Cellular localization of kallistatin and tissue kallikrein in human pancreas and salivary glands

Evaluation of preterm infants having bronchopulmonary dysplasia with echocardiography and serum biomarkers

BACKGROUND AND OBJECTIVES

Pulmonary hypertension is frequent in infants with bronchopulmonary dysplasia. Echocardiography is easy to perform, non-invasive, and recommended by guidelines even though solely it is not enough. Catheterisation is gold standard but invasive, expensive, and not cost effective. Therefore, we aimed to assess to find out the role of biomarkers besides echocardiography in the diagnosis of pulmonary hypertension in preterm with bronchopulmonary dysplasia.

METHODS

This study is done during the time period January 2016-2017. The diagnosis of pulmonary hypertension was assessed by echocardiography at 36 weeks later repeated at 3rd and 6th months. We also repeated biomarkers at 3rd and 6th months. The infants born ≤ 28 weeks in Erciyes University hospital who were diagnosed bronchopulmonary dysplasia were included. Infants with genetic syndromes, structural lung, and CHDs were excluded. Patients without bronchopulmonary dysplasia but having pulmonary hypertension due to other reasons and patients having echocardiograms without adequate images were excluded.

RESULTS

At initial, 21/59 patients had bronchopulmonary dysplasia-pulmonary hypertension (Group 1), 21/59 had no bronchopulmonary dysplasia-pulmonary hypertension (Group 2), and 17/59 had bronchopulmonary dysplasia without pulmonary hypertension (Group 3). Systolic pulmonary artery pressure and pulmonary vascular resistance were found high in Group 1 (36 mmHg; p <0.001, 1.25 Woods Unit; p < 0.0017, respectively). Tricuspid annular plane systolic excursion values of Group 1 were low. Median serum kallistatin levels of Group 1 were lower than the other groups (230.5 (114.5-300.5) µg/ml; p < 0.005). During the study period, pulmonary hypertension of 14/21 bronchopulmonary dysplasia-pulmonary hypertension resolved, six patients in Group 3 developed pulmonary hypertension. However, there was no difference in the biomarkers of these six patients.

CONCLUSION

In the diagnosis and the follow-up of pulmonary hypertension in bronchopulmonary dysplasia patients, besides echocardiography kallistatin, gelsolin, NT-probrain natriuretic peptide, homocysteine, and cystatin-C levels can be used. Further studies were required with large sample sizes.

Quantitative proteomic analysis of pancreatic cyst fluid proteins associated with malignancy in intraductal papillary mucinous neoplasms

Background

The application of advanced imaging technologies for identifying pancreatic cysts has become widespread. However, accurately differentiating between low-grade dysplasia (LGD), high-grade dysplasia (HGD), and invasive intraductal papillary mucinous neoplasms (IPMNs) remains a diagnostic challenge with current biomarkers, necessitating the development of novel biomarkers that can distinguish IPMN malignancy.

Methods

Cyst fluid samples were collected from nine IPMN patients (3 LGD, 3 HGD, and 3 invasive IPMN) during their pancreatectomies. An integrated proteomics approach that combines filter-aided sample preparation, stage tip-based high-pH fractionation, and high-resolution MS was applied to acquire in-depth proteomic data of pancreatic cyst fluid and discover marker candidates for IPMN malignancy. Biological processes of differentially expressed proteins that are related to pancreatic cysts and aggressive malignancy were analyzed using bioinformatics tools such as gene ontology analysis and Ingenuity pathway analysis. In order to confirm the validity of the marker candidates, 19 cyst fluid samples were analyzed by western blot.

Results

A dataset of 2992 proteins was constructed from pancreatic cyst fluid samples. A subsequent analysis found 2963 identified proteins in individual samples, 2837 of which were quantifiable. Differentially expressed proteins between histological grades of IPMN were associated with pancreatic diseases and malignancy according to ingenuity pathway analysis. Eighteen biomarker candidates that were differentially expressed across IPMN histological grades were discovered—7 DEPs that were upregulated and 11 that were downregulated in more malignant grades. HOOK1 and PTPN6 were validated by western blot in an independent cohort, the results of which were consistent with our proteomic data.

Conclusions

This study demonstrates that novel biomarker candidates for IPMN malignancy can be discovered through proteomic analysis of pancreatic cyst fluid.

Electronic supplementary material

The online version of this article (10.1186/s12014-018-9193-1) contains supplementary material, which is available to authorized users.

Kallistatin, a new and reliable biomarker for the diagnosis of liver cirrhosis

Kallistatin, which protects organs and cells against inflammation, fibrosis and oxidative stress, is mainly synthesized and secreted in liver. However, its relationship to human liver disease remains unclear. The purpose of this study was to explore the relationship between serum kallistatin and clinical evidence of both cirrhosis and hepatocellular carcinoma (HCC), and to determine if serum kallistatin levels could be used as a diagnostic indicator of hepatic health status, especially human liver cirrhosis (LC). Our cohort consisted of 115 patients with clinically proven liver fibrosis (LF), LC, or HCC by liver biopsies, and 31 healthy controls (CON). Serum kallistatin levels were quantified by ELISA. Results of the present study demonstrated that irrespective of the underlying etiology, serum kallistatin levels were significantly lower in the LF/LC group when compared with the CON group. A decrease in serum kallistatin levels appeared to reflect the extent of cirrhosis, with the lowest levels associated with higher grades of cirrhosis. Patients with LC had a noticeable correlation between serum kallistatin levels and other serum biochemical indicators. The area under the curve (AUC) for LC, viral liver cirrhosis (VLC) and alcoholic liver cirrhosis (ALC) was 0.845, 0.757 and 0.931, respectively. In conclusion, our findings demonstrated that kallistatin, a plasma protein produced by the liver, can be a useful and reliable diagnostic indicator of hepatic health status, especially for LC.

Plasma kallistatin is associated with adiposity and cardiometabolic risk in apparently healthy African American adolescents

OBJECTIVE

It is generally recognized that obesity and cardiometabolic risk are more prevalent in African Americans. Kallistatin, a novel tissue kallikrein inhibitor, has anti-inflammatory and anti-oxidant properties. Thus, the goal of this study was to examine the relationships among plasma kallistatin levels, adiposity and cardiometabolic risk factors in African American adolescents.

MATERIALS/METHODS

Plasma kallistatin levels were determined in 318 apparently healthy African American adolescents (aged 14-19 years, 48.1% females) by enzyme-linked immunosorbent assay.

RESULTS

Plasma kallistatin levels did not differ between males (27.9±11.2 μg/mL) and females (26.8±11.0 μg/mL) (p=0.47). Plasma kallistatin levels were inversely correlated with percent body fat (% BF, r=-0.13, p=0.04), total cholesterol (r=-0.28, p<0.01), low density lipoprotein cholesterol (LDL, r=-0.30, p<0.01) and interleukin-6 (r=-0.14, p=0.05), but positively correlated with adiponectin (r=0.16, p=0.03) and high density lipoprotein (HDL, r=0.17, p=0.02). These correlations remained significant after adjustment for age, sex and body mass index percentiles. Stepwise multiple linear regression analysis showed that LDL cholesterol alone explained 14.2% of the variance in kallistatin, while % BF and adiponectin explained an additional 3.6% and 2.8% of the variance, respectively.

CONCLUSIONS

The present study demonstrates that plasma kallistatin levels are inversely associated with adiposity, adverse lipid profiles and inflammation in apparently healthy African American adolescents. As a potent antioxidant and anti-inflammation agent, kallistatin may also hold therapeutic promise in cardiometabolic disorders.

Intestinal tissue kallikrein-kinin system in inflammatory bowel disease

Tissue kallikrein cleaves kininogens to release kinins. Kinins mediate inflammation by activating constitutive bradykinin receptor-2 (BR2), which are rapidly desensitized, and induced by inflammatory cytokines bradykinin receptor-1 (BR1), resistant to desensitization. Intestinal tissue kallikrein (ITK) may hydrolyze growth factors and peptides, whereas kinins are responsible for capillary permeability, pain, synthesis of cytokines, and adhesion molecule-neutrophil cascade. Our and others results have demonstrated ITK in intestinal goblet cells and its release into interstitial space during inflammation. Kallistatin, an inhibitor of ITK, has been shown in epithelial and goblet cells, and was decreased in inflamed intestine as well as in plasma compared with noninflammatory controls. BR1 was upregulated in patients with inflammatory bowel disease (IBD), and it has expressed in an apical part of enterocytes in inflamed intestine, but in the basal part in normal intestine. ITK and BR1 were visualized in macrophages forming granuloma in Crohn's disease. In animal studies BR2 blockade decreased intestinal contraction, but had limited effect on inflammatory lesions. BR1 was found to be upregulated in animal inflamed intestine, in part dependent on tumor necrosis factor alpha (TNF-α). A selective BR1 receptor antagonist decreased morphological and biochemical features of experimental intestinal inflammation. Both BR1 and BR2 mediate epithelial ion transport that leads to secretory diarrhea. The upregulation of BR1 in inflamed intestine provides a structural basis for the kinins function, suggesting that a selective BR1 antagonist may have potential in therapeutic trial of IBD patients.

Kallistatin inhibits vascular inflammation by antagonizing tumor necrosis factor-alpha-induced nuclear factor kappaB activation

Kallistatin is a plasma protein with anti-inflammatory properties. In this study, we investigated the role and mechanisms of kallistatin in inhibiting endothelial inflammation through its heparin-binding domain. We showed that recombinant wild-type kallistatin dose-dependently competed with tumor necrosis factor (TNF)-alpha binding to TNF-alpha receptor in endothelial cells, whereas kallistatin mutant at the heparin-binding domain had no effect. Kallistatin, but not kallistatin mutant at the heparin-binding domain, abrogated TNF-alpha-induced endothelial cell activation, as evidenced by inhibition of TNF receptor 1-associated death domain protein activation, inhibitor of nuclear factor kappaB-alpha degradation, nuclear factor kappaB translocation, and p38 mitogen-activated protein kinase phosphorylation, as well as cell adhesion molecule and cytokine expression. Moreover, kallistatin, but not kallistatin mutant at the heparin-binding domain, inhibited TNF-alpha-induced human monocytic THP-1 cell adhesion to endothelial cells and prevented vascular endothelial growth factor-induced endothelial permeability. In mice, kallistatin gene delivery prevented vascular leakage provoked by complement factor C5a, whereas delivery of kallistatin heparin mutant gene had no effect. Similarly, gene transfer of kallistatin, but not the kallistatin heparin mutant, inhibited collagen/adjuvant-induced arthritis in rats. These results indicate that kallistatin's heparin-binding site plays an essential role in preventing TNF-alpha-mediated endothelial activation and reducing vascular endothelial growth factor-induced vascular permeability, resulting in attenuation of vascular inflammation in cultured endothelial cells and animal models. This study identifies a protective role of kallistatin in vascular injury, thereby implicating the therapeutic potential of kallistatin for vascular and inflammatory diseases.

Salutary Effect of Kallistatin in Salt-Induced Renal Injury, Inflammation, and Fibrosis via Antioxidative Stress

An inverse relationship exists between kallistatin levels and salt-induced oxidative stress in Dahl-salt sensitive rats. We further investigated the role of kallistatin in inhibiting inflammation and fibrosis through antioxidative stress in Dahl-salt sensitive rats and cultured renal cells. High-salt intake in Dahl-salt sensitive rats induced elevation of thiobarbituric acid reactive substances (an indicator of lipid peroxidation), malondialdehyde levels, reduced nicotinamide-adenine dinucleotide phosphate oxidase activity, and superoxide formation, whereas kallistatin gene delivery significantly reduced these oxidative stress parameters. Kallistatin treatment improved renal function and reduced kidney damage as evidenced by diminished proteinuria and serum urea nitrogen levels, glomerular sclerosis, tubular damage, and protein cast formation. Kallistatin significantly decreased interstitial monocyte-macrophage infiltration and the expression of tumor necrosis factor-α, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1. Kallistain also reduced collagen fraction volume and the deposition and expression of collagen types I and III. Renal protection by kallistatin was associated with increased NO levels and endothelial NO synthase expression and decreased p38 mitogen-activated protein kinase, extracellular signal-regulated kinase phosphorylation, and transforming growth factor-β1 expression. Moreover, kallistatin attenuated tumor necrosis factor-α–induced intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression via inhibition of reactive oxygen species formation and p38 mitogen-activated protein kinase and nuclear factor-κB activation in cultured proximal tubular cells. Kallistatin inhibited fibronectin and collagen expression by suppressing angiotensin II–induced reactive oxygen species generation and transforming growth factor-β1 expression in cultured mesangial cells. These combined findings reveal that kallistatin is a novel antioxidant, which prevents salt-induced kidney injury, inflammation, and fibrosis by inhibiting reactive oxygen species–induced proinflammatory cytokine and transforming growth factor-β1 expression.

Distribution of 15 Human Kallikreins in Tissues and Biological Fluids

Background: Kallikreins (KLKs) are a group of 15 secreted serine proteases. Some KLKs are established or candidate cancer biomarkers, but for most the physiological function is unknown. We characterized the protein and mRNA abundance patterns of all 15 KLKs in multiple panels of human tissues and biological fluids.

Methods: We used sensitive and specific sandwich-type ELISAs for each KLK. Reverse transcription PCR was used for transcript amplification. Multiple panels of human tissue extracts (adult and fetal) were tested, along with various biological fluids.

Results: Quantitative protein expression data on 7 sets of adult and 3 sets of fetal tissues were collected for all 15 KLKs. KLKs were also quantified in the following biological fluids: seminal plasma, breast milk, follicular fluid, breast cyst fluid, breast cancer cytosol, amniotic fluid, ovarian cancer ascites, cerebrospinal fluid, cervicovaginal fluid, and urine. The data were used to generate heat maps of KLK concentrations in tissues and fluids and categorize KLK abundance as highly restricted (KLK2 and KLK3 in prostate), restricted (KLK5 in skin, salivary gland, breast, and esophagus; KLK6 in brain and central nervous system; KLK7 in esophagus, heart, liver, and skin; KLK8 in breast, esophagus, skin, and tonsil; KLK13 in esophagus and tonsil), or wide (KLKs 1, 4, 9, 10, 11, 12, 14, and 15).

Conclusions: Quantitative KLK concentrations in tissues and fluids aid in the elucidation of KLK function, and coexpression patterns provide clues for KLK participation in proteolytic cascades.

Distribution of kallikrein in striated duct cells of monkey submandibular glands

Although kallikrein has been localised in the striated duct cells of salivary glands, the manner in which it enters the saliva remains unclear. Here, immunocytochemistry was used at both the light- and electron-microscopic levels to localise kallikrein antigenicity. At the light-microscopic level, kallikrein was found at the apices of some, but not all duct cells. At the electron-microscopic level, it was found in small granules situated between the apical vacuoles and the luminal membrane. The kallikrein-containing granules underwent exocytosis at the cell apex.

A synthetic tissue kallikrein inhibitor suppresses cancer cell invasiveness

Serine proteinases modulate the interaction of tumor cells with extracellular matrix components during extravasation and metastasis. The serine proteinase tissue kallikrein has been previously demonstrated in several human adenocarcinomas, and we presently report the localization of immunoreactive kallikrein and its mRNA in pancreatic adenocarcinoma. In addition, a synthetic peptide-based inhibitor specific for tissue kallikrein (FE999024) was used in our studies to explore a possible role for kallikrein in cancer cell invasiveness. Matrigel invasion assays were performed with a human breast-cancer cell line, MDA-MB-231, which expresses tissue kallikrein in culture. In the presence of FE999024 invasion through Matrigel was inhibited in a dose-dependent manner to a maximum of 39%. We also developed a novel ex vivo assay in which breast cancer cells are infused into the pulmonary circulation of artificially ventilated explanted rat lungs. At intervals up to 6 hours after infusion pulmonary invasion was quantified by bronchial alveolar lavage to recover human cancer cells from the airspace. Invading cells in the lung interstitium were also quantified after immunohistochemistry with a monoclonal antibody specific for human cytokeratin 18. The synthetic kallikrein inhibitor attenuates breast cancer cell invasion into the airspace by 33% when quantified by lavage recovery and up to 34% as quantified in the lung interstitium by cytokeratin 18 immunostaining. Our results indicate tissue kallikrein may participate in the invasion and metastasis of human adenocarcinomas. The newly developed explanted rodent lung assay should be useful for the study of cancer cells, neutrophils, or other extravasating cells.

Secretion by striated ducts of mammalian major salivary glands: review from an ultrastructural, functional, and evolutionary perspective

In addition to their role in electrolyte homeostasis, striated ducts (SDs) in the major salivary glands of many mammalian species engage in secretion of organic products. This phenomenon usually is manifested as the presence of small serous-like secretory granules in the apical cytoplasm of SD cells. The composition of these granules is largely unknown, except in the case of the cat and rat submandibular gland, where the granules have unequivocally been shown to contain kallikrein. In some species, the apical cytoplasm of SD cells contains variable numbers of vesicles, both spherical and elongated, that vary in appearance from 'empty' to moderately dense. In the rat parotid gland, lucent vesicles transport glycoproteins to the luminal surface where they are incorporated into the apical plasmalemma and the glycocalyx. There is a strong possibility that in various species some of these vesicles are involved in transcytosis of antibodies to the saliva from their source (plasma cells) in the surrounding connective tissue. In addition, vesicles may engage in transfer of growth factors from the saliva to the interstitium. In a few species, conventional SDs have been replaced by ducts that are wholly given over to secretion, i.e., they entirely lack basal striations; although such ducts occupy the histological position of conventional SDs, it is not clear whether they represent a new type of duct or merely are modifications of SDs. Broad-based comparisons of ultrastructural and other data about SDs offer some insight into evolutionary history of salivary glands and their role in the adaptive radiation of mammals. Evolutionary patterns emerged when we made interspecific comparisons across mammalian orders. Among the bats, there is a clear relationship between SD secretion and general categories of diet.

Subcellular localization of epidermal growth factor in human parotid gland

The intracellular distribution of epidermal growth factor was investigated in human parotid gland by immunogold cytochemistry at the electron-microscopy level. Epidermal growth factor immunoreactivity was demonstrated in both acini and ducts. In acinar cells, secretory granules appeared moderately stained, clearly indicating that parotid gland contributes to salivary epidermal growth factor through granule exocytosis. In ductal cells, gold particles were found to decorate numerous cytoplasmic vesicles, particularly abundant in striated duct cells. Since epidermal growth factor reactive vesicles were seen not only at the cellular apex, but nearby lateral plasma membranes as well, it leads to the hypothesis that epidermal growth factor may be discharged both apically into the saliva, and basally into the interstitium.

Novel roles of kallistatin, a specific tissue kallikrein inhibitor, in vascular remodeling

We have purified, cloned and characterized kallistatin, a tissue kallikrein-binding protein (KBP) in humans and rodents. Kallistatin is a unique serine proteinase inhibitor (serpin) with Phe-Phe residues at the P2 and P1 positions. Structural and functional analysis of kallistatin by site-directed mutagenesis and protein engineering indicate that wild-type kallistatin is selective for tissue kallikrein. Kallistatin is expressed and localized in endothelial and smooth muscle cells of blood vessels and has multiple roles in vascular function independent of the tissue kallikrein-kinin system. First, kallistatin induces vasorelaxation of isolated aortic rings and reduces renal perfusion pressure in isolated rat kidneys. Transgenic mice overexpressing rat kallistatin are hypotensive, and adenovirus-mediated gene delivery of human kallistatin attenuates blood pressure rise in spontaneously hypertensive rats. Second, kallistatin stimulates the proliferation and migration of vascular smooth muscle cells in vitro and neointima formation in balloon-injured rat arteries. Third, kallistatin inhibits the proliferation, migration and adhesion of endothelial cells in vitro and angiogenesis in the rat model of hindlimb ischemia. These results demonstrate novel roles of kallistatin in blood pressure regulation and vascular remodeling.

Detection of tissue kallikrein and kinin B1 and B2 receptor mRNAs in human brain by in situ RT-PCR

Tissue kallikrein (TK) and kinin receptors have been immuno-localized in various areas of the human nervous system, suggesting that the kallikrein-kinin system (KKS) may be functionally active in the brain. The aim of this study was to determine the cellular expression of TK and kinin B1 and B2 receptor mRNAs in specific regions of the human brain by in situ reverse transcriptase polymerase chain reaction. Autopsy samples of the brain, spinal cord, kidney and salivary gland were embedded in paraffin. Sections (5 microm), adhered onto silane coated glass slides, were treated with Proteinase K and DNase, followed by reverse transcription polymerase chain reaction with specific KKS primers and digoxigenin-dUTP. Detection of the digoxigenin-label demonstrated localization of TK, B1 and B2 mRNAs in the cytoplasm of some neuronal cell bodies in the hypothalamus, thalamus, frontal cortex and spinal cord. TK mRNA was also observed in the ependymal cells lining the cerebral ventricles and epithelial cells of the choroid plexus. In the choroid plexus, only B1 gene expression was observed in some choroidal epithelial cells while no B2 labeling was detected. The identification of mRNAs to TK, B1 and B2 kinin receptors in human nervous tissue supports previous evidence for the presence of the KKS in the brain and confirms localized protein synthesis.