Enhanced Microglia Activation and Glioma Tumor Progression by Inflammagen Priming in Mice with Tumor Necrosis Factor Receptor Type 2 Deficiency

Receptors on Microglia

Microglial cells are the most receptive cells in the central nervous system (CNS), expressing several classes of receptors reflecting their immune heritage and newly acquired neural specialisation. Microglia possess, depending on the particular context, receptors to neurotransmitters and neuromodulators as well as immunocompetent receptors. This rich complement allows microglial cells to monitor the functional status of the nervous system, contribute actively to the regulation of neural activity and plasticity and homeostasis, and guard against pathogens as well as other challenges to the CNS's integrity and function.

The Influence of Severity and Disease Duration on TNF Receptors' Redistribution in Asthma and Rheumatoid Arthritis

One of the mechanisms of cellular dysfunction during the chronization of immune-system-mediated inflammatory diseases is a change in the profile of expression and co-expression of receptors on cells. The aim of this study was to compare patterns of redistribution of TNF receptors (TNFRs) among patients with different durations of rheumatoid arthritis (RA) or asthma. Subgroup analysis was performed on RA (n = 41) and asthma (n = 22) patients with disease duration<10 years and >10 years and on 30 comparable healthy individuals. The co-expression profile of TNFR1 and TNFR2 was assessed in T cells, B cells, monocytes, regulatory T cells, T-helper subsets, and cytotoxic T-lymphocyte subsets. Percentages of cells with different co-expression combinations and receptor density per cell were estimated. Longer disease duration was significantly associated with a redistribution of receptors in immunocompetent cell subsets with an increase in the expression of TNFR1 in asthma but did not correlate with significant unidirectional changes in receptor expression in RA. In asthma, a higher proportion of cells with a certain type of TNF receptor (as compared with the healthy group) was correlated with a simultaneous greater density of this receptor type. In RA, an inverse correlation was observed (compensatory lower receptor density). Mechanisms of long-term changes in the expression of TNF receptors differ significantly between the diseases of autoimmune and allergic etiology. The formation of irreversible morphostructural alterations was strongly correlated with changes in the expression of TNFR1 in asthma and with changes in the expression of TNFR2 in RA.

Natural Products Targeting Hsp90 for a Concurrent Strategy in Glioblastoma and Neurodegeneration

Glioblastoma multiforme (GBM) is one of the most common aggressive, resistant, and invasive primary brain tumors that share neurodegenerative actions, resembling many neurodegenerative diseases. Although multiple conventional approaches, including chemoradiation, are more frequent in GBM therapy, these approaches are ineffective in extending the mean survival rate and are associated with various side effects, including neurodegeneration. This review proposes an alternative strategy for managing GBM and neurodegeneration by targeting heat shock protein 90 (Hsp90). Hsp90 is a well-known molecular chaperone that plays essential roles in maintaining and stabilizing protein folding to degradation in protein homeostasis and modulates signaling in cancer and neurodegeneration by regulating many client protein substrates. The therapeutic benefits of Hsp90 inhibition are well-known for several malignancies, and recent evidence highlights that Hsp90 inhibitors potentially inhibit the aggressiveness of GBM, increasing the sensitivity of conventional treatment and providing neuroprotection in various neurodegenerative diseases. Herein, the overview of Hsp90 modulation in GBM and neurodegeneration progress has been discussed with a summary of recent outcomes on Hsp90 inhibition in various GBM models and neurodegeneration. Particular emphasis is also given to natural Hsp90 inhibitors that have been evidenced to show dual protection in both GBM and neurodegeneration.

The complex interactions between the cellular and non-cellular components of the brain tumor microenvironmental landscape and their therapeutic implications

Glioblastoma (GBM), an aggressive high-grade glial tumor, is resistant to therapy and has a poor prognosis due to its universal recurrence rate. GBM cells interact with the non-cellular components in the tumor microenvironment (TME), facilitating their rapid growth, evolution, and invasion into the normal brain. Herein we discuss the complexity of the interactions between the cellular and non-cellular components of the TME and advances in the field as a whole. While the stroma of non-central nervous system (CNS) tissues is abundant in fibrillary collagens, laminins, and fibronectin, the normal brain extracellular matrix (ECM) predominantly includes proteoglycans, glycoproteins, and glycosaminoglycans, with fibrillary components typically found only in association with the vasculature. However, recent studies have found that in GBMs, the microenvironment evolves into a more complex array of components, with upregulated collagen gene expression and aligned fibrillary ECM networks. The interactions of glioma cells with the ECM and the degradation of matrix barriers are crucial for both single-cell and collective invasion into neighboring brain tissue. ECM-regulated mechanisms also contribute to immune exclusion, resulting in a major challenge to immunotherapy delivery and efficacy. Glioma cells chemically and physically control the function of their environment, co-opting complex signaling networks for their own benefit, resulting in radio- and chemo-resistance, tumor recurrence, and cancer progression. Targeting these interactions is an attractive strategy for overcoming therapy resistance, and we will discuss recent advances in preclinical studies, current clinical trials, and potential future clinical applications. In this review, we also provide a comprehensive discussion of the complexities of the interconnected cellular and non-cellular components of the microenvironmental landscape of brain tumors to guide the development of safe and effective therapeutic strategies against brain cancer.