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19 Search Results for "Addiction Science"

Mood-Altering Messenger Goes Nuclear

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Serotonin

Serotonin is best known for its role as a chemical messenger in the brain, helping to regulate mood, appetite, sleep, and many other functions. It exerts these influences by binding to its receptor on the surface of neural cells. But startling new work suggests the impact of serotonin does not end there: the molecule also can enter a cell’s nucleus and directly switch on genes.

While much more study is needed, this is a potentially groundbreaking discovery. Not only could it have implications for managing depression and other mood disorders, it may also open new avenues for treating substance abuse and neurodegenerative diseases.

To understand how serotonin contributes to switching genes on and off, a lesson on epigenetics is helpful. Keep in mind that the DNA instruction book of all cells is essentially the same, yet the chapters of the book are read in very different ways by cells in different parts of the body. Epigenetics refers to chemical marks on DNA itself or on the protein “spools” called histones that package DNA. These marks influence the activity of genes in a particular cell without changing the underlying DNA sequence, switching them on and off or acting as “volume knobs” to turn the activity of particular genes up or down.

The marks include various chemical groups—including acetyl, phosphate, or methyl—which are added at precise locations to those spool-like proteins called histones. The addition of such groups alters the accessibility of the DNA for copying into messenger RNA and producing needed proteins.

In the study reported in Nature, researchers led by Ian Maze and postdoctoral researcher Lorna Farrelly, Icahn School of Medicine at Mount Sinai, New York, followed a hunch that serotonin molecules might also get added to histones [1]. There had been hints that it might be possible. For instance, earlier evidence suggested that inside cells, serotonin could enter the nucleus. There also was evidence that serotonin could attach to proteins outside the nucleus in a process called serotonylation.

These data begged the question: Is serotonylation important in the brain and/or other living tissues that produce serotonin in vivo? After a lot of hard work, the answer now appears to be yes.

These NIH-supported researchers found that serotonylation does indeed occur in the cell nucleus. They also identified a particular enzyme that directly attaches serotonin molecules to histone proteins. With serotonin attached, DNA loosens on its spool, allowing for increased gene expression.

The team found that histone serotonylation takes place in serotonin-producing human neurons derived from induced pluripotent stem cells (iPSCs). They also observed this process occurring in the brains of developing mice.

In fact, the researchers found evidence of those serotonin marks in many parts of the body. They are especially prevalent in the brain and gut, where serotonin also is produced in significant amounts. Those marks consistently correlate with areas of active gene expression.

The serotonin mark often occurs on histones in combination with a second methyl mark. The researchers suggest that this double marking of histones might help to further reinforce an active state of gene expression.

This work demonstrates that serotonin can directly influence gene expression in a manner that’s wholly separate from its previously known role in transmitting chemical messages from one neuron to the next. And, there are likely other surprises in store.

The newly discovered role of serotonin in modifying gene expression may contribute significantly to our understanding of mood disorders and other psychiatric conditions with known links to serotonin signals, suggesting potentially new targets for therapeutic intervention. But for now, this fundamental discovery raises many more intriguing questions than it answers.

Science is full of surprises, and this paper is definitely one of them. Will this kind of histone marking occur with other chemical messengers, such as dopamine and acetylcholine? This unexpected discovery now allows us to track serotonin and perhaps some of the brain’s other chemical messengers to see what they might be doing in the cell nucleus and whether this information might one day help in treating the millions of Americans with mood and behavioral disorders.

Reference:

[1] Histone serotonylation is a permissive modification that enhances TFIID binding to H3K4me3. Farrelly LA, Thompson RE, Zhao S, Lepack AE, Lyu Y, Bhanu NV, Zhang B, Loh YE, Ramakrishnan A, Vadodaria KC, Heard KJ, Erikson G, Nakadai T, Bastle RM, Lukasak BJ, Zebroski H 3rd, Alenina N, Bader M, Berton O, Roeder RG, Molina H, Gage FH, Shen L, Garcia BA, Li H, Muir TW, Maze I. Nature. 2019 Mar 13. [Epub ahead of print]

Links:

Any Mood Disorder (National Institute of Mental Health/NIH)

Drugs, Brains, and Behavior: The Science of Addiction (National Institute on Drug Abuse/NIH)

Epigenomics (National Human Genome Research Institute/NIH)

Maze Lab (Icahn School of Medicine at Mount Sinai, New York, NY)

NIH Support: National Institute on Drug Abuse; National Institute of Mental Health; National Institute of General Medical Sciences; National Cancer Institute


Researchers Elucidate Role of Stress Gene in Chronic Pain

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Credit: Getty Images/simonkr

For most people, pain eventually fades away as an injury heals. But for others, the pain persists beyond the initial healing and becomes chronic, hanging on for weeks, months, or even years. Now, we may have uncovered an answer to help explain why: subtle differences in a gene that controls how the body responds to stress.

In a recent study of more than 1,600 people injured in traffic accidents, researchers discovered that individuals with a certain variant in a stress-controlling gene, called FKBP5, were more likely to develop chronic pain than those with other variants [1]. These findings may point to new non-addictive strategies for preventing or controlling chronic pain, and underscore the importance of NIH-funded research for tackling our nation’s opioid overuse crisis.


All Scientific Hands on Deck to End the Opioid Crisis

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Word cloudIn 2015, 2 million people had a prescription opioid-use disorder and 591,000 suffered from a heroin-use disorder; prescription drug misuse alone cost the nation $78.5 billion in healthcare, law enforcement, and lost productivity. But while the scope of the crisis is staggering, it is not hopeless.

We understand opioid addiction better than many other drug use disorders; there are effective strategies that can be implemented right now to save lives and to prevent and treat opioid addiction. At the National Rx Drug Abuse and Heroin Summit in Atlanta last April, lawmakers and representatives from health care, law enforcement, and many private stakeholders from across the nation affirmed a strong commitment to end the crisis.

Research will be a critical component of achieving this goal. Today in the New England Journal of Medicine, we laid out a plan to accelerate research in three crucial areas: overdose reversal, addiction treatment, and pain management [1].


Widening Gap in U.S. Life Expectancy

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Map of life expectancies

Caption: Life expectancy at birth by county, 2014. Life expectancy into 80s (blue), 70s (green, yellow, orange), 60s (red).

Americans are living longer than ever before, thanks in large part to NIH-supported research. But a new, heavily publicized study shows that recent gains in longevity aren’t being enjoyed equally in all corners of the United States. In fact, depending on where you live in this great country, life expectancy can vary more than 20 years—a surprisingly wide gap that has widened significantly in recent decades.

Researchers attribute this disturbing gap to a variety of social and economic influences, as well as differences in modifiable behavioral and lifestyle factors, such as obesity, inactivity, and tobacco use. The findings serve as a sobering reminder that, despite the considerable progress made possible by biomedical science, more research is needed to figure out better ways of addressing health disparities and improving life expectancy for all Americans.

In the new study published in JAMA Internal Medicine, a research team, partially funded by NIH, found that the average American baby born in 2014 can expect to live to about age 79 [1]. That’s up from a national average of about 73 in 1980 and around 68 in 1950. However, babies born in 2014 in remote Oglala Lakota County, SD, home to the Pine Ridge Indian Reservation, can expect to live only about 66 years. That’s in stark contrast to a child born about 400 miles away in Summit County, CO, where life expectancy at birth now exceeds age 86.


Cool Videos: Flashes of Neuronal Brilliance

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When you have a bright idea or suddenly understand something, you might say that a light bulb just went on in your head. But, as the flashing lights of this very cool video show, the brain’s signaling cells, called neurons, continually switch on and off in response to a wide range of factors, simple or sublime.

The technology used to produce this video—a recent winner in the Federation of American Societies for Experimental Biology’s BioArt contest—takes advantage of the fact that whenever a neuron is activated, levels of calcium increase inside the cell. To capture that activity, graduate student Caitlin Vander Weele in Kay M. Tye’s lab at the Picower Institute for Learning and Memory, Massachusetts Institute of Technology (MIT), Cambridge, MA, engineered neurons in a mouse’s brain to produce a bright fluorescent signal whenever calcium increases. Consequently, each time a neuron was activated, the fluorescent indicator lit up and the changes were detected with a miniature microscope. The brighter the flash, the greater the activity!


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