While comprehensive molecular profiling of histone H3.3 mutant pediatric high-grade glioma has revealed extensive dysregulation of the chromatin landscape, the exact mechanisms driving tumor formation remain poorly understood. Since H3.3 mutant gliomas also exhibit high levels of copy number alterations, we set out to address if the H3.3K27M oncohistone leads to destabilization of the genome. Hereto, we established a cell culture model allowing inducible H3.3K27M expression and observed an increase in mitotic abnormalities. We also found enhanced interaction of DNA replication factors with H3.3K27M during mitosis, indicating replication defects. Further functional analyses revealed increased genomic instability upon replication stress, as represented by mitotic bulky and ultrafine DNA bridges. This co-occurred with suboptimal 53BP1 nuclear body formation after mitosis in vitro, and in human glioma. Finally, we observed a decrease in ultrafine DNA bridges following deletion of the K27M mutant H3F3A allele in primary high-grade glioma cells. Together, our data uncover a role for H3.3 in DNA replication under stress conditions that is altered by the K27M mutation, promoting genomic instability and potentially glioma development.

Sonic hedgehog (SHH) medulloblastoma originates from the cerebellar granule neuron progenitor (CGNP) lineage, which depends on Hedgehog signaling for its perinatal expansion. Whereas SHH tumors exhibit overall deregulation of this pathway, they also show patient age-specific aberrations. To investigate whether the developmental stage of the CGNP can account for these age-specific lesions, we analyzed developing murine CGNP transcriptomes and observed highly dynamic gene expression as a function of age. Cross-species comparison with human SHH medulloblastoma showed partial maintenance of these expression patterns, and highlighted low primary cilium expression as hallmark of infant medulloblastoma and early embryonic CGNPs. This coincided with reduced responsiveness to upstream SHH pathway component Smoothened, whereas sensitivity to downstream components SUFU and GLI family proteins was retained. Together, these findings can explain the preference for SUFU mutations in infant medulloblastoma and suggest that drugs targeting the downstream SHH pathway will be most appropriate for infant patients.

Effects of Peel Extract from Citrus reticulata and Hesperidin, A Citrus Flavonoid, on Macrophage Cell Line

Medulloblastoma is a pediatric brain malignancy that consists of four transcriptional subgroups. Structural and numerical aneuploidy are common in all subgroups, although they are particularly profound in Group 3 and Group 4 medulloblastoma and in a subtype of SHH medulloblastoma termed SHHα. This suggests that chromosomal instability (CIN), the process leading to aneuploidy, is an important player in medulloblastoma pathophysiology. However, it is not known if there is ongoing CIN in medulloblastoma or if CIN affects the developing cerebellum and promotes tumor formation. To investigate this, we performed karyotyping of single medulloblastoma cells and demonstrated the presence of distinct tumor cell clones harboring unique copy number alterations, which is suggestive of ongoing CIN. We also found enrichment for processes related to DNA replication, repair, and mitosis in both SHH medulloblastoma and in the highly proliferative compartment of the presumed tumor cell lineage-of-origin, the latter also being sensitive to genotoxic stress. However, when challenging these tumor cells-of-origin with genetic lesions inducing CIN using transgenic mouse modeling, we found no evidence for large chromosomal aberrations in the cerebellum or for medulloblastoma formation. We therefore conclude that without a background of specific genetic mutations, CIN is not tolerated in the developing cerebellum in vivo and, thus, by itself is not sufficient to initiate medulloblastoma.

The number of neurons in the sensory ganglion decreases after a peripheral nerve injury (PNI) caused by oral trauma or maxillofacial surgery, resulting in an incomplete nerve regeneration process. Thus, there is an urgent need to reduce the risk for potential complications after PNI, including neuropathic/ectopic pain and allodynia. Citicoline administration reportedly can improve motor function and prevent neuropathic pain in a rat model of PNI. Therefore, the present study aimed to assess the effect of citicoline administration on Brain-derived neurotrophic factor (Bdnf) expression, which is an early indicator of an ongoing nerve regeneration process, and the number of trigeminal neurons at the chronic phase after a PNI in a rat model. The PNI model was established by clamping the mental nerve of Wistar rats with a non-serrated clamp for 30 s. The animals were divided into the following three groups: sham-operated; clamp-injured rats receiving saline as the controls; and clamp-injured rats receiving a daily dose citicoline 50 mg/100g body weight intraperitoneally immediately after surgery for 7 days. They were sacrificed on days 1,3, and 7 for the acute phase analysis to examine the changes in Bdnf expression using quantitative reverse transcriptio polymerase chain reaction. Subsequently, the chronic phase analysis was done by counting the neuron number in the trigeminal ganglion on day 28 post-injury using the stereological method. In the acute phase, citicoline administration increased the Bdnf expression by 2.19 times only on the third-day post-injury, indicating the start of an early regenerative process. However, in the chronic phase, the total number of neurons in the trigeminal ganglion remained similar in all groups, suggesting the possibility of inadequate injury level. In conclusion, although there was no neuronal loss after a mental nerve injury, citicoline administration increased the Bdnf expression at the trigeminal ganglion immediately after the nerve injury, and this may accelerate nerve regeneration.

Controlling the vector by eradicating mosquito larvae is frequently done by spreading Abate powder containing 1% Temephos as a larvicide agent. However, the use of Abate powder will possibly increase pesticide residue contamination in the water. This study aimed to explore the potential use of ethanolic extract from red dragon fruit skin to kill mosquito larvae. An experimental laboratory study was performed to examine the larvicidal activity of ethanolic extract from red dragon fruit skin. Maceration method was used to extract active compounds from the fruit skin. Subsequently, the viscous extract was formulated using the wet granulation method to obtain powder form. The larvicide test was done by comparing the lethal concentration (LC50) of mosquito larvae after treatment using the extract and the reference larvicide agent, 1% Temephos Abate. The treatment groups consisted of four different extract concentrations of 1%, 2%, 3%, and 4%. The LC50 of each treatment groups was then calculated against the negative control group. Phytochemical screening showed that the ethanol extract of red dragon fruit skin contains alkaloids, flavonoids, saponins, triterpenoids, and tannins. The larvicide test on Aedes aegypti mosquito larvae showed that the extract treatment hardly killed the Aedes aegypti mosquito larvae. However, on Culex mosquito larvae, the ethanolic extract of red dragon fruit skin was able to kill mosquito larvae, with LC50 value of of 19.06%. The ethanolic extract of red dragon fruit skin was effective on killing the Culex mosquito larvae but not the Aedes aegypti mosquito larvae.