Kallikrein family proteases KLK6 and KLK7 are potential early detection and diagnostic biomarkers for serous and papillary serous ovarian cancer subtypes.

BACKGROUND: Early detection of ovarian cancer remains a challenge due to widespread metastases and a lack of biomarkers for early-stage disease. This study was conducted to identify relevant biomarkers for both laparoscopic and serum diagnostics in ovarian cancer. METHODS: Bioinformatics analysis and expression screening in ovarian cancer cell lines were employed. Selected biomarkers were further validated in bio-specimens of diverse cancer types and ovarian cancer subtypes. For non-invasive detection, biomarker proteins were evaluated in serum samples from ovarian cancer patients. RESULTS: Two kallikrein (KLK) serine protease family members (KLK6 and KLK7) were found to be significantly overexpressed relative to normal controls in most of the ovarian cancer cell lines examined. Overexpression of KLK6 and KLK7 mRNA was specific to ovarian cancer, in particular to serous and papillary serous subtypes. In situ hybridization and histopathology further confirmed significantly elevated levels of KLK6 and KLK7 mRNA and proteins in tissue epithelium and a lack of expression in neighboring stroma. Lastly, KLK6 and KLK7 protein levels were significantly elevated in serum samples from serous and papillary serous subtypes in the early stages of ovarian cancer, and therefore could potentially decrease the high false negative rates found in the same patients with the common ovarian cancer biomarkers human epididymis protein 4 (HE4) and cancer antigen 125 (CA-125). CONCLUSION: KLK6 and KLK7 mRNA and protein overexpression is directly associated with early-stage ovarian tumors and can be measured in patient tissue and serum samples. Assays based on KLK6 and KLK7 expression may provide specific and sensitive information for early detection of ovarian cancer

Middle East Respiratory Syndrome Vaccine Candidates: Cautious Optimism

Efforts towards developing a vaccine for Middle East respiratory syndrome coronavirus (MERS-CoV) have yielded promising results. Utilizing a variety of platforms, several vaccine approaches have shown efficacy in animal models and begun to enter clinical trials. In this review, we summarize the current progress towards a MERS-CoV vaccine and highlight potential roadblocks identified from previous attempts to generate coronavirus vaccines

Coronavirus 2′-O-methyltransferase: A promising therapeutic target

Coronaviruses (CoVs) have been the source of multiple epidemics and a global pandemic since the start of century, and there is an urgent need to understand CoV biology and develop better therapeutics. Here, we review the role of NSP16 in CoV replication, specifically its importance to 2′-O-methylation and CoV RNA capping. We describe the attenuation phenotypes of NSP16-mutant CoVs, the roles of MDA5 and IFITs in sensing and antagonizing viral RNA lacking 2′O methylation, and the dependence on 2′-O-methylation in other virus families. We also detail the growing body of research into targeting 2′-O-methylation for therapeutics or as a platform for live attenuated vaccines. Beyond its role in RNA capping, NSP16 may have yet uncharacterized importance to CoV replication, highlighting the need for continued studies into NSP16 functions. Understanding the full contribution of NSP16 to the replicative fitness of CoVs will better inform the development of treatments against future CoV outbreaks

Complex patterns in networks of hyperexcitable neurons

Complex patterns in neuronal networks emerge from the cooperative activity of the participating neurons, synaptic connectivity and network topology. Several neuron types exhibit complex intrinsic dynamics due to the presence of nonlinearities and multiple time scales. In this paper we extend previous work on hyperexcitability of neuronal networks, a hallmark of epileptic brain seizure generation, which results from the net imbalance between excitation and inhibition and the ability of certain neuron types to exhibit abrupt transitions between low and high firing frequency regimes as the levels of recurrent AMPA excitation change. We examine the effect of different topologies and connection delays on the hyperexcitability phenomenon in networks having recurrent synaptic AMPA (fast) excitation (in the absence of synaptic inhibition) and demonstrate the emergence of additional time scales.Fil: Schindewolf, Craig. New Jersey Institute of Technology; Estados UnidosFil: Kim, Dongwook. New Jersey Institute of Technology; Estados UnidosFil: Bel, Andrea Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Matemática; ArgentinaFil: Rotstein, Horacio. New Jersey Institute of Technology; Estados Unido

SARS-CoV-2 Uses Nonstructural Protein 16 To Evade Restriction by IFIT1 and IFIT3

Understanding the molecular basis of innate immune evasion by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important consideration for designing the next wave of therapeutics. Here, we investigate the role of the nonstructural protein 16 (NSP16) of SARS-CoV-2 in infection and pathogenesis. NSP16, a ribonucleoside 2'-O-methyltransferase (MTase), catalyzes the transfer of a methyl group to mRNA as part of the capping process. Based on observations with other CoVs, we hypothesized that NSP16 2'-O-MTase function protects SARS-CoV-2 from cap-sensing host restriction. Therefore, we engineered SARS-CoV-2 with a mutation that disrupts a conserved residue in the active site of NSP16. We subsequently show that this mutant is attenuated both in vitro and in vivo, using a hamster model of SARS-CoV-2 infection. Mechanistically, we confirm that the NSP16 mutant is more sensitive than wild-type SARS-CoV-2 to type I interferon (IFN-I) in vitro. Furthermore, silencing IFIT1 or IFIT3, IFN-stimulated genes that sense a lack of 2'-O-methylation, partially restores fitness to the NSP16 mutant. Finally, we demonstrate that sinefungin, an MTase inhibitor that binds the catalytic site of NSP16, sensitizes wild-type SARS-CoV-2 to IFN-I treatment and attenuates viral replication. Overall, our findings highlight the importance of SARS-CoV-2 NSP16 in evading host innate immunity and suggest a target for future antiviral therapies. IMPORTANCE Similar to other coronaviruses, disruption of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) NSP16 function attenuates viral replication in a type I interferon-dependent manner. In vivo, our results show reduced disease and viral replication at late times in the hamster lung, but an earlier titer deficit for the NSP16 mutant (dNSP16) in the upper airway. In addition, our results confirm a role for IFIT1 but also demonstrate the necessity of IFIT3 in mediating dNSP16 attenuation. Finally, we show that targeting NSP16 activity with a 2'-O-methyltransferase inhibitor in combination with type I interferon offers a novel avenue for antiviral development

Nucleocapsid mutations in SARS-CoV-2 augment replication and pathogenesis.

While SARS-CoV-2 continues to adapt for human infection and transmission, genetic variation outside of the spike gene remains largely unexplored. This study investigates a highly variable region at residues 203-205 in the SARS-CoV-2 nucleocapsid protein. Recreating a mutation found in the alpha and omicron variants in an early pandemic (WA-1) background, we find that the R203K+G204R mutation is sufficient to enhance replication, fitness, and pathogenesis of SARS-CoV-2. The R203K+G204R mutant corresponds with increased viral RNA and protein both in vitro and in vivo. Importantly, the R203K+G204R mutation increases nucleocapsid phosphorylation and confers resistance to inhibition of the GSK-3 kinase, providing a molecular basis for increased virus replication. Notably, analogous alanine substitutions at positions 203+204 also increase SARS-CoV-2 replication and augment phosphorylation, suggesting that infection is enhanced through ablation of the ancestral 'RG' motif. Overall, these results demonstrate that variant mutations outside spike are key components in SARS-CoV-2's continued adaptation to human infection