Trimers Conjugated to Fibrin Hydrogels Promote Salivary Gland Function.

New strategies for tissue engineering have great potential for restoring and revitalizing impaired tissues and organs, including the use of smart hydrogels that can be modified to enhance organization and functionality of the salivary glands. For instance, monomers of laminin-111 peptides chemically conjugated to fibrin hydrogel (L1pM-FH) promote cell cluster formation in vitro and salivary gland regeneration in vivo when compared with fibrin hydrogel (FH) alone; however, L1pM-FH produce only weak expression of acinar differentiation markers in vivo (e.g., aquaporin-5 and transmembrane protein 16). Since previous studies demonstrated that a greater impact can be achieved when trimeric forms were used as compared with monomeric or dimeric forms, we investigated the extent to which trimers of laminin-111 chemically conjugated to FH (L1pT-FH) can increase the expression of acinar differentiation markers and elevate saliva secretion. In vitro studies using Par-C10 acinar cells demonstrated that when compared with L1pM-FH, L1pT-FH induced similar levels of acinar-like cell clustering, polarization, lumen formation, and calcium signaling. To assess the performance of the trimeric complex in vivo, we compared the ability of L1pM-FH and L1pT-FH to increase acinar differentiation markers and restore saliva flow rate in a salivary gland wound model of C57BL/6 mice. Our results show that L1pT-FH applied to wounded mice significantly improved the expression of the acinar differentiation markers and saliva secretion when compared with the monomeric form. Together, these positive effects of L1pT-FH warrant its future testing in additional models of hyposalivation with the ultimate goal of applying this technology in humans.

P2Y2 R deletion ameliorates sialadenitis in IL-14α-transgenic mice.

OBJECTIVE: Interleukin-14α-transgenic (IL-14αTG) mice develop an autoimmune exocrinopathy with characteristics similar to Sjögren's syndrome, including sialadenitis and hyposalivation. The P2Y2 receptor (P2Y2 R) for extracellular ATP and UTP is upregulated during salivary gland inflammation (i.e., sialadenitis) where it regulates numerous inflammatory responses. This study investigated the role of P2Y2 Rs in autoimmune sialadenitis in the IL-14αTG mouse model of Sjögren's syndrome. MATERIALS AND METHODS: IL-14αTG mice were bred with P2Y2 R-/- mice to generate IL-14αTG × P2Y2 R-/- mice. P2Y2 R expression, lymphocytic focus scores, B- and T-cell accumulation, and lymphotoxin-α expression were evaluated in the submandibular glands (SMG) along with carbachol-stimulated saliva secretion in IL-14αTG, IL-14αTG × P2Y2 R-/- , and C57BL/6 control mice at 9 and 12 months of age. RESULTS: Genetic ablation of P2Y2 Rs in IL-14αTG mice significantly reduced B and T lymphocyte infiltration of SMGs. However, reduced sialadenitis did not restore saliva secretion in IL-14αTG × P2Y2 R-/- mice. Decreased sialadenitis in IL-14αTG × P2Y2 R-/- mice correlated with decreased lymphotoxin-α levels, a critical proinflammatory cytokine associated with autoimmune pathology in IL-14αTG mice. CONCLUSIONS: The results of this study suggest that P2Y2 Rs contribute to the development of salivary gland inflammation in IL-14αTG mice and may also contribute to autoimmune sialadenitis in humans.

A 37-year-old Menkes disease patient-Residual ATP7A activity and early copper administration as key factors in beneficial treatment.

Menkes disease (MD) is a lethal disorder characterized by severe neurological symptoms and connective tissue abnormalities; and results from malfunctioning of cuproenzymes, which cannot receive copper due to a defective intracellular copper transporting protein, ATP7A. Early parenteral copper-histidine supplementation may modify disease progression substantially but beneficial effects of long-term treatment have been recorded in only a few patients. Here we report on the eldest surviving MD patient (37 years) receiving early-onset and long-term copper treatment. He has few neurological symptoms without connective tissue disturbances; and a missense ATP7A variant, p.(Pro852Leu), which results in impaired protein trafficking while the copper transport function is spared. These findings suggest that some cuproenzymes maintain their function when sufficient copper is provided to the cells; and underline the importance of early initiated copper treatment, efficiency of which is likely to be dependent on the mutant ATP7A function.

Signals regulating trafficking of Menkes (MNK; ATP7A) copper-translocating P-type ATPase in polarized MDCK cells.

The Menkes protein (MNK; ATP7A) functions as a transmembrane copper-translocating P-type ATPase and plays a vital role in systemic copper absorption in the gut and copper reabsorption in the kidney. Polarized epithelial cells such as Madin-Darby canine kidney (MDCK) cells are a physiologically relevant model for systemic copper absorption and reabsorption in vivo. In this study, cultured MDCK cells were used to characterize MNK trafficking and enabled the identification of signaling motifs required to target the protein to specific membranes. Using confocal laser scanning microscopy and surface biotinylation we demonstrate that MNK relocalizes from the Golgi to the basolateral (BL) membrane under elevated copper conditions. As previously shown in nonpolarized cells, the metal binding sites in the NH2-terminal domain of MNK were found to be required for copper-regulated trafficking from the Golgi to the plasma membrane. These data provide molecular evidence that is consistent with the presumed role of this protein in systemic copper absorption in the gut and reabsorption in the kidney. Using site-directed mutagenesis, we identified a dileucine motif proximal to the COOH terminus of MNK that was critical for correctly targeting the protein to the BL membrane and a putative PDZ target motif that was required for localization at the BL membrane in elevated copper.

Function and regulation of the mammalian copper-transporting ATPases: insights from biochemical and cell biological approaches.

Copper is an essential trace element that plays a very important role in cell physiology. In humans, disruption of normal copper homeostasis leads to severe disorders, such as Menkes disease and Wilson's disease. Recent genetic, cell biological, and biochemical studies have begun to dissect the molecular mechanisms involved in transmembrane transport and intracellular distribution of copper in mammalian cells. In this review, we summarize the advances that have been made in understanding of structure, function, and regulation of the key human copper transporters, the Menkes disease and Wilson's disease proteins.

The Menkes copper transporter is required for the activation of tyrosinase.

Menkes disease is an X-linked recessive copper deficiency disorder caused by mutations in the ATP7A (MNK) gene. The MNK gene encodes a copper-transporting P-type ATPase, MNK, which is localized predominantly in the trans-Golgi network (TGN). The MNK protein relocates to the plasma membrane in cells exposed to elevated copper where it functions in copper efflux. A role for MNK at the TGN in mammalian cells has not been demonstrated. In this study, we investigated whether the MNK protein is required for the activity of tyrosinase, a copper-dependent enzyme involved in melanogenesis that is synthesized within the secretory pathway. We demonstrate that recombinant tyrosinase expressed in immortalized Menkes fibroblast cell lines was inactive, whereas in normal fibroblasts known to express MNK protein there was substantial tyrosinase activity. Co-expression of the Menkes protein and tyrosinase from plasmid constructs in Menkes fibroblasts led to the activation of tyrosinase and melanogenesis. This MNK-dependent activation of tyrosinase was impaired by the chelation of copper in the medium of cells and after mutation of the invariant phosphorylation site at aspartic acid residue 1044 of MNK. Collectively, these findings suggest that the MNK protein transports copper into the secretory pathway of mammalian cells to activate copper-dependent enzymes and reveal a second copper transport role for MNK in mammalian cells. These findings describe a single cell-based system that allows both the copper transport and trafficking functions of MNK to be studied. This study also contributes to our understanding of the molecular basis of pigmentation in mammalian cells.

[Peripheral blood stem cell collection in pediatric oncohematology. Experience with patients weighing less than 15 kg]. / Raccolta di cellule staminali periferiche in oncoematologia pediatrica. Esperienza su soggetti di peso inferiore a 15 kg.

BACKGROUND: Leukapheresis for peripheral blood stem cell collection is increasingly being carried out in pediatric cancer patients. Aim of this study was to report experience of the Padua Apheresis Unit on a series of children weighting < 15 kg who have undergone such an apheresis procedure. METHODS: This retrospective study includes 15 pediatric patients affected with various malignancies (neuroblastoma: 7; acute myelogenous leukemia: 3; rhabdomyosarcoma: 2; PNET: 1; retinoblastoma: 1; Burkitt's lymphoma: 1) collecting peripheral blood stem cells by a Cobe Spectra blood cell separator. Main procedure parameters, including vascular access, leukapheresis duration, blood flow rate, processed blood volumes, side effects, mononuclear and CD34+ cell yields, have been registered. RESULTS: Altogether 22 sessions have been carried out, by processing a mean of 2.8 blood volumes. No leukapheresis related complications have been recorded, such as hypotension, hypocalcemia and hypothermia. Noteworthy, in 4 procedures two or more peripheral venipunctures have been performed to ensure an adequate blood flow. CONCLUSIONS: Leukapheresis for peripheral blood stem cell collection can be safely and efficaciously carried out in pediatric patients, even weighing < 15 kg, on the condition that certain aspects of apheresis practice in children (vascular access, volume shifts, anticoagulation, side effects) are carefully considered.

Interferon treatment of chronic hepatitis C in patients cured of pediatric malignancies.

BACKGROUND AND OBJECTIVE: Chronic hepatitis C was a frequent complication in patients treated for malignancy until the introduction of anti-HCV screening tests for blood donors. The association between chronic hepatitis C and progression to cirrhosis and hepatocellular carcinoma has been reported in about 20% and 5% of patients, respectively, within 20-30 years of infection. In adult patients, interferon has proved to be effective in decreasing the abnormal values of transaminases and the level of HCV viremia. Our purpose was to assess efficacy of and tolerance to interferon in a group of young patients who had acquired HCV infection during a period of chemotherapy. DESIGN AND METHODS: Interferon-a (IFN) was administered to 26 adolescents and young adults (13 males, age range 17-36 years; median age 24) with chronic hepatitis C, including 4 with hepatitis B virus co-infection, who had been treated for leukemia or solid tumor 5 to 19 years before joining this trial. Patients were treated with natural IFN alpha at a dose of 4 MU/m(2) thrice weekly for 12 months and followed up for another 6 months thereafter. RESULTS: Nine patients stopped treatment during the first 6 months because of side effects (2 cases) or lack of response. At the end of the trial, 8 (31%) cases had responded, with alanine amino-transferase normalization and clearance of hepatitis C virus (HCV) RNA. A sustained response was only documented in 15% of cases, however, irrespective of any hepatitis B virus co-infection. The 2 patients with HCV genotype 2 were both responders, whereas only 8% of those with genotype 1 responded. INTERPRETATION AND CONCLUSIONS: These data show that the efficacy of IFN in this series of young patients is similar to that reported for otherwise healthy adults with hepatitis C. Patients with genotype 2 are strong candidates for IFN treatment while other therapeutic strategies should be designed for patients with HCV genotype 1.

The Menkes protein (ATP7A; MNK) cycles via the plasma membrane both in basal and elevated extracellular copper using a C-terminal di-leucine endocytic signal.

Menkes disease is an X-linked recessive copper deficiency disorder caused by mutations in the ATP7A ( MNK ) gene which encodes a copper transporting P-type ATPase (MNK). MNK is normally localized pre- dominantly in the trans -Golgi network (TGN); however, when cells are exposed to excessive copper it is rapidly relocalized to the plasma membrane where it functions in copper efflux. In this study, the c-myc epitope was introduced within the loop connecting the first and second transmembrane regions of MNK. This myc epitope allowed detection of the protein at the surface of living cells and provided the first experimental evidence supporting the common topological model. In cells stably expressing the tagged MNK protein (MNK-tag), extracellular antibodies were internalized to the perinuclear region, indicating that MNK-tag at the TGN constitutively cycles via the plasma membrane in basal copper conditions. Under elevated copper conditions, MNK-tag was recruited to the plasma membrane; however, internalization of MNK-tag was not inhibited and the protein continued to recycle through cyto- plasmic membrane compartments. These findings suggest that copper stimulates exocytic movement of MNK to the plasma membrane rather than reducing MNK retrieval and indicate that MNK may remove copper from the cytoplasm by transporting copper into the vesicles through which it cycles. Newly internalized MNK-tag and transferrin were found to co-localize, suggesting that MNK-tag follows a clathrin-coated pit/endosomal pathway into cells. Mutation of the di-leucine, L1487 L1488, prevented uptake of anti-myc antibodies in both basal and elevated copper conditions, thereby identifying this sequence as an endocytic signal for MNK. Analysis of the effects of the di-leucine mutation in elevated copper provided further support for copper-stimulated exocytic movement of MNK from the TGN to the plasma membrane.

Functional analysis of the N-terminal CXXC metal-binding motifs in the human Menkes copper-transporting P-type ATPase expressed in cultured mammalian cells.

The Menkes protein (MNK) is a copper-transporting P-type ATPase, which has six highly conserved metal-binding sites, GMTCXXC, at the N terminus. The metal-binding sites may be involved in MNK trafficking and/or copper-translocating activity. In this study, we report the detailed functional analysis in mammalian cells of recombinant human MNK and its mutants with various metal-binding sites altered by site-directed mutagenesis. The results of the study, both in vitro and in vivo, provide evidence that the metal-binding sites of MNK are not essential for the ATP-dependent copper-translocating activity of MNK. Moreover, metal-binding site mutations, which resulted in a loss of ability of MNK to traffick to the plasma membrane, produced a copper hyperaccumulating phenotype. Using an in vitro vesicle assay, we demonstrated that the apparent K(m) and V(max) values for the wild type MNK and its mutants were not significantly different. The results of this study suggest that copper-translocating activity of MNK and its copper-induced relocalization to the plasma membrane represent a well coordinated copper homeostasis system. It is proposed that mutations in MNK which alter either its catalytic activity or/and ability to traffick can be the cause of Menkes disease.

A C-terminal di-leucine is required for localization of the Menkes protein in the trans-Golgi network.

The human X-linked recessive disorder of copper metabolism, Menkes disease, is caused by a defect in the MNK ( ATP7A ) gene which encodes a transmembrane copper-transporting P-type ATPase (MNK). MNK is an important component of the mammalian copper transport pathway, and previous studies in cultured cells have localized MNK to the final compartment of the Golgi apparatus, the trans -Golgi network (TGN). At this location, MNK is predicted to supply copper to copper-dependent enzymes as they migrate through the secretory pathway. However, under conditions of elevated extracellular copper, the MNK protein undergoes a rapid relocalization to the plasma membrane where it functions in the efflux of copper from cells. In this study, three di-leucine motifs and a cluster of four acidic amino acids within the C-terminal region of MNK were investigated as candidate signals necessary for steady-state TGN localization. In vitro mutagenesis of the human MNK cDNA and immunofluorescence detection of mutant forms of MNK expressed in cultured cells demonstrated that the di-leucine, L1487L1488, was essential for localization of MNK within the TGN, but not for copper efflux. We suggest that this di-leucine motif is a putative endocytic targeting motif necessary for the retrieval of MNK from the plasma membrane to the TGN. Our data, along with the recent demonstration that the third transmembrane region of MNK functions as a TGN targeting signal, suggests that MNK localization to the TGN may be a two-step process involving TGN retention via the transmembrane region, and recycling to this compartment from the plasma membrane via the L1487L1488 motif.

Correction of the copper transport defect of Menkes patient fibroblasts by expression of the Menkes and Wilson ATPases.

Menkes' disease is a fatal, X-linked, copper deficiency disorder that results from defective copper efflux from intestinal cells and inadequate copper delivery to other tissues, leading to deficiencies of critical copper-dependent enzymes. Wilson's disease is an autosomally inherited, copper toxicosis disorder resulting from defective biliary excretion of copper, which leads to copper accumulation in the liver. The ATP7A and ATP7B genes that are defective in patients with Menkes' and Wilson's diseases, respectively, encode transmembrane, P-type ATPase proteins (ATP7A or MNK and ATP7B or WND, respectively) that function to translocate copper across cellular membranes. In this study, the cDNAs derived from a normal human ATP7A gene and the murine ATP7B homologue, Atp7b, were separately transfected into an immortalized fibroblast cell line obtained from a Menkes' disease patient. Both MNK and WND expressed from plasmid constructs were able to correct the copper accumulation and copper retention phenotype of these cells. However, the two proteins responded differently to elevated extracellular copper levels. Although MNK showed copper-induced trafficking from the trans-Golgi network to the plasma membrane, in the same cell line the intracellular location of WND did not appear to be affected by elevated copper.

Autologous bone marrow transplantation for childhood acute lymphoblastic leukaemia in Italy. AIEOP/FONOP-TMO Group. Italian Association of Paediatric Haemato-Oncology.

From January 1984 to December 1994, ABMT was performed on 154 children (101 males, 53 females; median age 10, range 3-21 years) with ALL and registered for BMT by the AIEOP (Italian Association of Paediatric Haemato-Oncology). All patients were in CR: 98 were in 2nd CR and 56 were in >2nd CR. Fifteen children (9.7%) died of transplant-related mortality. Ninety-five patients (61.6%) relapsed at a median of 5 (range 1-42) months after ABMT. The 8-year EFS according to pre-BMT status was 34.6% (s.e. 4.9) for 2nd CR patients and 10.6% (s.e. 5.6) for patients in >2nd CR. By univariate analysis, site of relapse (isolated extramedullary (IE) vs BM: EFS = 68.5% vs 18.2%; P < 0.0001) and TBI containing regimen (TBI vs no TBI: EFS = 48.1 vs 15.4%; P = 0.0023) were significant factors for 2nd CR patients. When the 2nd CR subset with BM involvement was analysed, TBI became insignificant (EFS = 25.4 vs 11.8%). No factors influenced EFS in patients in >2nd CR. By multivariate analysis, site of relapse was the only significant factor in 2nd CR patients (P < 0.0001). In conclusion, ABMT is an effective treatment after one early IE relapse. Few patients can be rescued after BM relapse.

Collection of peripheral blood stem cells in pediatric patients: a concise review on technical aspects.

Peripheral blood stem cells (PBSC) are now routinely collected for use as hematopoietic support after high-dose chemotherapy for various malignancies. Nevertheless, few data are still available on PBSC collection in pediatric patients, owing to technical problems associated with the leukapheresis procedure in children. This paper briefly summarizes current knowledge about some technical aspects of pediatric leukapheresis for PBSC collection, according to the review of the literature and our personal experience on 60 procedures performed in 36 children affected with various malignancies. Technical issues include venous access, risk of volume shift due to exceeding extracorporeal circulation, and anticoagulation, that can induce severe side-effects. Moreover, criteria for optimizing the PBSC harvesting procedure in children, in particular the correct timing of leukapheresis, are discussed.

Peripheral blood stem cell collection and transplantation in paediatric malignancies: a monocentric experience.

Thirty-seven patients underwent peripheral blood stem cell (PBSC) collection from May 1994 to May 1997. Twenty-five were males and 12 were females, the median age at collection was 11.5 years (range 1-27.4) and the median weight was 38 kg (range 9-80). As mobilising chemotherapy, cyclophosphamide, etoposide, doxorubicin and cytosine arabinoside were the drugs most frequently used in association with G-CSF for a total of 47 courses. Sixty-one aphereses were performed with a median collection of CD34+ and CFU-GM cells/kg of 3.6 x 10(6) (range 0.6-31.8) and 24.4 x 10(4) (range 0.1-1260), respectively. Minimal residual disease (MRD) was found in five of the 30 investigated aphereses. Twenty-one of the 37 patients underwent high-dose chemotherapy with autologous stem cell rescue: in seven the stem cell source was peripheral blood and bone marrow. The median duration of hospitalization was 18 days for the PBSC group and 23 days for the PBSC/ABMT group. Overall survival was 78.7% at a median follow-up of 18 months (range 2-31) and the DFS was 52% without difference depending on stem cell source. Compared to a historical group of ABMT patients, the PBSC group showed a statistical advantage in terms of neutrophils and platelet engraftment, blood and platelet requirements, and length of hospitalization. PBSC collection is a feasible procedure also in the paediatric setting providing that vascular access is adequate. As already reported, PBSC transplant results in faster engraftment and shorter hospitalization that could allow a better utilization of health financial resources. The question whether the source of stem cells could influence transplant outcome would require a prospective randomised study.

Baffling and Shielding System for a Millimeter-Wave balloonborne Telescope.

We describe a balloonborne telescope devoted to millimeter observations of diffuse sky radiation and optimized with a custom set of baffles and shields. The basic idea of the shield design is to shape the surfaces as roof mirrors to redirect the stray radiation in the opposite direction of incidence. The baffles are used to stop radiation close to the field of view. In this way we are able to avoid most of the unwanted radiation. We successfully operated this telescope (ARGO) during two flights, in 1989 and 1993, while detecting the faint structures of the cosmic microwave background at degree scale.

Chronic hepatitis C virus infection after treatment for pediatric malignancy.

Sera of 658 patients who had completed treatment for pediatric malignancy were analyzed by a second-generation enzyme-linked immunosorbent assay and recombinant immunoblot assay test to assess the prevalence of hepatitis C virus (HCV)-seropositivity. All HCV-seropositive patients underwent detailed clinical, laboratory, virologic, and histologic study to analyze the course of HCV infection. One hundred seventeen of the 658 patients (17.8%) were positive for HCV infection markers. Among the 117 anti-HCV+ patients, 41 (35%) were also positive for markers of hepatitis B virus infection with or without delta virus infection markers, 91 (77.8%) had previously received blood product transfusions, and 25 (21.4%) showed a normal alanine aminotransferase (ALT) level during the last 5-year follow-up (11 of them never had abnormal ALT levels). The remaining 92 patients showed ALT levels higher than the upper limit of normal range. Eighty-one of 117 (70%) anti-HCV+ patients were HCV-RNA+, with genotype 1b being present in most patients (54%). In univariate analysis, no risk factor for chronic liver disease was statistically significant. In this study, the prevalence of HCV infection was high in patients who were treated for a childhood malignancy. In about 20% of anti-HCV+ patients, routes other than blood transfusions are to be considered in the epidemiology of HCV infection. After a 14-year median follow-up, chronic liver disease of anti-HCV+ positive patients did not show progression to liver failure.