Dataset Information

Face-specific binding of prothrombin fragment 1 and human serum albumin to inorganic and urinary calcium oxalate monohydrate crystals.

ABSTRACT:

Objective

To compare the intracrystalline distributions of prothrombin fragment 1 (PTF1) and human serum albumin (HSA) within inorganic and urinary calcium oxalate (CaOx) monohydrate (COM) crystals and to determine whether binding of PTF1 can be explained by interactions between particular gamma-carboxyglutamic (Gla) residues and atomic arrays on individual faces of the COM crystal. MATERIALS AND METHODS COM: crystals were precipitated from inorganic solutions and ultrafiltered urine containing fluorescent HSA or PTF1 at different relative concentrations and examined by fluorescence microscopy. Accelrys Materials Studio and Discovery Studio were used to model the binding of PTF1 to the top, side and apical faces of the COM crystal.

Results

PTF1 alone always adsorbed predominantly to the COM apical surfaces, while HSA bound principally to the side faces under inorganic conditions, but to the apical faces in urine. In the presence of each other, both proteins competed for adsorption to the apical faces, with attachment of PTF1 dominating over that of HSA. Modelling showed that urinary PTF1 had equal theoretical bonding potential for all three COM surfaces.

Conclusions

(i) Anisotropic inclusion of HSA and PTF1 into urinary and inorganic COM crystals results from their preferential binding to specific COM faces; (ii) the binding preference of HSA differs under inorganic and urinary conditions; (iii) preferential binding of PTF1 to the apical faces of COM is more complex than can be explained by interactions between Gla groups and surface atomic arrays; (iv) future studies of interactions between urinary proteins and stone mineral crystal surfaces should be performed in urine.

SUBMITTER: Cook AF

PROVIDER: S-EPMC2771741 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

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Publications

Face-specific binding of prothrombin fragment 1 and human serum albumin to inorganic and urinary calcium oxalate monohydrate crystals.

Cook Alison F AF Grover Phulwinder K PK Ryall Rosemary L RL

BJU international 20081113 6

<h4>Objective</h4>To compare the intracrystalline distributions of prothrombin fragment 1 (PTF1) and human serum albumin (HSA) within inorganic and urinary calcium oxalate (CaOx) monohydrate (COM) crystals and to determine whether binding of PTF1 can be explained by interactions between particular gamma-carboxyglutamic (Gla) residues and atomic arrays on individual faces of the COM crystal. MATERIALS AND METHODS COM: crystals were precipitated from inorganic solutions and ultrafiltered urine con ...[more]

PMID: 19021614

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Project description:Oxidative stress, a well-known cause of stress-induced premature senescence (SIPS), is increased in patients with calcium oxalate (CaOx) kidney stones (KS). Oxalate and calcium oxalate monohydrate (COM) induce oxidative stress in renal tubular cells, but to our knowledge, their effect on SIPS has not yet been examined. Here, we examined whether oxalate, COM, or urine from patients with CaOx KS could induce SIPS and telomere shortening in human kidney (HK)-2 cells, a proximal tubular renal cell line. Urine from age- and sex-matched individuals without stones was used as a control. In sublethal amounts, H2O2, oxalate, COM, and urine from those with KS evoked oxidative stress in HK-2 cells, indicated by increased protein carbonyl content and decreased total antioxidant capacity, but urine from those without stones did not. The proportion of senescent HK-2 cells, as indicated by SA-βgal staining, increased after treatment with H2O2, oxalate, COM, and urine from those with KS. Expression of p16 was higher in HK-2 cells treated with H2O2, oxalate, COM, and urine from those with KS than it was in cells treated with urine from those without stones and untreated controls. p16 was upregulated in the SA-βgal positive cells. Relative telomere length was shorter in HK-2 cells treated with H2O2, oxalate, COM, and urine from those with KS than that in cells treated with urine from those without stones and untreated controls. Transcript expression of shelterin components (TRF1, TRF2 and POT1) was decreased in HK-2 cells treated with H2O2, oxalate, COM, and urine from those with KS, in which case the expression was highest. Urine from those without KS did not significantly alter TRF1, TRF2, and POT1 mRNA expression in HK-2 cells relative to untreated controls. In conclusion, oxalate, COM, and urine from patients with CaOx KS induced SIPS and telomere shortening in renal tubular cells. SIPS induced by a lithogenic milieu may result from upregulation of p16 and downregulation of shelterin components, specifically POT1, and might contribute, at least in part, to the development of CaOx KS.

Project description:An indole-reacted calcium oxalate crystallization index (iCOCI) test was developed to quantify the total competence of urine to precipitate calcium oxalate (CaOx) crystals. We conducted the prospective cohort study in accordance with the STARD guideline to evaluate the accuracy of urinary iCOCI test (index test) for diagnosing urolithiasis. A total of 281 participants were recruited for the study. Levels of urinary iCOCI were determined in the pre-diagnostic 24-h urine samples. Positive urinary iCOCI (? 0.6 COM eqv., g/L) was accounted for 51% (144/281), and the rest of 49% (137/281) were negative. Non-contrast CT imaging (reference standard) was subsequently performed for the definite diagnosis of urolithiasis to divide the participants into two groups, non-stone subjects (NSS, n?=?122) and stone-forming subjects (SFS, n?=?159). It should be noted that only subjects who currently had urinary stone at the time of study were classified as SFS. Urinary iCOCI levels in the SFS were significantly higher than the NSS. ROC analysis revealed an area under curve (AUC) of 0.893 (95% CI: 0.855-0.932) in separating NSS from all SFS. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LH+) and negative likelihood ratio (LH-) of urinary iCOCI test for diagnosis of all urolithiasis were 87%, 80%, 84%, 84%, 83%, 4.44 and 0.16, respectively. Of 159 SFS, 38 were confirmed to have CaOx stones. Among these 38 CaOx SFS, only 2 had negative urinary iCOCI test. The AUC of urinary iCOCI test for separating CaOx SFS from NSS was markedly high (0.946, 95% CI: 0.914-0.978). Sensitivity, specificity, PPV, NPV, accuracy, LH+ and LH- of urinary iCOCI test for diagnosing CaOx urolithiasis were 95%, 86%, 68%, 98%, 88%, 6.80 and 0.06, respectively. Conclusion, we clinically validated that an innovative non-invasive urinary iCOCI test was highly accurate to diagnose urolithiasis, especially CaOx stone. With its high sensitivity and NPV, urinary iCOCI test is clinically intended to use as a screening test for CaOx urolithiasis. LH- of 0.06 indicates that negative result of urinary iCOCI test is highly accurate to rule out the CaOx stone formation. It is noted that urinary iCOCI level is expressed as arbitrary unit, and it is not directly related to the actual physiological level of urinary oxalate.

Dataset Information

Face-specific binding of prothrombin fragment 1 and human serum albumin to inorganic and urinary calcium oxalate monohydrate crystals.

Objective

Results

Conclusions

Publications

Face-specific binding of prothrombin fragment 1 and human serum albumin to inorganic and urinary calcium oxalate monohydrate crystals.

Similar Datasets

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