Cortactin mediates elevated shear stress-induced mucin hypersecretion via actin polymerization in human airway epithelial cells

Mucus hypersecretion is a remarkable pathophysiological manifestation in airway obstructive diseases. These diseases are usually accompanied with elevated shear stress due to bronchoconstriction. Previous studies have reported that shear stress induces mucin5AC (MUC5AC) secretion via actin polymerization in cultured nasal epithelial cells. Furthermore, it is well known that cortactin, an actin binding protein, is a central mediator of actin polymerization. Therefore, we hypothesized that cortactin participates in MUC5AC hypersecretion induced by elevated shear stress via actin polymerization in cultured human airway epithelial cells. Compared with the relevant control groups, Src phosphorylation, cortactin phosphorylation, actin polymerization and MUC5AC secretion were significantly increased after exposure to elevated shear stress. Similar effects were found when pretreating the cells with jasplakinolide, and transfecting with wild-type cortactin. However, these effects were significantly attenuated by pretreating with Src inhibitor, cytochalasin D or transfecting cells with the specific small interfering RNA of cortactin. Collectively, these results suggest that elevated shear stress induces MUC5AC hypersecretion via tyrosine-phosphorylated cortactin-associated actin polymerization in cultured human airway epithelial cells.     

Sphingosine-1-phosphate: A Janus-faced mediator of fibrotic diseases

Sphingosine-1-phosphate (S1P) is a pleiotropic lipid mediator that acts either on G protein-coupled S1P receptors on the cell surface or via intracellular target sites. In addition to the well established effects of S1P in angiogenesis, carcinogenesis and immunity, evidence is now continuously accumulating which demonstrates that S1P is an important regulator of fibrosis. The contribution of S1P to fibrosis is of a Janus-faced nature as S1P exhibits both pro- and anti-fibrotic effects depending on its site of action. Extracellular S1P promotes fibrotic processes in a S1P receptor-dependent manner, whereas intracellular S1P has an opposite effect and dampens a fibrotic reaction by yet unidentified mechanisms. Fibrosis is a result of chronic irritation by various factors and is defined by an excess production of extracellular matrix leading to tissue scarring and organ dysfunction. In this review, we highlight the general effects of extracellular and intracellular S1P on the multistep cascade of pathological fibrogenesis including tissue injury, inflammation and the action of pro-fibrotic cytokines that stimulate ECM production and deposition. In a second part we summarize the current knowledge about the involvement of S1P signaling in the development of organ fibrosis of the lung, kidney, liver, heart and skin. Altogether, it is becoming clear that targeting the sphingosine kinase-1/S1P signaling pathway offers therapeutic potential in the treatment of various fibrotic processes. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.     

Matrix metalloproteinase (MMP)-2 and MMP-9 polymorphisms and haplotypes as disease biomarkers

Chaudhary and colleagues observed associations of matrix metalloproteinase (MMP)-2 (-1306C/T) and MMP-9 (-1562C/T) promoter polymorphisms with head and neck squamous cell carcinoma (HNSCC), but not with oral submucous fibrosis (OSMF) in an Indian population. We suggest that they could carry out a haplotype analysis with their data on MMP-2 genotypes (-1306C/T and -168G/T) and that they consider genotyping the microsatellite -90 (CA)_14–24 in the MMP-9 promoter region in order to perform haplotype analysis in combination with their data on MMP-9 (-1562C/T) polymorphism. These suggestions could provide additional information with clinical relevance to cancer susceptibility.     

Abnormal exhaled ethane concentrations in scleroderma

Abstract

Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml^–1 CO₂ (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml^?1 CO₂ (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=?2.8, p=0.026, CI=?5.2 to ?0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.     

Interferon Induced IFIT Family Genes in Host Antiviral Defense

Secretion of interferons (IFNs) from virus-infected cells is a hallmark of host antiviral immunity and in fact, IFNs exert their antiviral activities through the induction of antiviral proteins. The IFN-induced protein with tetratricopeptide repeats (IFITs) family is among hundreds of IFN-stimulated genes. This family contains a cluster of duplicated loci. Most mammals have IFIT1, IFIT2, IFIT3 and IFIT5; however, bird, marsupial, frog and fish have only IFIT5. Regardless of species, IFIT5 is always adjacent to SLC16A12. IFIT family genes are predominantly induced by type I and type III interferons and are regulated by the pattern recognition and the JAK-STAT signaling pathway. IFIT family proteins are involved in many processes in response to viral infection. However, some viruses can escape the antiviral functions of the IFIT family by suppressing IFIT family genes expression or methylation of 5'' cap of viral molecules. In addition, the variants of IFIT family genes could significantly influence the outcome of hepatitis C virus (HCV) therapy. We believe that our current review provides a comprehensive picture for the community to understand the structure and function of IFIT family genes in response to pathogens in human, as well as in animals.     

Pulmonary embolism and 3-month outcomes in 4036 patients with venous thromboembolism and chronic obstructive pulmonary disease: data from the RIETE registry

Background

Patients with chronic obstructive pulmonary disease (COPD) have a modified clinical presentation of venous thromboembolism (VTE) but also a worse prognosis than non-COPD patients with VTE. As it may induce therapeutic modifications, we evaluated the influence of the initial VTE presentation on the 3-month outcomes in COPD patients.

Methods

COPD patients included in the on-going world-wide RIETE Registry were studied. The rate of pulmonary embolism (PE), major bleeding and death during the first 3 months in COPD patients were compared according to their initial clinical presentation (acute PE or deep vein thrombosis (DVT)).

Results

Of the 4036 COPD patients included, 2452 (61%; 95% CI: 59.2-62.3) initially presented with PE. PE as the first VTE recurrence occurred in 116 patients, major bleeding in 101 patients and mortality in 443 patients (Fatal PE: first cause of death). Multivariate analysis confirmed that presenting with PE was associated with higher risk of VTE recurrence as PE (OR, 2.04; 95% CI: 1.11-3.72) and higher risk of fatal PE (OR, 7.77; 95% CI: 2.92-15.7).

Conclusions

COPD patients presenting with PE have an increased risk for PE recurrences and fatal PE compared with those presenting with DVT alone. More efficient therapy is needed in this subtype of patients.     

Toward an integrative view of Optineurin functions

This review highlights recent advances in our understanding of the mechanisms of Optineurin (Optn) action and its implication in diseases. Optn has emerged as a key player regulating various physiological processes, including membrane trafficking, protein secretion, cell division and host defense against pathogens. Furthermore, there is growing evidence for an association of Optn mutations with human diseases such as primary open-angle glaucoma, amyotrophic lateral sclerosis and Paget’s disease of bone. Optn functions depend on its precise subcellular localization and its interaction with other proteins. Here, we review the mechanisms that allow Optn to ensure a timely and spatially coordinated integration of different physiological processes and discuss how their deregulation may lead to different pathologies.     

The primary cilium

The primary cilium is an antenna-like organelle that plays a vital role in organ generation and maintenance. It protrudes from the cell surface where it receives signals from the surrounding environment and relays them into the cell. These signals are then integrated to give the required outputs in terms of proliferation, differentiation, migration and polarization that ultimately lead to organ development and homeostasis. Defects in cilia function underlie a wide range of diverse but related human developmental or degenerative diseases. Collectively known as ciliopathies, these disorders present with varying severity and multiple organ involvement. The appreciation of the medical importance of the primary cilium has stimulated a huge effort into studies of the underlying cellular mechanisms. These in turn have revealed that ciliopathies result not only from defective assembly or organization of the primary cilium, but also from impaired ciliary signaling. This special edition of Organogenesis contains a set of review articles that highlight the role of the primary cilium in organ development and homeostasis, much of which has been learnt from studies of the associated human diseases. Here, we provide an introductory overview of our current understanding of the structure and function of the cilium, with a focus on the signaling pathways that are coordinated by primary cilia to ensure proper organ generation and maintenance.     

TRPM7 and its role in neurodegenerative diseases

Calcium (Ca²⁺) and magnesium (Mg²⁺) ions have been shown to play an important role in regulating various neuronal functions. In the present review we focus on the emerging role of transient potential melastatin-7 (TRPM7) channel in not only regulating Ca²⁺ and Mg²⁺ homeostasis necessary for biological functions, but also how alterations in TRPM7 function/expression could induce neurodegeneration. Although eight TRPM channels have been identified, the channel properties, mode of activation, and physiological responses of various TRPM channels are quite distinct. Among the known 8 TRPM channels only TRPM6 and TRPM7 channels are highly permeable to both Ca²⁺ and Mg²⁺; however here we will only focus on TRPM7 as unlike TRPM6, TRPM7 channels are abundantly expressed in neuronal cells. Importantly, the discrepancy in TRPM7 channel function and expression leads to various neuronal diseases such as Alzheimer disease (AD) and Parkinson disease (PD). Further, it is emerging as a key factor in anoxic neuronal death and in other neurodegenerative disorders. Thus, by understanding the precise involvement of the TRPM7 channels in different neurodegenerative diseases and by understanding the factors that regulate TRPM7 channels, we could uncover new strategies in the future that could evolve as new drug therapeutic targets for effective treatment of these neurodegenerative diseases.