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Biomedical subjects

A Cavaggioni

Publications and source records attributed to A Cavaggioni.

At least 19 recordsLinked to original sources
PubMed2002

Brain resistance to HSV-1 encephalitis in a mouse model.

Brain resistance to intracerebral superinfections develops after a peripheral inoculation of neurovirulent viruses. Superinfection resistance combines specificity, toward the virus used for the peripheral inoculum, and short-term duration after the inoculum. In order to study this unusual combination, neurovirulent superinfections were made on albino Swiss mice previously infected with a nasal inoculum. A herpesvirus strain SC16, or a homologue recombinant virus carrying the reporter lac Z gene or a vesicular stomatitis virus (VSV) (a virus taxonomically unrelated to Herpesviridae) were used. The mice underwent a neurological examination and their survival rate was recorded. The brains superinfected with the reporter virus were stained for the beta-galactosidase reaction to trace the virus spread and the inflammatory infiltrates were characterized immunocytochemically. The results confirm and extend previous observations about virus specificity and short-term duration of superinfection resistance. They show, moreover, an enhanced brain inflammation with T-cells and macrophages infiltrating the tissue around microvessels, at a time when both neurovirulence and the spread of herpesvirus in the brain are reduced. The results suggest that the immune response to superinfection in the nervous tissue is enhanced by blood-brain barrier mechanisms that promote the timely extravasation of immune cells.

Animals↗
PubMed2001

Individual recognition in mice mediated by major urinary proteins.

The ability to recognize individuals is essential to many aspects of social behaviour, such as the maintenance of stable social groups, parent-offspring or mate recognition, inbreeding avoidance and the modulation of competitive relationships. Odours are a primary mediator of individuality signals among many mammals. One source of odour complexity in rodents, and possibly in humans, resides in the highly polymorphic major histocompatibility complex (MHC). The olfactory acuity of mice and rats allows them to distinguish between the urinary odours of congenic strains differing only in single genes within the MHC, although the chemical mediators or odorants are unknown. However, rodent urine also contains a class of proteins, termed major urinary proteins (MUPs), that bind and release small volatile pheromones. We have shown that the combinatorial diversity of expression of MUPs among wild mice might be as great as for MHC, and at protein concentrations a million times higher. Here we show in wild house mice (Mus domesticus) that urinary MUPs play an important role in the individual recognition mechanism.

Animals↗
PubMed2001

Determining the binding capability of the mouse major urinary proteins using 2-naphthol as a fluorescent probe.

The mouse major urinary proteins (MUPs) are an ensemble of isoforms secreted by adult male mice and involved in sexual olfactory communication. MUPs belong to the lipocalin superfamily, whose conserved structure is a beta-barrel made of eight antiparallel beta-strands forming a hydrophobic pocket that accommodates small organic molecules. A detailed knowledge of the molecular mechanism associated to the binding of those molecules can guide protein engineering to devise mutated proteins where the ligand specificity, binding affinity, and release rate can be modulated. Proteins with such peculiar properties may have interesting biotechnological applications for pest control, as well as in food and cosmetic industries. In this work, we demonstrate that the fluorescent molecule 2-naphthol binds to the natural ligand's binding site of MUPs with high affinity. In addition, we show that 2-naphthol binds to MUPs in its protonated form, that its fluorescence is blue-shifted, and the quantum yield is increased, thus confirming the high hydrophobicity of the protein pocket and the absence of proton acceptors inside the binding site. At large the results presented, besides demonstrating that the use of 2-naphthol provides a convenient and quick method for testing MUPs binding activity and to ascertain the quality of the protein preparation, suggest that MUPs can represent an interesting system for studying the photophysical characteristics of fluorescent molecules in a highly hydrophobic environment.

Animals↗
PubMed2000

Major urinary proteins, alpha(2U)-globulins and aphrodisin.

The major urinary proteins (MUPs) are proteins secreted by the liver and filtered by the kidneys into the urine of adult male mice and rats, the MUPs of rats being also referred to as alpha(2U)-globulins. The MUP family also comprises closely related proteins excreted by exocrine glands of rodents, independently of their sex. The MUP family is an expression of a multi-gene family. There is complex hormonal and tissue-specific regulation of MUP gene expression. The multi-gene family and its outflow are characterized by a polymorphism which extends over species, strains, sexes, and individuals. There is evidence of evolutionary conservation of the genes and their outflow within the species and evidence of change between species. MUPs share the eight-stranded beta-barrel structure lining a hydrophobic pocket, common to lipocalins. There is also a high degree of structural conservation between mouse and rat MUPs. MUPs bind small natural odorant molecules in the hydrophobic pocket with medium affinity in the 10(4)-10(5) M(-1) range, and are excreted in the field, with bound odorants. The odorants are then released slowly in air giving a long lasting olfactory trace to the spot. MUPs seem to play complex roles in chemosensory signalling among rodents, functioning as odorant carriers as well as proteins that prime endocrine reactions in female conspecifics. Aphrodisin is a lipocalin, found in hamster vaginal discharge, which stimulates male copulatory behaviour. Aphrodisin does not seem to bind odorants and no polymorphism has been shown. Both MUPs and aphrodisin stimulate the vomeronasal organ of conspecifics.

Alpha-Globulins↗
PubMed2000

Aloe-emodin is a new type of anticancer agent with selective activity against neuroectodermal tumors.

Here we report that aloe-emodin (AE), a hydroxyanthraquinone present in Aloe vera leaves, has a specific in vitro and in vivo antineuroectodermal tumor activity. The growth of human neuroectodermal tumors is inhibited in mice with severe combined immunodeficiency without any appreciable toxic effects on the animals. The compound does not inhibit the proliferation of normal fibroblasts nor that of hemopoietic progenitor cells. The cytotoxicity mechanism consists of the induction of apoptosis, whereas the selectivity against neuroectodermal tumor cells is founded on a specific energy-dependent pathway of drug incorporation. Taking into account its unique cytotoxicity profile and mode of action, AE might represent a conceptually new lead antitumor drug.

Animals↗
PubMed2000

Asymptomatic herpes simplex type 1 virus infection of the mouse brain.

An asymptomatic and transitory brain infection takes place in adult Swiss CD-1 mice after intranasal inoculation of HSV-1 strain SC16. Time course and distribution of the infection in the brain are demonstrated, (i) by titration of the nasal tissue and olfactory bulbs for 16 days post-infection (p.i.), showing a maximum production yield on day 7 p.i. and no replicating virus on day 16 p. i.; (ii) expression in the brain of the lac Z reporter gene of HSV-1 strain SC16-DeltaUS5-lac Z consistent with a central spread of the virus through the central olfactory pathways and the trigeminal system as described in acute HSV-1 encephalitis models; (iii) PCR amplifications of a segment of the thymidine kinase gene (HSV-tk) showing the persistence of viral genome in the nasal tissue and olfactory bulbs after clearance of infectious virus. The asymptomatic character of the infection is demonstrated over 2 months p.i. (i) by normal body weight; (ii) a neurological survey which excludes motor, sensory, balance and postural signs; (iii) two behavioral tests, the open-field test for exploratory activity and the cookie-finding test for olfactory search. On the other hand, intracerebral inocula cause encephalitis and death in a few days (LD50 ca. 14 p.f.u.). Intracranial, surgical transection of one olfactory nerve does not prevent infection of the corresponding bulb nor does it modify virus distribution, suggesting multiple entry routes from the nasal cavity to the brain. In conclusion, HSV-1 strain SC16 reaches the brain of CD-1 mice from the nasal cavity and replicates without neurological or behavioral signs.

Animals↗
PubMed1999

Immunohistochemical investigation of the vomeronasal organ. Nitric oxide synthase expression in the mouse during postnatal development.

The expression of nitric oxide synthase type I (NOS-I), the key enzyme for the synthesis of the gaseous neurotransmitter nitric oxide, was investigated by means of immunohistochemistry in the vomeronasal organ (VNO) of mice from postnatal day 1 for 2 months. The results show that NOS is expressed in extrinsic nerve supplying the developing erectile tissue of VNO (the so-called VNO pump) as well as blood vessels in the connective tissue laying under the receptor epithelium at postnatal day 1. At 8, 15 and 21 postnatal days, and at 2 months the density of NOS-1-immunoreactive nerves goes along with the development of the erectile tissue. From postnatal day 8 onwards, NOS-1-immunoreactive fibers are found also in the vicinity of the VNO glands. These data suggest that nitric oxide (NO) modulates VNO activity early after birth in the mouse.

Age Factors↗
PubMed1999

Gene therapy of glioblastoma multiforme via combined expression of suicide and cytokine genes: a pilot study in humans.

Retrovirus-mediated gene therapy is a particularly attractive approach for glioblastoma multiforme (GBM), given the poor prognosis of this tumour and its localized proliferation in post-mitotic tissue. In this study we assessed, for the first time in humans, the therapeutic potential of a newly designed bicistronic Moloney vector (pLIL-2-TK), combining the expression of a suicide gene (thymidine kinase, tk) with an immunomodulatory gene (human interleukin 2, IL-2). Evidence of transgene activity in the treated tumours is presented.

Adult↗
PubMed1999

alpha-Gustducin expression in the vomeronasal organ of the mouse.

The expression of alpha-gustducin, a G protein alpha subunit involved in bitter and sweet taste transduction, was investigated in chemosensory tissues of adult mice. By immunohistochemistry, alpha gustducin was absent in the olfactory neuroepithelium. Instead, alpha gustducin was expressed in a subset of bipolar cells in the proliferative zone of the vomeronasal neuroepithelium as well as in taste buds. Northern blot analysis confirmed the presence of alpha gustducin in isolated vomeronasal organs. Moreover, immunohisto- chemistry revealed the expression of alpha gustducin in scattered cells of the nasal respiratory epithelium. These results show for the first time that alpha gustducin is expressed in chemosensory tissue outside the alimentary tract, suggesting that common transduction mechanisms could be shared by apparently unrelated chemosensory tissues.

Animals↗
PubMed1999

Pheromone signalling in the mouse: role of urinary proteins and vomeronasal organ.

The lipocalin protein family is characterized in structure by a conserved hydrophobic pocket which can bind small volatile odorants. The Major Urinary Proteins (MUPs) are a class of lipocalins found in the urine of adult male mice which concentrate in the urine odorants which confer a characteristic odor. The behavioural as well as the endocrine effects of mouse urine and MUPs are briefly reviewed, suggesting a complex role is pheromonal communication. Some recent data on the molecular receptors of the vomeronasal organ further suggest a complex interaction with the MUP system.

Alpha-Globulins↗
PubMed1997

Expression of a lipocalin in Pichia pastoris: secretion, purification and binding activity of a recombinant mouse major urinary protein.

The proteins of the mouse major urinary protein complex (MUP), members of the lipocalin family, bind volatile pheromones and interact with the vomeronasal neuroepithelium of the olfactory system. We report the expression of a MUP protein using its native signal sequence for secretion in the methylotrophic yeast, Pichia pastoris. Mature recombinant MUP (rMUP) is secreted at a concentration of 270 mg/l in minimal medium and it is isolated from the culture supernatant by one step ion-exchange chromatography in a nearly pure form. Binding activity, tested with an odorant molecule which displays high affinity for native MUP, indicates that rMUP has a behavior similar to the native one. This finding suggests that the protein, and in particular its hydrophobic binding pocket, is properly folded.

Alpha-Globulins↗
PubMed1997

Gene stereotactic neurosurgery for recurrent malignant gliomas.

Four patients affected by glioblastoma recurrence were treated with a gene therapy-immunotherapy protocol consisting of intratumoral injections of culture cells producing a retroviral vector which expresses human interleukin-2 and the herpes simplex virus thymidine kinase genes. Seven to 14 days after implantation, the patients were treated with ganciclovir at standard doses. Anatomopathological and immunohistochemical data confirm the efficacy of transduction. From the clinical point of view, gene therapy combined with immunotherapy demonstrated safety and a short-range but clearcut oncolytic effect.

Brain Neoplasms↗
PubMed1995

Acceleration of puberty onset in female mice by male urinary proteins.

1. Puberty onset in female mice is accelerated by exposure to conspecific adult male urine, which acts through the vomeronasal organ and the accessory olfactory system. A distinctive component of adult male mouse urine is the major urinary protein complex (MUP), which is a lipocalin; it has a hydrophobic pocket that binds small endogenous volatile molecules. The MUP gene family also codes for a hexapeptide, which has four residues in common with the N-terminal region of MUP. 2. MUP, the volatiles bound to MUP and the MUP-related hexapeptide have been tested for the induction of puberty acceleration by measuring the increase in uterus weight related to the first pro-oestrus phase. MUP, together with its bound volatiles, induces puberty acceleration. Its activity is retained even when the volatiles have been removed either by organic extraction or competition displacement with a high-affinity ligand. 3. MUP-related hexapeptide also induces puberty acceleration in female mice. In contrast, the odorants bound to MUP do not exert this effect. 4. It is proposed that the vomeronasal organ contains receptors that recognize the short N-terminal consensus sequence, N-Glu-Glu-Ala-X-Ser (where X is a polar residue), common to both MUP and the hexapeptide.

Animals↗
PubMed1995

Pheromonally accelerated puberty is enhanced by previous experience of the same stimulus.

The influence of rearing conditions on pheromone-induced puberty acceleration was tested on Swiss mice. Litters were reared in one of three conditions: with either both parents, or with two females, or finally with two females in the presence of urinary pheromonal cues from adult males, which are known to induce puberty acceleration. Nine days after weaning the females were exposed to either prepubertal or adult male urine. In the groups reared with either both parents or with two females and the pheromonal cues from stranger males, females treated with adult male urine presented heavier uteri and more cornified vaginal smears than females reared in the same conditions but subsequently treated with prepubertal males urine. In the group reared simply with two females, the differences in both uterus weight and vaginal smears did not reach statistical significance. The data support the notion that early experience of pheromonal cues may influence the response to pheromones in a later period, even if the preweaning exposure to males had no direct influence on early signs of puberty onset.

Animals↗
PubMed1992

Pheromone binding to two rodent urinary proteins revealed by X-ray crystallography.

The principal protein excreted in male rat urine, urinary alpha 2-globulin and the homologous mouse protein, major urinary protein, have been well characterized, although their functions remain unclear. Male rat urine affects the behaviour and sexual response of female rats, leading to the proposal that rodent urinary proteins are responsible for binding pheromones and their subsequent release from drying urine. Urinary alpha 2-globulin is also involved in hyaline droplet nephropathy, an important toxicological syndrome in male rats resulting from exposure to a number of industrial chemicals and characterized by the accumulation of liganded urinary alpha 2-globulin in lysosomes in the kidney, followed by the induction of renal cancer. We now report the three-dimensional structures of mouse major urinary protein (at 2.4 A resolution) and rat urinary alpha 2-globulin (at 2.8 A resolution). The results corroborate the role of these proteins in pheromone transport and elaborate the structural basis of ligand binding.

Alpha-Globulins↗
PubMed1991

Crystallization of and preliminary X-ray data for the mouse major urinary protein and rat alpha-2u globulin.

Crystals of the mouse major urinary protein (MUP) and rat alpha-2u globulin (AMG) have been grown from solutions of polyethylene glycol 3350 and CdCl2, respectively. The crystals differ both in their morphologies and space groups but have very similar unit cell sizes. AMG crystallized in P2(1) (a = 56.6 A, b = 103.8 A, c = 62.7 A, beta = 95.1 degrees) with four subunits/asymmetric unit, while MUP gave crystals in P4(1)2(1)2 or P4(3)2(1)2 (a = 57.3 A, c = 109.9 A) with one subunit/asymmetric unit. Both crystal forms diffract beyond 2.8 A resolution.

Alpha-Globulins↗
PubMed1990

Ligand binding characteristics of homologous rat and mouse urinary proteins and pyrazine-binding protein of calf.

1. The binding affinities of three classes of homologous proteins, alpha 2u protein from rat urine, major urinary protein of mouse and pyrazine-binding protein of calf nasal mucosa have been determined for a panel of ligands. 2. Best ligands were low threshold odorants for man, but chemically unrelated. 3. The binding spectra of the homologous proteins were different.

Animals↗