Search Results for: hypoxia

Physioxia or Hypoxia: what it’s all about

Cell culture under oxygen controlled conditions: an improvement towards more predictive results

Oxygen concentration in tissues is a key factor for cell and organ survival. In normal conditions, partial oxygen pressure (pO2) results in the balance between oxygen delivery and its consumption. Oxygen is transported, in mammals, by circulating red blood cells. Partial oxygen pressure in tissues varies widely, depending on their respective metabolic requirements and their functional status. In normal physiological conditions,  partial oxygen pressure is called physioxia. Any alteration of tissue environment leading to a decrease in partial oxygen pressure is called hypoxia. Hypoxic conditions have been observed in many different pathological situations like tumor development, obesity or transcient ischemia. [Read more…]

Focus on the Hypoxia Regulation Mechanism

The cellular and physiological effects resulting from hypoxia-dependent networks have been clearly shown to impact a number of human pathological states, including ischemic disease, diabetes, pulmonary disease and, perhaps most notably, cancer. Thus, further research into the biomedical effects of hypoxia could lead to novel therapeutic approaches for these diseases.

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Focus on the Hypoxia Pathway…

Hypoxia in tumors is closely associated with tumor aggressiveness and resistance to radio- and chemotherapeutic treatment. Therefore, reliable markers for hypoxia represent both valuable diagnostic markers and potential targets for investigation.

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2 cost-effective antibody options for Hypoxia pathway analysis

Low oxygen tension, or Hypoxia, regulates numerous cellular and tissular functions. In cancer research, hypoxia is a key regulator of tumor development, aggressiveness and therapy resistance by acting on malignant cells and their microenvironment. Hypoxia is also involved in age-related diseases and acts through intracellular and intercellular cascade of events (exosomes, paracrine loops, angiogenesis…) (1-2). [Read more…]

Oxygen and miRNAs in Cosmetology and Dermatology

A recent review by Nadim et al. casts some light on a Cosmetology and Dermatology, where circulating biomarkers, though studied to a certain extent so far, are yet unknown for many skin models. (1) A first element to have in mind when considering the skin-related experimental model is the “Oxygen level”. Oxygen levels may contribute to different findings, and the in vitro models used so far may not be so physiologically relevant as initially thought.

Hypoxia and miRNAs

Tissue oxygenation (which is a major part of the cell microenvironment) regulates the expression of the microRNAs called oxymiRs. OxymiRs may be categorized into three groups:

  1. microRNAs whose expression is directly modied by the Oxygen partial pressure,
  2. microRNAs whose expression is indirectly (pH, metabolites, etc.) modified by the Oxygen partial pressure, andpO2 percentage levels in various tissues
  3. microRNAs that target mediators of Oxygen sensing pathways to regulate biological networks for cell survival.

Examples of miRNAs important in skin physiology include miR-17, miR-21, miR-24, miR-27, miR-29b, miR-99 family, miR-125, miR-146a, miR-155, miR-203 and miR-205, among many other.

For example, in injured tissue, disruption of the vascular supply is associated with a low oxygen partial pressure, or hypoxia, which induces the expression of specic microRNAs referred to as HypoxamiRs (included in group (1) of the oxymiRs classification).

miR-210, known as the master HypoxamiR, is robustly induced under hypoxic conditions in nearly all kinds of cells. Under hypoxia, miR-21 also induces angiogenesis by targeting PTEN, leading to activation of AKT and ERK1/2 signaling pathways.

Transfection Factors and microRNAs

Other transcription factors such as p53 and NF-kB have been shown to affect the expression of microRNAs under hypoxia/anoxia conditions.

Numerous studies have demonstrated the modulation of microRNA expression and particularly that of the miR-200 family with oxidative stress due to excessive ROS levels.

Up to now, very few studies have shown the role of the intermediate Oxygen level (physioxia) in regulating microRNA expression in skin cells. Taken together, these results strongly support the idea that physioxia should be an important criterion in determining the microRNA expression level and consequently protein expression and skin functions.

Therefore, when trying to understand the role of microRNAs in skin models, it is important to choose a cell culture system that is as physiological as possible, and have the tools to analyse the different biomarkers (no only microRNA, but also signaling pathways, secretome, etc).

Should you like to have more information on this review, or know what we can do for you to support you with cell culture technologies with controlled oxygen levels or to support you for your biomarker discovery studies, do not hesitate to contact me by leaving a message below.

Source:

(1) Nadim M. et al. “Physioxia and MicroRNAs As Key Factors in the Skin Microenvironment” (2015) FSCC Magazine, Vol. 18 – #1, pp: 35-43

Anti cellulite compound evaluation with in vitro adipocyte-assays

Mechanisms leading to cellulite formation is complex. It involves lipid regulatory pathways and proinflammatory cross-talk that represent promising molecular targets in cosmetology. This post introduces a clever in vitro adipocyte-based assay targeting adipocytokines to better determine the anti cellulite effects of cosmetics compounds.

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Biomarkers and shear stress

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Costaining of pAkt-1S473 (red) and PECAM-1 (green) after 30 min flow-adaptation and 5 min ortho- (D) or retrograde flow (E). Image was obtained using Cat. No. 039200-301-J34L for p-Akt staining.

Research nowadays aims at working on models as similar as possible to the real physiological status. This includes the modification of cell culture conditions, For example, one should perform cell culture under “real” oxygen levels (e.g. hypoxia, normoxia, physioxia). For circulating cells, shear stress is a key factor, as cells behave in a different way depending on whether they are cultured under static or dynamic conditions. [Read more…]

Cellular models to study the Cardiac System (part II)

In a previous post, I introduced several models to study the cardiac human system. This first post introduced human aortic, brachiocephalic, carotid artery and coronary artery cells isolated by Cell Applications Inc. Here is the second part of this inventory of cellular models to study the human cardiac system, where I’ll be highlighting human internal thoracic artery, pulmonary artery, subclavian artery cells, cardiac fibroblasts and cardiomyocytes.

Later on, I’ll conclude this series by part III, referring to animal cellular models for studying the cardiac system. But let’s now concentrate on today’s topic! [Read more…]

mTOR revisited

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Figure taken from Ref. 1.

The PI3K/Akt/mTOR pathway is an intracellular signaling pathway important in regulating the cell cycle. It is directly related to cellular quiescence, proliferation, cancer, and longevity. This pathway can be regulated by genes involved in response to hypoxia. Discoveries that have been made over the last decade show that the mTOR pathway is activated during various cellular processes (e.g. tumour formation and angiogenesis, insulin resistance, adipogenesis and T-lymphocyte activation) and is deregulated in human diseases such as cancer and type 2 diabetes (1). [Read more…]

Cellular models to study the cardiac System (part I)

In this post, I’d like to  introduce human aortic, brachiocephalic, carotid artery and coronary artery cells isolated by Cell Applications Inc. In a future post, I’ll be highlighting human internal thoracic artery, pulmonary artery, subclavian artery cells and cardiomyocytes (now published here).

After taking a look at several cell types as models for studying different aspects of cardiovascular functions and diseases, I’ll cover some recently published results highlighting the importance of securing your primary cells sourcing.

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