Cathepsin K and schizophrenia.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Uwe Lendeckel
Publications and source records attributed to Uwe Lendeckel.
Triggering endogenous immunosuppressive mechanisms by combined targeting of Dipeptidyl peptidase IV (DPIV/CD26) and Aminopeptidase N (APN/ CD13)--a novel approach for the treatment of inflammatory bowel disease.
The ectopeptidases Dipeptidylpeptidase IV and Alanyl-Aminopeptidase N, strongly expressed by both, activated and regulatory T cells were shown to co-operate in T cell regulation. Based on the findings that DPIV and APN inhibitors induce the TGF-beta1 and IL-10 production and a suppression of T helper cell proliferation in parallel, and that particularly APN inhibitors amplify the suppressing activity of regulatory T cells, both peptidases represent a promising target complex for treatment of diseases associated with an imbalanced T cell response, such as inflammatory bowel diseases (IBD). The aim of the present study was to analyze the therapeutic potential of DPIV and APN inhibitors in vivo in a mouse model of colitis. Balb/c mice received 3% (w/v) dextran sulphate sodium with the drinking water for 7 days. After onset of colitis symptoms, inhibitor treatment started at day 3. Disease activity index (DAI) was assessed daily, supplemented by histological and immunological analysis. While the DPIV inhibitor Lys-[Z(NO])(2)]-pyrrolidide or the APN-inhibitor Actinonin alone had marked but no significant therapeutic effects, the simultaneous administration of both inhibitors reduced colitis activity in comparison to placebo treated mice, significantly (DAI 4.8 vs. 7.7, p<0.005). A newly developed compound IP12.C6 with inhibitory capacity toward both enzymes significantly attenuated the clinical manifestation of colitis (DAI 3.2 vs. 7.6, p<0.0001). TGF-beta mRNA was found to be up-regulated in colon tissue of inhibitor-treated animals. In summary our results strongly suggest that combined DPIV and APN inhibition by synthetic inhibitors represents a novel and efficient approach for the pharmacological therapy of IBD by triggering endogenous immunosuppressive mechanisms.
Animals↗
Dipeptidyl peptidase IV (DP IV, CD26) and aminopeptidase N (APN, CD13) as regulators of T cell function and targets of immunotherapy in CNS inflammation.
The ectoenzymes dipeptidyl peptidase IV (DP IV, CD26) and aminopeptidase N (APN, CD13) have been implicated in the regulation of T cell activation and function. Both DP IV and APN serve as targets of efficient enzymatic inhibitors which induce autocrine production of TGF-beta1 and subsequent suppression of T cell proliferation and cytokine release. Here, we tested the hypothesis that the simultaneous inhibition of DP IV and APN enzymatic activity on leukocytes potentiates the anti-inflammatory effect of single DP IV or APN inhibitors. Our data show that the combined application of DP IV and APN inhibitors increased suppression of DNA synthesis in human peripheral blood mononuclear cells and isolated T cells in vitro when compared to the use of a single ectopeptidase inhibitor. Moreover, the combined action of DP IV and APN inhibitors markedly increased TGF-beta1 production associated with the observed immunosuppressive effects. In vivo, targeting DP IV and APN provided a potent therapeutic approach for the treatment of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. Taken together, our study suggests that combined DP IV and APN inhibition on pathogenic T cells represents a novel and efficient therapy for autoimmune disease of the central nervous system by a mechanism that involves an active TGF-beta1-mediated anti-inflammatory effect at the site of pathology.
Animals↗
Interferon-gamma down-regulates transcription of the mu-opioid receptor gene in neuronal and immune cells.
Earlier investigations demonstrated up-regulated mu-opioid receptor expression in neuronal and immune cells in response to IL-1, IL-4, IL-6 and TNF-alpha. We herein report that mu-opioid receptor expression is down-regulated in SH SY5Y neuroblastoma cells by IFN-gamma, and that IL-4-mediated induction of mu-opioid receptor expression is inhibited in Jurkat T cells by IFN-gamma. Additionally, mu-opioid receptor transcripts were found in IL-4-expressing human primary T helper cells type 2, but not in type 1 cells, which typically express IFN-gamma. This indicates that mu-opioid receptor expression may be altered under conditions like inflammation, viral infections or neurological diseases associated with imbalanced cytokine expression.
Down-Regulation↗
Attractin, a dipeptidyl peptidase IV/CD26-like enzyme, is expressed on human peripheral blood monocytes and potentially influences monocyte function.
The ectoenzyme dipeptidyl peptidase IV (DP IV; CD26) was shown to play a crucial role in T cell activation. Several compounds inhibiting DP IV-like activity are currently under investigation for the treatment of Type 2 diabetes, rheumatoid arthritis, colitis ulcerosa, psoriasis, multiple sclerosis, and other diseases. In the present study, we show that human peripheral blood monocytes express a DP IV-like enzyme activity, which could be inhibited completely by the synthetic DP IV inhibitor Lys[Z(NO(2))]-thiazolidide. DP IV immunoreactivity was not detectable on monocytes, and DP IV transcript levels of monocytes were near the detection limit of quantitative polymerase chain reaction. However, monocytes exhibit a strong mRNA expression of the multifunctional DP IV-like ectoenzyme attractin and were highly positive for attractin in flow cytometric analysis. Fluorescence microscopy clearly demonstrated that attractin is located on the cell surface of monocytes. Attractin immunoprecipitates hydrolyzed Gly-Pro-pNA, indicating that monocyte-expressed attractin possesses DP IV-like activity. Inhibitor kinetic studies with purified human plasma attractin revealed that Lys[Z(NO(2))]-thiazolidide not only inhibits DP IV but also attractin (50% inhibition concentration=8.45 x 10(-9) M). Studying the influence of this inhibitor on monocyte functions, we observed a clear reduction of cell adhesion to fibronectin-coated culture plates in the presence of Lys[Z(NO(2))]-thiazolidide. Moreover, this inhibitor significantly modulates the production of interleukin-1 (IL-1) receptor antagonist, IL-6, and transforming growth factor-beta1 in lipopolysaccharide-stimulated monocyte cultures. In summary, here, we demonstrate for the first time expression of attractin on monocytes and provide first data suggesting that drugs directed to DP IV-like enzyme activity could affect monocyte function via attractin inhibition.
Adenosine Deaminase↗
Inhibitors of dipeptidyl peptidase IV and aminopeptidase N target major pathogenetic steps in acne initiation.
Acne is a chronic disease hallmarked by sebaceous hyperplasia, follicular hyperkeratosis, and inflammation. Parallel targeting of these factors is required to treat acne effectively. Inhibitors of dipeptidyl peptidase IV (DP IV) and aminopeptidase N (APN) show strong anti-inflammatory effects on immune cells and therapeutic efficacy in autoimmune disorders. Our investigation focused on the expression and functional relevance of these ectopeptidases in three cell types which exhibit an altered phenotype in early acne lesions. We showed for the first time expression of DP IV and APN on human sebocytes. In the SZ95 sebocyte cell line, the DP IV inhibitors Lys[Z(NO2)]-thiazolidide and Lys[Z(NO2)]-pyrrolidide and the APN inhibitors actinonin and bestatin suppressed proliferation, enhanced terminal differentiation, and slightly decreased total neutral lipid production. The anti-inflammatory and differentiation-restoring cytokine IL-1 receptor antagonist was significantly upregulated in SZ95 sebocytes and the HaCaT keratinocyte cell line in the presence of inhibitors. Furthermore, the inhibitors suppressed proliferation and IL-2 production of Propionibacterium acnes-stimulated T cells ex vivo and enhanced the expression of the immunosuppressive cytokine transforming growth factor-beta1. Our data provide first evidence for a functional role of DP IV and APN in the sebaceous gland apparatus and for their inhibitors, used alone or in combination, as completely new substances possibly affecting acne pathogenesis in a therapeutic manner.
Acne Vulgaris↗
Effect of L-arginine on asymmetric dimethylarginine (ADMA) or homocysteine-accelerated endothelial cell aging.
We investigated here the effect of l-arginine on asymmetric dimethylarginine (ADMA) or homocysteine-accelerated endothelial aging. Endothelial cells were cultured in medium containing 70micromol/L arginine until fourteenth passage. ADMA, dl-homocysteine, and l-arginine were replaced every 48h starting at the fourth passage. ADMA or homocysteine inhibited significantly the population doublings (PD) and accelerated the process of aging. Co-incubation with l-arginine enhanced PD, inhibited senescence associated beta-galactosidase activity, and increased telomerase activity. This effect was associated with an increase in NO synthesis and NO synthase protein expression. Furthermore, l-arginine-induced NO formation was accompanied by a reduction in oxidative stress and an increase in protein expression and enzyme activity of heme oxygenase (HO)-1. The NO synthase inhibitor l-NAME completely abolished the effect of l-arginine on ADMA or homocysteine-accelerated aging. These findings demonstrate that l-arginine prevents the onset of endothelial aging in ADMA or homocysteine-treated cells by increasing NO formation and consequently the induction of HO-1. This might provide a new strategy to delay ADMA or homocysteine-accelerated aging.
Aging↗
Rapid pacing of embryoid bodies impairs mitochondrial ATP synthesis by a calcium-dependent mechanism--a model of in vitro differentiated cardiomyocytes to study molecular effects of tachycardia.
Tachycardia may cause substantial molecular and ultrastructural alterations in cardiac tissue. The underlying pathophysiology has not been fully explored. The purpose of this study was (I) to validate a three-dimensional in vitro pacing model, (II) to examine the effect of rapid pacing on mitochondrial function in intact cells, and (III) to evaluate the involvement of L-type-channel-mediated calcium influx in alterations of mitochondria in cardiomyocytes during rapid pacing. In vitro differentiated cardiomyocytes from P19 cells that formed embryoid bodies were paced for 24 h with 0.6 and 2.0 Hz. Pacing at 2.0 Hz increased mRNA expression and phosphorylation of ERK1/2 and caused cellular hypertrophy, indicated by increased protein/DNA ratio, and oxidative stress measured as loss of cellular thiols. Rapid pacing additionally provoked structural alterations of mitochondria. All these changes are known to occur in vivo during atrial fibrillation. The structural alterations of mitochondria were accompanied by limitation of ATP production as evidenced by decreased endogenous respiration in combination with decreased ATP levels in intact cells. Inhibition of calcium inward current with verapamil protected against hypertrophic response and oxidative stress. Verapamil ameliorated morphological changes and dysfunction of mitochondria. In conclusion, rapid pacing-dependent changes in calcium inward current via L-type channels mediate both oxidative stress and mitochondrial dysfunction. The in vitro pacing model presented here reflects changes occurring during tachycardia and, thus, allows functional analyses of the signaling pathways involved.
Adenosine Diphosphate↗
Localization of neuregulin-1alpha (heregulin-alpha) and one of its receptors, ErbB-4 tyrosine kinase, in developing and adult human brain.
Using immunohistochemistry, Western blot analysis, and RT-polymerase chain reaction, we studied the distribution of neuregulin-1 splice variant alpha (NRG-1alpha) and one of its putative receptors, ErbB-4 tyrosine kinase, in human brain. In the pre- and perinatal human brain immunoreactivity was confined to numerous neurons, with the highest cell density found in cortical gray matter, hypothalamus and cerebellum. In the adult brain, single cortical gray and white matter neurons showed NRG-1alpha immunoreactivity. Occasionally, immunoreactive oligodendrocytes were observed. NRG-1alpha-expressing neurons were also found in the hypothalamus, hippocampus, basal ganglia and brain stem. Application of two antibodies recognizing alpha and beta isoforms revealed a different distribution pattern in that many cortical and hippocampal pyramidal neurons were labeled. ErbB-4 immunoreactivity was expressed in both neurons and oligodendrocytes. Our data show that NRG-1alpha expression is lower in the adult human brain than in the developing brain, and, therefore, support a role for NRG-1alpha in brain development.
Adult↗
A mutation in aminopeptidase N (CD13) isolated from a patient suffering from leukemia leads to an arrest in the endoplasmic reticulum.
Human aminopeptidase N (APN) is used as a routine marker for myelomonocytic cells in hematopoietic malignant disorders. Its gene and surface expressions are increased in cases of malignant transformation, inflammation, or T cell activation, whereas normal B and resting T cells lack detectable APN protein expression. In this study we elucidated the intracellular distribution, expression pattern, and enzymatic activity of a naturally occurring mutation in the coding region of the APN gene. At physiological temperatures the mutant protein is enzymatically inactive, persists as a mannose-rich polypeptide in the endoplasmic reticulum, and is ultimately degraded by an endoplasmic reticulum-associated degradation pathway. It shows in part the distinct behavior of a temperature-sensitive mutant with a permissive temperature of 32 degrees C, leading to correct sorting of the Golgi compartment accompanied by the acquisition of proper glycosylation but without reaching the cell-surface membrane and without regaining its enzymatic activity. Because the patient bearing this mutation suffered from leukemia, possible links to the pathogenesis of leukemia are discussed.
Aged↗
Dipeptidylpeptidase IV (DPIV) and alanyl-aminopeptidases (AAPs) as a new target complex for treatment of autoimmune and inflammatory diseases-proof of concept in a mouse model of colitis.
Explore the source record for details and available documents.
Animals↗
Possible role of DP IV inhibitors in acne therapy.
Explore the source record for details and available documents.
Acne Vulgaris↗
Dipeptidyl peptidase IV (DP IV, CD26) and aminopeptidase N (APN, CD13) as regulators of T cell function and targets of immunotherapy in CNS inflammation.
Explore the source record for details and available documents.
Animals↗
[Morphological remodeling in atrial fibrillation].
In the recent years, a tremendous amount has been learned about the pathophysiology of atrial fibrillation (AF). AF induces electrophysiological changes in the atria causing a perpetuation of the arrhythmia ("electrical remodeling"). Besides such AF-induced electrophysiological changes, which involve the downregulation of L-type calcium channels and thereby the calcium inward current, AF induces structural and ultrastructural changes in atrial tissue ("structural remodeling"). Calcium-dependent tissue alterations are induced by proteases and phosphatases like calpain and calcineurin. Furthermore, cardiac diseases like hypertension, heart failure, etc. activate the atrial angiotensin II system, and thereby, a progressive pro-arrhythmogenic atrial fibrosis is induced. Besides first clinical trials assessing the antiarrhythmic effects of angiotensin II receptor blockers in patients with AF, experimental data suggest that viral gene transfer can be used to transform fibroblasts to electrically conducting cardiomyocytes. This highly interesting methodology may be helpful to restore electrical conduction in fibrotic cardiac tissue.
Anti-Arrhythmia Agents↗
Assigning the phenotype of a natural regulatory T-cell to the human T-cell line, KARPAS-299.
The human CD30-positive anaplastic large (T-) cell lymphoma cell line, KARPAS-299 (DSM ACC31), was established from blast cells in the peripheral blood from a case of non-Hodgkin lymphoma in 1988. We describe the mRNA and surface expression in KARPAS-299 cells of a panel of markers highly restricted to human natural regulatory T-cells and associated with their suppressive activity, including FOXP3, CD25, IL-10, TGF-beta1, CD62L, and Lag-3. Results obtained from co-culturing human peripheral blood leukocytes with KARPAS-299 cells assigned a suppressive phenotype to the latter ones. In conclusion, KARPAS-299 cells show characteristics typical of natural regulatory T-cells and, thus, represent a valuable model for studying regulatory T-cell function, which may also facilitate drug development aimed at the modulation of regulatory T-cell activity for the pharmacological therapy of, for example, autoimmune diseases.
Cell Line, Tumor↗
Neuronal nitric oxide synthase controls enzyme activity pattern of mitochondria and lipid metabolism.
Mitochondria are affected by endogenous nitric oxide (NO). Besides effects of NO on mitochondrial enzymes and the stimulation of mitochondrial H2O2 production, a NO-dependent increase in mitochondrial biogenesis in several tissues has been reported. It is still obscure whether NO generated by one specific or different NO synthase (NOS) isoenzymes determine such effects. Therefore, we analyzed the amount of mitochondria, respiratory chain enzyme complexes, and citrate synthase in the brain, muscle, heart, kidney, and liver by comparing wild-type (WT) mice and mice lacking the neuronal nitric oxide synthase isoform (nNOS-KO). Our results show that the activities of NADH:cytochrome c oxidoreductase and succinate cytochrome c oxidoreductase differ between WT and nNOS-KO mice. However, similar quantities of mitochondria were found in the homogenates of tissues in WT and nNOS-KO animals. Most impressive, higher activities and protein of citrate synthase were found in the brain, muscle, heart, kidney, and liver of nNOS-KO mice. Additionally, higher contents of fatty acid synthase and lipids were determined in the livers of nNOS-KO mice but not in the heart and brain. Furthermore, liver mitochondria from nNOS-KO mice consumed pyruvate at a higher rate and released more citric acid. Our data document a previously unrecognized role of endogenous NO in the regulation of lipid metabolism.
Animals↗
Different activation of mitogen-activated protein kinase and Akt signaling is associated with aggressive phenotype of human meningiomas.
PURPOSE: Activation of intracellular signaling cascades has been implicated in the growth control of benign meningiomas, but their role for meningioma progression and outcome is unknown. Here we determined the expression and function of proteins involved in mitogen-activated protein kinase (MAPK) and phosphinositol-3 kinase (PI3K)/Akt signaling in benign, atypical, and malignant meningiomas and studied their association with clinicopathologic data including meningioma recurrence. EXPERIMENTAL DESIGN: Expression of various MAPK and PI3K signaling proteins was determined in 70 primary meningiomas and, if present, in recurrent tumors by immunohistochemistry and Western blotting. The expression patterns in primary and recurrent tumors were related to clinical data. The effect of MAPK and PI3K pathway inhibition on cell proliferation and apoptosis was determined using a primary malignant meningioma cell culture. RESULTS: Atypical and malignant meningiomas showed higher levels of phospho-Akt compared with benign tumors, and their proliferation could be inhibited by PI3K blocking using wortmannin. PI3K inhibition did not induce apoptosis in malignant meningioma cells. In contrast, expression of phospho-Raf and phospho-MAPK was decreased in aggressive meningiomas compared with benign tumors, but MAPK inhibition by PD98059 resulted in tumor cell apoptosis and decreased proliferation. Reduced MAPK activation was associated with meningioma recurrence, and PI3K activation was associated with poor preclinical condition and brain invasion of malignant meningiomas. CONCLUSIONS: Both MAPK and PI3K/Akt pathways are activated at different levels in benign and malignant meningiomas. Activation of PI3K/Akt signaling contributes to the aggressive behavior of malignant meningiomas, whereas MAPK activation is involved in both proliferation and apoptosis of malignant meningiomas.
Aged↗
The number of lymph node metastases in gastric cancer correlates with the angiotensin I-converting enzyme gene insertion/deletion polymorphism.
PURPOSE: In the present study, we aimed to substantiate the putative significance of angiotensin I-converting enzyme (ACE) on gastric cancer biology by investigating the influence of its gene polymorphism on gastric cancer progression. EXPERIMENTAL DESIGN: Genomic DNA was purified from peripheral blood mononuclear cells or tissue specimens. Amplified ACE gene fragments were separated on agarose gels. D or I alleles were identified by the presence of 190- or 490-bp fragments, respectively. Local expression of ACE was investigated by immunohistochemistry. RESULTS: Twenty-four of 113 (21%) gastric cancer patients had the II, 57 (51%) the ID, and 32 (28%) the DD genotype. The distribution of the ACE genotypes did not differ significantly from the control group of 189 patients without gastric cancer. However, the ACE genotypes correlated with the number of lymph node metastases and the Unio Internationale Contra Cancrum (UICC) tumor stage. Patients with the II genotype had a highly significantly smaller number of lymph node metastases (P < 0.001) and a significantly lower UICC tumor stage (P = 0.01) than patients with the DD genotype. No correlation was found between tumor type, tumor location, local tumor growth, distant metastases, and the ACE genotype. The expression of ACE in gastric cancer was investigated by immunohistochemistry in 100 of 113 patients. ACE was expressed by endothelial cells in all (100%) specimens and by tumor cells in 56 (56%) specimens. CONCLUSIONS: Our study shows that ACE is expressed locally in gastric cancer and that the gene polymorphism influences metastatic behavior.
Aged↗