The inflammation complication: New evidence in cancer-related cognitive impairment

Animal models to study the neurological manifestations of the post-COVID-19 condition

More than 40% of individuals infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have experienced persistent or relapsing multi-systemic symptoms months after the onset of coronavirus disease 2019 (COVID-19). This post-COVID-19 condition (PCC) has debilitating effects on the daily life of patients and encompasses a broad spectrum of neurological and neuropsychiatric symptoms including olfactory and gustative impairment, difficulty with concentration and short-term memory, sleep disorders and depression. Animal models have been instrumental to understand acute COVID-19 and validate prophylactic and therapeutic interventions. Similarly, studies post-viral clearance in hamsters, mice and nonhuman primates inoculated with SARS-CoV-2 have been useful to unveil some of the aspects of PCC. Transcriptomic alterations in the central nervous system, persistent activation of immune cells and impaired hippocampal neurogenesis seem to have a critical role in the neurological manifestations observed in animal models infected with SARS-CoV-2. Interestingly, the proinflammatory transcriptomic profile observed in the central nervous system of SARS-CoV-2-inoculated mice partially overlaps with the pathological changes that affect microglia in humans during Alzheimer's disease and aging, suggesting shared mechanisms between these conditions. None of the currently available animal models fully replicates PCC in humans; therefore, multiple models, together with the fine-tuning of experimental conditions, will probably be needed to understand the mechanisms of PCC neurological symptoms. Moreover, given that the intrinsic characteristics of the new variants of concern and the immunological status of individuals might influence PCC manifestations, more studies are needed to explore the role of these factors and their combinations in PCC, adding further complexity to the design of experimental models.

Glioblastoma cell-derived exosomes induce cell death and oxidative stress in primary cultures of olfactory neurons. Role of redox stress

BACKGROUND

Glioblastoma multiforme, described as glioblastoma, is a malignancy originating from glial progenitors in the central nervous system and is the most malignant subtype of brain tumors which attracted researcher's attention due to their high recurrence and mortality despite optimal treatments. In the study, we aimed to research whether glioblastoma-originated exosomes play a role in olfactory nerve cell toxicity.

METHODS AND RESULTS

For this aim, exosomes obtained from U373 and T98G cells were applied to olfactory nerve cell culture at distinct doses. Then, glutathione (GSH), lactate dehydrogenase (LDH), total antioxidant capacity (TAC), 3-(4,5-Dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT), total oxidant status (TOS) and Immunofluorescence analyzes were performed. We found that both glioblastoma-derived exosomes decreased cell viability in olfactory neurons with increasing doses. According to the obtained data, the olfactory neuron vitality rate was 71% in T98G-exosome, but the decrease in U373-exosome was more obvious (48%). In particular, the 100 µg/ml dose exacerbated oxidative stress by increasing TOS. It also increased cellular apoptosis compared to the control group due to LDH leakage. However, the results of GSH and TAS showed that antioxidant levels were significantly reduced.

CONCLUSION

In the microenvironment of olfactory neurons, GBM-derived exosomes increased oxidative stress-induced toxicity by reducing TAC and GSH levels. Therefore, glioblastoma cells by induction of exosome-based stress support malignant growth.

AVNP2 protects against cognitive impairments induced by C6 glioma by suppressing tumour associated inflammation in rats

Glioblastoma is a kind of malignant tumour and originates from the central nervous system. In the last century, some researchers and clinician have noticed that the psychosocial and neurocognitive functioning of patients with malignant gliomas can be impaired. Many clinical studies have demonstrated that part of patients, adults or children, diagnosed with glioblastoma will suffer from cognitive deficiency during their clinical course, especially in long-term survivors. Many nanoparticles (NPs) can inhibit the biological functions of tumours by modulating tumour-associated inflammation, which provokes angiogenesis and tumour growth. As one of the best antiviral nanoparticles (AVNPs), AVNP2 is the 2nd generation of AVNP2 that have been conjugated to graphite-graphene for improving physiochemical performance and reducing toxicity. AVNP2 inactivates viruses, such as the H1N1 and H5N1influenza viruses and even the SARS coronavirus, while it inhibits bacteria, such as MRSA and E. coli. As antimicrobials, nanoparticles are considered to be one of the vectors for the administration of therapeutic compounds. Yet, little is known about their potential functionalities and toxicities to the neurotoxic effects of cancer. Herein, we explored the functionality of AVNP2 on inhibiting C6 in glioma-bearing rats. The novel object-recognition test and open-field test showed that AVNP2 significantly improved the neuro-behaviour affected by C6 glioma. AVNP2 also alleviated the decline of long-term potentiation (LTP) and the decreased density of dendritic spines in the CA1 region induced by C6. Western blot assay and immunofluorescence staining showed that the expressions of synaptic-related proteins (PSD-95 and SYP) were increased, and these findings were in accordance with the results mentioned above. It revealed that the sizes of tumours in C6 glioma-bearing rats were smaller after treatment with AVNP2. The decreased expression of inflammatory factors (IL-1β, IL-6 and TNF-α) by Western blotting assay and ELISA, angiogenesis protein (VEGF) by Western blotting assay and other related proteins (BDNF, NF-ĸB, iNOS and COX-2) by Western blotting assay in peri-tumour tissue indicated that AVNP2 could control tumour-associated inflammation, thus efficiently ameliorating the local inflammatory condition and, to some extent, inhibiting angiogenesis in C6-bearing rats. In conclusion, our results suggested that AVNP2 could have an effect on the peri-tumor environment, obviously restraining the growth progress of gliomas, and eventually improving cognitive levels in C6-bearing rats.