Proteomic identification of vanin-1 as a marker of kidney damage in a rat model of type 1 diabetic nephropathy

Urinary vanin-1 as a novel biomarker for survival in peripheral artery disease

BACKGROUND

Chronic kidney disease is associated with increased rates of incidence, morbidity, and mortality in lower-extremity peripheral artery disease (PAD). No specific marker for a functional risk assessment of kidney disease in PAD is known, especially at the early stages. Thus, we speculated that urinary vanin-1 (uVNN1), a marker of oxidative stress even in early kidney injury, could further stratify outcome assessment in patients with PAD.

METHODS

Patients with stable PAD (n = 304) of the Vienna medical cohort were followed up for up to 10 years and the outcome was assessed by central death database queries. uVNN1 was measured by enzyme-linked immunosorbent assay (ELISA) at study inclusion and normalized to urinary creatinine (uVNN1/Cr). During the observation time (9.3, 7.0-9.8 years), 104 patients died, 54.8% of which were due to cardiovascular causes.

RESULTS

uVNN1/Cr was associated with a urine albumin-creatinine ratio (UACR) (R = 0.166, p = 0.004) but not with an estimated glomerular filtration rate (R = 0.102, p = 0.077). Levels of uVNN1/Cr did not differ between asymptomatic and symptomatic PAD (p = 0.406). Kaplan-Meier curves showed a clear-cut association with higher all-cause (log-rank p = 0.034) and cardiovascular mortality (log-rank p = 0.032) with higher uVNN1/Cr levels. Similarly, significant associations for all-cause (hazard ratio [HR] 1.34, 95% CI [1.08-1.67], p = 0.009) and cardiovascular mortality (HR 1.45, 95% CI [1.06-1.99], p = 0.020) could be seen in multivariable Cox regression models.

CONCLUSIONS

uVNN1/Cr showed an independent association with both all-cause and cardiovascular mortality in patients with PAD and was associated with early kidney disease. Thus, uVNN1 could be a useful marker for risk stratification of kidney disease in PAD.

Vanin1 (VNN1) in chronic diseases: Future directions for targeted therapy

Vanin1 (VNN1) is an exogenous enzyme with pantetheinase activity that mainly exerts physiological functions through enzyme catalysis products, including pantothenic acid and cysteamine. In recent years, the crosstalk between VNN1 and metabolism and oxidative stress has attracted much attention. As a result of the ability of VNN1 to affect multiple metabolic pathways and oxidative stress to exacerbate or alleviate pathological processes, it has become a key component of disease progression. This review discusses the functions of VNN1 in glucolipid metabolism, cysteamine metabolism, and glutathione metabolism to provide perspectives on VNN1-targeted therapy for chronic diseases.

Renoprotective Potency of Sitagliptin versus Pioglitazone in Type 2 Diabetic Patients: Impact on LncMIAT

Background: Diabetes mellitus (DM) represents one of the most important reasons for chronic kidney diseases due to the high level of blood glucose that destructs blood vessels. Objective: The present study focused on investigating the protective impact of sitagliptin on kidney complication in type 2 diabetes mellitus (T2DM) patients in comparison to pioglitazone to examine which has the superior effect against the nephritic complication of DM. Methods: Eighty adult subjects were classified into four groups: control group, pioglitazone-treated T2DM patients (P group), sitagliptin-treated T2DM patients for less than one year (SL group), and sitagliptin-treated T2DM patients for more than one year (SM group). Blood samples were withdrawn from all subjects for analysis of neutrophil gelatinase-associated lipocalin (NGAL), vanin-1, kidney injury molecule-1 (KIM-1), glyoxalase-1 (Glo-1), methylglyoxal (MG), cystatin-C, and interleukin-18 (IL-18) using competitive ELISA kits. Also, long noncoding myocardial infarction associated transcript (lncMIAT) was measured in whole blood using qRT-PCR. Results: The present study revealed that the lncMIAT expression level was significantly higher in the P group as compared to the SL group, SM group, or healthy control group. Additionally, serum NGAL, vanin-1, KIM-1, Glo-1, MG, and cystatin-C were significantly higher in the P group and SL group as compared to the SM group and healthy control group. Conclusion: Sitagliptin protected the kidney through downregulation of lncMIAT besides amelioration of kidney injury marker levels, which was more preferable than in pioglitazone therapy.

Vanin-1-Activated Chemiluminescent Probe: Help to Early Diagnosis of Acute Kidney Injury with High Signal-to-Noise Ratio through Urinalysis

Acute kidney injury (AKI) is a common medical condition with high morbidity and mortality. Although urinalysis provides a noninvasive and convenient diagnostic method for AKI at the molecular level, the low sensitivity of current chemical probes used in urinalysis hinders the time diagnosis of AKI. Herein, we achieved the sensitive and early diagnosis of AKI by the development of a chemiluminescent probe CL-Pa suitable for detection of urinary Vanin-1. Vanin-1 is considered as an early and sensitive biomarker for AKI, while few chemical probes have been applied to for its efficient detection. By virtue of the low autofluorescence interference during urine imaging in the chemiluminescence model, CL-Pa could realize the monitoring of the up-regulated urinary Vanin-1 with a high signal-to-noise ratio (∼588). Importantly, under the help of CL-Pa, the up-regulation of urinary Vanin-1 of cisplatin-induced AKI mice at 12 h post cisplatin injection was detected, which was much earlier than clinical biomarkers (sCr and BUN) and change of kidney histology (48 h post cisplatin injection). Furthermore, using this probe, the fluctuation of urinary Vanin-1 of mice with different degrees of AKI was monitored. This study demonstrated the ability of CL-Pa in sensitively detecting drug-induced AKI through urinalysis and suggested the great potential of CL-Pa for early diagnosis of AKI and evaluate the efficiency of anti-AKI drugs clinically.

Role of Pancreatic Tumour-Derived Exosomes and Their Cargo in Pancreatic Cancer-Related Diabetes

One of the most common and deadly types of pancreatic cancer (PC) is pancreatic ductal adenocarcinoma (PDAC), with most patients succumbing to the disease within one year of diagnosis. Current detection strategies do not address asymptomatic PC; therefore, patients are diagnosed at an advanced stage when curative treatment is often no longer possible. In order to detect PC in asymptomatic patients earlier, the risk factors that could serve as reliable markers need to be examined. Diabetic mellitus (DM) is a significant risk factor for this malignancy and can be both a cause and consequence of PC. Typically, DM caused by PC is known as new-onset, pancreatogenic, pancreoprivic, or pancreatic cancer-related diabetes (PCRD). Although PCRD is quite distinct from type 2 DM (T2DM), there are currently no biomarkers that differentiate PCRD from T2DM. To identify such biomarkers, a better understanding of the mechanisms mediating PCRD is essential. To this end, there has been a growing research interest in recent years to elucidate the role of tumour-derived exosomes and their cargo in the pathogenesis of PCRD. Exosomes derived from tumours can be recognized for their specificity because they reflect the characteristics of their parent cells and are important in intercellular communication. Their cargo consists of proteins, lipids, and nucleic acids, which can be transferred to and alter the behaviour of recipient cells. This review provides a concise overview of current knowledge regarding tumour-derived exosomes and their cargo in PCRD and discusses the potential areas worthy of further study.

Molecular Pathways of Diabetic Kidney Disease Inferred from Proteomics

Diabetic kidney disease (DKD) affects an estimated 20-40% of type 2 diabetes patients and is among the most prevalent microvascular complications in this patient population, contributing to high morbidity and mortality rates. Currently, changes in albuminuria status are thought to be a primary indicator of the onset or progression of DKD, yet progressive nephropathy and renal impairment can occur in certain diabetic individuals who exhibit normal urinary albumin levels, emphasizing the lack of sensitivity and specificity associated with the use of albuminuria as a biomarker for detecting diabetic kidney disease and predicting DKD risk. According to the study, a non-invasive method for early detection or prediction of DKD may involve combining proteomic analytical techniques such second generation sequencing, mass spectrometry, two-dimensional gel electrophoresis, and other advanced system biology algorithms. Another category of proteins of relevance may now be provided by renal tissue biomarkers. The establishment of reliable proteomic biomarkers of DKD represents a novel approach to improving the diagnosis, prognostic evaluation, and treatment of affected patients. In the present review, a series of protein biomarkers that have been characterized to date are discussed, offering a theoretical foundation for future efforts to aid patients suffering from this debilitating microvascular complication.

Clarifying expression patterns by renal lesion using transcriptome analysis and vanin-1 as a potential novel biomarker for renal injury in chickens

Bird death is often caused by renal lesions induced by chemicals. The avian kidney has a renal portal system with significant blood flow that is sensitive to many chemicals. However, early avian biomarkers for kidney injury are yet to be identified. This study aimed to identify novel renal biomarkers. Acute kidney injury (AKI) can be divided into acute interstitial nephritis (AIN) and acute tubular necrosis (ATN). A chicken model of kidney damage was created by an injection of diclofenac or cisplatin, which caused either AIN or ATN, respectively. Microarray analysis was performed to profile the gene expression patterns in the chickens with nephropathy. A gene enrichment analysis suggested that the genes related to responses to external stimuli showed expression changes in both AIN and ATN. However, hierarchical clustering analyses suggested that gene expression patterns differed between AIN and ATN, and the number of biomarkers relating to renal damage was low. To identify early biomarkers for nephropathy, we focused on genes that were induced at various levels of renal damage. The gene, vanin-1 (VNN1) was highly induced in the early stages of renal damage. A quantitative real-time PCR analysis supported this finding. These results suggest VNN1 could be a useful early biomarker of kidney injury in avian species.

Near-Infrared Fluorescent Probe for Imaging and Evaluating the Role of Vanin-1 in Chemotherapy

Pantetheinase (also known as Vanin-1) is highly expressed in the liver, kidneys, and intestine and is closely associated with a number of diseases. Vanin-1 can hydrolyze pantetheine to pantothenic acid (vitamin B5) and cysteamine and participate in the synthesis of glutathione (GSH). GSH is highly expressed in tumor cells and plays a major role in the resistance of tumor cells to cisplatin. Therefore, we urgently need a method to monitor the activity level of Vanin-1 in tumor cells and tissues and elucidate the relationship between the role of Vanin-1 in GSH synthesis and tumor resistance. Herein, we report a Cy-Pa fluorescent probe for imaging Vanin-1 in cells and in vivo that can qualitatively and quantitatively detect the fluctuation of Vanin-1 concentrations in HepG2 and HepG2/DDP cells or tumor tissues of tumor-bearing mice. This probe shows excellent potential in in situ real-time monitoring of endogenous Vanin-1. Moreover, we proved that Vanin-1 can inhibit GSH synthesis using the probe. When the Vanin-1 inhibitor RR6 was used in combination with cisplatin, HepG2 and HepG2/DDP cells showed increased resistance to cisplatin, while the therapeutic efficiency of cisplatin was reduced in HepG2 and HepG2/DDP xenografts. In this study, Vanin-1 was shown to play an important role in the treatment of cancer, and the study of Vanin-1 may provide an idea for the treatment of cancer in the future.

Urinary vanin-1 for predicting acute pyelonephritis in young children with urinary tract infection: a pilot study

BACKGROUND

Vanin-1, an epithelial glycosylphosphatidylolinositol (GPI)-anchored pantetheinase, is a valuable marker of renal injury.

PURPOSE

The aim of this study was to assess the predictive value of vanin-1 in acute pyelonephritis (APN) in comparison to the conventional serum inflammatory markers in children aged 1-24 months with the first episode of urinary tract infection (UTI).

MATERIAL AND METHODS

Urinary vanin-1, vanin-1/Cr ratio, WBC, CRP, PCT were analysed in 58 children with febrile UTI and in 18 children with non-febrile UTI. Febrile UTI group was divided into APN subgroup (n = 29) and non-APN subgroup (n = 29), based on the results of Tc-99m-ethylenedicysteine scan.

RESULTS

The mean vanin-1 level was higher in the APN group compared to the non-febrile UTI group (p = 0.02) and did not differ between APN and non-APN subgroup. In univariate analysis, vanin-1 (p = 0.042), CRP (p < 0.001), PCT (p < 0.001), and WBC (p = 0.022), were associated with APN, but only vanin-1 (p = 0.048) and CRP (p = 0.002) were independent markers of APN. In ROC analysis, vanin-1, with its best cut-off value of 16.53 ng/mL, had worse diagnostic profile (AUC 0.629, sensitivity 58,6%, specificity 63.8%) than CRP, PCT and WBC (AUC: 0.937; 0.880; 0.667, respectively).

CONCLUSIONS

Vanin-1 is not useful for predicting APN, since its diagnostic value is inferior to other conventional serum inflammatory markers.

Red emission ratio fluorescent probe for the activity of vanin-1 and imaging in vivo

Pantetheinase, also known as Vanin-1, catalyzes pantetheine to decompose into the precursor of CoA - pantothenic acid and aminothiol cysteamine. Studies have shown that Vanin-1 plays an important role in many important physiological pathologies. In this paper, a new red emission ratio fluorescent probe DCM-PA (I_{640 nm}/I_{564 nm}) has been implemented to detect the activity of Vanin-1 in cells and vivo. DCM-PA has short response time (30 min), high selectivity and low sensitivity (DL =0.69 ng/mL). Also, we have applied DCM-PA for imaging in cells and mice, and the results have indicated that the probe has a non-negligible potential for monitoring the activity of Vanin-1 in situ, benefiting further to study the role of Vanin-1 in physiology and pathology. In addition, the up-regulation of this enzyme by starvation confirmed the inevitable connection between diabetes and abnormal expression of Vanin-1.

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

Oxidative stress is a key concept in basic, translational, and clinical research to understand the pathophysiology of various disorders, including cardiovascular and renal diseases. Although attempts to directly reduce oxidative stress with redox-active substances have until now largely failed to prove clinical benefit, indirect approaches to combat oxidative stress enzymatically have gained further attention as potential therapeutic strategies. The pantetheinase Vanin-1 is expressed on kidney proximal tubular cells, and its reaction product cysteamine is described to negatively affect redox homeostasis by inhibiting the replenishment of cellular antioxidative glutathione stores. Vanin-1-deficient mice were shown to be protected against oxidative stress damage. The aim of this study was to elucidate whether pharmacological inhibition of Vanin-1 protects mice from oxidative stress-related acute or chronic kidney injury as well. By studying renal ischemia-reperfusion injury in Col4α3-/- (Alport syndrome) mice and in vitro hypoxia-reoxygenation in human proximal tubular cells we found that treatment with a selective and potent Vanin-1 inhibitor resulted in ample inhibition of enzymatic activity in vitro and in vivo. However, surrogate parameters of metabolic and redox homeostasis were only partially and insufficiently affected. Consequently, apoptosis and reactive oxygen species level in tubular cells as well as overall kidney function and fibrotic processes were not improved by Vanin-1 inhibition. We thus conclude that Vanin-1 functionality in the context of cardiovascular diseases needs further investigation and the biological relevance of pharmacological Vanin-1 inhibition for the treatment of kidney diseases remains to be proven.

Visible to Near-Infrared Emission Ratiometric Fluorescent Probe for the Detection of Vanin-1 In Vivo

Pantetheinase (Vanin-1) is an ectoenzyme, which involves the metabolic pathway of coenzyme A (CoA), and can decompose pantetheine into pantothenic acid (CoA precursor) and aminothiol cysteamine. Previous studies have revealed that Vanin-1 with essential biological functions is closely related to many diseases. However, the lack of simple and effective detection methods has severely hindered the further study of Vanin-1's physiological functions. In this work, we have developed a near-infrared (NIR) emission ratio fluorescent probe TMN-PA (I_645 nm/I_568 nm) that enables us to detect Vanin-1 rapidly (in 15 min) with a minimum detection limit of 0.37 ng/mL. What is more, this probe shows excellent potential in in situ real-time monitoring of the endogenous Vanin-1, contributing to further research on Vanin-1 and understanding its mechanisms in physiological pathology. To our knowledge, this probe is the first NIR emission ratio (I_645 nm/I_568 nm) fluorescent probe ever reported to monitor the activity of Vanin-1 in vivo.

Roles Played by Biomarkers of Kidney Injury in Patients with Upper Urinary Tract Obstruction

Partial or complete obstruction of the urinary tract is a common and challenging urological condition caused by a variety of conditions, including ureteral calculi, ureteral pelvic junction obstruction, ureteral stricture, and malignant ureteral obstruction. The condition, which may develop in patients of any age, induces tubular and interstitial injury followed by inflammatory cell infiltration and interstitial fibrosis, eventually impairing renal function. The serum creatinine level is commonly used to evaluate global renal function but is not sensitive to early changes in the glomerular filtration rate and unilateral renal damage. Biomarkers of acute kidney injury are useful for the early detection and monitoring of kidney injury induced by upper urinary tract obstruction. These markers include levels of neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1, kidney injury molecule 1, N-acetyl-b-D-glucosaminidase, and vanin-1 in the urine and serum NGAL and cystatin C concentrations. This review summarizes the pathophysiology of kidney injury caused by upper urinary tract obstruction, the roles played by emerging biomarkers of obstructive nephropathy, the mechanisms involved, and the clinical utility and limitations of the biomarkers.

Systemic Nanoparticle-Mediated Delivery of Pantetheinase Vanin-1 Regulates Lipolysis and Adiposity in Abdominal White Adipose Tissue

Lipolysis in white adipose tissue (WAT) occurs in response to nutritional signals and helps to regulate lipid turnover/adiposity in animals. However, the causal relationships and the mechanisms controlling WAT morphology are not clear. In this report, Vanin-1, a pantetheinase, is shown to be a novel determinant for lipolysis and adiposity. The expression of Vanin-1 in the abdominal WAT is positively correlated with lipolysis both in mice and in humans. Mice with global Vanin-1 deficiency exhibit adipocyte hypertrophy and impaired lipolysis. Use of a nanosystem comprising P3-peptide, chitosan oligosaccharide lactate, and polyethylene glycol that controls Vanin-1 expression in the abdominal WAT shows that WAT-specific Vanin-1 knockdown blocks fasting-induced lipolysis and prevents WAT loss. However, WAT-specific Vanin-1 mRNA restoration rescues impaired lipolysis and improves glucose/insulin intolerance in diabetic db/db mice. Mechanistically, Vanin-1 induces PPARγ activity and subsequently facilitates its activation on the proximal promoters of lipolytic genes. Thus, an essential role of Vanin-1 in the regulation of lipolysis and adiposity is revealed, and a functional RNA delivering strategy for specific intervention of Vanin-1 expression in WAT is shown. These findings provide a promising approach to treat metabolic diseases caused by dysregulation of Vanin-1 and lipolysis.

PGC-1α, Inflammation, and Oxidative Stress: An Integrative View in Metabolism

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is a transcriptional coactivator described as a master regulator of mitochondrial biogenesis and function, including oxidative phosphorylation and reactive oxygen species detoxification. PGC-1α is highly expressed in tissues with high energy demands, and it is clearly associated with the pathogenesis of metabolic syndrome and its principal complications including obesity, type 2 diabetes mellitus, cardiovascular disease, and hepatic steatosis. We herein review the molecular pathways regulated by PGC-1α, which connect oxidative stress and mitochondrial metabolism with inflammatory response and metabolic syndrome. PGC-1α regulates the expression of mitochondrial antioxidant genes, including manganese superoxide dismutase, catalase, peroxiredoxin 3 and 5, uncoupling protein 2, thioredoxin 2, and thioredoxin reductase and thus prevents oxidative injury and mitochondrial dysfunction. Dysregulation of PGC-1α alters redox homeostasis in cells and exacerbates inflammatory response, which is commonly accompanied by metabolic disturbances. During inflammation, low levels of PGC-1α downregulate mitochondrial antioxidant gene expression, induce oxidative stress, and promote nuclear factor kappa B activation. In metabolic syndrome, which is characterized by a chronic low grade of inflammation, PGC-1α dysregulation modifies the metabolic properties of tissues by altering mitochondrial function and promoting reactive oxygen species accumulation. In conclusion, PGC-1α acts as an essential node connecting metabolic regulation, redox control, and inflammatory pathways, and it is an interesting therapeutic target that may have significant benefits for a number of metabolic diseases.

Vanin 1: Its Physiological Function and Role in Diseases

The enzyme vascular non-inflammatory molecule-1 (vanin 1) is highly expressed at gene and protein level in many organs, such as the liver, intestine, and kidney. Its major function is related to its pantetheinase activity; vanin 1 breaks down pantetheine in cysteamine and pantothenic acid, a precursor of coenzyme A. Indeed, its physiological role seems strictly related to coenzyme A metabolism, lipid metabolism, and energy production. In recent years, many studies have elucidated the role of vanin 1 under physiological conditions in relation to oxidative stress and inflammation. Vanin’s enzymatic activity was found to be of key importance in certain diseases, either for its protective effect or as a sensitizer, depending on the diseased organ. In this review, we discuss the role of vanin 1 in the liver, kidney, intestine, and lung under physiological as well as pathophysiological conditions. Thus, we provide a more complete understanding and overview of its complex function and contribution to some specific pathologies.

A Novel Biomarker for Acute Kidney Injury, Vanin-1, for Obstructive Nephropathy: A Prospective Cohort Pilot Study

Background: Vanin-1 is a novel acute kidney injury (AKI) biomarker that has not been clinically investigated as a biomarker for obstructive nephropathy. This study investigated the diagnostic value of vanin-1 as a biomarker for adult obstructive nephropathy by comparing it to existing AKI biomarkers. Methods: A total of 49 patients, 21 controls, and 28 hydronephrosis (HN) cases were assessed. AKI biomarkers in bladder (BL) urine and renal pelvic (RP) urine in the HN group were compared to each BL marker in the control group. In a subgroup of cases receiving interventions for obstructive nephropathy, the BL values of each biomarker were assessed after the intervention. Results: RP vanin-1 levels were significantly higher while BL vanin-1 levels were marginally higher in the HN group than in the control group. The area under the receiver operating characteristics curve values for RP and BL vanin-1 were 0.9778 and 0.6386, respectively. In multivariate analyses, BL vanin-1 and N-acetyl-β-D-glucosaminidase (NAG), but not kidney injury molecule-1 (KIM-1) or neutrophil gelatinase-associated lipocalin (NGAL), were independent factors for predicting the presence of HN. In cases receiving interventions, vanin-1 decreased significantly from 1 week after the intervention in cases of moderate to severe obstructive nephropathy compared to RP values at baseline. Conclusion: Urinary vanin-1 is a useful biomarker to detect and monitor the clinical course of obstructive nephropathy.

Exosomal proteomic analysis reveals changes in the urinary proteome of rats with unilateral ureteral obstruction

Congenital urinary tract obstruction (UTO) is a commonly noted disorder with the potential to cause permanent loss of renal function. Due to the possibility of spontaneous resolution, postnatal management strategies require lengthy and invasive surveillance methods to monitor the status of renal function and severity of obstruction. Here, a quantitative proteome analysis of urinary exosomes from weanling rats with surgically introduced UTO identifies a number of candidate biomarkers with the potential to improve diagnostic and prognostic methods for this disease. Using gel-assisted digestion coupled to liquid chromatography/tandem mass spectrometry (LC–MS/MS), 318 proteins were identified. Relative protein quantitation by spectral counting showed 190 proteins with significant changes in abundance due to either partial or complete obstruction. Numerous proteins identified here have been shown to be similarly altered in abundance in other renal diseases that cause tubule apoptosis and interstitial fibrosis. Extrapolating the role of the proteins showing quantifiable changes in abundance here from other forms of renal disease suggests they have potential for clinical applicability as biomarkers of congenital UTO. Included in the list of identified proteins are markers of apoptosis, oxidative stress, fibrosis, inflammation, and tubular cell damage, which are commonly associated with UTO. This study therefore provides a number of candidate biomarkers that, following validation in children experiencing UTO, have the potential to improve postnatal management of this disease.

Proteome profiling in the aorta and kidney of type 1 diabetic rats

Diabetes is associated with a number of metabolic and cardiovascular risk factors that contribute to a high rate of microvascular and macrovascular complications. The risk factors and mechanisms that contribute to the development of micro- and macrovascular disease in diabetes are not fully explained. In this study, we employed mass spectrometric analysis using tandem LC-MS/MS to generate a proteomic profile of protein abundance and post-translational modifications (PTM) in the aorta and kidney of diabetic rats. In addition, systems biology analyses were employed to identify key protein markers that can provide insights into molecular pathways and processes that are differentially regulated in the aorta and kidney of type 1 diabetic rats. Our results indicated that 188 (111 downregulated and 77 upregulated) proteins were significantly identified in the aorta of diabetic rats compared to normal controls. A total of 223 (109 downregulated and 114 upregulated) proteins were significantly identified in the kidney of diabetic rats compared to normal controls. When the protein profiles from the kidney and aorta of diabetic and control rats were analyzed by principal component analysis, a distinct separation of the groups was observed. In addition, diabetes resulted in a significant increase in PTM (oxidation, phosphorylation, and acetylation) of proteins in the kidney and aorta and this effect was partially reversed by insulin treatment. Ingenuity pathway analysis performed on the list of differentially expressed proteins depicted mitochondrial dysfunction, oxidative phosphorylation and acute phase response signaling to be among the altered canonical pathways by diabetes in both tissues. The findings of the present study provide a global proteomics view of markers that highlight the mechanisms and putative processes that modulate renal and vascular injury in diabetes.

A comprehensive analysis and annotation of human normal urinary proteome

Biomarkers are measurable changes associated with the disease. Urine can reflect the changes of the body while blood is under control of the homeostatic mechanisms; thus, urine is considered an important source for early and sensitive disease biomarker discovery. A comprehensive profile of the urinary proteome will provide a basic understanding of urinary proteins. In this paper, we present an in-depth analysis of the urinary proteome based on different separation strategies, including direct one dimensional liquid chromatography–tandem mass spectrometry (LC/MS/MS), two dimensional LC/MS/MS, and gel-eluted liquid fraction entrapment electrophoresis/liquid-phase isoelectric focusing followed by two dimensional LC/MS/MS. A total of 6085 proteins were identified in healthy urine, of which 2001 were not reported in previous studies and the concentrations of 2571 proteins were estimated (spanning a magnitude of 10⁶) with an intensity-based absolute quantification algorithm. The urinary proteins were annotated by their tissue distribution. Detailed information can be accessed at the “Human Urine Proteome Database” (www.urimarker.com/urine).

Role of HSP60 (HSPD1) in diabetes-induced renal tubular dysfunction: regulation of intracellular protein aggregation, ATP production, and oxidative stress

Because underlying mechanisms of diabetic nephropathy/tubulopathy remained poorly understood, we aimed to define a key protein involving in hyperglycemia-induced renal tubular dysfunction. All altered renal proteins identified from previous large-scale proteome studies were subjected to global protein network analysis, which revealed heat shock protein 60 (HSP60, also known as HSPD1) as the central node of protein-protein interactions. Functional validation was performed using small interfering RNA (siRNA) to knock down HSP60 (siHSP60). At 48 h after exposure to high glucose (HG) (25 mM), Madin-Darby canine kidney (MDCK) renal tubular cells transfected with controlled siRNA (siControl) had significantly increased level of HSP60 compared to normal glucose (NG) (5.5 mM), whereas siHSP60-transfected cells showed a dramatically decreased HSP60 level. siHSP60 modestly increased intracellular protein aggregates in both NG and HG conditions. Luciferin-luciferase assay showed that HG modestly increased intracellular ATP, and siHSP60 further enhanced such an increase. OxyBlot assay showed significantly increased level of oxidized proteins in HG-treated siControl-transfected cells, whereas siHSP60 caused marked increase of oxidized proteins under the NG condition. However, the siHSP60-induced accumulation of oxidized proteins was abolished by HG. In summary, our data demonstrated that HSP60 plays roles in regulation of intracellular protein aggregation, ATP production, and oxidative stress in renal tubular cells. Its involvement in HG-induced tubular cell dysfunction was most likely via regulation of intracellular ATP production.-Aluksanasuwan, S., Sueksakit, K., Fong-ngern, K., Thongboonkerd, V. Role of HSP60 (HSPD1) in diabetes-induced renal tubular dysfunction: regulation of intracellular protein aggregation, ATP production, and oxidative stress.

Screening for potential serum biomarkers in rat mesangial proliferative nephritis

Mesangial proliferative nephritis (MesPGN) is a common kidney disease worldwide. The main feature of the disease is mesangial cell proliferation-induced injury to kidney function. In this study, we explored serum biomarkers for kidney function injury in anti-Thy1 nephritis. We found that mesangial proliferation were increased on days 5 and 7, and recovered by day 14 in anti-Thy1 nephritis. 24-h urine protein, the ratio of urine protein to urine creatine, serum creatine, and blood urea nitrogen, were increased at days 5 and 7 in the model. We found that TXN, BET1, PrRP, VGF, and NPS differed strongly from controls on days 5 and, associated with kidney injury when detected by SELDI-TOF MS. Moreover, we applied LC-MS to detect differential protein expression and found A2M, C3, ITIH4, ITIH3, VDBP, AFM, and SERPINF2 to be upregulated, and ES1, HPX, SERPINC1, SERPINA1F, SERPINA4, SERPINA3K, SPI, TF, VNN3, SERPINF1, and PON1 to be downregulated, on days 5 and 7, associated with kidney injury. The levels of VNN3 and VDBP were validated by Western blotting. Overall, this study explored a group of candidate biomarkers of mesangial proliferation inducing kidney injury, to provide the basis of an assessment model for MesPGN in the future.

Urinary Proteomics for Diagnosis and Monitoring of Diabetic Nephropathy

The last decade has seen a surge in publications describing novel biomarkers for early detection of diabetic nephropathy (DN), but as yet none have outperformed albuminuria in well-designed prospective studies. This is partially attributable to our incomplete understanding of the many complex interrelated mechanisms underlying DN development, a heterogeneous process unlikely to be captured by a single biomarker. Proteomics offers the advantage of simultaneously analysing the entire protein content of a biological sample, and the technique has gained attention as a potential tool for a more accurate diagnosis of disease at an earlier stage as well as a means by which to unravel the pathogenesis of complex diseases such as DN using an untargeted approach. This review will discuss the potential of proteomics as both a clinical and research tool, evaluating exploratory work in animal models as well as diagnostic potential in human subjects.

VNN1, a potential biomarker for pancreatic cancer-associated new-onset diabetes, aggravates paraneoplastic islet dysfunction by increasing oxidative stress

In our previous clinical microarray analysis, we were the first to report on Vanin-1 (VNN1) as a novel clinically derived biomarker of pancreatic cancer-associated new-onset diabetes (PCAND). The functional mechanisms of VNN1 in the pathogenesis of PCAND, however, are not completely understood. In the present study, we further extend our previous clinical study to include laboratory research. The functions and mechanisms of neoplastic overexpressed VNN1 in PCAND have been explored using a co-culture model. Furthermore, the serum concentrations and discrimination power of downstream molecules of VNN1 were tested in a PCAND cohort. Pancreatic ductal adenocarcinoma (PDA) overexpressed VNN1 further aggravates paraneoplastic islet dysfunction; decreases in GSH/PPAR-γ concentrations and increases in ROS/cysteamine might be primary cause of this effect. Clinical serum analyses revealed that the expression profiles of these molecules were aberrant in the PCAND group. Our results further demonstrated that PCAND is a type of paraneoplastic diabetes. As the only clinically derived biomarker for PCAND screening available today, the biological role of VNN1 in triggering oxidative stress within the pancreatic microenvironment is important. The molecules downstream of VNN1 are also potential biomarkers for PCAND screening.

Role of the Vnn1 pantetheinase in tissue tolerance to stress

Pantetheinase is an ubiquitous enzyme which hydrolyses D-pantetheine into cysteamine and pantothenate (vitamin B5) on the dissimilative pathway of CoA. Pantetheinase isoforms are encoded by the Vnn (vanin) genes and Vnn1 is the predominant tissue isoform in mice and humans. In the present article, we review the results showing the regulation of Vnn1 expression during developmental, repair and inflammatory situations and the impact of a Vnn1 deficiency in mouse models of pathologies. We document the involvement of the Vnn1 pantetheinase in situations of increased tissue needs and propose that Vnn1 through recycling of pantothenate and release of cysteamine in tissues participates in the adaptive response of the tissue to stress.

Glycosylation patterns of kidney proteins differ in rat diabetic nephropathy

Diabetic nephropathy often progresses to end-stage kidney disease and, ultimately, to renal replacement therapy. Hyperglycemia per se is expected to have a direct impact on the biosynthesis of N- and O-linked glycoproteins. This study aims to establish the link between protein glycosylation and progression of experimental diabetic kidney disease using orthogonal methods. Kidneys of streptozotocin-diabetic and control rats were harvested at three different time points post streptozotocin injection. A panel of 12 plant lectins was used in the screening of lectin blots. The lectins UEAI, PHA-E, GSI, PNA, and RCA identified remarkable disease-associated differences in glycoprotein expression. Lectin affinity chromatography followed by mass spectrometric analyses led to the identification of several glycoproteins involved in salt-handling, angiogenesis, and extracellular matrix degradation. Our data confirm a substantial link between glycosylation signature and diabetes progression. Furthermore, as suggested by our findings on dipeptidyl peptidase-IV, altered protein glycosylation may reflect changes in biochemical properties such as enzymatic activity. Thus, our study demonstrates the unexplored potential of protein glycosylation analysis in the discovery of molecules linked to diabetic kidney disease.

Urinary Kim-1 is a sensitive biomarker for the early stage of diabetic nephropathy in Otsuka Long-Evans Tokushima Fatty rats

Although urinary albumin is the well-known non-invasive marker for diabetic nephropathy, its sensitivity is relatively low. To select more adequate marker, we examined whether urinary tubular markers were more sensitive than albumin using spontaneous type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The OLETF rats exhibited histopathological alterations in glomeruli and tubules at 14 weeks of age, but there were no significant differences in the urinary albumin between OLETF and control, Long-Evans Tokushima Otsuka (LETO), rats at 10-16 weeks of age. In the OLETF rats, urinary excretions of N-acetyl-β-d-glucosaminidase and neutrophil gelatinase-associated lipocalin did not increase at least until 20 weeks of age, and urinary vanin-1 transiently increased at 18 weeks of age. On the other hand, urinary kidney injury molecule-1 (Kim-1) in the OLETF rats significantly increased at 14 weeks of age, and the elevation continued up to 22 weeks of age. In a clinical study, urinary KIM-1 levels tended to be higher in type 2 diabetic patients with and without albuminuria than in control subjects. These results suggest that compared to urinary albumin, urinary Kim-1 is a more sensitive biomarker for the detection of early stage of nephropathy in these type 2 diabetic animals. Merit of urinary KIM-1 in diabetic patients remains to be determined.

Vanin-1 is a key activator for hepatic gluconeogenesis

Vanin-1 (VNN1) is a liver-enriched oxidative stress sensor that has been implicated in the regulation of multiple metabolic pathways. Clinical investigations indicated that the levels of VNN1 were increased in the urine and blood of diabetic patients, but the physiological significance of this phenomenon remains unknown. In this study, we demonstrated that the hepatic expression of VNN1 was induced in fasted mice or mice with insulin resistance. Gain- and loss-of-function studies indicated that VNN1 increased the expression of gluconeogenic genes and hepatic glucose output, which led to hyperglycemia. These effects of VNN1 on gluconeogenesis were mediated by the regulation of the Akt signaling pathway. Mechanistically, vnn1 transcription was activated by the synergistic interaction of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and hepatocyte nuclear factor-4α (HNF-4α). A chromatin immunoprecipitation analysis indicated that PGC-1α was present near the HNF-4α binding site on the proximal vnn1 promoter and activated the chromatin structure. Taken together, our results suggest an important role for VNN1 in regulating hepatic gluconeogenesis. Therefore, VNN1 may serve as a potential therapeutic target for the treatment of metabolic diseases caused by overactivated gluconeogenesis.

From target discovery to clinical trials with armed antibody products

Conventional chemotherapy of serious conditions (e.g., cancer and chronic inflammatory diseases) relies on the use of potent bioactive agents, which do not preferentially localize at the site of disease and which may harm healthy tissues. Intense pharmaceutical research efforts are being devoted to the development of targeted therapeutic agents, capable of selectively homing to diseased tissues, while sparing normal body structures. Biological mass spectrometry and chemical proteomics have revolutionized the way targets for ligand-based pharmacodelivery applications are discovered. In this article, we present a personal account on research activities in the field for the last decade, outlining our experience in the discovery of accessible biomarkers and in the development of potent targeted therapeutic agents.

BIOLOGICAL SIGNIFICANCE

The present review discusses evolution of proteomic methodologies applied to the discovery of new targets for therapeutic intervention in cancer and inflammatory diseases. Chemical proteomics-driven target discovery allowed the development of new classes of antibody-based targeting biologics, which are having an impact in the oncological and chronic inflammation clinical research. This article is part of a Special Issue entitled: 20years of Proteomics in memory of Viatliano Pallini. Guest Editors: Luca Bini, Juan J. Calvete, Natacha Turck, Denis Hochstrasser and Jean-Charles Sanchez.

Stage-specific quantitative changes in renal and urinary proteome during the progression and development of streptozotocin-induced diabetic nephropathy in rats

Diabetic nephropathy (DN) is a microvascular complication associated with diabetes causing slow deterioration of kidneys leading to end-stage renal disease. Timely intervention and diagnosis are crucial in order to ameliorate and halt the progression of DN. Current diagnosis of DN consists of urine assays for detection of microalbuminuria, which have inadequate specificity and sensitivity. Hence, there arises a need to discover stage-specific biomarkers which can aid in the early detection of DN and also in identifying the mechanisms underlying pathogenesis of DN. Therefore the present study was undertaken to identify the differentially expressed proteins in the urine and to examine the pattern of proteomic changes occurring in the rat kidneys during the course of progression of streptozotocin-induced model of DN in rats. Two-dimensional gel electrophoresis coupled to MALDI-TOF mass spectrometry was employed to identify the differentially expressed proteins under diabetic conditions. Among the identified proteins Calgranulin A and Calgranulin B appeared in the urinary proteome at the fourth week of induction of diabetes while we recorded a time-dependent decrease in the expression of major urinary protein (alpha 2u globulin) in the urine as well as kidneys of diabetic rats. Parallel monitoring of targeted proteomic changes in the renal proteome revealed an increase in histone H2B phosphorylation at serine14 along with a gradual decrease in Bcl-2 and MMP-13 expression during the course of progression and development of streptozotocin-induced DN.

Subfractionation, characterization, and in-depth proteomic analysis of glomerular membrane vesicles in human urine

Urinary exosome-like vesicles (ELVs) are a heterogenous mixture (diameter 40–200nm) containing vesicles shed from all segments of the nephron including glomerular podocytes. Contamination with Tamm Horsfall protein (THP) oligomers has hampered their isolation and proteomic analysis. Here we improved ELV isolation protocols employing density centrifugation to remove THP and albumin, and isolated a glomerular membranous vesicle (GMV) enriched subfraction from 7 individuals identifying 1830 proteins and in 3 patients with glomerular disease identifying 5657 unique proteins. The GMV fraction was composed of podocin/podocalyxin positive irregularly shaped membranous vesicles and podocin/podocalyxin negative classical exosomes. Ingenuity pathway analysis identified integrin, actin cytoskeleton and RhoGDI signaling in the top three canonical represented signaling pathways and 19 other proteins associated with inherited glomerular diseases. The GMVs are of podocyte origin and the density gradient technique allowed isolation in a reproducible manner. We show many nephrotic syndrome proteins, proteases and complement proteins involved in glomerular disease are in GMVs and some were shed in the disease state (nephrin, TRPC6 and INF2 and PLA2R). We calculated sample sizes required to identify new glomerular disease biomarkers, expand the ELV proteome and provide a reference proteome in a database that may prove useful in the search for biomarkers of glomerular disease.

In vivo intravascular biotinylation of Schistosoma bovis adult worms and proteomic analysis of tegumental surface proteins

Schistosoma bovis is a blood-dwelling fluke of ruminants that lives for years inside the vasculature of their hosts. The parasite tegument covers the surface of the worms and plays a key role in the host-parasite relationship. The parasite molecules expressed at the tegument surface are potential targets for immune or drug intervention. The purpose of this work was the identification of the proteins expressed in vivo on the surface of the tegument of S. bovis adult worms. To accomplish this we used a method based on in vivo vascular perfusion of mice infected with S. bovis which allowed the labelling of the surface of the worms inside the blood vasculature. The biotinylation of parasite inside blood vessels prevents the handling of worms in vitro and hence possible damage to the tegument that could produce results that would be difficult to interpret. Trypsin digestion of biotinylated proteins and subsequent liquid chromatography and tandem mass spectrometry analysis (LC-MS/MS) resulted in the identification on the S. bovis tegument of 80 parasite proteins and 28 host proteins. The proteins identified were compared with the findings from other proteomic studies of the schistosome surface. The experimental approach used in this work is a reliable method for selective investigation of the surface of the worms and provides valuable information about the exposed protein repertoire of the tegument of S. bovis in the environmental conditions that the parasite faces inside the blood vessels.

BIOLOGICAL SIGNIFICANCE

To identify the proteins expressed on the surface of the tegument of S. bovis adult worms we used a method based on in vivo vascular perfusion, with biotin, of mice infected with S. bovis which allowed the labelling of the surface of the worms inside the blood vasculature. This methodology prevents the handling of worms in vitro and hence possible damage to the tegument that could produce results that would be difficult to interpret. This work is the first in which vascular perfusion has been used to investigate, in vivo, the protein exposed by an intravascular pathogen on its surface to the host, and provides valuable information about the exposed protein repertoire of the tegument of S. bovis in the environmental conditions that the parasite faces inside the blood vessels.

Linkage between coenzyme a metabolism and inflammation: roles of pantetheinase

Pantetheinase is an enzyme hydrolyzing pantetheine, an intermediate of the coenzyme A degradation pathway. Pantetheinase has long been considered as the enzyme that recycles pantothenic acid (vitamin B5) generated during coenzyme A breakdown. Genetic analyses showed that mammals have multiple genes known as vanin family genes. Recent studies using mice lacking the vanin-1 gene (pantetheinase gene) suggest that pantetheinase is actively involved in the progression of inflammatory reactions by generating cysteamine. Additional studies using human leukocytes demonstrate that human neutrophils have abundant pantetheinase proteins on the surface and inside the cells. The second pantetheinase protein, GPI-80/VNN2, is suggested to work as a modulator of the function of Mac-1 (CD11b/CD18), an adhesion molecule important to neutrophil functions. This review delineates the characteristics of the pantetheinase/vanin gene family and how they affect inflammation.

Non-alcoholic fatty liver disease is not related to the incidence of diabetic nephropathy in Type 2 Diabetes

To analyze the association between non-alcoholic fatty liver disease (NAFLD) and the incidence of diabetic nephropathy in patients with type 2 diabetes, the incidence of diabetic nephropathy was assessed in 413 type 2 diabetic patients, by testing the 24 h urinary albumin excretion rate (UAER). The NAFLD was diagnosed based on patient's medical history and liver ultrasound. The difference in diabetic nephropathy incidence between patients with and without NAFLD was tested by X². Multivariate logistic regression analysis was used to assess the factors associated with diabetic nephropathy among type 2 diabetic patients. Total 363 out of 413 type 2 diabetic patients were enrolled in this study. The incidences of NAFLD and diabetic nephropathy in participants were approximately 56% (202/363) and 38% (137/363) respectively, and there was no significant difference in the prevalence of diabetic nephropathy between patients with and without NAFLD (37.1% vs. 38.5%, p = 0.787). The duration of diabetes (odds ratio [OR] 1.065, 95% confidence interval [CI] 1.014--1.120, p = 0.012), waist circumference (OR 1.077, 95% CI 1.040--1.116, p = 0.000), and fasting blood glucose (FBG; OR 1.136, 95% CI 1.023--1.1262, p = 0.017) were significantly associated with diabetic nephropathy, whereas sex, high blood pressure, total cholesterol (TC), triglyceride (TG), and ankle brachial pressure index (ABI) were not significantly associated with the disorder. The present results suggest that NAFLD is not related to the incidence of diabetic nephropathy in type 2 diabetes, but the duration of diabetes, waist circumference, and FBG are important factors for diabetic nephropathy in type 2 diabetes.

Down-regulation of alpha-2u globulin in renal mitochondria of STZ-induced diabetic rats observed by a proteomic method

AIM

To identify the changes of mitochondrial protein expression in diabetic renal parenchyma and to characterize their molecular functions and biological processes in diabetes.

METHODS

Mitochondrial proteins extracted from renal parenchyma mitochondria of streptozotocin-induced diabetic rats and normal rats were separated by two-dimensional polyacrylamide gel electrophoresis and identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry.

RESULTS

Eleven proteins from 533 visualized protein spots displayed significant different expressions in mitochondria of diabetic kidneys compared with those in normal ones. Among these altered proteins, two proteins with the most obvious changes in protein expression were identified as alpha-2u globulin (mature protein, named A2) and its proteolytically modified form (named A2-fragment) respectively. These proteins were found in mitochondria of male rat renal parenchyma and were proved to be down-regulated in diabetic rats simultaneously.

CONCLUSION

Our results suggest that down-regulation of alpha-2u globulin may be associated with an abnormal β-oxidation of long-chain fatty acids during diabetes. The decreased expression of A2-fragment in renal mitochondria of diabetic nephropathy may reduce fatty acid β-oxidation, which leads to a diminished energy supply from mitochondria to kidney tissue and the deposition of a large number of fatty acids in the kidney, ultimately causing and aggravating kidney damage. In conclusion, these findings may be helpful for understanding the molecular mechanism of diabetic nephropathy.

Minireview: progress and challenges in proteomics data management, sharing, and integration

The proteome represents the identity, expression levels, interacting partners, and posttranslational modifications of proteins expressed within any given cell. Proteomic studies aim to census the quantitative and qualitative factors regulating the biological relationships of proteins acting in concert as functional cellular networks. In the field of endocrinology, proteomics has been of considerable value in determining the function and mechanism of action of endocrine signaling molecules in the cell membrane, cytoplasm, and nucleus and for the discovery of proteins as candidates for clinical biomarkers. The volume of data that can be generated by proteomics methodologies, up to gigabytes of data within a few hours, brings with it its own logistical hurdles and presents significant challenges to realizing the full potential of these datasets. In this minireview, we describe selected current proteomics methodologies and their application in basic and translational endocrinology before focusing on mass spectrometry as a model for current progress and challenges in data analysis, management, sharing, and integration.

Pre-clinical markers for diagnosis of diabetic nephropathy in patients with type 1 diabetes mellitus

Due to progressive nature of diabetic nephropathy (DN) and limited effectiveness of therapeutic efforts at clinically overt stages, diagnosisof pre-clinical (and, therefore, potentially reversible) DN is especially important. To date, however, test for microalbuminuriaremains the only technique applicable for early diagnostics of DN. Current review addresses search for potential markers of pre-clinical stage of DN in patients with type 1 diabetes mellitus and embracesdata from latest experimental and clinical studies in this area.

Urinary vanin-1 as a novel biomarker for early detection of drug-induced acute kidney injury

Drug-induced nephrotoxicity is a serious problem in patients with hospital-acquired acute kidney injury (AKI). A new renal biomarker is needed because traditional markers are not sensitive for early detection of drug-induced AKI. In a recent study, we demonstrated that vanin-1 is a novel candidate biomarker of nephrotoxicant-induced kidney injury. The objective of the present study is to determine whether the increase in urinary vanin-1 is detected before the elevations of serum creatinine or urinary N-acetyl-β-glucosaminidase (NAG), kidney injury molecule-1 (Kim-1), and neutrophil gelatinase-associated lipocalin (NGAL) in the two well established animal models of drug-induced AKI. After the administration of a higher dose of cisplatin (10 mg/kg, a single intraperitoneal dose) or gentamicin (120 mg/kg per day, once daily intraperitoneal dose for 9 days), urinary vanin-1 was detected earlier than the other biomarkers. In rats treated with a lower dose of cisplatin (5 mg/kg, a single intraperitoneal dose) or gentamicin (40 mg/kg per day, once daily intraperitoneal dose for 9 days), serum creatinine and urinary NAG were not changed throughout the study period, whereas urinary vanin-1, Kim-1, and NGAL were significantly increased. The renal vanin-1 protein levels were significantly decreased in rats treated with the higher dose of cisplatin on day 5 and gentamicin on day 9, and the immunofluorescence analyses confirmed that vanin-1 immunoreactivity in tubular cells was reduced with the time after the dose of cisplatin, indicating that urinary vanin-1 was leaked from tubular cells. These results suggest that, compared with urinary Kim-1 and NGAL, urinary vanin-1 is an earlier and equally sensitive biomarker for drug-induced AKI.

Vanin-1: a potential biomarker for nephrotoxicant-induced renal injury

Because traditional markers for detecting renal injury are generally insensitive and nonspecific, we tried to identify some useful biomarkers. Microarray analyses and quantitative real-time PCR using human renal tubular cells showed that the mRNA expression of VNN-1 which encodes vanin-1, increased after the exposure of these cells to organic solvents (allyl alcohol, ethylene glycol, formaldehyde, chloroform, and phenol) for 24h. The mRNA levels of other inflammation-related molecules such as monocyte chemoattractant protein 1 (MCP-1) and kidney injury molecule-1 (KIM-1) also increased after the exposure to organic solvents, although their elevations were slower than that of vanin-1. In rats treated with ethylene glycol for 3 weeks, tubular injury was detected by histological examination, but not by traditional biomarkers including serum creatinine and urinary N-acetyl-β-glucosaminidase. The mRNA levels of vanin-1 and Kim-1, but not MCP-1, significantly elevated in the renal cortices of ethylene glycol-exposed rats. On immunofluorescence analyses, vanin-1 signal was detected specifically in the renal tubules with a remarkable expression in the ethylene glycol-treated rats. As a result, compared with control group, higher urinary and serum concentrations of vanin-1 were observed in the ethylene glycol-treated group. These results suggest that vanin-1 is a useful and rapid biomarker for renal tubular injury induced by organic solvents.