Lrp1 is essential for lethal Rift Valley fever hepatic disease in mice

Lipoprotein receptors: A little grease for enveloped viruses to open the lock?

Several studies recently highlighted the role of lipoprotein receptors in viral entry. These receptors are evolutionarily ancient proteins, key for the transport of lipids as well as other signaling molecules across the plasma membrane. Here, we discuss the different families of lipoprotein receptors and how they are hijacked by enveloped viruses to promote their entry into infected cells. While the usage of lipoprotein receptors was known for members of the Flaviviridae family and vesicular stomatitis virus, the last 4 years have seen the discovery that these receptors are used by many genetically unrelated viruses. We also emphasize how viral particles interact with these receptors and the possible targeting of these host factors as antiviral strategies.

Rift Valley Fever Virus Encephalitis: Viral and Host Determinants of Pathogenesis

Rift Valley fever virus (RVFV) is a mosquito-borne virus endemic to Africa and the Middle East. RVFV infection can cause encephalitis, which is associated with significant morbidity and mortality. Studies of RVFV encephalitis following percutaneous inoculation, as would occur following a mosquito bite, have historically been limited by a lack of consistent animal models. In this review, we describe new insights into the pathogenesis of RVFV and the opportunities provided by new mouse models. We underscore the need to consider viral strain and route of inoculation when interpreting data obtained using animal models. We discuss the trafficking of RVFV and the role of host genetics and immunity in modulating the pathogenesis of RVFV encephalitis. We also explore potential strategies to prevent and treat central nervous system disease caused by RVFV and discuss remaining knowledge gaps.

Rift Valley Fever

Rift Valley fever (RVF) is a zoonotic viral disease that affects domestic and wild ruminants such as cattle, sheep, goats, camels, and buffaloes. Rift valley fever virus (RVFV), the causative agent of RVF, can also infect humans. RVFV is an arthropod-borne virus (arbovirus) that is primarily spread through the bites of infected mosquitoes or exposure to infected blood. RVFV was first isolated and characterized in the Rift Valley of Kenya in 1931 and is endemic throughout sub-Saharan Africa, including Comoros and Madagascar, the Arabian Peninsula (Saudi Arabia and Yemen), and Mayotte.

An Introduction to Rift Valley Fever Virus

Rift Valley fever virus (RVFV) is a pathogen transmitted to humans and livestock via mosquito bites. This virus, which was discovered in Kenya in 1930, is considered by the World Health Organization (WHO) and the World Organisation for Animal Health (WOAH) to be associated with a high risk of causing large-scale epidemics. However, means dedicated to fighting RVFV have been limited, and despite recent research efforts, the virus remains poorly understood at both the molecular and cellular levels as well as at a broader scale of research in the field and in animal and human populations. In this introductory chapter of a methods book, we aim to provide readers with a concise overview of RVFV, from its ecology and transmission to the structural and genomic organization of virions and its life cycle in host cells.

Laboratory Animal Models for Rift Valley Fever Virus Disease

Rift Valley fever virus (RVFV) is an arboviral pathogen of clinical and agricultural relevance. The ongoing development of targeted RVFV prophylactics and therapeutics is overwhelmingly dependent on animal models due to both natural, that is, sporadic outbreaks, and structural, for example, underresourcing of endemic regions, limitations in accessing human patient samples and cohorts. Elucidating mechanisms of viral pathogenesis and testing therapeutics is further complicated by the diverse manifestations of RVFV disease and the heterogeneity of the host response to infection. In this chapter, we describe major clinical manifestations of RVFV infection and discuss the laboratory animal models used to study each.

Making Rift Valley Fever Viral Particles Fluorescent

Rift Valley fever virus (RVFV) is a mosquito-borne pathogen that represents a significant threat to both human and veterinary public health. Since its discovery in the Great Rift Valley of Kenya in the 1930s, the virus has spread across Africa and beyond, now posing a risk of introduction into Southern Europe and Asia. Despite recent progresses, early RVFV-host cell interactions remain largely uncharacterized. In this method chapter, we delineate the procedure for labeling RVFV particles with fluorescent organic dyes. This approach makes it feasible to visualize single viral particles in both fixed and living cells and study RVFV entry into host cells. We provide additional examples with two viruses closely related to RVFV, namely, Toscana virus and Uukuniemi virus. Furthermore, we illustrate how to utilize fluorescent viral particles to examine and quantify each step of the cell entry program of RVFV, which includes state-of-the-art fluorescence-based detection techniques such as fluorescence microscopy, flow cytometry, and fluorimetry.

Host entry factors of Rift Valley Fever Virus infection

Rift Valley Fever Virus (RVFV) is a negative sense segmented RNA virus that can cause severe hemorrhagic fever. The tri-segmented virus genome encodes for six (6) multifunctional proteins that engage host factors at a variety of different stages in the replication cycle. The S segment encodes nucleoprotein (N) and nonstructural protein S (NSs), the M segment encodes viral glycoproteins Gn and Gc as well as nonstructural protein M (NSm) and the L segment encodes the viral polymerase (L). Viral glycoproteins Gn and Gc are responsible for entry by binding to a number of host factors. Our recent studies identified a scavenger receptor, LDL receptor related protein 1 (Lrp1), as a potential pro-viral host factor for RVFV and related viruses, including Oropouche virus (OROV) infection. Coincidentally, several recent studies identified other LDL family proteins as viral entry factors and receptors for other viral families. Collectively, these observations suggest that highly conserved LDL family proteins may play a significant role in facilitating entry of viruses from several distinct families. Given the significant roles of viral and host factors during infection, characterization of these interactions is critical for therapeutic targeting with neutralizing antibodies and vaccines.