Activation of GPR120 involved in the anti-inflammatory response and alleviation of apoptosis in sepsis-associated acute kidney injury

Activation of GPR120 involved in the anti-inflammatory response and alleviation of apoptosis in sepsis-associated acute kidney injury | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Activation of GPR120 involved in the anti-inflammatory response and alleviation of apoptosis in sepsis-associated acute kidney injury Deyuan Zhi, Xi Wu, Mingyuan Liu, Hao Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6225887/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Current treatments for sepsis-associated acute kidney injury (S-AKI) lack specificity and urgently need novel therapeutic targets. G-protein-coupled receptor 120 (GPR120) has exerted anti-inflammatory and anti-apoptotic effects across multiple cells, however, the specific role of GPR120 in the pathogenesis of S-AKI has not been thoroughly investigated. Materials and Methods S-AKI models were established in wild-type (WT) and Gpr120 −/− mice via lipopolysaccharide (LPS) injection. Mice were orally pretreated with docosahexaenoic acid (DHA) for 14 days before LPS injection. Eighteen hours after LPS administration, renal function, inflammatory markers, and apoptosis were assessed through biochemical assays, histological analysis, and western blotting. Results LPS exposure significantly decreased survival rates and elevated serum creatinine and blood urea nitrogen (BUN) levels in S-AKI mice. DHA pretreatment ameliorated these effects by activating GPR120. This activation also reduced the expression of IL-6, TNF-α, and IL-1β at both the gene and protein levels, accompanied by decreased phosphorylation of NF-κB and JNK signaling pathways. Furthermore, GPR120 activation diminished the number of TUNEL-positive cells and cleaved caspase-3 in renal tissues. In contrast, Gpr120 −/− mice exhibited aggravated renal dysfunction, inflammation, and apoptosis following LPS challenge. Conclusions Activation of GPR120 by DHA alleviates inflammation and apoptosis, underscoring its novel therapeutic potential for S-AKI. Health sciences/Nephrology/Kidney diseases Health sciences/Diseases/Kidney diseases Sepsis acute kidney injury G-protein-coupled receptor 120 inflammation apoptosis Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Sepsis is a life-threatening syndrome characterized by severe organ dysfunction resulting from a dysregulated host immune response to infection[ 1 ]. Among its complications, sepsis-associated acute kidney injury (S-AKI) is a prevalent and serious condition, contributing significantly to the high mortality rate observed in septic patients[ 2 , 3 ]. Lipopolysaccharides (LPS), key components of the cell walls of Gram-negative bacteria, play a critical role in sepsis pathogenesis[ 4 ]. LPS interacts with Toll-like receptor 4 (TLR4) on macrophages, initiating the activation of pro-inflammatory signaling pathways, such as NF-κB and JNK, and triggering the release of cytokines like interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β)[ 5 ]. These cytokines are pivotal in mediating the inflammatory cascade that characterizes sepsis[ 6 ]. The pathophysiological mechanisms underlying S-AKI are multifactorial, involving systemic and renal inflammation, microcirculatory dysfunction, apoptosis, and metabolic reprogramming[ 7 , 8 ]. Despite advancements in critical care, the lack of targeted therapies for S-AKI highlights a pressing need for novel therapeutic strategies. G-protein-coupled receptor 120 (GPR120), also known as free fatty acid receptor 4 (FFAR4), is a receptor for long-chain free fatty acids such as docosahexaenoic acid (DHA)[ 9 ]. This receptor is recognized for modulating various physiological functions, including taste perception and adipogenesis[ 10 , 11 ]. Moreover, prior studies have demonstrated that GPR120 activation exerts anti-inflammatory and anti-apoptotic effects across multiple cell types[ 9 , 12 – 15 ]. However, the specific role of GPR120 in the pathogenesis of S-AKI has not been thoroughly investigated. This study explores the therapeutic potential of GPR120 activation in an S-AKI mouse model. We hypothesize that DHA, as a GPR120 agonist, mitigates kidney injury by reducing inflammation, downregulating inflammatory cytokines, and attenuating apoptosis of renal tubular epithelial cells. Methods Male C57BL/6 wild-type (WT, purchased from Charles River Laboratories) and Gpr120 knockout ( Gpr120 −/− , purchased from cyagen) mice aged 8–10 weeks (weighing 20–25 g) were used to establish S-AKI models. S-AKI was induced by intraperitoneal injection of LPS (10 mg/kg). Mice were randomly assigned to five experimental groups (n = 10 per group): Control group: Received saline injection. LPS group: Received LPS injection. LPS + DHA group: Pre-treated with DHA (1 g/kg/day, oral gavage) for 14 days prior to LPS injection. Gpr120 −/− +LPS group: Gpr120 −/− mice received LPS injection. Gpr120 −/− +LPS + DHA group: Gpr120 −/− mice were pre-treated with DHA before LPS injection. Eighteen hours post-LPS injection, all mice were euthanized by inhaling excessive isoflurane in accordance with the 2020 AVMA Animal Euthanasia Guidelines for sample collection[ 16 ]. Serum creatinine and BUN levels were measured to assess renal function. Inflammatory cytokines (IL-6, TNF-α, IL-1β) were quantified using ELISA kits. Histological examination, including hematoxylin and eosin (H&E) staining and TUNEL assay, was performed to evaluate renal injury and apoptosis. Western blotting was used to measure the phosphorylation of NF-κB and JNK pathways as well as the expression of cleaved caspase-3. The laboratory animal management and use committee of Beijing Friendship Hospital, Capital Medical University has approved all animal experiments [20-2007]. All experimental procedures follow internationally recognized principles and guidelines, and the study is reported in accordance with ARRIVE guidelines ( https://arriveguidelines.org ). Statistical Analysis The normality distribution of all variables was tested by the Shapiro-Wilk test. Normally distributed continuous variables were reported as mean ± standard deviation (SD). Categorical variables were represented as frequencies and percentages. The differences in continuous variables between the two groups were tested by Student’s t test or Mann-Whitney U test. Expression levels of different proteins were graphed by bar plot. The Kaplan-Meier survival analysis was employed to compare the effects of different treatment factors on the survival rate. All reported P-values were two-tailed, and P < 0.05 was considered statistically significant. Results Effect of GPR120 Activation on Survival and Renal Function After injecting LPS to construct the S-AKI mice model, the survival rate of the mice decreased compared to the control group. GPR agonist DHA pretreatment improved survival in LPS-treated mice (, p < 0.01) (Fig. 1 A). Biochemical analysis revealed that LPS markedly increased serum creatinine, BUN levels, and kidney injury marker KIM-1 ( p < 0.001), which were significantly attenuated by DHA pretreatment ( p < 0.05) (Figs. 1 B-D). Inflammatory Response Modulation by GPR120 LPS exposure upregulated renal expression of inflammatory cytokines IL-6, TNF-α, and IL-1β at both gene and protein levels ( p < 0.01). DHA pretreatment reduced these markers significantly ( p < 0.01) (Figs. 1 E-G). Western blot analysis showed that LPS-induced phosphorylation of NF-κB and JNK pathways was suppressed following DHA treatment ( p < 0.05) (Figs. 1 H-I). Apoptosis Inhibition via GPR120 Activation TUNEL staining and cleaved caspase-3 immunohistochemistry revealed that LPS significantly increased apoptosis in renal tissues. DHA pretreatment effectively reduced the number of TUNEL-positive cells and cleaved caspase-3 levels (Figs. 2 A-B). Impact of Gpr120 Deficiency on S-AKI Survival analysis showed no significant differences or trends in survival rates between Gpr120 −/− mice and WT mice ( p > 0.05). Biochemical analysis showed that after LPS injection, the serum creatinine and BUN levels of Gpr120 −/− mice were significantly higher than those of WT mice ( p < 0.05) (Figs. 3 A). Similarly, the kidney injury marker KIM-1 in gene and protein levels of Gpr120 −/− mice were higher than those of WT mice ( p 0.05) (Figs. 3 D). However, IL-6 in gene level, TNF - α, and IL-1 β in gene and protein levels were significantly elevated compared to WT mice ( p < 0.05) (Figs. 3 E-F). Western blot analysis revealed the phosphorylation levels of NF - κ B and JNK pathways in Gpr120 −/− mice were significantly higher than those in WT mice (Figs. 3 G-H). In Gpr120 −/− mice, pretreatment with DHA still partially reduced renal injury, inflammatory cytokine levels, and phosphorylation of NF - κ B and JNK pathways induced by LPS injection (Figs. 3 A-H). TUNEL staining and cleaved caspase-3 immunohistochemistry showed more severe apoptosis in Gpr120 −/− mice than WT mice (Figs. 4 A-B). Discussion This study provides compelling evidence that GPR120 activation by DHA can mitigate S-AKI through dual mechanisms: inhibition of inflammation and reduction of renal tubular epithelial cell apoptosis. These findings underscore the potential of GPR120 as a novel therapeutic target for S-AKI management. Our results align with prior studies demonstrating the anti-inflammatory properties of GPR120 activation in other disease models[ 17 – 19 ]. Specifically, DHA treatment significantly decreased the expression of key pro-inflammatory cytokines, including IL-6, TNF–α, and IL-1β, in the kidney tissues of septic mice. This anti-inflammatory effect was accompanied by the suppression of NF-κB and JNK signaling pathways, both of which play pivotal roles in the inflammatory cascade during sepsis[ 20 ]. These findings suggest that GPR120 activation not only reduces cytokine production but also modulates upstream signaling mechanisms critical for sepsis-induced inflammation. In addition to its anti-inflammatory effects, GPR120 activation markedly reduced apoptosis, as evidenced by a lower number of TUNEL-positive cells and decreased levels of cleaved caspase-3 in renal tissues. Given that excessive apoptosis is a hallmark of AKI and a key driver of kidney dysfunction, these results highlight the dual role of GPR120 in protecting against both inflammatory damage and apoptosis[ 21 – 23 ]. The observed anti-apoptotic effects are likely mediated by the inhibition of inflammatory signaling, further supporting the interdependence of these pathological processes in AKI[ 23 ]. The findings from Gpr120 −/− mice further solidify the role of GPR120 in renal protection. The exacerbation of inflammation, apoptosis, and kidney dysfunction in Gpr120 deficiency mice underscores the critical importance of endogenous GPR120 activation in mitigating S-AKI. It has been reported that long-chain fatty acids, including DHA, can activate not only GPR120 but also GPR40 expressed in the kidneys and decrease renal inflammation[ 13 ]. This can explain why we observed that DHA still reduced the inflammatory levels and apoptosis in Gpr120 −/− mice. However, the expression of GPR40 in the kidneys is much lower than GPR120[ 13 ]. A study has shown that agonist GW9508 and inhibitor GW1100 of GPR40 were ineffective against neuroinflammation and apoptosis[ 24 ]. So we considered that DHA mainly exerts anti-inflammatory and anti-apoptotic effects in S-AKI mice through GPR120. This study also opens avenues for further research. Future investigations should aim to elucidate the downstream signaling pathways of GPR120 activation, particularly exploring whether pathways such as PI3K/Akt contribute to its anti-apoptotic effects in S-AKI mice. Additionally, long-term studies are needed to evaluate the sustained efficacy and safety of GPR120 agonists in chronic or recurring AKI models. Validation in humanized models or clinical trials will be critical for translating these findings into therapeutic strategies. Conclusion This study demonstrates that activation of GPR120 by DHA alleviates sepsis-associated acute kidney injury (S-AKI) through the inhibition of inflammation and reduction of renal tubular epithelial cell apoptosis. These findings highlight GPR120 as a potential therapeutic target for S-AKI. Future research should further explore the downstream signaling pathways of GPR120 activation and assess the efficacy and safety of GPR120 agonists in clinical applications. Declarations Funding This work was supported by Beijing Tongzhou District Economic and Information Technology Bureau's Pharmaceutical and Health Industry Development Project [JX2023YJ020], Science and Technology Program of Beijing Tongzhou District [KJ2023CX012] and Young Elite Scientist Sponsorship Program By BAST [No.BYESS2024045]. Conflict of Interest Statement The authors have no relevant financial or non-financial interests to disclose. Data Availability All data are available from the manuscript and supplementary materials. Author Contributions Xi Wu and Deyuan Zhi conceived and designed this study. Xi Wu and Mingyuan Liu conducted experiments, wrote and revised the manuscript. Hao Wang analyzed the statistical data. All authors have read and approved the final manuscript. References Balkrishna, A. et al. Sepsis-mediated renal dysfunction: Pathophysiology, biomarkers and role of phytoconstituents in its management. Biomed. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6225887","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":451350748,"identity":"43584532-ab35-447b-a54d-b6f9df1976be","order_by":0,"name":"Deyuan Zhi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYDACCcYGCTCDvQEqcoBoLTwwpYS1gBGIkUCkFvnZzY03PrYdljeXfPzw0802Bjm+GwmMnwvwaGGcc7DZcmbbYcOds9OMpXPbGIwlbyQwS8/Ao4VZIrFNmrftMOOG2zlszEAtiRtuJLAx8+DRwgbS8rftsP2Gm2fAWuoJauEBaWFsOww0nAesJcGAkBYJicRmy55z6ckbzgD9knNOwnDmmYfN0vi0yM9If3jjR5m17Ybjhx9+zimzkec7nnzwMz4tYMDIhrAVxG0gpAEI/hChZhSMglEwCkYuAACo3ExB0C8O7wAAAABJRU5ErkJggg==","orcid":"","institution":"Capital Medical University Affiliated Beijing Friendship Hospital","correspondingAuthor":true,"prefix":"","firstName":"Deyuan","middleName":"","lastName":"Zhi","suffix":""},{"id":451350749,"identity":"9bcff86f-ef72-4cb2-9f26-cc7a68604dd8","order_by":1,"name":"Xi Wu","email":"","orcid":"","institution":"Capital Medical University Affiliated Beijing Friendship Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xi","middleName":"","lastName":"Wu","suffix":""},{"id":451350753,"identity":"d8258377-c782-4766-bfaa-389388e969a5","order_by":2,"name":"Mingyuan Liu","email":"","orcid":"","institution":"Capital Medical University Affiliated Beijing Friendship Hospital","correspondingAuthor":false,"prefix":"","firstName":"Mingyuan","middleName":"","lastName":"Liu","suffix":""},{"id":451350755,"identity":"054779b5-054c-4439-a3b3-6915cdacd9b0","order_by":3,"name":"Hao Wang","email":"","orcid":"","institution":"Capital Medical University Affiliated Beijing Friendship Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-03-14 11:38:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6225887/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6225887/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":82102313,"identity":"724135b5-c752-4994-a595-40c8a2b1c407","added_by":"auto","created_at":"2025-05-06 19:11:07","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":447918,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDHA treatment reduces LPS-induced renal damage and inflammatory response A \u003c/strong\u003eThe survival curve of control group, LPS group, and LPS+DHA group.\u003cstrong\u003e B\u003c/strong\u003e ELISA kit analysis of blood urea nitrogen (BUN) and creatinine (Cr) levels in each group. \u003cstrong\u003eC\u003c/strong\u003e The protein and mRNA \u003cstrong\u003e(D) \u003c/strong\u003elevels of Kidney injury mediator-1 (KIM-1) in each group. \u003cstrong\u003eE \u003c/strong\u003eELISA of protein levels of IL-6, TNF-α, and IL-1β (\u003cstrong\u003eF\u003c/strong\u003e) in each group. \u003cstrong\u003eG\u003c/strong\u003e qPCR of IL-6, TNF-α, and IL-1β mRNA levels in each group. \u003cstrong\u003eH, I\u003c/strong\u003e The immunoblotting analysis of the activities of NF-κB and JNK in each group. The differences in categorical variables between the two groups were tested by the chi-square test or Fisher’s exact test and represented as frequencies and percentages. The differences in continuous variables between the two groups were tested by Student’s t test or Mann-Whitney U test and reported as mean ± standard deviation (SD). The figure was created by GraghPad Prism. Expression levels of different proteins were graphed by bar plot. *\u003cem\u003ep\u003c/em\u003e\u0026lt; 0.05; **\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01; ***\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; n.s. \u003cem\u003ep\u003c/em\u003e \u0026gt; 0.05.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/b30451c416677d6981a732af.png"},{"id":82102311,"identity":"468922a8-6170-487e-b44f-9e9d75fd8c3b","added_by":"auto","created_at":"2025-05-06 19:11:07","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":598317,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDHA treatment alleviates LPS-induced apoptosis of renal tubular epithelial cells A \u003c/strong\u003eThe TUNEL staining of apoptosis in control group, LPS group, and LPS+DHA group. \u003cstrong\u003eB\u003c/strong\u003e The Caspase 3 immunohistochemistry of apoptosis in each group.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/40c0aeaa60425e2449deb862.png"},{"id":82102317,"identity":"8a4a438f-d4be-4815-b7c8-b3563f14a450","added_by":"auto","created_at":"2025-05-06 19:11:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":643670,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003e\u003cstrong\u003eGpr120\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e deficiency exacerbates LPS-induced inflammatory response\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eA \u003c/strong\u003eELISA kit analysis of blood urea nitrogen (BUN) and creatinine (Cr) levels in WT+LPS group, WT+LPS+DHA group, \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e-/-\u003c/em\u003e\u003c/sup\u003e+LPS group, and \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e-/-\u003c/em\u003e\u003c/sup\u003e+LPS+DHA group. \u003cstrong\u003eB\u003c/strong\u003e The protein and mRNA \u003cstrong\u003e(C) \u003c/strong\u003elevels of Kidney incury mediator-1 (KIM-1) in each group. \u003cstrong\u003eD \u003c/strong\u003eELISA of protein levels of IL-6, TNF-α, and IL-1β (\u003cstrong\u003eE\u003c/strong\u003e) in each group. \u003cstrong\u003eF\u003c/strong\u003e qPCR of mRNA levels of IL-6, TNF-α, and IL-1β in each group. \u003cstrong\u003eG, H\u003c/strong\u003e The immunoblotting analysis of the activities of NF-κB and JNK in each group. The differences in categorical variables between the two groups were tested by the chi-square test or Fisher’s exact test and represented as frequencies and percentages. The differences in continuous variables between the two groups were tested by Student’s t test or Mann-Whitney U test and reported as mean ± standard deviation (SD). The figure was created by GraghPad Prism. Expression levels of different proteins were graphed by bar plot. *\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05; **\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.01; ***\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; n.s. \u003cem\u003ep\u003c/em\u003e \u0026gt; 0.05.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/c5eb2afbe4290874985b419b.png"},{"id":82102315,"identity":"99c6edf1-031b-434b-8135-7b2463a9f570","added_by":"auto","created_at":"2025-05-06 19:11:07","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":500285,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDHA treatment alleviates LPS-induced apoptosis of renal tubular epithelial cells A \u003c/strong\u003eThe TUNEL staining of apoptosis in WT+LPS group, WT+DHA+LPS group, \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e-/-\u003c/em\u003e\u003c/sup\u003e+LPS group, and \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e-/-\u003c/em\u003e\u003c/sup\u003e+LPS+DHA group. \u003cstrong\u003eB\u003c/strong\u003e The Caspase 3 immunohistochemistry of apoptosis in each group.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/91fcab1b7de38185412bc6a9.png"},{"id":82753271,"identity":"15421861-1789-493a-b266-a1d16bc04b98","added_by":"auto","created_at":"2025-05-14 23:01:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2857931,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/9b7783fe-23e1-423f-9155-0fa3c9e13a63.pdf"},{"id":82102330,"identity":"f280393d-7e9e-46ba-b5e0-c943b8781cc5","added_by":"auto","created_at":"2025-05-06 19:11:10","extension":"zip","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":31431254,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterial.zip","url":"https://assets-eu.researchsquare.com/files/rs-6225887/v1/e0af2bfa8b287261f903f05f.zip"}],"financialInterests":"No competing interests reported.","formattedTitle":"Activation of GPR120 involved in the anti-inflammatory response and alleviation of apoptosis in sepsis-associated acute kidney injury","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSepsis is a life-threatening syndrome characterized by severe organ dysfunction resulting from a dysregulated host immune response to infection[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Among its complications, sepsis-associated acute kidney injury (S-AKI) is a prevalent and serious condition, contributing significantly to the high mortality rate observed in septic patients[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Lipopolysaccharides (LPS), key components of the cell walls of Gram-negative bacteria, play a critical role in sepsis pathogenesis[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. LPS interacts with Toll-like receptor 4 (TLR4) on macrophages, initiating the activation of pro-inflammatory signaling pathways, such as NF-κB and JNK, and triggering the release of cytokines like interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1β)[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These cytokines are pivotal in mediating the inflammatory cascade that characterizes sepsis[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe pathophysiological mechanisms underlying S-AKI are multifactorial, involving systemic and renal inflammation, microcirculatory dysfunction, apoptosis, and metabolic reprogramming[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Despite advancements in critical care, the lack of targeted therapies for S-AKI highlights a pressing need for novel therapeutic strategies.\u003c/p\u003e \u003cp\u003eG-protein-coupled receptor 120 (GPR120), also known as free fatty acid receptor 4 (FFAR4), is a receptor for long-chain free fatty acids such as docosahexaenoic acid (DHA)[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This receptor is recognized for modulating various physiological functions, including taste perception and adipogenesis[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Moreover, prior studies have demonstrated that GPR120 activation exerts anti-inflammatory and anti-apoptotic effects across multiple cell types[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, the specific role of GPR120 in the pathogenesis of S-AKI has not been thoroughly investigated.\u003c/p\u003e \u003cp\u003eThis study explores the therapeutic potential of GPR120 activation in an S-AKI mouse model. We hypothesize that DHA, as a GPR120 agonist, mitigates kidney injury by reducing inflammation, downregulating inflammatory cytokines, and attenuating apoptosis of renal tubular epithelial cells.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eMale C57BL/6 wild-type (WT, purchased from Charles River Laboratories) and \u003cem\u003eGpr120\u003c/em\u003e knockout (\u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e, purchased from cyagen) mice aged 8\u0026ndash;10 weeks (weighing 20\u0026ndash;25 g) were used to establish S-AKI models. S-AKI was induced by intraperitoneal injection of LPS (10 mg/kg). Mice were randomly assigned to five experimental groups (n\u0026thinsp;=\u0026thinsp;10 per group):\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eControl group: Received saline injection.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eLPS group: Received LPS injection.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eLPS\u0026thinsp;+\u0026thinsp;DHA group: Pre-treated with DHA (1 g/kg/day, oral gavage) for 14 days prior to LPS injection.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e\u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e+LPS group: \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice received LPS injection.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003e\u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e+LPS\u0026thinsp;+\u0026thinsp;DHA group: \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice were pre-treated with DHA before LPS injection.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eEighteen hours post-LPS injection, all mice were euthanized by inhaling excessive isoflurane in accordance with the 2020 AVMA Animal Euthanasia Guidelines for sample collection[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Serum creatinine and BUN levels were measured to assess renal function. Inflammatory cytokines (IL-6, TNF-α, IL-1β) were quantified using ELISA kits. Histological examination, including hematoxylin and eosin (H\u0026amp;E) staining and TUNEL assay, was performed to evaluate renal injury and apoptosis. Western blotting was used to measure the phosphorylation of NF-κB and JNK pathways as well as the expression of cleaved caspase-3. The laboratory animal management and use committee of Beijing Friendship Hospital, Capital Medical University has approved all animal experiments [20-2007]. All experimental procedures follow internationally recognized principles and guidelines, and the study is reported in accordance with ARRIVE guidelines (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://arriveguidelines.org\u003c/span\u003e\u003cspan address=\"https://arriveguidelines.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eThe normality distribution of all variables was tested by the Shapiro-Wilk test. Normally distributed continuous variables were reported as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD). Categorical variables were represented as frequencies and percentages. The differences in continuous variables between the two groups were tested by Student\u0026rsquo;s t test or Mann-Whitney U test. Expression levels of different proteins were graphed by bar plot. The Kaplan-Meier survival analysis was employed to compare the effects of different treatment factors on the survival rate. All reported P-values were two-tailed, and P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eEffect of GPR120 Activation on Survival and Renal Function\u003c/h2\u003e \u003cp\u003eAfter injecting LPS to construct the S-AKI mice model, the survival rate of the mice decreased compared to the control group. GPR agonist DHA pretreatment improved survival in LPS-treated mice (, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA). Biochemical analysis revealed that LPS markedly increased serum creatinine, BUN levels, and kidney injury marker KIM-1 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), which were significantly attenuated by DHA pretreatment (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB-D).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eInflammatory Response Modulation by GPR120\u003c/h3\u003e\n\u003cp\u003eLPS exposure upregulated renal expression of inflammatory cytokines IL-6, TNF-α, and IL-1β at both gene and protein levels (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). DHA pretreatment reduced these markers significantly (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01) (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE-G). Western blot analysis showed that LPS-induced phosphorylation of NF-κB and JNK pathways was suppressed following DHA treatment (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eH-I).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eApoptosis Inhibition via GPR120 Activation\u003c/h3\u003e\n\u003cp\u003eTUNEL staining and cleaved caspase-3 immunohistochemistry revealed that LPS significantly increased apoptosis in renal tissues. DHA pretreatment effectively reduced the number of TUNEL-positive cells and cleaved caspase-3 levels (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA-B).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eImpact of\u003c/b\u003e \u003cb\u003eGpr120\u003c/b\u003e \u003cb\u003eDeficiency on S-AKI\u003c/b\u003e\u003c/p\u003e \u003cp\u003eSurvival analysis showed no significant differences or trends in survival rates between \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice and WT mice (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Biochemical analysis showed that after LPS injection, the serum creatinine and BUN levels of \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice were significantly higher than those of WT mice (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). Similarly, the kidney injury marker KIM-1 in gene and protein levels of \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice were higher than those of WT mice (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB-C). After LPS injection, the inflammatory cytokine IL-6 of \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice did not show statistical differences in protein level compared to WT mice (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD). However, IL-6 in gene level, TNF - α, and IL-1 β in gene and protein levels were significantly elevated compared to WT mice (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eE-F). Western blot analysis revealed the phosphorylation levels of NF - κ B and JNK pathways in \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice were significantly higher than those in WT mice (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eG-H). In \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice, pretreatment with DHA still partially reduced renal injury, inflammatory cytokine levels, and phosphorylation of NF - κ B and JNK pathways induced by LPS injection (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA-H). TUNEL staining and cleaved caspase-3 immunohistochemistry showed more severe apoptosis in \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice than WT mice (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA-B).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study provides compelling evidence that GPR120 activation by DHA can mitigate S-AKI through dual mechanisms: inhibition of inflammation and reduction of renal tubular epithelial cell apoptosis. These findings underscore the potential of GPR120 as a novel therapeutic target for S-AKI management.\u003c/p\u003e \u003cp\u003eOur results align with prior studies demonstrating the anti-inflammatory properties of GPR120 activation in other disease models[\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Specifically, DHA treatment significantly decreased the expression of key pro-inflammatory cytokines, including IL-6, TNF\u0026ndash;α, and IL-1β, in the kidney tissues of septic mice. This anti-inflammatory effect was accompanied by the suppression of NF-κB and JNK signaling pathways, both of which play pivotal roles in the inflammatory cascade during sepsis[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. These findings suggest that GPR120 activation not only reduces cytokine production but also modulates upstream signaling mechanisms critical for sepsis-induced inflammation.\u003c/p\u003e \u003cp\u003eIn addition to its anti-inflammatory effects, GPR120 activation markedly reduced apoptosis, as evidenced by a lower number of TUNEL-positive cells and decreased levels of cleaved caspase-3 in renal tissues. Given that excessive apoptosis is a hallmark of AKI and a key driver of kidney dysfunction, these results highlight the dual role of GPR120 in protecting against both inflammatory damage and apoptosis[\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The observed anti-apoptotic effects are likely mediated by the inhibition of inflammatory signaling, further supporting the interdependence of these pathological processes in AKI[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe findings from \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice further solidify the role of GPR120 in renal protection. The exacerbation of inflammation, apoptosis, and kidney dysfunction in \u003cem\u003eGpr120\u003c/em\u003e deficiency mice underscores the critical importance of endogenous GPR120 activation in mitigating S-AKI.\u003c/p\u003e \u003cp\u003eIt has been reported that long-chain fatty acids, including DHA, can activate not only GPR120 but also GPR40 expressed in the kidneys and decrease renal inflammation[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. This can explain why we observed that DHA still reduced the inflammatory levels and apoptosis in \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice. However, the expression of GPR40 in the kidneys is much lower than GPR120[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. A study has shown that agonist GW9508 and inhibitor GW1100 of GPR40 were ineffective against neuroinflammation and apoptosis[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. So we considered that DHA mainly exerts anti-inflammatory and anti-apoptotic effects in S-AKI mice through GPR120.\u003c/p\u003e \u003cp\u003eThis study also opens avenues for further research. Future investigations should aim to elucidate the downstream signaling pathways of GPR120 activation, particularly exploring whether pathways such as PI3K/Akt contribute to its anti-apoptotic effects in S-AKI mice. Additionally, long-term studies are needed to evaluate the sustained efficacy and safety of GPR120 agonists in chronic or recurring AKI models. Validation in humanized models or clinical trials will be critical for translating these findings into therapeutic strategies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study demonstrates that activation of GPR120 by DHA alleviates sepsis-associated acute kidney injury (S-AKI) through the inhibition of inflammation and reduction of renal tubular epithelial cell apoptosis. These findings highlight GPR120 as a potential therapeutic target for S-AKI. Future research should further explore the downstream signaling pathways of GPR120 activation and assess the efficacy and safety of GPR120 agonists in clinical applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Beijing Tongzhou District Economic and Information Technology Bureau\u0026apos;s Pharmaceutical and Health Industry Development Project [JX2023YJ020], Science and Technology Program of Beijing Tongzhou District [KJ2023CX012] and Young Elite Scientist Sponsorship Program By BAST [No.BYESS2024045].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no\u0026nbsp;relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data are available\u0026nbsp;from the manuscript and supplementary materials.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eXi Wu and Deyuan Zhi conceived and designed this study. Xi Wu and Mingyuan\u0026nbsp;Liu conducted experiments, wrote and revised the manuscript. Hao Wang analyzed the statistical data. All authors have read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBalkrishna, A. et al. Sepsis-mediated renal dysfunction: Pathophysiology, biomarkers and role of phytoconstituents in its management. \u003cem\u003eBiomed. Pharmacotherapy = Biomedecine Pharmacotherapie\u003c/em\u003e. \u003cb\u003e165\u003c/b\u003e, 115183. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.biopha.2023.115183\u003c/span\u003e\u003cspan address=\"10.1016/j.biopha.2023.115183\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2023). 37487442. PubMed.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePoston, J. T. \u0026amp; Jay, L. 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PubMed.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Sepsis, acute kidney injury, G-protein-coupled receptor 120, inflammation, apoptosis","lastPublishedDoi":"10.21203/rs.3.rs-6225887/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6225887/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eCurrent treatments for sepsis-associated acute kidney injury (S-AKI) lack specificity and urgently need novel therapeutic targets. G-protein-coupled receptor 120 (GPR120) has exerted anti-inflammatory and anti-apoptotic effects across multiple cells, however, the specific role of GPR120 in the pathogenesis of S-AKI has not been thoroughly investigated.\u003c/p\u003e\u003ch2\u003eMaterials and Methods\u003c/h2\u003e \u003cp\u003eS-AKI models were established in wild-type (WT) and \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice via lipopolysaccharide (LPS) injection. Mice were orally pretreated with docosahexaenoic acid (DHA) for 14 days before LPS injection. Eighteen hours after LPS administration, renal function, inflammatory markers, and apoptosis were assessed through biochemical assays, histological analysis, and western blotting.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eLPS exposure significantly decreased survival rates and elevated serum creatinine and blood urea nitrogen (BUN) levels in S-AKI mice. DHA pretreatment ameliorated these effects by activating GPR120. This activation also reduced the expression of IL-6, TNF-α, and IL-1β at both the gene and protein levels, accompanied by decreased phosphorylation of NF-κB and JNK signaling pathways. Furthermore, GPR120 activation diminished the number of TUNEL-positive cells and cleaved caspase-3 in renal tissues. In contrast, \u003cem\u003eGpr120\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;/\u0026minus;\u003c/em\u003e\u003c/sup\u003e mice exhibited aggravated renal dysfunction, inflammation, and apoptosis following LPS challenge.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eActivation of GPR120 by DHA alleviates inflammation and apoptosis, underscoring its novel therapeutic potential for S-AKI.\u003c/p\u003e","manuscriptTitle":"Activation of GPR120 involved in the anti-inflammatory response and alleviation of apoptosis in sepsis-associated acute kidney injury","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-06 19:11:03","doi":"10.21203/rs.3.rs-6225887/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"06070cc7-f310-413f-8824-cc18856daaa1","owner":[],"postedDate":"May 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":48019678,"name":"Health sciences/Nephrology/Kidney diseases"},{"id":48019679,"name":"Health sciences/Diseases/Kidney diseases"}],"tags":[],"updatedAt":"2025-05-14T22:53:22+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-06 19:11:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6225887","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6225887","identity":"rs-6225887","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}