scholarly journals Host poly(A) polymerases PAPD5 and PAPD7 provide two layers of protection that ensure the integrity and stability of hepatitis B virus RNA

2021 ◽  
Author(s):  
Fei Liu ◽  
Amy C. H. Lee ◽  
Fang Guo ◽  
Andrew S. Kondratowicz ◽  
Holly M. Micolochick Steuer ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Small Molecule ◽  
Dominant Role ◽  
Regulatory Element ◽  
Rna Metabolism ◽  
Host Factors ◽  
Health Concern ◽  
Genetic Studies

Noncanonical poly(A) polymerases PAPD5 and PAPD7 (PAPD5/7) stabilize HBV RNA via the interaction with the viral post-transcriptional regulatory element (PRE), representing new antiviral targets to control HBV RNA metabolism, HBsAg production and viral replication. Inhibitors targeting these proteins are being developed as antiviral therapies, therefore it is important to understand how PAPD5/7 coordinate to stabilize HBV RNA. Here, we utilized a potent small-molecule AB-452 as a chemical probe, along with genetic analyses to dissect the individual roles of PAPD5/7 in HBV RNA stability. AB-452 inhibits PAPD5/7 enzymatic activities and reduces HBsAg both in vitro (EC 50 ranged from 1.4 to 6.8 nM) and in vivo by 0.93 log 10 . Our genetic studies demonstrate that the stem-loop alpha sequence within PRE is essential for both maintaining HBV poly(A) tail integrity and determining sensitivity towards the inhibitory effect of AB-452. Although neither single knock-out (KO) of PAPD5 nor PAPD7 reduces HBsAg RNA and protein production, PAPD5 KO does impair poly(A) tail integrity and confers partial resistance to AB-452. In contrast, PAPD7 KO did not result in any measurable changes within the HBV poly(A) tails, but cells with both PAPD5 and PAPD7 KO show reduced HBsAg production and conferred complete resistance to AB-452 treatment. Our results indicate that PAPD5 plays a dominant role in stabilizing viral RNA by protecting the integrity of its poly(A) tail, while PAPD7 serves as a second line of protection. These findings inform PAPD5 targeted therapeutic strategies and open avenues for further investigating PAPD5/7 in HBV replication. Importance Chronic hepatitis B affects more than 250 million patients and is a major public health concern worldwide. HBsAg plays a central role in maintaining HBV persistence and as such, therapies that aim at reducing HBsAg through destabilizing or degrading HBV RNA have been extensively investigated. Besides directly degrading HBV transcripts through antisense oligonucleotides or RNA silencing technologies, small-molecule compounds targeting host factors such as the noncanonical poly(A) polymerase PAPD5 and PAPD7 have been reported to interfere with HBV RNA metabolism. Herein, our antiviral and genetic studies using relevant HBV infection and replication models further characterize the interplays between the cis-element within the viral sequence and the trans-elements from the host factors. PAPD5/7 targeting inhibitors, with oral bioavailability, thus represent an opportunity to reduce HBsAg through destabilizing HBV RNA.

scholarly journals Host poly(A) polymerases PAPD5 and PAPD7 provide two layers of protection that ensure the integrity and stability of hepatitis B virus RNA

2021 ◽  
Author(s):  
Fei Liu ◽  
Amy C.H Lee ◽  
Fang Guo ◽  
Andrew S. Kondratowicz ◽  
Holly M Micolochick Steuer ◽  
...  
Keyword(s):  
Dominant Role ◽  
Regulatory Element ◽  
Rna Stability ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Stem Loop ◽  
Knock Out ◽  
The Individual

Noncanonical poly(A) polymerases PAPD5 and PAPD7 (PAPD5/7) stabilize HBV RNA via the interaction with the viral post-transcriptional regulatory element (PRE), representing new antiviral targets to control HBV RNA metabolism, HBsAg production and viral replication. Inhibitors targeting these proteins are being developed as antiviral therapies, therefore it is important to understand how PAPD5/7 coordinate to stabilize HBV RNA. Here, we utilized a potent small-molecule AB-452 as a chemical probe, along with genetic analyses to dissect the individual roles of PAPD5/7 in HBV RNA stability. AB-452 inhibits PAPD5/7 enzymatic activities and reduces HBsAg both in vitro (EC50 ranged from 1.4 to 6.8 nM) and in vivo by 0.93 log10. Our genetic studies demonstrate that the stem-loop alpha sequence within PRE is essential for both maintaining HBV poly(A) tail integrity and determining sensitivity towards the inhibitory effect of AB-452. Although neither single knock-out (KO) of PAPD5 nor PAPD7 reduces HBsAg RNA and protein production, PAPD5 KO does impair poly(A) tail integrity and confers partial resistance to AB-452. In contrast, PAPD7 KO could not result in any measurable phenotypic changes, but displays a similar antiviral effect as AB-452 treatment when PAPD5 is depleted simultaneously. PAPD5/7 double KO confers complete resistance to AB-452 treatment. Our results thus indicate that PAPD5 plays a dominant role in stabilizing viral RNA by protecting the integrity of its poly(A) tail, while PAPD7 serves as a second line of protection. These findings inform PAPD5 targeted therapeutic strategies and open avenues for further investigating PAPD5/7 in HBV replication.

scholarly journals Engineered Small-Molecule Control of Influenza A Virus Replication

2018 ◽  
Vol 93 (1) ◽  
Author(s):  
Elizabeth J. Fay ◽  
Stephanie L. Aron ◽  
Ian A. Stone ◽  
Barbara M. Waring ◽  
Richard K. Plemper ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Small Molecule ◽  
Human Population ◽  
Influenza A ◽  
Health Concern ◽  
Highly Pathogenic ◽  
Significant Safety

ABSTRACT Influenza A virus (IAV) remains a global health concern despite the availability of a seasonal vaccine. It is difficult to predict which strains will circulate during influenza season, and therefore, it is extremely challenging to test novel vaccines in the human population. To overcome this obstacle, new vaccines must be tested in challenge studies. This approach poses significant safety problems, since current pharmacological interventions for IAV are poorly efficacious. New methods are needed to enhance the safety of these challenge studies. In this study, we have generated a virus expressing a small-molecule-assisted shutoff (SMASh) tag as a safety switch for IAV replication. The addition of the SMASh tag to an essential IAV protein allows for small-molecule-mediated inhibition of replication. Treatment with this drug controls the replication of a SMASh-tagged virus in vitro and in vivo. This model for restriction of viral replication has potential for broad applications in vaccine studies, virotherapy, and basic virus research. IMPORTANCE Influenza A virus (IAV) causes significant morbidity and mortality annually worldwide, despite the availability of new formulations of the vaccine each season. There is a critical need to develop more-efficacious vaccines. However, testing novel vaccines in the human population in controlled studies is difficult due to the limited availability and efficacy of intervention strategies should the vaccine fail. There are also significant safety concerns for work with highly pathogenic IAV strains in the laboratory. Therefore, novel strategies are needed to improve the safety of vaccine studies and of research on highly pathogenic IAV. In this study, we developed an IAV strain engineered to contain a small-molecule-mediated safety switch. This tag, when attached to an essential viral protein, allows for the regulation of IAV replication in vitro and in vivo. This strategy provides a platform for the regulation of virus replication without targeting viral proteins directly.

Chickpea (Cicer arietinum L.) Lectin Exhibit Inhibition of ACE-I, α-amylase and α-glucosidase Activity

2019 ◽  
Vol 26 (7) ◽  
pp. 494-501 ◽  
Author(s):  
Sameer Suresh Bhagyawant ◽  
Dakshita Tanaji Narvekar ◽  
Neha Gupta ◽  
Amita Bhadkaria ◽  
Ajay Kumar Gautam ◽  
...  
Keyword(s):  
Biological Effects ◽  
Exchange Chromatography ◽  
Health Concern ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ic50 Values ◽  
Chickpea Lectin

Background: Diabetes and hypertension are the major health concern and alleged to be of epidemic proportions. This has made it a numero uno subject at various levels of investigation. Glucosidase inhibitor provides the reasonable option in treatment of Diabetes Mellitus (DM) as it specifically targets post prandial hyperglycemia. The Angiotensin Converting Enzyme (ACE) plays an important role in hypertension. Therefore, inhibition of ACE in treatment of elevated blood pressure attracts special interest of the scientific community. Chickpea is a food legume and seeds contain carbohydrate binding protein- a lectin. Some of the biological properties of this lectin hitherto been elucidated. Methods: Purified by ion exchange chromatography, chickpea lectin was tested for its in vitro antioxidant, ACE-I inhibitory and anti-diabetic characteristic. Results: Lectin shows a characteristic improvement over the synthetic drugs like acarbose (oral anti-diabetic drug) and captopril (standard antihypertensive drug) when, their IC50 values are compared. Lectin significantly inhibited α-glucosidase and α-amylase in a concentration dependent manner with IC50 values of 85.41 ± 1.21 ҝg/ml and 65.05 ± 1.2 µg/ml compared to acarbose having IC50 70.20 ± 0.47 value of µg/ml and 50.52 ± 1.01 µg/ml respectively. β-Carotene bleaching assay showed antioxidant activity of lectin (72.3%) to be as active as Butylated Hydroxylanisole (BHA). In addition, lectin demonstrated inhibition against ACE-I with IC50 value of 57.43 ± 1.20 µg/ml compared to captopril. Conclusion: Lectin demonstrated its antioxidant character, ACE-I inhibition and significantly inhibitory for α-glucosidase and α-amylase seems to qualify as an anti-hyperglycemic therapeutic molecule. The biological effects of chickpea lectin display potential for reducing the parameters of medically debilitating conditions. These characteristics however needs to be established under in vivo systems too viz. animals through to humans.

Methylmercury-induced pro-inflammatory cytokines activation and its preventive strategy using anti-inflammation N-acetyl-l-cysteine: a mini-review

2020 ◽  
Vol 35 (3) ◽  
pp. 233-238
Author(s):  
Muflihatul Muniroh
Keyword(s):  
Inflammatory Cytokines ◽  
Health Concern ◽  
Brain Cells ◽  
Preventive Strategy ◽  
Hearing Impairments ◽  
Sensory Disturbances ◽  
Anti Inflammation ◽  
Pro Inflammatory Cytokines

AbstractThe exposure of methylmercury (MeHg) has become a public health concern because of its neurotoxic effect. Various neurological symptoms were detected in Minamata disease patients, who got intoxicated by MeHg, including paresthesia, ataxia, gait disturbance, sensory disturbances, tremors, visual, and hearing impairments, indicating that MeHg could pass the blood-brain barrier (BBB) and cause impairment of neurons and other brain cells. Previous studies have reported some expected mechanisms of MeHg-induced neurotoxicity including the neuroinflammation pathway. It was characterized by the up-regulation of numerous pro-inflammatory cytokines expression. Therefore, the use of anti-inflammatories such as N-acetyl-l-cysteine (NAC) may act as a preventive compound to protect the brain from MeHg harmful effects. This mini-review will explain detailed information on MeHg-induced pro-inflammatory cytokines activation as well as possible preventive strategies using anti-inflammation NAC to protect brain cells, particularly in in vivo and in vitro studies.

scholarly journals A Review on the Medicinal and Pharmacological Properties of Traditional Ethnomedicinal Plant Sonapatha, Oroxylum indicum

Sinusitis ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 71-89
Author(s):  
Ganesh Chandra Jagetia
Keyword(s):  
Glucose Transporter ◽  
Skin Diseases ◽  
Regulatory Element ◽  
Experimental Studies ◽  
Fatty Acid Synthetase ◽  
Preclinical Models ◽  
Oroxylin A ◽  
Oroxylum Indicum

Oroxylum indicum, Sonapatha is traditionally used to treat asthma, biliousness, bronchitis, diarrhea, dysentery, fevers, vomiting, inflammation, leukoderma, skin diseases, rheumatoid arthritis, wound injury, and deworm intestine. This review has been written by collecting the relevant information from published material on various ethnomedicinal and pharmacological aspects of Sonapatha by making an internet, PubMed, SciFinder, Science direct, and Google Scholar search. Various experimental studies have shown that Sonapatha scavenges different free radicals and possesses alkaloids, flavonoids, cardio glycosides, tannins, sterols, phenols, saponins, and other phytochemicals. Numerous active principles including oroxylin A, chrysin, scutellarin, baicalein, and many more have been isolated from the different parts of Sonapatha. Sonapatha acts against microbial infection, cancer, hepatic, gastrointestinal, cardiac, and diabetic disorders. It is useful in the treatment of obesity and wound healing in in vitro and in vivo preclinical models. Sonapatha elevates glutathione, glutathione-s-transferase, glutathione peroxidase, catalase, and superoxide dismutase levels and reduces aspartate transaminase alanine aminotransaminase, alkaline phosphatase, lactate dehydrogenase, and lipid peroxidation levels in various tissues. Sonapatha activates the expression of p53, pRb, Fas, FasL, IL-12, and caspases and inhibited nuclear factor kappa (NF-κB), cyclooxygenase (COX-2), tumor necrosis factor (TNFα), interleukin (IL6), P38 activated mitogen-activated protein kinases (MAPK), fatty acid synthetase (FAS), sterol regulatory element-binding proteins 1c (SREBP-1c), proliferator-activated receptor γ2 (PPARγ2), glucose transporter (GLUT4), leptin, and HPV18 oncoproteins E6 and E7 at the molecular level, which may be responsible for its medicinal properties. The phytoconstituents of Sonapatha including oroxylin A, chrysin, and baicalein inhibit the replication of SARS-CoV-2 (COVID-19) in in vitro and in vivo experimental models, indicating its potential to contain COVID-19 infection in humans. The experimental studies in various preclinical models validate the use of Sonapatha in ethnomedicine and Ayurveda.

scholarly journals A small molecule HIF-1α stabilizer that accelerates diabetic wound healing

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guodong Li ◽  
Chung-Nga Ko ◽  
Dan Li ◽  
Chao Yang ◽  
Wanhe Wang ◽  
...  
Keyword(s):  
Wound Healing ◽  
Small Molecule ◽  
Hypoxia Inducible Factor ◽  
Diabetic Patients ◽  
Diabetic Mice ◽  
Impaired Wound Healing ◽  
Von Hippel Lindau ◽  
Design And Synthesis

AbstractImpaired wound healing and ulcer complications are a leading cause of death in diabetic patients. In this study, we report the design and synthesis of a cyclometalated iridium(III) metal complex 1a as a stabilizer of hypoxia-inducible factor-1α (HIF-1α). In vitro biophysical and cellular analyses demonstrate that this compound binds to Von Hippel-Lindau (VHL) and inhibits the VHL–HIF-1α interaction. Furthermore, the compound accumulates HIF-1α levels in cellulo and activates HIF-1α mediated gene expression, including VEGF, GLUT1, and EPO. In in vivo mouse models, the compound significantly accelerates wound closure in both normal and diabetic mice, with a greater effect being observed in the diabetic group. We also demonstrate that HIF-1α driven genes related to wound healing (i.e. HSP-90, VEGFR-1, SDF-1, SCF, and Tie-2) are increased in the wound tissue of 1a-treated diabetic mice (including, db/db, HFD/STZ and STZ models). Our study demonstrates a small molecule stabilizer of HIF-1α as a promising therapeutic agent for wound healing, and, more importantly, validates the feasibility of treating diabetic wounds by blocking the VHL and HIF-1α interaction.

scholarly journals Experimental Models of Hepatocellular Carcinoma—A Preclinical Perspective

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3651
Author(s):  
Alexandru Blidisel ◽  
Iasmina Marcovici ◽  
Dorina Coricovac ◽  
Florin Hut ◽  
Cristina Adriana Dehelean ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Mechanisms ◽  
Prediction Models ◽  
3D Models ◽  
Experimental Models ◽  
Health Concern ◽  
Liver Carcinoma ◽  
Tumor Type

Hepatocellular carcinoma (HCC), the most frequent form of primary liver carcinoma, is a heterogenous and complex tumor type with increased incidence, poor prognosis, and high mortality. The actual therapeutic arsenal is narrow and poorly effective, rendering this disease a global health concern. Although considerable progress has been made in terms of understanding the pathogenesis, molecular mechanisms, genetics, and therapeutical approaches, several facets of human HCC remain undiscovered. A valuable and prompt approach to acquire further knowledge about the unrevealed aspects of HCC and novel therapeutic candidates is represented by the application of experimental models. Experimental models (in vivo and in vitro 2D and 3D models) are considered reliable tools to gather data for clinical usability. This review offers an overview of the currently available preclinical models frequently applied for the study of hepatocellular carcinoma in terms of initiation, development, and progression, as well as for the discovery of efficient treatments, highlighting the advantages and the limitations of each model. Furthermore, we also focus on the role played by computational studies (in silico models and artificial intelligence-based prediction models) as promising novel tools in liver cancer research.

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