Cell adhesion antagonists: therapeutic potential in asthma and chronic obstructive pulmonary disease

The lung proteome in HIV-associated obstructive lung disease

Rationale

Obstructive lung disease is increasingly common among persons living with HIV (PLWH). There are currently no validated biomarkers that identify individuals at risk of developing obstructive lung disease (OLD), and specific mechanisms contributing to HIV-associated OLD remain elusive, independent of smoking. We sought to identify biomarkers and biological pathways associated with OLD using a broad proteomic approach.

Methods

We performed tandem mass tagging and mass spectrometry (MS) analysis on bronchoalveolar lavage fluid samples from persons living with HIV with OLD (n=26) and without OLD (n=26). We combined untargeted MS with a targeted SomaScan aptamer-based approach. We used Pearson correlation tests to identify associations between each protein and lung function (forced expiratory volume in 1 s (FEV1) % pred). We adjusted for multiple comparisons using a false discovery rate adjustment. Significant proteins were entered into a pathway over-representation analysis. Protein-driven endotypes were constructed using K-means clustering.

Measurements and main results

We identified over 3800 proteins by MS and identified 254 proteins that correlated with FEV1 % pred when we combined the MS and SomaScan proteomes when adjusting for smoking status. Pathway analysis revealed cell adhesion molecules as significant.

Conclusions

Protein expression differs in the lung of PLWH and decreased lung function (FEV1 % pred). Pathway analysis reveals cell adhesion molecules having potentially important roles in this process.

The Molecular Blueprint for Chronic Obstructive Pulmonary Disease (COPD): A New Paradigm for Diagnosis and Therapeutics

The global prevalence of chronic obstructive pulmonary disease (COPD) has increased over the last decade and has emerged as the third leading cause of death worldwide. It is characterized by emphysema with prolonged airflow limitation. COPD patients are more susceptible to COVID-19 and increase the disease severity about four times. The most used drugs to treat it show numerous side effects, including immune suppression and infection. This review discusses a narrative opinion and critical review of COPD. We present different aspects of the disease, from cellular and inflammatory responses to cigarette smoking in COPD and signaling pathways. In addition, we highlighted various risk factors for developing COPD apart from smoking, like occupational exposure, pollutants, genetic factors, gender, etc. After the recent elucidation of the underlying inflammatory signaling pathways in COPD, new molecular targeted drug candidates for COPD are signal-transmitting substances. We further summarize recent developments in biomarker discovery for COPD and its implications for disease diagnosis. In addition, we discuss novel drug targets for COPD that could be explored for drug development and subsequent clinical management of cardiovascular disease and COVID-19, commonly associated with COPD. Our extensive analysis of COPD cause, etiology, diagnosis, and therapeutic will provide a better understanding of the disease and the development of effective therapeutic options. In-depth knowledge of the underlying mechanism will offer deeper insights into identifying novel molecular targets for developing potent therapeutics and biomarkers of disease diagnosis.

Identification of key genes and regulatory networks involved in the Comorbidity of atrial fibrillation and chronic obstructive pulmonary disease

Background

The underlying molecular processes of atrial fibrillation (AF) and chronic obstructive pulmonary disease (COPD) are frequently linked to increased morbidity and mortality when they co-occur. However, their underlying molecular mechanisms are questioned due to their incomplete analysis.

Objective

This study aimed to identify common differentially expressed genes (DEGs) in AF and COPD patients and investigate their potential biological functions and pathways. We hope to complement and update previous research through clearer figure presentation and different bioinformatic analysis methods with different datasets.

Methods

We used statistical analysis to identify DEGs in the expression profiles of AF and COPD patients using datasets from the Gene Expression Omnibus database. To ascertain whether the common DEGs were functionally enriched, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used. In addition, we generated protein‒protein interaction networks and identified significant hub genes. Furthermore, the hub genes were used to analyze transcription factor (TF)-gene interactions and TF-miRNA coregulatory networks, and their expression levels were validated in additional datasets.

Results

We identified a total of 15 DEGs that were upregulated, whereas 36 were downregulated in AF and COPD patients. The DEGs were commonly expressed in both AF and COPD patients, with functional enrichment analysis revealing their involvement in metabolic processes and neuron-to-neuron synapses. We identified significant hub genes, including TGM2, ITPR1, CHL1, ALDOC, RPS3, FBLN2, NDUFS2, ITGA5, CTNNB1, RBP1, CLSTN2, FABP5, EPHA4, LDHA, and HNRNPL, and analyzed their coexpression and biological functions. TF-gene interaction and TF-miRNA coregulatory network analyses revealed the regulatory relationships of the hub genes. Additional datasets were analyzed to validate hub gene expression, and ALDOC, HNRNPL, and NDUFS2 displayed similar processes in AF and COPD patients.

Conclusions

In our study, we demonstrate that metabolic processes and neuron-to-neuron synaptic connections may contribute to the cooccurrence of AF and COPD. The identified hub genes and regulatory networks may act as potential biomarkers and therapeutic targets for these diseases.

Unravelling the Influence of Host Genetic Factors on Malaria Susceptibility in Asian Populations

Malaria is a deadly blood-borne disease caused by a Plasmodium parasite. Infection results in various forms of malaria, including an asymptomatic state, uncomplicated disease, or severe disease. Severe malaria (SM) is particularly prevalent among young children and is a significant cause of mortality. SM is associated with the sequestration of parasitized erythrocytes in the microvasculature of vital host organs, disrupting the normal functioning of the immune system. Although the exact mechanisms of malaria pathogenesis are yet to be fully understood, researchers have been investigating the role of host genetics in determining the severity of the disease and the outcome of infection. The objective of this study is to identify specific host genes that have been examined for their association with malaria in Asian populations and pinpoint those most likely to influence susceptibility. Through an extensive screening process, a total of 982 articles were initially identified, and after careful review, 40 articles discussing 68 genes were included in this review. By constructing a network of protein-protein interactions (PPIs), we identified six key proteins (TNF, IL6, TLR4, IL1β, IL10, and IL8) that exhibited substantial interactions (more than 30 edges), suggesting their potential as significant targets for influencing malaria susceptibility. Notably, these six proteins have been previously identified as crucial components of the immune response, associated with malaria susceptibility, and capable of affecting different clinical forms of the disease. Identifying genes that contribute to malaria susceptibility or resistance holds the promise of enhancing the diagnosis and treatment of this debilitating illness. Such knowledge has the potential to pave the way for more targeted and effective strategies in combating malaria, particularly in Asian populations where controlling Plasmodium vivax is challenging, and India contributes the highest number of cases. By understanding the genetic factors underlying malaria vulnerability, we can develop interventions that are tailored to the specific needs of Asian populations, ultimately leading to better outcomes in the fight against this disease.

Removal of senescent cells reduces the viral load and attenuates pulmonary and systemic inflammation in SARS-CoV-2-infected, aged hamsters

Older age is one of the strongest risk factors for severe COVID-19. In this study, we determined whether age-associated cellular senescence contributes to the severity of experimental COVID-19. Aged golden hamsters accumulate senescent cells in the lungs, and the senolytic drug ABT-263, a BCL-2 inhibitor, depletes these cells at baseline and during SARS-CoV-2 infection. Relative to young hamsters, aged hamsters had a greater viral load during the acute phase of infection and displayed higher levels of sequelae during the post-acute phase. Early treatment with ABT-263 lowered pulmonary viral load in aged (but not young) animals, an effect associated with lower expression of ACE2, the receptor for SARS-CoV-2. ABT-263 treatment also led to lower pulmonary and systemic levels of senescence-associated secretory phenotype factors and to amelioration of early and late lung disease. These data demonstrate the causative role of age-associated pre-existing senescent cells on COVID-19 severity and have clear clinical relevance.

Ether Derivatives of Naringenin and Their Oximes as Factors Modulating Bacterial Adhesion

Because of the close connection between adhesion and many vital cellular functions, the search for new compounds modulating the adhesion of bacteria belonging to the intestinal microbiota is a great challenge and a clinical need. Based on our previous studies, we discovered that O-lkyl naringenin derivatives and their oximes exhibit antimicrobial activity against antibiotic-resistant pathogens. The current study was aimed at determining the modulatory effect of these compounds on the adhesion of selected representatives of the intestinal microbiota: Escherichia coli, a commensal representative of the intestinal microbiota, and Enterococcus faecalis, a bacterium that naturally colonizes the intestines but has disease-promoting potential. To better reflect the variety of real-life scenarios, we performed these studies using two different intestinal cell lines: the physiologically functioning ("healthy") 3T3-L1 cell line and the disease-mimicking, cancerous HT-29 line. The study was performed in vitro under static and microfluidic conditions generated by the Bioflux system. We detected the modulatory effect of the tested O-alkyl naringenin derivatives on bacterial adhesion, which was dependent on the cell line studied and was more significant for E. coli than for E. faecalis. In addition, it was noticed that this activity was affected by the concentration of the tested compound and its structure (length of the carbon chain). In summary, O-alkyl naringenin derivatives and their oximes possess a promising modulatory effect on the adhesion of selected representatives of the intestinal microbiota.

Establishment and application of a high-throughput screening model for cell adhesion inhibitors

The cell adhesion between leukocytes and endothelial cells plays an important balanced role in the pathophysiological function, while excessive adhesion caused by etiological agents is associated with the occurrence and development of many acute and chronic diseases. Cell adhesion inhibitors have been shown to have a potential therapeutic effect on these diseases, therefore, efficient and specific inhibitors against cell adhesion are highly desirable. Here, using lipopolysaccharide-induced human umbilical vein endothelial cells (HUVECs) and calcein-AM-labeled human monocytic cell THP-1, we established a high-throughput screening model for cell adhesion inhibitors with excellent model evaluation parameters. Using the drug repurposing strategy, we screened out lifitegrast, a potent cell adhesion inhibitor, which inhibited cell adhesion between HUVEC and THP-1 cells by directly interrupting the adhesion interaction between HUVEC and THP-1 cells and showed a strong therapeutic effect on the mouse acute liver injury induced by poly (I:C)/D-GalN. Therefore, the screening model is suitable for screening and validating cell adhesion inhibitors, which will promote the research and development of inhibitors for the treatment of diseases caused by excessive cell adhesion.

Molecular Modeling Insights into the Structure and Behavior of Integrins: A Review

Integrins are heterodimeric glycoproteins crucial to the physiology and pathology of many biological functions. As adhesion molecules, they mediate immune cell trafficking, migration, and immunological synapse formation during inflammation and cancer. The recognition of the vital roles of integrins in various diseases revealed their therapeutic potential. Despite the great effort in the last thirty years, up to now, only seven integrin-based drugs have entered the market. Recent progress in deciphering integrin functions, signaling, and interactions with ligands, along with advancement in rational drug design strategies, provide an opportunity to exploit their therapeutic potential and discover novel agents. This review will discuss the molecular modeling methods used in determining integrins' dynamic properties and in providing information toward understanding their properties and function at the atomic level. Then, we will survey the relevant contributions and the current understanding of integrin structure, activation, the binding of essential ligands, and the role of molecular modeling methods in the rational design of antagonists. We will emphasize the role played by molecular modeling methods in progress in these areas and the designing of integrin antagonists.

Emerging therapies targeting eosinophil-mediated inflammation in chronic allergic conjunctivitis

Ocular allergy remains a significant burden to the population while the treatment for the severe, chronic forms of allergic conjunctivitis remains largely limited to non-specific immunosuppressants. Eosinophils are central to the pathophysiology and sustaining the immunologic response found in the chronic forms of ocular allergy such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. Several mediators of eosinophil recruitment, chemotaxis, adhesion, activation, and survival have been identified that offer potential therapeutic targets for ocular allergy. Based on preclinical and clinical data available in both ocular and non-ocular allergy studies, these emerging therapies warrant further investigation in reducing the severity of disease in patients with chronic ocular allergy.

Risk factors of severe COVID-19 in people with multiple sclerosis : A systematic review and meta-analysis

Objectives

To gather, synthesize, and meta-analyze data regarding the risk factors associated with a severe course of COVID-19 among patients with multiple sclerosis (pwMS).

Methods

MEDLINE, Embase, Scopus, and WoS were searched in May 2021. Briefly, the eligibility criteria included: 1) studies assessing COVID-19 severity among adult pwMS; 2) definitive diagnoses or high clinical suspicion of COVID-19; 3) a categorization of COVID-19 severity into at least two categories; 4) quantitative effect size and precision measurements; and 5) English language; and 6) clear effect size/precision measures. internal validity of studies was assessed using the NIH Quality Assessment Tools. A list of possible risk factors was created based on the search results and was later used in extraction, synthesis, and meta-analysis of the data.

Results

Thirteen studies were included in the syntheses. Outcome measures were either extracted from the papers, obtained from the primary researchers or calculated manually. The meta-analyses showed a significantly (P < 0.05) increased odds of a severe COVID-19 in pwMS with all of the assessed risk factors, except smoking and most DMTs.

Conclusion

This study facilitates evidence-based risk/benefit assessments in practice. Older men with progressive MS on anti-CD20 therapies are more at risk of an unfortunate COVID-19 outcome.

Pan-selectin inhibitors as potential therapeutics for COVID-19 treatment: in silico screening study

Coronavirus disease 2019 (COVID-19) has spread rapidly throughout the globe. The spectrum of disease is broad but among hospitalized patients with COVID-19, respiratory failure from acute respiratory distress syndrome is the leading cause of mortality. There is an urgent need for an effective treatment. The current focus has been developing novel therapeutics, including antivirals, protease inhibitors, vaccines and targeting the overactive cytokine response with anti-cytokine therapy. The overproduction of early response proinflammatory cytokines results in what has been described as a "cytokine storm" is leading eventually to death when the cells fail to terminate the inflammatory response. Accumulating evidence shows that inflammatory cytokines induce selectin ligands that play a crucial role in the pathogenesis of inflammatory diseases by mediating leukocyte migration from the blood into the tissue. Thus, the selectins and selectin ligands represent a promising therapeutic target for the treatment of COVID-19. In this paper, potential pan-selectin inhibitors were identified employing a virtual screening using a docking procedure. For this purpose, the Asinex and ZINC databases of ligands, including approved drugs, biogenic compounds and glycomimetics, altogether 923,602 compounds, were screened against the P-, L- and E-selectin. At first, the experimentally confirmed inhibitors were docked into all three selectins' carbohydrate recognition domains to assess the suitability of the screening procedure. Finally, based on the evaluation of ligands binding, we propose 10 purchasable pan-selectin inhibitors to develop COVID-19 therapeutics.

The blocking effect of the glycoprotein IIb/IIIa receptor in the mouse model of asthma

BACKGROUND

It is apparent that the interaction between platelets and eosinophils plays a critical role in the activation of allergic inflammation. We investigated whether blocking of the glycoprotein (GP) IIb/IIIa receptor can attenuate allergic inflammation and airway hyperresponsiveness through inhibition of platelet-eosinophil aggregation (PEA) in asthma.

METHODS

BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) on days 0 and 14, followed by 3 nebulized OVA challenges on days 28-30. On each challenge day, 5 mg/kg tirofiban was administered intraperitoneally 30 min before the challenge. Mice were assessed for airway hyperresponsiveness (AHR), airway inflammation, and the degree of PEA. Finally, the activation levels of platelets and eosinophils were evaluated.

RESULTS

Tirofiban treatment decreased AHR and eosinophilic inflammation in Bronchoalveolar Lavage (BAL) fluid. This treatment also reduced the levels of interleukin (IL)-4, IL-5, and IL-13 in BAL fluid and airway inflammatory cell infiltration in histological evaluation. Interestingly, the blocking of the GP IIb/IIIa receptor more reduced PEA in both blood and lung tissue of tirofiban-treated mice than in those of the positive control mice, and both eosinophilic and platelet activations were attenuated in tirofiban-treated mice.

CONCLUSIONS

The blocking of GP IIb/IIIa receptor with tirofiban can attenuate AHR and airway inflammation through the inhibition of PEA and activation.

Progress in the mechanism and targeted drug therapy for COPD

Chronic obstructive pulmonary disease (COPD) is emphysema and/or chronic bronchitis characterised by long-term breathing problems and poor airflow. The prevalence of COPD has increased over the last decade and the drugs most commonly used to treat it, such as glucocorticoids and bronchodilators, have significant therapeutic effects; however, they also cause side effects, including infection and immunosuppression. Here we reviewed the pathogenesis and progression of COPD and elaborated on the effects and mechanisms of newly developed molecular targeted COPD therapeutic drugs. Among these new drugs, we focussed on thioredoxin (Trx). Trx effectively prevents the progression of COPD by regulating redox status and protease/anti-protease balance, blocking the NF-κB and MAPK signalling pathways, suppressing the activation and migration of inflammatory cells and the production of cytokines, inhibiting the synthesis and the activation of adhesion factors and growth factors, and controlling the cAMP-PKA and PI3K/Akt signalling pathways. The mechanism by which Trx affects COPD is different from glucocorticoid-based mechanisms which regulate the inflammatory reaction in association with suppressing immune responses. In addition, Trx also improves the insensitivity of COPD to steroids by inhibiting the production and internalisation of macrophage migration inhibitory factor (MIF). Taken together, these findings suggest that Trx may be the ideal drug for treating COPD.

Risiken und Chancen von Immuntherapien in Zeiten der Coronavirus-2019-Pandemie

Immuntherapien stellen die essenzielle Grundlage der Behandlung von neuroinflammatorischen Erkrankungen dar. In Zeiten der Coronavirus-2019 (COVID-19)-Pandemie ergibt sich im klinischen Alltag jedoch zunehmend die Frage, ob eine Immuntherapie bei neurologischen Patienten aufgrund des potenziellen Infektionsrisikos eingeleitet, intensiviert, pausiert oder gar beendet werden sollte. Unsicherheit besteht v. a. deshalb, weil verschiedene nationale und internationale Fachgesellschaften diesbezüglich unterschiedliche Empfehlungen veröffentlichten. In diesem Artikel soll ein Überblick über die Wirkmechanismen von Immuntherapien und den daraus abzuleitenden Infektionsrisiken in Bezug auf COVID-19 (durch den Coronavirus verursachte Erkrankung) gegeben werden. Potenzielle Chancen und vorteilhafte Effekte einzelner Substrate in der Akuttherapie von COVID-19 werden diskutiert.

Merits and culprits of immunotherapies for neurological diseases in times of COVID-19

Immunosuppression and immunomodulation are valuable therapeutic approaches for managing neuroimmunological diseases. In times of the Coronavirus disease 2019 (COVID-19) pandemic, clinicians must deal with the question of whether immunotherapy should currently be initiated or discontinued in neurological patients. Uncertainty exists especially because different national medical associations publish different recommendations on the extent to which immunotherapies must be continued, monitored, or possibly switched during the current pandemic. Based on the most recently available data both about the novel coronavirus and the approved immunotherapies for neurological diseases, we provide an updated overview that includes current treatment strategies and the associated COVID-19 risk, but also the potential of immunotherapies to treat COVID-19.

Repositioned Drugs for Inflammatory Diseases such as Sepsis, Asthma, and Atopic Dermatitis

The process of drug discovery and drug development consumes billions of dollars to bring a new drug to the market. Drug development is time consuming and sometimes, the failure rates are high. Thus, the pharmaceutical industry is looking for a better option for new drug discovery. Drug repositioning is a good alternative technology that has demonstrated many advantages over de novo drug development, the most important one being shorter drug development timelines. In the last two decades, drug repositioning has made tremendous impact on drug development technologies. In this review, we focus on the recent advances in drug repositioning technologies and discuss the repositioned drugs used for inflammatory diseases such as sepsis, asthma, and atopic dermatitis.

Pathway centrality in protein interaction networks identifies putative functional mediating pathways in pulmonary disease

Identification of functional pathways mediating molecular responses may lead to better understanding of disease processes and suggest new therapeutic approaches. We introduce a method to detect such mediating functions using topological properties of protein-protein interaction networks. We define the concept of pathway centrality, a measure of communication between disease genes and differentially expressed genes. Using pathway centrality, we identify mediating pathways in three pulmonary diseases (asthma; bronchopulmonary dysplasia (BPD); and chronic obstructive pulmonary disease (COPD)). We systematically evaluate the significance of all identified central pathways using genetic interactions. Mediating pathways shared by all three pulmonary disorders favor innate immune and inflammation-related processes, including toll-like receptor (TLR) signaling, PDGF- and angiotensin-regulated airway remodeling, the JAK-STAT signaling pathway, and interferon gamma. Disease-specific mediators, such as neurodevelopmental processes in BPD or adhesion molecules in COPD, are also highlighted. Some of our findings implicate pathways already in development as drug targets, while others may suggest new therapeutic approaches.

Magnetic Resonance Imaging of Atherosclerotic Plaque at Clinically Relevant Field Strengths (1T) by Targeting the Integrin α4β1

Inflammation drives the degradation of atherosclerotic plaque, yet there are no non-invasive techniques available for imaging overall inflammation in atherosclerotic plaques, especially in the coronary arteries. To address this, we have developed a clinically relevant system to image overall inflammatory cell burden in plaque. Here, we describe a targeted contrast agent (THI0567-targeted liposomal-Gd) that is suitable for magnetic resonance (MR) imaging and binds with high affinity and selectivity to the integrin α4β1(very late antigen-4, VLA-4), a key integrin involved in recruiting inflammatory cells to atherosclerotic plaques. This liposomal contrast agent has a high T1 relaxivity (~2 × 10⁵ mM^-1s^-1 on a particle basis) resulting in the ability to image liposomes at a clinically relevant MR field strength. We were able to visualize atherosclerotic plaques in various regions of the aorta in atherosclerosis-prone ApoE^-/- mice on a 1 Tesla small animal MRI scanner. These enhanced signals corresponded to the accumulation of monocyte/macrophages in the subendothelial layer of atherosclerotic plaques in vivo, whereas non-targeted liposomal nanoparticles did not demonstrate comparable signal enhancement. An inflammatory cell-targeted method that has the specificity and sensitivity to measure the inflammatory burden of a plaque could be used to noninvasively identify patients at risk of an acute ischemic event.

An integrated QSAR modeling approach to explore the structure-property and selectivity relationships of N-benzoyl-L-biphenylalanines as integrin antagonists

Integrins [Formula: see text] and [Formula: see text] are important targets to treat different inflammatory diseases, such as multiple sclerosis, inflammatory bowel diseases, rheumatoid arthritis, atherosclerosis, and asthma. Despite being valuable targets, only a few work has been reported to date regarding molecular modeling studies on these integrins. Not only that, none of these reports addressed the selectivity issue between integrins [Formula: see text] and [Formula: see text]. Therefore, a major challenge regarding the design and discovery of selective integrin antagonists remains. In this study, a series of 142 N-benzoyl-L-biphenylalanines having both integrin [Formula: see text] and [Formula: see text] inhibitory activities were considered for a variety of QSAR approaches including regression and classification-based 2D-QSARs, Hologram QSARs, 3D-QSAR CoMFA and CoMSIA studies to identify the structural requirements of these integrin antagonists. All these QSAR models were statistically validated and subsequently correlated with each other to get a detailed understanding of the activity and selectivity profiles of these molecules.

Cellular crosstalk between airway epithelial and endothelial cells regulates barrier functions during exposure to double-stranded RNA

INTRODUCTION

The epithelial and endothelial barriers of the airway mucosa are critical for regulation of tissue homeostasis and protection against pathogens or other tissue damaging agents. In response to a viral infection, epithelial cells must signal to the endothelium to initiate immune cell recruitment. This is a highly temporal regulated process; however, the mechanisms of this cross-talk are not fully understood.

METHODS

In a close-contact co-culture model of human airway epithelial and endothelial cells, cellular crosstalk was analyzed using transepithelial electrical resistance (TER) measurements, immunofluorescence, electron microscopy, and ELISA. Viral infections were simulated by exposing airway epithelial cells apically to double-stranded RNA (Poly(I:C)). Using a microfluidic culture system, the temporal release of mediators was analyzed in the co-culture model.

RESULTS

Within 4 h of challenge, double-stranded RNA induced the release of TNF-α by epithelial cells. This activated endothelial cells by triggering the release of the chemoattractant CX3CL1 (fractalkine) by 8 h post-challenge and expression of adhesion molecules E-selectin and ICAM-1. These responses were significantly reduced by neutralising TNF-α.

CONCLUSION

By facilitating kinetic profiling, the microfluidic co-culture system has enabled identification of a key signaling mechanism between the epithelial and endothelial barriers. Better understanding of cell-cell cross-talk and its regulatory mechanisms has the potential to identify new therapeutic strategies to control airway inflammation.

8,9-Dehydrohispanolone-15,16-lactol diterpene prevents LPS-triggered inflammatory responses by inhibiting endothelial activation

Endothelial activation contributes to lung inflammatory disorders by inducing leucocyte recruitment to pulmonary parenchyma. Consequently, vascular-targeted therapies constitute promising strategies for the treatment of inflammatory pathologies. In the present study, we evaluated the effect of 8,9-dehydrohispanolone-15,16-lactol diterpene (DT) on lung endothelium during inflammation. Lung endothelial cells pre-treated with DT and activated with lipopolysaccharide (LPS) or tumour necrosis factor-α (TNF-α) exhibited reduced expression of the pro-inflammatory cytokines Cxcl10, Ccl5 and Cxcl1, whereas the anti-inflammatory molecules IL1r2 and IL-10 were induced. Consistent with this result, DT pre-treatment inhibited nuclear factor κB (NF-κB) nuclear translocation, by interfering with IκBα phosphorylation, and consequently NF-κB transcriptional activity in endothelium activated by LPS or TNF-α. Furthermore, DT, probably through p38 signalling, induced transcriptional activation of genes containing activator protein 1 (AP-1)-binding elements. Inhibition of p38 prevented IL1r2 mRNA expression in endothelium incubated with DT alone or in combination with LPS or TNF-α. Accordingly, conditioned medium (CM) from these cells failed to stimulate leucocytes as measured by a reduction in adhesive ability of the leucocyte cell line J774 to fibronectin (FN). Additionally, DT reduced the expression of the endothelial adhesion molecules E-selectin, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) after activation. Similarly, expression of VCAM-1 and ICAM-1 molecules on the lung endothelial layer of C57/BL6 mice pre-treated with DT and challenged with LPS were unchanged. Finally, inhibition of vascular adhesion molecule expression by DT decreased the interaction of J774 cells with lung endothelial cells in an inflammatory environment. Our findings establish DT as a novel endothelial inhibitor for the treatment of inflammatory-related diseases triggered by Gram-negative bacteria or by the associated cytokine TNF-α.

Dissecting asthma pathogenesis through study of patterns of cellular traffic indicative of molecular switches operative in inflammation

Background:

Inflammation and degeneration are the two edged swords that impale a pulmonary system with the maladies like asthma and idiopathic pulmonary fibrosis. To explore critical role players that orchestrate the etiology and pathogenesis of these diseases, we used various lung disease models in mice in specific genetic knockout templates.

Materials and methods:

Acute and chronic allergic asthma and idiopathic pulmonary fibrosis model in mouse was developed in various genetic knockout templates namely α4^{Δ/ Δ}(α41-/-), β2-/-, and α4-/- β2 mice, and the following parameters were measured to assess development of composite asthma phenotype- (i) airway hyperresponsiveness to methacholine by measuring lung resistance and compliance by invasive and P_enh by non-invasive plethysmography as well as lung resistance and compliance using invasive plethysmography, (ii) in situ inflammation status in lung parenchyma and lung interstitium and also resultant airway remodelling measured by histochemical staining namely Masson’s Trichrome staining and Hematoxylin&Eosin staining, (iii) formation of metaplastic goblet cells around lung airways by Alcian blue dye, (iv) measurement of Th1 and Th2 cytokines in serum and bronchoalveolar lavage fluid (BALf), (v) serum allergen-specific IgE. Specifically, ovalbumin-induced acute allergic asthma model in mice was generated in WT (wildtype) and KO (knockout) models and readouts of the composite asthma phenotype viz. airway hypersensitivity, serum OVA-specific IgE and IgG, Th2 cytokine in bronchoalveolar lavage fluid (BALf) and lymphocyte cell subsets viz. T, B cells, monocytes, macrophages, basophils, mast cells and eosinophils (by FACS and morphometry in H&E stained cell smears) were assessed in addition to lung and lymph node histology.

Results:

We noticed a pattern of cellular traffic between bone marrow (BM)→ peripheral blood (PB) → lung parenchyma (LP) → (BALf) in terms of cellular recruitment of key cell sub-types critical for onset and development of the diseases which is different for maintenance and exacerbations in chronic cyclically occurring asthma that leads to airway remodelling. While inflammation is the central theme of this particular disease, degeneration and shift in cellular profile, subtly modifying the clinical nature of the disease were also noted. In addition we recorded the pattern of cell movement between the secondary lymphoid organs namely, the cervical, axillary, ingunal, and mesenteric lymph nodes vis-à-vis spleen and their sites of poiesis BM, PB and lung tissue. While mechanistic role is the chief domain of the integrins (α4 i.e. VLA-4 or α4β1, VCAM-1; β2 i.e. CD18 or ICAM-1).

Concluding remarks:

The present paper thoroughly compares and formulates the pattern of cellular traffic among the three nodes of information throughput in allergic asthma immunobiology, namely, primary lymphoid organs (PLO), secondary lymphoid organs (SLO), and tissue spaces and cells where inflammation and degeneration is occurring within the purview of the disease pathophysiological onset and ancillary signals in the above models and reports some interesting findings with respect to adult lung stem cell niches and its resident progenitors and their role in pathogenesis and disease amelioration.

Attenuation of airway inflammation by simvastatin and the implications for asthma treatment: is the jury still out?

Although some studies have explained the immunomodulatory effects of statins, the exact mechanisms and the therapeutic significance of these molecules remain to be elucidated. This study not only evaluated the therapeutic potential and inhibitory mechanism of simvastatin in an ovalbumin (OVA)-specific asthma model in mice but also sought to clarify the future directions indicated by previous studies through a thorough review of the literature. BALB/c mice were sensitized to OVA and then administered three OVA challenges. On each challenge day, 40 mg kg⁻¹ simvastatin was injected before the challenge. The airway responsiveness, inflammatory cell composition, and cytokine levels in bronchoalveolar lavage (BAL) fluid were assessed after the final challenge, and the T cell composition and adhesion molecule expression in lung homogenates were determined. The administration of simvastatin decreased the airway responsiveness, the number of airway inflammatory cells, and the interleukin (IL)-4, IL-5 and IL-13 concentrations in BAL fluid compared with vehicle-treated mice (P<0.05). Histologically, the number of inflammatory cells and mucus-containing goblet cells in lung tissues also decreased in the simvastatin-treated mice. Flow cytometry showed that simvastatin treatment significantly reduced the percentage of pulmonary CD4⁺ cells and the CD4⁺/CD8⁺ T-cell ratio (P<0.05). Simvastatin treatment also decreased the expression of the vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 proteins, as measured in homogenized lung tissues (P<0.05) and human epithelial cells. The reduction in the T cell influx as a result of the decreased expression of cell adhesion molecules is one of the mechanisms by which simvastatin attenuates airway responsiveness and allergic inflammation. Rigorous review of the literature together with our findings suggested that simvastatin should be further developed as a potential therapeutic strategy for allergic asthma.

Role of integrin alpha4 in drug resistance of leukemia

Chemotherapeutic drug resistance in acute lymphoblastic leukemia (ALL) is a significant problem, resulting in poor responsiveness to first-line treatment or relapse after transient remission. Classical anti-leukemic drugs are non-specific cell cycle poisons; some more modern drugs target oncogenic pathways in leukemia cells, although in ALL these do not play a very significant role. By contrast, the molecular interactions between microenvironment and leukemia cells are often neglected in the design of novel therapies against drug resistant leukemia. It was shown however, that chemotherapy resistance is promoted in part through cell–cell contact of leukemia cells with bone marrow (BM) stromal cells, also called cell adhesion-mediated drug resistance (CAM-DR). Incomplete response to chemotherapy results in persistence of resistant clones with or without detectable minimal residual disease (MRD). Approaches for how to address CAM-DR and MRD remain elusive. Specifically, studies using anti-functional antibodies and genetic models have identified integrin alpha4 as a critical molecule regulating BM homing and active retention of normal and leukemic cells. Pre-clinical evidence has been provided that interference with alpha4-mediated adhesion of ALL cells can sensitize them to chemotherapy and thus facilitate eradication of ALL cells in an MRD setting. To this end, Andreeff and colleagues recently provided evidence of stroma-induced and alpha4-mediated nuclear factor-κB signaling in leukemia cells, disruption of which depletes leukemia cells of strong survival signals. We here review the available evidence supporting the targeting of alpha4 as a novel strategy for treatment of drug resistant leukemia.

Therapeutic targeting of eosinophil adhesion and accumulation in allergic conjunctivitis

Considerable evidence indicates that eosinophils are important effectors of ocular allergy. Increased worldwide prevalence of allergic eye pathologies has stimulated the identification of novel drug targets, including eosinophils and adhesion molecules. Accumulation of eosinophils in the eye is a key event in the onset and maintenance of allergic inflammation and is mediated by different adhesion molecules. Antihistamines with multiple mechanisms of action can be effective during the early and late phases of allergic conjunctivitis by blocking the interaction between β(1) integrins and vascular cell adhesion molecule (VCAM)-1. Small molecule antagonists that target key elements in the process of eosinophil recruitment have been identified and reinforce the validity of α(4)β(1) integrin as a therapeutic target. Glucocorticoids are among the most effective drugs for ocular allergy, but their use is limited by adverse effects. Novel dissociated glucocorticoids can prevent eosinophil accumulation and induce apoptosis of eosinophils, making them promising candidates for ophthalmic drugs. This article reviews recent understanding of the role of adhesion molecules in eosinophil recruitment in the inflamed conjunctiva along with effective treatments for allergic conjunctivitis.

[Treatment of distal airways involvement in COPD]

INTRODUCTION

The current pharmacological treatment of COPD provides only partial beneficial effects on symptoms, exercise tolerance, frequency of exacerbations and quality of life. This could be related to poor targeting of the distal airways by current treatments, yet these airways are particularly involved in airflow obstruction and its consequences such as hyperinflation.

BACKGROUND

Many treatments used in COPD could have effects on distal airways, including bronchodilators, corticosteroids, mucolytics and antibiotics. However, these possible effects remain poorly understood.

VIEWPOINTS

New treatments targeting more specifically the mechanisms of inflammation, oxidative stress and tissue remodeling that characterize COPD, could prove useful in its management, but most are still only in the early stages of their development. Advances could also come from improvements in inhalation devices, delivering more of the medication to the distal airways.

CONCLUSIONS

Improvement in the management of COPD could come from progress in terms of both molecules and their mode of administration.

Triple selectin knockout (ELP-/-) mice fail to develop OVA-induced acute asthma phenotype

OBJECTIVE

The recruitment of leukocytes from circulation to sites of inflammation requires several families of adhesion molecules among which are selectins expressed on a variety of cells. In addition, they have also been shown to play key roles in the activation of cells in inflammation.

METHODS

To explore the collective role of E-, L-, and P- selectins in OVA-induced Th2 mediated response in acute asthma pathophysiology, ELP-/- mice were used and compared with age-matched wildtype (WT).

RESULTS

Asthma phenotype was assessed by measuring pulmonary function, inflammation and OVA-specific serum IgE, which were completely abrogated in ELP-/- mice. Adoptive transfer of sensitized L selectin+CD4+ T cells into naïve ELP-/- mice which post-OVA challenge, developed asthma, suggesting that L-selectin may be critically involved in the onset of Th2 response in asthma. Tissue resident ELP-deficient cells were otherwise functionally competent as proved by normal proliferative response.

CONCLUSIONS

Comparative studies between ELP-/- and WT mice uncovered functional roles of these three integrins in inflammatory response in allergic asthma. All three selectins seem to impede inflammatory migration while only L-selectin also possibly regulates activation of specific T cell subsets in lung and airways.

Animal models of asthma: value, limitations and opportunities for alternative approaches

Asthma remains an area of considerable unmet medical need. Few new drugs have made it to the clinic during the past 50 years, with many that perform well in preclinical animal models of asthma, failing in humans owing to lack of safety and efficacy. The failure to translate promising drug candidates from animal models to humans has led to questions about the utility of in vivo studies and to demand for more predictive models and tools based on the latest technologies. Following a workshop with experts from academia and the pharmaceutical industry, we suggest here a disease modelling framework designed to better understand human asthma, and accelerate the development of safe and efficacious new asthma drugs that go beyond symptomatic relief.

Discovery of potential integrin VLA-4 antagonists using pharmacophore modeling, virtual screening and molecular docking studies

Very late antigen-4 (VLA-4) is an integrin protein, and its antagonists are useful as anti-inflammatory drugs. The aim of this study is to discover novel virtual lead compounds to use them in designing potent VLA-4 antagonists. A best pharmacophore model was generated with correlation coefficient of 0.935, large cost difference of 114.078, comprising two hydrogen bond acceptors and three hydrophobic features. It was further validated and used in database screening for potential VLA-4 antagonists. A homology model of VLA-4 was built and employed in molecular docking of screened hit compounds. Finally, two compounds were identified as potential virtual leads to be deployed in the designing of novel potent VLA-4 antagonists.

Discovery of very late antigen-4 (VLA-4, alpha4beta1 integrin) allosteric antagonists

Integrins are cell adhesion receptors that mediate cell-to-cell, or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1, lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro, the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood, we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100, a well known progenitor mobilizing agent. Because all the identified compounds are structurally related, previously used, or currently marketed drugs, this result opens a range of therapeutic possibilities for VLA-4-related pathologies.

Adhesion molecules: key players in Mesenchymal stem cell-mediated immunosuppression

Adhesion molecules are known to be important components of an active T cell-mediated immune response. Signals generated at a site of inflammation cause circulating T-cells to respond by rolling, arrest, and then transmigration through the endothelium, all of which are mediated by adhesion molecules. Consequently, strategies have been developed to treat immune disorders with specific antibodies that block the interaction of adhesion molecules. However, the therapeutic effects of such remedies are not always achieved. Our recent investigations have revealed that intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) work together with chemokines to induce immunosuppression mediated by mesenchymal stem cells (MSCs), thus demonstrating the dual role of adhesion molecules in immune responses. Since MSCs represent an important component of the stromal cells in an inflammatory microenvironment, our findings provide novel information for understanding the regulation of immune responses and for designing new strategies to treat immune disorders.

Continuous infusion of UHMWPE particles induces increased bone macrophages and osteolysis

BACKGROUND

Aseptic loosening and periprosthetic osteolysis resulting from wear debris are major complications of total joint arthroplasty. Monocyte/macrophages are the key cells related to osteolysis at the bone-implant interface of joint arthroplasties. Whether the monocyte/macrophages found at the implant interface in the presence of polyethylene particles are locally or systemically derived is unknown.

QUESTIONS/PURPOSES

We therefore asked (1) whether macrophages associated with polyethylene particle-induced chronic inflammation are recruited locally or systemically and (2) whether the recruited macrophages are associated with enhanced osteolysis locally.

METHODS

Noninvasive in vivo imaging techniques (bioluminescence and microCT) were used to investigate initial macrophage migration systemically from a remote injection site to polyethylene wear particles continuously infused into the femoral canal. We used histologic and immunohistologic staining to confirm localization of migrated macrophages to the polyethylene particle-treated femoral canals and monitor cellular markers of bone remodeling.

RESULTS

The values for bioluminescence were increased for animals receiving UHMWPE particles compared with the group in which the carrier saline was infused. At Day 8, the ratio of bioluminescence (operated femur divided by nonoperated contralateral femur of each animal) for the UHMWPE group was 13.95 ± 5.65, whereas the ratio for the saline group was 2.60 ± 1.14. Immunohistologic analysis demonstrated the presence of reporter macrophages in the UHMWPE particle-implanted femora only. MicroCT scans showed the bone mineral density for the group with both UHMWPE particles and macrophage was lower than the control groups.

CONCLUSIONS

Infusion of clinically relevant polyethylene particles, similar to the human scenario, stimulated systemic migration of remotely injected macrophages and local net bone resorption.

The contribution of L-selectin to airway hyperresponsiveness in chronic allergic airways disease

L-selectin is a cell adhesion molecule, which mediates leukocyte rolling on bronchopulmonary endothelium. Previous studies in a murine model of allergic airways disease have shown that L-selectin plays a role in the regulation of airway hyperresponsiveness in asthma via mechanisms independent of inflammation. Airway remodeling has been shown to modulate airway hyperresponsiveness independently of inflammation.

New therapies for asthma: is there any progress?

Current therapy for asthma with inhaled corticosteroids and long-acting inhaled beta(2)-agonists is highly effective, safe and relatively inexpensive, but for many patients, their disease remains poorly controlled. Most advances in asthma therapy have occurred through improving these drug classes, and a major developmental hurdle is to improve existing drug classes. The major unmet needs include better treatment of severe asthma, and curative therapies for mild to moderate asthma. Many new treatments are specific, targeting a single mediator or receptor, and are unlikely to have a major clinical effect, although they might be effective in specific asthma phenotypes. Drugs with more widespread effects, such as kinase inhibitors, might be more effective but have a greater risk of side effects. New treatments targeting the underlying allergic/immune process would treat concomitant allergic diseases. Improved immunotherapy approaches have the prospect of disease modification, although prospects for a cure are currently remote. The most promising therapeutic developments for asthma are discussed in this review.

The integrin-blocking peptide RGDS inhibits airway smooth muscle remodeling in a guinea pig model of allergic asthma

RATIONALE

Airway remodeling, including increased airway smooth muscle (ASM) mass and contractility, contributes to airway hyperresponsiveness in asthma. The mechanisms driving these changes are, however, incompletely understood. Recently, an important role for extracellular matrix proteins in regulating ASM proliferation and contractility has been found, suggesting that matrix proteins and their integrins actively modulate airway remodeling.

OBJECTIVES

To investigate the role of RGD (Arg-Gly-Asp)-binding integrins in airway remodeling in an animal model of allergic asthma.

METHODS

Using a guinea pig model of allergic asthma, the effects of topical application of the integrin-blocking peptide RGDS (Arg-Gly-Asp-Ser) and its negative control GRADSP (Gly-Arg-Ala-Asp-Ser-Pro) were assessed on markers of ASM remodeling, fibrosis, and inflammation induced by repeated allergen challenge. In addition, effects of these peptides on human ASM proliferation and maturation were investigated in vitro.

MEASUREMENTS AND MAIN RESULTS

RGDS attenuated allergen-induced ASM hyperplasia and hypercontractility as well as increased pulmonary expression of smooth muscle myosin heavy chain and the proliferative marker proliferating cell nuclear antigen (PCNA). No effects were observed for GRADSP. The RGDS effects were ASM selective, as allergen-induced eosinophil and neutrophil infiltration as well as fibrosis were unaffected. In cultured human ASM cells, we demonstrated that proliferation induced by collagen I, fibronectin, serum, and platelet-derived growth factor requires signaling via RGD-binding integrins, particularly of the alpha(5)beta(1) subtype. In addition, RGDS inhibited smooth muscle alpha-actin accumulation in serum-deprived ASM cells.

CONCLUSIONS

This is the first study indicating that integrins modulate ASM remodeling in an animal model of allergic asthma, which can be inhibited by a small peptide containing the RGD motif.

Fluorinated per-acetylated GalNAc metabolically alters glycan structures on leukocyte PSGL-1 and reduces cell binding to selectins

Novel strategies to control the binding of adhesion molecules belonging to the selectin family are required for the treatment of inflammatory diseases. We tested the possibility that synthetic monosaccharide analogs can compete with naturally occurring sugars to alter the O-glycan content on human leukocyte cell surface selectin-ligand, P-selectin glycoprotein ligand-1 (PSGL-1). Resulting reduction in the sialyl Lewis-X-bearing epitopes on this ligand may reduce cell adhesion. Consistent with this hypothesis, 50muM per-acetylated 4F-GalNAc added to the growth media of promyelocytic HL-60 cells reduced the expression of the cutaneous lymphocyte associated-antigen (HECA-452 epitope) by 82% within 2 cell doubling cycles. Cell binding to all 3 selectins (L-, E-, and P-selectin) was reduced in vitro. 4F-GalNAc was metabolically incorporated into PSGL-1, and this was accompanied by an approximately 20% reduction in PSGL-1 glycan content. A 70% to 85% reduction in HECA-452 binding epitope and N-acetyl lactosamine content in PSGL-1 was also noted on 4F-GalNAc addition. Intravenous 4F-GalNAc infusion reduced leukocyte migration to the peritoneum in a murine model of thioglycolate-induced peritonitis. Thus, the compound has pharmacologic activity. Overall, the data suggest that 4F-GalNAc may be applied as a metabolic inhibitor to reduce O-linked glycosylation, sialyl Lewis-X formation, and leukocyte adhesion via the selectins.

Conformational mAb as a tool for integrin ligand discovery

alpha(4)beta(1)-Integrin (very late antigen-4 (VLA-4)) mediates cell adhesion to cell surface ligands (VCAM-1). Binding of VLA-4 to VCAM-1 initiates rolling and firm adhesion of leukocytes to vascular endothelium followed by the extravasation into the tissue. VLA-4-dependent adhesion plays a key role in controlling leukocyte adhesive events. Small molecules that bind to the integrin ligand-binding site and block its interaction with natural ligands represent promising candidates for treatment of several diseases. Following a flow cytometric screen for small molecule discovery, we took advantage of a conformationally sensitive anti-beta(1)-integrin antibody (HUTS-21) and a small LDV-containing ligand (LDV-FITC) with known affinity to study binding affinities of several known and recently discovered integrin ligands. We found that binding of the LDV-containing small molecule induced exposure of HUTS-21 epitope and that the EC(50) for antibody binding was equal to previously reported K(d) for fluorescent LDV (LDV-FITC). Thus, binding of HUTS-21 can be used to report ligand-binding site occupancy. We studied binding of two known integrin ligands (YLDV and TR14035), as well as of two novel compounds. EC(50) values for HUTS-21 binding showed good correlation with K(i)s determined in the competition assay with LDV-FITC for all ligands. A docking model suggests a common mode of binding for the small molecule VLA-4 ligands. This novel approach described here can be used to determine ligand-binding affinities for unlabeled integrin ligands, and can be adapted to a high-throughput screening format for identification of unknown integrin ligands.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 November 2007 and 31 October 2008 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

Role of inflammation (leukocyte-endothelial cell interactions) in vasospasm after subarachnoid hemorrhage

BACKGROUND

Delayed vasospasm is the leading cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). This phenomenon was first described more than 50 years ago, but only recently has the role of inflammation in this condition become better understood.

METHODS

The literature was reviewed for studies on delayed vasospasm and inflammation.

RESULTS

There is increasing evidence that inflammation and, more specifically, leukocyte-endothelial cell interactions play a critical role in the pathogenesis of vasospasm after aSAH, as well as in other conditions including meningitis and traumatic brain injury. Although earlier clinical observations and indirect experimental evidence suggested an association between inflammation and chronic vasospasm, recently direct molecular evidence demonstrates the central role of leukocyte-endothelial cell interactions in the development of chronic vasospasm. This evidence shows in both clinical and experimental studies that cell adhesion molecules (CAMs) are up-regulated in the perivasospasm period. Moreover, the use of monoclonal antibodies against these CAMs, as well as drugs that decrease the expression of CAMs, decreases vasospasm in experimental studies. It also appears that certain individuals are genetically predisposed to a severe inflammatory response after aSAH based on their haptoglobin genotype, which in turn predisposes them to develop clinically symptomatic vasospasm.

CONCLUSION

Based on this evidence, leukocyte-endothelial cell interactions appear to be the root cause of chronic vasospasm. This hypothesis predicts many surprising features of vasospasm and explains apparently unrelated phenomena observed in aSAH patients. Therapies aimed at preventing inflammation may prevent and/or reverse arterial narrowing in patients with aSAH and result in improved outcomes.

Extracellular matrix molecules: potential targets in pharmacotherapy

The extracellular matrix (ECM) consists of numerous macromolecules classified traditionally into collagens, elastin, and microfibrillar proteins, proteoglycans including hyaluronan, and noncollagenous glycoproteins. In addition to being necessary structural components, ECM molecules exhibit important functional roles in the control of key cellular events such as adhesion, migration, proliferation, differentiation, and survival. Any structural inherited or acquired defect and/or metabolic disturbance in the ECM may cause cellular and tissue alterations that can lead to the development or progression of disease. Consequently, ECM molecules are important targets for pharmacotherapy. Specific agents that prevent the excess accumulation of ECM molecules in the vascular system, liver, kidney, skin, and lung; alternatively, agents that inhibit the degradation of the ECM in degenerative diseases such as osteoarthritis would be clinically beneficial. Unfortunately, until recently, the ECM in drug discovery has been largely ignored. However, several of today's drugs that act on various primary targets affect the ECM as a byproduct of the drugs' actions, and this activity may in part be beneficial to the drugs' disease-modifying properties. In the future, agents and compounds targeting directly the ECM will significantly advance the treatment of various human diseases, even those for which efficient therapies are not yet available.

Emerging drugs for asthma

BACKGROUND

Current therapies for asthma are aimed at controlling disease symptoms and for the majority of asthmatics inhaled corticosteroid anti-inflammatory therapy is effective. However, this approach requires life-time therapy while a subset of patients remains symptomatic despite optimal treatment creating a clear unmet medical need.

OBJECTIVES

It is recognised that airway inflammation is key to asthma pathogenesis. Biopharmaceutical approaches may identify new therapies that target key cells and mediators that drive the inflammatory responses in the asthmatic lung. Such an approach may provide disease-modifying treatments.

RESULTS

Significant areas of drug development include humanised monoclonal antibodies (mAb) for asthma therapy including those against IgE, IL-4 and IL-5. Asthma-relevant cytokines or chemokines have been targeted in a number of other ways. These include the use of humanised receptor blocking mAb or the removal of cytokines or chemokines via their binding to soluble receptor constructs. Small-molecule receptor antagonists also target receptors or the cellular signal transduction pathways that are activated following cytokine or chemokine receptor ligation. Another approach is to target asthma relevant mediators or the pathways controlling pro-inflammatory leukocyte accumulation within the asthmatic lung.

CONCLUSIONS

This review will discuss the current status, therapeutic potential and potential problems of these novel drug developments in asthma therapy. Current therapies for asthma are aimed at controlling disease symptoms, and for the majority of asthmatics inhaled corticosteroid anti-inflammatory therapy is effective. However, this approach requires lifetime therapy; and a subset of patients remains symptomatic despite optimal treatment, creating a clear unmet medical need. It is recognised that airway inflammation is key to asthma pathogenesis. Biopharmaceutical approaches may identify new therapies that target key cells and mediators that drive the inflammatory responses in the asthmatic lung. Such an approach may provide disease-modifying treatments. Significant areas of drug development include humanised mAb for asthma therapy, including those against IgE, IL-4 and IL-5. Asthma-relevant cytokines or chemokines have been targeted in a number of other ways. These include the use of humanised receptor blocking mAb or the removal of cytokines or chemokines via their binding to soluble receptor constructs. Small-molecule receptor antagonists also target receptors or the cellular signal transduction pathways that are activated following cytokine or chemokine receptor ligation. Another approach is to target asthma-relevant mediators, or the pathways controlling pro-inflammatory leukocyte accumulation within the asthmatic lung. This review will discuss the current status, therapeutic potential and potential problems of these novel drug developments in asthma therapy.

Delivery strategies to target therapies to inflammatory tissue

BACKGROUND

Inflammation plays a key role in many chronic disease processes as well as an acute role in injury and wound healing. Various cell types are recruited from the bloodstream to the inflamed site through adhesion molecules, cytokines, chemokines and others.

OBJECTIVES

This review examines many drug-targeting strategies that make use of these molecules or signaling pathways, and seeks to describe certain commonalities irrespective of the disease process or agent to be delivered.

METHODS

A survey of the literature, primarily within the last year, was performed. Search words included 'drug targeting' and 'inflammation' and of those, the scope was refined to include those studies that specifically sought to modify or ameliorate an aspect of the inflammatory process in the treatment of a disease.

RESULTS/CONCLUSION

Inflammation plays a key role in many diseases, and many similar targets (such as adhesion molecules) are the focus of the treatment of those diseases.