147 research outputs found
Myosin II Activity Is Selectively Needed for Migration in Highly Confined Microenvironments in Mature Dendritic Cells
Upon infection, mature dendritic cells (mDCs) migrate from peripheral tissue to lymph nodes (LNs) to activate T lymphocytes and initiate the adaptive immune response. This fast and tightly regulated process is tuned by different microenvironmental factors, such as the physical properties of the tissue. Mechanistically, mDCs migration mostly relies on acto-myosin flow and contractility that depend on non-muscular Myosin IIA (MyoII) activity. However, the specific contribution of this molecular motor for mDCs navigation in complex microenvironments has yet to be fully established. Here, we identified a specific role of MyoII activity in the regulation of mDCs migration in highly confined microenvironments. Using microfluidic systems, we observed that during mDCs chemotaxis in 3D collagen gels under defined CCL21 gradients, MyoII activity was required to sustain their fast speed but not to orientate them toward the chemokine. Indeed, despite the fact that mDCs speed declined, these cells still migrated through the 3D gels, indicating that this molecular motor has a discrete function during their motility in this irregular microenvironment. Consistently, using microchannels of different sizes, we found that MyoII activity was essential to maintain fast cell speed specifically under strong confinement. Analysis of cell motility through micrometric holes further demonstrated that cell contractility facilitated mDCs passage only over very small gaps. Altogether, this work highlights that high contractility acts as an adaptation mechanism exhibited by mDCs to optimize their motility in restricted landscapes. Hence, MyoII activity ultimately facilitates their navigation in highly confined areas of structurally irregular tissues, contributing to the fine-tuning of their homing to LNs to initiate adaptive immune responses
Corología de tres táxones de interés en el macizo del Castro Valnera: Eriophorum vaginatum L., Gentiana acaulis L. y Gentiana boryi Boiss
Se ofrece una visión actualizada de la situación en el macizo del Castro
Valnera de tres especies de alto interés regional: Eriophorum vaginatum L., Gentiana
acaulis L. y Gentiana boryi Boiss. Se comentan datos sobre la historia de su descubrimiento
en ese macizo. Se recogen y enumeran para cada uno de ellos los datos de recolecciones,
citas bibliográficas y de campo. Con el conjunto de todas ellas se elaboran varios
mapas. Finalmente, se aportan comentarios que contribuyen al conocimiento de su
comportamiento ecológico y se apuntan algunas pautas y criterios a tener en cuenta para
su protección
Pre-pregnancy maternal obesity associates with endoplasmic reticulum stress in human umbilical vein endothelium
Obesity associates with the endoplasmic reticulum (ER) stress-induced endothelial dysfunction. Pregnant women with pre-pregnancy maternal obesity (PGMO) may transfer this potential risk to their offspring; however, whether ER stress occurs and associates with foetoplacental endothelial dysfunction in PGMO is unknown. We studied the l-arginine transport and nitric oxide (NO) synthesis in human umbilical vein endothelial cells (HUVECs) from women with PGMO or with a normal pre-pregnancy weight. We analysed the expression and activation of the ER stress sensors protein kinase RNA-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1α (IRE1α), and activating transcription factor 6 (ATF6). PGMO associated with lower endothelial NO synthase activity due to increased Thr-inhibitor and decreased Ser-stimulator phosphorylation. However, higher expression and activity of the human cationic amino acid transporter 1 was found. PGMO caused activation of PERK and its downstream targets eukaryotic initiation factor 2 (eIF2α), C/EBP homologous protein 10 (CHOP), and tribbles-like protein 3 (TRB3). Increased IRE1α protein abundance (but not its phosphorylation or X-box binding protein 1-mRNA splicing) and increased c-Jun N-terminal kinase 1 phosphorylation was seen in PGMO. A preferential nuclear location of the activating transcription factor 6 (ATF6) was found in HUVECs from PGMO. All the changes seen in PGMO were blocked by TUDCA but unaltered by tunicamycin. Thus, PGMO may determine a state of ER stress via upregulation of the PERK-eIF2α-CHOP-TRB3 axis signalling in HUVECs. This phenomenon results in foetoplacental vascular endothelial dysfunction at birth
Adiciones y revisiones al Atlas de la flora vascular silvestre de Burgos, VII
Se mencionan 73 táxones con citas y/o comentarios referidos a su existencia
en la provincia de Burgos. De ellos 13 suponen una novedad para el catálogo provincial
Recommended from our members
Size control in mammalian cells involves modulation of both growth rate and cell cycle duration
Despite decades of research, how mammalian cell size is controlled remains unclear because of the difficulty of directly measuring growth at the single-cell level. Here we report direct measurements of single-cell volumes over entire cell cycles on various mammalian cell lines and primary human cells. We find that, in a majority of cell types, the volume added across the cell cycle shows little or no correlation to cell birth size, a homeostatic behavior called “adder”. This behavior involves modulation of G1 or S-G2 duration and modulation of growth rate. The precise combination of these mechanisms depends on the cell type and the growth condition. We have developed a mathematical framework to compare size homeostasis in datasets ranging from bacteria to mammalian cells. This reveals that a near-adder behavior is the most common type of size control and highlights the importance of growth rate modulation to size control in mammalian cells
Methylation alterations are not a major cause of PTTG1 missregulation
Background: On its physiological cellular context, PTTG1 controls sister chromatid segregation
during mitosis. Within its crosstalk to the cellular arrest machinery, relies a checkpoint of integrity
for which gained the over name of securin. PTTG1 was found to promote malignant transformation
in 3T3 fibroblasts, and further found to be overexpressed in different tumor types. More recently,
PTTG1 has been also related to different processes such as DNA repair and found to trans-activate
different cellular pathways involving c-myc, bax or p53, among others. PTTG1 over-expression has
been correlated to a worse prognosis in thyroid, lung, colorectal cancer patients, and it can not be
excluded that this effect may also occur in other tumor types. Despite the clinical relevance and
the increasing molecular characterization of PTTG1, the reason for its up-regulation remains
unclear.
Method: We analysed PTTG1 differential expression in PC-3, DU-145 and LNCaP tumor cell
lines, cultured in the presence of the methyl-transferase inhibitor 5-Aza-2'-deoxycytidine. We also
tested whether the CpG island mapping PTTG1 proximal promoter evidenced a differential
methylation pattern in differentiated thyroid cancer biopsies concordant to their PTTG1
immunohistochemistry status. Finally, we performed whole-genome LOH studies using Affymetix
50 K microarray technology and FRET analysis to search for allelic imbalances comprising the
PTTG1 locus.
Conclusion: Our data suggest that neither methylation alterations nor LOH are involved in
PTTG1 over-expression. These data, together with those previously reported, point towards a
post-transcriptional level of missregulation associated to PTTG1 over-expression.This project was funded by The Fundación de Investigación Biomédica Mutua Madrileña Automovilista. Neocodex have been partially funded by the Ministerio de Educación y Ciencia of Spain (FIT-010000-2004-69, PTQ04-1-0006, PTQ2003-0549, PTQ2003-0546 and PTQ2003-0783). MAJ was also supported by SAF2005- 07713-C03-03 and CS by FIS 06/757
Adiciones y revisiones al Atlas de flora vascular silvestre de Burgos, X
Se mencionan 61 táxones con citas y/o comentarios referidos a su existencia en la provincia de Burgos. De ellos, 3 suponen una novedad para el catálogo provincial61 taxa with either quotations or remarks, related to their existence within the province of Burgos, are mentioned. 3 out of these aforementioned ones mean a valuable novelty for the provincial catalogue
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