Analyzing the behavior of normoxic and hypoxic cells through the use of microfluidic devices

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
K. Chen ◽  
Rexius M. ◽  
D.T. Eddington
Keyword(s):  
Vascular Endothelial Cells ◽  
Experimental Testing ◽  
Hypoxia Inducible Factor ◽  
Human Mesenchymal Stem Cells ◽  
Microfluidic Devices ◽  
The Body ◽  
Cellular Growth ◽  
Hypoxic Conditions ◽  
Cellular Analysis ◽  
Growth Factor Production

Current cellular exposure to atmospheric normoxic (21%) oxygen concentrations have been proven to be physiologically inaccurate since the human body only ranges between 1%-13% in the body. We wish to observe how human mesenchymal stem cells (hMSCs) and human lung micro vascular endothelial cells (HLMVECs) interact with one another and their behavior when exposed to either hypoxic (defined as being less than normoxic) or atmospheric normoxic concentrations. The cells were grown and cultured on microfluidic devices - a relatively cheap and easily fabricated method of experimental testing that can lend itself to mass production and cellular analysis techniques. The analyses mainly focus on quantifying the amount of hypoxia-inducible factor-1 (HIF-1) present in the cells - this factor is responsible for activating countless transcription factors within the cell. Overall, these methods and tests have provided evidence to the fact that hypoxic conditions increase cellular growth, migration, proliferation, and growth factor production by almost two times.

Hypoxia inhibits senescence and maintains mesenchymal stem cell properties through down-regulation of E2A-p21 by HIF-TWIST

Blood ◽  
2011 ◽  
Vol 117 (2) ◽  
pp. 459-469 ◽  
Author(s):  
Chih-Chien Tsai ◽  
Yann-Jang Chen ◽  
Tu-Lai Yew ◽  
Ling-Lan Chen ◽  
Jir-You Wang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hypoxia Inducible Factor ◽  
Human Mesenchymal Stem Cells ◽  
Telomerase Activity ◽  
Rapid Expansion ◽  
Low Density ◽  
Down Regulation ◽  
Differentiation Potential ◽  
Hypoxic Conditions ◽  
Population Doublings

Abstract Although low-density culture provides an efficient method for rapid expansion of human mesenchymal stem cells (MSCs), MSCs enriched by this method undergo senescence and lose their stem cell properties, which could be preserved by combining low-density and hypoxic culture. The mechanism was mediated through direct down-regulation of E2A-p21 by the hypoxia-inducible factor–1α (HIF-1α)–TWIST axis. Expansion under normoxia induced E2A and p21 expression, which were abrogated by overexpression of TWIST, whereas siRNA against TWIST up-regulated E2A and p21 in hypoxic cells. Furthermore, siRNA against p21 in normoxic cells enhanced proliferation and increased differentiation potential, whereas overexpression of p21 in hypoxic cells induced a decrease in proliferation and a loss of differentiation capacity. More importantly, MSCs expanded under hypoxic conditions by up to 100 population doublings, exhibited telomerase activity with maintained telomere length, normal karyotyping, and intact genetic integrity, and did not form tumors. These results support low-density hypoxic culture as a method for efficiently expanding MSCs without losing stem cell properties or increasing tumorigenicity.

An Ultrastructural Study of Pericytes

1968 ◽  
Vol 26 ◽  
pp. 66-67
Author(s):  
T. M. Murad ◽  
E. von Haam
Keyword(s):  
Plasma Membrane ◽  
Endothelial Cell ◽  
Basement Membrane ◽  
Blood Vessel ◽  
Vascular Endothelial Cells ◽  
Myoepithelial Cells ◽  
Capillary Blood ◽  
The Body ◽  
Capillary Blood Vessel ◽  
Outer Plasma Membrane

Pericytes are vascular satellites present around capillary blood vessels and small venules. They have been observed in almost every tissue of the body and are thought to be related to vascular smooth muscle cells. Morphologically pericytes have great similarity to vascular endothelial cells and also slightly resemble myoepithelial cells.The present study describes the ultrastructural morphology of pericytes in normal breast tissue and in benign tumor of the breast. The study showed that pericytes are ovoid or elongated cells separated from the endothelial cell of the capillary blood vessel by the basement membrane of endothelial cell. The nuclei of pericytes are often very distinctive. Although some are round, oval, or elongated, others show marked irregularity and infolding of the nuclear membrane. The cytoplasm shows mono-or bipolar extension in which the cytoplasmic organelles are located (Fig. 1). These cytoplasmic extensions embrace the capillary blood vessel incompletely. The plasma membrane exhibits multiple areas of focal condensation called hemidesmosomes (Fig. 2, arrow). A variable number of pinocytotic vesicles are frequently seen lining the outer plasma membrane. Normally pericytes are surrounded by a basement membrane which is found more consistently on the outer plasma membrane separating the pericytes from the stromal connective tissue.

Chronic Hypoxia as a Potential Factor in Human Life-threatening Diseases

2017 ◽  
Vol 10 (4) ◽  
pp. 3759-3762
Author(s):  
Sandhya MNVS ◽  
Vanitha K ◽  
Ramesh A
Keyword(s):  
Chronic Hypoxia ◽  
Atmospheric Oxygen ◽  
Human Life ◽  
The Body ◽  
Cellular Damage ◽  
Otto Warburg ◽  
Regular Treatment ◽  
Breathing Exercises ◽  
Hypoxic Conditions ◽  
Cancerous Cell

The review article focuses on the importance of adequate oxygen levels in the body as cure and therapy for many ailments. It is known that hypoxia is the cause for cellular damage and if it can be applied to major patho-physiology’s, it can be observed that slow and chronic hypoxic conditions are the cause for most of the diseases. On the contrary, providing each cell of the body with proper oxygen may be helpful in maintaining the immunity of the body and therefore treating many disease conditions. This theory, if tested may show positive results in heart related diseases, neuronal disorders, stresses, digestive disorders and the unresolved cancer too. Slow decrease in the levels of atmospheric oxygen could be a reason to induce chronic hypoxia. According to Dr. Otto Warburg, a Noble laurate, a normal cell when deprived of oxygen, may get converted to a cancerous cell, whereas a cancerous cell cannot survive in aerobic conditions. If this part of his research be concentrated on, there could be fruitful results in the treatment of cancer. To maintain adequate levels of oxygen in the body, simple yogic breathing practices are helpful. And to maintain the adequate atmospheric oxygen, trees and plants which cleanse the atmospheric air are useful. Clinical surveys on volunteers who have been practicing regular breathing exercises can prove the fact that proper and concentrated respiration could prevent many diseases. Thus, supplementing breathing exercises along with the regular treatment for cancer patients could be helpful in alleviating cancer and other diseases.

scholarly journals Let-7f miRNA regulates SDF-1α- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Virginia Egea ◽  
Kai Kessenbrock ◽  
Devon Lawson ◽  
Alexander Bartelt ◽  
Christian Weber ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tumor Growth ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Human Mesenchymal Stem Cells ◽  
Target Cells ◽  
Autophagic Flux ◽  
Stromal Cell Derived Factor

AbstractBone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.

scholarly journals Analyses of the pericyte transcriptome in ischemic skeletal muscles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuan-chi Teng ◽  
Alfredo Leonardo Porfírio-Sousa ◽  
Giulia Magri Ribeiro ◽  
Marcela Corso Arend ◽  
Lindolfo da Silva Meirelles ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Limb Ischemia ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Arterial Disease ◽  
The Body ◽  
Time Points

Abstract Background Peripheral arterial disease (PAD) affects millions of people and compromises quality of life. Critical limb ischemia (CLI), which is the most advanced stage of PAD, can cause nonhealing ulcers and strong chronic pain, and it shortens the patients’ life expectancy. Cell-based angiogenic therapies are becoming a real therapeutic approach to treat CLI. Pericytes are cells that surround vascular endothelial cells to reinforce vessel integrity and regulate local blood pressure and metabolism. In the past decade, researchers also found that pericytes may function as stem or progenitor cells in the body, showing the potential to differentiate into several cell types. We investigated the gene expression profiles of pericytes during the early stages of limb ischemia, as well as the alterations in pericyte subpopulations to better understand the behavior of pericytes under ischemic conditions. Methods In this study, we used a hindlimb ischemia model to mimic CLI in C57/BL6 mice and explore the role of pericytes in regeneration. To this end, muscle pericytes were isolated at different time points after the induction of ischemia. The phenotypes and transcriptomic profiles of the pericytes isolated at these discrete time points were assessed using flow cytometry and RNA sequencing. Results Ischemia triggered proliferation and migration and upregulated the expression of myogenesis-related transcripts in pericytes. Furthermore, the transcriptomic analysis also revealed that pericytes induce or upregulate the expression of a number of cytokines with effects on endothelial cells, leukocyte chemoattraction, or the activation of inflammatory cells. Conclusions Our findings provide a database that will improve our understanding of skeletal muscle pericyte biology under ischemic conditions, which may be useful for the development of novel pericyte-based cell and gene therapies.

Biomechanical interactions of Schistosoma mansoni eggs with vascular endothelial cells facilitate egg extravasation

2021 ◽  
Author(s):  
Yi-Ting Yeh ◽  
Danielle E. Skinner ◽  
Ernesto Criado-Hidalgo ◽  
Natalie Shee Chen ◽  
Antoni Garcia-De Herreros ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Schistosoma Mansoni ◽  
Disease Transmission ◽  
Vascular Endothelial Cells ◽  
Flexible Substrate ◽  
Blood Stream ◽  
The Body ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Maturation State

AbstractThe eggs of the parasitic blood fluke, Schistosoma, are the main drivers of the chronic pathologies associated with schistosomiasis, a disease of poverty afflicting approximately 220 million people worldwide. Eggs laid by Schistosoma mansoni in the bloodstream of the host are encapsulated by vascular endothelial cells (VECs), the first step in the migration of the egg from the blood stream into the lumen of the gut and eventual exit from the body. The biomechanics associated with encapsulation and extravasation of the egg are poorly understood. We demonstrate that S. mansoni eggs induce VECs to form two types of membrane extensions during encapsulation; filopodia that probe eggshell surfaces and intercellular nanotubes that presumably facilitate VEC communication. Encapsulation efficiency, the number of filopodia and intercellular nanotubes, and the length of these structures depend on the egg’s vitality and, to a lesser degree, its maturation state. During encapsulation, live eggs induce VEC contractility and membranous structures formation, in a Rho/ROCK pathway-dependent manner. Using elastic hydrogels embedded with fluorescent microbeads as substrates to culture VECs, live eggs induce VECs to exert significantly greater contractile forces during encapsulation than dead eggs, which leads to 3D deformations on both the VEC monolayer and the flexible substrate underneath. These significant mechanical deformations cause the VEC monolayer tension to fluctuate with eventual rupture of VEC junctions, thus facilitating egg transit out of the blood vessel. Overall, our data on the mechanical interplay between host VECs and the schistosome egg improve our understanding of how this parasite manipulates its immediate environment to maintain disease transmission.

Analysis of hypoxia-associated dendritic cells in colitic mice and effects of probiotics on IL-10 production in inflammatory dendritic-cells under hypoxia

2019 ◽  
Vol 10 (7) ◽  
pp. 801-810
Author(s):  
T. Ogita ◽  
J. Miyamoto ◽  
Y. Hirabayashi ◽  
M. Rossi ◽  
G. Mazzarella ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
Hypoxia Inducible Factor ◽  
Flow Cytometric Analysis ◽  
Bifidobacterium Bifidum ◽  
Sodium Sulphate ◽  
Mesenteric Lymph Nodes ◽  
Cellular Mechanisms ◽  
Hypoxic Conditions ◽  
Anti Inflammatory

The aim of this study was to analyse hypoxia-associated dendritic cells (DCs) in colitic mice and the effects of probiotics on interleukin (IL)-10 production in inflammatory DCs under hypoxic conditions. Extensive hypoxia was observed in the colonic mucosa of dextran sodium sulphate-induced colitic mice. Flow cytometric analysis demonstrated that hypoxia-inducible factor-1α+ DCs in colonic lamina propria (CLP) lymphocytes and mesenteric lymph nodes (MLN) were more abundant in colitic mice than those in controls. Among three subsets of DCs, i.e. plasmacytoid DCs, conventional DCs (cDCs), and monocyte-derived DCs (mDCs), cDCs and mDCs were more abundant in CLP of colitic mice. Bone marrow-derived Flt-3L-induced DCs (Flt-DCs) but not bone marrow-derived GM-CSF-induced DCs (GM-DCs), incubated with 1% O2 exhibited an inflammatory phenotype, with higher CD86, IL-6, and tumour necrosis factor-α expression, and lower IL-10 levels than those in Flt-DCs incubated with 21% O2. The hypoxia-induced decrease in IL-10 expression in Flt-DCs was restored by Bifidobacterium bifidum JCM 1255T promoted IL-10 expression through the p38 pathway under normoxic conditions. The anti-inflammatory effects of B. bifidum JCM 1255T in Flt-DCs were mediated through different cellular mechanisms under hypoxic and normoxic conditions. B. bifidum JCM 1255T could be used therapeutically for its anti-inflammatory effects.

scholarly journals Total flavonoids from Astragalus alleviate endothelial dysfunction by activating the Akt/eNOS pathway

2017 ◽  
Vol 46 (6) ◽  
pp. 2096-2103 ◽  
Author(s):  
Qian Liu ◽  
Ling Zhang ◽  
Qiyuan Shan ◽  
Yuxia Ding ◽  
Zhaocai Zhang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Vascular Endothelial Cells ◽  
Ex Vivo ◽  
Umbilical Vein ◽  
Cell Counting ◽  
Total Flavonoids ◽  
Vascular Endothelial ◽  
Protective Effects ◽  
Hypoxic Conditions ◽  
Underlying Mechanisms

Objective To investigate the vasodilative and endothelial-protective effects and the underlying mechanisms of total flavonoids from Astragalus (TFA). Methods The vasodilative activities of TFA were measured with a myograph ex vivo using rat superior mesenteric arterial rings. The primary human umbilical vein endothelial cell (HUVEC) viabilities were assayed using the cell counting kit-8 after hypoxia or normoxia treatment with or without TFA. Akt, P-Akt, eNOS, P-eNOS, Erk, P-Erk, Bcl-2 and Bax expression were analyzed using western blotting. Results TFA showed concentration-dependent vasodilative effects on rat superior mesenteric arterial rings, but had no effects on normal or potassium chloride precontracted arterial rings. TFA did not affect HUVEC viabilities in normoxia, but dramatically promoted cell proliferation in the concentration range of 1 to 30 µg/mL under hypoxia. Moreover, TFA significantly increased the ratios of P-Akt/Akt and P-eNOS/eNOS in vascular endothelial cells under hypoxic conditions, but did not change the P-Erk/Erk or Bcl-2/Bax ratios. Conclusions TFA might exhibit vasorelaxant and endothelial-protective effects via the Akt/eNOS signaling pathway.

scholarly journals Hypoxia increases KIAA1199/CEMIP expression and enhances cell migration in pancreatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takuya Oba ◽  
Norihiro Sato ◽  
Yasuhiro Adachi ◽  
Takao Amaike ◽  
Yuzan Kudo ◽  
...  
Keyword(s):  
Cell Migration ◽  
Protein Expression ◽  
Hypoxia Inducible Factor ◽  
Ductal Adenocarcinoma ◽  
Rt Pcr ◽  
Transwell Migration Assay ◽  
Migration Assay ◽  
Hypoxic Conditions ◽  
Mrna And Protein Expression ◽  
Interfering Rna

AbstractPancreatic ductal adenocarcinoma (PDAC) is characterised by dense desmoplasia and hypoxic microenvironment. Our previous reports demonstrated that hyaluronan (HA), especially low-molecular-weight HA, provides a favourable microenvironment for PDAC progression. However, the effect of hypoxia on HA metabolism remains unknown. Using quantitative real-time RT-PCR and western blot analysis, we analysed the changes in the expression of HA-synthesizing enzymes (HAS2 and HAS3) and HA-degrading enzymes (HYAL1, KIAA1199/CEMIP) in PDAC cell lines under hypoxic conditions. Hypoxia increased the mRNA and protein expression of KIAA1199, whereas it decreased HYAL1 expression. The expression of HAS3 was increased and HAS2 remained unchanged in response to hypoxia. The effect of KIAA1199 on hypoxia-induced cell migration was determined using a transwell migration assay and small-interfering RNA (siRNA). Hypoxia enhanced the migratory ability of PDAC cells, which was inhibited by KIAA1199 knockdown. We also used immunohistochemistry to analyse the protein expression of hypoxia inducible factor (HIF) 1α and KIAA1199 in PDAC tissues. There was a significant immunohistochemically positive correlation between KIAA1199 and HIF1α. These findings suggest that hypoxia-induced KIAA1199 expression may contribute to enhanced motility in PDAC.

Sign in / Sign up

Export Citation Format

Share Document