Representative Rodent Models for Renal Transporter Alterations in Human Nonalcoholic Steatohepatitis.

Alterations in renal elimination processes of glomerular filtration and active tubular secretion by renal transporters can result in adverse drug reactions. Nonalcoholic steatohepatitis (NASH) alters hepatic transporter expression and xenobiotic elimination, but until recently, renal transporter alterations in NASH were unknown. This study investigates renal transporter changes in rodent models of NASH to identify a model that recapitulates human alterations. Quantitative protein expression by surrogate peptide liquid chromatography-coupled mass spectrometry (LC-MS/MS) on renal biopsies from NASH patients was used for concordance analysis with rodent models, including methionine/choline deficient (MCD), atherogenic (Athero), or control rats and Leprdb/db MCD (db/db), C57BL/6J fast-food thioacetamide (FFDTH), American lifestyle-induced obesity syndrome (ALIOS), or control mice. Demonstrating clinical similarity to NASH patients, db/db, FFDTH, and ALIOS showed decreases in glomerular filtration rate (GFR) by 76%, 28%, and 24%. Organic anion transporter 3 (OAT3) showed an upward trend in all models except the FFDTH (from 3.20 to 2.39 pmol/mg protein), making the latter the only model to represent human OAT3 changes. OAT5, a functional ortholog of human OAT4, significantly decreased in db/db, FFDTH, and ALIOS (from 4.59 to 0.45, 1.59, and 2.83 pmol/mg protein, respectively) but significantly increased for MCD (1.67 to 4.17 pmol/mg protein), suggesting that the mouse models are comparable to human for these specific transport processes. These data suggest that variations in rodent renal transporter expression are elicited by NASH, and the concordance analysis enables appropriate model selection for future pharmacokinetic studies based on transporter specificity. These models provide a valuable resource to extrapolate the consequences of human variability in renal drug elimination. SIGNIFICANCE STATEMENT: Rodent models of nonalcoholic steatohepatitis that recapitulate human renal transporter alterations are identified for future transporter-specific pharmacokinetic studies to facilitate the prevention of adverse drug reactions due to human variability.

Renal Transporter Alterations in Patients with Chronic Liver Diseases: Nonalcoholic Steatohepatitis, Alcohol-Associated, Viral Hepatitis, and Alcohol-Viral Combination.

Alterations in hepatic transporters have been identified in precirrhotic chronic liver diseases (CLDs) that result in pharmacokinetic variations causing adverse drug reactions (ADRs). However, the effect of CLD on the expression of renal transporters is unknown despite the overwhelming evidence of kidney injury in CLD patients. This study determines the transcriptomic and proteomic expression profiles of renal drug transporters in patients with defined CLD etiology. Renal biopsies were obtained from patients with a history of CLD etiologies, including nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (ALD), viral hepatitis C (HCV), and combination ALD/HCV. A significant decrease in organic anion transporter (OAT)-3 was identified in NASH, ALD, HCV, and ALD/HCV (1.56 ± 1.10; 1.01 ± 0.46; 1.03 ± 0.43; 0.86 ± 0.57 pmol/mg protein) relative to control (2.77 ± 1.39 pmol/mg protein). Additionally, a decrease was shown for OAT4 in NASH (24.9 ± 5.69 pmol/mg protein) relative to control (43.8 ± 19.9 pmol/mg protein) and in urate transporter 1 (URAT1) for ALD and HCV (1.56 ± 0.15 and 1.65 ± 0.69 pmol/mg protein) relative to control (4.69 ± 4.59 pmol/mg protein). These decreases in organic anion transporter expression could result in increased and prolonged systemic exposure to drugs and possible toxicity. Renal transporter changes, in addition to hepatic transporter alterations, should be considered in dose adjustments for CLD patients for a more accurate disposition profile. It is important to consider a multiorgan approach to altered pharmacokinetics of drugs prescribed to CLD patients to prevent ADRs and improve patient outcomes. SIGNIFICANCE STATEMENT: Chronic liver diseases are known to elicit alterations in hepatic transporters that result in a disrupted pharmacokinetic profile for various drugs. However, it is unknown if there are alterations in renal transporters during chronic liver disease, despite strong indications of renal dysfunction associated with chronic liver disease. Identifying renal transporter expression changes in patients with chronic liver disease facilitates essential investigations on the multifaceted relationship between liver dysfunction and kidney physiology to offer dose adjustments and prevent adverse drug reactions.

Increased Renal Expression of Complement Components in Patients With Liver Diseases: Nonalcoholic Steatohepatitis, Alcohol-Associated, Viral Hepatitis, and Alcohol-Viral Combination.

Inflammatory liver diseases, including nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (ALD), hepatitis C virus (HCV), and ALD/HCV, account for nearly 2 million deaths annually. Despite increasing evidence that liver dysfunction impacts renal physiology, there is limited supportive clinical information, due to limited diagnosis of liver disease, complexity in liver disease etiology, and inadequacy of renal function tests. Human kidney biopsies with liver and renal pathology were obtained from patients with nonalcoholic fatty liver disease (NAFLD), NASH, ALD, HCV, and ALD/HCV (n = 5-7). Each liver disease showed renal pathology with at least 50% interstitial nephritis, 50% interstitial fibrosis, and renal dysfunction by estimated glomerular filtration rate (NAFLD 36.7 ± 21.4; NASH 32.7 ± 15.0; ALD 16.0 ± 11.0; HCV 27.6 ± 11.5; ALD/HCV 21.0 ± 11.2 ml/min/1.73 m2). Transcriptomic analysis identified 55 genes with expression changes in a conserved direction in response to liver disease. Considering association with immune regulation, protein levels of alpha-2-macroglobulin, clusterin, complement C1q C chain (C1QC), CD163, and joining chain of multimeric IgA and IgM (JCHAIN) were further quantified by LC-MS/MS. C1QC demonstrated an increase in NASH, ALD, HCV, and ALD/HCV (42.9 ± 16.6; 38.8 ± 18.4; 39.0 ± 13.5; 40.1 ± 20.1 pmol/mg protein) relative to control (19.2 ± 10.4 pmol/mg protein; p ≤ 0.08). Renal expression changes identified in inflammatory liver diseases with interstitial pathology suggest the pathogenesis of liver associated renal dysfunction. This unique cohort overcomes diagnostic discrepancies and sample availability to provide insight for mechanistic investigations on the impact of liver dysfunction on renal physiology.

Role of Lung P450 Oxidoreductase in Paraquat-Induced Collagen Deposition in the Lung.

Paraquat (PQ) is an agrochemical known to cause pulmonary fibrosis. PQ-induced collagen deposition in the lung is thought to require enzymatic formation of PQ radicals, but the specific enzymes responsible for this bioactivation event in vivo have not been identified. We tested the hypothesis that lung P450 oxidoreductase (POR or CPR) is important in PQ-induced lung fibrosis in mice. A lung-Cpr-null mouse model was utilized, which undergoes doxycycline-induced, Cre recombinase-mediated deletion of the Por gene specifically in airway Club cells and alveolar type 2 cells in the lung. The lungs of lung-Cpr-null mice and their wild-type littermates were collected on day 15 after a single intraperitoneal injection of saline (control) or PQ (20 mg/kg). Lung tissue sections were stained with picrosirius red for detection of collagen fibrils. Fibrotic lung areas were found to be significantly smaller (1.6-fold for males and 1.4-fold for females) in PQ-treated lung-Cpr-null mice than in sex- and treatment-matched wild-type mice. The levels of collagen in lung tissue homogenate were also lower (1.4-2.3-fold; p < 0.05) in PQ-treated lung-Cpr-null mice compared to PQ-treated wild-type mice. In contrast, plasma PQ toxicokinetic profiles were not different between sex-matched wild-type and lung-Cpr-null mice. Taken together, these results indicate that lung POR plays an important role in PQ-induced pulmonary fibrosis.

Attenuated Ochratoxin A Transporter Expression in a Mouse Model of Nonalcoholic Steatohepatitis Protects against Proximal Convoluted Tubule Toxicity.

Ochratoxin A (OTA) is an abundant mycotoxin, yet the toxicological impact of its disposition is not well studied. OTA is an organic anion transporter (OAT) substrate primarily excreted in urine despite a long half-life and extensive protein binding. Altered renal transporter expression during disease, including nonalcoholic steatohepatitis (NASH), may influence response to OTA exposure, but the impact of NASH on OTA toxicokinetics, tissue distribution, and associated nephrotoxicity is unknown. By inducing NASH in fast food-dieted/thioacetamide-exposed mice, we evaluated the effect of NASH on a bolus OTA exposure (12.5 mg/kg by mouth) after 3 days. NASH mice presented with less gross toxicity (44% less body weight loss), and kidney and liver weights of NASH mice were 11% and 24% higher, respectively, than healthy mice. Organ and body weight changes coincided with reduced renal proximal tubule cells vacuolation, degeneration, and necrosis, though no OTA-induced hepatic lesions were found. OTA systemic exposure in NASH mice increased modestly from 5.65 ± 1.10 to 7.95 ± 0.61 mg*h/ml per kg BW, and renal excretion increased robustly from 5.55% ± 0.37% to 13.11% ± 3.10%, relative to healthy mice. Total urinary excretion of OTA increased from 24.41 ± 1.74 to 40.07 ± 9.19 µg in NASH mice, and kidney-bound OTA decreased by ∼30%. Renal OAT isoform expression (OAT1-5) in NASH mice decreased by ∼50% with reduced OTA uptake by proximal convoluted cells. These data suggest that NASH-induced OAT transporter reductions attenuate renal secretion and reabsorption of OTA, increasing OTA urinary excretion and reducing renal exposure, thereby reducing nephrotoxicity in NASH. SIGNIFICANCE STATEMENT: These data suggest a disease-mediated transporter mechanism of altered tissue-specific toxicity after mycotoxin exposure, despite minimal systemic changes to ochratoxin A (OTA) concentrations. Further studies are warranted to evaluate the clinical relevance of this functional model and the potential effect of human nonalcoholic steatohepatitis on OTA and other organic anion substrate toxicity.

Testicular disposition of clofarabine in rats is dependent on equilibrative nucleoside transporters.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children and adolescents. Although the 5-year survival rate is high, some patients respond poorly to chemotherapy or have recurrence in locations such as the testis. The blood-testis barrier (BTB) can prevent complete eradication by limiting chemotherapeutic access and lead to testicular relapse unless a chemotherapeutic is a substrate of drug transporters present at this barrier. Equilibrative nucleoside transporter (ENT) 1 and ENT2 facilitate the movement of substrates across the BTB. Clofarabine is a nucleoside analog used to treat relapsed or refractory ALL. This study investigated the role of ENTs in the testicular disposition of clofarabine. Pharmacological inhibition of the ENTs by 6-nitrobenzylthioinosine (NBMPR) was used to determine ENT contribution to clofarabine transport in primary rat Sertoli cells, in human Sertoli cells, and across the rat BTB. The presence of NBMPR decreased clofarabine uptake by 40% in primary rat Sertoli cells (p = .0329) and by 53% in a human Sertoli cell line (p = .0899). Rats treated with 10 mg/kg intraperitoneal (IP) injection of the NBMPR prodrug, 6-nitrobenzylthioinosine 5'-monophosphate (NBMPR-P), or vehicle, followed by an intravenous (IV) bolus 10 mg/kg dose of clofarabine, showed a trend toward a lower testis concentration of clofarabine than vehicle (1.81 ± 0.59 vs. 2.65 ± 0.92 ng/mg tissue; p = .1160). This suggests that ENTs could be important for clofarabine disposition. Clofarabine may be capable of crossing the human BTB, and its potential use as a first-line treatment to avoid testicular relapse should be considered.

Altered cisplatin pharmacokinetics during nonalcoholic steatohepatitis contributes to reduced nephrotoxicity.

Disease-mediated alterations to drug disposition constitute a significant source of adverse drug reactions. Cisplatin (CDDP) elicits nephrotoxicity due to exposure in proximal tubule cells during renal secretion. Alterations to renal drug transporter expression have been discovered during nonalcoholic steatohepatitis (NASH), however, associated changes to substrate toxicity is unknown. To test this, a methionine- and choline-deficient diet-induced rat model was used to evaluate NASH-associated changes to CDDP pharmacokinetics, transporter expression, and toxicity. NASH rats administered CDDP (6 mg/kg, i.p.) displayed 20% less nephrotoxicity than healthy rats. Likewise, CDDP renal clearance decreased in NASH rats from 7.39 to 3.83 mL/min, renal secretion decreased from 6.23 to 2.80 mL/min, and renal CDDP accumulation decreased by 15%, relative to healthy rats. Renal copper transporter-1 expression decreased, and organic cation transporter-2 and ATPase copper transporting protein-7b increased slightly, reducing CDDP secretion. Hepatic CDDP accumulation increased 250% in NASH rats relative to healthy rats. Hepatic organic cation transporter-1 induction and multidrug and toxin extrusion protein-1 and multidrug resistance-associated protein-4 reduction may contribute to hepatic CDDP sequestration in NASH rats, although no drug-related toxicity was observed. These data provide a link between NASH-induced hepatic and renal transporter expression changes and CDDP renal clearance, which may alter nephrotoxicity.

Predicting Drug Interactions with Human Equilibrative Nucleoside Transporters 1 and 2 Using Functional Knockout Cell Lines and Bayesian Modeling.

Equilibrative nucleoside transporters (ENTs) 1 and 2 facilitate nucleoside transport across the blood-testis barrier (BTB). Improving drug entry into the testes with drugs that use endogenous transport pathways may lead to more effective treatments for diseases within the reproductive tract. In this study, CRISPR/CRISPR-associated protein 9 was used to generate HeLa cell lines in which ENT expression was limited to ENT1 or ENT2. We characterized uridine transport in these cell lines and generated Bayesian models to predict interactions with the ENTs. Quantification of [3H]uridine uptake in the presence of the ENT-specific inhibitor S-(4-nitrobenzyl)-6-thioinosine (NBMPR) demonstrated functional loss of each transporter. Nine nucleoside reverse-transcriptase inhibitors and 37 nucleoside/heterocycle analogs were evaluated to identify ENT interactions. Twenty-one compounds inhibited uridine uptake and abacavir, nevirapine, ticagrelor, and uridine triacetate had different IC50 values for ENT1 and ENT2. Total accumulation of four identified inhibitors was measured with and without NBMPR to determine whether there was ENT-mediated transport. Clofarabine and cladribine were ENT1 and ENT2 substrates, whereas nevirapine and lexibulin were ENT1 and ENT2 nontransported inhibitors. Bayesian models generated using Assay Central machine learning software yielded reasonably high internal validation performance (receiver operator characteristic > 0.7). ENT1 IC50-based models were generated from ChEMBL; subvalidations using this training data set correctly predicted 58% of inhibitors when analyzing activity by percent uptake and 63% when using estimated-IC50 values. Determining drug interactions with these transporters can be useful in identifying and predicting compounds that are ENT1 and ENT2 substrates and can thereby circumvent the BTB through this transepithelial transport pathway in Sertoli cells. SIGNIFICANCE STATEMENT: This study is the first to predict drug interactions with equilibrative nucleoside transporter (ENT) 1 and ENT2 using Bayesian modeling. Novel CRISPR/CRISPR-associated protein 9 functional knockouts of ENT1 and ENT2 in HeLa S3 cells were generated and characterized. Determining drug interactions with these transporters can be useful in identifying and predicting compounds that are ENT1 and ENT2 substrates and can circumvent the blood-testis barrier through this transepithelial transport pathway in Sertoli cells.

Pharmacokinetic and Pharmacodynamic Factors Contribute to Synergism between Let-7c-5p and 5-Fluorouracil in Inhibiting Hepatocellular Carcinoma Cell Viability.

Pharmacological interventions for hepatocellular carcinoma (HCC) are hindered by complex factors, and rational combination therapy may be developed to improve therapeutic outcomes. Very recently, we have identified a bioengineered microRNA let-7c-5p (or let-7c) agent as an effective inhibitor against HCC in vitro and in vivo. In this study, we sought to identify small-molecule drugs that may synergistically act with let-7c against HCC. Interestingly, we found that let-7c exhibited a strong synergism with 5-fluorouracil (5-FU) in the inhibition of HCC cell viability as manifested by average combination indices of 0.3 and 0.5 in Hep3B and Huh7 cells, respectively. By contrast, coadministration of let-7c with doxorubicin or sorafenib inhibited HCC cell viability with, rather surprisingly, no or minimal synergy. Further studies showed that protein levels of multidrug resistance-associated protein (MRP) ATP-binding cassette subfamily C member 5 (MRP5/ABCC5), a 5-FU efflux transporter, were reduced around 50% by let-7c in HCC cells. This led to a greater degree of intracellular accumulation of 5-FU in Huh7 cells as well as the second messenger cyclic adenosine monophosphate, an endogenous substrate of MRP5. Since 5-FU is an irreversible inhibitor of thymidylate synthetase (TS), we investigated the interactions of let-7c with 5-FU at pharmacodynamic level. Interestingly, our data revealed that let-7c significantly reduced TS protein levels in Huh7 cells, which was associated with the suppression of upstream transcriptional factors as well as other regulatory factors. Collectively, these results indicate that let-7c interacts with 5-FU at both pharmacokinetic and pharmacodynamic levels, and these findings shall offer insight into molecular mechanisms of synergistic drug combinations. SIGNIFICANCE STATEMENT: Combination therapy is a common strategy that generally involves pharmacodynamic interactions. After identifying a strong synergism between let-7c-5p and 5-fluorouracil (5-FU) against hepatocellular carcinoma cell viability, we reveal the involvement of both pharmacokinetic and pharmacodynamic mechanisms. In particular, let-7c enhances 5-FU exposure (via suppressing ABCC5/MRP5 expression) and cotargets thymidylate synthase with 5-FU (let-7c reduces protein expression, whereas 5-FU irreversibly inactivates enzyme). These findings provide insight into developing rational combination therapies based on pharmacological mechanisms.

Nucleoside Reverse Transcriptase Inhibitor Interaction with Human Equilibrative Nucleoside Transporters 1 and 2.

Equilibrative nucleoside transporters (ENTs) transport nucleosides across the blood-testis barrier (BTB). ENTs are of interest to study the disposition of nucleoside reverse-transcriptase inhibitors (NRTIs) in the human male genital tract because of their similarity in structure to nucleosides. HeLa S3 cells express ENT1 and ENT2 and were used to compare relative interactions of these transporters with selected NRTIs. Inhibition of [3H]uridine uptake by NBMPR was biphasic, with IC50 values of 11.3 nM for ENT1 and 9.6 µM for ENT2. Uptake measured with 100 nM NBMPR represented ENT2-mediated transport; subtracting that from total uptake represented ENT1-mediated transport. The kinetics of ENT1- and ENT2-mediated [3H]uridine uptake revealed no difference in Jmax (16.53 and 30.40 pmol cm-2 min-1) and an eightfold difference in Kt (13.6 and 108.9 µM). The resulting fivefold difference in intrinsic clearance (Jmax/Kt) for ENT1- and ENT2 transport accounted for observed inhibition of [3H]uridine uptake by 100 nM NBMPR. Millimolar concentrations of the NRTIs emtricitabine, didanosine, lamivudine, stavudine, tenofovir disoproxil, and zalcitabine had no effect on ENT transport activity, whereas abacavir, entecavir, and zidovudine inhibited both transporters with IC50 values of ∼200 µM, 2.5 mM, and 2 mM, respectively. Using liquid chromatography-tandem mass spectrometry and [3H] compounds, the data suggest that entecavir is an ENT substrate, abacavir is an ENT inhibitor, and zidovudine uptake is carrier-mediated, although not an ENT substrate. These data show that HeLa S3 cells can be used to explore complex transporter selectivity and are an adequate model for studying ENTs present at the BTB. SIGNIFICANCE STATEMENT: This study characterizes an in vitro model using S-[(4-nitrophenyl)methyl]-6-thioinosine to differentiate between equilibrative nucleoside transporter (ENT) 1- and ENT2-mediated uridine transport in HeLa cells. This provides a method to assess the influence of nucleoside reverse-transcriptase inhibitors on natively expressed transporter function. Determining substrate selectivity of the ENTs in HeLa cells can be effectively translated into the activity of these transporters in Sertoli cells that comprise the blood-testis barrier, thereby assisting targeted drug development of compounds capable of circumventing the blood-testis barrier.

A reliable LC-MS/MS method for the quantification of natural amino acids in mouse plasma: Method validation and application to a study on amino acid dynamics during hepatocellular carcinoma progression.

A simple and fast LC-MS/MS method was developed and validated for simultaneous quantification of 20 proteinogenic l-amino acids (AAs) in a small volume (5 µL) of mouse plasma. Chromatographic separation was achieved on an Intrada Amino Acid column within 13 min via gradient elution with an aqueous solution containing 100 mM ammonium formate and an organic mobile phase containing acetonitrile, water and formic acid (v:v:v = 95:5:0.3), at the flow rate of 0.6 mL/min. Individual AAs and corresponding stable-isotope-labeled AAs internal standards were analyzed by multiple reaction monitoring (MRM) in positive ion mode under optimized conditions. Method validation consisted of linearity, sensitivity, accuracy and precision, recovery, matrix effect, and stability, and the results demonstrated this LC-MS/MS method as a specific, accurate, and reliable assay. This LC-MS/MS method was thus utilized to compare the dynamics of individual plasma AAs between healthy and orthotopic hepatocellular carcinoma (HCC) xenograft mice housed under identical conditions. Our results revealed that, 5 weeks after HCC tumor progression, plasma l-arginine concentrations were significantly decreased in HCC mice while l-alanine and l-threonine levels were sharply increased. These findings support the utilities of this LC-MS/MS method and the promise of specific AAs as possible biomarkers for HCC.

Bioengineered Let-7c Inhibits Orthotopic Hepatocellular Carcinoma and Improves Overall Survival with Minimal Immunogenicity.

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related deaths, warranting better therapies. Restoration of tumor-suppressive microRNAs depleted in hepatocellular carcinoma represents a new therapeutic strategy. Herein, we sought to identify a potent microRNA (miRNA) agent that could alleviate HCC tumor burden and improve survival. Among a collection of bioengineered noncoding RNA molecules produced through bacterial fermentation, we identified let-7c agent as the most potent inhibitor of HCC cell viability. Bioengineered let-7c selectively modulated target gene expression (Lin-28 homolog B [LIN28B], AT-rich interactive domain-containing protein 3B [ARID3B], B cell lymphoma-extra large [Bcl-xl], and c-Myc) in HCC cells, and consequently induced apoptosis and inhibited tumorsphere growth. When formulated with liposomal-branched polyethylenimine polyplex, bioengineered let-7c exhibited serum stability up to 24 h. Furthermore, liposomal polyplex-formulated let-7c could effectively reduce tumor burden and progression in orthotopic HCC mouse models, while linear polyethyleneimine-formulated let-7c to a lower degree, as revealed by live animal and ex vivo tissue imaging studies. This was also supported by reduced serum α-fetoprotein and bilirubin levels in let-7c-treated mice. In addition, lipopolyplex-formulated let-7c extended overall survival of HCC tumor-bearing mice and elicited no or minimal immune responses in healthy immunocompetent mice and human peripheral blood mononuclear cells. These results demonstrate that bioengineered let-7c is a promising molecule for advanced HCC therapy, and liposomal polyplex is a superior modality for in vivo RNA delivery.

Lipidation of polyethylenimine-based polyplex increases serum stability of bioengineered RNAi agents and offers more consistent tumoral gene knockdown in vivo.

Recently we have established a novel approach to produce bioengineered noncoding RNA agents (BERAs) in living cells that carry target RNAi molecules (e.g., siRNA and miRNA) and thus act as "prodrugs". Using GFP-siRNA-loaded BERA (BERA/GFP-siRNA) as a model molecule, this study was to define the in vitro and in vivo knockdown efficiency of BERAs delivered by liposome-polyethylenimine nanocomplex (lipopolyplex or LPP). Compared to in vivo-jetPEI® (IVJ-PEI) and polyplex formulations, LPP offered greater protection of BERA/GFP-siRNA against degradation by serum RNases. Particle sizes and zeta potentials of LPP nanocomplex remained stable over 28 days when stored at 4 °C. Furthermore, comparable levels of BERA/GFP-siRNA were delivered by LPP and IVJ-PEI to luciferase/GFP-expressing human SK-Hep1-Luc-GFP or A549-Luc-GFP cells, which were selectively processed into target GFP-siRNA and subsequently knocked down GFP mRNA and protein levels. In addition, LPP-carried BERA/GFP-siRNA was successfully delivered into xenograft tumors and offered more consistent knockdown of tumoral GFP mRNA level in an orthotopic hepatocellular carcinoma (HCC) SK-Hep1-Luc-GFP xenograft mouse model, while IVJ-PEI formulation showed larger variation. These findings demonstrated that lipidation of polyplexes improved serum stability of biologic RNAi molecules, which was efficiently delivered to orthotopic HCC tissues to knock down target gene expression.

Bioengineered Noncoding RNAs Selectively Change Cellular miRNome Profiles for Cancer Therapy.

Noncoding RNAs (ncRNAs) produced in live cells may better reflect intracellular ncRNAs for research and therapy. Attempts were made to produce biologic ncRNAs, but at low yield or success rate. Here we first report a new ncRNA bioengineering technology using more stable ncRNA carrier (nCAR) containing a pre-miR-34a derivative identified by rational design and experimental validation. This approach offered a remarkable higher level expression (40%-80% of total RNAs) of recombinant ncRNAs in bacteria and gave an 80% success rate (33 of 42 ncRNAs). New FPLC and spin-column based methods were also developed for large- and small-scale purification of milligrams and micrograms of recombinant ncRNAs from half liter and milliliters of bacterial culture, respectively. We then used two bioengineered nCAR/miRNAs to demonstrate the selective release of target miRNAs into human cells, which were revealed to be Dicer dependent (miR-34a-5p) or independent (miR-124a-3p), and subsequent changes of miRNome and transcriptome profiles. miRNA enrichment analyses of altered transcriptome confirmed the specificity of nCAR/miRNAs in target gene regulation. Furthermore, nCAR assembled miR-34a-5p and miR-124-3p were active in suppressing human lung carcinoma cell proliferation through modulation of target gene expression (e.g., cMET and CDK6 for miR-34a-5p; STAT3 and ABCC4 for miR-124-3p). In addition, bioengineered miRNA molecules were effective in controlling metastatic lung xenograft progression, as demonstrated by live animal and ex vivo lung tissue bioluminescent imaging as well as histopathological examination. This novel ncRNA bioengineering platform can be easily adapted to produce various ncRNA molecules, and biologic ncRNAs hold the promise as new cancer therapeutics.

Bioengineered NRF2-siRNA Is Effective to Interfere with NRF2 Pathways and Improve Chemosensitivity of Human Cancer Cells.

The nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a transcription factor in the regulation of many oxidative enzymes and efflux transporters critical for oxidative stress and cellular defense against xenobiotics. NRF2 is dysregulated in patient osteosarcoma (OS) tissues and correlates with therapeutic outcomes. Nevertheless, research on the NRF2 regulatory pathways and its potential as a therapeutic target is limited to the use of synthetic small interfering RNA (siRNA) carrying extensive artificial modifications. Herein, we report successful high-level expression of recombinant siRNA against NRF2 in Escherichia coli using our newly established noncoding RNA bioengineering technology, which was purified to >99% homogeneity using an anion-exchange fast protein liquid chromatography method. Bioengineered NRF2-siRNA was able to significantly knock down NRF2 mRNA and protein levels in human OS 143B and MG63 cells, and subsequently suppressed the expression of NRF2-regulated oxidative enzymes [heme oxygenase-1 and NAD(P)H:quinone oxidoreductase 1] and elevated intracellular levels of reactive oxygen species. In addition, recombinant NRF2-siRNA was effective to sensitize both 143B and MG63 cells to doxorubicin, cisplatin, and sorafenib, which was associated with significant downregulation of NRF2-targeted ATP-binding cassette (ABC) efflux transporters (ABCC3, ABCC4, and ABCG2). These findings support that targeting NRF2 signaling pathways may improve the sensitivity of cancer cells to chemotherapy, and bioengineered siRNA molecules should be added to current tools for related research.

Effects of MicroRNA-34a on the Pharmacokinetics of Cytochrome P450 Probe Drugs in Mice.

MicroRNAs (miRNAs or miRs), including miR-34a, have been shown to regulate nuclear receptor, drug-metabolizing enzyme, and transporter gene expression in various cell model systems. However, to what degree miRNAs affect pharmacokinetics (PK) at the systemic level remains unknown. In addition, miR-34a replacement therapy represents a new cancer treatment strategy, although it is unknown whether miR-34a therapeutic agents could elicit any drug-drug interactions. To address this question, we refined a practical single-mouse PK approach and investigated the effects of a bioengineered miR-34a agent on the PK of several cytochrome P450 probe drugs (midazolam, dextromethorphan, phenacetin, diclofenac, and chlorzoxazone) administered as a cocktail. This approach involves manual serial blood microsampling from a single mouse and requires a sensitive liquid chromatography-tandem mass spectrometry assay, which was able to illustrate the sharp changes in midazolam PK by ketoconazole and pregnenolone 16α-carbonitrile as well as phenacetin PK by α-naphthoflavone and 3-methylcholanthrene. Surprisingly, 3-methylcholanthrene also decreased systemic exposure to midazolam, whereas both pregnenolone 16α-carbonitrile and 3-methylcholanthrene largely reduced the exposure to dextromethorphan, diclofenac, and chlorzoxazone. Finally, the biologic miR-34a agent had no significant effects on the PK of cocktail drugs but caused a marginal (45%-48%) increase in systemic exposure to midazolam, phenacetin, and dextromethorphan in mice. In vitro validation of these data suggested that miR-34a slightly attenuated intrinsic clearance of dextromethorphan. These findings from single-mouse PK and corresponding mouse liver microsome models suggest that miR-34a might have minor or no effects on the PK of coadministered cytochrome P450-metabolized drugs.

Mono-2-ethylhexyl phthalate disrupts neurulation and modifies the embryonic redox environment and gene expression.

Mono-2-ethylhexl phthalate (MEHP) is the primary metabolite of di-2-ethylhexyl phthalate (DEHP), a ubiquitous contaminant in plastics. This study sought to determine how structural defects caused by MEHP in mouse whole embryo culture were related to temporal and spatial patterns of redox state and gene expression. MEHP reduced morphology scores along with increased incidence of neural tube defects. Glutathione (GSH) and cysteine (Cys) concentrations fluctuated spatially and temporally in embryo (EMB) and visceral yolk sac (VYS) across the 24h culture. Redox potentials (Eh) for GSSG/GSH were increased by MEHP in EMB (12h) but not in VYS. CySS/CyS Eh in EMB and VYS were significantly increased at 3h and 24h, respectively. Gene expression at 6h showed that MEHP induced selective alterations in EMB and VYS for oxidative phosphorylation and energy metabolism pathways. Overall, MEHP affects neurulation, alters Eh, and spatially alters the expression of metabolic genes in the early organogenesis-stage mouse conceptus.

Mono-2-ethylhexyl phthalate (MEHP) alters histiotrophic nutrition pathways and epigenetic processes in the developing conceptus.

Histiotrophic nutrition pathways (HNPs) are processes by which the organogenesis-stage conceptus obtains nutrients, amino acids, vitamins and cofactors required for protein biosynthesis and metabolic activities. Nutrients are captured from the maternal milieu as whole proteins and cargoes via receptor-mediated endocytosis in the visceral yolk sac (VYS), degraded by lysosomal proteolysis and delivered to the developing embryo (EMB). Several nutrients obtained by HNPs are required substrates for one-carbon (C1) metabolism and supply methyl groups required for epigenetic processes, including DNA and histone methylation. Increased availability of methyl donors has been associated with reduced risk for neural tube defects (NTDs). Here, we show that mono-2-ethylhexyl phthalate (MEHP) treatment (100 or 250µM) alters HNPs, C1 metabolism and epigenetic programming in the organogenesis-stage conceptus. Specifically, 3-h MEHP treatment of mouse EMBs in whole culture resulted in dose-dependent reduction of HNP activity in the conceptus. To observe nutrient consequences of decreased HNP function, C1 components and substrates and epigenetic outcomes were quantified at 24h. Treatment with 100-µM MEHP resulted in decreased dietary methyl donor concentrations, while treatment with 100- or 250-µM MEHP resulted in dose-dependent elevated C1 products and substrates. In MEHP-treated EMBs with NTDs, H3K4 methylation was significantly increased, while no effects were seen in treated VYS. DNA methylation was reduced in MEHP-treated EMB with and without NTDs. This research suggests that environmental toxicants such as MEHP decrease embryonic nutrition in a time-dependent manner and that epigenetic consequences of HNP disruption may be exacerbated in EMB with NTDs.

MicroRNA Pharmacoepigenetics: Posttranscriptional Regulation Mechanisms behind Variable Drug Disposition and Strategy to Develop More Effective Therapy.

Knowledge of drug absorption, distribution, metabolism, and excretion (ADME) or pharmacokinetics properties is essential for drug development and safe use of medicine. Varied or altered ADME may lead to a loss of efficacy or adverse drug effects. Understanding the causes of variations in drug disposition and response has proven critical for the practice of personalized or precision medicine. The rise of noncoding microRNA (miRNA) pharmacoepigenetics and pharmacoepigenomics has come with accumulating evidence supporting the role of miRNAs in the modulation of ADME gene expression and then drug disposition and response. In this article, we review the advances in miRNA pharmacoepigenetics including the mechanistic actions of miRNAs in the modulation of Phase I and II drug-metabolizing enzymes, efflux and uptake transporters, and xenobiotic receptors or transcription factors after briefly introducing the characteristics of miRNA-mediated posttranscriptional gene regulation. Consequently, miRNAs may have significant influence on drug disposition and response. Therefore, research on miRNA pharmacoepigenetics shall not only improve mechanistic understanding of variations in pharmacotherapy but also provide novel insights into developing more effective therapeutic strategies.

Amino acid starvation induced by protease inhibition produces differential alterations in redox status and the thiol proteome in organogenesis-stage rat embryos and visceral yolk sacs.

The process of embryonic nutrition in rodent conceptuses during organogenesis has been shown to involve a dominant histiotrophic mechanism where essential developmental substrates and micronutrients are supplied as whole maternal proteins or cargoes associated with proteins. The histiotrophic nutrition pathways (HNP) responsible for uptake and initial processing of proteins across maternal-conceptal interfaces involve uptake via receptor mediated endocytosis and protein degradation via lysosomal proteolysis. Chemical inhibition of either process can lead to growth deficits and malformation in the embryo (EMB), but selective inhibition of either HNP component will elicit a different subset of developmental perturbations. In vitro, whole embryo culture exposure of GD10 or GD11 rat conceptuses to the natural protease inhibitor, leupeptin, leads to significant reductions in all measured embryonic growth parameters as well as a myriad of other effects. Leupeptin doses of 10 µM or 20 µM over a 26-h period (GD10-GD11) and 50 µM over a 3 h pulse period produced significant decreases in the clearance of FITC-albumin from culture media. The near complete loss of acid soluble fluorescence and increased total visceral yolk sac (VYS) protein content confirmed the selective inhibition of proteolysis. Inhibition of lysosomal proteolysis thus deprives the developing EMB of essential nutrient amino acids producing conditions akin to amino acid starvation, but may also cause direct effects on pathways critical for normal growth and differentiation. Following leupeptin exposure for 26 or 6 h, total glutathione (GSH) concentrations dropped significantly in the VYS, but only slightly in yolk sac (YSF) and amniotic (AF) fluids. Cys concentrations increased in VYS and EMB, but dropped in YSF and AF fluids. Redox potentials (Eh) for the glutathione disulfide (GSSG)/glutathione (GSH) redox couple trended significantly toward the positive, confirming the net oxidation of conceptual tissues following leupeptin treatment. Analysis of the thiol proteome showed few alterations to specific pathways mapped to the Kyoto Encyclopedia of Genes and Genomes Pathway database, but did reveal significant increases in concentrations of proteins associated with glycolysis/gluconeogenesis in the VYS and decreased concentrations proteins associated with ribosome biogenesis and function in the EMB. A subset of proteins elevated by >2-23-fold in the VYS were identified as serum (blood) proteins and represent the maternal-side proteins captured by the VYS and which are not degraded in the lysosomes as a result of leupeptin's inhibitory action. The observed constellation of proteins decreased in the EMB by leupeptin represent proteins from several adaptive pathways that are commonly altered in responses to amino acid starvation. These studies show clear differential responses to protease inhibition in VYS and EMB during organogenesis and suggest the possibility for additional roles of redox regulation, cellular adaptations and metabolic insufficiency caused by protease inhibition.