Age effects on liver inflammation and injury

年龄对肝脏炎症和损伤的影响

• 批准号: 8707913
• 负责人: Alex B. Lentsch
• 金额: $ 29.88万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8707913
• 关键词: 26S proteasome; Adult; Age; Age-Months; Binding; Biochemical; Cell Death; Cells; Childhood; Clinical; Clinical Research; Complication; Data; Defect; Event; Excision; Funding; Gene Expression; Hepatocyte; Incidence; Individual; Inflammatory Response; Injury; Ischemia; Kupffer Cells; Lead; Liver; Liver Dysfunction; Liver Failure; Modeling; Molecular Chaperones; Morbidity - disease rate; Multiple Organ Failure; Mus; NF-kappa B; Nature; Organ Transplantation; Organ failure; Pathogenesis; Patients; Phosphorylation; Population; Process; Protein Subunits; Proteins; Reperfusion Injury; Reperfusion Therapy; Resistance; Role; Stress; Testing; Tissues; Transfection; Transplantation; Trauma; Vascular Diseases; Work; acute liver injury; age effect; age related; base; cell type; cytokine; graft function; in vivo; inhibitor/antagonist; liver inflammation; liver injury; liver ischemia; mortality; multicatalytic endopeptidase complex; particle; public health relevance; response to injury; restoration; therapeutic development; therapeutic target; valosin-containing protein

DESCRIPTION (provided by applicant): Hepatic ischemia/reperfusion (I/R) injury is a primary cause of liver dysfunction in both pediatric and adult patients. During the previous funding period, using an established model of murine hepatic I/R, we found that old mice (12-13 months of age) have significantly greater liver injury after I/R than do young mice (4-6 weeks of age). These findings are consistent with clinical studies of trauma patients which suggest that pediatric patients have a far lower incidence of multiple organ dysfunction syndrome than do adult patients. We discovered that the increased injury was associated with decreased activation of the transcription factor, NF- kB, in hepatocytes of old mice. Our previous work suggests that NF-kB has divergent functions that are dependent upon the cell type involved. For example, activation of NF-kB in Kupffer cells appears to drive the inflammatory response, while NF-kB activation in hepatocytes appears to function in a cell-protective mechanism. Our more recent studies have begun to explore the mechanism by which NF-kB activation is different in young and old mice. We have found a major defect in the processing of the cytoplasmic inhibitor of NF-kB, IkBa, in old mice. First, we have shown that gene expression of specific subunits of the 19S regulatory particle of the 26S proteasome are significantly reduced in old mice. These protein subunits are involved in recruitment of ubiquitinylated substrates to the proteasome for degradation. Our studies suggest that decreased expression of these subunits reduce the degradation of IkBa and therefore decrease NF-kB activation in the livers of old mice. Secondly, we have preliminary data suggesting that a mode of recruitment of ubiquitinlylated IkBa to the proteasome is altered in old mice. The cytoplasmic chaperone, valosin- containing protein (VCP), is known to bind to ubiquitinylated proteins, including IkBa, and facilitate their recruitment to the proteasome. Phosphorylation of VCP by Akt regulates VCP's association with ubiquitinylated proteins. Our preliminary data demonstrate a defect in Akt activation in the livers of old mice. As such, the global hypothesis of this project is that age-dependent alterations to components of the proteasome and to substrate recruitment mechanisms in hepatocytes of old mice results in decreased activation of NF-kB which renders them more susceptible to ischemic stress than hepatocytes from young mice, resulting in increased oxidative tissue injury and cell death. We will test this hypothesis with three specific aims. Aim 1 will determine the mechanism by which age alters the chaperone function of VCP. Aim 2 will determine the specific roles of individual subunits of the 19S regulatory particle on substrate recruitment and degradation by the 26S proteasome. Finally, Aim 3 will determine whether in vivo protein transfection of 19S subunits and/or constitutively active Akt restores normal activation of NF-kB and reduces liver injury induced by I/R in old mice. These studies may identify therapeutic targets that could help lead to new treatments for acute liver injury resulting from a number of different clinical events including trauma, surgery, transplantation, vascular disease, etc.

描述（由申请人提供）：肝缺血/再灌注（I/R）损伤是儿童和成人患者肝功能障碍的主要原因。在之前的资助期间，使用已建立的小鼠肝脏I/R模型，我们发现老年小鼠（12-13月龄）在I/R后的肝损伤明显大于年轻小鼠（4-6周龄）。这些发现与创伤患者的临床研究一致，这些研究表明儿童患者多器官功能障碍综合征的发生率远低于成人患者。我们发现，损伤的增加与老年小鼠肝细胞中转录因子 NF-kB 的激活减少有关。我们之前的工作表明 NF-kB 具有不同的功能，这些功能取决于所涉及的细胞类型。例如，库普弗细胞中 NF-kB 的激活似乎会驱动炎症反应，而肝细胞中 NF-kB 的激活似乎在细胞保护机制中发挥作用。我们最近的研究已经开始探索年轻和年老小鼠中 NF-kB 激活不同的机制。我们发现老年小鼠体内 NF-kB 细胞质抑制剂 IkBa 的加工存在重大缺陷。首先，我们发现在老年小鼠中，26S蛋白酶体的19S调节颗粒的特定亚基的基因表达显着降低。这些蛋白质亚基参与将泛素化底物招募到蛋白酶体进行降解。我们的研究表明，这些亚基表达的减少会减少 IkBa 的降解，从而减少老年小鼠肝脏中 NF-kB 的激活。其次，我们的初步数据表明，在老年小鼠中，泛素化 IkBa 招募到蛋白酶体的模式发生了改变。细胞质伴侣，含缬洛辛蛋白 (VCP)，已知可与泛素化蛋白（包括 IkBa）结合，并促进它们招募至蛋白酶体。 Akt 对 VCP 的磷酸化调节 VCP 与泛素化蛋白的关联。我们的初步数据表明，老年小鼠肝脏中的 Akt 激活存在缺陷。因此，该项目的总体假设是，年老小鼠肝细胞中蛋白酶体成分和底物招募机制的年龄依赖性改变导致 NF-kB 激活减少，这使得它们比年轻小鼠的肝细胞更容易受到缺血应激的影响，从而导致氧化组织损伤和细胞死亡增加。我们将通过三个具体目标来检验这一假设。目标 1 将确定年龄改变 VCP 伴侣功能的机制。目标 2 将确定 19S 调节颗粒的各个亚基对 26S 蛋白酶体的底物招募和降解的具体作用。最后，目标 3 将确定 19S 亚基和/或组成型活性 Akt 的体内蛋白转染是否可以恢复 NF-kB 的正常激活并减少老年小鼠 I/R 引起的肝损伤。这些研究可能会确定治疗靶点，从而有助于开发出针对多种不同临床事件（包括创伤、手术、移植、血管疾病等）引起的急性肝损伤的新疗法。

项目成果

Ceramide mediates lung fibrosis in cystic fibrosis.

• DOI: 10.1016/j.bbrc.2013.03.032
• 发表时间: 2013-05-17
• 期刊: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
• 影响因子: 3.1
• 作者: Ziobro, Regan;Henry, Brian;Edwards, Michael J.;Lentsch, Alex B.;Gulbins, Erich
• 通讯作者: Gulbins, Erich

CXC chemokines play a critical role in liver injury, recovery, and regeneration.

• DOI: 10.1016/j.amjsurg.2009.01.025
• 发表时间: 2009-09
• 期刊: AMERICAN JOURNAL OF SURGERY
• 影响因子: 3
• 作者: Clarke, Callisia N.;Kuboki, Satoshi;Tevar, Amit;Lentsch, Alex B.;Edwards, Michael
• 通讯作者: Edwards, Michael

Inhibition of neutrophil exocytosis ameliorates acute lung injury in rats.

• DOI: 10.1097/shk.0b013e318282c9a1
• 发表时间: 2013-03
• 期刊: Shock (Augusta, Ga.)
• 作者: Uriarte SM;Rane MJ;Merchant ML;Jin S;Lentsch AB;Ward RA;McLeish KR
• 通讯作者: McLeish KR

A novel mouse model of depletion of stellate cells clarifies their role in ischemia/reperfusion- and endotoxin-induced acute liver injury.

• DOI: 10.1016/j.jhep.2013.09.013
• 发表时间: 2014-02
• 期刊: JOURNAL OF HEPATOLOGY
• 影响因子: 25.7
• 作者: Stewart, Rachel K.;Dangi, Anil;Huang, Chao;Murase, Noriko;Kimura, Shoko;Stolz, Donna B.;Wilson, Gregory C.;Lentsch, Alex B.;Gandhi, Chandrashekhar R.
• 通讯作者: Gandhi, Chandrashekhar R.