Arachidonic acid activates NLRP3 inflammasome in MDSCs via FATP2 to promote post-transplant tumour recurrence in steatotic liver grafts.

Background & Aims: The steatotic grafts have been applied in liver transplantation frequently owing to the high incidence of non-alcoholic fatty liver disease. However, fatty livers are vulnerable to graft injury. Myeloid-derived suppressor cell (MDSC) recruitment during liver graft injury promotes tumour recurrence. Lipid metabolism exerts the immunological influence on MDSCs in tumour progression. Here, we aimed to explore the role and mechanism of inflammasome activation in MDSCs induced by lipid metabolism during fatty liver graft injury and the subsequent effects on tumour recurrence. Methods: MDSC populations and nucleotide-binding oligomerisation domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome levels were investigated in a clinical cohort and a rat liver transplantation model. The mechanism of NLRP3 activation by specific fatty acids was explored in mouse hepatic ischaemia/reperfusion injury (IRI) with tumour recurrence model and in vitro studies. Results: MDSC populations and NLRP3 levels were increased with higher tumour recurrent rate in patients using steatotic grafts. NLRP3 was upregulated in MDSCs with lipid accumulation post mouse fatty liver IRI. Mechanistically, arachidonic acid was discovered to activate NLRP3 inflammasome in MDSCs through fatty acid transport protein 2 (FATP2), which was identified by screening lipid uptake receptors. The mitochondrial dysfunction with enhanced reactive oxygen species bridged arachidonic acid uptake and NLRP3 activation in MDSCs, which subsequently stimulated CD4+ T cells producing more IL-17 in fatty liver IRI. Blockade of FATP2 inhibited NLRP3 activation in MDSCs, IL-17 production in CD4+ T cells, and the tumour recurrence post fatty liver IRI. Conclusions: During fatty liver graft injury, arachidonic acid activated NLRP3 inflammasome in MDSCs through FATP2, which subsequently stimulated CD4+ T cells producing IL-17 to promote tumour recurrence post transplantation. Impact and implications: The high incidence of non-alcoholic fatty liver disease resulted in the frequent application of steatotic donors in liver transplantation. Our data showed that the patients who underwent liver transplantation using fatty grafts experienced higher tumour recurrence. We found that arachidonic acid activated NLRP3 inflammasome in MDSCs through FATP2 during fatty liver graft injury, which led to more IL-17 secretion of CD4+ T cells and promoted tumour recurrence post transplantation. The inflammasome activation by aberrant fatty acid metabolism in MDSCs bridged the acute-phase fatty liver graft injury and liver tumour recurrence.

Glutathione S-transferase A2 promotes hepatocellular carcinoma recurrence after liver transplantation through modulating reactive oxygen species metabolism.

Hepatocellular carcinoma (HCC) recurrence after liver transplantation remains a significant clinical problem. Ischemia-reperfusion injury (IRI) occurred inevitably at the early phase after liver transplantation (LT) spawns a significant risk of HCC recurrence. However, their linkage and IRI-derived risk factors for HCC recurrence remain exclusive. Understanding the mechanism of post-transplantation hepatic injury could provide new strategies to prevent the later event of HCC recurrence. We demonstrated that glutathione S-transferase A2 (GSTA2) expression was significantly associated with early phase hepatic and systemic injury and ROS level after liver transplantation. Early phase circulating GSTA2 (EPCGSTA2) protein was a significant predictor of HCC recurrence and survival. Heterogeneous single nucleotide polymorphism at G335C of GSTA2 was significantly associated with poor survival of HCC recipients. Enhancement of GSTA2 could protect HCC cells against H2O2-induced cell death by compensating for the elevated ROS stress. We also demonstrated that GSTA2 played crucial roles in regulating the ROS-associated JNK and AKT signaling pathways and ROS metabolism in HCCs in responding to a dynamic ROS environment. Functionally, endogenous or exogenous upregulation of GSTA2 could promote HCC growth and invasion through activating the epithelial-mesenchymal-transition process. Targeted inhibition of GSTA2 could suppress HCC growth and metastasis. In conclusion, GSTA2 could be a novel prognostic and therapeutic target to combat HCC recurrence after liver transplantation.

Clinical significance and functional role of transmembrane protein 47 (TMEM47) in chemoresistance of hepatocellular carcinoma.

Chemoresistance is the main cause of chemotherapy failure in patients with hepatocellular carcinoma (HCC). The gene encoding transmembrane protein 47 (TMEM47) was previously identified to be significantly upregulated in HCC cell lines with acquired chemoresistance. The aim of the present study was to characterize the clinical significance and function of TMEM47 in HCC chemoresistance. The results demonstrated that the TMEM47 expression levels in the tumors of patients not responding to cisplatin­based transarterial chemoembolization (TACE) treatment was significantly higher compared with those in patients who responded to TACE treatment. Moreover, analyses from clinical samples and HCC cell lines indicated that TMEM47 expression may be upregulated in HCC in response to cisplatin treatment. Furthermore, the TMEM47 mRNA expression levels were positively correlated with the degree of cisplatin resistance of HCC cells. Overexpression of TMEM47 in HCC cells significantly promoted cisplatin resistance. The present study also demonstrated that targeted inhibition of TMEM47 could significantly reduce cisplatin resistance of cisplatin­resistant HCC cells via enhancing caspase­mediated apoptosis. In addition, targeted inhibition of TMEM47 enhanced the sensitivity of cisplatin­resistant cells to cisplatin via suppressing cisplatin­induced activation of the genes involved in drug efflux and metabolism. The present study also validated that TMEM47 expression was significantly correlated with multidrug resistance­associated protein 1 in patients with HCC who received TACE treatment. In conclusion, the findings of the present study demonstrated that TMEM47 may be a useful biomarker for predicting the response to chemotherapy and a potential therapeutic target for overcoming HCC chemoresistance.

A combination of depression and liver Qi stagnation and spleen deficiency syndrome using a rat model.

A syndrome (Zheng in Chinese) plays a critical role in disease identification, diagnosis, and treatment in traditional Chinese medicine (TCM). Clinically, the liver Qi stagnation and spleen deficiency syndrome (LQSSDS) is one of the most common syndrome patterns. Over the past few decades, several animal models have been developed to understand the potential mechanisms of LQSSDS, but until now, simulation of the syndrome is still unclear. Recently, several studies have confirmed that an animal model combining a disease and a syndrome is appropriate for simulating TCM syndromes. Overlapping previous studies have reported that depression is highly associated with LQSSDS; hence, we attempted to develop a rat model combining depression and LQSSDS. We exposed the rats to different durations of chronic unpredictable mild stress (CUMS). Subsequently, the evaluation indicators at macrolevel consisted of behavioral tests including open field test, sucrose preference test, and forced swim test, food intake, body weight, white adipose tissue, fecal water content, visceral hypersensitivity, and small bowel transit, and the evaluation indicators at microlevel included changes of hypothalamic-pituitary-adrenal axis. Serum D-xylose absorption was used to comprehensively confirm and assess whether the model was successful during the CUMS-induced process. The results showed that rats exposed to 6-week CUMS procedure exhibited significantly similar traits to the phenotypes of LQSSDS and depression. This study provided a new rat model for the LQSSDS and could potentially lead to a better understanding of the pathophysiology of LQSSDS and the development of new drugs for this syndrome.

Pancreas grafts for transplantation from donors with hypertension: an analysis of the scientific registry of transplant recipients database.

BACKGROUND: With the rising demands for pancreas transplantation, surgeons are trying to extend the donors pool and set up a more appropriate assessment system. We aim to evaluate the effect of donor hypertension on recipient overall and graft survival rates. METHODS: Twenty-four thousand one hundred ninety-two pancreas transplantation patients from the Scientific Registry of Transplant Recipients database were subdivided into hypertension group (HTN, n = 1531) and non-hypertension group (non-HTN, n = 22,661) according to the hypertension status of donors. Recipient overall and graft survival were analyzed and compared by log rank test, and hazard ratios of predictors were estimated using Cox proportional hazard models. RESULTS: Patient overall and graft survival of non-HTN group were higher than that of the HTN group (both p < 0.001). The duration of hypertension negatively influenced both overall and graft survival rates (both p < 0.001). Multivariate analyses demonstrated that hypertension was an independent factor for reduced survival (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.01-1.18; p < 0.001). Other independent factors included recipient body mass index (HR, 1.02; 95% CI, 1.01-1.05; p < 0.001) and transplant type (pancreas after kidney transplants / pancreas transplant alone vs. simultaneous pancreas-kidney transplants; HR, 1.41; 95% CI, 134-1.55; p < 0.001). CONCLUSIONS: Donor hypertension is an independent factor for recipient survival after pancreas transplantation and could be considered in donor selection as well as post-transplant surveillance in clinical practice.

Relationship between Insulin Levels and Nonpsychotic Dementia: A Systematic Review and Meta-Analysis.

Objectives: To explore the relationship between insulin levels and nonpsychotic dementia. Methods: Six electronic databases (PubMed, Cochrane, SCI, CNKI, VIP, and Wanfang) were searched from January 1, 2007, to March 1, 2017. Experimental or observational studies that enrolled people with nonpsychotic dementia or abnormal insulin levels in which insulin levels or MMSE scores (events in nonpsychotic dementia) were the outcome measures. Random-effects models were chosen for this meta-analysis. Sample size, mean, s.d., and events were primarily used to generate effect sizes (with the PRIMA registration number CRD42017069860). Results: 50 articles met the final inclusion criteria. Insulin levels in cerebrospinal fluid were lower (Hedges' g = 1.196, 95% CI = 0.238 to 2.514, and P = 0.014), while the levels in peripheral blood were higher in nonpsychotic dementia patients (Hedges' g = 0.853 and 95% CI = 0.579 to 1.127), and MMSE scores were significantly lower in the high insulin group than in the healthy control group (Hedges' g = 0.334, 95% CI = 0.249 to 0.419, and P = 0.000). Conclusions: Our comprehensive results indicate that blood insulin levels may increase in patients with nonpsychotic dementia.