Previous proteomic and transcriptional analyses of multiple sclerosis lesions1, 2, 3 revealed modulation of the renin-angiotensin and the opposing kallikrein-kinin pathways. Here we identify kinin receptor B1 (Bdkrb1) as a specific modulator of immune cell entry into the central nervous system (CNS). We demonstrate that the Bdkrb1 agonist R838 (Sar-[d-Phe]des-Arg9-bradykinin) markedly decreases the clinical symptoms of experimental autoimmune encephalomyelitis (EAE) in SJL mice4, 5, 6, whereas the Bdkrb1 antagonist R715 (Ac-Lys-[d-βNal7, Ile8]des-Arg9-bradykinin) resulted in earlier onset and greater severity of the disease. Bdkrb1-deficient (Bdkrb1−/−) C57BL/6 mice7 immunized with a myelin oligodendrocyte glycoprotein fragment, MOG35–55, showed more severe disease with enhanced CNS-immune cell infiltration. The same held true for mixed bone marrow–chimeric mice reconstituted with Bdkrb1−/− T lymphocytes, which showed enhanced T helper type 17 (TH17) cell invasion into the CNS. Pharmacological modulation of Bdkrb1 revealed that in vitro migration of human TH17 lymphocytes across blood-brain barrier endothelium is regulated by this receptor. Taken together, these results suggest that the kallikrein-kinin system is involved in the regulation of CNS inflammation, limiting encephalitogenic T lymphocyte infiltration into the CNS, and provide evidence that Bdkrb1 could be a new target for the treatment of chronic inflammatory diseases such as multiple sclerosis.

Background:Neurolysin is known to cleave several bioactive peptides in vitro. Results: Neurolysin knock-out mice showed increased glucose tolerance, insulin sensitivity, and gluconeogenesis, which likely relates to increased expression of both specific liver mRNAs and intracellular peptides. Conclusion: Neurolysin plays a role in energy metabolism. Significance: Neurolysin could be used as a therapeutic target to counteract insulin resistance.The oligopeptidase neurolysin (EC 3.4.24.16; Nln) was first identified in rat brain synaptic membranes and shown to ubiquitously participate in the catabolism of bioactive peptides such as neurotensin and bradykinin. Recently, it was suggested that Nln reduction could improve insulin sensitivity. Here, we have shown that Nln KO mice have increased glucose tolerance, insulin sensitivity, and gluconeogenesis. KO mice have increased liver mRNA for several genes related to gluconeogenesis. Isotopic label semiquantitative peptidomic analysis suggests an increase in specific intracellular peptides in gastrocnemius and epididymal adipose tissue, which likely is involved with the increased glucose tolerance and insulin sensitivity in the KO mice. These results suggest the exciting new possibility that Nln is a key enzyme for energy metabolism and could be a novel therapeutic target to improve glucose uptake and insulin sensitivity.

Rationale: Positive outward remodeling of pre-existing collateral arteries into functional conductance arteries, arteriogenesis, is a major endogenous rescue mechanism to prevent cardiovascular ischemia. Collateral arterial growth is accompanied by expression of kinin precursor. However, the role of kinin signaling via the kinin receptors (B1R and B2R) in arteriogenesis is unclear.Objective: The purpose of this study was to elucidate the functional role and mechanism of bradykinin receptor signaling in arteriogenesis. Key Words: bone marrow transplantation Ⅲ bradykinin receptors Ⅲ collateral growth Ⅲ leukocytes A rteriogenesis is the process that involves the flow-induced outward remodeling of preexisting collateral arterial pathways into functional conductance arteries (biological bypass). As a result of the arteriogenesis process, blood perfusion to the compromised region is restored; 1 therefore, it is regarded as a clinically highly relevant target. It is established that arteriogenesis is triggered by changes in local hemodynamic conditions and subsequent activation of inflammatory pathways. We previously showed that expression of kininogen, a precursor of the vasoactive kinin peptides, was selectively expressed in growing collaterals of the rat brain. 2 Here we investigated the role of kinin signaling in bradykinin receptor-deficient mice for collateral growth and evaluated whether stimulation with bradykinin receptor antagonists/agonists may modulate arteriogenesis in mice and rats. Our data suggest that the kinin-receptor signaling pathway may act as a molecular link between changes in hemodynamic forces (artery occlusion) and the activation of inflammatory pathways, including attraction of bone marrow Original Methods and Results:

Background: Angiotensin II, the renin-angiotensin system effector peptide, interacts with a recently discovered binding site that is distinctly different from its classic receptors. Results: A radioiodinated angiotensin II photoprobe bound to a ϳ75-kDa membrane protein, enabling its isolation and identification. Conclusion: Membrane-bound metalloendopeptidase neurolysin (EC 3.4.24.16) is the novel angiotensin-binding protein.Significance: This metalloendopeptidase may be a crucial component of the renin-angiotensin system.

Prolylcarboxypeptidase (PRCP) converts AngII to Ang (1-7) but only at an acidic pH. Global PRCP deficiency causes heart and kidney alterations and a moderate rise in BP. PRCP is abundant in the kidney collecting tubules, where the prevailing pH is low. In collecting tubules, PRCP deficiency could result in impaired AngII degradation. Increased AngII at this nephron site stimulates Na reabsorption and increases BP.

BackgroundKinins participate in the pathophysiology of obesity and type 2 diabetes by mechanisms which are not fully understood. Kinin B1 receptor knockout mice (B1 −/−) are leaner and exhibit improved insulin sensitivity.Methodology/Principal FindingsHere we show that kinin B1 receptors in adipocytes play a role in controlling whole body insulin action and glucose homeostasis. Adipocytes isolated from mouse white adipose tissue (WAT) constitutively express kinin B1 receptors. In these cells, treatment with the B1 receptor agonist des-Arg9-bradykinin improved insulin signaling, GLUT4 translocation, and glucose uptake. Adipocytes from B1 −/− mice showed reduced GLUT4 expression and impaired glucose uptake at both basal and insulin-stimulated states. To investigate the consequences of these phenomena to whole body metabolism, we generated mice where the expression of the kinin B1 receptor was limited to cells of the adipose tissue (aP2-B1/B1 −/−). Similarly to B1 −/− mice, aP2-B1/B1 −/− mice were leaner than wild type controls. However, exclusive expression of the kinin B1 receptor in adipose tissue completely rescued the improved systemic insulin sensitivity phenotype of B1 −/− mice. Adipose tissue gene expression analysis also revealed that genes involved in insulin signaling were significantly affected by the presence of the kinin B1 receptor in adipose tissue. In agreement, GLUT4 expression and glucose uptake were increased in fat tissue of aP2-B1/B1 −/− when compared to B1 −/− mice. When subjected to high fat diet, aP2-B1/B1 −/− mice gained more weight than B1 −/− littermates, becoming as obese as the wild types.Conclusions/SignificanceThus, kinin B1 receptor participates in the modulation of insulin action in adipocytes, contributing to systemic insulin sensitivity and predisposition to obesity.

Fusarium proliferatum (teleomorph: Gibberella intermedia) is a causal agent of crown rot of Asparagus officinalis and is one potential fumonisin-producing species within the genus Fusarium. It colonizes roots and crowns of asparagus plants, but could also be isolated from symptomless asparagus spears. Fusarium proliferatum isolates obtained from perennial asparagus plantings from Austria and Germany were included in a study on detectability and variability of two essential genes of the fumonisin-gene cluster. Genetic fingerprinting of 45 isolates revealed 14 different fingerprint groups, indicating genetic heterogenicity of F. proliferatum. Most isolates differentiated into three main fingerprint clusters, but no association was found between fingerprint group and origin of the isolates. By gene-specific PCR it was shown that, in 25 isolates tested, both initial genes of the fumonisin biosynthetic pathway -FUM1, encoding a polyketide synthase and FUM8, a gene for a putative aminoacyl transferase -were detectable. This suggests that these isolates were able to produce fumonisins and could contribute to the detected contamination in originating asparagus spears with this mycotoxin. Thus, early detection of FUM-genes in F. proliferatum-colonized asparagus may be suited to prevent uptake of fumonisin contaminated food with the human diet. Restriction fragment length polymorphism analysis (PCR-RFLP) of the amplified FUM gene fragments revealed little sequence variability, suggesting a conserved structure of these genes within this species. However, sequence analysis confirmed intraspecific nucleotide polymorphisms of these genes.

The Kallikrein-Kinin System (KKS) has been implicated in several aspects of metabolism, including the regulation of glucose homeostasis and adiposity. Kinins and des-Arg-kinins are the major effectors of this system and promote their effects by binding to two different receptors, the kinin B2 and B1 receptors, respectively. To understand the influence of the KKS on the pathophysiology of obesity and type 2 diabetes (T2DM), we generated an animal model deficient for both kinin receptor genes and leptin (obB1B2KO). Six-month-old obB1B2KO mice showed increased blood glucose levels. Isolated islets of the transgenic animals were more responsive to glucose stimulation releasing greater amounts of insulin, mainly in 3-month-old mice, which was corroborated by elevated serum C-peptide concentrations. Furthermore, they presented hepatomegaly, pronounced steatosis, and increased levels of circulating transaminases. This mouse also demonstrated exacerbated gluconeogenesis during the pyruvate challenge test. The hepatic abnormalities were accompanied by changes in the gene expression of factors linked to glucose and lipid metabolisms in the liver. Thus, we conclude that kinin receptors are important for modulation of insulin secretion and for the preservation of normal glucose levels and hepatic functions in obese mice, suggesting a protective role of the KKS regarding complications associated with obesity and T2DM.