Tag: enzymes

Categories : Antibiotics Respiratory DiseasesTags :

New Enzymatic Cocktail can Kill Tuberculosis-causing Mycobacteria

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Mycobacterium tuberculosis drug susceptibility test. Photo by CDC on Unsplash

With resistance to chemical antibiotics on the rise, the world needs entirely new forms of antibiotics. A new study published in Microbiology Spectrum, a journal of the American Society for Microbiology, shows that an enzymatic cocktail can kill a variety of mycobacterial species of bacteria, including those that cause tuberculosis. The research was carried out by scientists at Colorado State University and Endolytix Technologies.

“We have a mycobacterial drug that works for Nontuberculous Mycobacteria and M. tuberculosis that is biological, not phage therapy, and not small molecule antibiotics,” said Jason Holder, Ph.D., a study coauthor and Founder and Chief Science Officer at Endolytix Technology.

“Mycobacterial infections are particularly hard to treat due to poor efficacy with standard of care drugs that are used in multidrug regimens resulting in significant toxicities and treatments lasting 6 months to years. This is often followed up by reemergence of the bacterial infection after a year of testing negative.”

In the new proof of principle study, the researchers took a biological approach instead of a chemical one to develop a cocktail of enzymes that attack the cell envelope of mycobacteria.

The cocktail of enzymes contains highly specific biochemical catalysts that target and degrade the mycobacteria cell envelope that is essential for mycobacterial viability.

To increase efficacy, the researchers delivered the enzymatic drug inside of host macrophages where mycobacteria grow. In laboratory experiments, the drug was effective against M. tuberculosis and Nontuberculous Mycobacteria (NTMs), both lethal pulmonary lung diseases (PD). TB kills roughly 1.5 million people per year.

“We characterised the mechanism of bactericide as through shredding of the bacterial cells into fragments,” Holder said.

“We’ve shown we can design and develop biological antibiotics and deliver them to the sites of infection through liposomal encapsulation. By combining drug delivery science with enzymes that lyse bacteria, we hope to open up treatment options in diseases such as NTM pulmonary disease, tuberculosis pulmonary disease and others.”

According to study coauthor Richard Slayden, PhD, a professor in the Department of Microbiology, Immunology and Pathology at Colorado State University, the new therapy complements current standard-of-care drugs and does not have many of the drug-drug interactions that are problematic with many anti-mycobacterial drugs in use. “Endolytix enzymes work powerfully with standard-of-care antibiotics to kill bacteria with lower drug concentrations,” Holder said. “This has the potential to reduce the significant toxicities associated with multi-drug regimens that are the standard for mycobacterial infections and hopefully lead to more rapid cures.”

Source: American Society for Microbiology

Categories : Medical Research & TechnologyTags :

US Army Scientists Develop Novel Anthrax Treatment

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Capsule removal from Bacillus anthracis by treatment with Capsule Depolymerase (capsule shown in red). Credit: Photomicrograph by Wilson J. Ribot, USAMRIID

By modifying an enzyme produced by the bacterium that causes anthrax, US Army scientists were able to protect mice from infection with the deadly disease. 

Their findings, published in Science Translational Medicine, suggest a potential therapeutic strategy for treating multidrug-resistant strains of anthrax, and could aid in the development of new treatments for other bacterial infections.

Bacillus anthracis, the bacterium that causes anthrax, is one of the most significant bioterrorism threats, as well as a public health challenge in many places around the world. Its disease-causing capability arised from three main components – lethal toxin, oedema toxin, and the capsule. Researchers in this study developed a method to degrade the capsule surrounding the bacterium, allowing it to be ingested and destroyed by white blood cells, reducing virulence.

There is increasing concern about strains of anthrax that appear to be resistant to treatment with known antibiotics, said Arthur M. Friedlander, MD, the paper’s senior author. He and his team explored alternative treatment approaches that do not rely on the use of antibiotic drugs.

One promising avenue is to make the bacterium more susceptible to the innate immune system. Enzymes known as capsular depolymerases, which are naturally produced by several classes of bacteria, have emerged as a potential new line of antivirulence agents.

“Identification of the capsule depolymerase enzyme within the anthrax bacillus led us to attempt to use that enzyme to remove the capsule,” said Friedlander. “When this proved successful, we utilised recombinant DNA technology and protein engineering methods to engineer and reconfigure the enzyme in new ways.”

Those “engineering changes” included enhancing stability and making production easier, and pegylation, to improve pharmacokinetics. The team then tested the pegylated enzyme, known as PEG-CapD-CPS334C, to be sure it had retained its enzymatic activity.

In the study, 10 out of 10 mice infected with anthrax spores from a nontoxigenic encapsulated strain were completely protected after treatment with PEG-CapD-CPS334C, compared to only 1 of 10 control mice surviving. Similarly, treatment of mice infected with a fully virulent encapsulated strain using PEG-CapD-CPS334C protected 8 of 10, while only 2 of 10 controls survived.

“This strategy renders B. anthracis susceptible to the innate immune responses and does not rely on antibiotics,” the authors concluded. “These findings suggest that enzyme-catalysed removal of the capsule may be a potential therapeutic strategy for the treatment of multidrug-resistant anthrax and other bacterial infections.”

It could also allow the treatment of soldiers exposed to anthrax through natural means or enemy attacks.

Source: EurekAlert!

Categories : Metabolic DisordersTags :

Enzyme’s Role in Kidney Disease Could Unlock New Therapies

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Anatomic model of a kidney. Photo by Robina Weermeijer on Unsplash

University of South Australia (UniSA) researchers have discovered that a certain enzyme may help to curb chronic kidney disease, which affects nearly 10% of the world’s population.

This enzyme, known as NEDD4-2, is critical for kidney health, said UniSA Centre for Cancer Biology scientist Dr Jantina Manning.

Chronic kidney disease (CKD) is defined as the presence of kidney damage or reduced filtration rate, persisting for three months or more. It is a state of progressive loss of kidney function ultimately resulting in the need for dialysis or transplantation. 

Dr Manning and her colleagues, including Professor Sharad Kumar, Chair of the UniSA Centre for Cancer Biology, have shown in an animal study that there is a link between a high salt diet, low levels of NEDD4-2 and advanced kidney disease.

While a high salt diet can worsen some forms of kidney disease, it was not previously known that NEDD4-2 is involved in promoting this salt-induced kidney damage.

“We now know that both a high sodium diet and low NEDD4-2 levels promote renal disease progression, even in the absence of high blood pressure, which normally goes hand in hand with increased sodium,” says Dr. Manning.

The NEDD4-2 enzyme regulates the pathway required for sodium reabsorption in the kidneys to ensure correct levels of salt are maintained. If this enzyme is reduced or inhibited, increased salt absorption can result in kidney damage.

Even if people are on a low salt diet, they can get kidney damage if their levels of NEDD4-2 are low due to genetic causes.

Prof Kumar said the goal is to eventually to develop a drug that can raise NEDD4-2 levels in people who have CKD.

“We are now testing different strategies to make sure this protein is maintained at a normal level all the time for overall kidney health,” Prof Kumar said. “In diabetic nephropathy—a common cause of kidney disease—levels of NEDD4-2 are severely reduced. This is the case even when salt is not a factor.”

The study also revealed one other unexpected finding: that kidney disease induced by high salt diets is not always the result of high blood pressure.

“In a lot of cases, kidney disease is exacerbated by hypertension, so we wanted to investigate that link in our study. In fact, we found the complete opposite—that a high salt diet caused excessive water loss and low blood pressure. This is significant because it means that kidney disease can also happen in people who don’t have high blood pressure,” Dr Manning said.

A Lancet paper from 2020 estimated that about 700 million people—about 10% of the world’s population—suffer from chronic kidney disease, and has seen a 29% increase in the past 30 years. This massive surge in CKD is mainly due to the global obesity epidemic. Overweight and obesity lead to diabetes, one of the leading causes of CKD, along with high blood pressure. Between 1980 and 2014 there was a 300% increase in diabetes, according to World Health Organization statistics. This makes it one of the top 10 causes of death worldwide.

“Obesity and lifestyle are two main factors driving chronic kidney disease but there are other things at play as well,” said Dr Manning. “Acute kidney injuries, drugs taken for other conditions, high blood pressure and a genetic predisposition can also cause it.”

Source: Medical Xpress

Journal information: Jantina A. Manning et al. The ubiquitin ligase NEDD4-2/NEDD4L regulates both sodium homeostasis and fibrotic signaling to prevent end-stage renal disease, Cell Death & Disease (2021). DOI: 10.1038/s41419-021-03688-7

Categories : Diseases, Syndromes and Conditions Medical Research & TechnologyTags :

Researchers Study Enzyme Processes for New Drugs

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Traditional discovery has produced drugs that effectively target proteins directly involved with disease, but options are starting to run out and researchers are looking to more complex and obscure interactions for drug targets.

So far, drug discovery has used the ‘small molecule’ approach, where a specific protein is targetted in a cancer cell to shut it down and bring down the cancer cell as a whole. Up until this point, traditional drugs have only been able to target proteins that are involved in the disease that also have activities that are amenable to the small molecule approach, leaving a vast number of proteins unaddressed. Many of these other proteins may be involved in disease processes behind the scenes.

“It’s starting to get to the point where we’ve kind of taken traditional drug discovery as far as we can, and we really need something new,” explained University of Nevada, Las Vegas biochemist Gary Kleiger.

“Cancer cells are clever,” Kleiger said. “They can evolve very, very quickly. So, a drug might be working at first—targeting an enzyme and telling that enzyme, ‘stop doing your activity,’ which can stop the cancer cells from growing. Those cancer cells appear to lie dormant, but all the while there are still little things that happen that eventually enable those cancer cells to bypass that drug.” Therefore, in order to stay ahead of cancer’s capacity to evolve drug resistance, it is necessary to target many additional disease-causing proteins, and thus, limiting the landscape of druggable proteins is a serious disadvantage.

The new approach by investigated by Kleiger and collaborators uses a family of human enzymes called ubiquitin ligases found in human cells. Of about 20 000 known proteins in the human body, some 5-10% are enzymes.

Kleiger’s team uses cutting edge cryo electron microscopes that can image the ubiquitin ligases when they’re at work. To test their hypotheses, Kleiger and collaborators measure the activity of ‘mutated’ enzymes that should now be defective in their activities.

Kleiger compared the process to how a 50 000 year old society might view a bicycle. They could identify its purpose and general properties, but could test the importance of a certain gear; if it was bent, the bicycle would no longer function. “We can do that at the molecular level with the enzymes,” he said.

Source: Medical Xpress

Journal information: Daniel Horn-Ghetko et al, Ubiquitin ligation to F-box protein targets by SCF–RBR E3–E3 super-assembly, Nature (2021). DOI: 10.1038/s41586-021-03197-9