15 research outputs found

    HmtDB, a genomic resource for mitochondrion-based human variability studies

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    HmtDB (http://www.hmtdb.uniba.it:8080/hmdb) is a open resource created to support population genetics and mitochondrial disease studies. The database hosts human mitochondrial genome sequences annotated with population and variability data, the latter being estimated through the application of the SiteVar software based on site-specific nucleotide and amino acid variability calculations. The annotations are manually curated thus adding value to the quality of the information provided to the end-user. Classifier tools implemented in HmtDB allow the prediction of the haplogroup for any human mitochondrial genome currently stored in HmtDB or externally submitted de novo by an end-user. Haplogroup definition is based on the Phylotree system. End-users accessing HmtDB are hence allowed to (i) browse the database through the use of a multi-criterion ‘query’ system; (ii) analyze their own human mitochondrial sequences via the ‘classify’ tool (for complete genomes) or by downloading the ‘fragment-classifier’ tool (for partial sequences); (iii) download multi-alignments with reference genomes as well as variability data

    CX3CR1 Regulates the Maintenance of KLRG1+ NK Cells into the Bone Marrow by Promoting Their Entry into Circulation

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    NK cell differentiation mainly occurs in the bone marrow (BM) where a critical role in the regulation of developing lymphocyte distribution is played by members of the chemokine receptor family. In mouse, the chemokine receptor CX3CR1 identifies a late stage of NK cell development characterized by decreased effector functions and expression of the inhibitory receptor KLRG1. The role of CX3CR1 in the regulation of differentiation and positioning of NK cell subsets in the BM is not known. In this study, we found that CX3CR1 deficiency leads to accumulation of KLRG1(+) NK cells in BM during steady-state conditions. The NK cell subset that expresses the receptor in wild-type mice was expanded in several tissues of CX3CR1-deficient mice, and NK cell degranulation in response to sensitive target cell stimulation was enhanced, suggesting a regulatory role of CX3CR1 in NK cell positioning and differentiation in BM. Indeed, the observed NK cell expansion was not due to altered turnover rate, whereas it was associated with preferential accumulation in the BM parenchyma. In addition, a role of CX3CR1 in NK cell trafficking from BM and spleen was evidenced also during inflammation, as CX3CR1-deficient NK cells were more prompt to exit the BM and did not decrease in spleen in response to polyinosinic-polycytidylic acid-promoted hepatitis. Overall, our results evidenced a relevant role of CX3CR1 in the regulation of NK cell subset exit from BM during homeostasis, and suggest that defect in the CX3CR1/CX3CL1 axis alters NK cell trafficking and functional response during inflammatory conditions

    CX3CR1 expression defines 2 KLRG1+ mouse NK-cell subsets with distinct functional properties and positioning in the bone marrow

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    During development in the bone marrow (BM), NK-cell positioning within specific niches can be influenced by expression of chemokine or adhesion receptors. We previously demonstrated that the maintenance in the BM of selected NK-cell subsets is regulated by the CXCR4/CXCL12 axis. In the present study, we showed that CX3CR1 is prevalently expressed on KLRG1(+) NK cells, a subset considered terminally differentiated. Two KLRG1(+) NK-cell populations endowed with distinct homing and functional features were defined according to CX3CR1 expression. In the BM, KLRG1(+)/CX3CR1(-) NK cells were mainly positioned into parenchyma, while KLRG1(+)/CX3CR1(+) NK cells exhibited reduced CXCR4 expression and were preferentially localized in the sinusoids. We also showed that alpha(4) integrin plays a pivotal role in the maintenance of NK cells in the BM sinusoids and that alpha(4) neutralization leads to strong reduction of BM KLRG1(+)/CX3CR1(+) NK cells. Moreover, we found that KLRG1(+)/CX3CR1(+) cells originate from KLRG1(+)/CX3CR1(-) NK-cell population and display impaired capability to produce IFN-gamma and to lyse YAC-1 target cells on cytokine stimulation. Altogether, our findings show that CX3CR1 represents a marker of a KLRG1(+) NK-cell population with unique properties that can irreversibly differentiate from the KLRG1(+)/CX3CR1(-) NK cells during steady state conditions. (Blood. 2011; 117(17): 4467-4475

    Multiple Myeloma Impairs Bone Marrow Localization of Effector Natural Killer Cells by Altering the Chemokine Microenvironment.

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    Natural killer (NK) cells are key innate immune effectors against multiple myeloma, their activity declining in multiple myeloma patients with disease progression. To identify the mechanisms underlying NK cell functional impairment, we characterized the distribution of functionally distinct NK cell subsets in the bone marrow of multiple myeloma-bearing mice. Herein we report that the number of KLRG1(-) NK cells endowed with potent effector function rapidly and selectively decreases in bone marrow during multiple myeloma growth, this correlating with decreased bone marrow NK cell degranulation in vivo. Altered NK cell subset distribution was dependent on skewed chemokine/chemokine receptor axes in the multiple myeloma microenvironment, with rapid downmodulation of the chemokine receptor CXCR3 on NK cells, increased CXCL9 and CXCL10, and decreased CXCL12 expression in bone marrow. Similar alterations in chemokine receptor/chemokine axes were observed in patients with multiple myeloma. Adoptive transfer experiments demonstrated that KLRG1(-) NK cell migration to the bone marrow was more efficient in healthy than multiple myeloma-bearing mice. Furthermore, bone marrow localization of transferred CXCR3-deficient NK cells with respect to wild type was enhanced in healthy and multiple myeloma-bearing mice, suggesting that CXCR3 restrains bone marrow NK cell trafficking. Our results indicate that multiple myeloma-promoted CXCR3 ligand upregulation together with CXCL12 downmodulation act as exit signals driving effector NK cells outside the bone marrow, thus weakening the antitumor immune response at the primary site of tumor growt

    Meat from wild ungulates: ensuring quality and hygiene of an increasing resource

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    Wild ungulate populations are increasing in Europe and Italy, with a consequent increase in culling rates and availability of their meats. Objectives of this review were to evaluate the trends of availability of meat from wild ungulates in Italy, to review the present knowledge on nutritional properties, sensorial characteristics, and hygiene problems of wild ungulate meat and to examine the critical steps that influence their hygiene and quality. Wild ungulate meat in Italy derives mainly from wild boar, roe deer and red deer and its availability has been increasing in the last decade. Total consumption of wild ungulate meat is low (0.1-0.3 kg per capita/year), but in some regions rises to significant levels, especially for hunters’ families (1.0-4.0 kg per capita/year). Wild ungulate meats generally have a low fat content, although with a certain variability associated with gender, hunting season, age and physiological conditions, and a favourable fatty acid composition. In general, they are darker, less tender and characterised by a more intense and peculiar flavour than meats from domestic ruminants. However, these properties also show a great inter- and intra-specific variability. Risks for the consumer associated with contaminants (heavy metals, radionuclides, organochlorine pesticides and polychlorinated biphenyls) and zoonoses are considered to be low. Critical steps from shooting in the field to the final marketing should be considered to ensure hygiene and quality of meats. Future research should focus on the variability of hunting modes, accuracy of shooting, field dressing and carcass processing, in order to understand how these practices influence the final microbiological and sensorial quality of wild ungulate meats

    Sequential or Combination Treatments as Rescue Therapies in Immunocompromised Patients with Persistent SARS-CoV-2 Infection in the Omicron Era: A Case Series

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    Prolonged SARS-CoV-2 infections are widely described in immunosuppressed patients, but safe and effective treatment strategies are lacking. We aimed to outline our approach to treating persistent COVID-19 in patients with immunosuppression from different causes. In this case series, we retrospectively enrolled all immunosuppressed patients with persistent SARS-CoV-2 infections treated at our centers between March 2022 and February 2023. Patients received different sequential or combination regimens, including antivirals (remdesivir, nirmatrelvir/ritonavir, or molnupiravir) and/or monoclonal antibodies (mAbs) (tixagevimab/cilgavimab or sotrovimab). The main outcome was a complete virological response (negative SARS-CoV-2 RT-PCR on nasopharyngeal swabs) at the end of treatment. Fifteen patients were included as follows: eleven (11/15; 73%) with hematological disease and four (4/15; 27%) with recently diagnosed HIV/AIDS infection. Six patients (6/15; 40%) received a single antiviral course, four patients (4/15; 27%) received an antiviral and mAbs sequentially, and two patients (13%) received three lines of treatment (a sequence of three antivirals or two antivirals and mAbs). A combination of two antivirals or one antiviral plus mAbs was administered in three cases (3/15, 20%). One patient died while still positive for SARS-CoV-2, while fourteen (14/15; 93%) tested negative within 16 days after the end of treatment. The median time to negativization since the last treatment was 2.5 days. Both sequential and combination regimens used in this study demonstrated high efficacy and safety in the high-risk group of immunosuppressed patients
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