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P Verroust

Publications and source records attributed to P Verroust.

At least 19 recordsLinked to original sources
PubMed1992

Expression of cALLa/NEP on gliomas: a possible marker of malignancy.

First described on pre-B leukemia cells, the common acute lymphoblastic leukemia antigen (cALLa) is also expressed on glioma cells in vitro. Its identity to neutral endopeptidase (NEP) (E.C.3.24.11) was corroborated by our finding that cALLa positive glioma cells had NEP activity. To study cALLa/NEP distribution on glial tumours in vivo, we examined 76 brain tumour biopsies by immunostaining techniques on frozen tissue sections using anti-cALLa (FAH99) and anti-NEP (135 A 3) monoclonal antibodies. We found that 96% of grade 4 gliomas (25/26) expressed NEP. Whereas only 45% (4/9) of grade 3 or anaplastic astrocytomas did. In low grade gliomas, we found 2 positive tumours out of 21 tested (10%). Double immunostaining procedures revealed that NEP was co-expressed with GFAP. However no NEP could be detected on non-glial brain tumours nor on reactive astrocytes. These results suggest that cALLa/NEP expression could be linked to malignant progression of gliomas.

Adolescent↗
PubMed1992

Coexpression in humans by kidney and fetal envelopes of a 280 kDa-coated pit-restricted protein. Similarity with the murine target of teratogenic antibodies.

Experimental studies performed in the rat over the last three decades have shown that antibodies raised against kidney or yolk sac, which, in the rat, surrounds the embryo and serves as a placenta during the major part of pregnancy, induced fetal resorptions or malformations. It is generally considered that the teratogenic antibodies decrease internalization and degradation of maternal proteins by yolk sac epithelial cells leading to an inadequate supply of nutriments to the embryo. These observations demonstrating the pathogenic role of antibodies to fetal envelopes are of great potential interest in clinical pathology since most cases of fetal malformations in humans are of unknown cause. The authors have recently shown that the key teratogenic antibodies in the murine system were directed against a 280 kDa-coated pit protein (gp280) specific for the brush border of epithelial cells lining the renal proximal tubule and the yolk sac. This observation allows for the unique opportunity to search for a similar system in humans. In this study, the presence in humans of a protein closely related to murine gp280 is shown, as indicated by extensive immunologic crossreactivity, close apparent molecular weights, strong homology of bidimensional peptide maps, and restricted distribution at the organ and subcellular level. In addition to kidney and yolk sac, human gp280 was also detected within the coated pits of the placental syncytiotrophoblastic cells. When introduced in an in vitro rat embryo culture system, antibodies to human gp280-induced developmental anomalies in a dose-dependent manner. These observations indicate that the antigenic component of the murine model is present in humans and can give rise to heterologous antibodies that cause developmental anomalies, suggesting that the experimental model might be of significance in human pathology.

Animals↗
PubMed1991

[Contribution of experimental pathology to the understanding of human immune glomerulonephritis].

Immune glomerulonephritis (GN) progresses in three phases. Induction corresponding to the development of immune response; transduction characterized by the appearance of immunological reactants in the glomerulus, and mediation responsible for glomerular lesions and proteinuria. Studies of experimental models have resulted in significant advances in our understanding of these phases. The most striking acquisitions concern the genetic control of GN and its link with the major histocompatibility system; the identification of target antigens involved in Goodpasture's syndrome and in experimental epimembranous GN; the re-evaluation of the role played by circulating immune complexes in the in situ formation of immune complexes in the glomerular capillary wall; the identification of numerous mediatory systems (notably cytokines) which play an important part in glomerular inflammation and in the development of fibrosis. These advances may lead, in the short- or medium-term, to interesting therapeutic novelties.

Animals↗
PubMed1991

Presence of renin, angiotensinogen, angiotensin II in the lamb anterior pituitary gland: immunocytochemical study after cryoultramicrotomy.

The presence of renin, angiotensin I-converting enzyme and angiotensin II detected by immunocytochemistry in the adult male rat anterior pituitary has suggested the existence of a pituitary renin-angiotensin system. To establish another mammalian experimental model we have investigated the presence of renin, angiotensinogen, angiotensin I-converting enzyme, and angiotensin II II in five normal lamb anterior pituitaries by immunocytochemistry after cryoultramicrotomy. Renin, angiotensinogen and angiotensin II immunoreactivities were observed only in cytoplasmic granules of lactotrophs, and the three proteins were found co-localized with prolactin in the same granules by double immunolabelling. No immunoreactive angiotensin I-converting enzyme was observed. These results suggest an activation of renin in the cytoplasmic granules of lactotrophs leading to a local synthesis of angiotensin II. Thus, the lamb anterior pituitary may provide a good experimental model for investigating the possible autocrine action of a local renin-angiotensin system on prolactin release in the human pituitary.

Angiotensin II↗
PubMed1991

Immunoautoradiographic localisation of enkephalinase (EC 3.4.24.11) in rat gastrointestinal tract.

Enkephalinase (EC 3.4.24.11, membrane metalloendopeptidase) is a zinc peptidase expressed by neurons and a variety of epithelial cells, and responsible for the inactivation of enkephalins in brain. Its functions in the gastrointestinal (GI) tract are less well understood although enkephalinase inhibitors were reported to induce a constellation of antisecretory and motor responses. Its localisation in various segments of the rat GI tract was established autoradiographically using a 125I-labelled monoclonal antibody. All along the GI tract, the highest immunoreactivity was found in mucosal layers e.g., in intestinal villi, basal epithelial layers of the oesophagus or gastric cardia, muscularis mucosae of the stomach and large intestine. The immunoreactivity was also high in the stomach submucosae and moderate in the muscularis propria of the caecum. A faint patchy immunoreactivity was also observed in several other layers. This distribution suggests that the membrane peptidase is expressed by enterocytes and a variety of other cells. Its high expression in mucosal layers is consistent with its participation in protein digestion and also in the inactivation of endogenous peptides, particularly the enkephalins, acting at this level to control secretory mechanisms and hydroelectrolytic fluxes. Its presence in submucosal layers may account for some naloxone-reversible motor responses elicited by enkephalinase inhibitors.

Animals↗
PubMed1990

Polarized membrane expression of brush-border hydrolases in primary cultures of kidney proximal tubular cells depends on cell differentiation and is induced by dexamethasone.

To analyze the influence of cell differentiation and the effects of hormones on the subcellular distribution of apical antigens in polarized epithelial cells, we have compared the localization of three brush border (BB) hydrolases [neutral endopeptidase (ENDO), aminopeptidase N (APN), and dipeptidylpeptidase IV (DPPIV)] in primary cultures of renal proximal tubule cells grown in various culture media. The degree of cell differentiation modulated by medium composition was estimated by measuring proximal functions, including glucose transport, specific enzymatic activities, and PTH responsiveness. In the dedifferentiated state observed in cells grown in 1% fetal calf serum (FCS)-supplemented medium, the three hydrolases are abnormally concentrated in a cytoplasmic vesicle compartment with weak expression on both membrane domains. By contrast, in serum-free hormonally defined medium (DM: insulin, 5 microgram/ml; dexamethasone, 5 x 10(-8) M), which markedly enhances morphological and functional cell differentiation, the distribution of hydrolases parallels that observed in the normal tubule. When added to the DM devoid of hormones, insulin has little polarizing effect, whereas dexamethasone dramatically increases the apical expression of the hydrolases, which then almost disappear from the basolateral membrane and cytoplasmic vesicular compartments. This glucocorticoid hormone augments the amount of immunoreactive antigen detectable on the apical domain in paraformaldehyde-fixed cells but does not change the total enzymatic activity. This suggests the presence in tubular cells of a dexamethasone-dependent polarizing machinery that requires de novo RNA and protein synthesis, and probably acts mainly by targeting a storage cytoplasmic pool of enzyme to the apical domain.

Aminopeptidases↗
PubMed1990

Circulating immune complexes in systemic necrotizing vasculitis of the polyarteritis nodosa group. Comparison of HBV-related polyarteritis nodosa and Churg Strauss Angiitis.

Levels of immune complexes (IC) were measured before treatment in 16 patients affected with classic polyarteritis nodosa (PN) or Churg Strauss Angiitis (CSA). The six patients with PN were positive for HBV markers. The others presented severe asthma. IgG containing immune complexes were measured using Raji cell assay. Normal level was 4,642 +/- 509 (mean +/- SEM). IC levels were significantly different in patients with and without HBV markers. When HBV was present, mean IC level was 7,185 +/- 2,472. In the absence of HBV markers, mean IC level was 26,462 +/- 10,796. These results confirm that systemic vasculitis is an heterogeneous group of diseases and further suggest that pathogenesis of vasculitis is different in patients with asthma and those with HBV markers.

Antigen-Antibody Complex↗
PubMed1990

Role of a 90-kD glycoprotein in Heymann's nephritis.

Heymann's nephritis can be induced in rats by injection of antibodies (Ab) against the major nephritogenic antigen (Ag) (gp330). We previously reported on a 90-kD tubular-glomerular glycoprotein (gp90) having enzymatic activity (dipeptidyl-peptidase IV) which, after antibody interaction, induces a transient Heymann-like immunofluorescence pattern. In the present study we have analysed the ultrastructural features of the renal immune reaction occurring in rats after injection of a monoclonal antibody to gp90, revealed by a pre-embedding immunogold staining (5-nm particles). In the early stage (10-60 min) gold granules were found along the glomerular capillary walls mainly in the endothelial region. During the intermediate stage (24-48 h) the brush border microvilli were diffusely labelled. In the late stage (1-2 weeks) gold particles were still noticed at the tubular level. This work suggests that the immune reaction in Heymann's nephritis also occurs on the endothelial side of the glomerular capillary walls, thus facilitating the passage of epithelial-specific antibody. The tubular kinetics confirms that gp90 may play a role in the metabolic activity of tubular proximal cells. Because this antigen has been demonstrated in human kidney as well, it may be relevant to some membranous or other human nephropathies.

Animals↗
PubMed1990

Electron microscopic localization of immunoreactive enkephalinase (EC 3.4.24.11) in the neostriatum of the rat.

The fine structural distribution of the enzyme-neutral endopeptidase EC 3.4.24.11 (enkephalinase) was examined by immunoradioautography (using an iodinated monoclonal antibody) and peroxidase immunocytochemistry (using the same probe in nonradioactive form) in the neostriatum of the rat. At the light microscopic level, both techniques revealed a heterogeneous distribution of immunoreactive enkephalinase in the caudoputamen, characterized by the presence of patches of intense immunolabeling prominent against a relatively strong immunoreactive matrix, a pattern reminiscent of mu opioid receptors radioautographically labeled in the same region. Pilot experiments indicated that fixation of the brain with a mixture of 4% paraformaldehyde, 0.05% glutaraldehyde, and 0.2% picric acid did not modify the distribution and only slightly reduced the intensity of striatal enkephalinase antigenicity, provided that the post-fixation period did not exceed 1 hr. In the neostriatum of animals fixed according to this protocol, enkephalinase immunoreactivity was found by electron microscopic immunoradioautography to be exclusively confined to neuronal and glial membrane interfaces. Immunoperoxidase cytochemistry confirmed the association of immunoreactive enkephalinase with the plasma membrane of neurons and, to a lesser extent, of astrocytes and oligodendrocytes. Both immunoradioautographic and immunoperoxidase techniques revealed a predominant association of the enzyme with neuronal perikarya and dendrites. The morphological features of the labeled perikarya, together with the presence of immunoreactive dendritic spines, suggested that some of these neurons corresponded to striatofugal medium spiny neurons. Immunoreactive enkephalinase was also detected at the level of myelinated and unmyelinated axons and axon terminals. These axons could potentially have originated from intrinsic striatal neurons or from the substantia nigra. Statistical analysis of silver grain distribution in electron microscopic immunoradioautographs indicated that immunoreactive enkephalinase was not preferentially concentrated at the level of specific membrane interfaces, but rather, was more or less uniformly distributed on the surface of neurons and/or glial cells. A similarly diffuse localization of the enzyme was apparent in peroxidase-reacted material, though the latter technique also revealed a microheterogeneity in the deposition of the reaction product along the labeled membranes. Finally, quantitative analysis of immunoradioautographs clearly indicated an absence of enkephalinase enrichment at the level of synaptic junctions. The similarity between the light and electron microscopic distribution of enkephalinase observed in the present study, and that previously reported for mu opioid receptors, lends support to the concept that this ectoenzyme may be involved in the inactivation of endogenous opioids in the mammalian neostriatum.

Animals↗
PubMed1989

Human glioma cell lines expressing the common acute lymphoblastic leukemia antigen (cALLa) have neutral endopeptidase activity.

Several established human glioma cell lines have been previously shown to express the common acute lymphoblastic leukemia antigen (cALLa, CD 10), an important marker in the diagnosis of human acute lymphocytic leukemia (ALL). The amino acid sequence of cALLa is identical to that of neutral endopeptidase (NEP,E.C.3.4.24.11), and cALLa expressed on leukemia and melanoma cell lines is enzymatically active NEP. In the present study, we investigated whether cALLa expressed on glioma cell lines is active NEP. We detected cALLa on 10 out of 13 glioma cell lines using 2 different anti-cALLa MAbs (A12-G4 and FAH99). NEP antigen, as detected by immunostaining with an anti-NEP MAb (135A3), was expressed on the same 10 lines. cALLa-positive, but not cALLa-negative cell lines displayed an endopeptidase activity. This activity could be blocked by phosphoramidon, a specific inhibitor of NEP. Furthermore, mRNAs hybridizing to an NEP-specific probe were present in cALLa-positive glioma cells but not in cALLa-negative cells. Taken together, the results provide strong evidence that cALLa-positive glioma cell lines express endopeptidase activity on the cell surface.

Antigens, CD↗
PubMed1989

Maintenance of proximal and distal cell functions in SV40-transformed tubular cell lines derived from rabbit kidney cortex.

This paper reports the preparation and describes the properties of three renal tubular cell lines derived using SV40 infection of primary cultures of rabbit kidney cortical cells, enriched in proximal cells. RC.SV1 was initially derived from cultures grown in the presence of fetal calf serum exhibiting a low degree of proximal differentiation. The cells were subsequently adapted to grow in serum-free hormonally defined medium and display basic properties of proximal tubule cells including well-developed apical microvilli, strong expression of brush-border hydrolases, Na+-coupled glucose uptake, and increased cyclic AMP production when exposed to PTH. The other two cell lines were derived from cultures in serum-free hormonally defined medium and propagated in the same medium. They are characterized by some common properties including rare and short microvilli, low expression of apical hydrolases, and low or undetectable Na+-dependent glucose uptake, but differ by their abilities to respond by an increase in cAMP to various hormonal stimuli. RC.SV2 cells are sensitive to calcitonin and to a lesser extent to isoproterenol and PTH, suggesting that they may originate from the thick ascending limb of Henle's loop and the bright portion of the distal tubule. RC.SV3 responds essentially to isoproterenol and arginine vasopressin, suggesting a more distal origin (late distal and initial collecting tubule). Emergence of distal cell lines from cultures exhibiting proximal characteristics may be related to distal cell overgrowth as suggested by analysis of growth kinetics and increased Na+/H+ exchanger activity in RC.SV2 compared with RC.SV1.

Animals↗
PubMed1989

Detailed immunoautoradiographic mapping of enkephalinase (EC 3.4.24.11) in rat central nervous system: comparison with enkephalins and substance P.

The metallopeptidase enkephalinase known to participate in the inactivation of endogenous enkephalins and, possibly, other neuropeptides such as tachykinins, was visualized by autoradiography using a [125I]iodinated monoclonal antibody. A detailed mapping of the enzyme in rat brain and spinal cord was established on 10-micron serial sections prepared in a frontal plane as well as a few sections in a sagittal plane. On adjacent sections, and for the purpose of comparison, substance P-like and enkephalin-like immunoreactivities were also visualized by autoradiography using a 125I-monoclonal antibody and a polyclonal antibody detected by a secondary 125I-anti-rabbit antibody respectively. Histological structures were identified on adjacent Nissl-stained sections. Using the highly sensitive 125I-probe, enkephalinase immunoreactivity was found to be distributed in a markedly heterogeneous manner in all areas of the central nervous system. Immunoreactivity was undetectable in white matter areas, for example the corpus callosum or fornix, and had a laminar pattern in, for example, the cerebral cortex or hippocampal formation. Hence, although immunodetection was not performed at the cellular level, a major neuronal localization of the peptidase is suggested. The latter is consistent with the detection of a strong immunoreactivity in a pathway linking the striatum to the globus pallidum, the entopeduncular nucleus and the substantia nigra, as well as with a series of biochemical and lesion data. The strong immunoreactivity also present in choroid plexuses and ependymal cells as well as in the intermediate lobe and in scattered cells of the anterior lobe of the pituitary suggests that populations of glial and endocrine cells also express the peptidase. The highest density of enkephalinase immunoreactivity was observed in basal ganglia and limbic areas (caudate putamen, globus pallidus, nucleus accumbens, olfactory tubercles) as well as in areas involved in pain control mechanisms (superficial layers of the spinal nucleus of the trigeminal nerve or of the dorsal horn of the spinal cord) which also display the highest immunoreactivities for both enkephalins and substance P (except in globus pallidus for the latter). These localizations account for the opioid-like analgesic and motor effects of enkephalinase inhibitors inasmuch as a selective or predominant participation of the peptidase in enkephalin inactivation is assumed. A number of other areas appear richly endowed in both enkephalinase and enkephalins whereas substance P is hardly detectable. This is particularly the case for the olfactory bulb, bed nucleus of the accessory olfactory tract, the cerebellum (where enkephalinase mainly occurs in the molecular layer) and the hippocampal formation (namely in the molecular layer of the dentate gyrus).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Common acute lymphoblastic leukemia antigen expressed on leukemia and melanoma cell lines has neutral endopeptidase activity.

We have previously reported that the amino acid sequence of the common acute lymphoblastic leukemia antigen (CALLA, CD10) translated from a normal human kidney cDNA clone is identical to that of neutral endopeptidase (NEP, EC 3.4.24.11). In this study, we show that by flow cytometry, a monoclonal antibody (135A3) produced against rabbit NEP reacted selectively with leukemia and melanoma cell lines expressing CALLA on their surface. A glycoprotein of apparent Mr 100,000 was immunoprecipitated from surface labeled NALM-1 leukemia or Mel-1477 melanoma cells with monoclonal antibodies to NEP (135A3) or CALLA (44C10). mRNAs hybridizing to a NEP-specific probe were present in CALLA+ leukemia and melanoma cell lines, but absent from CALLA- lines. NEP enzymatic activity was detected on intact cells from CALLA+ lines, but not CALLA- lines. The activity was blocked by two selective inhibitors of NEP, thiorphan and phosphoramidon. CALLA antigen purified from the NALM-6 leukemic cell line by affinity to 44C10-IgG Sepharose retained a peptidase activity that was completely blocked by thiorphan and phosphoramidon. Thus the CALLA antigen present at the surface of leukemia and melanoma cell lines is an enzymatically active neutral endopeptidase.

Antibodies, Monoclonal↗
PubMed1989

Antigenic targets in epimembranous glomerulonephritis. Experimental data and potential application in human pathology.

Although membranous glomerulonephritis (MGN) has been long considered as a prototype of glomerulonephritis (GN) due to the deposition of circulating immune complexes (CIC), a growing body of evidence indicates that immune deposits can also be formed in situ and implicate antigens expressed by glomerular epithelial cells (GEC). Some of these antigens have recently been identified. The first one, gp330 - a 330-kd glycoprotein restricted to the coated pits of GEC and renal brush border (BB) - is responsible for Heymann nephritis, a rat model of MGN. However, it is absent in the human glomerulus and is therefore probably not involved in human cases of MGN, at least in those due to in situ formation of CIC. In addition, by raising monoclonal antibodies against rat and rabbit BB, we have isolated two other BB proteins also expressed on GEC. The latter, respectively identified as dipeptidyl peptidase IV (90 kd) and enkephalinase (85 kd), can serve as targets for the formation of short-lived immune deposits. Since they are also detected on human GEC, they might play a role in the pathogenesis of MGN in man.

Animals↗
PubMed1989

Involvement of an antigen distinct from the Heymann antigen in membranous glomerulonephritis in the mouse.

Membranous glomerulonephritis in the mouse can be induced by injection of a heterologous antiserum against murine pronase digested renal tubular antigens (TApron). The antigenic target in the glomerular capillary wall is different from the Heymann antigen (gp 330). It shows the characteristics of a smaller antigen (gp 90) that can also be detected by a monoclonal antibody. We isolated the anti-gp 90 component from the polyclonal antiserum by absorptions and elutions using mouse liver as a substrate, which lacks gp 330 but does express gp 90. Immunoprecipitation of radiolabeled renal proximal tubular brush borders demonstrated that the mouse liver eluate reacted with gp 90 but not with gp 330. In immunofluorescence, the eluate bound to the glomerular capillary wall of both mouse and rat in a homogeneous pattern. Injection of the eluate led to a transient, homogeneous binding to the glomerular capillary wall of the mouse and also, although to a lesser extent, to that of the rat. Injection in mice presensitized against rabbit immunoglobulins caused a more permanent granular binding in a pattern typical of membranous glomerulonephritis. The results demonstrate that an antigen with a molecular weight and a kidney distribution different from the Heymann antigen can serve as target for antibody-mediated membraneous glomerulonephritis in the mouse. Furthermore, they suggest that this antigen may also be involved in the membranous glomerulonephritis of the rat in addition to the Heymann antigen.

Animals↗
PubMed1989

[Formation of immune deposits during experimental extramembranous glomerulonephritis].

Recent studies of experimental models of membranous glomerulonephritis (MGN) induced by immunization against preparations of brush border have shown that in the classical model described by Heymann, the subepithelial immune deposits are formed in situ by binding of free circulating antibody to a 330 kDa glycoprotein expressed by tubular and glomerular epithelial cells. The role of other brush border antigens has been demonstrated in related models. The importance in pathology of the properties of the target antigens as well as of the secondary events taking place after the initial antigen antibody interaction has been established. The development of biochemical and immunological techniques will make it possible to extend these observations to human pathology.

Animals↗