Relatively quiescent tissues like salivary glands (SGs) respond to stimuli such as injury to expand, replace and regenerate. Resident stem/progenitor cells are key in this process because, upon ...activation, they possess the ability to self-renew. Macroautophagy/autophagy contributes to and regulates differentiation in adult tissues, but an important question is whether this pathway promotes stem cell self-renewal in tissues. We took advantage of a 3D organoid system that allows assessing the self-renewal of mouse SGs stem cells (SGSCs). We found that autophagy in dormant SGSCs has slower flux than self-renewing SGSCs. Importantly, autophagy enhancement upon SGSCs activation is a self-renewal feature in 3D organoid cultures and SGs regenerating in vivo. Accordingly, autophagy ablation in SGSCs inhibits self-renewal whereas pharmacological stimulation promotes self-renewal of mouse and human SGSCs. Thus, autophagy is a key pathway for self-renewal activation in low proliferative adult tissues, and its pharmacological manipulation has the potential to promote tissue regeneration.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Salivary glands are damaged by radiotherapy for head and neck cancers, which often culminates in radiation-induced hyposalivation and xerostomia that may be permanent. Here, we identified a central ...role for YAP in the regenerative response of the salivary gland. Activation of the Hippo signaling pathway inhibits the phosphorylation of YAP, leading to its nuclear translocation and transcriptional activity. Using mice with salivary gland injury induced by surgical ligation and salivary gland–derived organoids, we found that YAP nuclear localization in the salivary gland epithelium changed dynamically between homeostasis and regeneration. Whereas local injury had no effect on nuclear YAP localization in saliva-producing acinar cells, it triggered nuclear accumulation of YAP in saliva-transporting ductal cells. Injury also stimulated the proliferation of ductal cells, which were mainly quiescent under homeostatic conditions and in nonregenerating areas distal to the injury site, thus enabling salivary gland regeneration. Overexpressing YAP or driving YAP nuclear translocation by inhibiting upstream Hippo pathway kinases increased the capacity of mouse and human salivary gland cells, including human cells that had been irradiated, to form lobed organoids in vitro. Our results identify a YAP-driven regeneration program in salivary gland ductal cells that could be used to promote salivary gland regeneration after irradiation-induced damage.
Radiotherapy is involved in the treatment of many cancers, but damage induced to the surrounding normal tissue is often inevitable. Evidence suggests that the maintenance of homeostasis and ...regeneration of the normal tissue is driven by specific adult tissue stem/progenitor cells. These tasks involve the input from several signaling pathways. Irradiation also targets these stem/progenitor cells, triggering a cellular response aimed at achieving tissue regeneration. Here we discuss the currently used in vitro and in vivo models and the involved specific tissue stem/progenitor cell signaling pathways to study the response to irradiation. The combination of the use of complex in vitro models that offer high in vivo resemblance and lineage tracing models, which address organ complexity constitute potential tools for the study of the stem/progenitor cellular response post-irradiation. The Notch, Wnt, Hippo, Hedgehog, and autophagy signaling pathways have been found as crucial for driving stem/progenitor radiation-induced tissue regeneration. We review how these signaling pathways drive the response of solid tissue-specific stem/progenitor cells to radiotherapy and the used models to address this.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Vascular endothelial growth factor (VEGF)-A induces endothelial hyperpermeability, but the molecular pathways remain incompletely understood. Endothelial nitric oxide synthase (eNOS) regulates acute ...effects of VEGF-A on permeability of endothelial cells (ECs), but it remains unknown whether and how eNOS regulates late effects of VEGF-A-induced hyperpermeability. Here we show that VEGF-A induces hyperpermeability via eNOS-dependent and eNOS-independent mechanisms at 2 days after VEGF-A stimulation. Silencing of expression of the eNOS gene (NOS3) reduced VEGF-A-induced permeability for dextran (70 kDa) and 766 Da-tracer in human dermal microvascular ECs (HDMVECs), but not in human retinal microvascular ECs (HRECs) and human umbilical vein ECs (HUVECs). However, silencing of NOS3 expression in HRECs increased permeability to dextran, BSA and 766 Da-tracer in the absence of VEGF-A stimulation, suggesting a barrier-protective function of eNOS. We also investigated how silencing of NOS3 expression regulates the expression of permeability-related transcripts, and found that NOS3 silencing downregulates the expression of PLVAP, a molecule associated with trans-endothelial transport via caveolae, in HDMVECs and HUVECs, but not in HRECs. Our findings underscore the complexity of VEGF-A-induced permeability pathways in ECs and the role of eNOS therein, and demonstrate that different pathways are activated depending on the EC phenotype.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Lactate and ATP formation by aerobic glycolysis, the Warburg effect, is considered a hallmark of cancer. During angiogenesis in non-cancerous tissue, proliferating stalk endothelial cells (ECs) also ...produce lactate and ATP by aerobic glycolysis. In fact, all proliferating cells, both non-cancer and cancer cells, need lactate for the biosynthesis of building blocks for cell growth and tissue expansion. Moreover, both non-proliferating cancer stem cells in tumors and leader tip ECs during angiogenesis rely on glycolysis for pyruvate production, which is used for ATP synthesis in mitochondria through oxidative phosphorylation (OXPHOS). Therefore, aerobic glycolysis is not a specific hallmark of cancer but rather a hallmark of proliferating cells and limits its utility in cancer therapy. However, local treatment of angiogenic eye conditions with inhibitors of glycolysis may be a safe therapeutic option that warrants experimental investigation. Most types of cells in the eye such as photoreceptors and pericytes use OXPHOS for ATP production, whereas proliferating angiogenic stalk ECs rely on glycolysis for lactate and ATP production. (J Histochem Cytochem XX.XXX–XXX, XXXX)
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Objective
Hyposalivation‐related xerostomia is an irreversible, untreatable, and frequent condition after radiotherapy for head and neck cancer. Stem cell therapy is an attractive option of ...treatment, but demands knowledge of stem cell functioning. Therefore, we aimed to develop a murine parotid gland organoid model to explore radiation response of stem cells in vitro.
Materials and Methods
Single cells derived from murine parotid gland organoids were passaged in Matrigel with defined medium to assess self‐renewal and differentiation potential. Single cells were irradiated and plated in a 3D clonogenic stem cell survival assay to assess submandibular and parotid gland radiation response.
Results
Single cells derived from parotid gland organoids were able to extensively self‐renew and differentiate into all major tissue cell types, indicating the presence of potential stem cells. FACS selection for known salivary gland stem cell markers CD24/CD29 did not further enrich for stem cells. The parotid gland organoid‐derived stem cells displayed radiation dose–response curves similar to the submandibular gland.
Conclusions
Murine parotid gland organoids harbor stem cells with long‐term expansion and differentiation potential. This model is useful for mechanistic studies of stem cell radiation response and suggests similar radiosensitivity for the parotid and submandibular gland organoids.
Full text
Available for:
CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Stem/progenitor cells are required for maintenance of salivary gland (SG) function and serve as untapped reservoirs to create functional cells. Despite recent advancements in the identification of ...stem/progenitor pools, in the submandibular gland (SMG), a knowledge gap remains. Furthermore, the contribution to adult SMG homeostasis of stem/progenitor cells originating from embryonic development is unclear. Here, we employ an H2B-GFP embryonic and adult pulse-and-chase system to characterize potential SMG stem/progenitor cells (SGSCs) based on quiescence at different stages. Phenotypical profiling of quiescent cells in the SMG revealed that label-retaining cells (LRCs) of embryonic or adult origin co-localized with CK8+ ductal or vimentin + mesenchymal, but not with CK5+ or CK14 + stem/progenitor cells. These SMG LRCs failed to self-renew in vitro while non-label retaining cells displayed differentiation and long-term expansion potential as organoids. Collectively, our data suggest that an active cycling population of cells is responsible for SMG homeostasis with organoid forming potential.
Display omitted
•Embryonic quiescent cells do not retain stemness in the adult submandibular gland (SMG)•Postnatal quiescent cells do not exhibit stem/progenitor cell potency in the adult SMG•Quiescent cells do not contribute to the homeostatic maintenance of the murine SMG•Adult murine SMG stem/progenitor cells are likely to be an actively cycling population
Biological sciences; Cell biology; Stem cells research;
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
MYC alterations influence the survival of patients with diffuse large B-cell lymphoma. Most studies have focused on MYC translocations but there is little information regarding the impact of ...numerical alterations and protein expression. We analyzed the genetic alterations and protein expression of MYC, BCL2, BCL6, and MALT1 in 219 cases of diffuse large B-cell lymphoma. MYC rearrangement occurred as the sole abnormality (MYC single-hit) in 3% of cases, MYC and concurrent BCL2 and/or BCL6 rearrangements (MYC double/triple-hit) in 4%, MYC amplifications in 2% and MYC gains in 19%. MYC single-hit, MYC double/triple-hit and MYC amplifications, but not MYC gains or other gene rearrangements, were associated with unfavorable progression-free survival and overall survival. MYC protein expression, evaluated using computerized image analysis, captured the unfavorable prognosis of MYC translocations/amplifications and identified an additional subset of patients without gene alterations but with similar poor prognosis. Patients with tumors expressing both MYC/BCL2 had the worst prognosis, whereas those with double-negative tumors had the best outcome. High MYC expression was associated with shorter overall survival irrespectively of the International Prognostic Index and BCL2 expression. In conclusion, MYC protein expression identifies a subset of diffuse large B-cell lymphoma with very poor prognosis independently of gene alterations and other prognostic parameters.
El ausentismo laboral es un fenómeno frecuente en las empresas, que se deriva de diversas causas y que genera un impacto negativo en el área económica y en el desarrollo de las actividades normales ...de los trabajadores, lo que da como resultado aumento en los costos y sobrecarga laboral para los demás empleados. Objetivo: establecer cuáles son las motivaciones de los profesionales de la salud en el Hospital Vista Hermosa nivel I, entidad de salud del Estado para ausentarse de sus turnos programados. Materiales y métodos: este estudio pretende un alcance técnico, requiere del análisis cualitativo y cuantitativo de las variables que intervienen en la satisfacción laboral de los empleados del centro de atención médica inmediata (CAMI) Vista Hermosa. Resultados: existe un alto índice de permanencia del vínculo profesional con la empresa, que se representa en un 42 % de tiempo trabajado entre dos años y diez años, seguido de un 33 % de tiempo trabajado por más de diez años, lo que refleja estabilidad laboral y el interés de la entidad por mantener al personal de salud. Se encontró un alto grado de satisfacción, con un 42 %, seguido de un 25 % de empleados muy satisfechos. Este hallazgo se relaciona con las motivaciones y garantías que presta el hospital a sus empleados, representadas en el salario, facilidades para cambios de turno y bonificaciones anuales, entre otras. Conclusiones: en este estudio se conoció que las principales causas de ausentismo en el CAMI Vista Hermosa fueron incapacidad por enfermedad, retraso o ausencia por trabajo adicional y calamidad doméstica, lo que se asocia directamente con el hecho de que la empresa pertenece al sector salud, donde existe una carga laboral alta y una cultura de tener uno o más trabajos simultáneamente.
NOTCH signaling suppresses tumor growth and proliferation in several types of stratified epithelia. Here, we show that missense mutations in NOTCH1 and NOTCH2 found in human bladder cancers result in ...loss of function. In murine models, genetic ablation of the NOTCH pathway accelerated bladder tumorigenesis and promoted the formation of squamous cell carcinomas, with areas of mesenchymal features. Using bladder cancer cells, we determined that the NOTCH pathway stabilizes the epithelial phenotype through its effector HES1 and, consequently, loss of NOTCH activity favors the process of epithelial-mesenchymal transition. Evaluation of human bladder cancer samples revealed that tumors with low levels of HES1 present mesenchymal features and are more aggressive. Together, our results indicate that NOTCH serves as a tumor suppressor in the bladder and that loss of this pathway promotes mesenchymal and invasive features.
PDF
