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20 Publications visible to you, out of a total of 20

Abstract (Expand)

Medium-chain antimicrobial lipids are promising antiviral agents to inhibit membrane-enveloped viruses such as African swine fever virus (ASFV) and influenza A virus (IAV) in livestock applications. However, current uses are limited to feed pathogen mitigation due to low aqueous solubility and the development of water-dispersible lipid formulations is needed for broader application usage. In this study, we report a water-dispersible antimicrobial lipid mixture of monoglycerides and lactylates that can inhibit ASFV and IAV and exhibits antiviral properties in drinking water and feed matrices. The lipid mixture reduced the viral infectivity of membrane-enveloped ASFV and IAV in aqueous solution in a dose-dependent manner but was inactive against non-enveloped encephalomyocarditis virus (EMCV). Additional ASFV experiments supported that the lipid mixture is virucidal, which was corroborated by polymerase chain reaction (PCR) experiments. Feed mitigation experiments demonstrated that the lipid mixture can also inhibit ASFV infectivity and affected the conformational properties of ASFV p72 structural protein in virus-spiked feed. Mechanistic experiments identified that the lipid mixture rapidly disrupted phospholipid membranes in a micelle-dependent manner, which aligns with the virological data while higher concentrations were needed for virucidal activity than for the onset of membrane disruption. These findings support that water-dispersible antimicrobial lipid mixtures can effectively inhibit ASFV and IAV and have practical advantages for drinking water applications compared to existing medium-chain antimicrobial lipid mitigant options that are formulated as dry powders or oils for in-feed applications.

Authors: Joshua A Jackman, Roza Izmailyan, Rafayela Grigoryan, Tun Naw Sut, Abel Taye, Hovakim Zakaryan, Charles C Elrod

Date Published: 25th Dec 2024

Publication Type: Journal

Abstract (Expand)

African swine fever virus (ASFV) is a major threat to pig production and the lack of effective vaccines underscores the need to develop robust antiviral countermeasures. Pathologically, a significant elevation in pro-inflammatory cytokine production is associated with ASFV infection in pigs and there is high interest in identifying dual-acting natural compounds that exhibit antiviral and anti-inflammatory activities.

Authors: Joshua A Jackman, Astghik Hakobyan, Rafayela Grigoryan, Roza Izmailyan, Charles C Elrod, Hovakim Zakaryan

Date Published: 25th Apr 2024

Publication Type: Journal

Abstract (Expand)

Naturally abundant antimicrobial lipids, such as fatty acids and monoglycerides, that disrupt membrane-enveloped viruses are promising mitigants to inhibit African swine fever virus (ASFV). Among mitigant candidates in this class, glycerol monolaurate (GML) has demonstrated particularly high antiviral activity against laboratory-adapted ASFV strains. However, there is an outstanding need to further determine the effects of GML on wild-type ASFV strains, which can have different virulence levels and sensitivities to membrane-disrupting compounds as compared to laboratory-adapted strains. Herein, we investigated the antiviral effects of GML on a highly virulent strain of a wild-type ASFV isolate (Armenia/07) in an in vitro porcine macrophage model. GML treatment caused a concentration-dependent reduction in viral infectivity, and there was a sharp transition between inactive and active GML concentrations. Low GML concentrations had negligible effect on viral infectivity, whereas sufficiently high GML concentrations caused a >99% decrease in viral infectivity. The concentration onset of antiviral activity matched the critical micelle concentration (CMC) value of GML, reinforcing that GML micelles play a critical role in enabling anti-ASFV activity. These findings validate that GML can potently inhibit wild-type ASFV infection of porcine macrophages and support a biophysical explanation to guide antimicrobial lipid performance optimization for pathogen mitigation applications.

Authors: Joshua A Jackman, Erik Arabyan, Hovakim Zakaryan, Charles C Elrod

Date Published: 25th Sep 2023

Publication Type: Journal

Abstract (Expand)

African swine fever virus (ASFV) is a double-stranded DNA virus that causes an acute and hemorrhagic disease in domestic swine, resulting in significant economic losses to the global porcine industry. The lack of vaccines and antiviral drugs highlights the urgent need for antiviral studies against ASFV. Here, we report that brequinar (BQR), which is a specific inhibitor of dihydroorotate dehydrogenase, robustly inhibits ASFV replication in Vero cells, as well as in porcine macrophages. We demonstrate that BQR exerts its antiviral activity in a dose-dependent manner through the depletion of pyrimidine pool. Although BQR does not affect the synthesis of an early viral protein, pI215L, the synthesis of late viral proteins, p17 and p72, is suppressed in the presence of BQR. We also show that BQR is able to induce cellular antiviral response in ASFV-infected macrophages by enhancing the expression of interferon-stimulated genes. Taken together, our study reveals that targeting nucleotide biosynthesis represents a promising strategy for developing antiviral agents against ASFV.

Authors: Rafayela Grigoryan, Erik Arabyan, Roza Izmailyan, Zaven Karalyan, Nuno Jordão, Fernando Ferreira, Hovakim Zakaryan

Date Published: 23rd May 2022

Publication Type: Journal

Abstract (Expand)

Naturally occurring plant flavonoids are a promising class of antiviral agents to inhibit African swine fever virus (ASFV), which causes highly fatal disease in pigs and is a major threat to the swine industry. Currently known flavonoids with anti-ASFV activity demonstrate a wide range of antiviral mechanisms, which motivates exploration of new antiviral candidates within this class. The objective of this study was to determine whether other flavonoids may significantly inhibit ASFV infection <i>in vitro</i>. We performed a cell-based library screen of 90 flavonoids. Our screening method allowed us to track the development of virus-induced cytopathic effect by MTT in the presence of tested flavonoids. This screening method was shown to be robust for hit identification, with an average Z-factor of 0.683. We identified nine compounds that inhibit ASFV Ba71V strain in Vero cells. Among them, kaempferol was the most potent and exhibited dose-dependent inhibition, which occurred through a virostatic effect. Time-of-addition studies revealed that kaempferol acts on the entry and post-entry stages of the ASFV replication cycle and impairs viral protein and DNA synthesis. It was further identified that kaempferol induces autophagy in ASFV-infected Vero cells, which is related to its antiviral activity and could be partially abrogated by the addition of an autophagy inhibitor. Kaempferol also exhibited dose-dependent inhibition of a highly virulent ASFV Arm/07 isolate in porcine macrophages. Together, these findings support that kaempferol is a promising anti-ASFV agent and has a distinct antiviral mechanism compared to other anti-ASFV flavonoids.

Authors: Erik Arabyan, Astghik Hakobyan, Tamara Hakobyan, Rafaella Grigoryan, Roza Izmailyan, Aida Avetisyan, Zaven Karalyan, Joshua A Jackman, Fernando Ferreira, Charles C Elrod, Hovakim Zakaryan

Date Published: 21st Oct 2021

Publication Type: Journal

Abstract (Expand)

The ongoing African swine fever virus (ASFv) epidemic has had a major impact on pig production globally and biosecurity efforts to curb ASFv infectivity and transmission are a high priority. It has been recently identified that feed and feed ingredients, along with drinking water, can serve as transmission vehicles and might facilitate transboundary spread of ASFv. Thus, it is important to test the antiviral activity of regulatory compatible, antiviral feed additives that might inhibit ASFv infectivity in feed. One promising group of feed additive candidates includes medium-chain fatty acids (MCFA) and monoglyceride derivatives, which are known to disrupt the lipid membrane surrounding certain enveloped viruses and bacteria.

Authors: Joshua A Jackman, Astghik Hakobyan, Hovakim Zakaryan, Charles C Elrod

Date Published: 8th Dec 2020

Publication Type: Journal

Abstract (Expand)

African swine fever virus (ASFV) is a significant transboundary virus that continues to spread outside Africa in Europe and most recently to China, Vietnam and Cambodia. Pigs infected with highly virulent ASFV develop a hemorrhagic fever like illness with high lethality reaching up to 100%. There are no vaccines or antiviral drugs available for the prevention or treatment of ASFV infections. We here review molecules that have been reported to inhibit ASFV replication, either as direct-acting antivirals or host-targeting drugs as well as those that act via a yet unknown mechanism. Prospects for future antiviral research against ASFV are also discussed.

Authors: Erik Arabyan, Armen Kotsynyan, Astghik Hakobyan, Hovakim Zakaryan

Date Published: 17th Jul 2019

Publication Type: Journal

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