A Novel Camel Milk-Derived Peptide LLPK Improves Glucose-Lipid Metabolism in db/db Mice via PPAR Signaling Pathway
Abstract
1. Introduction
2. Materials and Methods
2.1. Reagents
2.2. Animals
2.3. Experimental Design
2.4. Biochemical Assays
2.5. Liver Histological Analysis
2.6. Liver Protein Preparation and Digestion
2.7. Nano-UPLC MS/MS Analysis
2.8. Data and Statistical Analysis
3. Results
3.1. The Camel Milk-Derived Peptide LLPK Effectively Ameliorated Diabetic Symptoms in db/db Mice
3.2. LLPK Improved Serum Lipid-Related Indices and DPP-4 Enzyme Activity in db/db Mice
3.3. LLPK Consumption Ameliorated Liver Damage in db/db Mice
3.4. LLPK Altered Liver Proteome Profiles in db/db Mice
3.5. LLPK Treatment Improves Lipid Metabolism in db/db Mice via PPAR Signaling Pathway
4. Discussion
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
Abbreviations
Acox1 | acyl-coenzyme A oxidase 1 |
Acaa1b | 3-ketoacyl-CoA thiolase B |
Acsl1 | long-chain-fatty-acid-CoA ligase 1 |
DPP-4 | dipeptidyl-peptidase 4 |
DCG | diabetic control group |
DEP | different expressed proteins |
Ehhadh | peroxisomal bifunctional enzyme |
FBG | fasting blood glucose |
GLP-1 | glucagon-like peptide 1 |
HPG | high-dose peptide treatment group |
ITT | insulin tolerance test |
LLPK | Leucine-Leucine-Proline-Lysine |
LPG | low-dose peptide treatment group |
NCG | normal control group |
OGTT | oral glucose tolerance tests |
PCG | metformin control group |
PCA | principal component analysis |
PPI | protein–protein Interaction |
Scd1 | acyl-CoA desaturase 1 |
Slc27a1 | long-chain fatty acid transport protein 1 |
T2DM | type 2 diabetes |
References
- Sun, H.; Saeedi, P.; Karuranga, S.; Pinkepank, M.; Ogurtsova, K.; Duncan, B.B.; Stein, C.; Basit, A.; Chan, J.C.N.; Mbanya, J.C.; et al. IDF Diabetes Atlas: Global, regional and country-level diabetes prevalence estimates for 2021 and projections for 2045. Diabetes Res. Clin. Pract. 2022, 183, 109119. [Google Scholar] [CrossRef]
- Antar, S.A.; Ashour, N.A.; Sharaky, M.; Khattab, M.; Ashour, N.A.; Zaid, R.T.; Roh, E.J.; Elkamhawy, A.; Al-Karmalawy, A.A. Diabetes mellitus: Classification, mediators, and complications; A gate to identify potential targets for the development of new effective treatments. Biomed. Pharmacother. 2023, 168, 115734. [Google Scholar] [CrossRef]
- Grossman, L.D.; Roscoe, R.; Shack, A.R. Complementary and Alternative Medicine for Diabetes. Can. J. Diabetes 2018, 42, S154–S161. [Google Scholar] [CrossRef]
- Zhang, M.; Zhu, L.; Wu, G.; Liu, T.; Qi, X.; Zhang, H. Food-derived dipeptidyl peptidase IV inhibitory peptides: Production, identification, structure-activity relationship, and their potential role in glycemic regulation. Crit. Rev. Food Sci. Nutr. 2024, 64, 2053–2075. [Google Scholar] [CrossRef]
- Koirala, P.; Dahal, M.; Rai, S.; Dhakal, M.; Nirmal, N.P.; Maqsood, S.; Al-Asmari, F.; Buranasompob, A. Dairy Milk Protein-Derived Bioactive Peptides: Avengers Against Metabolic Syndrome. Curr. Nutr. Rep. 2023, 12, 308–326. [Google Scholar] [CrossRef]
- Khalid, N.; Abdelrahim, D.N.; Hanach, N.; Alkurd, R.; Khan, M.; Mahrous, L.; Radwan, H.; Naja, F.; Madkour, M.; Obaideen, K.; et al. Effect of camel milk on lipid profile among patients with diabetes: A systematic review, meta-analysis, and meta-regression of randomized controlled trials. BMC Complement. Med. Ther. 2023, 23, 438. [Google Scholar] [CrossRef]
- Han, B.; Zhang, L.; Hou, Y.; Zhong, J.; Hettinga, K.; Zhou, P. Phosphoproteomics reveals that camel and goat milk improve glucose homeostasis in HDF/STZ-induced diabetic rats through activation of hepatic AMPK and GSK3-GYS axis. Food Res. Int. 2022, 157, 111254. [Google Scholar] [CrossRef]
- Zhang, Y.; Wang, J.; Ge, W.; Song, Y.; He, R.; Wang, Z.; Zhao, L. Camel milk peptides alleviate hyperglycemia by regulating gut microbiota and metabolites in type 2 diabetic mice. Food Res. Int. 2023, 173, 113278. [Google Scholar] [CrossRef]
- Xie, Y.; Wang, J.; Wang, S.; He, R.; Wang, Z.; Zhao, L.; Ge, W. Preparation, characterization, and mechanism of DPP-IV inhibitory peptides derived from Bactrian camel milk. Int. J. Biol. Macromol. 2024, 277, 134232. [Google Scholar] [CrossRef] [PubMed]
- Ashraf, A.; Mudgil, P.; Palakkott, A.; Iratni, R.; Gan, C.-Y.; Maqsood, S.; Ayoub, M.A. Molecular basis of the anti-diabetic properties of camel milk through profiling of its bioactive peptides on dipeptidyl peptidase IV (DPP-IV) and insulin receptor activity. J. Dairy Sci. 2021, 104, 61–77. [Google Scholar] [CrossRef] [PubMed]
- Elhadad, N.; de Campos Zani, S.C.; Chan, C.B.; Wu, J. Ovalbumin Hydrolysates Enhance Skeletal Muscle Insulin-Dependent Signaling Pathway in High-Fat Diet-Fed Mice. J. Agric. Food Chem. 2024, 72, 15248–15255. [Google Scholar] [CrossRef]
- Luo, Z.; Fu, C.; Li, T.; Gao, Q.; Miao, D.; Xu, J.; Zhao, Y. Hypoglycemic Effects of Licochalcone A on the Streptozotocin-Induced Diabetic Mice and Its Mechanism Study. J. Agric. Food Chem. 2021, 69, 2444–2456. [Google Scholar] [CrossRef]
- Wilson, M.E.; Tzeng, S.-C.; Augustin, M.M.; Meyer, M.; Jiang, X.; Choi, J.H.; Rogers, J.C.; Evans, B.S.; Kutchan, T.M.; Nusinow, D.A. Quantitative Proteomics and Phosphoproteomics Support a Role for Mut9-Like Kinases in Multiple Metabolic and Signaling Pathways in Arabidopsis. Mol. Cell. Proteom. 2021, 20, 100063. [Google Scholar] [CrossRef]
- Althnaibat, R.M.; Bruce, H.L.; Wu, J.; Gänzle, M.G. Bioactive peptides in hydrolysates of bovine and camel milk proteins: A review of studies on peptides that reduce blood pressure, improve glucose homeostasis, and inhibit pathogen adhesion. Food Res. Int. 2024, 175, 113748. [Google Scholar] [CrossRef]
- Pham, T.K.; Nguyen, T.H.T.; Yi, J.M.; Kim, G.S.; Yun, H.R.; Kim, H.K.; Won, J.C. Evogliptin, a DPP-4 inhibitor, prevents diabetic cardiomyopathy by alleviating cardiac lipotoxicity in db/db mice. Exp. Mol. Med. 2023, 55, 767–778. [Google Scholar] [CrossRef]
- Yaribeygi, H.; Atkin, S.L.; Sahebkar, A. Natural compounds with DPP-4 inhibitory effects: Implications for the treatment of diabetes. J. Cell. Biochem. 2019, 120, 10909–10913. [Google Scholar] [CrossRef]
- Drucker, D.J. Mechanisms of Action and Therapeutic Application of Glucagon-like Peptide-1. Cell Metab. 2018, 27, 740–756. [Google Scholar] [CrossRef]
- Rai, C.; Priyadarshini, P. Whey protein hydrolysates improve high-fat-diet-induced obesity by modulating the brain-peripheral axis of GLP-1 through inhibition of DPP-4 function in mice. Eur. J. Nutr. 2023, 62, 2489–2507. [Google Scholar] [CrossRef]
- Vergès, B. Pathophysiology of diabetic dyslipidaemia: Where are we? Diabetologia 2015, 58, 886–899. [Google Scholar] [CrossRef] [PubMed]
- Athyros, V.G.; Doumas, M.; Imprialos, K.P.; Stavropoulos, K.; Georgianou, E.; Katsimardou, A.; Karagiannis, A. Diabetes and lipid metabolism. Hormones 2018, 17, 61–67. [Google Scholar] [CrossRef]
- Rajman, L.; Chwalek, K.; Sinclair, D.A. Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence. Cell Metab. 2018, 27, 529–547. [Google Scholar] [CrossRef] [PubMed]
- Gross, B.; Pawlak, M.; Lefebvre, P.; Staels, B. PPARs in obesity-induced T2DM, dyslipidaemia and NAFLD. Nat. Rev. Endocrinol. 2017, 13, 36–49. [Google Scholar] [CrossRef] [PubMed]
- Tibori, K.; Orosz, G.; Zámbó, V.; Szelényi, P.; Sarnyai, F.; Tamási, V.; Rónai, Z.; Mátyási, J.; Tóth, B.; Csala, M.; et al. Molecular Mechanisms Underlying the Elevated Expression of a Potentially Type 2 Diabetes Mellitus Associated SCD1 Variant. Int. J. Mol. Sci. 2022, 23, 6221. [Google Scholar] [CrossRef]
- Görgens, S.W.; Jahn-Hofmann, K.; Bangari, D.; Cummings, S.; Metz-Weidmann, C.; Schwahn, U.; Wohlfart, P.; Schäfer, M.; Bielohuby, M. A siRNA mediated hepatic DPP-4 knockdown affects lipid, but not glucose metabolism in diabetic mice. PLoS ONE 2019, 14, e0225835. [Google Scholar] [CrossRef]
- Zou, J.; Song, Q.; Shaw, P.C.; Zuo, Z. Dendrobium officinale regulate lipid metabolism in diabetic mouse liver via PPAR-RXR signaling pathway: Evidence from an integrated multi-omics analysis. Biomed. Pharmacother. 2024, 173, 116395. [Google Scholar] [CrossRef]
- Lu, D.L.; He, A.Y.; Tan, M.; Mrad, M.; El Daibani, A.; Hu, D.H.; Liu, X.J.; Kleiboeker, B.; Che, T.; Hsu, F.F.; et al. Liver ACOX1 regulates levels of circulating lipids that promote metabolic health through adipose remodeling. Nat. Commun. 2024, 15, 4214. [Google Scholar] [CrossRef]
- Houten, S.M.; Denis, S.; Argmann, C.A.; Jia, Y.; Ferdinandusse, S.; Reddy, J.K.; Wanders, R.J.A. Peroxisomal L-bifunctional enzyme (Ehhadh) is essential for the production of medium-chain dicarboxylic acids. J. Lipid Res. 2012, 53, 1296–1303. [Google Scholar] [CrossRef]
- Dave, A.; Park, E.-J.; Kumar, A.; Parande, F.; Idle, J.R.; Pezzuto, J.M.; Beyoglu, D. Consumption of Grapes Modulates Gene Expression, Reduces Non-Alcoholic Fatty Liver Disease, and Extends Longevity in Female C57BL/6J Mice Provided with a High-Fat Western-Pattern Diet. Foods 2022, 11, 1984. [Google Scholar] [CrossRef]
- He, A.; Chen, X.; Tan, M.; Chen, Y.; Lu, D.; Zhang, X.; Dean, J.M.; Razani, B.; Lodhi, I.J. Acetyl-CoA Derived from Hepatic Peroxisomal β-Oxidation Inhibits Autophagy and Promotes Steatosis via mTORC1 Activation. Mol. Cell 2020, 79, 30–42.e34. [Google Scholar] [CrossRef]
- Wang, C.Q.; Hu, M.H.; Yi, Y.H.; Wen, X.N.; Lv, C.H.; Shi, M.; Zeng, C.X. Multiomic analysis of dark tea extract on glycolipid metabolic disorders in db/db mice. Front. Nutr. 2022, 9, 1006517. [Google Scholar] [CrossRef]
- Anderson, C.M.; Stahl, A. SLC27 fatty acid transport proteins. Mol. Asp. Med. 2013, 34, 516–528. [Google Scholar] [CrossRef] [PubMed]
- Huh, J.Y.; Reilly, S.M.; Abu-Odeh, M.; Murphy, A.N.; Mahata, S.K.; Zhang, J.Y.; Cho, Y.; Seo, J.B.; Hung, C.W.; Green, C.R.; et al. TANK-Binding Kinase 1 Regulates the Localization of Acyl-CoA Synthetase ACSL1 to Control Hepatic Fatty Acid Oxidation. Cell Metab. 2020, 32, 1012–1027.e7. [Google Scholar] [CrossRef] [PubMed]
- Pfohl, M.; DaSilva, N.A.; Marques, E.; Agudelo, J.; Liu, C.; Goedken, M.; Slitt, A.L.; Seeram, N.P.; Ma, H. Hepatoprotective and anti-inflammatory effects of a standardized pomegranate (Punica granatum) fruit extract in high fat diet-induced obese C57BL/6 mice. Int. J. Food Sci. Nutr. 2021, 72, 499–510. [Google Scholar] [CrossRef] [PubMed]
NCG | DCG | PCG | LPG | HPG | |
---|---|---|---|---|---|
TC (mmol/L) | 6.72 ± 0.16 a | 15.63 ± 0.81 d | 7.63 ± 0.57 b | 9.77 ± 1.00 c | 10.53 ± 1.09 c |
TG (mmol/L) | 5.14 ± 0.39 b | 7.5 ± 0.36 d | 5.51 ± 0.22 c | 5.44 ± 0.3 bc | 4.79 ± 0.19 a |
HDL-C (mmol/L) | 3.17 ± 0.45 c | 1.44 ± 0.32 a | 2.82 ± 0.91 c | 1.78 ± 0.68 b | 1.26 ± 0.53 b |
LDL-C (mmol/L) | 3.40 ± 0.43 a | 12.89 ± 0.65 d | 4.96 ± 0.79 b | 7.53 ± 1.06 c | 7.72 ± 1.13 c |
Insulin (mIU/L) | 8.35 ± 0.24 c | 9.96 ± 0.29 d | 7.63 ± 0.47 ab | 7.75 ± 0.45 ab | 7.93 ± 0.23 b |
HOMA-IR | 2.44 ± 0.27 a | 11.64 ± 0.48 d | 3.53 ± 0.77 b | 6.5 ± 1.39 c | 4.29 ± 1.38 b |
HOMA-IS | 0.0192 ± 0.0016 d | 0.0038 ± 0.0001 a | 0.0142 ± 0.0022 c | 0.0085 ± 0.0010 b | 0.0112 ± 0.0031 bc |
GLP-1 (pmol/L) | 0.87 ± 0.04 bc | 0.80 ± 0.03 a | 1.10 ± 0.07 d | 0.83 ± 0.05 ab | 0.90 ± 0.06 c |
DPP-4 activity (mU/mL) | 5.72 ± 0.46 a | 29.95 ± 0.93 d | 6.45 ± 0.35 a | 23.33 ± 1.82 c | 13.51 ± 0.33 b |
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Han, B.; Ye, Y.; Zhang, C.; Zhang, L.; Zhou, P. A Novel Camel Milk-Derived Peptide LLPK Improves Glucose-Lipid Metabolism in db/db Mice via PPAR Signaling Pathway. Nutrients 2025, 17, 1693. https://doi.org/10.3390/nu17101693
Han B, Ye Y, Zhang C, Zhang L, Zhou P. A Novel Camel Milk-Derived Peptide LLPK Improves Glucose-Lipid Metabolism in db/db Mice via PPAR Signaling Pathway. Nutrients. 2025; 17(10):1693. https://doi.org/10.3390/nu17101693
Chicago/Turabian StyleHan, Binsong, Yuhui Ye, Cunzheng Zhang, Lina Zhang, and Peng Zhou. 2025. "A Novel Camel Milk-Derived Peptide LLPK Improves Glucose-Lipid Metabolism in db/db Mice via PPAR Signaling Pathway" Nutrients 17, no. 10: 1693. https://doi.org/10.3390/nu17101693
APA StyleHan, B., Ye, Y., Zhang, C., Zhang, L., & Zhou, P. (2025). A Novel Camel Milk-Derived Peptide LLPK Improves Glucose-Lipid Metabolism in db/db Mice via PPAR Signaling Pathway. Nutrients, 17(10), 1693. https://doi.org/10.3390/nu17101693