By admin 
In a significant stride towards addressing the global obesity epidemic, researchers at Stanford Medicine have unearthed a naturally occurring molecule that demonstrates remarkable potential in appetite suppression and body weight reduction. This novel peptide, known as BRP, appears to mimic the profound weight-loss effects seen with semaglutide, the active ingredient in popular medications like Ozempic, but critically, without several of its common and often debilitating side effects, including nausea, constipation, and substantial muscle loss. This discovery, detailed in a recent issue of Nature, represents a potential paradigm shift in the development of safer and more targeted obesity therapeutics.
The molecule, BRP (BRINP2-related-peptide), operates through a distinct yet related metabolic pathway compared to semaglutide, activating a separate, more focused group of neurons within the brain. This crucial mechanistic difference could position BRP as a more precise and potentially superior tool for controlling appetite and managing body weight, offering hope for millions struggling with obesity and its associated health complications.
A More Targeted Approach to Appetite Control
The fundamental distinction lies in BRP’s specificity. As explained by assistant professor of pathology Katrin Svensson, PhD, the senior author of the research, "The receptors targeted by semaglutide are found in the brain but also in the gut, pancreas and other tissues. That’s why Ozempic has widespread effects including slowing the movement of food through the digestive tract and lowering blood sugar levels." Semaglutide, a GLP-1 receptor agonist, leverages receptors that are broadly distributed throughout the body, leading to its multi-faceted effects on metabolism, but also contributing to its gastrointestinal side effects.
In stark contrast, BRP appears to act specifically within the hypothalamus, a small but immensely powerful region nestled deep within the brain. This vital area serves as the central command center for numerous critical bodily functions, including hunger regulation, satiety signaling, body temperature control, hormone activity, and overall energy expenditure. By primarily influencing this region, BRP holds the promise of modulating appetite and metabolism with greater precision, potentially circumventing the widespread systemic effects that contribute to the side effect profile of current GLP-1 receptor agonists. This targeted approach could unlock a new era of "precision medicine" for obesity, where treatments are designed to act where they are most needed, minimizing off-target effects.
Dr. Svensson’s commitment to translating this groundbreaking research into clinical reality is evident; she has co-founded a company with plans to initiate human clinical trials of the BRP molecule in the near future, marking an exciting transition from laboratory discovery to potential patient benefit. Senior research scientist Laetitia Coassolo, PhD, is recognized as the lead author of this pivotal study, underscoring the collaborative effort behind this scientific breakthrough.
Artificial Intelligence Reveals Hidden Peptides
The discovery of BRP was not a serendipitous accident but a testament to the power of cutting-edge artificial intelligence. The research team harnessed AI’s capabilities to systematically sift through vast biological data, allowing them to identify specific proteins belonging to a group known as prohormones.
Prohormones are fascinating molecular precursors – inactive compounds that do not exert their final biological function until they are cleaved by specialized enzymes into smaller, biologically active fragments called peptides. Some of these peptides then function as hormones, acting as vital chemical messengers that carry signals influencing metabolism, appetite, and other complex physiological processes throughout the brain and the rest of the body. The complexity arises from the fact that a single prohormone can be cut in multiple ways, yielding a multitude of possible peptides. Identifying the few genuine peptide hormones among a sea of ordinary fragments, often created during routine protein processing and breakdown, has historically been an arduous and often overwhelming task for traditional laboratory methods. These methods, while effective, generate colossal amounts of data, forcing researchers to meticulously sort through hundreds of thousands of molecules in search of the rare few with meaningful biological effects. This "needle in a haystack" problem has long hindered the discovery of novel peptide hormones.
Searching for New Metabolic Signals
The Stanford team strategically focused their search on an enzyme called prohormone convertase 1/3 (PC1/3). This enzyme is known for its precise ability to cleave prohormones at specific amino acid sequences and has previously been implicated in human obesity, making it a prime candidate for investigation.
One of the most well-known peptides produced through the action of PC1/3 is glucagon-like peptide 1, or GLP-1. GLP-1 is a crucial endogenous hormone that plays a significant role in regulating hunger, satiety, and blood sugar levels. Semaglutide, the active ingredient in Ozempic and Wegovy, works by mimicking the effects of this natural GLP-1 in the body, which explains its efficacy in managing both type 2 diabetes and obesity.
The researchers astutely reasoned that if PC1/3 produced GLP-1, it might also be responsible for generating other peptides that influence energy balance and appetite. To systematically explore this hypothesis and overcome the limitations of traditional methods, they innovatively turned to artificial intelligence.
Peptide Predictor: A Game-Changing Algorithm
Instead of the laborious and time-consuming process of manually extracting proteins and peptides from tissues and then using techniques like mass spectrometry to identify enormous numbers of molecules, the researchers developed a sophisticated computer algorithm named Peptide Predictor.
This powerful program systematically scanned all 20,000 human protein-coding genes, specifically searching for the types of cleavage sites where prohormone convertase 1/3 typically cuts proteins. To further refine their search, the researchers narrowed the field to genes that produce proteins secreted outside the cell – a common characteristic of hormones – and that contained at least four possible cleavage sites. This intelligent filtering process dramatically reduced the candidate pool to a much more manageable group of 373 prohormones, transforming an intractable problem into a focused investigation.
"The algorithm was absolutely key to our findings," Svensson emphasized, highlighting the indispensable role of AI in accelerating this discovery. Peptide Predictor estimated that prohormone convertase 1/3 could potentially produce an astonishing 2,683 distinct peptides from these 373 prohormones. From this extensive list, Coassolo and Svensson meticulously focused on sequences that, based on their computational predictions and biological understanding, seemed most likely to exert effects within the brain, particularly in areas associated with appetite and metabolism.
They then selected a curated list of 100 peptides, including the well-established GLP-1, and proceeded to test their ability to stimulate neuron-like cells grown in the laboratory. This in vitro screening was the critical first step in identifying functionally active peptides.
A Tiny Peptide With an Outsized Effect
The results of the cellular screening were compelling. As anticipated, GLP-1 strongly activated the neuronal cells, significantly increasing their activity to three times the level observed in untreated control cells. This validated their experimental setup and confirmed the known activity of GLP-1.
However, the real surprise came from a much smaller peptide that produced an even more dramatic response. This tiny molecule, composed of only 12 amino acids, elicited an astounding tenfold increase in neuronal activity compared with controls. This exceptionally potent response from such a small peptide immediately flagged it as a prime candidate for further investigation.
The researchers named this potent peptide BRP, an acronym derived from its parent prohormone, BPM/retinoic acid inducible neural specific 2, or BRINP2. The fact that a molecule containing only 12 amino acids – an extremely small size compared to most full-sized proteins – could produce the strongest response in these initial cell tests was a strong indicator of its potential biological significance.
Food Intake Fell by Up to 50% in Animal Models
With promising in vitro data, the team advanced to testing BRP in live animal models. They conducted experiments in both lean mice and minipigs, the latter being particularly valuable because their metabolism and eating patterns more closely mirror those of humans, offering a better translational model.
The results were striking: an intramuscular injection of BRP administered before feeding reduced food intake during the subsequent hour by as much as 50% in both species. This rapid and substantial reduction in food consumption underscored BRP’s powerful anorexigenic (appetite-suppressing) effects.
To evaluate its long-term effects on body weight and metabolic health, the team administered daily BRP injections to obese mice for a period of 14 days. The treated animals, on average, lost a significant 3 grams of body weight, with nearly all of this reduction attributable to a decrease in body fat. In contrast, mice in the control group, which did not receive BRP, gained approximately 3 grams over the same two-week period. This 6-gram differential highlights BRP’s potent fat-specific weight loss capabilities.
Beyond weight loss, the treated mice also exhibited improved glucose and insulin tolerance. These critical metabolic measures reflect the body’s efficiency in regulating blood sugar levels and its responsiveness to insulin, the hormone responsible for transporting glucose from the bloodstream into cells for energy. Improved tolerance indicates enhanced metabolic health, a crucial benefit for individuals with obesity who are often at higher risk for type 2 diabetes.
No Clear Signs of Common Side Effects
Perhaps one of the most exciting aspects of BRP’s profile is its apparent lack of the common side effects associated with existing weight loss treatments like semaglutide. Behavioral testing in treated animals revealed no meaningful differences compared to untreated controls in parameters such as movement, water consumption, anxiety-like behavior, or fecal production.
The absence of changes in fecal production was particularly noteworthy, as semaglutide is known to slow gastric emptying, often leading to constipation and other gastrointestinal disturbances. Furthermore, the researchers did not observe any nausea-related responses in the animals, a frequently reported and often distressing side effect of GLP-1 agonists. Crucially, the study also found no evidence of major muscle loss, a growing concern with some current weight loss medications, where a portion of the weight lost can unfortunately be lean muscle mass rather than just fat. Preserving muscle mass is vital for maintaining metabolic health, strength, and overall well-being during weight loss.
Additional measurements of brain activity and body function further confirmed that BRP acts through distinct metabolic and neuronal pathways that differ from those activated by GLP-1 or semaglutide. These findings strongly suggest that BRP reduces appetite and body weight through a more focused biological route, offering a potentially cleaner side-effect profile. While these results are currently limited to animal studies, they provide a compelling rationale for advancing BRP into human trials.
Questions Before Human Testing
Despite the highly promising animal data, several critical questions remain before BRP can be safely and effectively translated for human use. The researchers are now diligently working to identify the specific cell-surface receptors that BRP binds to. Receptors are molecular structures that act as docking stations for hormones, drugs, and other chemical messengers. Pinpointing the exact receptor BRP utilizes will be fundamental to fully understanding its precise mechanism of action and how it ultimately influences appetite and metabolism at a molecular level.
The team also aims to meticulously map the full sequence of downstream events that occur once BRP binds to its target receptor. This detailed understanding of its signaling cascade will be crucial for optimizing its therapeutic potential and predicting any unforeseen effects.
Another significant challenge inherent to small peptides like BRP is their duration of action. Peptides are often quickly broken down by enzymes in the body, which can shorten their therapeutic effects. The researchers are actively investigating strategies to enhance BRP’s stability and prolong its half-life, with the goal of developing a formulation that could be administered on a more practical schedule for human patients, perhaps once a day or even less frequently.
"The lack of effective drugs to treat obesity in humans has been a problem for decades," Svensson remarked, underscoring the profound unmet medical need. "Nothing we’ve tested before has compared to semaglutide’s ability to decrease appetite and body weight. We are very eager to learn if it is safe and effective in humans." The global prevalence of obesity has reached epidemic proportions, affecting hundreds of millions worldwide and contributing significantly to the burden of chronic diseases such as type 2 diabetes, cardiovascular disease, certain cancers, and musculoskeletal disorders. The development of safe, effective, and well-tolerated weight loss therapies is therefore a public health imperative.
Researchers from the University of California, Berkeley; the University of Minnesota; and the University of British Columbia made valuable contributions to this collaborative work, highlighting the interdisciplinary nature of modern scientific discovery.
The study received generous funding from multiple sources, including the National Institutes of Health (grants R01DK125260, P30DK116074, K99AR081618 and GM113854), the SPARK Translational Research Program at Stanford, Stanford Bio-X, the Stanford Maternal and Child Health Research Institute, the American Heart Association, a Stanford Medicine Dean’s Fellowship Award, the Carlsberg Foundation, and the Wu Tsai Human Performance Alliance.
Dr. Svensson and Dr. Coassolo are inventors on patents related to BRP peptides for metabolic disorders, indicating the commercial potential and intellectual property generated by this research. Furthermore, Dr. Svensson is a co-founder of Merrifield Therapeutics, a company poised to translate these promising findings into clinical development, marking a pivotal step towards bringing BRP to patients in need. This pioneering work offers a beacon of hope for a future where obesity can be managed with therapies that are not only highly effective but also exceptionally well-tolerated.
