A viral effector blocks the turnover of a plant NLR receptor to trigger a robust immune response.

Plant intracellular nucleotide-binding and leucine-rich repeat immune receptors (NLRs) play a key role in activating a strong pathogen defense response. Plant NLR proteins are tightly regulated and accumulate at very low levels in the absence of pathogen effectors. However, little is known about how this low level of NLR proteins is able to induce robust immune responses upon recognition of pathogen effectors. Here, we report that, in the absence of effector, the inactive form of the tomato NLR Sw-5b is targeted for ubiquitination by the E3 ligase SBP1. Interaction of SBP1 with Sw-5b via only its N-terminal domain leads to slow turnover. In contrast, in its auto-active state, Sw-5b is rapidly turned over as SBP1 is upregulated and interacts with both its N-terminal and NB-LRR domains. During infection with the tomato spotted wilt virus, the viral effector NSm interacts with Sw-5b and disrupts the interaction of Sw-5b with SBP1, thereby stabilizing the active Sw-5b and allowing it to induce a robust immune response.

NLRs derepress MED10b- and MED7-mediated repression of jasmonate-dependent transcription to activate immunity.

Plant intracellular nucleotide-binding domain, leucine-rich repeat-containing receptors (NLRs) activate a robust immune response upon detection of pathogen effectors. How NLRs induce downstream immune defense genes remains poorly understood. The Mediator complex plays a central role in transducing signals from gene-specific transcription factors to the transcription machinery for gene transcription/activation. In this study, we demonstrate that MED10b and MED7 of the Mediator complex mediate jasmonate-dependent transcription repression, and coiled-coil NLRs (CNLs) in Solanaceae modulate MED10b/MED7 to activate immunity. Using the tomato CNL Sw-5b, which confers resistance to tospovirus, as a model, we found that the CC domain of Sw-5b directly interacts with MED10b. Knockout/down of MED10b and other subunits including MED7 of the middle module of Mediator activates plant defense against tospovirus. MED10b was found to directly interact with MED7, and MED7 directly interacts with JAZ proteins, which function as transcriptional repressors of jasmonic acid (JA) signaling. MED10b-MED7-JAZ together can strongly repress the expression of JA-responsive genes. The activated Sw-5b CC interferes with the interaction between MED10b and MED7, leading to the activation of JA-dependent defense signaling against tospovirus. Furthermore, we found that CC domains of various other CNLs including helper NLR NRCs from Solanaceae modulate MED10b/MED7 to activate defense against different pathogens. Together, our findings reveal that MED10b/MED7 serve as a previously unknown repressor of jasmonate-dependent transcription repression and are modulated by diverse CNLs in Solanaceae to activate the JA-specific defense pathways.

Interspecies/Intergroup Complementation of Orthotospovirus Replication and Movement through Reverse Genetics Systems.

Orthotospoviruses, the plant-infecting bunyaviruses, cause serious diseases in agronomic crops and pose major threats to global food security. The family of Tospoviridae contains more than 30 members that are classified into two geographic groups, American-type and Euro/Asian-type orthotospovirus. However, the genetic interaction between different species and the possibility, during mixed infections, for transcomplementation of gene functions by orthotospoviruses from different geographic groups remains underexplored. In this study, minireplicon-based reverse genetics (RG) systems have been established for Impatiens necrotic spot virus (INSV) (an American-type orthotospovirus) and for Calla lily chlorotic spot virus and Tomato zonate spot virus (CCSV and TZSV) (two representative Euro/Asian orthotospoviruses). Together with the earlier established RG system for Tomato spotted wilt virus (TSWV), a type species of the Orthotospovirus American-clade, viral replicase/movement proteins were exchanged and analyzed on interspecies transcomplementation. Whereas the homologous RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) protein supported the replication of orthotospoviruses from both geographic groups, heterologous combinations of RdRp from one group and N from the other group were unable to support the replication of viruses from both groups. Furthermore, the NSm movement protein (MP), from both geographic groups of orthotospoviruses, was able to transcomplement heterologous orthotospoviruses or a positive-strand Cucumber mosaic virus (CMV) in their movement, albeit with varying efficiency. MP from Rice stripe tenuivirus (RSV), a plant-infecting bunyavirus that is distinct from orthotospoviruses, or MP from CMV also moves orthotospoviruses. Our findings gain insights into the genetic interaction/reassortant potentials for the segmented plant orthotospoviruses. IMPORTANCE Orthotospoviruses are agriculturally important negative-strand RNA viruses and cause severe yield-losses on many crops worldwide. Whereas the emergence of new animal-infecting bunyaviruses is frequently associated with genetic reassortants, this issue remains underexposed with the plant-infecting orthotospovirus. With the development of reverse genetics systems for orthotospoviruses from different geographic regions, the interspecies/intergroup replication/movement complementation between American- and Euro/Asian-type orthotospoviruses were investigated. Genomic RNAs from American orthotospoviruses can be replicated by the RdRp and N from those of Euro/Asia-group orthotospoviruses, and vice versa. However, their genomic RNAs cannot be replicated by a heterologous combination of RdRp from one geographic group and N from another geographic group. Cell-to-cell movement of viral entity is supported by NSm from both geographic groups, with highest efficiency by NSm from viruses belonging to the same group. Our findings provide important insights into the genetic interaction and exchange ability of viral gene functions between different species of orthotospovirus.

Polysaccharides from Dendrobium officinale improve obesity-induced insulin resistance through the gut microbiota and the SOCS3-mediated insulin receptor substrate-1 signaling pathway.

BACKGROUND: Obesity induces insulin resistance and chronic inflammation, impacting human health. The relationship between obesity, gut microbiota, and regulatory mechanisms has been studied extensively. Dendrobium officinale polysaccharide (DOP), a traditional Chinese herbal medicine, potentially reduces insulin resistance. However, the mechanism through which DOP affects gut microbiota and alleviates obesity-induced insulin resistance in rats requires further investigation. RESULTS: The current study aimed to assess the impact of DOP on gut microbiota and insulin resistance in rats on a high-fat diet. The results revealed that DOP effectively reduced blood lipids, glucose disorders, oxidative stress, and inflammatory infiltration in the liver of obese Sprague Dawley rats. This was achieved by downregulating SOCS3 expression and upregulating insulin receptor substrate-1 (IRS-1) by regulating the JAK/STAT/SOCS3 signaling pathway. Notably, DOP intervention enhanced the abundance of beneficial gut microbiota and reduced harmful microbiota. Correlation analysis demonstrated significant associations among intestinal microbiota, SOCS3-mediated IRS-1 expression, and inflammatory factors. CONCLUSION: Dendrobium officinale polysaccharide regulated the gut microbiota, enhanced IRS-1 expression, and mitigated liver injury and insulin resistance due to a high-fat diet. These findings depict the potential anti-insulin resistance properties of DOP and offer further evidence for addressing obesity and its complications. © 2023 Society of Chemical Industry.

Small-Diameter Transjugular Intrahepatic Portosystemic Shunt versus Endoscopic Variceal Ligation Plus Propranolol for Variceal Rebleeding in Advanced Cirrhosis.

Background Some studies have shown that transjugular intrahepatic portosystemic shunt (TIPS) placement within 72 hours of admission improves survival in patients at high risk who present with acute variceal bleeding. However, the role of small-diameter covered TIPS in the secondary prophylaxis of variceal bleeding is still debatable. Purpose To compare the efficacy of 8-mm TIPS and endoscopic variceal ligation (EVL) plus propranolol in the prevention of variceal rebleeding among participants with advanced cirrhosis. Materials and Methods Between June 2015 and December 2018, participants admitted to the hospital for variceal bleeding were considered for enrollment in this randomized controlled trial (ClinicalTrials.gov). Participants with Child-Pugh class B or C cirrhosis were randomly assigned to receive an 8-mm covered TIPS or EVL and propranolol. The primary end point was recurrent variceal bleeding assessed using Kaplan-Meier curve analysis. Secondary end points included survival and overt hepatic encephalopathy (HE) assessed using Kaplan-Meier curve analysis. Results A total of 100 participants were enrolled, with 50 randomly assigned to the EVL plus propranolol group (median age, 54 years; IQR, 45-60 years; 29 male, 21 female) and 50 randomly assigned to the TIPS group (median age, 49 years; IQR, 43-56 years; 32 male, 18 female). The median follow-up period was 43.4 months. In the TIPS group, variceal rebleeding risk was reduced compared with variceal rebleeding risk in the EVL plus propranolol group (hazard ratio [HR], 0.31; 95% CI: 0.14, 0.69; P = .008), but the incidence of overt HE was higher in the TIPS group (30.0% vs 16.0%, P = .03). No differences in survival were observed between the two groups (1-year survival: TIPS, 98.0%; EVL plus propranolol, 92.0%; 3-year survival: TIPS, 94.0%; EVL plus propranolol, 85.7%; HR, 0.52; 95% CI: 0.19, 1.42; P = .22). Conclusion When compared with EVL plus propranolol, 8-mm TIPS led to reduced variceal rebleeding but did not impact overall survival in participants with Child-Pugh class B or C cirrhosis. Clinical trial registration no. NCT02477384 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Barth in this issue.

MELD 3.0 Score for Predicting Survival in Patients with Cirrhosis After Transjugular Intrahepatic Portosystemic Shunt Creation.

BACKGROUND AND AIMS: The selection of appropriate candidates for transjugular intrahepatic portosystemic shunt (TIPS) is important and challenging. To validate the Model for End-Stage Liver Disease (MELD) 3.0 in predicting mortality in patients with cirrhosis after TIPS creation. METHODS: A total of 855 consecutive patients with cirrhosis from December 2011 to October 2019 who underwent TIPS placement were retrospectively reviewed. The prognostic value of the MELD 3.0, MELD, MELD-Na, Child-Pugh and FIPS score was assessed using Harrell's C concordance index (c-index). The Hosmer-Lemeshow test was used to test the goodness of fit of all models and the calibration plot was drawn. RESULTS: The c-index of the MELD 3.0 in predicting 3-month mortality was 0.727 (0.645-0.808), which were significantly superior to the MELD (0.663 [0.565-0.761]; P = 0.015), MELD-Na (0.672 [0.577-0.768]; P = 0.008) and FIPS (0.582 [0.477-0.687]; P = 0.015). The Child-Pugh score reached c-indices of 0.754 (0.673-0.835), 0.720 (0.649-0.792), 0.705 (0.643-0.766) and 0.665 (0.614-0.716) for 3-month, 6-month, 1-year, and 2-year mortality, respectively, which seems comparable to MELD 3.0. A MELD 3.0 of 14 could be used as a cut-off point for discriminating between high- and low-risk patients. The MELD 3.0 could stratify patients with Child-Pugh grade B (log-rank P < 0.001). The Child-Pugh score could stratify patients defined as low risk by MELD 3.0 (log-rank P < 0.001). CONCLUSIONS: The MELD 3.0 was significantly superior to the MELD, MELD-Na and FIPS scores in predicting mortality in patients with cirrhosis after TIPS creation.

Endoscopic Cyanoacrylate Injection Versus Balloon-Occluded Retrograde Transvenous Obliteration for Prevention of Gastric Variceal Bleeding: A Randomized Controlled Trial.

BACKGROUND AND AIMS: The optimal treatment for gastric varices (GVs) is a topic that remains open for study. This study compared the efficacy and safety of endoscopic cyanoacrylate injection and balloon-occluded retrograde transvenous obliteration (BRTO) to prevent rebleeding in patients with cirrhosis and GVs after primary hemostasis. APPROACH AND RESULTS: Patients with cirrhosis and history of bleeding from gastroesophageal varices type 2 or isolated gastric varices type 1 were randomized to cyanoacrylate injection (n = 32) or BRTO treatment (n = 32). Primary outcomes were gastric variceal rebleeding or all-cause rebleeding. Patient characteristics were well balanced between two groups. Mean follow-up time was 27.1 ± 12.0 months in a cyanoacrylate injection group and 27.6 ± 14.3 months in a BRTO group. Probability of gastric variceal rebleeding was higher in the cyanoacrylate injection group than in the BRTO group (P = 0.024). Probability of remaining free of all-cause rebleeding at 1 and 2 years for cyanoacrylate injection versus BRTO was 77% versus 96.3% and 65.2% versus 92.6% (P = 0.004). Survival rates, frequency of complications, and worsening of esophageal varices were similar in both groups. BRTO resulted in fewer hospitalizations, inpatient stays, and lower medical costs. CONCLUSIONS: BRTO is more effective than cyanoacrylate injection in preventing rebleeding from GVs, with similar frequencies of complications and mortalities.

Liver stiffness by two-dimensional shear wave elastography for screening high-risk varices in patients with compensated advanced chronic liver disease.

OBJECTIVES: To investigate the usefulness of the criteria with liver stiffness (LS) measured by two-dimensional shear wave elastography (2D-SWE) and platelet count (PLT) for ruling out high-risk varices in patients with compensated advanced chronic liver disease (cACLD). METHODS: A total of 661 patients with cACLD had successfully undergone 2D-SWE and endoscopy screening. We analyzed risk factors for the presence of high-risk varices and compared proportions of patients who were spared endoscopy when used the predicting criteria with LS (ranged from 16 to 25 kPa) and PLT (ranged from 80 × 109/L to 150 × 109/L). RESULTS: PLT, albumin, LS were found to be independent predictors of high-risk varices. The LS values for ruling out and ruling in high-risk varices were 14.0 kPa and 24.8 kPa, respectively. When the Baveno VI criteria LS < 20 kPa and PLT > 150 × 109/L were used, the high-risk varices miss rate was 2.1%, while the saved endoscopy rate only was 19.2%. The new criteria that LS < 16 kPa and PLT > 100 × 109/L saved 30.4-34.6% endoscopy with 0-3.2% high-risk varices miss rate in the subgroup analysis stratified according to the types of underlying liver disease. CONCLUSIONS: The Baveno VI criteria can be applied to LS measurement by 2D-SWE. The new criteria that LS < 16 kPa and PLT > 100 × 109/L could be a potential model to spare more endoscopy screening with < 5% high-risk varices miss rate. KEY POINTS: • LS measured by 2D-SWE is reliable predictive factor for predicting all-size varices and high-risk varices in patients with compensated advanced chronic liver disease. • LS measured by 2D-SWE < 16 kPa and PLT > 100 × 109 /L, which can spare more endoscopy than Baveno VI criteria with < 5% high-risk varices miss rate. • The Baveno VI criteria can be applied to LS measurement by 2D-SWE.

Inference and uncertainty quantification for noisy matrix completion.

Noisy matrix completion aims at estimating a low-rank matrix given only partial and corrupted entries. Despite remarkable progress in designing efficient estimation algorithms, it remains largely unclear how to assess the uncertainty of the obtained estimates and how to perform efficient statistical inference on the unknown matrix (e.g., constructing a valid and short confidence interval for an unseen entry). This paper takes a substantial step toward addressing such tasks. We develop a simple procedure to compensate for the bias of the widely used convex and nonconvex estimators. The resulting debiased estimators admit nearly precise nonasymptotic distributional characterizations, which in turn enable optimal construction of confidence intervals/regions for, say, the missing entries and the low-rank factors. Our inferential procedures do not require sample splitting, thus avoiding unnecessary loss of data efficiency. As a byproduct, we obtain a sharp characterization of the estimation accuracy of our debiased estimators in both rate and constant. Our debiased estimators are tractable algorithms that provably achieve full statistical efficiency.

[Efficacy Analysis of Transcatheter Arterial Embolization in Acute Non-Variceal Upper Gastrointestinal Bleeding].

Objective: To evaluate the safety and effectiveness of transcatheter arterial embolization (TAE) in the treatment of acute non-variceal upper gastrointestinal bleeding (ANVUGIB), and to guide clinical practice and continue to optimize diagnosis and treatment strategies. Methods: This retrospective study included 266 patients who underwent angiography due to ANVUGIB between March 2016 and March 2021. Data on the positive rate of angiography, the technical success rate and clinical success rate of TAE, and the rebleeding rate and the all-cause mortality within 30 days after TAE treatment were collected, and the influencing factors relevant to the above events were analyzed accordingly. Results: All 266 patients completed angiography--the positive rate of angiography was 54.1% (144/266), the total technical success rate was 97.3% (217/223), the clinical success rate was 73.1% (155/212), and the rebleeding rate and all-cause mortality within 30 days were 26.9% (57/212) and 16.1% (35/217), respectively. This study found that shock index>1 ( OR=5.950; 95% CI: 1.481-23.895; P=0.012), computed tomography angiography (CTA) positive result ( OR=6.813; 95% CI: 1.643-28.252; P=0.008) and interval<24 h ( OR=10.530; 95% CI: 2.845-38.976; P<0.001) were independent predictors of positive angiography. Shock index>1 ( OR=2.544; 95% CI: 1.301-4.972; P=0.006) and INR>1.5 ( OR=3.207; 95% CI: 1.381-7.451; P=0.007) were independent risk factors for rebleeding. Patients with postoperative bleeding ( OR=3.174; 95% CI: 1.164-8.654; P=0.024) and patients with rebleeding after embolization ( OR=34.665; 95% CI: 11.471-104.758; P<0.001) had a higher risk of death within 30 days. Conclusion: TAE is safe and effective in the treatment of ANVUGIB. Patients with shock index>1 and positive CTA are more likely to be angiographic positive, and should undergo angiography as early as possible after bleeding. In addition, rebleeding after embolization deserves high attention.