Biology subjects

Janeckova, L.

Publications and source records attributed to Janeckova, L..

5 recordsLinked to original sources

bioRxiv2023

Astrocyte-like subpopulation of NG2 glia in the adult mouse cortex exhibits characteristics of neural progenitor cells and is capable of forming neuron-like cells after ischemic injury

Glia cells expressing neuron-glial antigen 2 (NG2) play a critical role as oligodendrocyte precursor cells (OPCs) in the healthy brain; however, their differentiation potential after ischemic injury remains an unresolved question. Here, we aimed to elucidate the heterogeneity and role of NG2 glia in the ischemic brain. We used transgenic mice to label NG2-expressing cells and their progeny with red fluorescent protein tdTomato in the healthy brains and those after focal cerebral ischemia (FCI). Based on single-cell RNA sequencing, the labeled glial cells were divided into five distinct subpopulations. The identity of these subpopulations was determined based on gene expression patterns. In addition, membrane properties were further analyzed using the patch-clamp technique. Three of the observed subpopulations represented OPCs, whereas the fourth group exhibited characteristics of cells destined for oligodendrocyte fate. The fifth subpopulation of NG2 glia carried astrocytic markers. Importantly, we detected features of neural progenitors in these cells. This subpopulation was present in both healthy and post-ischemic tissue; however, its gene expression changed after ischemia, with genes related to neurogenesis being more abundant. Neurogenic gene expression was monitored over time and complemented by immunohistochemical staining, which showed increased numbers of Purkinje cell protein 4-positive NG2 cells at the edge of the ischemic lesion 12 days after FCI, and NeuN-positive NG2 cells 28 days after injury, indicating the existence of neuron-like cells that develop from NG2 glia in the ischemic tissue. Our results provide further insight into the differentiation plasticity and neurogenic potential of NG2 glia after stroke. Main PointsO_LIDifferent subpopulations of NG2 glia in the healthy and ischemic adult cortex were identified based on their gene expression and membrane properties. C_LIO_LIAstrocyte-like NG2 glia exhibit neurogenic gene expression and are more abundant in post-ischemic tissue. C_LIO_LIProgeny of NG2-positive cells carrying neuronal marker NeuN was observed at the edge of the ischemic lesion. C_LI

neuroscience↗

bioRxiv2022

TROP2 represents a negative prognostic factor in colorectal adenocarcinoma and its expression is associated with features of epithelial-mesenchymal transition and invasiveness

Trophoblastic cell surface antigen 2 (TROP2) is a membrane glycoprotein overexpressed in many solid tumors with poor prognosis, including intestinal neoplasms. In our study, we show that TROP2 is expressed in preneoplastic lesions and its expression is maintained in most colorectal cancer (CRC). High TROP2 positivity correlated with lymph node metastases and poor tumor differentiation and was a negative prognostic factor. To investigate the role of TROP2 in intestinal tumors, we analyzed two mouse models with conditional disruption of the adenomatous polyposis coli (Apc) tumor suppressor gene, human adenocarcinoma samples, patient-derived organoids, and TROP2-deficient tumor cells. We found that Trop2 is produced early after Apc inactivation and its expression is associated with transcription of genes involved in epithelial-mesenchymal transition, regulation of migration, invasiveness, and extracellular matrix remodeling. A functionally similar group of genes was also enriched in TROP2-positive cells from human CRC samples. To decipher the driving mechanism of TROP2 expression, we analyzed its promoter. In human cells, this promoter was activated by {beta}-catenin and additionally by Yes1-associated transcriptional regulator (YAP). The regulation of TROP2 expression by active YAP was verified by YAP knockdown in CRC cells. Our results suggest a possible link between aberrantly activated Wnt/{beta}-catenin signaling, YAP, and TROP2 expression. Simple SummaryColorectal cancer (CRC) is one of the most common cancers worldwide. While systemic treatment of CRC is based on chemotherapy, subsequent therapeutic options are far less effective. Trophoblast cell surface antigen 2 (TROP2) is highly expressed in many carcinomas, including CRC, where its expression correlates with poor prognosis. Anti-TROP2-targeted therapy was approved for the treatment of breast and urothelial carcinomas. We aimed to determine whether TROP2 is a suitable target for the treatment of CRC. We demonstrated that TROP2 expression in CRC correlates with lymph node metastasis and poor tumor differentiation. Analysis of mouse tumor models, patient-derived organoids, and tumor cells revealed that TROP2 expression is associated with features related to epithelial-mesenchymal transition and invasiveness. Our results suggest that TROP2 targeting may be a promising approach, especially in the early phase of treatment.

cancer biology↗

bioRxiv2022

Tumor suppressor Hypermethylated in Cancer 1 represses expression of cell cycle regulator E2F7 in human primary cells

Hypermethylated in Cancer 1 (HIC1) is an established tumor suppressor, which is frequently inactivated in various cancers. In colorectal carcinoma (CRC), silencing of HIC1 has been recognized as one of the important events in malignant tumor progression. Strikingly, CRC patients with high HIC1 expression have a worse prognosis than patients with relatively low HIC1 mRNA levels. To analyze the function of HIC1, we performed expression profiling of human primary fibroblasts after downregulation of HIC1 by RNA interference. We show that HIC1 deficiency triggers a p53-dependent response and that disruption of the HIC1 gene in human colon cells delays cell cycle progression under serum deficiency conditions. Moreover, treatment with etoposide, a DNA-damaging agent, significantly impairs the proliferation rate and dynamics of damaged DNA repair in HIC1-deficient compared with wild-type cells. One of the genes upregulated in HIC1-depleted cells encodes cell cycle regulator E2F7. E2F7 is an atypical member of the E2F family, which functions primarily as a transcriptional repressor, and its downregulation is essential for proper cell cycle progression and expression of genes involved in DNA repair. We demonstrated that E2F7 is indeed the target of transcriptional repression mediated by HIC1. Moreover, our results suggest that the phenotypic manifestations associated with loss of the HIC1 gene, in particular the changes in cell cycle progression and slowed repair of damaged DNA, are caused by dysregulation of E2F7 expression. Finally, we observed an inverse relationship between HIC1 and E2F7 in a panel of CRC. Importantly, CRC patients who express relatively high levels of E2F7 have a remarkably better prognosis than patients with intermediate or low levels of E2F7 expression.

cancer biology↗

bioRxiv2022

Natural language signatures of psilocybin microdosing

Serotonergic psychedelics are being studied as novel treatments for mental health disorders and as facilitators of improved well-being, mental function and creativity. Recent studies have found mixed results concerning the effects of low doses of psychedelics ("microdosing") on these domains. However, microdosing is generally investigated using instruments designed to assess larger doses of psychedelics, which might lack sensitivity and specificity for this purpose. Following a double-blind and placebo-controlled experimental design, we explored natural language as a resource to identify speech produced under the acute effects of psilocybin microdoses, focusing on variables known to be affected by higher doses: verbosity, semantic variability and sentiment scores. Except for semantic variability, these metrics presented significant differences between a typical active microdose of 0.5 g of psilocybin mushrooms and an inactive placebo condition. Moreover, machine learning classifiers trained using these metrics were capable of distinguishing between conditions with high accuracy (AUC{approx}0.8). Our results constitute first proof that low doses of serotonergic psychedelics can be identified from unconstrained natural speech, with potential for widely applicable, affordable, and ecologically valid monitoring of microdosing schedules.

pharmacology and toxicology↗

bioRxiv2021

Microevidence for microdosing with psilocybin mushrooms: a double-blind placebo-controlled study of subjective effects, behavior, creativity, perception, cognition, and brain activity

The use of low sub-hallucinogenic doses of psychedelics ("microdosing") has gained popularity in recent years. Although anecdotal reports claim multiple benefits associated with this practice, the lack of placebo-controlled studies limits our knowledge of microdosing and its effects. Moreover, research conducted in laboratory settings might fail to capture the motivation of individuals engaged in microdosing protocols. We recruited 34 individuals planning to microdose with psilocybin mushrooms (Psilocybe cubensis), one of the materials most frequently used for this purpose. Following a double-blind placebo-controlled design, we investigated the effects of 0.5 g dried mushrooms on subjective experience, behavior, creativity, perception, cognition, and brain activity. The reported acute effects were significantly more intense for the active dose compared to the placebo, which could be explained by unblinding. For the other measurements, we observed either null effects or a trend towards cognitive impairment and, in the case of EEG, towards reduced theta band spectral power. Our findings support the possibility that expectation effects underlie at least some of the anecdotal benefits attributed to microdosing with psilocybin mushrooms.

neuroscience↗