Pulmonary Langerhans Cell Histiocytosis and Lymphangioleiomyomatosis Have Circulating Cells With Loss of Heterozygosity of the TSC2 Gene.

BACKGROUND: Lymphangioleiomyomatosis (LAM) and pulmonary Langerhans cell histiocytosis (PLCH) are cystic lung diseases in which a neoplastic cell is thought to be responsible for disease pathogenesis. The neoplastic LAM cell has mutations in the TSC genes, TSC1 or TSC2, whereas the neoplastic PLCH cell may have mutations in several genes (eg, BRAF, NRAS, MAP2K1). These mutations are not specific for PLCH and have been described in multiple cancers. TSC1 or TSC2 mutations and loss of heterozygosity (LOH) have also been described in cancers. RESEARCH QUESTION: Is TSC2 LOH specific to LAM or is it also found in PLCH? STUDY DESIGN AND METHODS: We recruited patients with LAM (n = 53) and healthy volunteers (n = 22) and compared the presence of cells with TSC2 LOH with patients with PLCH (n = 12). Blood and urine samples were collected for analysis. Fluorescence-activated cell sorting (FACS) was used to identify subpopulations of cells from blood and urine samples. We isolated CD45-CD235a-, CD45-CD235a+, and CD45+CD235a- cells from blood after density gradient separation. Cells were screened for TSC2 LOH at five microsatellites markers (ie, kg8, D16S3395, D16S3024, D16S521, D16S291). We obtained four cell subpopulations from urine (ie, CD44v6+CD9+, CD44v6+CD9-, CD44v6-CD9+, CD44v6-CD9-). RESULTS: Using FACS, cells were isolated from blood and urine from patients with PLCH that showed TSC2 LOH. Healthy volunteers did not have cells with TSC2 LOH. As a control, cells isolated from blood and urine from patients with LAM gave results similar to those reported previously. These data show that TSC2 LOH is found in patients with cystic lung diseases with potential neoplastic characteristics, and in patients with cancer. INTERPRETATION: The presence of TSC2 LOH in circulating cells is not specific for LAM. The data suggest that chromosomal abnormalities affecting the TSC2 gene are found in other diseases associated with cells having cancer-like neoplastic cells.

Extracellular MicroRNA Signature of Human Helper T Cell Subsets in Health and Autoimmunity.

Upon T cell receptor stimulation, CD4+ T helper (Th) lymphocytes release extracellular vesicles (EVs) containing microRNAs. However, no data are available on whether human CD4+ T cell subsets release EVs containing different pattern of microRNAs. The present work aimed at filling this gap by assessing the microRNA content in EVs released upon in vitro T cell receptor stimulation of Th1, Th17, and T regulatory (Treg) cells. Our results indicate that EVs released by Treg cells are significantly different compared with those released by the other subsets. In particular, miR-146a-5p, miR-150-5p, and miR-21-5p are enriched, whereas miR-106a-5p, miR-155-5p, and miR-19a-3p are depleted in Treg-derived EVs. The in vitro identified EV-associated microRNA signature was increased in serum of autoimmune patients with psoriasis and returned to healthy levels upon effective treatment with etanercept, a biological drug targeting the TNF pathway and suppressing inflammation. Moreover, Gene Set Enrichment Analysis showed an over-representation of genes relevant for T cell activation, such as CD40L, IRAK1, IRAK2, STAT1, and c-Myb in the list of validated targets of Treg-derived EV miRNAs. At functional level, Treg-derived (but not Th1/Th17-derived) EVs inhibited CD4+ T cell proliferation and suppressed two relevant targets of miR-146a-5p: STAT1 and IRAK2. In conclusion, our work identified the miRNAs specifically released by different human CD4+ T cell subsets and started to unveil the potential use of their quantity in human serum to mark the pathological elicitation of these cells in vivo and their biological effect in cell to cell communication during the adaptive immune response.

Sirolimus Therapy for Patients With Lymphangioleiomyomatosis Leads to Loss of Chylous Ascites and Circulating LAM Cells.

A young woman received a diagnosis of abdominal, sporadic lymphangioleiomyomatosis (LAM) and multiple abdominal lymphangioleiomyomas and was referred for recurrent chylous ascites responding only to a fat-free diet. On admission, pulmonary function test (PFT) results showed a moderate reduction in the transfer factor for carbon monoxide with normal exercise performance. The serum vascular endothelial growth factor D (VEGF-D) level was 2,209 pg/mL. DNA sequences, amplified at loci kg8, D16S3395, D16S3024, D16S521, and D16S291 on chromosome 16p13.3, showed a loss of heterozygosity (LOH) only for kg8. Fat-free total parenteral nutrition in association with sirolimus (2 mg po daily) was initiated. Serum sirolimus levels were maintained at concentrations between 5 and 15 ng/mL. After 1 month, reintroduction of a low-fat oral feeding was achieved without recurrence of ascites. PFT results were stable. Interestingly, clinical improvement was associated with a reduction in the VEGF-D serum level (1,558 pg/mL). LOH at the kg8 biomarker in blood LAM cells was no longer detected.

Intracellular modulation, extracellular disposal and serum increase of MiR-150 mark lymphocyte activation.

Activated lymphocytes release nano-sized vesicles (exosomes) containing microRNAs that can be monitored in the bloodstream. We asked whether elicitation of immune responses is followed by release of lymphocyte-specific microRNAs. We found that, upon activation in vitro, human and mouse lymphocytes down-modulate intracellular miR-150 and accumulate it in exosomes. In vivo, miR-150 levels increased significantly in serum of humans immunized with flu vaccines and in mice immunized with ovalbumin, and this increase correlated with elevation of antibody titers. Immunization of immune-deficient mice, lacking MHCII, resulted neither in antibody production nor in elevation of circulating miR-150. This study provides proof of concept that serum microRNAs can be detected, with minimally invasive procedure, as biomarkers of vaccination and more in general of adaptive immune responses. Furthermore, the prompt reduction of intracellular level of miR-150, a key regulator of mRNAs critical for lymphocyte differentiation and functions, linked to its release in the external milieu suggests that the selective extracellular disposal of microRNAs can be a rapid way to regulate gene expression during lymphocyte activation.

Selective and potent agonists and antagonists for investigating the role of mouse oxytocin receptors.

The neuropeptides oxytocin (OT) and vasopressin (AVP) have been shown to play a central role in social behaviors; as a consequence, they have been recognized as potential drugs to treat neurodevelopmental and psychiatric disorders characterized by impaired social interactions. However, despite the basic and preclinical relevance of mouse strains carrying genetic alterations in the OT/AVP systems to basic and preclinical translational neuroscience, the pharmacological profile of mouse OT/AVP receptor subtypes has not been fully characterized. To fill in this gap, we have characterized a number of OT and AVP agonists and antagonists at three murine OT/AVP receptors expressed in the nervous system as follows: the oxytocin (mOTR) and vasopressin V1a (mV1aR) and V1b (mV1bR) subtypes. These three receptors were transiently expressed in vitro for binding and intracellular signaling assays, and then a homology model of the mOTR structure was constructed to investigate how its molecular features compare with human and rat OTR orthologs. Our data indicate that the selectivity profile of the natural ligands, OT and AVP, is conserved in humans, rats, and mice. Furthermore, we found that the synthetic peptide [Thr(4)Gly(7)]OT (TGOT) is remarkably selective for the mOTR and, like the endogenous OT ligand, activates Gq and Gi and recruits ß-arrestins. Finally, we report three antagonists that exhibit remarkably high affinities and selectivities at mOTRs. These highly selective pharmacological tools will contribute to the investigation of the specific physiologic and pathologic roles of mOTR for the development of selective OT-based therapeutics.

Pharmacologic rescue of impaired cognitive flexibility, social deficits, increased aggression, and seizure susceptibility in oxytocin receptor null mice: a neurobehavioral model of autism.

BACKGROUND: Oxytocin (OT) has been suggested as a treatment to improve social behavior in autistic patients. Accordingly, the OT (Oxt(-/-)) and the OT receptor null mice (Oxtr(-/-)) display autistic-like deficits in social behavior, increased aggression, and reduced ultrasonic vocalization. METHODS: Oxtr(-/-) mice were characterized for general health, sociability, social novelty, cognitive flexibility, aggression, and seizure susceptibility. Because vasopressin (AVP) and OT cooperate in controlling social behavior, learning, and aggression, they were tested for possible rescue of the impaired behaviors. Primary hyppocampal cultures from Oxtr(+/+) and Oxtr(-/-) mouse embryos were established to investigate the balance between gamma-aminobutyric acid (GABA) and glutamate synapses and the expression levels of OT and AVP (V1a) receptors were determined by autoradiography. RESULTS: Oxtr(-/-) mice display two additional, highly relevant, phenotypic characteristics: 1) a resistance to change in a learned pattern of behavior, comparable to restricted interests and repetitive behavior in autism, and 2) an increased susceptibility to seizures, a frequent and clinically relevant symptom of autism. We also show that intracerebral administration of both OT and AVP lowers aggression and fully reverts social and learning defects by acting on V1a receptors and that seizure susceptibility is antagonized by peripherally administered OT. Finally, we detect a decreased ratio of GABA-ergic versus total presynapses in hippocampal neurons of Oxtr(-/-) mice. CONCLUSIONS: Autistic-like symptoms are rescued on administration of AVP and OT to young Oxtr(-/-) adult animals. The Oxtr(-/-) mouse is thus instrumental to investigate the neurochemical and synaptic abnormalities underlying autistic-like disturbances and to test new strategies of pharmacologic intervention.

Dual modulation of inward rectifier potassium currents in olfactory neuronal cells by promiscuous G protein coupling of the oxytocin receptor.

Oxytocin receptor is a seven transmembrane receptor widely expressed in the CNS that triggers G(i) or G(q) protein-mediated signaling cascades leading to the regulation of a variety of neuroendocrine and cognitive functions. We decided to investigate whether and how the promiscuous receptor/G protein coupling affects neuronal excitability. As an experimental model, we used the immortalized gonadotropin-releasing hormone-positive GN11 cell line displaying the features of immature, migrating olfactory neurons. Using RT-PCR analysis, we detected the presence of oxytocin receptors whose stimulation by oxytocin led to the accumulation of inositol phosphates and to the inhibition of cell proliferation, and the expression of several inward rectifier (IR) K+ channel subtypes. Moreover, electrophysiological and pharmacological inspections using whole-cell patch-clamp recordings evidenced that in GN11 cells, IR channel subtypes are responsive to oxytocin. In particular, we found that: (i) peptide activation of receptor either inhibited or stimulated IR conductances, and (ii) IR current inhibition was mediated by a pertussis toxin-resistant G protein presumably of the G(q/11) subtype, and by phospholipase C, whereas IR current activation was achieved via receptor coupling to a pertussis toxin-sensitive G(i/o) protein. The findings suggest that neuronal excitability might be tuned by a single peptide receptor that mediates opposing effects on distinct K+ channels through the promiscuous coupling to different G proteins.

New macrocyclic amines showing activity as HIV entry inhibitors against wild type and multi-drug resistant viruses.

Considering as a lead molecule the chemokine CXCR4 receptor antagonist AMD-3100, which shows significant anti-HIV activity in vitro and in vivo, we investigated a series of structurally related macrocyclic polyamines incorporating o,o'-phenanthroline or 2,2'-bipyridyl scaffolds as potential antiviral agents with lower toxicity and increased activity against both wild type X4-tropic and dual tropic HIV strains. The antiviral activity of these compounds was evaluated by susceptibility assays in PBMC (Peripheral Blood Mononuclear Cells) and compared to that of AMD-3100. The newly investigated compounds showed IC(50)s values in the low micromolar range and significantly inhibited the viral replication of wild type X4-tropic isolate and dual tropic strains. These macrocyclic polyamines constitute a promising class of HIV entry inhibitors.

Analysis of the env V3 sequences obtained from patients with HIV type 1 infection treated with the immune modulant agent tucaresol.

Tucaresol, a Schiff base-forming compound that is shown to enhance cytotoxic T cell responses and the production of type 1 cytokines, represents a potentially useful adjuvant factor for treating HIV-1 infection. We studied the effect of tucaresol on V3 sequences within the HIV-1 env region derived from patients with different virologic and immunologic features who were enrolled in a phase I/II randomized clinical trial. The sequence analysis of the env V3 region of the viruses at baseline has confirmed a genotypic pattern similar to a macrophagotropic virus model; we analyzed the follow-up sequences at week 16 of the protocol and did not observe any difference in the tropism determinants within the third variable fragment of the env region. The administration of tucaresol did not accelerate env V3 evolution thus preventing modifications of HIV-1 tropism over time.

Efficacy and tolerability of multiple drug therapy in HIV-infected children.

OBJECTIVES: To characterize the efficacy and tolerability of multiple drug therapy (MDT) among heavily pre-treated HIV-infected children. METHODS: An observational study of seven children treated with 4-7 antiretroviral agents. MDT regimens were chosen with regard to past antiretroviral exposure and genotypic resistance data. Five children received MDT once, one child twice and one child four times. All patients had AIDS and severe CD4+ depletion and failed >2 PI-based HAART regimens. RESULTS: Virologic response, defined as a > or =log10 decrease in plasma HIV-1 RNA at week 24, was achieved in 7/11 MDT. Successful MDT kept a sustained viral suppression (<50 copies/ml) at longest follow-up (72-96 weeks). Successful MDT obtained a great immune recovery: the median rise in absolute and percentage of CD4+ cells was 261 and 4 at week 24 and it reached 480 and 16 at 72-96 weeks. Adverse events were common but generally manageable. Mild/moderate gastrointestinal complaints and laboratory abnormalities were detected in 5/11 and 8/11 MDT. Grade 2 severity pancreatitis occurred in one case with chronic active hepatitis C. Pancreatitis resolved within 30 days of MDT interruption. CONCLUSIONS: MDT may be a therapeutic option in children who failed to respond to most standard HAART regimens.

Analysis of protease inhibitor combinations in vitro: activity of lopinavir, amprenavir and tipranavir against HIV type 1 wild-type and drug-resistant isolates.

BACKGROUND: Despite the increasing number of antiretroviral compounds, the number of useful drug regimens is limited owing to the high frequency of cross-resistance. PATIENTS AND METHODS: We studied in vitro two-drug combinations using three protease inhibitors (PIs), tipranavir, amprenavir and lopinavir, on isolates (003 and 004) derived from patients with resistance to multiple PIs compared with the drug-susceptible isolate 14aPre in peripheral blood mononuclear cells. Drug interactions were determined by median dose-effect analysis, with the combination index calculated at several inhibitory concentrations (IC). RESULTS: In 14aPre experiments, the combination tipranavir + lopinavir demonstrated synergy at low concentrations (IC(50)), an additive effect at IC(75) and antagonism at IC(90)-IC(95); tipranavir + amprenavir were antagonistic at all concentrations except IC(95), where they were synergic; and the lopinavir + amprenavir combination was always antagonistic. In 003 and 004 infections, tipranavir + lopinavir and tipranavir + amprenavir combinations were antagonistic, and lopinavir + amprenavir were synergic, at all concentrations, with the exception of being additive at IC(95). CONCLUSIONS: Our in vitro experiments did not show any advantage in combining second generation PIs as a therapeutic strategy in naive or multi-treatment failure subjects, with the exception of tipranavir + amprenavir at IC(95) in infections by a wild-type isolate.

Unusual codon 69 insertions: influence on human immunodeficiency virus type 1 reverse transcriptase drug susceptibility.

INTRODUCTION: Multiple amino acid changes in the reverse transcriptase (RT) enzyme of the human immunodeficiency virus 1 (HIV-1) confer simultaneous resistance to most nucleoside RT inhibitors (NRTI). It may take place through different pathways: one of these is the codon 69 insertion, which can involve several 2-amino acid patterns. MATERIALS AND METHODS: We are reporting the case of three patients treated with various antiretroviral compounds. For these subjects we have conducted both a genotypical and a phenotypical analysis in order to understand what kind of influence these insertions may have on HIV-1 RT drug susceptibility. Plasma samples from these patients have been extracted and the RT region has been amplified, cloned and sequenced; meanwhile their PBMCs have been separated, cultivated and then tested for drug susceptibility. RESULTS: Data obtained from the cloning assay showed that the patients had different mutational patterns but constant multiple resistance to NRTI. In particular, they harbored mutations related to Zidovudine (ZDV), 3TC and various NRTIs. Moreover, all three samples had a T69S substitution followed by three different dual amino acid insertions: SG, TG and VG. Several phenotypic experiments revealed that the viruses were resistant to 3TC as well as to ZDV and ABC. Different results were obtained using d4T and ddI. DISCUSSION: In our three patients, all mutation inserts impaired the use of NRTI, particularly ZDV and 3TC. Patient 001 presented a pattern that should not cause a high phenotypic resistance to 3TC per se, and so we can argue that the concomitant presence of the insertion T69S (SG) makes this isolate moderately resistant to this drug. We observed a similar phenomenon in subject 003. d4T was less involved in the resistance generation caused by the RT insertion (in one out of three cases). Moreover, we identified a new 2aa insertion (TG) that has, to the best of our knowledge, never been reported before. A careful survey of novel RT genotypic insertion is thus warranted.