Can the migration process influence the clinical expression of heroin use disorder in migrants to Italy?

BACKGROUND: For some time now, there has been a strong consensus that the migration process can influence the onset, course, development, outcome, and clinical aspects of psychiatric pathologies. METHODS: In this study, we have analyzed the influence of the migration process on the clinical expression of heroin use disorder (HUD). In a naturalistic case-control study, we compared, both at univariate and multivariate level, 30 migrant HUD (M-HUD) patients with 30 age/gender-matched Italian HUD (IT-HUD) patients. We also analyzed demographic data, drug addiction history, psychopathological symptoms, addictive behavior, and emotional reactivity to life events. RESULTS: Compared with IT-HUD pairs, at HUD Agonist Opioid Treatment, M-HUD patients were characterized by inadequate income and the presence of legal problems. They were more frequently at stage 3 of heroin addiction, with a concomitantly less frequent use of stimulants. Their age at the onset of heroin use was greater than that of subjects in the IT-HUD group. HUD post-traumatic stress disorder spectrum was present and was more severe in all M-HUD patients, but grief reactions and maladaptive behavior were the most discriminant traits. No differences were found in terms of addictive behaviors related to heroin craving or with respect to the severity/typology of psychopathology specific to HUD. CONCLUSIONS: The migratory process does not seem to be correlated with addictive behaviors or with psychopathology specific to HUD. It partly affects HUD history, and specifically correlates with emotional reactivity to loss and traumatic life events, so suggesting that in M-HUD individuals, the link between the migratory syndrome and HUD is very close.

Identifying the structure of the active sites of human recombinant prolidase.

In this paper we provide a detailed biochemical and structural characterization of the active site of recombinant human prolidase, a dimeric metalloenzyme, whose misfunctioning causes a recessive connective tissue disorder (prolidase deficiency) characterized by severe skin lesions, mental retardation and respiratory tract infections. It is known that the protein can host two metal ions in the active site of each constituent monomer. We prove that two different kinds of metals (Mn and Zn) can be simultaneously present in the protein active sites with the protein partially maintaining its enzymatic activity. Structural information extracted from X-ray absorption spectroscopy measurements have been used to yield a full reconstruction of the atomic environment around each one of the two monomeric active sites. In particular, as for the metal ion occupation configuration of the recombinant human prolidase, we have found that one of the two active sites is occupied by two Zn ions and the second one by one Zn and one Mn ion. In both dinuclear units a histidine residue is bound to a Zn ion.

In utero transplantation of adult bone marrow decreases perinatal lethality and rescues the bone phenotype in the knockin murine model for classical, dominant osteogenesis imperfecta.

Autosomal dominant osteogenesis imperfecta (OI) caused by glycine substitutions in type I collagen is a paradigmatic disorder for stem cell therapy. Bone marrow transplantation in OI children has produced a low engraftment rate, but surprisingly encouraging symptomatic improvements. In utero transplantation (IUT) may hold even more promise. However, systematic studies of both methods have so far been limited to a recessive mouse model. In this study, we evaluated intrauterine transplantation of adult bone marrow into heterozygous BrtlIV mice. Brtl is a knockin mouse with a classical glycine substitution in type I collagen [alpha1(I)-Gly349Cys], dominant trait transmission, and a phenotype resembling moderately severe and lethal OI. Adult bone marrow donor cells from enhanced green fluorescent protein (eGFP) transgenic mice engrafted in hematopoietic and nonhematopoietic tissues differentiated to trabecular and cortical bone cells and synthesized up to 20% of all type I collagen in the host bone. The transplantation eliminated the perinatal lethality of heterozygous BrtlIV mice. At 2 months of age, femora of treated Brtl mice had significant improvement in geometric parameters (P < .05) versus untreated Brtl mice, and their mechanical properties attained wild-type values. Our results suggest that the engrafted cells form bone with higher efficiency than the endogenous cells, supporting IUT as a promising approach for the treatment of genetic bone diseases.

A quantitative and qualitative method for direct 2-DE analysis of murine cartilage.

Direct 2-DE analysis of cartilage is difficult due to the high proteoglycan content. Proteoglycan removal before IEF may however cause the partial or total loss of specific proteins making this approach ineffective when quantitative data are required to investigate protein expression differences. Thus, we have developed a 2-DE method including passive rehydration loading that does not require sample pretreatment and allows direct protein expression studies in cartilage samples.

Differential expression of both extracellular and intracellular proteins is involved in the lethal or nonlethal phenotypic variation of BrtlIV, a murine model for osteogenesis imperfecta.

This study used proteomic and transcriptomic techniques to understand the molecular basis of the phenotypic variability in the bone disorder osteogenesis imperfecta (OI). Calvarial bone mRNA expression was evaluated by microarray, real-time, and comparative RT-PCR and the bone proteome profile was analyzed by 2-DE, MS, and immunoblotting in the OI murine model BrtlIV, which has either a moderate or a lethal OI outcome. Differential expression analysis showed significant changes for eight proteins. The expression of the ER stress-related protein Gadd153 was increased in lethal mice, whereas expression of the chaperone alphaB crystallin was increased in nonlethal mice, suggesting that the intracellular machinery is involved in the modulation of the OI phenotype. Furthermore, in lethal BrtlIV, the increased expression of the cartilaginous proteins Prelp, Bmp6, and Bmp7 and the lower expression of the bone matrix proteins matrilin 4, microfibril-associated glycoprotein 2, and thrombospondin 3 revealed that both a delay in skeletal development and an alteration in extracellular matrix composition influence OI outcomes. Differentially expressed proteins identified in this model offer a starting point for elucidating the molecular basis of phenotypic variability, a characteristic common to many genetic disorders. The first reference 2-DE map for murine calvarial tissue is also reported.

Human recombinant prolidase from eukaryotic and prokaryotic sources. Expression, purification, characterization and long-term stability studies.

Prolidase is a Mn(2+)-dependent dipeptidase that cleaves imidodipeptides containing C-terminal proline or hydroxyproline. In humans, a lack of prolidase activity causes prolidase deficiency, a rare autosomal recessive disease, characterized by a wide range of clinical outcomes, including severe skin lesions, mental retardation, and infections of the respiratory tract. In this study, recombinant prolidase was produced as a fusion protein with an N-terminal histidine tag in eukaryotic and prokaryotic hosts and purified in a single step using immobilized metal affinity chromatography. The enzyme was characterized in terms of activity against different substrates, in the presence of various bivalent ions, in the presence of the strong inhibitor Cbz-Pro, and at different temperatures and pHs. The recombinant enzyme with and without a tag showed properties mainly indistinguishable from those of the native prolidase from fibroblast lysate. The protein yield was higher from the prokaryotic source, and a detailed long-term stability study of this enzyme at 37 degrees C was therefore undertaken. For this analysis, an 'on-column' digestion of the N-terminal His tag by Factor Xa was performed. A positive effect of Mn(2+) and GSH in the incubation mixture and high stability of the untagged enzyme are reported. Poly(ethylene glycol) and glycerol had a stabilizing effect, the latter being the more effective. In addition, no significant degradation was detected after up to 6 days of incubation with cellular lysate. Generation of the prolidase in Escherichia coli, because of its high yield, stability, and similarity to native prolidase, appears to be the best approach for future structural studies and enzyme replacement therapy.

SP-A binds alpha1-antitrypsin in vitro and reduces the association rate constant for neutrophil elastase.

BACKGROUND: Alpha1-antitrypsin and surfactant protein-A (SP-A) are major lung defense proteins. With the hypothesis that SP-A could bind alpha1-antitrypsin, we designed a series of in vitro experiments aimed at investigating the nature and consequences of such an interaction. METHODS AND RESULTS: At an alpha1-antitrypsin:SP-A molar ratio of 1:1, the interaction resulted in a calcium-dependent decrease of 84.6% in the association rate constant of alpha1-antitrypsin for neutrophil elastase. The findings were similar when SP-A was coupled with the Z variant of alpha1-antitrypsin. The carbohydrate recognition domain of SP-A appeared to be a major determinant of the interaction, by recognizing alpha1-antitrypsin carbohydrate chains. However, binding of SP-A carbohydrate chains to the alpha1-antitrypsin amino acid backbone and interaction between carbohydrates of both proteins are also possible. Gel filtration chromatography and turnover per inactivation experiments indicated that one part of SP-A binds several molar parts of alpha1-antitrypsin. CONCLUSION: We conclude that the binding of SP-A to alpha1-antitrypsin results in a decrease of the inhibition of neutrophil elastase. This interaction could have potential implications in the physiologic regulation of alpha1-antitrypsin activity, in the pathogenesis of pulmonary emphysema, and in the defense against infectious agents.

N-benzyloxycarbonyl-L-proline: an in vitro and in vivo inhibitor of prolidase.

Prolidase deficiency (PD) is a recessive disorder of the connective tissue caused by mutations in the prolidase, a specific peptidase, cleaving the dipeptides with a C-terminal prolyl and hydroxyprolyl residue. PD is a complex syndrome characterized mainly by intractable skin lesions, recurrent respiratory infections and mental retardation. The relation between prolidase biological functions and the disease is still largely unknown. We studied the effect of a prolidase inhibitor, N-benzyloxycarbonyl-l-proline (Cbz-Pro), in vitro on prolidase from human fibroblasts and in vivo on murine erythrocytes prolidase. A 90% inhibition was detected incubating cellular extracts at 1:1 ratio of Gly-Pro substrate: Cbz-Pro inhibitor. Pulse experiments performed incubating human fibroblasts with 6 mM Cbz-Pro revealed that the inhibitor uptake was completed in about 1 min. The Cbz-Pro uptake was saturable and pH dependent. Long-term incubation of fibroblasts with Cbz-Pro caused mitochondria depolarization and increased cellular death as reported for long-term culture of fibroblasts from PD patients. An inhibitory effect of Cbz-Pro has also been shown in vivo. Our results demonstrated that Cbz-Pro is a potent inhibitor of prolidase in cultured fibroblasts and it can be used in vivo to better characterize the prolidase enzyme and further investigate PD physiopathology.

Characterization of a new PEPD allele causing prolidase deficiency in two unrelated patients: natural-occurrent mutations as a tool to investigate structure-function relationship.

Prolidase deficiency (PD) is a rare autosomal recessive disorder characterized mainly by skin lesions of the legs and feet, mental retardation, and respiratory infections. Mutations at the PEPD locus, located on chromosome 19, are responsible for this disease. We identified a new PEPD allele in two unrelated Portuguese PD patients by analyses of reverse transcribed PCR-amplified cDNA. We used SSCP analysis of seven overlapping fragments spanning the entire coding region of the gene and detected abnormal SSCP bands in two of them: PD3 (nt 425-743) and PD4 (nt 661-973). Direct sequencing of the mutant cDNA and genomic DNA revealed a new homozygous 3-bp deletion (Y231del) in both cases. Transient expression in PD fibroblasts of wild-type and mutant prolidase cDNA confirmed reduced activity of the construct carrying the 3-bp deletion. The mutation results in a loss of prolidase activity in skin fibroblasts. Intracellular accumulation of Gly-Pro dipeptide in long-term cultured fibroblasts was detected by capillary electrophoresis. The mutation falls in the alpha2 domain of the "pita bread" structure proposed for E. coli and human prolidase by Bazan et al. on the bases of their sequence homology with E. coli methionine aminopeptidase. Taking into account the effects of the described mutations on stability and activity of the enzyme, we propose the identification of three different functional regions.

Optimization of a capillary electrophoretic method to detect and quantify the Gly-Pro dipeptide in complex matrices from long term cultured prolidase deficiency fibroblasts.

A capillary electrophoresis (CE) method has been developed and optimized for the detection of Gly-Pro dipeptide in complex biological samples: medium, cell layer and matrix obtained from long term cultured human fibroblasts of control and prolidase deficiency patients. The influence of different detergents in the sample preparation and electrophoretic conditions were investigated. The method was validated for cellular extracts with respect to limits of detection and quantitation, precision, linearity, accuracy and robustness. The optimized method was applied to real samples and revealed a significant increase of intracellular Gly-Pro dipeptide in prolidase deficiency fibroblasts with respect to the control.

Mutation analysis of five new patients affected by prolidase deficiency: the lack of enzyme activity causes necrosis-like cell death in cultured fibroblasts.

Prolidase, a ubiquitously distributed dipeptidase, is involved in the latter stage of degradation of endogenous and dietary proteins and is particularly important in collagen catabolism. It hydrolyzes dipeptides containing proline or hydroxyproline at the C-terminal position. Mutations in the gene encoding for prolidase cause prolidase deficiency (PD), an autosomal recessive disorder mainly characterized by skin lesions, mental retardation and recurrent infectious. In this work we reported the identification of the molecular defect in five PD patients. Direct sequencing of PCR amplified genomic DNA showed a homozygous G>A transversion in two siblings leading to a G448R substitution. A heterozygous IVS11+1G>C transition causing the skipping of exon 11 and a null allele were detected in a third proband. In two unrelated patients, a homozygous IVS7-1G>A transversion was identified and shown to cause multiple alternative spliced transcripts. All the mutations result in loss of prolidase activity. Long-term cultured fibroblasts from these PD patients were used to develop an in vitro model that allowed investigation of the affected cells. Light and electron microscopy revealed that PD cells were more round and branched out than controls with increased cytosolic vacuolization, interruptions of the plasma membrane, mitochondria swelling, mitochondrial matrix and cristae modifications. JC-1 labeling showed decreased mitochondrial membrane potential. A significant intracellular accumulation of the Gly-Pro dipeptide was detected by capillary electrophoresis analysis. Our results provide the first evidence that absence of prolidase activity causes the activation of a necrosis-like cellular death, which could be responsible for the typical skin lesions in PD.