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Dysregulated microglia activation, leading to neuroinflammation, is crucial in neurodegenerative disease development and progression. We constructed an atlas of human brain immune cells by integrating nineteen single-nucleus RNA-seq and single-cell RNA-seq datasets from multiple neurodegenerative conditions, comprising 241 samples from patients with Alzheimer's disease, autism spectrum disorder, epilepsy, multiple sclerosis, Lewy body diseases, COVID-19, and healthy controls. The integrated Human Microglia Atlas (HuMicA) included 90,716 nuclei/cells and revealed nine populations distributed across all conditions. We identified four subtypes of disease-associated microglia and disease-inflammatory macrophages, recently described in mice, and shown here to be prevalent in human tissue. The high versatility of microglia is evident through changes in subset distribution across various pathologies, suggesting their contribution in shaping pathological phenotypes. A GPNMB-high subpopulation was expanded in AD and MS. In situ hybridization corroborated this increase in AD, opening the question on the relevance of this population in other pathologies., Competing Interests: Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Microglia play a crucial role in a range of neuropathologies through exacerbated activation. Microglial inflammatory responses can be influenced by prior exposures to noxious stimuli, like increased levels of extracellular adenosine and ATP. These are characteristic of brain insults like epileptic seizures and could potentially shape subsequent responses through epigenetic regulation. We investigated DNA methylation and expression changes in human microglia-like cells differentiated from monocytes following ATP-mediated preconditioning. We demonstrate that microglia-like cells display homeostatic microglial features, shown by surface markers, transcriptome, and DNA methylome. After exposure to ATP, TLR-mediated activation leads to an exacerbated pro-inflammatory response. These changes are accompanied by methylation and transcriptional reprogramming associated with enhanced immune-related functions. The reprogramming associated with ATP-mediated preconditioning leads to profiles found in microglial subsets linked to epilepsy. Purine-driven microglia immune preconditioning drives epigenetic and transcriptional changes that could contribute to altered functions of microglia during seizure development and progression., Competing Interests: The authors declare no competing interests., (© 2024 The Author(s).)

Background: Apolipoprotein E (ApoE) is the main lipoprotein secreted in brain. It has a critical immunomodulatory function, influences neurotransmission and it is involved in repairing damaged neurons. ApoE e4 is an isoform of ApoE with altered function, and was previously associated with early onset epilepsy and refractoriness, both in animal models and in patients with focal epilepsies. There is a limited knowledge on ApoE's role in Genetic Generalized Epilepsies (GGE). Aim: To determine if ApoE isoforms are risk factors for GGE development. Methods: A group of 337 GGE patients (193 F, 144 M, 33.6 ± 14.2 years) was compared with a group of 342 healthy individuals in a case-control genetic association study. ApoE genotyping was performed using PCR-RFLP. Results: The genotypic frequency of ApoE e3/e2 was lower in GGE patients relative to controls (6.5% in GGE vs. 11.7% in controls, p  = 0.019, OR (95% CI) = 0.53 (0.305-0.905). No associations with other clinical data such as photosensitivity or age at disease onset were observed. Conclusion: Our results show that ApoE e3/e2 genotype may be a protective factor for GGE development. There is evidence that this genotype could be neuroprotective, preventing oxidative damage and promoting neuronal survival. Although replication studies are warranted, our data suggest that ApoE isoforms have a role in epileptogenic mechanisms regardless of the specific epileptic manifestations.

Familial amyloidotic polyneuropathy, ATTRV30M (p. TTRV50M) amyloidosis, is a neurodegenerative disease characterized by systemic extracellular amyloid deposition of a mutant transthyretin, TTR V30M. Anemia, with low erythropoietin (EPO) levels and spared kidney function, affects about 25% of symptomatic patients, suggesting a blockage of EPO-producing cells. Early non-fibrillar TTR aggregates are highly cytotoxic, inducing oxidative stress, the expression of apoptosis-related molecules and secretion of pro-inflammatory cytokines, factors capable of inhibiting EPO production. Low EPO levels in these patients are not related to renal amyloid deposition or the presence of circulating TTR V30M. However, the role of early non-fibrillar TTR aggregates remains unexplored. We used the EPO producing Hep3B human hepatoma cell line to study the effect of TTR oligomeric aggregates on EPO expression. Hep3B cells were incubated with soluble and oligomeric TTR V30M, and cell proliferation as well as caspase 3/7 activation was evaluated. Relative quantification of EPO mRNA transcripts was performed by real-time PCR. Significant reductions in cell viability (13 ± 7.3%) and activation of caspases 3/7 were seen after 24 h in the presence of oligomeric TTR V30M. Also, EPO expression was significantly reduced (50 ± 2.8%), in normoxic conditions. A reporter assay was constructed with a PCR fragment of the EPO promoter linked to the luciferase gene to evaluate the role of transcription factors targeting the promoter. A significant reduction of EPO promoter activity (53 ± 6.5%) was observed in transfected cells exposed to TTR oligomers. Our results show that oligomeric TTR V30M reduces EPO expression, at least in part through inhibition of promoter activity.

Introduction: Behçet's disease (BD) is a multisystem inflammatory disease of unknown etiology that may affect the CNS - Neuro-Behçet (NB). Our aim was to evaluate the frequency of neurological involvement and characterize a cohort of our NB patients., Methods: We retrospectively revised the clinical, laboratory and imaging data of a cohort of BD patients, followed in our hospital outpatient clinic., Results: We identified 138 BD patients. Twenty-five out of 138 had NB (15 female). Four patients presented with neurological symptoms. We identified a total of 37 attacks. Twenty-one attacks were classified as parenchymatous, four non-parenchymatous and 12 as other syndromes. Seventeen patients had CSF analysis performed (20 samples). Five samples were normal, 15 showed CSF pleocytosis. The most frequent finding on MRI performed in the acute phase was extensive lesions involving the brainstem. Two patients died due to the neurological involvement of BD., Conclusion: We found 18.1% prevalence of NB and a higher female-to-male ratio in our group than in other series. Gastrointestinal and vascular involvement was more frequent in the NB group. The fact that neurological involvement may be the first manifestation of BD with therapeutic implications and associated morbidity points out the relevance of an early diagnosis., (© 2015 S. Karger AG, Basel.)