CycC1;1-WRKY75 complex-mediated transcriptional regulation of SOS1 controls salt stress tolerance in Arabidopsis.

SALT OVERLY SENSITIVE1 (SOS1) is a key component of plant salt tolerance. However, how SOS1 transcription is dynamically regulated in plant response to different salinity conditions remains elusive. Here, we report that C-type Cyclin1;1 (CycC1;1) negatively regulates salt tolerance by interfering with WRKY75-mediated transcriptional activation of SOS1 in Arabidopsis (Arabidopsis thaliana). Disruption of CycC1;1 promotes SOS1 expression and salt tolerance in Arabidopsis because CycC1;1 interferes with RNA polymerase II recruitment by occupying the SOS1 promoter. Enhanced salt tolerance of the cycc1;1 mutant was completely compromised by an SOS1 mutation. Moreover, CycC1;1 physically interacts with the transcription factor WRKY75, which can bind to the SOS1 promoter and activate SOS1 expression. In contrast to the cycc1;1 mutant, the wrky75 mutant has attenuated SOS1 expression and salt tolerance, whereas overexpression of SOS1 rescues the salt sensitivity of wrky75. Intriguingly, CycC1;1 inhibits WRKY75-mediated transcriptional activation of SOS1 via their interaction. Thus, increased SOS1 expression and salt tolerance in cycc1;1 were abolished by WRKY75 mutation. Our findings demonstrate that CycC1;1 forms a complex with WRKY75 to inactivate SOS1 transcription under low salinity conditions. By contrast, under high salinity conditions, SOS1 transcription and plant salt tolerance are activated at least partially by increased WRKY75 expression but decreased CycC1;1 expression.

LNCHC directly binds and regulates YBX1 stability to ameliorate metabolic dysfunction-associated steatotic liver disease progression.

BACKGROUND AND AIMS: Metabolic dysfunction-associated steatotic liver disease (MASLD) represents the foremost cause of chronic liver disease, yet its underlying mechanisms remain elusive. Our group previously discovered a novel long non-coding RNA (lncRNA) in rats, termed lncHC and its human counterpart, LNCHC. This study aimed to explore the role of LNCHC in the progression of MASLD. METHODS: RNA-binding proteins bound to LNCHC were searched by mass spectrometry. The target genes of LNCHC and Y-Box binding protein 1 (YBX1) were identified by RNA-seq. MASLD animal models were utilised to examine the roles of LNCHC, YBX1 and patatin-like phospholipase domain containing 3 (PNPLA3) in MASLD progression. RESULTS: Here, we identified LNCHC as a native restrainer during MASLD development. Notably, LNCHC directly binds YBX1 and prevents protein ubiquitination. Up-regulation of YBX1 then stabilises PNPLA3 mRNA to alleviate lipid accumulation in hepatocytes. Furthermore, both cell and animal studies demonstrate that LNCHC, YBX1 and PNPLA3 function to improve hepatocyte lipid accumulation and exacerbate metabolic dysfunction-associated steatohepatitis development. CONCLUSIONS: In summary, our findings unveil a novel LNCHC functionality in regulating YBX1 and PNPLA3 mRNA stability during MASLD development, providing new avenues in MASLD treatment.

Coprococcus protects against high-fat diet-induced nonalcoholic fatty liver disease in mice.

AIMS: The incidence of nonalcoholic fatty liver disease (NAFLD) is increasing annually, leading to substantial medical and health burdens. Numerous studies have demonstrated the potential effectiveness of intestinal probiotics as a treatment strategy for NAFLD. Therefore, the objective of this study is to identify a probiotic for the treatment of NAFLD. METHODS AND RESULTS: In this study, blood and fecal samples were collected from 41 healthy volunteers and 44 patients diagnosed with NAFLD. Analysis of the 16S rDNA sequencing data and quantitative real-time PCR (RT-qPCR) revealed a significant reduction in the abundance of Coprococcus in NAFLD patients. Subsequent animal experiments demonstrated that Coprococcus was able to effectively reverse liver lipid accumulation, inflammation, and fibrosis induced by a high-fat diet (HFD) in mice. CONCLUSIONS: This study provides the first in vivo evidence that Coprococcus is a beneficial bacterium capable of preventing NAFLD and has the same probiotic effect in mice as Lactobacillus GG (LGG), a positive control. Therefore, Coprococcus has the potential to serve as a probiotic for the prevention and treatment of NAFLD in humans.

Abscisic acid facilitates phosphate acquisition through the transcription factor ABA INSENSITIVE5 in Arabidopsis.

Low phosphate (LP) in soil is a common nutrient stress that severely restricts agricultural production, but the role, if any, of the major stress phytohormone abscisic acid (ABA) in plant phosphate (Pi) starvation responses remains elusive. Here, we report that LP-induced ABA accumulation promotes Pi uptake in an ABA INSENSITIVE5 (ABI5)-dependent manner in Arabidopsis thaliana. LP significantly activated plant ABA biosynthesis, metabolism, and stress responses, suggesting a role of ABA in the plant response to Pi availability. LP-induced ABA accumulation and expression of two major high-affinity phosphate transporter genes PHOSPHATE TRANSPORTER1;1/1;4 (PHT1;1/1;4) were severely impaired in a mutant lacking BETA-GLUCOSIDASE1 (BG1), which converts conjugated ABA to active ABA, and the mutant had shorter roots and less Pi content than wild-type plants under LP conditions. Moreover, a mutant of ABI5, which encodes a central transcription factor in ABA signaling, also exhibited suppressed root elongation and had reduced Pi content under LP conditions. ABI5 facilitated Pi acquisition by activating the expression of PHT1;1 by directly binding to its promoter, while overexpression of PHT1;1 completely rescued its Pi content under LP conditions. Together, our findings illustrate a molecular mechanism by which ABA positively modulates phosphate acquisition through ABI5 in the Arabidopsis response to phosphate deficiency.

CycC1;1 negatively modulates ABA signaling by interacting with and inhibiting ABI5 during seed germination.

Regulation of seed germination is important for plant survival and propagation. ABSCISIC ACID (ABA) INSENSITIVE5 (ABI5), the central transcription factor in the ABA signaling pathway, plays a fundamental role in the regulation of ABA-responsive gene expression during seed germination; however, how ABI5 transcriptional activation activity is regulated remains to be elucidated. Here, we report that C-type Cyclin1;1 (CycC1;1) is an ABI5-interacting partner affecting the ABA response and seed germination in Arabidopsis (Arabidopsis thaliana). The CycC1;1 loss-of-function mutant is hypersensitive to ABA, and this phenotype was rescued by mutation of ABI5. Moreover, CycC1;1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes including ABI5 itself by occupying their promoters and disrupting RNA polymerase II recruitment; thus the cycc1;1 mutant shows increased expression of ABI5 and genes downstream of ABI5. Furthermore, ABA reduces the interaction between CycC1;1 and ABI5, while phospho-mimic but not phospho-dead mutation of serine-42 in ABI5 abolishes CycC1;1 interaction with ABI5 and relieves CycC1;1 inhibition of ABI5-mediated transcriptional activation of downstream target genes. Together, our study illustrates that CycC1;1 negatively modulates the ABA response by interacting with and inhibiting ABI5, while ABA relieves the CycC1;1 interaction with and inhibition of ABI5 to activate ABI5 activity for the ABA response, thereby inhibiting seed germination.

[Research progress on mechanism and preventive measures of retrograde ejaculation after benign prostatic hyperplasia surgery].

Benign prostatic hyperplasia (BPH) is a common disease in middle-aged and elderly men. It's first-line therapy is drugs. But with the progression of the disease or side effects of drugs, surgical treatment will become a better choice. However, either transurethral resection of the prostate, the standard procedure, or enucleation or resection of the prostate based on various laser platforms or plasma technologies cause a high incidence of retrograde ejaculation in their postoperative follow-up. In the past, retrograde ejaculation was usually regarded as the cost of benign prostatic hyperplasia surgery. In recent years, with the continuous improvement of surgical skills and the emergence of new techniques, retrograde ejaculation has aroused the attention of clinicians. This article mainly introduces the mechanism of retrograde ejaculation after benign prostatic hyperplasia surgery and the methods to reduce the incidence of retrograde ejaculation after surgery. These methods mainly include various modified surgery, as well as novel minimally invasive techniques such as prostate embolization and prostatic urethral lift.

Maize PHYTOMELATONIN RECEPTOR1 functions in plant tolerance to osmotic and drought stress.

Phytomelatonin is a universal signal molecule that regulates plant growth and stress responses; however, only one receptor that can directly bind with and perceive melatonin signaling has been identified so far, namely AtPMTR1/CAND2 in Arabidopsis. Whether other plants contain a similar receptor and, if so, how it functions is still unknown. In this study, we identified a new phytomelatonin receptor in the monocot maize (Zea mays), and investigated its role in plant responses to osmotic and drought stress. Using homology searching, we identified a plasma membrane-localized protein, Zm00001eb214610/ZmPMTR1, with strong binding activity to melatonin as a potential phytomelatonin receptor in maize. Overexpressing ZmPMTR1 in Arabidopsis Col-0 promoted osmotic stress tolerance, and rescued osmotic stress sensitivity of the Arabidopsis cand2-1 mutant. Furthermore, ZmPMTR1 also largely rescued defects in melatonin-induced stomatal closure in the cand2-1 mutant, thereby reducing water loss rate and increasing tolerance to drought stress. In addition, we identified a maize mutant of ZmPMTR1, EMS4-06e2fl, with a point-mutation causing premature termination of protein translation, and found that this mutant had lower leaf temperatures, increased rate of water loss, and enhanced drought stress sensitivity. Thus, we present ZmPMTR1 as the first phytomelatonin receptor to be identified and examined in a monocot plant, and our results indicate that it plays an important function in the response of maize to drought stress.

Inhibition of miR-188-5p alleviates hepatic fibrosis by significantly reducing the activation and proliferation of HSCs through PTEN/PI3K/AKT pathway.

Persistent hepatic damage and chronic inflammation in liver activate the quiescent hepatic stellate cells (HSCs) and cause hepatic fibrosis (HF). Several microRNAs regulate the activation and proliferation of HSCs, thereby playing a critical role in HF progression. Previous studies have reported that miR-188-5p is dysregulated during the process of HF. However, the role of miR-188-5p in HF remains unclear. This study investigated the potential role of miR-188-5p in HSCs and HF. Firstly, we validated the miR-188-5p expression in primary cells isolated from liver of carbon tetrachloride (CCl4 )-induced mice, TGF-ß1-induced LX-2 cells, livers from 6-month high-fat diet (HFD)-induced rat and 4-month HFD-induced mice NASH models, and human non-alcoholic fatty liver disease (NAFLD) patients. Furthermore, we used miR-188-5p inhibitors to investigate the therapeutic effects of miR-188-5p inhibition in the HFD + CCl4 induced in vivo model and the potential role of miR-188-5p in the activation and proliferation of HSCs. This present study reported that miR-188-5p expression is significantly increased in the human NAFLD, HSCs isolated from liver of CCl4 induced mice, and in vitro and in vivo models of HF. Mimicking the miR-188-5p resulted in the up-regulation of HSC activation and proliferation by directly targeting the phosphatase and tensin homolog (PTEN). Moreover, inhibition of miR-188-5p reduced the activation and proliferation markers of HSCs through PTEN/AKT pathway. Additionally, in vivo inhibition of miR-188-5p suppressed the HF parameters, pro-fibrotic and pro-inflammatory genes, and fibrosis. Collectively, our results uncover the pro-fibrotic role of miR-188-5p. Furthermore, we demonstrated that miR-188-5p inhibition decreases the severity of HF by reducing the activation and proliferation of HSCs through PTEN/AKT pathway.

CAND2/PMTR1 Is Required for Melatonin-Conferred Osmotic Stress Tolerance in Arabidopsis.

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.

Comparative study of tapered versus conventional cylindrical balloon for stent implantation in stenotic tapered artery.

The natural tapering of coronary arteries often creates a dilemma for optimal balloon sizing during stenting. The influence of different balloon types, namely, a tapered balloon and a conventional cylindrical balloon, on the mechanical performance of the stent as well as arterial mechanics was investigated via the finite element method. Stent free-expansion and stent deployment in a stenotic tapered artery were investigated numerically. The biomechanical behavior of the two balloon types was compared in terms of stent foreshortening, stent deformation, stent stress distribution, and arterial wall stress distribution. Results indicate that balloon types affect the transient behavior of the stent and the arterial mechanics. Specifically, a tapered balloon could maintain the natural tapering of the coronary artery after stent expansion. In contrast to a cylindrical balloon, tapered balloon also mitigated the foreshortening of the stent (7.69%) as well as the stress concentration in the stent and artery (8.61% and 4.17%, respectively). Hence, tapered balloons should be used in tapered arteries as they may result in low risk of artery injury. This study might provide insights for improved balloon choice and presurgical planning.

[Daily NO2 Simulation Research Based on Automatic Machine Learning Ensemble Models].

To understand the spatial distribution of NO2 near the surface, we utilized measured data from NO2 monitoring stations and combined it with column concentration data from the Tropospheric Monitoring Instrument （TROPOMI）, taking the Yangtze River Delta region as the study area. We considered the impact of factors such as population, elevation, and meteorological conditions on NO2 levels. We used automated machine learning to select five machine-learning algorithms with high simulation accuracy, namely ET, RF, XGBoost, LightGBM, and Catboost, and then integrated these five algorithms using the Stacking model to simulate the daily NO2 concentration in the Yangtze River Delta region from March 2020 to February 2021. The results indicated that the RMAE and MAE values of the Stacking ensemble model were 7.078 and 5.270, respectively, which outperformed the single algorithms of ET, RF, XGBoost, LightGBM, and Catboost. The spatial distribution of high NO2 concentrations in the Yangtze River Delta region, consisting of three provinces and one municipality, exhibited a U-shaped pattern with the convergence point located at the intersection of the three provinces, extending towards the southwest. Notably, urban pollution was particularly significant in the urban agglomerations centered around Shanghai, Hangzhou, Nanjing, and Hefei. There were 27 cities that exceeded the national standard daily limit. Changzhou was the city with the most serious NO2 pollution, with the NO2 concentration exceeding the standard for 14 d, followed by Shanghai, with 13 d. In terms of seasonal variation, the order of severity was as follows： winter, autumn, spring, and summer, with the least NO2 pollution occurring on July 9th during the summer, and the most severe NO2 pollution was observed on December 23rd during the winter.

Hepatocyte-specific NR5A2 deficiency induces pyroptosis and exacerbates non-alcoholic steatohepatitis by downregulating ALDH1B1 expression.

Nonalcoholic steatohepatitis (NASH) is a prevalent chronic disease, yet its exact mechanisms and effective treatments remain elusive. Nuclear receptor subfamily 5 group A member 2 (NR5A2), a transcription factor closely associated with cholesterol metabolism in the liver, has been hindered from comprehensive investigation due to the lethality of NR5A2 loss in cell lines and animal models. To elucidate the role of NR5A2 in NASH, we generated hepatocyte-specific knockout mice for Nr5a2 (Nr5a2HKO) and examined their liver morphology across different age groups under a regular diet. Furthermore, we established cell lines expressing haploid levels of NR5A2 and subsequently reintroduced various isoforms of NR5A2. In the liver of Nr5a2HKO mice, inflammation and fibrosis spontaneously emerged from an early age, independent of lipid accumulation. Pyroptosis occurred in NR5A2-deficient cell lines, and different isoforms of NR5A2 reversed this form of cell death. Our findings unveiled that inhibition of NR5A2 triggers pyroptosis, a proinflammatory mode of cell death primarily mediated by the activation of the NF-κB pathway induced by reactive oxygen species (ROS). As a transcriptionally regulated molecule of NR5A2, aldehyde dehydrogenase 1 family member B1 (ALDH1B1) participates in pyroptosis through modulation of ROS level. In conclusion, the diverse isoforms of NR5A2 exert hepatoprotective effects against NASH by maintaining a finely tuned balance of ROS, which is contingent upon the activity of ALDH1B1.

PDCD4 deficiency in hepatocytes exacerbates nonalcoholic steatohepatitis through enhanced MHC class II transactivator expression.

Nonalcoholic steatohepatitis (NASH) is a primary cause of liver cirrhosis and hepatocellular carcinoma, presenting a significant and unmet medical challenge. The necessity to investigate the molecular mechanisms underlying NASH is highlighted by the observed decrease in programmed cell death 4 (PDCD4) expression in NASH patients, suggesting that PDCD4 may play a protective role in maintaining liver health. In this study, we identify PDCD4 as a natural inhibitor of NASH development in mice. The absence of PDCD4 leads to the spontaneous progression of NASH. Notably, PDCD4-deficient hepatocytes display elevated major histocompatibility complex class II (MHCII) expression due to CIITA activation, indicating that PCDC4 prevents the abnormal transformation of hepatocytes into antigen-presenting cells (APCs). Cell co-culture experiments reveal that hepatocytes lacking PDCD4, which resemble APCs, can directly activate CD4+ T cells by presenting multiple peptides, resulting in the release of inflammatory factors. Additionally, both cellular and animal studies show that CIITA promotes lipid accumulation in hepatocytes and exacerbates NASH progression. In summary, our findings reveal a novel role of PDCD4 in regulating CIITA and MHCII expression during NASH development, offering new therapeutic approaches for NASH treatment.

Leucine aminopeptidase 3:a promising serum biomarker candidate for nonalcoholic steatohepatitis diagnosis.

BACKGROUND & AIMS: Nonalcoholic steatohepatitis (NASH) is a highly prevalent liver disease that lacks targeted therapeutic drugs and non-invasive diagnostic methods. Increasing evidence demonstrated that aberrant expression of leucine aminopeptidase 3 (LAP3) is involved in NASH. Herein, we aimed to investigate whether LAP3 can be a promising serum biomarker for NASH diagnosis. METHODS: Liver tissues and serum from NASH rats, serum from NASH patients, and liver biopsies from chronic hepatitis B (CHB) patients combined with NASH (CHB+NASH) were obtained to evaluate the LAP3 level. Correlation analysis was conducted to evaluate the association between LAP3 expression and clinical indexes in CHB patients and CHB+NASH patients. ROC curve analysis of LAP3 in the serum and liver was applied to assess whether LAP3 can be a promising biomarker for NASH diagnosis. RESULTS: LAP3 was significantly upregulated in serum and hepatocytes of NASH rats and patients with NASH. Correlation analysis revealed that LAP3 in the liver of CHB patients and CHB+NASH patients showed a strong positive correlation with lipidome indicators total cholesterol (TC) and triglyceride (TG), and liver fibrosis indicator hyaluronic acid (HA), which showed a negative correlation with the international normalized ratio of prothrombin coagulation (INR) and liver injury indicator aspartate aminotransferase (AST). For NASH, the diagnostic accuracy of ALT > LAP3 > AST, the sensitivity LAP3 (0.87) > ALT (0.5957) > AST (0.2941), the specificity AST (0.975) > ALT (0.9) > LAP3 (0.5). CONCLUSION: Our data urge that LAP3 can serve as a promising serum biomarker candidate for NASH diagnosis.

Secondary injury and pro-inflammatory macrophages increase osteophyte growth and fracture healing in canine atrophic nonunion.

OBJECTIVES: In this study, we used a canine high-energy fracture model to examine the relationship between the early inflammatory reaction in adjacent tissues and the ability for osteophyte growth, aiming to identify causes that lead to atrophic nonunion inflammatory disease and to provide new strategies for prevention and treatment. MATERIALS AND METHODS: Forty-eight models of canine femoral high energy fractures were prepared and randomly divided into groups A and B (n=24 in each group). Dogs in both groups underwent open reduction and 6-hole plate internal fixation. Group A models were re-opened, and muscle near the bone was scraped at 14 d after the operation. On days 3, 17, 28, and 42 after fracture, 6 experimental dogs were euthanized per group, and the fracture specimens were used to examine pathologic changes and the growth of callus in the fractured end and its adjacent tissues. RESULTS: At day 14, neutrophil infiltration, with no macrophage recruitment, no mesenchymal cell proliferation, and no fracture healing cascade were observed in the adjacent tissues of both groups. Immediately after the second injury was performed in group A, many macrophages were seen, and mesenchymal cells proliferated, which initiated vigorous osteophyte growth and led to osteophyte healing. Atrophic nonunion was observed in group B without secondary injury. CONCLUSION: Macrophage recruitment deficiency in adjacent soft tissue in early surgery for high-energy fractures may be an important cause of atrophic nonunion. Secondary injury inflammation can effectively recruit mononuclear macrophages, generate osteoclasts, re-initiate the growth of osteophytes, and promote fracture healing.

Pdcd4 promotes lipid deposition by attenuating PPARα-mediated fatty acid oxidation in hepatocytes.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in hepatocytes. The involvement of programmed cell death 4 (Pdcd4) in inflammation and metabolic diseases has been widely reported. However, the precise regulatory role of Pdcd4 in hepatocytic lipid metabolism and NAFLD is not well known. RESEARCH DESIGN AND METHODS: We established a high-fat diet-induced NAFLD (HFD-NAFLD) rat model and a free fatty acids (FFAs)-treated cell model, and analyzed the expression and distribution of PDCD4. The lentivirus for Pdcd4 knockout and the vector for Pdcd4 overexpression were used to alter Pdcd4 expression in BRL 3A cells. Thereafter, lipid accumulation, FA metabolic gene expression, and peroxisome proliferator-activated receptor alpha (Pparα)-dependent peroxisomal ß-oxidation-related gene expression, especially that of the critical transcription factors and enzymes acyl-CoA oxidases 1-3 (Acox1-3), were detected both at the mRNA and protein levels. RESULTS: PDCD4 expression increased and it was mainly distributed in hepatocyte nuclei of the HFD-NAFLD rats. as well as the FFAs-treated CBRH-7919 and BRL 3A cell lines. Pdcd4 knockout significantly suppressed FFAs-induced lipid accumulation, and Pdcd4 overexpression accelerated FFAs-induced lipid accumulation in hepatocytes. Mechanistically, Pdcd4 negatively regulated the expression Pparα and Acox1-3. In addition, rescue experiments confirmed that Pparα knockdown could attenuate the expression of Acox1-3 in Pdcd4 knockout cells, which ultimately restored lipid deposition to normal levels. PPARα expression decreased in the liver of the HFD-NAFLD rats. The enrichment of PDCD4 in hepatocyte nuclei correlated with lower PPARα expression after FFAs treatment in vitro. CONCLUSION: Our results indicate that the abundance of PDCD4 under high-fat conditions facilitates hepatocellular lipid accumulation by decreasing PPARα-dependent FA peroxisomal ß-oxidation.

TGF-ß1 contributes to the hepatic inflammation in animal models with nonalcoholic steatohepatitis by Smad3/TLR2 signaling pathway.

Non-alcoholic fatty liver disease (NAFLD) is increasingly affecting human health and the economy worldwide due to various factors. Here, we found that the expression of TGF-ß1 and TLR2 was significantly up-regulated in liver samples from both rats and mice nonalcoholic steatohepatitis (NASH) models. By constructing corresponding cell model, we found that TGF-ß1 challenge can positively regulate the expression of TLR2 and p-Smad2/3, and the dual luciferase reporter gene system and EMSA assay confirmed the existence of Smad3 binding site (-916 ∼ -906) in the promoter region of TLR2. The overexpression and interference changes of Smad2/3 further verified the above experimental results. Taken together, these findings suggest that TGF-ß1 promotes TLR2 transcription and its target gene expression via Smad3, leading to malignant exacerbation of liver inflammation in NASH, which provides new insights into the treatment of NASH.

Cholesterol-induced leucine aminopeptidase 3 (LAP3) upregulation inhibits cell autophagy in pathogenesis of NAFLD.

OBJECTIVES: Leucine aminopeptidase 3 (LAP3), an M1 member of leucine aminopeptidase, was reported to be significantly upregulated in serum of nonalcoholic fatty liver disease (NAFLD) patients. However, the underlying mechanisms of LAP3 in NAFLD pathogenesis are still unknown. We aim to investigate the role of LAP3 in NAFLD pathogenesis and explore whether LAP3 has the potential to be a candidate biomarker in serum for NAFLD diagnosis. METHODS: Liver tissues and serum from NASH rats, serum from patients with NAFLD were obtained to evaluate the LAP3 expression. Detection of GSSG/GSH, intracellular reactive oxygen species (ROS), and LC3 expression by elevation/ reduction of LAP3 expression to determine the role of LAP3 in NAFLD pathogenesis. Finally, the correlation analysis was conducted to evaluate the association between LAP3 expression and clinical indexes of NAFLD. RESULTS: LAP3 expression was upregulated in hepatocytes and serum in E3 rats with NASH after 6-month HFD feeding. Cholesterol (CHO) dramatically upregulated LAP3 in LO2 cells, and then lead to negative regulation of autophagy. Moreover, LAP3 levels were also significantly increased in NAFLD patients compared to healthy controls. Correlation analysis revealed that serum LAP3 levels were positively correlated with TG, γ-glutamyltranspeptidase (GGT), and fasting blood glucose levels, while there was a negative correlation with HDL levels. CONCLUSIONS: The cholesterol-dependent upregulation of LAP3 in hepatocytes plays a critical role in the pathogenesis of NAFLD via inhibiting autophagy. Moreover, LAP3 could serve as a potential novel candidate biomarker for the diagnosis of NAFLD.

IFN-γ contributes to the hepatic inflammation in HFD-induced nonalcoholic steatohepatitis by STAT1ß/TLR2 signaling pathway.

Growing research evidence suggests that elevated TLR2 is closely related to the occurrence and development of nonalcoholic steatohepatitis (NASH). However, a little is known about its regulatory mechanism. Here, we found that IFN-γ and TLR2 expression is significantly upregulated in NASH associated rat liver specimens. Meanwhile, IFN-γ positively regulated the expression of TLR2 and its target genes in NR8383 rat macrophage cells in dose- & time-dependent manner. Importantly, IFN-γ also regulated the related transcriptional factors pSTAT1 and IRF1. Moreover, we identified that the DNA fragment from -1000 to -200 bp of the TLR2 promoter region is responsible for STAT1 binding, especially the STAT1-BS3 (-591∼-573 bp). Further investigation verified that STAT1ß is essential in this process, rather than STAT1α. Overall, our findings suggest that IFN-γ promotes TLR2 transcription and its target genes expression by STAT1ß. This leads to the hepatic inflammation vicious cycle in NASH and provides new potential targets for treating NASH.

Overexpressing the N-terminus of CATALASE2 enhances plant jasmonic acid biosynthesis and resistance to necrotrophic pathogen Botrytis cinerea B05.10.

Salicylic acid (SA) acts antagonistically to jasmonic acid (JA) in plant immunity. We previously reported that CATALASE2 (CAT2) promotes JA-biosynthetic acyl-CoA oxidase (ACX) activity to enhance plant resistance to necrotrophic Botrytis cinerea, and SA represses JA biosynthesis through inhibiting CAT2 activity, while the underlying mechanism remains to be further elucidated. Here, we report that the truncated CAT2 N-terminus (CAT2-N) interacts with and promotes ACX2/3, and CAT2-N-overexpressing plants have increased JA accumulation and enhanced resistance to B. cinerea B05.10, but compromised antagonism of SA on JA. Catalase inhibitor treatment or mutating CAT2 active amino acids abolished CAT2 H2 O2 -decomposing activity but did not affect its promotion of ACX2/3 activity via interaction. CAT2-N, a truncated protein with no catalase activity, interacted with and promoted ACX2/3. Overexpressing CAT2-N in Arabidopsis plants resulted in increased ACX activity, higher JA accumulation, and stronger resistance to B. cinerea B05.10 infection. Additionally, SA dramatically repressed JA biosynthesis and resistance to B. cinerea in the wild type but not in the CAT2-N-overexpressing plants. Together, our study reveals that CAT2-N can be utilized as an accelerator for JA biosynthesis during plant resistance to B. cinerea B05.10, and this truncated protein partly relieves SA repression of JA biosynthesis in plant defence responses.