[Acute hypoxia blunts cold sensitivity through the inhibition of the lateral parabrachial nucleus in rats].

To explore the changes of cold sensitivity after exposure to acute hypoxia and its mechanisms, Sprague-Dawley rats were divided into normoxia control group (21% O2, 25 °C), 10% O2 hypoxia group (10% O2, 25 °C), 7% O2 hypoxia group (7% O2, 25 °C), normoxia cold group (21% O2, 10 °C) and hypoxia cold group (7% O2, 10 °C). Cold foot withdrawal latency and preference temperature of each group were measured, skin temperatures were estimated using an infrared thermographic imaging camera, body core temperature was recorded by wireless telemetry system, immunohistochemical staining was used to detect the expression of c-Fos in the lateral parabrachial nucleus (LPB). The results showed that acute hypoxia significantly prolonged the latency of cold foot withdrawal and significantly enhanced the intensity of cold stimulation for foot withdrawal, and the rats under hypoxia preferred cold temperature. Cold exposure (10 °C) for 1 h significantly enhanced the expression of c-Fos in LPB of rats in normoxia, while hypoxia inhibited cold-induced c-Fos expression. Acute hypoxia significantly increased the skin temperature of feet and tails, decreased the skin temperature of interscapular region, and decreased the body core temperature of rats. These results indicate that acute hypoxia can significantly blunt cold sensitivity through the inhibition of LPB, suggesting actively keeping warm measures should be taken at the early stage after ascent to high altitude to prevent the upper respiratory infection and acute mountain sickness.

Impact of treatment modality on long-term survival of stage IA small-cell lung cancer patients: a cohort study of the U.S. SEER database.

BACKGROUND: The optimal treatment modality for patients with stage IA (T1N0M0) small-cell lung cancer (SCLC) is still unclear. METHODS: Patients who received surgical resection or chemo-radiotherapy (CRT) between January 2004 and December 2014 were identified from The Surveillance, Epidemiology and End Results (SEER) database. Surgical resection included lobectomy, wedge resection, segmentectomy with lymphadenectomy [examined lymph node (ELN) ≥1]. Propensity score match analysis was utilized to balance the baseline characteristics. RESULTS: A total of 686 stage IA SCLC cases were included: 337 patients underwent surgery and 349 patients were treated by CRT alone. Surgery achieved a better outcome than CRT alone, with an adjusted hazard ratio (HR) of 0.495. Patients who underwent lobectomy demonstrated a longer overall survival (OS), compared to those who received sublobectomy (crude cohort, median OS, 69 vs. 38 months; match cohort, median OS, 67 vs. 38 months). Patients with ELN >7 presented with longer OS than those with ELN ≤7 (crude cohort, median OS, 91 vs. 49 months; matched cohort, median OS, 91 vs. 54 months). The additional efficacy of chemotherapy or radiotherapy in patients receiving lobectomy was observed. The best prognosis was achieved in the lobectomy plus CRT cohort, with a 5-year survival rate of 73.5%. CONCLUSIONS: The prolonged survival associated with lobectomy and chemotherapy or radiotherapy presents a viable treatment option in the management of patients with stage IA SCLC.

Preparation and Thermal Evaluation of Novel Polyimide Protective Coatings for Quartz Capillary Chromatographic Columns Operated over 320 °C for High-Temperature Gas Chromatography Analysis.

Protection of intrinsically brittle quartz chromatographic columns (CCs) from breakage or property deterioration in gas chromatography (GC) analysis has become an important research topic regarding high-temperature GC techniques. Polyimide (PI) has proved to be the most suitable protective coating for quartz CCs. In the current research, a series of novel high-temperature-resistant PI coatings for quartz CCs operated over 320 °C have been successfully prepared. For this purpose, the aromatic diamine with a rigid skeleton structure 2-(4-aminophenyl)-5-aminobenzimidazole (APBI) was copolymerized with two aromatic dianhydrides-3,3',4,4'-benzophenotetracarboxylic acid dianhydride (BTDA) and 4,4'-oxydiphthalic anhydride (ODPA)-and an aromatic diamine with flexible ether linkages-4,4'-oxydianiline (ODA)-by a two-step polymerization procedure via soluble poly(amic acid) (PAA) precursors, followed by thermal imidization at elevated temperatures. The developed PI coatings exhibited good comprehensive properties, including glass transition temperatures (Tg) as high as 346.9 °C, measured by dynamic mechanical analysis (DMA), and coefficients of linear thermal expansion (CTEs) as low as 24.6 × 10-6/K in the range of 50-300 °C. In addition, the PI coatings exhibited good adhesion to the fused quartz capillary columns. No cracking, delamination, warpage, or other failures occurred during the 100-cycle thermal shock test in the range of 25-320 °C.

Small-molecule targeting of brachyury transcription factor addiction in chordoma.

Chordoma is a primary bone cancer with no approved therapy1. The identification of therapeutic targets in this disease has been challenging due to the infrequent occurrence of clinically actionable somatic mutations in chordoma tumors2,3. Here we describe the discovery of therapeutically targetable chordoma dependencies via genome-scale CRISPR-Cas9 screening and focused small-molecule sensitivity profiling. These systematic approaches reveal that the developmental transcription factor T (brachyury; TBXT) is the top selectively essential gene in chordoma, and that transcriptional cyclin-dependent kinase (CDK) inhibitors targeting CDK7/12/13 and CDK9 potently suppress chordoma cell proliferation. In other cancer types, transcriptional CDK inhibitors have been observed to downregulate highly expressed, enhancer-associated oncogenic transcription factors4,5. In chordoma, we find that T is associated with a 1.5-Mb region containing 'super-enhancers' and is the most highly expressed super-enhancer-associated transcription factor. Notably, transcriptional CDK inhibition leads to preferential and concentration-dependent downregulation of cellular brachyury protein levels in all models tested. In vivo, CDK7/12/13-inhibitor treatment substantially reduces tumor growth. Together, these data demonstrate small-molecule targeting of brachyury transcription factor addiction in chordoma, identify a mechanism of T gene regulation that underlies this therapeutic strategy, and provide a blueprint for applying systematic genetic and chemical screening approaches to discover vulnerabilities in genomically quiet cancers.

Aggressive surgical resection does not improve survival in operable esophageal squamous cell carcinoma with N2-3 status.

AIM: To investigate the influence of nodal status on response and clarify the optimal treatment for operable esophageal squamous cell carcinoma (OSCC). METHODS: We retrospectively analyzed 1490 OSCC patients who underwent transthoracic esophagectomy and lymphadenectomy between December 1996 and December 2009 at the Sun Yat-sen University Cancer Center. The surgical approach and the number of resected lymph nodes (LNs) were considered in the assessment of surgery. Patients were classified according to their nodal statuses (N0 vs N1 vs N2-3). Overall survival was defined as the time from the date of death or final follow-up. Survival analysis was performed using the Kaplan-Meier method and differences between curves were assessed by the log-rank test. Univariate and multivariate Cox regression analyses were used to identify factors associated with prognosis. Statistical significance was assumed at a P < 0.05. RESULTS: With a median time from surgery to the last censoring date for the entire cohort of 72.2 mo, a total of 631 patients were still alive at the last follow-up and the median survival time was 35.5 mo. The surgical approach (left transthoracic vs Ivor-Lewis/tri-incisional) was verified as independent prognostic significance in patients with N0 or N1 status, but not in those with N2-3 status. Similar results were also observed with the number of resected LNs (≤ 14 vs ≥ 15). Compared with surgery alone, combined therapy achieved better outcomes in patients with N1 or N2-3 status, but not in those with N0 status. For those with N2-3 status, neither the surgical approach nor the number of resected LNs reached significance by univariate analysis, with unadjusted HRs of 0.826 (95%CI: 0.644-1.058) and 0.849 (95%CI: 0.668-1.078), respectively, and aggressiveness of surgery did not influence the outcome; the longest survival was observed in those patients who received the combined therapy. CONCLUSION: Combined therapy has a positive role in OSCC with LN metastasis, and aggressive surgical resection does not improve survival in patients with N2-3 status.

Decreased mRNA expression of transcription factor forkhead box F2 is an indicator of poor prognosis in patients with resected esophageal squamous cell carcinoma.

The transcription factor forkhead box F2 (FOXF2) is an evolutionarily conserved DNA-binding protein involved in embryogenesis and metabolism. Although recent studies prove that FOXF2 is a tumor suppressor in various human cancers, the role of FOXF2 in esophageal squamous cell carcinoma (ESCC) remains unknown. Therefore, samples were collected from 188 ESCC patients, including 33 pairs of tumor and non-tumor tissues, and FOXF2 mRNA expression was investigated by quantitative polymerase chain reaction. The results demonstrated that FOXF2 mRNA is downregulated in tumor tissues compared to paired non-tumor tissues (P=0.048). The receiver operating characteristic curve analysis indicated 1.2 as a cut-off point and, thus, 125 and 63 tumors were classified as low- and high-level FOXF2 mRNA expression, respectively. We observed that low-level FOXF2 mRNA expression in the tumors was associated with a higher frequency of lymph node metastasis (P=0.044), an effect further suggested by the multivariate logistic regression analysis (P=0.060). According to the univariate Cox analysis, patients harboring tumors with low-level FOXF2 mRNA expression had a significantly increased mortality risk compared to those with high-level expression (hazard ratio=1.700, 95% confidence interval, 1.077-2.681), with 5-year survival rates of 41.1 and 61.9%, respectively. This negative prognostic effect of low-level FOXF2 mRNA expression was further validated in the multivariate Cox analysis (P=0.021). The subgroup analysis demonstrated that the effect of FOX2 mRNA expression was limited to male patients and those with advanced-stage disease. Taken together, these findings suggest that FOXF2 may be an anti-oncogene for ESCC and decreased FOXF2 mRNA expression is associated with a poor prognosis in patients with ESCC.

Clinicopathological analysis of 155 patients with persistent isolated hematuria.

OBJECTIVES: To reveal etiologies of persistent isolated hematuria (PIH) through ultrastructural pathological examination, to disclose clinicopathological correlation in cases with PIH, and to summarize appropriate management of patients with PIH. METHODS: we retrospectively studied 155 PIH patients receiving renal biopsy between January, 2003 and December, 2008 in Peking Union Medical College Hospital. All the clinical data and follow-up result were analyzed. RESULTS: All subjects included 38 children and 117 adults, with mean age of 11.38±3.25 years for children and 35.17±8.44 years for adults. Thin basement membrane nephropathy (TBMN) was the most common pathology (55.3% of children and 49.6% of adults), followed by IgA nephropathy (18.4% of children and 32.5% of adults, mainly grade 2-3) and mesangial proliferative glomerulonephritis (MsPGN) without IgA deposition (13.2% of children and 12.8% of adults). Besides, Alport syndrome (2.6% of children) and membrane nephropathy (2.6% of children and 0.9% of adults) were demonstrated as other causes of PIH. Elevated mean arteral pressure or protein excretion rate, as well as episodic macrohematuria, indicated higher risk for MsPGN rather than TBMN. On the other hand, severity of microhematuria was irrelevant to pathological types of PIH. Totally, 86 patients were followed up and 37 cases therein stayed on track for long term (mean duration 41.11?28.92 months, range 8-113 months). Most cases had benign clinical course except 3 cases with TBMN, 5 cases with IgA nephropathy, 1 case with MsPGN (without IgA deposition), and 1 case with Alport syndrome, who developed hypertension or proteinuria. All of them were administered timely intervention. CONCLUSIONS: Close follow-up should be required as the primary management for PIH. Equally important is careful monitoring for early identification of undesirable predictors; while renal biopsy and other timely intervention are warranted if there is hypertension, significant proteinuria or renal impairment.

Video-assisted thoracoscopic surgery (VATS) right upper lobectomy and systematic lymph node dissection for lung cancer.

Video-assisted thoracoscopic surgery (VATS) represents a new trend in the development of minimally invasive thoracic surgery. When applied in lung cancer surgeries, VATS can be used for both pulmonary lobectomy and regional lymph node dissection. Currently the main concerns are focused on the completeness of lymph node dissection for lung cancer and the safety of surgery. The lymph node dissection includes two parts: (I) dissection of interlobar and hilar lymph nodes; and (II) dissection of mediastinal lymph nodes. The demonstrated surgical procedures are featured by: (I) the interlobar and hilar lymph nodes are not removed separately; rathr, they are taken out en bloc with the pulmonary lobes during the surgery; and (II) systematic lymph node dissection, instead of systematic sampling, is applied for the removal of mediastinal lymph nodes. Also, during the fully anatomical resection, each blood vessel and bronchus underwent anatomical dissociation, indicating that this surgery is safe.

High expression of transient potential receptor C6 correlated with poor prognosis in patients with esophageal squamous cell carcinoma.

TRPC6 plays a crucial role in the tumor progression of various cancers. The relation between the expression of TRPC6 and clinical prognosis has not been studied yet. Our study was to elucidate the role of TRPC6 in predicting outcomes of patients with esophageal squamous cell carcinoma (ESCC). Fresh frozen samples were collected immediately from 172 patients with ESCC after surgical resection from 2003 to 2008 at Sun Yat-sen University Cancer Center, including 45 pairs of tumor tissues and nontumor tissues. TRPC6 expression was measured by quantitative real-time PCR and Western blotting analyses. TRPC6 mRNA and protein were up-regulated in ESCC tissues when compared with the paired nontumor tissues. High expression of TRPC6 mRNA was associated with the higher pT status (P = 0.016) and pathological staging (P = 0.040). The 5-year disease-specific survival in the high expression of TRPC6 mRNA group (>188.98, n = 81) is poorer than that in low-level expression group (≤188.98, n = 91) (42.1 vs. 62.7 %, P = 0.004). Stratified analysis according to the pathological stage revealed its discernibility on DSS was only pronounced in patients with pStage III (P = 0.015). Cox multivariate analysis revealed that pN category (P < 0.001; Relative risk, 2.897, 95 % CI 1.830-4.585) and the expression of TRPC6 mRNA (P = 0.006; Relative risk, 1.863, 95 % CI 1.196-2.902) were independent prognostic factors. TRPC6 mRNA overexpression correlated with poor prognosis in patients with ESCC and might serve as a novel prognostic biomarker for resected ESCC patients in advanced stage.

Correlation of p53 status with the response to chemotherapy-based treatment in esophageal cancer: a meta-analysis.

BACKGROUND: The value of p53 status for predicting response to chemotherapy-based treatment in patients with esophageal cancer has been controversial. We conducted a meta-analysis to elucidate the correlation of p53 status with the response to chemotherapy-based treatment. METHODS: Studies were searched in PubMed, Embase, and Web of Science (up to September 2012). The p53 status and response to therapy were defined and standardized. Subgroup analyses based on the treatment and histopathology were performed to explore the usefulness of p53 status for predicting response to therapy in esophageal cancer. Sensitivity analyses were conducted by removing specific studies to assess the effects of study quality. RESULTS: We included 28 studies with 1497 cases in our meta-analysis. Wild-type form of p53 status (low expression of p53 protein and/or wild-type p53 gene) was associated with high response to chemotherapy-based treatment in esophageal cancer (total major response [MR]: risk ratio [RR] = 1.09, 95 % CI = 1.03-1.16, P = .003; pathological MR: RR = 1.15, 95 % CI = 1.06-1.25, P = .001; total complete response [CR]: RR = 1.08, 95 % CI = 1.00-1.17, P = .040). The similar correlation between the wild-type form p53 and response to therapy were also detected in subgroup analyses (total MR, pathological MR, and total CR in chemoradiotherapy subgroup; total MR in chemotherapy subgroup; total MR and pathological CR in esophageal squamous cell carcinoma [ESCC]). Additionally, patients with wild-type form p53 status had high pathological complete response rate to neoadjuvant chemoradiotherapy in ESCC. CONCLUSIONS: The current meta-analysis suggested that p53 status might be a predictive biomarker for response to chemotherapy-based treatment in esophageal cancer.

Cost-effective framework for basic surgical skills training.

BACKGROUND: The importance of basic surgical skills is entirely agreed among surgical educators. However, restricted by ethical issues, finance etc, the basic surgical skills training is increasingly challenged. Increasing cost gives an impetus to the development of cost-effective training models to meet the trainees' acquisition of basic surgical skills. In this situation, a cost-effective training framework was formed in our department and introduced here. METHODS: Each five students were assigned to a 'training unit'. The training was implemented weekly for 18 weeks. The framework consisted of an early, a transitional, an integrative stage and a surgical skills competition. Corresponding training modules were selected and assembled scientifically at each stage. The modules comprised campus intranet databases, sponge benchtop, nonliving animal tissue, local dissection specimens and simulating reality operations. The training outcomes used direct observation of procedural skills as an assessment tool. The training data of 50 trainees who were randomly selected in each year from 2006 to 2011 year, were retrospectively analysed. RESULTS: An excellent and good rate of the surgical skills is from 82 to 88%, but there is no significant difference among 6 years (P > 0.05). The skills scores of the contestants are markedly higher than those of non-contestants (P < 0.05). The average training cost per trainee is about $21.85-34.08. CONCLUSION: The present training framework is reliable, feasible, repeatable and cost-effective. The skills competition can promote to improve the surgical skills level of trainees.

Genetic inactivation of the adenosine A(2A) receptor exacerbates brain damage in mice with experimental autoimmune encephalomyelitis.

Studies with multiple sclerosis patients and animal models of experimental autoimmune encephalomyelitis (EAE) implicate adenosine and adenosine receptors in modulation of neuroinflammation and brain injury. Although the involvement of the A(1) receptor has been recently demonstrated, the role of the adenosine A(2A) receptor (A(2A)R) in development of EAE pathology is largely unknown. Using mice with genetic inactivation of the A(2A) receptor, we provide direct evidence that loss of the A(2A)R exacerbates EAE pathology in mice. Compared with wild-type mice, A(2A)R knockout mice injected with myelin oligodendroglia glycoprotein peptide had a higher incidence of EAE and exhibited higher neurological deficit scores and greater decrease in body weight. A(2A)R knockout mice displayed increased inflammatory cell infiltration and enhanced microglial cell activation in cortex, brainstem, and spinal cord. In addition, demyelination and axonal damage in brainstem were exacerbated, levels of Th1 cytokines increased, and Th2 cytokines decreased. Collectively, these findings suggest that extracellular adenosine acting at A(2A)Rs triggers an important neuroprotective mechanism. Thus, the A(2A) receptor is a potential target for therapeutic approaches to multiple sclerosis.

The antioxidant effects of garlic saponins protect PC12 cells from hypoxia-induced damage.

Hypoxia frequently occurs under several different cellular circumstances. Excess reactive oxygen species that are induced by hypoxia may result in cell injury and dysfunction. Recently, garlic has been found to possess some biological and pharmacological activities. The present study examined the effects of garlic saponins (GSP) on the survival of differentiated PC12 (dPC12) cells and the oxidative-antioxidant system. dPC12 cells were exposed to 2 % O2 in order to establish a neuronal insult model. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay and lactate dehydrogenase (LDH) release assay. The expression of selected genes (catalase (CAT), p65 and neuron-specific class III ß-tubulin) was evaluated by real-time PCR and immunoblot assays. CAT activity, malondialdehyde (MDA) and 8-hydroxy-deoxyguanosine (8-OH-dG) concentrations were also determined. The data showed that hypoxia dramatically damaged dPC12 cells, while treatment with approximately 5 × 10- 2-10 ng/ml GSP improved cell viability, decreased LDH leakage and caused the cells to maintain neuronal-like characteristics in hypoxia. The production of MDA and 8-OH-dG was attenuated by GSP. CAT activity in dPC12 cells pretreated with GSP was higher than that of the hypoxic control. Moreover, GSP up-regulated CAT expression and decreased the total protein expression as well as the nuclear expression of p65 in hypoxic cells. These data indicate that GSP has antioxidant properties that can protect dPC12 cells from hypoxia-induced damage, which may be related to the up-regulation of CAT expression and activity as well as a decrease in the expression and nucleus distribution of p65 through effects on redox-sensitive signalling pathways.

Regulation of bone marrow hematopoietic stem cell is involved in high-altitude erythrocytosis.

OBJECTIVE: Hypoxia at high altitudes can lead to increased production of red blood cells through the hormone erythropoietin (EPO). In this study, we observed how the EPO-unresponsive hematopoietic stem cell (HSC) compartment responds to high-altitude hypoxic environments and contributes to erythropoiesis. MATERIALS AND METHODS: Using a mouse model at simulated high altitude, the bone marrow (BM) and spleen lineage marker(-)Sca-1(+)c-Kit(+) (LSK) HSC compartment were observed in detail. Normal LSK cells were then cultured under different conditions (varying EPO levels, oxygen concentrations, and BM supernatants) to investigate the causes of the HSC responses. RESULTS: Hypoxic mice exhibited a marked expansion in BM and spleen LSK compartments, which were associated with enhanced proliferation. BM HSCs seemed to play a more important role in erythropoiesis at high altitude than spleen HSCs. There was also a lineage fate change of BM HSCs in hypoxic mice that was manifested in increased megakaryocyte-erythrocyte progenitors and periodically reduced granulocyte-macrophage progenitors in the BM. The LSK cells in hypoxic mice displayed upregulated erythroid-specific GATA-1 and downregulated granulocyte-macrophage-specific PU.1 messenger RNA expression, as well as the capacity to differentiate into more erythroid precursors after culture. BM culture supernatant from hypoxic mice (but not elevated EPO or varying O(2) tension) could induce expansion and erythroid-priority differentiation of the HSC population, a phenomenon partially caused by increasing interleukin-3 and interleukin-6 secretion in the BM. CONCLUSIONS: The present study suggests a new EPO-independent HSC mechanism of high-altitude erythrocytosis.

Hypoxic training increases metabolic enzyme activity and composition of alpha-myosin heavy chain isoform in rat ventricular myocardium.

Cardiac muscle adaptation is essential for maintaining physical capacity after ascending to high altitude. This study examines the effects of high altitude training on myocardial metabolic enzyme activity and composition of alpha-myosin heavy chain (MHC). Rats were randomly divided into normobaric sedentary (NS) and training (NT) groups, and hypobaric sedentary (HS) and training (HT) groups. HS and HT rats were exposed to hypobaric hypoxia (simulated 4,000-5,000 m) for 5 weeks (24 h/day), and HT rats simultaneously received swim training. Hypoxia exposure for 5 weeks led to a decrease in succinate dehydrogenase (SDH) and citrate synthase (CS) activities in the left ventricle (LV), and a decrease in CS, hexokinase (HK) and total lactate dehydrogenase (LDH) activities in the right ventricle (RV) (p < 0.05, HS vs. NS). Furthermore, 1 h/day swim training during hypoxia exposure enhanced the CS activity in LV and the SDH and CS activities in RV (p < 0.05, HT vs. HS). The percentages of alpha-MHC in both ventricles in HT were higher than those in HS (p < 0.05). We conclude that exercise training at high altitude is beneficial for cardiac muscle adaptation to hypoxia by increasing activities of enzymes and percentage of alpha-MHC. This may contribute to improved cardiac function and work capacity at high altitude.

p300 expression is induced by oxygen deficiency and protects neuron cells from damage.

Low oxygen level or oxygen deficiency (hypoxia) is a major factor causing neuronal damage in many diseases. Inducing cell adaptation to hypoxia is an effective method for neuroprotection that can be achieved by either inhibiting the death effectors or enhancing the survival factors. Transcription coactivator p300 is necessary for hypoxia-induced transcriptional activation and plays an important role in neuron survival. However, the alteration of p300 expression under hypoxia condition and its role in hypoxia-induced neuronal damage remain unclear. In this study, the distribution of p300 in rat brain and the alteration of its expression in rat hippocampus during hypobaric hypoxia exposure were detected. In addition, the role of p300 in neuronal-like PC12 cell damage induced by oxygen deficiency (3% oxygen) was evaluated. Our results showed that p300 protein was mainly expressed in the cells expressed beta-tubulin III in the cerebral cortex, hippocampus, cerebellum cortex, medulla oblongata and hypothalamus. Less or no positive signal of p300 expression was observed in beta-tubulin III negative cells. This indicated that p300 was predominantly expressed in neurons of rat brain. Furthermore, p300 expression was up-regulated in rat hippocampus during hypoxia exposure and in neuronal-like PC12 cells under 3% oxygen condition. Interestingly, neuronal-like PC12 cell damage induced by oxygen deficiency (3% oxygen) was increased by suppression of p300 expression with short hairpin RNA (shRNA). These data indicate that p300 is an important molecule for neuroprotection under hypoxia.

CoCl2-induced expression of p300 promotes neuronal-like PC12 cell damage.

Hypoxia inducible factor-1 (HIF-1) is an important transcription activator involved in cell responses to hypoxic stress. Previous studies demonstrated that HIF-1 exerts both pro- and anti-survival effects under hypoxia. The mechanisms underlying these contrary effects of HIF-1 remain unclear. Transcription co-activator p300 is necessary for HIF-1-induced transcriptional activation. Many factors inhibit HIF-1 activity by competitively binding to p300, which suggests that p300 is a key player in the modulation of HIF-1 function. To examine the alteration of p300 expression under hypoxia and its role in hypoxia-induced neuronal damage, neuronal-like PC12 cells were cultured with cobalt chloride (CoCl2), a hypoxia mimic reagent. The results showed that CoCl2 treatment-induced p300 expression along with an increase in cell damage. Furthermore, CoCl2-induced cell damage was attenuated by suppression of p300 expression with short hairpin RNA (shRNA). The data suggests that CoCl2-induced up-regulation of p300 expression promotes neuronal-like PC12 cell damage.

A critical role of the adenosine A2A receptor in extrastriatal neurons in modulating psychomotor activity as revealed by opposite phenotypes of striatum and forebrain A2A receptor knock-outs.

The function of striatal adenosine A(2A) receptors (A(2A)Rs) is well recognized because of their high expression levels and the documented antagonistic interaction between A(2A)Rs and dopamine D(2) receptors in the striatum. However, the role of extrastriatal A(2A)Rs in modulating psychomotor activity is largely unexplored because of the low level of expression and lack of tools to distinguish A(2A)Rs in intrinsic striatal versus nonstriatal neurons. Here, we provided direct evidence for the critical role of A(2A)Rs in extrastriatal neurons in modulating psychomotor behavior using newly developed striatum-specific A(2A)R knock-out (st-A(2A)R KO) mice in comparison with forebrain-specific A(2A)R KO (fb-A(2A)R KO) mice. In contrast to fb-A(2A)R KO (deleting A(2A)Rs in the neurons of striatum as well as cerebral cortex and hippocampus), st-A(2A)R KO mice exhibited Cre-mediated selective deletion of the A(2A)R gene, mRNA, and proteins in the neurons (but not astrocytes and microglial cells) of the striatum only. Strikingly, cocaine- and phencyclidine-induced psychomotor activities were enhanced in st-A(2A)R KO but attenuated in fb-A(2A)R KO mice. Furthermore, selective inactivation of the A(2A)Rs in extrastriatal cells by administering the A(2A)R antagonist KW6002 into st-A(2A)R KO mice attenuated cocaine effects, whereas KW6002 administration into wild-type mice enhanced cocaine effects. These results identify a critical role of A(2A)Rs in extrastriatal neurons in providing a prominent excitatory effect on psychomotor activity. These results indicate that A(2A)Rs in striatal and extrastriatal neurons exert an opposing modulation of psychostimulant effects and provide the first direct demonstration of a predominant facilitatory role of extrastriatal A(2A)Rs.

Adenosine A2A receptor antagonists exert motor and neuroprotective effects by distinct cellular mechanisms.

OBJECTIVE: To investigate whether the motor and neuroprotective effects of adenosine A(2A) receptor (A(2A)R) antagonists are mediated by distinct cell types in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson's disease. METHODS: We used the forebrain A(2A)R knock-out mice coupled with flow cytometric analyses and intracerebroventricular injection to determine the contribution of A(2A)Rs in forebrain neurons and glial cells to A(2A)R antagonist-mediated motor and neuroprotective effects. RESULTS: The selective deletion of A(2A)Rs in forebrain neurons abolished the motor stimulant effects of the A(2A)R antagonist KW-6002 but did not affect acute MPTP neurotoxicity. Intracerebroventricular administration of KW-6002 into forebrain A(2A)R knock-out mice reinstated protection against acute MPTP-induced dopaminergic neurotoxicity and attenuated MPTP-induced striatal microglial and astroglial activation. INTERPRETATION: A(2A)R activity in forebrain neurons is critical to the control of motor activity, whereas brain cells other than forebrain neurons (likely glial cells) are important components for protection against acute MPTP toxicity.

Mutant SOD1G93A in bone marrow-derived cells exacerbates 3-nitropropionic acid induced striatal damage in mice.

3-Nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase, produces selective lesions in striatal neurons that resemble those observed in Huntington's disease neuropathology. In this study, we evaluated the role of peripheral bone marrow-derived cells (BMDCs) in the 3-NP-induced striatal damage by transplanting bone marrow cells with human SOD1 G93A mutation (mSOD1(G93A)) which induces amyotrophic lateral sclerosis through an unknown gain of toxicity and mitochondrial dysfunction. We assessed striatal damage after 3-NP treatment in the recipient C57BL/6 wild-type (WT) mice that received bone marrow cells from WT or mSOD1(G93A) transgenic donor mice (WT-->WT or mSOD(G93A)-->WT). After intraperitoneal injection of 3-NP, six of the eight mSOD1(G93A)-->WT mice had bilateral striatal lesions while only one out of eight WT-->WT mice had a striatal lesion. The lesion volume was significantly higher in the mSOD1(G93A)-->WT mice than in the WT-->WT mice. However, following an intrastriatal injection of 3-NP, there was no significant difference in the lesion volumes between the WT-->WT mice and mSOD1(G93A)-->WT mice. Thus, the exacerbation of 3-NP-induced striatal damage in mSOD(G93A)-->WT mice was only seen after systemic administration of 3-NP, but not after intrastriatal injection. These results demonstrate that altered SOD1 activity (mSOD(G93A)) in BMDCs affects striatal damage probably through a mechanism involving a systemic factor.