AP Biology class blog for discussing current research in Biology

Tag: neurogenesis

Revealing the Potential of PF4: A Promising Molecule for Rejuvenating Aging Brains

As the global population ages, the quest to preserve cognitive function in older individuals becomes increasingly significant. New research has shed light on a promising candidate in the fight against age-related cognitive decline: platelet factor four (PF4). Studies of three separate techniques have shown that PF4 may play a pivotal role in rejuvenating aging brains, opening the door to potential breakthroughs in the treatment of cognitive decline. 

PBB Protein PF4 image

PF4 Protein

Published on August 16, three research groups reported their findings in Nature Aging, Nature, and Nature Communications. These groups independently investigated techniques to combat cognitive decline in aging individuals, and remarkably, they all found a common factor: increased levels of PF4. This protein, known as platelet factor four, was found to be associated with improved cognitive performance and enhanced biological markers of brain health.

One research group, led by neuroscientist Dena Dubal from the University of California, San Francisco, had initially been studying the hormone klotho, which is linked to longevity. Their earlier studies revealed that injecting Klotho into mice improved cognition. However, because klotho molecules are too large to pass through the blood-brain barrier, the researchers concluded that the hormone must act on the brain indirectly, possibly through a messenger.

In their pursuit to identify this intermediary, Dubal’s team injected mice with klotho and measured changes in protein levels in the animals’ blood. Surprisingly, they discovered that platelet factors, especially PF4, increased significantly.

Another team at the University of California, San Francisco, led by neuroscientist Saul Villeda, had previously demonstrated that blood plasma from young mice could rejuvenate the brains of elderly mice. They found that young plasma contained significantly higher levels of PF4 compared to older plasma. These findings led to a collaboration between these two research teams.

Tara Walker, a neuroscientist at the University of Queensland, Australia, also joined the collaboration, as her team had discovered that exercise boosts PF4 levels and delivering PF4 directly to the brains of mice stimulated the growth of new nerve cells, a process known as neurogenesis, particularly in the hippocampus, a brain region essential for memory.

But what does all this mean?

The results of these studies collectively suggest that PF4, when administered alone, can improve cognition in mice. Additionally, it enhances neurogenesis and neural connections in the hippocampus, potentially explaining the cognitive benefits observed.

Villeda’s team also found a link between PF4 and the immune system. Injecting PF4 into older mice restored their immune systems to a more youthful state, decreasing inflammatory proteins and reducing inflammation in their brains.

While the discovery of PF4’s potential is undoubtedly exciting, there are important caveats to consider. Most notably, translating findings from mice into effective and safe therapies for humans is a considerable challenge. Nevertheless, the observation that PF4 levels decline with age in both mice and humans suggests it may have relevance in the quest to alleviate age-related cognitive decline.

Furthermore, these recent studies represent significant progress, shedding light on one piece of a complex puzzle. Other molecules, like GDF11, have been linked to restorative effects, and researchers are striving to understand their roles better. Lida Katsimpardi, a neuroscientist at the Pasteur Institute in Paris, highlights the need to decipher how each factor fits into the broader picture of cognitive rejuvenation.

The researchers aim to begin human trials within the next few years, but vigilance for potential side effects will be a priority. Additionally, research is essential to precisely understand the mechanisms through which PF4 operates in the body and brain, as well as its potential integration into a broader therapeutic approach.

In  AP Bio class, we’ve began to brush the surface of the topic of neurons. it’s important to grasp that neurons are the fundamental building blocks of the brain’s complex communication network. These brain cells, often referred to as nerve cells, work by transmitting electrical and chemical signals to relay information. According to our AP Bio notes, “the neuron transmits message impulses which communicate information from the environment, process information, and signal parts of the body to respond to the information -all by the flow of chemicals in and out of the plasma membrane”.  As we age, this intricate network can deteriorate, leading to cognitive decline. PF4 facilitates better communication between neurons. This protein’s potential to boost cognitive performance and stimulate the growth of new nerve cells could be the key to maintaining mental vitality as we grow older. While this is still in the early stages of research, the prospect of PF4 as a crucial piece of the cognitive health puzzle is a promising development in our understanding of the brain’s inner workings and its resilience over time. What do you think about the possibilities of PF4? 


Spinal Neurogenesis

An astrocyte cell grown in tissue culture as viewed by Gerry Shaw

Normally, when spinal neurons are lost during life due to disease or injury, they are lost for good, however, thanks to a recent study done by  Zhida Su and his colleagues at the University of Texas Southwestern Medical Center that may no longer be the case. The team took astrocytes—star-shaped support cells in the nervous system— from the spines of living mice and converted them into neurons. This research was based of the previous works of  Marius Wernig from the Stanford University School of Medicine, who first converted rat skin cells into stem cell like cells and then into neurons, Benedikt Berninger from Ludwig Maximillians University Munich, who took certain brain cells and turned them into neurons, and Olof Torper from Lund University, who transformed astroytes from the brains of mice into neurons. Su and his team were drawn to spinal astrocytes because they form scar tissue after spinal cord injuries.

Su and his team accomplished this transformation by injecting a series of viruses into the mice, one of which, SOX2, managed to convert the spinal astrocytes into neuroblasts, both in culture and in living mice who had suffered spinal injuries. Some of these neuroblasts then went on to form functioning neurons and with the addition of valproic acid the number of cells which matured doubled and actually interacted with existing motor neurons.  Although this process is slow and can take up to four weeks, it is incredibly promising and it is even suggested that, “For each reprogrammed [cell], perhaps more than one new neuron could be generated,” meaning that each neuroblast could divide and create multiple neurons. Although this research is extremely promising, only 3-6% of astrocytes effected become neuroblasts which has been in no way enough to study the effects on the health of the mice. However, this research is very young and could lead to major achievments in neurogenesis in the future and the “curing” of paralysis and other conditions that result from the destruction of neurons.

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