Coupland, C. ; Sun, N. ; Khalil, A. ; Karaoglu, Ö.E. ; Liskiewicz, A. ; Liskiewicz, D. ; Grandl, G. ; Akindehin, S.E. ; Maity-Kumar, G. ; Yang, B.* ; Finan, B.* ; Knerr, P.J.* ; Douros, J.D.* ; Walch, A.K. ; DiMarchi, R.* ; Tschöp, M.H. ; Müller, T.D. ; Novikoff, A.
Estrogenic activity of E2-conjugated GLP-1 is mediated by intracellular endolysosomal acidification and estrone metabolism.
Mol. Metab. 96:102136 (2025)
Recent modifications to glucagon-like peptide 1 (GLP-1), known for its insulinotropic and satiety-inducing effects, have focused on conjugating small molecules to enable selective delivery into GLP-1R+ tissues to achieve targeted synergy and improved metabolic outcomes. Despite continued advancements in GLP-1/small molecule conjugate strategies, the intracellular mechanisms facilitating concurrent GLP-1R signaling and small molecule cargo release remain poorly understood. We evaluate an estradiol (E2)-conjugated GLP-1 (GLP-1-CEX/E2) for relative differences in GLP-1R signaling and trafficking, and elucidate endolysosomal dynamics that lead to estrogenic activity using various live-cell, reporter, imaging, and mass-spectrometry techniques. We find GLP-1-CEX/E2 does not differentially activate or traffic the GLP-1R relative to its unconjugated GLP-1 backbone (GLP-1-CEX), but uniquely internalizes the E2 moiety and stimulates estrogenic signaling. Endolysosomal pH-dependent proteolytic activity likely mediates E2 moiety liberation, as evidenced by clear amplification in estrogenic activity following co-administration with lysosomal VATPase activator EN6. The hypothesized liberated metabolite from GLP-1-CEX/E2, E2-3-ether, exhibits partial estrogenic efficacy through ERα, and is predisposed toward estrone-3-sulfate conversion. Finally, we identify relative increases in intracellular E2, estrone, and estrone-3-sulfate following GLP-1-CEX/E2 incubation in GLP-1R+ cells, demonstrating proof-of-principle for desired cargo release. Together, our data suggest that GLP-1-CEX/E2 depends on GLP-1R trafficking and lysosome acidification for estrogenic efficacy, with a likely conversion of the liberated E2-3-ether metabolite into estrone-3-sulfate, resulting in residual downstream flux into active estradiol. Our current findings aim to improve the understanding of small molecule targeting and the efficacy behind GLP-1/small molecule conjugates.
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Article: Journal article
Document type
Scientific Article
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Keywords
Bioluminescent Resonance Energy Transfer (bret) ; Estradiol ; Glucagon-like Peptide 1 ; Metabolomics ; Peptide Conjugation ; Pharmacology; Insulin-secretion; Glucagon; Sulfate; Camp; Dysfunction; Reverses; Cells
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Language
english
Publication Year
2025
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0
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2025
ISSN (print) / ISBN
2212-8778
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2212-8778
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Volume: 96,
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Article Number: 102136
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Elsevier
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Amsterdam
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Peer reviewed
POF-Topic(s)
30201 - Metabolic Health
30205 - Bioengineering and Digital Health
90000 - German Center for Diabetes Research
Research field(s)
Helmholtz Diabetes Center
Enabling and Novel Technologies
PSP Element(s)
G-502200-001
G-500390-001
G-502296-001
G-501900-221
G-502200-006
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Erfassungsdatum
2025-05-10