1
|
Yang FW, Fu Y, Li Y, He YH, Mu MY, Liu QC, Long J, Lin SD. Prostaglandin E1 protects hepatocytes against endoplasmic reticulum stress-induced apoptosis via protein kinase A-dependent induction of glucose-regulated protein 78 expression. World J Gastroenterol 2017; 23:7253-7264. [PMID: 29142472 PMCID: PMC5677201 DOI: 10.3748/wjg.v23.i40.7253] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/24/2017] [Accepted: 08/25/2017] [Indexed: 02/07/2023] Open
Abstract
AIM To investigate the protective effect of prostaglandin E1 (PGE1) against endoplasmic reticulum (ER) stress-induced hepatocyte apoptosis, and to explore its underlying mechanisms.
METHODS Thapsigargin (TG) was used to induce ER stress in the human hepatic cell line L02 and hepatocarcinoma-derived cell line HepG2. To evaluate the effects of PGE1 on TG-induced apoptosis, PGE1 was used an hour prior to TG treatment. Activation of unfolded protein response signaling pathways were detected by western blotting and quantitative real-time RT-PCR. Apoptotic index and cell viability of L02 cells and HepG2 cells were determined with flow cytometry and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay.
RESULTS Pretreatment with 1 μmol/L PGE1 protected against TG-induced apoptosis in both L02 cells and HepG2 cells. PGE1 enhanced the TG-induced expression of C/EBP homologous protein (CHOP), glucose-regulated protein (GRP) 78 and spliced X box-binding protein 1 at 6 h. However, it attenuated their expressions after 24 h. PGE1 alone induced protein and mRNA expressions of GRP78; PGE1 also induced protein expression of DNA damage-inducible gene 34 and inhibited the expressions of phospho-PKR-like ER kinase, phospho-eukaryotic initiation factor 2α and CHOP. Treatment with protein kinase A (PKA)-inhibitor H89 or KT5720 blocked PGE1-induced up-regulation of GRP78. Further, the cytoprotective effect of PGE1 on hepatocytes was not observed after blockade of GRP78 expression by H89 or small interfering RNA specifically targeted against human GRP78.
CONCLUSION Our study demonstrates that PGE1 protects against ER stress-induced hepatocyte apoptosis via PKA pathway-dependent induction of GRP78 expression.
Collapse
Affiliation(s)
- Fang-Wan Yang
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Yu Fu
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
- Department of Infectious Diseases, Heze Municipal Hospital, Heze 274000, Shandong Province, China
| | - Ying Li
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Yi-Huai He
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Mao-Yuan Mu
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Qi-Chuan Liu
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Jun Long
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| | - Shi-De Lin
- Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical College, Zunyi 563003, Guizhou Province, China
| |
Collapse
|
2
|
Hara Y, Akamatsu Y, Maida K, Kashiwadate T, Kobayashi Y, Ohuchi N, Satomi S. A new liver graft preparation method for uncontrolled non-heart-beating donors, combining short oxygenated warm perfusion and prostaglandin E1. J Surg Res 2013; 184:1134-42. [PMID: 23688794 DOI: 10.1016/j.jss.2013.04.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 03/17/2013] [Accepted: 04/17/2013] [Indexed: 01/03/2023]
Abstract
BACKGROUND To resolve the shortage of donors associated with liver transplantation, the potential uncontrolled non-heart-beating donor (UNHBD) pool is expected to increase. However, warm ischemia-reperfusion injury leads to inferior survival in transplantation using the grafts from UNHBD compared with those from heart-beating donors. To overcome this problem, we developed a new method for preparation of liver grafts from UNHBDs consisting of a combination of short oxygenated warm perfusion (SOWP) and prostaglandin E1 (PGE1). METHODS Using an ex vivo perfusion rat model, we examined the effectiveness of this new method. RESULTS Using SOWP and PGE1 treatment, the total amount of bile production during reperfusion in UNHBD grafts was increased to the same level as that in the heart-beating donor grafts. The addition of PGE1 to SOWP buffer decreased aspartate aminotransferase/alanine aminotransferase and tumor necrosis factor α levels during 1 h of reperfusion. Necrosis and apoptosis were significantly decreased by SOWP + PGE1 treatment. SOWP + PGE1 ameliorated induction of mitochondrial permeability transition, and the total amount of mitochondrial cytochrome c in the SOWP + PGE1 group after reperfusion was kept significantly higher than that in the no treatment group. Cytosolic c-Jun N-terminal protein kinase activation was significantly suppressed by SOWP + PGE1. Decrease in mitochondrial Bcl-2 was suppressed by SOWP alone and SOWP + PGE1 treatment, and Bax in the mitochondria was significantly suppressed by SOWP + PGE1. CONCLUSION SOWP and PGE1 prior to cold preservation significantly improved the function of liver grafts that underwent warm ischemia-reperfusion injury. Therefore, this method might be useful in liver transplantation using UNHBD grafts.
Collapse
Affiliation(s)
- Yasuyuki Hara
- Division of Advanced Surgical Science and Technology, Graduate School of Medicine, Tohoku University, Sendai, Japan.
| | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
Linoleic and alpha-linolenic acids are the fatty acids designated as "essential" since they are not synthesized by mammalian cells and must be provided in the diet. The recent dietary shift towards the consumption of n-6 (omega-6) at the expense of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) is thought to be a primary cause of many diseases related to the Western diet. The body converts linoleic acid to arachidonic acid and derives eicosapentaenoic acid from alpha-linolenic acid. Ideally the effects of these fatty acids and their eicosanoid derivatives are tailored to the specific biological needs of the body. The balance between n-3 and n-6 PUFAs is essential for metabolism and maintenance of the functions of both classes. The availability of n-3 long chain PUFAs plays a major role in regulating both fat accumulation and its elimination by the liver. Derangement of hepatic n-6:n-3 PUFA ratio impacts on the histological pattern of fatty liver through modulation of the amount of intrahepatic lipids. Moreover, the influence of PUFAs and their eicosanoid products on hepatic microcirculation and ischemia/reperfusion injury has been demonstrated in many studies. This concise review article will focus on the role of PUFAs and eicosanoids in hepatic steatosis, microcirculation and ischemia/reperfusion injury.
Collapse
Affiliation(s)
- Ashraf Mohammad El-Badry
- Swiss HPB (Hepato-Pancreatico-Biliary) Centre, Department of Visceral and Transplant Surgery, University Hospital Zurich, Ramistrasse 100, CH-8091, Zurich, Switzerland
| | | | | |
Collapse
|
4
|
Dołegowska B, Pikuła E, Safranow K, Olszewska M, Jakubowska K, Chlubek D, Gutowski P. Metabolism of eicosanoids and their action on renal function during ischaemia and reperfusion: the effect of alprostadil. Prostaglandins Leukot Essent Fatty Acids 2006; 75:403-11. [PMID: 17011760 DOI: 10.1016/j.plefa.2006.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 07/16/2006] [Indexed: 11/28/2022]
Abstract
Eicosanoids, active metabolites of arachidonic acid (AA), play an important role in the regulation of renal haemodynamics and glomerular filtration. Our study verified the hypothesis on the positive action of exogenously administered PGE(1) on renal function during an operation with temporary ischaemia of the lower half of the body. Also the effect of alprostadil (prostaglandin E(1) analogue) administered during the operation of an abdominal aorta aneurysm on the postoperative systemic metabolism of AA and the glomerular filtration rate (GFR) was investigated. The study included 42 patients with a diagnosed abdominal aorta aneurysm who have been qualified for the operation of implantation of the aortic prosthesis. The patients were randomly assigned to two groups: the study group (I) receiving alprostadil and the control group (II) without alprostadil. The levels of hydroxyeicosatetraenoic acids (15-HETE, 12-HETE, 5-HETE) were determined by RP-HPLC and the level of thromboxane B(2) (TxB(2)) was determined by ELISA in the plasma of the blood drawn from vena cava superior immediately before aortic clamping (A) and 5 min after aortic declamping (B). The administration of PGE(1) affects the metabolism of 15-HETE in a manner dependent on the baseline value of GFR but does not significantly change the postoperative renal function. The metabolism of 15-HETE is affected by the baseline value of GFR1 and a longer period of ischaemia is correlated with lower concentrations of 5-HETE during reperfusion. The results of our studies indicate that TxB(2) influences the postoperative function of kidneys.
Collapse
Affiliation(s)
- B Dołegowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Al. Powstancow Wlkp. 72, 70-111 Szzecin, Poland.
| | | | | | | | | | | | | |
Collapse
|
5
|
Pérez LM, Milkiewicz P, Elias E, Coleman R, Sánchez Pozzi EJ, Roma MG. Oxidative Stress Induces Internalization of the Bile Salt Export Pump, Bsep, and Bile Salt Secretory Failure in Isolated Rat Hepatocyte Couplets: A Role for Protein Kinase C and Prevention by Protein Kinase A. Toxicol Sci 2006; 91:150-8. [PMID: 16452108 DOI: 10.1093/toxsci/kfj113] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have shown that Ca2+-mediated protein kinase C (PKC) activation induces impairment of bile salt secretory function and F-actin redistribution in hepatocyte couplets. Because oxidative stress induces Ca2+ elevation, we tested here whether PKC inhibition or protein kinase A (PKA) activation, which often counteracts PKC-dependent effects, can prevent and reverse these alterations. The pro-oxidant compounds tert-butylhydroperoxide (tBOOH, 100 microM) and 2,3-dimethoxy-1,4-naphthoquinone (30 microM), reduced by -41% and -29%, respectively, the percentage of couplets accumulating the fluorescent bile salt analog, cholyl-lysylfluorescein in their canalicular vacuoles (p < 0.01). tBOOH-induced bile salt secretory failure was accompanied by internalization of the canalicular bile salt export pump (Bsep), and disarrangement of cytoskeletal F-actin. All these deleterious effects were fully prevented by the intracellular Ca2+ chelator BAPTA/AM (20 microM), the pan-specific PKC inhibitors H7 (100 microM) and staurosporine (1 microM), the inhibitor of Ca2+-dependent PKCs, Gö6976 (2 microM), and the PKA activator dibutyryl-cAMP (500 microM). H7, Gö6976, and dibutyryl-cAMP not only prevented but also fully reversed the decrease in the cholyl-lysyl-fluorescein accumulation. In conclusion, these results suggest that low levels of oxidative stress impair bile salt secretion by internalizing Bsep through a Ca2+-dependent, PKC-mediated mechanism, and that inhibition of PKC, or activation of PKA, prevents and reverses these effects. Alterations in actin organization may be a causal factor.
Collapse
Affiliation(s)
- Leonardo M Pérez
- Institute of Experimental Physiology, CONICET-National University of Rosario, Rosario, Argentina
| | | | | | | | | | | |
Collapse
|
6
|
Weber H, Hühns S, Lüthen F, Jonas L, Schuff-Werner P. Calpain activation contributes to oxidative stress-induced pancreatic acinar cell injury. Biochem Pharmacol 2005; 70:1241-52. [PMID: 16154113 DOI: 10.1016/j.bcp.2005.06.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/17/2005] [Accepted: 06/20/2005] [Indexed: 01/25/2023]
Abstract
Oxygen radicals have been implicated as mediators in the pathogenesis of pancreatic acinar cell necrosis. However, the sequence of events between the oxidative insult and cell damage remains unclear. In the current study, we investigated whether the Ca(2+)-regulated cytosolic cysteine protease calpain is activated by oxidative stress and contributes to oxidant-induced acinar cell damage. Isolated rat pancreatic acinar cells were exposed to hydrogen peroxide (H(2)O(2))-generated oxidative stress in the presence or absence of the Ca(2+) chelator 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA-AM) and different calpain inhibitors including benzyloxycarbonyl-valyl-phenylalanine methyl ester. Calpain activation was studied by fluorescence spectrophotometry and immunoblotting. Cell injury was assessed by lactate dehydrogenase (LDH) release and characterization of the cellular ultrastructure including fluorescence-labeled actin filaments. Exposure of acinar cells to H(2)O(2) provoked a time- and dose-dependent increase in calpain proteolytic activity involving the ubiquitous isoforms mu- and m-calpain. The activation of calpain reflected the time course of developing cytotoxicity as demonstrated by increased LDH release. Inhibition of oxidant-induced calpain activity by BAPTA-AM and various calpain inhibitors provoked a decline in oxidant-induced cell injury. In particular, changes in the actin filament organization characterized by an increase in the basolateral actin and by a detachment of actin from the cell membrane in the region of membrane blebs were clearly reduced. In summary, our findings suggest that acinar cell damage through oxidative stress requires activation of calpain and that the actin cytoskeleton belongs to the cellular targets of the protease. The results support the hypothesis that calpain activation may play a role in the development of acute pancreatitis.
Collapse
Affiliation(s)
- H Weber
- Institute of Clinical Chemistry and Laboratory Medicine, University of Rostock, Germany.
| | | | | | | | | |
Collapse
|
7
|
Takahashi HK, Iwagaki H, Tamura R, Katsuno G, Xue D, Sugita S, Mori S, Yoshino T, Tanaka N, Nishibori M. Differential effect of prostaglandins E1 and E2 on lipopolysaccharide-induced adhesion molecule expression on human monocytes. Eur J Pharmacol 2005; 512:223-30. [PMID: 15840408 DOI: 10.1016/j.ejphar.2005.01.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 01/20/2005] [Accepted: 01/27/2005] [Indexed: 10/25/2022]
Abstract
The effect of prostaglandins E1 and E2 on the 1 ng/ml lipopolysaccharide-induced expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes was examined. Prostaglandin E1 suppressed B7.1 and CD40 expression, but prostaglandin E2 did not effect on any type of adhesion molecule expression. Both prostaglandins inhibited tumor necrosis factor (TNF)-alpha production and T-cell proliferation of lipopolysaccharide-treated human peripheral blood mononuclear cells (PBMC). Among prostaglandin E1 receptors (IP/EP1/EP2/EP3/EP4) agonists, ONO-1301, a prostanoid IP-receptor agonist, prevented B7.1 and CD40 expression. ONO-AE1-259-01 a prostanoid EP2-receptor agonist, ONO-AE1-329, a prostanoid EP4-receptor agonist, and ONO-1301 inhibited TNF-alpha production and T-cell proliferation. Moreover, anti-B7.1 and anti-CD40 Abs prevented lipopolysaccharide-induced TNF-alpha production and T-cell proliferation. Therefore, the effect of prostaglandin E1 on TNF-alpha production and T-cell proliferation might depend on the inhibition of B7.1 and CD40 expression, but that of prostaglandin E2 might be independent of adhesion molecules expression. In conclusion, the mechanism responsible for the effect of prostaglandin E1 on lipopolysaccharide-induced responses is distinct from that of prostaglandin E2.
Collapse
Affiliation(s)
- Hideo K Takahashi
- Department of Pharmacology, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Morioka D, Kubota T, Sekido H, Matsuo K, Saito S, Ichikawa Y, Endo I, Togo S, Shimada H. Prostaglandin E1 improved the function of transplanted fatty liver in a rat reduced-size-liver transplantation model under conditions of permissible cold preservation. Liver Transpl 2003; 9:79-86. [PMID: 12514777 DOI: 10.1053/jlts.2003.36845] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this study was to determine whether the minimum necessary volume of a moderate fatty liver graft was similar to the normal liver volume and to elucidate means for improving the function of the transplanted fatty liver if it were inferior in volume to a normal liver under conditions of permissible cold preservation. Nine-week-old male Wistar rats were used. Normal rat chow was fed to the normal liver group, and fat-enriched rat chow was fed to the fatty liver group for 4 weeks to induce a moderately fatty liver. Liver transplantation with various volumes of reduced-size grafts, including whole liver graft (100%LT), 70% volume graft (70%LT), and 30% volume graft (30%LT), was performed with both groups of rats as donors. All procedures were performed under the conditions of 2-hour cold preservation. All rats with an implanted normal liver were surviving at 7 days after the operation regardless of the graft volume (100%LT, 5 of 5; 70%LT, 5 of 5; 30%LT, 5/5). In contrast, the survival rates decreased according to the graft volume in rats implanted with fatty livers (100%LT, 8 of 8; 70%LT, 5 of 8; 30%LT, 2/8). To improve the survival of 30%LT with fatty liver, we employed two potent inhibitors of ischemia-reperfusion injury: FK506 and prostaglandin E1. Though FK506 had no advantageous effect, prostaglandin E1 significantly improved the survival rate and diminished serum levels of alanine aminotransferase and hyaluronic acid. In conclusion, the volume of graft necessary for successful transplantation is larger in fatty livers than in normal livers in permissible cold preservation. Also, prostaglandin E1 protects grafts against ischemia-reperfusion injury and improves the functioning of a transplanted fatty liver.
Collapse
Affiliation(s)
- Daisuke Morioka
- Second Department of Surgery, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Sato M, Ohkohchi N, Tsukamoto S, Koyamada N, Asakura T, Enomoto Y, Usuda M, Miyagi S, Okada A, Satomi S. Successful liver transplantation from agonal non-heart-beating donors in pigs. Transpl Int 2002. [PMID: 12595971 DOI: 10.1111/j.1432-2277.2003.tb00270.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An effective way to overcome shortage of donors in liver transplantation (LTx) is to consider such from non-heart-beating donors (NHBDs). We investigated how a liver graft should be treated before and/or after procurement for successful LTx from an NHBD. Porcine LTx was performed with FR167653 (FR), a dual inhibitor of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), and/or prostaglandin E(1) (PG). Animals were allocated to an FR group (n=4, donors and recipients were treated with FR), a PG group (n=4, donors and recipients were treated with PG), or an FRPG group (n=4, donors and recipients were treated with both FR and PG). No recipients in the FR group and only two of four recipients in the PG group survived, whereas all recipients in the FRPG group survived. Suppression of TNF-alpha and IL-1beta and maintenance of microcirculation are the key to successful transplantation from NHBDs.
Collapse
Affiliation(s)
- Masahide Sato
- Division of Advanced Surgical Science and Technology, Graduate School of Medicine, Tohoku University, 1-1 Seiryo-machi, Aobaku, Sendai, 980-8574 Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Sato M, Ohkohchi N, Tsukamoto S, Orii T, Koyamada N, Asakura T, Takayama J, Enomoto Y, Goto M, Usuda M, Miyagi S, Okada A, Satomi S. New strategy for liver transplantation from non-heart-beating donors. Transplant Proc 2002; 34:2608-9. [PMID: 12431542 DOI: 10.1016/s0041-1345(02)03443-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- M Sato
- Division of Advanced Surgical Science and Technology, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Ohkohchi N. Mechanisms of preservation and ischemic/reperfusion injury in liver transplantation. Transplant Proc 2002; 34:2670-3. [PMID: 12431569 DOI: 10.1016/s0041-1345(02)03370-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- N Ohkohchi
- Department of Surgery, Institute of Clinical Medicine, Tsukuba University, Tsukuba, Japan
| |
Collapse
|
12
|
Marceau N, Loranger A, Gilbert S, Daigle N, Champetier S. Keratin-mediated resistance to stress and apoptosis in simple epithelial cells in relation to health and disease. Biochem Cell Biol 2002. [PMID: 11716296 DOI: 10.1139/o01-138] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Epithelial cells such as hepatocytes exhibit highly polarized properties as a result of the asymmetric distribution of subsets of receptors at unique portions of the surface membrane. While the proper targeting of these surface receptors and maintenance of the resulting polarity depend on microtubules (MTs), the Golgi sorting compartment, and different actin-filament networks, the contribution of keratin intermediate filaments (IFs) has been unclear. Recent data show that the latter cytoskeletal network plays a predominant role in providing resistance to various forms of stress and to apoptosis targeted to the surface membrane. In this context, we first summarize our knowledge of the domain- or assembly-related features of IF proteins and the dynamic properties of IF networks that may explain how the same keratin pair K8/K18 can exert multiple resistance-related functions in simple epithelial cells. We then examine the contribution of linker protein(s) that integrate interactions of keratin IFs with MTs and the actin-cytoskeleton network, polarity-dependent surface receptors and cytoplasmic organelles. We next address likely molecular mechanisms by which K8/K18 can selectively provide resistance to a mechanical or toxic stress, or to Fas-mediated apoptosis. Finally, these issues on keratin structure-function are examined within a context of pathological anomalies emerging in tissue architecture as a result of natural or targeted mutations, or posttranslational modifications at specific amino acid residues. Clearly. the data accumulated in recent years provide new and significant insights on the role of K8/K18, particularly under conditions where polarized cells resist to stressful or apoptotic insults.
Collapse
Affiliation(s)
- N Marceau
- Centre de recherche en cancérologie et Departement de médecine, Université Laval, Quebec, QC, Canada.
| | | | | | | | | |
Collapse
|
13
|
Abstract
Oxidative stress in mammalian cells is an inevitable consequence of their aerobic metabolism. The production of reactive oxygen and nitric oxide species causes oxidative modifications of proteins often combined with a loss of their biological function. Like most partially denatured proteins, moderately oxidized proteins are more sensitive to proteolytic attack by proteases. The diverse cellular proteolytic systems are an important secondary defense against oxidative stress by degrading oxidized and damaged proteins, thereby preventing their intracellular accumulation. In mammalian cells, a range of proteases exists which are distributed throughout the cell. In this review we summarize the function of the cytosolic (proteasome and calpains), the lysosomal, the mitochondrial and the nuclear proteolytic pathways in response to oxidative stress. Particular emphasis is given to the proteasomal system, since this pathway appears to be the most important proteolytic system involved in the removal of oxidatively modified or damaged proteins.
Collapse
Affiliation(s)
- Jana Mehlhase
- Neuroscience Research Center, Medical Faculty (Charité) of the Humboldt University Berlin, Germany
| | | |
Collapse
|
14
|
Akamatsu K, Yamasaki Y, Nishikawa M, Takakura Y, Hashida M. Synthesis and pharmacological activity of a novel water-soluble hepatocyte-specific polymeric prodrug of prostaglandin E(1) using lactosylated poly(L-glutamic hydrazide) as a carrier. Biochem Pharmacol 2001; 62:1531-6. [PMID: 11728389 DOI: 10.1016/s0006-2952(01)00799-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A novel polymeric prodrug of prostaglandin E(1) (PGE(1)) was synthesized using lactosylated poly(L-glutamic hydrazide) (Lac-NH-PLGA) as a targetable carrier to hepatocytes. Poly(L-glutamic hydrazide) (PLGA-HZ) was prepared by reacting poly(gamma-benzyl-L-glutamate) with hydrazine monohydrate, followed by coupling with lactose via a hydrazone linkage. Then the lactosylated PLGA-HZ was reduced by sodium cyanoborohydride (NaBH(3)CN) in order to make the linkage irreversible (Lac-NH-PLGA). Finally, PGE(1) was bound to hydrazide moieties remaining in Lac-NH-PLGA without any condensing agent under weakly acidic conditions (pH 5) where PGE(1) would be chemically most stable at room temperature (PGE(1) conjugate). The PGE(1) conjugate prepared was sufficiently water-soluble in spite of the hydrophobic nature of its backbone (-NH-CH-CO-) and PGE(1) itself. After intravenous injection in mice, the [111In]PGE(1) conjugate rapidly accumulated in the liver, whereas [111In]PLGA-HZ did not, suggesting the involvement of a galactose-specific mechanism in the uptake of the [111In]PGE(1) conjugate. Fractionation of liver cells revealed that the [111In]PGE(1) conjugate was preferentially taken up by liver parenchymal cells. The pharmacological activity was examined in mice with fulminant hepatitis induced by intraperitoneal injection of carbon tetrachloride. Intravenous injection of the PGE(1) conjugate at a dose of 1 mg (0.065 mg PGE(1))/kg effectively inhibited the increase in plasma glutamic pyruvic transaminase (GPT) activity compared with that of free PGE(1) at a dose of 0.065 or 0.65 mg/kg. These results suggest that the PGE(1) conjugate is an excellent prodrug for the treatment of fulminant hepatitis.
Collapse
Affiliation(s)
- K Akamatsu
- Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, 606-8501, Kyoto, Japan
| | | | | | | | | |
Collapse
|