Nickel induces intracellular calcium mobilization and pathophysiological responses in human cultured airway epithelial cells

Corrosion Products from Metallic Implants Induce ROS and Cell Death in Human Motoneurons In Vitro

Due to advances in surgical procedures and the biocompatibility of materials used in total joint replacement, more and younger patients are undergoing these procedures. Although state-of-the-art joint replacements can last 20 years or longer, wear and corrosion is still a major risk for implant failure, and patients with these implants are exposed for longer to these corrosive products. It is therefore important to investigate the potential effects on the whole organism. Released nanoparticles and ions derived from commonly used metal implants consist, among others, of cobalt, nickel, and chromium. The effect of these metallic products in the process of osteolysis and aseptic implant loosening has already been studied; however, the systemic effect on other cell types, including neurons, remains elusive. To this end, we used human iPSC-derived motoneurons to investigate the effects of metal ions on human neurons. We treated human motoneurons with ion concentrations regularly found in patients, stained them with MitoSOX and propidium iodide, and analyzed them with fluorescence-assisted cell sorting (FACS). We found that upon treatment human motoneurons suffered from the formation of ROS and subsequently died. These effects were most prominent in motoneurons treated with 500 μM of cobalt or nickel, in which we observed significant cell death, whereas chromium showed fewer ROS and no apparent impairment of motoneurons. Our results show that the wear and corrosive products of metal implants at concentrations readily available in peri-implant tissues induced ROS and subsequently cell death in an iPSC-derived motoneuron cell model. We therefore conclude that monitoring of neuronal impairment is important in patients undergoing total joint replacement.

The calcium-sensing receptor in inflammation: Recent updates

The Calcium-Sensing Receptor (CaSR) is a member of the class C of G-proteins coupled receptors (GPCRs), it plays a pivotal role in calcium homeostasis by directly controlling calcium excretion in the kidneys and indirectly by regulating parathyroid hormone (PTH) release from the parathyroid glands. The CaSR is found to be ubiquitously expressed in the body, playing a plethora of additional functions spanning from fluid secretion, insulin release, neuronal development, vessel tone to cell proliferation and apoptosis, to name but a few. The present review aims to elucidate and clarify the emerging regulatory effects that the CaSR plays in inflammation in several tissues, where it mostly promotes pro-inflammatory responses, with the exception of the large intestine, where contradictory roles have been recently reported. The CaSR has been found to be expressed even in immune cells, where it stimulates immune response and chemokinesis. On the other hand, CaSR expression seems to be boosted under inflammatory stimulus, in particular, by pro-inflammatory cytokines. Because of this, the CaSR has been addressed as a key factor responsible for hypocalcemia and low levels of PTH that are commonly found in critically ill patients under sepsis or after burn injury. Moreover, the CaSR has been found to be implicated in autoimmune-hypoparathyroidism, recently found also in patients treated with immune-checkpoint inhibitors. Given the tight bound between the CaSR, calcium and vitamin D metabolism, we also speculate about their roles in the pathogenesis of severe acute respiratory syndrome coronavirus-19 (SARS-COVID-19) infection and their impact on patients' prognosis. We will further explore the therapeutic potential of pharmacological targeting of the CaSR for the treatment and management of aberrant inflammatory responses.

Involvement of Ca2+ and ROS signals in nickel-impaired human sperm function

As one of the main environmental pollutants and occupational hazards, nickel has been reported to have mutagenic, carcinogenic, and teratogenic properties, as well as reproductive toxicity. However, how nickel affects human reproduction is still unclear. In this study, the toxicity of nickel on human sperm and the underlying mechanisms were evaluated in vitro. We found that NiCl₂ (10, 50, and 250 μM) impaired sperm total motility and progressive motility in a dose- and time-dependent manner. In addition, sperm hyperactivation and the ability of human sperm to penetrate a viscous medium were found to be compromised after nickel exposure. Mechanically, NiCl₂ significantly inhibited the basal intracellular Ca²⁺ signaling. Besides, reactive oxygen species (ROS), superoxide, and malondialdehyde levels were increased in human sperm after exposure to different concentrations of NiCl₂. Consistently, eliminating excess ROS by N-acetyl-L-cysteine or tocopherol significantly alleviated nickel-impaired sperm motility. Taken together, these results revealed that nickel could compromise sperm functions by interfering with Ca²⁺ signaling and inducing excessive oxidative stress. These findings suggest that, in the high and occupational nickel exposure environments, the contribution of nickel toxicity to the males who wish to preserve their fertility is worthy of careful evaluation.

NiONPs-induced alteration in calcium signaling and mitochondrial function in pulmonary artery endothelial cells involves oxidative stress and TRPV4 channels disruption

In New Caledonia, anthropic activities, such as mining, increase the natural erosion of soils in nickel mines, which in turn, releases nickel oxide nanoparticles (NiONPs) into the atmosphere. Pulmonary vascular endothelial cells represent one of the primary targets for inhaled nanoparticles. The objective of this in vitro study was to assess the cytotoxic effects of NiONPs on human pulmonary artery endothelial cells (HPAEC). Special attention will be given to the level of oxidative stress and calcium signaling, which are involved in the physiopathology of cardiovascular diseases. HPAEC were exposed to NiONPs (0.5-150 μg/cm²) for 4 or 24 h. The following different endpoints were studied: (i) ROS production using CM-H₂DCF-DA probe, electron spin resonance, and MitoSOX probe; the SOD activity was also measured (ii) calcium signaling with Fluo4-AM, Rhod-2, and Fluo4-FF probes; (iii) inflammation by IL-6 production and secretion and, (iv) mitochondrial dysfunction and apoptosis with TMRM and MitoTracker probes, and AnnexinV/PI. Our results have evidenced that NiONPs induced oxidative stress in HPAEC. This was demonstrated by an increase in ROS production and a decrease in SOD activity, the two mechanisms seem to trigger a pro-inflammatory response with IL-6 secretion. In addition, NiONPs exposure altered calcium homeostasis inducing an increased cytosolic calcium concentration ([Ca²⁺]_i) that was significantly reduced by the extracellular calcium chelator EGTA and the TRPV4 inhibitor HC-067047. Interestingly, exposure to NiONPs also altered TRPV4 activity. Finally, HPAEC exposure to NiONPs increased intracellular levels of both ROS and calcium ([Ca²⁺]_m) in mitochondria, leading to mitochondrial dysfunction and HPAEC apoptosis.

Kinetic mechanisms by which nickel alters the calcium (Ca2+) transport in intact rat liver

In the present work, the multiple-indicator dilution (MID) technique was used to investigate the kinetic mechanisms by which nickel (Ni2+) affects the calcium (Ca2+) transport in intact rat liver. 45Ca2+ and extra- and intracellular space indicators were injected in livers perfused with 1 mM Ni2+, and the outflow profiles were analyzed by a mathematical model. For comparative purposes, the effects of norepinephrine were measured. The influence of Ni2+ on the cytosolic Ca2+ concentration ([Ca2+]c) in human hepatoma Huh7 cells and on liver glycogen catabolism, a biological response sensitive to cellular Ca2+, was also evaluated. The estimated transfer coefficients of 45Ca2+ transport indicated two mechanisms by which Ni2+ increases the [Ca2+]c in liver under steady-state conditions: (1) an increase in the net efflux of Ca2+ from intracellular Ca2+ stores due to a stimulus of Ca2+ efflux to the cytosolic space along with a diminution of Ca2+ re-entry into the cellular Ca2+ stores; (2) a decrease in Ca2+ efflux from the cytosolic space to vascular space, minimizing Ca2+ loss. Glycogen catabolism activated by Ni2+ was transient contrasting with the sustained activation induced by norepinephrine. Ni2+ caused a partial reduction in the norepinephrine-induced stimulation in the [Ca2+]c in Huh7 cells. Our data revealed that the kinetic parameters of Ca2+ transport modified by Ni2+ in intact liver are similar to those modified by norepinephrine in its first minutes of action, but the membrane receptors or Ca2+ transporters affected by Ni2+ seem to be distinct from those known to be modulated by norepinephrine.

Repurposing calcium-sensing receptor agonist cinacalcet for treatment of CFTR-mediated secretory diarrheas

Diarrhea is a major cause of global mortality, and outbreaks of secretory diarrhea such as cholera remain an important problem in the developing world. Current treatment of secretory diarrhea primarily involves supportive measures, such as fluid replacement. The calcium-sensing receptor (CaSR) regulates multiple biological activities in response to changes in extracellular Ca²⁺. The FDA-approved drug cinacalcet is an allosteric activator of CaSR used for treatment of hyperparathyroidism. Here, we found by short-circuit current measurements in human colonic T84 cells that CaSR activation by cinacalcet reduced forskolin-induced Cl^– secretion by greater than 80%. Cinacalcet also reduced Cl^– secretion induced by cholera toxin, heat-stable E. coli enterotoxin, and vasoactive intestinal peptide (VIP). The cinacalcet effect primarily involved indirect inhibition of cystic fibrosis transmembrane conductance regulator–mediated (CFTR-mediated) Cl^– secretion following activation of CaSR and downstream phospholipase C and phosphodiesterases. In mice, cinacalcet reduced fluid accumulation by more than 60% in intestinal closed loop models of cholera and traveler’s diarrhea. The cinacalcet effect involved both inhibition of CFTR-mediated secretion and stimulation of sodium-hydrogen exchanger 3–mediated absorption. These findings support the therapeutic utility of the safe and commonly used drug cinacalcet in CFTR-dependent secretory diarrheas, including cholera, traveler’s diarrhea, and VIPoma.

Ni and TiO2 nanoparticles cause adhesion and cytoskeletal changes in human osteoblasts

Titanium-based alloys have established a crucial role in implantology. As material deteriorates overtime, nanoparticles of TiO₂ and Ni are released. This study is focused on the impact of TiO₂ and Ni nanoparticles with size of 100 nm on cytoskeletal and adhesive changes in human physiological and osteoarthritic osteoblasts. The impact of nanoparticles with concentration of 1.5 ng/mL on actin and tubulin expression and gene expression of FAK and ICAM-1 was studied. The cell size and actin expression of physiological osteoblasts decreased in presence of Ni nanoparticles, while TiO₂ nanoparticles caused increase in cell size and actin expression. Both cell lines expressed more FAK as a response to TiO₂ nanoparticles. ICAM-1 gene was overexpressed in both cell lines as a reaction to both types of nanoparticles. The presented study shows a crucial role of Ni and TiO₂ nanoparticles in human osteoblast cytoskeletal and adhesive changes, especially connected with the osteoarthritic cells. Graphical abstract.

A Ciliary Motility Index for Activity Measurement in Cell Cultures With Respiratory Syncytial Virus

BACKGROUND

The respiratory epithelium is frequently infected by the respiratory syncytial virus, resulting in inflammation, a reduction in cilia activity and an increase in the production of mucus.

METHODS

In this study, an automatic method has been proposed to characterize the ciliary motility from cell cultures by means of a motility index using a dense optical flow algorithm. This method allows us to determine the ciliary beat frequency (CBF) together with a ciliary motility index of the cells in the cultures. The object of this analysis is to automatically distinguish between normal and infected cells in a culture.

RESULTS

The method was applied in 2 stages. It was concluded from the first stage that the CBF is not a good enough indicator to discriminate between the control and infected cultures. However, the ciliary motility index does succeed in discriminating between the control and infected cultures using the t test with a value t = 6.46 and P < .001. In the second stage, it has been shown that the ciliary motility index did not differ significantly between patients, and the analysis of variance test gives α = 0.05, F = 1.61, P = .20. A threshold for this index has been determined using a receiver operating characteristics analysis that gives an area under the curve of 0.93.

CONCLUSIONS

We have obtained a ciliary motility index that is able to discriminate between control and infected cultures after the eighth postinfection day. After infection, there is a rapid cilia loss of the cells and the measured CBF corresponds to the remaining noninfected cells. This is why the CBF does not discriminate between the control and the infected cells.

Calcium-dependent cyto- and genotoxicity of nickel metal and nickel oxide nanoparticles in human lung cells

Background

Genotoxicity is an important toxicological endpoint due to the link to diseases such as cancer. Therefore, an increased understanding regarding genotoxicity and underlying mechanisms is needed for assessing the risk with exposure to nanoparticles (NPs). The aim of this study was to perform an in-depth investigation regarding the genotoxicity of well-characterized Ni and NiO NPs in human bronchial epithelial BEAS-2B cells and to discern possible mechanisms. Comparisons were made with NiCl₂ in order to elucidate effects of ionic Ni.

Methods

BEAS-2B cells were exposed to Ni and NiO NPs, as well as NiCl₂, and uptake and cellular dose were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS). The NPs were characterized in terms of surface composition (X-ray photoelectron spectroscopy), agglomeration (photon cross correlation spectroscopy) and nickel release in cell medium (ICP-MS). Cell death (necrosis/apoptosis) was investigated by Annexin V-FITC/PI staining and genotoxicity by cytokinesis-block micronucleus (cytome) assay (OECD 487), chromosomal aberration (OECD 473) and comet assay. The involvement of intracellular reactive oxygen species (ROS) and calcium was explored using the fluorescent probes, DCFH-DA and Fluo-4.

Results

NPs were efficiently taken up by the BEAS-2B cells. In contrast, no or minor uptake was observed for ionic Ni from NiCl₂. Despite differences in uptake, all exposures (NiO, Ni NPs and NiCl₂) caused chromosomal damage. Furthermore, NiO NPs were most potent in causing DNA strand breaks and generating intracellular ROS. An increase in intracellular calcium was observed and modulation of intracellular calcium by using inhibitors and chelators clearly prevented the chromosomal damage. Chelation of iron also protected against induced damage, particularly for NiO and NiCl₂.

Conclusions

This study has revealed chromosomal damage by Ni and NiO NPs as well as Ni ionic species and provides novel evidence for a calcium-dependent mechanism of cyto- and genotoxicity.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0268-y) contains supplementary material, which is available to authorized users.

JAK2 mediates lung fibrosis, pulmonary vascular remodelling and hypertension in idiopathic pulmonary fibrosis: an experimental study

BACKGROUND

Pulmonary hypertension (PH) is a common disorder in patients with idiopathic pulmonary fibrosis (IPF) and portends a poor prognosis. Recent studies using vasodilators approved for PH have failed in improving IPF mainly due to ventilation (V)/perfusion (Q) mismatching and oxygen desaturation. Janus kinase type 2 (JAK2) is a non-receptor tyrosine kinase activated by a broad spectrum of profibrotic and vasoactive mediators, but its role in PH associated to PH is unknown.

OBJECTIVE

The study of JAK2 as potential target to treat PH in IPF.

METHODS AND RESULTS

JAK2 expression was increased in pulmonary arteries (PAs) from IPF (n=10; 1.93-fold; P=0.0011) and IPF+PH (n=9; 2.65-fold; P<0.0001) compared with PA from control subjects (n=10). PA remodelling was evaluated in human pulmonary artery endothelial cells (HPAECs) and human pulmonary artery smooth muscle cells (HPASMCs) from patients with IPF in vitro treated with the JAK2 inhibitor JSI-124 or siRNA-JAK2 and stimulated with transforming growth factor beta. Both JSI-124 and siRNA-JAK2 inhibited the HPAEC to mesenchymal transition and the HPASMCs to myofibroblast transition and proliferation. JAK2 inhibition induced small PA relaxation in precision-cut lung slice experiments. PA relaxation was dependent of the large conductance calcium-activated potassium channel (BK_Ca). JAK2 inhibition activated BK_Ca channels and reduced intracellular Ca²⁺. JSI-124 1 mg/kg/day, reduced bleomycin-induced lung fibrosis, PA remodelling, right ventricular hypertrophy, PA hypertension and V/Q mismatching in rats. The animal studies followed the ARRIVE guidelines.

CONCLUSIONS

JAK2 participates in PA remodelling and tension and may be an attractive target to treat IPF associated to PH.

The JAK2 pathway is activated in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is the most rapidly progressive and fatal fibrotic disorder, with no curative therapies. The signal transducer and activator of transcription 3 (STAT3) protein is activated in lung fibroblasts and alveolar type II cells (ATII), thereby contributing to lung fibrosis in IPF. Although activation of Janus kinase 2 (JAK2) has been implicated in proliferative disorders, its role in IPF is unknown. The aim of this study was to analyze JAK2 activation in IPF, and to determine whether JAK2/STAT3 inhibition is a potential therapeutic strategy for this disease.

Methods and results

JAK2/p-JAK2 and STAT3/pSTAT3 expression was evaluated using quantitative real time-PCR, western blotting, and immunohistochemistry. Compared to human healthy lung tissue (n = 10) both proteins were upregulated in the lung tissue of IPF patients (n = 12). Stimulating primary ATII and lung fibroblasts with transforming growth factor beta 1 or interleukin (IL)-6/IL-13 activated JAK2 and STAT3, inducing epithelial to mesenchymal and fibroblast to myofibroblast transitions. Dual p-JAK2/p-STAT3 inhibition with JSI-124 or silencing of JAK2 and STAT3 genes suppressed ATII and the fibroblast to myofibroblast transition, with greater effects than the sum of those obtained using JAK2 or STAT3 inhibitors individually. Dual rather than single inhibition was also more effective for inhibiting fibroblast migration, preventing increases in fibroblast senescence and Bcl-2 expression, and ameliorating impaired autophagy. In rats administered JSI-124, a dual inhibitor of p-JAK2/p-STAT3, at a dose of 1 mg/kg/day, bleomycin-induced lung fibrosis was reduced and collagen deposition in the lung was inhibited, as were JAK2 and STAT3 activation and several markers of fibrosis, autophagy, senescence, and anti-apoptosis.

Conclusions

JAK2 and STAT3 are activated in IPF, and their dual inhibition may be an attractive strategy for treating this disease.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0728-9) contains supplementary material, which is available to authorized users.

Nickel chloride (NiCl2) in hepatic toxicity: apoptosis, G2/M cell cycle arrest and inflammatory response

Up to now, the precise mechanism of Ni toxicology is still indistinct. Our aim was to test the apoptosis, cell cycle arrest and inflammatory response mechanism induced by NiCl₂ in the liver of broiler chickens. NiCl₂ significantly increased hepatic apoptosis. NiCl₂ activated mitochondria-mediated apoptotic pathway by decreasing Bcl-2, Bcl-xL, Mcl-1, and increasing Bax, Bak, caspase-3, caspase-9 and PARP mRNA expression. In the Fas-mediated apoptotic pathway, mRNA expression levels of Fas, FasL, caspase-8 were increased. Also, NiCl₂ induced ER stress apoptotic pathway by increasing GRP78 and GRP94 mRNA expressions. The ER stress was activated through PERK, IRE1 and ATF6 pathways, which were characterized by increasing eIF2α, ATF4, IRE1, XBP1 and ATF6 mRNA expressions. And, NiCl₂ arrested G₂/M phase cell cycle by increasing p53, p21 and decreasing cdc2, cyclin B mRNA expressions. Simultaneously, NiCl₂ increased TNF-α, IL-1β, IL-6, IL-8 mRNA expressions through NF-κB activation. In conclusion, NiCl₂ induces apoptosis through mitochondria, Fas and ER stress-mediated apoptotic pathways and causes cell cycle G₂/M phase arrest via p53-dependent pathway and generates inflammatory response by activating NF-κB pathway.

Prevalence of exposure of heavy metals and their impact on health consequences

Even in the current era of growing technology, the concentration of heavy metals present in drinking water is still not within the recommended limits as set by the regulatory authorities in different countries of the world. Drinking water contaminated with heavy metals namely; arsenic, cadmium, nickel, mercury, chromium, zinc, and lead is becoming a major health concern for public and health care professionals. Occupational exposure to heavy metals is known to occur by the utilization of these metals in various industrial processes and/or contents including color pigments and alloys. However, the predominant source resulting in measurable human exposure to heavy metals is the consumption of contaminated drinking water and the resulting health issues may include cardiovascular disorders, neuronal damage, renal injuries, and risk of cancer and diabetes. The general mechanism involved in heavy metal-induced toxicity is recognized to be the production of reactive oxygen species resulting oxidative damage and health related adverse effects. Thus utilization of heavy metal-contaminated water is resulting in high morbidity and mortality rates all over the world. Thereby, feeling the need to raise the concerns about contribution of different heavy metals in various health related issues, this article has discussed the global contamination of drinking water with heavy metals to assess the health hazards associated with consumption of heavy metal-contaminated water. A relationship between exposure limits and ultimate responses produced as well as the major organs affected have been reviewed. Acute and chronic poisoning symptoms and mechanisms responsible for such toxicities have also been discussed.

Emerging concepts in smooth muscle contributions to airway structure and function: implications for health and disease

Airway structure and function are key aspects of normal lung development, growth, and aging, as well as of lung responses to the environment and the pathophysiology of important diseases such as asthma, chronic obstructive pulmonary disease, and fibrosis. In this regard, the contributions of airway smooth muscle (ASM) are both functional, in the context of airway contractility and relaxation, as well as synthetic, involving production and modulation of extracellular components, modulation of the local immune environment, cellular contribution to airway structure, and, finally, interactions with other airway cell types such as epithelium, fibroblasts, and nerves. These ASM contributions are now found to be critical in airway hyperresponsiveness and remodeling that occur in lung diseases. This review emphasizes established and recent discoveries that underline the central role of ASM and sets the stage for future research toward understanding how ASM plays a central role by being both upstream and downstream in the many interactive processes that determine airway structure and function in health and disease.

ISG15 Is Upregulated in Respiratory Syncytial Virus Infection and Reduces Virus Growth through Protein ISGylation

Human respiratory syncytial virus (RSV), for which neither a vaccine nor an effective therapeutic treatment is currently available, is the leading cause of severe lower respiratory tract infections in children. Interferon-stimulated gene 15 (ISG15) is a ubiquitin-like protein that is highly increased during viral infections and has been reported to have an antiviral or a proviral activity, depending on the virus. Previous studies from our laboratory demonstrated strong ISG15 upregulation during RSV infection in vitro. In this study, an in-depth analysis of the role of ISG15 in RSV infection is presented. ISG15 overexpression and small interfering RNA (siRNA)-silencing experiments, along with ISG15 knockout (ISG15(-/-)) cells, revealed an anti-RSV effect of the molecule. Conjugation inhibition assays demonstrated that ISG15 exerts its antiviral activity via protein ISGylation. This antiviral activity requires high levels of ISG15 to be present in the cells before RSV infection. Finally, ISG15 is also upregulated in human respiratory pseudostratified epithelia and in nasopharyngeal washes from infants infected with RSV, pointing to a possible antiviral role of the molecule in vivo. These results advance our understanding of the innate immune response elicited by RSV and open new possibilities to control infections by the virus.

IMPORTANCE

At present, no vaccine or effective treatment for human respiratory syncytial virus (RSV) is available. This study shows that interferon-stimulated gene 15 (ISG15) lowers RSV growth through protein ISGylation. In addition, ISG15 accumulation highly correlates with the RSV load in nasopharyngeal washes from children, indicating that ISG15 may also have an antiviral role in vivo. These results improve our understanding of the innate immune response to RSV and identify ISG15 as a potential target for virus control.

Goldfish brain and heart are well protected from Ni²⁺-induced oxidative stress

After 96 h goldfish exposure to 10, 25 or 50 mg/L of Ni(2+) no Ni accumulation was found in the brain, but lipid peroxide concentration was by 44% elevated in the brain, whereas carbonyl protein content was by 45-45% decreased in the heart. High molecular mass thiol concentration was enhanced by 30% in the heart, while in the brain low molecular mass thiol concentration increased by 28-88%. Superoxide dismutase activity was by 27% and 35% increased in the brain and heart, respectively. Glutathione peroxidase activity was lowered to 38% and 62% of control values in both tissues, whereas catalase activity was increased in the heart by 15-45%, accompanied by 18-29% decreased glutathione reductase activity. The disturbances of free radical processes in the brain and heart might result from Ni-induced injuries to other organs with more prominent changes in the heart, because of close contact of this organ with blood, whereas the blood-brain barrier seems to protect the brain.

Different mechanism of LPS-induced calcium increase in human lung epithelial cell and microvascular endothelial cell: a cell culture study in a model for ARDS

Acute respiratory distress syndrome (ARDS) is a contemporary term incorporating the historic 'acute lung injury' and the colloquial term 'shock lung'. ARDS remains a serious and enigmatic human disease, causing significant mortality. The mechanisms involved at the alveolar cell/capillary endothelial interface have been explored but to date we lack clarity on the role of intracellular calcium ([Ca(2+)]i) fluxes across this interface. To explore the mechanisms of Ca(2+) induced inflammatory reaction in epithelial cells and pulmonary microvascular endothelial cells (HMVEC) located at the two sides of blood-air barrier, lung epithelial A549 and HMVEC cells were treated with LPS. Our results demonstrated that LPS evoked the increase of [Ca(2+)]i, TNF-α and IL-8 in both cells types. The [Ca(2+)]i increases involved intracellular but not extracellular Ca(2+) sources in A549, but both intracellular and extracellular Ca(2+) sources in HMVEC cells. The effects of LPS on both cells types were completely inhibited by the combination of LPS and CaSR-targeted siRNA. Furthermore, LPS-inhibited cell proliferations were significantly reversed by the combined treatment. Therefore, LPS induced different mechanisms of [Ca(2+)]i increase during the activation of CaSR in A549 and HMVEC cells, which translates into functional outputs related to ARDS.

New adenylate kinase 7 (AK7) mutation in primary ciliary dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a congenital hereditary disease affecting 1/20,000-60,000 people that causes chronic sinusitis, bronchiectasis, sinus hypoplasia, secretory otitis media, and low fertility. The complexity and heterogeneity of the disease make diagnosis difficult. Although the genetic origin of PCD is clear, mutations in only five genes have been associated with the disease, and, to date, no disease-causing gene has been identified. Recently, low levels of AK7 gene expression have been linked to PCD. This study was designed to determine the mutational status of the AK7 gene in 31 PCD (17 PCD and 14 Kartagener syndrome diagnosed) patients compared with 40 healthy volunteers. We also determined the AK7 sequence in two families with members with PCD and investigated ciliary activity and ciliogenesis in one patient with a mutation in AK7.

METHODS

We analyzed nasal mucociliary transport and cilial ultrastructure by electron microscopy and studied nasal ciliary beat frequency and beat pattern using high-resolution digital high speed video (DHSV) imaging. Mutation analyses were performed by direct resequencing of the 18 exons of the AK7 gene. Air-liquid interface differentiated cultures were studied using DHSV imaging and histochemistry. AK7 gene expression was studied by real-time reverse-transcription polymerase chain reaction.

RESULTS

We identified two mutations in the AK7 gene, the described single nucleotide polymorphism (rs2369679), and a new mutation (c.1214insT) that, to the best of our knowledge, has not been described previously. Family and functional studies indicated that c.1214insT could be related to PCD.

CONCLUSION

Our results indicate that AK7 may be involved in the development of PCD.

Respiratory syncytial virus inhibits ciliagenesis in differentiated normal human bronchial epithelial cells: effectiveness of N-acetylcysteine

Persistent respiratory syncytial virus (RSV) infections have been associated with the exacerbation of chronic inflammatory diseases, including chronic obstructive pulmonary disease (COPD). This virus infects the respiratory epithelium, leading to chronic inflammation, and induces the release of mucins and the loss of cilia activity, two factors that determine mucus clearance and the increase in sputum volume. These alterations involve reactive oxygen species-dependent mechanisms. The antioxidant N-acetylcysteine (NAC) has proven useful in the management of COPD, reducing symptoms, exacerbations, and accelerated lung function decline. NAC inhibits RSV infection and mucin release in human A549 cells. The main objective of this study was to analyze the effects of NAC in modulating ciliary activity, ciliagenesis, and metaplasia in primary normal human bronchial epithelial cell (NHBEC) cultures infected with RSV. Our results indicated that RSV induced ultrastructural abnormalities in axonemal basal bodies and decreased the expression of β-tubulin as well as two genes involved in ciliagenesis, FOXJ1 and DNAI2. These alterations led to a decrease in ciliary activity. Furthermore, RSV induced metaplastic changes to the epithelium and increased the number of goblet cells and the expression of MUC5AC and GOB5. NAC restored the normal functions of the epithelium, inhibiting ICAM1 expression, subsequent RSV infection through mechanisms involving nuclear receptor factor 2, and the expression of heme oxygenase 1, which correlated with the restoration of the antioxidant capacity, the intracellular H(2)O(2) levels and glutathione content of NHBECs. The results presented in this study support the therapeutic use of NAC for the management of chronic respiratory diseases, including COPD.

Length-dependent pathogenic effects of nickel nanowires in the lungs and the peritoneal cavity

The use of fibre-shaped nanomaterials in commercial applications has met with concern that they could cause health effects similar to those seen with pathogenic fibres such as certain forms of asbestos. Of the attributes which form the fibre pathogenicity paradigm, fibre length is thought to be a critical factor in determining fibre toxicity. We have previously shown that carbon nanotubes display such length-dependent pathogenicity but it remains unclear if other forms of fibrous nanomaterials conform to the fibre pathogenicity paradigm. As such, our aim is to determine the generality of this hypothesis by asking whether a radically different form of fibrous nanomaterial, nickel nanowires, show length-dependent pathogenicity. Our results indicate that nickel nanowires synthesised to be predominantly long (>20 μm) show the ability to elicit strong inflammation in the mouse peritoneal model in a dose-dependent manner; inflammation or fibrosis was not seen with the short (<5 μm) nanowires. This length-dependent response was also seen after lung aspiration and within a macrophage in vitro model adding further weight to the contention that fibre length is an important driver of hazard potential. This may have important implications when considering the hazard posed by fibrous nanomaterials and their regulation in workplaces.

Pharmacological evidences for the stimulation of calcium-sensing receptors by nifedipine in gingival fibroblasts

OBJECTIVE

To investigate pharmacologically whether CaSRs are involved in the Ca(2+) antagonist-induced [Ca(2+)]i elevation in gingival fibroblasts.

MATERIALS AND METHODS

Gin-1 cells, normal human gingival fibroblasts, were used as the material. The [Ca(2+)] i was measured with fura-2/AM, a Ca(2+)-sensitive fluorescent dye.

RESULTS

At first, we confirmed the existence of CaSRs in these cells by showing that [Ca(2+)] i was elevated by high concentrations of extracellular Ca(2+) and by prototypic agonists of the CaSR such as gentamicin. The action of gentamicin was antagonized by inhibitors of phospholipase C (PLC), inositol trisphosphate (IP(3)) receptors, NSCCs, and, importantly, by the CaSR antagonist, NPS2390. Furthermore, the action of gentamicin was potentiated by activators of PLC and protein kinase C (PKC). This confirmed the pathway components mediating Ca(2+) responses to a known agonist of the CaSR. We then investigated whether nifedipine (an L-type Ca(2+) channel blocker) stimulates CaSRs to elevate [Ca(2+)] i via a similar mechanism. Nifedipine Ca(2+) responses were dose-dependently blocked by NPS2390 and by the same inhibitors of PLC, IP(3) receptors, and NSCCs that disrupted the action of gentamicin. Calphostin C (a PKC inhibitor) and TMB-8 (an inhibitor of Ca(2+) release from stores) also inhibited the nifedipine-induced [Ca(2+)] i elevation.

CONCLUSION

These findings suggest that CaSRs are involved in the nifedipine-induced [Ca(2+)] i elevation in gingival fibroblasts.

Exploring the molecular mechanisms of nickel-induced genotoxicity and carcinogenicity: a literature review

Nickel, a naturally occurring element that exists in various mineral forms, is mainly found in soil and sediment, and its mobilization is influenced by the physicochemical properties of the soil. Industrial sources of nickel include metallurgical processes such as electroplating, alloy production, stainless steel, and nickel-cadmium batteries. Nickel industries, oil- and coal-burning power plants, and trash incinerators have been implicated in its release into the environment. In humans, nickel toxicity is influenced by the route of exposure, dose, and solubility of the nickel compound. Lung inhalation is the major route of exposure for nickel-induced toxicity. Nickel can also be ingested or absorbed through the skin. The primary target organs are the kidneys and lungs. Other organs such as the liver, spleen, heart, and testes can also be affected to a lesser extent. Although the most common health effect is an allergic reaction, research has also demonstrated that nickel is carcinogenic to humans. The focus of the present review is on recent research concerning the molecular mechanisms of nickel-induced genotoxicity and carcinogenicity. We first present a background on the occurrence of nickel in the environment, human exposure, and human health effects.

Cigarette smoke exposure up-regulates endothelin receptor B in human pulmonary artery endothelial cells: molecular and functional consequences

BACKGROUND AND PURPOSE

Pulmonary arteries from smokers and chronic obstructive pulmonary disease patients show abnormal endothelium-dependent vascular reactivity. We studied the effect of cigarette smoke extract (CSE) on endothelin receptor B (ET(B) ) expression in human pulmonary artery endothelial cells (HPAECs) and its role in endothelial dysfunction.

EXPERIMENTAL APPROACH

ET(B) receptor expression was measured by real time RT-PCR, Western blot and immunofluorescence. Cell contraction, intracellular Ca(2+) , F/G-actin, RhoA activity, myosin light chain phosphorylation, ET, NO, thromboxane (Tx)A(2) and reactive oxygen species (ROS) were measured by traction microscopy, fluorescence microscopy, phalloidin fluorescence, colorimetric assay, Western blot, elisa and DCFDA fluorescence respectively.

KEY RESULTS

Cigarette smoke extract dose-dependently increased ET(B) receptor expression in HPAECs after 24h incubation. CSE-induced ET(B) expression was attenuated by bosentan, the ET(B) receptor antagonist BQ788, the Rho kinase antagonist Y27632 and the antioxidant N-acetylcysteine. A monoclonal antibody to ET-1 prevented CSE-induced ET(B) receptor overexpression. Twenty-four hour exposure to ET-1 dose-dependently increased ET(B) receptor expression, mimicking the effect of CSE. CSE-induced ET(B) receptor overexpression caused greater cell contraction; increased intracellular Ca(2+) ; increased F/G-actin and RhoA activity; increased myosin light chain phosphorylation; augmented TxA(2) and ROS production; and decreased NO after acute ET-1 (10nM). These effects were attenuated by bosentan, BQ788, Y27632 and N-acetylcysteine.

CONCLUSIONS AND IMPLICATION

Cigarette smoke extract induced ET(B) receptor overexpression by a feed forward mechanism mediated partly by ET release, promoting HPAEC dysfunction and attenuated by ET(B) receptor blockade, Rho kinase and ROS inhibition. These results provide support for the use of bosentan in CS-related endothelial dysfunction.

Influence of Transmural Pressure and Cytoskeletal Structure on NF-κB Activation in Respiratory Epithelial Cells

Respiratory epithelial cells are exposed to complex mechanical forces which are often modulated during pathological conditions such as Otitis Media and acute lung injury. The transduction of these mechanical forces into altered inflammatory signaling may play an important role in the persistence of disease conditions and inflammation. In this study, we investigated how static and oscillatory pressures altered the activation of NF-κB inflammatory pathways and how changes in the actin cytoskeleton influenced the mechanotransduction of pressure into NF-κB activation. An in vitro system was used to apply static and oscillatory pressures to alveolar epithelial cells cultured at an air-liquid interface. Latrunculin A and Jasplakinolide were used to alter the cytoskeleton and tight-junction structure and ELISA was used to monitor activation of NF-κB. Results indicate that both static and oscillatory pressures can activate NF-κB and that this activation is magnitude-dependent at low oscillation frequencies only. Jasplakinolide treated cells did not exhibit significant changes in normalized NF-κB activation compared to unloaded controls while Latrunculin treated cells exhibited increases in normalized NF-κB activation only at low frequency or static pressures. These results indicate that altering the actin cytoskeleton may be a useful way to mitigate the mechanotransduction of pressure forces into inflammatory signaling.