MB12501) following the manufacturers instructions
MB12501) following the manufacturers instructions. SAG at 1 M. 12974_2022_2442_MOESM1_ESM.docx (165K) GUID:?13526DE3-052F-4EFF-A099-40889AE636B1 Data Availability StatementAll data used and analyzed for the current study are available from the corresponding author on reasonable request. Abstract Background Friedreichs ataxia is a rare hereditary neurodegenerative disease caused by decreased levels of the mitochondrial protein frataxin. Similar to other neurodegenerative pathologies, previous studies suggested that astrocytes might contribute to the progression of the disease. To fully understand the mechanisms underlying neurodegeneration in Friedreichs ataxia, we investigated the reactivity status and functioning of cultured human astrocytes after frataxin depletion using an RNA interference-based approach and tested the effect of pharmacologically modulating the SHH pathway as a novel neuroprotective strategy. Results We observed loss of cell viability, mitochondrial alterations, increased autophagy and lipid accumulation in cultured astrocytes upon frataxin depletion. Besides, frataxin-deficient cells show higher expression of several A1-reactivity markers and release of pro-inflammatory cytokines. Interestingly, most of these defects were prevented by chronically treating the cells with the smoothened agonist SAG. Furthermore, in vitro culture of neurons with conditioned medium from frataxin-deficient astrocytes results in a reduction of neuronal survival, neurite length Chebulinic acid and synapse formation. However, when frataxin-deficient astrocytes were chronically treated with SAG, we did not observe these alterations in neurons. Conclusions Our results demonstrate that the pharmacological activation of the SHH pathway could be used as a target to modulate astrocyte reactivity and neuronCglia interactions to prevent neurodegeneration in Friedreichs ataxia. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02442-w. gene, causing a significant reduction in the transcription levels of the mitochondrial protein frataxin (FXN) [3]. Classically, the study of the pathophysiology of neurodegenerative diseases has been focused on untangling the processes and molecular mechanisms where neurons are involved. However, significant evidence has demonstrated the important role that glial cells have as active contributors to the neurodegenerative process associated with different neurodegenerative diseases [4C8]. Among all glial cells, astrocytes constitute a high percentage of cells in the mammalian central nervous system (CNS), providing trophic support to neurons, promoting synapse Agt formation and functioning, protecting neurons against oxidative stress and participating in the propagation of action potentials [9, 10]. These functions are executed mainly by secreted proteins, which means that astrocytes and neurons are in constant communication. Even so, as these cells are essential for CNS homeostasis, they are also key players Chebulinic acid in brain dysfunction [11C13]. In response to different stimuli, astrocytes undergo a process called reactive astrocytosis, having important changes in gene expression and functionality [14]. Neuroinflammation and ischemia induce the formation of at least two types of reactive astrocytes, the pro-inflammatory and neurotoxic astrocytic Chebulinic acid phenotype A1, and the neuroprotective astrocytic phenotype A2. A1-reactive astrocyte formation is triggered by the release of a cytokine cocktail from activated microglia, comprising interleukin 1 alpha (IL-1), tumor necrosis factor alpha (TNF-) and the complement component C1q [14]. Blocking the release of these cytokines has been observed to be neuroprotective in different models of Parkinsons disease and retinal injury [15, 16]. Importantly, A1-reactive astrocytes are present in post-mortem tissues from patients with different neuroinflammatory and neurodegenerative diseases and in in vitro models of neuroinflammatory conditions, which suggests that they might have a crucial role in the neuropathology of these diseases [14, 15, 17C20]. In FRDA, some works using in vivo models of Chebulinic acid silencing in glial cells have shown that this protein is essential for cell survival and neuronal functioning. In the specific knockdown of in glial cells generates a similar phenotype to the one observed after silencing ubiquitously: increased neuronal degeneration, altered locomotor activity and reduced lifespan [21]. Moreover, we previously reported that human astrocytes (HAs) with reduced FXN levels have decreased viability and proliferation, and released soluble factors that altered astrocyteCneuron cross talk and cause neuronal toxicity [22]. Still, Chebulinic acid an in-depth characterization.