Rotational and high-resolution infrared spectrum of HC3_3N: global ro-vibrational analysis and improved line catalogue for astrophysical observations

HC$_3$N is an ubiquitous molecule in interstellar environments, from external galaxies, to Galactic interstellar clouds, star forming regions, and planetary atmospheres. Observations of its rotational and vibrational transitions provide important information on the physical and chemical structure of the above environments. We present the most complete global analysis of the spectroscopic data of HC$_3$N. We have recorded the high-resolution infrared spectrum from 450 to 1350 cm$^{-1}$, a region dominated by the intense $\nu_5$ and $\nu_6$ fundamental bands, located at 660 and 500 cm$^{-1}$, respectively, and their associated hot bands. Pure rotational transitions in the ground and vibrationally excited states have been recorded in the millimetre and sub-millimetre regions in order to extend the frequency range so far considered in previous investigations. All the transitions from the literature and from this work involving energy levels lower than 1000 cm$^{-1}$ have been fitted together to an effective Hamiltonian. Because of the presence of various anharmonic resonances, the Hamiltonian includes a number of interaction constants, in addition to the conventional rotational and vibrational l-type resonance terms. The data set contains about 3400 ro-vibrational lines of 13 bands and some 1500 pure rotational lines belonging to 12 vibrational states. More than 120 spectroscopic constants have been determined directly from the fit, without any assumption deduced from theoretical calculations or comparisons with similar molecules. An extensive list of highly accurate rest frequencies has been produced to assist astronomical searches and data interpretation. These improved data, have enabled a refined analysis of the ALMA observations towards Sgr B2(N2).Comment: 35 pages, 14 figures, accepted for pubblication in ApJ Supplemen

Detection of HHV-6 in thyroid specimens from patients with Hashimoto autoimmune thyroid disease

Background. The involvement of herpesvirus infections has recently been suggested as a major environmental factor in the development of Autoimmune thyroid disease (AITD), but no conclusive data are available. Methods. Fine needle aspiration biopsies from 15 patients with AITD, 10 patients with thyroid neoplasia and 10 patients with benign follicular epithelial lesions were analyzed for the presence of HHV-6 by PCR and real-time qPCR. To verify if HHV-6 has a tropism for thyroid cells, we infected thyroid follicular epithelial Nthy-ori3-1 cells and analyzed viral replication by PCR, RT-PCR and IFA. Results. HHV-6 DNA was detected in 15/15 AITD patients, in 1/10 tumours and in none of the benign tissue specimens. Furthermore, in vitro infection experiments showed that Nthy-ori3-1 cells are permissive to HHV-6 replication, and support productive infection for the first 7 days p.i.. Subsequently HHV-6 persists establishing latency. Conclusions. The detection of HHV-6 DNA in thyroid biopsies and HHV-6 in vitro infection of thyroid cells demonstrate that thyroid tissue represents a target for in vivo HHV-6 infection. The observation that HHV-6 DNA is present in all thyroid specimens from patients with AITD, but not in controls, shows an association between HHV-6 and autoimmune thyroiditis, with a potential role of the virus in the development or triggering of the disease. Although there are no details on the effects of HHV-6 infection on thyroid tissue elements, the immune response to the virus might induce a non-specific inflammatory mechanism, promoting activation and expansion of autoreactive T cells

Increase in Peripheral CD3-CD56brightCD16- Natural Killer Cells in Hashimoto's Thyroiditis Associated with HHV-6 Infection

Hashimoto's thyroiditis (HT) is a very common autoimmune disease of the thyroid. In addition to genetic background, several viruses, including herpesviruses, have been suggested to play a role as possible environmental triggers of disease, but conclusive data are still lacking. Previous results showed that HT patients have an increased cellular immune response directed against the HHV-6 U94 protein and increased NK activity directed against HHV-6 infected thyrocytes.In this study, we characterized the antiviral antibody response and the NK cells activity and subtype in HHV-6 infected HT patients. The results showed that HT subjects have increased prevalence and titer of anti-U94 antibodies and a higher amount of CD3-CD56brightCD16-NK cell percentages compared to controls. Furthermore, the cell activation of CD3-CD56bright NK cells in HT patients significantly correlates with TPO and Tg Ab levels.The results suggest that HHV-6 might contribute to HT development, increasing NK cell secretion of inflammatory cytokines that could sustain the persistence of an inflammatory status in HT patients

Presenza di HHV-6 in campioni tiroidei di pazienti con malattie autoimmuni della tiroide

HHV-6 è un β-herpesvirus ubiquitario nella popolazione umana, che a seguito dell’infezione primaria, stabilisce nell’ospite un’infezione latente e si può riattivare in corso di immunosoppressione. La riattivazione virale è stata associata alla comparsa di numerose patologie ed è inoltre stato suggerito un possibile coinvolgimento del virus in alcune malattie di natura autoimmune quali la sindrome di Sjogren, la Sclerosi Multipla, la sindrome di Bechet, l’Artrite reumatoide e quelle a livello tiroideo (AITD, Autoimmune Thyroid Disease). Dati ottenuti nel nostro laboratorio hanno mostrato che campioni bioptici provenienti da pazienti con AITD contengono un elevato carico di HHV-6, al contrario di quanto si osserva nei tessuti tiroidei provenienti da pazienti con altri tipi di lesioni. Questo ha suggerito una possibile associazione tra infezione e/o riattivazione di HHV-6 e sviluppo di AITD. Poiché non esistono dati in letteratura sul tropismo di HHV-6 nei confronti delle cellule tiroidee, ci siamo proposti di valutare se tali cellule possono effettivamente rappresentare un bersaglio per l’infezione da HHV-6. A tale scopo un inoculo virale cell-free di HHV-6, prodotto nel nostro laboratorio, è stato utilizzato per infettare in vitro cellule epiteliali follicolari di origine tiroidea (Nthy-ori 3.1). I risultati hanno mostrato che il virus è in grado di infettare tali cellule, sviluppando un’infezione produttiva, che viene quindi sostituita da uno stato di latenza dopo 7-10 giorni post-infezione. Anche se non conclusivi, i dati raccolti suggeriscono che ci possa essere un’associazione tra infezione da HHV-6 e sviluppo di AIT

HHV-6A in vitro infection of thyrocytes and T cells alters the expression of miRNA associated to autoimmune thyroiditis

Abstract Background Human herpesviruses have been hypothesized as environmental triggers in the development of autoimmune thyroid diseases (AITD), and in particular active human herpesvirus 6A (HHV-6A) infection was detected in thyrocytes of Hashimoto\u2019s thyroiditis (HT) patients, who also show specific anti-viral immune responses. On the other hand, AITD patients display modulation of specific miRNAs in thyroid tissue and blood. We wanted to ascertain whether HHV-6A infection might be correlated to the miRNA dysregulation observed in AITD. Methods Human thyroid and T-cell lines were infected in vitro with HHV-6A,-6B or \u22127, and analysed for miRNAs expression, either by microarray or by specific RT-PCR assays detecting miRNAs associated with AITD in vivo. Results HHV-6A infection, but not -6B or \u22127 infections, induced a decrease in miR-155_2 expression and an increase in miR-1238 expression in thyrocytes, as well as an increase in the expression levels of several autoimmunity-associated miRNAs in T lymphocytes, including miR-16_1, miR34a, miR-130a, miR-143_1, miR-202, miR-301b, miR-302c, miR-449b, miR-451_1, and miR-1238_2. Conclusions HHV-6A infection modulates miRNAs expression in the cell types involved in the development of AITD. Notably, our in vitro findings correlate with what observed in AITD patients, further supporting the association between HHV-6A infection and AITD development. Moreover, these effects are 6A-specific, emphasizing the differences between the two HHV-6 virus species, and suggesting diverse virus mechanisms of action and therapeutic approaches

Virologic and immunologic evidence supporting an association between HHV-6 and Hashimoto’s thyroiditis

Hashimoto’s thyroiditis (HT) is the most common of all thyroid diseases and is characterized by abundant lymphocyte infiltrate and thyroid impairment, caused by various cell- and antibody-mediated immune processes. Viral infections have been suggested as possible environmental triggers, but conclusive data are not available. We analyzed the presence and transcriptional state of human herpesvirus 6 (HHV-6) in thyroid fine needle aspirates (FNA) and peripheral blood mononuclear cells (PBMCs) from 34 HT patients and 28 controls, showing that HHV-6 DNA prevalence (82% vs. 10%, p≤0.001) and viral load were significantly increased in FNA from HT patients, and thyrocytes from HT FNA displayed a 100-fold higher HHV-6 DNA load compared to infiltrating lymphocytes. In addition, while HHV-6 was strictly latent in positive samples from controls, a low grade acute infection was detected in HT samples. HHV-6 variant characterization was carried out in 10 HT FNA samples, determining that all specimens harbored HHV-6 Variant A. The tropism of HHV-6 for thyroid cells was verified by infection of Nthy-ori3-1, a thyroid follicular epithelial cell line, showing that thyrocytes are permissive to HHV-6 replication, which induces de novo expression of HLA class II antigens. Furthermore, HHV-6-infected Nthy-ori3-1 cells become targets for NK-mediated killing, NK cells from HT patients show a significantly more efficient killing of HHV-6 infected thyroid cells than healthy controls, and HT patients have increased T-cell responses to HHV-6 U94 protein, associated to viral latency. These observations suggest a potential role for HHV-6 (possibly variant A) in the development or triggering of HT