We cordially invite you to the Ph.D. Seminar, which will be held on March 31, 2023 at 10.30 in the Konorski room. The program includes 4 presentations:
- Mgr Justyna Sekretarska
- Mgr Agnieszka Grabowska
- Mgr Anna Żochowska
- Mgr Diana Legutko
Information regarding speakers together with abstracts can be found below. The seminar will be held in a hybrid mode.
Link to the meeting https://zoom.us/j/96292522633?pwd=VlRPOWUxaDlVMlhiOFpvcnlQdzhOZz09
Anna Filipek & Anna Nowicka
Mgr Justyna Sekretarska
Laboratory of Cytoskeleton and Cilia Biology
Supervisor: Dr. Ewa Joachimiak PhD, DSc
Title: Central pair-associated non-structural proteins in motile cilia motility regulation
Motile cilia skeleton comprises nine outer microtubule doublets and two single, centrally located microtubules, called C1 and C2 that together with docked protein complexes called projections (C1a-f, C1a-e) form a central apparatus (CA). It was estimated that CA is composed of more than 50 proteins, including structural and non-structural proteins containing functional domains. Till now, data concerning the role of the non-structural proteins in cilia behavior are limited. To shed more light on this topic, we used a ciliate Tetrahymena thermophila as a model. We investigated the significance of the known CA protein, Kif9-like kinesin, KLP1, and several phosphorylation-related enzymes, including dual specificity and PP2C phosphatases, MAP kinases and NIMA-related kinase, all identified in our laboratory as potential CA components. The protein-protein interaction studies using BioID, co-immunoprecipitation, and pull-down approaches enabled identification of partners of investigated proteins and to form their interaction map. These biochemical data together with analyses of the engineered knockout mutants’ phenotype led to the conclusion that kinesin Kif9-like and phosphorylation-related enzymes are important part of CA and participate in the proper cilia formation and functioning.
Research supported by NSC grant OPUS15 2018/29/B/NZ3/02443
Mgr Agnieszka Grabowska
Laboratory of Molecular Basis of Cell Motility
Supervisor: Dr. Adriana Magalska, PhD, DSc
Title: Activity-driven chromatin remodeling in neurons is dependent on HDAC1 deacetylase
The study aimed to investigate and develop our understanding of the changes in chromatin organization. The results showed that the induction of long-term potentiation in the in vitro cultured rat hippocampal neurons resulted in the global condensation of the chromatin. The rearrangement in chromatin structure was accompanied by an increase in the level of c-Fos, which belongs to the immediate-early genes. Moreover, the chromatin condensation was accompanied by changes in the localization of the posttranslational modifications of histones and reorganization of the chromosome territories. Using the RNA-seq method, it was possible to discover 931 genes whose expression changed after stimulation in the tested model. Interestingly, after the inhibition of transcription chromatin was still undergoing activity-dependent condensation. The application of the histone deacetylase inhibitors enabled us to find the HDAC1 protein, directly involved in changes in the spatial organization of chromatin. Silencing histone deacetylase 1 showed visible disturbances in the chromatin condensation and its reorganization upon stimulation, which could be reversed by the addback of the human HDAC1 protein.
The activity-driven condensation of the chromatin can have a long-lasting effect on neuronal function and thereby play a significant role in synaptic plasticity, including the processes like, learning and memory formation.
Mgr Anna Żochowska
Laboratory of Language Neurobiology
Supervisor: Prof. Anna Nowicka, PhD, DSc
Title: Prioritized self-referential processing: effects of familiarity and emotional relevance
There is an ongoing debate on the factors driving the prioritized processing of self-referential information. My PhD project aimed to independently investigate the role of the most plausible factors - familiarity and subjective relevance. In the first study, the processing of one’s own face and emotional unknown faces was compared. Multiple methods of EEG data analysis revealed the processing of the self-face is unique and influenced by both aforementioned factors. In a follow-up study, we drew attention to gender differences in the processing of highly familiar and significant faces (self- and close-other’s face) in comparison to unknown faces. Our findings unveiled women better discriminate faces, specifically the self-face from all other faces.
In two other studies, the neural underpinnings of extremely familiar stimuli (self-face, close-other’s face) and stimuli newly assigned to one’s own person and to a close-other (abstract shapes) were investigated. The results of the first study showed the role of subjective significance is crucial and suggested similar attention allocation to both assigned unknown stimuli. Findings from the second study revealed that information referring to the self captures automatically attention in contrast to the information related to the close-other. Thus, the subjective relevance seems to be pivotal in self-prioritization.
Mgr Diana Legutko
Laboratory of Neurobiology
Supervisor I – Prof. Leszek Kaczmarek, PhD, DSc
Supervisor II – Prof. Ryohei Yasuda, Max Planck Florida Institute for Neuroscience, USA
Title: Characterization of Matrix Metalloproteinase 9 involvement in dendritic spines plasticity of hippocampal CA1 pyramidal neurons
Understanding the complex network of molecular interactions underlying morphological and functional synaptic plasticity is a major research challenge. The matrix metalloproteinase-9 (MMP-9) has been repeatedly implicated in plasticity of excitatory synapses, however the kinetics of its action and downstream mechanism is missing.
To gain more insight into this process, we investigated the role of MMP-9 in plastic changes of individual dendritic spines. We used glutamate uncaging protocol to stimulate individual dendritic spines and elicit their long-term structural plasticity. We observed the time of MMP-9 release upon synaptic stimulation and activity of the protease. Moreover, we checked involvement of MMP-9 activity on activation of two tyrosine kinase receptors: TrkB and IGFIR.
Our experiments show MMP-9 is rapidly released, within the first minute of uncaging protocol. Lack of MMP-9 activity, achieved by chemical inhibitors or use of knockout animals, impaired not only spine growth but also caused a decrease in TrkB and IGFIR activation.
The results point to the fundamental role of MMP-9 in dendritic spines plasticity at the onset of long-term potentiation. It is released shortly after uncaging protocol causes activation of neurotrophic factors receptors - TrkB and IGFIR which leads to enlargement of the dendritic spine.