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@CoassoloEtAl_2025_ProhormoneCleavagePredictiona

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Reference

Coassolo, L., B. Danneskiold-Samsøe, N., Nguyen, Q., Wiggenhorn, A., Zhao, M., Wang, D. C.-H., Toomer, D., Lone, J., Wei, Y., Patel, A., Liparulo, I., Kavi, D., Wat, L. W., Reghupaty, S. C., Kim, J. J., Asemi, T., Bielczyk-Maczynska, E., Li, V. L., Moya-Garzon, M. D., … Svensson, K. J. (2025). Prohormone cleavage prediction uncovers a non-incretin anti-obesity peptide. Nature, 1–10. https://doi.org/10.1038/s41586-025-08683-y

Blue: Important conclusions

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Prohormone convertase 1/3 (also known as PCSK1/3) represents a key enzymatic mechanism in peptide processing, as exemplified with the therapeutic target glucagon-like peptide 1 (GLP-1)1,2

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we use computational drug discovery to systematically map more than 2,600 previously uncharacterized human proteolytic peptide fragments cleaved by prohormone convertases, enabling the identification of novel bioactive peptides

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12-mer peptide, BRINP2-related peptide (BRP)

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BRP reduces food intake and exhibits antiobesity effects in mice and pigs without inducing nausea or aversion

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BRP administration triggers central FOS activation and acts independently of leptin, GLP-1 receptor and melanocortin 4 receptor

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Thus, in contrast to many known anorexigenic peptides, BRP action is independent of GLP1R, leptin and MC4R.

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BRP activation is consistent with Gαs-coupled GPCR activation leading to pCREBS133 and Fos activity in neuronal cells (Fig. 4p).

Yellow: Interesting

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Peptide hormones are a class of small (fewer than 100 amino acids), low-abundance molecules

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PCSK1 variants have been identified as important genetic factors in human obesity1 and have been associated with hyperphagia in both mice21,22 and humans1,23.

  • PCSK1 es una proteasa implicada en el procesamiento de las prohormonas hacia su forma activa. Se expresa en células neuroendrocrinas y está directamente implicada en la biosíntesis de insulina. La PCSK2 está más ligada al glucagón.

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Many peptides, including the known metabolic regulator and therapeutic target GLP-114,24,25, are created through the activity of PCSK1 and other subtilisin-like proprotein convertases such as PCSK2 and furin19,20.

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The largest group of predicted peptides with distinct tissue expression (423 peptides) originated from the brain, and the second largest group (322) originated from the liver

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BRP (THRILRRLFNLC) is flanked by KK and KR cleavage sites, which are recognized by proconvertases, releasing the peptide from its 78-kDa secreted parent protein BRINP2

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In mice, humans and pigs, BRINP2 is predominantly expressed in the brain (Extended Data Fig.3a–c), but its function44 is distinct from that of BRP

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BRP did not induce pica, as measured by kaolin intake in rats, whereas cisplatin induced significant kaolin intake (Fig. 2t). Finally, we performed a conditioned taste aversion test to determine whether BRP administration causes aversion and nausea-related sickness responses. We found that BRP did not induce aversion to saccharin, whereas LiCl did (Fig. 2u).

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  • la administracion de brp o liraglutida (analogo semaglutida Novo) produce anorexia y perdida de peso.

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effect of BRP in minipigs, a relevant model of human feeding behaviour

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we tested whether BRP requires intact GLP1R, leptin or MC4R, well-established central pathways for appetite regulation.

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BRP activated regions in the hypothalamus, but did not activate FOS in the hindbrain or brainstem (Fig. 5d,e). In the hypothalamus, BRP induced significant activation of FOS in the dorsomedial hypothalamic nucleus, preoptic hypothalamic nucleus, tuberal nucleus and arcuate nucleus (Fig. 5f–h and Extended Data Fig. 9e–g).

Green: Agree with the paper

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we generated Peptide Predictor, a code for sequence pattern recognition using Regular Expression (RegEx) to match text patterns of protein sequences that contain the posttranslational proteolytic dibasic cleavage residues recognized by PCSK enzymes—KR/RR/RK/KK—followed by a non-basic, non-aliphatic amino acid

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enriches for precursors with a high density of cleavage sites, such as pre-proglucagon (Fig. 1c). Out of the 2,082 secreted proteins in the human secretome, we identified 373 precursors that generated 2,683 peptides (Fig. 1d). Bioactivity predictors indicate that between 21% and 23% of Peptide Predictor-derived peptides are bioactive

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Given that mRNA expression levels of the immediate early gene Fos is linked to the bioactivity of peptides41,42, we chose to measure Fos expression in the neuronal Neuroscreen-1 (NS-1) cell line and the β-cell line INS1 (Fig. 1i). As expected, we found that GLP-1(7–37) induced an increase of around threefold in Fos expression in INS1 cells, and neuronal growth factor (NGF) induced an increase of around tenfold in Fos expression in NS-1 cells (Fig. 1i).

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we identified BRP, a 12-residue peptide derived from BRINP2 that induced Fos expression by more than tenfold in both cell lines (Fig. 1i)

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We next performed in vivo studies to determine whether any of the top-scoring peptides controlled food intake or blood glucose levels.

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BRP potently and immediately suppressed food intake, an effect that lasted up to 3 h

  • efecto de semaglutida??? cuanto dura?

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Repeated injections of BRP or scrambled BRP over 48 h showed that BRP resulted in reduced overall food intake (Extended Data Fig.6a,b) owing to a reduction in meal frequency (Extended Data Fig.6c) and an increase in time between meals (Extended Data Fig. 6d) but not meal size

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On days when the pigs received the peptide, BRP lowered food intake by 50% at 1 h (Fig. 2x). Notably, the anorectic effect of BRP in minipigs was similar to that of liraglutide (Fig. 2y,z)

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In light of the 20–50% reduced food induced by BRP in wild-type mice, we tested whether BRP could reverse metabolic disease in mice with established obesity and diabetes

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The effect of liraglutide on initial body weight loss was greater than that of BRP (Fig. 3c). BRP-treated mice had improved glucose (Fig. 3f) and insulin tolerance (Fig. 3g), an effect accompanied by lower fasting glucose (Fig. 3f,g) and lower fasting insulin levels (Extended Data Fig. 8c).

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At the 5 mg kg−1 dose, GLP-1 suppressed obesity as efficiently as 2.5 mg kg−1 BRP (Fig. 3m,n). Finally, we performed EchoMRI body composition analysis. After 14 days of treatment, during which mice lost significant body weight (Fig. 3o), BRP resulted in a significant loss of fat mass (Fig. 3p) but no loss of lean mass (Fig. 3q)

  • ojo que perdemos grasa pero no masa muscular.

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The top hit in response to BRP was CREB phosphorylated at S133 (pCREBS133), a phosphorylation site that is often induced by extracellular stimuli51 (Fig. 4a)

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Temporally, BRP induced phosphorylation of pCREBS133, pERK1/2T202/Y204 and protein kinase A (PKA) substrate after 15 min and up to 60 min of BRP exposure (Fig. 4d). Both PKA and CREB are activated by cyclic adenosine monophosphate (cAMP)

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BRP activated pCREBS133 signalling only in the brain and not in the peripheral organs such as the liver, iWAT, skeletal muscle or pancreas, supporting a central role for BRP

  • como penetra la barrera hematoencefálica? cómo lo hacen GLP1?

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BRP suppressed food intake when delivered by intraperitoneal (10 mg kg−1), intranasal (10 mg kg−1) and intracerebroventricular (0.5 mg kg−1) injection (Fig. 5a–c). Note that intracerebroventricular administration of BRP at a 20× lower dose (compared with intraperitoneal administration) caused a significant reduction of food intake, supporting a central action of BRP

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RP activates a subset of POMC-negative neurons in the arcuate nucleus

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BRP activates a central CREB–FOS signalling pathway in POMC-negative hypothalamic neurons.

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Mechanistically, BRP stimulates the cAMP–PKA–CREB–FOS pathway in neuronal cells and activates FOS in the hypothalamus.

  • cual es el circuito de GLP1?? Es distinto de este?

Red: Disagree with the paper

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The half-life of BRP in plasma was less than 10 min

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we found that the Arg-Arg sequence in BRP is a putative cleavage site, as the two cleaved fragments—THRIL and LFNLC—were detected in plasma after BRP administration (Extended Data Fig.2m) but were biologically inactive in suppressing food intake

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this appetite-suppressing effect was similar to that of GLP-1 (Supplementary Tables 7, 9 and 10). However, in contrast to GLP-1, BRP did not demonstrate any pancreatic activity, as blood glucose levels (Extended Data Fig. 2s) and insulin secretion (Extended Data Fig. 2t) remained unchanged.

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the action of GLP-1 was blocked with a GLP1R antagonist, exendin(9–39); however, the anorectic effect of BRP was sustained in the presence of exendin(9–39), strongly suggesting that BRP and GLP-1 act through distinct receptors

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However, although BRP treatment reversed obesity and showed similar efficacy to GLP-1 in mouse studies, the physiological functions of endogenous BRP in mice and humans remain to be determined. Posttranslational cleavage enables rapid processing and release of mature, active peptides locally or into circulation in response to nutritional or metabolic changes. BRP is detected locally in the brain and CSF, but it is not known how the levels change with nutrient deprivation or excess.

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The use of knockout mice to study cleaved peptides is difficult because the therapeutic effects of small peptide fragments such as BRP may not be reflected in mice lacking the parent protein (that is, BRINP2).

Purple: To learn more

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the reduction in body weight was entirely owing to loss of fat mass.

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the neuronal populations responsible for the BRP-induced food intake suppression remain to be determined.

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Competing interests K.J.S. and L.C. are named inventors on patents regarding BRP peptides for metabolic disorders. K.J.S. is a co-founder of Merrifield Therapeutics. All other authors declare no competing interests.

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