Category: New Compounds

A Novel Anticoagulant That can be ‘Deactivated’

Source: NCI

A new biomolecular anticoagulant platform reported in Nano Letters holds promise as a revolutionary advancement over the anticoagulants currently used during surgeries and other procedures. The technology is based around injectable fibre structures which can be quickly dissolved and excreted by the kidneys.

“We envision the uses of our new anticoagulant platform would be during coronary artery bypass surgeries, kidney dialysis, and a variety of vascular, surgical and coronary interventions,” said Kirill Afonin, leader of the team which invented the technology. “We are now investigating if there are potential future applications with cancer treatments to prevent metastasis and also in addressing the needs of malaria, which can cause coagulation issues.”

The team’s technology turns to programmable RNA-DNA anticoagulant fibres that, when injected into the bloodstream, form into modular structures that communicate with thrombin. The technology allows the structures to prevent blood clotting as it is needed and then be quickly eliminated via the renal system once their job is done.

The fibre structures use aptamers, short sequences of DNA or RNA designed to specifically bind and inactivate thrombin.

“Instead of having a single small molecule that deactivates thrombin,” Afonin said, “we now have a relatively large structure that has hundreds of the aptamers on its surface that can bind to thrombin and deactivate them. And because the structure becomes larger, it will circulate in the bloodstream for a significantly longer time than traditional options.”

The extended circulation in the bloodstream allows for a single injection, instead of multiple doses. The design also decreases the concentration of anticoagulants in the blood, resulting in less stress on the body’s renal and other systems, Afonin said.

This technology also introduces a novel “kill-switch” mechanism, which reverses the fibre structure’s anticoagulant function with a second injection. This lets makes the fibres able to be metabolised into materials that are tiny, harmless, inactive and easily excreted by the renal system.

The entire process takes place outside the cell, through extracellular communication with the thrombin. The researchers note that this is important as immunological reactions do not appear to occur, based on their extensive studies.

The team has tested and validated the platform in computer models, human blood and various animal models“We conducted proof-of-concept studies using freshly collected human blood from donors in the US and in Brazil to address a potential inter donor variability,” Afonin said.

The technology may provide a foundation for other biomedical applications that require communication via the extracellular environment in patients, he said. “Thrombin is just one potential application,” he said. “Whatever you want to deactivate extracellularly, without entering the cells, we believe you can. That potentially means that any blood protein, any cell surface receptors, maybe antibodies and toxins, are possible.”

The technique permits the design of structures of any shape desired, with the kill switch mechanism intact. “By changing the shape, we can have them go into different parts of the body, so we can change the distribution,” Afonin said. “It gets an extra layer of sophistication of what it can do.”

While the application is sophisticated, production of the structures is relatively easy. “The shelf life is amazingly good for these formulations,” Afonin said. “They’re very stable, so you can dry them, and we anticipate they will stay for years at ambient temperatures, which makes them very accessible to economically challenged areas of the world.”

Source: University of North Carolina

A Potent New Non-opioid Analgesic

Woman using lab equipment
Source: NCI on Unsplash

Researchers co-led by University of Warwick have discovered a potent new non-opioid analgesic with potentially fewer side effects compared to other potent painkillers.

Their study found that a compound called BnOCPA (benzyloxy-cyclopentyladenosine), is a potent and selective analgesic which is non-addictive. BnOCPA also has a unique mode of action and potentially opens a new pipeline for the development of new analgesic drugs.

The research is published in Nature Communications.

Chronic pain has a negative impact on quality of life and many commonly prescribed analgesics come with side effects. Opioid drugs, such as morphine and oxycodone, can lead to addiction and are dangerous in overdose.

Drugs that act on G protein-coupled receptors (GPCRs) are one possibility, but their development is hampered by the propensity of GPCRs to couple to multiple intracellular signalling pathways. A unique feature of BnOCPA is that it only activates one type of GPCR, leading to very selective effects and thus reducing potential side effects.

University of Warwick’s Dr Mark Wall, who led the research said: “The selectivity and potency of BnOCPA make it truly unique and we hope that with further research it will be possible to generate potent painkillers to help patients cope with chronic pain.”

Source: University of Warwick

Two New Antibody Treatments for Crohn’s Disease Equally Effective

Anatomy of the gut
Source: Pixabay CC0

In a clinical trial, two new antibody treatments for Crohn’s disease were approximately similar in effectiveness, according to findings published in The Lancet.

This allows clinicians and patients to make treatment choices based on tolerance, according to Stephen Hanauer, MD, the Clifford Joseph Barborka Professor and a co-author of the study.

“The safety and efficacy of two agents with different mechanisms of action appears to be quite comparable over one year,” said Prof Hanauer.

Crohn’s disease (CD) is a chronic, progressive inflammatory bowel disease, causing abdominal pain, weight loss and fatigue. Treatment has usually focused on alleviating symptoms to achieve clinical remission using corticosteroids or immunomodulators, but more effective treatment is still needed, according to Prof Hanauer.

‘While there are numerous therapies and mechanisms of action for drugs approved for moderate-severe Crohn’s disease there has been a therapeutic ceiling as far as outcomes are concerned, with usually less than 50% of patients in long-term remission,” Prof Hanauer explained.

Recently, several biologic agents have been approved for use. Adalimumab is a monoclonal antibody that reduces inflammatory cytokines by inhibiting tumor necrosis factor alpha. Ustekinumab is another monoclonal antibody, though the drug targets a different set of proteins: interleukin (IL) 12 and IL-23.

Researchers recruited with Crohn’s disease, randomising 191 to receive ustekinumab and 195 to adalimumab. Patients reaching clinical remission were similar between both groups: 65% of 191 patients in the ustekinumab group versus 61% of 195 in the adalimumab group. There were no deaths through one year of study, though slightly more patients in the ustekinumab group discontinued study treatment. Disease severity measures decreased similarly over the study.

Both treatment regimens resulted in clinical remission with similar toxicity profiles.

“There are numerous options for patients with moderate-severe disease. However, the key is to treat patients with an effective regimen and treat to targets as early in the course as possible since we do not have any drugs that impact on fibrosis once it occurs,” Prof Hanauer said.

Source: Northwestern University

Cancer Drug Candidate Spurs Nerve Regeneration

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A candidate cancer drug currently in development has been also shown to stimulate regeneration of damaged nerves after spinal trauma. Four weeks after spinal cord injury, animals treated with the candidate drug, AZD1390, were “indistinguishable” from uninjured animals, according to the researchers.

The study, published in Clinical and Translational Medicine, demonstrated in cell and animal models that the candidate drug, AZD1390, can block the response to DNA damage in nerve cells and promote regeneration of damaged nerves. This restored sensory and motor function after spinal injury.

The announcement comes weeks after the same research team showed a different investigational drug, AZD1236, can reduce damage after spinal cord injury, by blocking the inflammatory response.

AZD1390 is also under investigation by AstraZeneca to block ATM-dependent signalling and repair of DNA double strand breaks (DSBs), an action which sensitises cancer cells to radiation treatment. The ATM protein kinase pathway – a critical biochemical pathway regulating the response to DNA damage. The DNA Damage Response system (DDR) is activated by DNA damage, including DSBs in the genome, which also happen in several common cancers and also after spinal cord injury.

Professor Zubair Ahmed, from the University’s Institute of Inflammation and Ageing and Dr Richard Tuxworth from the Institute of Cancer and Genomic Sciences hypothesised the persistent activation of this system may prevent recovery from spinal cord injury, and that blocking it would promote nerve repair and restore function after injury.

Their initial studies found that AZD1390 stimulated nerve cell growth in culture, and inhibited the ATM protein kinase pathway – a critical biochemical pathway regulating the response to DNA damage.

AZD1390 was tested in animal models following spinal cord injury. Oral treatment with AZD1390 significantly suppressed the ATM protein kinase pathway, stimulated nerve regeneration beyond the site of injury, and improved the ability of these nerves to carry electrical signals across the injury site.

Professor Ahmed commented: “This is an exciting time in spinal cord injury research with several different investigational drugs being identified as potential therapies for spinal cord injury. We are particularly excited about AZD1390 which can be taken orally and reaches the site of injury in sufficient quantities to promote nerve regeneration and restore lost function.

“Our findings show a remarkable recovery of sensory and motor functions, and AZD1390-treated animals being indistinguishable from uninjured animals within 4 weeks of injury.”

Dr Tuxworth added: “This early study shows that AZD1390 could be used as a therapy in life-changing conditions. In addition, repurposing this existing investigational drug potentially means we can reach the clinic significantly faster than developing a new drug from scratch.”

Source: University of Birmingham

The Search for New Cancer Therapies Strikes Gold

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The gold complex auranofin has traditionally been used for treating rheumatism but is also being evaluated as a one number of new cancer therapies. According to a study published in Redox Biology, molecules with the same inhibition effect have been discovered that have a more specific effect than auranofin and therefore may have greater potential as cancer therapies.

Auranofin (AF) is classed by the WHO (World Health Organization) as an anti-rheumatic agent and is an active component in the drug Ridaura. AF is also currently being assayed in a string of clinical trials as a possible cancer therapy. One reason for the researchers’ interest in AF is its ability to inhibit thioredoxin reductase (TrxR), a protein central to the thioredoxin system, which protects cells from oxidative stress in all mammals. 

However, TrxR also protects cancer cells, making cancer therapies less effective. Moreover, TrxR, which affects cellular growth and survival, is upregulated in certain forms of cancer.

“There’s a great deal of interest in the ability to inhibit the thioredoxin system in the treatment of cancer, but there’s a risk that healthy cells will also be damaged and killed,” says the study’s co-last author Elias Arnér, professor at the Department of Medical Biochemistry and Biophysics at Karolinska Institutet. “Our aim is for TrxR inhibitors to be as specific as possible.”

The researchers studied the effects of AF in mouse cancer cells (lung adenocarcinoma and melanoma) and compared them with other recently-developed TrxR-inhibiting molecules called TRi-1 and TRi-2 (thioredoxin reductase inhibitors 1 and 2). 

The study, which was based on new proteomic methods of analysing the entire set of proteins in cells, suggests that the TRi compounds are more specific in their effect than AF. The results show that AF causes very high levels of oxidative stress and has other effects that seem unrelated to the inhibition of TrxR. They also demonstrate that TRi-1 seems to be the most specific TrxR inhibitor so far.

“Our results can serve as an important blueprint for further studies of AF’s mechanism of action and side effects,” said the study’s other co-last author Roman Zubarev, professor at the Department of Medical Biochemistry and Biophysics, Karolinska Institutet. “Having now compared AF with the more specific molecules TRi-1 and TRi-2, we hope that our findings will contribute to the further development of TrxR inhibitors as anticancer drugs.”

Source: Karolinska Insitutet

New Antibacterial Molecules Identified

Source: National Cancer Institute on Unsplash

Researchers have identified a new group of molecules with an antibacterial effect against many antibiotic-resistant bacteria. Since the properties of the molecules can easily be altered chemically, the hope is to develop new, effective antibiotics with few side effects. The study appears in PNAS.

Increasing antibiotic resistance is a great concern as few new antibiotics have been developed in the past 50 years.

Most antibiotics work by inhibiting the bacteria’s ability to form a protective cell wall, causing the bacteria to crack (cell lysis). Besides the well-known penicillin, which inhibits enzymes building up the wall, newer antibiotics such as daptomycin or the recently discovered teixobactin bind to a special molecule, lipid II. All bacteria need lipid II as a building block for the cell wall. Antibiotics that bind to Lipid II are usually very large and complex molecules and therefore more difficult to improve with chemical methods. These molecules are in addition mostly inactive against a group of problematic bacteria, which are surrounded by an additional layer, the outer membrane, that hinders penetration of these antibacterials.

“Lipid II is a very attractive target for new antibiotics. We have identified the first small antibacterial compounds that work by binding to this lipid molecule, and in our study, we found no resistant bacterial mutants, which is very promising,” says Birgitta Henriques Normark, professor at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, and one of the article’s three corresponding authors.

For this study, published in PNAS, researchers tested a large number of chemical compounds for their ability to lyse pneumococci – the most common cause of community-acquired pneumonia. After a careful follow-up of active compounds from this screening, the researchers found that a group of molecules called THCz inhibits the formation of the cell wall of the bacterium by binding to lipid II. The molecules could also prevent the formation of the sugar capsule that pneumococci need to escape the immune system and to cause disease.

Small molecules offer several benefits, noted Fredrik Almqvist, professor at Umeå University and one of the corresponding authors: “The advantage of small molecules like these is that they are more easy to change chemically. We hope to be able to change THCz so that the antibacterial effect increases and any negative effects on human cells decrease.”

Laboratory work with THCz showed it has an antibacterial effect against many antibiotic-resistant bacteria, such as methicillin-resistant staphylococci (MRSA), vancomycin-resistant enterococci (VRE), and penicillin-resistant pneumococci (PNSP). An antibacterial effect was also found against gonococci, which causes gonorrhoea, and mycobacteria, bacteria that can cause severe diseases such as tuberculosis in humans. None of the bacteria managed to develop resistance to THCz in a laboratory environment.

“We will now also initiate attempts to change the THCz molecule, allowing it to penetrate the outer cell membrane found in some, especially intractable, multi-resistant bacteria,” says Tanja Schneider, professor at the Institute of Pharmaceutical Microbiology at the University of Bonn and one of the corresponding authors.

Source: Karolinska Institutet

Native American Plant Remedies Found to Have Dual Properties

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Following a functional screen of extracts from US plants researchers found that plants with a long history of use by Native Americans as topical analgesics were often also used as gastrointestinal aids.

The study, published today in Frontiers in Physiology, found forest plants that activated the KCNQ2/3 potassium channel, a protein that passes electrical impulses in the brain and other tissues, showed a long history of use by Native Americans as topical analgesics, to treat conditions such as insect bites, stings, sores and burns. Less intuitively, the same plants that activated KCNQ2/3 and were used as traditional painkillers were often also used as gastrointestinal aids, especially for preventing diarrhoea.

“Done in collaboration with the US National Parks Service, this study illustrates how much there is still to learn from the medicinal practices of Native Americans, and how, by applying molecular mechanistic approaches we can highlight their ingenuity, provide molecular rationalizations for their specific uses of plants, and potentially uncover new medicines from plants,” said UCI School of Medicine professor Geoffrey Abbott, PhD.
KCNQ2/3 is present in nerve cells that sense pain, and activating it would relieve pain by reducing pain signal transmission. The breakthrough \came when the team discovered that the same plant extracts that activate KCNQ2/3 have an opposite effect on the related intestinal potassium channel, KCNQ1-KCNE3. Previous studies on modern medicines showed that KCNQ1-KCNE3 inhibitors can prevent diarrhoea.

The Abbott Lab is currently screening native US plants, having shown already that quercetin and tannic and gallic acids explained many of the beneficial effects of the plants. The team also identified binding sites on the channel proteins that produce the effects.

Knowing that these compounds activate versus inhibit closely related human ion channel proteins, drug specificity and safety can be improved and therefore safety. More specifically, the plant compounds can be further optimised with the goal of treating pain and secretory diarrhoea.

“I personally am very excited about the paper; it was my lab’s first published collaboration with the National Park Service, and it shines a light on the incredible ingenuity and medicinal wisdom of Californian Native American tribes,” said Prof Abbott.

New analgesics are being sought to fight the opioid crisis. In addition, according to the CDC, diarrhoeal diseases account for 1 in 9 child deaths worldwide; incredibly, diarrhoea kills over 2000 children every day worldwide – more than AIDS, malaria and measles combined.

Source: University of California – Irvine

An End to The ‘Therapeutic Drought’ in Atopic Dermatitis

Source: NCI

The end of a longstanding “therapeutic drought” in atopic dermatitis (AD) is in sight as improved understanding of the pathogenesis and pathophysiology has stoked development of multiple drug candidates, according to a leading expert in the field.

“We did have treatments like cyclosporine, that are not specific as we know, and they are not treatments we can give our patients for long-term disease control,” said Emma Guttman-Yassky, MD, of the Icahn School of Medicine at Mount Sinai, during the Inflammatory Skin Diseases Summit.

She said that overcoming this drought was not easy, mostly because “we didn’t have enough understanding of the disease and its pathogenesis, really preventing therapeutic development for patients with atopic dermatitis,” she said.

New AD therapies built on the trail made for psoriasis treatment, starting with basic studies that produced insights into pathogenesis, leading to hypotheses that eventually could be tested in clinical trials, she said. Progress was accompanied by many failures in early stages of therapeutic development in psoriasis.

“One failure that I remember very vividly from psoriasis was the failure of interferon-gamma targeting,” Dr Guttman-Yassky recounted. “In atopic dermatitis, we also had our share of this type of failure, but these failures really helped shape therapeutic directions for all the diseases we are now targeting, including atopic dermatitis.”

This rocky development has led to recognition that AD is a complex disease involving multiple pathogenetic components, including barrier dysfunction, immune abnormalities, disruption of the dermal microbiome, and the peripheral and central nervous systems that play a central role in itch and other disease manifestations.

“Of all the major components involved in AD pathogenesis, immune targeting is the most tractable,” said Dr Guttman-Yassky. “Immune abnormalities are the most important because they perpetuate the disease phenotype of atopic dermatitis, from the nonlesional skin to acute disease and chronic lesions.”

In contrast to psoriasis, AD is a more heterogeneous disease with multiple clinical phenotypes that correlate with differences in immune polarisation and barrier dysfunction. All of the phenotypes exhibit activation of the type 2 inflammatory pathway as a common feature. Across the spectrum of clinical phenotypes, additional cytokine targeting may be required to achieve disease control.

Understanding that AD arises from systemic inflammation has also helped therapy development. Several studies have suggested that, compared to psoriasis, AD is associated with higher levels of immune activation. Blood samples of patients with AD have shown increased levels of activated T cells, circulatory cytokines, and cardiovascular markers.
The accumulation of new insights into AD pathogenesis added no fewer than a dozen viable therapeutic candidates to the pipeline. Dupilumab (Dupixent) led the way in providing the proof of principle that Th2-specific targeting reverses key pathogenetic factors that drive the disease process in AD.

Dr Guttman-Yassky pointed out how targeting Th2 inflammation with dupilumab led to reversal of barrier defects and lichenisation typical of AD as early as 4 weeks, and that by 16 weeks lesional and nonlesional skin looked similar. Furthermore, markers of epidermal hyperplasia and proliferation were “completely wiped out.”

Dr Guttman-Yassky highlighted several key classes of AD drug candidates with potential to build on the success of targeting inflammation: Interleukin-13 inhibition, OX40 inhibition and JAK/STAT inhibition, which showed promising results.

“With these types of response rates, our treatment goals for our patients are evolving,” said Dr Guttman-Yassky.

Source: MedPage Today

New Drug Targets for Memory Loss

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Researchers have identified specific drug targets within memory-encoding neural circuits, opening up possibilities for new treatments of a range of brain disorders.

Memory loss is a main feature of a number of neurological and psychiatric disorders including Alzheimer’s disease and schizophrenia. Presently, there are few, very limited memory loss treatments and the search for safe and effective drug therapies has, until now, borne little fruit.

The research was done in collaboration with colleagues at the international biopharmaceutical company Sosei Heptares. The findings, published in Nature Communications, identify specific receptors for the neurotransmitter acetylcholine that re-route information flowing through memory circuits in the hippocampus. Acetylcholine is released in the brain during learning and is critical for the acquisition of new memories. Until now, the only effective treatment for the symptoms of cognitive or memory impairment seen in diseases such as Alzheimer’s is using drugs that broadly boost acetylcholine. However, this leads to multiple adverse side effects. The discovery of specific receptor targets that have the potential to provide the positive effects whilst avoiding the negative ones is promising.

Lead author Professor Jack Mellor from the University of Bristol’s Center for Synaptic Plasticity, said: “These findings are about the fundamental processes that occur in the brain during the encoding of memory and how they may be regulated by brain state or drugs targeting specific receptor proteins. In the long-term, the discovery of these specific targets opens up avenues and opportunities for the development of new treatments for the symptoms of Alzheimer’s disease and other conditions with prominent cognitive impairments. The academic-industry partnership is important for these discoveries and we hope to continue working together on these projects.”

Dr Miles Congreve, Chief Scientific Officer at Sosei Heptares, added: “These important studies have helped us to design and select new, exquisitely targeted therapeutic agents that mimic the effects of acetylcholine at specific muscarinic receptors, without triggering the unwanted side effects of earlier and less-well targeted treatments. This approach has the exciting potential to improve memory and cognitive function in patients with Alzheimer’s and other neurological diseases.”

“It is fascinating how the brain prioritises different bits of information, working out what is important to encode in memory and what can be discarded. We know there must be mechanisms to pull out the things that are important to us but we know very little about how these processes work. Our future program of work aims to reveal how the brain does this using acetylcholine in tandem with other neurotransmitters such as dopamine, serotonin and noradrenaline,” said Professor Mellor.

Source: University of Bristol

Breakthrough Could Lead to New Opioid Alternatives

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Monash University researchers have made a breakthrough discovery that might lead to new non-opioid analgesics to treat neuropathic pain safely and effectively, without the risk of opioid addictions.

Neuropathic pain occurs when nerves are damaged or dysfunctional, and can be caused by injury, virus infection or cancer treatment, or it can be a symptom or complication of conditions such as multiple sclerosis and diabetes.

The new study, published in Nature, has shown a new mode of targeting the adenosine A1 receptor protein, which had long been a promising therapeutic target for non-opioid painkillers to treat neuropathic pain. However, development of analgesics using it had failed due to a lack of sufficient on-target selectivity, as well as undesirable adverse effects.

In the study, Monash researchers used electrophysiology and preclinical pain models to show that a particular class of molecule, called a ‘positive allosteric modulator’ (PAM), can enhance the targeting of the A1 receptor by binding to a different region of the protein.

Another breakthrough in the study was observing the high-resolution structure of the A1 receptor bound to both its natural activator, adenosine, and an analgesic PAM, which was facilitated by the application of cryo electron microscopy (cryoEM), providing the first atomic level snapshot of the drug binding location.

Chronic pain remains a widespread global health burden. A lack of treatment options has led to over-reliance on opioid painkillers, which provide only limited relief in patients with chronic (particularly neuropathic) pain, while having severe adverse effects, such as respiratory depression and addiction. In 2016, 42 000 deaths related to opioid misuse were recorded in the US, while 25 million Americans suffer from chronic pain.

This new discovery opens the door to the development of non-opioid drugs that lack such side effects.

Co-corresponding author of the study and Dean of the Faculty of Pharmacy and Pharmaceutical Sciences, Professor Arthur Christopoulos said: “The world is in the grip of a global opioid crisis and there is an urgent need for non-opioid drugs that are both safe and effective.”

Source: Monash University