Biophysical Electrical and Mechanical Stimulations for Promoting Chondrogenesis of Stem Cells on PEDOT:PSS Conductive Polymer Scaffolds.

The investigation of the effects of electrical and mechanical stimulations on chondrogenesis in tissue engineering scaffolds is essential for realizing successful cartilage repair and regeneration. The aim of articular cartilage tissue engineering is to enhance the function of damaged or diseased articular cartilage, which has limited regenerative capacity. Studies have shown that electrical stimulation (ES) promotes mesenchymal stem cell (MSC) chondrogenesis, while mechanical stimulation (MS) enhances the chondrogenic differentiation capacity of MSCs. Therefore, understanding the impact of these stimuli on chondrogenesis is crucial for researchers to develop more effective tissue engineering strategies for cartilage repair and regeneration. This study focuses on the preparation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive polymer (CP) scaffolds using the freeze-drying method. The scaffolds were fabricated with varying concentrations (0, 1, 3, and 10 wt %) of (3-glycidyloxypropyl) trimethoxysilane (GOPS) as a crosslinker and an additive to tailor the scaffold properties. To gain a comprehensive understanding of the material characteristics and the phase aggregation phenomenon of PEDOT:PSS scaffolds, the researchers performed theoretical calculations of solubility parameters and surface energies of PSS, PSS-GOPS, and PEDOT polymers, as well as conducted material analyses. Additionally, the study investigated the potential of promoting chondrogenic differentiation of human adipose stem cells by applying external ES or MS on a PEDOT:PSS CP scaffold. Compared to the group without stimulation, the group that underwent stimulation exhibited significantly up-regulated expression levels of chondrogenic characteristic genes, such as SOX9 and COL2A1. Moreover, the immunofluorescence staining images exhibited a more vigorous fluorescence intensity of SOX9 and COL II proteins that was consistent with the trend of the gene expression results. In the MS experiment, the strain excitation exerted on the scaffold was simulated and transformed into stress. The simulated stress response showed that the peak gradually decreased with time and approached a constant value, with the negative value of stress representing the generation of tensile stress. This stress response quantification could aid researchers in determining specific MS conditions for various materials in tissue engineering, and the applied stress conditions could be further optimized. Overall, these findings are significant contributions to future research on cartilage repair and biophysical ES/MS in tissue engineering.

Defective Interfering Particles with Broad-Acting Antiviral Activity for Dengue, Zika, Yellow Fever, Respiratory Syncytial and SARS-CoV-2 Virus Infection.

More than 100 arboviruses, almost all of which have an RNA genome, cause disease in humans. RNA viruses are causing unprecedented health system challenges worldwide, many with little or no specific therapies or vaccines available. Certain species of mosquito can carry dengue virus (DENV), Zika virus (ZIKV) and yellow fever virus (YFV), where co-infection of these viruses has occurred. Here, we found that purified synthetic defective interfering particles (DIPs) derived from DENV type 2 (DENV-2) strongly suppressed replication of the aforementioned viruses, respiratory syncytial virus (RSV) and also the novel emerging virus SARS-CoV-2 in human cells. DENV DIPs produced in bioreactors, purified by column chromatography, and concentrated are virus-like particles that are about half the diameter of a typical DENV particle, but with similar ratios of the viral structural proteins envelope and capsid. Overall, DIP-treated cells inhibited DENV, ZIKV, YFV, RSV, and SARS-CoV-2 by at least 98% by mechanisms which included interferon (IFN)-dependent cellular antiviral responses. IMPORTANCE DIPs are spontaneously derived virus mutants with deletions in genes that block viral replication. DIPs play important roles in modulation of viral disease, innate immune responses, virus persistence and virus evolution. Here, we investigated the antiviral activity of highly purified synthetic DIPs derived from DENV, which were produced in bioreactors. DENV DIPs purified by column chromatography strongly inhibited five different RNA viruses, including DENV, ZIKV, YFV, RSV, and SARS-CoV-2 in human cells. DENV DIPs inhibited virus replication via delivery of a small, noninfectious viral RNA that activated cellular innate immunity, resulting in robust type 1 interferon responses. The work here presents a pathway for DIP production which is adaptable to Good Manufacturing Practice, so that their preclinical testing should be suitable for evaluation in subjects.

Dengue virus-free defective interfering particles have potent and broad anti-dengue virus activity.

Dengue virus (DENV) is spread from human to human through the bite of the female Aedes aegypti mosquito and leads to about 100 million clinical infections yearly. Treatment options and vaccine availability for DENV are limited. Defective interfering particles (DIPs) are considered a promising antiviral approach but infectious virus contamination has limited their development. Here, a DENV-derived DIP production cell line was developed that continuously produced DENV-free DIPs. The DIPs contained and could deliver to cells a DENV serotype 2 subgenomic defective-interfering RNA, which was originally discovered in DENV infected patients. The DIPs released into cell culture supernatant were purified and could potently inhibit replication of all DENV serotypes in cells. Antiviral therapeutics are limited for many viral infection. The DIP system described could be re-purposed to make antiviral DIPs for many other RNA viruses such as SARS-CoV-2, yellow fever, West Nile and Zika viruses.

GBP5 Repression Suppresses the Metastatic Potential and PD-L1 Expression in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype because of its high metastatic potential. Immune evasion due to aberrant expression of programmed cell death ligand 1 (PD-L1) has also been reported recently in metastatic TNBC. However, the mechanism underlying metastatic progression and PD-L1 upregulation in TNBC is still largely unknown. Here, we found that guanylate binding protein 5 (GBP5) is expressed in higher levels in TNBC tissues than in non-TNBC and normal mammary tissues and serves as a poorer prognostic marker in breast cancer patients. Transwell cultivation indicated that GBP5 expression is causally related to cellular migration ability in the detected TNBC cell lines. Moreover, the computational simulation of the gene set enrichment analysis (GSEA) program against the GBP5 signature generated from its coexpression with other somatic genes in TNBC revealed that GBP5 upregulation may be associated with the activation of interferon gamma (IFN-γ)-responsive and NF-κB-related signaling cascades. In addition, we found that the coexpression of GBP5 with PD-L1 was significantly positive correlation in TNBC tissues. Robustly, our data showed that GBP5 knockdown in TNBC cells harboring a higher GBP5 level dramatically suppresses the number of migrated cells, the activity of IFN-γ/STAT1 and TNF-α/NF-κB signaling axes, and the expression of PD-L1. Importantly, the signature combining a higher GBP5 and PD-L1 level predicted the shortest time interval of brain metastasis in breast cancer patients. These findings not only uncover the oncogenic function of GBP5 but also provide a new strategy to combat metastatic/immunosuppressive TNBC by targeting GBP5 activity.

Applications of Hyaluronic Acid in Ophthalmology and Contact Lenses.

Hyaluronic acid (HA) is a glycosaminoglycan that was first isolated and identified from the vitreous body of a bull's eye. HA is ubiquitous in the soft connective tissues of animals and therefore has high tissue compatibility for use in medication. Because of HA's biological safety and water retention properties, it has many ophthalmology-related applications, such as in intravitreal injection, dry eye treatment, and contact lenses. Due to its broad range of applications, the identification and quantification of HA is a critical topic. This review article discusses current methods for analyzing HA. Contact lenses have become a widely used medical device, with HA commonly used as an additive to their production material, surface coating, and multipurpose solution. HA molecules on contact lenses retain moisture and increase the wearer's comfort. HA absorbed by contact lenses can also gradually release to the anterior segment of the eyes to treat dry eye. This review discusses applications of HA in ophthalmology.

DNA polymerase theta repression enhances the docetaxel responsiveness in metastatic castration-resistant prostate cancer.

OBJECTIVE: Docetaxel remains a main treatment for metastatic castration-resistant prostate cancer (mCRPC); however, the development of docetaxel resistance has been found in some mCRPC patients. The aim of this work is to identify an effective biomarker for predicting therapeutic effectiveness of docetaxel in mCRPC patients. METHODS: We examined DNA polymerase theta (POLQ) expression in The Cancer Genome Atlas (TCGA) database and Tissue microarray. Kaplan-Meier analyses were performed to estimate the prognostic significance of POLQ. A series of functional analyses were conducted in cell lines and xenograft models. Regulated pathways were predicted by Geneset Enrichment Analysis (GSEA) software and further investigated by luciferase reporter and RT-PCR assays. RESULTS: We found that POLQ mRNA levels in CRPC tissues was significantly higher than that of other DNA polymerases in non-CRPC prostate tissues. POLQ upregulation was extensively detected in mCRPC and strongly predicted a poor prognosis. POLQ knockdown enhanced docetaxel sensitivity in a cell-based cytotoxicity assay and promoted the therapeutic effect on the tumor growth of metastatic PC-3M cells in xenograft models. The computational simulation by GSEA software significantly predicted the association between POLQ upregulation and the activation of E2F/G2M checkpoint-related pathways. Moreover, luciferase reporter and RT-PCR assays demonstrated that POLQ knockdown downregulated the transcriptional regulatory activity of E2F and repressed E2F/G2M checkpoint-regulated CDK1 in mCRPC cells. CONCLUSION: Our results suggest that POLQ serves as a predictive factor for poor docetaxel response and provide a novel strategy to enhance the anticancer effects of docetaxel therapy by targeting POLQ in mCRPC patients.

Expression of Rta in B Lymphocytes during Epstein-Barr Virus Latency.

Rta of Epstein-Barr virus (EBV) is thought to be expressed only during the lytic cycle to promote the transcription of lytic genes. However, we found that Rta is expressed in EBV-infected B cells during viral latency, at levels detectable by immunoblot analysis. Latent Rta expression cannot be attributed to spontaneous lytic activation, as we observed that more than 90% of Akata, P3HR1, and 721 cells latently infected by EBV express Rta. We further found that Rta is sequestered in the nucleolus during EBV latency through its interaction with MCRS2, a nucleolar protein. When Rta is sequestered in the nucleolus, it no longer activates RNA polymerase II-driven transcription, thus explaining why Rta expression during latency does not transactivate EBV lytic genes. Additional experiments showed that Rta can bind to 18S rRNA and become incorporated into ribosomes, and a transient transfection experiment showed that Rta promotes translation from an mRNA reporter. These findings reveal that Rta has novel functions beyond transcriptional activation during EBV latency and may have interesting implications for the concept of EBV latency.

Tat-Based Therapies as an Adjuvant for an HIV-1 Functional Cure.

The human immunodeficiency virus type 1 (HIV) establishes a chronic infection that can be well controlled, but not cured, by combined antiretroviral therapy (cART). Interventions have been explored to accomplish a functional cure, meaning that a patient remains infected but HIV is undetectable in the blood, with the aim of allowing patients to live without cART. Tat, the viral transactivator of transcription protein, plays a critical role in controlling HIV transcription, latency, and viral rebound following the interruption of cART treatment. Therefore, a logical approach for controlling HIV would be to block Tat. Tackling Tat with inhibitors has been a difficult task, but some recent discoveries hold promise. Two anti-HIV proteins, Nullbasic (a mutant of Tat) and HT1 (a fusion of HEXIM1 and Tat functional domains) inhibit viral transcription by interfering with the interaction of Tat and cellular factors. Two small molecules, didehydro-cortistatin A (dCA) and triptolide, inhibit Tat by different mechanisms: dCA through direct binding and triptolide through enhanced proteasomal degradation. Finally, two Tat-based vaccines under development elicit Tat-neutralizing antibodies. These vaccines have increased the levels of CD4+ cells and reduced viral loads in HIV-infected people, suggesting that the new vaccines are therapeutic. This review summarizes recent developments of anti-Tat agents and how they could contribute to a functional cure for HIV.

Strong In Vivo Inhibition of HIV-1 Replication by Nullbasic, a Tat Mutant.

Nullbasic is a mutant form of the HIV-1 transcriptional activator protein (Tat) that strongly inhibits HIV-1 transcription and replication in lymphocytes in vitro To investigate Nullbasic inhibition in vivo, we employed an NSG mouse model where animals were engrafted with primary human CD4+ cells expressing a Nullbasic-ZsGreen1 (NB-ZSG) fusion protein or ZSG. NB-ZSG and ZSG were delivered by using a retroviral vector where CD4+ cells were transduced either prior to (preinfection) or following (postinfection) HIV-1 infection. The transduced cells were analyzed in vitro up to 10 days postinfection (dpi) and in vivo up to 39 dpi. Compared to ZSG, NB-ZSG strongly inhibited HIV-1 replication both in vitro and in vivo using preinfection treatment. In vitro, HIV-1 mRNA levels in cells were reduced by up to 60-fold. In vivo, HIV-1 RNA was undetectable in plasma samples during the course of the experiment, and HIV-1 mRNA levels in resident CD4+ cells in organ tissue were reduced up to 2,800-fold. Postinfection treatment of HIV-1-infected cells with NB-ZSG attenuated HIV-1 infection for up to 14 days. In vitro, a 25-fold reduction of viral mRNA in cells was observed but diminished to a <2-fold reduction by 10 dpi. In vivo, HIV-1 RNA was undetectable in plasma of NB-ZSG mice at 14 dpi but afterwards was not significantly different between NB-ZSG mice and control mice. However, we observed higher levels of CD4+ cells in NB-ZSG mice than in control mice, suggesting that NB-ZSG imparted a survival advantage to HIV-1-infected animals.IMPORTANCE HIV-1 infection is effectively controlled by antiviral therapy that inhibits virus replication and reduces viral loads below detectable levels in patients. However, therapy interruption leads to viral rebound due to latently infected cells, which serve as a source of continued viral infection. Interest in strategies leading to a functional cure for HIV-1 infection by long-term or permanent viral suppression is growing. Here, we show that a mutant form of the HIV-1 Tat protein, referred to as Nullbasic, inhibits HIV-1 transcription in infected CD4+ cells in vivo Analysis shows that stable expression of Nullbasic in CD4+ cells could lead to durable anti-HIV-1 activity. Nullbasic, as a gene therapy candidate, could be a part of a functional-cure strategy to suppress HIV-1 transcription and replication.

eEF1A demonstrates paralog specific effects on HIV-1 reverse transcription efficiency.

The eukaryotic translation elongation factor 1A (eEF1A) has two cell-type specific paralogs, eEF1A1 and eEF1A2. Both paralogs undertake a canonical function in delivering aminoacyl-tRNA to the ribosome for translation, but differences in other functions are emerging. eEF1A1 has been reported to be important for the replication of many viruses, but no study has specifically linked the eEF1A2 paralog. We have previously demonstrated that eEF1A1 directly interacts with HIV-1 RT and supports efficient reverse transcription. Here, we showed that RT interacted more strongly with eEF1A1 than with eEF1A2 in immunoprecipitation assay. Biolayer interferometry using eEF1A paralogs showed different association and dissociation rates with RT. Over expressed eEF1A1, but not eEF1A2, was able to restore HIV-1 reverse transcription efficiency in HEK293T cells with endogenous eEF1A knocked-down and HIV-1 reverse transcription efficiency correlated with the level of eEF1A1 mRNA, but not to eEF1A2 mRNA in both HEK293T and primary human skeletal muscle cells.

Development of a rapid and economic in vivo electrocardiogram platform for cardiovascular drug assay and electrophysiology research in adult zebrafish.

Zebrafish is a popular and favorable model organism for cardiovascular research, with an increasing number of studies implementing functional assays in the adult stage. For example, the application of electrocardiography (ECG) in adult zebrafish has emerged as an important tool for cardiac pathophysiology, toxicity, and chemical screen studies. However, few laboratories are able to perform such functional analyses due to the high cost and limited availability of a convenient in vivo ECG recording system. In this study, an inexpensive ECG recording platform and operation protocol that has been optimized for adult zebrafish ECG research was developed. The core hardware includes integration of a ready-to-use portable ECG kit with a set of custom-made needle electrode probes. A combined anesthetic formula of MS-222 and isoflurane was first tested to determine the optimal assay conditions to minimize the interference to zebrafish cardiac physiology under sedation. For demonstration, we treated wild-type zebrafish with different pharmacological agents known to affect cardiac rhythms in humans. Conserved electrophysiological responses to these drugs were induced in adult zebrafish and recorded in real time. This economic ECG platform has the potential to facilitate teaching and training in cardiac electrophysiology with adult zebrafish and to promote future translational applications in cardiovascular medicine.

Extension of C. elegans lifespan using the ·NO-delivery dinitrosyl iron complexes.

The ubiquitous and emerging physiology function of endogenous nitric oxide in vascular, myocardial, immune, and neuronal systems prompts chemists to develop a prodrug for the controlled delivery of ·NO in vivo and for the translational biomedical application. Inspired by the discovery of natural [Fe(NO)2] motif, herein, we develop the synthetic dinitrosyl iron complexes (DNICs) [Fe2(µ-SR)2(NO)4] (1) as a universal platform for the O2-triggered release of ·NO, for the regulation of ·NO-release kinetics (half-life = 0.6-27.4 h), and for the activation of physiological function of ·NO. Using C. elegans as a model organism, the ·NO-delivery DNIC 1 regulates IIS signaling pathway, AMPK signaling pathway, and mitochondrial function pathway to extend the lifespan and to delay the aging process based on the lifespan analysis, SA-ßgal activity assay, and next-generation RNA sequencing analysis. This study unveils the anti-aging effect of ·NO and develops DNICs as a chemical biology probe for the continued discovery of unprecedented NO physiology.

Uncovering the regeneration strategies of zebrafish organs: a comprehensive systems biology study on heart, cerebellum, fin, and retina regeneration.

BACKGROUND: Regeneration is an important biological process for the restoration of organ mass, structure, and function after damage, and involves complex bio-physiological mechanisms including cell differentiation and immune responses. We constructed four regenerative protein-protein interaction (PPI) networks using dynamic models and AIC (Akaike's Information Criterion), based on time-course microarray data from the regeneration of four zebrafish organs: heart, cerebellum, fin, and retina. We extracted core and organ-specific proteins, and proposed a recalled-blastema-like formation model to uncover regeneration strategies in zebrafish. RESULTS: It was observed that the core proteins were involved in TGF-ß signaling for each step in the recalled-blastema-like formation model and TGF-ß signaling may be vital for regeneration. Integrins, FGF, and PDGF accelerate hemostasis during heart injury, while Bdnf shields retinal neurons from secondary damage and augments survival during the injury response. Wnt signaling mediates the growth and differentiation of cerebellum and fin neural stem cells, potentially providing a signal to trigger differentiation. CONCLUSION: Through our analysis of all four zebrafish regenerative PPI networks, we provide insights that uncover the underlying strategies of zebrafish organ regeneration.

Interaction between cytochrome P450 2A6 and Catechol-O-Methyltransferase genes and their association with smoking risk in young men.

BACKGROUND: Although some effects of gene-gene interactions on nicotine-dopamine metabolism for smoking behavior have been reported, polymorphisms of cytochrome P450 (CYP) 2A6 and catechol-O-methyltransferase (COMT) have not been studied together to determine their effects on smokers. The aim of this study was to investigate the effects of the interaction between the CYP 2A6 and COMT genes on smoking behavior in young Taiwanese men. RESULTS: A self-report questionnaire regarding smoking status was administered to 500 young men. Polymorphisms of the CYP 2A6 and COMT genes as well as urinary nicotine and urinary cotinine levels were determined. The odds ratio for starting smoking was significantly lower in subjects carrying a CYP2A6 low activity/variant COMT rs4680 genotype than in those possessing a CYP2A6 wild-type/variant COMT rs4680 genotype (0.44, 95% confidence interval = 0.19-0.98, P = 0.043). Comparisons of Fagerstrom Test for Nicotine Dependence (FTND), Physiological Cigarette Dependence Scale (PCDS), and Cigarette Withdrawal symptoms (CWS-21) among the smokers with different CYP2A6/COMT polymorphisms were not significantly different. The adjusted urinary nicotine concentrations were not significantly different between the two groups carrying different genotypes. The adjusted urinary cotinine level was significantly different between the COMT rs4680 wild-type group and COMT rs4680 variant group [92.46 ng/µL vs. 118.24 ng/µL (median value), P = 0.041] and between the COMT rs4680 wild-type/COMT rs165599 variant group and COMT rs4680 variant/COMT rs165599 variant group (97.10 ng/µL vs. 122.18 ng/µL, P = 0.022). CONCLUSIONS: These findings suggest that a single nucleotide polymorphism (rs4680) of the COMT gene and the interaction between the CYP 2A6 and COMT genes affect smoking status in young Taiwanese men.

A mutant Tat protein inhibits infection of human cells by strains from diverse HIV-1 subtypes.

BACKGROUND: Nullbasic is a mutant HIV-1 Tat protein that inhibits HIV-1 replication via three independent mechanisms that disrupts 1) reverse transcription of the viral RNA genome into a DNA copy, 2) HIV-1 Rev protein function required for viral mRNA transport from the nucleus to the cytoplasm and 3) HIV-1 mRNA transcription by RNA Polymerase II. The Nullbasic protein is derived from the subtype B strain HIV-1BH10 and has only been tested against other HIV-1 subtype B strains. However, subtype B strains only account for ~10% of HIV-1 infections globally and HIV-1 Tat sequences vary between subtypes especially for subtype C, which is responsible for ~50% HIV-1 infection worldwide. These differences could influence the ability of Tat to interact with RNA and cellular proteins and thus could affect the antiviral activity of Nullbasic. Therefore, Nullbasic was tested against representative HIV-1 strains from subtypes C, D and A/D recombinant to determine if it can inhibit their replication. METHODS: Nullbasic was delivered to human cells using a self-inactivating (SIN) γ-retroviral system. We evaluated Nullbasic-mCherry (NB-mCh) fusion protein activity against the HIV-1 strains in TZM-bl cell lines for inhibition of transactivation and virus replication. We also examined antiviral activity of Nullbasic-ZsGreen1 (NB-ZSG1) fusion protein against the same strains in primary CD4+ T cells. The Nullbasic expression was monitored by western blot and flow cytometry. The effects of Nullbasic on primary CD4+ T cells cytotoxicity, proliferation and apoptosis were also examined. RESULTS: The results show that Nullbasic inhibits Tat-mediated transactivation and virus replication of all the HIV-1 strains tested in TZM-bl cells. Importantly, Nullbasic inhibits replication of the HIV-1 strains in primary CD4+ T cells without affecting cell proliferation, cytotoxicity or level of apoptotic cells. CONCLUSION: A SIN-based γ-retroviral vector used to express Nullbasic fusion proteins improved protein expression particularly in primary CD4+ T cells. Nullbasic has antiviral activity against all strains from the subtypes tested although small differences in viral inhibition were observed. Further improvement of in γ-retroviral vector stable expression of Nullbasic expression may have utility in a future gene therapy approach applicable to genetically diverse HIV-1 strains.

Motor neuron-derived Thsd7a is essential for zebrafish vascular development via the Notch-dll4 signaling pathway.

BACKGROUND: Development of neural and vascular systems displays astonishing similarities among vertebrates. This parallelism is under a precise control of complex guidance signals and neurovascular interactions. Previously, our group identified a highly conserved neural protein called thrombospondin type I domain containing 7A (THSD7A). Soluble THSD7A promoted and guided endothelial cell migration, tube formation and sprouting. In addition, we showed that thsd7a could be detected in the nervous system and was required for intersegmental vessels (ISV) patterning during zebrafish development. However, the exact origin of THSD7A and its effect on neurovascular interaction remains unclear. RESULTS: In this study, we discovered that zebrafish thsd7a was expressed in the primary motor neurons. Knockdown of Thsd7a disrupted normal primary motor neuron formation and ISV sprouting in the Tg(kdr:EGFP/mnx1:TagRFP) double transgenic zebrafish. Interestingly, we found that Thsd7a morphants displayed distinct phenotypes that are very similar to the loss of Notch-delta like 4 (dll4) signaling. Transcript profiling further revealed that expression levels of notch1b and its downstream targets, vegfr2/3 and nrarpb, were down-regulated in the Thsd7a morphants. These data supported that zebrafish Thsd7a could regulate angiogenic sprouting via Notch-dll4 signaling during development. CONCLUSIONS: Our results suggested that motor neuron-derived Thsd7a plays a significant role in neurovascular interactions. Thsd7a could regulate ISV angiogenesis via Notch-dll4 signaling. Thus, Thsd7a is a potent angioneurin involved in the development of both neural and vascular systems.

Direct-growth carbon nanotubes on 3D structural microelectrodes for electrophysiological recording.

A novel 3D carbon nanotube (CNT) microelectrode was developed through direct growth of CNTs on a gold pin-shaped 3D microelectrode at a low temperature (400 °C) for applications in neural and cardiac recording. With an electroplated Ni catalyst layer covering the entire surface of the pin-shaped structure, CNTs were synthesized on a 3D microelectrode by catalytic thermal chemical vapor deposition (CVD). According to the analyses by electrochemical impedance spectroscopy, the impedance of 3D microelectrodes after CNT growth and UV/O3 treatment decreased from 9.3 Ω mm(-2) to 1.2 Ω mm(-2) and the capacitance increased largely from 2.2 mF cm(-2) to 73.3 mF cm(-2). The existence of UVO3-treated CNT led to a large improvement of interfacial capacitance, contributing to the decrease of impedance. The electrophysiological detection capability of this 3D CNT microelectrode was demonstrated by the distinguished P waves, QRS complex and T waves in the electrocardiogram of the zebrafish heart and the action potential recorded from individual rat hippocampal neurons. The compatibility of integration with ICs, high resolution in space, electrophysiological signals, and non-invasive long-term recording suggest that the 3D CNT microelectrode exhibits promising potential for applications in electrophysiological research and clinical trials.

Specific Interaction between eEF1A and HIV RT Is Critical for HIV-1 Reverse Transcription and a Potential Anti-HIV Target.

Reverse transcription is the central defining feature of HIV-1 replication. We previously reported that the cellular eukaryotic elongation factor 1 (eEF1) complex associates with the HIV-1 reverse transcription complex (RTC) and the association is important for late steps of reverse transcription. Here we show that association between the eEF1 and RTC complexes occurs by a strong and direct interaction between the subunit eEF1A and reverse transcriptase (RT). Using biolayer interferometry and co-immunoprecipitation (co-IP) assays, we show that association between the eEF1 and RTC complexes occurs by a strong (KD ~3-4 nM) and direct interaction between eEF1A and reverse transcriptase (RT). Biolayer interferometry analysis of cell lysates with titrated levels of eEF1A indicates it is a predominant cellular RT binding protein. Both the RT thumb and connection domains are required for interaction with eEF1A. A single amino acid mutation, W252A, within the thumb domain impaired co-IP between eEF1A and RT, and also significantly reduced the efficiency of late reverse transcription and virus replication when incorporated into infectious HIV-1. Molecular modeling analysis indicated that interaction between W252 and L303 are important for RT structure, and their mutation to alanine did not impair heterodimerisation, but negatively impacted interaction with eEF1A. Didemnin B, which specifically binds eEF1A, potently inhibited HIV-1 reverse transcription by greater than 2 logs at subnanomolar concentrations, especially affecting reverse transcription late DNA synthesis. Analysis showed reduced levels of RTCs from HIV-1-infected HEK293T treated with didemnin B compared to untreated cells. Interestingly, HIV-1 with a W252A RT mutation was resistant to didemnin B negative effects showing that didemnin B affects HIV-1 by targeting the RT-eEF1A interaction. The combined evidence indicates a direct interaction between eEF1A and RT is crucial for HIV reverse transcription and replication, and the RT-eEF1A interaction is a potential drug target.

Binding of the eukaryotic translation elongation factor 1A with the 5'UTR of HIV-1 genomic RNA is important for reverse transcription.

BACKGROUND: The cellular protein eukaryotic translation elongation factor 1A (eEF1A) binds to aminoacylated transfer RNAs and delivers them to the ribosome during translation. eEF1A also binds to RNA secondary structures present in genomes of several RNA viruses and plays important roles in their replication. As a RNA binding protein, whether eEF1A can bind with HIV-1 genomic RNA has not been investigated and was the aim of the study. METHODS: RNA-protein interaction was determined by reversible crosslink co-immunoprecipitation (RC-Co-IP) and biolayer Interferometry assay (BLI). eEF1A binding region within RNA was mapped by deletion and mutation analysis. Virus with genomic RNA mutations were examined for eEF1A-RT interaction by proximity ligation assay, for reverse transcription by qPCR and for replication by CAp24 ELISA in cells. RESULTS: The interaction of eEF1A with 5'UTR of HIV-1 genomic RNA was detected in cells and in vitro. Truncation and substitution mutations in the 5'UTR RNA demonstrated that a stem-loop formed by nucleotides 142 to 170, which encompass a reported tRNA anticodon-like-element, binds to eEF1A. Mutations that altered the stem-loop structure by changing two highly conserved sequence clusters in the stem-loop region result in reduction of the interaction with eEF1A in vitro. HIV-1 virus harbouring the same 5'UTR mutations significantly reduced the interaction of eEF1A with HIV-1 reverse transcription complex (RTC), reverse transcription and replication. CONCLUSION: eEF1A interacts with 5'UTR of HIV-1 genomic RNA and the interaction is important for late DNA synthesis in reverse transcription.

Effects of Interaction Between Dopamine D2 Receptor and Monoamine Oxidase A Genes on Smoking Status in Young Men.

Although the effect of gene-gene interaction on nicotine-dopamine metabolism for smoking behavior has been reported, polymorphisms of dopamine D2 receptor (DRD2) and monoamine oxidase A (MAOA) have not been simultaneously examined among smokers. In this study, 481 young Taiwanese men completed a self-report questionnaire on smoking status, and data were obtained on polymorphisms of DRD2 rs1800497, DRD2 rs1079597, MAOA rs309850, and MAOA rs1137070, urinary nicotine, and urinary cotinine. In a comparison of 261 current smokers and 220 never smokers, odds ratios (ORs) for the development of smoking in all genotypes were not statistically significant. Among smokers with DRD2 rs1079597 GG//MAOA rs309850 3-repeat, the OR of heavier smoking was 2.67 times higher (95% confidence interval [CI]: [1.08, 6.59], p = .031) and the score on the Fagerstrom test for nicotine dependence was higher (4.26 vs. 2.83) than in those with DRD2 rs1079597 AA//MAOA rs309850 3-repeat. Adjusted urinary cotinine concentration was significantly different between those two groups (median value: 95.83 ng/µl vs. 133.24 ng/µl, respectively, p = .045). These findings suggest that the interaction of DRD2 rs1079597 and MAOA rs309850 3-repeat affects smoking intensity in young Taiwanese men.