Role of oxidative stress and mitophagy in the development of amiodarone-induced pulmonary fibrosis

Amiodarone (AD) is a bi-iodinated benzofuran derivative, classified as Class III anti-arrhythmic drug. Despite its therapeutic potential, AD inflicts several cardiac and extra-cardiac side effects. Being a cationic amphiphilic drug, AD exhibits high lipophilicity. This aids in the accumulation of the drug and its metabolite, N-desethylamiodarone (DEA) in high lipid containing organs viz adipose tissue, thyroid, liver, lungs and so on, thereby causing potentially harmful off-target effects. Although AD mediated thyroid and ophthalmic effects are more prevalent, AD-induced pulmonary toxicity (AIPT) is often fatal. Severe pulmonary toxicity has been reported in patients receiving even low doses of AD. Pulmonary fibrosis is one of the most frequently reported manifestations of AIPT. Although the precise molecular mechanism underlying AIPT still remains obscure, interplay between several direct and indirect mechanisms such as cytotoxic insult, immune mediated inflammatory process and angiotensin system activation might contribute towards the development of AIPT. Direct exposure to AD has been shown to induce apoptosis in various mammalian lung cell types including the human alveolar epithelial cells (AECs) in vitro. Apoptosis of alveolar epithelial cells (AECII) has been suggested to be a prime factor driving the development of pulmonary fibrosis. Collectively, the present study demonstrates that a) AD-induced AECII apoptosis is LC3B dependent and thus AD-induced macroautophagy is anti-survival in AECII b) AD increases oxidative stress and drives aberrant mitophagy via p62 resulting in AECII apoptosis c) AD-induced autophagy is HO-1 independent.Amiodaron (AD) ist ein bi-iodiniertes Benzofuran-Derivat welches als Klasse-III Antiarrhythmikum klassifiziert ist. Trotz des therapeutischen Potentials weist AD mehrere Nebenwirkungen innerhalb und außerhalb des Herz-Kreislaufs auf.Als kationisches amphiphiles Molekül ist AD hoch lipophil. Dies führt zur Anreichunerung des Moleküls und seines Metabolits, N-Desethylamiodaron (DEA) in Organen mit hohem Lipid-Anteil wie unter anderem Adiposem Gewebe, Schilddrüse, Leber und Lunge, welches potentiell schädliche Nebenwirkungen verursacht. Obwohl AD-vermittelte Effekte auf Schilddrüse und Sehorgane häufiger auftreten, ist AD verursachte Lungen-Toxizität (AIPT) häufig tödlich. Selbst in Patienten die nur geringe Mengen von AD zu sich genommen haben, wurde von schwerer Lungen-Toxizität berichtet.Lungenfibrose ist eine der am häufigsten gemeldeten Symptome von AIPT. Obwohl der genaue molekulare Mechanismus von AIPT noch unbekannt ist, kann die Entwicklung von AIPT durch Zusammenspiel von mehreren direkten und indirekten Mechanismen wie zytotoxische Schädigung, Immunsystem-basierte Entzündungsprozesse und Aktivierung des Angiotensin-Systems unterstützt werden. Es wurde gezeigt, dass direkte Exposition von AD in verschiedenen Säugetier-Lungen-Zelltypen wie humanen alveolaren Epithelzellen (AECs) in vitro Apoptose auslösen kann. Apoptose der alveolaren Epithelzellen (AECII) gilt als einer der wichtigsten Faktoren für die Entwicklung der Lungenfibrose. Zusammengefasst zeigt die aktuelle Studie, dass a) AD-induzierte AECII Apoptose LC3B-abhängig ist und damit AD-induzierte Makroautophagie einen Anti-Überlebensfaktor für AECII darstellt, b) AD den oxidativen Stress erhöht und anomale Mitophagie mittels p62 antreibt was in AECII Apoptose resultiert, c) AD-induzierte Autophagie HO-1 unabhängig ist

ToF-SIMS mediated analysis of human lung tissue reveals increased iron deposition in COPD (GOLD IV) patients

Chronic obstructive pulmonary disease (COPD) is a debilitating lung disease that is currently the third leading cause of death worldwide. Recent reports have indicated that dysfunctional iron handling in the lungs of COPD patients may be one contributing factor. However, a number of these studies have been limited to the qualitative assessment of iron levels through histochemical staining or to the expression levels of iron-carrier proteins in cells or bronchoalveolar lavage fluid. In this study, we have used time of flight secondary ion mass spectrometry (ToF-SIMS) to visualize and relatively quantify iron accumulation in lung tissue sections of healthy donors versus severe COPD patients. An IONTOF 5 instrument was used to perform the analysis, and further multivariate analysis was used to analyze the data. An orthogonal partial least squares discriminant analysis (OPLS-DA) score plot revealed good separation between the two groups. This separation was primarily attributed to differences in iron content, as well as differences in other chemical signals possibly associated with lipid species. Further, relative quantitative analysis revealed twelve times higher iron levels in lung tissue sections of COPD patients when compared to healthy donors. In addition, iron accumulation observed within the cells was heterogeneously distributed, indicating cellular compartmentalization

Acceptability of HIV Pre-Exposure Prophylaxis (PrEP) and Implementation Challenges Among Men Who Have Sex with Men in India: A Qualitative Investigation

Final publication is available from Mary Ann Liebert, Inc., publishers http://dx.doi.org/10.1089/apc.2015.0143.From publisher: This qualitative study explored the acceptability of HIV pre-exposure prophylaxis (PrEP) among MSM in India, and identified facilitators and barriers to future PrEP uptake. In 2014, we conducted 10 focus groups (n=61) among a purposive sample of diverse MSM recruited through community-based organizations in Chennai and Mumbai, and 10 key informant interviews with community leaders and health care providers. Participants' mean age was 26.1 years (SD 4.8); 62% completed secondary education, and 42% engaged in sex work. No focus group participants had heard of PrEP, but once explained, most reported they would likely use it. PrEP was alternately perceived as a ‘back-up plan’, a condom substitute, or a burden with concurrent condom use. Facilitators were potential for covert use, sex without condoms, and anxiety-less sex. Potential barriers emerged around stigma associated with PrEP use, fear of disclosures to one's family, wife, or male steady partner, and being labeled as HIV-positive or promiscuous by peers. Preferences emerged for intermittent rather than daily PrEP use, injectable PrEP, and free or subsidized access through community organizations or government hospitals. Key informants expressed additional concerns about risk compensation, non-adherence, and impact on ART availability for treatment. Demonstration projects are needed in India to support PrEP implementation tailored for at-risk MSM. Educational interventions for MSM should address concerns about PrEP effectiveness, side effects, and mitigate risk compensation. Community engagement may facilitate broad acceptability and challenge stigma around PrEP use. Importantly, provision of free or subsidized PrEP is necessary to making implementation feasible among low socioeconomic status MSM in India.This study was funded in part by grants from the Canadian Institutes of Health Research (MOP-102512; THA-118570) and the Canada Research Chairs Program

Molecular docking and structure-based virtual screening studies of potential drug target, CAAX prenyl proteases, of <i>Leishmania donovani</i>

<p>Targeting CAAX prenyl proteases of <i>Leishmania donovani</i> can be a good approach towards developing a drug molecule against Leishmaniasis. We have modeled the structure of CAAX prenyl protease I and II of <i>L. donovani</i>, using homology modeling approach. The structures were further validated using Ramachandran plot and ProSA. Active site prediction has shown difference in the amino acid residues present at the active site of CAAX prenyl protease I and CAAX prenyl protease II. The electrostatic potential surface of the CAAX prenyl protease I and II has revealed that CAAX prenyl protease I has more electropositive and electronegative potentials as compared CAAX prenyl protease II suggesting significant difference in their activity. Molecular docking with known bisubstrate analog inhibitors of protein farnesyl transferase and peptidyl (acyloxy) methyl ketones reveals significant binding of these molecules with CAAX prenyl protease I, but comparatively less binding with CAAX prenyl protease II. New and potent inhibitors were also found using structure-based virtual screening. The best docked compounds obtained from virtual screening were subjected to induced fit docking to get best docked configurations. Prediction of drug-like characteristics has revealed that the best docked compounds are in line with Lipinski’s rule. Moreover, best docked protein–ligand complexes of CAAX prenyl protease I and II are found to be stable throughout 20 ns simulation. Overall, the study has identified potent drug molecules targeting CAAX prenyl protease I and II of <i>L. donovani</i> whose drug candidature can be verified further using biochemical and cellular studies.</p

2-(3,4-Dimethoxyphenyl)-4,5-diphenyl-1-(prop-2-en-1-yl)-1H-imidazole

In the title compound, C26H24N2O2, the planar 1H-imidazole ring makes dihedral angles of 35.78&amp;#8197;(4), 26.35&amp;#8197;(5) and 69.75&amp;#8197;(5)&amp;#176;, respectively, with the dimethoxyphenyl ring and the phenyl rings in the 4- and 5-positions. In the crystal, C&amp;#8212;H...O hydrogen bonds connect neighbouring molecules, forming infinite chains running along the b axis. Furthermore, the crystal structure exhibits a C&amp;#8212;H-...&amp;#960; interaction between a methyl H atom and a phenyl ring from an adjacent molecule

Diversity of Sodium Transporter HKT1;5 in Genus Oryza

Asian cultivated rice shows allelic variation in sodium transporter, OsHKT1;5, correlating with shoot sodium exclusion (salinity tolerance). These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane (MPM) motifs in OsHKT1;5. HKT1;5 sequences from more recently evolved Oryza species (O. sativa/O. officinalis complex species) contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains, potentially governing transport characteristics, while more ancestral HKT1;5 sequences have shorter intracellular loops. We compared homology models for homoeologous OcHKT1;5-K and OcHKT1;5-L from halophytic O. coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+. Using haplotyping, we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species (O. nivara and O. rufipogon). Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance. Within Asian rice accessions, 10 non-synonymous HKT1;5 haplotypic groups occur. More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica. Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups, corresponding to haplotypes in O. sativa salt-sensitive and salt-tolerant landraces, respectively. This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica, or from different haplotypes selected during domestication. Predominance of specific HKT1;5 haplotypes within the 3 000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts