Relationships Between Pharmacovigilance, Molecular, Structural, and Pathway Data: Revealing Mechanisms for Immune-Mediated Drug-Induced Liver Injury.

Immune-mediated drug-induced liver injury (IMDILI) can be devastating, irreversible, and fatal in the absence of successful transplantation surgery. We present a novel approach that combines the methods of pharmacoepidemiology with in silico molecular modeling to identify specific features in toxic ligands that are associated with clinical features of IMDILI. Specifically, from pharmacovigilance data multivariate logistic regression identified 18 drugs associated with IMDILI (P < 0.00015). Eleven of these drugs, along with their known and proposed metabolites, constituted a training set used to develop a four-point pharmacophore model (sensitivity 75%; specificity 85%). Subsequently, this information was combined with information from immune-pathway reviews and genetic-association studies and complemented with ligand-protein docking simulations to support a hypothesis implicating two putative targets within separate, possibly interacting, immune-system pathways: the major histocompatibility complex within the adaptive immune system and Toll-like receptors (TLRs), in particular TLR-7, which represent pattern recognition receptors of the innate immune system.

Corticosteroids and ß2-agonists upregulate mitogen-activated protein kinase phosphatase 1: in vitro mechanisms.

BACKGROUND AND PURPOSE: Airway remodelling is a consequence of long-term inflammation and MAPKs are key signalling molecules that drive pro-inflammatory pathways. The endogenous MAPK deactivator--MAPK phosphatase 1 (MKP-1)--is a critical negative regulator of the myriad pro-inflammatory pathways activated by MAPKs in the airway. EXPERIMENTAL APPROACH: Herein we investigated the molecular mechanisms responsible for the upregulation of MKP-1 in airway smooth muscle (ASM) by the corticosteroid dexamethasone and the ß2-agonist formoterol, added alone and in combination. KEY RESULTS: MKP-1 is a corticosteroid-inducible gene whose expression is enhanced by long-acting ß2-agonists in an additive manner. Formoterol induced MKP-1 expression via the ß2-adrenoceptor and we provide the first direct evidence (utilizing overexpression of PKIα, a highly selective PKA inhibitor) to show that PKA mediates ß2-agonist-induced MKP-1 upregulation. Dexamethasone activated MKP-1 transcription in ASM cells via a cis-acting corticosteroid-responsive region located between -1380 and -1266 bp of the MKP-1 promoter. While the 3'-untranslated region of MKP-1 contains adenylate + uridylate elements responsible for regulation at the post-transcriptional level, actinomycin D chase experiments revealed that there was no increase in MKP-1 mRNA stability in the presence of dexamethasone, formoterol, alone or in combination. Rather, there was an additive effect of the asthma therapeutics on MKP-1 transcription. CONCLUSIONS AND IMPLICATIONS: Taken together, these studies allow us a greater understanding of the molecular basis of MKP-1 regulation by corticosteroids and ß2-agonists and this new knowledge may lead to elucidation of optimized corticosteroid-sparing therapies in the future.

Calculation of the hydrophobicity of platinum drugs.

Models of the hydrophobicity of platinum drugs based on exposed surface areas of polar and nonpolar atoms are presented. For a total of 24 log P(oct) data, the best model resulted in a standard deviation of 0.35 over a range of more than 4 log units, with regression coefficients in broad agreement with previous models of log P(oct) for organic molecules. This model is used to compare log P(oct) to cell uptake for five platinum drugs and hence to establish an exponential relation between these parameters.

Molecular modelling and biological evaluation of a series of hydroxylated benzylideneanilines and benzylamines designed as tyrosine kinase inhibitors.

A series of hydroxylated benzylideneanilines and benzylamines were prepared and tested for inhibition of epidermal growth factor receptor-associated protein tyrosine kinase (PTK) activity in vitro. Molecular modelling and analysis of the biological results lead us to propose a minimal structural pharmacophore for two distinct binding sites within the PTK domain.