Utilizing ethacrynic acid and ciclopirox olamine in liver cancer (2018)

Ahmad Al‑Dali Hans Weiher Ingo Schmidt‑Wolf

Once aberrantly activated, the Wnt/βcatenin pathway may result in uncontrolled proliferation and eventually cancer. Efforts to counter and inhibit this pathway are mainly directed against βcatenin, as it serves a role on the cytoplasm and the nucleus. In addition, speciallygenerated lymphocytes are recruited for the purpose of treating liver cancer. Peripheral blood mononuclear lymphocytes are expanded by the timely addition of interferon γ, interleukin (IL)1β, IL2 and anticluster of differentiation 3 antibody. The resulting cells are called cytokineinduced killer (CIK) cells. The present study utilised these cells and combine them with drugs inhibiting the Wnt pathway in order to examine whether this resulted in an improvement in the killing ability of CIK cells against liver cancer cells. Drugs including ethacrynic acid (EA) and ciclopirox olamine (CPX) were determined to be suitable candidates, as determined by previous studies. Drugs were administered on their own and combined with CIK cells and then a cell viability assay was performed. These results suggest that EAtreated cells demonstrated apoptosis and were significantly affected compared with untreated cells. Unlike EA, CPX killed normal and cancerous cells even at low concentrations. Subsequent to combining EA with CIK cells, the potency of killing was increased and a greater number of cells died, which proves a synergistic action. In summary, EA may be used as an antihepatocellular carcinoma drug, while CPX possesses a high toxicity to cancerous as well as to normal cells. It was proposed that EA should be integrated into present therapeutic methods for cancer.

Foveated Depth-of-Field Filtering in Head-Mounted Displays (2018)

Martin Weier Thorsten Roth André Hinkenjann Philipp Slusallek

In recent years, a variety of methods have been introduced to exploit the decrease in visual acuity of peripheral vision, known as foveated rendering. As more and more computationally involved shading is requested and display resolutions increase, maintaining low latencies is challenging when rendering in a virtual reality context. Here, foveated rendering is a promising approach for reducing the number of shaded samples. However, besides the reduction of the visual acuity, the eye is an optical system, filtering radiance through lenses. The lenses create depth-of-field (DoF) effects when accommodated to objects at varying distances. The central idea of this article is to exploit these effects as a filtering method to conceal rendering artifacts. To showcase the potential of such filters, we present a foveated rendering system, tightly integrated with a gaze-contingent DoF filter. Besides presenting benchmarks of the DoF and rendering pipeline, we carried out a perceptual study, showing that rendering quality is rated almost on par with full rendering when using DoF in our foveated mode, while shaded samples are reduced by more than 69%.

Lignocellulosic Biomass as Source for Lignin-Based Environmentally Benign Antioxidants (2018)

Abla Alzagameem Basma El Khaldi-Hansen Dominik Büchner Michael Larkins Birgit Kamm Steffen Witzleben Margit Schulze

Antioxidant activity is an essential feature required for oxygen-sensitive merchandise and goods, such as food and corresponding packaging as well as materials used in cosmetics and biomedicine. For example, vanillin, one of the most prominent antioxidants, is fabricated from lignin, the second most abundant natural polymer in the world. Antioxidant potential is primarily related to the termination of oxidation propagation reactions through hydrogen transfer. The application of technical lignin as a natural antioxidant has not yet been implemented in the industrial sector, mainly due to the complex heterogeneous structure and polydispersity of lignin. Thus, current research focuses on various isolation and purification strategies to improve the compatibility of lignin material with substrates and enhancing its stabilizing effect.

Amino Acids and Inherited Amino Acid-Related Disorders (2018)

Ina Knerr Laurie Bernstein Ellen Crushell Siobhan O’Sullivan Jörn Oliver Sass

Amino acids perform multiple essential physiological roles in humans, and accordingly, their importance to health has been the subject of extensive attention. In this special issue of the Journal of Nutrition and Metabolism, we focus on the various inborn errors of amino acid metabolism, their diagnostic challenges, new treatment approaches, and recent advances in patient monitoring as well as clinical outcomes.

The Human Mitochondrial DNA Depletion Syndrome Gene MPV17 Encodes a Non-selective Channel That Modulates Membrane Potential (2015)

Vasily D. Antonenkov Antti Isomursu Daniela Mennerich Miia H. Vapola Hans Weiher Thomas Kietzmann J. Kalervo Hiltunen

The human MPV17-related mitochondrial DNA depletion syndrome is an inherited autosomal recessive disease caused by mutations in the inner mitochondrial membrane protein MPV17. Although more than 30 MPV17 gene mutations were shown to be associated with mitochondrial DNA depletion syndrome, the function of MPV17 is still unknown. Mice deficient in Mpv17 show signs of premature aging. In the present study, we used electrophysiological measurements with recombinant MPV17 to reveal that this protein forms a non-selective channel with a pore diameter of 1.8 nm and located the channel's selectivity filter. The channel was weakly cation-selective and showed several subconductance states. Voltage-dependent gating of the channel was regulated by redox conditions and pH and was affected also in mutants mimicking a phosphorylated state. Likewise, the mitochondrial membrane potential (Deltapsim) and the cellular production of reactive oxygen species were higher in embryonic fibroblasts from Mpv17(-/-) mice. However, despite the elevated Deltapsim, the Mpv17-deficient mitochondria showed signs of accelerated fission. Together, these observations uncover the role of MPV17 as a Deltapsim-modulating channel that apparently contributes to mitochondrial homeostasis under different conditions.

Propofol restores the function of "hyperekplexic" mutant glycine receptors in Xenopus oocytes and mice (2004)

Sean Michael O'Shea Lore Becker Hans Weiher Heinrich Betz Bodo Laube

Human hereditary hyperekplexia ("startle disease") is a neurological disorder characterized by exaggerated, convulsive movements in response to unexpected stimuli. Molecular genetic studies have shown that this disease is often caused by amino acid substitutions at arginine 271 to glutamine or leucine of the alpha1 subunit of the inhibitory glycine receptor (GlyR). When exogenously expressed in Xenopus oocytes, agonist responses of mutant alpha1(R271Q) and alpha1(R271L) GlyRs show higher EC50 values and lower maximal inducible responses (relative efficacies) compared with oocytes expressing wild-type alpha1 GlyR subunits. Here, we report that the maximal glycine-induced currents (I(max)) of mutant alpha1(R271Q) and alpha1(R271L) GlyRs were dramatically potentiated in the presence of the anesthetic propofol (PRO), whereas the I(max) of wild-type alpha(1) receptors was not affected. Quantitative analysis of the agonist responses of the isofunctionally substituted alpha1(R271K) mutant GlyR revealed that saturating concentrations of PRO decreased the EC50 values of both glycine and the partial agonist beta-alanine by >10-fold, with relative efficacies increasing by 4- and 16-fold, respectively. Transgenic (tg) mice carrying the alpha1(R271Q) mutation (tg271Q-300) have both spontaneous and induced tremor episodes that closely resemble the movements of startled hyperekplexic patients. After treatment with subanesthetic doses of PRO, the tg271Q-300 mutant mice showed temporary reflexive and locomotor improvements that made them indistinguishable from wild-type mice. Together, these results demonstrate that the functional and behavioral effects of hyperekplexia mutations can be effectively reversed by drugs that potentiate GlyR responses.

AAV-encoded expression of TRAIL in experimental human colorectal cancer leads to tumor regression (2004)

A. Mohr G. Henderson L. Dudus I. Herr T. Kuerschner K-M Debatin H. Weiher K. J. Fisher R. M. Zwacka

Gene transfer vectors based on the adeno-associated virus (AAV) are used for various experimental and clinical therapeutic approaches. In the present study, we demonstrate the utility of rAAV as a tumoricidal agent in human colorectal cancer. We constructed an rAAV vector that expresses tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/Apo2L) and used it to transduce human colorectal cancer cells. TRAIL belongs to the TNF superfamily of cytokines that are involved in various immune responses and apoptotic processes. It has been shown to induce cell death specifically in cancer cells.

Disease-specific human glycine receptor alpha1 subunit causes hyperekplexia phenotype and impaired glycine- and GABA(A)-receptor transmission in transgenic mice (2002)

Lore Becker Jorg von Wegerer Johannes Schenkel Hanns-Ulrich Zeilhofer Dieter Swandulla Hans Weiher

Hereditary hyperekplexia is caused by disinhibition of motoneurons resulting from mutations in the ionotropic receptor for the inhibitory neurotransmitter glycine (GlyR). To study the pathomechanisms involved in vivo, we generated and analyzed transgenic mice expressing the hyperekplexia-specific dominant mutant human GlyR alpha1 subunit 271Q. Tg271Q transgenic mice, in contrast to transgenic animals expressing a wild-type human alpha1 subunit (tg271R), display a dramatic phenotype similar to spontaneous and engineered mouse mutations expressing reduced levels of GlyR. Electrophysiological analysis in the ventral horn of the spinal cord of tg271Q mice revealed a diminished GlyR transmission. Intriguingly, an even larger reduction was found for GABA(A)-receptor-mediated inhibitory transmission, indicating that the expression of this disease gene not only affects the glycinergic system but also leads to a drastic downregulation of the entire postsynaptic inhibition. Therefore, the transgenic mice generated here provide a new animal model of systemic receptor interaction to study inherited and acquired neuromotor deficiencies at different functional levels and to develop novel therapeutic concepts for these diseases.

Enhanced gamma-glutamyl transpeptidase expression and superoxide production in Mpv17-/- glomerulosclerosis mice (2001)

G. Wagner K. Stettmaier W. Bors H. Sies E. M. Wagner A. Reuter H. Weiher

Recently, gamma-glutamyl transpeptidase, which initiates cleavage of extracellular glutathione, has been shown to promote oxidative damage to cells. Here we examined a murine disease model of glomerulosclerosis, involving loss of the Mpv17 gene coding for a peroxisomal protein. In Mpv17-/- cells, enzyme activity and mRNA expression (examined by quantitative RT-PCR) of membrane-bound gamma-glutamyl transpeptidase were increased, while plasma glutathione peroxidase and superoxide dismutase levels were lowered. Superoxide anion production in these cells was increased as documented by electron spin resonance spectroscopy. In the presence of Mn(III)tetrakis(4-benzoic acid)porphyrin, the activities of gamma-glutamyl transpeptidase and plasma glutathione peroxidase were unchanged, suggesting a relationship between enzyme expression and the amount of reactive oxygen species. Inhibition of gamma-glutamyl transpeptidase by acivicin reverted the lowered plasma glutathione peroxidase and superoxide dismutase activities, indicating reciprocal control of gene expression for these enzymes.

Ultrastructural and physiological defects in the cochlea of the Mpv17 mouse strain (2001)

Angela M. Meyer zum Gottesberge Heidi Felix Alexander Reuter Hans Weiher

Ultrastructural investigations were performed in young (approximately 2 months) and old (7 months) Mpv17-negative and wild-type mice. The onset, the severity and the pattern of the degeneration significantly differed between both mice strains. In the wild-type mouse strain the degenerative changes of the cochlear structures were similar to the aging pattern described for other species. In contrast, the Mpv17 mutants showed degenerative changes of the cochlear structures already at the age of 2 months. The degenerative changes were patchy arranged throughout the entire length of the cochlea and involved the organ of Corti as well as the stria vascularis epithelia with alterations of the basement membrane of the capillaries. The severe sensorineural hearing loss and degenerative changes of the cochlear structures indicate that cochlear structures, especially the outer hair cells and the intermediate cells of the stria vascularis, are vulnerable to the missing Mpv17 gene product.

Course of renal injury in the Mpv17-deficient transgenic mouse (2000)

T. O'Bryan H. Weiher H. G. Rennke S. Kren T. H. Hostetter

The mutant Mpv17 mouse is a transgenic strain that fails to express a protein that is normally expressed in the kidney and that is associated with peroxisomes. The present studies provide a quantitative examination of renal function and structure in this strain compared to its control CFW strain. By 52 wk of age, the mutant strain developed proteinuria (urinary protein to creatinine ratio: 25 +/- 14 versus 3 +/- 1, mutant versus control), albuminuria (urinary albumin to creatinine ratio: 23 +/- 15 versus 0.1 +/- 0.1, mutant versus control), and hypoalbuminemia (2.1 +/- 0.4 versus 2.5 +/- 0.2 G/dl, mutant versus control), but without arterial hypertension or major reduction in filtration (serum creatinine 0.14 +/- 0.04 versus 0.18 +/- 0.12 mg/dl, mutant versus control). The Mpv17 glomeruli were enlarged (0.98 +/- 0.12 versus 0.52 +/- 0.02 micrometer(3) x 10(6), mutant versus control). Glomerular sclerosis became widespread (95 +/- 3 versus 23 +/- 32%, mutant versus control) and was preceded by mesangiolysis and microaneurysms. Tubulointerstitial disease was conspicuous by its absence. The intrarenal vasculature was normal in the mutant mice. Electron microscopy demonstrated focal foot process fusion and mesangiolysis. Thus, this mutant strain of mouse develops proteinuria and a distinct glomerulopathy including mesangiolysis but little interstitial injury all due to the loss of expression of a single gene.

Transient neuromotor phenotype in transgenic spastic mice expressing low levels of glycine receptor beta-subunit: an animal model of startle disease (2000)

Lore Becker Bettina Hartenstein Johannes Schenkel Jochen Kuhse Heinrich Betz Hans Weiher

Startle disease or hereditary hyperekplexia has been shown to result from mutations in the alpha1-subunit gene of the inhibitory glycine receptor (GlyR). In hyperekplexia patients, neuromotor symptoms generally become apparent at birth, improve with age, and often disappear in adulthood. Loss-of-function mutations of GlyR alpha or beta-subunits in mice show rather severe neuromotor phenotypes. Here, we generated mutant mice with a transient neuromotor deficiency by introducing a GlyR beta transgene into the spastic mouse (spa/spa), a recessive mutant carrying a transposon insertion within the GlyR beta-subunit gene. In spa/spa TG456 mice, one of three strains generated with this construct, which expressed very low levels of GlyR beta transgene-dependent mRNA and protein, the spastic phenotype was found to depend upon the transgene copy number. Notably, mice carrying two copies of the transgene showed an age-dependent sensitivity to tremor induction, which peaked at approximately 3-4 weeks postnatally. This closely resembles the development of symptoms in human hyperekplexia patients, where motor coordination significantly improves after adolescence. The spa/spa TG456 line thus may serve as an animal model of human startle disease.

The human papillomavirus type 11 upstream regulatory region triggers hair-follicle-specific gene expression in transgenic mice (1999)

J. Schenkel H. Gaissert E. E. Protopapa H. Weiher L. Gissmann A. Alonso

We have generated transgenic mice carrying the URR of the human papillomavirus type 11 ligated in front of the Escherichia coli beta-galactosidase coding region sequence. Using X-Gal staining to demonstrate beta-galactosidase production, we observed a hair-specific transcription of the reporter gene. This transcription was limited to the epithelial cells of the hair bulge region. The transgene was developmentally regulated, as no LacZ staining was demonstrated during embryogenesis and specific staining was first observed after birth. Surprisingly, dexamethasone and ultraviolet B, but not phorbol myristate acetate or progesterone treatment of the animals resulted in an increase in number and intensity of hair follicles expressing the reporter gene.

Age-dependent hypertension in Mpv17-deficient mice, a transgenic model of glomerulosclerosis and inner ear disease (1999)

Martine Clozel Patrick Hess Walter Fischli Bernd–Michael Löffler Ralf M. Zwacka Alexander Reuter Hans Weiher

The mutant mouse strain Mpv17-/-, carries a retroviral germline integration that inactivates the Mpv17 gene. Mpv17-deficient mice develop progressive glomerulosclerosis and sensineural deafness at early age. Characteristic basement membrane alterations are found in both sites of pathology. Mpv17 is a peroxisomal protein involved in the metabolism of reactive oxygen species, yet its molecular function is unknown. Dysregulation of antioxidant enzymes and basal membrane components has been established in this model and successful therapeutic intervention with antioxidants prove the causal role of reactive oxygen species in the development of the disease phenotype. We here investigated if the Mpv17-/- mice might be hypertensive. Indeed, our study revealed that Mpv17-/- mice developed significant systemic hypertension and tachycardia between 4 weeks and 5 months of age, accompanied by polyuria and elevated natriuresis. Judging from serum and urine parameters, the hypertensive condition develops concomitantly with the renal disease. Biochemical and pharmacological studies that used the endothelin receptor antagonist bosentan and the angiotensin converting enzyme inhibitor cilazapril indicated no involvement of the endothelin and renin-angiotensin systems in this hypertension, suggesting a potential novel mechanism of blood pressure regulation in this new murine hypertension model. Thus, Mpv17-/- mice unravel an intriguing new association between a defect in reactive oxygen metabolism and the age-dependent development of hypertension.

Glomerular Overproduction of Oxygen Radicals in Mpv17 Gene-Inactivated Mice Causes Podocyte Foot Process Flattening and Proteinuria (1999)

Christoph J. Binder Hans Weiher Markus Exner Dontscho Kerjaschki

Focal segmental glomerulosclerosis is a steroid-resistant glomerular disease characterized by foot process flattening and heavy proteinuria. A similar disease was found to occur spontaneously in mice in which the Mpv17 gene was inactivated by retroviral insertion (Mpv17-/- mice). Here evidence is provided that glomerular damage in this murine model is due to overproduction of oxygen radicals and accumulation of lipid peroxidation adducts that were found in isolated glomeruli of Mpv17-/- mice. The development of glomerular disease in Mpv17-/- mice was inhibited by scavengers of oxygen radicals (dithiomethylurea) and lipid peroxidation (probucol), but not by steroid treatment. Although the glomerular polyanion was greatly reduced in proteinuric Mpv17-/- mice, it was preserved by antioxidative therapy. These results indicate that the glomerular disease in Mpv17-/- mice qualifies as a model of steroid-resistant focal segmental glomerulosclerosis and that experimental therapies with scavengers of oxygen radicals and lipid peroxidation efficiently ameliorate glomerular damage.

Expression of the Recessive Glomerulosclerosis Gene Mpv17 Regulates MMP-2 Expression in Fibroblasts, the Kidney, and the Inner Ear of Mice (1998)

Alexander Reuter Andrea Nestl Ralf M. Zwacka Jan Tuckermann Rüdiger Waldherr Eva-Maria Wagner Matti Höyhtyä Angela M. Meyer Zum Gottesberge Peter Angel Hans Weiher

The recessive mouse mutant Mpv17 is characterized by the development of early-onset glomerulosclerosis, concomitant hypertension, and structural alterations of the inner ear. The primary cause of the disease is the loss of function of the Mpv17 protein, a peroxisomal gene product involved in reactive oxygen metabolism. In our search of a common mediator exerting effects on several aspects of the phenotype, we discovered that the absence of the Mpv17 gene product causes a strong increase in matrix metalloproteinase 2 (MMP-2) expression. This was seen in the kidney and cochlea of Mpv17-negative mice as well as in tissue culture cells derived from these animals. When these cells were transfected with the human Mpv17 homolog, an inverse causal relationship between Mpv17 and MMP-2 expression was established. These results indicate that the Mpv17 protein plays a crucial role in the regulation of MMP-2 and suggest that enhanced MMP-2 expression might mediate the mechanisms leading to glomerulosclerosis, inner ear disease, and hypertension in this model.

Loss of auditory function in transgenic Mpv17-deficient mice (1997)

Marcus Müller Jean W.T. Smolders Angela M. Zum Meyer Gottesberge Alexander Reuter Ralf M. Zwacka Hans Weiher Rainer Klinke

The transgenic mouse strain Mpv17 develops severe morphological degeneration of the inner ear and nephrotic syndrome at a young age (Meyer zum Gottesberge et al., 1996; Weiher et al., 1990). The audiograms (1-32 kHz) of Mpv17-negative mice were determined from auditory brain stem responses in young (2 months) and old (7 months) animals. Audiograms of age-matched wild-type mice with the same genetic background, but wild-type at the Mpv17 locus, were also determined. Furthermore, young Mpv17-negative mice that carried a human Mpv17 homologue gene were studied. NMRI mice served as a reference for normal hearing. Mpv17-negative mice suffer from severe sensorineural hearing loss as early as 2 months after birth. In the old Mpv17-negative mice no responses could be elicited at all. The 2 month old wild-type mice had normal audiograms, at 7 months only high threshold responses were seen. The poor audiograms of the Mpv17-negative mice are assumed to be the functional correlate of the morphological degeneration of the cochlea described earlier (Meyer zum Gottesberge et al., 1996). The finding that 2 out of 4 Mpv17-negative mice with the human Mpv17 gene had normal audiograms, shows that the gene inactivation can be functionally compensated by the human Mpv17 gene product.

Proviral inactivation of the Npat gene of Mpv 20 mice results in early embryonic arrest (1997)

M. Di Fruscio H. Weiher B. C. Vanderhyden T. Imai T. Shiomi T. A. Hori R. Jaenisch D. A. Gray

The Mpv 20 transgenic mouse strain was created by infection of embryos with a defective retrovirus. When Mpv 20 heterozygous animals were crossed, no homozygous neonatal mice or midgestation embryos were identified. When embryos from heterozygous crosses were cultured in vitro, approximately one quarter arrested as uncompacted eight-cell embryos, indicating that proviral insertion resulted in a recessive lethal defect whose phenotype was manifest very early in development. Molecular cloning of the Mpv 20 insertion site revealed that the provirus had disrupted the Npat gene, a gene of unknown function, resulting in the production of a truncated Npat mRNA. Expression of the closely linked Atm gene was found to be unaffected by the provirus.

Inner ear defect similar to Alport's syndrome in the glomerulosclerosis mouse model Mpv17 (1996)

A. M. Meyer zum Gottesberge A. Reuter H. Weiher

The Mpv17 mouse strain is a recessive transgenic mouse mutant that develops glomerulosclerosis and nephrotic syndrome at a young age. The phenotype results from a loss of function of a gene coding for a hydrophobic peroxisomal protein of 176 amino acids of 20 kDa following its destruction by retroviral integration. To investigate a potential effect of the missing Mpv17 function on the inner ear light and electron microscopic investigations were performed on the inner ears of Mpv17 mice and controls. These revealed degeneration of the stria vascularis and spiral ligament, loss of cochlear neurons and degeneration of the organ of Corti. The alterations observed here were similar to those described for Alport's syndrome, an inherited disorder characterized by progressive nephritis and neurosensory deafness. These findings indicate that although the molecular cause is different, the Mpv17 mouse model may share pathological mechanisms involved in patients with Alport's syndrome. At present the Mpv17 mouse appears to be a suitable animal model for this disease and may help to further elucidate the relationship between the kidney and the inner ear.

Low level expression of glycine receptor beta subunit transgene is sufficient for phenotype correction in spastic mice (1996)

B. Hartenstein J. Schenkel J. Kuhse B. Besenbeck C. Kling C. M. Becker H. Betz H. Weiher

Mutations in inhibitory glycine receptor (GlyR) subunit genes are associated with neuromotor diseases in man and mouse. To use the potential of the mouse mutants as animal models of human disease, we altered GlyR levels in mutant mice and studied their phenotype. A transgene coding for the beta subunit of the rat GlyR was introduced into the genetic background of the spa mutation, which is characterized by low endogenous expression levels of the beta subunit and a dramatic neuromotor phenotype. The resulting transgenic mice expressed the beta subunit mRNA at intermediate levels, and their phenotype was rescued. This provides formal proof for the casual relationship between GlyR beta gene mutation and motor disease, and indicates that a low level of beta gene expression (25% of normal) is sufficient for proper functioning of glycinergic synapses.

Functional rescue of the glomerulosclerosis phenotype in Mpv17 mice by transgenesis with the human Mpv17 homologue (1995)

Johannes Schenkel Ralf Michael Zwacka Christiane Rutenberg Alexander Reuter Rüdiger Waldherr Hans Weiher

The germ line insertion of a defective retrovirus into the Mpv17 gene of mice is associated with a recessive phenotype. Mice homozygous for the integration develop glomerulosclerosis at a young age. The phenotype resembles human glomerulosclerosis in its physiological parameters as well as in histology. A human homologue of the Mpv17 gene has been identified, isolated and analyzed. We here show that this gene, which has a role in the production of reactive oxygen species, can rescue the phenotype of Mpv17 deficient mice when introduced by transgenesis. This provides formal proof for the hypothesis that the phenotype is caused by the loss of function of the Mpv17 gene. It also provides evidence for the functional conservation of the Mpv17 gene in mammals and points to a potential role of this gene in human kidney disease.

Expression of interstitial collagenase during skeletal development of the mouse is restricted to osteoblast-like cells and hypertrophic chondrocytes (1995)

S. Gack R. Vallon J. Schmidt A. Grigoriadis J. Tuckermann J. Schenkel H. Weiher E. F. Wagner P. Angel

We determined the expression pattern of the matrix metalloproteinase interstitial collagenase (MMP-1) during mouse embryo development using in situ hybridization and immunohistochemistry. Localized MMP-1 mRNA was first detected at 14.5 days postconceptus. The spatial and temporal expression was restricted to areas of endochondral and intramembranous bone formation, such as in the mandibula, maxilla, clavicle, scapula, in the vertebrae, and in the dorsal, but not the ventral part of the ribs. The highest levels of MMP-1 transcripts and MMP-1 protein were found in the metaphyses and diaphyses of the long bones. MMP-1 was expressed by hypertrophic chondrocytes and by osteoblastic cells localized along the newly formed bone trabeculae. No expression was detected in osteoclasts. Two other related members of the MMP family, stromelysin-1 (MMP-3) and stromelysin-2 (MMP-10), were not expressed during days 7.5 and 16.5 of mouse embryogenesis. The tissue-specific expression of MMP-1 and the exclusive ability of interstitial collagenase to digest native collagen of types I, II, III, and X, the major components of bone, cartilage, and tendon, strongly suggests an important and specific function of this enzyme in bone development and remodeling.

The glomerulosclerosis gene Mpv17 encodes a peroxisomal protein producing reactive oxygen species (1994)

R. M. Zwacka A. Reuter E. Pfaff J. Moll K. Gorgas M. Karasawa H. Weiher

The mutant mouse strain Mpv17 carries a retroviral insert in its genome which inactivates the Mpv17 gene. At a young age these mice develop glomerulosclerosis and nephrotic syndrome which resembles human disease. We show here that the Mpv17 gene product is highly conserved and encodes a peroxisomal protein. Loss of the Mpv17 protein does not impair peroxisome biogenesis but instead leads to a reduced ability to produce reactive oxygen species (ROS). In turn, overproduction of the Mpv17 gene in transfected cells results in dramatically enhanced levels of intracellular ROS indicating a direct involvement of Mpv17 in ROS production. These data reveal a role for the Mpv17 protein in peroxisomal reactive oxygen metabolism and establish a novel link between peroxisomal ROS production and glomerulosclerosis.

Glomerular sclerosis in transgenic mice: the Mpv-17 gene and its human homologue (1993)

H. Weiher

The human homolog of the glomerulosclerosis gene Mpv17: structure and genomic organization (1993)

M. Karasawa R. M. Zwacka A. Reuter T. Fink C. L. Hsieh P. Lichter U. Francke H. Welher

Mice carrying a retroviral insert in both alleles of the Mpv17 gene develop glomerulosclerosis and nephrotic syndrome at young age. Thus, the Mpv17 gene is a recessive disease gene in mice and this mouse strain is a potential animal model for glomerular diseases in man. We here describe the isolation and analysis of a human homolog of this gene. By interspecies hybridisation cDNA clones representing a single RNA species were isolated from human liver. Sequence analysis revealed over 90% identify in a region coding for a protein of 176 amino acids and unknown function in both species. Cloning of the genomic locus revealed a single copy gene which we mapped to the short arm of chromosome 2 at band 2p23-p21. Determination of the intron-exon structure and the junction sequences enabled us to establish a PCR based procedure to isolate the coding region from human genomic DNA. Thus, it is now possible to analyse patients suffering from candidate diseases on the basis of a blood sample if biopsy material is not available.