Investigação do efeito do canabidiol sobre a reatividade em astrócitos humanos derivados de células-tronco de pluripotência induzida (iPSCs)

Abstract

Astrocytes are the most abundant glial cells and perform essential functions contributing for brain homeostasis and synaptic plasticity. In response to extrinsic signals, such as inflammatory mediators, astrocytes undergo transcriptional, morphological and functional modifications, in a process known as reactive astrogliosis or astrocytic reactivity. According to the adopted phenotype, reactivity can contribute to the maintenance or resolution of pathological conditions, making astrocytes potential pharmacological targets for the treatment of neurological diseases. In recent years, it has been shown that cannabidiol exerts modulatory effects on astrocyte activation in animal models. However, the investigation of its effects on human astrocytes is still quite scarce due to the difficulty in obtaining cells from the human central nervous system. Recently, the development of induced pluripotency stem cells (iPSCs) has arrised as an alternative to overcome this obstacle, facilitating the obtainment of different human cell types. Therefore, the present study aimed to verify whether cannabidiol exerts immunomodulation on human astrocytes, as already demonstrated in rodent astrocytes. For this, we analyzed the in vitro effects of cannabidiol on molecular and functional parameters of human astrocytes, as well as its potential to modulate the astrocytic response to the inflammatory cytokines interleukin 1 beta (IL- 1β) and tumor necrosis factor alpha (TNF-α). The results indicate that the inflammatory stimulus increased the production of IL-1β and TNF-α by astrocytes. However, it did not alter the expression of interleukin 6 (IL-6), brain-derived neurotrophic factor (BDNF), progranulin protein and excitatory amino acid transport 1 (EAAT1). Furthermore, the inflamatory insult did not change the extracellular concentration of glutamate in astrocytic cultures. Treatment with cannabidiol inhibited the increase of IL-1β in stimulated astrocytes, but it did not change the other parameters analyzed in quiescent and stimulated astrocytes. Cell viability assay indicated that cannabidiol at the concentration of 10 μM, but not 1 μM, triggered astrocytic cell death. Taken together, these data point to the importance of more detailed investigations into the action of cannabidiol on human cells of the central nervous system, in view of its use in the treatment of neuroinflammatory conditions.