Analysis of brain structural covariance network in Cushing disease.

Background: Cushing disease (CD) is a rare clinical neuroendocrine disease. CD is characterized by abnormal hypercortisolism induced by a pituitary adenoma with the secretion of adrenocorticotropic hormone. Individuals with CD usually exhibit atrophy of gray matter volume. However, little is known about the alterations in topographical organization of individuals with CD. This study aimed to investigate the structural covariance networks of individuals with CD based on the gray matter volume using graph theory analysis. Methods: High-resolution T1-weighted images of 61 individuals with CD and 53 healthy controls were obtained. Gray matter volume was estimated and the structural covariance network was analyzed using graph theory. Network properties such as hubs of all participants were calculated based on degree centrality. Results: No significant differences were observed between individuals with CD and healthy controls in terms of age, gender, and education level. The small-world features were conserved in individuals with CD but were higher than those in healthy controls. The individuals with CD showed higher global efficiency and modularity, suggesting higher integration and segregation as compared to healthy controls. The hub nodes of the individuals with CD were Short insular gyri (G_insular_short_L), Anterior part of the cingulate gyrus and sulcus (G_and_S_cingul-Ant_R), and Superior frontal gyrus (G_front_sup_R). Conclusions: Significant differences in the structural covariance network of patients with CD were found based on graph theory. These findings might help understanding the pathogenesis of individuals with CD and provide insight into the pathogenesis of this CD.

Imaging cerebral microbleeds in Cushing's disease evaluated by quantitative susceptibility mapping: an observational cross-sectional study.

DESIGN: Cushing's disease (CD) is a rare clinical syndrome characterized by chronic exposure to hypercortisolism due to an adrenocorticotropic hormone-secreting pituitary adenoma. The adverse effects of chronic exposure to hypercortisolism on the human brain remain unclear. The purpose of this study was to assess the prevalence of cerebral microbleeds (CMBs) in CD patients and their associations with clinical characteristics. METHODS: In this study, 48 active CD patients, 39 remitted CD patients, and 52 healthy control (HC) subjects underwent MRI. CD patients also underwent neuropsychological testing and clinical examinations. The number, locations, and volumes of CMBs were assessed on quantitative susceptibility mapping (QSM) images and with the Microbleed Anatomical Rating Scale. The correlation between CMBs and clinical characteristics was explored. RESULTS: The prevalence of CMBs among active and remitted CD patients was higher than that among HCs (16.3%, 20.5%, and 3.3%, respectively). Moreover, the age of CD patients with CMBs were much younger than HCs with CMBs. Furthermore, the increased number of CMBs in active CD patients was associated with increased cerebrospinal fluid (CSF) volumes in remitted CD patients. CONCLUSIONS: Chronic exposure to hypercortisolism may be relevant to CMBs and significantly correlated with altered brain volumes in CD.

Disruption of Rich-Club Connectivity in Cushing Disease.

OBJECTIVE: Cushing disease (CD) is a rare clinical disease in which brain structural and function are impaired as the result of excessive cortisol. However, little is known whether rich-club organization changes in patients with CD, as visualized on resting-state magnetic resonance imaging (fMRI), can reverse to normal conditions after transsphenoidal surgery (TSS). In this study, we aimed to investigate whether the functional connectivity of rich-club organization is affected and whether any abnormal changes may reverse after TSS. METHODS: In this study, 38 patients with active CD, 33 with patients with CD in remission, and 41 age-, sex-, and education-matched healthy control participants underwent resting-state fMRI. Brain functional connectivity was constructed based on fMRI and rich club was calculated with graph theory approach. We constructed the functional brain networks for all participants and calculated rich-club connectivity based on fMRI. RESULTS: We identified left precuneus, right precuneus, left middle cingulum, right middle cingulum, right inferior temporal, right middle temporal, right lingual, right postcentral, right middle occipital, and right precentral regions as rich club nodes. Compared with healthy control participants, rich-club connectivity was significantly lower in patients with active CD (P < 0.001). Moreover, abnormal rich-club connectivity improved to normal after TSS. CONCLUSIONS: Our results show rich-club organization was disrupted in patients with active CD with excessive cortisol production. TSS can reverse abnormal rich-club connectivity. Rich club may be a new indicator to investigate the outcomes of TSS and to increase our understanding of the effect of excessive cortisol on brain functional connectivity in patients with CD.

The therapeutic value of XL388 in human glioma cells.

XL388 is a highly efficient and orally-available ATP-competitive PI3K-mTOR dual inhibitor. Its activity against glioma cells was studied here. In established and primary human glioma cells, XL388 potently inhibited cell survival and proliferation as well as cell migration, invasion and cell cycle progression. The dual inhibitor induced significant apoptosis activation in glioma cells. In A172 cells and primary human glioma cells, XL388 inhibited Akt-mTORC1/2 activation by blocking phosphorylation of Akt and S6K1. XL388-induced glioma cell death was only partially attenuated by a constitutively-active mutant Akt1. Furthermore, it was cytotoxic against Akt1-knockout A172 glioma cells. XL388 downregulated MAF bZIP transcription factor G (MAFG) and inhibited Nrf2 signaling, causing oxidative injury in glioma cells. Conversely, antioxidants, n-acetylcysteine, pyrrolidine dithiocarbamate and AGI-106, alleviated XL388-induced cytotoxicity and apoptosis in glioma cells. Oral administration of XL388 inhibited subcutaneous A172 xenograft growth in severe combined immunodeficient mice. Akt-S6K1 inhibition and MAFG downregulation were detected in XL388-treated A172 xenograft tissues. Collectively, XL388 efficiently inhibits human glioma cell growth, through Akt-mTOR-dependent and -independent mechanisms.

Effects of New York's Executive Order on Face Mask Use on COVID-19 Infections and Mortality: A Modeling Study

BackgroundNew York City (NYC) was the epicenter of the COVID-19 pandemic in the United States. On April 17, 2020, the State of New York implemented an Executive Order that requires all people in New York to wear a face mask or covering in public settings where social distancing cannot be maintained. It is unclear how this Executive Order has affected the spread of COVID-19 in NYC. MethodsA dynamic compartmental model of COVID-19 transmission among NYC residents was developed to assess the effect of the Executive Order on face mask use on infections and deaths due to COVID-19 in NYC. Data on daily and cumulative COVID-19 infections and deaths were obtained from the NYC Department of Health and Mental Hygiene. ResultsThe Executive Order on face mask use is estimated to avert 99,517 (95% CIs: 72,723-126,312) COVID-19 infections and 7,978 (5,692-10,265) deaths in NYC. If the Executive Order was implemented one week earlier (on April 10), the averted infections and deaths would be 111,475 (81,593-141,356) and 9,017 (6,446-11,589), respectively. If the Executive Order was implemented two weeks earlier (on April 3 when the Centers for Disease Control and Prevention recommended face mask use), the averted infections and deaths would be 128,598 (94,373-162,824) and 10,515 (7,540-13,489), respectively. ConclusionsNew Yorks Executive Order on face mask use is projected to have significantly reduced the spread of COVID-19 in NYC. Implementing the Executive Order at an earlier date would avert even more COVID-19 infections and deaths.

Cardiovascular disease and severe hypoxemia associated with higher rates of non-invasive respiratory support failure in COVID-19

RationaleAcute hypoxemic respiratory failure (AHRF) is the major complication of coronavirus disease 2019 (COVID-19), yet optimal respiratory support strategies are uncertain. ObjectivesTo describe outcomes with high-flow oxygen delivered through nasal cannula (HFNC) and non-invasive positive pressure ventilation (NIPPV) in COVID-19 AHRF and identify individual factors associated with failure. MethodsWe performed a retrospective cohort study of hospitalized adults with COVID-19 treated with HFNC and/or NIPPV to describe rates of success (live discharge without endotracheal intubation (ETI)), and identify characteristics associated with failure (ETI and/or in-hospital mortality) using Fine-Gray sub-distribution hazard models. ResultsA total of 331 and 747 patients received HFNC and NIPPV as the highest level of non-invasive respiratory support, respectively; 154 (46.5%) in the HFNC cohort and 167 (22.4%) in the NIPPV cohort were successfully discharged without requiring ETI. In adjusted models, significantly increased risk of HFNC and NIPPV failure was seen among patients with cardiovascular disease (subdistribution hazard ratio (sHR) 1.82; 95% confidence interval (CI), 1.17-2.83 and sHR 1.40; 95% CI 1.06-1.84), respectively, and among those with lower oxygen saturation to fraction of inspired oxygen (SpO2/FiO2) ratio at HFNC and NIPPV initiation (sHR, 0.32; 95% CI 0.19-0.54, and sHR 0.34; 95% CI 0.21-0.55, respectively). ConclusionsA significant proportion of patients receiving non-invasive respiratory modalities for COVID-19 AHRF achieved successful discharge without requiring ETI, with lower success rates among those with cardiovascular disease or more severe hypoxemia. The role of non-invasive respiratory modalities in COVID-19 related AHRF requires further consideration.

Associations between state-level healthcare access and COVID-19 case trajectories in the United States

IntroductionWe conducted an ecological study to determine if state-level healthcare access is associated with trajectories of daily reported COVID-19 cases in the United States. Our focus is on trajectories of daily reported COVID-19 cases, rather than cumulative cases, as trajectories help us identify trends in how the pandemic naturally develops over time, and study the shapes of the curve in different states. MethodsWe analyzed data on daily reported confirmed and probable COVID-19 cases from January 21 to June 16, 2020 in 50 states, adjusted for the population size of each state. Cluster analysis for time-series data was used to split the states into clusters that have distinct trajectories of daily cases. Differences in socio-demographic characteristics and healthcare access between clusters were tested. Adjusted models were used to determine if healthcare access is associated with reporting a high trajectory of COVID-19 cases. ResultsTwo clusters of states were identified. One cluster had a high trajectory of population- adjusted COVID-19 cases, and comprised of 19 states, including New York and New Jersey. The other cluster of states (n=31) had a low trajectory of population-adjusted COVID-19 cases. There were significantly more Black residents (p=0.027) and more nursing facility residents (p=0.001) in states reporting high trajectory of COVID-19 cases. States reporting a high trajectory of COVID-19 cases also had fewer uninsured persons (p=0.005), fewer persons who reported having to forgo medical care due to cost (p=0.016), more registered physicians (p=0.002) and more nurses (p=0.03), higher health spending per capita (p=0.01), fewer residents in Health Professional Shortage Areas per 100,000 population (p=0.027), and higher adoption of Medicaid Expansion (p=0.05). In adjusted models, a higher proportion of uninsured persons (OR: 0.51 [0.25-0.85]; p=0.032), higher proportion of patients who had to forgo medical care due to cost (OR: 0.55 [0.28-0.95]; p=0.048), and no adoption of Medicaid expansion (OR: 0.05 [0 - 0.59]; p=0.04), were associated with reporting a low trajectory of COVID-19 cases. ConclusionOur findings from adjusted models suggest that healthcare access can partially explain variations in COVID-19 case trajectories by state.

Time courses of COVID-19 infection and local variation in socioeconomic and health disparities in England

ObjectiveTo identify factors associated with local variation in the time course of COVID-19 case burden in England. MethodsWe analyzed laboratory-confirmed COVID-19 case data for 150 upper tier local authorities, from the period from January 30 to May 6, 2020, as reported by Public Health England. Using methods suitable for time-series data, we identified clusters of local authorities with distinct trajectories of daily cases, after adjusting for population size. We then tested for differences in sociodemographic, economic, and health disparity factors between these clusters. ResultsTwo clusters of local authorities were identified: a higher case trajectory that rose faster over time to reach higher peak infection levels, and a lower case trajectory cluster that emerged more slowly, and had a lower peak. The higher case trajectory cluster (79 local authorities) had higher population density (p<0.001), higher proportion of Black and Asian residents (p=0.03; p=0.02), higher multiple deprivation scores (p<0.001), a lower proportions of older adults (p=0.005), and higher preventable mortality rates (p=0.03). Local authorities with higher proportions of Black residents were more likely to belong to the high case trajectory cluster, even after adjusting for population density, deprivation, proportion of older adults and preventable mortality (p=0.04). ConclusionAreas belonging to the trajectory with significantly higher COVID-19 case burden were more deprived, and had higher proportions of ethnic minority residents. A higher proportion of Black residents in regions belonging to the high trajectory cluster was not fully explained by differences in population density, deprivation, and other overall health disparities between the clusters. What is already known on this subject?Emerging evidence suggests that the burden of COVID-19 infection is falling unequally across England, with provisional data suggesting higher overall infection and mortality rates for Black, Asian, and mixed race/ethnicity individuals. What does this study add?We found that regions with greater socioeconomic deprivation and poorer population health measures showed a faster rise in COVID-19 cases, and reached higher peak case levels. Areas with a higher proportion of Black residents were more likely to show this kind of time course, even after adjusting for multiple co-occurring factors, including population density. This finding merits further investigation in terms of the intersecting vulnerability factors Black and other minority ethnic individuals face in England (e.g. proportion of people working in service and caring roles, and the role of structural discrimination), and has implications for the ongoing allocation of public health resources, in order to better mitigate such inequalities.

Impaired brain network architecture in Cushing's disease based on graph theoretical analysis.

To investigate the whole functional brain networks of active Cushing disease (CD) patients about topological parameters (small world and rich club et al.) and compared with healthy control (NC). Nineteen active CD patients and twenty-two healthy control subjects, matched in age, gender, and education, underwent resting-state fMRI. Graph theoretical analysis was used to calculate the functional brain network organizations for all participants, and those for active CD patients were compared for and NCs. Active CD patients revealed higher global efficiency, shortest path length and reduced cluster efficiency compared with healthy control. Additionally, small world organization was present in active CD patients but higher than healthy control. Moreover, rich club connections, feeder connections and local connections were significantly decreased in active CD patients. Functional network properties appeared to be disrupted in active CD patients compared with healthy control. Analyzing the changes that lead to abnormal network metrics will improve our understanding of the pathophysiological mechanisms underlying CD.

The aging-liked alterations in Cushing's disease: A neurite orientation dispersion and density imaging (NODDI) study.

PURPOSE: Glucocorticoid (GC) is probably related to biological aging, but the exact mechanism remains unknown. Cushing's disease (CD) could represent a unique human model for examining the effects of prolonged exposure to hypercortisolism and its relationship with aging. Thus, we studied the alterations of neurites in CD patients with Neurite orientation dispersion and density imaging (NODDI). METHODS: CD patients (n = 15) and healthy control subjects (n = 15) were included in this study. Orientation dispersion index (Odi), neurite density index (Ndi), partial fraction of free water (fiso), partial fraction of extracellular water (fec) were examined in a cross-sectional analysis. RESULTS: Significant altered NODDI parameters were found in CD patients. Some of these alterations were correlated with current age. Additionally, increased dendritic density was found in cerebellar of CD patients. CONCLUSION: Hypercortisolism relative reductions of the dendritic density were correlated with current age in several regions of CD patients. Our study enhances the understanding of the link between the aging and GC.

Reversible and the irreversible structural alterations on brain after resolution of hypercortisolism in Cushing's disease.

The adverse effects of hypercortisolism on the human brain have been highlighted in previous studies of Cushing's disease (CD). However, the reversibility of brain damage after the resolution of hypercortisolism remains unclear. Thus, we studied the potential volumetric reversibility in biochemically remitted CD patients. Cross-sectional analysis demonstrated the active CD patients (n = 61) had the smallest gray matter (GM) volumes (553.33 ±â€¯45.90 CM3) among four groups. While the GM volumes of short-term remitted CD patients (586.62 ±â€¯46.89 CM3, n = 28) and long-term remitted CD patients (596.58 ±â€¯45.95 CM3, n = 35) were between those of the active CD patients and healthy control subjects (628.14 ±â€¯46.88 CM3, n = 74). Moreover, significant positive correlations between remitted time and GM volumes were only found in short-term remitted CD patients. On the contrary, the alterations of white matter (WM) in CD patients seem to be independent of concomitant hypercortisolism, persisting after remission. A preliminary longitude analysis also demonstrated similar results. Volumetric reversibility of GM, but not WM is highly prevalent in short-term after resolution of hypercortisolism in Cushing disease. Our study enhances our understanding of the reversible and the irreversible structural alterations in the human brain due to hypercortisolism.

PITUITARY STALK THICKENING IN A LARGE COHORT: TOWARD MORE ACCURATE PREDICTORS OF PITUITARY DYSFUNCTION AND ETIOLOGY.

Objective: To summarize the characteristics of patients with pituitary stalk thickening, analyze the association between pituitary stalk width and hypopituitarism, and develop a diagnostic model to differentiate neoplastic and inflammatory origins. Methods: A total of 325 patients with pituitary stalk thickening in a tertiary teaching hospital between January 2012 and February 2018 were enrolled. Basic characteristics and hormonal status were evaluated. Indicators to predict etiology in patients with histologic diagnoses were analyzed. Results: Of the 325 patients, 62.5% were female. Deficiency in gonadotropin was most common, followed by corticotropin, growth hormone, and thyrotropin. The increase in pituitary stalk width was associated with a risk of central diabetes insipidus (odds ratio [OR], 3.57; P<.001) and with a combination of central diabetes insipidus and anterior pituitary deficiency (OR, 2.28; P = .029). The cut-off pituitary stalk width of 4.75 mm had a sensitivity of 69.2% and a specificity of 71.4% for the presence of central diabetes insipidus together with anterior pituitary deficiency. Six indicators (central diabetes insipidus, pattern of pituitary stalk thickening, pituitary stalk width, neutrophilic granulocyte percentage, serum sodium level, and gender) were used to develop a model having an accuracy of 95.7% to differentiate neoplastic from inflammatory causes. Conclusion: Pituitary stalk width could indicate the presence of anterior pituitary dysfunction, especially in central diabetes insipidus patients. With the use of a diagnostic model, the neoplastic and inflammatory causes of pituitary stalk thickening could be preliminarily differentiated. Abbreviations: APD = anterior pituitary dysfunction; AUC = area under the curve; CDI = central diabetes insipidus; GH = growth hormone; MRI = magnetic resonance imaging; OR = odd ratio; PHBS = posterior hypophyseal bright spots; PST = pituitary stalk thickening; PSW = pituitary stalk width.

Directional multistage intraoperative microvascular Doppler in the hemilaminectomy surgical obliteration of spinal dural arteriovenous fistular.

OBJECTIVES: To present our experience with the use of microvascular Doppler measurement procedure in spinal dural arteriovenous fistula (sDAVF) surgery. PATIENTS AND METHODS: All patients with sDAVF from March 2008 to March 2017 who consecutively underwent hemilaminectomy surgical obliteration with the assistance of microvascular Doppler were included. We reviewed patient records, radiological images, operative notes, microvascular Doppler files, as well as intraoperative videos RESULTS: During the study period, 7 patients with sDAVF underwent surgical treatment facilitated by microvascular Doppler. Microvascular Doppler measurement was performed in all enrolled patients. Doppler measurement was reliable to define direction and the value of the flow of sDAVF vessels in all cases, thereby determining the location of fistula and confirming its obliteration. During temporary clip occlusion, Doppler identified successful disconnection in all cases by detecting a disappearance of arterial spectrum flow as well as a significant flow drop in venous drainages between before and after clip. At the final stage of obliteration, disappearance of the arterial spectrum and a significant flow drop in venous drainages was detected in all cases. No microflow probe-induced sDAVF vessel injury was detected. Complete obliteration of sDAVF was achieved in all cases. No recurrence was recorded during follow-up. CONCLUSION: Multistage intraoperative microvascular Doppler measurement proved to be a feasible, safe, repeatable, and reliable methodology to assist surgery in different phases of sDAVF obliteration. Further studies are needed to assess the impact of this approach on sDAVF patient outcomes.

MAGEA6 promotes human glioma cell survival via targeting AMPKα1.

Melanoma antigen A6 (MAGEA6)/TRIM28 complex is a cancer-specific ubiquitin ligase, which degradates tumor suppressor protein AMP-activated protein kinase (AMPK). We show that MAGEA6 is uniquely expressed in human glioma tissues and cells, which is correlated with AMPKα1 downregulation. It is yet absent in normal brain tissues and human astrocytes/neuronal cells. MAGEA6 knockdown by targeted-shRNA in glioma cells restored AMPKα1 expression, causing mTORC1 in-activation and cell death/apoptosis. Reversely, AMPKα1 knockdown or mutation ameliorated glioma cell death by MAGEA6 shRNA. In vivo, Glioma xenograft tumor growth in mice was largely inhibited following expressing MAGEA6 shRNA. AMPKα1 upregulation and mTORC1 inhibition were observed in MAGEA6 shRNA-bearing xenograft tissues. Collectively, MAGEA6 promotes glioma cell survival possibly via targeting AMPKα1.

Volumetric magnetic resonance imaging analysis in patients with short-term remission of Cushing's disease.

OBJECTIVE: The data on patients with short-term remission of Cushing's disease (CD) might provide information that is not available from previous long-term remission studies. We aimed to investigate structural changes in the brain in these patients and to examine whether these changes were associated with clinical characteristics. DESIGN: A cross-sectional study was performed. METHODS: Thirty-four patients with CD (14 with CD in short-term remission and 20 with active CD) and 34 controls matched for age, sex and education underwent clinical evaluation and magnetic resonance imaging brain scans. Biometric measurements, disease duration and remission duration data were collected. Grey matter volumes in the whole brain were examined using voxel-based morphometry (VBM). RESULTS: No differences were observed in the grey matter volumes of the medial frontal gyrus (MFG) and cerebellum between the patients with remitted CD and healthy controls, whereas patients with active CD had smaller grey matter volumes in these two regions compared with controls and patients with remitted CD. Furthermore, significant correlations were found between remission time and grey matter values in these regions in short-term remission patients with CD. Additionally, greater grey matter volumes in the bilateral caudate of short-term remission patients with CD were observed. CONCLUSIONS: Trends for structural restoration were found in CD patients with short-term remission. This finding was associated with the number of days elapsed since curative surgery and the current age of the patients. This study enhances our understanding of potential reversibility after the resolution of hypercortisolism in CD patients.

Altered gray and white matter microstructure in Cushing's disease: A diffusional kurtosis imaging study.

Exposure to chronic hypercortisolism has multiple adverse effects on brain biology in humans. Cushing's disease (CD) represents a unique and natural human model for examining the effects of hypercortisolism on the brain. This cross-sectional study used Diffusional Kurtosis Imaging (DKI) to investigate the microstructure alterations in both white matter (WM) and gray matter (GM) of CD patients and to determine the relationship of these changes with clinical characteristics. DKI images were obtained from 15 active CD patients. DKI parametric maps were estimated through voxel-based analyses (VBA) and compared with 15 healthy controls matched for age, sex and education. In addition, correlations were analyzed between the altered DKI parameters and clinical characteristics. Compared with healthy controls, CD patients mainly exhibited significantly altered diffuse parameters in the GM and WM of the left medial temporal lobe (MTL). The mean values of increased radial diffusivity (RD) of CD patients in GM of the left hippocampus/parahippocampal gyrus correlated positively with the clinical severity of CD. Additionally, we also found altered kurtosis parameters in the cerebellum and frontal lobe. DKI imaging of CD patients could represent complementary information in both white matter and gray matter. The impairment of the left MTL might explain some part of the memory and cognition impairments in CD patients.

Altered spontaneous brain activity in Cushing's disease: a resting-state functional MRI study.

CONTEXT AND OBJECTIVE: Cushing's disease (CD) provides a unique and naturalist model for studying the influence of hypercortisolism on the human brain and the reversibility of these effects after resolution of the condition. This cross-sectional study used resting-state fMRI (rs-fMRI) to investigate the altered spontaneous brain activity in CD patients and the trends for potential reversibility after the resolution of the hypercortisolism. We also aim to determine the relationship of these changes with clinical characteristics and cortisol levels. SUBJECTS AND METHODS: Active CD patients (n = 18), remitted CD patients (n = 14) and healthy control subjects (n = 22) were included in this study. Amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values were calculated to represent spontaneous brain activity. RESULTS: Our study resulted in three major findings: (i) active CD patients showed significantly altered spontaneous brain activity in the posterior cingulate cortex (PCC)/precuneus (PCu), occipital lobe (OC)/cerebellum, thalamus, right postcentral gyrus (PoCG) and left prefrontal cortex (PFC); (ii) trends for partial restoration of altered spontaneous brain activity after the resolution hypercortisolism were found in several brain regions; and (iii) active CD patients showed a significant correlation between cortisol levels and ALFF/ReHo values in the PCC/PCu, a small cluster in the OC and the right IPL. CONCLUSIONS: This study provides a new approach to investigating brain function abnormalities in patients with CD and enhances our understanding of the effect of hypercortisolism on the human brain. Furthermore, our explorative potential reversibility study of patients with CD may facilitate the development of future longitudinal studies.

Voltage-Dependent Anion Channel-1, a Possible Ligand of Plasminogen Kringle 5.

Kringle 5, the fifth fragment of plasminogen, is known to be important for inhibiting the proliferation and migration of vascular endothelial cell (VEC), while not having any effects on normal endothelial cells. Therefore, it may be a potential tumor therapy candidate. However, the ligand of the Kringle 5 in VEC has not yet been identified. In this study, the possible ligand of Kringle 5 in vitro was screened and validated using Ph.D.-7 phage display peptide library with molecular docking, along with surface plasma resonance (SPR). After four rounds of panning, the specific clones of Kringle 5 were confirmed using enzyme-linked immunosorbent assay (ELISA). The gene sequence analysis showed that they expressed the common amino sequence IGNSNTL. Then, using a NCBI BLAST, 103 matching sequences were found. Following the molecular docking evaluation and considering the acting function and pathway of the plasminogen Kringle 5 in the human body, the most promising candidate was determined to be voltage-dependent anion channel-1 (VDAC-1), which was able to bind to Kringle 5 at -822.65 J·mol-1 of the binding energy at the residues of Lys12, Thr19, Ser57, Thr188, Arg139, Asn214, Ser240 and Lys274. A strong dose-dependent interaction occurred between the VDAC-1 and Kringle 5 (binding constant 2.43 × 103 L·mol-1) in SPR observation. Therefore, this study proposed that VDAC-1 was a potential ligand of plasminogen Kringle 5, and also demonstrated that the screening and validation of protein ligand using phage display peptide library with the molecular docking, along with SPR, was a practicable application.

GSK621 Targets Glioma Cells via Activating AMP-Activated Protein Kinase Signalings.

Here, we studied the anti-glioma cell activity by a novel AMP-activated protein kinase (AMPK) activator GSK621. We showed that GSK621 was cytotoxic to human glioma cells (U87MG and U251MG lines), possibly via provoking caspase-dependent apoptotic cell death. Its cytotoxicity was alleviated by caspase inhibitors. GSK621 activated AMPK to inhibit mammalian target of rapamycin (mTOR) and downregulate Tetraspanin 8 (Tspan8) in glioma cells. AMPK inhibition, through shRNA knockdown of AMPKα or introduction of a dominant negative (T172A) AMPKα, almost reversed GSK621-induced AMPK activation, mTOR inhibition and Tspan8 degradation. Consequently, GSK621's cytotoxicity in glioma cells was also significantly attenuated by AMPKα knockdown or mutation. Further studies showed that GSK621, at a relatively low concentration, significantly potentiated temozolomide (TMZ)'s sensitivity and lethality against glioma cells. We summarized that GSK621 inhibits human glioma cells possibly via activating AMPK signaling. This novel AMPK activator could be a novel and promising anti-glioma cell agent.

Inhibition of Ubiquitin-specific Peptidase 8 Suppresses Adrenocorticotropic Hormone Production and Tumorous Corticotroph Cell Growth in AtT20 Cells.

BACKGROUND: Two recent whole-exome sequencing researches identifying somatic mutations in the ubiquitin-specific protease 8 (USP8) gene in pituitary corticotroph adenomas provide exciting advances in this field. These mutations drive increased epidermal growth factor receptor (EGFR) signaling and promote adrenocorticotropic hormone (ACTH) production. This study was to investigate whether the inhibition of USP8 activity could be a strategy for the treatment of Cushing's disease (CD). METHODS: The anticancer effect of USP8 inhibitor was determined by testing cell viability, colony formation, apoptosis, and ACTH secretion. The immunoblotting and quantitative reverse transcription polymerase chain reaction were conducted to explore the signaling pathway by USP8 inhibition. RESULTS: Inhibition of USP8-induced degradation of receptor tyrosine kinases including EGFR, EGFR-2 (ERBB2), and Met leading to a suppression of AtT20 cell growth and ACTH secretion. Moreover, treatment with USP8 inhibitor markedly induced AtT20 cells apoptosis. CONCLUSIONS: Inhibition of USP8 activity could be an effective strategy for CD. It might provide a novel pharmacological approach for the treatment of CD.