Geranylgeranylacetone (GGA), an isoprenoid compound widely utilized as an antiulcer agent in Asia, confers protection against ischemia, anoxia, and oxidative stress by rapidly enhancing the expression of HSP70. Nevertheless, the impact of GGA on sepsis-associated intestinal injury remains unexplored. Thus, this study is crafted to elucidate the protective efficacy and underlying mechanisms of GGA against septic intestinal damage. Our findings revealed that GGA significantly extended the survival duration of septic mice, and mitigated lipopolysaccharide (LPS)-induced alterations in intestinal permeability and tissue damage. Furthermore, GGA effectively suppressed LPS-induced cytokine release, attenuated levels of reactive oxygen species (ROS) and malondialdehyde, and bolstered antioxidant-related parameters within the intestinal tissue of LPS-stimulated mice. Mechanistically, GGA significantly increased HSP70 expression and promoted E3 ubiquitin ligase CHIP to play the role in ubiquitination and degradation of karyopherin-α2 (KPNA2), resulting in inhibition of nuclear translocation of NF-κB and reduced NOX1, NOX2 and NOX4 expression. The inhibitory action of GGA on cytokine release and ROS generation was abolished by CHIP knockdown in IEC-6 cells treated with LPS. Simultaneously, the downregulation of CHIP reversed the suppressive role of GGA in the LPS-induced NF-κB activation and the expression of NOX1, NOX2 and NOX4 in IEC-6 cells. The effects of GGA on mitigating intestinal damage, inflammation and oxidative stress caused by LPS were eliminated in CHIP knockout mice. Our results demonstrate that the protective effect of GGA against LPS-caused intestinal injury of mice is dependent on CHIP activation, which promotes KPNA2 degradation and restrains translocation of NF-κB into nucleus, leading to suppressing LPS-induced inflammatory response and oxidative stress.

Sepsis is a severe inflammatory disorder that can lead to life-threatening multiple organ injury. Lipopolysaccharide (LPS)-induced inflammation is the leading cause of multiple organ failure in sepsis. This study aimed to explore the effect of a novel agent, 2-(4-hydroxy-3-methoxyphenyl)-benzothiazole (YL-109), on LPS-induced multiple organ injury and the molecular mechanisms underlying these processes. The results showed that YL-109 protected against LPS-induced high mortality, cardiac dysfunction, pulmonary and intestinal injury through inhibiting the proinflammatory response, NLRP3 expression and pyroptosis-associated indicators in mouse tissues. YL-109 suppressed LPS-initiated cytokine release, pyroptosis and pyroptosis-related protein expression in HL-1, IEC-6 and MLE-12 cells, which was consistent with the results of the in vivo experiments. Mechanistically, YL-109 reduces phosphorylated ERK (extracellular signal-regulated kinase) levels and NF-κB activation, which are achieved through upregulating CHIP (carboxy terminus of Hsc70-interacting protein) expression, thereby inhibiting c-Jun and c-Fos activation as well as NLRP3 expression. As an E3 ligase, CHIP overexpression obviously promoted the degradation of phosphorylated ERK and inhibited the expression of NF-κB-mediated NLRP3 in cells stimulated with LPS. The protective effects of YL-109 against cardiac, pulmonary and intestinal damage, inflammation and pyroptosis caused by LPS were eliminated in CHIP knockout mice. Our results not only reveal the protective effect and molecular mechanism of YL-109 against LPS-mediated organs damage but also provide additional insights into the effect of CHIP on negatively regulating pyroptosis and inflammatory pathways.

近几年临床上对骨肿瘤的治疗取得重要进展,许多新的治疗方法不断出现,迫切要求骨肿瘤的病理诊断规范化[1-4].不规范的病理标本处理和取材导致病理诊断不准确、不全面,从而影响了临床精准治疗和患者的预后评估[5-7].目前国内对骨肿瘤标本处理尚缺乏统一的规范,期望该项工作有助于骨肿瘤标本处理的规范化,更好地指导临床对骨肿瘤患者的治疗和提高疗效.

Cardiac dysfunction has been recognized as a major contributor to mortality in sepsis, which is closely associated with inflammatory reactions. The carboxy terminus of Hsc70-interacting protein (CHIP), a U-box E3 ubiquitin ligase, defends against cardiac injury caused by other factors, but its role in sepsis-induced cardiac dysfunction has yet to be determined. The present study was designed to investigate the effects of CHIP on cardiac dysfunction caused by sepsis and the molecular mechanisms underlying these processes. We discovered that the CHIP level decreased gradually in the heart at different time points after septic model construction. The decline in CHIP expression of lipopolysaccharide (LPS)-stimulated cardiomyocytes was related to c-Jun activation that inhibited the transcription of CHIP. Functional biology experiments indicated that CHIP bound directly to karyopherin-α 2 (KPNA2) and promoted its degradation through polyubiquitination in cardiomyocytes. CHIP overexpression in cardiomyocytes obviously inhibited LPS-initiated release of TNF-α and IL-6 by promoting KPNA2 degradation, reducing NF-κB translocation into the nucleus. Consistent with the in vitro results, data obtained from animal experiments indicated that septic transgenic mice with heart-specific CHIP overexpression showed a weaker proinflammatory response and reduced cardiac dysfunction than septic control mice. Furthermore, we found that the therapeutic effect of compound YL-109 on cardiac dysfunction in septic mice was due to the upregulation of myocardial CHIP expression. These findings demonstrated that sepsis-initiated the activation of c-Jun suppressed CHIP transcription. CHIP directly promoted ubiquitin-mediated degradation of KPNA2, which reduced the production of proinflammatory cytokines by inhibiting the translocation of NF-κB from the cytoplasm into the nucleus in myocardium, thereby attenuating sepsis-induced cardiac dysfunction.

全膝关节置换术(TKA)标本是病理科常见标本之一,由于缺少取材和诊断规范,TKA标本病理取材和诊断不规范的现象非常普通.病理诊断在指导临床和影像诊断、临床治疗及科研方面未发挥出应用价值.近几年,我们摸索TKA标本处理和诊断规范化流程,希望该项工作有助于取材和诊断的规范化.

Geranylgeranylacetone (GGA), an inducer of heat shock proteins, exerts anticancer activity in some tumours. However, the effect of GGA on human osteosarcoma (OS) has not been reported. This work is designed to evaluate the effect of GGA on the proliferation and apoptosis of human OS cells and to explore the underlying mechanisms. It was found that GGA markedly inhibited the proliferation and induced apoptosis of U-2 OS cells in a dose-dependent manner and also up-regulated the expression of heat shock protein 70 (Hsp70). The degradation and ubiquitination of protein arginine N-methyltransferase 1 (PRMT1) were obviously enhanced in U-2 OS cells with CHIP overexpression and GGA treatment. The expression of PRMT1 was reversed in GGA-treated cell after CHIP knockdown. The turnover of PRMT1 was obviously faster in cells overexpressing CHIP than that in control cells. The methylation and activity of STAT3 were induced by PRMT1, resulting in the inhibition of FAS transcription. Overexpression of PRMT1 reversed the effect of GGA on activation of apoptosis-related proteins and U-2 OS cell apoptosis. The expressions of PRMT1 were significantly up-regulated in OS tissues compared with the adjacent normal tissues and benign bone tumours. In conclusion, GGA promotes the degradation of PRMT1 through the Hsp70-CHIP-mediated proteasome pathway, thereby inducing the FAS-triggered cell apoptosis. Inhibition of PRMT1 may be a potential therapeutic strategy for OS patients.

The E6 protein of the human papillomavirus (HPV) underpins important protein interaction networks between the virus and host to promote viral infection. Through its interaction with E6AP, a host E3 ubiquitin (UB) ligase, E6 stirs the protein ubiquitination pathways toward the oncogenic transformation of the infected cells. For a systematic measurement of E6 reprogramming of the substrate pool of E6AP, we performed a proteomic screen based on "orthogonal UB transfer (OUT)" that allowed us to identify the ubiquitination targets of E6AP dependent on the E6 protein of HPV-16, a high-risk viral subtype for the development of cervical cancer. The OUT screen identified more than 200 potential substrates of the E6-E6AP pair based on the transfer of UB from E6AP to the substrate proteins. Among them, we verified that E6 would induce E6AP-catalyzed ubiquitination of importin proteins KPNA1-3, protein phosphatase PGAM5, and arginine methyltransferases CARM1 to trigger their degradation by the proteasome. We further found that E6 could significantly reduce the cellular level of KPNA1 that resulted in the suppression of nuclear transport of phosphorylated STAT1 and the inhibition of interferon-γ-induced apoptosis in cervical cancer cells. Overall, our work demonstrates OUT as a powerful proteomic platform to probe the interaction of E6 and host cells through protein ubiquitination and reveals a new role of E6 in down-regulating nuclear transport proteins to attenuate tumor-suppressive signaling.

Background: Karyopherin α2 (KPNA2), a member of the karyopherin α family, has been studied in several cancers but has not yet been substantially investigated in malignant bone tumors. The purpose of the current study was to evaluate the KPNA2 expression level and its utility as a novel diagnostic biomarker in osteosarcomas and malignant bone tumor mimics, such as chondrosarcomas and Ewing sarcomas (ESs).Method: We investigated the expression of KPNA2 protein by immunohistochemistry on paraffin-embedded surgical specimens from 223 patients with malignant and benign bone tumors, including 81 osteosarcomas, 42 chondrosarcomas, 15 ESs, 28 osteoid osteomas, 20 osteochondromas and 37 chondroblastomas. Immunoreactivity was scored semiquantitatively based on staining extent and intensity.Results: Sixty-seven of 81 (82.7%) osteosarcoma, zero of 42 (0%) chondrosarcoma and one of 15 (6.7%) ES samples showed immunoreactivity for KPNA2. Negative KPNA2 expression was observed in all benign bone tumors. The expression of KPNA2 in osteosarcoma samples was much higher than that in chondrosarcoma and ES samples (P<0.001). The sensitivity and specificity of KPNA2 immunoexpression for detecting osteosarcoma were 82.7% and 100%, respectively. Several subtypes of osteosarcoma were analyzed, and immunostaining of KPNA2 was frequent in osteoblastic samples (90.9%), with 39 samples (70.9%) showing strong-intensity staining. KPNA2 positivity was observed in ten of 13 (76.9%) chondroblastic, two of 6 (33.3%) fibroblastic, three of 4 (75%) telangiectatic and two of 3 (66.7%) giant cell-rich osteosarcoma samples. The strongest intensity staining was observed in osteoblastic osteosarcoma.Conclusion: KPNA2 is frequently expressed in osteosarcomas, particularly in osteoblastic and chondroblastic tumors, but is rarely positive in chondrosarcomas and ESs. This feature may aid in distinguishing between osteosarcoma and other bone sarcoma mimics. This report supports KPNA2 as a novel marker for the diagnosis of osteosarcoma.