Enhancement of lymphocyte proliferation by mouse glandular kallikrein

Deregulation of the Kallikrein Protease Family in the Salivary Glands of the Sjögren's Syndrome ERdj5 Knockout Mouse Model

Introduction

The purpose of this study was to identify differentially expressed proteins in salivary glands of the ERdj5 knockout mouse model for Sjögren's syndrome and to elucidate possible mechanisms for the morbid phenotype development. At the same time, we describe for the first time the sexual dimorphism of the murine submandibular salivary gland at the proteome level.

Methods

We performed Liquid Chromatography/Mass Spectrometry in salivary gland tissues from both sexes of ERdj5 knockout and 129SV wildtype mice. The resulting list of proteins was evaluated with bioinformatic analysis and selected proteins were validated by western blot and immunohistochemistry and further analyzed at the transcription level by qRT-PCR.

Results

We identified 88 deregulated proteins in females, and 55 in males in wildtype vs knockout comparisons. In both sexes, Kallikrein 1b22 was highly upregulated (fold change>25, ANOVA p<0.0001), while all other proteases of this family were either downregulated or not significantly affected by the genotype. Bioinformatic analysis revealed a possible connection with the downregulated NGF that was further validated by independent methods. Concurrently, we identified 416 proteins that were significantly different in the salivary gland proteome of wildtype female vs male mice and highlighted pathways that could be driving the strong female bias of the pathology.

Conclusion

Our research provides a list of novel targets and supports the involvement of an NGF-mediating proteolytic deregulation pathway as a focus point towards the better understanding of the underlying mechanism of Sjögren's syndrome.

Adenovirus-mediated kallikrein gene delivery reverses salt-induced renal injury in Dahl salt-sensitive rats

BACKGROUND

The tissue kallikrein-kinin system has been shown to play a role in cardiac and renal functions. In this study, we investigated the ability of kallikrein gene delivery to reverse salt-induced cardiac hypertrophy and renal injury in Dahl salt-sensitive rats.

METHODS

Adenovirus harboring the human tissue kallikrein gene, Ad.CMV-cHK, was delivered intravenously into Dahl salt-sensitive rats suffering from hypertension, cardiac hypertrophy and renal damage induced by a high salt diet (4% NaCl) for four weeks.

RESULTS

Expression of human kallikrein mRNA was detected in rat kidney, heart, aorta and liver, and immunoreactive human kallikrein levels were measured in the serum and urine of rats receiving gene delivery. A single injection of Ad.CMV-cHK caused a significant reduction of blood pressure for more than two weeks. Kallikrein gene transfer caused left ventricular mass reduction and elevated glomerular filtration rate, renal blood flow, urinary excretion, urinary kinin, nitrite/nitrate content, cGMP and cAMP levels. Morphological investigations showed that kallikrein gene transfer caused a significant reversal in salt-induced tissue and organ damage. In the heart, cardiac hypertrophy and fibrosis were reduced, and in the kidney, both glomerular sclerotic lesions and tubular damage were reversed.

CONCLUSIONS

Adenovirus-mediated kallikrein gene delivery is effective in reversing salt-induced cardiac hypertrophy and renal injury in Dahl-salt sensitive rats.

An IgE-binding TAME esterase in the urine of the mouse, Mus musculus domesticus

Among the highly heterogeneous components of the mouse urinary protein complex (MUP) a hydrolase was detected which was capable of spliting the proteinase ester substrate TAME as well as a synthetic chromogenic tripeptide specific for tissue and urinary kallikreins. The binding of mouse-specific IgE antibodies from the serum of a highly mouse-allergic patient occurred preferentially to this kallikrein-like enzyme. This finding underscores the possible association of significant biological activities with predominant IgE-binding allergens, especially in view of the strongly sensitizing potential and the known messenger functions of the MUP proteins.