Association of GAS6, AXL, and GAS6-AS lncRNAs with nephropathy in Egyptian patients with type 2 diabetes mellitus: a case–control observational study

Nutrition & Diabetes ARTICLE www.nature.com/nutd OPEN Association of GAS6, AXL, and GAS6-AS lncRNAs with nephropathy in Egyptian patients with type 2 diabetes mellitus: a case–control observational study Tarek Kamal Motawi 1✉ , Dina Sabry2,3, Nancy Mamdouh Ahmed 1,4 and Nancy Nabil Shahin 1,4 ✉ 1234567890();,: © The Author(s) 2025 BACKGROUND/OBJECTIVES: Diabetic nephropathy (DN) is a prevalent microvascular diabetic complication that is not totally unveiled. In this study, we considered GAS6, AXL, GAS6-AS1, and GAS6-DT as possible early diagnostic biomarkers of DN. SUBJECTS/METHODS: The study included 70 patients with normoalbuminuria type 2 diabetes (DM), 70 patients with microalbuminuria type 2 diabetes (DN), and 60 apparently healthy controls. Fasting plasma glucose, glycosylated hemoglobin, and plasma creatinine were enzymatically assayed. Albuminuria, plasma GAS6, and AXL levels were determined using ELISA. Long noncoding RNAs GAS6-AS1 and GAS6-DT levels were determined in blood using qRT-PCR. Several bioinformatics databases were employed to suggest interactions with the studied biomolecules. RESULTS: GAS6 and AXL were downregulated in DM + DN compared to controls, being the lowest in DN (p < 0.0001). GAS6-DT was upregulated in DM + DN compared to controls, being the highest in DN (p < 0.0001). GAS6-AS1 was higher in DN than in controls (p = 0.013). GAS6, AXL, and GAS6-DT showed fair-to-moderate significant correlations with HbA1c, fasting glucose, creatinine, and albuminuria. ROC curves showed remarkable diagnostic power of GAS6, AXL, and GAS6-DT (AUC = 0.72–1.0), but not GAS6-AS1, in DN and DM, with moderate-to-excellent agreement with conventional diagnostics. CONCLUSIONS: The current findings emphasize the significance of the GAS6/AXL pathway in DM and DN progression, where GAS6, AXL, and GAS6-DT showed significantly altered values in DM, and further in DN, with notable diagnostic power for both diseases. To date, this is the first study confirming the diagnostic power of AXL and GAS6-DT in DN and DM. Future studies are warranted to evaluate therapeutically targeting this pathway to manage DN. Nutrition and Diabetes (2025)15:45 ; https://doi.org/10.1038/s41387-025-00400-y INTRODUCTION Globally, type 2 diabetes prevalence is high, and rising even more in all world regions. Egypt is ranked tenth among the top ten world countries, regarding the number of adults with diabetes, and is ranked second in the Middle East and North Africa region [1]. Diabetic nephropathy (DN) is a widespread microvascular diabetic complication. So far, its etiology and pathogenesis are still indeterminate. It has been related to inflammatory responses, oxidative stress, and hemodynamic disorders resulting from hyperglycemia. Renal tissue changes occur, including glomerular basement membrane thickening, mesangial expansion, glomerulosclerosis, renal vessel and tubulointerstitial lesions, as well as increased fibrosis in renal cells, and kidney function decline. Many patients with diabetic kidney disease are susceptible to rapid progression into end-stage renal disease within months [2]. Several strategies are pursued to identify novel DN biomarkers in blood and urine [3] for the early detection of DN stages and kidney function decline. These include various omics approaches such as metabolomics, peptidomics, multi-omics integration [4], and the study of extracellular vesicles [5], as well as targeted investigations of candidate biomarkers [6]. However, microalbuminuria is still regarded as the “gold standard” for diagnosis and estimation of DN prognosis [7]. Growth arrest-specific gene 6 (GAS6), a growth-factor-like plasma protein, interacts with the TAM family of receptor tyrosine kinases (Tyro3, Mer, and preferentially binds to AXL). The GAS6/ TAM signaling controls processes like cell migration, proliferation, adhesion, and survival. Activation of AXL induces phagocytosis and decreases the expression of proinflammatory cytokines. TAM receptor extracellular domains are cleaved proteolytically by metalloproteases forming soluble forms of the receptors, e.g., sAXL, which circulate in plasma and function as decoys to inactivate their circulating ligand [8]. GAS6 and AXL are expressed in the kidneys. Plasma GAS6 level was significantly lower in patients with diabetes than in healthy controls and decreased further in patients with diabetes and albuminuria than in patients with diabetes and normoalbuminuria [8]. Other studies mentioned that plasma GAS6 level was elevated significantly in participants with diabetes and microalbuminuria 1 Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt. 2Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Cairo 11562, Egypt. 3Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Badr University in Cairo, Cairo 11829, Egypt. 4Department of Biochemistry, Faculty of Pharmacy, Nahda University, Beni Suef 62761, Egypt. ✉email: ; Received: 19 November 2024 Revised: 30 September 2025 Accepted: 3 October 2025 T.K. Motawi et al. 2 than in those with diabetes and normoalbuminuria [9]. GAS6/AXL signaling induced mesangial proliferation and glomerular hypertrophy in DN through the activation of the AKT/mTOR pathway, promoting glomerular injury [10]. Thus, GAS6 was suggested as a potential noninvasive diagnostic biomarker for early diagnosis of DN [8]. Long non-coding RNAs (lncRNAs) are transcripts of 200 nucleotides to 100 kilobases, which do not encode proteins. They assume distinct three-dimensional structures, which allow them to interact with DNA, mRNA, proteins, and other non-coding RNAs. LncRNAs coordinate gene expression, from nuclear and cytoplasmic epigenetic processes (miRNA sponging and chromatin remodeling) to mRNA translation, splicing, and decay. They are involved in cellular processes, including differentiation, proliferation, and apoptosis. Their dysregulation can contribute to a multitude of human diseases, including kidney disease pathogenesis and progression [2] and diabetic complications [11]. The high stability of lncRNAs in biofluids and their ease of detection make them useful predictive biomarkers. LncRNAs may serve as biomarkers as well as therapeutic targets for complications of diabetes [11]. LncRNAs are suggested as targets to develop nextgeneration RNA-based therapy for kidney diseases [2]. Several lncRNAs were upregulated in DN, such as plasmacytoma variant translocation 1 (PVT1), stress-regulated lncRNA hosting a microRNA megacluster (Lnc-MGC), noncoding RNA within the intron region of Erbb4 (Erbb4-IR), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and antisense noncoding RNA in the INK4 locus (ANRIL), while taurine upregulated gene 1 (Tug1) and long intergenic non-protein coding RNA 1619 (Linc01619) were downregulated [12]. GAS6-AS1 is a lncRNA with 902 base pairs and 5 exons, located at 13q34, and is trans (...truncated)