USP22 antagonizes p53 transcriptional activation by deubiquitinating Sirt1 to suppress cell apoptosis and is required for mouse embryonic development

The NAD-dependent histone deacetylase Sirt1 antagonizes p53 transcriptional activity to regulate cell-cycle progression and apoptosis. We have identified a ubiquitin-specific peptidase, USP22, one of the 11 death-from-cancer signature genes that are critical in controlling cell growth and death, as a positive regulator of Sirt1. USP22 interacts with and stabilizes Sirt1 by removing polyubiquitin chains conjugated onto Sirt1. The USP22-mediated stabilization of Sirt1 leads to decreasing levels of p53 acetylation and suppression of p53-mediated functions. In contrast, depletion of endogenous USP22 by RNA interference destabilizes Sirt1, inhibits Sirt1-mediated deacetylation of p53 and elevates p53-dependent apoptosis. Genetic deletion of the usp22 gene results in Sirt1 instability, elevated p53 transcriptional activity and early embryonic lethality in mice. Our study elucidates a molecular mechanism in suppression of cell apoptosis by stabilizing Sirt1 in response to DNA damage and reveals a critical physiological function of USP22 in mouse embryonic development.

Vasohibin 2 is transcriptionally activated and promotes angiogenesis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) typically relies on angiogenesis for its malignant behavior, including growth and metastasis. Vasohibin 2 (VASH2) was previously identified as an angiogenic factor, but its role in tumorigenesis is unknown. Using quantitative PCR and western blot analyses, we found that VASH2 is overexpressed in HCC cells and tissues. Using chromatin immunoprecipitation, we detected histone modifications at the putative VASH2 promoter, with increased H3K4 trimethylation and H3 acetylation and decreased H3K27 trimethylation, suggesting that epigenetic mechanisms are responsible for the deregulated VASH2 transcription in HCC. Knockdown of VASH2 via siRNA inhibited the proliferation of the hepatoma cell lines by delaying cell cycle progression and increasing apoptosis. Importantly, we found VASH2 secreted in the culture supernatant, and co-expression of its secretory chaperone small vasohibin-binding protein (SVBP) further enhanced VASH2 secretion. The supernatant from HepG2 cells expressing VASH2 enhanced the proliferation, migration and tube formation of human umbilical vein endothelial cells, and knockdown of VASH2 significantly inhibited these effects. In an in vivo study using a nude mouse model, we found that exogenous VASH2 significantly contributed to tumor growth, microvessel density and hemoglobin concentration in the tumors. Further analyses showed that the VASH2-mediated increase in the transcription of fibroblast growth factor-2, vascular endothelial growth factor and vasohibin 1 may be the mechanism underlying these effects. Taken together, these data indicate that VASH2 is abnormally expressed in HCC cells as a result of histone modifications and that VASH2 contributes to the angiogenesis in HCC via an SVBP-mediated paracrine mechanism. These results indicate a novel and important role for VASH2 in HCC angiogenesis and malignant transformation.

Water-soluble noncovalently engineered graphene-neutral red nanocomposite with photocurrent generating capacity

We report a graphene-based nanocomposite prepared by noncovalently engineering reduced graphene oxide (rGO) with neutral red (NR). The water-soluble reduced graphene nanocomposite (rGO-NR) was well characterized by using X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), UV-vis spectroscopy, and 1HNMR spectroscopy; the results suggest a strong pi-pi interaction between the rGO and NR molecules. Fluorescence spectroscopy and electrochemistry studies indicate a direct electron transfer interaction among the graphene-NR hybrid, in which NR is electron donor and graphene is electron acceptor. The photocurrent generating property of this nanocomposite was confirmed from the photoelectrochemical measurements. The graphene-NR coated electrodes are capable of generating photocurrent under visible excitation. Such photocurrent generating nanocomposite provides potential application in optoelectronic devices.

Primary endometrial natural killer (NK)/T cell lymphoma: case report and review of literature

Primary natural killer (NK)/T cell lymphoma of the uterus is extremely rare. A case of primary NK/T cell lymphoma arising from the endometrium of the uterus was diagnosed by curettage which demonstrated the typical pathological characteristics of NK/T cell lymphoma. The patient received induction chemotherapy but refused hysterectomy. Later she developed bone marrow infiltration and eventually died on day 76 after diagnosis. The natural course of primary endometrial (NK)/T cell lymphoma was very aggressive. Conventional cytotoxic chemotherapy may be ineffective for this aggressive disease.

Incidence, diagnosis, and outcomes of vocal fold immobility after esophageal atresia (EA) and/or tracheoesophageal fistula (TEF) repair

BACKGROUND

The diagnosis of vocal fold paralysis in an infant is a devastating finding that may require a permanent tracheotomy. The incidence of congenital vocal fold paralysis is unknown, but it is thought to be more common in infants with anatomic anomalies in the aero-digestive system. Vocal fold paralysis after surgical repair of esophageal atresia and tracheoesophageal fistula is a rare finding often diagnosed after multiple failed extubations. Currently infants do not routinely undergo documentation of vocal fold motion prior to esophageal atresia repair. We report here on our experience with this rare complication.

METHOD

A retrospective review was done of patients with esophageal atresia and/or tracheoesophageal fistula from 1985 to 2009. Patient demographics, operative techniques, and outcomes were collected.

RESULTS

150 patients were identified. Mean age at surgical intervention was 12 ± 33 days. Otolaryngology service was consulted for 13% of patients with postoperative failure. Awake fiberoptic laryngoscopy identified 3% of patients with vocal fold paralysis. Bilateral vocal fold paralysis was found in 3 patients, and 2 patients had unilateral vocal fold paralysis. Patients with bilateral paralysis were treated with tracheotomy; unilateral paralysis was treated expectantly.

CONCLUSION

In this study, 3% of patients were diagnosed with vocal fold paralysis after esophageal atresia repair. The etiology of vocal fold paralysis in this study is difficult to assess. Pre-operative fiberoptic laryngoscopy is recommended to identify children with congenital vocal fold paralysis prior to surgical intervention, especially in those requiring revision surgery.

Analysis of properties and proinflammatory functions of cockroach allergens Per a 1.01s

Cockroaches have been identified as one of the major indoor allergens inducing perennial rhinitis and asthma. Per a 1s are a group of the major allergens from American cockroach. Although Per a 1s are major allergens from American cockroach, factors contributing to the allergenicity of Per a 1s are still poorly defined. To investigate the effects of Per a 1s on the expression of PARs and the release of proinflammatory cytokines from mast cells. Per a 1.0101 and Per a 1.0104 were cloned from American cockroach and then expressed in Eschericia coli. The purified allergens were used to stimulate P815 mast cells, and the expression of protease-activated receptors (PARs) was determined by real-time RT-PCR and flow cytometry. The levels of IL-4 and IL-13 in culture media were detected with ELISA. Sera from 80 and 77.3% of cockroach allergy patients reacted to recombinant Per a (rPer a) 1.0101 and rPer a 1.0104, confirming they are major allergens. Both rPer a 1.0101 and rPer a 1.0104 had no enzymatic activity, but rPer a 1.0101 upregulated the expression of PAR-1 and PAR-2, and rPer a 1.0104 enhanced the expression of PAR-1 and PAR-4 proteins. Both recombinant allergens were able to increase the release of IL-4 and IL-13 from P815 mast cells. This is the first study aiming to investigate functions of group 1 allergens of American cockroach. rPer a 1.0101 and rPer a 1.0104 have the capacity to upregulate the expression of PARs and to enhance Th2 cytokine production in mast cells.

Free-standing ZnO-CuO composite nanowire array films and their gas sensing properties

A modified hydrothermal method was developed to synthesize ZnO-CuO composite nanostructures. A free-standing film made of ZnO-CuO nanostructures was assembled on the surface of the hydrothermal solution with a smooth surface on one side and a spherical surface on the other side. The structure, growth mechanism and the optical properties of the composite nanostructures were studied. Structural characterizations indicate that the composite nanostructure mainly consisted of two single-crystal phases of CuO and ZnO. The sensitivity for CO gas detection was significantly improved for the composite CuO-ZnO nanostructure film. This method offers a possible route for the fabrication of free-standing nanostructure films of different functional composite oxides.

Human Angiostrongylus cantonensis: an update

Angiostrongylus cantonensis was first discovered in 1935 and has become an important emerging pathogen causing human angiostrongyliasis. Major outbreaks of human angiostrongyliasis have been reported in endemic regions. Thousands of cases of human angiostrongyliasis have been documented worldwide. A. cantonensis has spread from its traditional endemic regions of the Pacific islands and Southeast Asia to the American continent including the USA, Caribbean islands and Brazil. Humans acquire A. cantonensis by consumption of raw or undercooked intermediate snail hosts or paratenic hosts. The main clinical manifestations of human angiostrongyliasis are eosinophilic meningitis and ocular angiostrongyliasis. The treatment of this disease includes supportive treatment, corticosteroid therapy, and combined therapy with corticosteroids and anthelminthics. The most effective method for prevention is to persuade people not to eat raw or undercooked intermediate and paratenic hosts.