms that are perturbed due to HH exposure irrespective of its duration/intensity. Thus, it will be a map of important pathways and proteins to look at when exploring effects of HH exposure irrespective of tissue/organism chosen, particularly in the context of prophylactic/therapeutic targets.

Inflammatory Cytokine Levels After Endovascular Therapy in Patients With Peripheral Artery Disease

We evaluated the impact of endovascular therapy (EVT) on inflammatory cytokine levels and its relationship with in-stent restenosis in patients with peripheral artery disease. The study prospectively enrolled 35 patients with intermittent claudication who underwent EVT of the iliofemoral artery. Levels of interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor α (TNF-α) were measured using enzyme-linked immunosorbent assay before and at 2 hours, 4 hours, and 3 months after EVT. All cytokine levels increased significantly after EVT (IL-6 [pg/mL]: from 1.51 [0.84-1.93] before EVT to 6.97 [4.05-20.41] at 2 hours and 13.29 [4.57-31.88] at 4 hours; MCP-1 [pg/mL]: from 326.65 [265.60-406.55] before EVT to 411.18 [341.21-566.27] at 2 hours and 519.36 [383.58-644.85] at 4 hours; TNF-α [pg/mL]: from 1.08 [0.77-1.29] before EVT to 1.25 [0.94-1.81] at 2 hours and 1.27 [0.95-1.59] at 4 hours, all P < .001). However, cytokine levels did not differ significantly between lesions with and without in-stent restenosis. Overall, our results suggest that EVT significantly increases IL-6, MCP-1, and TNF-α levels in the ischemic leg, but this effect is not associated with a higher rate of in-stent restenosis.

Altered muscle satellite cell activation following 16 wk of resistance training in young men

Skeletal muscle satellite cells (SC) play an important role in muscle adaptation. In untrained individuals, SC content and activation status have been observed to increase in response to a single bout of exercise. Muscle fiber characteristics change considerably when resistance exercise is performed chronically, but whether training status affects the activity of SC in response to a single bout of exercise remains unknown. We examined the changes in SC content and activation status following a single bout of resistance exercise, before and following a 16-wk progressive resistance training (RT) program in 14 young (25 ± 3 yr) men. Before and after RT, percutaneous biopsies from the vastus lateralis muscle were taken before a single bout of resistance exercise and after 24 and 72 h of postexercise recovery. Muscle fiber size, capillarization, and SC response were determined by immunohistochemistry. Following RT, there was a greater activation of SC after 24 h in response to a single bout of resistance exercise (Pre, 1.4 ± 0.3; 24 h, 3.1 ± 0.3 Pax7⁺/MyoD⁺ cells per 100 fibers) compared with before RT (Pre, 1.4 ± 0.3; 24 h, 2.2 ± 0.3 Pax7⁺/MyoD⁺ cells per 100 fibers, P < 0.05); no difference was observed 72 h postexercise. Following 16 wk of RT, MyoD mRNA expression increased from basal to 24 h after the single bout of exercise (P < 0.05); this change was not observed before training. Individual capillary-to-fiber ratio (C/Fi) increased in both type I (1.8 ± 0.3 to 2.0 ± 0.3 C/Fi, P < 0.05) and type II (1.7 ± 0.3 to 2.2 ± 0.3 C/Fi, P < 0.05) fibers in response to RT. After RT, enhanced activation of SC in response to resistance exercise is accompanied by increases in muscle fiber capillarization.

HIF1α-induced PDGFRβ signaling promotes developmental HSC production via IL-6 activation

Hematopoietic stem cells (HSCs) have the ability to both self-renew and differentiate each of the mature blood cell lineages and thereby reconstitute the entire blood system. Therefore, HSCs are therapeutically valuable for treatment of hematological malignances and bone marrow failure. We showed recently that transient glucose elevation elicited dose-dependent effects on HSCs through elevated metabolic activity and subsequent reactive oxygen species-mediated induction of Hypoxia-Inducible Factor 1α (Hif1α). Platelet-Derived Growth Factor B (pdgfb), a Hif1α-target, and its receptor, pdgfrb, were significantly upregulated in response to metabolic stimulation. Although the function of PDGF signaling is well established in vascular development, its role in hematopoiesis is less understood. Exposure to either a pan-PDGF inhibitor or a PDGFRβ-selective antagonist in the context of Hif1α stimulation blocked elevations in hematopoietic stem and progenitor cell (HSPC) formation as determined by runx1;cmyb whole-mount in situ hybridization (WISH) and HSPC-reporter flow cytometry analysis. Similar results were observed for morpholino (MO) knockdown of pdgfrb or dominant-negative pdgfrb expression, indicating that PDGFRβ signaling is a key downstream mediator of Hif1α-mediated induction of HSPCs. Notably, overexpression of Pdgfb ligand enhanced HSPC numbers in the aorta-gonado-mesonephros (AGM) at 36 hours postfertilization (hpf) and in the caudal hematopoietic tissue at 48 hpf. A survey of known PDGF-B/PDGFRβ regulatory targets by expression analysis revealed a significant increase in inflammatory intermediates, including Interleukin 6 (IL-6) and its receptor (IL-6R). MO-mediated knockdown of il6 or chemical inhibition of IL-6R antagonized the effect of Pdgfb overexpression. Furthermore, epistatic analysis of IL-6/IL-6R function confirmed activity downstream of Hif1α. Together, these findings define a Hif1α-regulated signaling axis mediated through PBFGB/PDGFRβ and IL-6/IL-6R that acts to control embryonic HSPC production.

Klebsiella pneumoniae Siderophores Induce Inflammation, Bacterial Dissemination, and HIF-1α Stabilization during Pneumonia

Klebsiella pneumoniae is a Gram-negative pathogen responsible for a wide range of infections, including pneumonia and bacteremia, and is rapidly acquiring antibiotic resistance. K. pneumoniae requires secretion of siderophores, low-molecular-weight, high-affinity iron chelators, for bacterial replication and full virulence. The specific combination of siderophores secreted by K. pneumoniae during infection can impact tissue localization, systemic dissemination, and host survival. However, the effect of these potent iron chelators on the host during infection is unknown. In vitro, siderophores deplete epithelial cell iron, induce cytokine secretion, and activate the master transcription factor hypoxia inducible factor-1α (HIF-1α) protein that controls vascular permeability and inflammatory gene expression. Therefore, we hypothesized that siderophore secretion by K. pneumoniae directly contributes to inflammation and bacterial dissemination during pneumonia. To examine the effects of siderophore secretion independently of bacterial growth, we performed infections with tonB mutants that persist in vivo but are deficient in siderophore import. Using a murine model of pneumonia, we found that siderophore secretion by K. pneumoniae induces the secretion of interleukin-6 (IL-6), CXCL1, and CXCL2, as well as bacterial dissemination to the spleen, compared to siderophore-negative mutants at an equivalent bacterial number. Furthermore, we determined that siderophore-secreting K. pneumoniae stabilized HIF-1α in vivo and that bacterial dissemination to the spleen required alveolar epithelial HIF-1α. Our results indicate that siderophores act directly on the host to induce inflammatory cytokines and bacterial dissemination and that HIF-1α is a susceptibility factor for bacterial invasion during pneumonia.

Klebsiella pneumoniae causes a wide range of bacterial diseases, including pneumonia, urinary tract infections, and sepsis. To cause infection, K. pneumoniae steals iron from its host by secreting siderophores, small iron-chelating molecules. Classically, siderophores are thought to worsen infections by promoting bacterial growth. In this study, we determined that siderophore-secreting K. pneumoniae causes lung inflammation and bacterial dissemination to the bloodstream independently of bacterial growth. Furthermore, we determined that siderophore-secreting K. pneumoniae activates a host protein, hypoxia inducible factor (HIF)-1α, and requires it for siderophore-dependent bacterial dissemination. Although HIF-1α can protect against some infections, it appears to worsen infection with K. pneumoniae. Together, these results indicate that bacterial siderophores directly alter the host response to pneumonia in addition to providing iron for bacterial growth. Therapies that disrupt production of siderophores could provide a two-pronged attack against K. pneumoniae infection by preventing bacterial growth and preventing bacterial dissemination to the blood.