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Summary The role of YODA MITOGEN ACTIVATED PROTEIN KINASE KINASE KINASE 4 (MAPKKK4) upstream of MITOGEN ACTIVATED PROTEIN KINASE 6 (MPK6) was studied during post-embryonic root development of Arabidopsis thaliana. Loss- and gain-of-function mutants of YODA (yda1 and ΔNyda1) were characterized in terms of root patterning, endogenous auxin content and global proteomes.We surveyed morphological and cellular phenotypes of yda1 and ΔNyda1 mutants suggesting possible involvement of auxin. Endogenous indole-3-acetic acid (IAA) levels were up-regulated in both mutants. Proteomic analysis revealed up-regulation of auxin biosynthetic enzymes tryptophan synthase and nitrilases in these mutants. The expression, abundance and phosphorylation of MPK3, MPK6 and MICROTUBULE ASSOCIATED PROTEIN 65–1 (MAP65-1) were characterized by quantitative polymerase chain reaction (PCR) and western blot analyses and interactions between MAP65-1, microtubules and MPK6 were resolved by quantitative co-localization studies and co-immunoprecipitations.yda1 and ΔNyda1 mutants showed disoriented cell divisions in primary and lateral roots, abortive cytokinesis, and differential subcellular localization of MPK6 and MAP65-1. They also showed deregulated expression of TANGLED1 (TAN1), PHRAGMOPLAST ORIENTING KINESIN 1 (POK1), and GAMMA TUBULIN COMPLEX PROTEIN 4 (GCP4).The findings that MPK6 localized to preprophase bands (PPBs) and phragmoplasts while the mpk6-4 mutant transformed with MPK6AEF (alanine (A)–glutamic acid (E)–phenylanine (F)) showed a root phenotype similar to that of yda1 demonstrated that MPK6 is an important player downstream of YODA. These data indicate that YODA and MPK6 are involved in post-embryonic root development through an auxin-dependent mechanism regulating cell division and mitotic microtubule (PPB and phragmoplast) organization.

Acute lung injury (ALI) represents a serious heterogenous pulmonary disorder with high mortality. Despite improved understanding of the pathophysiology, the efficacy of standard therapies such as lung-protective mechanical ventilation, prone positioning and administration of neuromuscular blocking agents is limited. Recent studies have shown some benefits of corticosteroids (CS). Prolonged use of CS can shorten duration of mechanical ventilation, duration of hospitalization or improve oxygenation, probably because of a wide spectrum of potentially desired actions including anti-inflammatory, antioxidant, pulmonary vasodilator and anti-oedematous effects. However, the results from experimental vs. clinical studies as well as among the clinical trials are often controversial, probably due to differences in the designs of the trials. Thus, before the use of CS in ARDS can be definitively confirmed or refused, the additional studies should be carried on to determine the most appropriate dosing, timing and choice of CS and to analyse the potential risks of CS administration in various groups of patients with ARDS.

Disentanglement of functional complexity associated with plant mitogen-activated protein kinase (MAPK) signaling has benefited from transcriptomic, proteomic, phosphoproteomic, and genetic studies. Published transcriptomic analysis of a double homozygous recessive anp2anp3 mutant of two MAPK kinase kinase (MAPKKK) genes called Arabidopsis thaliana Homologues of Nucleus- and Phragmoplast-localized Kinase 2 (ANP2) and 3 (ANP3) showed the upregulation of stress-related genes. In this study, a comparative proteomic analysis of anp2anp3 mutant against its respective Wassilevskaja ecotype (Ws) wild type background is provided. Such differential proteomic analysis revealed overabundance of core enzymes such as FeSOD1, MnSOD, DHAR1, and FeSOD1-associated regulatory protein CPN20, which are involved in the detoxification of reactive oxygen species in the anp2anp3 mutant. The proteomic results were validated at the level of single protein abundance by Western blot analyses and by quantitative biochemical determination of antioxidant enzymatic activities. Finally, the functional network of proteins involved in antioxidant defense in the anp2anp3 mutant was physiologically linked with the increased resistance of mutant seedlings against paraquat treatment.

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Damage of alveolar-capillary barrier, inflammation, oxidative injury, and lung cell apoptosis represent the key features of acute lung injury (ALI). This study evaluated if selective phosphodiesterase (PDE)-4 inhibitor roflumilast can reduce the mentioned changes in lavage-induced model of ALI. Rabbits with ALI were divided into 2 groups: ALI without therapy (A group) and ALI treated with roflumilast i.v. (1 mg/kg; A+R group). One group of healthy animals without ALI served as ventilated controls (C group). All animals were oxygen-ventilated for further 4 h. At the end of experiment, total and differential counts of cells in bronchoalveolar lavage fluid (BALF) and total and differential counts of white blood cells were estimated. Lung edema formation was assessed from determination of protein content in BALF. Pro-inflammatory cytokines (TNFα, IL-6 and IL-8) and markers of oxidation (3-nitrotyrosine, thiobarbituric-acid reactive substances) were detected in the lung tissue and plasma. Apoptosis of lung cells was investigated immunohistochemically. Treatment with roflumilast reduced leak of cells, particularly of neutrophils, into the lung, decreased concentrations of cytokines and oxidative products in the lung and plasma, and reduced lung cell apoptosis and edema formation. Concluding, PDE4 inhibitor roflumilast showed potent anti-inflammatory actions in this model of ALI.

Inflammation associated with acute respiratory distress syndrome (ARDS) can damage the alveolar epithelium and surfactant and worsen the respiratory failure. Glucocorticoids (GC) appear to be a rational therapeutic approach, but the effect is still unclear, especially for early administration and low-dose. In this study we compared two low doses of dexamethasone in early phase of surfactant-depleted model of acute respiratory distress syndrome (ARDS). In the study, lung-lavaged New Zealand rabbits with respiratory failure (PaO2<26.7 kPa in FiO2 1.0) were treated with intravenous dexamethasone (DEX): 0.5 mg/kg (DEX-0.5) and 1.0 mg/kg (DEX-1.0), or were untreated (ARDS). Animals without ARDS served as controls. Respiratory parameters, lung edema, leukocyte shifts, markers of inflammation and oxidative damage in the plasma and lung were evaluated. Both doses of DEX improved the lung function vs. untreated animals. DEX-1.0 had faster onset with significant improvement in gas exchange and ventilation efficiency vs. DEX-0.5. DEX-1.0 showed a trend to reduce lung neutrophils, local oxidative damage, and levels of TNFα, IL-6, IL-8 more effectively than DEX-0.5 vs. ARDS group. Both dosages of dexamethasone significantly improved the lung function and suppressed inflammation in early phase ARDS, while some additional enhancement was observed for higher dose (1 mg/kg) of DEX.

Neonatal meconium aspiration syndrome (MAS) can be treated by exogenous surfactant (S). However, aspirated meconium initiates local inflammation and oxidation which may inactivate surfactant and reduce its action. This experimental study estimated whether combined use of surfactant and the antioxidant N-acetylcysteine (NAC) can enhance effectiveness of therapy. Meconium-instilled rabbits were non-treated (M), treated with monotherapies (M + S, M + NAC), combined therapy (M + S + NAC), or received saline instead of meconium (controls, C). Surfactant therapy consisted of two lung lavages (BAL) with diluted Curosurf (5 mg phospholipids/ml, 10 ml/kg) followed by undiluted Curosurf (100 mg phospholipids/kg). N-acetylcysteine (Acc Injekt, 10 mg/kg) was given intravenously in M + S + NAC group 10 min after surfactant therapy. Animals were oxygen-ventilated for additional 5 h. Then, differential white cell count in the blood (WBC) was determined. Left lung was saline-lavaged and differential cell count in BAL was determined. In right lung tissue, wet/dry weight ratio, oxidation markers (TBARS, 3NT) and interleukines (IL-2, IL-6, IL-13, and TNFα) using ELISA and RT-PCR were estimated. Combined S + NAC therapy significantly decreased W/D ratio, TBARS, 3NT, and IL, whereas the effect of monotherapies (either S or NAC) was less obvious. In conclusion, addition of NAC to surfactant treatment may enhance the therapeutic outcome in MAS.