New way for derivation / maintenance of naïve human PSCs

Newly added to the Stemolecule portfolio are three small molecules which support a new approach for the derivation and maintenance of naïve human pluripotent stem cells. These three newly identified small molecules, WH-4-023, SB590885 and IM-12, are all kinase inhibitors.


ReproCELL is currently the only stem cell reagent company able to supply all components of the 5i/L/A (5 inhibitors/human LIF/Activin A) media supplement formulation needed for the derivation and maintenance of a “naïve” or ground-state of pluripotency of human cells as referenced in the October 2014 Cell Stem Cell paper by Theunissen et al. out of Dr. Rudolf Jaenisch’s Lab at MIT’s Whitehead Institute. The paper is titled “Systematic identification of culture conditions for induction and maintenance of naïve human pluripotency.”

Stemgent Stemolecule WH-4-023 (SRC Inhibitor)IM-12 Structure

Stemgent Stemolecule SB590885 (BRAF Inhibitor)

Stemgent Stemolecule IM-12 (GSK-3β Inhibitor)


The addition of these three new small molecules consolidates a 5i/L/A media supplement offering in one place. 5i/L/A media supplement consists of 5 kinase inhibitors; WH-4-023 SRC inhibitor, SB590885 BRAF inhibitor, IM-12 GSK-3β inhibitor, PD0325901 MEK inhibitor, Y27632 ROCK inhibitor, recombinant human leukemia inhibitory factor (LIF) and Activin A. The 5i/L/A media supplement allows for the derivation of and conversion of human PSCs to a naïve state of pluripotency hypothesized to be the human equivalent to the mouse ground state of pluripotency.

The Theunissen paper demonstrates the conversion of traditional human epiblastic pluripotent stem cells to a ground state of pluripotency thought to be equivalent to the traditional mouse embryonic stem cell state. The human equivalent to the mouse ground state of pluripotency is termed naïve. Naïve human PSCs differ from traditional human epiblastic ESCs in that human ESCs are FGF/BMP signaling dependent (equivalent to mouse epiblastic stem cells). While naïve PSCs are LIF/Stat3 signaling dependent (equivalent to traditional mouse ESCs). Both traditional mouse ESCs and naïve human PSCs demonstrate higher single cell viability when passaging. Likewise both cell types demonstrate enhanced proliferation when compared to epiblastic stem cells. These attributes make naïve human pluripotent stem cells a good choice for genetic manipulation and gene targeting applications.

Related products used in the paper that researchers may be interested in include: Human recombinant FGF-basic growth factor, CHIR99021 and doxycycline.

New drug for Sickle Cell Disease targets Leukocytes

Leukocytes adhere to blood vessels as a mechanism to enter tissue where there is inflammation. Inadvertently, they pile up sickle cell red blood cells.

Mutations in the hemoglobin gene can render a person to a lifetime of sickle cell disease (SCD). While otherwise healthy individuals with one allele (gene copy) of the sickle hemoglobin (HbS) gene are carriers, the disease is seen in those with two HbS alleles – one inherited from each carrier parent. A single HbS allele can also cause SCD in a person who inherits other defects in the second hemoglobin allele.

[Read more…]

3D monitoring of cell movement through Collagen I

The transition from non-invasive phenotype to invasive phenotype of tumor cells marks the switch from a benign tumor to a more malignant form of cancer. Understanding the mechanisms underlying this hallmark event, which enables tumor cells to invade through Extracellular matrix, is critical for discovering pathways and new targets to develop anti-metastatic strategies. In a previous post, A 96-well Invasion Assay Compatible with High Content Screening, I introduced a technology called Oris™ assays, which employs exclusion zone technology to facilitate unambiguous monitoring of cell migration from the periphery into a central circular detection zone. This assay is a high-throughput assay, but compatible with adherent cells only.  Today I’d like to introduce a new 3D Embedded Invasion Assay, compatible with both non-adherent and adherent cells.

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Imaging techniques compatible with Alvetex 3D culture

As scientists better understand the benefits of growing cells in three dimensions (3D) and routinely adopt 3D culture techniques, methods for visualising cells must also be adapted and optimised.

HaCaT AlvetexThe most common and routinely used technique for tracking two dimensional (2D) cell cultures is light microscopy. Traditional 2D monolayer cultures are highly transparent and within a single optical plane. The minimal light diffraction and diffusion presented by the plastic surface allows the collection of focussed microscopic images. Cells cultured in genuine 3D environments, such as in Alvetex®Scaffold, present some of the same constraints as tissue samples or biopsies, in that simple, live observation of cultures via phase microscopy is not optimal.

There are however, other techniques that can be implemented which will allow the user to monitor culture progress easily and effectively in 3D. [Read more…]

Enriched Tregs for a multitude of research applications

When it comes to the body’s natural defenses, is it possible to have “too much of a good thing”? Absolutely. To spare the host, the immune system needs to distinguish it from the real enemy –infectious agents. Autoimmune disorders occur when this recognition frays and the body’s own cells and tissues are damaged.

That’s where regulatory T cells, or Tregs, come in. [Read more…]

Factors affecting human islet cell quality

The islets of Langerhans are the regions of the pancreas that contain its endocrine (i.e., hormone-producing) cells. Discovered in 1869 by German pathological anatomist Paul Langerhans, the islets of Langerhans constitute approximately 1% to 2% of the mass of the pancreas. There are about one million islets distributed throughout the pancreas of a healthy adult human. Each is separated from the surrounding pancreatic tissue by a thin fibrous connective tissue capsule. The islets of Langerhans contain beta cells, which secrete insulin, and play a significant role in diabetes.

Islets are widely used for transplantation to restore beta cell function from diabetes, offering an alternative to a complete pancreas transplantation or an artificial pancreas. Because the beta cells in the islets of Langerhans are selectively destroyed by an autoimmune process in type 1 diabetes, islet transplantation is a means of restoring physiological beta cell function in patients with type 1 diabetes.

Human Islets for Research (HIR)™ are primary human islets processed from organ donor pancreases that have been approved for research but not for clinical transplantation of either the  pancreas or the isolated islets. HIR™ are obtained in a proprietary process of pancreas digestion and islet purification that results in uniformly high quality HIR™ for delivery to diabetes  investigators. Quality Control (QC) testing is routinely performed prior to release to assure uniform quality and function of these islets available for research. [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…]

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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Alvetex on the International Space Station!

Alvetex Scaffold products allow researchers to overcome the limitations of growing cells on flat surfaces by creating a unique three dimensional (3D) surface that allows cells to form tissue-like structures in an in vitro setting. A team from Massachusetts General Hospital investigating bone loss during bed rest and diseases such as osteoporosis, has incorporated Alvetex Scaffold in experiments 150 miles above the surface of the Earth after the equipment is delivered to the ISS by the SpaceX Dragon capsule. [Read more…]

Cellular models for studying the human urogenital system

The urogenital system is the organ system of the reproductive organs and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways, like the male urethra.

Today, I’ll be taking a look at human primary cells derived from urogenital organs (and in one of my next posts, we’ll explore models for the digestive system.

[Read more…]