In:
Science, American Association for the Advancement of Science (AAAS), Vol. 381, No. 6657 ( 2023-08-04)
Abstract:
Gut microbiota can regulate the physiology and pathophysiology of the host by producing enzymes with functions similar to those of the host. However, it is difficult to identify these microbial-host isozymes through sequencing-based studies because enzymes with similar functions in different species may lack sequence conservation. An activity-based functional protein screening framework is more reliable for the discovery and characterization of such microbial-host isozymes, which will help yield deeper insights into the gut microbiota–host cross-talk. RATIONALE To identify potential microbial-host isozymes, we set up an enzyme activity screening platform, including activity assays for 110 enzymes that are functional in various human diseases. These enzyme activities were measured in stool-derived ex vivo bacteria communities. Dipeptidyl peptidase 4 (DPP4) was a prominent microbial-host isozyme identified in our screen, but little is known about its pathophysiological effects on the host. We sought to determine whether gut microbial–derived DPP4, like host DPP4 (hDPP4), could decrease active GLP-1 and thus affect blood glucose homeostasis. RESULTS We identified 71 enzymes with positive activity in the human gut bacteria communities through our enzyme activity screening platform, most of which were validated in the protein extracts obtained from feces of germ-free and specific pathogen–free mice. Among these identified enzymes, DPP4 activity had the highest statistical effect size ( Z factor) among the 10 human samples. Through human gut bacteria isolation and DPP4 activity screening, we discovered that microbial DPP4 was mainly produced by Bacteroides spp. Gut microbial DPP4 (mDPP4) could degrade active GLP-1(7-37) in vitro. However, mDPP4 could not affect active GLP-1 levels in chow-fed mice but could decrease active GLP-1 activity and impair glucose homeostasis in high-fat diet (HFD)–fed mice or dextran sulfate sodium/indomethacin–treated mice, suggesting that a damaged gut barrier is required for mDPP4 to affect the activity of host GLP-1. We discovered that the clinical DPP4 inhibitor sitagliptin failed to efficiently inhibit mDPP4. And by solving the co-crystal of mDPP4 with sitagliptin at 1.97-anstrom resolution, we found differences in the nature of the binding between the drug and mDPP4 compared with its binding to hDPP4 that may explain this difference in inhibitory effects. A sitagliptin clinical trial ( www.clinicaltrials.gov identifer NCT04495881) among patients with type 2 diabetes (T2D) ( n = 57) and a related fecal microbiota transplant of stool from high responders and low responders in the present study to HFD-fed mice demonstrated that mDPP4 could limit the efficacy of sitagliptin in individuals with T2D and in glucose-intolerant mice. To identify a selective inhibitor of mDPP4, we screened ~107,000 compounds, and using structural modification we identified Dau-d4, a derivative of daurisoline, that could selectively inhibit mDPP4 activity compared with hDPP4. Dau-d4 could increase active GLP-1 levels and improve glucose metabolism in diabetic mice, and co-administration of Dau-d4 with sitagliptin further improved blood glucose homeostasis. CONCLUSION Here, we developed an activity-based strategy to identify uncharacterized gut microbial-host isozymes that provides a deeper understanding of gut microbiota–host interactions. Gut microbial DPP4 isozyme can impair host glucose homeostasis, and variations in microbial DPP4 activities could possibly contribute to the heterogeneous responses to sitagliptin observed among patients with T2D. Our findings highlight the promise of developing therapies that target both host and gut microbial enzymes to achieve greater clinical efficacy. Discovery and inhibition of a gut microbial–host isozyme to regulate host metabolism. Differences in the gut microbiota may explain why some individuals respond to antidiabetic DPP4 inhibitors but others do not. An activity-based enzyme activity screening system identified gut microbial DPP4 isozymes that can decrease active GLP-1 but cannot be inhibited by sitagliptin. High-throughput screening identified Dau-d4 as a selective inhibitor of microbial DPP4 to increase GLP-1 activity and improve glucose tolerance.
Type of Medium:
Online Resource
ISSN:
0036-8075
,
1095-9203
DOI:
10.1126/science.add5787
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2023
detail.hit.zdb_id:
128410-1
detail.hit.zdb_id:
2066996-3
detail.hit.zdb_id:
2060783-0
SSG:
11
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