Metabolic dysfunction-associated steatotic liver disease (MASLD), the most prevalent chronic liver condition globally, lacks adequate and effective therapeutic remedies in clinical practice. Recent studies have increasingly highlighted the close connection between the ubiquitin-proteasome system (UPS) and the progression of MASLD. This relationship is crucial for understanding the disease's underlying mechanism. As a sophisticated process, the UPS govern protein stability and function, maintaining protein homeostasis, thus influencing a multitude of elements and biological events of eukaryotic cells. It comprises four enzyme families, namely, ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), ubiquitin-protein ligases (E3), and deubiquitinating enzymes (DUBs). This review aims to delve into the array of pathways and therapeutic targets implicated in the ubiquitination within the pathogenesis of MASLD. Therefore, this review unveils the role of ubiquitination in MASLD while spotlighting potential therapeutic targets within the context of this disease.

DNMT3A encodes a DNA methyltransferase involved in development, cell differentiation, and gene transcription, which is mutated and aberrant-expressed in cancers. Here, we revealed that loss of DNMT3A promotes malignant phenotypes in lung cancer. Based on the epigenetic inhibitor library synthetic lethal screening, we found that small-molecule HDAC6 inhibitors selectively killed DNMT3A-defective NSCLC cells. Knockdown of HDAC6 by siRNAs reduced cell growth and induced apoptosis in DNMT3A-defective NSCLC cells. However, sensitive cells became resistant when DNMT3A was rescued. Furthermore, the selectivity to HDAC6 inhibition was recapitulated in mice, where an HDAC6 inhibitor retarded tumor growth established from DNMT3A-defective but not DNMT3A parental NSCLC cells. Mechanistically, DNMT3A loss resulted in the upregulation of HDAC6 through decreasing its promoter CpG methylation and enhancing transcription factor RUNX1 binding. Notably, our results indicated that HIF-1 pathway was activated in DNMT3A-defective cells whereas inactivated by HDAC6 inhibition. Knockout of HIF-1 contributed to the elimination of synthetic lethality between DNMT3A and HDAC6. Interestingly, HIF-1 pathway inhibitors could mimic the selective efficacy of HDAC6 inhibition in DNMT3A-defective cells. These results demonstrated HDAC6 as a HIF-1-dependent vulnerability of DNMT3A-defective cancers. Together, our findings identify HDAC6 as a potential HIF-1-dependent therapeutic target for the treatment of DNMT3A-defective cancers like NSCLC.

Humans ; COVID-19 ; Consensus ; SARS-CoV-2 ; China

Objective:To investigate the incidence and risk factors of human cytomegalovirus (HCMV) reactivation in immunocompetent severe pneumonia patients with mechanical ventilation and their effects on clinical outcomes.Methods:A prospective observational study was conducted. Forty-eight immunocompetent patients requiring invasive mechanical ventilation due to severe pneumonia in the department of critical care medicine of the First Affiliated Hospital of Guangzhou Medical University from June 30th, 2017 to July 1st, 2018 were enrolled. Meanwhile, all cases were followed up until 90 days after inclusion and were required to quantitatively detect HCMV DNA in serum at regular weekly intervals until 28 days after transferring to intensive care unit (ICU). Patients were divided into HCMV reactivation group (≥5×10 5 copies/L) and non-reactivation group (<5×10 5 copies/L) based on HCMV DNA at any time point within 28 days. Demographic data, basic indicators, respiratory indicators, disease severity scores, laboratory indicators, complication and clinical outcomes of the two groups were collected and analyzed. Multivariate Logistic regression analysis was performed to screen independent risk factors for HCMV reactivation. Results:All 48 subjects were tested positive for HCMV immunoglobulin G (IgG), so HCMV seropositive rate was 100%. HCMV reactivation occurred in 10 patients within 28 days after admission to ICU, and the reactivation incidence of HCMV was 20.83%. There was no significant difference in gender, age, body mass index (BMI), underling disease reasons for ICU transfer (except sepsis), basic vital signs, disease severity scores, or laboratory findings including infection, immune, blood routine, liver, kidney and circulatory indicators except neutrophils count (NEU), hypersensitivity C-reactive protein(hs-CRP), hemoglobin (Hb), blood urea nitrogen (BUN), N-terminal pro-brain natriuretic peptide (NT-proBNP) between the two groups. The height (cm: 160±6 vs. 166±8), body weight (kg: 49.4±11.2 vs. 57.6±10.5), Hb (g/L: 87±18 vs. 104±24) in HCMV reactivation group were significantly lower than non-reactivation group, as well as NEU [×10 9/L:12.7 (9.9, 22.5) vs. 8.9 (6.2, 13.8)], hs-CRP [mg/L: 115.5 (85.2, 136.6) vs. 39.9 (17.5, 130.2)], BUN [mmol/L:13.7 (8.9, 21.5) vs. 7.1 (4.9, 10.5)] and NT-proBNP [ng/L: 6 751 (2 222, 25 449) vs. 1 469 (419, 4 571)] within 24 hours of admission to ICU. The prevalence of sepsis [60.0% (6/10) vs. 15.8% (6/38)], blood transfusion [100.0% (10/10) vs. 60.5% (23/38)], hospitalization expense [ten thousand yuan: 35.7 (25.3, 67.1) vs. 15.2 (10.4, 22.0)], 90-day all-cause mortality [70.0% (7/10) vs. 21.1% (8/38)], length of ICU stay [days: 26 (16, 66) vs. 14 (9, 19)], the duration of mechanical ventilation [days: 26 (19, 66) vs. 13 (8, 18)] in HCMV reactivation group were significantly higher than non-reactivation group, and there were significant statistical differences between the two groups (all P < 0.05). Logistic regression analysis showed that sepsis was an independent risk factor for HCMV reactivation in immunocompetent mechanical ventilation severe pneumonia patients with mechanical ventilation [odds ratio ( OR) = 9.35, 95% confidence interval (95% CI) was 1.72-50.86, P = 0.010]. Conclusions:HCMV infection is very common in immunocompetent severe pneumonia patients on mechanical ventilation and incidence of HCMV reactivation is high. Moreover, HCMV reactivation could adversely affect clinical prognoses, and sepsis may be a risk factor for HCMV reactivation.

Objective:To investigate the incidence and risk factors of active human cytomegalovirus (HCMV) infection in patients with severe community-acquired pneumonia.Methods:Patients who required respiratory support and were diagnosed with severe community-acquired pneumonia in the respiratory intensive care unit (RICU) of the First Affiliated Hospital of Guangzhou Medical University from March 1, 2019 to June 1, 2020 were consecutively screened and divided into active HCMV infection group (20 cases) and non-active HCMV infection group (95 cases) based on whether a patient has active HCMV infection or not. Differences in demographic data, laboratory findings, and clinical outcomes were compared between the two groups. Moreover, logistic regression was applied to analyze risk factors for active HCMV infection.Results:The 20 of 115 patients with severe community-acquired pneumonia requiring respiratory support were confirmed to have active infection with HCMV, with a prevalence of active HCMV infection of 17.4%. The pneumonia severity index (PSI) and suppressor T lymphocytes (Ts) in active HCMV infection group were higher than that of the control group, and all the differences were statistically significant ( Z=2.432, P=0.015; Z=2.036, P=0.042); whereas lymphocytes, monocytes, blood lactate, and platelet levels were lower than those of the control group, and all the differences were statistically significant ( P < 0.05). Patients with active HCMV infection had a higher transfusion rate than the control group, and the differences were statistically significant (χ 2=3.941; P=0.047). Increasing levels of PSI and Ts percentage were independent risk factors for active HCMV infection ( OR=1.03, 95% CI: 1.01~1.05; OR=1.06, 95% CI: 1.00~1.11; P < 0.05). RICU length of stay, complication rates, and 90-day all-cause mortality were higher in the active HCMV infection group than the control group, and all the differences were statistically significant ( P < 0.05). Conclusions:Active HCMV infection is highly prevalent in patients with severe community-acquired pneumonia and associated with several adverse clinical outcomes, with PSI and Ts cell levels being independent risk factors.

Objective To evaluate the relationship between the hippocampal neuron-protective mechanism of hydrogen in a rat model of oxygen-glucose deprivation and restoration(OGD/R)and mito-chondrial autophagy.Methods Hippocampal neurons isolated from healthy Sprague-Dawley rats(24 h af-ter birth)were cultured in vitro,seeded in polylysine-coated 6-well plates at a density of 7×105 cells/well and then divided into 5 groups(n＝30 each)using a random number table method: control group(C group),OGD/R group,OGD/R+H2 group,OGD/R plus 3-methyladenine(3-MA)group(OGD/R+3-MA group),and OGD/R plus H2 plus 3-MA group(OGD/R+H2+3-MA group).The cells were cultured for 24 h in normal culture atmosphere(75％N2-20％O2-5％CO2)in group C,and cells were subjected to oxygen-glucose deprivation for 2 h followed by O2-glucose supply for 24 h to establish the model of OGD/R injury in OGD/R,OGD/R+H2,OGD/R+3-MA and OGD/R+H2+3-MA groups.The cells were cultured for 24 h in a hydrogen-rich incubator(60％H2-10％O2-5％CO2-25％N2)after establishing the model in group OGD/R+H2.Autophagy inhibitor 3-MA 10 mmol/L was added,and then cultured for 24 h in normal culture atmosphere after establishing the model in group OGD/R+3-MA.Autophagy inhibitor 3-MA 10 mmol/L was added,and then cultured for 24 h in hydrogen-rich incubator after establishing the model in group OGD/R+H2+3-MA.The cell survival rate was measured using MTT assay.DCFH-DA fluorescent probe was applied for determination of reactive oxygen species(ROS)activity.The mitochondrial membrane potential was measured using a JC-10 assay kit.The neuronal apoptosis was detected by flow cytometry,and apoptosis rate was calculated.The expression of mitophagy-related protein microtubule-associated protein 1 light chain 3(LC3),PINK1 and Parkin was determined by Western blot,and LC3Ⅱ/LC3Ⅰ ratio was calculated.Results Compared with group C,the cell survival rate and MMP were significantly decreased,the apop-tosis rate and ROS activity were increased,and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰrati-o were increased in OGD/R and OGD/R+H2 groups(P＜0.05).Compared with group OGD/R,the cell survival rate and MMP were significantly increased,the apoptosis rate and ROS activity were decreased,and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were increased in group OGD/R+H2(P＜0.05),and the cell survival rate and MMP were significantly decreased,the apoptosis rate and ROS activ-ity were increased,and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were decreased in group OGD/R+3-MA(P＜0.05).Compared with group OGD/R+H2,the cell survival rate and MMP were significantly decreased,the apoptosis rate and ROS activity were increased,and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were decreased in OGD/R+3-MA and OGD/R+H2+3-MA groups(P＜0.05).Conclusion Hippocampal neuron-protective mechanism of hydrogen against OGDR injury is relat-ed to promoting mitochondrial autophagy in rats.

Objective: To evaluate the relationship between the hippocampal neuron-protective mechanism of hydrogen in a rat model of oxygen-glucose deprivation and restoration (OGD/R) and mitochondrial autophagy. Methods: Hippocampal neurons isolated from healthy Sprague-Dawley rats (24 h after birth) were cultured in vitro, seeded in polylysine-coated 6-well plates at a density of 7×10⁵ cells/well and then divided into 5 groups (n=30 each) using a random number table method: control group (C group), OGD/R group, OGD/R+ H₂ group, OGD/R plus 3-methyladenine (3-MA) group (OGD/R+ 3-MA group), and OGD/R plus H₂ plus 3-MA group (OGD/R+ H₂+ 3-MA group). The cells were cultured for 24 h in normal culture atmosphere (75%N₂-20%O₂-5%CO₂) in group C, and cells were subjected to oxygen-glucose deprivation for 2 h followed by O₂-glucose supply for 24 h to establish the model of OGD/R injury in OGD/R, OGD/R+ H₂, OGD/R+ 3-MA and OGD/R+ H₂+ 3-MA groups.The cells were cultured for 24 h in a hydrogen-rich incubator (60% H₂-10% O₂-5% CO₂-25% N₂) after establishing the model in group OGD/R+ H₂.Autophagy inhibitor 3-MA 10 mmol/L was added, and then cultured for 24 h in normal culture atmosphere after establishing the model in group OGD/R+ 3-MA.Autophagy inhibitor 3-MA 10 mmol/L was added, and then cultured for 24 h in hydrogen-rich incubator after establishing the model in group OGD/R+ H₂+ 3-MA.The cell survival rate was measured using MTT assay.DCFH-DA fluorescent probe was applied for determination of reactive oxygen species (ROS) activity.The mitochondrial membrane potential was measured using a JC-10 assay kit.The neuronal apoptosis was detected by flow cytometry, and apoptosis rate was calculated.The expression of mitophagy-related protein microtubule-associated protein 1 light chain 3 (LC3), PINK1 and Parkin was determined by Western blot, and LC3Ⅱ/LC3Ⅰ ratio was calculated. Results: Compared with group C, the cell survival rate and MMP were significantly decreased, the apoptosis rate and ROS activity were increased, and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were increased in OGD/R and OGD/R+ H₂ groups (P<0.05). Compared with group OGD/R, the cell survival rate and MMP were significantly increased, the apoptosis rate and ROS activity were decreased, and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were increased in group OGD/R+ H₂(P<0.05), and the cell survival rate and MMP were significantly decreased, the apoptosis rate and ROS activity were increased, and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were decreased in group OGD/R+ 3-MA (P<0.05). Compared with group OGD/R+ H₂, the cell survival rate and MMP were significantly decreased, the apoptosis rate and ROS activity were increased, and the expression of PINK1 and Parkin and LC3Ⅱ/LC3Ⅰ ratio were decreased in OGD/R+ 3-MA and OGD/R+ H₂+ 3-MA groups (P<0.05). Conclusion Hippocampal neuron-protective mechanism of hydrogen against OGDR injury is related to promoting mitochondrial autophagy in rats.

Objective To evaluate the effect of dexmedetomidine on necroptosis during liver injury in septic rats.Methods Eighteen SPF adult male Sprague-Dawley rats,weighing 200-220 g,were divided into 3 groups (n=6 each) using a random number table:sham operation group (group SH),sepsis group (group SEP) and dexmedetomidine group (group DEX).Sepsis was induced by cecal ligation and puncture in chloral hydrate-anesthetized rats in SEP and DEX groups.Dexmedetomidine 5 μg/kg was injected via the caudal vein at 1 h before operation in group DEX.Blood samples were collected from the caudal vein at 6 h after operation for determination of serum aspartate amino-transferase (AST) and alanine aminotransferase (ALT) concentrations.The rats were then sacrificed and livers were removed for determination of the level of reactive oxygen species (ROS) in liver tissues (using chemiluminescence assay) and expression of receptor-interacting protein 1 (RIP1),RIP3,mixed lineage kinase domain-like (MLKL),high-mobility group box 1 protein (HMGB1) and dynamin-related protein 1 (Drpl) in liver tissues (by Western blot).Results Compared with group SH,the serum AST and ALT concentrations were significantly increased,the expression of RIP1,RIP3,MLKL,HMGB1 and Drpl in liver tissues was up-regulated,and the level of ROS in liver tissues was increased in SEP and DEX groups (P＜0.05).Compared with group SEP,the serum AST and ALT concentrations were significantly decreased,the expression of RIP1,RIP3,MLKL,HMGB1 and Drp1 in liver tissues was down-regulated,and the level of ROS in liver tissues was decreased in group DEX (P＜0.05).Conclusion The mechanism by which dexmedetomidine attenuates liver injury may be related to inhibition of necroptosis in septic rats.

Objective To evaluate the role of necroptosis in liver injury in septic rats.Methods Twenty-four SPF healthy male adult Sprague-Dawley rats,weighing 200-220 g,aged 6-8 weeks,were divided into 3 groups (n=8 each) using a random number table:sham operation group (Sh group),sepsis group (Sep group) and specific necroptosis inhibitor necrostatin-1 group (N group).Sepsis was induced by cecal ligation and puncture in anesthetized rats in N and Sep groups.Necrostatin-1 1.0 mg/kg was intravenously injected at 1 h before operation in group N,while the equal volume of dimethyl sulfoxide was given instead in group Sep.Rats were sacrificed at 6 h after operation,and livers were removed for examination of the pathological changes (with a light microscope) and for determination of the level of reactive oxygen species (ROS) in liver tissues (by using chemiluminescence assay) and expression of receptor-interacting protein kinase-1 (RIPK1),RIPK3,mixed lineage kinase domain-like (MLKL) and high-mobility group box 1 protein (HMGB1) in liver tissues (using Western blot).Results Compared with Sh group,the ROS level in liver tissues was significantly increased,and the expression of RIPK1,RIPK3,MLKL and HMGB1 in liver tissues was up-regulated in Sep and N groups (P＜0.05).Compared with Sep group,the ROS level in liver tissues was significantly decreased,and the expression of RIPK1,RIPK3,MLKL and HMGB 1 in liver tissues was down-regulated in group N (P＜0.05).The pathological changes of liver tissues were significantly attenuated in group N when compared with group Sep.Conclusion Neeroptosis is involved in liver injury in septic rats.

Objective To evaluate the effect of Toll-like receptor 7 (TLR7) agonist on c-Jun Nterminal kinase (JNK) signaling pathway during liver injury in the septic mice.Methods One hundred eighty pathogen-free adult male C57BL/6 mice,aged 10-14 weeks,weighing 20-26 g,were randomly divided into 3 groups (n=60 each) using a random number table:sham operation group (group S);sepsis group (group Sep);TLR7 agonist group (group GDQ).Sepsis was induced by cecum ligation and puncture.In group GDQ,TLR7 agonist 1.5 g/kg was injected intraperitoneally at 24 h before establishment of the model.At 6,12 and 24 h after operation,10 mice in each group were sacrificed,and the livers were removed to detect the expression of interleukin-6 (IL-6) and IL-10 by Western blot.The expression of JNK was determined by immuno-histochemistry,and the histopathologic changes of livers were examined with a light microscope at 24 h after operation.The survival of mice was observed at 14 days after operation,and the 14-day survival rates were calculated.Results Compared with group S,the 14-day survival rates were significantly decreased,and the expression of IL-6,IL-10 and JNK was significantly up-regulated at 6,12 and 24 h after operation in Sep and GDQ groups (P＜0.05).Compared with group Sep,the 14-day survival rates were significantly increased,and the expression of IL-6,IL-10 and JNK was significantly down-regulated at 6,12 and 24 h after operation in group GDQ (P＜0.05).The pathological changes of livers were significantly attenuated in group GDQ as compared with group Sep.Conclusion TLR7 agonist can reduce the liver injury through blocking the JNK signaling pathway in the septic mice.