Alzheimer's disease (AD) is a prevalent neurodegenerative disorder. Despite substantial research efforts, our understanding of its pathogenesis remains incomplete, limiting the development of effective treatments and preventive strategies. The potential role of microbial pathogens in AD etiology has gained increasing attention. Various human microbial pathogens have been identified in the brains of AD patients, leading to the pathogen hypothesis, which posits that these microorganisms may disrupt the brain's immune regulation and homeostasis. In this study, we examine the effects of proteins from three pathogens, Borrelia burgdorferi, HSV-1, and Porphyromonas gingivalis, on the aggregation of antimicrobial peptide amyloid-β (Aβ). Three of the four studied proteins were found to attenuate the aggregation of Aβ42 by interacting with its soluble form and inhibiting primary and secondary pathways. These in vitro findings were further supported by experiments using mature neurons derived from human pluripotent stem cells, which showed an increased accumulation of amyloid precursor protein (APP) aggregates upon infection with HSV-1 or exposure to the OspA surface protein from B. burgdorferi. Together, our results provide mechanistic insights into how pathogen-associated proteins modulate Aβ42 aggregation, contributing to an understanding of their potential role in AD pathogenesis.

• Klíčová slova
• Alzheimer’s disease, amyloid-β, amyloids, neuroinflammation, pathogen, virus,
• MeSH
• Alzheimerova nemoc * metabolismus   mikrobiologie   MeSH
• amyloidní beta-protein * metabolismus   MeSH
• amyloidový prekurzorový protein beta metabolismus   MeSH
• bakteriální proteiny * metabolismus   farmakologie   MeSH
• Borrelia burgdorferi metabolismus   MeSH
• lidé MeSH
• lidský herpesvirus 1 metabolismus   MeSH
• neurony metabolismus   účinky léků   MeSH
• peptidové fragmenty * metabolismus   MeSH
• Porphyromonas gingivalis metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• amyloid beta-protein (1-42) MeSH Prohlížeč
• amyloidní beta-protein * MeSH
• amyloidový prekurzorový protein beta MeSH
• bakteriální proteiny * MeSH
• peptidové fragmenty * MeSH

INTRODUCTION: The Pathogen Infection Hypothesis proposes that β-Amyloid (Aβ) functions as an antimicrobial peptide, with pathogen-induced aggregation potentially contributing to Alzheimer's disease (AD) pathology. METHODS: We used human iPSC-derived 2D neurons and 3D cerebral organoids from wild-type and familial AD (PSEN1/2 mutant) lines to model acute infections with HSV-1 and TBEV and Aβ aggregation. Transcriptomic and proteomic analyses were conducted to assess molecular responses. RESULTS: HSV-1, but not TBEV, induced robust Aβ clustering, which was, however, dependent on extracellular amyloid peptides. Transcriptomic profiling revealed widespread HSV-1-induced changes, including activation of neurodegeneration-related pathways. Proteomic profiling confirmed enrichment of neurodegeneration- and senescence-associated secretome signatures. PSEN1/2 mutations did not alter the acute infection response. Reanalysis of independent datasets confirmed our findings and revealed a limited protective effect of acyclovir. DISCUSSION: Results directly support the Pathogen Infection Hypothesis and suggest that preventing viral infections via vaccinations may represent a feasible approach to reducing AD risk.

• Klíčová slova
• Alzheimer’s disease, Cerebral organoids, Herpes virus, Senescence, Tick-borne Encephalitis,
• Publikační typ
• časopisecké články MeSH
• preprinty MeSH

Truncating genetic variants of SORL1, encoding the endosome recycling receptor SORLA, have been accepted as causal of Alzheimer's disease (AD). However, most genetic variants observed in SORL1 are missense variants, for which it is complicated to determine the pathogenicity level because carriers come from pedigrees too small to be informative for penetrance estimations. Here, we describe three unrelated families in which the SORL1 coding missense variant rs772677709, that leads to a p.Y1816C substitution, segregates with Alzheimer's disease. Further, we investigate the effect of SORLA p.Y1816C on receptor maturation, cellular localization, and trafficking in cell-based assays. Under physiological circumstances, SORLA dimerizes within the endosome, allowing retromer-dependent trafficking from the endosome to the cell surface, where the luminal part is shed into the extracellular space (sSORLA). Our results showed that the p.Y1816C mutant impairs SORLA homodimerization in the endosome, leading to decreased trafficking to the cell surface and less sSORLA shedding. These trafficking defects of the mutant receptor can be rescued by the expression of the SORLA 3Fn-minireceptor. Finally, we find that iPSC-derived neurons with the engineered p.Y1816C mutation have enlarged endosomes, a defining cytopathology of AD. Our studies provide genetic as well as functional evidence that the SORL1 p.Y1816C variant is causal for AD. The partial penetrance of the mutation suggests this mutation should be considered in clinical genetic screening of multiplex early-onset AD families.

• Klíčová slova
• 3Fn-domain, SORL1-associated Alzheimer’s disease, SORLA, dimerization, retromer,
• MeSH
• Alzheimerova nemoc * genetika   metabolismus   patologie   MeSH
• endozomy * metabolismus   MeSH
• HEK293 buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové transportní proteiny * genetika   metabolismus   MeSH
• missense mutace MeSH
• multimerizace proteinu MeSH
• proteiny související s LDL-receptory * genetika   metabolismus   MeSH
• rodokmen * MeSH
• senioři MeSH
• transport proteinů MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• membránové transportní proteiny * MeSH
• proteiny související s LDL-receptory * MeSH
• SORL1 protein, human MeSH Prohlížeč

Pleckstrin homology-like domain family A-member 3 (PHLDA3) has recently been identified as a player in adaptive and maladaptive cellular stress pathways. The outcome of pleckstrin homology-like domain family A-member 3 signalling was shown to vary across different cell types and states. It emerges that its expression and protein level are highly increased in amyotrophic lateral sclerosis (ALS) patient-derived astrocytes. Whether it orchestrates a supportive or detrimental function remains unexplored in the context of neurodegenerative pathologies. To directly address the role of pleckstrin homology-like domain family A-member 3 in healthy and ALS astrocytes, we used overexpression and knockdown strategies. We generated cultures of primary mouse astrocytes and also human astrocytes from control and ALS patient-derived induced pluripotent stem cells harbouring the superoxide dismutase 1 mutation. Then, we assessed astrocyte viability and the impact of their secretome on oxidative stress responses in human stem cell-derived cortical and spinal neuronal cultures. Here, we show that PHLDA3 overexpression or knockdown in control astrocytes does not significantly affect astrocyte viability or reactive oxygen species production. However, PHLDA3 knockdown in ALS astrocytes diminishes reactive oxygen species concentrations in their supernatants, indicating that pleckstrin homology-like domain family A-member 3 can facilitate stress responses in cells with altered homeostasis. In support, supernatants of PHLDA3-silenced ALS and even control spinal astrocytes with a lower pleckstrin homology-like domain family A-member 3 protein content could prevent sodium arsenite-induced stress granule formation in spinal neurons. Our findings provide evidence that reducing pleckstrin homology-like domain family A-member 3 levels may transform astrocytes into a more neurosupportive state relevant to targeting non-cell autonomous ALS pathology.

• Klíčová slova
• PHLDA3, amyotrophic lateral sclerosis, astrocyte, astrocyte–neuron interaction, cell stress,
• Publikační typ
• časopisecké články MeSH

Epilepsy is the most common chronic neurological disease, affecting nearly 1%-2% of the world's population. Current pharmacological treatment and regimen adjustments are aimed at controlling seizures; however, they are ineffective in one-third of the patients. Although neuronal hyperexcitability was previously thought to be mainly due to ion channel alterations, current research has revealed other contributing molecular pathways, including processes involved in cellular signaling, energy metabolism, protein synthesis, axon guidance, inflammation, and others. Some forms of drug-resistant epilepsy are caused by genetic defects that constitute potential targets for precision therapy. Although such approaches are increasingly important, they are still in the early stages of development. This review aims to provide a summary of practical aspects of the employment of in vitro human cell culture models in epilepsy diagnosis, treatment, and research. First, we briefly summarize the genetic testing that may result in the detection of candidate pathogenic variants in genes involved in epilepsy pathogenesis. Consequently, we review existing in vitro cell models, including induced pluripotent stem cells and differentiated neuronal cells, providing their specific properties, validity, and employment in research pipelines. We cover two methodological approaches. The first approach involves the utilization of somatic cells directly obtained from individual patients, while the second approach entails the utilization of characterized cell lines. The models are evaluated in terms of their research and clinical benefits, relevance to the in vivo conditions, legal and ethical aspects, time and cost demands, and available published data. Despite the methodological, temporal, and financial demands of the reviewed models they possess high potential to be used as robust systems in routine testing of pathogenicity of detected variants in the near future and provide a solid experimental background for personalized therapy of genetic epilepsies. PLAIN LANGUAGE SUMMARY: Epilepsy affects millions worldwide, but current treatments fail for many patients. Beyond traditional ion channel alterations, various genetic factors contribute to the disorder's complexity. This review explores how in vitro human cell models, either from patients or from cell lines, can aid in understanding epilepsy's genetic roots and developing personalized therapies. While these models require further investigation, they offer hope for improved diagnosis and treatment of genetic forms of epilepsy.

• Klíčová slova
• drug‐resistant epilepsy, genetic testing, in vitro human cell culture, legal and ethical aspects, precision medicine,
• MeSH
• buněčné kultury * MeSH
• epilepsie * genetika   terapie   MeSH
• indukované pluripotentní kmenové buňky MeSH
• lidé MeSH
• neurony metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Primary cilia are key regulators of embryo development and tissue homeostasis. However, their mechanisms and functions, particularly in the context of human cells, are still unclear. Here, we analyzed the consequences of primary cilia modulation for human pluripotent stem cells (hPSCs) proliferation and differentiation. We report that neither activation of the cilia-associated Hedgehog signaling pathway nor ablation of primary cilia by CRISPR gene editing to knockout Tau Tubulin Kinase 2 (TTBK2), a crucial ciliogenesis regulator, affects the self-renewal of hPSCs. Further, we show that TTBK1, a related kinase without previous links to ciliogenesis, is upregulated during hPSCs-derived neural rosette differentiation. Importantly, we demonstrate that while TTBK1 fails to localize to the mother centriole, it regulates primary cilia formation in the differentiated, but not the undifferentiated hPSCs. Finally, we show that TTBK1/2 and primary cilia are implicated in the regulation of the size of hPSCs-derived neural rosettes.

• MeSH
• centrioly metabolismus   MeSH
• cilie metabolismus   MeSH
• lidé MeSH
• pluripotentní kmenové buňky * metabolismus   MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• proteiny hedgehog * genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protein-serin-threoninkinasy MeSH
• proteiny hedgehog * MeSH
• tau-tubulin kinase MeSH Prohlížeč

Defects in DNA repair frequently lead to neurodevelopmental and neurodegenerative diseases, underscoring the particular importance of DNA repair in long-lived post-mitotic neurons1,2. The cellular genome is subjected to a constant barrage of endogenous DNA damage, but surprisingly little is known about the identity of the lesion(s) that accumulate in neurons and whether they accrue throughout the genome or at specific loci. Here we show that post-mitotic neurons accumulate unexpectedly high levels of DNA single-strand breaks (SSBs) at specific sites within the genome. Genome-wide mapping reveals that SSBs are located within enhancers at or near CpG dinucleotides and sites of DNA demethylation. These SSBs are repaired by PARP1 and XRCC1-dependent mechanisms. Notably, deficiencies in XRCC1-dependent short-patch repair increase DNA repair synthesis at neuronal enhancers, whereas defects in long-patch repair reduce synthesis. The high levels of SSB repair in neuronal enhancers are therefore likely to be sustained by both short-patch and long-patch processes. These data provide the first evidence of site- and cell-type-specific SSB repair, revealing unexpected levels of localized and continuous DNA breakage in neurons. In addition, they suggest an explanation for the neurodegenerative phenotypes that occur in patients with defective SSB repair.

• MeSH
• 5-methylcytosin metabolismus   MeSH
• buněčné linie MeSH
• DNA biosyntéza   MeSH
• jednořetězcové zlomy DNA * MeSH
• lidé MeSH
• metylace MeSH
• neurony metabolismus   MeSH
• oprava DNA * MeSH
• poly(ADP-ribosa)polymerasy metabolismus   MeSH
• replikace DNA MeSH
• sekvenční analýza DNA MeSH
• zesilovače transkripce genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• 5-methylcytosin MeSH
• DNA MeSH
• poly(ADP-ribosa)polymerasy MeSH