Storage conditions, sample integrity, interferences, and a decision tool for investigating unusual high-sensitivity cardiac troponin results.

The current definition of high-sensitivity cardiac troponin (hs-cTn) assays is laboratory-based and their analytical attributes and characteristics have drawn significant attention in the literature at least partly due to the lower concentration cut-offs and changes in concentrations (i.e., deltas) employed in different algorithms and pathways to manage patient care. We propose that pre-analytical conditions such as sample type, storage conditions, and other interferences may also have a significant impact on hs-cTn concentrations and clinical management. The purpose of this literature review is to provide a summary of important pre-analytical and interference studies affecting hs-cTn concentrations. A breakdown of the literature for the major diagnostic companies providing core laboratory instrumentation (i.e., Abbott, Beckman, Ortho, Roche, and Siemens) is also provided. Finally, three cases are highlighted where knowledge of pre-analytical factors aids the hs-cTn clinically discordant investigations. This review highlights the importance of pre-analytical variables, especially storage condition, sample handling, and blood tubes used (i.e., sample type) when interpreting hs-cTn assays. Additional studies are needed to further elaborate on pre-analytical variables (i.e., centrifugation, sample type, stability) and interferences for all hs-cTn assays in clinical use, as knowledge of these variables may aid in hs-cTn clinically discordant investigations.

Selectivity Determinants of RHO GTPase Binding to IQGAPs.

IQ motif-containing GTPase-activating proteins (IQGAPs) modulate a wide range of cellular processes by acting as scaffolds and driving protein components into distinct signaling networks. Their functional states have been proposed to be controlled by members of the RHO family of GTPases, among other regulators. In this study, we show that IQGAP1 and IQGAP2 can associate with CDC42 and RAC1-like proteins but not with RIF, RHOD, or RHO-like proteins, including RHOA. This seems to be based on the distribution of charged surface residues, which varies significantly among RHO GTPases despite their high sequence homology. Although effector proteins bind first to the highly flexible switch regions of RHO GTPases, additional contacts outside are required for effector activation. Sequence alignment and structural, mutational, and competitive biochemical analyses revealed that RHO GTPases possess paralog-specific residues outside the two highly conserved switch regions that essentially determine the selectivity of RHO GTPase binding to IQGAPs. Amino acid substitution of these specific residues in RHOA to the corresponding residues in RAC1 resulted in RHOA association with IQGAP1. Thus, electrostatics most likely plays a decisive role in these interactions.

Mitochondrial ATP-Dependent Proteases-Biological Function and Potential Anti-Cancer Targets.

Cells must eliminate excess or damaged proteins to maintain protein homeostasis. To ensure protein homeostasis in the cytoplasm, cells rely on the ubiquitin-proteasome system and autophagy. In the mitochondria, protein homeostasis is regulated by mitochondria proteases, including four core ATP-dependent proteases, m-AAA, i-AAA, LonP, and ClpXP, located in the mitochondrial membrane and matrix. This review will discuss the function of mitochondrial proteases, with a focus on ClpXP as a novel therapeutic target for the treatment of malignancy. ClpXP maintains the integrity of the mitochondrial respiratory chain and regulates metabolism by degrading damaged and misfolded mitochondrial proteins. Inhibiting ClpXP genetically or chemically impairs oxidative phosphorylation and is toxic to malignant cells with high ClpXP expression. Likewise, hyperactivating the protease leads to increased degradation of ClpXP substrates and kills cancer cells. Thus, targeting ClpXP through inhibition or hyperactivation may be novel approaches for patients with malignancy.

Nanoluciferase complementation-based bioreporter reveals the importance of N-linked glycosylation of SARS-CoV-2 S for viral entry.

The ongoing COVID-19 pandemic has highlighted the immediate need for the development of antiviral therapeutics targeting different stages of the SARS-CoV-2 life cycle. We developed a bioluminescence-based bioreporter to interrogate the interaction between the SARS-CoV-2 viral spike (S) protein and its host entry receptor, angiotensin-converting enzyme 2 (ACE2). The bioreporter assay is based on a nanoluciferase complementation reporter, composed of two subunits, large BiT and small BiT, fused to the S receptor-binding domain (RBD) of the SARS-CoV-2 S protein and ACE2 ectodomain, respectively. Using this bioreporter, we uncovered critical host and viral determinants of the interaction, including a role for glycosylation of asparagine residues within the RBD in mediating successful viral entry. We also demonstrate the importance of N-linked glycosylation to the RBD's antigenicity and immunogenicity. Our study demonstrates the versatility of our bioreporter in mapping key residues mediating viral entry as well as screening inhibitors of the ACE2-RBD interaction. Our findings point toward targeting RBD glycosylation for therapeutic and vaccine strategies against SARS-CoV-2.

A genome-wide CRISPR/Cas9 screen in acute myeloid leukemia cells identifies regulators of TAK-243 sensitivity.

TAK-243 is a first-in-class inhibitor of ubiquitin-like modifier activating enzyme 1 that catalyzes ubiquitin activation, the first step in the ubiquitylation cascade. Based on its preclinical efficacy and tolerability, TAK-243 has been advanced to phase I clinical trials in advanced malignancies. Nonetheless, the determinants of TAK-243 sensitivity remain largely unknown. Here, we conducted a genome-wide CRISPR/Cas9 knockout screen in acute myeloid leukemia (AML) cells in the presence of TAK-243 to identify genes essential for TAK-243 action. We identified BEN domain-containing protein 3 (BEND3), a transcriptional repressor and a regulator of chromatin organization, as the top gene whose knockout confers resistance to TAK-243 in vitro and in vivo. Knockout of BEND3 dampened TAK-243 effects on ubiquitylation, proteotoxic stress, and DNA damage response. BEND3 knockout upregulated the ATP-binding cassette efflux transporter breast cancer resistance protein (BCRP; ABCG2) and reduced the intracellular levelsof TAK-243. TAK-243 sensitivity correlated with BCRP expression in cancer cell lines of different origins. Moreover, chemical inhibition and genetic knockdown of BCRP sensitized intrinsically resistant high-BCRP cells to TAK-243. Thus, our data demonstrate that BEND3 regulates the expression of BCRP for which TAK-243 is a substrate. Moreover, BCRP expression could serve as a predictor of TAK-243 sensitivity.

Mitochondrial ClpP serine protease-biological function and emerging target for cancer therapy.

Mitochondrial ClpP is a serine protease located in the mitochondrial matrix. This protease participates in mitochondrial protein quality control by degrading misfolded or damaged proteins, thus maintaining normal metabolic function. Mitochondrial ClpP is a stable heptamer ring with peptidase activity that forms a multimeric complex with the ATP-dependent unfoldase ClpX (ClpXP) leading to proteolytic activity. Emerging evidence demonstrates that ClpXP is over-expressed in hematologic malignancies and solid tumors and is necessary for the viability of a subset of tumors. In addition, both inhibition and hyperactivation of ClpXP leads to impaired respiratory chain activity and causes cell death in cancer cells. Therefore, targeting mitochondrial ClpXP could be a novel therapeutic strategy for the treatment of malignancy. Here, we review the structure and function of mitochondrial ClpXP as well as strategies to target this enzyme complex as a novel therapeutic approach for malignancy.

Implications for SARS-CoV-2 Vaccine Design: Fusion of Spike Glycoprotein Transmembrane Domain to Receptor-Binding Domain Induces Trimerization.

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic presents an urgent need for an effective vaccine. Molecular characterization of SARS-CoV-2 is critical to the development of effective vaccine and therapeutic strategies. In the present study, we show that the fusion of the SARS-CoV-2 spike protein receptor-binding domain to its transmembrane domain is sufficient to mediate trimerization. Our findings may have implications for vaccine development and therapeutic drug design strategies targeting spike trimerization. As global efforts for developing SARS-CoV-2 vaccines are rapidly underway, we believe this observation is an important consideration for identifying crucial epitopes of SARS-CoV-2.

Assessment of Tubal Patency: A Prospective Comparison of Diagnostic Hysteroscopy and Laparoscopic Chromopertubation.

STUDY OBJECTIVE: To evaluate whether the presence of a visualizable "flow" effect in the fallopian tube ostia in hysteroscopy was predictive of tubal patency. DESIGN: A prospective cohort study. SETTING: In a prospective study, infertile women who underwent surgery because of infertility between March and November 2018 were included. The main outcome parameter was fallopian tube patency assessed by laparoscopic chromopertubation. The predictive parameter tested was the presence of hysteroscopic tube flow. PATIENTS: Seventy-two infertile women. INTERVENTIONS: Combined hysteroscopy and laparoscopy with chromopertubation. RESULTS: One-hundred forty-four fallopian tubes were evaluated, with 88 (61.1%) patent tubes at laparoscopic chromopertubation. A positive hysteroscopic flow effect was recorded for 94 (65.3%) ostia and was accurate in predicting patency (p < .001), with a sensitivity of 85.3% (95% confidence interval [CI], 76.1-91.9) and a specificity of 66.1% (95% CI, 52.2-78.2). A multivariate binary regression model revealed that the presence of a hydrosalpinx (odds ratio = 8.216; 95% CI, 1.062-63.574; p = .044) and peritubal adhesions (odds ratio = 3.439; 95% CI, 1.142-10.353; p = .028) were associated with a false-normal flow result. A hazy hysteroscopic picture was found in 15 of 21 (71.4%) and 5 of 51 (9.8%) cases with and without bilateral tubal occlusion, respectively (p < .001, sensitivity = 71.4% [95% CI, 47.8-88.7], specificity = 90.2% [95% CI, 78.6-96.7]). CONCLUSIONS: The presence of hysteroscopic tubal flow was a reliable indicator of tubal patency. A hydrosalpinx or peritubal adhesions increase the risk for a false-normal result. A hazy hysteroscopic picture suggests bilateral tubal occlusion. Using the hysteroscopic flow effect, one can provide additional information for the patient.

New model for the interaction of IQGAP1 with CDC42 and RAC1.

The specific and rapid formation of protein complexes, involving IQGAP family proteins, is essential for diverse cellular processes, such as adhesion, polarization, and directional migration. Although CDC42 and RAC1, prominent members of the RHO GTPase family, have been implicated in binding to and activating IQGAP1, the exact nature of this protein-protein recognition process has remained obscure. Here, we propose a mechanistic framework model that is based on a multiple-step binding process, which is a prerequisite for the dynamic functions of IQGAP1 as a scaffolding protein and a critical mechanism in temporal regulation and integration of cellular pathways.

A gain-of-functional screen identifies the Hippo pathway as a central mediator of receptor tyrosine kinases during tumorigenesis.

The Hippo pathway has emerged as a key signaling pathway that regulates various biological functions. Dysregulation of the Hippo pathway has been implicated in a broad range of human cancer types. While a number of stimuli affecting the Hippo pathway have been reported, its upstream kinase and extracellular regulators remain largely unknown. Here we performed the first comprehensive gain-of-functional screen for receptor tyrosine kinases (RTKs) regulating the Hippo pathway using an RTK overexpression library and a Hippo signaling activity biosensor. Surprisingly, we found that the majority of RTKs could regulate the Hippo signaling activity. We further characterized several of these novel relationships [TAM family members (TYRO3, AXL, METRK), RET, and FGFR family members (FGFR1 and FGFR2)] and found that the Hippo effectors YAP/TAZ are central mediators of the tumorigenic phenotypes (e.g., increased cell proliferation, transformation, increased cell motility, and angiogenesis) induced by these RTKs and their extracellular ligands (Gas6, GDNF, and FGF) through either PI3K or MAPK signaling pathway. Significantly, we identify FGFR, RET, and MERTK as the first RTKs that can directly interact with and phosphorylate YAP/TAZ at multiple tyrosine residues independent of upstream Hippo signaling, thereby activating their functions in tumorigenesis. In conclusion, we have identified several novel kinases and extracellular stimuli regulating the Hippo pathway. Our findings also highlight the pivotal role of the Hippo pathway in mediating Gas6/GDNF/FGF-TAM/RET/FGFR-MAPK/PI3K signaling during tumorigenesis and provide a compelling rationale for targeting YAP/TAZ in RTK-driven cancers.

Identification of Celastrol as a Novel YAP-TEAD Inhibitor for Cancer Therapy by High Throughput Screening with Ultrasensitive YAP/TAZ-TEAD Biosensors.

The Hippo pathway has emerged as a key signaling pathway that regulates a broad range of biological functions, and dysregulation of the Hippo pathway is a feature of a variety of cancers. Given this, some have suggested that disrupting the interaction of the Hippo core component YAP and its paralog TAZ with transcriptional factor TEAD may be an effective strategy for cancer therapy. However, there are currently no clinically available drugs targeting the YAP/TAZ-TEAD interaction for cancer treatment. To facilitate screens for small molecule compounds that disrupt the YAP-TEAD interaction, we have developed the first ultra-bright NanoLuc biosensor to quantify YAP/TAZ-TEAD protein-protein interaction (PPI) both in living cells and also in vitro using biosensor fusion proteins purified from bacteria. Using this biosensor, we have performed an in vitro high throughput screen (HTS) of small molecule compounds and have identified and validated the drug Celastrol as a novel inhibitor of YAP/TAZ-TEAD interaction. We have also demonstrated that Celastrol can inhibit cancer cell proliferation, transformation, and cell migration. In this study, we describe a new inhibitor of the YAP/TAZ-TEAD interaction warranting further investigation and offer a novel biosensor tool for the discovery of other new Hippo-targeting drugs in future work.

A kinome-wide screen using a NanoLuc LATS luminescent biosensor identifies ALK as a novel regulator of the Hippo pathway in tumorigenesis and immune evasion.

The Hippo pathway is an emerging signaling pathway that plays important roles in organ size control, tissue homeostasis, tumorigenesis, metastasis, drug resistance, and immune response. Although many regulators of the Hippo pathway have been reported, the extracellular stimuli and kinase regulators of the Hippo pathway remain largely unknown. To identify novel regulars of the Hippo pathway, in this study we created the first ultra-bright NanoLuc biosensor (BS) to monitor the activity of large tumor suppressor (LATS) kinase 1, a central player of the Hippo pathway. We show that this NanoLuc BS achieves significantly advanced sensitivity and stability both in vitro using purified proteins and in vivo in living cells and mice. Using this BS, we perform the first kinome-wide screen and identify many kinases regulating LATS and its effectors yes-associated protein (YAP) and transcriptional co-activator with PDZ- binding motif (TAZ). We also show for the first time that activation of receptor tyrosine kinase anaplastic lymphoma kinase (ALK) by its extracellular ligand family with sequence similarity (FAM)150 activates Hippo effector YAP/TAZ by increasing their nuclear translocation. Significantly, we show that constitutively active ALK induces tumorigenic phenotypes, such as increased cancer cell proliferation/colony formation via YAP/TAZ and elevated immune evasion via YAP/TAZ-programmed death-ligand 1 in breast and lung cancer cells. In summary, we have developed a new LATS BS for cancer biology and therapeutics research and uncovered a novel ALK-LATS-YAP/TAZ signaling axis that may play important roles in cancer and possibly other biologic processes.-Nouri, K., Azad, T., Lightbody, E., Khanal, P., Nicol, C. J., Yang, X. A kinome-wide screen using a NanoLuc LATS luminescent biosensor identifies ALK as a novel regulator of the Hippo pathway in tumorigenesis and immune evasion.

The impact of a standardized micronutrient supplementation on PCOS-typical parameters: a randomized controlled trial.

PURPOSE: To evaluate whether a micronutrient supplementation preparation that includes a high amount of omega-3 unsaturated acids, other anti-oxidants and co-enzyme Q10 would have an impact on specific serum parameters in women with polycystic ovary syndrome (PCOS). METHODS: The study was designed as a monocentral, randomized, controlled, double-blinded trial, from June 2017 to March 2018 (Clinical Trials ID: NCT03306745). Sixty women with PCOS were assigned to either the "multinutrient supplementation group" (one unlabeled soft capsule containing omega-3 fatty acids and one unlabeled tablet containing folic acid, selenium, vitamin E, catechin, glycyrrhizin, and co-enzyme Q10, for 3 months) or the "control group" (two unlabeled soft capsules containing 200 µg folic acid each, for 3 months). The main outcome parameters were anti-Mullerian hormone (AMH), total testosterone, and androstenedione. In addition, the focus was on luteinizing hormone (LH), follicle-stimulating hormone (FSH), the LH:FSH ratio, sexual hormone-binding globulin (SHBG), and estradiol. RESULTS: In the multinutrient supplementation group, the LH:FSH ratio (2.5 ± 1.1 versus 1.9 ± 0.5, p = 0.001), testosterone (0.50 ± 0.19 versus 0.43 ± 0.15, p = 0.001), and AMH (8.2 ± 4.2 versus 7.3 ± 3.6, p < 0.001) declined significantly, whereas the other parameters, namely estradiol, LH, FSH, androstenedione, and SHBG remained stable. CONCLUSION: A micronutrient supplementation that includes omega-3 fatty acids, folic acid, selenium, vitamin E, catechin, glycyrrhizin, and co-enzyme Q10, given for a minimum of 3 months, is beneficial for women with PCOS in terms of PCOS-specific parameters (LH:FSH ratio, serum testosterone and serum AMH).

The impact of repetitive oocyte retrieval on the ovarian reserve: a retrospective cohort study.

PURPOSE: To investigate a possible influence of repetitive micro-traumata on the ovaries in the course of oocyte retrieval during IVF/ICSI treatment on serum anti-Müllerian hormone (AMH) levels. METHODS: The study included retrospectively collected data from women who underwent three or more consecutive IVF/ICSI treatments between 2007 and 2017. The primary endpoint of the study was to evaluate changes in serum AMH levels on cycle days 1-3 during the course of repetitive IVF/ICSI treatments. RESULTS: A total of 125 patients were included in this study. Median AMH levels before the first, second and third IVF/ICSI cycles were 3.8 ng/mL (IQR 1.8-7.1), 3.3 ng/mL (IQR 1.8-6.1) and 3.0 ng/mL (IQR 1.6-5.3), respectively (p = n.s.). In patients who underwent IVF/ICSI due to polycystic ovary syndrome (PCOS), we found a significant decrease in AMH serum levels between the first [AMH 9.7 ng/mL (IQR 7.4-14.4)] and the third [AMH 5.3 ng/mL (IQR 3.3-10.4)] IVF/ICSI cycles (p = 0.026). When performing a generalized linear model, we found PCOS to be an independent predictor for serum AMH decrease during the course of three oocyte retrievals (p < 0.001). CONCLUSIONS: When comparing the indications for IVF/ICSI, we observed a significant decrease in AMH serum levels after repetitive oocyte retrievals only in women with PCOS, while the decrease in AMH was not significant in patients with tubal factor, endometriosis, male factor and unexplained infertility. This finding leads us to hypothesize that repetitive micro-traumata on the ovarian cortex might diminish/normalize functional ovarian reserve in women with PCOS. Further prospective studies are highly warranted to allow firm conclusions.

Does anti-Mullerian hormone predict the outcome of further pregnancies in idiopathic recurrent miscarriage? A retrospective cohort study.

PURPOSE: To evaluate whether anti-Mullerian hormone, basal follicle-stimulating hormone, luteinizing hormone, estradiol, and female age would predict future outcomes in women with idiopathic recurrent miscarriage. METHODS: One hundred and sixteen women with idiopathic recurrent miscarriage were retrospectively included. Luteal support with or without a combined treatment regimen for idiopathic recurrent miscarriage was applied in a tertiary-care center in Vienna. Occurrence and outcome of further pregnancies were analyzed. RESULTS: Within a median follow-up duration of 42.3 months, 94 women (81.0%) achieved one or more pregnancies. Further miscarriages occurred in 47 patients in whom only a higher number of previous miscarriages was predictive (OR 3.568, 95% CI 1.457-8.738; p = 0.005). Fifty-seven women had a live birth > 23 + 0 gestational weeks. In a multivariate analysis, age (OR 0.920, 95% CI 0.859-0.986; p = 0.019) and the number of previous miscarriages (OR 0.403, 95% CI 0.193-0.841; p = 0.016), but not AMH (OR 1.191, 95% CI 0.972-1.461; p = 0.091) were significantly predictive. CONCLUSION: AMH seems of either no or only minor relevance for the prediction of further miscarriages and live birth in women with idiopathic recurrent miscarriage.

Monitoring Hippo Signaling Pathway Activity Using a Luciferase-based Large Tumor Suppressor (LATS) Biosensor.

The Hippo signaling pathway is a conserved regulator of organ size and has important roles in the development and cancer biology. Due to technical challenges, it remains difficult to assess the activity of this signaling pathway and interpret it within a biological context. The existing literature on large tumor suppressor (LATS) relies on methods that are qualitative and cannot easily be scaled-up for screening. Recently, we have developed a bioluminescence-based biosensor to monitor the kinase activity of LATS-a core component of the Hippo kinase cascade. Here, we describe procedures for how this LATS biosensor (LATS-BS) can be used to characterize Hippo pathway regulators. First, we provide a detailed protocol for investigating the effect of an overexpressed protein candidate (e.g., VEGFR2) on LATS activity using the LATS-BS. Then, we show how the LATS-BS can be used for a small-scale kinase inhibitor screen. This protocol can feasibly be scaled-up to perform larger screens, which undoubtedly will identify novel regulators of the Hippo pathway.

Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes.

Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of phenotypes characterized by variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological anomalies, including a phenotype resembling Noonan syndrome, a developmental disorder caused by dysregulated RAS signaling. In silico, in vitro, and in vivo analyses demonstrate that mutations variably perturb CDC42 function by altering the switch between the active and inactive states of the GTPase and/or affecting CDC42 interaction with effectors, and differentially disturb cellular and developmental processes. These findings reveal the remarkably variable impact that dominantly acting CDC42 mutations have on cell function and development, creating challenges in syndrome definition, and exemplify the importance of functional profiling for syndrome recognition and delineation.

Accuracy of Tubal Patency Assessment in Diagnostic Hysteroscopy Compared with Laparoscopy in Infertile Women: A Retrospective Cohort Study.

STUDY OBJECTIVE: To evaluate whether the presence of a visualizable "flow" effect in the fallopian tube ostia in hysteroscopic routine evaluation is predictive of tube patency. DESIGN: A retrospective cohort study (Canadian Task Force Classification II-2). SETTING: Data from all patients who underwent surgery because of infertility at the study center between 2008 and 2016 were analyzed retrospectively. The main outcome parameter was fallopian tube patency as assessed by laparoscopic chromopertubation. The predictive parameters tested were the presence of hysteroscopic tube "flow," general patient characteristics, and intraoperative findings. PATIENTS: Five hundred eleven infertile women who underwent combined hysteroscopy and laparoscopy were included. INTERVENTIONS: All women underwent combined hysteroscopy and laparoscopy. Some had other interventions when necessary, but no additional interventions were taken because of this study. RESULTS: In an analysis of 998 fallopian tubes, the hysteroscopic assessment of fallopian tube "flow" was highly accurate in predicting fallopian tube patency (p < .001), with a sensitivity of 86.4% (95% confidence interval [CI], 83.7-88.8) and a specificity of 77.6% (95% CI, 72.1-82.5). Risk factors for a false-negative hysteroscopy result were the presence of uterine myomas (odds ratio [OR] = 2.11; 95% CI, 1.10-4.05; p = .025), the presence of a hydrosalpinx on the analyzed side (OR = 2.50, 95% CI, 1.17-5.34; p = .019), and the presence of peritubal adhesions surrounding the analyzed tube (OR = 2.87; 95% CI, 1.21-6.76; p = .016). CONCLUSION: A visualizable tube "flow" in hysteroscopy was accurate in the prediction of tubal patency, with a positive predictive value of about 91%. Knowledge about hysteroscopic fallopian tube "flow" can help to plan the future approach in an individual patient.