Driver mutations of pancreatic cancer affect Ca2+Ca^{2+} signaling and ATP production

Glandular pancreatic epithelia of the acinar or ductal phenotype may seem terminally differentiated, but they are characterized by remarkable cell plasticity. Stress-induced trans-differentiation of these cells has been implicated in the mechanisms of carcinogenesis. Current consensus links pancreatic ductal adenocarcinoma with onco-transformation of ductal epithelia, but under the presence of driver mutations in Kras and Trp53, also with trans-differentiation of pancreatic acini. However, we do not know when, in the course of cancer progression, physiological functions are lost by mutant acinar cells, nor can we assess their capacity for the production of pancreatic juice components. Here, we investigated whether two mutations—$Kras^{G12D}$ and $Trp53^{R172H}$—present simultaneously in acinar cells of KPC mice (model of oncogenesis) influence cytosolic Ca2+ signals. Since $Ca^{2+}$ signals control the cellular handling of digestive hydrolases, any changes that affect intracellular signaling events and cell bioenergetics might have an impact on the physiology of the pancreas. Our results showed that physiological doses of acetylcholine evoked less regular $Ca^{2+}$ oscillations in KPC acinar cells compared to the control, whereas responses to supramaximal concentrations were markedly reduced. Menadione elicited $Ca^{2+}$ signals of different frequencies in KPC cells compared to control cells. Finally, $Ca^{2+}$ extrusion rates were significantly inhibited in KPC cells, likely due to the lower basal respiration and ATP production. Cumulatively, these findings suggest that driver mutations affect the signaling capacity of pancreatic acinar cells even before the changes in the epithelial cell morphology become apparent

Thymic epithelial cell fate and potency in early organogenesis assessed by single cell transcriptional and functional analysis

During development, cortical (c) and medullary (m) thymic epithelial cells (TEC) arise from the third pharyngeal pouch endoderm. Current models suggest that within the thymic primordium most TEC exist in a bipotent/common thymic epithelial progenitor cell (TEPC) state able to generate both cTEC and mTEC, at least until embryonic day 12.5 (E12.5) in the mouse. This view, however, is challenged by recent transcriptomics and genetic evidence. We therefore set out to investigate the fate and potency of TEC in the early thymus. Here using single cell (sc) RNAseq we identify a candidate mTEC progenitor population at E12.5, consistent with recent reports. Via lineage-tracing we demonstrate this population as mTEC fate-restricted, validating our bioinformatics prediction. Using potency analyses we also establish that most E11.5 and E12.5 progenitor TEC are cTEC-fated. Finally we show that overnight culture causes most if not all E12.5 cTEC-fated TEPC to acquire functional bipotency, and provide a likely molecular mechanism for this changed differentiation potential. Collectively, our data overturn the widely held view that a common TEPC predominates in the E12.5 thymus, showing instead that sublineage-primed progenitors are present from the earliest stages of thymus organogenesis but that these early fetal TEPC exhibit cell-fate plasticity in response to extrinsic factors. Our data provide a significant advance in the understanding of fetal thymic epithelial development and thus have implications for thymus-related clinical research, in particular research focussed on generating TEC from pluripotent stem cells

Identification of endothelial subsets involved in interactions with hematopoietic stem cells in bone marrow niche based on single cell RNA sequencing

W organizmie wszystkie komórki krwi wywodzą się z rzadkiej populacji hematopoetycznych komórek macierzystych (ang. HSC). Ważną rolę w podtrzymaniu i regulowaniu funkcjonowania HSC odgrywa niszą hematopoetyczną– wyspecjalizowana, heterogenna grupa komórek tworząca ich mikrośrodowisko w szpiku kostnym. Pomimo intensywnych badań prowadzonych w tej dziedzinie wciąż brak konsensusu co do dokładnej budowy i położenia niszy. Obecnie większość badań wspiera istnienie niszy przynaczyniowej, której istotną częścią są komórki śródbłonka (ang. Endothelial cells, ECs). Nie ma jednak zgody co do rodzaju naczyń, przy których ma się ona znajdować. Z tego powodu celem pracy była identyfikacja frakcji ECs uczestniczących w tworzeniu niszy hematopoetycznej.Założyliśmy, że frakcja ECs budująca niszę hematopoetyczną oddziałuje z komórkami HSC i multipotencjalnymi komórkami progenitorowycmi (ang. MPP) na drodze specyficznych interakcji molekularnych, które można wskazać na podstawie danych z sekwencjonowania RNA pojedynczych komórek. Wykorzystaliśmy dane ECs uzyskane przez trzy niezależne zespoły badawcze.Komórki podejrzewane o interakcje z poszczególnymi typami komórek hematopoetycznych zostały wytypowane na podstawie ilości pojedynczych interakcji molekularnych pomiędzy tymi komórkami. Informacja o interakcjach molekularnych pochodziła z ręcznie potwierdzonej bazy odziaływań pomiędzy receptorami błonowymi a ligandami błonowymi, wydzielniczymi i należącymi do macierzy zewnątrzkomórkowej. Ekspresja ligandów w pojedynczych komórkach była zdefiniowana wartością logiczną zgodnie z zasadami logiki rozmytej. Wartość ta była uzyskiwana z ekspresji danego genu przekształconej funkcją logistyczną o parametrach dostosowanych do ekspresji tego genu.W połączonych danych podzielono komórki zgodnie z ustanowionymi typami śródbłonka, jak również zidentyfikowano nie opisaną jak dotąd frakcję. Analiza interakcji biorąca pod uwagę wszystkie rodzaje ligandów pozwoliła wskazać nie opisaną frakcję komórek jako komórki o wyjątkowo silnych interakcjach z komórkami HSC i MPP. Analiza biorąca pod uwagę jedynie ligandy błonowe wykazywała interakcje o porównywalnej sile dla komórek arteriolarnych i sinusoidalnych. Wyniki te nie pozwoliły rozstrzygnąć między niszą arteriolarną i sinusoidalną, sugerują jednak istnienie niszy opartej na nowej populacji komórek śródbłonka. Wskazują również na brak odrębnej niszy dla komórek HSC. Aby ułatwić identyfikację tej nowej populacji ECs w metodach cytometrycznych i mikroskopowych, użyto metod uczenia maszynowego do identyfikacji genów białek powierzchniowych umożliwiających najłatwiejsze rozróżnienie między tymi komórkami.Przeprowadzona analiza pozwoliła zidentyfikować nie opisaną jak dotąd populację ECs, która najprawdopodobniej stanowi część niszy hematopoetycznej. Zaproponowano również markery powierzchniowej pomocne w jej identyfikacji.In the body, all blood cells derive from a rare population of hematopoietic stem cells (HSCs). An important role in maintaining and regulating the activity of HSC is performed by the hematopoietic niche, a specialized, heterogeneous group of cells that create their microenvironment in the bone marrow. Despite extensive research and analysis, there is no agreement regarding the specific components and localization of the niche. Most contemporary works support existence of perivascular niche, however they disagree over the specific type of vessel in proximity of which it is supposed to be located. Therefore, the purpose of the work was to identify the subpopulation of endothelial cells (ECs) participating in the hematopoietic niche.We assumed that the ECs fraction building the hematopoietic niche maintains molecular interactions with hematopoietic stem cells (HSC) and multipotent progenitor cells (MPP) and that these interactions can be predicted based on single cells RNA sequencing. We used ECs data obtained by three independent research teams.Cells suspected of interacting with types of hematopoietic cells have been selected based on the number of individual molecular interactions between these cells. Information on molecular interactions was obtained from a curated database of interactions between membrane receptors and membrane, secretory and extracellular matrix (ECM) ligands. Expression of ligands in single cells was defined by fuzzy logic values. These values were obtained by transforming expression data using logistic function, with parameters specific for each gene.In the combined data, the cells were divided according to the established endothelial subpopulations and new, previously not defined subset has been found. Interactions analysis for all types of ligands, identified newly found subset, as cells with strongest interactions with HSC and MPP cells. Analysis based only on membrane ligands showed interactions of comparable strength for arteriolar and sinusoidal cells. The results cannot conclusively support either arteriolar or sinusoidal niche, suggesting existence of niche based on the new ECs subpopulation. There is also no proof for existence of separate niche for HSC. To facilitate the identification of this new ECs group using cytometry and microscopy, we defined set of surface markers, using machine learning, which enable easy identification of all defined ECs types.In conclusion, the performed analysis allowed to identify a previously not described population of ECs, which is probably part of the hematopoietic niche. Surface markers for identifying all ECs subpopulations have also been proposed

Politicians' blogs - popularity indicators

Blogi są zjawiskiem złożonym i różnorodnym. Można je podzielić według wielu różnych kryteriów. Jednym z rodzajów blogów są blogi polityków. Już od kilku lat politycy korzystają z możliwości oferowanych przez blogosferę. Blogosfera polskich polityków jest bardzo zróżnicowana i nieproporcjonalna. Istnieje kilka czynników - wewnętrznych i zewnętrznych - które wpływają na stopień popularności danego bloga. Czynniki te są od siebie dość niezależne.Blogs are a complex and diverse phenomenon. They can be grouped by many different indicators. One of the groups of blogs are politicians' blogs. For several years already, politicians have been taking benefits from blogosphere possibilities. Blogosphere of Polish politicians is really diverse and disproportionate. There are several indicators - both inner and outer - which are influencing on a popularity level of blogs. Those indicators are quite independent

Internet's public debate regarding controversial events

Wraz z rozwojem coraz to nowszych mediów związanych z internetem, stał się on istotną przestrzenią do prowadzenia debaty publicznej. Cyfryzacja mediów i społeczeństwa niesie ze sobą nie tylko nowe możliwości, ale i zagrożenia. Analizując współczesną debatę internetową na temat rozmaitych wydarzeń, które charakteryzuje wysoki stopień kontrowersyjności, zauważyć można specyficzne, powtarzające się w niej motywy przewodnie.With the constant development of newer and newer media, the internet became a substantial stage for public debate. The digitalization of media and society brings not only new opportunities, but also dangers. When analyzing modern internet's public debate, regarding various events, which are highly controversial, one can notice certain specific, recurring keynotes

Survival and Neurogenesis-Promoting Effects of the Co-Overexpression of BCLXL and BDNF Genes on Wharton’s Jelly-Derived Mesenchymal Stem Cells

The main problem with using MSC (mesenchymal stem cells) to treat the deficient diseases of the central nervous system is the low cell survival rate after the transplant procedure and their low ability to spontaneously differentiate into functional neurons. The aim of this study was to investigate the effects of genetically modifying MSC. A co-overexpression of two genes was performed: BCLXL was supposed to increase the resistance of the cells to the toxic agents and BDNF was supposed to direct cells into the neuronal differentiation pathway. As a result, it was possible to obtain the functional overexpression of the BCLXL and BDNF genes. These cells had an increased resistance to apoptosis-inducing toxicants (staurosporine, doxorubicin and H2O2). At the same time, the genes of the neuronal pathway (CHAT, TPH1) were overexpressed. The genetically modified MSC increased the survival rate under toxic conditions, which increased the chance of surviving a transplant procedure. The obtained cells can be treated as neural cell progenitors, which makes them a universal material that can be used in various disease models. The production of neurotransmitters suggests that cells transplanted into the brain and subjected to the additional influence of the brain’s microenvironment, will be able to form synapses and become functional neurons

Distinct glycosylation and functional profile of typhoid vaccine-induced antibodies in a UK challenge study and Nepalese children

Vaccines against typhoid fever have been shown to be safe and effective in field trials. The mechanism through which the vaccines protect remains elusive. Recent data have implicated antibody glycosylation, and specifically afucosylated antibodies, as an important factor in vaccine-induced effector function for a range of viral infections, however this has not been evaluated for vaccines against bacterial infections such as Salmonella typhi. Here, we studied antibody glycosylation after either Vi-conjugate or Vi-polysaccharide vaccine in a UK cohort who were then challenged with virulent S. typhi, and compared findings to antibody glycosylation after Vi-conjugate vaccine in Nepalese children living in a typhoid endemic region. We compared vaccine-induced responses and correlated these measures with antibody-dependent function. Robust antigen-specific antibody galactosylation and sialylation modifications were induced by both vaccines in UK adults, with Vi-conjugate vaccine inducing Vi-specific glycan changes of higher magnitude than Vi-polysaccharide. Among those individuals diagnosed with typhoid fever after challenge, a distinct glycan profile was correlated with disease severity. Elevated galactosylation and sialylation was correlated with increased antibody-dependent phagocytosis by macrophages and neutrophils among UK adults. While bulk IgG glycosylation differed between Nepalese children and UK adults, vaccination with the Vi-conjugate vaccine overcame these differences to result in similar Vi-specific antibody glycosylation profiles 28 days after vaccination in both cohorts

Working togs, Dai cap and Tommy box: a response to Evan Walter's 1936 portrait 'A Welsh Collier'

https://thekeep.eiu.edu/commencement_spring2018/1097/thumbnail.jp