Des-aspartate-angiotensin I exerts antiviral effects and attenuates ICAM-1 formation in rhinovirus-infected epithelial cells

Angiotensin II and dengue

Dengue is a disease caused by a flavivirus that is transmitted principally by the bite of an Aedes aegypti mosquito and represents a major public-health problem. Many studies have been carried out to identify soluble factors that are involved in the pathogenesis of this infection. Cytokines, soluble factors, and oxidative stress have been reported to be involved in the development of severe disease. Angiotensin II (Ang II) is a hormone with the ability to induce the production of cytokines and soluble factors related to the inflammatory processes and coagulation disorders observed in dengue. However, a direct involvement of Ang II in this disease has not been demonstrated. This review primarily summarizes the pathophysiology of dengue, the role of Ang II in various diseases, and reports that are highly suggestive of the involvement of this hormone in dengue.

In Vitro Model of Fully Differentiated Human Nasal Epithelial Cells Infected With Rhinovirus Reveals Epithelium-Initiated Immune Responses

Human rhinoviruses (HRVs) are the commonest cause of the common cold. While HRV is less pathogenic than other respiratory viruses, it is frequently associated with exacerbation of chronic respiratory diseases such as rhinosinusitis and asthma. Nasal epithelial cells are the first sites of viral contact, immune initiation, and airway interconnectivity, but there are limited studies on HRV infection of nasal epithelial cells. Hence, we established a model of HRV infection of in vitro-differentiated human nasal epithelial cells (hNECs) derived from multiple individuals. Through HRV infection of hNECs, we found that HRV mainly targeted ciliated cells and preferentially induced type I and III interferon antiviral pathways. Quantitative polymerase chain reaction analysis of inflammatory genes suggested predominant type 1 immunity signaling and recruitment, with secreted CXCL9, IP-10, CXCL11, and RANTES as likely initiators of airway inflammatory responses. Additionally, we further explored HRV bidirectional release from the hNECs and identified 11 associated genes. Other HRV interactions were also identified through a systematic comparison with influenza A virus infection of hNECs. Overall, this in vitro hNEC HRV infection model provides a platform for repeatable and controlled studies of different individuals, thus providing novel insights into the roles of human nasal epithelium in HRV interaction and immune initiation.

Recent advances from studies on the role of structural proteins in enterovirus infection

Enteroviruses are a large group of small nonenveloped viruses that cause common and debilitating illnesses affecting humans and animals worldwide. The capsid composed by viral structural proteins packs the RNA genome. It is becoming apparent that structural proteins of enteroviruses play versatile roles in the virus–host interaction in the viral life cycle, more than just a shell. Furthermore, structural proteins to some extent may be associated with viral virulence and pathogenesis. Better understanding the roles of structural proteins in enterovirus infection may lead to the development of potential antiviral strategies. Here, we discuss recent advances from studies on the role of structural proteins in enterovirus infection and antiviral therapeutics targeted structural proteins.

Losartan and enalapril decrease viral absorption and interleukin 1 beta production by macrophages in an experimental dengue virus infection

The role of angiotensin II (Ang II) in dengue virus infection remains unknown. The aim of this study was to determine the effect of losartan, an antagonist of the angiotensin II type 1 receptor (AT1 receptor), and enalapril, an inhibitor of angiotensin I-converting enzyme (ACE), on viral antigen expression and IL-1β production in peritoneal macrophages infected with dengue virus type 2. Mice treated with losartan or enalapril and untreated controls were infected intraperitoneally with the virus, and macrophages were analyzed. Infection resulted in increased IL-1β production and a high percentage of cells expressing viral antigen, and this was decreased by treatment with anti-Ang II drugs, suggesting a role for Ang II in dengue virus infection.

Des-aspartate-angiotensin I, a novel angiotensin AT(1) receptor drug

The review describes DAA-I (des-aspartate-angiotensin-I) as a prototype of a novel class of drugs that acts as agonists on the angiotensin AT1 receptor or ARAs (angiotensin receptor agonists). DAA-I is a component of the renin angiotensin system. Earlier studies showed that it was rapidly metabolized to angiotensin III. However, when administered at doses below the Km of enzymes, DAA-I produces specific actions that antagonize the deleterious actions of angiotensin II. DAA-I exerts protective actions in animal models of eight human pathologies in which angiotensin II is implicated. The pathologies include cardiac hypertrophy, neointima growth and cardiovascular hypertrophy, myocardial-ischemia reperfusion injury, hyperglycemia and insulin resistance, chemical induced inflammation, and exercise-induced skeletal muscle inflammation. Binding of DAA-I to the angiotensin AT1 receptors releases prostaglandins, which could either function as autocrines/paracrines or second messengers and attenuate the deleterious actions of angiotensin II. It is possible that in in vivo DAA-I functions as a physiological antagonist to angiotensin II, and exogenous DAA-I is a novel class of angiotensin receptor drug that could rival the angiotensin receptor blockers.

Magnolol inhibits tumor necrosis factor-α-induced ICAM-1 expression via suppressing NF-κB and MAPK signaling pathways in human lung epithelial cells

Magnolol is a traditional Chinese medicine from the root and bark of Magnolia officinalis. It has long been used to treat anxiety, cough, headache and allergies, as well as a variety of inflammations. Lung inflammation is a key event in the pathogenesis of asthma and chronic obstructive pulmonary disease. The present study sought to examine the effects of magnolol on tumor necrosis factor (TNF)-α-induced upregulation of intercellular adhesion molecule-1 (ICAM-1), activation of the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathway in cultured human pulmonary epithelial cells, and adhesion of human macrophage-like U937 cells to A549 cells. A549 cells were incubated with magnolol at 25 and 50 μmol/l. Then, 20 ng/ml TNF-α was used to activate the cells. Magnolol inhibited the growth of human pulmonary epithelial A549 cells in a dose- and time-dependent manner. Magnolol suppressed the adhesion of U937 cells to TNF-α-induced A549 cells. In cultured human pulmonary epithelial A549 cells, magnolol decreased TNF-α-induced upregulation of ICAM-1. Magnolol repressed TNF-α-induced activation of NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways in A549 cells by inhibiting phosphorylation of NF-κB, p38, extracellular signal-regulated kinase (ERK) 1/2, and stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK). These findings support the hypothesis that magnolol inhibits the inflammatory process in lung epithelial A549 cells by suppressing the ICAM-1 and NF-κB and MAPK signaling pathways. Taken together, these results indicate that magnolol offers significant potential as a therapeutic treatment for inflammatory diseases of the lungs including asthma, sepsis, and chronic obstructive pulmonary disease.

Intercellular adhesion molecule-1 as a drug target in asthma and rhinitis

Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein receptor of the immunoglobulin superfamily. Endothelial cells, epithelial cells, leukocytes and neutrophils are the major cells expressing ICAM-1. Ligands of ICAM-1 are macrophage adhesion ligand-1, leukocyte function-associated antigen-1 and fibrinogen (extracellular matrix protein). In normal physiological conditions, engagement of ICAM-1 receptor with immunological cells surface ligands assists in homing and trafficking of inflammatory cells to distant tissues. ICAM-1 has also long been known to mediate cell-to-cell interaction during antigen presentation and outside-in cell signalling pathways. ICAM-1-mediated elevated inflammation is implicated in asthma. On respiratory epithelial cells surface, ICAM-1 acts as natural binding site for human rhinovirus (HRV), a common cold virus that ultimately causes exacerbation of asthma. This review presents the findings on the role of ICAM-1 in the complication of asthma and in particular asthma exacerbation by HRV.