Astrocyte Gene ATP13A2 Revealed as a Hidden Brake on Brain Inflammation in Parkinson’s Disease

For decades, the hunt for the roots of Parkinson’s disease has focused overwhelmingly on the neurons that die in the midbrain, leaving the brain’s most abundant supporting cells largely in the shadows. A new study published in Frontiers in Cell and Developmental Biology now shifts that spotlight onto astrocytes, the star-shaped glial cells that nourish neurons and police the brain’s inflammatory environment. The research, led by Chen Qiao of Jiangsu University together with colleagues at Jiangnan University and Changzhou, demonstrates that a Parkinson’s-linked gene called ATP13A2 acts as a guardian of mitochondrial health in astrocytes, and that losing it unleashes a cascade of runaway mitochondrial fragmentation, oxidative stress, and inflammatory signaling that may accelerate the disease.

ATP13A2 is no obscure player. Mutations in this gene, which encodes a lysosomal P5-type ATPase, cause Kufor-Rakeb syndrome, a rare autosomal recessive form of parkinsonism. Previous work established that the protein maintains lysosomal integrity and polyamine transport, and that its failure leads to toxic lysosomal accumulation, metal ion imbalance, and impaired clearance of misfolded alpha-synuclein, the protein that clumps into Lewy bodies in Parkinson’s brains. What remained almost entirely unexplored was whether ATP13A2 matters in astrocytes, cells that were long viewed as passive scaffolding but are now recognized as active participants in neurodegeneration. The team’s earlier research had shown that ATP13A2 is highly expressed in astrocytes and modulates neuroinflammation, prompting them to probe deeper.

The investigation began with human data. Mining two publicly available transcriptomic datasets, the researchers found that ATP13A2 expression is significantly reduced in the substantia nigra of Parkinson’s patients, and that the decline grows worse as the disease progresses to advanced Braak stages. An integrative analysis across several neurodegenerative conditions, including Alzheimer’s, Huntington’s, amyotrophic lateral sclerosis, and prion disease, revealed that ATP13A2 shows its strongest association with Parkinson’s disease specifically. In mice poisoned with MPTP, a toxin that recreates key features of parkinsonism, the gene’s message dropped markedly, and Western blotting confirmed a 40.2 percent reduction in ATP13A2 protein in the midbrain, with immunofluorescence showing a 48.3 percent decrease in the substantia nigra pars compacta.

Behavioral testing then revealed what losing the gene does to living animals. Mice engineered to lack Atp13a2, as well as MPTP-treated mice, moved significantly less in the open field test, fell sooner from an accelerating rotarod, and took longer to orient and descend a vertical pole. These motor deficits were mirrored by striking neurodegeneration: Nissl staining showed a 41 percent loss of neurons in the substantia nigra pars compacta of knockout mice, tyrosine hydroxylase staining revealed a 48.9 percent loss of dopaminergic neurons, and striatal dopamine fiber density fell by 28.8 percent. High-performance liquid chromatography confirmed depleted striatal levels of dopamine and its metabolites DOPAC and homovanillic acid, painting a coherent picture of a compromised nigrostriatal pathway.

The pivotal discovery came when the team turned to the mitochondria inside astrocytes. Transmission electron microscopy of midbrain tissue from knockout mice revealed pronounced mitochondrial fragmentation, with organelles shrinking in area and showing swelling and disrupted cristae, the internal folds where energy production occurs. Gene set enrichment analysis of RNA sequencing data pointed to disturbed astrocyte development and mitochondrial processes, and immunofluorescence showed a marked surge of GFAP-positive activated astrocytes in the injured midbrain. Critically, ATP13A2 protein was found to spatially overlap with TIM23, a marker of the mitochondrial inner membrane, and with Drp1, the master regulator of mitochondrial fission, hinting that the gene’s influence extends beyond the lysosome.

Western blot analysis of midbrain tissue confirmed a lopsided fission-fusion balance. Proteins that drive mitochondrial division, including Drp1, its activated Ser616-phosphorylated form, and the fission adaptor Fis1, were all upregulated, while fusion proteins OPA1, Mfn1, and Mfn2 were downregulated. Double labeling showed that Drp1 accumulation occurred predominantly within GFAP-positive astrocytes, linking the fission surge directly to reactive glia. In primary astrocytes cultured from knockout mice, the mitochondrial superoxide probe MitoSOX revealed oxidative stress on par with that produced by MPP-plus, the toxic metabolite of MPTP, indicating that the gene loss alone is sufficient to push astrocytic mitochondria into a dysfunctional, redox-imbalanced state.

To dissect the mechanism in a controlled setting, the researchers used the C8-D1A astrocyte cell line and lentiviral tools to knock down or restore Atp13a2. Knockdown reproduced the in vivo signature: elevated Drp1, Fis1, and p-Drp1, reduced OPA1 and Mfn2, collapsed mitochondrial membrane potential measured by both JC-1 and TMRM probes, and elevated reactive oxygen species quantified by flow cytometry. Treating the cells with Mdivi-1, a pharmacological inhibitor of mitochondrial division, normalized several of these defects without restoring ATP13A2 itself, placing the fission machinery downstream of the gene. Conversely, lentiviral overexpression of Atp13a2 reversed the fission protein surge, restored membrane potential, and proved even more effective than Mdivi-1 at rescuing Mfn2 expression, suggesting that reconstituting the gene corrects the fission-fusion imbalance more comprehensively than blocking fission alone.

Perhaps the most consequential finding concerns inflammation. Atp13a2-deficient astrocytes released significantly more double-stranded DNA into their surroundings, accompanied by increased DNASE2 protein levels, and secreted elevated amounts of the pro-inflammatory cytokines IL-1 beta, IL-6, and TNF-alpha as measured by ELISA. Both Mdivi-1 treatment and Atp13a2 overexpression suppressed the DNA release and the cytokine flood. Extracellular DNA is a well-known danger signal that can ignite innate immune pathways such as NLRP3 inflammasome activation and cGAS-STING signaling, although the authors are careful to note that their PicoGreen assay measured total extracellular DNA without establishing its mitochondrial origin, and that defining the precise inflammatory pathway will require future work with mitochondrial DNA-specific assays.

The study’s authors frame their results within a triple synergistic model of Parkinson’s progression, in which ATP13A2 loss disrupts lysosomal-mitochondrial homeostasis, damaged astrocytic mitochondria fuel oxidative and inflammatory cascades, and the resulting neurotoxic glial environment feeds back to accelerate dopaminergic neuron death. They also acknowledge important limitations: the global knockout model cannot prove astrocyte-specific causality, the acute MPTP model does not fully recapitulate chronic alpha-synuclein pathology, and fluorescence colocalization indicates proximity rather than direct physical interaction between ATP13A2 and the fission machinery. Even so, the demonstration that a single Parkinson’s-linked gene governs the fission-fusion equilibrium in astrocytes, and that pharmacological fission inhibition can dampen the inflammatory fallout, opens a concrete therapeutic avenue. If future studies with astrocyte-specific conditional knockouts and complementary disease models confirm the mechanism, drugs that stabilize mitochondrial dynamics in glia could one day slow a disease that current treatments can only symptomatically manage.

Subject of Research: The role of astrocytic ATP13A2 in regulating mitochondrial fission and neuroinflammation in Parkinson's disease

Article Title: Astrocytic ATP13A2 modulates neuroinflammatory responses via mitochondrial fission in Parkinson’s disease

Article References: Astrocytic ATP13A2 modulates neuroinflammatory responses via mitochondrial fission in Parkinson’s disease. (n.d.). https://doi.org/10.3389/fcell.2026.1959910

Image Credits: AI Generated

DOI: 10.3389/fcell.2026.1959910

Keywords: Parkinson's disease, ATP13A2, astrocytes, mitochondrial fission, Drp1, neuroinflammation, reactive oxygen species, Mdivi-1, substantia nigra, cytokines, MPTP model, neurodegeneration