Identification of Drugs Inducing Phospholipidosis by Novel in vitro Data

Abstract

Drug-induced phospholipidosis (PLD) is a lysosomal storage disorder characterized by the accumulation of phospholipids within the lysosome. This adverse drug effect can occur in various tissues and is suspected to impact cellular viability. Therefore, it is important to test chemical compounds for their potential to induce PLD during the drug design process. PLD has been reported to be a side effect of many commonly used drugs, especially those with cationic amphiphilic properties. To predict drug-induced PLD in silico, we established a high-throughput cell-culture-based method to quantitatively determine the induction of PLD by chemical compounds. Using this assay, we tested 297 drug-like compounds at two different concentrations (2.5 μm and 5.0 μm). We were able to identify 28 previously unknown PLD-inducing agents. Furthermore, our experimental results enabled the development of a binary classification model to predict PLD-inducing agents based on their molecular properties. This random forest prediction system yields a bootstrapped validated accuracy of 86 %. PLD-inducing agents overlap with those that target similar biological processes; a high degree of concordance with PLD-inducing agents was identified for cationic amphiphilic compounds, small molecules that inhibit acid sphingomyelinase, compounds that cross the blood–brain barrier, and compounds that violate Lipinski’s rule of five. Furthermore, we were able to show that PLD-inducing compounds applied in combination additively induce PLD.

Lysosomal Sequestration (Trapping) of Lipophilic Amine (Cationic Amphiphilic) Drugs in Immortalized Human Hepatocytes (Fa2N-4 Cells)

“…The development of drug-induced phospholipidosis in nonclinical species usually requires prolonged treatment with high doses of CADs, which are lipophilic amines that cannot only increase lysosomal pH but can bind tightly to phospholipids. This leads to the impediment of lysosomal-based catabolism of phospholipids through inhibition of acidic hydrolases and the endo-and exocytosis of endobiotics in and out of lysosomes as well as impeding lysosomal cycling (Daniel and Wojcikowski, 1999;Hanumegowda et al, 2010;Muehlbacher et al, 2012). Because of the strong association between lysosomal trapping of CADs and drug-induced phospholipidosis, screening approaches to identify lysosomotropic compounds will help to identify early in drug discovery those compounds with the potential to cause phospholipidosis.…”

Drug Discovery Methods for Studying Brain Drug Delivery and Distribution

“…Inhibition of acid sphingomyelinase results in anti-apoptotic, proliferative, and antiinflammatory effects. Consequently, functional acid sphingomyelinase inhibitors have potential in a number of new clinical therapies (Muehlbacher et al 2012). …”

Comparative analysis of lipotoxicity induced by endocrine, pharmacological, and innate immune stimuli in rat basophilic leukemia cells

“…Hyper-accumulation of mast cell LB in response to one of these (hyperinsulinemia) has been documented (Greineisen et al, 2012). However, it remains unclear whether hyperinsulinemia-driven steatotic LB accumulation in mast cells represents a lipotoxic phenotype; whether innate immune stimuli can in fact initiate LB accumulation in mast cells; whether exposure to CAD can drive the steatotic pathway; and whether phospholipidosis accompanies any of these lipotoxic responses (Halliwell, 1997; Anderson et al, 2006; Begriche et al, 2011; Muehlbacheret al, 2012; Park et al, 2012; Shayman et al, 2013). This paper seeks to address these questions.…”

“…PLD is a change in phospholipid metabolism that causes excess accumulation of phospholipids, distinguished by the production of intracellular multi-lammelar lysosomal bodies (Halliwell, 1997; Anderson et al, 2006; Begriche et al, 2011; Muehlbacher et al, 2012; Park et al, 2012; Shayman et al, 2013). A suggested mechanism for PLD involves the formation of a drug-phospholipid complex that inhibits phospholipases.…”

“…A suggested mechanism for PLD involves the formation of a drug-phospholipid complex that inhibits phospholipases. Cationic amphiphilic drugs can form these drug-lipid complexes (Muehlbacher et al, 2012). PLD represents a major problem in drug development pipelines.…”