End-stage liver diseases,such as cirrhosis and liver cancer caused by hepatitis B,are often combined with hepatic encephalopathy(HE);ammonia poisoning is posited as one of its main pathogenesis mechanisms.Ammonia is c...End-stage liver diseases,such as cirrhosis and liver cancer caused by hepatitis B,are often combined with hepatic encephalopathy(HE);ammonia poisoning is posited as one of its main pathogenesis mechanisms.Ammonia is closely related to autophagy,but the molecular mechanism of ammonia’s regulatory effect on autophagy in HE remains unclear.Sialylation is an essential form of glycosylation.In the nervous system,abnormal sialylation affects various physiological processes,such as neural development and synapse formation.ST3 β-galactoside α2,3-sialyltransferase 6(ST3GAL6)is one of the significant glycosyltransferases responsible for addingα2,3-linked sialic acid to substrates and generating glycan structures.We found that the expression of ST3GAL6 was upregulated in the brains of mice with HE and in astrocytes after ammonia induction,and the expression levels of α2,3-sialylated glycans and autophagy-related proteins microtubule-associated protein light chain 3(LC3)and Beclin-1 were upregulated in ammonia-induced astrocytes.These findings suggest that ST3GAL6 is related to autophagy in HE.Therefore,we aimed to determine the regulatory relationship between ST3GAL6 and autophagy.We found that silencing ST3GAL6 and blocking or degrading α2,3-sialylated glycans by way of Maackia amurensis lectin-II(MAL-II)and neuraminidase can inhibit autophagy.In addition,silencing the expression of ST3GAL6 can downregulate the expression of heat shock proteinβ8(HSPB8)and Bcl2-associated athanogene 3(BAG3).Notably,the overexpression of HSPB8 partially restored the reduced autophagy levels caused by silencing ST3GAL6 expression.Our results indicate that ST3GAL6 regulates autophagy through the HSPB8-BAG3 complex.展开更多
文摘目的:研究半乳凝素3(galectins-3,Gal-3)和5脂氧合酶(5-lipoxygenase,5-LOX)在胰腺癌中的表达及其关系。方法:收集胰腺癌44例组织及其配对的癌旁组织,采用RT-PCR检测Gal-3和5-LOX的m RNA表达情况;采用免疫组织化学染色法检测Gal-3和5-LOX的蛋白表达及分布。结果:Gal-3和5-LOX在胰腺癌组织中的m RNA表达分别为40例(90.9%)和38例(86.4%),均明显高于配对的癌旁组织5例(11.4%)和7例(15.9%),两者比较差异有统计学意义(P<0.05)。有淋巴结转移和病理分期Ⅱ期胰腺癌组织中Gal-3和5-LOX的阳性表达率高于无淋巴结转移和病理分期Ⅰ期(P<0.05),且Gal-3和5-LOX m RNA表达与患者性别、年龄、肿瘤部位、肿瘤大小、分化程度和血管侵犯无显著相关。Gal-3和5-LOX有协同作用,呈高度正相关(r=0.71,P<0.05)。Gal-3在胰腺癌组织和癌旁组织中蛋白阳性表达,分别为39例(84.1%)和8例(13.6%),两者比较差异具有统计学意义(P<0.05),且多为强阳性表达。5-LOX在胰腺癌组织和癌旁组织中的蛋白阳性表达,分别为37例(84.1%)和8例(18.2%),两者比较差异具有统计学意义(P<0.05),且多为阳性表达。结论:Gal-3和5-LOX在胰腺癌中表达增高,与病理分期和淋巴结转移有关,Gal-3和5-LOX表达呈正相关。
基金supported by the National Natural Science Foundation of China(No.82370592)the Discipline Construction Project of the Health System in Pudong New Area(No.PWZbr2022-15)the Pudong New Area Special Fund for Livelihood Research Project of Science and Technology Development Fund(No.PKJ2021-Y12),China.
文摘End-stage liver diseases,such as cirrhosis and liver cancer caused by hepatitis B,are often combined with hepatic encephalopathy(HE);ammonia poisoning is posited as one of its main pathogenesis mechanisms.Ammonia is closely related to autophagy,but the molecular mechanism of ammonia’s regulatory effect on autophagy in HE remains unclear.Sialylation is an essential form of glycosylation.In the nervous system,abnormal sialylation affects various physiological processes,such as neural development and synapse formation.ST3 β-galactoside α2,3-sialyltransferase 6(ST3GAL6)is one of the significant glycosyltransferases responsible for addingα2,3-linked sialic acid to substrates and generating glycan structures.We found that the expression of ST3GAL6 was upregulated in the brains of mice with HE and in astrocytes after ammonia induction,and the expression levels of α2,3-sialylated glycans and autophagy-related proteins microtubule-associated protein light chain 3(LC3)and Beclin-1 were upregulated in ammonia-induced astrocytes.These findings suggest that ST3GAL6 is related to autophagy in HE.Therefore,we aimed to determine the regulatory relationship between ST3GAL6 and autophagy.We found that silencing ST3GAL6 and blocking or degrading α2,3-sialylated glycans by way of Maackia amurensis lectin-II(MAL-II)and neuraminidase can inhibit autophagy.In addition,silencing the expression of ST3GAL6 can downregulate the expression of heat shock proteinβ8(HSPB8)and Bcl2-associated athanogene 3(BAG3).Notably,the overexpression of HSPB8 partially restored the reduced autophagy levels caused by silencing ST3GAL6 expression.Our results indicate that ST3GAL6 regulates autophagy through the HSPB8-BAG3 complex.
