LKT Labs

Biochemicals for Life Science Research

Home | kdonnay

kdonnay

Baricitinib: Inhibitor of JAK-STAT Pathway

Baricitinib inhibits Janus kinases 1 and 2. These kinases are the first enzymes of the JAK-STAT signaling pathway. This pathway is important for many cell functions. Disorders of JAK-STAT can play a role in cancer and immune disease. For example, baricitinib, a JAK-STAT signaling disrupter, is approved in Europe to treat rheumatoid arthritis.

Progeria and JAK-STAT

Recently, researchers at the Technical University of Munich using a text mining approach had suspicions that a rare premature aging disorder, Hutchinson-Gilford progeria syndrome, is associated with the JAK-STAT pathway. It is known that this syndrome has four main symptoms that mimic normal aging: vascular disease, arthritis, lipodistrophy, and alopecia. In most cases of this disease, a single de novo mutation is responsible for causing the production of progerin, leading to a shortened life span. Unfortunately, sufferers rarely live past the age of thirteen.

The research team decided to run a literature meta-analysis on genes associated with each symptom of progeria. In all, seventeen genes implicated in all four symptoms were found, and of those seventeen, fourteen were part of the JAK-STAT pathway.

Baricitinib Inhibits Janus Kinases

Henceforth, to test the role of the JAK-STAT pathway in progeria experimentally, the team grew cells in culture from progeria patients and also from unaffected controls. The progeric cells expressed abnormal levels of the fourteen identified genes. When the researchers applied baricitinib to the cell culture, the gene expression levels normalized. After one month of baricitinib treatment, progeric cells were less likely to become senescent.

Furthermore, etoposide was also applied to the cell culture, which is known to worsen cell senescence. As anticipated, etoposide treatment disrupted expression of the fourteen genes.

In conclusion, this research shows that the JAK-STAT pathway is likely part of the Hutchinson-Gilford progeria disease mechanism, and baricitinib may have potential as a therapy.

 

Liu C, Arnold R, Henriques G, et al. Inhibition of JAK-STAT signaling with baricitinib reduces inflammation and improves cellular homeostasis in progeria cells. Cells. 2019 Oct 18;8(10):1276. doi: 10.3390/cells810276. PMID: 31635416.

Impact of 2-DG on Triple-Negative Breast Cancers

Triple-negative breast cancers present a difficult problem. Most existing therapies for breast cancer target hormone receptors on the cell surface to inhibit cell division. As such, breast cancers that lack these receptors, known as triple-negative cancers, are harder to treat. Physicians need more pharmaceutical options for treating these cancers.

A Possibility?

One promising molecule is 2-Deoxy-D-Glucose, which takes advantage of cancer cells’ altered metabolism. Some types of cancer cells depend on glycolysis as their source of energy, rather than oxidative phosphorylation, and so require more glucose than normal cells, which depend on oxidative phosphorylation for energy. Interestingly, 2-Deoxy-D-glucose is a toxic glucose analog that enters cells through normal glucose transporters. The toxicity should be more impactful to cancer cells than to normal cells because of the increased rate of uptake.

One Team’s Investigation

Recently, a team of researchers in Dublin tested 2-Deoxy-D-glucose’s effectiveness at treating breast cancer. They hypothesized that if 2-Deoxy-D-glucose worked as expected, then it should be more toxic to more aggressive, metabolically active cancers than less aggressive ones.

They tested two breast cancer cell lines, Hs578T, and its more aggressive variant, Hs578Ts(i)8. 2-Deoxy-D-glucose reduced the ability of the breast cancer cells to spread and migrate in vitro. The more aggressive cell line was more affected.

Normally when epithelial cells such as breast cancer travel through the blood or lymph system, they undergo apoptosis. Hence, cancer cells must have resistance to apoptosis in order to metastasize. The researchers tested the lines’ resistance to apoptosis. 2-Deoxy-D-glucose reduced the ability of the aggressive cell line to metastasize, but not the less aggressive one. Further evidence also suggests that the cancer stem cells present were directly affected by 2-Deoxy-D-Glucose treatment, in both cell lines.

Therefore, these results suggest that 2-Deoxy-D-glucose has the potential to treat triple-negative breast cancer, particularly the more aggressive variant in this study. Further studies may have a positive impact on developing treatments for the most aggressive and difficult to treat triple-negative breast cancers.

O’Neill S, Porter RK, McNamee N, et al. 2-Deoxy-D-Glucose inhibits aggressive triple-negative breast cancer cells by targeting glycolysis and the cancer stem cell phenotype. Sci Rep. 2019. 9:3788. doi: 10.1038/s41598-019-39789-9. PMID: 30846710.

 

 

Promising Mycobacteria Treatment: Bedaquiline

Bedaquiline, a potential treatment for several kinds of mycobacteria, was the first new drug to be approved for the treatment of tuberculosis in forty years back in 2012. This drug is especially important for the treatment of multidrug-resistant tuberculosis when first line treatments fail. It works by preventing the mycobacterium from making ATP, which is a different mechanism from older treatments.

Bedaquiline has attracted interest from public health researchers for the treatment of non-tuberculous mycobacteria. These bacteria infect lungs and wounds, especially in immunocompromised patients. In rich countries, non-tuberculous mycobacterial infections cause a greater health burden than tuberculosis itself does. These infections are difficult to treat because, as with tuberculosis, no effective drugs have been developed recently.

Researchers at the University of Texas Health Science Center have begun investigating the potential for developing a new treatment for this type of infection using bedaquiline. To begin, they first collected isolates of non-tuberculous mycobacteria from lungs and wounds of infected patients and grew them in nutrient broth. The isolates were then tested using broth microdilution antimicrobial susceptibility testing (AST). They calculated the minimum amount of bedaquiline they needed to add to the broth to inhibit bacterial growth, the minimum inhibitory concentration. They found that the required concentrations should be achievable in patients’ blood, so bedaquiline has potential to treat non-tuberculous mycobacterial infections.

In considering bedaquiline for the treatment of mycobacteria, researchers caution that bedaquiline should not be used as a monotherapy, because of the potential for bacteria to develop resistance.

 

Bedaquiline Fumarate

 

Brown-Elliot BA, Wallace RJ. 2018. In vitro susceptibility testing of bedaquiline against mycobacterium absceccus complex. Antimicrobial Agents and Chemotherapy. 29:63(2). doi: 10.1128/AAC.01919-18. PMID: 30509936

 

Now that you’ve read about it, find out how to pronounce it too!

 

Okadaic Acid for Alzheimer’s Research

New discoveries are one step closer with a new application using okadaic acid in Alzheimer’s research. Alzheimer’s disease is difficult to model in non-human animals. Recently, a collaboration between Indian and American researchers proposed a treatment combination that could produce rats with more biomarkers of Alzheimer’s disease than previous models.

Hypoxia increases the amount of misfolded amyloid beta aggregates in the brain, a well-known biomarker of Alzheimer’s disease. However, hypoxia does not cause tau tangles, which is another biomarker of Alzheimer’s disease. Okadaic acid is a toxin that is known for causing diarrhetic shellfish poisoning. It selectively inhibits phosphatases, so it is often used as a research chemical to study phosphorylation. As it turns out, in the brain it hyperphosphorylates tau, which causes it to tangle.

A combination of hypoxia and okadaic acid treatment therefore should produce rats with more biomarkers of Alzheimer’s disease than either treatment alone.

This collaborative research team microinjected okadaic acid into live rat brains, then placed the rats in a hypoxic chamber with 10% oxygen (atmosphere contains about 21%) for three days. The treated rats fared worse at an electrical shock avoidance test and a water maze memory test.

The team then sacrificed the rats and analyzed their brain biochemistry. As predicted, hypoxia increased the amount of amyloid beta aggregates in the rat brains, and okadaic acid increased the number of hyperphosphorylated tau tangles. Rats that received the combination treatment also had decreased acetylcholine esterase activity and increased oxidative damage, which are also biochemical hallmarks of Alzheimer’s disease.

This combination treatment of hypoxia plus okadaic acid in rats should be useful for further advancing the research into Alzheimer’s disease.

 

Okadaic Acid

Okadaic Acid Ammonium

Okadaic Acid Sodium

 

Kaushal A, Wani WY, Bal A, Gill KD, Kaur J. Okadaic acid and hypoxia induced dementia model of Alzheimer’s type in rats. 2019. Neurotoxicity Research.  PMID: 30729451

 

 

The Metabolic Impact of Kynurenic Acid

Background

Kynurenic acid is a metabolite of tryptophan. This chemical is found throughout the body, and appears to act on glutamate receptors in the brain. One effect of Kynurenic acid on Gpr35 signaling that has been discovered is enhanced cellular respiration.

Interestingly, high levels of kynurenic acid have been found in the brains of patients with schizophrenia. Further research is ongoing to understand its role in that disease. Less is known about its role in the rest of the body.

Kynurenic Acid Combined with Consistent Exercise and Feeding

One relationship that has been discovered is that exercise causes the levels of kynurenic acid to increase in skeletal muscle. Recently, Agudelo et al. sought to tease the effects of kynurenic acid on metabolism apart from the effects of exercise alone.

To accomplish this, mice were dosed with kynurenic acid without changing their exercise habits. Their metabolisms then sped up, but their level of exercise and feeding stayed the same. As a result, the mice lost some weight after two weeks, which came from a reduction in their white fat stores.

Kynurenic Acid Combined with Altered Diets and Genetics

Previous research has shown that kynurenic acid activates the receptor protein Gpr35. Agudelo et al. wanted to test whether Gpr35 was involved in the relationship between kynurenic acid and metabolism.

To test the effect of Kynurenic acid on Gpr35 signaling, they put mice on a high-fat diet that causes them to gain weight. When they dosed the mice on the high-fat diet with kynurenic acid, they prevented the mice from gaining weight.

When they dosed mice that lack Gpr35 with kynurenic acid, the mice gained weight as usual. These results suggest that Gpr35 signaling is important for kynurenic acid’s role in raising metabolism.

 

In conclusion, this study increases the understanding of both kynurenic acid and Gpr35. A therapeutic application for kynurenic acid is a long way off, but worth studying.

 

K977545  Kynurenic Acid

 

Agudelo LZ, Ferreia DMS, Cervenka I, et al. Kynurenic acid and Gpr35 regulate adipose tissue energy homeostasis and inflammation. 2018. Cell Metabolism. 27(2):378-392. PMID: 29414686.

Recombinant AMPs May Be More Effective Antibacterials

Background:

Antimicrobial peptides (AMPs) are short strings of amino acids, about 12-50 residues long, that show potent antibacterial, antiviral, and antifungal activity. They are found throughout the tree of life as part of the innate immune system. Many AMPs are in clinical use, such as vancomycin.

A class of AMPs called the cecropins were first isolated from the moth Hyalophora cecropia. Magainins were first isolated from the frog Xenopus laevis. An analog of magainin went through clinical trials as a treatment for infected diabetic foot ulcers, but failed.

Research Inspiration:

Researchers from the Jilin Agricultural University in China are interested in developing AMPs for livestock feed as an alternative to antibiotics. Previous research suggested that the fusion of peptides from two AMPs may enhance their antibacterial activity. Zhang et al. decided to test the properties of a magainin II – cecropin B fusion.

The group was also interested in testing whether the fungus Cordyceps militaris would make a suitable expression vehicle for fusion proteins. They constructed a plasmid that coded for the magainin II – cecropin B fusion and transformed cordyceps to express it. Then they extracted protein from the transformed fungus.

New Testing:

They tested the extract using ELISA, PAGE, and Western blotting and found that the cordyceps did express the fusion protein. Then, they swabbed the protein onto plates containing various species of bacteria to test whether it inhibited bacterial growth. Magainin II – cecropin B inhibited bacterial growth better than cecropin B alone.

The researchers also administered magainin II – cecropin B to mice infected with E. coli. The fusion inhibited E. coli growth in the mouse gut, and the mice suffered less intestinal damage. The same effect was observed when they fed the transformed cordyceps straight to the mice.

Zhang et al. conclude that magainin II – cecropin B is an effective antimicrobial. Cordyceps militaris that expresses magainin II – cecropin B could potentially be added to livestock feed.

 

C1609 Cecropin B
M0124 Magainin 1
M0126 Magainin 2

 

Zhang M, Shan Y, Gau H, Wang B, Liu X, Dong Y, Liu X, Yao N, Zhou Y, Li X, Li H. Expression of a recombinant hybrid antimicrobial peptide magainin II-cecropin B in the mycelium of the medicinal fungus Cordyceps militaris and its validation in mice. 2018. Microb Cell Fact. 17:18. PMID: 29402269.