Identification of a Non-Nucleoside Reverse Transcriptase Inhibitor against Human Immunodeficiency Virus-1.

The HIV-1 infection epidemic remains a global health problem. Current antiretroviral treatments are effective in controlling the progression of a severe infection. However, the emergence of drug resistance requires an urgent identification of new treatment regimes. HIV-1 reverse transcriptase (RTs) has been a successful therapeutic target owing to its high specificity and potent antiviral properties; therefore, it has become an essential component of current HIV-1 standard treatments. This study identified a new HIV-1 RTs inhibitor (Compound #8) that is structurally unique and greatly effective against HIV-1 through chemical library screening and a medicinal chemistry program by analyzing the structure-activity relationship (SAR). Further analysis of molecular docking and mechanisms of action demonstrated that Compound #8 is a novel type of HIV-1 non-nucleoside reverse transcriptase inhibitor (NNRTI) with a flexible binding mode. Therefore, it exhibits great therapeutic potential when combined with other existing HIV-1 drugs. Our current studies suggest that Compound #8 is a promising novel scaffold for the development of new HIV-1 treatments.

A Novel Time-Resolved Fluorescence Resonance Energy Transfer Assay for the Discovery of Small-Molecule Inhibitors of HIV-1 Tat-Regulated Transcription.

Human immunodeficiency virus-1 (HIV-1) transactivator (Tat)-mediated transcription is essential for HIV-1 replication. It is determined by the interaction between Tat and transactivation response (TAR) RNA, a highly conserved process representing a prominent therapeutic target against HIV-1 replication. However, owing to the limitations of current high-throughput screening (HTS) assays, no drug that disrupts the Tat-TAR RNA interaction has been uncovered yet. We designed a homogenous (mix-and-read) time-resolved fluorescence resonance energy transfer (TR-FRET) assay using europium cryptate as a fluorescence donor. It was optimized by evaluating different probing systems for Tat-derived peptides or TAR RNA. The specificity of the optimal assay was validated by mutants of the Tat-derived peptides and TAR RNA fragment, individually and by competitive inhibition with known TAR RNA-binding peptides. The assay generated a constant Tat-TAR RNA interaction signal, discriminating the compounds that disrupted the interaction. Combined with a functional assay, the TR-FRET assay identified two small molecules (460-G06 and 463-H08) capable of inhibiting Tat activity and HIV-1 infection from a large-scale compound library. The simplicity, ease of operation, and rapidity of our assay render it suitable for HTS to identify Tat-TAR RNA interaction inhibitors. The identified compounds may also act as potent molecular scaffolds for developing a new HIV-1 drug class.

Analysis of intake trends of kimchi, fruits and vegetables (1998–2020) and factors associated with the intake (2016–2020): based on the Korea National Health and Nutrition Examination Survey / 한국영양학회지

Purpose@#This study aimed to analyze the trends in kimchi, vegetable, and fruit consumption among the Korean population and identify the factors associated with this consumption.The goal was to provide fundamental data for developing appropriate guidelines to increase kimchi consumption by understanding its characteristics. @*Methods@#The analysis utilized data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 1998 and 2020. A total of 81,680 adults, aged 30 years or older, were included in the trend analysis. For the analysis of factors associated with kimchi, vegetable, and fruit intake, a subgroup of 22,122 adults aged 30 years or older from the KNHANES (2016-2020) was divided into two groups: 30–64 years old and 65 years old or older. Since the KNHANES data employed a complex sampling design, the statistical analysis was conducted using the appropriate complex sampling design method. @*Results@#The overall consumption of kimchi exhibited a declining trend among both men and women. Specifically, there was a significant decline in the intake of baechu kimchi among both genders. The decline in kimchi consumption above the standard was associated with a decrease in meal frequency and an increase in the frequency of eating alone. However, the patterns for unsalted vegetables and fruits differed compared to kimchi. @*Conclusion@#In this study, there was a decline in kimchi consumption among both men and women, and the potential factors associated with this trend included Westernized dietary habits, the presence of a spouse who influenced dietary habits, and an increased frequency of solitary dining due to the rise in single-person households. Therefore, it is necessary to develop dietary guidelines that consider these factors.

Investigation of the effect of SRSF9 overexpression on HIV-1 production.

Serine-arginine-rich splicing factors (SRSFs) are members of RNA processing proteins in the serine-arginine-rich (SR) family that could regulate the alternative splicing of the human immunodeficiency virus-1 (HIV-1). Whether SRSF9 has any effect on HIV-1 regulation requires elucidation. Here, we report for the first time the effects and mechanisms of SRSF9 on HIV-1 regulation. The overexpression of SRSF9 inhibits viral production and infectivity in both HEK293T and MT-4 cells. Deletion analysis of SRSF9 determined that the RNA regulation motif domain of SRSF9 is important for anti-HIV-1 effects. Furthermore, overexpression of SRSF9 increases multiple spliced forms of viral mRNA, such as Vpr mRNA. These data suggest that SRSF9 overexpression inhibits HIV-1 production by inducing the imbalanced HIV-1 mRNA splicing that could be exploited further for a novel HIV-1 therapeutic molecule. [BMB Reports 2022; 55(12): 639-644].

Identification of Novel Nucleocapsid Chimeric Proteins Inhibiting HIV-1 Replication.

The positive transcription elongation factor b (P-TEFb) is an essential factor that induces transcription elongation and is also negatively regulated by the cellular factor HEXIM1. Previously, the chimeric protein HEXIM1-Tat (HT) was demonstrated to inhibit human immunodeficiency virus-1 (HIV)-1 transcription. In this study, we attempted to develop an improved antiviral protein that specifically binds viral RNA (vRNA) by fusing HT to HIV-1 nucleocapsid (NC). Thus, we synthesized NC-HEXIM1-Tat (NHT) and HEXIM1-Tat-NC (HTN). NHT and HTN inhibited virus proliferation more effectively than HT, and they did not attenuate the function of HT. Notably, NHT and HTN inhibited the infectivity of the progeny virus, whereas HT had no such effect. NHT and HTN selectively and effectively interacted with vRNA and inhibited the proper packaging of the HIV-1 genome. Taken together, our results illustrated that the novel NC-fused chimeric proteins NHT and HTN display novel mechanisms of anti-HIV effects by inhibiting both HIV-1 transcription and packaging.

Investigation of the effect of Staufen1 overexpression on the HIV-1 virus production.

In this study, we investigated how Staufen1 influences the HIV-1 production. The overexpression of Staufen1 increased virus production without any negative affect on the viral infectivity. This increase was not caused by transcriptional activation; but by influencing post-transcriptional steps. Using multiple Gag protein derivatives, we confirmed that the zinc-finger domains of the HIV-1 nucleocapsid (NC) are important for its interaction with Staufen1. We also found that Staufen1 colocalized in stress granules with the mature form of the HIV-1 NC protein. [BMB Reports 2021; 54(11): 551-556].

Understanding of the functional role(s) of the Activating Transcription Factor 4(ATF4) in HIV regulation and production.

The activating transcription factor (ATF) 4 belongs to the ATF/CREB (cAMP Response Element Binding bZIP [Basic Leucine Zipper]) transcription factor family, and plays a central role in the UPR (Unfolded Protein Response) process in cells. The induction of ATF4 expression has previously been shown to increase the replication of HIV-1. However, the detailed mechanism underlying this effect and the factors involved in the regulation of ATF4 function are still unknown. Here, we demonstrate first that knocking out ATF4 using siRNA shows a strong negative effect on HIV-1 production, indicating that ATF4 is a functional positive cellular factor in HIV-1 production. To determine the mechanism by which ATF4 regulates the HIV-1 life cycle, we assessed the effect of the overexpression of wild type ATF4 and its various derivatives on HIV-1 LTR-mediated transcriptional activation and the production of HIV-1 particles. This effect was studied through co-transfection experiments with either reporter vectors or proviral DNA. We found that the N-terminal domains of ATF4 are involved in HIV-1 LTR-mediated transcriptional activation, and thus in HIV-1 production. [BMB Reports 2018; 51(8): 388-393].

Investigation of functional roles of transcription termination factor-1 (TTF-I) in HIV-1 replication.

Transcription termination factor-1 (TTF-I) is an RNA polymerase 1-mediated transcription terminator and consisting of a C-terminal DNA-binding domain, central domain, and N-terminal regulatory domain. This protein binds to a so-called 'Sal box' composed of an 11-base pair motif. The interaction of TTF-I with the 'Sal box' is important for many cellular events, including efficient termination of RNA polymerase-1 activity involved in pre-rRNA synthesis and formation of a chromatin loop. To further understand the role of TTF-I in human immunodeficiency virus (HIV)-I virus production, we generated various TTF-I mutant forms. Through a series of studies of the over-expression of TTF-I and its derivatives along with co-transfection with either proviral DNA or HIV-I long terminal repeat (LTR)-driven reporter vectors, we determined that wild-type TTF-I downregulates HIV-I LTR activity and virus production, while the TTF-I Myb-like domain alone upregulated virus production, suggesting that wild-type TTF-I inhibits virus production and trans-activation of the LTR sequence; the Myb-like domain of TTF-I increased virus production and trans-activated LTR activity. [BMB Reports 2018; 51(7): 338-343].

Investigation of function and regulation of the YB-1 cellular factor in HIV replication.

Y-box binding protein 1 (YB-1) is a member of the cold-shock domain (CSD) protein superfamily. It participates in a wide variety of cellular events, including transcription, RNA splicing, translation, DNA repair, drug resistance, and stress responses. We investigated putative functions of YB-1 in HIV-1 replication. Functional studies using overexpression or knockdown of YB-1 in conjunction with transfection of proviral DNA showed that YB-1 enhances virus production. We found YB-1 regulates HIV-1 production by stimulating viral transcription using HIV-1 LTR sequence U3RU5 with Luciferase assay. We also identified a specific region from amino acids 1 to 324 of YB-1 as necessary for the participation of the protein in the production of virions. [BMB Reports 2018; 51(6): 290-295].

HIV-1 nucleocapsid protein localizes efficiently to the nucleus and nucleolus.

The HIV-1 nucleocapsid (NC) is an essential viral protein containing two highly conserved retroviral-type zinc finger (ZF) motifs, which functions in multiple stages of the HIV-1 life cycle. Although a number of functions for NC either in its mature form or as a domain of Gag have been revealed, little is known about the intracellular localization of NC and, moreover, its role in Gag protein trafficking. Here, we have investigated various forms of HIV-1 NC protein for its cellular localization and found that the NC has a strong nuclear and nucleolar localization activity. The linker region, composed of a stretch of basic amino acids between the two ZF motifs, was necessary and sufficient for the activity.

Identification and characterization of a new type of inhibitor against the human immunodeficiency virus type-1 nucleocapsid protein.

BACKGROUND: The human immunodeficiency virus type-1 (HIV-1) nucleocapsid protein (NC) is an essential and multifunctional protein involved in multiple stages of the viral life cycle such as reverse transcription, integration of proviral DNA, and especially genome RNA packaging. For this reason, it has been considered as an attractive target for the development of new anti-HIV drugs. Although a number of inhibitors of NC have been reported thus far, the search for NC-specific and functional inhibitor(s) with a good antiviral activity continues. RESULTS: In this study, we report the identification of A1752, a small molecule with inhibitory action against HIV-1 NC, which shows a strong antiviral efficacy and an IC50 around 1 µM. A1752 binds directly to HIV-1 NC, thereby inhibiting specific chaperone functions of NC including Psi RNA dimerization and complementary trans-activation response element (cTAR) DNA destabilization, and it also disrupts the proper Gag processing. Further analysis of the mechanisms of action of A1752 also showed that it generates noninfectious viral particles with defects in uncoating and reverse transcription in the infected cells. CONCLUSIONS: These results demonstrate that A1752 is a specific and functional inhibitor of NC with a novel mode of action and good antiviral efficacy. Thus, this agent provides a new type of anti-HIV NC inhibitor candidate for further drug development.

Development of a functional cell-based assay that probes the specific interaction between influenza A virus NP and its packaging signal sequence RNA.

Although cis-acting packaging signal RNA sequences for the influenza virus NP encoding vRNA have been identified recently though genetic studies, little is known about the interaction between NP and the vRNA packaging signals either in vivo or in vitro. Here, we provide evidence that NP is able to interact specifically with the vRNA packaging sequence RNA within living cells and that the specific RNA binding activity of NP in vivo requires both the N-terminal and central region of the protein. This assay established would be a valuable tool for further detailed studies of the NP-packaging signal RNA interaction in living cells.

Identification of a novel type of small molecule inhibitor against HIV-1.

Here we report a new chemical inhibitor against HIV-1 with a novel structure and mode of action. The inhibitor, designated as A1836, inhibited HIV-1 replication and virus production with a 50% inhibitory concentration (IC50) of 2.0 µM in an MT-4 cell-based and cytopathic protection antiviral assay, while its 50% cytotoxic concentration (CC50) was much higher than 50 µM. Examination of the effect of A1836 on in vitro HIV-1 reverse transcriptase (RT) and integrase showed that neither were molecular targets of A1836. The characterization and re-infection assay of the HIV-1 virions generated in the presence of A1836 showed that the synthesis of early RT products in the cells infected with the virions was inhibited dose-dependently, due in part to abnormal protein formation within the virions, thus resulting in an impaired infectivity. These results suggest that A1836 might be a novel candidate for the development of a new type of HIV-1 inhibitor.

The HIV-1 nucleocapsid protein does not function as a transcriptional activator on its own cognate promoter.

The human immunodeficiency virus type 1 (HIV-1) nucleocapsid (NC) is a multifunctional, zinc finger-containing protein known to be involved in almost every step of the viral life cycle. We therefore examined the effects of NC in vivo as a transcription activator on the basal transcriptional activity of the HIV-1 U3 and Rous sarcoma virus (RSV) promoters, as well as HIV-1 long terminal repeats (LTRs) such as the U3R and U3RU5 regions, using promoter-fused reporter gene assays, Western blot analyses, and quantitative real time-polymerase chain reaction. From these studies, we found that the basal transcriptional levels of the HIV-1 U3 and RSV promoters were barely enhanced by the presence of NC. Placing the U3R region upstream of reporter genes greatly increased transcriptional activity compared to that of the U3 promoter alone, and such activity was further increased by Tat expression. However, neither transcription driven by U3R itself nor Tat-mediated transcriptional activation of the U3R was further increased by the addition of NC. Similar results were also observed with U3RU5 of the HIV-1 LTR region in the presence of either NC or Gag protein. Thus, these results indicate that the HIV NC protein is unable to act as a transcriptional activator on its cognate and possibly other retroviral promoters.

Identification of in vivo interaction between Hepatitis C Virus core protein and 5' and 3' UTR RNA.

Here, we investigated the ability of the Hepatitis C Virus (HCV) core protein to interact specifically with the 5' and 3' untranslated regions (UTRs) of HCV using an in vivo cell-based translation inhibition assay. HCV core protein interacts weakly but specifically with the SLIII stem loop in the 5' UTR in which the SLIIIb subdomain is the major determinant and the SL2 loop in the X region of the 3' UTR. These results revealed for the first time in vivo interaction of the core protein with 5' and 3' UTRs involved in the viral life cycle. This system provides a useful tool for further investigating interactions between the HCV core protein and 5' and 3' UTRs.

Radiopharmaceuticals Used in Cardiac Imaging / 핵의학분자영상

Many radiopharmaceuticals have been developed and wildy used in the imaging cardiac function. Myocardial perfusion imaging (MPI) is a well established noninvasive method of assessing coronary blood flow and has been widely used in patients diagnosed or suspected with coronary artery diseases. The innovation of radiopharmaceuticals used in the cardiac imaging is one of the most important contributors to the development of nuclear cardiology. Thallium-201 and various technetium-99m agents have been globally used for myocardial perfusion SPECT, and N-13 ammonia (13NH3), rubidium-82 (82Rb), O-15 water (H215O) for myocardial perfusion PET. As well as the cardiac perfusion studies, new radiopharmaceuticals that visualize fat metabolism or receptors of the sympathetic nervous system have successfully been applied to clinical practice. Useful information can be obtained for diagnosing coronary artery disease, evaluating patients' condition, or assessing therapeutic effects. In this review, we describe the characteristics and clinical usefulness of radiopharmaceuticals used for cardiac SPECT and PET.

Two Cases of Pregnancies Complicated with Central Diabetes Insipidus / 대한산부인과학회지

Diabetes insipidus is an unusual cause of urinary frequency during pregnancy. It occurs in 2 to 6 per 100,000 pregnancies. It is a disorder in which the abnormal secretion, degradation, or activity of vasopressin cause hypotonic polyuria, polydipsia, and dehydration. And this syndrome appears to be associated with multiple gestations, preeclampsia, and abnormal liver function. We report two cases of pregnancies complicated with diabetes insipidus. One patient was diagnosed during pregnancy and DDAVP (L-deamino-8-d-arginine vasopressin) was used to manage diabetes insipidus. The other patient was diagnosed before pregnancy and DDAVP was not used.

The Influence of Embryo Transfer Catheter on the Outcome of In Vitro Fertilization and Embryo Transfer / 대한산부인과학회잡지

OBJECTIVE: To compare the efficacy of two different embryo transfer catheters, Norfolk and Wallace, in terms of the outcome of in vitro fertilization and embryo trabsfer (IVF-ET). METHODS: One hundred and seventy-one IVF-ET cycles performed in 132 infertile couples were included in this retrospective study. The couples were subjected to two different embryo transfer catheter types: Norfolk catheter group (92 cycles) and Wallace catheter group (79 cycles). Controlled ovarian hyperstimulation (COH) was performed using step-down protocol with GnRH agonist or antagonist. Four or less embryos were transferred on day 2 or 3 after oocyte retrieval. The luteal phase was supported by intramuscular progesterone (Progest) or intravaginal 8% progesterone gel (Crinone). RESULTS: The pregnancy rate per ET and the implantation rate were significantly higher in Wallace catheter group, respectively (20.7% vs. 34.2%, p=0.047; 9.7% vs. 15.1%, p=0.047). No statistically significant differences were observed in the other parameters between the two groups. CONCLUSION: The Wallace catheter showed better IVF-ET outcomes when compared with the Norfolk catheter in our study. Further prospective randomized controlled studies in a larger scale will be necessary to confirm our findings.

Annual Report on External Quality Assessment in Diagnostic Genetics in Korea (2003) / 임상검사와정도관리

The importance of quality control for dramatically growing genetic tests continues to be emphasized with increasing clinical demands. Diagnostic genetics subcommitee of KSQACP performed two trials for cytogenetic study in 2003. Cytogenetic surveys were performed by 33 laboratories and answered correctly in most laboratories except some problems in nomenclature and analysis for FISH and complex cytogenetic abnormalities in neoplasia. The molecular genetic test surveys include M. tuberculosis, HBV, HPV, leukemia/lymphoma, ApoE genotyping, Duchenne muscular dystrophy, myoclonic epilepsy and ragged red muscle fibers, and spinal and bulbar muscular atrophy. HPV, myoclonic epilepsy and ragged red muscle fibers, and spinal and bulbar muscular atrophy were the first challenge of the genetic survey. Molecular genetic survey showed excellent results in most participants, however, HPV tests should be improved by quality control in a few laboratories. External quality assessment program for cytogenetic analysis could be helpful to give participants many chances of continuous education and of interesting case materials.

Annual Report on External Quality Assessment in Diagnostic Genetics in Korea (2002) / 임상검사와정도관리

The importance of quality control for dramatically growing genetic tests continues to be emphasized with increasing clinical demands. Diagnostic genetics subcommitee of KSQACP performed two trials for cytogenetic study in 2002. Cytogenetic surveys were performed by 33 laboratories and answered correctly in most laboratories except some problems in nomenclature and analysis for mosaicism and cytogenetics of neoplasia. The molecular genetic test surveys include M. tuberculosis, HCV, HBV, leukemia/lymphoma, ABO genotyping, ApoE genotyping, spinocerebellar ataxia (SCA), spinal muscular atrophy (SMA), and mitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes (MELAS). HBV, SCA, SMA, MELAS tests were the first challenge of the genetic survey. Molecular genetic survey showed excellent results in most participants, however, ABO genotyping tests should be improved by new methods in a few laboratories. External quality assessment program for diagnostic genetics could be helpful to give participants many chances of continuous education and of interesting case materials.