Role of AMPK in herpes simplex virus type 1 replication in endothelial cells

Systemic distribution of viral pathogens often requires the interaction of viruses with cells of the vascular system, of which endothelial cells are an indispensable part. One such virus is the Herpes simplex virus type 1 (HSV-1). HSV-1 is a highly contagious ubiquitous pathogen, which commonly causes blisters or cold sores, but may play an important role in the development of Alzheimer's disease, severe septic processes as well as atherosclerosis. Since no virus-specific vaccine is available to prevent HSV-1 infections, the identification of host cell proteins, which are involved in HSV-1 replication, and the modulation of their activity might be a promising aim to develop future antiviral therapies and one such candidate could be AMP-activated protein kinase (AMPK), known to be the master regulator of cellular pathways. To gain insights into the role of AMPK in HSV-1 replication, human umbilical vein endothelial cells were infected with HSV-1 and alterations caused by this infection were examined. Our data demonstrated that HSV-1 replicates in endothelial cells and HSV-1 infection led to alteration of various signaling pathways. The Akt/mTORC1 pathway is important for viral replication. We showed that HSV-1 replication is controlled by AMPK, an increase in viral concentration is observed in AMPK knockdown and knockout cells and, on the other hand, a decrease in viral concentrations is seen in cells treated with AMPK activators. Our results lead us to direct the protective role of AMPK through metabolic pathways. AMPK activation inhibits fatty acid synthesis and cholesterol biosynthesis and this could be the mechanism for its antiviral role in endothelial cells. Our data indicates a protective role of AMPK against HSV-1 replication in endothelial cells via inhibition of metabolic pathways. This data could pave way for developing antiviral strategies using AMPK, a host cell protein which, according to the current global situation is a need of the hour

AMPK protects endothelial cells against HSV-1 replication via inhibition of mTORC1 and ACC1

Herpes simplex virus type 1 (HSV-1) is a widespread contagious pathogen, mostly causing mild symptoms on the mucosal entry side. However, systemic distribution, in particular upon reactivation of the virus in immunocompromised patients, may trigger an innate immune response and induce damage of organs. In these conditions, HSV-1 may infect vascular endothelial cells, but little is known about the regulation of HSV-1 replication and possible defense mechanisms in these cells. The current study addresses the question of whether the host cell protein AMP-activated protein kinase (AMPK), an important metabolic sensor, can control HSV-1 replication in endothelial cells. We show that downregulation of the catalytic subunits AMPKα1 and/or AMPKα2 increased HSV-1 replication as monitored by TCID50 titrations, while a potent AMPK agonist, MK-8722, strongly inhibited it. MK-8722 induced a persistent phosphorylation of the AMPK downstream targets acetyl-CoA carboxylase (ACC) and the rapamycin-sensitive adaptor protein of mTOR (Raptor) and, related to this, impairment of ACC1-mediated lipid synthesis and the mechanistic target of the rapamycin complex-1 (mTORC1) pathway. Since blockade of mTOR by Torin-2 as well as downregulation of ACC1 by siRNA also decreased HSV-1 replication, MK-8722 is likely to exert its anti-viral effect via mTORC1 and ACC1 inhibition. Importantly, MK-8722 was able to reduce virus replication even when added after HSV-1. Together, our data highlight the importance of endothelial cells as host cells for HSV-1 replication upon systemic infection and identify AMPK, a metabolic host cell protein, as a potential target for antiviral strategies against HSV-1 infection and its severe consequences

D,L-Lysine-Acetylsalicylate + Glycine (LASAG) Reduces SARS-CoV-2 Replication and Shows an Additive Effect with Remdesivir

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease-19 (COVID-19) is still challenging healthcare systems and societies worldwide. While vaccines are available, therapeutic strategies are developing and need to be adapted to each patient. Many clinical approaches focus on the repurposing of approved therapeutics against other diseases. However, the efficacy of these compounds on viral infection or even harmful secondary effects in the context of SARS-CoV-2 infection are sparsely investigated. Similarly, adverse effects of commonly used therapeutics against lifestyle diseases have not been studied in detail. Using mono cell culture systems and a more complex chip model, we investigated the effects of the acetylsalicylic acid (ASA) salt D,L-lysine-acetylsalicylate + glycine (LASAG) on SARS-CoV-2 infection in vitro. ASA is commonly known as Aspirin ® and is one of the most frequently used medications worldwide. Our data indicate an inhibitory effect of LASAG on SARS-CoV-2 replication and SARS-CoV-2-induced expression of pro-inflammatory cytokines and coagulation factors. Remarkably, our data point to an additive effect of the combination of LASAG and the antiviral acting drug remdesivir on SARS-CoV-2 replication in vitro