Objective To observe the degradation regulation of ubiquitinproteasome inhibitor nuclear factor kappa;B（NF-kappa;B）and its inhibitory signal protein Ikappa;B kinase in earlier period diabetic retinopathy（DR）,and the effects on retinal ganglion cells (RGC) apoptosis.Methods Forty healthy adult Wistar rats were randomly divided into control (group A）,DR（group B）,DR+lowconcentration MG132 treated （group C）and DR+high concentration MG132 treated（group D）groups,10 rats in each group.After 6 and 8 weeks,the results of body masses and fasting blood glucose (FBG) were detected,the expression of NF-kappa;B and Ikappa;B were observed by immunohistochemistry respectively.RGC apoptosis was assessed by the terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labelling (TUNEL) method.Results The expression of NF-kappa;B was upregulated in group B compared with group A,its expression decreased in group D compared with group B; but the expression of Ikappa;B was contrary to NF-kappa;B; RGC apoptosis was followed a similar pattern with the expression of NF-kappa;B; the differences among them were statistically significant (P＜0.01).Compared the expression of NF-kappa;B，Ikappa;B and RGC apoptosis in group C and D, there were no statistically significant differences(P＞0.05).Conclusion Ubiquitin-proteasome inhibitor MG132 can block the activation of NF-kappa;B,inhibit ubiquitination of Ikappa;B degradation and RGC apoptosis.
Objective To study the quantitative changes of ubiquitin l igase MAFbx mRNA and protein expression, muscle atrophy and muscle function following free muscle transplantation and to explore relationshi ps among them. Methods Thirty-six female SD rats, SPF grade, weighing (250 ± 25) g, were used. One hind l imb of the rat was randomly selected as experimental side to receive in situ free gracil is muscle transplantation, and the counterlateral hind l imb underwent no operation serving as control side. General condition of the rats was observed after operation. Muscle contractivecapacity and muscle wet weight maintenance rate of the experimental and the control side were detected 1, 2, 4, 10, 15, and 30 weeks after operation, and 6 rats were killed at each time point. Meanwhile, HE staining was performed to observe muscle fibre cross-sectional area, real-time quantitative PCR was appl ied to detect relative expression of MAFbx/Atrogin-1 mRNA, and Western blot test was used to observe MAFbx protein expression. Results All rats survived till the end of the experiment, all incisions healed well, and no dysfunction occurred in the experimental sides. The value of muscle contractive capacity, muscle wet weight maintenance rate, muscle’s maximal force of single contraction, and muscle’s maximal force of tetanic contraction in the experimental sides dramatically decreased in the first 4 weeks after operation and increased gradually over 4 to 30 weeks. The MAFbx mRNA expression of the experimental sides peaked and was seven times greater than the control sides 2 weeks after operation, then the value gradually decreased over 15 to 30 weeks after operation and was 1.1 to 1.5 times greater than the control sides, and significant difference was evident between the experimental sides and the control sides at each time point (P lt; 0.05). Significant difference was evident between the experimental sides and the control sides in terms of MAFbx protein expression of the muscle 1 to 15 weeks after operation according to the Western blot result (P lt; 0.05), and no significant difference was noted at 30 weeks (P gt; 0.05). The correlation coefficient between muscle wet weight maintenance rate and muscle’s maximal force of single contraction maintenance rate was 0.95, between muscle wet weight maintenance rate and muscle’s maximal force of tetanic contraction maintenance rate was 0.75, between muscle fibre cross-sectional area recovery rate and muscle’s maximal force of single contraction maintenance rate was 0.93, and between muscle fibre cross-sectional area recovery rate and muscle’s maximal force of tetanic contraction maintenance rate was 0.68 (P lt; 0.05). The correlation coefficient between MAFbx mRNA expression and the parameter of muscle wet weight maintenance rate, muscle fibre cross-sectional area recovery rate, muscle’s maximal force of single contraction maintenance rate, and muscle’s maximal force of tetanic contraction maintenance rate was — 0.62 (P lt; 0.05), — 0.45 (P gt; 0.05), — 0.72 (P lt; 0.05) and — 0.78 (P lt; 0.05), respectively; the correlation coefficient between MAFbx protein relative expression and the parameter of muscle wet weight maintenance rate, muscle fibre cross-sectional area recovery rate, muscle’s maximal force of single contraction maintenance rate, and muscle’s maximal force of tetanic contraction maintenance rate was — 0.95 (P lt; 0.05), — 0.82 (P lt; 0.05), — 0.89 (P lt; 0.05), and — 0.54 (P gt; 0.05), respectively. Conclusion Decrease of muscle function after transplantation correlates closely with muscle atrophy. The high expression of MAFbx mRNA and protein, especially their persistent increases from 4 to 15 weeks after nerve reinnervation, is a junction between the muscle atrophy and thedecrease of muscle function.
Objective To study the role of ubiquitin-proteasome pathway in diaphragm of COPD rats. Mathods Thirty rats were divided into a normal control group and a COPD group. COPD model was established by exposure to cigarette smoke for three months. The protein levels of E2-14k and proteasome subunit C8 in diaphragms were measured by Western blot. The mRNA levels of ubiquitin and proteasome subunit C2 in diaphragms were measured bymeans of realtime polymerase chain reaction( RT-PCR) . Results Compared with the control group, the protein expression of E2-14k increased significantly in the COPD group ( 0. 81 ±0. 28 vs 0. 50 ±0. 25, P lt;0. 05) , but C8 protein level was not significantly different between the two groups( P gt;0. 05) . The mRNA expression of ubiquitin increased significantly in the COPD group( 0. 89 ±0. 20 vs 0. 50 ±0. 15, P lt;0. 05) , but C2 mRNA level was not significantly different between the two groups ( P gt; 0. 05 ) . Conclusions The mRNA and protein expressions of ubiquitin-proteasome pathway in diaphragmincreased significantly in COPD rats, suggesting that the activity of ubiquitin-proteasome pathwayincreased, which lead to an increase of protein degradation.
ObjectiveTo investigate the expression of ubiquitin-specific protease 9X (USP9X) in pancreatic cancer, and to evaluate the correlation of USP9X with the survival of patients with pancreatic cancer. MethodThe expression of USP9X was detected in 55 pieces of surgically resected primary pancreatic cancer tissues and adjacent nontumorous pancreatic tissues by streptavidin-perosidase immunohistochemical method. ResultsThe rate of USP9X high expression in the 55 pieces of the primary pancreatic cancer tissues was 58.2% (32/55), which in the adjacent nontumorous pancreatic tissues was zero. The expression of USP9X was not correlated with the gender, age, tumor position, or tumor size (P > 0.05), while which was significantly correlated with the differentiation degree, lymph node metastasis, or TNM stage (P < 0.05). By using Cox proportional hazard model, the multivariable analysis revealed that the differentiation degree, lymph node metastasis, and USP9X expression were the independent risk factors. Survival of the patient with USP9X high expression was significantly shorter than that with USP9X low expression (P < 0.05), and there was the same result in the patients with stageⅡ, with lymph node negative, or intermediate differentiation degree (P < 0.05). ConclusionThe results indicate that USP9X might play an important role in the pathogenesis and prognosis of pancreatic cancer.
ObjectiveTo explore the effects of silencing the expression of ubiquitin-conjugating enzyme E2T (UBE2T) gene on proliferation, apoptosis, migration and invasion abilities of A549 cells.MethodsA549 cells were cultured in vitro. Three sets of shRNA-UBE2T plasmid vectors (UBE2T-shRNA1 group, UBE2T-shRNA2 group, UBE2T-shRNA3 group) and shRNA-NC (shRNA-NC group) were constructed, respectively. A549 cells were transfected with lipofection transfection. The cells transfected with empty vector were enrolled as control (control group). The transfection efficiency was detected by RT-PCR. The effects of silencing the expression of UBE2T gene on biological behaviors (proliferation, apoptosis, migration, and invasion) of lung cancer A549 cells were detected by clone formation assay, flow cytometry, Transwell assay and scratch test. The expression of proliferation and apoptosis related proteins, and expression of PI3K/AKT signaling pathway proteins were detected by Western blot. ResultsAfter transfection, expression level of UBE2T mRNA in UBE2T-shRNA1 group, UBE2T-shRNA2 group and UBE2T-shRNA3 group was significantly down-regulated (all P<0.05), whose down-regulation was the most significant in UBE2T-shRNA3 group (P<0.05). Compared with control group and shRNA-NC group, clone formation rate, number of invasion A549 cells, scratch healing rate, Ki67 expression, PCNA expression, p-PI3K/PI3K ratio and p-AKT/AKT ratio were significantly decreased in UBE2T-shRNA3 group (P<0.05), while A549 apoptosis rate, Bax/Bcl-2 ratio and cleaved caspase-3/caspase-3 ratio were significantly increased (P<0.05). There were no significant differences in the above indexes between control group and shRNA-NC group (P>0.05). ConclusionsThe shRNA interfering with UBE2T is reliable to construct the model of A549 cells with stable low-expression UBE2T. Down-regulation of UBE2T expression can promote apoptosis of A549 cells, inhibit their proliferation, invasion and migration abilities. The mechanism may be related to inhibiting the activation of PI3K/AKT signaling pathway.
Objective To investigate the expressions of ubiquitin-proteasome markers，including E2-14K，MAFbx，MuRF-1，and nuclear factor-κB（NF- κB） p50，in diaphragm of COPD rats，and their relationship with IL-17 level in diaphragm and serum in order to elucidate the potential mechanism of diaphragm atrophy. Methods Thirty healthy adult male SD rats were randomly divided into a model group （n=18） and a normal control group （n=12）. The COPD rat model was established by instillation of lipopolysaccharide （LPS） and exposure to cigarette smoke for 28 days. The protein levels of E2-14K，MAFbx，MuRF-1，and NF-κB p50 in diaphragm were measured by Western blot. The concentration of IL-17 in serum and diaphragm was measured by ELISA. Results Western blot showed that the protein expressions of E2-14K，MAFbx，MuRF-1，and NF-κB p50 in diaphragm increased significantly in the COPD model group compared with the normal control group （0.96±0.12 vs. 0.53±0.09，0.99±0.10 vs. 0.53±0.08，0.95±0.08 vs. 0.51±0.16，1.11±0.10 vs. 0.64±0.50，respectively，Plt;0.01）. The IL-17 level in serum and diaphragm was significantly higher in the COPD group than the control group. The expression of NF-κB p50 was positively correlated with E2-14K，MAFbx，and MuRF-1 expressions （r=0.82，0.92，0.86，respectively，Plt;0.01）. Both in serum and diaphragm，IL-17 level was positively correlated with the percentage of neutrophils，levels of NF-κB p50，E2-14K，MAFbx，and MuRF-1 expressions（all Plt;0.01）. The IL-17 levels in serum and diaphragm were also positively correlated each other （r=0.84，Plt;0.01）. Conclusions The results show that the ubiquitin-proteasom pathway，the NF-κB pathway and IL-17 are up-regulated in diaphragm of COPD rats .These alterations may contribute to diaphragm atrophy in COPD.
Valosin-containing protein is a membrane-bound protein that is highly conserved and widely existed in cells. Valosin-containing protein and it’s cofactors jointly participate in various cell functions such as protein degradation, gene replication, and cell cycle regulation, which maintain cellular homeostasis. Valosin-containing protein also exists in tumor cells, and its expression is closely related to the occurrence and development of tumors, but the specific mechanism needs to be further clarified. The application of valosin-containing protein inhibitors in tumor treatment has been continuously and in-depth researched. This article will explore several aspects of the molecular basis of valosin-containing protein, valosin-containing protein and cell homeostasis, tumors, and targeted therapy with valosin-containing protein. It aims to provide a certain basis for the clinical application of valosin-containing protein inhibitors.
Objective To study the effect of tumor necrosis factor-α( TNF-α) onhypermetabolism of skeletal muscle protein in rats with chronic obstructive pulmonary disease ( COPD) and explore its underlying mechanism. Methods Forty-five SD rats were randomly divided into a normal control group, a COPD group and a COPD + TNF-α group, with 15 rats in each group. COPD model was established by passive cigarette smoking in COPD group and COPD + TNF-αgroup. Then the extensor digitorium longus muscles ( EDL) were dissected and incubated in vitro muscle incubation system with adequate oxygen supply. The EDL were either cultured with or without recombinant rat TNF-α( 10 μg/L) . The mRNA and protein expressions of proteasome subunit C2 in EDL were quantified by real-time quantitative PCR and Western blot analysis, respectively. Results The mRNA and protein expressions of proteasome subunit C2 were both significant higher in the COPD group and COPD + TNF-αgroup than those in the normal control group( P lt;0. 01 or 0. 05) . The COPD+TNF-αgroup had higher expression of proteasome subunit C2 mRNA than that in the COPD group( P lt; 0. 01) , whereas the protein expression was not significantly different( P gt; 0. 05) . Conclusion Incresed proteolytic metabolism in skeletal muscle in COPD might be regulated by TNF-αactivated ubiquitin-dependent pathway.
Objective To investigate the influence of proteasome inhibitorMG-132 on inflammatory factors in COPD rats and its potential mechanism. Methods The COPD rat model was established by instillation of lipopolysaccharide and exposure to cigarette smoke. Then the rats were randomly divided into 4 groups( n = 12 in each group) , ie. a COPD model group, a COPD + MG-132 low concentration group ( 0. 05 mg·kg- 1·d - 1 ) , a COPD + MG-132 high concentration group( 0. 1 mg· kg- 1 · d - 1 ) , and a normal control group. The rats were injected intraperitoneally with different dose of MG-132 or normal saline. After 1 week and 4 weeks, 6 rats in each group were sarcrificed. Then the following parameters were determined including histopathological changes of lung tissue, and the concentrations of IL-1β, IL-6, IL-8 in serum and diaphragm via ELISA. Results The lung histopathological examination showed obvious emphysema and inflammatory infiltration in the COPD rats. These pathological changes were obviously ameliorated in two MG-132 treatment groups. The IL-1β, IL-6, and IL-8 levels in serumand diaphragmin the COPD model group were all significantly increased from1 week and 4 week than those in the normal control group( P lt;0. 05) .MG-132 down-regulated the expression of these inflammatory factors in a time-and dosedependent manner. The IL-1β, IL-6, and IL-8 levels in serum and diaphragm in the MG-132 low concentration group and high concentration group were all decreased compared with the COPD model group ( P lt; 0. 05) . Conclusion COPD is a systemic inflammatory disease which can be inhibited by the proteasome inhibitor MG-132 through suppressing inflammatory factors.
Sepsis is a multiple organ dysfunction syndrome caused by a dysregulated host response to infection. The mortality rate remains high under current treatment methods, and there is an urgent need to explore new therapeutic targets. Ubiquitination modification, as a key posttranslational regulation mechanism of proteins, plays a central role in the occurrence and development of sepsis and multiple organ damage by regulating key pathological processes such as inflammatory response, cell death and barrier function. This article aims to systematically elucidate the molecular mechanism of ubiquitination modification system in sepsis related organ damage, summarize the latest research progress on treatment strategies targeting the ubiquitination pathway, and explore the challenges and future transformation directions faced in this field. Through comprehensive analysis of existing research, this review aims to provide new ideas and theoretical basis for precise treatment of sepsis.