Chemokine signaling in inflammation

Transcriptome sequencing analysis of bovine mammary epithelial cells induced by lipopolysaccharide

Mastitis in cows is caused by the inflammation of the mammary glands due to an infection by external pathogenic bacteria. Mammary gland epithelial cells, which are in direct contact with the external environment, are responsible for the first line of defense of the mammary gland against pathogenic bacteria, playing an essential role in immune defense. To investigate the mechanism of bovine mammary epithelial cells in the inflammatory process, we treated the cells with LPS for 12 hours and analyzed the changes in mRNA by transcriptome sequencing. The results showed that compared to the control group, the LPS treatment group had 121 up-regulated genes and 18 down-regulated genes. GO and KEGG enrichment analysis revealed that these differential genes were mainly enriched in the IL-17 signaling pathway, Legionellosis, Cytokine-cytokine receptor interaction, NF-kappa B signaling pathway, and other signaling pathways. Furthermore, the expression of GRO1 and CXCL3 mRNAs increased significantly after LPS treatment. These findings provide new insights for the treatment of mastitis in cows in the future.

Imidacloprid-induced lung injury in mice: Activation of the PI3K/AKT/NF-κB signaling pathway via TLR4 receptor engagement

Significant impairment of pulmonary function has been demonstrated through long-term exposure to neonicotinoid insecticides, such as imidacloprid (IMI). However, the underlying mechanisms of lung injury induced by IMI remain unclear. In this study, a mouse model of IMI-induced pulmonary injury was established, and the toxicity and lung damage were assessed through mouse body weight, organ index, hematological parameters, and histopathological analysis of lung tissues. Furthermore, metabolomics and transcriptomics techniques were employed to explore the mechanistic aspects. Results from the toxicity assessments indicated that mouse body weight was significantly reduced by IMI, organ index was disturbed, and hematological parameters were disrupted, resulting in pulmonary injury. The mechanistic experimental results indicate that the differences in metabolites and gene expression in mouse lungs could be altered by IMI. Validation of the results through combined analysis of metabolomics and transcriptomics revealed that the mechanism by which IMI induces lung injury in mice might be associated with the activation of the TLR4 receptor, thereby activating the PI3K/AKT/NF-κB signaling pathway to induce inflammation in mouse lungs. This study provided valuable insights into the mechanisms underlying IMI-induced pulmonary damage, potentially contributing to the development of safer pest control strategies. The knowledge gained served as a robust scientific foundation for the prevention and treatment of IMI-related pulmonary injuries.

Altered immune pathways in patients of temporal lobe epilepsy with and without hippocampal sclerosis

Over the past decades, the immune responses have been suspected of participating in the mechanisms for epilepsy. To assess the immune related pathway in temporal lobe epilepsy (TLE), we explored the altered immune pathways in TLE patients with and without hippocampal sclerosis (HS). We analyzed RNA-seq data from 3 TLE-HS and 3 TLE-nonHS patients, including identification of differentially expressed RNA, function pathway enrichment, the protein-protein interaction network and construction of ceRNA regulatory network. We illustrated the immune related landscape of molecules and pathways on human TLE-HS. Also, we identified several differential immune related genes like HSP90AA1 and SOD1 in TLE-HS patients. Further ceRNA regulatory network analysis found SOX2-OT connected to miR-671-5p and upregulated the target gene SPP1 in TLE-HS patients. Also, we identified both SOX2-OT and SPP1 were significantly upregulated in five different databases including TLE-HS patients and animal models. Our findings established the first immune related genes and possible regulatory pathways in TLE-HS patients and animal models, which provided a novel insight into disease pathogenesis in both patients and animal models. The immune related SOX2-OT/miR-671-5p/SPP1 axis may be the potential therapeutic target for TLE-HS.

Novel molecular mechanism driving neuroprotection after soluble epoxide hydrolase inhibition: Insights for Alzheimer's disease therapeutics

BACKGROUND

Neuroinflammation is widely recognized as a significant hallmark of Alzheimer's disease (AD). To combat neuroinflammation, the inhibition of the soluble epoxide hydrolase (sEH) enzyme has been demonstrated crucial. Importantly, sEH inhibition could be related to other neuroprotective pathways described in AD.

AIMS

The aim of the study was to unveil new molecular pathways driving neuroprotection through sEH, we used an optimized, potent, and selective sEH inhibitor (sEHi, UB-SCG-51).

MATERIALS AND METHODS

UB-SCG-51 was tested in neuroblastoma cell line, SH-SY5Y, in primary mouse and human astrocytes cultures challenged with proinflammatory insults and in microglia cultures treated with amyloid oligomers, as well as in mice AD model (5XFAD).

RESULTS

UB-SCG-51 (10 and 30 μM) prevented neurotoxic reactive-astrocyte conversion in primary mouse astrocytes challenged with TNF-α, IL-1α, and C1q (T/I/C) combination for 24 h. Moreover, in microglial cultures, sEHi reduced inflammation and glial activity. In addition, UB-SCG-51 rescued 5XFAD cognitive impairment, reducing the number of Amyloid-β plaques and Tau hyperphosphorylation accompanied by a reduction in neuroinflammation and apoptotic markers. Notably, a transcriptional profile analysis revealed a new pathway modulated by sEHi treatment. Specifically, the eIF2α/CHOP pathway, which promoted the endoplasmic reticulum response, was increased in the 5XFAD-treated group. These findings were confirmed in human primary astrocytes by combining sEHi and eIF2α inhibitor (eIF2αi) treatment. Besides, combining both treatments resulted in increased in C3 gene expression after T/I/C compared with the group treated with sEHi alone in cultures.

DISCUSSION

Therefore, sEHi rescued cognitive impairment and neurodegeneration in AD mice model, based on the reduction of inflammation and eIF2α/CHOP signaling pathway.

CONCLUSIONS

In whole, our results support the concept that targeting neuroinflammation through sEH inhibition is a promising therapeutic strategy to fight against Alzheimer's disease with additive and/or synergistic activities targeting neuroinflammation and cell stress.

Esaxerenone Protects against Diabetic Cardiomyopathy via Inhibition of the Chemokine and PI3K-Akt Signaling Pathway

(1) Background: Diabetic cardiomyopathy (DCM) is a unique form of cardiomyopathy that develops as a consequence of diabetes and significantly contributes to heart failure in patients. Esaxerenone, a selective non-steroidal mineralocorticoid receptor antagonist, has demonstrated potential in reducing the incidence of cardiovascular and renal events in individuals with chronic kidney and diabetes disease. However, the exact protective effects of esaxerenone in the context of DCM are still unclear. (2) Methods: The DCM model was successfully induced in mice by administering streptozotocin (55 mg/kg per day) for five consecutive days. After being fed a normal diet for 16 weeks, echocardiography was performed to confirm the successful establishment of the DCM model. Subsequent sequencing and gene expression analysis revealed significant differences in gene expression in the DCM group. These differentially expressed genes were identified as potential targets for DCM. By utilizing the Swiss Target Prediction platform, we employed predictive analysis to identify the potential targets of esaxerenone. A protein-protein-interaction (PPI) network was constructed using the common targets of esaxerenone and DCM. Enrichment analysis was conducted using Metascape. (3) Results: Compared to the control, the diabetic group exhibited impaired cardiac function and myocardial fibrosis. There was a total of 36 common targets, with 5 key targets. Enrichment analysis revealed that the chemokine and PI3K-Akt signaling pathway was considered a crucial pathway. A target-pathway network was established, from which seven key targets were identified. All key targets exhibited good binding characteristics when interacting with esaxerenone. (4) Conclusion: The findings of this study suggest that esaxerenone exhibits a favorable therapeutic effect on DCM, primarily by modulating the chemokine and PI3K-Akt signaling pathway.

CC chemokines and receptors in osteoarthritis: new insights and potential targets

Osteoarthritis (OA) is a prevalent degenerative disease accompanied by the activation of innate and adaptive immune systems-associated inflammatory responses. Due to the local inflammation, the expression of various cytokines was altered in affected joints, including CC motif chemokine ligands (CCLs) and their receptors (CCRs). As essential members of chemokines, CCLs and CCRs played an important role in the pathogenesis and treatment of OA. The bindings between CCLs and CCRs on the chondrocyte membrane promoted chondrocyte apoptosis and the release of multiple matrix-degrading enzymes, which resulted in cartilage degradation. In addition, CCLs and CCRs had chemoattractant functions to attract various immune cells to osteoarthritic joints, further leading to the aggravation of local inflammation. Furthermore, in the nerve endings of joints, CCLs and CCRs, along with several cellular factors, contributed to pain hypersensitivity by releasing neurotransmitters in the spinal cord. Given this family's diverse and complex functions, targeting the functional network of CCLs and CCRs is a promising strategy for the prognosis and treatment of OA in the future.

Identification of cuproptosis-associated subtypes and signature genes for diagnosis and risk prediction of Ulcerative colitis based on machine learning

Background

Ulcerative colitis (UC) is a chronic and debilitating inflammatory bowel disease that impairs quality of life. Cuproptosis, a recently discovered form of cell death, has been linked to many inflammatory diseases, including UC. This study aimed to examine the biological and clinical significance of cuproptosis-related genes in UC.

Methods

Three gene expression profiles of UC were obtained from the Gene Expression Omnibus (GEO) database to form the combined dataset. Differential analysis was performed based on the combined dataset to identify differentially expressed genes, which were intersected with cuproptosis-related genes to obtain differentially expressed cuproptosis-related genes (DECRGs). Machine learning was conducted based on DECRGs to identify signature genes. The prediction model of UC was established using signature genes, and the molecular subtypes related to cuproptosis of UC were identified. Functional enrichment analysis and immune infiltration analysis were used to evaluate the biological characteristics and immune infiltration landscape of signature genes and molecular subtypes.

Results

Seven signature genes (ABCB1, AQP1, BACE1, CA3, COX5A, DAPK2, and LDHD) were identified through the machine learning algorithms, and the nomogram built from these genes had excellent predictive performance. The 298 UC samples were divided into two subtypes through consensus cluster analysis. The results of the functional enrichment analysis and immune infiltration analysis revealed significant differences in gene expression patterns, biological functions, and enrichment pathways between the cuproptosis-related molecular subtypes of UC. The immune infiltration analysis also showed that the immune cell infiltration in cluster A was significantly higher than that of cluster B, and six of the characteristic genes (excluding BACE1) had higher expression levels in subtype B than in subtype A.

Conclusions

This study identified several promising signature genes and developed a nomogram with strong predictive capabilities. The identification of distinct subtypes of UC enhances our current understanding of UC's underlying pathogenesis and provides a foundation for personalized diagnosis and treatment in the future.

Swapping N-terminal regions among tick evasins reveals cooperative interactions influencing chemokine binding and selectivity

Class A tick evasins are natural chemokine-binding proteins that block the signaling of multiple chemokines from the CC subfamily through their cognate receptors, thus suppressing leukocyte recruitment and inflammation. Development of tick evasins as chemokine-targeted anti-inflammatory therapeutics requires an understanding of the factors controlling their chemokine recognition and selectivity. To investigate the role of the evasin N-terminal region for chemokine recognition, we prepared chimeric evasins by interchanging the N-terminal regions of four class A evasins, including a newly identified evasin, EVA-RPU02. We show through chemokine binding analysis of the parental and chimeric evasins that the N-terminal region is critical for chemokine binding affinity and selectivity. Notably, we found some chimeras were unable to bind certain cognate chemokine ligands of both parental evasins. Moreover, unlike any natural evasins characterized to date, some chimeras exhibited specific binding to a single chemokine. These results indicate that the evasin N terminus interacts cooperatively with the “body” of the evasin to enable optimum chemokine recognition. Furthermore, the altered chemokine selectivity of the chimeras validates the approach of engineering the N termini of evasins to yield unique chemokine recognition profiles.

Exosomes as Intercellular Messengers in Hypertension

People living with hypertension have a higher risk of developing heart diseases, and hypertension remains a top cause of mortality. In hypertension, some detrimental changes occur in the arterial wall, which include physiological and biochemical changes. Furthermore, this disease is characterized by turbulent blood flow, increased fluid shear stress, remodeling of the blood vessels, and endothelial dysfunction. As a complex disease, hypertension is thought to be caused by an array of factors, its etiology consisting of both environmental and genetic factors. The Mosaic Theory of hypertension states that many factors, including genetics, environment, adaptive, neural, mechanical, and hormonal perturbations are intertwined, leading to increases in blood pressure. Long-term efforts by several investigators have provided invaluable insight into the physiological mechanisms responsible for the pathogenesis of hypertension, and these include increased activity of the sympathetic nervous system, overactivation of the renin-angiotensin-aldosterone system (RAAS), dysfunction of the vascular endothelium, impaired platelet function, thrombogenesis, vascular smooth muscle and cardiac hypertrophy, and altered angiogenesis. Exosomes are extracellular vesicles released by all cells and carry nucleic acids, proteins, lipids, and metabolites into the extracellular environment. They play a role in intercellular communication and are involved in the pathophysiology of diseases. Since the discovery of exosomes in the 1980s, numerous studies have been carried out to understand the biogenesis, composition, and function of exosomes. In this review, we will discuss the role of exosomes as intercellular messengers in hypertension.

Honey and its nutritional and anti-inflammatory value

Inflammation is the main key role in developing chronic diseases including cancer, cardiovascular diseases, diabetes, arthritis, and neurodegenerative diseases which possess a huge challenge for treatment. With massively compelling evidence of the role played by nutritional modulation in preventing inflammation-related diseases, there is a growing interest into the search for natural functional foods with therapeutic and preventive actions. Honey, a nutritional healthy product, is produced mainly by two types of bees: honeybee and stingless bee. Since both types of honey possess distinctive phenolic and flavonoid compounds, there is recently an intensive interest in their biological and clinical actions against inflammation-mediated chronic diseases. This review shed the light specifically on the bioavailability and bioaccessibility of honey polyphenols and highlight their roles in targeting inflammatory pathways in gastrointestinal tract disorders, edema, cancer, metabolic and cardiovascular diseases and gut microbiota.

Endothelial Dysfunction in Primary Aldosteronism

Primary aldosteronism (PA) is characterized by excess production of aldosterone from the adrenal glands and is the most common and treatable cause of secondary hypertension. Aldosterone is a mineralocorticoid hormone that participates in the regulation of electrolyte balance, blood pressure, and tissue remodeling. The excess of aldosterone caused by PA results in an increase in cardiovascular and cerebrovascular complications, including coronary artery disease, myocardial infarction, stroke, transient ischemic attack, and even arrhythmia and heart failure. Endothelial dysfunction is a well-established fundamental cause of cardiovascular diseases and also a predictor of worse clinical outcomes. Accumulating evidence indicates that aldosterone plays an important role in the initiation and progression of endothelial dysfunction. Several mechanisms have been shown to contribute to aldosterone-induced endothelial dysfunction, including aldosterone-mediated vascular tone dysfunction, aldosterone- and endothelium-mediated vascular inflammation, aldosterone-related atherosclerosis, and vascular remodeling. These mechanisms are activated by aldosterone through genomic and nongenomic pathways in mineralocorticoid receptor-dependent and independent manners. In addition, other cells have also been shown to participate in these mechanisms. The complex interactions among endothelium, inflammatory cells, vascular smooth muscle cells and fibroblasts are crucial for aldosterone-mediated endothelial dysregulation. In this review, we discuss the association between aldosterone and endothelial function and the complex mechanisms from a molecular aspect. Furthermore, we also review current clinical research of endothelial dysfunction in patients with PA.

Identification of Biomarkers Associated with Septic Cardiomyopathy Based on Bioinformatics Analyses

This study intended to identify biomarkers for septic cardiomyopathy (SC). Microarray data GSE79962 including 20 SC samples and 11 normal samples were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between SC and control groups were identified, followed with functional enrichment analyses. In addition, the protein-protein interaction (PPI) network and modules were constructed. Finally, a transcription factors (TFs)-microRNA (miRNA)-target gene network was constructed and the potential drugs targeting key DEGs were searched. There were 119 upregulated and 80 downregulated genes in the SC group compared with the control group. The upregulated DEGs were significantly enriched tumor necrosis factor signaling pathway, Jak-signal transducer and activator of transcription (STAT) signaling pathway, hypoxia-inducible transcription factor-1 signaling pathway, chemokine signaling pathway, and cytokine-cytokine receptor interaction. The downregulated genes involved in biological processes of negative regulation of DNA biosynthetic process, and skeletal muscle cell differentiation. CCL2, STAT3, MYC, and SERPINE1 were hub nodes in the PPI network and modules. miR-29 family and miR-30 family were considered as key miRNAs, and TATA, MEF2, and STAT5B were considered as key TFs. SERPINE1 and MYC were also drug target genes. The identified DEGs and pathways may be implicated in the progression of human SC, which may lead to a better understanding of SC pathogenesis.

Comparative Transcriptome Analyses Provide Potential Insights into the Molecular Mechanisms of Astaxanthin in the Protection against Alcoholic Liver Disease in Mice

Alcoholic liver disease (ALD) is a major cause of chronic liver disease worldwide. It is a complex process, including a broad spectrum of hepatic lesions from fibrosis to cirrhosis. Our previous study suggested that astaxanthin (AST) could alleviate the hepatic inflammation and lipid dysmetabolism induced by ethanol administration. In this study, a total of 48 male C57BL/6J mice were divided into 4 groups: a Con group (fed with a Lieber–DeCarli liquid diet), an AST group (fed with a Lieber–DeCarli liquid diet and AST), an Et group (fed with an ethanol-containing Lieber–DeCarli liquid diet), and a EtAST group (fed with an ethanol-containing Lieber–DeCarli liquid diet and AST). Then, comparative hepatic transcriptome analysis among the groups was performed by Illumina RNA sequencing. Gene enrichment analysis was conducted to identify pathways affected by the differentially expressed genes. Changes of the top genes were verified by quantitative real-time PCR (qRT-PCR) and Western blot. A total of 514.95 ± 6.89, 546.02 ± 15.93, 576.06 ± 21.01, and 690.85 ± 54.14 million clean reads were obtained for the Con, AST, Et, and EtAST groups, respectively. Compared with the Et group, 1892 differentially expressed genes (DEGs) (including 351 upregulated and 1541 downregulated genes) were identified in the AST group, 1724 differentially expressed genes (including 233 upregulated and 1491 downregulated genes) were identified in the Con group, and 1718 DEGs (including 1380 upregulated and 338 downregulated genes) were identified in the EtAST group. The enrichment analyses revealed that the chemokine signaling, the antigen processing and presentation, the nucleotide-binding and oligomerization domain (NOD)-like receptor signaling, and the Toll-like receptor signaling pathways enriched the most differentially expressed genes. The findings of this study provide insights for the development of nutrition-related therapeutics for ALD.

Pathophysiology of Acute Illness and Injury

The pathophysiology of acute illness and injury recognizes three main effectors: infection, trauma, and ischemia-reperfusion injury. Each of them can act by itself or in combination with the other two in developing a systemic inflammatory reaction syndrome (SIRS) that is a generalized reaction to the morbid event. The time course of SIRS is variable and influenced by the number and severity of subsequent insults (e.g., reparative surgery, acquired hospital infections). It occurs simultaneously with a complex of counter-regulatory mechanisms (compensatory anti-inflammatory response syndrome, CARS) that limit the aggressive effects of SIRS. In adjunct, a progressive dysfunction of the acquired (lymphocytes) immune system develops with increased risk for immunoparalysis and associated infectious complications. Both humoral and cellular effectors participate to the development of SIRS and CARS. The most important humoral mediators are pro-inflammatory (IL-1β, IL-6, IL-8, IL-12) and anti-inflammatory (IL-4, IL-10) cytokines and chemokines, complement, leukotrienes, and PAF. Effector cells include neutrophils, monocytes, macrophages, lymphocytes, and endothelial cells. The endothelium is a key factor for production of remote organ damage as it exerts potent chemo-attracting effects on inflammatory cells, allows for leukocyte trafficking into tissues and organs, and promotes further inflammation by cytokines release. Moreover, the loss of vasoregulatory properties and the increased permeability contribute to the development of hypotension and tissue edema. Finally, the disseminated activation of the coagulation cascade causes the widespread deposition of microthrombi with resulting maldistribution of capillary blood flow and ultimately hypoxic cellular damage. This mechanism together with increased vascular permeability and vasodilation is responsible for the development of the multiple organ dysfunction syndrome (MODS).

Low shear stress upregulates the expression of fractalkine through the activation of mitogen-activated protein kinases in endothelial cells

Fractalkine (FKN) is a cytokine which plays an important role in atherosclerosis and other inflammatory diseases. Studies have shown that FKN induces integrin-independent leukocyte adhesion to primary endothelial cells under physiological flow conditions. Further, increased expression of FKN has been demonstrated in atherosclerotic lesions induced by low shear stress. However, the signal transduction mechanisms involved in low shear stress-induced FKN upregulation are not well characterized. In this study, EA.hy926 cells were subjected to varying intensity of fluid shear stress for different time durations. Further, mRNA and protein expressions of FKN were assessed by quantitative real-time PCR and Western blotting, respectively. Upregulation of FKN expression, which was induced via activation of mitogen-activated protein kinases signaling pathway under conditions of low shear stress, was studied both in the presence and absence of inhibitors. Low shear stress (∼4.58 dyne/cm²) for more than 1 h promoted FKN expression and activated the extracellular signal-regulated kinase (ERK)1/2, p38, and Jun N-terminal kinase (JNK) mitogen-activated protein kinases signaling pathways by their phosphorylation. Inhibitors of ERK1/2, p38, and JNK pathways downregulated the FKN expression. In this study, fluid shear stress affected FKN expression in endothelial cells via activation of ERK1/2, p38, and JNK in a time-dependent manner. Our findings serve to advance the theoretical basis for prevention and treatment of atherosclerosis.

In silico profiling of systemic effects of drugs to predict unexpected interactions

Identifying unexpected drug interactions is an essential step in drug development. Most studies focus on predicting whether a drug pair interacts or is effective on a certain disease without considering the mechanism of action (MoA). Here, we introduce a novel method to infer effects and interactions of drug pairs with MoA based on the profiling of systemic effects of drugs. By investigating propagated drug effects from the molecular and phenotypic networks, we constructed profiles of 5,441 approved and investigational drugs for 3,833 phenotypes. Our analysis indicates that highly connected phenotypes between drug profiles represent the potential effects of drug pairs and the drug pairs with strong potential effects are more likely to interact. When applied to drug interactions with verified effects, both therapeutic and adverse effects have been successfully identified with high specificity and sensitivity. Finally, tracing drug interactions in molecular and phenotypic networks allows us to understand the MoA.

Oncogenic mutations and dysregulated pathways in obesity-associated hepatocellular carcinoma

Epidemiological studies showed that obesity and its related non-alcoholic fatty liver disease (NAFLD) promote hepatocellular carcinoma (HCC) development. We aimed to uncover the genetic alterations of NAFLD-HCC using whole-exome sequencing. We compared HCC development in genetically obese mice and dietary obese mice with wild-type lean mice fed a normal chow after treatment with diethylnitrosamine. HCC tumor and adjacent normal samples from obese and lean mice were then subjected to whole-exome sequencing. Functional and mechanistic importance of the identified mutations in Carboxyl ester lipase (Cel) gene and Harvey rat sarcoma virus oncogene 1 (Hras) was further elucidated. We demonstrated significantly higher incidences of HCC in both genetic and dietary obese mice with NAFLD development as compared with lean mice without NAFLD. The mutational signatures of NAFLD-HCC and lean HCC were distinct, with <3% overlapped. Eight metabolic or oncogenic pathways were found to be significantly enriched by mutated genes in NAFLD-HCC, but only two of these pathways were dysregulated by mutations in lean HCC. In particular, Cel was mutated significantly more frequently in NAFLD-HCC than in lean HCC. The multiple-site mutations in Cel are loss-of-function mutations, with effects similar to Cel knock-down. Mutant Cel caused accumulation of cholesteryl ester in liver cells, which led to induction of endoplasmic reticulum stress and consequently activated the IRE1α/c-Jun N-terminal kinase (JNK)/c-Jun/activating protein-1 (AP-1) signaling cascade to promote liver cell growth. In addition, single-site mutations in Hras at codon 61 were found in NAFLD-HCC but none in lean HCC. The gain-of-function mutations in Hras (Q61R and Q61K) significantly promoted liver cell growth through activating the mitogen-activated protein kinase (MAPK) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/3-phosphoinositide-dependent protein kinase-1 (PDK1)/Akt pathways. In conclusion, we have identified mutation signature and pathways in NAFLD-associated HCC. Mutations in Cel and Hras have important roles in NAFLD-associated hepatocellular carcinogenesis.

Identifying roles of "Jun-Chen-Zuo-Shi" component herbs of QiShenYiQi formula in treating acute myocardial ischemia by network pharmacology

BACKGROUND

The role of "Jun-Chen-Zuo-Shi" (also known as "sovereign-minister-assistant-courier") component herbs of Chinese medicine is not fully understood. This study aims to test the "Jun-Chen-Zuo-Shi" rule with the QiShenYiQi formula (QSYQ) on treating acute myocardial ischemia (AMI) by a network pharmacology approach.

METHODS

An Acute Myocardial Ischemia (AMI) specific Organism Disturbed Network (AMI-ODN), was constructed by integrating data of disease-associated genes, protein-protein interaction and microarray experiments. A network-based index, Network Recovery Index for Organism Disturbed Network (NRI-ODN), was developed to measure the therapeutic efficacy of QSYQ and its ingredients, i.e., the ability to recover disturbed AMI network model back to normal state.

RESULTS

The whole formula of QSYQ got a NRI-ODN score of 864.48, which outperformed all individual herbs. Additionally, the primary component herbs, Radix Astragalus membranaceus and Radix Salvia miltiorrrhiza showed NRI-DON score of 680.27 and 734.31 respectively, which meant a better performance to recover disturbed AMI network than the supplementary component herbs, Panax notoginseng and Dalbergia sissoo did (545.76 and 584.88, respectively).

CONCLUSION

AMI-ODN model and NRI-ODN identified the possible roles of "Jun-Chen-Zuo-Shi" component herbs of QSYQ in treating AMI at molecular network and pathway level.

Roles of inflammation, oxidative stress, and vascular dysfunction in hypertension

Hypertension is a complex condition and is the most common cardiovascular risk factor, contributing to widespread morbidity and mortality. Approximately 90% of hypertension cases are classified as essential hypertension, where the precise cause is unknown. Hypertension is associated with inflammation; however, whether inflammation is a cause or effect of hypertension is not well understood. The purpose of this review is to describe evidence from human and animal studies that inflammation leads to the development of hypertension, as well as the evidence for involvement of oxidative stress and endothelial dysfunction--both thought to be key steps in the development of hypertension. Other potential proinflammatory conditions that contribute to hypertension-such as activation of the sympathetic nervous system, aging, and elevated aldosterone--are also discussed. Finally, we consider the potential benefit of anti-inflammatory drugs and statins for antihypertensive therapy. The evidence reviewed suggests that inflammation can lead to the development of hypertension and that oxidative stress and endothelial dysfunction are involved in the inflammatory cascade. Aging and aldosterone may also both be involved in inflammation and hypertension. Hence, in the absence of serious side effects, anti-inflammatory drugs could potentially be used to treat hypertension in the future.

Gene expression profiles in intracranial aneurysms

In this study, we extracted total RNA from 15 intracranial aneurysms and 17 superficial temporal artery samples, then performed genome-wide expression profiling using the Affymetrix U133 Plus 2.0 GeneChip. Genes that were differentially expressed between intracranial aneurysms and arterial samples were identified using significance analysis for microarrays, and the expression patterns of three randomly-selected genes were verified by real-time polymerase chain reaction analysis. We identified 3 736 differentially-expressed genes out of the 47,000 assayed transcripts. A total of 179 genes showed a >10-fold change in expression between the aneurysms and the arterial samples. Genes involved in the proliferation, migration, and apoptosis of vascular muscle cells, atherosclerosis, extracellular matrix disruption, and inflammatory reactions were associated with the formation of intracranial aneurysms. There were no significant differences in gene expression profile between unruptured and ruptured aneurysms.

Adenosine receptor A2b on hematopoietic cells mediates LPS-induced migration of PMNs into the lung interstitium

Uncontrolled transmigration of polymorphonuclear leukocytes (PMNs) into the different compartments of the lungs (intravascular, interstitial, alveolar) is a critical event in the early stage of acute lung injury and acute respiratory distress syndrome. Adenosine receptor A2b is highly expressed in the inflamed lungs and has been suggested to mediate cell trafficking. In a murine model of LPS-induced lung inflammation, we investigated the role of A2b on migration of PMNs into the different compartments of the lung. In A2b−/− mice, LPS-induced accumulation of PMNs was significantly higher in the interstitium, but not in the alveolar space. In addition, pulmonary clearance of PMNs was delayed in A2b−/− mice. Using chimeric mice, we identified A2b on hematopoietic cells as crucial for PMN migration. A2b did not affect the release of relevant chemokines into the alveolar space. LPS-induced microvascular permeability was under the control of A2b on both hematopoietic and nonhematopoietic cells. Activation of A2b on endothelial cells also reduced formation of LPS-induced stress fibers, highlighting its role for endothelial integrity. A specific A2b agonist (BAY 60–6583) was effective in decreasing PMN migration into the lung interstitium and microvascular permeability. In addition, in vitro transmigration of human PMNs through a layer of human endothelial or epithelial cells was A2b dependent. Activation of A2b on human PMNs reduced oxidative burst activity. Together, our results demonstrate anti-inflammatory effects of A2b on two major characteristics of acute lung injury, with a distinct role of hematopoietic A2b for cell trafficking and endothelial A2b for microvascular permeability.

The role and source of tumor necrosis factor-α in hemorrhage-induced priming for septic lung injury

Tumor necrosis factor α (TNF-α) has been reported to be a key component of the functional priming, of both myeloid and nonmyeloid cells, that is thought to contribute to the lung's increased susceptibility to injury following shock. Not surprisingly, we found that mice deficient in TNF-α exhibited reduced acute lung injury (ALI) resultant from the combined insults of hemorrhagic shock and sepsis. However, we found that when we adoptively transferred neutrophils from mice expressing TNF-α to neutrophil-depleted mice that lacked TNF-α, they were not able to serve as priming stimulus for the development of ALI. Based on these findings, we proposed that resident lung tissue cells mediate TNF-α priming. To begin to unravel the complex signaling pathway of various resident lung tissue cells in TNF-α-induced priming, we compared the effect of local (intratracheal [i.t.]) versus systemic [intravenous (i.v.)] delivery of TNF-α small interference (siRNA). We hypothesized that alternately suppressing expression of TNF-α in lung endothelial (i.v.) or epithelial (i.t.) cells would produce a differential effect in shock-induced ALI. We found that when in vivo siRNA i.t. or i.v. against TNF-α was administered to C57/BL6 mice at 2 h after hemorrhage, 24 h before septic challenge, that systemic/i.v., but not i.t., delivery of TNF-α siRNA following hemorrhage priming significantly reduces expression of indices of ALI compared with controls. These findings suggest that an absence of local lung tissue TNF-α significantly reduces lung tissue injury following hemorrhage priming for ALI and that pulmonary endothelial and/or other possible vascular resident cells, not epithelial cells, play a greater role in mediating the TNF-α priming response in a mouse model of hemorrhage/sepsis-induced ALI.

Differential flux of macrophage inflammatory protein-2 and cytokine-induced neutrophil chemoattractant from the lung after intrapulmonary delivery

Previously we showed that cytokine-induced neutrophil chemoattractant (CINC), but not macrophage inflammatory protein-2 (MIP-2), is detected in plasma after intratracheal challenge with LPS or the particular chemokines. To further understand the differences between CINC and MIP-2 flux from the lung, we attempted to detect the two chemokines in isolated erythrocytes and leukocytes in rats after intratracheal LPS challenge. In response to intratracheal LPS, we found both CINC and MIP-2 in isolated erythrocytes and leukocytes, suggesting that MIP-2 produced in the LPS-challenged lung entered the circulation like CINC. To assess the relative flux of CINC and MIP-2 from the intra-alveolar compartment into the blood, experiments were performed in rats implanted with vascular catheters in which both chemokines were either injected intratracheally (5 μg) or infused intravenously (20 ng/min) and subsequently measured in plasma or with the cellular elements. Both chemokines appeared in the blood following intratracheal injection, with CINC detected in plasma and cells but MIP-2 only detected in the cellular fraction of blood. Infusion of both chemokines allowed detection of MIP-2 and CINC in plasma and with the cellular elements, which allowed us to calculate clearance for each chemokine and to assess CINC and MIP-2 rates of appearance (Ra) following intratracheal injection. On the basis of plasma and whole blood clearance, CINC Ra was more than sevenfold and fourfold higher, respectively, than MIP-2 Ra. This analysis indicates that differences exist in the rate of flux of CINC and MIP-2 across the epithelial/endothelial barrier of the lung, despite similar molecular size.

Fractalkine/CX3CR1 and atherosclerosis

Fractalkine is a unique chemokine which has both adhesive and chemoattractant functions. With the increasing emphasis on the importance of inflammation in atherosclerosis, more attention has been focused on the role of chemokines in atherosclerosis. It has been shown that fractalkine/CX3CR1 participates in the atherosclerotic pathological process through mediating the recruitment of leukocytes and the interaction of vascular cells and leukocytes. Some signal pathways are simultaneously activated through fractalkine/CX3CR1 coupling to promote the inflammatory response in atherosclerotic vessels. Additionally, fractalkine has cytotoxic effects on endothelium as well as anti-apoptosis and proliferative effects on vascular cells which consequently changes plaque components and stability in plaque. Several studies have showed that fractalkine or CX3CR1 deficiency in atherosclerotic mice would ameliorate the severity of plaque. Population studies on CX3CR1 polymorphism have confirmed that 280M-containing haplotype is associated with reduced risk of atherosclerotic disease. Despite the apparent association with atherosclerosis, further studies on fractalkine/CX3CR1 chemokine pair are clearly warranted to more fully elucidate this relationship.

Involvement of nitric oxide in a rat model of carrageenin-induced pleurisy

Some evidence indicates that nitric oxide (NO) contributes to inflammation, while other evidence supports the opposite conclusion. To clarify the role of NO in inflammation, we studied carrageenin-induced pleurisy in rats treated with an NO donor (NOC-18), a substrate for NO formation (L-arginine), and/or an NO synthase inhibitor (S-(2-aminoethyl) isothiourea or N^G-nitro-L-arginine). We assessed inflammatory cell migration, nitrite/nitrate values, lipid peroxidation and pro-inflammatory mediators. NOC-18 and L-arginine reduced the migration of inflammatory cells and edema, lowered oxidative stress, and normalized antioxidant enzyme activities. NO synthase inhibitors increased the exudate formation and inflammatory cell number, contributed to oxidative stress, induced an oxidant/antioxidant imbalance by maintaining high O₂⁻, and enhanced the production of pro-inflammatory mediators. L-arginine and NOC-18 reversed the proinflammatory effects of NO synthase inhibitors, perhaps by reducing the expression of adhesion molecules on endothelial cells. Thus, our results indicate that NO is involved in blunting—not enhancing—the inflammatory response.

Increased inflammatory markers in brain and blood of rats subjected to acute homocysteine administration

Hyperhomocysteinemia plays an etiologic role in the pathogenesis of disorders, including homocystinuria and neurodegenerative and cardiovascular diseases. In the present study, we studied the effect of acute administration of homocysteine, similar to that found in homocystinuria, on parameters of inflammation such as cytokines (TNF-alpha, IL-1beta and IL-6), chemokine CCL2 (MCP-1), nitrite and acute phase-proteins (C-reactive protein and alpha(1)-Acid glycoprotein) levels in brain and blood of rats. In addition, a differential count of blood leukocytes was performed. Wistar rats, aged 29 days, received a single subcutaneous injection of saline (control) or homocysteine (0.6 micromol/g body weight). Fifteen minutes, 1 h, 6 h or 12 h after the injection, the rats were sacrificed and serum, hippocampus and cerebral cortex were used. Results showed that homocysteine significantly increased proinflammatory cytokines (TNF-alpha, IL-1beta and IL-6) and chemokine CCL2 (MCP-1) in serum, hippocampus and cerebral cortex. Nitrite levels also increased in hippocampus and cerebral cortex at 15 min, 1 h and 6 h, but not 12 h after homocysteine administration. Acute phase-protein levels were not altered by homocysteine. The percentage of neutrophils and monocytes significantly increased in blood at 15 min and 1 h, but not at 6 h and 12 h after acute hyperhomocysteinemia, when compared to the control group. Our results showed that acute administration of homocysteine increased inflammatory parameters, suggesting that inflammation might be associated, at least in part, with the neuronal and cardiovascular dysfunctions observed in homocystinuric patients.

Inflammatory cytokines as predictive markers for early detection and progression of diabetic nephropathy

Diabetic nephropathy is a major complication of diabetes mellitus and the leading cause of end-stage renal disease. Both hyperglycemia and hypertension (systemic and/or intraglomerular) are established causal factors for diabetic nephropathy. Nonetheless, there is growing evidence that activated innate immunity and inflammation are also contributing factors to the pathogenesis of diabetic nephropathy. This notion is based on increasing evidence indicating that both cytokines-chemokines and pro-fibrotic growth factors are important players in the progression of diabetic nephropathy, effectively accelerating and exacerbating inflammatory and fibrotic processes leading to end-stage renal disease. In this review, we focus on several predominant cytokines-chemokines as potential predictive markers for diabetic nephropathy. These cytokines-chemokines may also be helpful as biomarkers to monitor the progression of the disease and the impact of interventional modalities aimed at halting eventual manifestation of end-stage renal disease in diabetic patients.

Anti-Inflammatory effects of low-level laser therapy (660 nm) in the early phase in carrageenan-induced pleurisy in rat

BACKGROUND AND OBJECTIVE

In the classic model of pleurisy there is little evidence about the anti-inflammatory effects of low-level laser therapy (LLLT) as well the dosage characteristics, such as wavelength, total energy, number and pattern of treatment. In this study we investigated the potential effects of LLLT on modulating the pro-inflammatory and anti-inflammatory mediators of acute inflammation in a rat pleurisy model.

STUDY DESIGN/MATERIALS AND METHODS

A sample of 48 female Wistar rats were divided into control and experiential groups. An inflammation was induced by carrageenan (0.2 ml) injected into the pleural cavity. At 1, 2, and 3 hours after induction a continuous wave (20 mW) diode laser of the InGaAlP (660 nm) type was used in the four laser groups with different doses and treatment patterns. One group received a single dose of 2.1 J and the other three groups received a total energy of 0.9, 2.1, and 4.2 J. Four hours later the exudate volume, total and differential leukocytes, protein concentration, NO, IL-6, IL-10, TNF-alpha, and MCP-1 were measured from the aspirated liquid.

RESULTS

All the treatment patterns and quantity of energy studied show significant reduction of the exudate volume (P<0.05). Using energy of 0.9 J only NO, IL-6, MCP-1 and IL-10 are significantly reduced (P<0.05). On the other hand, higher energies (2.1 and 4.2 J) significantly reduce all variables independently of the treatment pattern. The neutrophil migration has a straight correlation with the TNF-alpha (r = 0.551) and NO (r = 0.549) concentration.

CONCLUSIONS

LLLT-660 nm induced an anti-inflammatory effect characterized by inhibition of either total or differential leukocyte influx, exudation, total protein, NO, IL-6, MCP-1, IL-10, and TNF-alpha, in a dose-dependent manner. Under these conditions, laser treatment with 2.1 J was more effective than 0.9 and 4.2 J.

Roles of CXCL8 in squamous cell carcinoma proliferation and migration

Previous work from our laboratory has demonstrated overexpression of chemokines in head and neck cancer, and the utility of targeting CXCL5 for tumor therapy in a preclinical model. In the present study, we investigated the contribution of a related chemokine, CXCL8, to cellular properties associated with tumor progression, namely cell growth and motility. Expression of CXCL8 was detectable in multiple squamous carcinoma cell lines, indicating a possible role in pathogenesis. Overexpression of CXCL8 in HN4 primary tumor cells with low endogenous CXCL8 levels was found to increase cell growth, as judged by cell counting and MTT assays. Conversely, RNAi-mediated knockdown of CXCL8 expression in HN12 cells, derived from a synchronous metastasis and which express high levels of this chemokine, resulted in a decrease in proliferation. Similarly, overexpression of CXCL8 enhanced migration of HN4 cells, while suppression of CXCL8 inhibited HN12 cell migration and invasion through a basement membrane substitute. Taken together, these findings support the hypothesis that CXCL8 affects multiple processes involved in tumor progression and identify CXCL8 as a potential therapeutic target, similar to CXCL5.

Systemic inflammation after trauma

Trauma is still one of the main reasons for death among the population worldwide. Mortality occurring early after injury is due to "first hits", including severe organ injury, hypoxia, hypovolaemia or head trauma. Massive injury leads to activation of the immune system and the early inflammatory immune response after trauma has been defined as systemic inflammatory response syndrome (SIRS). "Second hits" such as infections, ischaemia/reperfusion or operations can further augment the pro-inflammatory immune response and have been correlated with the high morbidity and mortality in the latter times after trauma. SIRS can lead to tissue destruction in organs not originally affected by the initial trauma with subsequent development of multi-organ dysfunction (MOD). The initial pro-inflammatory response is followed by an anti-inflammatory response and can result in immune suppression with high risk of infection and sepsis. Trauma causes activation of nearly all components of the immune system. It activates the neuroendocrine system and local tissue destruction and accumulation of toxic byproducts of metabolic respiration leads to release of mediators. Extensive tissue injury may result in spillover of these mediators into the peripheral bloodstream to further maintain and augment the pro-inflammatory response. Hormones like ACTH, corticosteroids and catecholamines as well as cytokines, chemokines and alarmins play important roles in the initiation and persistence of the pro-inflammatory response after severe injury. The purpose of this review is therefore to describe the immunological events after trauma and to introduce important mediators and pathways of the inflammatory immune response.

Roles of neutrophil-mediated inflammatory response in the bony repair of injured growth plate cartilage in young rats

Injured growth plate cartilage is often repaired by bony tissue, resulting in impaired bone growth in children. Previously, injury-induced, initial inflammatory response was shown to be an acute inflammatory event containing predominantly neutrophils. To examine potential roles of neutrophils in the bony repair, a neutrophil-neutralizing antiserum or control normal serum was administered systemically in rats with growth plate injury. The inflammatory response was found temporally associated with increased expression of neutrophil chemotactic chemokine cytokine-induced neutrophil chemoattractant-1 and cytokines TNF-alpha and IL-1beta. Following the inflammatory response, mesenchymal infiltration, chondrogenic and osteogenic responses, and bony repair were observed at the injury site. Neutrophil reduction did not significantly affect infiltration of other inflammatory cells and expression of TNF-alpha and IL-1beta and growth factors, platelet-derived growth factor-B and TGF-beta1, at the injured growth plate on Day 1 and had no effects on mesenchymal infiltration on Day 4. By Day 10, however, there was a significant reduction in proportion of mesenchymal repair tissue but an increase (although statistically insignificant) in bony trabeculae and a decrease in cartilaginous tissue within the injury site. Consistently, in antiserum-treated rats, there was an increase in expression of osteoblastic differentiation transcription factor cbf-alpha1 and bone matrix protein osteocalcin and a decrease in chondrogenic transcription factor Sox-9 and cartilage matrix collagen-II in the injured growth plate. These results suggest that injury-induced, neutrophil-mediated inflammatory response appears to suppress mesenchymal cell osteoblastic differentiation but enhance chondrogenic differentiation, and thus, it may be involved in regulating downstream chondrogenic and osteogenic events for growth plate bony repair.

Regulation of chemokine production in response to pro-inflammatory cytokines in first trimester decidual cells

OBJECTIVE

Chemokines initiate the immune response by controlling leukocyte migration and lymphocyte development. Macrophage infiltration of the decidua has been implicated in the genesis of recurrent miscarriage and preeclampsia. Therefore, we determined whether cultured human decidual cells produce monocyte/macrophage-recruiting chemokines in response to a potent pro-inflammatory cytokine, interleukin-1beta (IL-1beta), and whether decidual cell-conditioned medium contains monocyte- and macrophage-chemoattractant activity.

METHODS

Leukocyte-free first trimester decidual cells were treated for 6h with estradiol (E(2)) and medroxyprogesterone acetate (MPA) to mimic the steroidal milieu of pregnancy, or E(2) and MPA and IL-1beta (1 ng/ml) to mimic inflamed decidua. Total RNA was used for cDNA synthesis. Biotinylated cRNAs were generated and chemically fragmented for hybridization on Affymetrix HG_U133 Plus 2.0 chips followed by fluorescence labeling and optical scanning. Raw data generated from Affymetrix GCOS 1.2 (GeneChip Operating Software) were analyzed by GeneSpring 7.2 software. Subsequently microarray results were validated by real time RT-PCR and Western blotting. A functional study of monocyte migration was carried out also using conditioned media from culture.

RESULTS

Five chemokines responsible for monocyte/macrophage chemoattraction and activation, including C-C motif ligand 2 (CCL2), CCL5, C-X-C motif ligand 2 (CXCL2), CXCL3 and CXCL8, were markedly elevated from 29- to 975-fold after exposure to IL-1beta in cultured first trimester decidual cells. The results of real-time RT-PCR (up-regulation from 43- to 3069-fold) and Western blotting (up-regulation from 15- to 300-fold) confirmed the microarray findings. Monocyte migration was significantly induced by the conditioned medium from IL-1beta-treated decidual cells.

CONCLUSIONS

Treatment of first trimester decidual cells with IL-1beta induces secretion of monocyte/macrophage recruiting-chemokines and promotes monocyte migration. Extrapolation of these in vitro results to the milieu of implantation site suggests a mechanism whereby IL-1beta could mediate excessive macrophage infiltration of the decidua.

MCP-1/CCL2 protects cardiac myocytes from hypoxia-induced apoptosis by a G(alphai)-independent pathway

Chemokines, in addition to their chemotactic properties, act upon resident cells within a tissue and mediate other cellular functions. In a previous study, we demonstrated that CCL2 protects cultured mouse neonatal cardiac myocytes from hypoxia-induced cell death. Leukocyte chemotaxis has been shown to contribute to ischemic injury. While the chemoattractant properties of CCL2 have been established, the protective effects of this chemokine suggest a novel role for CCL2 in myocardial ischemia/reperfusion injury. The present study examined the cellular signaling pathways that promote this protection. Treatment of cardiac myocyte cultures with CCL2 protected them from hypoxia-induced apoptosis. This protection was not mediated through the activation of G(alphai) signaling that mediates monocyte chemotaxis. Inhibition of the ERK1/2 signaling pathway abrogated CCL2 protection. Caspase 3 activation and JNK/SAPK phosphorylation were decreased in hypoxic myocytes co-treated with CCL2 as compared to hypoxia only-treated cultures. Expression of the Bcl-2 family proteins, Bcl-xL and Bag-1, was increased in CCL2-treated myocytes subjected to hypoxia. There was also downregulation of Bax protein levels as a result of CCL2 co-treatment. These data suggest that CCL2 cytoprotection and chemotaxis may occur through distinct signaling mechanisms.

Leukotriene B4 receptor (BLT-1) modulates neutrophil influx into the peritoneum but not the lung and liver during surgically induced bacterial peritonitis in mice

Leukotriene B4 (LTB4) is a rapidly synthesized, early neutrophil chemoattractant that signals via its cell surface receptor, BLT-1, to attract and activate neutrophils during peritonitis. BLT-1-deficient (BLT-1(-/-)) mice were used to determine the effects of LTB4 on neutrophil migration and activation, bacterial levels, and survival after cecal ligation and puncture (CLP). Male BLT-1(-/-) or wild-type (WT) BALB/c mice underwent CLP. Tissues were harvested for determination of levels of bacteria, myeloperoxidase (MPO), LTB4, macrophage inflammatory protein 2 (MIP-2), and neutrophil (polymorphonuclear leukocyte [PMN]) numbers at 4 and 18 h after CLP. PMN activation was determined by an assessment of phagocytosis ability and CD11b expression. Survival was also determined. BLT-1(-/-) mice had decreased numbers of PMNs in the peritoneum at both 4 and 18 h after CLP but increased numbers of PMNs in the blood at 18 h compared with WT mice. Liver and lung MPO levels were significantly higher in BLT-1(-/-) mice at both 4 and 18 h after CLP, with increased bacterial levels in the blood, the liver, and peritoneal fluid at 4 h. Bacterial levels remained higher in peritoneal fluid at 18 h, but blood and liver bacterial levels at 18 h were not different from levels at 4 h. PMN phagocytosis and CD11b levels were decreased in BLT-1(-/-) mice. LTB4 levels were similar between the groups before and after CLP, but MIP-2 levels were decreased both locally and systemically in BLT-1(-/-) mice. Survival was significantly improved in BLT-1(-/-) mice (71%) compared with WT mice (14%) at 48 h post-CLP. Thus, LTB4 modulates neutrophil migration into the mouse peritoneum, but not the lung or liver, after CLP. Despite higher bacterial and PMN levels at remote sites, there was increased survival in BLT-1(-/-) mice compared to WT mice. Decreased PMN activation may result in less remote organ dysfunction and improved survival.

Chemokines in acute respiratory distress syndrome

A characteristic feature of all inflammatory disorders is the excessive recruitment of leukocytes to the site of inflammation. The loss of control in trafficking these cells contributes to inflammatory diseases. Leukocyte recruitment is a well-orchestrated process that includes several protein families including the large cytokine subfamily of chemotactic cytokines, the chemokines. Chemokines and their receptors are involved in the pathogenesis of several diseases. Acute lung injury that clinically manifests as acute respiratory distress syndrome (ARDS) is caused by an uncontrolled systemic inflammatory response resulting from clinical events including major surgery, trauma, multiple transfusions, severe burns, pancreatitis, and sepsis. Systemic inflammatory response syndrome involves activation of alveolar macrophages and sequestered neutrophils in the lung. The clinical hallmarks of ARDS are severe hypoxemia, diffuse bilateral pulmonary infiltrates, and normal intracardiac filling pressures. The magnitude and duration of the inflammatory process may ultimately determine the outcome in patients with ARDS. Recent evidence shows that activated leukocytes and chemokines play a key role in the pathogenesis of ARDS. The expanding number of antagonists of chemokine receptors for inflammatory disorders may hold promise for new medicines to combat ARDS.

cCXCR1 is a receptor for cIL-8 (9E3/cCAF) and its N- and C-terminal peptides and is also activated by hIL-8 (CXCL8)

Chemokines are chemotactic cytokines that play important roles in immune responses and wound healing, as well as in pathological conditions such as chronic inflammation and tumorigenesis. The chemokines and their receptors are highly conserved and maintain similar functions in different species. One noteworthy exception is the chemokine interleukin (IL)8/CXC ligand 8 and its specific receptor CXCR1, which are found in humans but are not found in the traditional model organisms, mice and rats. As a consequence, we are using model organisms other than mice to study the functions of IL-8 and CXCR1, as well as the mechanisms involved in receptor activation by IL-8. Toward this goal, we have isolated and characterized a new receptor that is highly homologous to human (h)CXCR1, which we named chicken (c)CXCR1. To determine whether this receptor is activated by cIL-8 and its N- and C-terminal peptides and whether it responds to hIL-8, we expressed cCXCR1 in NIH3T3 cells, which naturally lack this receptor, and used single-cell Ca(2)(+) imaging to detect increases in intracellular Ca(2)(+) and immunoblot analysis to detect extracellular signal-regulated kinase 1/2 phosphorylation. We show that cIL-8, its N and C peptides, and hIL-8 activate cCXCR1. We further show that cIL-8 and hIL-8 stimulate chemotaxis of chicken embryonic fibroblasts, cells that express cCXCR1, and that this effect is specific for each chemokine and this receptor. These results strongly suggest that cCXCR1 is the ortholog for hCXCR1 and that chickens can be used as an effective model system to study the functions of IL-8, its terminal peptides, and its specific receptor CXCR1.

Role of endogenous macrophage inflammatory protein-2 in regulating fever induced by bacterial endotoxin in normal and immunosuppressed rats

During myelosuppressive chemotherapy, Gram-negative bacterial infection with consequent exposure to lipopolysaccharide (LPS) is one of the most important causes of persistent fever. The classical model of the pathogenesis of fever suggests that pro-inflammatory cytokines, produced by leucocytes in the bloodstream in response to exogenous pyrogens such as bacterial LPS, represent the distal mediators of the febrile response. Neutrophils are the first effectors cells and the most prominent leucocyte population involved in acute bacterial infection. Macrophage inflammatory protein (MIP)-2 plays a crucial role in influencing early cell trafficking and neutrophil activation during pathophysiological processes and serves the same chemotactic function as human interleukin-8. In the present study, we investigated the role of MIP-2 in the development of a febrile response induced by LPS in immunocompetent and leukopenic rats. Intraperitoneal injection of LPS in leukopenic rats elicited a biphasic febrile response of rapid onset, the magnitude and duration of which were significantly greater than in immunocompetent animals. The febrile responses to LPS were accompanied by a pronounced induction of serum MIP-2 levels at 1, 2 and 4 h compared with their respective controls. In both normal and leukopenic rats, neutralization of endogenous MIP-2 bioactivity by systemic administration of antirat MIP-2 antibody caused a significant attenuation of the early phase of LPS fever. However, in contrast with normal rats, the second phase of fever was unimpaired by anti-MIP-2 in leukopenic rats. These findings suggest that circulating MIP-2 is involved in the generation of the early phase of LPS fever that contributes to the maintenance of the later phase of fever in immunocompetent, but not leukopenic, rats. Our data support a regulatory role for endogenous MIP-2 in initiating the fever responses to LPS. Furthermore, these results provide evidence that different cellular and humoral mechanisms are implicated in the development of a febrile response triggered by Gram-negative bacterial infections in leukopenic hosts.

The use of membrane translocating peptides to identify sites of interaction between the C5a receptor and downstream effector proteins

The complement fragment C5a is a potent leucocyte chemoattractant and activator, mediating its effects through a G-protein-coupled receptor. Whilst the C-terminal domain of this receptor has been shown to be essential for receptor desensitization and internalization, it is not known which domains couple to the receptor's heterotrimeric G proteins. In this report we have used a membrane translocating sequence (MTS) to examine the effects of the four intracellular domains of the human C5a receptor (C5aR) on the receptor's signalling via G(alphai) family heterotrimeric G proteins in intact RBL-2H3 cells. The results indicate that all of the intracellular domains couple to downstream signalling, with the proximal region of the C terminus being a major binding site and intracellular loop 3 playing a role in G protein activation or receptor desensitization.

The remote ischemic preconditioning stimulus modifies inflammatory gene expression in humans

Remote ischemic preconditioning (IPC) reduces tissue injury caused by ischemia-reperfusion (IR) in distant organs. We tested the hypothesis that remote IPC (rIPC) modifies inflammatory gene transcription in humans. Using a microarray method, we demonstrated that a simple model of brief forearm ischemia suppresses proinflammatory gene expression in circulating leukocytes. Genes encoding key proteins involved in cytokine synthesis, leukocyte chemotaxis, adhesion and migration, exocytosis, innate immunity signaling pathways, and apoptosis were all suppressed within 15 min (early phase IPC) and more so after 24 h (second window IPC). Changes in leukocyte CD11b expression measured by flow cytometry mirrored this pattern, with there being a significant (P = 0.01) reduction at 24 h. The results of this study show that the rIPC stimulus modifies leukocyte inflammatory gene expression. This effect may contribute to the protective effect of IPC against IR injury and may have broader implications in other inflammatory processes. This is the first study of human gene expression following rIPC stimulus. rIPC stimulus suppressed proinflammatory gene transcription in human leukocytes.

The impact of heparin compounds on cellular inflammatory responses: a construct for future investigation and pharmaceutical development

Atherosclerotic disease is recognized as a chronic inflammatory disorder with intermittent and widely variable phases of cellular proliferation and heightened thrombotic activity. The multi-tiered links between inflammation, atherogenesis and thrombogenesis provide a unique opportunity for research and development of pharmaceuticals which target one or more critical pathobiologic steps (Fig. 1). The purpose of the following review on heparin compounds is to comprehensively examine the multi-cellular, pleuripotential effects of a commonly used anticoagulant drug in the context of normal and disease-altered vascular responses and illustrate possible constructs for avenues of subsequent investigation in the field of atherothrombosis. The overview is divided into five integrated parts; antiinflammatory properties of the normal vessel wall, the relationship between glycosaminoglycans and inflammation, heparin-mediated effects on cellular inflammatory responses, association between molecular weight and antiinflammatory capabilities, and oral heparin compounds for achieving prolonged cell-based inhibition.

CXCR4 engagement is required for HIV-1–induced L-selectin shedding

The chemokine receptor, CXCR4, serves as the primary coreceptor for entry of T-cell tropic human immunodeficiency virus (HIV). Binding of either the CXC-chemokine, stromal-derived factor 1α (SDF-1α), or a CXCR4 antagonist, AMD3100, to CXCR4 inhibits infection of CD4+ T cells by T-tropic HIV-1, although only SDF-1α triggers T-cell signaling cascades. We have previously demonstrated that ligation of CD4 by T-cell tropic HIV-1 NL4-3 induces metalloproteinase-dependent L-selectin (CD62L) shedding on resting CD4+ T cells. However, the role of CXCR4 in HIV-induced L-selectin shedding is unclear. Here, we show that L-selectin shedding induced by HIV-1 NL4-3 is completely reversed by AMD3100, but not SDF-1α, although SDF-1α alone does not induce L-selectin shedding. These results indicate that engagement of both CD4 and CXCR4 is required for HIV-induced shedding of L-selectin on primary resting CD4+ T cells.

Identification and characterization of a glycosaminoglycan recognition element of the C chemokine lymphotactin

Chemokine-mediated recruitment of leukocytes in vivo depends on interactions with cell surface glycosaminoglycans. Lymphotactin, the unique member of the "C" chemokine subclass, is a highly basic protein that binds heparin, a glycosaminoglycan, with high affinity (approximately 10 nm). We detected lymphotactin-heparin binding by NMR and mapped this interaction to a narrow surface that wraps around the protein. Substitutions in and around this binding site and surface plasmon resonance analysis of heparin binding affinity identified two arginine residues of lymphotactin as critical for glycosaminoglycan binding. Both arginine mutant proteins and the combined double mutant had dramatically diminished in vivo activity in a leukocyte recruitment assay, suggesting that the lymphotactin-glycosaminoglycan interactions detected in vitro are important for the function of this chemokine. Our results demonstrate that like other chemokines, lymphotactin utilizes highly specific glycosaminoglycan-binding sites that represent potential targets for drug development.

Lidocaine attenuates monocyte chemoattractant protein-1 production and chemotaxis in human monocytes: possible mechanisms for its effect on inflammation

The recruitment and activation of peripheral blood monocytes are potentially critical regulatory events for the control of inflammation. Increased levels of monocyte chemoattractant protein (MCP)-1 have been reported in several inflammatory disorders. In this study, we examined the effect of lidocaine on lipopolysaccharide-stimulated MCP-1 secretion and MCP-1 induced chemotaxis in a human monocytic cell line, THP-1. Lidocaine inhibited lipopolysaccharide-induced MCP-1 production as well as messenger RNA expression in a dose-dependent manner. Furthermore, we demonstrated that lidocaine suppressed MCP-1-induced chemotaxis and peak cytosolic-free calcium in THP-1 cells. These results suggest that lidocaine may modulate MCP-1 production and MCP-1-induced activation in inflammatory cells.

IMPLICATIONS

Monocyte chemoattractant protein-1 (MCP-1) plays important roles in the inflammatory processes. Lidocaine may modulate MCP-1-induced monocyte response, as reflected by chemotaxis, cytosolic-free calcium, and lipopolysaccharide-induced MCP-1 production by human monocytic THP-1 cells.

Burkholderia cepacia-induced IL-8 gene expression in an alveolar epithelial cell line: signaling through CD14 and mitogen-activated protein kinase

Burkholderia cepacia is a prevalent pulmonary pathogen in patients with cystic fibrosis (CF). The lung pathology observed in patients with CF is postulated to be due to an overexpression of chemokines. This study investigated the induction of the neutrophil chemoattractant chemokine IL-8 and the signaling pathways activated by B. cepacia-infected human lung epithelial A549 (HLE) cells. Cells were infected with B. cepacia (genomovar III of the B. cepacia complex), and reverse transcriptase-PCR and ELISA for the cytokines were performed. B. cepacia (multiplicity of infection > or =4:1) induced HLE cells to significantly secrete IL-8 in a more potent manner than the predominant CF pathogen Pseudomonas aeruginosa (multiplicity of infection > or =64:1). IL-8 secretion by B. cepacia-infected HLE cells was abrogated by the gene transcription inhibitor actinomycin D and the protein translation inhibitor cycloheximide, confirming that B. cepacia-induced IL-8 secretion was mediated through de novo protein synthesis. Treatment of B. cepacia with proteinase K failed to down-regulate IL-8 secretion; furthermore, IL-8 secretion by B. cepacia-infected HLE cells was abrogated by > or =80% in the presence of anti-CD14 [specific lipopolysaccharide (LPS) receptor] antibody, thus suggesting that the IL-8-inducing component of B. cepacia was LPS and therefore dependent on CD14. The p38 mitogen-activated protein kinase (MAPK) inhibitor and the extracellular signal-regulated kinase MAPK inhibitor significantly abrogated IL-8 secretion by B. cepacia-infected HLE cells (SB203580, > or =80% inhibition; PD98059, > or =30% inhibition). In conclusion, B. cepacia-induced IL-8 secretion in A549 airway epithelial cells is more potent than P. aeruginosa; is mediated through LPS, which is CD14 dependent; and involves activation of the p38 and ERK MAPK pathways.

The potential role of peroxisome proliferator-activated receptors on inflammation in type 2 diabetes mellitus and atherosclerosis

Increasing attention has focused on the role of inflammation in various chronic diseases, including atherosclerosis. Recent compelling data have begun to unite work from various arenas, such as epidemiology and vascular biology, and even clinical trials to provide evidence for inflammation as a mechanism underlying cardiovascular disease. Inflammation has been implicated in the pathogenesis, progression, and complications of both atherosclerosis and diabetes mellitus-2 complex disorders often found intertwined in patients. Although this story continues to evolve, peroxisome proliferator-activated receptors (PPARs) have been implicated as a molecular pathway involved in both these disease processes. In vitro data, animal work, and some human studies suggest that synthetic PPAR agonists in clinical use, such as thiazolidinediones, may not only regulate metabolic processes but may also limit inflammatory responses, including some involved in atherosclerosis.

Alpha-defensin 1 (human neutrophil protein 1) as an antichemotactic agent for human polymorphonuclear leukocytes

Medium conditioned by tumor necrosis factor alpha (TNF-alpha)-stimulated polymorphonuclear leukocytes (PMN) (CM-TNF) suppresses PMN migration. Therefore, we wished to identify the agent(s) in CM-TNF that mediated antichemotactic activity. CM-TNF was fractionated by high-performance liquid chromatography, and one fraction with antichemotactic activity contained the bactericidal protein human neutrophil protein 1 (HNP-1). We showed that HNP-1 suppresses PMN migration to formyl-methionyl-leucyl-phenylalanine but not to interleukin 8.