Liver transplantation (LT) has become a standard treatment for end-stage liver diseases, and graft injury is intricately associated with poor prognosis. Granzyme B (GZMB) plays a vital role in natural killer (NK) cell biology, but whether NK-derived GZMB affects graft injury remains elusive. Through the analysis of single-cell RNA-sequencing data obtained from human LT grafts and the isolation of lymphocytes from mouse livers following ischemia-reperfusion injury (IRI), we demonstrated that 2NK cells with high expression of GZMB are enriched in patients and mice. Both systemically and liver-targeted depletion of NK cells led to a notable reduction in GZMB⁺ cell infiltration, subsequently resulting in diminished graft injury. Notably, the reconstitution of Il2rg ^-/- Rag2 ^-/- mice with purified Gzmb-KO NK cells demonstrated superior outcomes compared to those with wild-type NK cells. Crucially, global knockout of GZMB and pharmacological inhibition exhibited remarkable improvements in liver function in both mouse IRI and rat LT models. Moreover, a phosphorylated derivative of FDA-approved vidarabine was identified as an effective inhibitor of mouse GZMB activity by molecular dynamics, which could provide a potential avenue for therapeutic intervention. Therefore, targeting NK cell-derived GZMB during the LT process suggests potential therapeutic strategies to improve post-transplant outcomes.

Tacrolimus (TAC), also called FK506, is one of the classical immunosuppressants to prevent allograft rejection after liver transplantation. However, it has been proved to be associated with post-transplant hyperlipemia. The mechanism behind this is unknown, and it is urgent to explore preventive strategies for hyperlipemia after transplantation. Therefore, we established a hyperlipemia mouse model to investigate the mechanism, by injecting TAC intraperitoneally for eight weeks. After TAC treatment, the mice developed hyperlipemia (manifested as elevated triglyceride (TG) and low-density lipoprotein cholesterol (LDL-c), as well as decreased high-density lipoprotein cholesterol (HDL-c)). Accumulation of lipid droplets was observed in the liver. In addition to lipid accumulation, TAC induced inhibition of the autophagy-lysosome pathway (microtubule-associated protein 1 light chain 3β (LC3B) II/I and LC3B II/actin ratios, transcription factor EB (TFEB), protein 62 (P62), and lysosomal-associated membrane protein 1 (LAMP1)) and downregulation of fibroblast growth factor 21 (FGF21) in vivo. Overexpression of FGF21 may reverse TAC-induced TG accumulation. In this mouse model, the recombinant FGF21 protein ameliorated hepatic lipid accumulation and hyperlipemia through repair of the autophagy-lysosome pathway. We conclude that TAC downregulates FGF21 and thus exacerbates lipid accumulation by impairing the autophagy-lysosome pathway. Recombinant FGF21 protein treatment could therefore reverse TAC-caused lipid accumulation and hypertriglyceridemia by enhancing autophagy.
Animals ; Mice ; Tacrolimus ; Liver ; Cholesterol, LDL ; Autophagy ; Disease Models, Animal

Objective:To investigate the correlation between RNF213 gene p. R4810K polymorphism and posterior cerebral artery involvement in Chinese children with familial moyamoya disease.Methods:Children with familial moyamoya disease admitted to the Department of Neurosurgery, the Fifth Medical Center of PLA General Hospital from August 2004 to June 2018 were enrolled, and they were divided into posterior cerebral artery involved group and posterior cerebral artery uninvolved group. RNF213 gene p. R4810K single nucleotide polymorphism was detected. Multivariate logistic regression analysis was used to determine the independent risk factors for posterior cerebral artery involvement. Results:A total of 65 children with familial moyamoya disease were enrolled. Their age was 6.98±4.46 years and 37 (56.9%) were male. The first symptom of 55 children (84.6%) was cerebral ischemia, and 37 (56.9%) involved posterior cerebral artery. There were 3 (4.6%) children with p. R4810K AA genotype, 26 (40.0%) with GA genotype, and 36 (55.4%) with GG genotype. The p. R4810K genotype distribution in the posterior cerebral artery involved group was statistically different from that in the uninvolved group (GA+ AA genotype: 56.8% vs. 28.6%; χ2=5.124, P=0.024), and there were no statistical difference in gender, age, first symptom, and genetic pattern. Multivariate logistic regression analysis showed that after adjusting the first onset age and gender, p. R4810K G>A mutation was the only independent risk factor for posterior cerebral artery involvement (odds ratio 3.240, 95% confidence interval 1.082-9.705; P=0.020). Conclusion:The p. R4810K polymorphism of RNF213 gene is associated with posterior cerebral artery involvement in Chinese children with familial moyamoya disease.

Coronavirus disease 2019 (COVID-19), caused by the 2019 novel coronavirus (2019-nCoV), is spreading on a large scale in China. COVID-19 mainly affects the respiratory system and cause symptoms such as severe hypoxemia and high fever. At present, there is no specific treatment drug, and patients' autoimmunity is closely related to disease prognosis. The brain tissue of patients with moyamoya disease is in a state of ischemia and hypoxia for a long time. Hypoxemia and high fever will aggravate the cerebral ischemia and hypoxia in patients with moyamoya disease, and patients with moyamoya disease may also have autoimmune abnormalities. Because people with moyamoya disease are also likely to have COVID-19 and COVID-19 can cause many conditions that may aggravate the symptoms of patients with moyamoya disease, which brings new problems and challenges to the clinical diagnosis and treatment of moyamoya disease. In this article, the diagnosis and treatment process and prevention and control measures of patients with moyamoya disease under the current epidemic situation are thought, and the key issues in the treatment of patients with moyamoya disease after suffering from COVID-19 are sorted out. It is hoped to provide reference for the diagnosis and treatment of moyamoya disease under the COVID-19 epidemic situation.