The interactions of cannabinoids with membranes as studied by DSC and solid state NMR

Abstrac

A Comparative Molecular Dynamics, MM−PBSA and Thermodynamic Integration Study of Saquinavir Complexes with Wild-Type HIV‑1 PR and L10I, G48V, L63P, A71V, G73S, V82A and I84V Single Mutants

A great challenge toward Acquired Immunodeficiency Syndrome (AIDS) treatment is to combat the HIV-1 virus. The major problem of drug resistance has kept the virus one step ahead of the medical community, and the call for more effective drugs remains as urgent as ever. Saquinavir, the first inhibitor against HIV-1 protease, offers the most extensive clinical data regarding resistance mutations. In this work, we examine L10I, G48V, L63P, A71V, G73S, V82A, and I84V single mutant HIV-1 PR strains in complexes with saquinavir to elucidate drug–protease interactions and dynamics. A comparative analysis of these mutations at the molecular level may lead to a deeper understanding of saquinavir resistance. The G48V mutation induces structural changes to the protease that reflect upon the drug’s binding affinity, as shown by MM–PBSA and thermodynamic integration (TI) calculations (ΔΔGTI = 0.3 kcal/mol; ΔΔGMM–PBSA = 1.2 kcal/mol). It was shown that mutations, which increase the flexibility of the flaps (G48V, L63P, L10I) diminish binding. The preservation of hydrogen bonds of saquinavir with both the active site and flap residues in the wild-type and certain single mutants (A71V, V82A) is also crucial for effective inhibition. It was shown that mutations conferring major resistance (G48V, L63P, I84V) did not present these interactions. Finally, it was indicated that a water-mediated hydrogen bond between saquinavir and Asp29 in the active site (wild-type, A71V, G73S) facilitates a proper placement of the drug into the binding cavity that favors binding. Mutants lacking this interaction (G48V, V82A, I84V) demonstrated reduced binding affinities. This systematic and comparative study is a contribution to the elucidation of the drug resistance mechanism in HIV-1 PR

Η Σημειολογία των αριθμών και των ωρών στο Κατά Ιωάννη Ευαγγέλιο

Στην παρούσα διδακτορική διατριβή διαπραγματεύεται η σημειολογία των αριθμών και ωρών που απαντούν στο Κατά Ιωάννη Ευαγγέλιο. Οι ερμηνείες οι οποίες καταγράφονται περιλαμβάνουν Πατέρες και Εκκλησιαστικούς συγγραφείς κατά προτεραιότητα της Ορθόδοξης Πίστης μας και δευτερευόντως άλλων δογμάτων. Επιπρόσθετα, συγκαταλέγονται οι ερμηνείες σύγχρονων Ελλήνων ερμηνευτών θεολόγων και της αλλοδαπής. Στόχος της διδακτορικής διατριβής είναι να εγκαθιδρυθεί μία συστηματική ανάλυση και μεθοδολογία στην ερμηνεία των αριθμών και ωρών η οποία πιθανόν να έχει προεκτάσεις και στην υπόλοιπο Αγία Γραφή. Πράγματι, τα συμπεράσματα τα οποία εξήχθησαν μπορούν να έχουν εφαρμογή κυρίως στα Καινοδιαθηκικά κείμενα αλλά ακόμη και σε κείμενα της Παλαιάς Διαθήκης. Τα κείμενα της Αγίας Γραφής προσφέρονται για πλουραλισμό ερμηνειών φτάνει αυτές να μην παρεκκλίνουν από το Χριστιανικό δόγμα και να μην οδηγούν σε πολυθεϊκές ή αντιθεϊκές ερμηνείες. Πιστεύουμε ότι τα συμπεράσματα τα οποία προέκυψαν σε κάθε εδάφιο το οποίο περιέχει αριθμό ή ώρα είναι σημαντικά. Ο πλουραλισμός σε αλληγορικές και μη ερμηνείες βοηθά στην κατανόηση της Αγιοπνευματικής ποικιλότητας, στον φωτισμό ανάλογα με το πνευματικό υπόβαθρο του μελετητή. Παρέχει επίσης ευδαιμονία και αγαλλίαση στον Πιστό γιατί κατανοεί ότι η Αγία Γραφή προσφέρεται ως πνευματική κλίμακα ανέλιξης με αμέτρητα σκαλοπάτια. Οι ανάλογες ερμηνείες βοηθούν τον Πιστό να ανελιχθεί στην πνευματική κλίμακα. Τέλος, θα πρέπει να σημειωθεί ότι σε πολλά εδάφια δόθησαν νέες ερμηνείες με βάση τα σύγχρονα δεδομένα τα οποία έφερε στο φως η επιστημονική γνώση. Αυτές οι νέες ερμηνείες δεν έρχονται σε αντίφαση ή ακυρώνουν αυτές των Αγίων Πατέρων της Ορθόδοξης Πίστης μας αλλά αντίθετα τις συμπληρώνουν.In this PhD dissertation, the semiology of the numbers and hours met in the Gospel of John is discussed. The interpretations recorded include Fathers and Ecclesiastical Writers as a priority of our Orthodox Faith and, secondarily, other doctrines. In addition, interpretations of contemporary theologians and the non-Greek are included. The aim of the PhD thesis is to establish a systematic analysis and methodology in interpreting the numbers and hours found in John Gosple which may have implication for the rest of the Bible as well. Indeed, the conclusions that have been excerpted can apply mainly to the New Testament texts, but even to texts in the Old Testament. The Bible texts lend themselves to pluralism of interpretations as far as they do not deviate form the Christian doctrine and lead to polytheic or antitheic interpretations. We believe that the conclusions that came out in each chapter containing a number or hour are important. Pluralism in allegorical and non-interpretations helps to understand the Spiritual diversity in lighting according to the scholar’s spiritual background. Finally, it should be noted that in many passages, new interpretations have been given on the basis of the modern data brought to light by scientific knowledge. These new interpretations do not contradict or invalidate those of the Holy Fathers of our Orthodox Faith but instead supplement them

Interactions of the dipeptide paralysin β-Ala-Tyr and the aminoacid Glu with phospholipid bilayers

AbstractExisting evidence points out that the biological activity of β-Ala-Tyr may in part related to its interactions with the cell membranes. For comparative reasons the effects of Glu were also examined using identical techniques and conditions. In order to examine their thermal and dynamic effects on membrane bilayers a combination of DSC, Raman and solid state NMR spectroscopy on DPPC/water model membranes were applied and the results were compared. DSC data showed that Glu perturbs to a greater degree the model membrane compared to β-Ala-Tyr. Thus, alteration of the phase transition temperature and half width of the peaks, abolishment of the pretransition and influence on the enthalpy of the phase transition were more pronounced in the Glu loaded bilayers. Raman spectroscopy showed that incorporation of Glu in DPPC/water bilayers increased the order in the bilayers in contrast to the effect of the dipeptide. Several structural and dynamical properties of the DPPC multilamellar bilayers with and without the dipeptide or Glu were compared using high resolution C-13 MAS (Magic Angle Spinning) spectra and spectral simulations of inhomogeneously broadened, stationary P-31 NMR lineshapes measured under CP (Cross-polarization) conditions. These methods revealed that the aminoacid Glu binds in the close realm of the phosphate in the hydrophilic headgroup of DPPC while β-Ala-Tyr is located more deeply inside the hydrophobic zone of the bilayer. The P-31 NMR simulations indicated restricted fast rotary motion of the phospholipids about their long axes in the organized bilayer structure. Finally, by the applied methodologies it is concluded that the two molecules under study exert dissimilar thermal and dynamic effects on lipid bilayers, the Glu improving significantly the packing of the lipids in contrast to the smaller and opposite effect of the dipeptide

The conformation of (-)-8α- and (-)-8α-hydroxy-Δ9-tetrahydrocannabinols and their interactions with model membranes.

8α- and 8β-Hydroxy-δ9-tetrahydrocannabinols (THC's), two metabolites of the naturally occurring δ9-THC have been shown to possess differences in pharmacological activity. We have studied the conformations of these two compounds, as well as their interactions with model membrane systems and compared them with δ9-THC. The conformational study, carried out in solution and using high resolution NMR indicated that differences in the ring conformations of these two compounds were negligible butthat the 8-hydroxy group of the 8β-OH compound extended approximately 1.4Å higher above the plane of the aromatic ring than in the 8α-OH isomer. This difference could prove significant in the interaction of these molecules with lipid bilayers. We found that both 8α- and 8β-OH analogs affected the melting behavior of hydrated DPPC bilayers including a lowering of the main transition temperature (Tc), a broadening of that transition and the abolishment of the pretransition of DPPC. The effects of the more active compound, 8β-OH-δ9-THC on the model membrane approximated closely those of δ9-THC, while the less active 8α-OH epimer produced different thermotropic changes

Small Peptides Able to Suppress Prostaglandin E₂ Generation in Renal Mesangial Cells.

Peptide drug discovery may play a key role in the identification of novel medicinal agents. Here, we present the development of novel small peptides able to suppress the production of PGE₂ in mesangial cells. The new compounds were generated by structural alterations applied on GK115, a novel inhibitor of secreted phospholipase A₂, which has been previously shown to reduce PGE₂ synthesis in rat renal mesangial cells. Among the synthesized compounds, the tripeptide derivative 11 exhibited a nice dose-dependent suppression of PGE₂ production, similar to that observed for GK115

Data2Game: Towards an Integrated Demonstrator

The Data2Game project investigates how the efficacy of computerized training games can be enhanced by tailoring training scenarios to the individual player. The research is centered around three research innovations: (1) techniques for the automated modelling of players’ affective states, based on exhibited social signals, (2) techniques for the automated generation of in-game narratives tailored to the learning needs of the player, and (3) validated studies on the relation of the player behavior and game properties to learning performance. This paper describes the integration of the main results into a joint prototype

Comparative study of the AT1 receptor prodrug antagonist candesartan cilexetil with other sartans on the interactions with membrane bilayers

AbstractDrug–membrane interactions of the candesartan cilexetil (TCV-116) have been studied on molecular basis by applying various complementary biophysical techniques namely differential scanning calorimetry (DSC), Raman spectroscopy, small and wide angle X-ray scattering (SAXS and WAXS), solution 1H and 13C nuclear magnetic resonance (NMR) and solid state 13C and 31P (NMR) spectroscopies. In addition, 31P cross polarization (CP) NMR broadline fitting methodology in combination with ab initio computations has been applied. Finally molecular dynamics (MD) was applied to find the low energy conformation and position of candesartan cilexetil in the bilayers. Thus, the experimental results complemented with in silico MD results provided information on the localization, orientation, and dynamic properties of TCV-116 in the lipidic environment. The effects of this prodrug have been compared with other AT1 receptor antagonists hitherto studied. The prodrug TCV-116 as other sartans has been found to be accommodated in the polar/apolar interface of the bilayer. In particular, it anchors in the mesophase region of the lipid bilayers with the tetrazole group oriented toward the polar headgroup spanning from water interface toward the mesophase and upper segment of the hydrophobic region. In spite of their localization identity, their thermal and dynamic effects are distinct pointing out that each sartan has its own fingerprint of action in the membrane bilayer, which is determined by the parameters derived from the above mentioned biophysical techniques

Application of 3D QSAR CoMFA/CoMSIA and in silico docking studies on novel renin inhibitors against cardiovascular diseases

For the first time, a set of renin inhibitors were subjected to the 3D QSAR/CoMFA and CoMSIA studies. The utility of renin inhibitors in the treatment of cardiovascular diseases has not been fully explored yet. At the moment, aliskiren is the first and only existing renin inhibitor in the drug market. The performed 3D QSAR/CoMFA and CoMSIA in combination with docking studies included aliskiren and 37 derivatives possessing a wide variety of bioactivity. The obtained results may aid in the design of novel bioactive renin inhibitors