Neuroglia, Volume 4, Issue 1 (March 2023) – 6 articles

We previously reported on the experimental validation of several in silico-predicted glioma biomarkers (e.g., Plexin-B2 (PLXNB2), SLIT3, and Spondin-1 (SPON1)) that were found to be higher in human high-grade gliomas (HGGs). In this study, we validated their therapeutic potential by investigating antibody therapies against these three biomarkers in a preclinical mouse GL261 high-grade glioma model. Efficacies for antibody therapies against these biomarkers were assessed by survival and tumor volumes, biomarker expressions, cell invasion and proliferation, and bioinformatics gene/protein associations. Antibodies against PLXNB2, SLIT3, or SPON1 were effective in significantly reducing tumor volumes and increasing animal survival. With immunohistochemistry (IHC), these biomarkers were highly expressed in human HGGs, as well as in mice tumors. From IHC, CD44v6 was significantly decreased for all three antibody treatments, compared to UT GL261 tumors. Bioinformatics suggested that targeting either PLXNB2 or SPON1 may have a major effect on HGG cell migration and invasion (validated with CD44v6 IHC), whereas targeting SLIT3, in addition to affecting cell invasion, may also affect cell proliferation (not validated with Ki67 IHC). These results indicate that targeting these three biomarkers could add to the therapeutic arsenal against high-grade gliomas and that antibodies against them could be considered for clinical translation. Full article

Spinocerebellar ataxia type 1 (SCA1) is a fatal, dominantly inherited neurodegenerative disease caused by the expansion of CAG repeats in the Ataxin-1 (ATXN1) gene. SCA1 is characterized by the early and prominent pathology of the cerebellar Purkinje cells that results in balance and coordination deficits. We previously demonstrated that cerebellar astrocytes contribute to SCA1 pathogenesis in a biphasic, stage of disease-dependent manner. We found that pro-inflammatory transcriptional regulator nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling in astrocytes has a neuroprotective role during early-stage SCA1. Here, we sought to examine whether further inducing NF-κB activation in astrocytes of SCA1 model mice at an early stage of the disease has therapeutic benefits. To perform this task, we created a novel Slc1a3-CreER^T/IKKβ_CA/ATXN1[82Q] triple transgenic mouse model in which TMX injection at 4 weeks of age results in the expression of constitutively active inhibitor of kB kinase beta (IKKβ_CA), the main activator of NF-κB signaling. As we evaluated SCA1-like phenotypes, we noticed that ATXN1[82Q] mice did not exhibit motor deficits anymore, even at very late stages of the disease. We sequenced the mutant ATXN1 gene and discovered that the CAG repeat number had decreased from 82 to 71. However, despite the loss of motor phenotype, other well-characterized SCA1-changes, including atrophy of Purkinje cell dendrites, hallmarks of cerebellar astrogliosis and microgliosis, and Purkinje cell disease-associated gene expression changes, were still detectable in ATXN1[71Q] mice. We found delayed PC atrophy and calbindin reduction in SCA1 mice expressing IKKβ_CA in astrocytes implicating beneficial effects of increased NF-κB signaling on Purkinje cell pathology. The change in the motor phenotype of SCA1 mice with CAG reduction prevented us from evaluating the neuroprotective potential of IKKβ_CA on motor deficits in these mice. Full article

Astrocytes and microglia play important roles in organizing the structure and function of neuronal networks in the central nervous system (CNS). The dorsal diencephalic connection system (DDCS) is a phylogenetically ancient regulatory system by which the forebrain influences the activity of cholinergic and ascending monoaminergic pathways in the midbrain. The DDCS is probably important in inducing aspects of mental disorders, such as depression and addiction. The habenula is the small but highly complex connecting center of the DDCS in the epithalamus that consists of a medial (MHb) and lateral (LHb) division. MHb and LHb are built differently and connect different brain structures. Studies in animal models and human biomarker research provide good evidence that astroglia and microglia also affect the symptoms of mental disorders (such as depression). The significance of these neuroglia in habenular neurotransmission has not been extensively studied. This review article provides arguments for doing so more thoroughly. Full article

Glioma, specifically gliobastoma, represents the commonest central nervous system malignancy and is notoriously challenging to treat, with only a minimal number of patients surviving beyond a year after diagnosis. The available treatment options include surgical resection, radiotherapy, and chemotherapy, mainly with temozolomide. However, gliomas can be particularly treatment resistant and novel options are currently being researched. One such agent is ONC201, the first member of the imipridone class and a TNF-related apoptosis inducing ligand (TRAIL)-inducing compound, which has shown positive results in the first preliminary clinical reports about its application in glioma patients, while also being safe and well-tolerated. Particular promise has been shown for the H3K27M mutated glioblastomas, with more trials focusing on this patient subset. It is likely that this compound will be added in the treatment algorithms of glioma in the future, although more research is still needed. Full article

Chronic itch (CI) is an unpleasant skin sensation accompanied by an intense scratching desire that lasts 6 weeks or longer. Despite the high prevalence and negative impact on affected individuals and a huge healthcare burden, CI mechanisms are only partially understood, and consequently, treatment of CI remains sub-optimal. The complexity of CI treatment also stems from the comorbid existence of persistent itch with other somatic and psychological disorders. Etiologies of CI are multiple and diverse, although CI is often a result of dermatologically related conditions such as atopic dermatitis and psoriasis. Unfolding the pathophysiology of CI can provide possibilities for better therapy. Itch signaling is complex and neurons and non-neuronal cells play a role. This review focuses on recent findings on the role of glial cells in itch. Central glia (astrocytes and microglia) and peripheral glia (satellite glial cells and Schwann cells) are found to contribute to the development or persistence of itch. Hence, glial modulation has been proposed as a potential option in CI treatment. In experimental models of itch, the blockade of signal transducer and the activator of transcription (STAT) 3-mediated reactive astrogliosis have been shown to suppress chronic itch. Administration of a microglial inhibitor, minocycline, has also been demonstrated to suppress itch-related microglial activation and itch. In sensory ganglia, gap-junction blockers have successfully blocked itch, and hence, gap-junction-mediated coupling, with a potential role of satellite glial cells have been proposed. This review presents examples of glial involvement in itch and opportunities and challenges of glial modulation for targeting itch. Full article

Contemporary research has found that people with autism spectrum disorder (ASD) exhibit aberrant immunological function, with a shift toward increased cytokine production and unusual cell function. Microglia and astroglia were found to be significantly activated in immuno-cytochemical studies, and cytokine analysis revealed that the macrophage chemoattractant protein-1 (MCP-1), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and transforming growth factor β-1 (TGFB-1), all generated in the neuroglia, constituted the most predominant cytokines in the brain. Taurine (2-aminoethanesulfonic acid) is a promising therapeutic molecule able to increase the activity of antioxidant enzymes and ATPase, which may be protective against aluminum-induced neurotoxicity. It can also stimulate neurogenesis, synaptogenesis, and reprogramming of proinflammatory M1 macrophage polarization by decreasing mitophagy (mitochondrial autophagy) and raising the expression of the markers of the anti-inflammatory and pro-healing M2 macrophages, such as macrophage mannose receptor (MMR, CD206) and interleukin 10 (IL-10), while lowering the expression of the M1 inflammatory factor genes. Taurine also induces autophagy, which is a mechanism that is impaired in microglia cells and is critically associated with the pathophysiology of ASD. We hypothesize here that taurine could reprogram the metabolism of M1 macrophages that are overstimulated in the nervous system of people suffering from ASD, thereby decreasing the neuroinflammatory process characterized by autophagy impairment (due to excessive microglia activation), neuronal death, and improving cognitive functions. Therefore, we suggest that taurine can serve as an important lead for the development of novel drugs for ASD treatment. Full article