The Asian Games, Air Pollution and Birth Outcomes in South China: An Instrumental Variable Approach

We estimate the causal effects of air pollution exposure on low birthweight, birthweight, and prematurity risk in South China, for all expectant mothers and by maternal age group and child sex. We do so by exploiting exogenous improvement in air quality during the 2010 Guangzhou Asian Games, when strict regulations were mandated to assure better air quality. We use daily air pollution levels collected from monitoring stations in Guangzhou, the Asian Games host city, and Shenzhen, a nearby control city, between 2009 and 2011. We first show that air quality during the Asian Games significantly improved in Guangzhou, relative to Shenzhen. Further, using birth-certificate data for both cities for 2009 to 2011 and using expected pregnancy overlap with the Asian Games as an instrumental variable, we study the effects of three pollutants (PM10, SO2, NO2) on birth outcomes. Results show that 1) air pollutants significantly reduced average birthweight and increased preterm risk; 2) for birthweight, late pregnancy is most sensitive to PM10 exposure, but there is not consistent evidence of a sensitive period for other pollutants and outcomes; 3) for birthweight, babies of mothers who are at least 35 years old show more vulnerability to all three air pollutants; and 4) male babies show more vulnerability than female babies to PM10 and SO2, but birthweights of female babies are more sensitive than those of male babies to NO2

cGAS-STING effectively restricts murine norovirus infection but antagonizes the antiviral action of N-terminus of RIG-I in mouse macrophages

Although cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling has been well recognized in defending DNA viruses, the role of cGAS-STING signaling in regulating infection of RNA viruses remains largely elusive. Noroviruses, as single-stranded RNA viruses, are the main causative agents of acute viral gastroenteritis worldwide. This study comprehensively investigated the role of cGAS-STING in response to murine norovirus (MNV) infection. We found that STING agonists potently inhibited MNV replication in mouse macrophages partially requiring the JAK/STAT pathway that induced transcription of interferon (IFN)-stimulated genes (ISGs). Loss- and gain-function assays revealed that both cGAS and STING were necessary for host defense against MNV propagation. Knocking out cGAS or STING in mouse macrophages led to defects in induction of antiviral ISGs upon MNV infection. Overexpression of cGAS and STING moderately increased ISG transcription but potently inhibited MNV replication in human HEK293T cells ectopically expressing the viral receptor CD300lf. This inhibitory effect was not affected by JAK inhibitor treatment or expression of different MNV viral proteins. Interestingly, STING but not cGAS interacted with mouse RIG-I, and attenuated its N-terminus-mediated anti-MNV effects. Our results implicate an essential role for mouse cGAS and STING in regulating innate immune response and defending MNV infection. This further strengthens the evidence of cGAS-STING signaling in response to RNA virus infection

A simplified qPCR method revealing tRNAome remodeling upon infection by genotype 3 hepatitis E virus

The landscape of tRNA–viral codons regulates viral adaption at the translational level, presumably through adapting to host codon usage or modulating the host tRNAome. We found that the major zoonotic genotype of hepatitis E virus (HEV) has not adapted to host codon usage, prompting exploration of the effects of HEV infection on the host tRNAome. However, tRNAome quantification is largely impeded by the extremely short sequences of tRNAs and redundancy of tRNA genes. Here, we present a length-extension and stepwise simplified qPCR method that utilizes a universal DNA/RNA hybrid tRNA adaptor and degenerate primers. Using this novel methodology, we observe that HEV infection dramatically reprograms the hepatic tRNAome, which is likely to facilitate translation of viral RNAs. This tRNAome quantification method bears broad implications for future tRNA research and possibly tRNA-based diagnostics

Ivermectin effectively inhibits hepatitis E virus replication, requiring the host nuclear transport protein importin α1

We show that ivermectin, an FDA-approved anti-parasitic drug, effectively inhibits infection with hepatitis E virus (HEV) genotypes 1 and 3 in a range of cell culture models, including hepatic and extrahepatic cells. Long-term treatment showed no clear evidence of the development of drug resistance. Gene silencing of importin-α1, a cellular target of ivermectin and a key member of the host nuclear transport complex, inhibited viral replication and largely abolished the anti-HEV effect of ivermectin.</p

Ivermectin effectively inhibits hepatitis E virus replication, requiring the host nuclear transport protein importin α1

We show that ivermectin, an FDA-approved anti-parasitic drug, effectively inhibits infection with hepatitis E virus (HEV) genotypes 1 and 3 in a range of cell culture models, including hepatic and extrahepatic cells. Long-term treatment showed no clear evidence of the development of drug resistance. Gene silencing of importin-α1, a cellular target of ivermectin and a key member of the host nuclear transport complex, inhibited viral replication and largely abolished the anti-HEV effect of ivermectin.</p

Lipid droplets and their interactions with other organelles in liver diseases

Lipid droplets are cellular organelles used for lipid storage with a hydrophobic core of neutral lipids enclosed by a phospholipid monolayer. Besides presenting as giant single organelles in fat tissue, lipid droplets are also widely present as a multitude of small structures in hepatocytes, where they play key roles in health and disease of the liver. In addition to lipid storage, lipid droplets are also directly involved in lipid metabolism, membrane biosynthesis, cell signaling, inflammation, pathogen-host interaction and cancer development. In addition, they interact with other cellular organelles to regulate cellular biology. It is fair to say that the exact functions of lipid droplets in cellular physiology remain largely obscure. Thus prompted, here we aim to analyze the corpus of contemporary biomedical literature to create a framework as to how the role of lipid droplets in hepatocyte physiology and pathophysiology should be understood. The resulting framework should help understanding the interaction of lipid droplets with other organelles in important liver diseases, including fatty liver disease, viral hepatitis and liver cancer and direct further research directions

Recombinant identification, molecular classification and proposed reference genomes for hepatitis delta virus

Hepatitis delta virus (HDV), as a defective sub-virus that co-infects with hepatitis B virus, imposes an emerging global health burden. However, genetic characteristics and molecular classification of HDV remain under investigated. In this study, we have systematically retrieved and analysed a large set of HDV full-length genome sequences and identified novel recombinants. Based on phylogenetic and genetic analyses, we have established an updated classification system for HDV when recombinants were excluded. Furthermore, we have mapped the global distribution of different genotypes and subtypes. Finally, we have compiled a complete set of reference genomes for each subtype and proposed criteria for future identification of novel genotypes and subtypes. Of note, the global distribution map indicates that currently available HDV genetic data remain limited, and thus our proposed classification will likely evolve as future epidemiological data will accumulate. These results will facilitate the future research on the diagnosis, screening, epidemiology, evolution, prevention and clinical management of HDV infection