The OTX2 Gene Induces Tumor Growth and Triggers Leptomeningeal Metastasis by Regulating the mTORC2 Signaling Pathway in Group 3 Medulloblastomas.

Medulloblastoma (MB) encompasses diverse subgroups, and leptomeningeal disease/metastasis (LMD) plays a substantial role in associated fatalities. Despite extensive exploration of canonical genes in MB, the molecular mechanisms underlying LMD and the involvement of the orthodenticle homeobox 2 (OTX2) gene, a key driver in aggressive MB Group 3, remain insufficiently understood. Recognizing OTX2's pivotal role, we investigated its potential as a catalyst for aggressive cellular behaviors, including migration, invasion, and metastasis. OTX2 overexpression heightened cell growth, motility, and polarization in Group 3 MB cells. Orthotopic implantation of OTX2-overexpressing cells in mice led to reduced median survival, accompanied by the development of spinal cord and brain metastases. Mechanistically, OTX2 acted as a transcriptional activator of the Mechanistic Target of Rapamycin (mTOR) gene's promoter and the mTORC2 signaling pathway, correlating with upregulated downstream genes that orchestrate cell motility and migration. Knockdown of mTOR mRNA mitigated OTX2-mediated enhancements in cell motility and polarization. Analysis of human MB tumor samples (N = 952) revealed a positive correlation between OTX2 and mTOR mRNA expression, emphasizing the clinical significance of OTX2's role in the mTORC2 pathway. Our results reveal that OTX2 governs the mTORC2 signaling pathway, instigating LMD in Group 3 MBs and offering insights into potential therapeutic avenues through mTORC2 inhibition.

Antibody Profiling and In Silico Functional Analysis of Differentially Reactive Antibody Signatures of Glioblastomas and Meningiomas.

Studies on tumor-associated antigens in brain tumors are sparse. There is scope for enhancing our understanding of molecular pathology, in order to improve on existing forms, and discover new forms, of treatment, which could be particularly relevant to immuno-oncological strategies. To elucidate immunological differences, and to provide another level of biological information, we performed antibody profiling, based on a high-density protein array (containing 8173 human transcripts), using IgG isolated from the sera of n = 12 preoperative and n = 16 postoperative glioblastomas, n = 26 preoperative and n = 29 postoperative meningiomas, and n = 27 healthy, cancer-free controls. Differentially reactive antigens were compared to gene expression data from an alternate public GBM data set from OncoDB, and were analyzed using the Reactome pathway browser. Protein array analysis identified approximately 350-800 differentially reactive antigens, and revealed different antigen profiles in the glioblastomas and meningiomas, with approximately 20-30%-similar and 10-15%-similar antigens in preoperative and postoperative sera, respectively. Seroreactivity did not correlate with OncoDB-derived gene expression. Antigens in the preoperative glioblastoma sera were enriched for signaling pathways, such as signaling by Rho-GTPases, COPI-mediated anterograde transport and vesicle-mediated transport, while the infectious disease, SRP-dependent membrane targeting cotranslational proteins were enriched in the meningiomas. The pre-vs. postoperative seroreactivity in the glioblastomas was enriched for antigens, e.g., platelet degranulation and metabolism of lipid pathways; in the meningiomas, the antigens were enriched in infectious diseases, metabolism of amino acids and derivatives, and cell cycle. Antibody profiling in both tumor entities elucidated several hundred antigens and characteristic signaling pathways that may provide new insights into molecular pathology and may be of interest for the development of new treatment strategies.

Extracellular-Vesicle-Based Cancer Panels Diagnose Glioblastomas with High Sensitivity and Specificity.

Glioblastoma is one of the most devastating neoplasms of the central nervous system. This study focused on the development of serum extracellular vesicle (EV)-based glioblastoma tumor marker panels that can be used in a clinic to diagnose glioblastomas and to monitor tumor burden, progression, and regression in response to treatment. RNA sequencing studies were performed using RNA isolated from serum EVs from both patients (n = 85) and control donors (n = 31). RNA sequencing results for preoperative glioblastoma EVs compared to control EVs revealed 569 differentially expressed genes (DEGs, 2XFC, FDR < 0.05). By using these DEGs, we developed serum-EV-based biomarker panels for the following glioblastomas: wild-type IDH1 (96% sensitivity/80% specificity), MGMT promoter methylation (91% sensitivity/73% specificity), p53 gene mutation (100% sensitivity/89% specificity), and TERT promoter mutation (89% sensitivity/100% specificity). This is the first study showing that serum-EV-based biomarker panels can be used to diagnose glioblastomas with a high sensitivity and specificity.

SRPX Emerges as a Potential Tumor Marker in the Extracellular Vesicles of Glioblastoma.

Extracellular vesicles (EVs) may be used as a non-invasive screening platform to discover markers associated with early diagnosis, prognosis, and treatment response. Such an approach is invaluable for diseases such as glioblastoma, for which only a few non-invasive diagnostic or prognostic markers are available. We used mass spectrometry to analyze proteomics profiles of EVs derived from four glioblastoma cell lines and human primary astrocytes (HPAs) and found that SRPX is the only protein enriched in the majority of glioblastoma EVs that was absent in the HPA-derived EVs. Then, we evaluated the relationship between SRPX protein expression and tumor grade using immunohistochemical staining (IHC) and performed colony formation and viability assays to analyze the possible function of SRPX in glioblastoma. SRPX mRNA and protein expression were associated with tumor grade. Moreover, temozolomide (TMZ)-resistant tumor tissues showed highly positive SRPX staining, compared to all other tumor grades. Additionally, glioblastoma cells displayed enhanced SRPX gene expression when exposed to TMZ. Knockdown of SRPX gene expression via siRNA inhibited cell viability. Taken together, the results of this study suggest that SRPX can be used as a novel tumor marker for diagnostic and prognostic purposes and can also be a therapeutic target for glioblastomas.

Cephalometric and Functional Mandibular Reconstructive Outcomes Using a Horizontal Scapular Tip Free Flap.

Scapula tip free flaps (STFFs) have become an increasingly popular option for head and neck reconstruction. The aim of this study is to demonstrate the feasibility of using the STFF in a horizontal orientation to take advantage of the anatomy of the scapular tip bone to re-create a mandibular symphysis. Eight patients underwent oromandibular reconstruction with a horizontally oriented STFF between October 2016 and June 2020. Virtual surgical planning was used to design the bony reconstruction in 6 cases. Primary outcomes, including flap survival, complications, and return to oral diet, were collected. Cephalometric measurements were obtained to compare preoperative and postoperative mandibular projection and width. All flaps survived without compromise, and no fistulas developed postoperatively. Seven patients returned to taking an oral diet. Cephalometric analysis revealed comparable measurements between preoperative and postoperative mandibles and reconstructed mandibles, respectively. STFFs may be oriented horizontally to reconstruct large anterior mandibular defects with satisfactory results.

An AMPK-dependent regulatory pathway in tau-mediated toxicity.

Neurodegenerative tauopathies are characterised by accumulation of hyperphosphorylated tau aggregates primarily degraded by autophagy. The 5'AMP-activated protein kinase (AMPK) is expressed in most cells, including neurons. Alongside its metabolic functions, it is also known to be activated in Alzheimer's brains, phosphorylate tau, and be a critical autophagy activator. Whether it plays a neurotoxic or neuroprotective role remains unclear. In tauopathies stress conditions can result in AMPK activation, enhancing tau-mediated toxicity. Paradoxically, in these cases AMPK activation does not always lead to protective autophagic responses. Using a Drosophila in vivo quantitative approach, we have analysed the impact of AMPK and autophagy on tau-mediated toxicity, recapitulating the AMPK-mediated tauopathy condition: increased tau phosphorylation, without corresponding autophagy activation. We have demonstrated that AMPK binding to and phosphorylating tau at Ser-262, a site reported to facilitate soluble tau accumulation, affects its degradation. This phosphorylation results in exacerbation of tau toxicity and is ameliorated via rapamycin-induced autophagy stimulation. Our findings support the development of combinatorial therapies effective at reducing tau toxicity targeting tau phosphorylation and AMPK-independent autophagic induction. The proposed in vivo tool represents an ideal readout to perform preliminary screening for drugs promoting this process.

Retinal haemorrhage in infants with pertussis.

AIMS: It has been hypothesised that paroxysmal coughing in infantile pertussis (whooping cough) could produce retinal haemorrhages identical to those seen in abusive head trauma. We aimed to test this hypothesis. METHODS: This is a prospective study of infants hospitalised with pertussis in Auckland, New Zealand, from 2009 to 2014. The clinical severity of pertussis was categorised. All infants recruited had retinal examination through dilated pupils by the paediatric ophthalmology service using an indirect ophthalmoscope. RESULTS: Forty-eight infants with pertussis, aged 3 weeks to 7 months, were examined after a mean of 18 days of coughing. Thirty-nine had severe pertussis and nine had mild pertussis. All had paroxysmal cough, and all were still coughing at the time of examination. No retinal haemorrhages were seen. CONCLUSIONS: We found no evidence to support the hypothesis that pertussis may cause the pattern of retinal haemorrhages seen in abusive head trauma in infants.

Child morbidity as described by hospital admissions for primary school aged children in Tonga 2009-2013.

AIMS: To describe inpatient utilisation patterns for primary school aged children in Tonga. METHODS: We described admissions for children aged 5-11 years to the main hospital in Tonga from January 2009 to December 2013. Rates with 95% confidence intervals (CI) were compared using rate ratios (RR). RESULTS: There were 1,816 admissions. The average annual admission rate was 20.2/1,000 (95% CI 19.3-21.1). Hospital admission rates were higher in younger than older children (5-7 versus 8-11 years, RR=1.28, 95% CI 1.18-1.41) and in boys than girls (RR=1.52, 95% CI 1.38-1.68). Injury and poisoning (28%), non-respiratory infectious diseases (19%), respiratory conditions (16%), abdominal/surgical conditions (13%) and dental (9%) were the most frequent admission reasons. A larger proportion of younger versus older children were hospitalised for dental (16% vs 1%, P<0.001) or respiratory conditions (18% vs 14%, P=0.02). A larger proportion of older children were hospitalised for abdominal/surgical conditions (15% vs 11%, P=0.008), other infectious diseases (21% vs 17%, P=0.04), other conditions (10% vs 6%, P<0.001) and cardiac conditions (2% vs 1%, P<0.001). CONCLUSIONS: In children 5-11 years in Tonga, 85% of admissions were for five groups of conditions. These data inform priority areas for healthcare spending and enable comparisons over time and between different Pacific countries.

Vitamin D status of exclusively breastfed infants aged 2-3 months.

BACKGROUND: New Zealand in 2008 adopted WHO policy which recommends that all infants are exclusively breast fed until 6 months of age. The benefits of this policy for the infant are undisputed; however, this policy has the potential to adversely impact on infant vitamin D status. A number of countries now recommend that all breastfed infants receive daily vitamin D supplementation of 400 IU to prevent rickets. New Zealand has no policy on the vitamin D supplementation of 'low-risk' breastfed infants. There are no data on the vitamin D status of exclusively breastfed infants in the first few months of life in New Zealand. AIM: To describe serum 25-hydroxy-vitamin D (25(OH)D) concentrations in exclusively breastfed infants aged 2-3 months. DESIGN/METHODS: Healthy term exclusively breastfed infants who were receiving no vitamin D supplements were enrolled over a 15-month period. A capillary blood sample was obtained from each infant. Serum 25(OH)D was measured using isotope-dilution liquid chromatography-tandem mass spectrometry. RESULTS: 94 infants were enrolled (mean age 10 weeks). Median 25(OH)D concentration was 53 nmol/l (IQR 14-100 nmol/l). 23 (24%) infants had serum 25(OH)D concentration <27.5 nmol/l. Infants enrolled during winter had a median (IQR) 25(OH)D serum concentration of 21 nmol/l (14,31). Infants enrolled during summer had a median (IQR) 25(OH)D concentration of 75 nmol/l (55 100) (winter vs summer, p<0.0001). CONCLUSIONS: Vitamin D deficiency is prevalent in exclusively breastfed infants in New Zealand. Vitamin D supplementation should be considered as part of New Zealand's child health policy.

Return of bradykinesia after subthalamic stimulation ceases: relationship to electrode location.

In 20 subjects we quantified the rate at which subthalamic nucleus deep brain stimulation effects on Parkinson's bradykinesia "washed-out" after stimulation ceased. We found that wash-out was a two-step process, consisting of an initial fast decrease in stimulation's therapeutic effect, followed by a further, slow decline. Moreover, the relative contribution of the fast and slow components differed between patients. Finally, we found that lateral stimulation caused more of the fast-decaying component, while medial stimulation caused more of the slow-decaying component. This implies the existence of at least two separate mechanisms by which subthalamic nucleus deep brain stimulation improves bradykinesia, associated with activation of spatially separate zones in the vicinity of the subthalamic nucleus.