Profile of stress and toxicity gene expression in human hepatic cells treated with Efavirenz

Expression of HSPA14 in patients with acute HIV-1 infection and its effect on HIV-1 replication

Introduction

Heat shock protein (HSPs) are important intracellular factors, which are often involved in the regulation of viral replication including HIV-1 in infected individuals as molecular chaperone proteins. Heat shock proteins 70 (HSP70/HSPA) family play important roles in HIV replication, but this family contain many subtypes, and it is unclear how these subtypes participate in and affect HIV replication.

Methods

To detect the interaction between HSPA14 and HspBP1 by CO-IP. Simulating HIV infection status in vitro to detect the change of intracellular HSPA14 expression after HIV infection in different cells. Constructing HSPA14 overexpression or knockdown cells to detect intracellular HIV replication levels after in vitro infection. Detecting the difference of HSPA expression levels in CD4+ T cells of untreated acute HIV-infected patients with different viral load.

Results

In this study, we found that HIV infection can lead to changes in the transcriptional level of many HSPA subtypes, among which HSPA14 interacts with HIV transcriptional inhibitor HspBP1. The expression of HSPA14 in Jurkat and primary CD4+T cells infected with HIV were inhibited, overexpression of HSPA14 inhibited HIV replication, while knocking down HSPA14 promoted HIV replication. We also found that the expression level of HSPA14 is higher in peripheral blood CD4+T cells of untreated acute HIV infection patients with low viral load.

Conclusion

HSPA14 is a potential HIV replication inhibitor and may restrict HIV replication by regulating the transcriptional inhibitor HspBP1. Further studies are needed to determine the specific mechanism by which HSPA14 regulates viral replication.

Increased Circulating Levels of Growth Differentiation Factor 15 in Association with Metabolic Disorders in People Living with HIV Receiving Combined Antiretroviral Therapy

Objective: People living with HIV (PLWH) have an increased cardiovascular risk (CVR) owing to dyslipidemia, insulin resistance, metabolic syndrome, and HIV/combination antiretroviral therapy (cART)-associated lipodystrophy (HALS). Atherosclerosis and inflammation are related to growth differentiation factor-15 (GDF15). The relationship between metabolic disturbances, HALS, and CVR with GDF15 in PLWH is not known. Research design and methods: Circulating GDF15 levels in 152 PLWH (with HALS = 60, without HALS = 43, cART-naïve = 49) and 34 healthy controls were assessed in a cross-sectional study. Correlations with lipids, glucose homeostasis, fat distribution, and CVR were explored. Results: PLWH had increased circulating GDF15 levels relative to controls. The increase was the largest in cART-treated PLWH. Age, homeostatic model assessment of insulin resistance 1 (HOMA1-IR), HALS, dyslipidemia, C-reactive protein, and CVR estimated with the Framingham score correlated with GDF15 levels. The GDF15-Framingham correlation was lost after age adjustment. No correlation was found between GDF15 and the D:A:D Data Collection on Adverse Effects of Anti-HIV Drugs (D:A:D) score estimated CVR. CVR independent predictors were patient group (naïve, HALS−, and HALS+) and cumulated protease inhibitor or nucleoside reverse transcriptase inhibitor exposure. Conclusions: PLWH, especially when cART-treated, has increased GDF15 levels—this increase is associated with dyslipidemia, insulin resistance, metabolic syndrome, HALS, and inflammation-related parameters. GDF15 is unassociated with CVR when age-adjusted.

Macrophages Modulate Hepatic Injury Involving NLRP3 Inflammasome: The Example of Efavirenz

Drug-induced liver injury (DILI) constitutes a clinical challenge due to the incomplete characterization of the mechanisms involved and potential risk factors. Efavirenz, an anti-HIV drug, induces deleterious actions in hepatocytes that could underlie induction of the NLRP3 inflammasome, an important regulator of inflammatory responses during liver injury. We assessed the potential of efavirenz to modulate the inflammatory and fibrogenic responses of major liver cell types involved in DILI. The effects of efavirenz were evaluated both in vitro and in vivo. Efavirenz triggered inflammation in hepatocytes, in a process that involved NF-κB and the NLRP3 inflammasome, and activated hepatic stellate cells (HSCs), thereby enhancing expression of inflammatory and fibrogenic markers. The NLRP3 inflammasome was not altered in efavirenz-treated macrophages, but these cells polarized towards the anti-inflammatory M2 phenotype and displayed upregulated anti-inflammatory mediators. Conversely, no evidence of damage was observed in efavirenz-treated animals, except when macrophages were depleted, which resulted in the in vivo manifestation of the deleterious effects detected in hepatocytes and HSCs. Efavirenz elicits a cell-specific activation of the NLRP3 inflammasome in hepatocytes and HSCs, but macrophages appear to counteract efavirenz-induced liver injury. Our results highlight the dynamic nature of the interaction among liver cell populations and emphasize the potential of targeting macrophage polarization as a strategy to treat NLRP3 inflammasome-induced liver injury.

Switch to Efavirenz Attenuates Lipoatrophy in Girls With Perinatal HIV

OBJECTIVES

Children with HIV (CHIV) have lifetime exposure to antiretrovirals (ART); therefore, optimizing their regimens to have the least impact on fat redistribution is a priority.

METHODS

This is a cross-sectional study of 219 perinatally infected CHIV and 219 HIV-uninfected controls from similar socioeconomic backgrounds in Johannesburg, South Africa. We compared total body and regional fat distribution in CHIV on suppressive ART regimens with controls and, among CHIV, between ritonavir-boosted lopinavir (LPV/r)-based and efavirenz (EFV)-based regimens.

RESULTS

The mean age of the 219 uninfected children (45% girls) and the 219 CHIV (48% girls) was 7.0 and 6.4 years, respectively. CHIV had lower adjusted total body fat (P = 0.005) and lower percentage fat at the trunk (P = 0.020), arms (P = 0.001), and legs (P < 0.001) than uninfected children. CHIV on LPV/r had similar body composition as those on EFV, except for arm fat mass (P = 0.030). When stratified by sex, girls with HIV on LPV/r had lower adjusted total (P = 0.007), trunk (P = 0.002), arms (P = 0.008), legs (P = 0.048) fat mass; trunk-to-total body fat (P = 0.044); and higher legs-to-total body fat (P = 0.011) than those on EFV.

CONCLUSIONS

South African CHIV receiving ART had lower global and partial fat mass and percentage fat than healthy controls. In girls with HIV with sustained virologic suppression on ART, switching from LPV/r to EFV could attenuate fat mass loss, indicating that EFV-based regimen may be a better option in this group of individuals.

Genomic Instability Decreases in HIV Patient by Complementary Therapy with Rosmarinus officinalis Extracts

Genomic instability is associated with increased oxidative stress in patients with human immunodeficiency virus (HIV). The aim of this study was to determine the effect of intake of methanolic and aqueous extracts of Rosmarinus officinalis on genomic instability in HIV patients. We studied 67 HIV patients under pharmacological treatment with ATRIPLA who were divided into three groups: group 1, patients under ATRIPLA antiretroviral therapy; group 2, patients with ATRIPLA and rosemary aqueous extract (4 g/L per day); and group 3, patients with ATRIPLA and rosemary methanolic extract (400 mg/day). The genomic instability was evaluated through the buccal micronucleus cytome assay. Oral epithelial cells were taken at the beginning and 1 and 4 months later. The groups that received the pharmacological therapy with ATRIPLA and the complementary therapy with R. officinalis extracts showed a decrease in the number of cells with micronuclei and nuclear abnormalities compared with the group that only received ATRIPLA. The complementary therapy with R. officinalis decreased the genomic instability in HIV patients.

Validation of exercise-response genes in skeletal muscle cells of Thoroughbred racing horses

Objective

To understand the athletic characteristics of Thoroughbreds, high-throughput analysis has been conducted using horse muscle tissue. However, an in vitro system has been lacking for studying and validating genes from in silico data. The aim of this study is to validate genes from differentially expressed genes (DEGs) of our previous RNA-sequencing data in vitro. Also, we investigated the effects of exercise-induced stress including heat, oxidative, hypoxic and cortisol stress on horse skeletal muscle derived cells with the top six upregulated genes of DEGs.

Methods

Enriched pathway analysis was conducted using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) tool with upregulated genes in horse skeletal muscle tissue after exercise. Among the candidates, the top six genes were analysed through geneMANIA to investigate gene networks. Muscle cells derived from neonatal horse skeletal tissue were maintained and subjected to exercise-related stressors. Transcriptional changes in the top six genes followed by stressors were investigated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR).

Results

The inflammation response pathway was the most commonly upregulated pathway after horse exercise. Under non-cytotoxic conditions of exercise-related stressors, the transcriptional response of the top six genes was different among types of stress. Oxidative stress yielded the most similar expression pattern to DEGs.

Conclusion

Our results indicate that transcriptional change after horse exercise in skeletal muscle tissue strongly relates to stress response. The qRT-PCR results showed that stressors contribute differently to the transcriptional regulation. These results would be valuable information to understand horse exercise in the stress aspect.

In vitro-in vivo correlation of the drug-drug interaction potential of antiretroviral HIV treatment regimens on CYP1A1 substrate riociguat

Objectives: Riociguat is a soluble guanylate cyclase stimulator licensed for the treatment of pulmonary arterial hypertension (PAH), a potentially fatal complication of human immunodeficiency virus infection. This study investigated the inhibitory potency of selected antiretroviral regimens on the metabolic clearance of riociguat.Methods: The inhibitory potential of the components of six antiretroviral combinations (ATRIPLA® (efavirenz/emtricitabine/tenofovir disoproxil), COMPLERA® (rilpivirine/emtricitabine/tenofovir disoproxil), STRIBILD® (elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil), TRIUMEQ® (abacavir/dolutegravir/lamivudine), and two ritonavir-boosted regimens) on riociguat metabolism were evaluated in recombinant human CYP1A1 and CYP3A4 as well as in human hepatocytes exhibiting both CYP1A1 and CYP3A4 activity. In vitro-in vivo correlation was performed between calculated and observed increases in riociguat exposure in vivo.Results: Using both in vitro systems, the predicted increase in exposure of riociguat was highest with components of TRIUMEQ® followed by COMPLERA®, ATRIPLA®, STRIBILD®, and the ritonavir-boosted regimens. Further experiments in human hepatocytes confirmed CYP1A1 to be the predominant enzyme in the metabolic clearance of riociguat.Conclusion: Antiretroviral treatment containing the potent CYP1A1 inhibitor abacavir had the greatest impact on riociguat metabolic clearance. The impact of comedications containing only strong CYP3A4 inhibitors e.g. ritonavir was less pronounced, suggesting a benefit of riociguat over PAH-targeting medications with contraindications for use with strong CYP3A4 inhibitors.

Is low-level HIV-1 viraemia associated with elevated levels of markers of immune activation, coagulation and cardiovascular disease?

OBJECTIVES

The clinical significance of low-level viraemia (LLV) during antiretroviral therapy (ART) is debated. We retrospectively investigated longitudinal levels of plasma markers associated with inflammation, altered coagulation and cardiovascular disease in Swedish HIV-positive adults in relation to LLV or permanent virological suppression during long-term ART.

METHODS

Plasma levels of C-reactive protein (CRP), D-dimer, vascular cell adhesion molecule 1 (VCAM-1), suppression of tumorigenicity 2 (ST2), growth differentiation factor 15 (GDF-15), soluble CD14 (sCD14), soluble CD163 (sCD163), interferon-γ-induced protein 10 (IP-10) and β-2-microglobulin were measured in 34 individuals with LLV (viral load 50-999 HIV-1 RNA copies/mL) and in matched controls with persistent virological suppression. Biomarker levels were analysed in samples obtained during episodes of LLV and follow-up samples obtained 1 year later (with similar timing for controls). All biomarkers were analysed using an independent sample t-test and analysis of covariance (ANCOVA) after logarithmic transformation. Log-rank analysis was applied for markers with concentration values out of range.

RESULTS

Compared with controls, patients with LLV had significantly higher levels of GDF-15 [geometric mean 3416 (95% confidence interval (CI) 804-14 516) pg/mL versus 2002 (95% CI 355-11 295) pg/mL in controls; P = 0.026] and D-dimer [mean 1114 (95% CI 125-9917) ng/mL versus 756 (95% CI 157-3626) ng/mL; P = 0.038] after adjustment for age, CD4 count nadir and type of ART. In the unadjusted t-test, only GDF-15 was significantly higher and in the log-rank test, both GDF-15 and D-dimer were significantly elevated. No significant differences were observed for the other biomarkers analysed.

CONCLUSIONS

Although levels of inflammation markers were similar in ART recipients with and without LLV, persons with LLV had significantly higher levels of GDF-15 and D-dimer. These findings suggest a potential link between LLV and cardiovascular outcomes.

Toxicant-mediated redox control of proteostasis in neurodegeneration

Disruption in redox signaling and control of cellular processes has emerged as a key player in many pathologies including neurodegeneration. As protein aggregations are a common hallmark of several neuronal pathologies, a firm understanding of the interplay between redox signaling, oxidative and free radical stress, and proteinopathies is required to sort out the complex mechanisms in these diseases. Fortunately, models of toxicant-induced neurodegeneration can be utilized to evaluate and report mechanistic alterations in the proteostasis network (PN). The epidemiological links between environmental toxicants and neurological disease gives further credence into characterizing the toxicant-mediated PN disruptions observed in these conditions. Reviewed here are examples of mechanistic interaction between oxidative or free radical stress and PN alterations. Additionally, investigations into toxicant-mediated PN disruptions, specifically focusing on environmental metals and pesticides, are discussed. Finally, we emphasize the need to distinguish whether the presence of protein aggregations are contributory to phenotypes related to neurodegeneration, or if they are a byproduct of PN deficiencies.

Cytotoxic effect of Efavirenz in BxPC-3 pancreatic cancer cells is based on oxidative stress and is synergistic with ionizing radiation

The non-nucleoside reverse transcriptase inhibitor (NNRTI) Efavirenz is frequently used in human immunodeficiency virus treatment, but also efficient against cancer in mouse models. Its radiosensitizing effect makes it a promising drug for combination with radiotherapy. The efficacy of Efavirenz combined with irradiation was assessed with immunostaining of DNA-damage markers and colony formation assays in BxPC-3 pancreatic cancer cells. Gene expression and protein phosphorylation of the Efavirenz-sensitive BxPC-3 cells was compared to the resistant primary fibroblasts SBL-5. Oxidative stress, mitochondrial damage and cell death were studied with live-cell microscopy and flow cytometry. Combined Efavirenz and radiation significantly increased the number of γH2AX and phospho-ataxia telangiectasia mutated foci. Efavirenz and ionizing radiation had a synergistic effect using the clonogenic survival assay. Efavirenz selectively induced cell death in the BxPC-3 cells. The differing gene expression of cell cycle and apoptotic regulator genes in both cell cultures after Efavirenz treatment match with this selective effect against cancer cells. In the phosphoprotein array, an early phosphorylation of extracellular signal-related kinase 1/2 and p38 mitogen-activated protein kinase was notably detected in the cancer cells. The phosphorylation of AKT decreased in the cancer cells whereas it increased in the fibroblasts. Oxidative stress and mitochondrial membrane depolarization appeared in the cancer cells immediately after Efavirenz treatment, but not in the fibroblasts. Efavirenz has an anti-cancer effect against pancreatic cancer mainly by the induction of oxidative stress. The antitumor potential of Efavirenz and radiotherapy are additive.

Efavirenz: What is known about the cellular mechanisms responsible for its adverse effects

The HIV infection remains an important health problem worldwide. However, due to the efficacy of combined antiretroviral therapy (cART), it has ceased to be a mortal condition, becoming a chronic disease instead. Efavirenz, the most prescribed non-nucleoside analogue reverse transcriptase inhibitor (NNRTI), has been a key component of cART since its commercialization in 1998. Though still a drug of choice in many countries, its primacy has been challenged by the arrival of newer antiretroviral agents with better toxicity profiles and treatment adherence. The major side effects related to EFV have been widely described in clinical studies, however the mechanisms that participate in their pathogenesis remain largely ununderstood. This review provides an insight into the cellular and molecular mechanisms responsible for the development of the most significant undesired effects induced by efavirenz, both short- and long-term, revealed by in vitro and in vivo experimental pharmacological research. Growing evidence implicates the drug in energy metabolism, mitochondrial function, and other cellular processes involved in stress responses including oxidative stress, inflammation and autophagy.

Efavirenz Causes Oxidative Stress, Endoplasmic Reticulum Stress, and Autophagy in Endothelial Cells

The non-nucleoside reverse transcriptase inhibitor efavirenz is a widely prescribed antiretroviral drug used in combined antiretroviral therapy. Despite being an essential and life-saving medication, the required lifelong use of HIV drugs has been associated with a variety of adverse effects, including disturbances in lipid metabolism and increased cardiovascular risk. Efavirenz belongs to those HIV drugs for which cardiovascular and endothelial dysfunctions have been reported. It is here shown that elevated concentrations of efavirenz can inhibit endothelial meshwork formation on extracellular matrix gels by normal and immortalized human umbilical vein cells. This inhibition was associated with an increase in oxidative stress markers, endoplasmic reticulum (ER) stress markers, and autophagy. Induction of ER stress occurred at pharmacologically relevant concentrations of efavirenz and resulted in reduced proliferation and cell viability of endothelial cells, which worsened in the presence of elevated efavirenz concentrations. In combination with the HIV protease inhibitor nelfinavir, both oxidative stress and ER stress became elevated in endothelial cells. These data indicate that pharmacologically relevant concentrations of efavirenz can impair cell viability of endothelial cells and that these effects may be aggravated by either elevated concentrations of efavirenz or by a combined use of efavirenz with other oxidative stress-inducing medications.

Depolarization of mitochondrial membrane potential is the initial event in non-nucleoside reverse transcriptase inhibitor efavirenz induced cytotoxicity

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and an active constituent of the highly active antiretroviral therapy regime. It has significantly contributed in control and management of human immunodeficiency virus propagation. However, EFV administration has also led to severe adverse effects, several reports highlighted the role of EFV in mitochondrial dysfunction and toxicity but the molecular mechanism has been poorly understood. In present study, human hepatoma cells Huh 7.5 were treated with clinically relevant concentrations of EFV and parameters like cytotoxicity, mitochondrial transmembrane potential, mitochondrial morphology, cytochrome c release, mitochondria-mediated apoptosis, mtDNA and mtRNA levels and EFV distribution into mitochondrial compartment were evaluated to understand sequence of events leading to cell death in EFV-treated cells. EFV at its clinically relevant concentration was significantly toxic after 48 and 72 h of treatments. EFV-mediated toxicity is initiated with the permeabilization of mitochondrial outer membrane and change in mitochondrial membrane potential (Δψm) which triggers a series of events like cytochrome c release, alteration in mitochondrial morphology and mitochondria-mediated apoptosis. Total mitochondrial content is reduced after 48 h of EFV treatment at IC₅₀ concentration which is also reflected in reduced mitochondrial DNA and RNA levels. After detecting EFV in mitochondrial compartment after 12 h of incubation with EFV, we hypothesize that EFV being a lipophilic molecule is internalized into the mitochondrial compartment causing depolarization of Δψm which subsequently leads to a cascade of events causing cell death.

Hazards of low dose flame-retardants (BDE-47 and BDE-32): Influence on transcriptome regulation and cell death in human liver cells

We have evaluated the in vitro low dose hepatotoxic effects of two flame-retardants (BDE-47 and BDE-32) in HepG2 cells. Both congeners declined the viability of cells in MTT and NRU cell viability assays. Higher level of intracellular reactive oxygen species (ROS) and dysfunction of mitochondrial membrane potential (ΔΨm) were observed in the treated cells. Comet assay data confirmed the DNA damaging potential of both congeners. BDE-47 exposure results in the appearance of subG1 apoptotic peak (30.1%) at 100 nM, while BDE-32 arrested the cells in G2/M phase. Among the set of 84 genes, BDE-47 induces downregulation of majority of mRNA transcripts, whilst BDE-32 showed differential expression of transcripts in HepG2. The ultrastructural analysis revealed mitochondrial swelling and degeneration of cristae in BDE-47 and BDE-32 treated cells. Overall our data demonstrated the hepatotoxic potential of both congeners via alteration of vital cellular pathways.

In-vitro effects of protease inhibitors on BAX, BCL- 2 and apoptosis in two human breast cell lines

Abstract Currently, the treatment of choice of HIV/AIDS in South Africa is the multidrug combination regimen known as HAART (highly active antiretroviral treatment). HAART, which commonly consists of nucleoside or non-nucleoside reverse transcriptase inhibitors and protease inhibitors, has radically decreased mortality and morbidity rates among people living with HIV/AIDS. The emphasis of the original development of the antiretroviral drugs was on clinical effectiveness (reducing mortality). Presently, emphasis has shifted from the initial short- term considerations to the long-term undesirable or harmful effects induced by this treatment regimen. Whether antiretroviral compounds are oncogenic is widely speculated, which led to this investigation into the effects of protease inhibitors on the expression of key apoptotic regulatory genes, BAX and BCL-2, in two human breast cell lines, MCF-7 and MCF-10A by real-time qPCR gene expression and immunofluorescence. The anti-apoptotic effects of the protease inhibitors – LPV/r were also investigated by cell death detection ELISA and acridine orange staining. This study also evaluated the cytotoxicity of the antiretroviral drugs in normal and cancer cell lines of the breast (at clinically relevant concentrations of the drugs and at different time points, 24–96 h), employing the neutral red uptake assay. The drugs and combinations tested did not alter BAX and BCL-2 gene expression and protein expression and localisation in both cell lines. In addition, the protease inhibitors–LPV/r did not inhibit camptothecin-induced apoptosis in both cell lines. We have shown that the protease inhibitors demonstrated varying degrees of cytotoxicity in the breast cells. The resulting DNA damage associated with cytotoxicity is strongly implicated in the processes of tumour initiation.

Efavirenz Has the Highest Anti-Proliferative Effect of Non-Nucleoside Reverse Transcriptase Inhibitors against Pancreatic Cancer Cells

Background

Cancer prevention and therapy in HIV-1-infected patients will play an important role in future. The non-nucleoside reverse transcriptase inhibitors (NNRTI) Efavirenz and Nevirapine are cytotoxic against cancer cells in vitro. As other NNRTIs have not been studied so far, all clinically used NNRTIs were tested and the in vitro toxic concentrations were compared to drug levels in patients to predict possible anti-cancer effects in vivo.

Methods

Cytotoxicity was studied by Annexin-V-APC/7AAD staining and flow cytometry in the pancreatic cancer cell lines BxPC-3 and Panc-1 and confirmed by colony formation assays. The 50% effective cytotoxic concentrations (EC50) were calculated and compared to the blood levels in our patients and published data.

Results

The in vitro EC50 of the different drugs in the BxPC-3 pancreatic cancer cells were: Efavirenz 31.5μmol/l (= 9944ng/ml), Nevirapine 239μmol/l (= 63786ng/ml), Etravirine 89.0μmol/l (= 38740ng/ml), Lersivirine 543μmol/l (= 168523ng/ml), Delavirdine 171μmol/l (= 78072ng/ml), Rilpivirine 24.4μmol/l (= 8941ng/ml). As Efavirenz and Rilpivirine had the highest cytotoxic potential and Nevirapine is frequently used in HIV-1 positive patients, the results of these three drugs were further studied in Panc-1 pancreatic cancer cells and confirmed with colony formation assays. 205 patient blood levels of Efavirenz, 127 of Rilpivirine and 31 of Nevirapine were analyzed. The mean blood level of Efavirenz was 3587ng/ml (range 162–15363ng/ml), of Rilpivirine 144ng/ml (range 0-572ng/ml) and of Nevirapine 4955ng/ml (range 1856–8697ng/ml). Blood levels from our patients and from published data had comparable Efavirenz levels to the in vitro toxic EC50 in about 1 to 5% of all patients.

Conclusion

All studied NNRTIs were toxic against cancer cells. A low percentage of patients taking Efavirenz reached in vitro cytotoxic blood levels. It can be speculated that in HIV-1 positive patients having high Efavirenz blood levels pancreatic cancer incidence might be reduced. Efavirenz might be a new option in the treatment of cancer.

Basal and stress-inducible expression of HSPA6 in human keratinocytes is regulated by negative and positive promoter regions

Epidermal keratinocytes serve as the primary barrier between the body and environmental stressors. They are subjected to numerous stress events and are likely to respond with a repertoire of heat shock proteins (HSPs). HSPA6 (HSP70B') is described in other cell types with characteristically low to undetectable basal expression, but is highly stress induced. Despite this response in other cells, little is known about its control in keratinocytes. We examined endogenous human keratinocyte HSPA6 expression and localized some responsible transcription factor sites in a cloned HSPA6 3 kb promoter. Using promoter 5' truncations and deletions, negative and positive regulatory regions were found throughout the 3 kb promoter. A region between -346 and -217 bp was found to be crucial to HSPA6 basal expression and stress inducibility. Site-specific mutations and DNA-binding studies show that a previously uncharacterized AP1 site contributes to the basal expression and maximal stress induction of HSPA6. Additionally, a new heat shock element (HSE) within this region was defined. While this element mediates increased transcriptional response in thermally stressed HaCaT keratinocytes, it preferentially binds a stress-inducible factor other than heat shock factor (HSF)1 or HSF2. Intriguingly, this newly characterized HSPA6 HSE competes HSF1 binding a consensus HSE and binds both HSF1 and HSF2 from other epithelial cells. Taken together, our results demonstrate that the HSPA6 promoter contains essential negative and positive promoter regions and newly identified transcription factor targets, which are key to the basal and stress-inducible expression of HSPA6. Furthermore, these results suggest that an HSF-like factor may preferentially bind this newly identified HSPA6 HSE in HaCaT cells.

Metabolic and body composition effects of newer antiretrovirals in HIV-infected patients

In the absence of a cure, HIV-infected patients are being successfully treated with antiretroviral therapies (ART) and living longer. Indeed, an increasing number of HIV-infected patients are living beyond the age of 50 years, and in that regard, the use of ART has transformed HIV into a chronic medical condition. As more HIV-infected patients are virologically controlled and living longer, the trajectory of disease morbidity has shifted, however, primarily from opportunistic infections and immune dysfunction to metabolic complications. Evidence suggests that HIV-infected patients acquire significant metabolic risks, including lipodystrophic changes, subclinical atherosclerosis, and insulin resistance. The etiology of these metabolic complications specifically in HIV-infected patients is not entirely clear but may be related to a complex interaction between long-term consequences of infection and HIV itself, chronic use of antiretrovirals, and underlying inflammatory processes. Previous classes of ART, such as protease inhibitors (PIs) and reverse transcriptase inhibitors, have been implicated in altering fat redistribution and lipid and glucose homeostasis. Advances in drug development have introduced newer ART with strategies to target novel mechanisms of action and improve patient adherence with multi-class drug combinations. In this review, we will focus on these newer classes of ART, including selected entry inhibitors, integrase inhibitors, and multi-class drug combinations, and two newer PIs, and the potential of these newer agents to cause metabolic complications in HIV-infected patients. Taken together, further reduction of morbidity in HIV-infected patients will require increasing awareness of the deleterious metabolic complications of ART with subsequent management to mitigate these risks.

Efavirenz promotes β-secretase expression and increased Aβ1-40,42 via oxidative stress and reduced microglial phagocytosis: implications for HIV associated neurocognitive disorders (HAND)

Efavirenz (EFV) is among the most commonly used antiretroviral drugs globally, causes neurological symptoms that interfere with adherence and reduce tolerability, and may have central nervous system (CNS) effects that contribute in part to HIV associated neurocognitive disorders (HAND) in patients on combination antiretroviral therapy (cART). Thus we evaluated a commonly used EFV containing regimen: EFV/zidovudine (AZT)/lamivudine (3TC) in murine N2a cells transfected with the human “Swedish” mutant form of amyloid precursor protein (SweAPP N2a cells) to assess for promotion of amyloid-beta (Aβ) production. Treatment with EFV or the EFV containing regimen generated significantly increased soluble amyloid beta (Aβ), and promoted increased β-secretase-1 (BACE-1) expression while 3TC, AZT, or, vehicle control did not significantly alter these endpoints. Further, EFV or the EFV containing regimen promoted significantly more mitochondrial stress in SweAPP N2a cells as compared to 3TC, AZT, or vehicle control. We next tested the EFV containing regimen in Aβ - producing Tg2576 mice combined or singly using clinically relevant doses. EFV or the EFV containing regimen promoted significantly more BACE-1 expression and soluble Aβ generation while 3TC, AZT, or vehicle control did not. Finally, microglial Aβ phagocytosis was significantly reduced by EFV or the EFV containing regimen but not by AZT, 3TC, or vehicle control alone. These data suggest the majority of Aβ promoting effects of this cART regimen are dependent upon EFV as it promotes both increased production, and decreased clearance of Aβ peptide.

Mechanisms of isoniazid-induced idiosyncratic liver injury: emerging role of mitochondrial stress

Idiosyncratic drug-induced liver injury (DILI) is a significant adverse effect of antitubercular therapy with isoniazid (INH). Although the drug has been used for many decades, the underlying mode of action (both patient-specific and drug-specific mechanisms) leading to DILI are poorly understood. Among the patient-specific determinants of susceptibility to INH-associated DILI, the importance of HLA genetic variants has been increasingly recognized, whereas the role of polymorphisms of drug-metabolizing enzymes (NAT2 and CYP2E1) has become less important and remains controversial. However, these polymorphisms are merely correlative, and other molecular determinants of susceptibility have remained largely unknown. Regarding the drug-specific mechanisms underlying INH-induced liver injury, novel concepts have been emerging. Among these are covalent protein adduct formation via novel reactive intermediates, leading to hapten formation and a potential immune response, and interference with endogenous metabolism. Furthermore, INH and/or INH metabolites (e.g. hydrazine) can cause mitochondrial injury, which can lead to mitochondrial oxidant stress and impairment of energy homeostasis. Recent studies have revealed that underlying impairment of complex I function can trigger massive hepatocellular injury induced by otherwise nontoxic concentrations of INH superimposed on these mitochondrial deficiencies. This review discusses these emerging new paradigms of INH-induced DILI and highlights recent insights into the mechanisms, as well as points to the existing large gaps in our understanding of the pathogenesis.

Bypassing the compromised mitochondrial electron transport with methylene blue alleviates efavirenz/isoniazid-induced oxidant stress and mitochondria-mediated cell death in mouse hepatocytes

Efavirenz (EFV) is an anti-retroviral drug frequently combined with isoniazid (INH) to treat HIV-1/tuberculosis co-infected patients. Both drugs have been associated with idiosyncratic liver injury (DILI), but combined anti-retroviral and anti-tubercular therapy can increase the risk for DILI as compared to either drug class alone. Because both EFV and INH have been implicated in targeting mitochondria, we aimed at exploring whether the two drugs might cause synergistic effects on the electron transport chain. We found that EFV inhibited complex I activity in isolated mouse liver mitochondria (IC50 ˜30 μM), whereas hydrazine, a major metabolite of INH generated by acylamidase-mediated hydrolytic cleavage, inhibited complex II activity (IC50 ˜30 μM). Neither INH alone (≤1000 μM) nor EFV alone (≤30 μM) was able to induce cell injury in cultured mouse hepatocytes. However, combined EFV/INH exposure resulted in increased superoxide formation and peroxynitrite stress, leading to the opening of the cyclosporine A-insensitive mode of the mitochondrial permeability transition (mPT), and necrotic cell death. The peroxynitrite scavengers, CBA or Fe-TMPyP, protected against mPT induction and alleviated cell injury. The acylamidase inhibitor bis-p-nitrophenyl phosphate prevented cell injury, suggesting that hydrazine greatly contributed to the toxicity. Methylene blue, a redox-active alternative electron acceptor/donor that bypasses complex I/II, effectively protected against EFV/INH-induced toxicity. These data demonstrate that, in murine hepatocytes, the mitochondrial electron transport chain is a critical target of combined EFV/INH exposure, and that this drug combination can lead to peroxynitrite stress-induced mPT and hepatocellular necrosis. These results are compatible with the concept that underlying silent mitochondrial dysfunction may be a key susceptibility factor contributing to idiosyncratic drug-induced liver injury.

Silver nanoparticles induced changes in the expression of NF-κB related genes are cell type specific and related to the basal activity of NF-κB

Silver nanoparticles (AgNPs) are widely used in industry and medicine but the recent evidence for their cytotoxicity rise a concern about the safety of their use. We have previously shown that human A549 cells are resistant to AgNPs cytotoxicity, as compared with similarly treated HepG2 cells. In order to check for the role of the NF-κB signaling pathway in response of A549 and HepG2 cell lines to the treatment with 20 nm and 200 nm AgNps, we analyzed the expression of 84 key genes related to the functionality of the NF-κB signaling pathway. We observed considerable alternations in gene expression in HepG2 cells treated with 20 nm AgNPs, and minor changes when exposed to 200 nm AgNPs. Surprisingly, no changes in gene expression were observed in A549 cells treated with both size AgNPs. Using the NF-κB luciferase reporter system, we further tested the basal activity and inducibility of the NF-κB pathway in both cell lines and found that the inducibility of NF-κB signaling in A549 cells is approximately 5 times lower than this of HepG2 cells, but the basal activity is approximately 3.5 times higher. In accordance, the NF-κB activation after AgNPs treatment was observed in HepG2 but not in A549. Altogether indicate that NF-kB mediated cellular response to AgNPs is cell type specific and related to the basal activity of NF-κB.

Endoplasmic reticulum stress in drug- and environmental toxicant-induced liver toxicity

Liver injury resulting from exposure to drugs and environmental chemicals is a major health problem. Endoplasmic reticulum stress (ER stress) is considered to be an important factor in a wide range of diseases, such as cancer, neurological and cardiovascular disease, diabetes, and inflammatory diseases. The role of ER stress in drug-induced and environmental toxicant-induced liver toxicity has been underestimated in the past; emerging evidence indicates that ER stress makes a substantial contribution to the pathogenesis of drug-induced liver toxicity. In this review, we summarize current knowledge on drugs and environmental toxicants that trigger ER stress in liver and on the underlying molecular mechanisms. We also discuss experimental approaches for ER stress studies.

Effect of antiretroviral drugs on the DNA damage in mice

In order to investigate the effects of two non-nucleoside reverse transcriptase inhibitors (NNRTIs) on the DNA damage in vivo, nevirapine (NVP; 3.3 mg/kg), efavirenz (EFV; 10 mg/kg) or saline were administered orally. Acute effects were analyzed 24 h after the administration of a single NNRTI dose, and subchronic effects 24 h after the last dose. Peripheral blood, brain, heart and liver samples were subjected to genotoxicity analyses and polychromatic erythrocytes from the bone marrow to micronucleus test. The micronucleus test did not reveal any significant differences between animals from the acute or subchronic groups. Comet assay showed that acute and subchronic NNRTI treatment did not cause any significant DNA damage in heart, liver or peripheral blood cells. However, increased damage indexes and frequencies were observed in the brain of mice, subchronically treated with EFV. This result suggests for the first time that this drug might induce genotoxicity in the brain.

ER stress in human hepatic cells treated with Efavirenz: mitochondria again

BACKGROUND & AIMS

ER stress is associated with a growing number of liver diseases, including drug-induced hepatotoxicity. The non-nucleoside analogue reverse transcriptase inhibitor Efavirenz, a cornerstone of the multidrug strategy employed to treat HIV1 infection, has been related to the development of various adverse events, including metabolic disturbances and hepatic toxicity, the mechanisms of which remain elusive. Recent evidence has pinpointed a specific mitochondrial effect of Efavirenz in human hepatic cells. This study assesses the induction of ER stress by Efavirenz in the same model and the implication of mitochondria in this process.

METHODS

Primary human hepatocytes and Hep3B were treated with clinically relevant concentrations of Efavirenz and parameters of ER stress were studied using standard cell biology techniques.

RESULTS

ER stress markers, including CHOP and GRP78 expression (both protein and mRNA), phosphorylation of eIF2α, and presence of the spliced form of XBP1 were upregulated. Efavirenz also enhanced cytosolic Ca(2+) content and induced morphological changes in the ER suggestive of ER stress. This response was greatly attenuated in cells with altered mitochondrial function (Rho°). The effects of Efavirenz on the ER, and particularly in regard to the mitochondrial involvement, differed from those elicited by a standard pharmacological ER stressor.

CONCLUSIONS

This newly discovered mechanism of cellular insult involving ER stress and UPR response may help comprehend the hepatic toxicity that has been associated with the widespread and life-long use of Efavirenz. In addition, the specificity of the actions of Efavirenz observed expands our knowledge of the mechanisms that trigger ER stress and shed some light on the mitochondria/ER interplay in drug-induced hepatic challenge.

HIV treatments have malaria gametocyte killing and transmission blocking activity

BACKGROUND

 Millions of individuals being treated for human immunodeficiency virus (HIV) live in malaria-endemic areas, but the effects of these treatments on malaria transmission are unknown. While drugs like HIV protease inhibitors (PIs) and trimethoprim-sulfamethoxazole (TMP-SMX) have known activity against parasites during liver or asexual blood stages, their effects on transmission stages require further study.

METHODS

 The HIV PIs lopinavir and saquinavir, the nonnucleoside reverse-transcriptase inhibitor nevirapine, and the antibiotic TMP-SMX were assessed for activity against Plasmodium falciparum transmission stages. The alamarBlue assay was used to determine the effects of drugs on gametocyte viability, and exflagellation was assessed to determine the effects of drugs on gametocyte maturation. The effects of drug on transmission were assessed by calculating the mosquito oocyst count as a marker for infectivity, using standard membrane feeding assays.

RESULTS

 Lopinavir and saquinavir have gametocytocidal and transmission blocking activities at or approaching clinically relevant treatment levels, while nevirapine does not. TMP-SMX is not gametocytocidal, but at prophylactic levels it blocks transmission.

CONCLUSIONS

 Specific HIV treatments have gametocyte killing and transmission-blocking effects. Clinical studies are warranted to evaluate these findings and their potential impact on eradication efforts.

HIV nonnucleoside reverse transcriptase inhibitors and trimethoprim-sulfamethoxazole inhibit plasmodium liver stages

BACKGROUND

Although nonnucleoside reverse transcriptase inhibitors (NNRTIs) are usually part of first-line treatment regimens for human immunodeficiency virus (HIV), their activity on Plasmodium liver stages remains unexplored. Additionally, trimethoprim-sulfamethoxazole (TMP-SMX), used for opportunistic infection prophylaxis in HIV-exposed infants and HIV-infected patients, reduces clinical episodes of malaria; however, TMP-SMX effect on Plasmodium liver stages requires further study.

METHODS

We characterized NNRTI and TMP-SMX effects on Plasmodium liver stages in vivo using Plasmodium yoelii. On the basis of these results, we conducted in vitro studies assessing TMP-SMX effects on the rodent parasites P. yoelii and Plasmodium berghei and on the human malaria parasite Plasmodium falciparum.

RESULTS

Our data showed NNRTI treatment modestly reduced P. yoelii liver stage parasite burden and minimally extended prepatent period. TMP-SMX administration significantly reduced liver stage parasite burden, preventing development of patent parasitemia in vivo. TMP-SMX inhibited development of rodent and P. falciparum liver stage parasites in vitro.

CONCLUSIONS

NNRTIs modestly affect liver stage Plasmodium parasites, whereas TMP-SMX prevents patent parasitemia. Because drugs that inhibit liver stages target parasites when they are present in lower numbers, these results may have implications for eradication efforts. Understanding HIV drug effects on Plasmodium liver stages will aid in optimizing treatment regimens for HIV-exposed and HIV-infected infected patients in malaria-endemic areas.