MS‐Driven Metabolic Alterations Are Recapitulated in iPSC‐Derived Astrocytes

Abstract

Objective: Astrocytes play a significant role in the pathology of multiple sclerosis (MS). Nevertheless, for ethical reasons, most studies in these cells were performed using the Experimental Autoimmune Encephalomyelitis model. As there are significant differences between human and mouse cells, we aimed here to better characterize astrocytes from patients with MS (PwMS), focusing mainly on mitochondrial function and cell metabolism. Methods: We obtained and characterized induced pluripotent stem cell (iPSC)-derived astrocytes from three PwMS and three unaffected controls, and performed electron microscopy, flow cytometry, cytokine and glutamate measurements, gene expression, in situ respiration, and metabolomics. We validated our findings using a single-nuclei RNA sequencing dataset. Results: We detected several differences in MS astrocytes including: (i) enrichment of genes associated with neurodegeneration, (ii) increased mitochondrial fission, (iii) increased production of superoxide and MS-related proinflammatory chemokines, (iv) impaired uptake and enhanced release of glutamate, (v) increased electron transport capacity and proton leak, in line with the increased oxidative stress, and (vi) a distinct metabolic profile, with a deficiency in amino acid catabolism and increased sphingolipid metabolism, which have already been linked to MS. Interpretation: Here we describe the metabolic profile of iPSC-derived astrocytes from PwMS and validate this model as a very powerful tool to study disease mechanisms and to perform non-invasive drug targeting assays in vitro. Our findings recapitulate several disease features described in patients and provide new mechanistic insights into the metabolic rewiring of astrocytes in MS, which could be targeted in future therapeutic studies.

Increased Cholesterol Synthesis Drives Neurotoxicity in Patient Stem Cell-Derived Model of Multiple Sclerosis

“…Our current findings suggest that PMS iNSCs sustain a hypermetabolic state, associated with increased glycolysis and oxidative phosphorylation (OXPHOS). Similar results have been reported in erythrocytes 21 , fibroblasts 22,61 , and astrocytes 17 of MS patients and in senescent cells 23 , without the identification of a clear function of this metabolic state in a pathophysiological context yet.…”

Research progress of autoimmune diseases based on induced pluripotent stem cells

“…However, Ghirotto et al. found that MS-iPSCs-derived astrocytes could impair the uptake and enhance the release of glutamate ( 47 ). Notablely, Ghirotto et al.…”

Integrative single-cell analysis of neural stem/progenitor cells reveals epigenetically dysregulated interferon response in progressive multiple sclerosis

“…17,24 Furthermore, iPSC-astrocytes from MS patients also display senescence-related gene expression, dysfunctional metabolism, and increased immune and inflammatory genes. 25,26 Stem cell exhaustion is a known hallmark of biological aging that is typically associated with reduced tissue repair. Adult brain stem cells/NSCs, also known as radial glia-like cells (RG), are astroglial-like cells that classically reside in the mammalian subventricular zone and dentate gyrus of the hippocampus and can give rise to mature neurons, astrocytes, and oligodendrocytes.…”

“…We employed the use of direct reprogramming technology, which better retains epigenetic memory of the donor cells, 44 to better investigate the origin of the senescent phenotype in NSCs within the context of PMS. 17,24,25 , We directly converted skin-derived fibroblasts from healthy human controls and people with PMS into stably expandable induced NSCs (iNSC). This was done by exposing fibroblasts to a transient (24-hour long) exposure to the Yamanaka factors 45 in the presence of NSC differentiation factors to generate a heterogenous population of stem and progenitor cells.…”

“…17,24 Furthermore, iPSC-astrocytes from MS patients also display senescence-related gene expression, dysfunctional metabolism, and increased immune and inflammatory genes. 25,26…”