Mitochondria, responding to a wide variety of signals, including oxidative stress, are critical in regulating apoptosis that plays a key role in the pathogenesis of a variety of cardiovascular diseases. A number of mitochondrial proteins and pathways have been found to be involved in the mitochondrial dependent apoptosis mechanism, such as optic atrophy 1 (OPA1), sirtuin 3 (Sirt3), deacetylase enzyme and cAMP signal. In the present work we report a network among OPA1, Sirt3 and cAMP in ROS-dependent apoptosis. Rat myoblastic H9c2 cell lines, were treated with tert-butyl hydroperoxide (t-BHP) to induce oxidative stress-dependent apoptosis. FRET analysis revealed a selective decrease of mitochondrial cAMP in response to t-BHP treatment. This was associated with a decrease of Sirt3 protein level and proteolytic processing of OPA1. Pretreatment of cells with permeant analogous of cAMP (8-Br-cAMP) protected the cell from apoptosis preventing all these events. Using H89, inhibitor of the protein kinase A (PKA), and protease inhibitors, evidences have been obtained that ROS-dependent apoptosis is associated with an alteration of mitochondrial cAMP/PKA signal that causes degradation/proteolysis of Sirt3 that, in turn, promotes acetylation and proteolytic processing of OPA1.

The role of colony stimulating factors (CSFs) in cystic fibrosis (CF) circulating neutrophils has not been thoroughly evaluated, considering that the neutrophil burden of lung inflammation in these subjects is very high. The aim of this study was to assess granulocyte-CSF (G-CSF) and granulocyte-macrophage-CSF (GM-CSF) levels in CF patients in various clinical conditions and how these cytokines impact on activation and priming of neutrophils. G-CSF and GM-CSF levels were measured in sputum and serum samples of stable CF patients (n = 21) and in CF patients with acute exacerbation before and after a course of antibiotic therapy (n = 19). CSFs were tested on non CF neutrophils to investigate their effects on reactive oxygen species (ROS) production, degranulation (CD66b, elastase, lactoferrin, MMP-9), and chemotaxis. At very low concentrations found in CF patients (0.005–0.1 ng/ml), both cytokines inhibited ROS production, while higher concentrations (1–5 ng/ml) exerted a stimulatory effect. While either CSF induced elastase and MMP-9 secretion, lactoferrin levels were increased only by G-CSF. Chemotaxis was inhibited by GM-CSF, but was increased by G-CSF. However, when present together at low concentrations, CSFs increased basal and fMLP-stimulated ROS production and chemotaxis. These results suggest the CSF levels that circulating neutrophils face before extravasating into the lungs of CF patients may enhance their function contributing to the airway damage.

No abstract

In patients with non-G551D mutations, ivacaftor improved both chloride transport in sweat ducts and chloride efflux in MNC, that is, functions directly imputed to CFTR.

2-Arachidonoylglicerol (2-AG) is an endocannabinoid that mimics the pharmacological effects of Δ⁹ tetrahydrocannabinol, the psychoactive component of the plant Cannabis sativa. It is present in many mammalian tissues, such as brain, liver, spleen, heart and kidney, where it exerts different biological effects either receptor mediated or independently of receptor activation. This work analyzes the effects of 2-AG on liver mitochondrial functions. It is shown that 2-AG causes a relevant decrease of calcium induced cyclosporine A sensitive cytochrome c release from mitochondria, a process representing an early event of the apoptotic program. Cyclosporin sensitive matrix swelling and ROS production measured under the same conditions are, on the contrary, almost unaffected or even enhanced, respectively, by 2-AG. Furthemore, 2-AG is found to stimulate resting state succinate oxidase activity and to inhibit oligomycin sensitive F₀F₁ ATP synthase activity. All these effects are apparently associated with 2-AG dependent alteration in the fluidity of the mitochondrial membranes, which was measured as generalized polarization of laurdan fluorescence.

The aim of this study was to understand whether insulin-like growth factor-binding protein-6 (IGFBP-6) has functional effects on neutrophils, in particular when they cross epithelium during inflammation. We found that IGFBP-6 increased ROS production (cytofluorimetry), degranulation of primary and tertiary granules (ELISA) and transmigration through the epithelial monolayer. No priming by IGFBP-6 on neutrophils stimulated by either PMA or fMLP was observed. IGFBP-6 is an agonist of neutrophils' functions, most likely when these cells have been already activated by other stimuli.

Cystic fibrosis (CF) is a genetic syndrome caused by mutations in the CF Transmembrane Conductance Regulator (CFTR) gene. In CF patients, chief morbidity and mortality are due to pulmonary manifestations. CFTR lack/dysfunction brings an altered ion flux through the airway epithelium and ablation of mucociliary clearance, which in turn ensues in colonization and infection by opportunistic bacterial pathogens and subsequent neutrophil-dominated inflammation. This response eventually leads to the damage of the lung tissue. A host of inflammatory mediators attract, activate, and reprogramme neutrophils to survive (avoiding apoptosis) and produce a wealth of proteases and radical oxygen species. The protease/antiprotease imbalance and oxidative stress have multiple downstream effects, including impaired mucus clearance, increased and self-perpetuating inflammation, and impaired immune responses, thus facilitating and fostering bacterial infections. On the other hand, CFTR lack or dysfunction is likely responsible for alterations in neutrophils concerning chemotaxis, phagocytosis, oxidative burst, degranulation, and neutrophil extracellular trap (NET) formation. A good opportunity to reveal new and non-invasive biomarkers of CF lung disease is the evaluation of circulating neutrophils. Indeed, neutrophil responses are now investigated as outcomes of the aetiological therapies in CF, such as hypertonic saline, antiproteases, CFTR correctors and potentiators.