Oxygen enhances antiviral innate immunity through maintenance of EGLN1-catalyzed proline hydroxylation of IRF3.

Oxygen is essential for aerobic organisms, but little is known about its role in antiviral immunity. Here, we report that during responses to viral infection, hypoxic conditions repress antiviral-responsive genes independently of HIF signaling. EGLN1 is identified as a key mediator of the oxygen enhancement of antiviral innate immune responses. Under sufficient oxygen conditions, EGLN1 retains its prolyl hydroxylase activity to catalyze the hydroxylation of IRF3 at proline 10. This modification enhances IRF3 phosphorylation, dimerization and nuclear translocation, leading to subsequent IRF3 activation. Furthermore, mice and zebrafish with Egln1 deletion, treatment with the EGLN inhibitor FG4592, or mice carrying an Irf3 P10A mutation are more susceptible to viral infections. These findings not only reveal a direct link between oxygen and antiviral responses, but also provide insight into the mechanisms by which oxygen regulates innate immunity.

Microbiota-gut-brain axis drives overeating disorders.

Overeating disorders (ODs), usually stemming from dieting history and stress, remain a pervasive issue in contemporary society, with the pathological mechanisms largely unresolved. Here, we show that alterations in intestinal microbiota are responsible for the excessive intake of palatable foods in OD mice and patients with bulimia nervosa (BN). Stress combined with a history of dieting causes significant changes in the microbiota and the intestinal metabolism, which disinhibit the vagus nerve terminals in the gut and thereby lead to a subsequent hyperactivation of the gut-brain axis passing through the vagus, the solitary tract nucleus, and the paraventricular nucleus of the thalamus. The transplantation of a probiotic Faecalibacterium prausnitzii or dietary supplement of key metabolites restores the activity of the gut-to-brain pathway and thereby alleviates the OD symptoms. Thus, our study delineates how the microbiota-gut-brain axis mediates energy balance, unveils the underlying pathogenesis of the OD, and provides potential therapeutic strategies.

Identification of histone deacetylase inhibitors as neutrophil recruitment modulators in zebrafish using a chemical library screen.

Tissue injury-induced neutrophil recruitment is a prerequisite for the initiation and amplification of inflammatory responses. Although multiple proteases and enzymes involved in post-translational modification (PTM) of proteins regulate leukocyte recruitment, an unbiased functional screen of enzymes regulating inflammatory leukocyte recruitment has yet to be undertaken. Here, using a zebrafish tail fin amputation (TFA) model to screen a chemical library consisting of 295 compounds that target proteases and PTM enzymes, we identified multiple histone deacetylase (HDAC) inhibitors that modulate inflammatory neutrophil recruitment. AR-42, a pan-HDAC inhibitor, was shown to inhibit neutrophil recruitment in three different zebrafish sterile tissue injury models: a TFA model, a copper-induced neuromast damage and mechanical otic vesicle injury (MOVI) model, and a sterile murine peritonitis model. RNA sequencing analysis of AR-42-treated fish embryos revealed downregulation of neutrophil-associated cytokines/chemokines, and exogenous supplementation with recombinant human IL-1ß and CXCL8 partially restored the defective neutrophil recruitment in AR-42-treated MOVI model fish embryos. We thus demonstrate that AR-42 non-cell-autonomously modulates neutrophil recruitment by suppressing transcriptional expression of cytokines/chemokines, thereby identifying AR-42 as a promising anti-inflammatory drug for treating sterile tissue injury-associated diseases.

Decrease levels of bone morphogenetic protein 6 and noggin in chronic schizophrenia elderly.

Objective: Bone morphogenetic protein 6 (BMP6) and noggin both have been implicated in the pathophysiology of chronic dementia, and chronic schizophrenia (SCZ) has high risk for progressing to dementia in later life. The current study investigated the relationship between blood BMP6/noggin levels and cognitive function in chronic SCZ elderly. Methods: A total of 159 chronic SCZ elderly and 171 community normal controls (NC) were involved in the present study. Blood cytokines including BMP6 and its antagonist-noggin, and cognitive function were measured in all subjects, 157 subjects among them received apolipoprotein E (APOE) genotype test, and 208 subjects received cognitive assessment at 1-year follow-up. Results: Chronic SCZ elderly had decreased levels of blood BMP6 and noggin compared to healthy controls, especially in the subgroup of chronic SCZ with dementia. Blood BMP6 combing with noggin could distinguish chronic SCZ from NC elderly. APOE ε4 carriers had lower levels of BMP6 than APOE non-ε4 carriers under chronic SCZ. Conclusions: There was a significant relationship of blood BMP6/noggin with cognitive performance in chronic SCZ.

Pharmaceutical approaches for COVID-19: An update on current therapeutic opportunities.

SARS-CoV-2, a newly discovered coronavirus, has been linked to the COVID-19 pandemic and is currently an important public health issue. Despite all the work done to date around the world, there is still no viable treatment for COVID-19. This study examined the most recent evidence on the efficacy and safety of several therapeutic options available including natural substances, synthetic drugs and vaccines in the treatment of COVID-19. Various natural compounds such as sarsapogenin, lycorine, biscoclaurine, vitamin B12, glycyrrhizic acid, riboflavin, resveratrol and kaempferol, various vaccines and drugs such as AZD1222, mRNA-1273, BNT162b2, Sputnik V, and remdesivir, lopinavir, favipiravir, darunavir, oseltamivir, and umifenovir, resp., have been discussed comprehensively. We attempted to provide exhaustive information regarding the various prospective therapeutic approaches available in order to assist researchers and physicians in treating COVID-19 patients.

Sfxn5 Regulation of Actin Polymerization for Neutrophil Spreading Depends on a Citrate-Cholesterol-PI(4,5)P2 Pathway.

Cell spreading is an initial and critical step in neutrophil adhesion and migration, leading to neutrophil recruitment to inflammatory tissues. Sideroflexin (Sfxn) family proteins are metabolite transporters located in the mitochondrial membrane. Recombinant SFXN5 protein is a citrate transporter in vitro; however, whether Sfxn5 regulates any cellular behavior or function remains unknown. In this study, we found that small interfering RNA transfection or morpholino injection achieving Sfxn5 deficiency in neutrophils significantly decreased neutrophil recruitment in mice and zebrafish, respectively. Sfxn5 deficiency impaired neutrophil spreading and spreading-associated cellular phenotypes, such as cell adhesion, chemotaxis, and ROS production. Actin polymerization is critical for neutrophil spreading, and we found that actin polymerization in spreading neutrophils was partially inhibited by Sfxn5 deficiency. Mechanistically, we observed that the levels of cytosolic citrate and its downstream metabolic products, acetyl-CoA and cholesterol, were decreased in Sfxn5-deficient neutrophils. The levels of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a mediator for the regulation of actin polymerization by cholesterol, were reduced in the plasma membrane of Sfxn5-deficient neutrophils. Exogenous supplementation with citrate or cholesterol partially reversed the reduction in PI(4,5)P2 levels, defective neutrophil actin polymerization, and cell spreading. Altogether, we demonstrated that Sfxn5 maintains cytosolic citrate levels and ensures the synthesis of sufficient cholesterol to promote actin polymerization in a PI(4,5)P2-dependent manner during neutrophil spreading, which is essential for the eventual inflammatory recruitment of neutrophils. Our study revealed the importance of Sfxn5 in neutrophil spreading and migration, thus identifying, to our knowledge, for the first time, the physiological cellular functions of the Sfxn5 gene.

Zebrafish mavs Is Essential for Antiviral Innate Immunity.

In mammals, the signaling adaptor mitochondrial antiviral signaling protein (MAVS) is a critical determinant in antiviral innate immunity. However, because of the lack of in vivo data, the physiological function of zebrafish mavs in response to viral infection is still not determined. In this study, we demonstrate that the long splicing isoform of zebrafish mavs promotes IFN regulatory factor 3 signaling and NF-κB signaling. Overexpression of this isoform of mavs enhances cellular antiviral responses. Disruption of mavs in zebrafish attenuates survival ratio on challenge with spring viremia of carp virus. Consistently, the antiviral-responsive genes and inflammatory genes are significantly reduced, and the replication of spring viremia of carp virus is increased in mavs-null zebrafish. Therefore, we provide in vivo evidence to support that zebrafish mavs is essential for antiviral innate immunity, similar to mammalian MAVS.

Zebrafish maoc1 Attenuates Spring Viremia of Carp Virus Propagation by Promoting Autophagy-Lysosome-Dependent Degradation of Viral Phosphoprotein.

Spring viremia of carp virus (SVCV) is the causative agent of spring viremia of carp (SVC), an important infectious disease that causes high mortality in aquaculture cyprinids. How the host defends against SVCV infection and the underlying mechanisms are still elusive. In this study, we identify that a novel gene named maoc1 is induced by SVCV infection. maoc1-deficient zebrafish are more susceptible to SVCV infection, with higher virus replication and antiviral gene induction. Further assays indicate that maoc1 interacts with the P protein of SVCV to trigger P protein degradation through the autophagy-lysosomal pathway, leading to the restriction of SVCV propagation. These findings reveal a unique zebrafish defense machinery in response to SVCV infection. IMPORTANCE SVCV P protein plays an essential role in the virus replication and viral immune evasion process. Here, we identify maoc1 as a novel SVCV-inducible gene and demonstrate its antiviral capacity through attenuating SVCV replication, by directly binding to P protein and mediating its degradation via the autophagy-lysosomal pathway. Therefore, this study not only reveals an essential role of maoc1 in fighting against SVCV infection but also demonstrates an unusual host defense mechanism in response to invading viruses.

Evaluating Upstaging in Ductal Carcinoma In Situ Using Preoperative MRI-Based Radiomics.

BACKGROUND: About 20%-40% of patients diagnosed with ductal carcinoma in situ (DCIS) by core needle biopsy (CNB) will develop invasive cancer at the time of excision. Improving the preoperative diagnosis of DCIS is important for surgical planning. PURPOSE: To establish an MRI-based radiomics nomogram for preoperatively evaluating the upstaging of DCIS patients and help with risk stratification. STUDY TYPE: Retrospective. POPULATION: A total of 227 patients (50.5 ± 9.7 years; 67 upstaged DCIS) were divided into training (n = 109), internal (n = 47), and external (n = 71) validation cohort. FIELD STRENGTH/SEQUENCE: 1.5-T or 3-T, dynamic contrast-enhanced (DCE) imaging, and diffusion-weighted imaging (DWI). ASSESSMENT: DCIS lesions were manually segmented using ITK-SNAP software and 1304 radiomic features were extracted from DCE, DWI, and apparent diffusion coef-ficient (ADC) maps, respectively. A radscore was calculated by a random forest algo-rithm based on DCIS upstaging-related radiomic features, which selected by a coarse-to-fine method including interclass correlation coefficient, single-factor anal-ysis, and the least absolute shrinkage and selection operator (LASSO) method. Uni-variate and multivariate logistic regression was used to analyze the independent risk factors, including age, location, lesion size, estrogen receptor (ER) status, and other clinico-pathologic factors. Finally, Mann-Whitney U tests were performed to com-pare the differences in radscore between low/intermediate and high nuclear grade groups for pure DCIS patients. STATISTICAL TESTS: Student's t-tests or Mann-Whitney U tests, chi-square-tests, or Fisher's-tests, univariate and multivariate logistic regression analysis, calibration curve, Youden index, the area under the curve (AUC), Delong test, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses. RESULTS: Eight important radiomic features (two from ADC, three from DWI, and three from DCE) were selected for calculating radscore. Clinical model including age and ER was established with AUCs of 0.747 and 0.738 in the internal and external validation cohorts, respectively. A combined model integrating age, estrogen receptor (ER), and radscore were also constructed with AUCs of 0.887 and 0.881. Further subgroup analysis showed that pure DCIS patients with different nuclear grade have significant differences in radscore. DATA CONCLUSION: Multisequence MRI radiomics may preoperatively evaluate the upstaging of DCIS and might provide personalized image-based clinical decision support. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 2.

Methyltransferase SMYD3 impairs hypoxia tolerance by augmenting hypoxia signaling independent of its enzymatic activity.

Hypoxia-inducible factor (HIF)1α, a main transcriptional regulator of the cellular response to hypoxia, also plays important roles in oxygen homeostasis of aerobic organisms, which is regulated by multiple mechanisms. However, the full cellular response to hypoxia has not been elucidated. In this study, we found that expression of SMYD3, a methyltransferase, augments hypoxia signaling independent of its enzymatic activity. We demonstrated SMYD3 binds to and stabilizes HIF1α via co-immunoprecipitation and Western blot assays, leading to the enhancement of HIF1α transcriptional activity under hypoxia conditions. In addition, the stabilization of HIF1α by SMYD3 is independent of HIF1α hydroxylation by prolyl hydroxylases and the intactness of the von Hippel-Lindau ubiquitin ligase complex. Furthermore, we showed SMYD3 induces reactive oxygen species accumulation and promotes hypoxia-induced cell apoptosis. Consistent with these results, we found smyd3-null zebrafish exhibit higher hypoxia tolerance compared to their wildtype siblings. Together, these findings define a novel role of SMYD3 in affecting hypoxia signaling and demonstrate that SMYD3-mediated HIF1α stabilization augments hypoxia signaling, leading to the impairment of hypoxia tolerance.

A midbrain-reticulotegmental circuit underlies exaggerated startle under fear emotions.

Exaggerated startle has been recognized as a core hyperarousal symptom of multiple fear-related anxiety disorders, such as post-traumatic stress disorder (PTSD) and panic disorder. However, the mechanisms driving this symptom are poorly understood. Here we reveal a neural projection from dorsal raphe nucleus (DRN) to a startle-controlling center reticulotegmental nucleus (RtTg) that mediates enhanced startle response under fear condition. Within RtTg, we identify an inhibitory microcircuit comprising GABAergic neurons in pericentral RtTg (RtTgP) and glutamatergic neurons in central RtTg (RtTgC). Inhibition of this RtTgP-RtTgC microcircuit leads to elevated startle amplitudes. Furthermore, we demonstrate that the conditioned fear-activated DRN 5-HTergic neurons send inhibitory projections to RtTgP GABAergic neurons, which in turn upregulate neuronal activities of RtTgC glutamatergic neurons. Chemogenetic activation of the DRN-RtTgP projections mimics the increased startle response under fear emotions. Moreover, conditional deletion of 5-HT1B receptor from RtTgP GABAergic neurons largely reverses the exaggeration of startle during conditioned fear. Thus, our study establishes the disinhibitory DRN-RtTgP-RtTgC circuit as a critical mechanism underlying exaggerated startle under fear emotions, and provides 5-HT1B receptor as a potential therapeutic target for treating hyperarousal symptom in fear-associated psychiatric disorders.

Zebrafish sirt5 Negatively Regulates Antiviral Innate Immunity by Attenuating Phosphorylation and Ubiquitination of mavs.

The signaling adaptor MAVS is a critical determinant in retinoic acid-inducible gene 1-like receptor signaling, and its activation is tightly controlled by multiple mechanisms in response to viral infection, including phosphorylation and ubiquitination. In this article, we demonstrate that zebrafish sirt5, one of the sirtuin family proteins, negatively regulates mavs-mediated antiviral innate immunity. Sirt5 is induced by spring viremia of carp virus (SVCV) infection and binds to mavs, resulting in attenuating phosphorylation and ubiquitination of mavs. Disruption of sirt5 in zebrafish promotes survival ratio after challenge with SVCV. Consistently, the antiviral responsive genes are enhanced, and the replication of SVCV is diminished in sirt5-dificient zebrafish. Therefore, we reveal a function of zebrafish sirt5 in the negative regulation of antiviral innate immunity by targeting mavs.

Treatment efficacy of Lianhua Qingwen capsules for eraly-stage COVID-19.

OBJECTIVE: To systematically determine the effect of Lianhua Qingwen Capsules on the early antiviral and anti-inflammatory action against COVID-19 (Coronavirus 2019) and its applicational value in the treatment of COVID-19. METHODS: The clinical data of 66 early-mid-stage COVID-19 patients admitted to hospitals in Guangzhou between January 2020 and April 2020 were retrospectively analyzed. The patients receiving Lianhua Qingwen Capsule treatment were assigned to the observation group (n=33) and those given conventional therapy were included in the control group (n=33). The two groups were compared in terms of clinical effects and main symptom (fever, cough and fatigue) disappearance rate. RESULTS: In comparison with the control group, 1) the total effective rate was significantly higher in the observation group (P<0.05); 2) the disappearance rates of fever, cough and fatigue were statistically higher in the observation group; 3) the treatment time was significantly shorter and patient recovery was significantly better in the observation group; 4) the laboratory index levels [white blood cell (WBC), interleukin-6 (IL-6), serum amyloid A (SAA)] were better in the observation group. CONCLUSION: Lianhua Qingwen Capsules can significantly improve the total effective rate for COVID-19 patients, as well as shorten the hospital stay and treatment time, which is worth of promotion in the clinic.

A Brainstem reticulotegmental neural ensemble drives acoustic startle reflexes.

The reticulotegmental nucleus (RtTg) has long been recognized as a crucial component of brainstem reticular formation (RF). However, the function of RtTg and its related circuits remain elusive. Here, we report a role of the RtTg in startle reflex, a highly conserved innate defensive behaviour. Optogenetic activation of RtTg neurons evokes robust startle responses in mice. The glutamatergic neurons in the RtTg are significantly activated during acoustic startle reflexes (ASR). Chemogenetic inhibition of the RtTg glutamatergic neurons decreases the ASR amplitudes. Viral tracing reveals an ASR neural circuit that the cochlear nucleus carrying auditory information sends direct excitatory innervations to the RtTg glutamatergic neurons, which in turn project to spinal motor neurons. Together, our findings describe a functional role of RtTg and its related neural circuit in startle reflexes, and demonstrate how the RF connects auditory system with motor functions.

Arginine monomethylation by PRMT7 controls MAVS-mediated antiviral innate immunity.

Accurate control of innate immune responses is required to eliminate invading pathogens and simultaneously avoid autoinflammation and autoimmune diseases. Here, we demonstrate that arginine monomethylation precisely regulates the mitochondrial antiviral-signaling protein (MAVS)-mediated antiviral response. Protein arginine methyltransferase 7 (PRMT7) forms aggregates to catalyze MAVS monomethylation at arginine residue 52 (R52), attenuating its binding to TRIM31 and RIG-I, which leads to the suppression of MAVS aggregation and subsequent activation. Upon virus infection, aggregated PRMT7 is disabled in a timely manner due to automethylation at arginine residue 32 (R32), and SMURF1 is recruited to PRMT7 by MAVS to induce proteasomal degradation of PRMT7, resulting in the relief of PRMT7 suppression of MAVS activation. Therefore, we not only reveal that arginine monomethylation by PRMT7 negatively regulates MAVS-mediated antiviral signaling in vitro and in vivo but also uncover a mechanism by which PRMT7 is tightly controlled to ensure the timely activation of antiviral defense.

Gut microbiota mediates the effects of curcumin on enhancing Ucp1-dependent thermogenesis and improving high-fat diet-induced obesity.

Due to extremely poor systemic bioavailability, the mechanism by which curcumin increases energy expenditure remains unelucidated. Accumulating evidence suggests a strong association between the gut microbiota (GM) and energy metabolism. We investigated whether the GM mediates the effects of curcumin on improving energy homeostasis. High-fat diet (HFD)-fed wild type, uncoupling protein 1 (Ucp1) knockout and G protein-coupled membrane receptor 5 (TGR5) knockout mice were treated with curcumin (100 mg kg-1 d-1, p.o.). Curcumin-treated HFD-fed mice displayed decreased body weight gain and augmented cold tolerance due to enhanced adaptive thermogenesis as compared with that in control mice. The anti-obesity effects of curcumin were abolished by Ucp1 knockout. 16S ribosomal DNA sequencing analysis revealed that curcumin restructured the GM in HFD-fed mice. Fecal microbiota transplantation (FMT) and endogenous GM depletion indicated that the GM mediated the enhanced effect of curcumin on Ucp1-dependent thermogenesis. Curcumin altered bile acid (BA) metabolism with increased fractions of circulating deoxycholic acid (DCA) and lithocholic acid (LCA), which are the two most potent ligands for TGR5. Consistently, the enhanced effect of curcumin on Ucp1-dependent thermogenesis was eliminated by TGR5 knockout. Curcumin requires the GM and TGR5 to activate the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway in thermogenic adipose tissue. Here, we demonstrated that the GM mediates the effects of curcumin on enhancing Ucp1-dependent thermogenesis and ameliorating HFD-induced obesity by influencing BA metabolism. We disclosed the potential of nutritional and pharmacologic manipulations of the GM to enhance Ucp1-dependent thermogenesis in the prevention and treatment of obesity.

TET is targeted for proteasomal degradation by the PHD-pVHL pathway to reduce DNA hydroxymethylation.

Hypoxia-inducible factors are heterodimeric transcription factors that play a crucial role in a cell's ability to adapt to low oxygen. The von Hippel-Lindau tumor suppressor (pVHL) acts as a master regulator of HIF activity, and its targeting of prolyl hydroxylated HIF-α for proteasomal degradation under normoxia is thought to be a major mechanism for pVHL tumor suppression and cellular response to oxygen. Whether pVHL regulates other targets through a similar mechanism is largely unknown. Here, we identify TET2/3 as novel targets of pVHL. pVHL induces proteasomal degradation of TET2/3, resulting in reduced global 5-hydroxymethylcytosine levels. Conserved proline residues within the LAP/LAP-like motifs of these two proteins are hydroxylated by the prolyl hydroxylase enzymes (PHD2/EGLN1 and PHD3/EGLN3), which is prerequisite for pVHL-mediated degradation. Using zebrafish as a model, we determined that global 5-hydroxymethylcytosine levels are enhanced in vhl-null, egln1a/b-double-null, and egln3-null embryos. Therefore, we reveal a novel function for the PHD-pVHL pathway in regulating TET protein stability and activity. These data extend our understanding of how TET proteins are regulated and provide new insight into the mechanisms of pVHL in tumor suppression.

Zebrafish F-box Protein fbxo3 Negatively Regulates Antiviral Response through Promoting K27-Linked Polyubiquitination of the Transcription Factors irf3 and irf7.

FBXO3, belongs to the F-box family of proteins, which has been reported to involve in host autoimmune and inflammatory responses by promoting its substrates for ubiquitylation. However, thus far, its physiological function in antiviral immunity remains elusive. In this study, we report that overexpression of zebrafish fbxo3 suppresses cellular antiviral responses. Moreover, disruption of fbxo3 in zebrafish increases the survival rate upon spring viremia of carp virus exposure. Further assays indicate that fbxo3 interacts with irf3/irf7 and specifically catalyzes K27-linked ubiquitination of irf3 and irf7, resulting in proteasomal degradation of irf3 and irf7. However, the F-box domain of fbxo3 is not required for fbxo3 to interact with irf3/irf7 and to inhibit transactivity of irf3 and irf7. This study provides novel insights into fbxo3 function and the underlying mechanisms. In addition, it sheds new light on the regulation of IFN-I signaling by F-box proteins.