Negative Impact of COVID-19 Upon Primary Brain Tumor Care.

Meningiomas are the most common primary central nervous system tumors, as they can account for up to one-third of all primary brain tumors. Most meningiomas are benign, although up to one-fourth of such tumors are classified as atypical or malignant. Atypical and malignant meningiomas are associated with an increased risk of local recurrence and decreased overall survival. Our patient is a 57-year-old male with a history of recurrent malignant meningioma, with metastasis to the liver. He underwent multiple surgical interventions, radiation treatments, and systemic therapies for a malignant meningioma, ultimately requiring transfer to hospice care. Not only did a positive novel coronavirus (COVID-19) infection delay his ability to receive radiation therapy, the infection in itself may have had an impact on the course of care for this patient. Treatment targeting the patient's COVID-19 infection may have suppressed the immune system, and as a result, caused the progression of metastatic disease. Palliative care was needed in the setting of losing all functional goals for quality of life due to malignant neoplasm.

Upregulation of MicroRNA miR-9 Is Associated with Microcephaly and Zika Virus Infection in Mice.

Proper growth of the mammalian cerebral cortex, which is determined by expansion and survival of neural progenitors and mature neurons, is crucial for cognitive functions. Here, we show a role of the dosage of microRNA miR-9 in controlling brain size. Cortical-specific upregulation of miR-9 causes microcephalic defects in mice, due to apoptosis, reduced neural progenitor pool, and decreased neurogenesis. Glial cell-derived neurotrophic factor (GDNF) is a target of miR-9, and protects neural progenitors from miR-9-induced apoptosis. Furthermore, Zika virus (ZIKV) infection in embryonic mouse cortex causes reduced numbers in neural progenitors and newborn neurons, and results in upregulation of miR-9, downregulation of its target GDNF. Our studies indicate an association of altered levels of miR-9 and its target GDNF with microcephaly and ZIKV infection in mice.

Counter-Balance Between Gli3 and miR-7 Is Required for Proper Morphogenesis and Size Control of the Mouse Brain.

Brain morphogenesis requires precise regulation of multiple genes to control specification of distinct neural progenitors (NPs) and neuronal production. Dysregulation of these genes results in severe brain malformation such as macrocephaly and microcephaly. Despite studies of the effect of individual pathogenic genes, the counter-balance between multiple factors in controlling brain size remains unclear. Here we show that cortical deletion of Gli3 results in enlarged brain and folding structures in the cortical midline at the postnatal stage, which is mainly caused by the increased percentage of intermediate progenitors (IPs) and newborn neurons. In addition, dysregulation of neuronal migration also contributes to the folding defects in the cortical midline region. Knockdown of microRNA (miRNA) miR-7 can rescue abnormal brain morphology in Gli3 knockout mice by recovering progenitor specification, neuronal production and migration through a counter-balance of the Gli3 activity. Moreover, miR-7 likely exerts its function through silencing target gene Pax6. Our results indicate that proper brain morphogenesis is an outcome of interactive regulations of multiple molecules such as Gli3 and miR-7. Because miRNAs are easy to synthesize and deliver, miR-7 could be a potential therapeutic means to macrocephaly caused by Gli3-deficiency.

Opposite Roles of Wnt7a and Sfrp1 in Modulating Proper Development of Neural Progenitors in the Mouse Cerebral Cortex.

The Wingless (Wnt)-mediated signals are involved in many important aspects of development of the mammalian cerebral cortex. How Wnts interact with their modulators in cortical development is still unclear. Here, we show that Wnt7a and secreted frizzled-related protein 1 (Sfrp1), a soluble modulator of Wnts, are co-expressed in mouse embryonic cortical neural progenitors (NPs). Knockout of Wnt7a in mice causes microcephaly due to reduced NP population and neurogenesis, and Sfrp1 has an opposing effect compared to Wnt7a. Similar to Dkk1, Sfrp1 decreases the Wnt1 and Wnt7a activity in vitro. Our results suggest that Wnt7a and Sfrp1 play opposite roles to ensure proper NP progeny in the developing cortex.