Pharmacological inhibition of Vanin-1 is not protective in models of acute and chronic kidney disease

Discovery of Thiazole Carboxamides as Novel Vanin-1 Inhibitors for Inflammatory Bowel Disease Treatment

Inflammatory bowel disease (IBD) is a clinically heterogeneous disease demanding more therapeutic targets and intervention strategies. Vanin-1, an oxidative stress-regulating protein, has emerged as a promising target for alleviating inflammation and oxidative stress. In this study, a series of thiazole carboxamide derivatives as vanin-1 inhibitors were designed and synthesized. The preferred compound, X17, demonstrated potent inhibition against vanin-1 at the protein, HT-29 cell, and tissue levels, whose binding mode with the target was confirmed via the cocrystal structure. X17 achieved a high bioavailability of 81% in rats, accompanied by concentration-dependent inhibition of serum vanin-1. In a DSS-induced mouse colitis model, X17 exhibited potent anti-inflammatory and antioxidant activities, repressing the inflammatory factor expressions and myeloperoxidase activity, elevating the colonic glutathione reserve, and restoring the intestinal barrier. Collectively, these findings depict the discovery of a potent vanin-1 inhibitor, providing an opportunity for further drug candidate development for treating IBD.

High plasma concentrations of vanin-1 in patients with coronary artery disease

Vanin-1 is a pantetheinase that hydrolyzes pantetheine to pantothenic acid and cysteamine. Vanin-1 has become recognized to be associated with oxidative stress and inflammation. In animal models, vanin-1 was reported to accelerate atherosclerosis. However, no study has reported blood vanin-1 concentrations in patients with coronary artery disease (CAD). We investigated plasma vanin-1 concentrations in 388 patients undergoing elective coronary angiography for suspected CAD. Patients with acute coronary syndrome were excluded. Of the 388 study patients, CAD was found in 207 patients [1-vessel (1-VD), n = 88; 2-vessel (2-VD), n = 66; and 3-vessel disease (3-VD), n = 53]. Plasma vanin-1 concentrations were higher in patients with CAD than in those without CAD (median 0.59 vs. 0.46 ng/mL, P < 0.005). Vanin-1 concentrations in patients without CAD and those with 1-VD, 2-VD, and 3-VD were 0.46, 0.58, 0.57, and 0.61 ng/mL, respectively, and were highest in 3-VD (P < 0.05). A high vainin-1 concentration (> 0.48 ng/mL) was found in 46% of patients without CAD, 61% of 1-VD, 65% of 2-VD, and 66% of 3-VD (P < 0.01). Vanin-1 concentrations significantly correlated with the number of stenotic coronary segments (r = 0.14, P < 0.02). In the multivariate analysis, vanin-1 concentration was a significant factor associated with CAD independent of atherosclerotic risk factors. The odds ratio for CAD was 1.63 (95%CI = 1.04-2.55) for the high vanin-1 concentration of > 0.48 ng/mL. Thus, plasma vanin-1 concentrations in patients with CAD were found to be high and to be associated with the presence and severity of CAD.

VNN1 contributes to the acute kidney injury-chronic kidney disease transition by promoting cellular senescence via affecting RB1 expression

The mechanisms underlying acute kidney injury (AKI) and chronic kidney disease (CKD) progression include interstitial inflammation, cellular senescence, and oxidative stress (OS). Although vanin-1 (VNN1) plays an important role in OS, its contribution to the AKI-CKD transition remains unknown. Here, we explored the roles and mechanisms of VNN1 in the progression of the AKI-CKD transition. We observed that VNN1 expression was upregulated after ischemia/reperfusion (I/R) injury and high VNN1 expression levels were associated with poor renal repair after I/R injury. In VNN1 knockout (KO) mice, recovery of serum creatinine and blood urea nitrogen levels after I/R injury was accelerated and renal fibrosis was inhibited after severe I/R injury. Furthermore, in VNN1 KO mice, senescence of renal tubular cells was inhibited after severe I/R injury, as assessed by P16 expression and SA-β-Gal assays. However, our results also revealed that VNN1 KO renal tubular cells did not resist senescence when OS was blocked. To elucidate the mechanism underlying VNN1-mediated regulation of senescence during the AKI-CKD transition, retinoblastoma 1 (RB1) was identified as a potential target. Our results suggest that the reduced senescence in VNN1 KO renal tubular cells was caused by suppressed RB1 expression and phosphorylation. Collectively, our results unveil a novel molecular mechanism by which VNN1 promotes AKI-CKD transition via inducing senescence of renal tubular cells by activating RB1 expression and phosphorylation after severe renal injury. The present study proposes a new strategy for designing therapies wherein VNN1 can be targeted to obstruct the AKI-CKD transition.

Discovery and characterization of dual inhibitors of human Vanin-1 and Vanin-2 enzymes through molecular docking and dynamic simulation-based approach

The vanins are ectoenzymes with pantetheinase activity and are involved in recycling pantothenic acid (vitamin B5) from pantetheine. Elevated levels of vanin have been linked with the development and severity of several diseases, including steatosis, diabetes, skin diseases, cancer, inflammatory diseases etc. Therefore, vanins have previously been used as a potential drug target to combat related diseases. In this study, we used a molecular docking and molecular dynamic simulation-based approach to screen dual inhibitors of hVnn1, and hVnn2 from a library of 120 chemical candidates. Molecular docking of drug candidates with hVnn1, and hVnn2 using GOLD and MOE revealed that the chemical compound "methotrexate (CID: 126941)" has the highest binding affinity against both the target enzymes which was further validated through molecular dynamic simulation. Toxicity profiling of drug candidates evaluated using Lipinski's rule of five and Molsoft tool, and AdmetSar 2.0 confirms the drug suitability of methotrexate, therefore, suggesting its use as a potential therapeutic agent to inhibit the activity of vainin enzyme in related disease conditions.

Discovery of a Series of Pyrimidine Carboxamides as Inhibitors of Vanin-1

A diaryl ketone series was identified as vanin-1 inhibitors from a high-throughput screening campaign. While this novel scaffold provided valuable probe 2 that was used to build target confidence, concerns over the ketone moiety led to the replacement of this group. The successful replacement of this moiety was achieved with pyrimidine carboxamides derived from cyclic secondary amines that were extensively characterized using biophysical and crystallographic methods as competitive inhibitors of vanin-1. Through optimization of potency and physicochemical and ADME properties, and guided by co-crystal structures with vanin-1, 3 was identified with a suitable profile for advancement into preclinical development.

In Vivo and In Vitro Evaluation of Urinary Biomarkers in Ischemia/Reperfusion-Induced Kidney Injury

Oxidative stress plays an important role in the pathophysiology of acute kidney injury (AKI). Previously, we reported that vanin-1, which is involved in oxidative stress, is associated with renal tubular injury. This study was aimed to determine whether urinary vanin-1 is a biomarker for the early diagnosis of AKI in two experimental models: in vivo and in vitro. In a rat model of AKI, ischemic AKI was induced in uninephrectomized rats by clamping the left renal artery for 45 min and then reperfusing the kidney. On Day 1 after renal ischemia/reperfusion (I/R), serum creatinine (SCr) in I/R rats was higher than in sham-operated rats, but this did not reach significance. Urinary N-acetyl-β-D-glucosaminidase (NAG) exhibited a significant increase but decreased on Day 2 in I/R rats. In contrast, urinary vanin-1 significantly increased on Day 1 and remained at a significant high level on Day 2 in I/R rats. Renal vanin-1 protein decreased on Days 1 and 3. In line with these findings, immunofluorescence staining demonstrated that vanin-1 was attenuated in the renal proximal tubules of I/R rats. Our in vitro results confirmed that the supernatant from HK-2 cells under hypoxia/reoxygenation included significantly higher levels of vanin-1 as well as KIM-1 and NGAL. In conclusion, our results suggest that urinary vanin-1 might be a potential novel biomarker of AKI induced by I/R.