Role of post-translational modification of basic leucine zipper transcription factors in response to abiotic stresses in plants / 生物工程学报

Abiotic stresses substantially affect the growth and development of plants. Plants have evolved multiple strategies to cope with the environmental stresses, among which transcription factors play an important role in regulating the tolerance to abiotic stresses. Basic leucine zipper transcription factors (bZIP) are one of the largest gene families. The stability and activity of bZIP transcription factors could be regulated by different post-translational modifications (PTMs) in response to various intracellular or extracellular stresses. This paper introduces the structural feature and classification of bZIP transcription factors, followed by summarizing the PTMs of bZIP transcription factors, such as phosphorylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification, in response to abiotic stresses. In addition, future perspectives were prospected, which may facilitate cultivating excellent stress-resistant crop varieties by regulating the PTMs of bZIP transcription factors.

Unveiling the clinical spectrum of relapsing polychondritis: insights into its pathogenesis, novel monogenic causes, and therapeutic strategies

Abstract Relapsing polychondritis is a rare multisystem disease involving cartilaginous and proteoglycan-rich structures. The diagnosis of this disease is mainly suggested by the presence of flares of inflammation of the cartilage, particularly in the ears, nose or respiratory tract, and more rarely, in the presence of other manifestations. The spectrum of clinical presentations may vary from intermittent episodes of painful and often disfiguring auricular and nasal chondritis to an occasional organ or even life-threatening manifestations such as lower airway collapse. There is a lack of awareness about this disease is mainly due to its rarity. In 2020, VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome, a novel autoinflammatory syndrome, was described. VEXAS syndrome is attributed to somatic mutations in methionine-41 of UBA1, the major E1 enzyme that initiates ubiquitylation. This new disease entity connects seemingly unrelated conditions: systemic inflammatory syndromes (relapsing chondritis, Sweet's syndrome, and neutrophilic dermatosis) and hematologic disorders (myelodysplastic syndrome or multiple myeloma). Therefore, this article reviews the current literature on both disease entities.

Effects of contusion and exhaustive exercise on murf1 and mafbx in the skeletal muscle of rats / Efectos de la contusión y del ejercicio exhaustivo sobre murf1 y mafbx en el músculo esquelético de ratas / Efeitos do trauma contuso e do exercício exaustivo no em murf1 e mafbx no músculo esquelético de ratos

ABSTRACT Objective To study the effects of contusion and exhaustive exercise on the expression of degradation-related factors MuRF1 and MAFbx in the skeletal muscle of rats and describe the repair mechanism of skeletal muscle injury. Methods Forty-two male SD rats were randomly divided into 7 groups. The rats in each group were killed at different time points (0h, 24h, 48h) after exhaustive exercise (E0, E24, E48) and contusion (D0, D24, D48), respectively, and in the resting state in control group (C). The right gastrocnemius muscles were resected and divided into two parts, one for the mRNAs of MuRF1 and MAFbx by real-time PCR, and the other for protein measurement by Western blotting. Results Compared with the control group, the MuRF1 mRNA and protein expression of the skeletal muscle in the E0 group was markedly increased (P <0.05) and followed by a downward trend in E24 the E48 groups. On the other hand, MuRF1 mRNA expression of the skeletal muscle in the D24 group was significantly upregulated (P <0.01), then decreased in the D48 group (P <0.01). Meanwhile, compared with the C group, MAFbx mRNA gene expression continued to be upregulated in D24 and D48 (P <0.05), but decreased in E24 and E48 (p<0.01). On the other hand, the NF-κB protein contents of the skeletal muscle in the D0, D24, and D48 groups, as well as in the E48 group, were markedly downregulated (P <0.05), and the one in E48 was also remarkably downregulated (P <0.05). Conclusion NF-κB may negatively regulate the process of protein degradation by the NF-κB / MuRF1 signal pathway. Level of evidence III; Therapeutic studies investigating the results of treatment.

RESUMEN Objetivo Estudiar los efectos de la contusión y del ejercicio exhaustivo sobre la expresión de los factores relacionados con la degradación MuRF1 y MAFbx en el músculo esquelético de ratas y describir el mecanismo de reparación de la lesión muscular esquelética. Métodos Cuarenta y dos ratas macho SD fueron divididas aleatoriamente en 7 grupos. Las ratas de cada grupo fueron sacrificadas en diferentes momentos (0h, 24h, 48h) después del ejercicio exhaustivo (E0, E24, E48) y de la contusión (D0, D24, D48), respectivamente, y en estado de reposo en el grupo de control (C). Se resecaron los músculos gastrocnemios derechos y se dividieron en dos partes, una para los ARNm de MuRF1 y MAFbx mediante PCR en tiempo real y la otra para la medición de proteínas mediante Western blot. Resultados En comparación con el grupo control, el ARNm de MuRF1 y la expresión proteica del músculo esquelético en el grupo E0 se incrementó notablemente (P <0,05) y fueron seguidos por una tendencia a la baja en los grupos E24 y E48. Por otra parte, la expresión del ARNm de MuRF1 del músculo esquelético en el grupo D24 fue significativamente regulada al alza (P <0,01), y luego disminuyó en el grupo D48 (P <0,01). Mientras tanto, en comparación con el grupo C, la expresión génica del ARNm de MAFbx permaneció regulada al alza en D24 y D48 (P <0,05), pero disminuyó en E24 y E48 (p<0,01). Por otro lado, el contenido de proteína NF-κB del músculo esquelético en los grupos D0, D24 y D48, así como en el grupo E48, se vio notablemente regulado a la baja (P <0,05), y el del grupo E48 también se vio notablemente regulado a la baja (P <0,05). Conclusión NF-κB puede regular negativamente el proceso de degradación de la proteína a través de la vía NF-κB / MuRF1. Nivel de evidencia III; Estudios terapéuticos que investigan los resultados del tratamiento.

RESUMO Objetivo Estudar os efeitos do trauma contuso e do exercício exaustivo na expressão dos fatores relacionados à degradação MuRF1 e MAFbx no músculo esquelético de ratos e descrever o mecanismo de reparo da lesão muscular esquelética. Métodos Quarenta e dois ratos SD machos foram divididos aleatoriamente em 7 grupos. Os ratos de cada grupo foram mortos em diferentes momentos (0h, 24h, 48h) após exercício exaustivo (E0, E24, E48) e trauma contuso (D0, D24, D48), respectivamente, e no estado de repouso no grupo controle (C). Os músculos gastrocnêmios direitos foram ressecados e divididos em duas partes, uma para os mRNAs de MuRF1 e MAFbx por PCR em tempo real e outra para a medição de proteínas a partir do Western blot. Resultados Em comparação com o grupo controle, o mRNA de MuRF1 e a expressão proteica do músculo esquelético no grupo E0 foram acentuadamente aumentados (P <0,05) e seguidos por uma tendência descendente nos grupos E24 e E48. Por outro lado, a expressão do mRNA de MuRF1 do músculo esquelético no grupo D24 foi significativamente regulada para cima (P <0,01), depois diminuiu no grupo D48 (P <0,01). Enquanto isso, em comparação com o grupo C, a expressão gênica do mRNA de MAFbx continuou regulada para cima em D24 e D48 (P <0,05), mas diminuiu em E24 e E48 (p<0,01). Por outro lado, os teores de proteína NF-κB do músculo esquelético nos grupos D0, D24 e D48, bem como no grupo E48, foram marcadamente regulados para baixo (P <0,05), e o do grupo E48 também foi notavelmente regulado para baixo (P <0,05). Conclusão NF-κB pode regular negativamente o processo de degradação da proteína pela via NF-κB / MuRF1. Nível de evidência III; Estudos terapêuticos que investigam os resultados do tratamento.

The Ubiquitin Ligase SMURF1 Catalyzes the Polyubiquitination of ADAR1 / 中国生物化学与分子生物学报

It is known that SMAD specific E3 ubiquitin protein ligase 1 (SMURF1) mediates autophagy through its E3 ubiquitin ligase activity, but the ubiquitinated substrates of SMURF1 need to be further explored. In this paper, the interacting proteins of SMURF1 in THP-1 cells were captured and identified by co-immunoprecipitation (Co-IP) combined with mass spectrometry. It was found that SMURF1 could physically bind to 222 proteins in THP-1 cells, and Adenosine deaminase acting on RNA 1 (ADAR1) had a higher peptide binding score. SMURF1 overexpression vectors were constructed and transfected into HEK-293T cells, then Co-IP and Western blotting assays verified the interaction between exogenous SMURF1 and endogenous ADAR1. qRT-PCR and Western blotting assays were carried out after transfecting SMURF1 overexpression vectors in HEK-293T cells, which identified that overexpression of SMURF1 attenuated the protein levels of ADAR1 (P<0. 05). However, there was no significant difference in the mRNA level of ADAR1. HEK-293T cells with normal and overexpressing SMURF1 were treated with cycloheximide (CHX), respectively, and Western blotting assays showed a shortened half-life of ADAR1 after overexpression of SMURF1 (P < 0. 05). Furthermore, overexpression of SMURF1 increased the polyubiquitination level of ADAR1 as detected by Co-IP and Western blot (P<0. 05). After the proteasome inhibitor (MG132) treatment, the Western blotting assay was performed to demonstrate that the negative regulatory effect of SMURF1 on ADAR1 was weakened after the proteasome degradation pathway was attenuated (P<0. 05). This study shows that SMURF1 interacts with ADAR1, catalyzes the polyubiquitination of ADAR1 and mediates its degradation through the proteasome pathway, which provides a theoretical basis for exploring the various biological functions of SMURF1 by affecting the stability of ADAR1.

The Deubiquitinating Enzyme USP14 Promotes the Proliferation and Migration Ability of Pancreatic Cancer Cells / 中国生物化学与分子生物学报

Pancreatic cancer remains one of the deadliest cancer types with few effective treatment options. While the overexpression of ubiquitin-specific protease 14 (USP14) has been observed in many tumor cells, including pancreatic cancer cells, its precise role in pancreatic cancer is not well defined. Here, we investigated the biological function of USP14 in pancreatic cancer and its molecular mechanisms. Our analysis of the Cancer Genome Atlas database revealed that USP14 was highly expressed in pancreatic cancer tissues,and further investigation revealed that its expression level was negatively correlated with the prognosis of patients. In SW1990 and MIAPaCa2 pancreatic cancer cells,we established stable USP14-knockdown cell lines using the shRNA-USP14 lentivirus and found that USP14 knockdown inhibited the proliferation and migration ability of pancreatic cancer cells by CCK8, colony formation assay, wound-healing and Transwell assays. Western blotting analysis showed that downregulation of USP14 expression resulted in a decrease in CyclinD3 protein levels, while overexpression of USP14 increased the protein levels in SW1990 and MIAPaCa2 pancreatic cancer cells. Furthermore, co-immunoprecipitation demonstrated that USP14 interacts with CyclinD3 and ubiquitination assays show that overexpression of USP14 reduces the ubiquitination level of CyclinD3. Moreover, CRISPR / Cas9-mediated USP14 knockout in SW1990 pancreatic cancer cells resulted in decreased CyclinD3 protein levels. These findings suggest that USP14 promotes the proliferation and migration ability of pancreatic cancer cells by interacting with CyclinD3, highlighting USP14 as a potential therapeutic target for pancreatic cancer.

The reversal effect of albiflorin on multidrug resistance of human ovarian cancer and its mechanism / 中国药理学通报

Aim To study the reversal effect of albiflorin(AL)on multidrug resistance of human ovarian cancer and the potential mechanism. Methods The drug resistance reversal effect of AL on SKOV3/DDP cells was detected by CCK-8 kit,and the effect of AL on P-glycoprotein(P-gp)function was detected by flow cytometry. The effects of AL on MYC,WWP1 and ABCB1 in SKOV3/DDP cells were detected by RT-qPCR and Western blot. The MYC-knockdown SKOV3/DDP cell line was constructed by RNA interference technology,and its drug resistance,P-gp function and related gene and protein expression changes were investigated. Results AL had a drug resistance reversal effect on SKOV3/DDP cells and a concentration-dependent inhibitory effect on P-gp function. The inhibitory effects of AL 25,50 and 100 μmol·L-1 on ABCB1/P-gp,MYC and WWP1 were gradually enhanced. The inhibitory effect of MYCi975,a MYC inhibitor,on ABCB1/P-gp,MYC and WWP1 was stronger than or equivalent to that of AL 100 μmol·L-1 group. After knockdown of MYC in SKOV3/DDP cells,cell drug resistance,P-gp function,and related gene and protein expression were inhibited. Conclusions The drug resistance reversal effect of AL on SKOV3/DDP cells may be related to the inhibition of P-gp function and the expression of ABCB1/P-gp,MYC and WWP1,which provides an experiment base for the development of AL as a drug resistance reversal agent for the clinical treatment of ovarian cancer.

Recent advances in role of E3 ubiquitin ligases in colorectal cancer / 中国药理学通报

Colorectal cancer (CRC) is one of the malignant tumors with the highest incidence and mortality in the world. The pathogenic mechanism of CRC has not been fully elucidated until now. Ubiquitination plays an important role in CRC development, and its effects mainly depend on E3 ubiquitin ligases, which could modify substrate proteins by ubiquitination, in turn altering their activity or mediating ubiquitin-proteasome degradation. Here research progress of the regulatory roles of RING (really interesting new gene) type and HECT(homologous to E6AP C-terminus) type E3 ubiquitin ligases in CRC cell proliferation, apoptosis, migration, invasion and chemotherapy sensitivity as well as targeted inhibitors of these E3 ligases are reviewed, providing new clues for the study of pathogenesis and targeted therapy of CRC.

The role of E3 ubiquitin ligases in bone homeostasis and related diseases

The ubiquitin-proteasome system (UPS) dedicates to degrade intracellular proteins to modulate demic homeostasis and functions of organisms. These enzymatic cascades mark and modifies target proteins diversly through covalently binding ubiquitin molecules. In the UPS, E3 ubiquitin ligases are the crucial constituents by the advantage of recognizing and presenting proteins to proteasomes for proteolysis. As the major regulators of protein homeostasis, E3 ligases are indispensable to proper cell manners in diverse systems, and they are well described in physiological bone growth and bone metabolism. Pathologically, classic bone-related diseases such as metabolic bone diseases, arthritis, bone neoplasms and bone metastasis of the tumor, etc., were also depicted in a UPS-dependent manner. Therefore, skeletal system is versatilely regulated by UPS and it is worthy to summarize the underlying mechanism. Furthermore, based on the current status of treatment, normal or pathological osteogenesis and tumorigenesis elaborated in this review highlight the clinical significance of UPS research. As a strategy possibly remedies the limitations of UPS treatment, emerging PROTAC was described comprehensively to illustrate its potential in clinical application. Altogether, the purpose of this review aims to provide more evidence for exploiting novel therapeutic strategies based on UPS for bone associated diseases.

Dioscin Inhibits Ubiquitin-Proteasome System in Cancer Cells / 肿瘤防治研究

Objective To explore the antitumor small molecules targeting the ubiquitin–proteasome system (UPS) on the basis of active molecules from traditional Chinese medicine. Methods UbG76V-GFP stably expressing cell line was constructed to screen novel small molecule inhibitors targeting UPS. The fluorogenic substrates of Suc-LLVY-AMC, Z-LLE-AMC, and Boc-LRR-AMC were used to assess the effect of dioscin on the 20S proteasome hydrolase activity. The Ub-AMC substrate was used to evaluate the effect of dioscin on the intracellular deubiquitinating enzyme activity. Western blot was used to detect the effect of dioscin on intracellular ubiquitination levels. CCK-8 and colony formation assays were used to detect the inhibitory effect of dioscin on the tumor cell proliferation. Results Dioscin is a UPS inhibitor discovered through the UbG76V-GFP reporter system. It enhances intracellular ubiquitination and inhibits tumor cell proliferation and colony formation by targeting deubiquitinating enzymes. Conclusion Dioscin could significantly inhibit tumor cell proliferation by targeting ubiquitin–proteasome.

Hydnocarpin inhibits malignant progression of triple negative breast cancer via CNOT4-mediated ubiquitination and degradation of YAP / 中国中药杂志

This study aims to investigate the effect and mechanism of hydnocarpin(HC) in treating triple negative breast cancer(TNBC). Cell counting kit-8(CCK-8), xCELLigence real-time cellular analysis(RTCA), and colony formation assay were employed to determine the effects of HC on the proliferation of two TNBC cell lines: MDA-MB-231 and MDA-MB-436. The effects of HC on the migration and invasion of TNBC cells were detected by high-content analysis, wound-healing assay, and Transwell assay. The changes in the epithelial-mesenchymal transition(EMT) and the expression of invasion-and migration-associated proteins [E-cadherin, vimentin, Snail, matrix metalloproteinase-2(MMP-2), and MMP-9] were detected by Western blot. Western blot and RT-qPCR were employed to determine the protein and mRNA levels of Yes-associated protein(YAP) and downstream targets(CTGF and Cyr61). TNBC cells were transfected with Flag-YAP for the overexpression of YAP, and the role of YAP as a key target for HC to inhibit TNBC malignant progression was examined by CCK-8 assay, Transwell assay, and wound-healing assay. The pathway of HC-induced YAP degradation was detected by the co-treatment of proteasome inhibitor with HC and ubiquitination assay. The binding of HC to YAP and the E3 ubiquitin ligase Ccr4-not transcription complex subunit 4(CNOT4) was detected by microscale thermophoresis(MST) assay and drug affinity responsive target stability(DARTS) assay. The results showed that HC significantly inhibited the proliferation, colony formation, invasion, and EMT of TNBC cells. HC down-regulated the protein and mRNA levels of CTGF and Cyr61. HC down-regulated the total protein level of YAP, while it had no effect on the mRNA level of YAP. The overexpression of YAP antagonized the inhibitory effects of HC on the proliferation, migration, and invasion of TNBC cells. HC promoted the degradation of YAP through the proteasome pathway and up-regulated the ubiquitination level of YAP. The results of MST and DARTS demonstrated direct binding between HC, YAP, and CNOT4. The above results indicated that HC inhibited the malignant progression of TNBC via CNOT4-mediated degradation and ubiquitination of YAP.

The dichotomous role of immunoproteasome in cancer: Friend or foe?

Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex (MHC)-I molecules. Apart from this primary function in antigen presentation, immunoproteasome is also responsible for the degradation of proteins, both unfolded proteins for the maintenance of protein homeostasis and tumor suppressor proteins contributing to tumor progression. The altered expression of immunoproteasome is frequently observed in cancers; however, its expression levels and effects vary among different cancer types exhibiting antagonistic roles in tumor development. This review focuses on the dichotomous role of immunoproteasome in different cancer types, as well as summarizes the current progression in immunoproteasome activators and inhibitors. Specifically targeting immunoproteasome may be a beneficial therapeutic intervention in cancer treatment and understanding the role of immunoproteasome in cancers will provide a significant therapeutic insight for the prevention and treatment of cancers.

Identification and study of regulatory axis that miRNA-224-5p targets NEDD4L gene in clear cell renal cell carcinoma / 肿瘤研究与临床

Objective:To screen key genes of renal clear cell carcinoma based on bioinformatics methods, identify possible microRNA (miRNA)-mRNA action axis, and explore the expression of related genes in clear cell renal cell carcinoma tissues and cells.Methods:Gene expression profiles of GSE40435 and GSE71302 datasets were obtained from the Gene Expression Omnibus (GEO) database. TCGA-KIRC datasets were obtained from The Cancer Genome Atlas (TCGA) database. R software was used to identify the differentially expressed mRNA and miRNA, and the functional enrichment analysis was performed. STRING database and Cytoscape software were used to perform the protein interaction analysis. The prognosis-related differentially expressed miRNA was evaluated by the Oncomir database. The potential targeted genes regulated by miRNA were determined by using TargetScan and miRDB targeted gene prediction tools. The tissue samples and clinicopathological features of 34 patients with clear cell renal cell carcinoma in the First Hospital of Shanxi Medical University from June to December 2021 were collected, and normal renal cell line 293T and clear cell renal cell carcinoma cell line 786O were selected. The real-time fluorescence quantitative polymerase chain reaction (qRT-PCR), was used to detect the relative expression of genes; Western blotting and immunohistochemical staining were used to detect the expression levels of the targeted proteins. The dual luciferase reporter gene assay was carried out to verify the targeting relationship between genes.Results:A total of 1 351 differentially expressed mRNA and 50 differentially expressed miRNA were screened and identified. The result of functional enrichment analysis suggested that the fatty acid metabolism pathway and xenobiotic metabolism pathway were suppressed in clear cell renal cell carcinoma, while the apoptosis and immune response pathways were activated. Protein interaction analysis suggested that the signal transduction and protein ubiquitination pathways might play a key role in clear cell renal cell carcinoma. The screening results showed that miRNA-224-5p (miR-224-5p) was most closely associated with clear cell renal cell carcinoma progression and was highly expressed in tumor tissues, and its prognosis-related target gene was NEDD4L. The relative expression of NEDD4L mRNA in clear cell renal cell carcinoma tissues and paraneoplastic tissues were 0.138±0.103 and 1.000±0.026 ( t = 46.23, P < 0.05), and the relative expression of miR-224-5p was 1.000±0.043 and 0.129±0.108 ( t = 45.28, P < 0.05). The differences of NEDD4L mRNA and miR-224-5p expressions in different grades and stages of clear cell renal cell carcinoma tissues were statistically significant (all P < 0.05). The expression of NEDD4L protein was decreased in clear cell renal cell carcinoma. The relative expression of NEDD4L gene in 293T and 786O cells were 1.000±0.125 and 0.210±0.044 ( t = 17.52, P < 0.05); the relative expressions of miR-224-5p gene were 0.209±0.049 and 1.000±0.234 ( t = 10.61, P < 0.05). The relative expressions of NEDD4L mRNA in miRNA mimic group and negative control group were 0.236±0.062 and 1.000±0.024, and the difference was statistically significant ( t = 43.56, P < 0.05). NEDD4L protein expression was reduced in the miRNA mimic group. Dual luciferase reporter gene assay suggested that NEDD4L was a direct target gene of miR-224-5p. Conclusions:In clear cell renal cell carcinoma, miR-224-5p targets and regulates NEDD4L expression, and this mechanism may be related to carcinogenesis and progression of clear cell renal cell carcinoma.

Research progress in the role of E3 ubiquitin ligases in viral infection / 中华微生物学和免疫学杂志

Ubiquitination modifications are a kind of post-translational modifications of proteins widely found in eukaryotes and involved in a variety of biological activities. E3 ubiquitin ligases are an important component of the ubiquitin system, with the function of specific recognition of substrate proteins and mediation of different types of ubiquitination modifications. They can regulate the function and life time of substrate proteins. Recent studies have shown that E3 ubiquitin ligases are widely involved in the regulation of the host innate immune response and can directly or indirectly influence viral infection. Moreover, viruses are able to encode or hijack E3 ubiquitin ligases in their long-term evolution, allowing them to play an important role in viral infection and replication cycle. This paper reviewed the progress in the mechanisms of E3 ubiquitin ligases in innate immune responses and viral infection in recent years.

Progress in the role of ubiquitin-proteasome system in hepatitis B virus X protein-mediated HBV infection and hepatocarcinogenesis / 中华微生物学和免疫学杂志

Chronic hepatitis B virus (HBV) infection is one of the leading causes of hepatocellular carcinoma (HCC). Ubiquitin-proteasome system (UPS) mediates the post-translational modification and degradation of protein in eukaryotic cells. Recent studies have revealed that UPS plays an important role in HBV infection and hepatocarcinogenesis. Targeting HBx to intervene in the progression of HBV infection or HBV-related HCC has become a research hotspot both domestically and internationally in recent years. This article reviewed the progress in HBx promoting HBV infection and hepatocarcinogenesis through UPS.

Relationship and associated mechanism of serum fibroblast growth factor 21 and sarcopenia in hemodialysis patients / 中华肾脏病杂志

Objective:To investigate the relationship between serum fibroblast growth factor 21 (FGF21) and sarcopenia in hemodialysis (HD) patients, and to explore the relationship between FGF21 and signal pathways related to skeletal muscle metabolism in uremic state at the cellular level.Methods:The data of the HD patients from the blood purification center of the Third Affiliated Hospital of Soochow University were collected in this prospective observational study between January 2018 and December 2019. Serum FGF21 concentration was detected by enzyme-linked immunosorbent assay (ELISA). Meanwhile, the skeletal muscle indexes (SMI) at the fourth thoracic vertebra (T4) and the first lumbar vertebra (L1) were assessed by chest CT. According to the T4 SMI and L1 SMI, the patients were divided into sarcopenia group and non-sarcopenia group. The relationship between serum FGF21 and sarcopenia was analyzed. The C2C12 mouse myoblasts were cultured in vitro, which were intervened with healthy human serum, healthy human serum+different concentrations of FGF21, uremic serum, uremic serum+different concentrations of FGF21. The expressions of muscle ring finger protein-1 (MURF1), muscle atrophy F-box (Atrogin-1), myogenic differentiation (MyoD) and myogenin (MyoG) were detected by Western blotting. Results:A total of 118 HD patients with age of (52.64±15.29) years were enrolled in the study, including 64 males (54.2%) and 54 females (45.8%). The images at T4 and L1 level assessed by chest CT could be acquired from 118 patients and 82 patients, respectively. According to the lowest sex-specific quartile ( P25) of T4 SMI (male < 59.92 cm 2/m 2, female < 46.75 cm 2/m 2) and the lowest sex-specific quartile ( P25) of L1 SMI (male < 29.02 cm 2/m 2, female < 24.50 cm 2/m 2), patients were divided into sarcopenia group and non-sarcopenia group, and there were 29(24.58%) and 20(24.39%) patients in the sarcopenia group, respectively. When the patients were divided into two groups according to the sex-specific lowest quartile of T4 SMI, although the serum FGF21 level in the sarcopenia group was higher than that in the non-sarcopenia group, there was no statistical significance between the two groups [448.52(183.96, 1 684.08) ng/L vs. 273.65 (152.83, 535.54) ng/L, Z=-1.741, P=0.082]. When the patients were divided into two groups according to the sex-specific lowest quartile of L1 SMI, the serum FGF21 level in the sarcopenia group was significantly higher than that in the non-sarcopenia group [460.95(188.91, 1 276.38) ng/L vs. 239.10(133.25, 466.36) ng/L, Z=-2.170, P=0.030]. Binary logistic regression analysis showed that higher serum FGF21 was an independent influencing factor for sarcopenia in HD patients regardless of whether the patients were divided into two groups according to the sex-specific lowest quartile of T4 SMI or the sex-specific lowest quartile of L1 SMI (T4 SMI grouping: OR=4.085, 95% CI 1.778-9.388, P=0.001; L1 SMI grouping: OR=7.327, 95% CI 1.841-29.160, P=0.005). At T4 and L1 levels, the area under the receiver operating characteristic curve of FGF21 in predicting sarcopenia in HD patients was 0.636(95% CI 0.494-0.779, P=0.036) and 0.684(95% CI 0.535-0.833, P=0.018), respectively. Cell experiment showed that compared with the uremic serum group, the expressions of MURF1 and Atrogin-1 in myotube cells were increased, while the expressions of MyoD and MyoG were significantly decreased in uremic serum+FGF21 group (both P < 0.05). Conclusions:Higher serum FGF21 is associated with an increased risk of sarcopenia in HD patients. FGF21 may increase the expression of ubiquitin proteasome system, reduce the synthesis and differentiation of skeletal muscle protein, and promote the occurrence of muscle atrophy in uremic patients

Role of PIAS-regulated SUMOylation of PPARγ in endogenous protective mechanism against endotoxin-induced acute lung injury in mice / 中华麻醉学杂志

Objective:To evaluate the role of small ubiquitin-associated modifier (SUMO) E3 ligase (PIAS)-regulated SUMOylation of peroxisome proliferator-activated receptor γ (PPARγ) in the endogenous protective mechanism against endotoxin-induced acute lung injury (ALI) in mice.Methods:Experiment Ⅰ Twenty-four clean-grade wild type male C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: control group (C group), ALI group, ALI+ PPARγ inducer TZD group (ALI+ T group) and ALI+ TZD+ SUMOylation inhibitor anacardic acid group (ALI+ T+ A group). Lipopolysaccharide (LPS) 15 mg/kg was injected into the tail vein to develop the ALI model. In ALI+ T+ A group, anacardic acid 5 mg/kg was intraperitoneally injected at 1 h before LPS administration. In ALI+ T group and ALI+ T+ A group, TZD 50 mg/kg was intraperitoneally injected at 30 min before LPS administration. The mice were sacrificed at 12 h after LPS administration, and the lung tissues were obtained to examine the pathological changes which were scored and to determine the wet/dry (W/D) weight ratio, and expression of PIAS1, PIAS2, PIAS3 and PIASy protein and mRNA (by Western blot or polymerase chain reaction). Experiment Ⅱ Mouse alveolar macrophages (MH-S cells) were cultured in vitro and divided into 4 groups ( n=5 each) using a random number table method: control group (C group), LPS group, LPS+ PIAS2 siRNA group (L+ P group) and LPS+ Con siRNA group (L+ C group). Cells were routinely cultured in group C. Cells were stimulated with 10 μg/ml LPS to develop the model of endotoxin challenge. PIAS2 siRNA 50 nmol/L and Con siRNA 50 nmol/L were transfected at 48 h before LPS was added in L+ P group and L+ C group, respectively. The cells were collected at 24 h of incubation with LPS to determine the cell viability, levels of M1 and M2 alveolar macrophages (by flow cytometry), expression of PIAS2 and PPARγ (by Western blot), co-expression of PPARγ-SUMO1 (by immunoprecipitation) and expression of tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10) mRNA (by polymerase chain reaction). The ratio of M1/M2 was calculated. Results:Experiment Ⅰ Compared with C group, the lung injury scores and W/D ratio were significantly increased, and the expression of PIAS2 protein and mRNA was up-regulated in the other three groups ( P<0.05). Compared with ALI group, the lung injury scores and W/D ratio were significantly decreased, and the expression of PIAS2 protein and mRNA was up-regulated in ALI+ T group and ALI+ T+ A group ( P<0.05). Compared with ALI+ T group, the lung injury scores and W/D ratio were significantly increased, and the expression of PIAS2 protein and mRNA was down-regulated in ALI+ T+ A group ( P<0.05). There was no significant difference in the expression of PIAS1, PIAS3 and PIASy protein and mRNA in lung tissues among the four groups ( P>0.05). Experiment Ⅱ Compared with C group, the cell viability was significantly decreased, the expression of PPARγ and co-expression of PPARγ-SUMO1 was up-regulated, the levels of M1 and M2 macrophages and M1/M2 ratio were increased, the expression of TNF-α mRNA was up-regulated, and the expression of IL-10 mRNA was down-regulated in the other three groups, and PIAS2 expression was significantly up-regulated in L group and L+ C group ( P<0.05). Compared with L group, the cell viability was significantly decreased, the expression of PIAS2 and PPARγ and PPARγ-SUMO1 co-expression were down-regulated, the M1 macrophage level and M1/M2 ratio were increased, TNF-α mRNA expression was up-regulated, and the expression of IL-10 mRNA was down-regulated in L+ P group ( P<0.05), and no significant change was found in the parameters mentioned above in L+ C group ( P>0.05). Compared with L+ C group, the cell viability was significantly decreased, the expression of PIAS2 and PPARγ and co-expression of PPARγ-SUMO1 were down-regulated, the level of M1 alveolar macrophages and M1/M2 ratio were increased, the expression of TNF-α mRNA was down-regulated, and the expression of IL-10 mRNA was up-regulated in L+ P group ( P<0.05). Conclusions:PIAS2-regulated SUMOylation of PPARγ is the endogenous protective mechanism against endotoxin-induced ALI in mice, which may be related to inhibition of macrophage polarization into M1 type and alleviation of inflammatory responses.

Effect of selective cerebral mild hypothermia on SUMO2/3 modification of Drp1 in a rat model of cerebral ischemia-reperfusion / 中华麻醉学杂志

Objective:To evaluate the effect of selective cerebral mild hypothermia on small ubiquitin-like modifier 2/3 (SUMO2/3) modification of dynamin-related protein 1 (Drp1) in a rat model of cerebral ischemia-reperfusion (I/R).Methods:Sixty clean-grade healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 240-260 g, were divided into 4 groups ( n=15 each) using a random number table method: sham operation group (S group), cerebral I/R group (I/R group), selective cerebral mild hypothermia group (HT group) and normal temperature group (NT group). The operation was performed under the monitoring of cerebral temperature and rectal temperature.Only the cervical blood vessels were exposed in S group, while focal cerebral I/R was induced by 2 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion in anesthetized animals in the other three groups.In HT group and NT group, 4 and 37 ℃ normal saline was perfused through the left internal carotid artery at a rate of 80 ml·kg -1·h -1 for 15 min, respectively. Modified neurological severity score (mNSS) was assessed at 24 h of reperfusion. Then the rats were sacrificed under deep anesthesia, brains were removed, brain tissues were obtained for determination of the percentage of cerebral infarct size (by TTC staining), and the ischemic penumbra tissues in the cerebral cortex were removed for examination of the ultra-structural changes of mitochondria (with a transmission electron microscope) and for determination of the SUMO2/3 modification of Drp1 (by CO-IP), expression of total Drp1 (T-Drp1) and total cytochrome c (T-Cytc) (by Western blot), and expression of mitochondrial outer membrane Drp1 (M-Drp1) and cytoplasmic Cytc (C-Cytc) (by Western blot) after isolation of mitochondria and cytoplasm. Results:Compared with S group, the mNSS and percentage of cerebral infarct size were significantly increased, the expression of M-Drp1, T-Drp1, C-Cytc and T-Cytc was up-regulated, and SUMO2/3 modification of Drp1 in ischemic penumbra area was increased ( P<0.05), the fragmentation of mitochondria was aggravated, and cristae rupture and vacuolation were obvious in the other three groups. Compared with I/R group, the mNSS and percentage of cerebral infarct size were significantly decreased, the expression of M-Drp1, T-Drp1, C-Cytc and T-Cytc was down-regulated, SUMO2/3 modification of Drp1 was increased ( P<0.05), the fragmentation of mitochondria was significantly attenuated, and cristae rupture and vacuolation were weakened in HT group. There were no significant differences in these detection parameters between NT group and I/R group ( P>0.05). Conclusions:The mechanism by which selective cerebral mild hypothermia alleviates the cerebral I/R injury is related to increased SUMO2/3 modification of Drp1, decreased binding of Drp1 to mitochondrial outer membrane, and reduced mitochondrial excessive fission in rats.

Study on the inhibitory effect of UBE2T on radiosensitivity of lung adenocarcinoma / 中华放射肿瘤学杂志

Objective:To investigate the effect of ubiquitin binding enzyme 2T (UBE2T) on the radiosensitivity of lung adenocarcinoma and unravel its possible mechanism.Methods:A total of 45 patients pathologically diagnosed with different stages of lung adenocarcinoma and treated with radiotherapy in the Second Affiliated Hospital of Zunyi Medical University from March, 2019 to December, 2021 were enrolled, and the efficacy was evaluated according to response evaluation criteria in solid tumors (RECIST1.1). All patients were divided into radiosensitive group ( n=25) and radioresistant group ( n=20). Radiosensitive group was complete remission (CR)+partial remission (PR), and radioresistant group was stable disease (SD) + progression disease (PD). Immunohistochemistry (IHC) was used to calculate the score based on the staining intensity and the number of positive cells. Chi-square test was combined to analyze the correlation between the expression level of UBE2T in paraffin specimens of lung adenocarcinoma patients and the radiosensitivity of patients. Lentivirus UBE2T-interfered (UBE2Tsh) A549 and UBE2T-overexpressed SPC-A-1 lung adenocarcinoma cells and their respective controls were constructed for irradiation and colony formation assay. The survivor fraction curve was fitted by single-hit multi-target model. The DNA double-strand break (DSB) marker γH2AX foci were detected by immunofluorescence (IF). The expression levels of UBE2T, γH 2AX and Rad51 proteins were detected by Western blot. Cell cycle and apoptosis rate of A549 were determined by flow cytometry. Binary variables were statistically analyzed by Fisher's exact probability method and measurement data were assessed by t-test. Results:High-expression level of UBE2T was correlated with the radiosensitivity of lung adenocarcinoma patients ( P<0.05). UBE2Tsh improved the radiosensitivity of A549 lung adenocarcinoma cells, and the sensitizing enhancement ratio (SER) was 1.795. UBE2T overexpression decreased the radiosensitivity of SPC-A-1 lung adenocarcinoma cells with an SER of 0.293. γH2AX foci number per cell were significantly increased in UBE2Tsh A549 cells after irradiation ( P<0.01) . Compared with the control group, the expression level of γH2AX protein was up-regulated ( P<0.01)and that of Rad51 protein was down-regulated in UBE2Tsh A549 cells after radiation ( P<0.001). Compared with the control group, the expression level of γH2AX protein was down-regulated ( P<0.05) and that of Rad51 protein was up-regulated in UBE2T overexpressed SPC-A-1 cells ( P<0.001). The proportion of UBE2Tsh A549 cells in G 2 phase was decreased ( P<0.01) and cell apoptosis was increased ( P<0.001). Conclusions:UBE2T might promote the radioresistance of lung adenocarcinoma cells by enhancing DNA DSB repair induced by radiotherapy, inducing cell cycle G 2 phase arrest, and reducing cell apoptosis.

Research progress of tripartite motif-containing protein 28 in tumors / 中国医师杂志

Tripartite motif-containing protein 28 is a kind of macromolecular protein with E3 ubiquitin ligase, which belongs to an important member of the TRIM protein family. As a new molecular biomarker, it has attracted wide attention. TRIM28 is highly expressed in many kinds of malignant tumors, which is closely related to clinicopathological features, and is also involved in biological behaviors such as proliferation, apoptosis, migration and invasion of tumor cells. TRIM28 may be a potential marker and therapeutic target for clinical diagnosis and prognosis of tumors. This study reviews the structure and biological function of TRIM28, its relationship with malignant tumors and the molecular mechanism of signal transduction pathway.

Elevated phosphorylated ubiquitin level elicits neuro-degeneration by aggregating the decline of ubiquitin-dependent proteasomal degradation / 中国药理学与毒理学杂志

OBJECTIVE To determine the roles of phosphorylated ubiquitin(pUb)on ubiquitin-dependent proteasomal(UPS)degradation activity,and the roles of pUb on neurodegeneration.METHODS We use PTEN induced kinase 1(PINK1)to phosphorylate ubiquitin.The Ub/S65A cannot be phosphorylated by PINK1,and was used to antagonize the roles of pUb.The Ub/S65E was used to mimic the roles of pUb.The roles of pUb on UPS degradation activity were determined by immunoflu-orescence,Western blot and TIRF microscope at cellular and protein level.The roles of pUb on neurodegeneration were determined by behavior tests,immunofluorescence,Golgi staining,TEM,Western blot and proteomics sacle in mouse.RESULTS The level of soluble PINK1(sPINK1)and pUb increased in the neurons of aged mouse brain,and in the cells upon the administration of MG132,a proteasome inhibitor.The elevation of sPINK1 and pUb was accompanied by protein aggregation upon aging or the proteasomal inhibition.The pink1 knockout alleviated proteasomal inhibition induced protein aggregation and association of ubiquitinated proteins with proteasome.The over-expression of sPINK1 increased pUb level in hippocampal neuron,which chronically induced protein aggregation,mitochondrial damage and damage the structure of neuronal spines.Such neuronal injury lead to cognitive impairment of mice.The roles of sPINK1 was reversed by co-expression with Ub/S65A,and was mimic by over-expression with Ub/S65E.CONCLUSION The phosphorylation of ubiquitin aggravates UPS degrada-tion,and accelerates neuronal degeneration upon the decline of proteasomal degradation in aging and age-related neuronal diseases.