Drug-induced phospholipidosis

The lipidome landscape of amiodarone toxicity: An in vivo lipid-centric multi-omics study

Amiodarone is an effective therapy for arrhythmias, its prolonged management may lead to significant adverse drug reactions. Amiodarone-induced hepatotoxicity is described by phospholipidosis, hepatic steatosis, cholestatic hepatitis, and cirrhosis. However, the systemic and hepatic lipidome disturbances and underlying toxicological mechanisms remain comprehensively elucidated. Untargeted lipidomics were utilized to analyze serum and liver samples from the rats orally administered a daily dose of amiodarone of either 100 or 300 mg/kg for one week. Changes in the expression of hepatic lipid-related genes were also examined utilizing transcriptomics. We found a higher magnitude of lipidome alterations in the 300 mg/kg than those in the 100 mg/kg groups. Treated animals showed elevated abundances of phosphatidylcholines, ether-linked phosphatidylcholines, sphingomyelins, and ceramides, and decreased levels of triacylglycerols, ether-linked triacylglycerols, and fatty acids. We also found 199 lipid-related differentially expressed hepatic genes between the 300 mg/kg group versus controls, implying lipid metabolism and signaling pathways disturbances. Specifically, elevation of serum phosphatidylcholines and ether-linked phosphatidylcholines, as well as hepatic bismonoacylglycerophosphates might be associated with reduced expression of phospholipase genes and elevated expression of glycerophospholipid biosynthesis genes, possibly driving phospholipidosis. Perturbations of sphingolipid metabolism might also be the key events for amiodarone-induced toxicity. Alterations in gene expression levels related to lipid storage and metabolism, mitochondria functions, and energy homeostasis were also found. Collectively, our study characterized the sophisticated perturbations in the lipidome and transcriptome of amiodarone-treated rats and suggested potential mechanisms responsible for amiodarone-induced hepatotoxicity.

Antibody-Drug Conjugates of NLRP3 Agonists: How Overcoming Lysosomal Accumulation Necessitated Noncanonical Linker Attachments

An initial series of NLRP3 agonist antibody-drug conjugates (ADCs) failed to induce IL-1β in vitro due to lysosomal trapping of the payload. To address this, we developed assays and computational tools to identify a new payload that could diffuse out of the lysosomes. ADCs derived from this payload were active, emphasizing the need to avoid payload lysosomal accumulation for nonlysosomal targets. Two active ADCs necessitated attaching a cleavable valine-citrulline recognition element to the payload via a noncanonical ester linkage, rather than a canonical carbamate one, since the payload did not contain a basic amine. The citrulline stereocenter configuration was found to affect the payload release and in vitro activity. The ADC with the (L)-Val-(L)-Cit ester configuration showed superior in vitro activity, high stability in mouse serum, and rapid cleavage in human liver lysosomes. These properties suggest that this noncanonical (L)-Val-(L)-Cit ester attachment may be valuable to the ADC community moving forward.

Key genes and processes affected by atorvastatin treatment in mouse diaphragm muscle

Statins are one of the top prescribed medications and are used for preventing or treating cardiovascular diseases. Myalgia, muscle fatigue, weakness, and inflammation are the most common side effects of these drugs collectively named statin-associated muscle symptoms (SAMS). The mechanisms underlying SAMS remain unclear. Given that statins inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme of mevalonate pathway, responsible for synthesis of cholesterol and other vital molecules, SAMS may be mediated by multiple reasons. Herein, using unbiased whole transcriptome sequencing, we identified statin-affected processes and then assessed them using fluorescent, biochemical, and histological approaches in the mouse diaphragm, the main respiratory muscle. Mice were orally treated for 1 month with atorvastatin, the most prescribed statin, at clinically relevant dose. We found that atorvastatin caused downregulation of genes encoding proteins required for oxidative phosphorylation and anabolic processes, whereas genes of proteins engaged inflammation and muscle atrophy were mainly up-regulated. Furthermore, alterations in gene expression pattern suggest oxidative stress and abnormal lipid accumulation. This transcriptome signature correlated to a decrease in mitochondrial polarization and protein synthesis capacity, as well as an increase in lipid peroxidation and reactive oxygen species production. In addition, atorvastatin treatment caused lipid raft disruption, phospholipidosis, myelin de-compactization, and appearance of greater heterogeneity of muscle fiber cross-section diameter. Thus, atorvastatin treatment can negatively affect diaphragm muscle via oxidative stress accompanied by decrease in mitochondrial activity, protein synthesis, and stability of plasma membrane. As a part of compensatory response can serve enhanced activity of superoxide dismutase and cholesterol uptake capacity.

Systematic Review of Neuropsychiatric Toxicity in Second Generation Antifungals With an Illustrative Case Report

BACKGROUND

Second-generation triazole antifungals are extended-spectrum drugs that act against yeasts, molds, and dimorphic fungi. These agents include voriconazole, posaconazole, and isavuconazole. Voriconazole may cause neuropsychiatric toxicity such as hallucinations. However, regarding neuropsychiatric toxicity related to posaconazole and isavuconazole, the literature remains poor.

OBJECTIVE

The present study reports a case of neuropsychiatric toxicity induced by posaconazole and isavuconazole triazole antifungals as well as the results of a systematic review on neuropsychiatric toxicity related to second-generation triazole antifungals.

METHODS

A systematic search of Medline electronic databases used MeSH headings and equivalent terms for second-generation triazole antifungals, delirium, hallucinations, and neurotoxicity. The selection of relevant records was performed by 2 independent reviewers. Epidemiological studies, observational studies, and case reports were included.

RESULTS

A total of 20 articles were included in the systematic review, comprising 11 case reports and 9 observational studies. All observational studies were related to voriconazole neuropsychiatric toxicity, particularly hallucinations; the estimated frequency of occurrence varied from 13.9% to 24%. Putative mechanisms of second-generation triazole antifungals neuropsychiatric toxicity include a disruption of cholesterol homeostasis in the brain, an inhibition of transient receptor potential melastatin 1 in retinal cells, and a drug-induced phospholiposis. A supra-therapeutic blood concentration of these agents as well as a drug interaction could also be involved.

CONCLUSIONS

In the present study, we reported for the first time, to our knowledge, a patient presenting with neuropsychiatric toxicity potentially related to posaconazole and isavuconazole. In a systematic review, we identified various mechanisms involved in the development of second-generation triazole antifungals neuropsychiatric toxicity. However, there remains to be extensive investigation.

The Non-Antibacterial Effects of Azithromycin and Other Macrolides on the Bronchial Epithelial Barrier and Cellular Differentiation

The respiratory epithelium maintains the barrier against inhaled harmful agents. When barrier failure occurs, as in several respiratory diseases, acute or chronic inflammation leading to destructive effects and exacerbations can occur. Macrolides are used to treat a spectrum of infections but are also known for off-label use. Some macrolides, particularly azithromycin (AZM), reduce exacerbations in chronic obstructive pulmonary disease (COPD), whereby its efficacy is thought to be due to its effects on inflammation and oxidative stress. In vitro data indicate that AZM reduces epithelial barrier failure, evidenced by increased transepithelial electrical resistance (TEER). Here, we compared the effects of macrolides on differentiation and barrier integrity in VA10 cells, a bronchial epithelial cell line for 14 and 21 days. Erythromycin, clarithromycin, roxithromycin, AZM, solithromycin, and tobramycin (an aminoglycoside) were analyzed using RNA sequencing, barrier integrity assays, and immunostaining to evaluate effects on the epithelium. All macrolides affected the gene expression of pathways involved in epithelial-to-mesenchymal transition, metabolism, and immunomodulation. Treatment with AZM, clarithromycin, and erythromycin raised TEER and induced phospholipid retention. AZM treatment was distinct in terms of enhancement of the epithelial barrier, retention of phospholipids, vesicle build-up, and its effect on gene sets related to keratinocyte differentiation and establishment of skin barrier.

Didecyldimethylammonium chloride-induced lung fibrosis may be associated with phospholipidosis

In the current study, we dosed didecyldimethylammonium chloride (DDAC) in mice by pharyngeal aspiration for 28 days or 90 days (weekly) and tried to elucidate the relationship between lamellar body formation and the lesions. When exposed for 28 days (0, 5, 10, 50, and 100 μg/head), all the mice in the 50 and 100 μg/head groups died since Day 2 after the third dosing (Day 16 after the first dosing). Edema, necrosis of bronchiolar and alveolar epithelium, and fibrinous exudate were observed in the lungs of all the dead mice, and chronic inflammatory lesions were observed in the lung tissues of alive mice. When dosed with DDAC of 0, 1, 4, and 8 μg/head for 13 weeks, the total number of pulmonary cells and the pulmonary levels of pro- and anti-inflammatory cytokines significantly increased, and chronic inflammatory lesions were detected with the production of collagen, collagen fibers, and lamellar body-like structures. Swelling of the nuclear envelope and nucleoplasmic components and generation of lipid droplets were also notably observed in the lung tissues of DDAC (8 μg/head)-treated mice. Furthermore, transcriptomic analysis performed using human bronchial epithelial cells showed that DDAC affected the expression of DNA damage, ER stress, lipid metabolism, and transcription regulation-related genes at 6 h after treatment, as it did 24 h treatment and that early growth response factor 1 gene was added to a list of the most up-regulated genes. Meanwhile, cytokines that are associated with the pathology of chronic lung diseases (IL-11, IL-24, and TGF-β) were slightly increased in the lung of DDAC-treated mice, and only the pulmonary level of CCL-2, but not CXCL-1 and CCL-3, increased in both sexes of mice. More importantly, the GM-CSF level increased dose-dependently in the lungs of both sexes of mice exposed to DDAC. Considering that the wound-healing process can take several weeks to complete, we suggest that DDAC-induced pulmonary fibrosis may be attributable to disruption of the wound-healing process due to continuous exposure to DDAC. We also hypothesize that the formation of lamellar bodies may be attributable to lysosomal accumulation of phospholipids separated from the destroyed lung tissue membrane.

European Society of Toxicologic Pathology-Pathology 2.0 Mass Spectrometry Imaging Special Interest Group: Mass Spectrometry Imaging in Diagnostic and Toxicologic Pathology for Label-Free Detection of Molecules-From Basics to Practical Applications

Mass Spectrometry Imaging (MSI) is a powerful tool to understand molecular pathophysiology and therapeutic and toxicity mechanisms, as well as for patient stratification and precision medicine. MSI, a label-free technique offering detailed spatial information on a large number of molecules in different tissues, encompasses various techniques including Matrix-Assisted Laser Desorption Ionization (MALDI), Desorption Electrospray Ionization (DESI), and Secondary Ion Mass Spectrometry (SIMS) that can be applied in diagnostic and toxicologic pathology. Given the utmost importance of high-quality samples, pathologists play a pivotal role in providing comprehensive pathobiology and histopathology knowledge, as well as information on tissue sampling, orientation, morphology, endogenous biomarkers, and pathogenesis, which are crucial for the correct interpretation of targeted experiments. This article introduces MSI and its fundamentals, and reports on case examples, determining the best suited technology to address research questions. High-level principles and characteristics of the most used modalities for spatial metabolomics, lipidomics and proteomics, sensitivity and specific requirements for sample procurement and preparation are discussed. MSI applications for projects focused on drug metabolism, nonclinical safety assessment, and pharmacokinetics/pharmacodynamics and various diagnostic pathology cases from nonclinical and clinical settings are showcased.

High Content Image Analysis of Cellular Responses of the Murine J774A.1 Cell Line and Primary Human Cells Alveolar Macrophages to an Extended Panel of Pharmaceutical Agents

INTRODUCTION

In vitro screening of macrophages for drug-induced effects, such as phospholipidosis, is useful for detecting potentially problematic compounds in the preclinical development of oral inhaled products. High-content image analysis (HCIA) is a multi-parameter approach for cytotoxicity screening. This study provides new insights into HCIA-derived response patterns of murine J774A.1 cells and primary human alveolar macrophages (hAM).

METHODS

Several compounds were compared with reference groups (cationic amphiphilic drugs and apoptosis inducers) at different concentrations (0.01 to 10 µM). After incubation, cells were stained with fluorescence markers and HCIA was performed (Cytation™ 5 Cell Imaging System). Ten parameters were analysed: non-adherent cells, increased or reduced mitochondrial activity, membrane permeability, cell area, nuclear area, polynucleated cells, vacuole area, neutral and phospholipid content. A new system of response categorisation was developed for data analysis.

RESULTS

Murine J774A.1 cells exhibited a drug-induced response pattern that was distinct to the corresponding pattern of hAM cells. Comparison with the literature revealed that primary cells (rat or human origin) have similar response patterns, while cell lines (mouse, rat or human) exhibited a different response pattern. Hierarchical clustering revealed toxicologically aligned clusters of compounds, suggesting potential use for understanding mechanisms of drug effects in cell lines and primary cells.

CONCLUSIONS

Valuable information for selecting a suitable cell type for HCIA screening of macrophage responses to drug compounds is provided. All cell types were suitable for screening drug-induced phospholipidosis. Still, human primary alveolar macrophages responded differently to drug treatment compared to macrophage cell lines and may be required to evaluate broader response-patterns and mechanisms of toxicity.

Glucosylceramide Synthase Inhibition in Combination with Aripiprazole Sensitizes Hepatocellular Cancer Cells to Sorafenib and Doxorubicin

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths due to its late diagnosis and restricted therapeutic options. Therefore, the search for appropriate alternatives to commonly applied therapies remains an area of high clinical need. Here we investigated the therapeutic potential of the glucosylceramide synthase (GCS) inhibitor Genz-123346 and the cationic amphiphilic drug aripiprazole on the inhibition of Huh7 and Hepa 1-6 hepatocellular cancer cell and tumor microsphere growth. Single and combinatorial treatments with both drugs at 5 µM concentration led to efficient cell cycle arrest, reduced expression of cyclins A and E, increased lipid storage in lysosomal compartments, accompanied by increased uptake of lysotracker, and elevated expression of the autophagy marker Lc3 II. Both drugs affected mitochondrial function, indicated by altered mitotracker uptake and impaired mitochondrial respiration. Aripiprazole in monotherapy, or even more pronounced in combination with Genz, also potentiated the effect of the cytostatic drugs sorafenib and doxorubicin on tumor cell- and tumor spheroid-growth inhibition. Targeting GCS with Genz with the parallel application of cationic amphiphilic drugs such as aripiprazole in combination with cytostatic drugs may thus represent a potent therapeutic approach in the treatment of HCC and potentially other cancer types.

Critical heart failure associated with beta-blocker-induced cardiac phospholipidosis: a case report

Background

Drug-induced phospholipidosis (DIPL) is an acquired lysosomal storage disorder characterized by the accumulation of lamellar bodies and phospholipids, typically associated with the use of cationic amphiphilic drugs (CADs). Over 200 marketed CADs, including widely prescribed β-blockers, have the potential to induce phospholipid deposition in various organs. In rare cases, DIPL may lead to secondary cardiomyopathy.

Case summary

We report the case of a 70-year-old man with a history of hypertension, permanent atrial fibrillation, and Stanford type B aortic dissection. The patient presented with a 2-week history of worsening dyspnoea. Examination revealed cardiomegaly, elevated B-type natriuretic peptide, and left ventricular dysfunction with an ejection fraction of 24%. Despite intensive medical treatment, the patient developed severe pulmonary congestion and died on Day 35. Post-mortem examination revealed vacuolar degeneration and lamellar body accumulation in the myocardium, consistent with DIPL. The most likely causal agent was bisoprolol, one of the patient's prescribed CADs.

Discussion

While β-blockers are commonly used for the treatment of hypertension and heart failure, their potential to induce phospholipid deposition in the heart is rare but significant. This case underscores the need for awareness of DIPL as a potential adverse effect, especially in patients receiving CADs.

The tyrosine kinase inhibitor Nintedanib induces lysosomal dysfunctionality: Role of protonation-dependent crystallization processes

Nintedanib (NIN), a multi-tyrosine kinase inhibitor clinically approved for idiopathic pulmonary fibrosis and lung cancer, is characterized by protonation-dependent lysosomotropic behavior and appearance of lysosome-specific fluorescence emission properties. Here we investigate whether spontaneous formation of a so far unknown NIN matter within the acidic cell compartment is underlying these unexpected emissive properties and investigate the consequences on lysosome functionality. Lysosomes of cells treated with NIN, but not non-protonatable NIN derivatives, exhibited lysosome-associated birefringence signals co-localizing with the NIN-derived fluorescence emission. Sensitivity of both parameters towards vATPase inhibitors confirmed pH-dependent, spontaneous adoption of novel crystalline NIN structures in lysosomes. Accordingly, NIN crystallization from buffer solutions resulted in formation of multiple crystal polymorphs with pH-dependent fluorescence properties. Cell-free crystals grown at lysosomal-like pH conditions resembled NIN-treated cell lysosomes concerning fluorescence pattern, photobleaching dynamics, and Raman spectra. However, differences in birefringence intensity and FAIM-determined anisotropy, as well as predominant association with (intra)lysosomal membrane structures, suggested formation of a semi-solid NIN crystalline matter in acidic lysosomes. Despite comparable target kinase inhibition, NIN, but not its non-protonatable derivatives, impaired lysosomal functionality, mediated massive cell vacuolization, enhanced autophagy, deregulated lipid metabolism, and induced atypical phospholipidosis. Moreover, NIN exerted distinct phototoxicity, strictly dependent on lysosomal microcrystallization events. The spontaneous formation of NIN crystalline structures was also observable in the gut mucosa of orally NIN-treated mice. Summarizing, the here-described kinase inhibition-independent impact of NIN on lysosomal functionality mediates several of its cell biological activities and might contribute to NIN adverse effects.

Livogrit prevents Amiodarone-induced toxicity in experimental model of human liver (HepG2) cells and Caenorhabditis elegans by regulating redox homeostasis

Treatment with cationic amphiphilic drugs like Amiodarone leads to development of phospholipidosis, a type of lysosomal storage disorder characterized by excessive deposition of phospholipids. Such disorder in liver enhances accumulation of drugs and its metabolites, and dysregulates lipid profiles, which subsequently leads to hepatotoxicity. In the present study, we assessed pharmacological effects of herbal medicine, Livogrit, against hepatic phospholipidosis-induced toxicity. Human liver (HepG2) cells and in vivo model of Caenorhabditis elegans (N2 and CF1553 strains) were used to study effect of Livogrit on Amiodarone-induced phospholipidosis. In HepG2 cells, Livogrit treatment displayed enhanced uptake of acidic pH-based stains and reduced phospholipid accumulation, oxidative stress, AST, ALT, cholesterol levels, and gene expression of SCD-1 and LSS. Protein levels of LPLA2 were also normalized. Livogrit treatment restored Pgp functionality which led to decreased cellular accumulation of Amiodarone as observed by UHPLC analysis. In C. elegans, Livogrit prevented ROS generation, fat-6/7 gene overexpression, and lysosomal trapping of Amiodarone in N2 strain. SOD-3::GFP expression in CF1553 strain normalized by Livogrit treatment. Livogrit regulates phospholipidosis by regulation of redox homeostasis, phospholipid anabolism, and Pgp functionality hindered by lysosomal trapping of Amiodarone. Livogrit could be a potential therapeutic intervention for amelioration of drug-induced phospholipidosis and prevent hepatotoxicity.

Low concentration cell painting images enable the identification of highly potent compounds

Image-based models that use features extracted from cell microscopy images can estimate the activity of small molecules in various biological assays. Typically, models are trained on images stained by an optimized protocol (e.g. Cell Painting) after exposure to a fairly high small molecule concentration (referred to as 'image concentration') of 10 μ M or higher. Low concentration images (e.g. 0.16 μM, 0.8 μM, 4 μM) tend to yield models with worse performance. In this work, we nevertheless report a practical use for low image concentration data. We propose the combination of well-performing models trained at higher image concentrations, with lower image concentration for inference to identify more potent compounds. We show that this approach improves on the conventional method (directly training a high-potency model) in 65 % of assays investigated in terms of AUC-ROC, and 75 % of assays in terms of RIPtoP-corrected AUC-PR.

Metabolic dysfunction-associated steatotic liver disease and drug-induced injuries: Pathogenetic aspects, treatment and prevention

Metabolic-associated fatty liver disease or metabolic dysfunction-associated steatotic liver disease is a common chronic disease  characterized by increased fat accumulation in the liver and underlying metabolic dysfunction. In the occurrence of this disease, cardiometabolic factors are important: dyslipidemia, impaired carbohydrate metabolism, insulin resistance, which increase as metabolic dysfunction- associated steatotic liver progresses and most often contribute to the development of cardiovascular pathology. Currently, metabolic dysfunction-associated steatotic liver is a multisystem disease associated with obesity, type 2 diabetes, cardiovascular diseases, chronic kidney disease, oncology, etc. Metabolic dysfunction- associated steatotic liver most often affects comorbid patients who take a considerable number of medications. Over the past decades, many drugs have been identified that have the potential to cause steatohepatitis in susceptible individuals. The range of drugs that have hepatotoxicity is quite large. More than 300 drugs are known to cause drug-induced liver injury. However, the true prevalence of drug-induced liver injury remains unknown, since it is not always possible to determine the true cause of liver damage or a specific drug. In this regard, the issue of management tactics for patients with metabolic dysfunction-associated steatotic liver and drug-induced liver injury remains relevant, especially when it comes to the need to take medications that are vital for the patient. The article provides a review of the literature on the etiopathogenetic, clinical and diagnostic aspects of both metabolic dysfunction-associated steatotic liver and in combination with drug-induced liver injury, features of the management of comorbid patients with metabolic dysfunction-associated steatotic liver and drug-induced liver injury. Therapeutic approaches are reviewed with an emphasis on comprehensive management (non-pharmacological and pharmacotherapy). Prescribing essential phospholipids may be effective in the treatment of such patients.

Intranasal Administration of Bedaquiline-Loaded Fucosylated Liposomes Provides Anti-Tubercular Activity while Reducing the Potential for Systemic Side Effects

Liposomal formulations of antibiotics for inhalation offer the potential for the delivery of high drug doses, controlled drug release kinetics in the lung, and an excellent safety profile. In this study, we evaluated the in vivo performance of a liposomal formulation for the poorly soluble, antituberculosis agent, bedaquiline. Bedaquiline was encapsulated within monodisperse liposomes of ∼70 nm at a relatively high drug concentration (∼3.6 mg/mL). Formulations with or without fucose residues, which bind to C-type lectin receptors and mediate a preferential binding to macrophage mannose receptor, were prepared, and efficacy was assessed in an in vivo C3HeB/FeJ mouse model of tuberculosis infection (H37Rv strain). Seven intranasal instillations of 5 mg/kg bedaquiline formulations administered every second day resulted in a significant reduction in lung burden (∼0.4-0.6 Δlog10 CFU), although no differences between fucosylated and nonfucosylated formulations were observed. A pharmacokinetic study in healthy, noninfected Balb/c mice demonstrated that intranasal administration of a single dose of 2.5 mg/kg bedaquiline liposomal formulation (fucosylated) improved the lung bioavailability 6-fold compared to intravenous administration of the same formulation at the same dose. Importantly, intranasal administration reduced systemic concentrations of the primary metabolite, N-desmethyl-bedaquiline (M2), compared with both intravenous and oral administration. This is a clinically relevant finding as the M2 metabolite is associated with a higher risk of QT-prolongation in predisposed patients. The results clearly demonstrate that a bedaquiline liposomal inhalation suspension may show enhanced antitubercular activity in the lung while reducing systemic side effects, thus meriting further nonclinical investigation.

Altered lipid homeostasis and autophagy precipitate diffuse alveolar hemorrhage in murine lupus

Abnormal autophagy regulation is implicated in lupus and other autoimmune diseases. We investigated autophagy in the murine pristane-induced lupus model. Pristane causes monocyte/macrophage-mediated endoplasmic reticulum (ER) stress in lung endothelial cells and diffuse alveolar hemorrhage (DAH) indistinguishable from DAH in lupus patients. Enlarged macrophages with abundant lipid droplets containing neutral lipid and exhibiting increased autophagosome staining were observed in the lung and peritoneal macrophages after pristane treatment. Cellular overload of neutral lipid can lead to selective autophagy (lipophagy) of lipid droplets and transport to lysosomes. The autophagy inducer rapamycin decreased neutral lipid staining but aggravated DAH, while an autophagy inhibitor (3-methyladenine) blocked the onset of DAH. Pristane-induced autophagy in macrophages was confirmed by acridine orange assay and LC3 western blot. Pristane also enlarged lysosomal volume and enhanced cathepsin S, D, and K expression while decreasing lysosomal acid lipase activity. If the capacity to degrade neutral lipid into free cholesterol and fatty acids is overwhelmed, lysosomes enlarge and can release cathepsins into the cytoplasm promoting cell death. Increasing lysosomal cholesterol content by blocking the Niemann-Pick C disease protein NPC1 protects against lysosome-dependent cell death. Treatment with NPC1 inhibitors U18666A or cepharanthine, which stabilize lysosomes, normalized lysosomal volume, reversed ER stress, and prevented DAH in pristane-treated mice. We conclude that pristane disrupts lipid homeostasis, promoting autophagy, lysosomal dysfunction, ER stress, and cell death leading to DAH. NPC1 inhibition reverses these abnormalities, preventing DAH. The findings shed light on the role of autophagy and lysosomal dysfunction in the pathogenesis of lupus.

Label-Free Screening of Drug-Induced Liver Injury Using Stimulated Raman Scattering Microscopy and Spectral Phasor Analysis

Hepatic toxicity is a leading cause of the termination of clinical trials and the withdrawal of therapeutics following regulatory approval. The detection of drug-induced liver injury (DILI) is therefore of importance to ensure patient safety and the effectiveness of novel small molecules and drugs. DILI encompasses drug-induced steatosis (DIS) and drug-induced phospholipidosis (DIPL) which involve the accumulation of excess intracellular lipids. Here, we develop hyperspectral stimulated Raman scattering (SRS) microscopy as a label-free methodology for discriminating DIS and DIPL in mammalian cell culture. We demonstrate that hyperspectral SRS imaging in tandem with spectral phasor analysis is capable of discriminating DIS and DIPL based on the nature and distribution of intracellular lipids resulting from each process. To demonstrate the practical application of this methodology, we develop a panel of alkyne-tagged propranolol analogues that display varying DILI effects. Using hyperspectral SRS imaging together with spectral phasor analysis, our label-free methodology corroborated the standard fluorescence-based assay for DILI. As a label-free screening method, it offers a convenient and expedient methodology for visualizing hepatotoxicity in cell cultures which could be integrated into the early stages of the drug development process for screening new chemical entities for DILI.

Sigma Receptor Ligands Are Potent Antiprion Compounds that Act Independently of Sigma Receptor Binding

Prion diseases are invariably fatal neurodegenerative diseases of humans and other animals for which there are no effective treatment options. Previous work from our laboratory identified phenethylpiperidines as a novel class of anti-prion compounds. While working to identify the molecular target(s) of these molecules, we unexpectedly discovered ten novel antiprion compounds based on their known ability to bind to the sigma receptors, σ1R and σ2R, which are currently being tested as therapeutic or diagnostic targets for cancer and neuropsychiatric disorders. Surprisingly, however, knockout of the respective genes encoding σ1R and σ2R (Sigmar1 and Tmem97) in prion-infected N2a cells did not alter the antiprion activity of these compounds, demonstrating that these receptors are not the direct targets responsible for the antiprion effects of their ligands. Further investigation of the most potent molecules established that they are efficacious against multiple prion strains and protect against downstream prion-mediated synaptotoxicity. While the precise details of the mechanism of action of these molecules remain to be determined, the present work forms the basis for further investigation of these compounds in preclinical studies. Given the therapeutic utility of several of the tested compounds, including rimcazole and haloperidol for neuropsychiatric conditions, (+)-pentazocine for neuropathic pain, and the ongoing clinical trials of SA 4503 and ANAVEX2-73 for ischemic stroke and Alzheimer's disease, respectively, this work has immediate implications for the treatment of human prion disease.

Double Hit of Hydroxichloroquine and Amiodarone Induced Renal Phospholipidosis in a Patient with Monoclonal Gammopathy and Sclerodermiform Syndrome: A Case Report and Review of the Literature

Phospholipidosis is a rare disorder which consists of an excessive intracellular accumulation of phospholipids and the appearance of zebra bodies or lamellar bodies when looking at them using electron microscopy. This disease is associated with certain genetic diseases or is secondary to drugs or toxins. Drug-induced phospholipidosis encompasses many types of pharmaceuticals, most notably chloroquine, amiodarone or ciprofloxacin. Clinically and histologically, renal involvement can be highly variable, with the diagnosis not being made until the zebra bodies are seen under an electron microscope. These findings may require genetic testing to discount Fabry disease, as its histological findings are indistinguishable. Most of the chemicals responsible are cationic amphiphilic drugs, and several mechanisms have been hypothesized for the formation of zebra bodies and their pathogenic significance. However, the relationship between drug toxicity and phospholipid accumulation, zebra bodies and organ dysfunction remains enigmatic, as do the renal consequences of drug withdrawal. We present, to our knowledge, the first case report of acute renal injury with a monoclonal gammopathy of renal significance, lesions, and sclerodermiform syndrome, with zebra bodies that were associated with the initiation of a hydroxychloroquine and amiodarone treatment, as an example of drug-induced-phospholipidosis.

Uncovering the toxicity mechanisms of a series of carboxylic acids in liver cells through computational and experimental approaches

Hepatotoxicity poses a significant concern in drug design due to the potential liver damage that can be caused by new drugs. Among common manifestations of hepatotoxic damage is lipid accumulation in hepatic tissue, resulting in liver steatosis or phospholipidosis. Carboxylic derivatives are prone to interfere with fatty acid metabolism and cause lipid accumulation in hepatocytes. This study investigates the toxic behaviour of 24 structurally related carboxylic acids in hepatocytes, specifically their ability to cause accumulation of fatty acids and phospholipids. Using high-content screening (HCS) assays, we identified two distinct lipid accumulation patterns. Subsequently, we developed structure-activity relationship (SAR) and quantitative structure-activity relationship (QSAR) models to determine relevant molecular substructures and descriptors contributing to these adverse effects. Additionally, we calculated physicochemical properties associated with lipid accumulation in hepatocytes and examined their correlation with our chemical structure characteristics. To assess the applicability of our findings to a wide range of chemical compounds, we employed two external datasets to evaluate the distribution of our QSAR descriptors. Our study highlights the significance of subtle molecular structural variations in triggering hepatotoxicity, such as the presence of nitrogen or the specific arrangement of substitutions within the carbon chain. By employing our comprehensive approach, we pinpointed specific molecules and elucidated their mechanisms of toxicity, thus offering valuable insights to guide future toxicology investigations.

Hybrid similarity relation based mutual information for feature selection in intuitionistic fuzzy rough framework and its applications

Fuzzy rough entropy established in the notion of fuzzy rough set theory, which has been effectively and efficiently applied for feature selection to handle the uncertainty in real-valued datasets. Further, Fuzzy rough mutual information has been presented by integrating information entropy with fuzzy rough set to measure the importance of features. However, none of the methods till date can handle noise, uncertainty and vagueness simultaneously due to both judgement and identification, which lead to degrade the overall performances of the learning algorithms with the increment in the number of mixed valued conditional features. In the current study, these issues are tackled by presenting a novel intuitionistic fuzzy (IF) assisted mutual information concept along with IF granular structure. Initially, a hybrid IF similarity relation is introduced. Based on this relation, an IF granular structure is introduced. Then, IF rough conditional and joint entropies are established. Further, mutual information based on these concepts are discussed. Next, mathematical theorems are proved to demonstrate the validity of the given notions. Thereafter, significance of the features subset is computed by using this mutual information, and corresponding feature selection is suggested to delete the irrelevant and redundant features. The current approach effectively handles noise and subsequent uncertainty in both nominal and mixed data (including both nominal and category variables). Moreover, comprehensive experimental performances are evaluated on real-valued benchmark datasets to demonstrate the practical validation and effectiveness of the addressed technique. Finally, an application of the proposed method is exhibited to improve the prediction of phospholipidosis positive molecules. RF(h2o) produces the most effective results till date based on our proposed methodology with sensitivity, accuracy, specificity, MCC, and AUC of 86.7%, 90.1%, 93.0% , 0.808, and 0.922 respectively.

Drug repurposing platform for deciphering the druggable SARS-CoV-2 interactome

The coronavirus disease 2019 (COVID-19) pandemic has heavily challenged the global healthcare system. Despite the vaccination programs, the new virus variants are circulating. Further research is required for understanding of the biology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and for discovery of therapeutic agents against the virus. Here, we took advantage of drug repurposing to identify if existing drugs could inhibit SARS-CoV-2 infection. We established an open high throughput platform for in vitro screening of drugs against SARS-CoV-2 infection. We screened ∼1000 drugs for their ability to inhibit SARS-CoV-2-induced cell death in the African green monkey kidney cell line (Vero-E6), analyzed how the hit compounds affect the viral N (nucleocapsid) protein expression in human cell lines using high-content microscopic imaging and analysis, determined the hit drug targets in silico, and assessed their ability to cause phospholipidosis, which can interfere with the viral replication. Duvelisib was found by in silico interaction assay as a potential drug targeting virus-host protein interactions. The predicted interaction between PARP1 and S protein, affected by Duvelisib, was further validated by immunoprecipitation. Our results represent a rapidly applicable platform for drug repurposing and evaluation of the new emerging viruses' responses to the drugs. Further in silico studies help us to discover the druggable host pathways involved in the infectious cycle of SARS-CoV-2.

Amiodarone-Associated Optic Neuropathy in a Patient With Associated Arrhythmia

Amiodarone is a commonly used antiarrhythmic used to treat atrial fibrillation and ventricular tachycardias. While this agent can present with pulmonary, thyroid, and hepatic side effects, it can also, less commonly cause neurologic toxicity, particularly optic neuropathy. Optic neuropathy can manifest as acute vision loss. The management of amiodarone-associated optic neuropathy (AAON) includes early recognition of symptom manifestation so that the medication can be discontinued promptly. Here, we describe a case of a 64-year-old male who developed acute onset complete left-sided vision loss after initiation of amiodarone.

Hydroxychloroquine-Induced Renal Phospholipidosis: Case Report and Review of Differential Diagnoses

Introduction

Renal phospholipidosis describes the accumulation of phospholipids in the lysosomes of kidney cells, in particular podocytes. Originally, this was described primarily in the context of the lysosomal storage disorder Fabry disease. It is now known that a variety of drugs can lead to the accumulation of lysosomal phospholipids.

Case Presentation

We present the case of a 69-year-old female patient suffering chronic kidney disease and systemic lupus erythematosus who underwent a kidney biopsy because of a further increase in serum creatinine levels. There was no evidence of lupus nephritis, but electron microscopy showed zebra bodies as a morphological sign of phospholipidosis. This was most likely drug-induced after 25 years of continuous medication with hydroxychloroquine. A renal biopsy 2 years and 6 months earlier, when the renal function of the patient was distinctively better, showed no signs of renal phospholipidosis. Afterward, medication with hydroxychloroquine was discontinued, and renal function parameters remained stable in the 1-year course.

Conclusion

This case raises the question of how severely impaired renal function affects the risk of hydroxychloroquine-induced renal phospholipidosis and underlines that hydroxychloroquine should be administered with caution in patients with kidney insufficiency. Moreover, we provide a review of the causes of renal phospholipidosis, which have been described in the literature and give an overview of possible differential diagnoses in cases with histologically proven phospholipidosis in renal biopsies.

Retinopathy Associated With Ritonavir Treatment for HIV Infection: A Case Series Reappraisal in the COVID-19 Era

Purpose: To report 3 cases of retinopathy secondary to ritonavir use in the treatment of HIV. Methods: A retrospective review of patient records was performed for data including ophthalmic examination findings, demographic and HIV clinical characteristics, and progression of maculopathy disease. The review identified 3 patients with a history of HIV treated with antiretroviral therapy including ritonavir who had been evaluated for bilateral vision loss in both eyes. Results: A fundus examination of each patient revealed characteristic macular atrophy, and optical coherence tomography demonstrated corresponding central outer retinal atrophy. Uveitis workup results were unremarkable. Given the characteristics of macular atrophy, history of ritonavir use, and the absence of intraocular inflammation, all 3 patients were diagnosed with bilateral ritonavir-associated retinopathy. Each patients' vision continued to deteriorate, even after the cessation of ritonavir. Conclusions: Ritonavir toxicity should be considered in the differential diagnosis of retinopathy among patients with an exposure history.

A machine learning and live-cell imaging tool kit uncovers small molecules induced phospholipidosis

Drug-induced phospholipidosis (DIPL), characterized by excessive accumulation of phospholipids in lysosomes, can lead to clinical adverse effects. It may also alter phenotypic responses in functional studies using chemical probes. Therefore, robust methods are needed to predict and quantify phospholipidosis (PL) early in drug discovery and in chemical probe characterization. Here, we present a versatile high-content live-cell imaging approach, which was used to evaluate a chemogenomic and a lysosomal modulation library. We trained and evaluated several machine learning models using the most comprehensive set of publicly available compounds and interpreted the best model using SHapley Additive exPlanations (SHAP). Analysis of high-quality chemical probes extracted from the Chemical Probes Portal using our algorithm revealed that closely related molecules, such as chemical probes and their matched negative controls can differ in their ability to induce PL, highlighting the importance of identifying PL for robust target validation in chemical biology.

Perturbations in lipid metabolism and gut microbiota composition precede cardiac dysfunction in a mouse model of thalassemia

Cardiomyopathy is a major complication of thalassemia, yet the precise underlying molecular mechanisms remain unclear. We examined whether altered lipid metabolism is an early driving factor in the development of cardiomyopathy using the Th3/+ mouse model of thalassemia. At age 20 weeks, male and female Th3/+ mice manifested anemia and iron overload; however, only males displayed metabolic defects and altered cardiac function. Untargeted lipidomics indicated that the circulating levels of 35 lipid species were significantly altered in Th3/+ mice compared to wild-type controls: triglycerides (TGs) with saturated fatty acids (FAs; TG42:0 and TG44:0) were elevated, while TGs with unsaturated FAs (TG(18:2_20:5_18:2 and TG54:8)) were reduced. Similarly, phosphatidylcholines (PCs) with long chain FAs (palmitic (16:0) or oleic (18:1)) were increased, while PCs with polyunsaturated FAs decreased. Circulating PC(16:0_14:0), GlcCer(d18:1/24:0) correlated significantly with iron overload and cardiac hypertrophy. 16S rRNA gene profiling revealed alterations in the intestinal microbiota of Th3/+ mice. Differentially abundant bacterial genera correlated with PC(39:6), PC(18:1_22:6), GlcCer(d18:1/24:1) and CE(14:0). These results provide new knowledge on perturbations in lipid metabolism and the gut microbiota of Th3/+ mice and identify specific factors which may represent early biomarkers or therapeutic targets to prevent development of cardiomyopathy in β-thalassemia.

Sigma receptor ligands are potent anti-prion compounds that act independently of sigma receptor binding

Prion diseases are invariably fatal neurodegenerative diseases of humans and other animals for which there are no treatment options. Previous work from our laboratory identified phenethyl piperidines as novel class of anti-prion compounds. While working to identify the molecular target(s) of these molecules, we unexpectedly discovered ten novel anti-prion compounds based on their known ability to bind to the sigma receptors, σ 1 R and 2 R, which are currently being tested as therapeutic or diagnostic targets for cancer and neuropsychiatric disorders. Surprisingly, however, knockout of the respective genes encoding σ 1 R and σ 2 R ( Sigmar1 and Tmem97 ), in prion infected N2a cells did not alter the anti-prion activity of these compounds, demonstrating that these receptors are not the direct targets responsible the anti-prion effects of their ligands. Further investigation of the most potent molecules established that they are efficacious against multiple prion strains and protect against downstream prion-mediated synaptotoxicity. While the precise details of the mechanism of action of these molecules remains to be determined, the present work forms the basis for further investigations of these compounds in pre-clinical studies. Given the therapeutic utility of several of the tested compounds, including rimcazole and haloperidol for neuropsychiatric conditions, (+)-pentazocine for neuropathic pain, and the ongoing clinical trials of SA 4503 and ANAVEX2-73 for ischemic stroke and Alzheimer's disease, respectively, this work has immediate implications for the treatment of human prion disease.

Hepatic ultrastructural alterations induced by copper oxide nanoparticles: In vivo electron microscopy study

Copper oxide nanomaterials (CuO NPs) have been widely utilized in many fields, including antibacterial materials, anti-tumor, osteoporosis treatments, imaging, drug delivery, cosmetics, lubricants for metallic coating, the food industry, and electronics. Little is known about the potential risk to human health and ecosystems. The present work was conducted to investigate the ultrastructural changes induced by 20 ± 5 nm CuO NPs in hepatic tissues. Adult healthy male Wister albino rats were exposed to 36 intraperitoneal (ip) injections of 25 nm CuO NPs (2 mg/kg bw). Liver biopsies from all rats under study were processed for transmission electron microscopy (TEM) processing and examination for hepatic ultrastructural alterations. The hepatic tissue of rats exposed to repeated administrations of CuO NPs exhibited the following ultrastructural alterations: extensive mitochondrial damage in the form of swelling, crystolysis and matrix lysis, formation of phagocytized bodies and myelin multilayer figures, lysosomal hyperplasia, cytoplasmic degeneration and vacuolation, fat globules precipitation, chromatin clumping, and nuclear envelope irregularity. The findings indicated that CuO NPs interact with the hepatic tissue components and could induce alterations in the hepatocytes with the mitochondria as the main target organelles of copper nanomaterials. More work is recommended for better understanding the pathogenesis of CuO NPs.

Quantitative Raman chemical imaging of intracellular drug-membrane aggregates and small molecule drug precipitates in cytoplasmic organelles

Raman confocal microscopes have been used to visualize the distribution of small molecule drugs within different subcellular compartments. This visualization allows the discovery, characterization, and detailed analysis of the molecular transport phenomena underpinning the Volume of Distribution - a key parameter governing the systemic pharmacokinetics of small molecule drugs. In the specific case of lipophilic small molecules with large Volumes of Distribution, chemical imaging studies using Raman confocal microscopes have revealed how weakly basic, poorly soluble drug molecules can accumulate inside cells by forming stable, supramolecular complexes in association with cytoplasmic membranes or by precipitating out within organelles. To study the self-assembly and function of the resulting intracellular drug inclusions, Raman chemical imaging methods have been developed to measure and map the mass, concentration, and ionization state of drug molecules at a microscopic, subcellular level. Beyond the field of drug delivery, Raman chemical imaging techniques relevant to the study of microscopic drug precipitates and drug-lipid complexes which form inside cells are also being developed by researchers with seemingly unrelated scientific interests. Highlighting advances in data acquisition, calibration methods, and computational data management and analysis tools, this review will cover a decade of technological developments that enable the conversion of spectral signals obtained from Raman confocal microscopes into new discoveries and information about previously unknown, concentrative drug transport pathways driven by soluble-to-insoluble phase transitions occurring within the cytoplasmic organelles of eukaryotic cells.

Case report of progressive renal dysfunction as a consequence of amiodarone-induced phospholipidosis

Background

Amiodarone is associated with a range of unwanted effects on pulmonary, thyroid, and liver function. However, the nephrotoxic side effect caused by renal phospholipidosis has hardly received any attention up to now.

Case summary

This is a case of an 86-year-old Caucasian male with an acute on chronic kidney disease 4 months after the initiation of amiodarone. A renal biopsy demonstrated the intracellular accumulation of phospholipids that have previously been demonstrated in association with organ dysfunction because of amiodarone use. Serum creatinine levels subsequently improved from 388 to 314 µmol/L after stopping amiodarone over the course of 2 months.

Discussion

In this case, a diagnosis of partially reversible acute on chronic kidney disease caused by lysosomal phospholipidosis due to amiodarone use was deemed highly likely. Lysosomal dysfunction leads to the accumulation of intra-lysosomal phospholipids (phospholipidosis). This accumulation is accompanied by progressive organ damage and dysfunction, including renal dysfunction, in rare instances. Guidelines advise regular surveillance for liver, lung, and thyroid toxicity during amiodarone treatment but do not mention the potential for renal toxicity. This case suggests that it might be prudent to include screening for renal toxicity in this surveillance.

Profiling alveolar macrophage responses to inhaled compounds using in vitro high content image analysis

One of the main hurdles in the development of new inhaled medicines is the frequent observation of foamy macrophage (FM) responses in non-clinical studies in experimental animals, which raises safety concerns and hinders progress into clinical trials. We have investigated the potential of a novel multi-parameter high content image analysis (HCIA) assay as an in vitro safety screening tool to predict drug induced FM. Rat (NR8383) and human U937-derived alveolar macrophages were exposed in vitro to a panel of model compounds with different biological activity, including inhaled bronchodilators, inhaled corticosteroids (ICS), phospholipidosis inducers and proapoptotic agents. An HCIA was utilized to produce drug-induced cell response profiles based on individual cell health, morphology and lipid content parameters. The profiles of both rat and human macrophage cell lines differentiated between cell responses to marketed inhaled drugs and compounds known to induce phospholipidosis and apoptosis. Hierarchical clustering of the aggregated data allowed identification of distinct cell profiles in response to exposure to phospholipidosis and apoptosis inducers. Additionally, in NR8383 cell responses formed two distinct clusters, associated with increased vacuolation with or without lipid accumulation. U937 cells presented a similar trend but appeared less sensitive to drug exposure and presented a narrower range of responses. These results indicate that our multi-parameter HCIA assay is suitable to generate characteristic drug-induced macrophage response profiles, thus enabling differentiation of foamy macrophage phenotypes associated with phospholipidosis and apoptosis. This approach shows great potential as pre-clinical in vitro screening tool for safety assessment of candidate inhaled medicines.

Off target toxicities and links with physicochemical properties of medicinal products, including antibiotics, oligonucleotides, lipid nanoparticles (with cationic and/or anionic charges). Data review suggests an emerging pattern

Toxicology is an essential part of any drug development plan. Circumnavigating the risk of failure because of a toxicity issue can be a challenge, and failure in late development is extremely costly. To identify potential risks, it requires more than just understanding the biological target. The toxicologist needs to consider a compound's structure, it's physicochemical properties (including the impact of the overall formulation), as well as the biological target (e.g., receptor interactions). Understanding the impact of the physicochemical properties can be used to predict potential toxicities in advance by incorporating key endpoints in early screening strategies and/or used to compare toxicity profiles across lead candidates. This review discussed the risks of off-target and/or non-specific toxicities that may be associated with the physicochemical properties of compounds, especially those carrying dominant positive or negative charges, including amphiphilic small molecules, peptides, oligonucleotides and lipids/liposomes/lipid nanoparticles. The latter of which are being seen more and more in drug development, including the recent Covid pandemic, where mRNA and lipid nanoparticle technology is playing more of a role in vaccine development. The translation between non-clinical and clinical data is also considered, questioning how a physicochemical driven toxicity may be more universal across species, which means that such toxicity may be reassuringly translatable between species and as such, this information may also be considered as a support to the 3 R's, particularly in the early screening stages of a drug development plan.

Lysosomal trapping of 4-dimethylamino-1-{3-(1-methyl-1H-imidazole-2-yl)propanoyl}piperidine, a hydrophilic and weakly basic amine, in human aortic vascular smooth muscle cells

Some weakly basic compounds lead to cell death accompanied by cellular vacuolation. The novel analgesic agent, 4-dimethylamino-1-{3-(1-methyl-1H-imidazole-2-yl)propanoyl}piperidine (DMIP), is a hydrophilic and weakly basic compound that induces vacuolation in the vascular smooth muscle cells in dogs. Here, we investigated the vacuolation mechanism and the potential cytotoxicity of DMIP using human aortic vascular smooth muscle cells. When cells were treated with DMIP (0.1, 0.3, and 1 mM) for 6, 24, and 48 h, clear cytoplasmic vacuolation was observed at 1 mM after 24 and 48 h, along with an increase in the intracellular DMIP concentration. The vacuolation and intracellular DMIP were markedly reduced by bafilomycin A1, a vacuolar H⁺-ATPase inhibitor. The late endosome marker Rab7 and lysosome marker LAMP-2 were highly expressed but the early endosome marker Rab5 and autophagosome marker LC3 were not expressed specifically on the vacuolar membranes. These results suggested that the most vacuoles were enlarged late endosomes/lysosomes, resulting from the accumulation of DMIP by ion trapping. Moreover, DMIP did not affect lysosomal membrane integrity and was less cytotoxic than chloroquine, an inducer of phospholipidosis. The current study provides further insight into the mechanisms of vacuolation and lysosomal trapping induced by the hydrophilic and weakly basic amine DMIP.

Sub-cellular sequestration of alkaline drugs in lysosomes: new insights for pharmaceutical development of lysosomal fluid

Background and purpose

Lysosomal-targeted drug delivery can open a new strategy for drug therapy. However, there is currently no universally accepted simulated or artificial lysosomal fluid utilized in the pharmaceutical industry or recognized by the United States Pharmacopeia (USP).

Experimental procedure

We prepared a simulated lysosomal fluid (SLYF) and compared its composition to a commercial artificial counterpart. The developed fluid was used to test the dissolution of a commercial product (Robitussin^®) of a lysosomotropic drug (dextromethorphan) and to investigate in-vitro lysosomal trapping of two model drugs (dextromethorphan and (+/-) chloroquine).

Findings/Results

The laboratory-prepared fluid or SLYF contained the essential components for the lysosomal function in concentrations reflective of the physiological values, unlike the commercial product. Robitussin^® passed the acceptance criteria for the dissolution of dextromethorphan in 0.1 N HCl medium (97.7% in less than 45 min) but not in the SLYF or the phosphate buffer media (72.6% and 32.2% within 45 min, respectively). Racemic chloroquine showed higher lysosomal trapping (51.9%) in the in-vitro model than dextromethorphan (28.3%) in a behavior supporting in-vivo findings and based on the molecular descriptors and the lysosomal sequestration potential of both.

Conclusion and implication

A standardized lysosomal fluid was reported and developed for in-vitro investigations of lysosomotropic drugs and formulations.

Kidney Podocyte Zebra Bodies after Lung Transplantation for Lymphangioleiomyomatosis

A 55-year-old woman showed progressive renal dysfunction after unilateral deceased-donor lung transplantation for lymphangioleiomyomatosis. A kidney biopsy showed a striped pattern of interstitial fibrosis, suggesting calcineurin inhibitor toxicity, and zebra body accumulation was found predominantly in the podocytes, characteristics of Fabry disease. Nevertheless, she had no extra-renal symptoms of the disease, and gene testing identified no known mutation or exon deletion. Our case report and literature review suggest that this atypical lysosomal inclusion may be phospholipidosis induced by sertraline. Potential underlying etiologies linking zebra body deposits may be not only hereditary but also drug-induced phospholipidosis.

In Vitro Models for Studying Chronic Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major clinical problem in terms of patient morbidity and mortality, cost to healthcare systems and failure of the development of new drugs. The need for consistent safety strategies capable of identifying a potential toxicity risk early in the drug discovery pipeline is key. Human DILI is poorly predicted in animals, probably due to the well-known interspecies differences in drug metabolism, pharmacokinetics, and toxicity targets. For this reason, distinct cellular models from primary human hepatocytes or hepatoma cell lines cultured as 2D monolayers to emerging 3D culture systems or the use of multi-cellular systems have been proposed for hepatotoxicity studies. In order to mimic long-term hepatotoxicity in vitro, cell models, which maintain hepatic phenotype for a suitably long period, should be used. On the other hand, repeated-dose administration is a more relevant scenario for therapeutics, providing information not only about toxicity, but also about cumulative effects and/or delayed responses. In this review, we evaluate the existing cell models for DILI prediction focusing on chronic hepatotoxicity, highlighting how better characterization and mechanistic studies could lead to advance DILI prediction.

Multi-omics analysis unravels dysregulated lysosomal function and lipid metabolism involved in sub-chronic particulate matter-induced pulmonary injury

Particulate matter (PM) is a huge environmental threat and is of major public concern. Oxidative stress and systemic inflammation are known factors that contribute to PM- related damage; however, a systematic understanding of the deleterious pulmonary effects of PM using multi-omics analysis is lacking. In this study, we performed transcriptomic, proteomic, and metabolomic analyses in a mouse model exposed to PM for three months to identify molecular changes in lung tissues. We identified 1690 genes, 326 proteins, and 67 metabolites exhibiting significant differences between PM-challenged and control mice (p < 0.05). Differentially expressed genes and proteins regulated in PM-challenged mice were involved in lipid metabolism and in the immune and inflammatory response processes. Moreover, a comprehensive analysis of transcript, protein, and metabolite datasets revealed that the genes, proteins, and metabolites in the PM-treated group were involved in lysosomal function and lipid metabolism. Specifically, Cathepsin D (Ctsd), Ferritin light chain (Ftl), Lactotransferrin (Ltf), Lipocalin 2 (Lcn2), and Prosaposin (Psap) were major proteins/genes associated with PM-induced pulmonary damage, while two lipid molecules PC (18:1(11Z)/16:0) and PA (16:0/18:1(11Z)) were major metabolites related to PM-induced pulmonary injury. In summary, lipid metabolism might be used as successful precautions and therapeutic targets in PM-induced pulmonary injury to maintain the stability of cellular lysosomal function.

Think Biologically, Act Chemically

A drug is a sophisticated molecule, purposely evolved, resulting from the accumulation of knowledge learned and exploited from simpler molecules over time. Advanced molecules with increased sophistication and capability are derived from simpler, less sophisticated structures with less capabilities. Medicinal chemists do not find, stumble upon, accidentally discover, screen for, or construct drugs. We purposefully evolve molecules through the use of feedback cycles; we emphasize efficiency and simplicity in pursuit of multiproperty homeostasis; and we design and learn from molecular outliers. This Miniperspective illustrates inspirational themes from nature including evolution, feedback cycles, homeostasis, efficiency, and mutation. These biological themes are then exemplified in modern medicinal chemistry practices, such as design-make-test-analyze cycles (feedback), balancing molecular properties (homeostasis), defining the minimum pharmacophore (simplicity, efficiency), understanding molecular outliers (mutants), and the unifying concept of molecular evolution.

Highly Sensitive Two-Photon Lipid Droplet Tracker for In Vivo Screening of Drug Induced Liver Injury

Lipid droplets (LDs) are lipid-abundant organelles found in most cell lines and primarily consist of neutral lipids. They serve as a repository of various lipids and are associated with many cellular metabolic processes, including energy storage, membrane synthesis, and protein homeostasis. LDs are prominent in a variety of diseases related to lipid regulation, including obesity, fatty liver disease, diabetes, and atherosclerosis. To monitor LD dynamics in live samples, we developed a highly selective two-photon fluorescent tracker for LDs (LD1). It exhibited outstanding sensitivity with a remarkable two-photon-action cross section (Φδ_max > 600 GM), photostability, and low cytotoxicity. In human hepatocytes and in vivo mouse liver tissue imaging, LD1 showed very bright fluorescence with high LD selectivity and minimized background signal to evaluate the stages of nonalcoholic fatty liver disease. Interestingly, we demonstrated that the liver sinusoid morphology became narrower with increasing LD size and visualized the dynamics including fusion of the LDs in vivo. Moreover, real-time and dual-color TPM imaging with LD1 and a two-photon lysosome tracker could be a useful predictive screening tool in the drug development process to monitor impending drug-induced liver injury inducing drug candidates.

Mass Spectrometry Imaging Techniques Enabling Visualization of Lipid Isomers in Biological Tissues

This Feature focuses on a review of recent developments in mass spectrometry imaging (MSI) of lipid isomers in biological tissues. The tandem MS techniques utilizing online and offline chemical derivatization procedures, ion activation techniques such as ozone-induced dissociation (OzID), ultraviolet photodissociation (UVPD), or electron-induced dissociation (EID), and other techniques such as coupling of ion mobility with MSI are discussed. The importance of resolving lipid isomers in diseases is highlighted.

Raman and fluorescence imaging of phospholipidosis induced by cationic amphiphilic drugs in endothelial cells

Cationic amphiphilic drugs (CADs) are known from lysosomotropism, drug-induced phospholipidosis (DIPL), activation of autophagy, and decreased cell viability, but the relationship between these events is not clear and little is known about DIPL in the endothelium. In this work, the effects of fluoxetine, amiodarone, clozapine, and risperidone on human microvascular endothelial cells (HMEC-1) were studied using a combined methodology of label-free Raman imaging and fluorescence staining. Raman spectroscopy was applied to characterize biochemical changes in lipid profile and their distribution in the cellular compartments, while fluorescence staining (LysoTracker, LipidTOX, LC3B, and JC-1) was used to analyze lysosome volume expansion, activation of autophagy, lipid accumulation, and mitochondrial membrane depolarization. We demonstrated that fluoxetine, amiodarone, and clozapine, but not risperidone, at non-toxic concentrations induced lipid accumulations in the perinuclear and cytoplasmic regions of endothelial cells. Spectroscopic markers of DIPL included a robust increase in the ratio (lipid/(protein + lipid)), an increase in choline-containing lipid, fatty acids, and the presence of cholesterol esters, while starvation-induced activated autophagy revealed a spectroscopic signature associated with subtle changes in the lipid profile only. Interestingly, lysosomal volume expansion, occurrence of DIPL, and activation of autophagy induced by selected CADs all depended on drug-accumulation in acidic pH of lysosome cellular compartments whereas reduced endothelial viability did not, and was attributed to mitochondrial mechanisms as evidenced by a decreased mitochondrial transmembrane potential. In conclusion, drug-induced phospholipidosis in the endothelium did not reduce endothelial viability per se and can be efficiently assayed by Raman imaging.

Exploring four South African Croton species for potential anti-inflammatory properties: in vitro activity and toxicity risk assessment

ETHNOPHARMACOLOGICAL RELEVANCE

The African Continent harbours approximately 26 Croton species. Many Croton species are used in traditional medicine in southern Africa to treat a variety of ailments including malaria, tuberculosis, microbial infection and inflammation. Considering the high diversity of the genus Croton, the ethnopharmacological information available on southern African species is rather limited. Furthermore, the potential for novel anti-inflammatory drug scaffolds has not previously been investigated.

AIM OF THE STUDY

The aim of the study was to evaluate the potential of four South African Croton species extracts (Croton gratissimus, Croton pseudopulchellus, Croton sylvaticus, and Croton steenkampianus) for anti-inflammatory activity targeting the TLR4 signalling pathway and to assess the potential risk for hepatotoxicity and genotoxicity using an in vitro cellomics approach.

MATERIAL AND METHODS

Leaf extracts of C. gratissimus, C. pseudopulchellus, C. sylvaticus and C. steenkampianus were prepared using methanol and chloroform (1:1, v/v). The anti-inflammatory activity was determined using LPS induced nitric oxide production in RAW 264.7 macrophages, while the hepatotoxicity and genotoxicity was evaluated using multi-parameter end point analysis in C3A and Vero cells, respectively. Mitochondrial membrane potential, mitochondrial mass, oxidative stress, lysosomal content and lipid accumulation were used as markers to assess the risk for hepatotoxicity.

RESULTS

All four species attenuated nitric oxide production with negligible cytotoxicity. However, C. gratissimus yielded the most favorable profile. Cell density was significantly reduced in both C3A and Vero cells with the C. gratissimus extract providing a suitable toxicity profile amenable to further high content analysis. While there was no meaningful effect on mitochondrial dynamics, a strong dose dependent increase in lipid content, paralleled by an expansion of the lysosomal compartment, identifies a potential risk for steatosis. Risk for genotoxicity was investigated using the micronucleus assay which revealed a dose dependent increase in micronuclei formation. Changes in nuclear morphology and cell ploidy further strengthens the associated risk for genotoxicity and suggests the extract from C. gratissimus may function as an aneugen. Collectively, the data demonstrates that although the selected species possess anti-inflammatory components, the risk for possible hepatotoxic and genotoxic side effects may negate their prospect towards further drug development.

Acute and subacute oral toxicity of artemisinin-hydroxychloroquine sulfate tablets in rats

Artemisinin-hydroxychloroquine sulfate tablets (AH) are considered a relatively inexpensive and novel combination therapy for treating all forms of malaria, especially aminoquinoline drugs-resistant strains of P.falciparum. We aim to carry out acute and subacute oral toxicity studies in rats to acquire preclinical data on the safety of AH. Acute toxicity was evaluated in Sprague-Dawley (SD) rats at a single dose of 1980, 2970, 4450, 6670, and 10000 mg/kg. A 14-days subacute toxicity was assessed in SD rats at doses of 0, 146, 219, 328, and 429 mg/kg. The median lethal dose (LD₅₀) of acute oral administration of AH in rats is found to be 3119 mg/kg, and toxic symptoms include decreased spontaneous activity, dyspnea, bristling, soft feces, spasticity, and convulsion. Repeated doses of AH have toxic effects on the nervous system, skin, blood system, liver, kidney, and spleen in rats. The main toxic reactions include epilation, emaciation, mental irritability, decreased body weight gain and food consumption, changes in the hematological and biochemical parameters, especially pathological lesions in the liver, kidney, and spleen. The no-observed-adverse-effect level (NOAEL) and lowest-observed-adverse-effect level (LOAEL) of AH are considered to be 219 mg/kg and 328 mg/kg, respectively.

Citrate-capped gold nanoparticles with a diameter of 14 nm alter the expression of genes associated with stress response, cytoprotection and lipid metabolism in CaCo-2 cells

Advancements in nanotechnology have provided insight into the unique opportunities for the application of nanomaterials such as gold nanoparticles (AuNPs) in medicine due to their remarkable properties, which includes low toxicity, large surface area, and the ease of synthesis and conjugation to other molecules. Therefore, AuNPs are often preferred for bio-applications. Citrate-capped AuNPs (cAuNPs) have been reported to be non-cytotoxic and are used in numerous studies as drug delivery vehicles to treat various diseases. However, the limitations of bioassays often used to assess the toxicity of AuNPs have been well documented. Herein, we investigate the cytotoxicity of 14 nm cAuNPs in the human colorectal adenocarcinoma (Caco-2) cell line. Treatment conditions (i.e. dose and exposure time) that were established to be non-toxic to Caco-2 cells were used to investigate the effect of cAuNPs on the expression of a Qiagen panel of 86 genes involved in cytotoxicity. Out of 86 studied, 23 genes were differentially expressed. Genes involved in oxidative stress and antioxidant response, endoplasmic reticulum (ER) stress and unfolded protein response, heat shock response, and lipid metabolism were more affected than others. While low concentrations of 14 nm cAuNPs was not cytotoxic and did not cause cell death, cells treated with these nanoparticles experienced ER and oxidative stress, resulting in the activation of cytoprotective cellular processes. Additionally, several genes involved in lipid metabolism were also affected. Therefore, 14 nm cAuNPs can safely be used as drug delivery vehicles at low doses.

Drug-Induced Lysosomal Impairment Is Associated with the Release of Extracellular Vesicles Carrying Autophagy Markers

Amiodarone is a cationic amphiphilic drug used as an antiarrhythmic agent. It induces phospholipidosis, i.e., the accumulation of phospholipids within organelles of the endosomal-lysosomal system. Extracellular vesicles (EVs) are membrane-enclosed structures released by any type of cell and retrieved in every fluid of the body. EVs have been initially identified as a system to dispose cell waste, but they are also considered to be an additional manner to transmit intercellular signals. To understand the role of EVs in drug-induced phospholipidosis, we investigated EVs release in amiodarone-treated HEK-293 cells engineered to produce fluorescently labelled EVs. We observed that amiodarone induces the release of a higher number of EVs, mostly of a large/medium size. EVs released upon amiodarone treatment do not display significant morphological changes or altered size distribution, but they show a dose-dependent increase in autophagy associated markers, indicating a higher release of EVs with an autophagosome-like phenotype. Large/medium EVs also show a higher content of phospholipids. Drugs inducing lysosomal impairment such as chloroquine and bafilomycin A1 similarly prompt a higher release of EVs enriched in autophagy markers. This result suggests a mechanism associated with amiodarone-induced lysosomal impairment more than a connection with the accumulation of specific undigested substrates. Moreover, the implementation of the lysosomal function by overexpressing TFEB, a master gene regulator of lysosomal biogenesis, prevents the amiodarone-induced release of EVs, suggesting that this could be a feasible target to attenuate drug-induced abnormalities.

Nonantimicrobial Actions of Macrolides: Overview and Perspectives for Future Development

Macrolides are among the most widely prescribed broad spectrum antibacterials, particularly for respiratory infections. It is now recognized that these drugs, in particular azithromycin, also exert time-dependent immunomodulatory actions that contribute to their therapeutic benefit in both infectious and other chronic inflammatory diseases. Their increased chronic use in airway inflammation and, more recently, of azithromycin in COVID-19, however, has led to a rise in bacterial resistance. An additional crucial aspect of chronic airway inflammation, such as chronic obstructive pulmonary disease, as well as other inflammatory disorders, is the loss of epithelial barrier protection against pathogens and pollutants. In recent years, azithromycin has been shown with time to enhance the barrier properties of airway epithelial cells, an action that makes an important contribution to its therapeutic efficacy. In this article, we review the background and evidence for various immunomodulatory and time-dependent actions of macrolides on inflammatory processes and on the epithelium and highlight novel nonantibacterial macrolides that are being studied for immunomodulatory and barrier-strengthening properties to circumvent the risk of bacterial resistance that occurs with macrolide antibacterials. We also briefly review the clinical effects of macrolides in respiratory and other inflammatory diseases associated with epithelial injury and propose that the beneficial epithelial effects of nonantibacterial azithromycin derivatives in chronic inflammation, even given prophylactically, are likely to gain increasing attention in the future. SIGNIFICANCE STATEMENT: Based on its immunomodulatory properties and ability to enhance the protective role of the lung epithelium against pathogens, azithromycin has proven superior to other macrolides in treating chronic respiratory inflammation. A nonantibiotic azithromycin derivative is likely to offer prophylactic benefits against inflammation and epithelial damage of differing causes while preserving the use of macrolides as antibiotics.

Interaction of Surface Active Drug Promethazine Hydrochloride with Surfactants: Drug Release from Microemulsions

The interaction of surface-active drugs with surfactants, used in the simulation of artificial membranes by direct and reversed micelles, mainly determines the transport of drugs in the body and the complex process of the binding to receptors. Besides, the delivery of drugs into the body via microemulsions has been successfully used to reduce the first-pass metabolism. The structure of mixed reverse microemulsions based on the ionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the cationic surface active drug promethazine hydrochloride (PMT) was studied spectroscopically in the infrared and UV-visible regions, as well as using electrical conductivity and dynamic light scattering. The release profile of PMT from AOT-based microemulsions was studied using cellulose dialysis bags. The introduction of PMT additive into the water pockets of reverse AOT micelles leads to: a) an increase in free water fraction and a decrease in bound water fraction; b) changing the chromatographic retention factors of the model compounds; c) insignificant influence on the values of the binding constant of optical probe o-nitroaniline with the head groups of AOT; d) quenching of water-induced percolation in electrical conductance of reverse AOT microemulsions; e) a slight decrease in the size of water droplets at the same values of the molar ratio of water/surfactant. The release of PMT from the aqueous system obeys Fick’s law of diffusion (n = 0.4852), and the release of PMT from microemulsions is based on non-Fickian or anomalous diffusion.