Unraveling the interconversion pharmacokinetics and oral bioavailability of the major ginger constituents: [6]-gingerol, [6]-shogaol, and zingerone after single-dose administration in rats.

Background: The available in vitro evidences suggest the inherent instability and interconvertibility of [6]-gingerol and [6]-shogaol. However, limited data on their in vivo interconversion hinder understanding of their influence on the pharmacokinetic profiles. Purpose: This study presents the first comprehensive in vivo investigation aiming to determine the interconversion pharmacokinetics in rats, and elucidate the oral bioavailability, target distribution, biotransformation, and excretion profiles of the key ginger constituents, [6]-gingerol, [6]-shogaol, and zingerone. Methods: The pharmacokinetics was investigated through single intravenous (3 mg/kg) or oral (30 mg/kg) administration of [6]-gingerol, [6]-shogaol, or zingerone, followed by the determination of their tissue distribution after oral dosing (30 mg/kg). Intravenous pharmacokinetics was leveraged to evaluate the interconversion, circumventing potential confounders associated with the oral route. Results: All rats tolerated these compounds throughout the pharmacokinetic study. The parent compounds exhibited rapid but partial absorption, and extensive organ distribution with substantial biotransformation, thereby limiting the oral bioavailability of each compound to below 2% when administered as pure compounds. Conversion of [6]-gingerol to [6]-shogaol after intravenous administration, demonstrated a significantly larger clearance compared to the reverse conversion ([6]-shogaol to [6]-gingerol). The irreversible metabolic clearance for both compounds was significantly greater than their reversible bioconversions. Furthermore, [6]-gingerol underwent biotransformation to zingerone. Conjugated glucuronides were eliminated partly through renal excretion, with minimal fecal excretion. Conclusion: This in vivo investigation demonstrates the influence of interconversion on the disposition kinetics of [6]-gingerol, [6]-shogaol, and zingerone, as evidenced by the findings in the systemic circulation. The study further highlights the importance of considering this interconversion and tissue distribution when determining the administration dosage of ginger constituent combinations for therapeutic benefits and clinical applications.

Identification of Molecular Mechanisms of Ameloblastoma and Drug Repositioning by Integration of Bioinformatics Analysis and Molecular Docking Simulation.

Background: Ameloblastoma (AM) is a benign tumor locally originated from odontogenic epithelium that is commonly found in the jaw. This tumor makes aggressive invasions and has a high recurrence rate. This study aimed to investigate the differentially expressed genes (DEGs), biological function alterations, disease targets, and existing drugs for AM using bioinformatics analysis. Methods: The data set of AM was retrieved from the GEO database (GSE132474) and identified the DEGs using bioinformatics analysis. The biological alteration analysis was applied to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Protein-protein interaction (PPI) network analysis and hub gene identification were screened through NetworkAnalyst. The transcription factor-protein network was constructed via OmicsNet. We also identified candidate compounds from L1000CDS2 database. The target of AM and candidate compounds were verified using docking simulation. Results: Totally, 611 DEGs were identified. The biological function enrichment analysis revealed glycosaminoglycan and GABA (γ-aminobutyric acid) signaling were most significantly up-regulated and down-regulated in AM, respectively. Subsequently, hub genes and transcription factors were screened via the network and showed FOS protein was found in both networks. Furthermore, we evaluated FOS protein to be a therapeutic target in AMs. Candidate compounds were screened and verified using docking simulation. Tanespimycin showed the greatest affinity binding value to bind FOS protein. Conclusions: This study presented the underlying molecular mechanisms of disease pathogenesis, biological alteration, and important pathways of AMs and provided a candidate compound, Tanespimycin, targeting FOS protein for the treatment of AMs.

Comparison of diterpenoid contents and dissolution profiles of selected Andrographis paniculata crude and extract capsules.

INTRODUCTION: Andrographis paniculata (AP) has been approved by the Thai government for the treatment of mild cases of COVID-19 patients. Increasing use of AP products requires quality control to ensure efficacy and safety. At present, there is no requirement for dissolution test of AP products in the Thai Herbal Pharmacopoeia (THP). OBJECTIVE: This work aimed to examine the contents and dissolution profiles of active diterpenoids, andrographolide (AP1), 14-deoxy-11,12-didehydroandrographolide (AP3), neoandrographolide (AP4), and 14-deoxyandrographolide (AP6) in AP capsules available in Thai markets. MATERIALS AND METHODS: Four extract products (EXT. A-D) and three crude powder products (CRD. A-C) were tested for contents by using HPLC-DAD. Dissolution profiles of four diterpenoids were investigated in different media (pH 1.2, 4.5, 6.8, and 0.01 N HCl + SLS) with apparatus II (paddle type). RESULTS: The AP1 contents were 1.99%-2.90% w/w for crude capsules and 2.84%-16.27% w/w for extract capsules. In the dissolution test, the dissolution percentages of four diterpenoids from crude capsules were higher than those from extract capsules except EXT. A. AP1 in most extract products (EXT. B, C, D) was dissolved in all dissolution media at a lower percentage than the other three diterpenoids. EXT. A (aqueous extract) was the only extract capsule showing the amounts of all diterpenoids dissolved in all media >80% in 45 min. CONCLUSION: The study demonstrated that AP1 content in AP products complied with the acceptance criteria in the THP (80%-120%), and the weight variation also met the United States Pharmacopeia (USP) requirements. However, different dissolution profiles of AP products may lead to different bioavailability of diterpenoids and further affect their efficacy.

Arsenic-induced IGF-1 signaling impairment and neurite shortening: The protective roles of IGF-1 through the PI3K/Akt axis.

We recently reported that arsenic caused insulin resistance in differentiated human neuroblastoma SH-SY5Y cells. Herein, we further investigated the effects of sodium arsenite on IGF-1 signaling, which shares downstream signaling with insulin. A time-course experiment revealed that sodium arsenite began to decrease IGF-1-stimulated Akt phosphorylation on Day 3 after treatment, indicating that prolonged sodium arsenite treatment disrupted the neuronal IGF-1 response. Additionally, sodium arsenite decreased IGF-1-stimulated tyrosine phosphorylation of the IGF-1 receptor ß (IGF-1Rß) and its downstream target, insulin receptor substrate 1 (IRS1). These results suggested that sodium arsenite impaired the intrinsic tyrosine kinase activity of IGF-1Rß, ultimately resulting in a reduction in tyrosine-phosphorylated IRS1. Sodium arsenite also reduced IGF-1 stimulated tyrosine phosphorylation of insulin receptor ß (IRß), indicating the potential inhibition of IGF-1R/IR crosstalk by sodium arsenite. Interestingly, sodium arsenite also induced neurite shortening at the same concentrations that caused IGF-1 signaling impairment. A 24-h IGF-1 treatment partially rescued neurite shortening caused by sodium arsenite. Moreover, the reduction in Akt phosphorylation by sodium arsenite was attenuated by IGF-1. Inhibition of PI3K/Akt by LY294002 diminished the protective effects of IGF-1 against sodium arsenite-induced neurite retraction. Together, our findings suggested that sodium arsenite-impaired IGF-1 signaling, leading to neurite shortening through IGF-1/PI3K/Akt.

Method Validation for Quantification of PFOS and PFOA in Human Plasma and a Pilot Study in Blood Donors from Thai Red Cross Society.

Information regarding per- and polyfluorinated substances concentrations in biological samples from the Thai population was still lacking. A sensitive bioanalytical method was developed and validated for the quantification of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) levels in human plasma. Simple protein precipitation and LC-MS/MS techniques were used with stable isotope internal standards of 13C8-PFOS and 13C8-PFOA. The validated method followed the ICH bioanalytical validation guideline, and the results showed good accuracy, precision, and reproducibility. The validated analytical method was then applied to determine PFOS and PFOA concentrations in 50 human plasma samples from the National Blood Center, Thai Red Cross Society. The concentrations were found to be in ranges of <0.91-6.27 ng/mL for PFOS and <0.49-2.72 ng/mL for PFOA. PFOS was also measured separately for its isomers, and the geometric means of the linear isomer (L-PFOS) and branched isomer (br-PFOS) in plasma samples were at 1.85 and 0.41 ng/mL, respectively. Both PFOS and PFOA concentrations were lower in comparison to previous reports from other countries. The present study showed the application of our reliable method to determine PFOS and PFOA in biological samples in order to monitor the human exposure of both chemicals in Thailand.

Integrated Transcriptomics and Network Analysis Identified Altered Neural Mechanisms in Frontal Aging Brain-Associated Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease. The late stage of AD typically develops after 60 years of age and AD pathogenesis can be detected predominately in the frontal lobe, which is responsible for memory. Multiple alterations in cellular mechanisms have been associated with AD, but there is no clear information on AD pathogenesis during brain aging. This study aimed to explore the differentially expressed genes (DEGs) in the frontal lobe of aging brains and to identify shared crucial mechanisms in the aging brain linked to AD pathogenesis. Three datasets were downloaded from the Gene Expression Omnibus (GEO). Biological function analysis was performed by DAVID and KEGG databases. An AD patient's cohort (GSE150696) was collected for verification of the enriched pathway. The results demonstrated that multiple neurochemical synapsis and regulation of the cytoskeleton are linked to AD pathogenesis during aging. Taken together, this study contributes to our further understanding of neural alterations during aging in AD that could be used to develop therapeutics for early intervention to prevent or slow progression.

8-Chloroadenosine Induces ER Stress and Apoptotic Cell Death in Cholangiocarcinoma Cells.

BACKGROUND/AIM: Cholangiocarcinoma is a lethal cancer, and current chemotherapeutic drugs are not very effective. Recent studies reported that cholangiocarcinoma cells were sensitive to adenosine. One adenosine analog, 8-chloroadenosine (8-CA), was shown to be more potent than adenosine and induced apoptosis in leukemia cells. This study examined effects of 8-CA in cholangiocarcinoma cells and immortalized cholangiocytes. MATERIALS AND METHODS: Cell growth was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell invasion was examined by transwell assay. Cell cycle and cell death were evaluated by flow cytometry. Colorimetric absorbance assay was used to assessed RNA and protein synthesis as well as mitochondrial membrane potential. Protein levels were examined by western blot analysis. Animal experiment was performed in Balb/cAJcl-Nu mice. RESULTS: 8-CA reduced cholangiocarcinoma cell growth, prevented colony formation and caused endoplasmic reticulum stress and cell-cycle arrest. Eventually, apoptosis was induced. However, treatment with 8-CA did not interfere with RNA synthesis or protein synthesis and did not alter mitochondrial membrane potential. Combination of 8-CA with several chemotherapeutic drugs in vitro was less effective than 8-CA alone and the drugs alone, except for the combination of 8-CA with hydroxychloroquine, which had an additive effect on RMCCA-1 cells. However, further in vivo study showed that treatment with 8-CA alone inhibited tumor growth more than treatment with a combination of 8-CA with hydroxychloroquine. CONCLUSION: 8-Chloroadenosine inhibited CCA cells by inducing endoplasmic reticulum stress and apoptosis. In vivo study showed that 8-CA inhibited cholangiocarcinoma tumor growth better when administered alone as compared to a combination with hydroxychloroquine.

Integrated Transcriptomics and Network Analysis of Potential Mechanisms and Health Effects of Convalescent COVID-19 Patients.

Coronaviral disease 2019 (COVID-19) is a recent pandemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, there are still cases of COVID-19 around the world that can develop into persistent symptoms after discharge. The constellation of symptoms, termed long COVID, persists for months and can lead to various diseases such as lung inflammation and cardiovascular disease, which may lead to considerable financial burden and possible risk to human health. Moreover, the molecular mechanisms underlying the post-pandemic syndrome of COVID-19 remain unclear. In this study, we aimed to explore the molecular mechanism, disease association, and possible health risks in convalescent COVID-19 patients. Gene expression data from a human convalescent COVID-19 data set was compared with a data set from healthy normal individuals in order to identify differentially expressed genes (DEGs). To determine biological function and potential pathway alterations, the GO and KEGG databases were used to analyze the DEGs. Disease association, tissue, and organ-specific analyses were used to identify possible health effects. A total of 250 DEGs were identified between healthy and convalescent COVID-19 subjects. The biological function alterations identified revealed cytokine interactions and increased inflammation through NF-κB1, RELA, JUN, STAT3, and SP1. Interestingly, the most significant pathways were cytokine-cytokine receptor interaction, altered lipid metabolism, and atherosclerosis that play a crucial role in convalescent COVID-19. In addition, we also found pneumonitis, dermatitis, and autoimmune diseases. Based on our study, convalescent COVID-19 is associated with inflammation in a variety of organs that could lead to autoimmune and inflammatory diseases, as well as atherosclerosis. These findings are a first step toward fully exploring the disease mechanisms in depth to understand the relationship between post-COVID-19 infection and potential health risks. This is necessary for the development of appropriate strategies for the prevention and treatment of long COVID.

Comparative pharmacokinetics and safety evaluation of high dosage regimens of Andrographis paniculata aqueous extract after single and multiple oral administration in healthy participants.

Background: The prolonged situation of the COVID-19 pandemic, with the emergence of new variants of SARS-CoV-2, not only imposes a financial burden on healthcare supports but also contributes to the issue of medication shortages, particularly in countries with limited access to medical resources or developing countries. To provide an alternative therapeutic approach during this crisis, there is an increasing research that has investigated the potential uses of Andrographis paniculata in supporting the application of herbal medicine for COVID-19. Purpose: This study aimed to investigate the safety profiles and clinical pharmacokinetics, specifically focusing on dose proportionality of the four major active diterpenoids of Andrographis paniculata aqueous extract following oral administration of two different high doses of andrographolide. Methods: The participants received the aqueous extract capsules equivalent to 60 or 120 mg of andrographolide; and as multiple doses administered three times daily, calculated as 180 or 360 mg/day of andrographolide. Safety evaluation was assessed following the oral administration of the multiple doses. Results: The results indicated a dose-dependent effect observed between the respective two doses. A twofold increase in the dose of the extract demonstrated twofold higher plasma concentrations of the four major parent compounds; 1) andrographolide, 2) 14-deoxy-11, 12-didehydroandrographolide, 3) neoandrographolide, and 4) 14-deoxyandrographolide, as well as their conjugated metabolites. The observed diterpenoids are biotransformed partly through a phase II metabolic pathway of conjugation, thus reducing in the parent compounds in the plasma and existing the majority as conjugated metabolites. These metabolites are then excreted through the hepatobiliary system and urinary elimination. For the results of the safety evaluation, the occasional adverse events experienced by individuals were of mild intensity, infrequent in occurrence, and reversible to the normal baseline. Safety consideration should be given to the individual patient's pertinent health conditions when using this extract in patients with hepatic or kidney dysfunction. Clinical Trial Registration: https://www.thaiclinicaltrials.org/show/TCTR20210201005; Identifier: TCTR20210201005.

Identification of Potential Molecular Mechanisms and Prognostic Markers for Oral Squamous Cell Carcinoma: A Bioinformatics Analysis.

Aims and Objectives: The goal of this study was to uncover crucial biochemical pathways, prognostic indicators, and therapeutic targets in patients with oral cancer in order to enhance therapy strategies. Materials and Methods: Five gene expression omnibus datasets were analyzed by using bioinformatics approaches to identify differentially expressed genes (DEGs). To determine biological alterations, gene ontology (GO) and KEGG pathway analyses were implied using the identified DEGs. Hub genes were determined using protein-protein interaction (PPI) network analysis and an interactome was constructed using NetworkAnalyst. Furthermore, five hub genes were evaluated for use as prognostic markers by using the human protein atlas (HPA) and the GEPIA2.0 database. In addition, the correlations between hub-gene expression and immune cell infiltration of oral squamous cell carcinoma (OSCC) tumors were analyzed using the tWumor immune estimation resource (TIMER) database. Results: A total of 2071 upregulated genes and 1893 downregulated genes were identified. GO and pathway analysis showed DEGs were enriched in multiple immune response terms and interaction of inflammatory cytokines. From the PPI network, five hub genes were identified that have a crucial role in OSCC. These included interferon regulatory factor 4 (IRF4), chemokine receptor 7 (CCR7), TNF receptor superfamily member 17 (TNFRSF17), CD27, and sphingosine-1-phosphate receptor 4 (S1PR4), which were predicted to be favorable prognostic markers for OSCC using HPA. Overall survival analysis revealed that low expression of the five hub genes was significantly associated with worse overall survival. Our analysis of tumor-associated immune infiltration revealed that increased IRF4 expression was positively correlated with the gene expression profiles suggestive of infiltration of all immune cell types, whereas increased CCR7 expression was negatively correlated with neutrophil infiltration. Increased expression of CD27, S1PR4, and TNFRSF17 was found to be negatively correlated with dendritic cell, M0 macrophage, and neutrophil infiltration. Conclusion: In summary, inflammation, and the immune response play an important role in OSCC. All five hub genes were good predictors of OSCC prognosis, suggesting that they could be used as potential therapeutic targets and tumor markers.

Arsenic induces the global hypophosphorylation of insulin receptor substrate proteins in differentiated human neuroblastoma SH-SY5Y cells.

We recently reported that arsenic disrupted neuronal insulin signaling. Here, we further investigated the effect of arsenic on insulin receptor substrate (IRS) proteins, which are crucial downstream signaling molecules of insulin in differentiated human neuroblastoma SH-SY5Y cells. We also found that prolonged arsenic treatment accelerated the migration of IRS1 and IRS2 on SDS-PAGE. Treatment with phosphatases abolished the arsenic-induced increased mobility of IRS, suggesting that the electrophoretic mobility shift of IRS on SDS-PAGE by arsenic was phosphorylation-dependent. By using label-free mass spectrometry, the phosphorylation sites of IRS1 were found to be S24, S345, S636, T774, S1057, S1058, and S1070, while those of IRS2 were at S645, Y653, T657, S665, S667, S669, S672, S915, and S1203, which were at least 2-fold lower than found in the control. These findings indicated a global hypophosphorylation of IRS proteins after prolonged arsenic treatment. In addition, four novel phosphorylation sites were identified on IRS1 (T774, S1057, S1058, and S1070), with another two on IRS2 (S665 and S667). As basal IRS phosphorylation plays an important role in insulin signaling, the reduction of IRS phosphorylation on multiple residues may underlie arsenic-impaired insulin signaling in neurons.

Potentiation of TRAIL-Induced Apoptosis in TRAIL-Resistant Cholangiocarcinoma Cells by Curcumin through the Induction of DR5 Membrane Localization and Disruption of the Anti-Apoptotic Complex DR5/DDX3/GSK3ß.

OBJECTIVE: Cholangiocarcinoma (CCA) is a cancer of the bile duct with a poor prognosis. The present study examined the ability of curcumin to sensitize apoptosis in the TNF-related apoptosis-inducing ligand (TRAIL)-resistant CCA cell lines of HuCCA-1 and KKU-213A. METHODS: Apoptosis was measured using a TUNEL assay. Protein expression was determined by immunoblotting. Membrane death receptor 5 (DR5) was detected by flow cytometry. Protein complex was examined by co-immunoprecipitation. RESULT: Curcumin potentiated TRAIL-induced apoptosis in both cell lines, indicating the sensitization to TRAIL-induced apoptosis by curcumin. Additionally, curcumin increased DR5 expression and membrane localization; however, the curcumin/TRAIL combination did not result in further increases in DR5 expression and membrane localization in either cell line. Moreover, the curcumin/TRAIL combination reduced DR5/decoy receptor 2 (DcR2) complexes in both cell lines, suggesting that curcumin may enhance TRAIL-induced apoptosis by disrupting DR5/DcR2 interaction. In addition, levels of the anti-apoptotic complex DR5/ DDX3/GSK3ß were reduced by the curcumin/TRAIL combination in HuCCA-1 but not in KKU-213A cells. This study also demonstrated that the DR5/DcR2 and DR5/DDX3/GSK3ß complexes could be observed under basal conditions, suggesting that these anti-apoptotic complexes may contribute to TRAIL-resistant phenotypes in both cell lines. Pretreatment with the antioxidant N-acetylcysteine attenuated curcumin-enhanced apoptosis by TRAIL, indicating that curcumin sensitized TRAIL-induced apoptosis through an oxidative stress-dependent mechanism. CONCLUSION: The present study demonstrates the potential of using curcumin in combination with TRAIL to yield better TRAIL therapy outcomes in TRAIL-resistant CCA.

A validated LC-MS/MS method for clinical pharmacokinetics and presumptive phase II metabolic pathways following oral administration of Andrographis paniculata extract.

Andrographis paniculata, a medicinal plant in Thailand national list of essential medicines, has been proposed for treatment of patients with mild to moderate coronavirus disease 2019. This study aims to develop a highly selective and sensitive liquid chromatography triple quadrupole tandem mass spectrometry method for quantitative determination of major diterpenoids in plasma and urine with application in pharmacokinetics. Chromatographic separation was performed on C18 column using a gradient mobile phase of water and acetonitrile. Mass spectrometry was analyzed using multiple reaction monitoring with negative ionization mode. This validated analytical method was very sensitive, less time consuming in analysis, and allowed the reliability and reproducibility on its application. The clinical pharmacokinetics was evaluated after single oral administration of A. paniculata extract (calculated as 60 mg of andrographolide). The disposition kinetics demonstrated that major diterpenoids could enter into systemic circulation, but they are mostly biotransformed (phase II) into conjugated glucuronide and sulfate metabolites. These metabolites are predominantly found in plasma and then extremely eliminated, in part through urinary excretion. The successful application of this analytical method supports its suitable uses in further clinical benefits after oral administration of A. paniculata.

A comprehensive review on disposition kinetics and dosage of oral administration of Andrographis paniculata, an alternative herbal medicine, in co-treatment of coronavirus disease.

Coronavirus disease 2019 (COVID-19) is a present global health crisis that is driving the investigation of alternative phytomedicines for antiviral purposes. The evidence suggests that Andrographis paniculata crude or extract is a promising candidate for treating symptoms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This review aims to consolidate the available reports on the disposition kinetics of andrographolide, a main active component of A. paniculata. The second objective of this review is to summarize the available reports on an appropriate oral dosage for the use of andrographolide in upper respiratory tract infections (URTIs) and other viral infectious diseases. The data were collected from the literature on absorption, distribution, biotransformation, and excretion of andrographolide, and information was also obtained from scientific databases about the use of A. paniculata. The finding of this review on pharmacokinetics indicates that andrographolide is slightly absorbed into the blood circulation and exhibits poor oral bioavailability, whereas its distribution process is unrestricted. In the termination phase, andrographolide preferentially undergoes biotransformation partly through phase I hydroxylation and phase II conjugation, and it is then eliminated via the renal excretion and hepatobiliary system. The key summary of the recommended dosage for andrographolide in uncomplicated URTI treatment is 30 mg/day for children and 60 mg/day for adults. The dose for adult patients with pharyngotonsillitis could be increased to 180 mg/day, but not exceed 360 mg/day. Co-treatment with A. paniculata in concert with the standard supportive care for influenza reduced the severity of symptoms, shortened treatment duration, and decreased the risk of developing post-influenza complications. The recommended starting dose for use in patients with mild COVID-19 is 180 mg/day of andrographolide, based on the dose used in patients experiencing a URTI with inflammation. This review is not only applicable for evaluating the appropriate doses of andrographolide for antiviral treatments but also encourages future research evaluating the effectiveness of these recommended dosages during the COVID-19 pandemic.

The 28-day repeated arsenic exposure increases tau phosphorylation in the rat brain.

Herein, we examined whether prolonged arsenic exposure altered tau phosphorylation in the brain of Sprague Dawley rats expressing endogenous wild-type tau. The results showed that daily intraperitoneal injections of 2.5 mg/kg BW sodium arsenite over 28 days caused arsenic accumulation in the rat brain. Interestingly, we found an increase in tau phosphorylation at the Tau 1 region (189-207) and S202 in the hippocampus, S404 in the cerebral cortex, and S396 and S404 in the cerebellum of arsenic-treated rats. Additionally, arsenic increased active ERK1/2 phosphorylation at T202/Y204 in the hippocampus, cerebral cortex, and cerebellum. Meanwhile, we detected increasing active JNK phosphorylation at T183/Y185 in the hippocampus and cerebellum. Moreover, p35, a neuron-specific activator of CDK5, was also elevated in the cerebellum of arsenic-treated rats, suggesting that CDK5 activity may be increased by arsenic. These results suggested that arsenic may induce tau phosphorylation through the activation of tau kinases, ERK1/2, JNK, and CDK5. Together, the findings from this study demonstrated that prolonged arsenic exposure is implicated in neurodegeneration by promoting tau phosphorylation in the rat brain and points toward a possible prevention strategy against neurodegeneration induced by environmental arsenic exposure.

Prediction of the structural interface between fibroblast growth factor23 and Burosumab using alanine scanning and molecular docking.

Burosumab, an FGF23 targeting monoclonal antibody, was approved by the FDA in 2018 for use in children and adults with X-linked hypophosphatemia (or XLH). While several clinical studies have demonstrated the long-term safety and efficacy of Burosumab, the molecular basis of FGF23-Burosumab interaction which underpins its mechanism of action remains unknown. In this study, we employed molecular docking combined with alanine scanning of epitope and paratope to predict a model of FGF23-Burosumab interaction. Then, we used the model to understand the species-species cross-reactivity of Burosumab and to reverse engineer mouse FGF23 with 'back to human' mutations to bind Burosumab. Finally, we redesigned the CDRs with two mutations to engineer an affinity enhanced variant of the antibody. Our study provides insights into the FGF23-Burosumab interaction and demonstrates that alanine-scanning coupled with molecular docking can be used to optimize antibody candidates (e.g., structure-guided affinity maturation) for therapeutic use.

Characterisation of the triclosan efflux pump TriABC and its regulator TriR in Agrobacterium tumefaciens C58.

TriR serves as a repressor for a resistance-nodulation-cell division (RND) efflux pump TriABC involved in triclosan (TCS) resistance in Agrobacterium tumefaciens. The triR gene is transcribed divergently from the triABC operon. TriR specifically bound to the triR-triA intergenic region, at an imperfect 10 bp inverted repeat, 5'-TTGACTAttC-GgtTAGTCAA-3' (TriR box), that was revealed by DNase I footprinting and electrophoretic mobility shift assay. TCS treatment appeared to up-regulate triR and triABC expression, via preventing TriR binding to the triR-triA intergenic region. Promoter-lacZ fusions and ß-galactosidase activity assay further demonstrated TriR-mediated repression of triABC and triR autoregulation. Site-directed mutagenesis confirmed the identified TriR box is essential for TriR repression. A. tumefaciens mutant strains disrupting either triR or triA were constructed to determine their biological functions. The triA mutant showed hypersensitivity to TCS and sodium dodecyl sulfate (SDS), whereas the triR mutant was hyper-resistant, compared to wild-type. In addition to TCS and SDS, overproduction of TriABC from a multi-copy plasmid conferred enhanced resistance to a quaternary ammonium compound, benzalkonium chloride. Molecular modelling was able to predict the model of TriR and docking simulations were able to anticipate plausible binding interactions between TriR and TCS ligand.

Correction: Lertsuwan et al. CX-4945 Induces Methuosis in Cholangiocarcinoma Cell Lines by a CK2-Independent Mechanism. Cancers 2018, 10, 283.

Authors would like to make a correction to the previous article [...].

Generation of bispecific antibodies by structure-guided redesign of IgG constant regions.

Bispecific antibodies (BsAbs) form an exciting class of bio-therapeutics owing to their multispecificity. Although numerous formats have been developed, generation of hetero-tetrameric IgG1-like BsAbs having acceptable safety and pharmacokinetics profiles from a single cell culture system remains challenging due to the heterogeneous pairing between the four chains. Herein, we employed a structure-guided approach to engineer mutations in the constant domain interfaces (CH1-CL and CH3-CH3) of heavy and κ light chains to prevent heavy-light mispairing in the antigen binding fragment (Fab) region and heavy-heavy homodimerization in the Fc region. Transient co-transfection of mammalian cells with heavy and light chains of pre-existing antibodies carrying the engineered constant domains generates BsAbs with percentage purity ranging from 78% to 85%. The engineered BsAbs demonstrate simultaneous binding of both antigens, while retaining the thermal stability, Fc-mediated effector properties and FcRn binding properties of the parental antibodies. Importantly, since the variable domains were not modified, the mutations may enable BsAb formation from antibodies belonging to different germline origins and isotypes. The rationally designed mutations reported in this work could serve as a starting point for generating optimized solutions required for large scale production.

Sequence of CX-4945 and Cisplatin Administration Determines the Effectiveness of Drug Combination and Cellular Response in Cholangiocarcinoma Cells In Vitro.

BACKGROUND: The incidence of cholangiocarcinoma (CCA) is increasing worldwide and current single chemotherapeutic drug treatments are ineffective. CX-4945 and cisplatin are currently in clinical trial for CCA treatment. MATERIALS AND METHODS: We assessed the effects of the sequence of administration of CX-4945 and cisplatin applied in combination treatments on their efficacy in CCA cells in vitro. CCA cell viability was examined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Apoptosis was examined using flow cytometry. The percentage of cells positive for phosphorylated H2A histone family member X (γ-H2AX) were measured using both flow cytometry and immunofluorescence. RESULTS: CCA cell viability was reduced to 50% after 24 h of treatments with CX-4945 and cisplatin as single agents. Interestingly, treatment with cisplatin 6 h prior to CX-4945 treatment induced significantly more DNA damage and apoptosis than CX-4945 treatment followed by cisplatin. Unexpectedly, CX-4945 treatment followed by cisplatin was less effective than single treatment in RMCCA-1 CCA cells. In addition, a 1:1 ratio of each drug was the most effective combination in these cells. CONCLUSION: These data demonstrate that the combination of CX-4945 and cis platin acts additively when cisplatin is applied first, at least in part due to increased DNA damage and apoptosis. Furthermore, treatment with CX-4945 prior to cisplatin treatment reduces the efficacy of this drug combination in CCA cells.