Sugar Linked to Alzheimer’s

In a bit of “reverse engineering” research using brain tissues from five people who died with Alzheimer’s disease, Johns Hopkins Medicine researchers say they discovered that a special sugar molecule could play a key role in the development of Alzheimer’s disease. If further research confirms the finding, the molecule, known as a glycan, could serve as a new target for early diagnostic tests, treatments and perhaps prevention of Alzheimer’s disease, say the researchers. Alzheimer’s disease is the most common form of dementia in the United States. Affecting an estimated 5.8 million Americans, the progressive disorder occurs when nerve cells in the brain die due to the buildup of harmful forms of proteins called amyloid and tau.

Cleaning up the disease-causing forms of amyloid and tau is the job of the brain’s immune cells, called microglia. Earlier studies found that when cleanup is impaired, Alzheimer’s disease is more likely to occur. In some people, this is caused by an overabundance of a receptor on the microglia cells, called CD33.

Receptors are not active on their own. Something needs to connect with them to block microglia from cleaning up these toxic proteins in the brain", says Ronald Schnaar,  Professor of Pharmacology at the Johns Hopkins University School of Medicine and director of the laboratory that led the study. Past studies by the researchers showed that for CD33, these “connector” molecules are special sugars. Known to scientists as glycans, these molecules are ferried around the cell by specialized proteins that help them find their appropriate receptors. The protein-glycan combination is called a glycoprotein.

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Targeted delivery of therapeutic RNAs directly to cancer cells

Tel Aviv University‘s groundbreaking technology may revolutionize the treatment of cancer and a wide range of diseases and medical conditions. In the framework of this study, the researchers were able to create a new method of transporting RNA-based drugs to a subpopulation of immune cells involved in the inflammation process, and target the disease-inflamed cell without causing damage to other cells.

The study was led by Prof. Dan Peer, a global pioneer in the development of RNA-based therapeutic delivery. He is Tel Aviv University‘s Vice President for Research and Development, head of the Center for Translational Medicine and a member of both the Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, and the Center for Nanoscience and Nanotechnology. The study was published in the prestigious scientific journal Nature Nanotechnology.

Our development actually changes the world of therapeutic antibodies. Today we flood the body with antibodies that, although selective, damage all the  that express a specific receptor, regardless of their current form. We have now taken out of the equation  that can help us, that is, uninflamed cells, and via a simple injection into the bloodstream can silence, express or edit a particular gene exclusively in the cells that are inflamed at that given moment,” explains Prof. Peer.

As part of the study, Prof. Peer and his team were able to demonstrate this groundbreaking development in animal models of inflammatory bowel diseases such as Crohn’s disease and colitis, and improve all inflammatory symptoms, without performing any manipulation on about 85% of the immune system cells. Behind the innovative development stands a simple concept, targeting to a specific receptor conformation. “On every cell envelope in the body, that is, on the , there are receptors that select which substances enter the cell,” explains Prof. Peer. “If we want to inject a drug, we have to adapt it to the specific receptors on the , otherwise it will circulate in the bloodstream and do nothing. But some of these receptors are dynamic—they change shape on the membrane according to external or internal signals. We are the first in the world to succeed in creating a drug delivery system that knows how to bind to receptors only in a certain situation, and to skip over the other identical cells, that is, to deliver the drug exclusively to cells that are currently relevant to the disease.”

Source: https://phys.org/

How To Reverse Aging in the Brain

The aging global population is the greatest challenge faced by 21st-century healthcare systems. Even COVID-19 is, in a sense, a disease of aging. The risk of death from the virus roughly doubles for every nine years of life, a pattern that is almost identical to a host of other illnesses. But why are old people vulnerable to so many different things?

It turns out that a major hallmark of the aging process in many mammals is inflammation. By that, I don’t mean intense local response we typically associate with an infected wound, but a low grade, grinding, inflammatory background noise that grows louder the longer we live. This “inflammaging” has been shown to contribute to the development of atherosclerosis (the buildup of fat in arteries), diabetes, high blood pressure , frailty, cancer and cognitive decline.

Now a new study published in Nature reveals that microglia — a type of white blood cells found in the brain — are extremely vulnerable to changes in the levels of a major inflammatory molecule called prostaglandin E2 (PGE2). The team found that exposure to this molecule badly affected the ability of microglia and related cells to generate energy and carry out normal cellular processes.

Fortunately, the researchers found that these effects occurred only because of PGE2’s interaction with one specific receptor on the microglia. By disrupting it, they were able to normalize cellular energy production and reduce brain inflammation. The result was improved cognition in aged mice. This offers hope that the cognitive impairment associated with growing older is a transient state we can potentially fix, rather than the inevitable consequence of aging of the brain. Levels of PGE2 increase as mammals age for a variety of reasons — one of which is probably the increasing number of cells in different tissues entering a state termed cellular senescence. This means they become dysfunctional and can cause damage to tissue by releasing PGE2 and other inflammatory molecules.

But the researchers also found that macrophages — another type of white blood cells related to microglia — from people over the age of 65 made significantly more PGE2 than those from young people. Intriguingly, exposing these white blood cells to PGE2 suppressed the ability of their mitochondria — the nearest thing a cell has to batteries — to function. This meant that the entire pattern of energy generation and cellular behavior was disrupted.

Although PGE2 exerts its effects on cells through a range of receptors, the team were able to narrow down the effect to interaction with just one type (the “EP2 receptor” on the macrophages). They showed this by treating white blood cells, grown in the lab, with drugs that either turned this receptor on or off. When the receptor was turned on, cells acted as if they had been exposed to PGE2. But when they were treated with the drugs that turned it off, they recovered. That’s all fine, but it was done in a petri dish. What would happen in an intact body?

The researchers took genetically modified animals in which the EP2 receptor had been removed and allowed them to grow old. They then tested their learning and memory by looking at their ability to navigate mazes (something of a cliche for researchers) and their behavior in an “object location test.” This test is a bit like someone secretly entering your house, swapping your ornaments around on the mantelpiece and then sneaking out again. The better the memory, the longer the subject will spend looking suspiciously at the new arrangement, wondering why it has changed.

It turned out that the old genetically modified mice learned and remembered just as well as their young counterparts. These effects could be duplicated in normal old mice by giving them one of the drugs that could turn the EP2 receptor off for one month. So it seems possible that inhibiting the interaction of PGE2 with this particular receptor may represent a new approach to treating late-life cognitive disorders.

Source: https://www.theconversation.com/

How To Reengineer Viruses To Cure Bacterial Infections

The world is in the midst of a global “superbug crisis. Antibiotic resistance has been found in numerous common bacterial infections, including tuberculosis, gonorrhoea and salmonellosis, making them difficult – if not impossibleto treat. We’re on the cusp of a post-antibiotic era, where there are fewer treatment options for such antibiotic-resistant strains. Given estimates that antibiotic resistance will cause 10 million deaths a year by 2050, finding new methods for treating harmful infections is essential.

Strange as it might sound, viruses might be one possible alternative to antibiotics for treating bacterial infections. Bacteriophages (also known as phages) are viruses that infect bacteria.

They’re estimated to be the most abundant organisms on Earth, with probably more than 1031 bacteriophages on the planet. They can survive in many environments, including deep sea trenches and the human gut. While phages are efficient killers of bacteria, they don’t infect human cells and are harmless to humans.

Although phage therapy was used in the 1930s, it has since become a forgotten cure in the west. Although the treatment became commonplace in the former Soviet Union, it wasn’t adopted by western countries largely because of the discovery of antibiotics, which became widespread after World War II.

Bacteriophages are effective against bacteria because they’re able to attach themselves to the cell if they recognise specific molecules called receptors. This is the first step in the “infection” process. After attaching to the bacterial cell, the phage then injects its DNA inside the bacteria.

This causes one of two things to happen. After being injected with the phage’s DNA, the virus will take over the bacterial cell’s replication mechanism and start producing more phages. This process is known as a “lytic infection”. This disintegrates the cell, allowing the newly produced viruses to leave the host cell to infect other bacterial cells.

But sometimes, the phage DNA gets incorporated into the bacterial host’s chromosome instead, becoming a “prophage. It usually remains dormant but environmental factors, such as UV radiation or the presence of certain chemicals such as those found in sunscreen, can cause the phage to “wake up”, start a lytic infection, take over the host cell and destroy it.

Lytic bacteriophages are preferred for treatment because they don’t integrate into the bacterial host’s chromosome. But it’s not always possible to develop lytic bacteriophages that can be used against all types of bacteria. As each type of phage is only able to infect specific types of bacteria, they can’t infect a bacterial cell unless the bacteriophage can find specific receptors on the bacterial cell surface.

However, engineering techniques can remove the bacteriophage’s ability to integrate into the host’s genome, making them useful for treatment. Engineered phages have even successfully treated a drug-resistant Mycobacterium abscessus infection in a 15-year-old girl.

Source: https://www.realclearscience.com/