We report here that the novel protein kinase C isoform, PKC␦, is required at or prior to the level of the mitochondria for apoptosis induced by a diverse group of cell toxins. We have used adenoviral expression of a kinase-dead (KD) mutant of PKC␦ to explore the requirement for PKC␦ in the mitochondrial-dependent apoptotic pathway. Expression of PKC␦KD, but not PKC␣KD, in salivary epithelial cells resulted in a dosedependent inhibition of apoptosis induced by etoposide, UV-irradiation, brefeldin A, and paclitaxel. DNA fragmentation was blocked up to 71% in parotid C5 cells infected with the PKC␦KD adenovirus, whereas caspase-3 activity was inhibited up to 65%. The activation of caspase-9-like proteases by all agents was also inhibited in parotid C5 cells expressing PKC␦KD. The ability of PKC␦KD to block the loss of mitochondrial membrane potential was similarly determined. Expression of PKC␦KD blocked the decrease in mitochondrial membrane potential observed in cells treated with etoposide, UV, brefeldin A, or paclitaxel in a dose-dependent manner. In contrast to the protective function of PKC␦KD, expression of PKC␦WT resulted in a potent induction of apoptosis, which could be inhibited by coinfection with PKC␦KD. These results suggest that PKC␦ is a common intermediate in mitochondrial-dependent apoptosis in salivary epithelial cells.
BackgroundThe current Global initiative for chronic Obstructive Lung Disease (GOLD) treatment strategy recommends the use of one or more bronchodilators according to the patient’s airflow limitation, their history of exacerbations, and symptoms. The LANTERN study evaluated the effect of the long-acting β2-agonist (LABA)/long-acting muscarinic antagonist (LAMA) dual bronchodilator, QVA149 (indacaterol/glycopyrronium), as compared with the LABA/inhaled corticosteroid, salmeterol/fluticasone (SFC), in patients with moderate-to-severe COPD with a history of ≤1 exacerbation in the previous year.MethodsIn this double-blind, double-dummy, parallel-group study, 744 patients with moderate-to-severe COPD with a history of ≤1 exacerbations in the previous year were randomized (1:1) to QVA149 110/50 μg once daily or SFC 50/500 μg twice daily for 26 weeks. The primary endpoint was noninferiority of QVA149 versus SFC for trough forced expiratory volume in 1 second (FEV1) at week 26.ResultsOverall, 676 patients completed the study. The primary objective of noninferiority between QVA149 and SFC in trough FEV1 at week 26 was met. QVA149 demonstrated statistically significant superiority to SFC for trough FEV1 (treatment difference [Δ]=75 mL; P<0.001). QVA149 demonstrated a statistically significant improvement in standardized area under the curve (AUC) from 0 hours to 4 hours for FEV1 (FEV1 AUC0–4h) at week 26 versus SFC (Δ=122 mL; P<0.001). QVA149 and SFC had similar improvements in transition dyspnea index focal score, St George Respiratory Questionnaire total score, and rescue medication use. However, QVA149 significantly reduced the rate of moderate or severe exacerbations by 31% (P=0.048) over SFC. Overall, the incidence of adverse events was comparable between QVA149 (40.1%) and SFC (47.4%). The incidence of pneumonia was threefold lower with QVA149 (0.8%) versus SFC (2.7%).ConclusionThese findings support the use of the LABA/LAMA, QVA149 as an alternative treatment, over LABA/inhaled corticosteroid, in the management of moderate-to-severe COPD patients (GOLD B and GOLD D) with a history of ≤1 exacerbation in the previous year.
Protein kinase C delta (PKC delta) mediates apoptosis downstream of many apoptotic stimuli. Because of its ubiquitous expression, tight regulation of the proapoptotic function of PKC delta is critical for cell survival. Full-length PKC delta is found in all cells, whereas the catalytic fragment of PKC delta, generated by caspase cleavage, is only present in cells undergoing apoptosis. Here we show that full-length PKC delta transiently accumulates in the nucleus in response to etoposide and that nuclear translocation precedes caspase cleavage of PKC delta. Nuclear PKC delta is either cleaved by caspase 3, resulting in accumulation of the catalytic fragment in the nucleus, or rapidly exported by a Crm1-sensitive pathway, thereby assuring that sustained nuclear accumulation of PKC delta is coupled to caspase activation. Nuclear accumulation of PKC delta is necessary for caspase cleavage, as mutants of PKC delta that do not translocate to the nucleus are not cleaved. However, caspase cleavage of PKC delta per se is not required for apoptosis, as an uncleavable form of PKC delta induces apoptosis when retained in the nucleus by the addition of an SV-40 nuclear localization signal. Finally, we show that kinase negative full-length PKC delta does not translocate to the nucleus in apoptotic cells but instead inhibits apoptosis by blocking nuclear import of endogenous PKC delta. These studies demonstrate that generation of the PKC delta catalytic fragment is a critical step for commitment to apoptosis and that nuclear import and export of PKC delta plays a key role in regulating the survival/death pathway.
Tuberculous meningitis is a very serious form of tuberculosis. In the absence of randomized controlled trials of alternative treatment regimens, its management depends on employing potent drugs that penetrate well into the cerebrospinal fluid (CSF). The penetration of isoniazid, rifampin, and streptomycin into the CSF of 27 Chinese patients was studied using fluorimetric and microbiologic procedures. Isoniazid rapidly diffused into the CSF, peak concentrations in excess of 3 mg/L, or over 30 times its minimal inhibitory concentration (MIC) against Mycobacterium tuberculosis being attained within 4 hr. In contrast, rifampin and streptomycin penetrated very slowly across the meninges, and CSF levels only slightly in excess of their MICs against M. tuberculosis were achieved. The penetration of the drugs into the CSF correlated poorly with differences in their partitioning between octanol/water and cyclohexane/water but could be predicted using a simple model based on their renal clearance rates and plasma protein binding. It is recommended that patients with tuberculous meningitis should be treated for at least 9 months with a combination of isoniazid, rifampin, and pyrazinamide, which may be supplemented in the first 2 mo with streptomycin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.