Reactivation of heat-inactivated Ku proteins by heat shock cognate protein HSC73

Purpose: Mouse double-stranded DNA-dependent protein kinase (DNA-PK) activity is heat sensitive. Recovery of heat-inactivated DNA repair activity is a problem after combination therapy with radiation and heat. We investigated the mechanism of recovery of heat-inactivated DNA-PK activity.

Methods: Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.

Results: The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37?°C after heat treatment at 44?°C for 15?min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3?h of incubation at 37?°C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3?h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.

Conclusions: These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72.     

Role of NK T cells in transplantation with particular emphasis on corneal transplantation

Natural killer T cells (NKT cells) are a unique subset of the immune system that possess characteristics of both an innate and adaptive immune response. This study reviews the reported roles of NKT cells in different solid transplantations such as cardiac, skin, liver, and corneal grafts as well as investigates a novel role of NKT cells in steroid-resistant corneal rejections. It is unknown why there is late corneal graft rejection despite being treated with immunosuppression. Our experimental data suggests NKT cells are playing a crucial part in steroid-resistant late graft rejections. While the pathophysiology of acute rejection is better understood, the process of chronic graft rejection is much less clear. Our data suggests NKT cells as a potential therapeutic target to prevent chronic transplant rejection which needs further investigation.     

Inhibition of miR-495-3p ameliorated sevoflurane induced damage through BDNF/ERK/CREB signaling pathways in HT22 cells

ObjectiveSevoflurane is used in anesthesia for surgery including in organ transplantation. We investigated the role of a non-coding single-stranded microRNA, miR-495-3p, in the sevoflurane-induced neurotoxicity using a mouse hippocampal neuronal cell line (HT22).MethodsThe levels of miR-495-3p in sevoflurane-exposed mice and HT22 cells were determined via RT-qPCR. The role of miR-495-3p on cell viability and apoptosis were determined by CCK-8 and flow cytometric assay, respectively. Western blotting was explored to measure levels of Bax, Bcl-2, active caspase 3, BDNF, p-ERK/ERK and p-CREB/CREB in HT22 cells. ELISA assay was used to examine the levels of reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione peroxidase (GPX) in cells. Dual luciferase reporter assay was used to explore the interaction of miR-495-3p and BDNF.ResultsThe level of miR-495-3p was increased sevoflurane-exposed mice and in sevoflurane-treated HT22 cells. Downregulation of miR-495-3p inhibited sevoflurane-induced apoptosis and promoted cell proliferation by upregulating the proteins of Bcl-2 and downregulating the expressions of Bax and active caspase-3 in HT22 cells. In addition, inhibition of miR-495-3p alleviated sevoflurane-induced oxidative injuries in HT22 cells via decline of ROS and upregulation of SOD and GPX. MiR-495-3p can inhibit the ERK/CREB pathway by targeting BDNF.ConclusionDownregulation of miR-495-3p can decrease oxidative status in HT22 cells and alleviate sevoflurane-induced cytotoxicity through stimulating the BDNF/ERK/CREB pathway.     

Overexpression of Ets-1 proto-oncogene in latent and clinical prostatic carcinomas

AIMS: The high incidence of clinically diagnosed prostatic cancer is exceeded by the frequency of tumours detected at autopsy. The Ets-1 proto-oncogene is expressed by a variety of malignant and normal tissues. Therefore, in this study, expression of Ets-1 protein was investigated in 'latent' prostatic cancer detected at autopsy, compared with benign prostatic hyperplasia, normal prostatic tissues and clinical prostatic cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed Ets-1 expression in 95 prostatic specimens including 19 cases of latent prostatic carcinoma (LPC) and 55 cases of clinical prostatic carcinoma (CPC), 11 cases of benign prostatic hyperplasia (BPH) and 10 cases of normal prostate (NP). Differences in the incidence of LPC and CPC suggest different courses for the biological progression of prostatic cancer. There was a significant difference in the degree of Ets-1 expression in CPC and LPC (P < 0.05). Ets-1 was not expressed in BPH and NP, but in malignant cases (57 of 74; 77.0%) commonly demonstrated immunoreactivity in the tumour cells. In our study the expression of Ets-1 between benign and malignant, and well, moderately and poorly differentiated adenocarcinomas of prostatic cancer showed significant differences. The presence of Ets-1 mRNA was confirmed by in-situ hybridization in human prostatic tissues. CONCLUSION: Our results suggest that Ets-1 might play an important role in carcinogenesis and/or the progression of human prostatic carcinomas.     

Loss of heterozygosity on chromosome 9q22.3 in microdissected basal cell carcinomas around the Semipalatinsk Nuclear Testing Site, Kazakhstan

A high incidence of skin cancers has been noted around the Semipalatinsk Nuclear Testing Site (SNTS) in Kazakhstan. Recently, basal cell carcinoma (BCC) susceptibility genes, human homolog of the Drosophila pathed gene (PTCH), and the xeroderma pigmentosa group A-complementing gene (XPA), have been cloned and localized on chromosome 9q22.3. To clarify the effect of low-dose irradiation on the occurrence of BCC, we used microdissection and polymerase chain reaction to identify loss of heterozygosity (LOH) at 9q22.3 using BCC samples obtained from this region. Ten Japanese samples were analyzed as controls. LOH with at least 1 marker was identified in 5 of 14 cases from around SNTS, whereas only 1 case with 1 marker was identified among the 10 Nagasaki cases. The total number of LOH alleles from SNTS (8 of 45) was significantly higher than the number from Nagasaki (1 of 26) (P = 0.03). The higher incidence of LOH on 9q22.3 in BCC from around SNTS suggests involvement of chronic low-dose irradiation by fallout from the test site as a factor in the cancers.     

Nuclear abnormalities in Pelger-Huet anomaly; progress in blood cell morphology

Gene abnormalities responsible for familial Pelger-Huet anomaly have been recently discovered. Abnormalities in sequence of Lamin B Receptor(LBR) gene results in a lack of LBR protein that is essential for chromatin-binding to nuclear membrane. In neutrophils lacking LBR protein shows abnormal bilobular or monolobular nuclear forms and hyper-condensed chromatin-aggregation. We re-analyzed distribution of such Pelger-Huet anomaly in other cell lineages; we found that not only neutrophils but erythroblasts, monocytes, lymphocytes, plasma cells, eosinophils and basophils are also carrying chromatin-hypercondensation. One third of megakaryocytes are also binucleated like neutrophils. We compared neutrophil morphology between familial Pelger-Huet anomaly and so called pseudo-Pelger-Huet anomaly observed in patients with myelodysplastic syndromes(MDS) and acute myeloid leukemia(AML). The neutrophils in MDS were much similar to those of the familial anomaly, but neutrophils of AML, such as t (8;21) M2-AML and t (15;17) M3-AML, showed more heterogeneous pattern in lobulation and chromatin-hypercondensation. Especially in M3, differentiation-induction by all-trans retinoic acid induced a marked neutrophilia with pseudo-Pelger-Huet anomaly without chromatin-hypercondensation. Lack of LBR protein in familial Pelger-Huet anomaly results in hypolobulation and chromatin-hypercondensation in neutrophils, but in other cells such as erythroblasts and lymphocytes only chromatin-hypercondensation can be observed. In contrast pseudo-Pelger-Huet anomaly are more heterogeneous in morphology compared to the familial anomaly. The lack of leukemic or MDS transformation in the familial anomaly is a sharp contrast to the neoplastic nature of the pseudo-Pelger-Huet anomaly. In conclusion, our morphological recognition of certain abnormality of cells shows an marked progression when genetic abnormality responsible for some of them are discovered, and often make us recognize a further heterogeneity in them. We, hematologists and technicians, must be well prepared to report our own observation of an un-explained morphological abnormality.     

Allogeneic hematopoietic stem cell transplantation provides sustained long-term survival for patients with adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a distinct peripheral T-cell neoplasm that is highly resistant to chemotherapy. Several groups, including ours, have reported encouraging results of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with ATLL. To confirm our previous report and to establish the basis for a phase II clinical study, we analyzed 40 allo-HSCT for acute and lymphoma types of ATLL in seven institutions in Japan between 1997 and 2002. All evaluable cases entered complete remission (CR) after allo-HSCT and the median survival time was 9.6 months for all patients. The estimated 3-year overall and relapse-free survival, and disease relapse were 45.3, 33.8 and 39.3%, respectively. Among 10 cases with ATLL relapse, five cases achieved CR again: three by the reduction or cessation of immunosuppressive agents, which suggested a graft-versus-ATLL (GvATLL) effect. However, univariate or multivariate analysis did not show any benefit of graft-versus-host disease (GVHD) on the prevention of relapse. These results suggested that allo-HSCT was effective for some patients with aggressive ATLL, and that the GvATLL effect could be achieved even without GVHD. A new phase II trial to test the efficacy of allo-HSCT for ATLL is warranted.     

Evaluation of the protective efficacy of four newly identified surface proteins of Erysipelothrix rhusiopathiae

Erysipelothrix rhusiopathiae is the causative agent of animal erysipelas and human erysipeloid. Bacterial surface proteins are promising vaccine candidates. We recently identified 3 E. rhusiopathiae surface proteins (GAPDH, HP0728, and HP1472) and characterized their roles as virulence factors. However, their efficacy as protective antigens is still unknown. The N-terminal region of a previously identified surface protein, CbpB (CbpB-N), is speculated to be a protective antigen, but this needs to be verified. The aim of this study was to evaluate the protective efficacy of GAPDH, HP0728, HP1472, and CbpB-N. Immunization with recombinant GAPDH provided complete protection in a mouse model, recombinant CbpB-N provided partial protection, while recombinant HP0728 and HP1472 provided no protection. Recombinant GAPDH also provided good protection in a pig model. GAPDH antiserum exhibited significant blood bactericidal activity against E. rhusiopathiae. In conclusion, GAPDH and CbpB-N were found to be protective antigens of E. rhusiopathiae, and GAPDH is a promising vaccine candidate.     

Measurement of oxidant and antioxidant levels in liver tissue obtained from patients with liver transplantation: A case-control study

ObjectiveThis study aimed to compare oxidant and antioxidant substance accumulation in the liver tissues of patients with chronic liver disease (recipients) who underwent liver transplantation (LT) with living liver donors (LLDs) who underwent living donor hepatectomy (LDH).MethodsThis prospective study included 160 recipients (LT group) and 40 LLDs (LLD group). During surgery, a piece of liver tissue measuring a minimum of 10 × 10 mm was obtained from the edge of the right lobe of the liver of recipients and LLDs, incubated for 10 min in saline to remove blood, and stored at −70 °C until biochemical analysis was performed. Catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), myeloperoxidase (MPO), prolidase, reduced glutathione (GSH), malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), total thiol, native thiol, and disulfide levels were measured in stored liver tissues.ResultsThere was a statistically significant difference between LT and LLD groups in terms of age (p < 0.001), body mass index (p = 0.019), GSH-Px (p < 0.001), SOD (p = 0.001), MPO (p < 0.001), prolidase (p < 0.001), GSH (p < 0.001), and MDA (p = 0.003) values in favor of the LT group. Furthermore, there was a statistically significant difference between LT and LLD groups in terms of CAT (p < 0.001), TAS (p < 0.001), TOS (p < 0.001), OSI (p < 0.001), total thiol (p < 0.001), native thiol (p < 0.001), and disulfide (p < 0.001) values in favor of the LLD group. There were no differences between the groups in terms of sex.ConclusionThis study demonstrated that it is possible to assess the extent of oxidative stress in liver tissues by measuring the levels of antioxidant enzymes, oxidants, or the end-products of oxidative stress. With the use of optimum and minimally invasive methods, quantifying these molecules will potentially help evaluate the extent of liver disease and prognostication of liver cirrhosis.