Mitochondrial dysfunction induced by sertraline, an antidepressant agent

MADD-like pattern of acylcarnitines associated with sertraline use

Multiple acyl-CoA dehydrogenase deficiency (MADD) is a primary mitochondrial dysfunction affecting mitochondrial fatty acid and protein metabolism, caused by biallelic pathogenic variants in ETFA, ETFB, or ETFDH genes. The heterogeneous phenotypes associated with MADD have been classified into three groups: neonatal onset with congenital anomalies (type 1), neonatal onset without congenital anomalies (type 2), and attenuated and/or later onset (type 3). Here, we present two cases with biochemical profiles mimicking late-onset MADD but negative genetic testing, associated with the use of sertraline, a commonly used antidepressant. Case 1 is a 22 yo woman diagnosed with depression and profound fatigue who was referred to the metabolic clinic because of carnitine deficiency and a plasma acylcarnitine profile with a MADD-like pattern. Case 2 is a 61 yo woman with a history of chronic fatigue who was admitted to the emergency department with difficulty swallowing, metabolic acidosis, and mild rhabdomyolysis. Plasma acylcarnitine profile showed a MADD-like pattern. The muscle biopsy revealed lipid droplet accumulation and proliferation of mitochondria with abnormal osmiophilic inclusions, and a biochemical assay of the respiratory chain showed a deficit in complex II activity. In both cases, urine organic acid profile was normal, and genetic tests did not detect variants in the genes involved in MADD. Sertraline was on their list of medications and considering its association with inhibition of mitochondrial function and rhabdomyolysis, the team recommended the discontinuation under medical supervision. In Case 1 after discontinuation, the plasma acylcarnitine test normalized, only to return abnormal when the patient resumed sertraline. In Case 2, after sertraline was discontinued rhabdomyolysis resolved, and the muscle biopsy and biochemical assay of the respiratory chain normalized. Although sertraline is considered a safe drug, these two cases suggest that the use of sertraline may be associated with a potentially reversible form of mitochondrial dysfunction mimicking MADD. Further studies are needed to confirm and estimate the risk of MADD-like presentations with the use of sertraline, as well as identifying additional contributing factors, including genetic factors. Metabolic physicians should consider sertraline use in the differential diagnosis of MADD, particularly when genetic testing is negative.

Advances in drug-induced liver injury research: in vitro models, mechanisms, omics and gene modulation techniques

Drug-induced liver injury (DILI) refers to drug-mediated damage to the structure and function of the liver, ranging from mild elevation of liver enzymes to severe hepatic insufficiency, and in some cases, progressing to liver failure. The mechanisms and clinical symptoms of DILI are diverse due to the varying combination of drugs, making clinical treatment and prevention complex. DILI has significant public health implications and is the primary reason for post-marketing drug withdrawals. The search for reliable preclinical models and validated biomarkers to predict and investigate DILI can contribute to a more comprehensive understanding of adverse effects and drug safety. In this review, we examine the progress of research on DILI, enumerate in vitro models with potential benefits, and highlight cellular molecular perturbations that may serve as biomarkers. Additionally, we discuss omics approaches frequently used to gather comprehensive datasets on molecular events in response to drug exposure. Finally, three commonly used gene modulation techniques are described, highlighting their application in identifying causal relationships in DILI. Altogether, this review provides a thorough overview of ongoing work and approaches in the field of DILI.

Multiple Acyl-Coenzyme A Dehydrogenase Deficiency Is Associated with Sertraline Use - Is There an Acquired Form?

OBJECTIVE

Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is a disorder of fatty acid oxidation and considered an inborn error of metabolism. In recent years, we have diagnosed an increasing number of patients where, despite extensive investigation, no disease-causing mutations have been found. We therefore investigated a cohort of consecutive patients, with the objective to detect possible non-genetic causes.

METHODS

We searched the patient records and the registry of muscle biopsies, for patients with MADD, diagnosed within the past 10 years. The patient records were reviewed regarding symptoms, clinical findings, comorbidities, drugs, diagnostic investigations, and response to treatment. In addition, complementary investigations of muscle tissue were performed.

RESULTS

We identified 9 patients diagnosed with late-onset MADD. All presented with muscle weakness and elevated levels of creatine kinase. A lipid storage myopathy was evident in the muscle biopsies, as was elevated acylcarnitines in blood. Despite thorough genetic investigations, a probable genetic cause was found in only 2 patients. Remarkably, all 7 patients without disease-causing mutations were treated with sertraline. In some cases, a deterioration of symptoms closely followed dose increase, and discontinuation resulted in an improved acylcarnitine profile. All 9 patients responded to riboflavin treatment with normalization of creatine kinase and muscle biopsy findings, and in 8 patients the clinical symptoms clearly improved.

INTERPRETATION

Our findings strongly suggest that sertraline may induce an acquired form of MADD in some patients. Importantly, riboflavin treatment seems to be similarly effective as in genetic MADD, but discontinuation of sertraline is reasonably warranted. ANN NEUROL 2024;96:802-811.

Molecular genetic analysis of candidate genes for glutaric aciduria type II in a cohort of patients from Queensland, Australia

Glutaric aciduria type II (GAII) is a heterogeneous genetic disorder affecting mitochondrial fatty acid, amino acid and choline oxidation. Clinical manifestations vary across the lifespan and onset may occur at any time from the early neonatal period to advanced adulthood. Historically, some patients, in particular those with late onset disease, have experienced significant benefit from riboflavin supplementation. GAII has been considered an autosomal recessive condition caused by pathogenic variants in the gene encoding electron-transfer flavoprotein ubiquinone-oxidoreductase (ETFDH) or in the genes encoding electron-transfer flavoprotein subunits A and B (ETFA and ETFB respectively). Variants in genes involved in riboflavin metabolism have also been reported. However, in some patients, molecular analysis has failed to reveal diagnostic molecular results. In this study, we report the outcome of molecular analysis in 28 Australian patients across the lifespan, 10 paediatric and 18 adult, who had a diagnosis of glutaric aciduria type II based on both clinical and biochemical parameters. Whole genome sequencing was performed on 26 of the patients and two neonatal onset patients had targeted sequencing of candidate genes. The two patients who had targeted sequencing had biallelic pathogenic variants (in ETFA and ETFDH). None of the 26 patients whose whole genome was sequenced had biallelic variants in any of the primary candidate genes. Interestingly, nine of these patients (34.6%) had a monoallelic pathogenic or likely pathogenic variant in a single primary candidate gene and one patient (3.9%) had a monoallelic pathogenic or likely pathogenic variant in two separate genes within the same pathway. The frequencies of the damaging variants within ETFDH and FAD transporter gene SLC25A32 were significantly higher than expected when compared to the corresponding allele frequencies in the general population. The remaining 16 patients (61.5%) had no pathogenic or likely pathogenic variants in the candidate genes. Ten (56%) of the 18 adult patients were taking the selective serotonin reuptake inhibitor antidepressant sertraline, which has been shown to produce a GAII phenotype, and another two adults (11%) were taking a serotonin-norepinephrine reuptake inhibitor antidepressant, venlafaxine or duloxetine, which have a mechanism of action overlapping that of sertraline. Riboflavin deficiency can also mimic both the clinical and biochemical phenotype of GAII. Several patients on these antidepressants showed an initial response to riboflavin but then that response waned. These results suggest that the GAII phenotype can result from a complex interaction between monoallelic variants and the cellular environment. Whole genome or targeted gene panel analysis may not provide a clear molecular diagnosis.

The Effect of Neuropsychiatric Drugs on the Oxidation-Reduction Balance in Therapy

The effectiveness of available neuropsychiatric drugs in the era of an increasing number of patients is not sufficient, and the complexity of neuropsychiatric disease entities that are difficult to diagnose and therapeutically is increasing. Also, discoveries about the pathophysiology of neuropsychiatric diseases are promising, including those initiating a new round of innovations in the role of oxidative stress in the etiology of neuropsychiatric diseases. Oxidative stress is highly related to mental disorders, in the treatment of which the most frequently used are first- and second-generation antipsychotics, mood stabilizers, and antidepressants. Literature reports on the effect of neuropsychiatric drugs on oxidative stress are divergent. They are starting with those proving their protective effect and ending with those confirming disturbances in the oxidation-reduction balance. The presented publication reviews the state of knowledge on the role of oxidative stress in the most frequently used therapies for neuropsychiatric diseases using first- and second-generation antipsychotic drugs, i.e., haloperidol, clozapine, risperidone, olanzapine, quetiapine, or aripiprazole, mood stabilizers: lithium, carbamazepine, valproic acid, oxcarbazepine, and antidepressants: citalopram, sertraline, and venlafaxine, along with a brief pharmacological characteristic, preclinical and clinical studies effects.

Mitochondrial injury induced by triclopyr in the rat liver

The herbicide triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) is already considered an environmental problem due to damage caused by incorrect disposal, leaching, and aerial dispersion, which may pose risks to the environment and human health. Studies have evaluated metabolism, absorption, excretion, and active transport but there is no clear information about its mode of action (MoA) and its cytotoxic action potential remains unknown. In this context, mitochondria have been used to assess the toxicity of xenobiotics, for this reason, to identify the toxic mechanism of triclopyr, hepatic mitochondria from Wistar rats were exposed in vitro to different concentrations of triclopyr (0.5-500 µM). There was neither formation/accumulation of reactive oxygen and nitrogen species, nor lipid peroxidation or changes in the mitochondrial antioxidant system, in addition to proper functioning of oxidative phosphorylation and ATP production. Changes were found in NAD(P)H oxidation, membrane potential dissipation and mitochondrial calcium gradient. These results demonstrate that mitochondria suffer damage related to their bioenergetics and redox status but not to their structure when exposed to concentrations of triclopyr considered higher than those described as found in the environment so far.HighlightsTriclopyr has a low mitochondrial uncoupling potential.The damage caused to the bioenergetics and redox state of the mitochondria is related to concentrations considered higher than those found in the environment.Even at high concentrations, triclopyr was not able to change the structure of the organelle after exposure.Oxidative phosphorylation and ATP production were not impaired after exposure.NAD(P)H oxidation resulted in potential membrane dissipation and mitochondrial calcium gradient dissipation.Triclopyr does not have RONS-forming properties, as well as it does not peroxide membrane lipids, it preserves membrane sulfhydryl groups and maintains the normality of the GSH/GSSG ratio.

Hybrid non-animal modeling: A mechanistic approach to predict chemical hepatotoxicity

Developing mechanistic non-animal testing methods based on the adverse outcome pathway (AOP) framework must incorporate molecular and cellular key events associated with target toxicity. Using data from an in vitro assay and chemical structures, we aimed to create a hybrid model to predict hepatotoxicants. We first curated a reference dataset of 869 compounds for hepatotoxicity modeling. Then, we profiled them against PubChem for existing in vitro toxicity data. Of the 2560 resulting assays, we selected the mitochondrial membrane potential (MMP) assay, a high-throughput screening (HTS) tool that can test chemical disruptors for mitochondrial function. Machine learning was applied to develop quantitative structure-activity relationship (QSAR) models with 2536 compounds tested in the MMP assay for screening new compounds. The MMP assay results, including QSAR model outputs, yielded hepatotoxicity predictions for reference set compounds with a Correct Classification Ratio (CCR) of 0.59. The predictivity improved by including 37 structural alerts (CCR = 0.8). We validated our model by testing 37 reference set compounds in human HepG2 hepatoma cells, and reliably predicting them for hepatotoxicity (CCR = 0.79). This study introduces a novel AOP modeling strategy that combines public HTS data, computational modeling, and experimental testing to predict chemical hepatotoxicity.

Unlocking mitochondrial drug targets: The importance of mitochondrial transport proteins

A disturbed mitochondrial function contributes to the pathology of many common diseases. These organelles are therefore important therapeutic targets. On the contrary, many adverse effects of drugs can be explained by a mitochondrial off-target effect, in particular, due to an interaction with carrier proteins in the inner membrane. Yet this class of transport proteins remains underappreciated and understudied. The aim of this review is to provide a deeper understanding of the role of mitochondrial carriers in health and disease and their significance as drug targets. We present literature-based evidence that mitochondrial carrier proteins are associated with prevalent diseases and emphasize their potential as drug (off-)target sites by summarizing known mitochondrial drug-transporter interactions. Studying these carriers will enhance our knowledge of mitochondrial drug on- and off-targets and provide opportunities to further improve the efficacy and safety of drugs.

Catalyst-free anti-Markovnikov hydroamination and hydrothiolation of vinyl heteroarenes in aqueous medium: an improved process towards centhaquine

Catalyst-free hydroamination and hydrothiolation of alkenes have been achieved in an aqueous medium. The anti-Markovnikov addition works efficiently in suspended water at room temperature and allows straightforward access to centhaquine, a drug used for the management of hypovolemic shocks in critically ill patients, and its derivatives. Various primary and secondary amines, thiols, and hydrazides were successfully reacted with a number of heteroaryl/aryl-alkenes. The scalability of the process has been demonstrated by synthesizing centhaquine at a 19.65 g scale. A comparative analysis of the present process with previous approaches has been provided on the basis of green chemistry metrics.

Mitochondrial dynamics disruption: Unraveling Dinotefuran's impact on cardiotoxicity

Exposure to pesticides has been associated with several cardiovascular complications in animal models. Neonicotinoids are now the most widely used insecticide globally, while the impact of neonicotinoids on cardiovascular function and the role of mitochondrial dynamics in neonicotinoids-induced cardiotoxicity is unclear. In the present study, Xenopus laevis tadpoles were exposed to environmental related concentrations (0, 5, and 50 μg/L) of typical neonicotinoid dinotefuran, with two enantiomers, for 21 days. We evaluated the changes in heart rate and cardiomyocyte apoptosis in exposed tadpoles. Then, we performed the transcriptome, metabolomics, transmission electron microscopy (TEM), and protein immunoblot to investigate the potential adverse impact of two enantiomers of dinotefuran on cardiotoxicity associated with mitochondrial dynamics. We observed changes in heart rate and increased cardiomyocyte apoptosis in exposed tadpoles, indicating that dinotefuran had a cardiotoxic effect. We further found that the cardiac contractile function pathway was significantly enriched, while the glucose metabolism-related pathways were also disturbed significantly. TEM observation revealed that the mitochondrial morphology of cardiomyocytes in exposed tadpoles was swollen, and mitophagy was increased. Mitochondria fusion was excessively manifested in the enhanced mitochondrial fusion protein. The mitochondrial respiratory chain was also disturbed, which led to an increase in ROS production and a decrease in ATP content. Therefore, our results suggested that dinotefuran exposure can induce cardiac disease associated mitochondrial disorders by interfering with the functionality and dynamics of mitochondria. In addition, both two enantiomers of dinotefuran have certain toxicity to tadpole cardiomyocytes, while R-dinotefuran exhibited higher toxicity than S-enantiomer, which may be attributed to disparities in the activation capacities of the respiratory chain.

Antidepressant Sertraline Hydrochloride Inhibits the Growth of HER2+ AU565 Breast Cancer Cell Line through Induction of Apoptosis and Cell Cycle Arrest

BACKGROUND

Drug repurposing in oncology promises benefits to many patients through its ability to provide novel, and fast-tracked treatments. Previous studies have demonstrated that depression may influence tumor progression. Anti-proliferative activity of certain antidepressants, mainly selective serotonin reuptake inhibitors (SSRIs), are reported in the literature.

OBJECTIVE

This study was conducted to repurpose selective serotonin reuptake inhibitors (SSRIs) for the treatment of breast cancers, and it merits further validation and research.

METHODS

Changes in cell morphology were studied using DAPI staining, while the Annexin V/PI method was employed for apoptotic analysis. The expression of specific genes involved in cancer progression was also analyzed via RT-PCR. Caspase-3 activation was measured through fluorometric assay.

RESULTS

We have identified that sertraline hydrochloride significantly inhibited the growth of breast cancer cell in vitro. Preliminary mechanistic studies demonstrated that the cytotoxicity of sertraline hydrochloride was possibly through the induction of apoptosis, as inferred from enhanced nuclear fragmentation, flow cytometric data, and caspase-3/7 activation. Gene expression analysis also showed an increased expression of pro-apoptotic Bax, and a slight decrease in oncogene c-myc in the presence of sertraline hydrochloride.

CONCLUSION

In conclusion, our study suggest that sertraline hydrochloride, an antidepressant drug, can potentially be used for the treatment of breast cancer.

Sertraline associated with gold nanoparticles reduce cellular toxicity and induce sex-specific responses in behavior and neuroinflammation biomarkers in a mouse model of anxiety

This study aimed to evaluate the effects of sertraline associated with gold nanoparticles (AuNPs) in vitro cell viability and in vivo behavior and inflammatory biomarkers in a mouse model of anxiety. Sertraline associated with AuNPs were synthesized and characterized. For the in vitro study, NIH3T3 and HT-22 cells were treated with different doses of sertraline, AuNPs, and sertraline + AuNPs and their viability was evaluated using the MTT assay. For the in vivo study, pregnant Swiss mice were administered a single dose of lipopolysaccharide (LPS) on the ninth day of gestation. The female and male offspring were divided into five treatment groups on PND 60 and administered chronic treatment for 28 days. The animals were subjected to behavioral testing and were subsequently euthanized. Their brains were collected and analyzed for inflammatory biomarkers. Sertraline associated with AuNPs exhibited significant changes in surface characteristics and increased diameters. Different doses of sertraline + AuNPs showed higher cell viability in NIH3T3 and HT-22 cells compared with sertraline alone. The offspring of LPS-treated dams exhibited anxiety-like behavior and neuroinflammatory biomarker changes during adulthood, which were ameliorated via sertraline + AuNPs treatment. The treatment response was sex-dependent and brain region-specific. These results suggest that AuNPs, which demonstrate potential to bind to other molecules, low toxicity, and reduced inflammation, can be synergistically used with sertraline to improve drug efficacy and safety by decreasing neuroinflammation and sertraline toxicity.

Metabolic impact of genetic and chemical ADP/ATP carrier inhibition in renal proximal tubule epithelial cells

Mitochondrial dysfunction is pivotal in drug-induced acute kidney injury (AKI), but the underlying mechanisms remain largely unknown. Transport proteins embedded in the mitochondrial inner membrane form a significant class of potential drug off-targets. So far, most transporter-drug interactions have been reported for the mitochondrial ADP/ATP carrier (AAC). Since it remains unknown to what extent AAC contributes to drug-induced mitochondrial dysfunction in AKI, we here aimed to better understand the functional role of AAC in the energy metabolism of human renal proximal tubular cells. To this end, CRISPR/Cas9 technology was applied to generate AAC3-/- human conditionally immortalized renal proximal tubule epithelial cells. This AAC3-/- cell model was characterized with respect to mitochondrial function and morphology. To explore whether this model could provide first insights into (mitochondrial) adverse drug effects with suspicion towards AAC-mediated mechanisms, wild-type and knockout cells were exposed to established AAC inhibitors, after which cellular metabolic activity and mitochondrial respiratory capacity were measured. Two AAC3-/- clones showed a significant reduction in ADP import and ATP export rates and mitochondrial mass, without influencing overall morphology. AAC3-/- clones exhibited reduced ATP production, oxygen consumption rates and metabolic spare capacity was particularly affected, mainly in conditions with galactose as carbon source. Chemical AAC inhibition was stronger compared to genetic inhibition in AAC3-/-, suggesting functional compensation by remaining AAC isoforms in our knockout model. In conclusion, our results indicate that ciPTEC-OAT1 cells have a predominantly oxidative phenotype that was not additionally activated by switching energy source. Genetic inhibition of AAC3 particularly impacted mitochondrial spare capacity, without affecting mitochondrial morphology, suggesting an important role for AAC in maintaining the metabolic spare respiration.

Different Effects of SSRIs, Bupropion, and Trazodone on Mitochondrial Functions and Monoamine Oxidase Isoform Activity

Mitochondrial dysfunction is involved in the pathophysiology of psychiatric and neurodegenerative disorders and can be used as a modulator and/or predictor of treatment responsiveness. Understanding the mitochondrial effects of antidepressants is important to connect mitochondria with their therapeutic and/or adverse effects. Pig brain-isolated mitochondria were used to evaluate antidepressant-induced changes in the activity of electron transport chain (ETC) complexes, monoamine oxidase (MAO), mitochondrial respiratory rate, and ATP. Bupropion, escitalopram, fluvoxamine, sertraline, paroxetine, and trazodone were tested. All tested antidepressants showed significant inhibition of complex I and IV activities at high concentrations (50 and 100 µmol/L); complex II + III activity was reduced by all antidepressants except bupropion. Complex I-linked respiration was reduced by escitalopram >> trazodone >> sertraline. Complex II-linked respiration was reduced only by bupropion. Significant positive correlations were confirmed between complex I-linked respiration and the activities of individual ETC complexes. MAO activity was inhibited by all tested antidepressants, with SSRIs causing a greater effect than trazodone and bupropion. The results indicate a probable association between the adverse effects of high doses of antidepressants and drug-induced changes in the activity of ETC complexes and the respiratory rate of mitochondria. In contrast, MAO inhibition could be linked to the antidepressant, procognitive, and neuroprotective effects of the tested antidepressants.

Silymarin attenuates escitalopram (cipralex) induced pancreatic injury in adult male albino rats: a biochemical, histological, and immunohistochemical approach

Depression is a prevalent global problem since ages, predominately treated with SSRI. Cipralex, is an antidepressant of the SSRIs class used as a remedy for mood, depression and anxiety. Silymarin (SIL), a natural free radical scavenging, has an antioxidant and anti-inflammatory properties. This hypothesis evaluates, for the first time, the role of cipralex on the structure of the endocrine and exocrine components of the pancreas and assess the beneficial effects of SIL on these changes. Forty-five rats were divided into control, cipralex, and cipralex plus SIL groups. During sacrifice, all rats and pancreases were weighed and the ratio of pancreatic weight (PW) to rat weight (RW) was calculated, blood samples were collected to estimate fasting glucose, insulin and amylase levels, the specimens were prepared for histological, immunohistochemical (inducible nitric oxide synthase [iNOS], tumour necrosis factor-alpha [TNF-α], caspase 3, proliferating cell nuclear antigen [PCNA], and anti-insulin antibody), and morphometrical studies. Cipralex group exhibited marked destruction of the pancreatic architecture of the exocrine and endocrine parts, with a dense collagen fiber deposition. Also, there is highly significant decrease (P<0.001) of PW/RT ratio, insulin, and amylase levels, the number and diameter of islets of Langerhans, the number of PCNA positive immunoreactive cells, and the number of insulin positive β-cells. Furthermore, a highly significant increase of glucose level, iNOS, TNF-α, and caspase-3 positive immunoreactive cells in the islets of Langerhans and acinar cells were observed. SIL improves the pancreatic histological architecture, weight loss, biochemical, and immunohistochemical analyses. Administering SIL is advantageous in managing cipralex induced pancreatic injury via its anti-inflammatory, antioxidant, and anti-apoptotic qualities.

Comparative evaluation of natural neuroprotectives and their combinations on chronic immobilization stress-induced depression in experimental mice

The present study evaluates the potential of neuroprotective phytochemicals-rutin (R), resveratrol (Res), 17β-estradiol (17β-E2), and their different combinations against chronic immobilization stress (CIS)-induced depression-like behaviour in male albino mice. Here, the mice were exposed to stress via immobilization of their four limbs under a restrainer for 6 h daily until 7 days of the induction after 30 min of respective drug treatment in different mice groups. The result found the protective effect of these phytoconstituents and their combinations against CIS-induced depression due to their ability to suppress oxidative stress, restore mitochondria, HPA-axis modulation, neurotransmitter level, stress hormones, and inflammatory markers. Also, the combination drug regimens of these phytoconstituents showed synergistic results in managing the physiological and biochemical features of depression. Thus, these neuroprotective could be utilized well in combination to manage depression-like symptoms during episodic stress. Furthermore, such results could be well justified when administered in polyherbal formulation with these neuroprotective as major components. In addition, an advanced study can be designed at the molecular and epigenetics level using a formulation based on these neuroprotective.

Drug-induced mitochondrial toxicity: Risks of developing glucose handling impairments

Mitochondrial impairment has been associated with the development of insulin resistance, the hallmark of type 2 diabetes mellitus (T2DM). However, the relationship between mitochondrial impairment and insulin resistance is not fully elucidated due to insufficient evidence to support the hypothesis. Insulin resistance and insulin deficiency are both characterised by excessive production of reactive oxygen species and mitochondrial coupling. Compelling evidence states that improving the function of the mitochondria may provide a positive therapeutic tool for improving insulin sensitivity. There has been a rapid increase in reports of the toxic effects of drugs and pollutants on the mitochondria in recent decades, interestingly correlating with an increase in insulin resistance prevalence. A variety of drug classes have been reported to potentially induce toxicity in the mitochondria leading to skeletal muscle, liver, central nervous system, and kidney injury. With the increase in diabetes prevalence and mitochondrial toxicity, it is therefore imperative to understand how mitochondrial toxicological agents can potentially compromise insulin sensitivity. This review article aims to explore and summarise the correlation between potential mitochondrial dysfunction caused by selected pharmacological agents and its effect on insulin signalling and glucose handling. Additionally, this review highlights the necessity for further studies aimed to understand drug-induced mitochondrial toxicity and the development of insulin resistance.

Garlic and allopurinol alleviate the apoptotic pathway in rats' brain following exposure to fipronil insecticide

Fipronil can cause oxidative tissue damage and apoptosis. Our goal is to evaluate the antiapoptotic impact of garlic or allopurinol against fipronil neurotoxicity. Thirty-six mature male albino rats were separated into control, garlic aqueous extract (500 mg/kg), allopurinol (150 mg/L in their drinking water), fipronil (13.277 mg/kg), garlic+fipronil, and allopurinol+fipronil. Our results revealed that fipronil induced a significant increase in brain malondialdehyde, protein carbonyl levels as well as enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione peroxidase, and xanthine oxidase), but glutathione-S-transferase recorded a significant decrease as compared to the control. In addition, fipronil significantly up-regulated the brain pro-apoptotic (Bax) and caspase -3 mRNA gene expression and induced DNA fragmentation but caused down-regulation in anti-apoptotic (Bcl-2) mRNA genes expression. Interestingly, co-administration with garlic or allopurinol improved the lipid peroxidation, antioxidant disturbance, and apoptosis induced by fipronil in the brain tissues. In conclusion, garlic or allopurinol reduced fipronil-induced apoptosis and reduced oxidative tissue damage, most likely through enhancing the tissue antioxidant defense system.

Alterations of mitochondrial dynamics in serotonin transporter knockout rats: A possible role in the fear extinction recall mechanisms

Stress-related mental disorders encompass a plethora of pathologies that share the exposure to a negative environment as trigger for their development. The vulnerability to the effects of a negative environment is not equal to all but differs between individuals based on the genetic background makeup. Here, to study the molecular mechanisms potentially underlying increased threat anticipation, we employed an animal model showing this symptom (5-HTT knockout rats) which we exposed to Pavlovian fear conditioning (FC). We investigated the role of mitochondria, taking advantage of the recent evidence showing that the dynamic of these organelles is dysregulated after stress exposure. Behavioral experiments revealed that, during the second day of extinction of the FC paradigm, 5-HTT knockout (5-HTT-/-) animals showed a lack of fear extinction recall. From a mechanistic standpoint, we carried out our molecular analyses on the amygdala and prefrontal cortex, given their role in the management of the fear response due to their tight connection. We demonstrated that mitochondrial dynamics are impaired in the amygdala and prefrontal cortex of 5-HTT-/- rats. The dissection of the potential contributing factors revealed a critical role in the mechanisms regulating fission and fusion that are dysregulated in transgenic animals. Furthermore, mitochondrial oxidative phosphorylation, mitochondrial biogenesis, and the production of antioxidant enzymes were altered in these brain regions in 5-HTT-/- rats. In summary, our data suggest that increased extracellular 5-HT levels cause an unbalance of mitochondrial functionality that could contribute to the reduced extinction recall of 5-HTT-/- rats, pointing out the role of mitochondrial dynamics in the etiology of psychiatric disorders. Our findings, also, provide some interesting insights into the targeted development of drugs to treat such disorders.

Assessing Drug-Induced Mitochondrial Toxicity in Cardiomyocytes: Implications for Preclinical Cardiac Safety Evaluation

Drug-induced cardiotoxicity not only leads to the attrition of drugs during development, but also contributes to the high morbidity and mortality rates of cardiovascular diseases. Comprehensive testing for proarrhythmic risks of drugs has been applied in preclinical cardiac safety assessment for over 15 years. However, other mechanisms of cardiac toxicity have not received such attention. Of them, mitochondrial impairment is a common form of cardiotoxicity and is known to account for over half of cardiovascular adverse-event-related black box warnings imposed by the U.S. Food and Drug Administration. Although it has been studied in great depth, mitochondrial toxicity assessment has not yet been incorporated into routine safety tests for cardiotoxicity at the preclinical stage. This review discusses the main characteristics of mitochondria in cardiomyocytes, drug-induced mitochondrial toxicities, and high-throughput screening strategies for cardiomyocytes, as well as their proposed integration into preclinical safety pharmacology. We emphasize the advantages of using adult human primary cardiomyocytes for the evaluation of mitochondrial morphology and function, and the need for a novel cardiac safety testing platform integrating mitochondrial toxicity and proarrhythmic risk assessments in cardiac safety evaluation.

Antidepressants induce toxicity in human placental BeWo cells

Selective serotonin reuptake inhibitors (SSRIs), serotonin and noradrenaline reuptake inhibitors (SNRIs), and noradrenergic and specific serotonergic antidepressants (NaSSAs) are broadly used for the treatment of depression. Depression is one of the most common psychiatric disorders in pregnant women and SSRIs are commonly prescribed for depression during pregnancy. The placenta regulates the transport of nutrients and oxygen between the maternal and fetal circulation, and is essential for the survival and growth of the fetus. The present study investigated the effects of antidepressants on human placental BeWo cells. BeWo cell viability was significantly decreased following exposure to sertraline (SSRI), paroxetine (SSRI), fluvoxamine (SSRI), and duloxetine (SNRI), whereas escitalopram (SSRI), venlafaxine (SNRI), and mirtazapine (NaSSA) showed little or no effects. Extracellular lactate dehydrogenase activity was increased by sertraline, paroxetine, fluvoxamine, and duloxetine, indicating toxicity to the cells. Sertraline increased the production of cellular reactive oxygen species (ROS) and decreased the mitochondrial membrane potential. Sertraline decreased the cellular ATP content in a time and concentration-dependent manner. Caspase-3/7 activity and apoptotic cells, detected using the phosphatidylserine-specific fluorescent probe Apotracker Green, were increased by sertraline. Our findings suggest that antidepressants, such as sertraline, paroxetine, fluvoxamine, and duloxetine, induce toxicity in human placental BeWo cells. Sertraline may induce ROS-dependent apoptosis in human placental cells. These results are useful for further studies to determine the optimal dosage of antidepressants for pregnant women.

Prescription Drugs and Mitochondrial Metabolism

Mitochondria are central to the physiology and survival of nearly all eukaryotic cells and house diverse metabolic processes including oxidative phosphorylation, reactive oxygen species buffering, metabolite synthesis/exchange, and Ca2+ sequestration. Mitochondria are phenotypically heterogeneous and this variation is essential to the complexity of physiological function among cells, tissues, and organ systems. As a consequence of mitochondrial integration with so many physiological processes, small molecules that modulate mitochondrial metabolism induce complex systemic effects. In the case of many common prescribed drugs, these interactions may contribute to drug therapeutic mechanisms, induce adverse drug reactions, or both. The purpose of this article is to review historical and recent advances in the understanding of the effects of prescription drugs on mitochondrial metabolism. Specific 'modes' of xenobiotic-mitochondria interactions are discussed to provide a set of qualitative models that aid in conceptualizing how the mitochondrial energy transduction system may be affected. Findings of recent in vitro high-throughput screening studies are reviewed, and a few candidate drug classes are chosen for additional brief discussion (i.e. antihyperglycemics, antidepressants, antibiotics, and antihyperlipidemics). Finally, recent improvements in pharmacokinetic models that aid in quantifying systemic effects of drug-mitochondria interactions are briefly considered.

Complex Effects of Sertraline and Citalopram on In Vitro Murine Breast Cancer Proliferation and on In Vivo Progression and Anxiety Level

Some selective serotonin reuptake inhibitors (SSRIs), primarily sertraline, demonstrate anti-proliferative activity in malignant cell-lines and in xenografted mouse models of colorectal tumor. There is, however, a paucity of comparative studies on the anti-tumor effects of SSRIs. We compared the in vitro and in vivo effects of sertraline and citalopram on murine 4T1 breast cancer. Grafted mice were used to determine the rate of tumor growth and survival as well as the impact of stress and antidepressant treatment on tumor progression and mortality and on pro-inflammatory cytokines. Sertraline, in the micromolar range, but not citalopram, induced a significant in vitro concentration-dependent inhibition of murine 4T1 cell proliferation and splenocyte viability. In contrast, sertraline (10 mg/kg/d), enhanced in vivo tumor growth. Contrary to the study's hypothesis, chronic mild stress did not modify tumor growth in grafted mice. The in vitro effects of sertraline on tumor growth seem to be the opposite of its in vivo effects. The impact of sertraline treatment on humans with breast cancer should be further investigated.

Characterization of drug-induced human mitochondrial ADP/ATP carrier inhibition

An increasing number of commonly prescribed drugs are known to interfere with mitochondrial function, causing cellular toxicity, but the underlying mechanisms are largely unknown. Although often not considered, mitochondrial transport proteins form a significant class of potential mitochondrial off-targets. So far, most drug interactions have been reported for the mitochondrial ADP/ATP carrier (AAC), which exchanges cytosolic ADP for mitochondrial ATP. Here, we show inhibition of cellular respiratory capacity by only a subset of the 18 published AAC inhibitors, which questions whether all compound do indeed inhibit such a central metabolic process. This could be explained by the lack of a simple, direct model system to evaluate and compare drug-induced AAC inhibition.

Methods: For its development, we have expressed and purified human AAC1 (hAAC1) and applied two approaches. In the first, thermostability shift assays were carried out to investigate the binding of these compounds to human AAC1. In the second, the effect of these compounds on transport was assessed in proteoliposomes with reconstituted human AAC1, enabling characterization of their inhibition kinetics.

Results: Of the proposed inhibitors, chebulinic acid, CD-437 and suramin are the most potent with IC₅₀-values in the low micromolar range, whereas another six are effective at a concentration of 100 μM. Remarkably, half of all previously published AAC inhibitors do not show significant inhibition in our assays, indicating that they are false positives. Finally, we show that inhibitor strength correlates with a negatively charged surface area of the inhibitor, matching the positively charged surface of the substrate binding site.

Conclusion: Consequently, we have provided a straightforward model system to investigate AAC inhibition and have gained new insights into the chemical compound features important for inhibition. Better evaluation methods of drug-induced inhibition of mitochondrial transport proteins will contribute to the development of drugs with an enhanced safety profile.

Environmentally relevant concentrations of carbamazepine induced lipid metabolism disorder of Chinese rare minnow (Gobiocypris rarus) in a gender-specific pattern

Carbamazepine (CBZ), an anticonvulsant and mood stabilizer, is ubiquitous distributed in aquatic environment. Though the toxicity and endocrine disrupting effect of CBZ on non-target organisms have been studied, its lipotoxity are scarcely known. To assess the lipotoxicity of CBZ, 2-month-old Chinese rare minnow were exposed to 0, 1, 10, and 100 μg/L CBZ for 90 d. Obvious dyslipidemia was observed after 30 d and 90 d exposure, whereas overt hyperlipidemia was observed in males at 100 μg/L treatments. Severe lipid droplet accumulation in livers was observed at 10 and 100 μg/L treatments for 30 d and in females, whereas those was observed at all treatments in males. In addition, serious mitochondria damage was observed in males at 100 μg/L treatments. After 90 d exposure, the enzyme activities of FAS and ACCα were significantly increased at 10 and 100 μg/L treatments, whereas HMGCR were markedly increased at 100 μg/L treatments (p < 0.05). However, ACCβ were markedly decreased in females at 10 and 100 μg/L treatments and in males at all treatments (p < 0.05). The transcription levels of fasn, accα, hmgcrα, fdft1, idi1, plin1, plin2, caveolin1, and caveolin2 were significantly increased at 100 μg/L treatments (p < 0.05). Moreover, the body weight was obviously increased at 10 and 100 μg/L treatments in males (p < 0.05). Our results confirmed that environmental relevant concentrations CBZ induced lipid metabolism disorder and mitochondria damage of Chinese rare minnow in a gender-specific pattern, which provided a new insight into the lipotoxicity mechanism of CBZ.

Investigating dihydroorotate dehydrogenase inhibitor mediated mitochondrial dysfunction in hepatic in vitro models

Inhibition of dihydroorotate dehydrogenase (DHODH), the rate-limiting enzymatic step in de novo pyrimidine synthesis, has broad immunosuppressive effects in vivo and shows promise as a therapeutic target for the treatment of malignancies, viral infections and auto-immune diseases. Whilst there are numerous DHODH inhibitors under development, leflunomide and teriflunomide are the only FDA approved compounds on the market, each of which have been issued with black-box warnings for hepatotoxicity. Mitochondrial dysfunction is a putative mechanism by which teriflunomide and leflunomide elicit their hepatotoxic effects, however it is as yet unclear whether this is shared by other nascent DHODH inhibitors. The present study aimed to evaluate the propensity for DHODH inhibitors to mediate mitochondrial dysfunction in two hepatic in vitro models. Initial comparisons of cytotoxicity and ATP content in HepaRG® cells primed for oxidative metabolism, in tandem with mechanistic evaluations by extracellular flux analysis identified multifactorial toxicity and moderate indications of respiratory chain dysfunction or uncoupling. Further investigations using HepG2 cells, a hepatic line with limited capability for phase I xenobiotic metabolism, identified leflunomide and brequinar as positive mitochondrial toxicants. Taken together, biotransformation of some DHODH inhibitor species may play a role in mediating or masking hepatic mitochondrial liabilities.

Antidepressants- and antipsychotics-induced hepatotoxicity

Drug-induced liver injury (DILI) is a serious health burden. It has diverse clinical presentations that can escalate to acute liver failure. The worldwide increase in the use of psychotropic drugs, their long-term use on a daily basis, common comorbidities of psychiatric and metabolic disorders, and polypharmacy in psychiatric patients increase the incidence of psychotropics-induced DILI. During the last 2 decades, hepatotoxicity of various antidepressants (ADs) and antipsychotics (APs) received much attention. Comprehensive review and discussion of accumulated literature data concerning this issue are performed in this study, as hepatotoxic effects of most commonly prescribed ADs and APs are classified, described, and discussed. The review focuses on ADs and APs characterized by the risk of causing liver damage and highlights the ones found to cause life-threatening or severe DILI cases. In parallel, an overview of hepatic oxidative stress, inflammation, and steatosis underlying DILI is provided, followed by extensive review and discussion of the pathophysiology of AD- and AP-induced DILI revealed in case reports, and animal and in vitro studies. The consequences of some ADs and APs ability to affect drug-metabolizing enzymes and therefore provoke drug–drug interactions are also addressed. Continuous collecting of data on drugs, mechanisms, and risk factors for DILI, as well as critical data reviewing, is crucial for easier DILI diagnosis and more efficient risk assessment of AD- and AP-induced DILI. Higher awareness of ADs and APs hepatotoxicity is the prerequisite for their safe use and optimal dosing.

Comparative transcriptomics implicate mitochondrial and neurodevelopmental impairments in larval zebrafish (Danio rerio) exposed to two selective serotonin reuptake inhibitors (SSRIs)

Pharmaceuticals and personal care products are emerging contaminants that are increasingly detected in the environment worldwide. Certain classes of pharmaceuticals, such as selective serotonin reuptake inhibitors (SSRIs), are a major environmental concern due to their widespread use and the fact that these compounds are designed to have biological effects at low doses. A complication in predicting toxic effects of SSRIs in nontarget organisms is that their mechanism of action is not fully understood. To better understand the potential toxic effects of SSRIs, we employed an ultra-low input RNA-sequencing method to identify potential pathways that are affected by early exposure to two SSRIs (fluoxetine and paroxetine). We exposed wildtype zebrafish (Danio rerio) embryos to 100 μg/L of either fluoxetine or paroxetine for 6 days before extracting and sequencing mRNA from individual larval brains. Differential gene expression analysis identified 1550 genes that were significantly affected by SSRI exposure with a core set of 138 genes altered by both SSRIs. Weighted gene co-expression network analysis identified 7 modules of genes whose expression patterns were significantly correlated with SSRI exposure. Functional enrichment analysis of differentially expressed genes as well as network module genes repeatedly identified various terms associated with mitochondrial and neuronal structures, mitochondrial respiration, and neurodevelopmental processes. The enrichment of these terms indicates that toxic effects of SSRI exposure are likely caused by mitochondrial dysfunction and subsequent neurodevelopmental effects. To our knowledge, this is the first effort to study the tissue-specific transcriptomic effects of SSRIs in developing zebrafish, providing specific, high resolution molecular data regarding the sublethal effects of SSRI exposure.

Diazinon impairs bioenergetics and induces membrane permeability transition on mitochondria isolated from rat liver

Diazinon (DZN) is a broad-spectrum insecticide extensively used to control pests in crops and animals. Several investigators demonstrated that DZN produced tissue toxicity especially to the liver. In addition, the mitochondrion was implicated in DZN-induced toxicity, but the precise role of this organelle remains to be determined. The aim of this study was thus to examine the effects of DZN (50 to 150 μM) on the bioenergetics and mitochondrial permeability transition (MPT) associated processes in isolated rat liver mitochondria. DZN inhibited state-3 respiration in mitochondria energized with glutamate plus malate, substrates of complex I, and succinate, substrate of complex II of the respiratory chain and decreased the mitochondrial membrane potential resulting in inhibition of ATP synthesis. MPT was estimated by the extent of mitochondrial swelling, in the presence of 10 µM Ca²⁺. DZN elicited MPT in a concentration-dependent manner, via a mechanism sensitive to cyclosporine A, EGTA, ruthenium red and N-ethylmaleimide, which was associated with mitochondrial Ca²⁺ efflux and cytochrome c release. DZN did not result in hydrogen peroxide accumulation or glutathione oxidation, but this insecticide oxidized endogenous NAD(P)H and protein thiol groups. Data suggest the involvement of mitochondria, via apoptosis, in the hepatic cytotoxicity attributed to DZN.

Mitochondrial dysfunction and apoptosis underlie the hepatotoxicity of perhexiline

Perhexiline is an anti-anginal drug developed in the late 1960s. Despite its therapeutic success, it caused severe hepatoxicity in selective patients, which resulted in its withdrawal from the market. In the current study we explored the molecular mechanisms underlying the cytotoxicity of perhexiline. In primary human hepatocytes, HepaRG cells, and HepG2 cells, perhexiline induced cell death in a concentration- and time-dependent manner. Perhexiline treatment also caused a significant increase in caspase 3/7 activity at 2 h and 4 h. Pretreatment with specific caspase inhibitors suggested that both intrinsic and extrinsic apoptotic pathways contributed to perhexiline-induced cytotoxicity, which was confirmed by increased expression of TNF-α, cleavage of caspase 3 and 9 upon perhexiline treatment. Moreover, perhexiline caused mitochondrial dysfunction, demonstrated by the classic glucose-galactose assay at 4 h and 24 h. Results from JC-1 staining suggested perhexiline caused loss of mitochondrial potential. Blocking mitochondrial permeability transition pore using inhibitor bongkrekic acid attenuated the cytotoxicity of perhexiline. Western blotting analysis also showed decreased expression level of pro-survival proteins Bcl-2 and Mcl-1, and increased expression of pro-apoptotic protein Bad. Direct measurement of the activity of individual components of the mitochondrial respiratory complex demonstrated that perhexiline strongly inhibited Complex IV and Complex V and moderately inhibited Complex II and Complex II + III. Overall, our data demonstrated that both mitochondrial dysfunction and apoptosis underlies perhexiline-induced hepatotoxicity.

The role of hepatic cytochrome P450s in the cytotoxicity of sertraline

Sertraline, an antidepressant, is commonly used to manage mental health symptoms related to depression, anxiety disorders, and obsessive-compulsive disorder. The use of sertraline has been associated with rare but severe hepatotoxicity. Previous research demonstrated that mitochondrial dysfunction, apoptosis, and endoplasmic reticulum stress were involved in sertraline-associated cytotoxicity. In this study, we reported that after a 24-h treatment in HepG2 cells, sertraline caused cytotoxicity, suppressed topoisomerase I and IIα, and damaged DNA in a concentration-dependent manner. We also investigated the role of cytochrome P450 (CYP)-mediated metabolism in sertraline-induced toxicity using our previously established HepG2 cell lines individually expressing 14 CYPs (1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4, 3A5, and 3A7). We demonstrated that CYP2D6, 2C19, 2B6, and 2C9 metabolize sertraline, and sertraline-induced cytotoxicity was significantly decreased in the cells expressing these CYPs. Western blot analysis demonstrated that the induction of ɣH2A.X (a hallmark of DNA damage) and topoisomerase inhibition were partially reversed in CYP2D6-, 2C19-, 2B6-, and 2C9-overexpressing HepG2 cells. These data indicate that DNA damage and topoisomerase inhibition are involved in sertraline-induced cytotoxicity and that CYPs-mediated metabolism plays a role in decreasing the toxicity of sertraline.

Synergistic antioxidant effects of resveratrol and curcumin against fipronil-triggered oxidative damage in male albino rats

Fipronil (FPN), a phenylpyrazole insecticide, has been receiving increased attention owing to its toxicity, which is largely mediated through its effects on antioxidant systems. The present study was undertaken to assess the effects of resveratrol (RSV) and curcumin (CUR) on oxidative damage induced by FPN. Forty mature male Wistar rats were randomized into five groups (n = 8 per group): the first group was the control; the second was administered FPN (10 mg/kg); and the third, fourth, and fifth were co-treated with RSV (10 mg/kg), CUR (200 mg/kg), and their combination, respectively, 2 h prior to FPN administration. All animals were dosed via oral gavage for 4 weeks. FPN significantly (p < 0.05) elevated the sera of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), γ-glutamyl transferase (GGT), urea, creatinine, and cholesterol levels, whereas serum total protein, albumin, and triglyceride levels were significantly (p < 0.05) decreased, compared to those of the control group. Reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were decreased (p < 0.05) in the FPN-treated group compared to those in the control group; however, malondialdehyde (MDA) and nitric oxide (NO) levels were markedly increased (p < 0.05) in the hepatic, renal, and brain tissues. Co-treatment with RSV or CUR alleviated (p ˂ 0.05) the increased lipid peroxidation and changes in enzymatic/nonenzymatic antioxidants induced by FPN; all these variables mostly returned to normal levels with the combined of RSV and CUR treatment. In conclusion, RSV and/or CUR relieved and synergistically reversed the FPN-induced tissue oxidative injury, probably by improving the antioxidant defenses via their free radical scavenging and antioxidant characteristics.

Metabolomic Investigations of the Temporal Effects of Exposure to Pharmaceuticals and Personal Care Products and Their Mixture in the Eastern Oyster (Crassostrea virginica)

The eastern oyster (Crassostrea virginica) supports a large aquaculture industry and is a keystone species along the Atlantic seaboard. Native oysters are routinely exposed to a complex mixture of contaminants that increasingly includes pharmaceuticals and personal care products (PPCPs). Unfortunately, the biological effects of chemical mixtures on oysters are poorly understood. Untargeted gas chromatography-mass spectrometry metabolomics was utilized to quantify the response of oysters exposed to fluoxetine, N,N-diethyl-meta-toluamide, 17α-ethynylestradiol, diphenhydramine, and their mixture. Oysters were exposed to 1 µg/L of each chemical or mixture for 10 d, followed by an 8-d depuration period. Adductor muscle (n = 14/treatment) was sampled at days 0, 1, 5, 10, and 18. Trajectory analysis illustrated that metabolic effects and class separation of the treatments varied at each time point and that, overall, the oysters were only able to partially recover from these exposures post-depuration. Altered metabolites were associated with cellular energetics (i.e., Krebs cycle intermediates), as well as amino acid metabolism and fatty acids. Exposure to these PPCPs also affected metabolic pathways associated with anaerobic metabolism, osmotic stress, and oxidative stress, in addition to the physiological effects of each chemical's postulated mechanism of action. Following depuration, fewer metabolites were altered, but none of the treatments returned them to their initial control values, indicating that metabolic disruptions were long-lasting. Interestingly, the mixture did not directly cluster with individual treatments in the scores plot from partial least squares discriminant analysis, and many of its affected metabolic pathways were not well predicted from the individual treatments. The present study highlights the utility of untargeted metabolomics in developing exposure biomarkers for compounds with different modes of action in bivalves. Environ Toxicol Chem 2020;39:419-436. © 2019 SETAC.

Impact of pharmacological agents on mitochondrial function: a growing opportunity?

Present-day drug therapies provide clear beneficial effects as many diseases can be driven into remission and the symptoms of others can be efficiently managed; however, the success of many drugs is limited due to both patient non-compliance and adverse off-target or toxicity-induced effects. There is emerging evidence that many of these side effects are caused by drug-induced impairment of mitochondrial function and eventual mitochondrial dysfunction. It is imperative to understand how and why drug-induced side effects occur and how mitochondrial function is affected. In an aging population, age-associated drug toxicity is another key area of focus as the majority of patients on medication are older. Therefore, with an aging population possessing subtle or even more dramatic individual differences in mitochondrial function, there is a growing necessity to identify and understand early on potentially significant drug-associated off-target effects and toxicity issues. This will not only reduce the number of unwanted side effects linked to mitochondrial toxicity but also identify useful mitochondrial-modulating agents. Mechanistically, many successful drug classes including diabetic treatments, antibiotics, chemotherapies and antiviral agents have been linked to mitochondrial targeted effects. This is a growing area, with research to repurpose current medications affecting mitochondrial function being assessed in cancer, the immune system and neurodegenerative disorders including Parkinson's disease. Here, we review the effects that pharmacological agents have on mitochondrial function and explore the opportunities from these effects as potential disease treatments. Our focus will be on cancer treatment and immune modulation.

In vitro cytogenotoxic evaluation of sertraline

Sertraline (SRT) is an antidepressant agent used as a neuronal selective serotonin-reuptake inhibitor (SSRI). SRT blocks serotonin reuptake and increases serotonin stimulation of somatodendritic serotonin 1A receptor (5-HT1AR) and terminal autoreceptors in the brain. In the present study, the genotoxic potential of SRT was evaluated using cytokinesis-block micronucleus (CBMN) cytome assay in peripheral blood lymphocytes of healthy human subjects. DNA cleavage-protective effects of SRT were analyzed on plasmid pBR322. In addition, biochemical parameters of total oxidant status (TOS) and total antioxidant status (TAS) in blood plasma were measured to quantitate oxidative stress. Human peripheral blood lymphocytes were exposed to four different concentrations (1.25, 2.5, 3.75 and 5 μg/mL) of SRT for 24- or 48-h treatment periods. In this study, SRT was not found to induce MN formation either in 24- or 48-h treatment periods. In contrast, SRT concentration-dependently decreased the percentage of MN and MNBN (r=-0.979, p<0.01; r=-0.930, p<0.05, respectively) when it was present for the last 48 hr (48-h treatment) of the culture period. SRT neither demonstrated a cleavage activity on plasmid DNA nor conferred DNA protection against H₂O₂. The application of various concentrations of SRT significantly increased the TOS and oxidative stress index (OSI) in human peripheral blood lymphocytes for both the 24- and 48-h treatment periods. Morover, the increase in TOS was potent as the positive control MMC at both treatment times. However, SRT did not alter the TAS levels in either 24- or 48-h treatment periods when compared to control. In addition, exposing cells to SRT caused significant decreases in the nuclear division index at 1.25, 2.50 and 3.75 μg/mL in the 24-h and at the highest concentration (5 μg/mL) in the 48-h treatment periods. Our results suggest that SRT may have cytotoxic effect via oxidative stress on cultured human peripheral blood lymphocytes.

Efficacy of sertraline against Trypanosoma cruzi: an in vitro and in silico study

Background

Drug repurposing has been an interesting and cost-effective approach, especially for neglected diseases, such as Chagas disease.

Methods

In this work, we studied the activity of the antidepressant drug sertraline against Trypanosoma cruzi trypomastigotes and intracellular amastigotes of the Y and Tulahuen strains, and investigated its action mode using cell biology and in silico approaches.

Results

Sertraline demonstrated in vitro efficacy against intracellular amastigotes of both T. cruzi strains inside different host cells, including cardiomyocytes, with IC₅₀ values between 1 to 10 μM, and activity against bloodstream trypomastigotes, with IC₅₀ of 14 μM. Considering the mammalian cytotoxicity, the drug resulted in a selectivity index of 17.8. Sertraline induced a change in the mitochondrial integrity of T. cruzi, resulting in a decrease in ATP levels, but not affecting reactive oxygen levels or plasma membrane permeability. In silico approaches using chemogenomic target fishing, homology modeling and molecular docking suggested the enzyme isocitrate dehydrogenase 2 of T. cruzi (TcIDH2) as a potential target for sertraline.

Conclusions

The present study demonstrated that sertraline had a lethal effect on different forms and strains of T. cruzi, by affecting the bioenergetic metabolism of the parasite. These findings provide a starting point for future experimental assays and may contribute to the development of new compounds.

Electronic supplementary material

The online version of this article (10.1186/s40409-018-0165-8) contains supplementary material, which is available to authorized users.

In vivo investigation on the chronic hepatotoxicity induced by sertraline

Although sertraline is widely prescribed as relatively safe antidepressant drug, hepatic toxicity was reported in some patients with sertraline treatment. The present study was conducted to investigate the morphometric, hepatotoxicity, and change in gene expression of drug metabolizing enzymes. Male healthy adult rabbits (Oryctolagus cuniculus) ranging from 1050 to 1100 g were exposed to oral daily doses of sertraline (0, 1, 2, 4, 8 mg/kg) for 9 weeks. The animals were subjected to morphometric, hepatohistological, histochemical and quantitative real-time polymerase chain reaction analyses. Sertraline chronic exposure induced morphometric changes and provoked histological and histochemical alterations including: hepatocytes hydropic degeneration, necrosis, nuclear alteration, sinusoidal dilation, bile duct hyperplasia, inflammatory cells infiltration, portal vessel congestion, Kupffer cells hyperplasia, portal fibrosis and glycogen depletion. In addition, the gene expression of drug and arachidonic acid metabolizing enzymes were reduced significantly (p value <0.05). The most affected genes were cyp4a12, ephx2, cyp2d9 and cyp1a2, demonstrating 5 folds or more down-regulation. These findings suggest that chronic sertraline treatment induced toxic histological alterations in the hepatic tissues and reduced the gene expression of drug metabolizing enzymes. Patients on chronic sertraline treatment may be on risk of hepatotoxicity with reduced capacity to metabolize drugs and fatty acids.

Sertraline-induced reproductive toxicity in male rats: evaluation of possible underlying mechanisms

This study was conducted to clarify the toxic effects of sertraline (SRT) on the reproductive system of male rats and to elucidate the underlying mechanisms. Rats were treated orally with SRT at doses of 5, 10, and 20 mg kg-1 for 28 consecutive days. At the end of the treatment period, sperm concentration, sperm motility, and sperm morphology were investigated by computer-assisted sperm analysis system whereas sperm DNA damage was detected by comet assay. The oxidative status of the testes was investigated, and a histopathological examination was conducted. Serum testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels were measured to determine the effects of SRT on the spermatogenesis process. One-way ANOVA, post-hoc Dunnett's T3 test for the sperm comet assay, and post-hoc Tukey's test for the others were performed for statistical analysis. The results showed that SRT caused an increase in sperm DNA damage and induced histopathological lesions in all groups treated with SRT. There was abnormal sperm morphology and increased malondialdehyde (MDA) in the 10 mg kg-1 treatment group. More dramatic changes were observed in the 20 mg kg-1 treatment group. Decreased sperm count was accompanied by a significant increase in abnormal sperm morphology, DNA damage, and degeneration in cellular-tubular structures. Serum LH and testosterone levels were elevated in the 20 mg kg-1 treatment group. Decreased glutathione (GSH) and increased MDA were signs of enhanced oxidative stress (OS). In conclusion, SRT induced testicular toxicity in a dose-dependent manner and OS is suggested as a crucial mechanism.

Editor's Highlight: Therapeutic Concentrations of Antidepressants Inhibit Pancreatic Beta-Cell Function via Mitochondrial Complex Inhibition

Diabetes mellitus risk is increased by prolonged usage of antidepressants (ADs). Although various mechanisms are suggested for their diabetogenic potential, whether a direct effect of ADs on pancreatic β-cells is involved is unclear. We examined this idea for 3 ADs: paroxetine, clomipramine and, with particular emphasis, fluoxetine, on insulin secretion, mitochondrial function, cellular bioenergetics, KATP channel activity, and caspase activity in murine and human cell-line models of pancreatic β-cells. Metabolic assays showed that these ADs decreased the redox, oxidative respiration, and energetic potential of β-cells in a time and concentration dependent manner, even at a concentration of 100 nM, well within the therapeutic window. These effects were related to inhibition of mitochondrial complex I and III. Consistent with impaired mitochondrial function, lactate output was increased and insulin secretion decreased. Neither fluoxetine, antimycin nor rotenone could reactivate KATP channel activity blocked by glucose unlike the mitochondrial uncoupler, FCCP. Chronic, but not acute, AD increased oxidative stress and activated caspases, 3, 8, and 9. A close agreement was found for the rates of oxidative respiration, lactate output and modulation of KATP channel activity in MIN6 cells with those of primary murine cells; data that supports MIN6 as a valid model to study beta-cell bioenergetics. To conclude, paroxetine, clomipramine and fluoxetine were all cytotoxic at therapeutic concentrations on pancreatic beta-cells; an action suggested to arise by inhibition of mitochondrial bioenergetics, oxidative stress and induction of apoptosis. These actions help explain the diabetogenic potential of these ADs in humans.

Circulating cell-free mitochondrial DNA, but not leukocyte mitochondrial DNA copy number, is elevated in major depressive disorder

Major depressive disorder (MDD) has been linked to mitochondrial defects, which could manifest in mitochondrial DNA (mtDNA) polymorphisms or mutations. Additionally, copy number of mtDNA (mtDNA-cn) can be quantified in peripheral blood mononuclear cells (PBMC)s, indirectly reflecting cellular energetics, or in the circulating cell-free mtDNA (ccf-mtDNA) levels, which may reflect a fraction of the mitochondrial genome released during cellular stress. Few studies have examined ccf-mtDNA in MDD, and no studies have tested its relationship with intracellular mtDNA-cn or with antidepressant treatment response. Here, mtDNA levels were quantified in parallel from: (i) PBMCs and (ii) cell-free plasma of 50 unmedicated MDD subjects and 55 controls, in parallel with PBMC telomere length (TL) and antioxidant enzyme glutathione peroxidase (GpX) activity. MtDNA measures were repeated in 19 MDD subjects after 8 weeks of open-label SSRI treatment. In analyses adjusted for age, sex, BMI, and smoking, MDD subjects had significantly elevated levels of ccf-mtDNA (F = 20.6, p = 0.00002). PBMC mtDNA-cn did not differ between groups (p > 0.4). In preliminary analyses, we found that changes in ccf-mtDNA with SSRI treatment differed between SSRI responders and non-responders (F = 6.47, p = 0.02), with the non-responders showing an increase in ccf-mtDNA and responders not changing. Baseline ccf-mtDNA was positively correlated with GpX (r = 0.32, p = 0.001), and PBMC mtDNA correlated positively with PBMC TL (r = 0.38, p = 0.0001). These data suggest that plasma ccf-mtDNA and PBMC mtDNA-cn reflect different cellular processes and that the former may be more reflective of certain aspects of MDD pathophysiology and of the response to SSRI antidepressants.

The role of hepatic cytochrome P450s in the cytotoxicity of dronedarone

Dronedarone is used to treat patients with cardiac arrhythmias and has been reported to be associated with liver injury. Our previous mechanistic work demonstrated that DNA damage-induced apoptosis contributes to the cytotoxicity of dronedarone. In this study, we examined further the underlying mechanisms and found that after a 24-h treatment of HepG2 cells, dronedarone caused cytotoxicity, G1-phase cell cycle arrest, suppression of topoisomerase II, and DNA damage in a concentration-dependent manner. We also investigated the role of cytochrome P450s (CYPs)-mediated metabolism in the dronedarone-induced toxicity using our previously established HepG2 cell lines expressing individually 14 human CYPs (1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, 3A4, 3A5, and 3A7). We demonstrated that CYP3A4, 3A5, and 2D6 were the major enzymes that metabolize dronedarone, and that CYP3A7, 2E1, 2C19, 2C18, 1A1, and 2B6 also metabolize dronedarone, but to a lesser extent. Our data showed that the cytotoxicity of dronedarone was decreased in CYP3A4-, 3A5-, or 2D6-overexpressing cells compared to the control HepG2 cells, indicating that the parent dronedarone has higher potency than the metabolites to induce cytotoxicity in these cells. In contrast, cytotoxicity was increased in CYP1A1-overexpressing cells, demonstrating that CYP1A1 exerts an opposite effect in dronedarone's toxicity, comparing to CYP3A4, 3A5, or 2D6. We also studied the involvement of topoisomerase II in dronedarone-induced toxicity, and demonstrated that the overexpression of topoisomerase II caused an increase in cell viability and a decrease in γ-H2A.X induction, suggesting that suppression of topoisomerase II may be one of the mechanisms involved in dronedarone-induced liver toxicity.

Imidacloprid affects rat liver mitochondrial bioenergetics by inhibiting FoF1-ATP synthase activity

Imidacloprid (IMD) is a neonicotinoid insecticide widely used in crops, pets, and on farm animals for pest control. Several studies were conducted examining the adverse effects of IMD on animals often exhibiting hepatic damage. The aim of this study was to determine the effects of IMD on bioenergetics of mitochondria isolated from rat liver. Imidacloprid (50-200 µM) produced a concentration-dependent decrease in oxygen consumption and ATP production without markedly affecting mitochondrial membrane potential (MMP). Oxygen consumption experiments showed that IMD did not significantly affect the respiratory chain, and this was similar to findings with oligomycin and carboxyatractyloside, suggesting a direct action on F_oF₁-ATP synthase and/or the adenine nucleotide translocator (ANT). Imidacloprid inhibited F_oF₁-ATP synthase activity only in disrupted mitochondria and induced a partial inhibition of ADP-stimulated depolarization of the MMP. Our results indicate that IMD interacts specifically with F_oF₁-ATP synthase resulting in functional inhibition of the enzyme with consequent impairment of mitochondrial bioenergetics. These effects of IMD on mitochondrial bioenergetics may be related to adverse effects of this insecticide on the liver.

The interplay between inflammation, oxidative stress, DNA damage, DNA repair and mitochondrial dysfunction in depression

A growing body of evidence suggests that inflammation, mitochondrial dysfunction and oxidant-antioxidant imbalance may play a significant role in the development and progression of depression. Elevated levels of reactive oxygen and nitrogen species - a result of oxidant-antioxidant imbalance - may lead to increased damage of biomolecules, including DNA. This was confirmed in depressed patients in a research study conducted by our team and other scientists. 8-oxoguanine - a marker of oxidative DNA damage - was found in the patients' lymphocytes, urine and serum. These results were confirmed using a comet assay on lymphocytes. Furthermore, it was shown that the patients' cells repaired peroxide-induced DNA damage less efficiently than controls' cells and that some single nucleotide polymorphisms (SNP) of the genes involved in oxidative DNA damage repair may modulate the risk of depression. Lastly, less efficient DNA damage repair observed in the patients can be, at least partly, attributed to the presence of specific SNP variants, as it was revealed through a genotype-phenotype analysis. In conclusion, the available literature shows that both oxidative stress and less efficient DNA damage repair may lead to increased DNA damage in depressed patients. A similar mechanism may result in mitochondrial dysfunction, which is observed in depression.

Antidepressants, sertraline and paroxetine, increase calcium influx and induce mitochondrial damage-mediated apoptosis of astrocytes

The impacts of antidepressants on the pathogenesis of dementia remain unclear despite depression and dementia are closely related. Antidepressants have been reported may impair serotonin-regulated adaptive processes, increase neurological side-effects and cytotoxicity. An ‘astroglio-centric’ perspective of neurodegenerative diseases proposes astrocyte dysfunction is involved in the impairment of proper central nervous system functioning. Thus, defining whether antidepressants are harmful to astrocytes is an intriguing issue. We used an astrocyte cell line, primary cultured astrocytes and neuron cells, to identify the effects of 11 antidepressants which included selective serotonin reuptake inhibitors, a serotonin-norepinephrine reuptake inhibitor, tricyclic antidepressants, a tetracyclic antidepressant, a monoamine oxide inhibitor, and a serotonin antagonist and reuptake inhibitor. We found that treatment with 10 μM sertraline and 20 μM paroxetine significantly reduced cell viability. We further explored the underlying mechanisms and found induction of the [Ca²⁺]_i level in astrocytes. We also revealed that sertraline and paroxetine induced mitochondrial damage, ROS generation, and astrocyte apoptosis with elevation of cleaved-caspase 3 and cleaved-PARP levels. Ultimately, we validated these mechanisms in primary cultured astrocytes and neuron cells and obtained consistent results. These results suggest that sertraline and paroxetine cause astrocyte dysfunction, and this impairment may be involved in the pathogenesis of neurodegenerative diseases.

Rapid Ascending Sensorimotor Paralysis, Hearing Loss, and Fatal Arrhythmia in a Multimorbid Patient due to an Accidental Overdose of Fluoxetine

BACKGROUND

Common side effects of selective serotonin reuptake inhibitors (SSRIs) include tachycardia, drowsiness, tremor, nausea, and vomiting. Although SSRIs have less toxic side effects compared to more traditional antidepressants, serious and life threatening cases of SSRI overdose have been reported. We describe a 24-year-old multimorbid female who presented to the emergency department with rapid onset ascending sensorimotor paralysis, complicated by respiratory and cardiac arrest, found to have fatal levels of fluoxetine by toxicological analysis, not taken in a suicidal act.

RESULTS

Autopsy was performed at the Los Angeles County Medical Examiner's Office of a female with no evidence of traumatic injury. Toxicological analysis revealed lethal levels of fluoxetine, toxic levels of diphenhydramine, and multiple other coingested substances at nontoxic levels. Neuropathological examination of the brain and spinal cord revealed no evidence of Guillain-Barre paralysis.

CONCLUSIONS

Lethal levels of fluoxetine and multiple potential drug-to-drug interactions in our patient likely contributed to her unique signs and symptoms. This is the first case reporting neurologic signs and symptoms consisting of rapid onset ascending sensorimotor paralysis, hearing loss, respiratory failure, cardiac arrest, and death in a patient with lethal levels of fluoxetine.

Effect of contaminants of emerging concern on liver mitochondrial function in Chinook salmon

We previously reported the bioaccumulation of contaminants of emerging concern (CECs), including pharmaceuticals and personal care products (PPCPs) and perfluorinated compounds, in field-collected juvenile Chinook salmon from urban estuaries of Puget Sound, WA (Meador et al., 2016). Although the toxicological impacts of CECs on salmon are poorly understood, several of the detected contaminants disrupt mitochondrial function in other species. Here, we sought to determine whether environmental exposures to CECs are associated with hepatic mitochondrial dysfunction in juvenile Chinook. Fish were exposed in the laboratory to a dietary mixture of 16 analytes representative of the predominant CECs detected in our field study. Liver mitochondrial content was reduced in fish exposed to CECs, which occurred concomitantly with a 24-32% reduction in expression of peroxisome proliferator-activated receptor (PPAR) Y coactivator-1a (pgc-1α), a positive transcriptional regulator of mitochondrial biogenesis. The laboratory exposures also caused a 40-70% elevation of state 4 respiration per unit mitochondria, which drove a 29-38% reduction of efficiency of oxidative phosphorylation relative to controls. The mixture-induced elevation of respiration was associated with increased oxidative injury as evidenced by increased mitochondrial protein carbonyls, elevated expression of glutathione (GSH) peroxidase 4 (gpx4), a mitochondrial-associated GSH peroxidase that protects against lipid peroxidation, and reduction of mitochondrial GSH. Juvenile Chinook sampled in a WWTP effluent-impacted estuary with demonstrated releases of CECs showed similar trends toward reduced liver mitochondrial content and elevated respiratory activity per mitochondria (including state 3 and uncoupled respiration). However, respiratory control ratios were greater in fish from the contaminated site relative to fish from a minimally-polluted reference site, which may have been due to differences in the timing of exposure to CECs under laboratory and field conditions. Our results indicate that exposure to CECs can affect both mitochondrial quality and content, and support the analysis of mitochondrial function as an indicator of the sublethal effects of CECs in wild fish.