The family of kallikrein-related peptidases and kinin peptides as modulators of epidermal homeostasis.

The epidermis is the outermost skin layer and is part of one of the largest organs in the body; it is supported by the dermis, a network of fibrils, blood vessels, pilosebaceous units, sweat glands, nerves, and cells. The skin as a whole is a protective shield against numerous noxious agents, including microorganisms and chemical and physical factors. These functions rely on the activity of multiple growth factors, peptide hormones, proteases, and specific signaling pathways that are triggered by the activation of distinct types of receptors sited in the cell membranes of the various cell types present in the skin.

Autophagy is activated in human spermatozoa subjected to oxidative stress and its inhibition impairs sperm quality and promotes cell death.

Study Question: Does oxidative stress (OS) activate autophagy in human sperm?

Summary Answer: Human spermatozoa subjected to OS activate an autophagic response.

What Is Known Already: Autophagy is a regulated pathway of lysosomal degradation which helps eukaryotic cells to maintain or restore homeostasis, being a cellular stress response mechanism. OS is a main cause of impaired sperm function and is linked to male infertility; however, whether OS activates autophagy in human spermatozoa is unknown.

Kinin B1 Receptor Signaling in Skin Homeostasis and Wound Healing.

Kinins are proinflammatory peptides that are formed in the skin by the enzymatic action of tissue kallikrein (KLK1) on kininogens. Tissue kallikrein is produced by eccrine sweat glands and also by cells of the and other skin appendages. Kinin formation may be favored during inflammatory skin disorders when plasma constituents, including kininogens, extravasate from venules and capillaries, which have increased permeability in response to the plethora of inflammatory mediators generated in the course of acute inflammation.

Functional interrelationships between the kallikrein-related peptidases family and the classical kinin system in the human neutrophil.

In the human neutrophil, kallikrein-related peptidases (KLKs) have a significant functional relationship with the classical kinin system as a kinin B1 receptor agonist induces secretion of KLK1, KLK6, KLK10, KLK13 and KLK14 into the medium. Secretion of KLK1, the kinin-forming enzyme, may perpetuate formation of kinin in the inflammatory milieu by hydrolyzing extravasated kininogens present in tissue edema. Secretion of KLKs into the inflammatory milieu, induced by kinins or other proinflammatory mediators, provides the human neutrophil with a wide range of molecular interactions to hydrolyze different cellular and extracellular matrix components, which may be of critical relevance in different mechanisms involving inflammation.

Activation of the human keratinocyte B1 bradykinin receptor induces expression and secretion of metalloproteases 2 and 9 by transactivation of epidermal growth factor receptor.

The B1 bradykinin receptor (BDKRB1) is a component of the kinin cascade localized in the human skin. Some of the effects produced by stimulation of BDKRB1 depend on transactivation of epidermal growth factor receptor (EGFR), but the mechanisms involved in this process have not been clarified yet. The primary purpose of this study was to determine the effect of a BDKRB1 agonist on wound healing in a mouse model and the migration and secretion of metalloproteases 2 and 9 from human HaCaT keratinocytes and delineate the signalling pathways that triggered their secretion.

Intracellular signaling pathways involved in the release of IL-4 and VEGF from human keratinocytes by activation of kinin B1 receptor: functional relevance to angiogenesis.

The injured skin produces a number of mediators that directly or indirectly modulate cell chemotaxis, migration, proliferation, and angiogenesis. Components of the kinin pathway including the kinin B1 receptor (B1R) have been found to occur in the human skin, but information about its role on keratinocyte biology is still scarce. Our aim was to determine whether stimulation of B1R causes the secretion of IL-4 and/or VEGF from human keratinocytes and to evaluate the role of the B1R agonist Lys-des[Arg(9)]bradykinin and IL-4 on various stages of angiogenesis, such as cell migration, proliferation, and release of metalloproteases.

Expression and bioregulation of the kallikrein-related peptidases family in the human neutrophil.

The family of kallikrein-related peptidases (KLKs) has been identified in a variety of immunolabeled human tissue sections, but no previous study has experimentally confirmed their presence in the human neutrophil. We have investigated the expression and bioregulation of particular KLKs in the human neutrophil and, in addition, examined whether stimulation by a kinin B(1) receptor (B1R) agonist or fMet-Leu-Phe (fMLP) induces their secretion. Western blot analysis of neutrophil homogenates indicated that the MM of the KLKs ranged from 27 to 50 kDa.

Bioregulation of kallikrein-related peptidases 6, 10 and 11 by the kinin B₁ receptor in breast cancer cells.

The sera of patients with breast cancer have higher levels of des[Arg(9)]bradykinin, a kinin B1 receptor (B1R) agonist, than that from healthy individuals. Stimulation of breast cancer cells with the analog Lys-des[Arg(9)]bradykinin causes release of metalloproteinases-2 and -9 and increases cell proliferation. We examined the possibility that breast cancer cells, in addition to B1R, express the kinin-forming protease true tissue kallikrein (KLK1) and the endogenous proteins termed kininogens from which kinins are enzymatically released.

Kinin B1 receptor regulates interactions between neutrophils and endothelial cells by modulating the levels of Mac-1, LFA-1 and intercellular adhesion molecule-1.

Kinins are pro-inflammatory peptides that mimic the cardinal features of inflammation. We examined the concept that expression levels of endothelial intercellular adhesion molecule-1 (ICAM-1) and neutrophil integrins Mac-1 and LFA-1 are modulated by the kinin B1 receptor (B1R) agonist, Lys-des[Arg(9)]bradykinin (LDBK). Stimulation of endothelial cells with LDBK increased the levels of ICAM-1 mRNA transcripts/protein, and also of E-selectin and platelet endothelial adhesion molecule-1.

Expression of HER2 and bradykinin B₁ receptors in precursor lesions of gallbladder carcinoma.

Aim: To determine the expression of HER2 and bradykinin B(1) receptors (B(1)R) in the two pathogenic models of gallbladder cancer: the metaplasia-dysplasia-carcinoma and the adenoma-carcinoma pathways.

Methods: Receptor proteins were visualized by immunohistochemistry on 5-μm sections of paraffin-embedded tissue. Expression of both receptors was studied in biopsy samples from 92 patients (6 males and 86 females; age ranging from 28 to 86 years, mean 56 years).

Activation of kinin B1 receptor increases the release of metalloproteases-2 and -9 from both estrogen-sensitive and -insensitive breast cancer cells.

The kinin B(1) receptor (B(1)R) agonist Lys-des[Arg(9)]-bradykinin (LDBK) increases proliferation of estrogen-sensitive breast cancer cells by a process involving activation of the epidermal growth factor receptor (EGFR) and downstream signaling via the ERK1/2 mitogen-activated protein kinase pathway. Here, we investigated whether B(1)R stimulation induced release of the extracellular matrix metalloproteases MMP-2 and MMP-9 via ERK-dependent pathway in both estrogen-sensitive MCF-7 and -insensitive MDA-MB-231 breast cancer cells. Cells were stimulated with 1-100nM of the B(1)R agonist for variable time-points.

Kinin B1 receptor activation turns on exocytosis of matrix metalloprotease-9 and myeloperoxidase in human neutrophils: involvement of mitogen-activated protein kinase family.

During neutrophil activation and degranulation, MMP-9 and MPO are released into the extracellular space to propagate inflammatory disorders. As kinin peptides are major participants in acute inflammatory responses, and the G-protein-coupled B(1)R mediates the chemotaxis of human neutrophils, we examined the release of the neutrophil enzymes MMP-9 and MPO by the B(1)R agonist LDBK and determined the signaling pathways that may regulate this cellular effect. Cytochalasin-treated and -untreated neutrophils were suspended in HBSS and stimulated with a range concentration of LDBK for 5 min.

Stimulation of the bradykinin B(1) receptor induces the proliferation of estrogen-sensitive breast cancer cells and activates the ERK1/2 signaling pathway.

Kinin peptides exert multiple biological effects by binding to two types of G protein-coupled receptors known as B(1) (B(1)R) and B(2) receptors. Expression of the B(1)R in human breast cancer was recently reported, but up to now the consequences of its stimulation are unknown. Our aims were (1) to investigate the capacity of B(1)R to trigger cell proliferation in breast cancer cells, (2) to explore some of the downstream events occurring after B(1)R stimulation that may be linked to cell proliferation, and (3) to determine whether human breast tumors express potentially active B(1)R assessed by the binding of a radiolabeled agonist.

Kinin B2 receptor-coupled signal transduction in human cultured keratinocytes.

Kinins are key pro-inflammatory peptides that exhibit mitogenic effects in tissue-specific cellular systems. Since the life span of the keratinocyte is regulated by receptors that control proliferation and differentiation, and since both processes are affected during wound healing, we have examined the consequence of kinin B2 receptors (B2R) activation in cultured human keratinocytes. Stimulation of keratinocytes by Lys-bradykinin (LBK) induced a rapid and sustained phosphorylation of 42/44 mitogen-activated protein kinase (MAPK) that translocated to the nucleus, and decreased only after 120 min of stimulation.