Obstructive Fibrinous Tracheal Pseudomembrane Following Repeated Intratracheal Interventions.

Obstructive fibrinous tracheal pseudomembrane (OFTP) is a relatively rare complication of endotracheal intubation. Despite being well documented, the exact pathogenesis of OFTP remains unclear. Some studies suggest that it may arise from the early stage of ischemic tracheal wall injury caused by the cuff pressure during intubation. Diagnosis and treatment of OFTP can be facilitated through therapeutic bronchoscopy. In this case report, we describe a patient who presented with dyspnea following repeated intratracheal interventions and was diagnosed with OFTP. The patient was successfully treated with bronchoscopic cryotherapy and was subsequently discharged from the hospital.

Effects of Prone Positioning for Patients with Acute Respiratory Distress Syndrome Caused by Pulmonary Contusion: A Single-Center Retrospective Study.

Background: The effects of prone positioning (PP) on patients with acute respiratory distress syndrome (ARDS) caused by pulmonary contusion (PC) are unclear. We sought to determine the efficacy of PP among patients whose ARDS was caused by PC. Methods: A retrospective observational study was performed at an intensive care unit (ICU) from January 2017 to June 2021. ARDS patients with PaO2/FiO2 (P/F) < 150 mmHg were enrolled. During the study period, we enrolled 121 patients in the PP group and 117 in the control group. The changes in vital signs, laboratory tests, and compliance of the respiratory system (Crs) were recorded for 3 consecutive days. The mechanical ventilation time, duration of ICU stay, complications, extubation rate, 28-day ventilator-free days, and mortality were also recorded. Results: In the PP group, the P/F and Crs increased over time. Compared to the control group, the P/F and Crs improved in the PP group over 3 consecutive days (P < 0.05). Furthermore, the PP group also had shorter total mechanical ventilation time (5.1 ± 1.4 vs. 9.3 ± 3.1 days, P < 0.05) and invasive ventilation time (4.9 ± 1.2 vs. 8.7 ± 2.7 days, P < 0.05), shorter ICU stay (7.4 ± 1.8 vs. 11.5 ± 3.6days, P < 0.05), higher extubation rate (95.6% vs. 84.4%, P < 0.05), less atelectasis (15 vs. 74, P < 0.05) and pneumothorax (17 vs. 24, P > 0.05), more 28-day ventilator-free days (21.6 ± 5.2 vs. 16.2 ± 7.2 days, P < 0.05), and lower mortality (4.4% vs. 13.3%, P < 0.05). Conclusions: Among PC cases with moderate to severe ARDS, PP can correct hypoxemia more quickly, improve Crs, reduce atelectasis, increase the extubation rate, shorten mechanical ventilation time and length of ICU stay, and reduce mortality.

Hepatic portal venous gas: A case report and analysis of 131 patients using PUBMED and MEDLINE database.

OBJECTIVE: Hepatic portal pneumatosis has a high mortality rate, and whether surgical intervention is necessary remains controversial. This experiment retrospectively analyzed the etiology, treatment methods and prognosis of adult patients with hepatoportal pneumocele to provide a theoretical basis for the treatment of this disease. METHODS: We analyzed the clinical symptoms and post-treatment of a 43-year-old male patient with HPVG admitted to hospital. We retrieved adult non-iatrogenic HPVG cases with complete clinical data in PUBMED,  and MEDLINE and other databases were retrieved for analysis, and summarized the pathogenesis, clinical symptoms, pathogenesis, pathogenesis and prognosis of different treatment schemes were summarized. RESULTS: The main etiology of HPVG are intestinal ischemia (27%), severe enteritis/intestinal perforation/intestinal fistula (16%), intestinal obstruction (7%), abdominal infection (7%), gastric diseases (11%), appendicitis and its complications (5%), acute hemorrhage or necrotizing pancreatitis (5%), Crohn's disease and its complications (4%), trauma (traffic accidents, falls) (2%), diverticulitis and perforation (6%), nephrogenic diseases (4%), spontaneous pneumohepatic portal vein (2%), other reasons (4%). And after analysis, we found that the survival rate of patients treated by surgery was 40.5% and the mortality rate was 19.1%, the difference between the two was significant. CONCLUSIONS: Etiology should be actively explored and surgical treatment is necessary.

Analgesic therapy improves arterial endothelial function following non-cardiovascular surgery: A randomized, placebo-controlled trial.

Pain subsequent to non-cardiac surgery may affect the endothelial function, which in turn contributes to myocardial injury (MI). The present study examined whether effective pain control is able to improve the postoperative endothelial function. Patients (n=160) undergoing laparoscopic cholecystectomy were randomly assigned into two groups, treated with tramadol analgesic or saline (placebo) following surgery. On preoperative day 1 (baseline) and postoperatively at 2 h, 1 day and 5 days, pain was assessed on a visual analogue scale (VAS), and B-mode ultrasound was used to measure brachial endothelium-dependent flow-mediated dilation (FMD) and nitroglycerin-induced dilation. At 2 h postoperatively, the FMD in the two groups was significantly lower compared with that at the other three time points (P≤0.005), while VAS was significantly higher (P<0.05). Patients in the tramadol group presented significantly reduced VAS values in comparison with those in the placebo group at 2 h and 1 day postoperatively (P=0.013 and 0.031, respectively), as well as significantly higher FMD at 2 h (6.7±1.5 vs. 6.0±1.7%; P=0.001) and 1 day postoperatively (7.3±1.3 vs. 6.9±1.4%; P=0.03). A VAS score of <5 was independently associated with postoperative FMD of ≥7 (odds ratio, 2.5; 95% confidence interval, 1.0-6.0; P=0.047). Backward multivariate linear regression also demonstrated that FMD was independently correlated with age and VAS score (B=-1.403, P=0.011; B=-0.579, P=0.003). The response to nitroglycerin-induced dilation remained stable in all patients at baseline and at all postoperative time points. In conclusion, analgesic treatment may improve the arterial endothelial function following non-cardiac surgery, which may help prevent postoperative MI.

SPAG9 controls the cell motility, invasion and angiogenesis of human osteosarcoma cells.

Sperm-associated antigen 9 (SPAG9) is an oncoprotein involved in the progression of various human malignancies; however, its role in osteosarcoma (OS) remains poorly evaluated. The present study used Matrigel™ cell migration and invasion assays, tube formation assay, Cell Counting kit-8, quantitative polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay to investigate the role of SPAG9 in OS cell motility, invasion and angiogenesis. The results of the present study demonstrated that SPAG9 expression was upregulated in OS tissues, as compared with adjacent normal tissues, and knockdown of SPAG9 in an OS cell line inhibited cell motility and invasion via inactivation of metalloproteinase (MMP)-2 and MMP-9. Furthermore, the present study demonstrated that silencing of SPAG9 in OS cells inhibited tube formation, the proliferation of human umbilical vascular endothelial cells, and suppressed vascular endothelial growth factor (VEGF) expression and secretion, contributing to a reduction in angiogenesis. The results of the present study indicated that SPAG9 may be an important regulator in OS and may be involved in metastasis. Therefore SPAG9 may be a promising target for the treatment of metastatic OS.

The novolactone natural product disrupts the allosteric regulation of Hsp70.

The highly conserved 70 kDa heat shock proteins (Hsp70) play an integral role in proteostasis such that dysregulation has been implicated in numerous diseases. Elucidating the precise role of Hsp70 family members in the cellular context, however, has been hampered by the redundancy and intricate regulation of the chaperone network, and relatively few selective and potent tools. We have characterized a natural product, novolactone, that targets cytosolic and ER-localized isoforms of Hsp70 through a highly conserved covalent interaction at the interface between the substrate-binding and ATPase domains. Biochemical and structural analyses indicate that novolactone disrupts interdomain communication by allosterically inducing a conformational change in the Hsp70 protein to block ATP-induced substrate release and inhibit refolding activities. Thus, novolactone is a valuable tool for exploring the requirements of Hsp70 chaperones in diverse cellular contexts.

Identification of mixed lineage leukemia 1(MLL1) protein as a coactivator of heat shock factor 1(HSF1) protein in response to heat shock protein 90 (HSP90) inhibition.

Heat shock protein 90 (HSP90) inhibition inhibits cancer cell proliferation through depleting client oncoproteins and shutting down multiple oncogenic pathways. Therefore, it is an attractive strategy for targeting human cancers. Several HSP90 inhibitors, including AUY922 and STA9090, show promising effects in clinical trials. However, the efficacy of HSP90 inhibitors may be limited by heat shock factor 1 (HSF1)-mediated feedback mechanisms. Here, we identify, through an siRNA screen, that the histone H3 lysine 4 methyltransferase MLL1 functions as a coactivator of HSF1 in response to HSP90 inhibition. MLL1 is recruited to the promoters of HSF1 target genes and regulates their expression in response to HSP90 inhibition. In addition, a striking combination effect is observed when MLL1 depletion is combined with HSP90 inhibition in various human cancer cell lines and tumor models. Thus, targeting MLL1 may block a HSF1-mediated feedback mechanism induced by HSP90 inhibition and provide a new avenue to enhance HSP90 inhibitor activity in human cancers.

Phosphoglycerate dehydrogenase is dispensable for breast tumor maintenance and growth.

Cancer cells rely on aerobic glycolysis to maintain cell growth and proliferation via the Warburg effect. Phosphoglycerate dehydrogenase (PHDGH) catalyzes the first step of the serine biosynthetic pathway downstream of glycolysis, which is a metabolic gatekeeper both for macromolecular biosynthesis and serine-dependent DNA synthesis. Here, we report that PHDGH is overexpressed in many ER-negative human breast cancer cell lines. PHGDH knockdown in these cells leads to a reduction of serine synthesis and impairment of cancer cell proliferation. However, PHGDH knockdown does not affect tumor maintenance and growth in established breast cancer xenograft models, suggesting that PHGDH-dependent cancer cell growth may be context-dependent. Our findings suggest that other mechanisms or pathways may bypass exclusive dependence on PHGDH in established human breast cancer xenografts, indicating that PHGDH is dispensable for the growth and maintenance and of tumors in vivo.

An F876L mutation in androgen receptor confers genetic and phenotypic resistance to MDV3100 (enzalutamide).

UNLABELLED: Castration-resistant prostate cancer (CRPC) is the most aggressive, incurable form of prostate cancer. MDV3100 (enzalutamide), an antagonist of the androgen receptor (AR), was approved for clinical use in men with metastatic CRPC. Although this compound showed clinical efficacy, many initial responders later developed resistance. To uncover relevant resistant mechanisms, we developed a model of spontaneous resistance to MDV3100 in LNCaP prostate cancer cells. Detailed characterization revealed that emergence of an F876L mutation in AR correlated with blunted AR response to MDV3100 and sustained proliferation during treatment. Functional studies confirmed that AR(F876L) confers an antagonist-to-agonist switch that drives phenotypic resistance. Finally, treatment with distinct antiandrogens or cyclin-dependent kinase (CDK)4/6 inhibitors effectively antagonized AR(F876L) function. Together, these findings suggest that emergence of F876L may (i) serve as a novel biomarker for prediction of drug sensitivity, (ii) predict a "withdrawal" response to MDV3100, and (iii) be suitably targeted with other antiandrogens or CDK4/6 inhibitors. SIGNIFICANCE: We uncovered an F876L agonist-switch mutation in AR that confers genetic and phenotypic resistance to the antiandrogen drug MDV3100. On the basis of this fi nding, we propose new therapeutic strategies to treat patients with prostate cancer presenting with this AR mutation.

Targeting HSF1 sensitizes cancer cells to HSP90 inhibition.

The molecular chaperone heat shock protein 90 (HSP90) facilitates the appropriate folding of various oncogenic proteins and is necessary for the survival of some cancer cells. HSP90 is therefore an attractive drug target, but the efficacy of HSP90 inhibitor may be limited by HSP90 inhibition induced feedback mechanisms. Through pooled RNA interference screens, we identified that heat shock factor 1(HSF1) is a sensitizer of HSP90 inhibitor. A striking combinational effect was observed when HSF1 knockdown plus with HSP90 inhibitors treatment in various cancer cell lines and tumor mouse models. Interestingly, HSF1 is highly expressed in hepatocellular carcinoma (HCC) patient samples and HCC is sensitive to combinational treatment, indicating a potential indication for the combinational treatment. To understand the mechanism of the combinational effect, we identified that a HSF1-target gene DEDD2 is involved in attenuating the effect of HSP90 inhibitors. Thus, the transcriptional activities of HSF1 induced by HSP90 inhibitors provide a feedback mechanism of limiting the HSP90 inhibitor's activity, and targeting HSF1 may provide a new avenue to enhance HSP90 inhibitors activity in human cancers.

Histone H2A ubiquitination in transcriptional regulation and DNA damage repair.

The precise molecular strategies that coordinate patterns of transcriptional response to specific signals is central for understanding normal development and disease. Precise control of transcriptional programs underlying metazoan development is modulated by enzymatically active coregulatory complexes, coupled with epigenetic strategies. Epigenetic modifications, particularly DNA methylation and covalent histone modifications, for instance acetylation, methylation, phosphorylation and ubiquitination, play an essential role in transcription regulation, chromatin remodeling, genome instability and X chromosome inactivation. Recently, the ubiquitinases and deubiquitinases responsible for histone H2A ubiquitination and deubiquitination have been identified and characterized. These studies suggest that histone H2A ubiquitination play important roles in many cellular events, such as transcription initiation and elongation, silencing, and DNA repair. Alteration of histone H2A ubiquitination modifications may contribute human diseases, such as cancer. In this review, we discuss enzymes involved in H2A ubiquitination/deubiquitination and that possible molecular mechanisms underlying histone H2A ubiquitination/deubiquitination in transcriptional regulation and DNA damage repair.

Histone H2A monoubiquitination represses transcription by inhibiting RNA polymerase II transcriptional elongation.

Solving the biological roles of covalent histone modifications, including monoubiquitination of histone H2A, and the molecular mechanisms by which these modifications regulate specific transcriptional programs remains a central question for all eukaryotes. Here we report that the N-CoR/HDAC1/3 complex specifically recruits a specific histone H2A ubiquitin ligase, 2A-HUB/hRUL138, to a subset of regulated gene promoters. 2A-HUB catalyzes monoubiquitination of H2A at lysine 119, functioning as a combinatoric component of the repression machinery required for specific gene regulation programs. Thus, 2A-HUB mediates a selective repression of a specific set of chemokine genes in macrophages, critically modulating migratory responses to TLR activation. H2A monoubiquitination acts to prevent FACT recruitment at the transcriptional promoter region, blocking RNA polymerase II release at the early stage of elongation. We suggest that distinct H2A ubiquitinases, each recruited based on interactions with different corepressor complexes, contribute to distinct transcriptional repression programs.

Modulation of morphogenesis by noncanonical Wnt signaling requires ATF/CREB family-mediated transcriptional activation of TGFbeta2.

Transcriptional readout downstream of canonical Wnt signaling is known to be mediated by beta-catenin activation of well-described targets, but potential transcriptional readout in response to noncanonical Wnt signaling remains poorly understood. Here, we define a transcriptional pathway important in noncanonical Wnt signaling. We have found that Wnt11 is a direct target of a canonical beta-catenin pathway in developing heart and that Wnt11 mutants show cardiac outflow tract defects. We provide genetic and biochemical evidence thatWnt11 signaling affects extracellular matrix composition, cytoskeletal rearrangements and polarized cell movement required for morphogenesis of the cardiac outflow tract. Notably, transforming growth factor beta2 (TGFbeta2), a key effector of organ morphogenesis, is regulated by Wnt11-mediated noncanonical signaling in developing heart and somites via one or more activating transcription factor (ATF)/cyclic AMP response element binding protein (CREB) family members. Thus, we propose that transcriptional readout mediated at least in part by a Wnt11 --> ATF/CREB --> TGFbeta2 pathway is critical in regulating morphogenesis in response to noncanonical Wnt signaling.

A histone H2A deubiquitinase complex coordinating histone acetylation and H1 dissociation in transcriptional regulation.

Deciphering the epigenetic "code" remains a central issue in transcriptional regulation. Here, we report the identification of a JAMM/MPN(+) domain-containing histone H2A deubiquitinase (2A-DUB, or KIAA1915/MYSM1) specific for monoubiquitinated H2A (uH2A) that has permitted delineation of a strategy for specific regulatory pathways of gene activation. 2A-DUB regulates transcription by coordinating histone acetylation and deubiquitination, and destabilizing the association of linker histone H1 with nucleosomes. 2A-DUB interacts with p/CAF in a coregulatory protein complex, with its deubiquitinase activity modulated by the status of acetylation of nucleosomal histones. Consistent with this mechanistic role, 2A-DUB participates in transcriptional regulation events in androgen receptor-dependent gene activation, and the levels of uH2A are dramatically decreased in prostate tumors, serving as a cancer-related mark. We suggest that H2A ubiquitination represents a widely used mechanism for many regulatory transcriptional programs and predict that various H2A ubiquitin ligases/deubiquitinases will be identified for specific cohorts of regulated transcription units.

Beta-catenin directly regulates Islet1 expression in cardiovascular progenitors and is required for multiple aspects of cardiogenesis.

Recent studies have demonstrated that the LIM homeodomain transcription factor Islet1 (Isl1) marks pluripotent cardiovascular progenitor cells and is required for proliferation, survival, and migration of recently defined second heart field progenitors. Factors that are upstream of Isl1 in cardiovascular progenitors have not yet been defined. Here we demonstrate that beta-catenin is required for Isl1 expression in cardiac progenitors, directly regulating the Isl1 promoter. Ablation of beta-catenin in Isl1-expressing progenitors disrupts multiple aspects of cardiogenesis, resulting in embryonic lethality at E13. beta-Catenin is also required upstream of a number of genes required for pharyngeal arch, outflow tract, and/or atrial septal morphogenesis, including Tbx2, Tbx3, Wnt11, Shh, and Pitx2. Our findings demonstrate that beta-catenin signaling regulates proliferation and survival of cardiac progenitors.

Repression of human gamma-globin gene expression by a short isoform of the NF-E4 protein is associated with loss of NF-E2 and RNA polymerase II recruitment to the promoter.

Binding of the stage selector protein (SSP) to the stage selector element (SSE) in the human gamma-globin promoter contributes to the preferential expression of the gamma-gene in fetal erythroid cells. The SSP contains the transcription factor CP2 and an erythroid-specific partner, NF-E4. The NF-E4 gene encodes a 22-kDa polypeptide employing a non-AUG initiation codon. Antisera specific to NF-E4 detects this species and an additional 14 kDa protein, which initiates from an internal methionine. Enforced expression of p14 NF-E4 in the K562 fetal/erythroid cell line, and in primary erythroid cord blood progenitors, results in repression of gamma-gene expression. Biochemical studies reveal that p14 NF-E4 interacts with CP2, resulting in diminished association of CP2 with the SSE in chromatin immunoprecipitation assays. p45 NF-E2 recruitment to the gamma-promoter is also lost, resulting in a reduction in RNA polymerase II and TBP binding and a fall in promoter transcriptional activity. This effect is specific, as enforced expression of a mutant form of p14 NF-E4, which fails to interact with CP2, also fails to repress gamma-gene expression in K562 cells. These findings provide one potential mechanism that could contribute to the autonomous silencing of the human gamma-genes in adult erythroid cells.

T-box genes coordinate regional rates of proliferation and regional specification during cardiogenesis.

Mutations in T-box genes are the cause of several congenital diseases and are implicated in cancer. Tbx20-null mice exhibit severely hypoplastic hearts and express Tbx2, which is normally restricted to outflow tract and atrioventricular canal, throughout the heart. Tbx20 mutant hearts closely resemble those seen in mice overexpressing Tbx2 in myocardium, suggesting that upregulation of Tbx2 can largely account for the cardiac phenotype in Tbx20-null mice. We provide evidence that Tbx2 is a direct target for repression by Tbx20 in developing heart. We have also found that Tbx2 directly binds to the Nmyc1 promoter in developing heart, and can repress expression of the Nmyc1 promoter in transient transfection studies. Repression of Nmyc1 (N-myc) by aberrantly regulated Tbx2 can account in part for the observed cardiac hypoplasia in Tbx20 mutants. Nmyc1 is required for growth and development of multiple organs, including the heart, and overexpression of Nmyc1 is associated with childhood tumors. Despite its clinical relevance, the factors that regulate Nmyc1 expression during development are unknown. Our data present a paradigm by which T-box proteins regulate regional differences in Nmyc1 expression and proliferation to effect organ morphogenesis. We present a model whereby Tbx2 directly represses Nmyc1 in outflow tract and atrioventricular canal of the developing heart, resulting in relatively low proliferation. In chamber myocardium, Tbx20 represses Tbx2, preventing repression of Nmyc1 and resulting in relatively high proliferation. In addition to its role in regulating regional proliferation, we have found that Tbx20 regulates expression of a number of genes that specify regional identity within the heart, thereby coordinating these two important aspects of organ development.

The role of p22 NF-E4 in human globin gene switching.

The human stage selector protein, a complex containing the ubiquitous transcription factor CP2 and the erythroid-specific factor p22 NF-E4, facilitates the interaction of the gamma-globin genes with the locus control region in fetal erythroid cells. Enforced expression of p22 NF-E4 in K562 cells and human cord blood progenitors increases fetal globin gene expression, and in progenitors, reduces beta-globin expression. To examine the role of NF-E4 in an in vivo model of hemoglobin switching, we enforced the expression of p22 NF-E4 in transgenic mice carrying the human beta-globin locus yeast artificial chromosome. Although murine erythropoiesis and globin gene expression is unaffected in these mice, the expression profile of the human globin genes is altered. All three transgenic lines displayed an increased gamma:beta-globin ratio in E12.5-14.5 fetal liver, resulting in a delay in the fetal/adult switch. At E12.5, this is primarily due to a reduction of beta-gene expression, whereas at E14.5, the increased gamma:beta ratio is due to enhanced gamma-gene expression. Despite this, the switch in globin subtype is fully completed in the adult bone marrow. These findings indicate that p22 NF-E4 is capable of influencing human globin gene expression in vivo but is incapable of overriding the intrinsic mechanisms governing gamma-gene silencing in this context.