C9orf72-ALS human iPSC microglia are pro-inflammatory and toxic to co-cultured motor neurons via MMP9

• Published in: Nature communications 2023-09, Vol.14 (1), p.5898-5898, Article 5898
• Main Authors: Vahsen, Björn F., Nalluru, Sumedha, Morgan, Georgia R., Farrimond, Lucy, Carroll, Emily, Xu, Yinyan, Cramb, Kaitlyn M. L., Amein, Benazir, Scaber, Jakub, Katsikoudi, Antigoni, Candalija, Ana, Carcolé, Mireia, Dafinca, Ruxandra, Isaacs, Adrian M., Wade-Martins, Richard, Gray, Elizabeth, Turner, Martin R., Cowley, Sally A., Talbot, Kevin
• Format: Article
• Language: English
• Subjects: 13/100; 13/106; 14/19; 38/91; 631/378/1689/1285; 631/378/2596/1953; 631/532/2064/2158; Amyotrophic lateral sclerosis; Amyotrophic Lateral Sclerosis - genetics; C9orf72 Protein - genetics; Cell activation; Cell culture; Chemokines; Coculture Techniques; Gelatinase B; Gene sequencing; Genetic diversity; Genetic variance; Humanities and Social Sciences; Humans; Immune system; Induced Pluripotent Stem Cells; Inflammation; Lipopolysaccharides; Matrix metalloproteinase; Matrix Metalloproteinase 9 - genetics; Matrix metalloproteinases; Metalloproteinase; Microglia; Motor Neurons; multidisciplinary; Mutants; Neurodegenerative Diseases; Neurons; Pathophysiology; Priming; Regulatory sequences; Science; Science (multidisciplinary); Therapeutic targets
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41603-0

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, with additional pathophysiological involvement of non-neuronal cells such as microglia. The commonest ALS-associated genetic variant is a hexanucleotide repeat expansion (HRE) mutation in C9orf72 . Here, we study its consequences for microglial function using human iPSC-derived microglia. By RNA-sequencing, we identify enrichment of pathways associated with immune cell activation and cyto-/chemokines in C9orf72 HRE mutant microglia versus healthy controls, most prominently after LPS priming. Specifically, LPS-primed C9orf72 HRE mutant microglia show consistently increased expression and release of matrix metalloproteinase-9 (MMP9). LPS-primed C9orf72 HRE mutant microglia are toxic to co-cultured healthy motor neurons, which is ameliorated by concomitant application of an MMP9 inhibitor. Finally, we identify release of dipeptidyl peptidase-4 (DPP4) as a marker for MMP9-dependent microglial dysregulation in co-culture. These results demonstrate cellular dysfunction of C9orf72 HRE mutant microglia, and a non-cell-autonomous role in driving C9orf72-ALS pathophysiology in motor neurons through MMP9 signaling. The role of microglia in amyotrophic lateral sclerosis (ALS) is unclear. Here, the authors show that iPSC microglia from C9orf72-ALS patients are toxic to motor neurons and identify microglial MMP9 as a potential therapeutic target.