Hydrogen Sulfide Promotes Platelet Autophagy via PDGFR-α/PI3K/Akt Signaling in Cirrhotic Thrombocytopenia.

Background and Aims: The role of platelet autophagy in cirrhotic thrombocytopenia (CTP) remains unclear. This study aimed to investigate the impact of platelet autophagy in CTP and elucidate the regulatory mechanism of hydrogen sulfide (H2S) on platelet autophagy. Methods: Platelets from 56 cirrhotic patients and 56 healthy individuals were isolated for in vitro analyses. Autophagy markers (ATG7, BECN1, LC3, and SQSTM1) were quantified using enzyme-linked immunosorbent assay, while autophagosomes were visualized through electron microscopy. Western blotting was used to assess the autophagy-related proteins and the PDGFR/PI3K/Akt/mTOR pathway following treatment with NaHS (an H2S donor), hydroxocobalamin (an H2S scavenger), or AG 1295 (a selective PDGFR-α inhibitor). A carbon tetrachloride-induced cirrhotic BALB/c mouse model was established. Cirrhotic mice with thrombocytopenia were randomly treated with normal saline, NaHS, or hydroxocobalamin for 15 days. Changes in platelet count and aggregation rate were observed every three days. Results: Cirrhotic patients with thrombocytopenia exhibited significantly decreased platelet autophagy markers and endogenous H2S levels, alongside increased platelet aggregation, compared to healthy controls. In vitro, NaHS treatment of platelets from severe CTP patients elevated LC3-II levels, reduced SQSTM1 levels, and decreased platelet aggregation in a dose-dependent manner. H2S treatment inhibited PDGFR, PI3K, Akt, and mTOR phosphorylation. In vivo, NaHS significantly increased LC3-II and decreased SQSTM1 expressions in platelets of cirrhotic mice, reducing platelet aggregation without affecting the platelet count. Conclusions: Diminished platelet autophagy potentially contributes to thrombocytopenia in cirrhotic patients. H2S modulates platelet autophagy and functions possibly via the PDGFR-α/PI3K/Akt/mTOR signaling pathway.

Computed Tomography Images of Spontaneous Portosystemic Shunt in Liver Cirrhosis.

Spontaneous portosystemic shunt (SPSS) refers to collateral vessels that communicate between the portal vein system and systemic circulation. SPSS mainly includes esophageal varices, gastric varices, left gastric vein, recanalized paraumbilical vein, abdominal wall varices, and spontaneous splenorenal shunt. SPSS contributes to the development of hepatic encephalopathy caused by portal vein inflow bypassing and carries a higher risk of death in liver cirrhosis. Abdominal contrast-enhanced computed tomography is a major imaging approach to establish a diagnosis of SPSS and evaluate its location and feature. This review primarily describes the main contrast-enhanced CT features of SPSS in liver cirrhosis.

Review article: thromboelastography in liver diseases.

BACKGROUND: Patients with liver diseases have complicated haemostatic alternations, resulting in both bleeding and thromboembolic complications, which cannot be sufficiently evaluated by conventional coagulation tests (CCTs), such as platelet count or prothrombin time. Thromboelastography (TEG) is a whole blood viscoelastic test which globally reflects changes in the haemostatic system, and its utility in evaluating patients with liver disease is increasingly recognised. AIMS: To review the current evidence and clinical significance of TEG in liver diseases. METHODS: Literature regarding TEG and liver diseases was comprehensively searched. RESULTS: TEG is associated closely with the severity and aetiology of liver disease, the course of infection and the risk of bleeding and death, but not the risk of portal venous system thrombosis. Additionally, TEG-guided transfusion protocols can significantly decrease the requirement for blood products compared to those guided by CCTs. CONCLUSION: TEG can reflect the haemostatic status of liver diseases more comprehensively than CCTs. It has the potential to assess the severity of liver diseases, predict the risk of bleeding and death in patients with liver disease and guide blood product transfusion. Future studies should standardise the use of TEG for assessing disease severity and development of clinical events and guiding blood product transfusion in patients with liver diseases.

Association of thromboelastography profile with severity of liver cirrhosis and portal venous system thrombosis.

BACKGROUND AND AIM: Hemostasis profile is often complicated in liver cirrhosis. Thromboelastography is a global viscoelastic test recommended by the current practice guideline and consensus. This cross-sectional study aimed to evaluate the association of thromboelastography profile with severity of liver cirrhosis and presence of portal venous system thrombosis (PVST). METHODS: Overall, 116 and 50 cirrhotic patients were included in the Shenyang and Xi'an cohorts, respectively. Thromboelastography parameters were compared between cirrhotic patients with Child-Pugh class A and B/C, those with and without decompensated events, and those with and without PVST. Hypercoagulability would be considered if at least two of the following thromboelastography parameters were met: shortened reactive time (R), shortened coagulation time (K), increased angle, and increased maximum amplitude (MA). RESULTS: In the Shenyang cohort, 16 patients had shortened R, of whom seven (43.75%) had prolonged K and 11 (68.75%) decreased MA. In the Xi'an cohort, 24 patients had shortened R, of whom seven (29.17%) had prolonged K and 15 (62.50%) decreased MA. In the Shenyang cohort, the prevalence of hypercoagulability was not significantly different between cirrhotic patients with Child-Pugh class A and B/C (3.85% vs. 6.25%, P = 0.873), those with and without decompensated events (5.49% vs. 4.00%, P = 1.000), and those with and without PVST (4.17% vs. 5.88%, P = 1.000), which were similar to the results obtained in the Xi'an cohort. CONCLUSION: There is a high rate of discordance between R and other thromboelastography parameters. In addition, hypercoagulability may not be related to more advanced stage of liver cirrhosis or presence of PVST.

Natural history and predictors associated with the evolution of portal venous system thrombosis in liver cirrhosis.

BACKGROUND: Portal venous system thrombosis (PVST) will progress in some cases, indicating worse outcome and the necessity of antithrombotic treatment, but will spontaneously improve in others. It is crucial to understand the natural history of PVST in liver cirrhosis. However, the knowledge regarding how to predict the evolution of PVST in cirrhotic patients is very scant. METHODS: Sixty-nine cirrhotic patients without malignancy, who had undergone repeated contrast-enhanced computed tomography or MRI to evaluate the severity of PVST at the first and last admissions, were included. Logistic regression analysis was performed to identify the risk factors for the evolution of PVST in liver cirrhosis. Odds ratios (ORs) were calculated. RESULTS: Among 42 patients without PVST at the first admission, 10 (23.8%) developed PVST at the last admission. Serum albumin level (OR = 0.873), prothrombin time (OR = 1.619), activated partial thromboplastin time (OR = 1.169), Child-Pugh score (OR = 1.560) and model for end-stage liver disease (MELD) score (OR = 1.292) at the last admission were significant risk factors associated with the development of PVST. Among 27 patients with PVST at the first admission, 11 (40.7%), 4 (14.8%) and 12 (44.4%) had improvement, stabilization and progression of PVST at the last admission, respectively. ΔMELD score (OR = 0.714) was the only significant risk factor associated with the improvement of PVST; additionally, serum albumin level at the first admission (OR = 1.236) was the only significant risk factor associated with the progression of PVST. CONCLUSION: Aggravation and amelioration of liver dysfunction may predict the development and improvement of PVST in liver cirrhosis, respectively.

Auxilin-like protein MoSwa2 promotes effector secretion and virulence as a clathrin uncoating factor in the rice blast fungus Magnaporthe oryzae.

Plant pathogens exploit the extracellular matrix (ECM) to inhibit host immunity during their interactions with the host. The formation of ECM involves a series of continuous steps of vesicular transport events. To understand how such vesicle trafficking impacts ECM and virulence in the rice blast fungus Magnaporthe oryzae, we characterised MoSwa2, a previously identified actin-regulating kinase MoArk1 interacting protein, as an orthologue of the auxilin-like clathrin uncoating factor Swa2 of the budding yeast Saccharomyces cerevisiae. We found that MoSwa2 functions as an uncoating factor of the coat protein complex II (COPII) via an interaction with the COPII subunit MoSec24-2. Loss of MoSwa2 led to a deficiency in the secretion of extracellular proteins, resulting in both restricted growth of invasive hyphae and reduced inhibition of host immunity. Additionally, extracellular fluid (ECF) proteome analysis revealed that MoSwa2-regulated extracellular proteins include many redox proteins such as the berberine bridge enzyme-like (BBE-like) protein MoSef1. We further found that MoSef1 functions as an apoplastic virulent factor that inhibits the host immune response. Our studies revealed a novel function of a COPII uncoating factor in vesicular transport that is critical in the suppression of host immunity and pathogenicity of M. oryzae.

Nonselective ß-Blockers May Progress the Thrombosis of Portal Venous System in Cirrhotic Patients: A Retrospective Observational Study.

INTRODUCTION: Occlusive portal venous system thrombosis (PVT) is significantly associated with poor outcomes in cirrhotic patients. Nonselective ß-blockers (NSBBs) may be associated with the development of PVT. However, the role of NSBBs in progressing thrombosis remains unclear. METHODS: Forty-three patients on whom contrast-enhanced computed tomography or magnetic resonance imaging was performed twice, and for whom there was detailed information regarding NSBBs, were eligible in this study, including 16 in the NSBBs group and 27 in the no NSBBs group. A composite endpoint of progressing thrombosis included the development of PVT in patients without PVT and aggravation of PVT in patients with PVT. Logistic regression analysis was employed to identify the effect of NSBBs on the progression of PVT. RESULTS: At the last admission, 13 patients had progressing thrombosis. The incidence of progressing thrombosis was significantly higher in the NSBBs group than in the no NSBBs group [50.0% (8/16) vs. 18.5% (5/27), P = 0.030]. The use of NSBBs (odds ratio 4.400, 95% confidence interval 1.107-17.482, P = 0.035) was significantly associated with progressing thrombosis in univariate logistic regression analyses, but not significant (odds ratio 4.084, 95% confidence interval 0.488-34.158, P = 0.194) in multivariate logistic regression analyses. CONCLUSIONS: NSBBs may play a role in the progression of PVT in liver cirrhosis. The benefits and risks of NSBBs in the management of liver cirrhosis should be fully weighed.

MicroRNA-like milR236, regulated by transcription factor MoMsn2, targets histone acetyltransferase MoHat1 to play a role in appressorium formation and virulence of the rice blast fungus Magnaporthe oryzae.

MicroRNAs (miRNAs) play important roles in various cellular growth and developmental processes through post-transcriptional gene regulation via mRNA cleavage and degradation and the inhibition of protein translation. To explore if miRNAs play a role in appressoria formation and virulence that are also governed by the regulators of G-protein signaling (RGS) proteins in the rice blast fungus Magnaporthe oryzae, we have compared small RNA (sRNA) production between several ΔMorgs mutant and the wild-type strains. We have identified sRNA236 as a microRNA-like milR236 that targets the encoding sequence of MoHat1, a histone acetyltransferase type B catalytic subunit involved in appressorium function and virulence. We have also found that milR236 overexpression induces delayed appressorium formation and virulence attenuation, similar to those displayed by the ΔMohat1 mutant strain. Moreover, we have shown that the transcription factor MoMsn2 binds to the promoter sequence of milR236 to further suppress MoHAT1 transcription and MoHat1-regulated appressorium formation and virulence. In summary, by identifying a novel regulatory role of sRNA in the blast fungus, our studies reveal a new paradigm in the multifaceted regulatory pathways that govern the appressorium formation and virulence of M. oryzae.

Phosphorylation-guarded light-harvesting complex II contributes to broad-spectrum blast resistance in rice.

Environmental conditions are key factors in the progression of plant disease epidemics. Light affects the outbreak of plant diseases, but the underlying molecular mechanisms are not well understood. Here, we report that the light-harvesting complex II protein, LHCB5, from rice is subject to light-induced phosphorylation during infection by the rice blast fungus Magnaporthe oryzae We demonstrate that single-nucleotide polymorphisms (SNPs) in the LHCB5 promoter control the expression of LHCB5, which in turn correlates with the phosphorylation of LHCB5. LHCB5 phosphorylation enhances broad-spectrum resistance of rice to M. oryzae through the accumulation of reactive oxidative species (ROS) in the chloroplast. We also show that LHCB5 phosphorylation-induced resistance is inheritable. Our results uncover an immunity mechanism mediated by phosphorylation of light-harvesting complex II.