The Autophagy Protein ATG16L1 Is Required for Sindbis Virus-Induced eIF2α Phosphorylation and Stress Granule Formation

Galectin-7 promotes cisplatin efficacy by facilitating apoptosis and G3BP1 degradation in cervical cancer

The emergence of chemoresistance in cervical cancer is extremely challenging in chemotherapy. Oxidative stress has emerged as the regulatory factor in drug resistance, but the detailed mechanism is still unknown. Stress granules, are membrane-less ribonucleoprotein-based condensates, could enhance chemoresistance by sequestering proapoptotic proteins inhibition of cell death upon exposure to drug-induced oxidative stress. Galectin-7, a member of galectin family, exerts varied roles in tumor repression or progression in different cancers. However, its role in cervical cancer has not been sufficiently studied. Here, we found that galectin-7 promotes cisplatin (CDDP) induced apoptosis and associates with stress granule-nucleating protein G3BP1 degradation. With the treatment of cisplatin, galectin-7 could enhance apoptosis by upregulating cleaved-PARP1 and the generation of reactive oxygen species (ROS), promoting mitochondrial fission, and reducing mitochondrial membrane potential (MMP). Furthermore, galectin-7 also reduces resistance by facilitating cisplatin-induced stress granules clearance through galectin-7/RACK1/G3BP1 axis. All these data suggested that galectin-7 promotes cisplatin sensitivity, and it would be potential target for potentiating efficacy in cervical cancer chemotherapy.

The potential importance of autophagy genes expression profile dysregulation and ATG polymorphisms in COVID-19 pathogenesis

Autophagy is one of the important mechanisms in cell maintenance, which is considered associated with different pathological conditions such as viral infections. In this current study, the expression level and polymorphisms in some of the most important genes in the autophagy flux in COVID-19 patients were evaluated. This cross-sectional study was conducted among 50 confirmed COVID-19 patients and 20 healthy controls. The COVID-19 patients were divided into a severe group and a mild group according to their clinical features. The expression levels of ATG5, ATG16L1, LC3, and BECN1 were evaluated by the 2^-∆∆CT method and beta-actin as the internal control. The polymorphisms of the ATG5 (rs506027, rs510432) and ATG16L1 (rs2241880 or T300A) were evaluated by the Sanger sequencing following the conventional PCR. The mean age of the included patients was 58.3 ± 17.9 and 22 (44%) were female. The expression levels of the LC3 were downregulated, while BECN1 and ATG16L1 genes represent an upregulation in COVID-19 patients. The polymorphism analysis revealed the ATG16L1 rs2241880 and AGT5 rs506027 polymorphism frequencies are statistically significantly different between COVID-19 and Healthy controls. The autophagy alteration represents an association with COVID-19 pathogenesis and severity. The current study is consistent with the alteration of autophagy elements in COVID-19 patients by mRNA expression-level evaluation. Furthermore, ATG16L1 rs2241880 and AGT5 rs506027 polymorphisms seem to be important in COVID-19 and are highly suggested for further investigations.

Stress granules: potential therapeutic targets for infectious and inflammatory diseases

Eukaryotic cells are stimulated by external pressure such as that derived from heat shock, oxidative stress, nutrient deficiencies, or infections, which induce the formation of stress granules (SGs) that facilitates cellular adaptation to environmental pressures. As aggregated products of the translation initiation complex in the cytoplasm, SGs play important roles in cell gene expression and homeostasis. Infection induces SGs formation. Specifically, a pathogen that invades a host cell leverages the host cell translation machinery to complete the pathogen life cycle. In response, the host cell suspends translation, which leads to SGs formation, to resist pathogen invasion. This article reviews the production and function of SGs, the interaction between SGs and pathogens, and the relationship between SGs and pathogen-induced innate immunity to provide directions for further research into anti-infection and anti-inflammatory disease strategies.

Multiple functions of stress granules in viral infection at a glance

Stress granules (SGs) are distinct RNA granules induced by various stresses, which are evolutionarily conserved across species. In general, SGs act as a conservative and essential self-protection mechanism during stress responses. Viruses have a long evolutionary history and viral infections can trigger a series of cellular stress responses, which may interact with SG formation. Targeting SGs is believed as one of the critical and conservative measures for viruses to tackle the inhibition of host cells. In this systematic review, we have summarized the role of SGs in viral infection and categorized their relationships into three tables, with a particular focus on Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Moreover, we have outlined several kinds of drugs targeting SGs according to different pathways, most of which are potentially effective against SARS-CoV-2. We believe this review would offer a new view for the researchers and clinicians to attempt to develop more efficacious treatments for virus infection, particularly for the treatment of SARS-CoV-2 infection.

The Multifunctional Faces of T-Cell Intracellular Antigen 1 in Health and Disease

T-cell intracellular antigen 1 (TIA1) is an RNA-binding protein that is expressed in many tissues and in the vast majority of species, although it was first discovered as a component of human cytotoxic T lymphocytes. TIA1 has a dual localization in the nucleus and cytoplasm, where it plays an important role as a regulator of gene-expression flux. As a multifunctional master modulator, TIA1 controls biological processes relevant to the physiological functioning of the organism and the development and/or progression of several human pathologies. This review summarizes our current knowledge of the molecular aspects and cellular processes involving TIA1, with relevance for human pathophysiology.

Systematic identification of autophagy-related proteins in Aedes albopictus

Autophagy is a conserved cellular process playing a role in maintenance of cellular homeostasis and response to changing nutrient conditions via degradation and recirculation of cellular redundant components. Autophagy-related proteins (Atg) play important function in autophagy pathway. Aedes albopictus mosquito is an effective vector transmitting multiple viruses which cause serious human diseases. Moreover, Aedes albopictus mosquito is becoming a serious threat to human health due to its widening distribution in recent years and thus worth of more research attention. It was reported that autophagy might play a role in viral infection in Aedes mosquito. To better understand the interaction between autophagy and arbovirus infection in mosquito system, it is necessary to identify autophagy pathway in the system. However, autophagy in Aedes albopictus mosquito is still poorly understood so far. We recently identified AaAtg8, the first Atg protein reported in Aedes albopictus mosquito. This work further identified twelve atg genes in Aedes albopictus mosquito. Sequence and phylogenetic analysis of the twelve atg genes were performed. Expression profiles of all the twelve Aaatg genes in different developmental stages and genders of Aedes albopictus mosquito were conducted. Effects of chemicals inhibiting or inducing autophagy on the levels of eight identified AaAtg proteins were examined. The function of two identified AaAtg proteins AaAtg6 and AaAtg16 and their response to arbovirus SINV infection were studied preliminarily. Taken together, this work systematically identified Aedes albopictus atg genes and provided basic information which might help to elucidate the autophagy pathway and the role of autophagy in arbovirus infection in Aedes mosquito system.

AR12 (OSU-03012) suppresses GRP78 expression and inhibits SARS-CoV-2 replication

AR12 is a derivative of celecoxib which no-longer acts against COX2 but instead inhibits the ATPase activity of multiple chaperone proteins, in particular GRP78. GRP78 acts as a sensor of endoplasmic reticulum stress and is an essential chaperone required for the life cycle of all mammalian viruses. We and others previously demonstrated in vitro and in vivo that AR12 increases autophagosome formation and autophagic flux, enhances virus protein degradation, preventing virus reproduction, and prolonging the survival of infected animals. In this report, we determined whether AR12 could act against SARS-CoV-2. In a dose-dependent fashion AR12 inhibited SARS-CoV-2 spike protein expression in transfected or infected cells. AR12 suppressed the production of infectious virions via autophagosome formation, which was also associated with degradation of GRP78. After AR12 exposure, the colocalization of GRP78 with spike protein was reduced. Knock down of eIF2α prevented AR12-induced spike degradation and knock down of Beclin1 or ATG5 caused the spike protein to localize in LAMP2+ vesicles without apparent degradation. HCT116 cells expressing ATG16L1 T300, found in the majority of persons of non-European descent, particularly from Africa, expressed greater amounts of GRP78 and SARS-CoV-2 receptor angiotensin converting enzyme 2 compared to ATG16L1 A300, predominantly found in Europeans, suggestive that ATG16L1 T300 expression may be associated with a greater ability to be infected and to reproduce SARS-CoV-2. In conclusion, our findings demonstrate that AR12 represents a clinically relevant anti-viral drug for the treatment of SARS-CoV-2.