Hepatitis C virus alters the morphology and function of peroxisomes

Peroxisomes are underappreciated organelles hijacked by viruses

Peroxisomes are cellular organelles that are crucial for metabolism, stress responses, and healthy aging. They have recently come to be considered as important mediators of the immune response during viral infections. Consequently, various viruses target peroxisomes for the purpose of hijacking either their biogenesis or their functions, as a means of replicating efficiently, making this a compelling research area. Despite their known connections with mitochondria, which have been the object of considerable research on account of their role in the innate immune response, less is known about peroxisomes in this context. In this review, we explore the evolving understanding of the role of peroxisomes, highlighting recent findings on how they are exploited by viruses to modulate their replication cycle.

Virucidal activity of porphyrin-based metal-organic frameworks against highly pathogenic coronaviruses and hepatitis C virus

The antiviral effect of four porphyrin-based Metal-Organic Frameworks (PMOFs) with Al and Zr, namely Al-TCPP, PCN-222, PCN-223 and PCN-224 was assessed for the first time against HCoV-229E, two highly pathogenic coronaviruses (SARS-CoV-2 and MERS-CoV) and hepatitis C virus (HCV). Infection tests in vitro were done under dark or light exposure for different contact times, and it was found that 15 min of light exposure were enough to give antiviral properties to the materials, therefore inactivating HCoV-229E by 99.98 % and 99.96 % for Al-TCPP and PCN-222. Al-TCPP diminished the viral titer of SARS-CoV-2 greater than PCN-222 in the same duration of light exposure, having an effect of 99.95 % and 93.48 % respectively. Next, Al-TCPP was chosen as the best candidate possessing antiviral properties and was tested against MERS-CoV and HCV, showcasing a reduction of infectivity of 99.28 % and 98.15 % respectively for each virus. The mechanism of the antiviral activity of the four PMOFs was found to be the production of singlet oxygen 1O2 from the porphyrin ligand TCPP when exposed to visible light, by using sodium azide (NaN3) as a scavenger, that can later attack the phospholipids on the envelope of the viruses, thus preventing their entry into the cells.

Viral regulation of organelle membrane contact sites

At the core of organelle functions lies their ability and need to form dynamic organelle-organelle networks that drive intracellular communication and coordination of cellular pathways. These networks are facilitated by membrane contact sites (MCSs) that promote both intra-organelle and inter-organelle communication. Given their multiple functions, MCSs and the proteins that form them are commonly co-opted by viruses during infection to promote viral replication. This Essay discusses mechanisms acquired by diverse human viruses to regulate MCS functions in either proviral processes or host defense. It also examines techniques used for examining MCSs in the context of viral infections.

The peroxisome: an update on mysteries 3.0

Peroxisomes are highly dynamic, oxidative organelles with key metabolic functions in cellular lipid metabolism, such as the β-oxidation of fatty acids and the synthesis of myelin sheath lipids, as well as the regulation of cellular redox balance. Loss of peroxisomal functions causes severe metabolic disorders in humans. Furthermore, peroxisomes also fulfil protective roles in pathogen and viral defence and immunity, highlighting their wider significance in human health and disease. This has sparked increasing interest in peroxisome biology and their physiological functions. This review presents an update and a continuation of three previous review articles addressing the unsolved mysteries of this remarkable organelle. We continue to highlight recent discoveries, advancements, and trends in peroxisome research, and address novel findings on the metabolic functions of peroxisomes, their biogenesis, protein import, membrane dynamics and division, as well as on peroxisome-organelle membrane contact sites and organelle cooperation. Furthermore, recent insights into peroxisome organisation through super-resolution microscopy are discussed. Finally, we address new roles for peroxisomes in immune and defence mechanisms and in human disorders, and for peroxisomal functions in different cell/tissue types, in particular their contribution to organ-specific pathologies.

Peroxisomal hydrogen peroxide signaling: A new chapter in intracellular communication research

Hydrogen peroxide (H2O2), a natural metabolite commonly found in aerobic organisms, plays a crucial role in numerous cellular signaling processes. One of the key organelles involved in the cell's metabolism of H2O2 is the peroxisome. In this review, we first provide a concise overview of the current understanding of H2O2 as a molecular messenger in thiol redox signaling, along with the role of peroxisomes as guardians and modulators of cellular H2O2 balance. Next, we direct our focus toward the recently identified primary protein targets of H2O2 originating from peroxisomes, emphasizing their importance in unraveling the complex interplay between peroxisomal H2O2 and cell signaling. We specifically focus on three areas: signaling through peroxiredoxin redox relay complexes, calcium signaling, and phospho-signaling. Finally, we highlight key research directions that warrant further investigation to enhance our comprehension of the molecular and biochemical mechanisms linking alterations in peroxisomal H2O2 metabolism with disease.

The diverse roles of peroxisomes in the interplay between viruses and mammalian cells

Peroxisomes are ubiquitous organelles found in eukaryotic cells that play a critical role in the oxidative metabolism of lipids and detoxification of reactive oxygen species (ROS). Recently, the role of peroxisomes in viral infections has been extensively studied. Although several studies have reported that peroxisomes exert antiviral activity, evidence indicates that viruses have also evolved diverse strategies to evade peroxisomal antiviral signals. In this review, we summarize the multiple roles of peroxisomes in the interplay between viruses and mammalian cells. Focus is given on the peroxisomal regulation of innate immune response, lipid metabolism, ROS production, and viral regulation of peroxisomal biosynthesis and degradation. Understanding the interactions between peroxisomes and viruses provides novel insights for the development of new antiviral strategies.