SARS-CoV-2 inhibitory activity of a short peptide derived from internal fusion peptide of S2 subunit of spike glycoprotein.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has posed a great concern in human population. To fight coronavirus emergence, we have dissected the conserved amino acid region of the internal fusion peptide in the S2 subunit of Spike glycoprotein of SARS-CoV-2 to design new inhibitory peptides. Among the 11 overlapping peptides (9-23-mer), PN19, a 19-mer peptide, exhibited a powerful inhibitory activity against different SARS-CoV-2 clinical isolate variants in absence of cytotoxicity. The PN19 inhibitory activity was found to be dependent on conservation of the central Phe and C-terminal Tyr residues in the peptide sequence. Circular dichroism spectra of the active peptide exhibited an alpha-helix propensity, confirmed by secondary structure prediction analysis. The PN19 inhibitory activity, exerted in the first step of virus infection, was reduced after peptide adsorption treatment with virus-cell substrate during fusion interaction. Additionally, PN19 inhibitory activity was reduced by adding S2 membrane-proximal region derived peptides. PN19 showed binding ability to the S2 membrane proximal region derived peptides, confirmed by molecular modelling, playing a role in the mechanism of action. Collectively, these results confirm that the internal fusion peptide region is a good candidate on which develop peptidomimetic anti SARS-CoV-2 antivirals.

The Combination of Sonographic Features and the Seven-Gene Panel May be Useful in the Management of Thyroid Nodules With Indeterminate Cytology.

Introduction: The management of patients with indeterminate thyroid nodules, which account for 10-25% of thyroid fine needle aspiration biopsies (FNABs), is still very challenging. Aim: To verify the utility of the seven-gene panel in combination with ultrasound features in the clinical management of indeterminate thyroid nodules. Results: The study group included 188 indeterminate thyroid nodules, divided into TIR3A (56.4%) and TIR3B (43.6%). A significant correlation between US categories and both cytological and molecular results was observed. In detail, TIR3B cytology was more frequent in EU-TIRADS 4 and 5 nodules (54.7 and 50%, respectively) than in EU-TIRADS 2 and 3 nodules (31%, p = 0.04). Similarly, the rate of a nodule with a mutation increased with the increase of US risk class (6.0% in EU-TIRADS 2 and 3, 9.3% in EUTIRADS-4 and 27.8% in EUTIRAD-5, p = 0.01). Among thyroid nodules submitted to surgery, final histology was benign in 61.4% nodules, while malignancy was diagnosed in 38.6% nodules. Using US score as tool for decision-making in TIR3A subgroup, we correctly classified 64.5% of thyroid nodules. The second tool (seven-gene panel test) was used in the subgroup of US high-risk nodules. By multiple tests with a series approach (US in all cases and US plus seven-gene panel in US high risk nodules) 84% of cases were correctly classified. In TIR3B nodules, using only seven-gene panel as tool for decision making, we correctly classified 61.9% of indeterminate nodules. By multiple tests with series approach (seven-gene panel in all cases and seven-gene panel plus US score in non-mutated nodules) only a slight improvement of thyroid nodule classification (66.6%) was observed. Conclusions: US score seems able to correctly discriminate between TIR3A nodules in which a conservative approach may be used, and those in which additional test, such as molecular test, may be indicated. On the contrary, in TIR3B nodules both US risk stratification and seven-gene panel seem to be of little use, because the risk of thyroid cancer remains high regardless of US score and mutational status.

Nodules in autoimmune thyroiditis are associated with increased risk of thyroid cancer in surgical series but not in cytological series: evidence for selection bias.

BACKGROUND: The association of thyroid cancer and autoimmune thyroiditis (AIT) has been widely addressed, with conflicting results in surgical and cytological series, likely affected by selection bias. OBJECTIVE: The objective of the study was to evaluate the association between the cytological features suggestive or indicative of malignancy and AIT in 2504 consecutive patients (2029 females and 475 males, mean age 58.3 ± 14.1 y) undergoing fine-needle aspiration cytology for thyroid nodules. PATIENTS: Based on the clinical diagnosis, patients were divided into four groups: AIT with nodules (N-AIT, 14.9%); nodular Graves disease (N-GD, 2.8%); nodular goiter and negative thyroid antibodies (NGAb-, 68.4%); and nodular goiter with positive thyroid antibodies (NGAb+, 13.9%). RESULTS: The prevalence of patients with cytological features suggestive (Thy4) or indicative of malignancy (Thy5) was 4.5 % in the N-AIT group, not different compared with the other groups (N-GD, 5.6%; NGAb-, 5.0%; NGAb+, 4.3%). No difference was also found in the other categories (Thy2 and Thy3). When the same analysis was performed in the subgroup of patients (14.3%) with a histological confirmation, we found that the prevalence of differentiated thyroid cancer was significantly higher (P = .01) in the N-AIT group (67.8%) compared with the other groups (N-GD, 40.0%; NGAb-, 37.2%; NGAb+, 36.9%). CONCLUSIONS: The results of our cytological series do not support a link between N-AIT and thyroid cancer. The association between cancer and N-AIT found in the histology-based series is likely due to a selection bias represented by the fact that the prevalent indication for surgery in the N-AIT group was suspicious cytology (60.7% of patients) more frequently than in the other groups.

Impact of proto-oncogene mutation detection in cytological specimens from thyroid nodules improves the diagnostic accuracy of cytology.

CONTEXT: Fine-needle aspiration cytology (FNAC) is the gold standard for the differential diagnosis of thyroid nodules but has the limitation of inadequate sampling or indeterminate lesions. OBJECTIVE: We aimed to verify whether search of thyroid cancer-associated protooncogene mutations in cytological samples may improve the diagnostic accuracy of FNAC. STUDY DESIGN: One hundred seventy-four consecutive patients undergoing thyroid surgery were submitted to FNAC (on 235 thyroid nodules) that was used for cytology and molecular analysis of BRAF, RAS, RET, TRK, and PPRgamma mutations. At surgery these nodules were sampled to perform the same molecular testing. RESULTS: Mutations were found in 67 of 235 (28.5%) cytological samples. Of the 67 mutated samples, 23 (34.3%) were mutated by RAS, 33 (49.3%) by BRAF, and 11 (16.4%) by RET/PTC. In 88.2% of the cases, the mutation was confirmed in tissue sample. The presence of mutations at cytology was associated with cancer 91.1% of the times and follicular adenoma 8.9% of the time. BRAF or RET/PTC mutations were always associated with cancer, whereas RAS mutations were mainly associated with cancer (74%) but also follicular adenoma (26%). The diagnostic performance of molecular analysis was superior to that of traditional cytology, with better sensitivity and specificity, and the combination of the two techniques further contributed to improve the total accuracy (93.2%), compared with molecular analysis (90.2%) or traditional cytology (83.0%). CONCLUSIONS: Our findings demonstrate that molecular analysis of cytological specimens is feasible and that its results in combination with cytology improves the diagnostic performance of traditional cytology.