Intense Labeling Research Articles

Expression of Wnt signaling proteins in rare congenital bladder disorders

Introduction and AimsCongenital bladder anomalies are rare and are a leading cause of end stage renal failure in children. The Wnt signaling pathway, important during embryonic development, has been implicated in the pathogenesis of these conditions through regulation of gene expression, including essential transcription factors. We investigated the expression of four Wnt transcriptional targets, namely, Pygopus 1 (Pygo1), FRA1, TCF7L1 and Connexin 43 (Cx43) in three rare congenital bladder disorders: bladder exstrophy (BE), neurogenic bladder (NGB) and posterior urethral valves (PUV). MethodsBladder tissue samples were collected from patients at the Great Ormond Street Hospital for Sick Children, London, UK, with control (normally-functioning bladder, N=9), BE (N=15), NGB (N=6) and PUV (N=5). Histological analysis was performed using the van Gieson stain to differentiate smooth muscle (SM) and connective tissue (CT) compartments. An unbiased, automated, semi-quantitative immunofluorescence analysis was performed to measure the labelling intensity of four Wnt-related proteins in tissue from these four groups. Results and DiscussionThere was a significant (p<0.05) increase in the expression of Pygo1 in the smooth muscle of all anomalies examined and also in the connective tissue in PUV compared to control. Cx43 also showed overexpression in the smooth muscle across all conditions; however, there was a reduced expression in NGB and an increase in PUV in connective tissue. TCF7L1 showed a significant decrease in both tissue compartments for NGB, whereas FRA1 expression remained unchanged across all anomalies. We also measured colocalization of Wnt-related proteins. TCF7L1 exhibited increased colocalization with Pygo1 and FRA1 in exstrophy compared to control. These results suggest a complex dysregulation of the Wnt pathway in congenital bladder disorders. ConclusionWnt signaling-related proteins show dysregulation in congenital bladder disorders compared to control tissue. Understanding these mechanisms should help towards non-invasive early diagnosis, drug target discovery and development of treatment strategies for these conditions.Summary tableSummary of Wnt-related protein expression and colocalization in bladder exstrophy (BE), neurogenic bladder (NGB) and posterior urethral valves (PUV) disorder compared to normally-functioning control bladder. The table shows the levels of expression as significantly up (↑) down (↓) or no change (-) of Pygopus 1 (Pygo1), Connexin 43 (Cx43), FRA1 and TCF7L1 expression in smooth muscle and connective tissue compartments in BE, NGB and PUV relative to control bladder tissue samples. The table also shows colocalization of six protein pairs of Pygo1 and FRA1; Pygo1 and Cx43; Pygo1 and TCF7L1; FRA1 and Cx43; FRA1 and TCF7L1 and Cx43 and TCF7L1 in bladder disorders compared to control.Summary tableProtein Expression (Smooth muscle)Pygo1Cx43FRA1TCF7L1BE↑↑--NGB↑↑-↓PUV↑↑--Protein Expression (Connective tissue)BE----NGB-↓-↓PUV↑↑--ColocalizationPygo1/FRA1Pygo1/Cx43Pygo1/TCF7L1FRA1/Cx43FRA1/TCF7L1Cx43/TCF7L1Exstrophy--↑-↑-NGB------PUV------

RAP1-GTPase immunostaining is altered in human precancerous and cancerous cervical lesions.

Aim: This study investigated RAP1 immunostaining variation in different cell types during CC progression.Methods: Paraffin-embedded cervical tissues from 101 patients were categorized into control, pre-neoplastic and neoplastic groups. RAP1 immunolocalization, HPV detection and genotyping were performed. A semiquantitative immunoreactive score was employed to compare labeling intensity, cellular localization, nuclear labeling, percentage and distribution of reactive cells.Results: 73% (72/99) of cervical specimens were HPV+. RAP1 was localized in the nucleus and cytoplasm of all samples. Cytoplasmic RAP1 immunoscore was higher than nuclear score in all CC groups. RAP1 intensity increased with lesion severity. SCC samples exhibited predominantly intense RAP1 immunostaining.Conclusion: RAP1 is an efficient biomarker for detecting invasive CC lesions but has limited utility in distinguishing SCC grades.

Improved tools for live imaging of F-actin structures in yeast.

For over 20 years, the most effective probe for live imaging of yeast actin cables has been Abp140-GFP. Here, we report that endogenously-tagged Abp140-GFP poorly decorates actin patches and cables in the bud compartment of yeast cells, while robustly decorating these structures in the mother cell. Using mutagenesis, we found that asymmetric decoration by Abp140 requires F-actin binding. By expressing integrated Bni1-Bnr1 and Bnr1-Bni1 chimeras, we demonstrate that asymmetric cable decoration by Abp140 also does not depend on which formin assembles the cables in each compartment. In contrast, the short actin-binding fragment of Abp140 (known as "Lifeact"), fused to 1x or 3xmNeonGreen and expressed from the endogenous ABP140 promoter, uniformly decorates patches and cables in both compartments. Further, this probe dramatically improves live imaging detection of cables (and patches) without altering their in vivo dynamics or cell growth. Improved detection allows us to visualize cables growing inward from the cell cortex and dynamically interacting with the vacuole. This probe also robustly decorates the cytokinetic actomyosin ring. Because Lifeact-3xmNeon expressed at relatively low levels provides intense labeling of cellular F-actin structures, this tool may improve live imaging in other organisms where higher levels of Lifeact expression are detrimental.

Ototoxicity-related changes in GABA immunolabeling within the rat inferior colliculus

Several studies suggest that hearing loss results in changes in the balance between inhibition and excitation in the inferior colliculus (IC). The IC is an integral nucleus within the auditory brainstem. The majority of ascending pathways from the lateral lemniscus (LL), superior olivary complex (SOC), and cochlear nucleus (CN) synapse in the IC before projecting to the thalamus and cortex. Many of these ascending projections provide inhibitory innervation to neurons within the IC. However, the nature and the distribution of this inhibitory input have only been partially elucidated in the rat. The inhibitory neurotransmitter, gamma aminobutyric acid (GABA), from the ventral nucleus of the lateral lemniscus (VNLL), provides the primary inhibitory input to the IC of the rat with GABA from other lemniscal and SOC nuclei providing lesser, but prominent innervation.There is evidence that hearing related conditions can result in dysfunction of IC neurons. These changes may be mediated in part by changes in GABA inputs to IC neurons. We have previously used gene micro-arrays in a study of deafness-related changes in gene expression in the IC and found significant changes in GAD as well as the GABA transporters and GABA receptors (Holt 2005). This is consistent with reports of age and trauma related changes in GABA (Bledsoe et al., 1995; Mossop et al., 2000; Salvi et al., 2000). Ototoxic lesions of the cochlea produced a permanent threshold shift. The number, intensity, and density of GABA positive axon terminals in the IC were compared in normal hearing and deafened rats. While the number of GABA immunolabeled puncta was only minimally different between groups, the intensity of labeling was significantly reduced. The ultrastructural localization and distribution of labeling was also examined. In deafened animals, the number of immuno gold particles was reduced by 78 % in axodendritic and 82 % in axosomatic GABAergic puncta. The affected puncta were primarily associated with small IC neurons. These results suggest that reduced inhibition to IC neurons contribute to the increased neuronal excitability observed in the IC following noise or drug induced hearing loss. Whether these deafness diminished inhibitory inputs originate from intrinsic or extrinsic CNIC sources awaits further study.

In vivo antibody labeling route and fluorophore dictate labeling efficiency, sensitivity, and longevity.

Leukocytes migrate through the blood and extravasate into organs to surveil the host for infection or cancer. Recently, we demonstrated that intravenous (IV) anti-CD45.2 antibody labeling allowed for precise tracking of leukocyte migration. However, the narrow labeling window can make this approach challenging for tracking rare migration events. Here, we show that altering antibody administration route and fluorophore can significantly extend the antibody active labeling time. We found that while both IV and intraperitoneal (IP) anti-CD45.2 antibody labeled circulating leukocytes after injection, they had different kinetic properties that impacted labeling time and intensity. Quantification of circulating antibody revealed that while unbound IV anti-CD45.2 antibody rapidly decreased, unbound IP anti-CD45.2 antibody increased over one hour. Using in vitro and in vivo serial dilution assays, we found that Alexa Fluor 647 (AF647) and Brilliant Blue 700 (BB700) dyes had the greatest labeling sensitivity compared to other fluorophores. However, IP antibody injection with anti-CD45.2 BB700, but not AF647, resulted in continuous blood leukocyte labeling for over 6 hours. Finally, we leveraged IP anti-CD45.2 BB700 antibody to track slower migrating leukocytes into tumors. We found that IP anti-CD45.2 antibody injection allowed for the identification of ~seven times as many tumor-specific CD8+ T cells that had recently migrated from blood into tumors. Our results demonstrate how different injection routes and fluorophores affect anti-CD45.2 antibody leukocyte labeling and highlight the utility of this approach for defining leukocyte migration in the context of homeostasis and cancer.

Dual-Probe Activity-Based Protein Profiling Reveals Site-Specific Differences in Protein Binding of EGFR-Directed Drugs.

Comparative, dose-dependent analysis of interactions between small molecule drugs and their targets, as well as off-target interactions, in complex proteomes is crucial for selecting optimal drug candidates. The affinity of small molecules for targeted proteins is largely dictated by interactions between amino acid side chains and these drugs. Thus, studying drug-protein interactions at an amino acid resolution provides a comprehensive understanding of the drug selectivity and efficacy. In this study, we further refined the site-specific activity-based protein profiling strategy (ABPP), PhosID-ABPP, on a timsTOF HT mass spectrometer. This refinement enables dual dose-dependent competition of inhibitors within a single cellular proteome. Here, a comparative analysis of two activity-based probes (ABPs), developed to selectively target the epidermal growth factor receptor (EGFR), namely, PF-06672131 (PF131) and PF-6422899 (PF899), facilitated the simultaneous identification of ABP-specific binding sites at a proteome-wide scale within a cellular proteome. Dose-dependent probe-binding preferences for proteinaceous cysteines, even at low nanomolar ABP concentrations, could be revealed. Notably, in addition to the intrinsic affinity of the electrophilic probes for specific sites in targeted proteins, the observed labeling intensity is influenced by several other factors. These include the efficiency of cellular uptake, the stability of the probes, and their intracellular distribution. While both ABPs showed comparable labeling efficiency for EGFR, PF131 had a broader off-target reactivity profile. In contrast, PF899 exhibited a higher labeling efficiency for the ERBB2 receptor and bound to catalytic cysteines in several other enzymes, which is likely to disrupt their catalytic activity. Notably, PF131 effectively labeled ADP/ATP translocase proteins at a concentration of just 1 nm, and we found this affected ATP transport. Analysis of the effect of PF131 and its parent inhibitor Afatinib on murine translocase SLC25A4 (ANT1)-mediated ATP transport strongly indicated that PF131 (10 μM) partially blocked ATP transport. Afatinib was less efficient at inhibiting ATP transport by SLC25A4 than PF131, and the reduction of ATP transport by Afatinib was not significant. Follow-up analysis is required to evaluate the affinity of these inhibitors for ADP/ATP translocase SLC25A4 in more detail. Additionally, the analysis of different binding sites within the EGF receptor and the voltage-dependent anion channel 2 revealed secondary binding sites of both probes and provided insights into the binding poses of inhibitors on these proteins. Insights from the PhosID-ABPP analysis of these two ABPs serve as a valuable resource for understanding drug on- and off-target engagement in a dose- and site-specific manner.

Analysis of PRAME immunocytochemistry in 109 acral malignant melanoma in situ

AimsPreferentially expressed antigen in melanoma (PRAME) recently is a reliable immunohistochemistry (IHC) marker for distinguishing melanoma from other lesions. However, there are few articles focused on PRAME use in acral...

The majority of fact-checking labels in the United States are intense and this decreases engagement intention

Abstract Fact-checking labels have been widely accepted as an effective misinformation correction method. However, there is limited theoretical understanding of fact-checking labels’ impact. This study theorizes that language intensity influences fact-checking label processing and tests this idea through a multi-method design. We first rely on a large-scale observational dataset of fact-checking labels from 7 U.S. fact-checking organizations (N = 33,755) to examine the labels’ language intensity and then use a controlled online experiment in the United States (N = 656) to systematically test the causal effects of fact-checking label intensity (low, moderate, or high) and fact-checking source (professional journalists or artificial intelligence) on perceived message credibility of and the intention to engage with fact-checking messages. We found that two-thirds of existing labels were intense. Such high-intensity labels had null effects on messages’ perceived credibility, yet decreased engagement intention, especially when labels were attributed to AI. Using more intense labels may not be an effective fact-checking approach.

Distribution of muscarinic acetylcholine receptors in hypoglossal motoneurons across postnatal maturation

Upper airway patency is decreased during rapid eye movement (REM) sleep due to loss of genioglossus (primary tongue protruder) tongue muscle tone. During REM sleep, hypoglossal motoneurons (XII MNs), which innervate genioglossus, receive less excitatory noradrenergic drive and may be inhibited by activation of muscarinic acetylcholine receptors. Data from intact adult rats during natural sleep implicates an inhibitory effect of muscarinic acetylcholine receptors on XII MNs. However, data using the rhythmic slice preparation from neonatal mice indicate that muscarine has a net excitatory effect on inspiratory burst amplitude at XII MNs. Our project examines the changes to distribution of muscarinic acetylcholine receptors (mAChRs) at XII MNs across postnatal maturation. We hypothesize there is an increase in inhibitory (M2) and decrease in excitatory (M1, M3, M5) mAChRs at XII MNs with postnatal maturation. We performed double-labeled immunofluorescence experiments on perfused transverse brainstem slices (20μm) under identical conditions across six postnatal age groups: P0-P2, P3-P5, P6-P10, P11-P13, P14-P17, and adult against mAChR targets M1, M2, M3, M5. Slices were co-labeled with choline acetyltransferase (ChAT) and 4’,6-diamidino-2-phenylindole (DAPI). Images were collected using a confocal microscope. 10 individual XII MNs were identified in each slice using positive ChAT labeling as well as anatomical location. ImageJ was used to determine the average XII MN mAChR subtype intensity. Preliminary data (n = 3) indicate that M1 receptors showed a transitory increase in labeling intensity in XII MNs followed by a decrease across development (P1=89±11%, P4-5=100%, P9=76±18%, P12-13=67±8%, P17=67±4%, adult=56±7%, p = 0.13). M3 (n = 3) showed a trend for a transient increase in labeling intensity at P17 (P1=78±41%, P4-5=87±3%, P9=61±13%, P12-13=86±34%, P17=100%, adult=80±23, p = 0.60). M5 (n = 3) expression intensity decreased consistently over maturation (P1=100%, P4-5=92±34%, P9=75±23%, P12-13=70±10%, P17=66±14%, adult=39±12%, p = 0.0257). In contrast, M2 (n = 3) receptor expression intensity remained relatively consistent across maturation (P1 = 88±23%, P4-5 = 100%, P9=88±10%, P12-13 = 75±15%, P17 = 86±18%, adult = 75±10%). These data partly support our hypothesis of a decrease in expression intensity of excitatory M1, M3, and M5 receptor subtypes into adulthood. Contrary to our hypothesis, we observed minimal change in the expression intensity of inhibitory M2 receptors across maturation. The decrease in labeling intensity of excitatory muscarinic receptor subtypes may support the observed shift in muscarinic modulation from excitation to inhibition with postnatal maturation. Arizona Alzheimer's Consortium, NIH. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Characterization of HCN channel subtypes at hypoglossal motoneurons throughout postnatal maturation in mice

The inspiratory phase of breathing includes a stiffening of the upper airway to decrease airway resistance and is mediated by excitatory motor output from hypoglossal motoneurons (XII MNs). This excitation decreases from wakefulness to sleep. This decrease in excitation is in large part due to increasing acetylcholine levels, which activate muscarinic acetylcholine receptors (mAChRs) that have a net inhibitory effect in adult preparations. By contrast, activation of mAChRs in neonatal rodent preparations has a net effect of potentiating inspiratory burst amplitude. Therefore, characterizing changes in muscarinic effects at XII MNs across postnatal maturation will help elucidate the mechanism underlying the shift from muscarinic excitation to inhibition. mAChRs modulate several effector ion channels including the hyperpolarization activated cyclic nucleotide gated (HCN) channel. HCN channels give rise to I h, a mixed cation current activated at hyperpolarized membrane potentials. I h additionally shows upregulation at XII MNs with postnatal maturation. Since there are four HCN subtypes (HCN1-4), the reported changes in I h may be caused by changes in HCN channel subtype levels. HCN1 and HCN2 are most prominent in adult XII MNs, whereas the expression of HCN1-4 in neonates is unknown. Thus, the purpose of this research is to characterize changes in HCN gene and channel expression levels at XII MNs across postnatal maturation. We hypothesis that both HCN1 and HCN2 subtypes will increase with postnatal maturation, and that HCN2 has higher levels than HCN1. To test this hypothesis, we used neuroanatomical techniques to evaluate changes in expression patterns of the four HCN proteins at the XII nuclei across postnatal maturation in CD-1 mice. We performed double-labeled immunofluorescence experiments against HCN1 and HCN2 and co-labeled with choline acetyltransferase (ChAT) on 20μm transverse brainstem slices across six postnatal age groups under identical conditions: P0-P1, P4-P6, P9-P10, P12-P14, P17-P19, and adult. Images of the XII nuclei were collected using a confocal microscope. ImageJ was used to determine the average XII MN HCN subtype intensity across postnatal maturation. Preliminary data suggest that HCN1 (n=2) channels undergo a decrease in expression at P17-19 before a final increase in adulthood (P0-1= 97-100%, P4-6= 92-100%, P9-10= 85-95%, P12-14= 77-97%, P17-19= 61-67%, adult= 71-82%). By contrast, preliminary data suggest that HCN2 (n=2) expression intensity remained relatively consistent with a decrease in labeling intensity at P4-6 (P0-1= 97-100%, P4-6=62-84%, P9-10= 45-95%, P12-14= 67-90%, P17-19= 50-93%, adult= 75-100%). These modest changes in labeling intensity of HCN channel subtypes may not contribute to the observed shift of mAChR modulation at XII MNs from excitation to inhibition with postnatal maturation. Biomedical Sciences, College of Graduate Studies; Department of Physiology, College of Graduate Studies, Midwestern University; NIH/NHLBI Funding: R15HL148870. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Podocyte glycocalyx plays an essential role in the function of GFB and the development of albumin leakage

The role of the cell surface layer, glycocalyx is emerging in various areas of cell biology including signaling, metabolism, and immune response. Although a decrease of podocyte glycocalyx depth in glomerular pathologies has been reported before, the specific role of specialized glycocalyx between the podocyte foot processes and the glomerular basement membrane (GBM) in the function and dysfunction of the glomerular filtration barrier (GFB) is elusive. Here we aimed to develop podocyte or endothelial glycocalyx targeting strategies to gain mechanistic understanding of the specific roles of the glycocalyx in the function of GFB and in the development of albumin leakage. Our overall hypothesis is that the specialized podocyte glycocalyx forms an important additional layer of the GFB and changes in the structure and composition of podocyte glycocalyx leads to GFB dysfunction and the development of albumin leakage. New genetic mouse models were generated by the knock-in of pCAG-Lox-STOP-Lox-EGFP-Sdc1 to generate animals with Cre-dependent expression of a syndecan-1 (Sdc1) fusion protein with N-terminal, extracellular GFP. Sdc1-GFPflox animals were crossed with either Podocin-Cre or Cdh5-Cre mice for the specific genetic labeling of the glycocalyx in podocytes or endothelial cells, respectively. Intravital multiphoton microscopy (MPM) was used to measure changes in the depth of glycocalyx and corresponding changes in GFB function in vivo over time. Endoglycosidase enzymes, such as hyaluronidase (50U/animal), heparinase (0.7 U/mouse), and chondroitinase (1 U/mouse) were used to acutely modify the composition of glycocalyx. Alexa-680 conjugated wheat germ agglutinin (WGA) lectin was used to label the glycosaminoglycan (GAG) component of the glycocalyx; Alexa-594 conjugated albumin was used to visualize GFB permeability. Classic phenotyping of Pod and Cdh5 Sdc1-GFP animals showed no significant difference in terms of systolic blood pressure, glomerular filtration rate, body and kidney weight between the Sdc1-GFP and wild type littermates. The co-localization of the genetic GFP and anti-podocin immunofluorescence co-staining confirmed the podocyte-specific expression of Sdc1-GFP. In vivo MPM imaging of Pod-Sdc1-GFP mouse kidneys revealed intense linear labeling of the podocyte cell surface including the apical and basolateral surfaces of the cell body as well as the surfaces of primary, secondary, and foot processes. Interestingly, the thickness and fluorescence intensity of Sdc1-GFP labeled glycocalyx was greater on the basal surface of the podocyte at the GBM as compared to the apical surface implying the role of glycocalyx in the function of GFB. In addition, labeling of the basolateral surface of the podocyte cell body and podocyte foot processes enabled the visualization of sub-podocyte space. Acute injection of endoglycosidase enzymes significantly (3-fold) reduced Sdc1-GFP fluorescence intensity and the thickness of the linear labeling suggesting the acute shedding of podocyte glycocalyx. Importantly, increased albumin permeability of the GFB was observed simultaneously with the shedding of podocyte glycocalyx, indicating the disruption of GFB charge and size-selective functions. In conclusion, the specialized podocyte glycocalyx at the GBM may function as an important new layer of the GFB and may play an important role in the disruption of GFB functions in disease. ASN Carl W. Gottschalk Research Scholar Grant University of Southern California Dean's Pilot Project Award DK123564. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Association of Serum Levels and Immunohistochemical Labelling of Des-Gamma-Carboxy-Prothrombin in Patients Undergoing Liver Transplantation for Hepatocellular Carcinoma.

Hepatocellular cancer (HCC) is one of the main reasons for liver transplantation (LT). Biomarkers, such as alpha-foetoprotein (AFP) and Des-gamma-carboxy-prothrombin (DCP), can be helpful in defining the recurrence risk post LT. This study aims to evaluate the association between the intensity of DCP immunohistochemical labelling and serum DCP levels in patients undergoing LT for HCC. We carried out a prospective monocentric study including patients who all underwent LT for cirrhosis between 2016 and 2018 and all fell under the Milan criteria. The accepted diagnostic criteria for HCC were contrast-enhanced imaging and histology. Thirty-nine patients were followed for a median of 21 months, with HCC lesions categorized into negative, focally positive, and diffusely positive groups based on DCP immunohistochemistry. The serum DCP levels were significantly higher in the positive groups (258 mAU/mL for the focally and 257 mAU/mL for the diffusely positive) than in the negative group (48 mAU/mL) (p = 0.005) at diagnosis and at the time of liver transplantation (220 mAU/mL for the diffuse positive group). Microvascular invasion (58.8% vs. 19.0% for the diffusely positive and negative groups, respectively, p < 0.001) and lesion size (20 mm in the diffusely labelled group versus 12 mm in the other groups, p = 0.002) were significantly correlated with DCP labelling. Late recurrence occurred only in the positive groups; in the negative group, it occurred within the first 3 months after transplantation. DCP labelling in liver lesions correlates with serum levels and a more aggressive tumour profile. Further investigation is needed to determine if highly DCP-labelled tumours allow for the better selection of high-risk patients before LT.

Mucosal affairs: glycosylation and expression changes of gill goblet cells and mucins in a fish-polyopisthocotylidan interaction.

Secreted mucins are highly O-glycosylated glycoproteins produced by goblet cells in mucosal epithelia. They constitute the protective viscous gel layer overlying the epithelia and are involved in pathogen recognition, adhesion and expulsion. The gill polyopisthocotylidan ectoparasite Sparicotyle chrysophrii, feeds on gilthead seabream (Sparus aurata) blood eliciting severe anemia. Control unexposed and recipient (R) gill samples of gilthead seabream experimentally infected with S. chrysophrii were obtained at six consecutive times (0, 11, 20, 32, 41, and 61 days post-exposure (dpe)). In histological samples, goblet cell numbers and their intensity of lectin labelling was registered. Expression of nine mucin genes (muc2, muc2a, muc2b, muc5a/c, muc4, muc13, muc18, muc19, imuc) and three regulatory factors involved in goblet cell differentiation (hes1, elf3, agr2) was studied by qPCR. In addition, differential expression of glycosyltransferases and glycosidases was analyzed in silico from previously obtained RNAseq datasets of S. chrysophrii-infected gilthead seabream gills with two different infection intensities. Increased goblet cell differentiation (up-regulated elf3 and agr2) leading to neutral goblet cell hyperplasia on gill lamellae of R fish gills was found from 32 dpe on, when adult parasite stages were first detected. At this time point, acute increased expression of both secreted (muc2a, muc2b, muc5a/c) and membrane-bound mucins (imuc, muc4, muc18) occurred in R gills. Mucins did not acidify during the course of infection, but their glycosylation pattern varied towards more complex glycoconjugates with sialylated, fucosylated and branched structures, according to lectin labelling and the shift of glycosyltransferase expression patterns. Gilthead seabream gill mucosal response against S. chrysophrii involved neutral mucus hypersecretion, which could contribute to worm expulsion and facilitate gas exchange to counterbalance parasite-induced hypoxia. Stress induced by the sparicotylosis condition seems to lead to changes in glycosylation characteristic of more structurally complex mucins.

Abstract 6442: Evaluation of drug target engagement on pharmacodynamic biomarkers in human plucked scalp hair

Abstract Plucked hair is a valuable surrogate tissue to monitor pharmacodynamic (PD) responses in a clinical trial. Hair collection is a minimally invasive, simple technique amenable to frequent sampling and hence patient compliance. We have developed a method to assess target expression changes following exposure of plucked hairs to chemotherapeutic agents and other potential therapeutics. Successful ex vivo responses provide proof of concept data prior to clinical studies. Since hairs are epithelial appendages, many signaling pathways active in other epithelial tissues, including cancers, are also present in hairs. Highly proliferative scalp hair can be utilized as a surrogate tissue to measure proliferation, phosphorylation and DNA damage responses after treatment. Furthermore, hairs are highly vascularized, suggesting administered Test Articles may be delivered efficiently to the hair in a similar manner to other highly vascularized tissues, including many tumor types. Human plucked scalp hair was placed in maintenance media in the presence of chemotherapeutic agents that have different mechanisms of action (e.g. Gemcitabine, Epirubicin, Erlotinib) for a range of timepoints. Hairs were fixed post-exposure and longitudinal sections were immunohistochemically labelled for markers relating to DNA damage/repair or signaling pathways directly relating to target engagement. Examples include p-Chk1, g-H2AX, p-ERK1/2, and p-AKT. Quantitative image analysis to measure the level of labelling was performed using an Aperio ScanScope®. The relative number of positively labelled cell nuclei or relative labelled tissue area (depending on the labelling pattern of the target), of the hair outer root sheath was analyzed, along with label intensity. In subsequent clinical trials, formaldehyde fixed hairs from patients were returned to the lab, sectioned, labelled and quantified. If antibody labelling is not possible or more detailed information on pathway modulation may be useful, drug treated plucked hairs can be subjected to Next Generation Sequencing (NGS) gene expression analysis. The expected changes in labelling were observed, reflecting known tumor responses. For example, Gemcitabine (linked to DNA polymerase inhibition) increased p-Chk1 labelling after 4 hours and strongly induced p53 by 24 hours. Epirubicin (anthracycline topoisomerase II inhibitor) increased g-H2AX labelling up to 24 hours. Erlotinib (EGFr pathway inhibitor) decreased levels of both p-ERK1/2 and p-AKT after only 10 minutes. We have demonstrated that plucked hair is a valuable PD biomarker tissue for various chemotherapy agents. Proof of concept studies performed ex vivo can inform the design of clinical studies by indicating optimum biomarkers and timepoints. Further, each hair is an independent unit thereby allowing replicate tissues (hairs) to be sampled, improving statistical confidence compared to single readout markers. Citation Format: Greg Tudor, Frida Ponthan, Adam Boanas, Matt Brown, Catherine Booth. Evaluation of drug target engagement on pharmacodynamic biomarkers in human plucked scalp hair [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6442.

Cholesterol depletion induces mesenchymal properties in oral squamous cell carcinoma cell line.

Cholesterol in cell membranes is crucial for cell signaling, adhesion, and migration. Membranes feature cholesterol-rich caveolae with caveolin proteins, playing roles in epithelial-mesenchymal transition and cancer progression. Despite elevated cholesterol levels in tumors, its precise function and the effects of its depletion in oral squamous cell carcinoma remain unclear. The aim of this study was to evaluate the influence of cholesterol depletion in oral squamous cell carcinoma cell line and epithelial-mesenchymal transition process. Cholesterol depletion was induced on SCC-9 cells by methyl-β-cyclodextrin and cell viability, proliferation, apoptosis, and colony formation capacities were evaluated. Gene and protein expressions were evaluated by reverse transcription polymerase chain reaction (RT-qPCR) and Western Blot, respectively, and cell sublocalization was assessed by immunofluorescence. Cholesterol depletion resulted in alteration of oral squamous cell carcinoma cell morphology at different concentrations of methyl-β-cyclodextrin, as well as decreased cell proliferation and viability rates. Analysis of CAV1 transcript expression revealed increased gene expression in the treated SCC-9 during the 24 h period, at different concentrations of methyl-β-cyclodextrin: 5 , 7.5, 10, and 15 mM, in relation to parental SCC-9. CAV1 protein expression was increased, with subsequent dose-dependent decrease. A statistically significant difference was observed in samples treated with 5 mM of methyl-β-cyclodextrin (p = 0.02, Kruskal-Wallis test). The immunofluorescence assay showed lower cytoplasmic and membrane labeling intensity in the treated samples for CAV1. These findings indicate the modulation of cholesterol as a possible mechanism underlying the regulation of these molecules and activation of epithelial-mesenchymal transition in oral squamous cell carcinoma.

Solubility of α-synuclein species in the L62 mouse model of synucleinopathy

The accumulation of α-synuclein (α-Syn) into Lewy bodies is a hallmark of synucleinopathies, a group of neurological disorders that include Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Small oligomers as well as larger fibrils of α-Syn have been suggested to induce cell toxicity leading to a degenerative loss of neurones. A richer understanding of α-Syn aggregation in disease, however, requires the identification of the different α-Syn species and the characterisation of their biochemical properties. We here aimed at a more in-depth characterisation of the α-Syn transgenic mice, Line 62 (L62), and examined the deposition pattern and solubility of human and murine α-Syn in these mice using immunohistochemical and biochemical methods. Application of multiple antibodies confirmed mAb syn204 as the most discriminatory antibody for human α-Syn in L62. Syn204 revealed an intense and widespread immunohistochemical α-Syn labelling in parietal cortex and hippocampus, and to a lower level in basal forebrain and hindbrain regions. The labelled α-Syn represented somatic inclusions as well as processes and synaptic endings. Biochemical analysis revealed a Triton-resistant human α-Syn pool of large oligomers, a second pool of small oligomers that was not resistant to solubilization with urea/Triton. A third SDS-soluble pool of intermediate sized aggregates containing a mixture of both, human and mouse α-Syn was also present. These data suggest that several pools of α-Syn can exist in neurones, most likely in different cellular compartments. Information about these different pools is important for the development of novel disease modifying therapies aimed at α-Syn.

Fluorescence microscopy shadow imaging for neuroscience.

Fluorescence microscopy remains one of the single most widely applied experimental approaches in neuroscience and beyond and is continuously evolving to make it easier and more versatile. The success of the approach is based on synergistic developments in imaging technologies and fluorophore labeling strategies that have allowed it to greatly diversify and be used across preparations for addressing structure as well as function. Yet, while targeted labeling strategies are a key strength of fluorescence microscopy, they reciprocally impose general limitations on the possible types of experiments and analyses. One recent development that overcomes some of these limitations is fluorescence microscopy shadow imaging, where membrane-bound cellular structures remain unlabeled while the surrounding extracellular space is made to fluoresce to provide a negative contrast shadow image. When based on super-resolution STED microscopy, the technique in effect provides a positive image of the extracellular space geometry and entire neuropil in the field of view. Other noteworthy advantages include the near elimination of the adverse effects of photobleaching and toxicity in live imaging, exhaustive and homogeneous labeling across the preparation, and the ability to apply and adjust the label intensity on the fly. Shadow imaging is gaining popularity and has been applied on its own or combined with conventional positive labeling to visualize cells and synaptic proteins in their parenchymal context. Here, we highlight the inherent limitations of fluorescence microscopy and conventional labeling and contrast these against the pros and cons of recent shadow imaging approaches. Our aim is to describe the brief history and current trajectory of the shadow imaging technique in the neuroscience field, and to draw attention to its ease of application and versatility.

Enhancing diagnostic deep learning via self-supervised pretraining on large-scale, unlabeled non-medical images

BackgroundPretraining labeled datasets, like ImageNet, have become a technical standard in advanced medical image analysis. However, the emergence of self-supervised learning (SSL), which leverages unlabeled data to learn robust features, presents an opportunity to bypass the intensive labeling process. In this study, we explored if SSL for pretraining on non-medical images can be applied to chest radiographs and how it compares to supervised pretraining on non-medical images and on medical images.MethodsWe utilized a vision transformer and initialized its weights based on the following: (i) SSL pretraining on non-medical images (DINOv2), (ii) supervised learning (SL) pretraining on non-medical images (ImageNet dataset), and (iii) SL pretraining on chest radiographs from the MIMIC-CXR database, the largest labeled public dataset of chest radiographs to date. We tested our approach on over 800,000 chest radiographs from 6 large global datasets, diagnosing more than 20 different imaging findings. Performance was quantified using the area under the receiver operating characteristic curve and evaluated for statistical significance using bootstrapping.ResultsSSL pretraining on non-medical images not only outperformed ImageNet-based pretraining (p < 0.001 for all datasets) but, in certain cases, also exceeded SL on the MIMIC-CXR dataset. Our findings suggest that selecting the right pretraining strategy, especially with SSL, can be pivotal for improving diagnostic accuracy of artificial intelligence in medical imaging.ConclusionsBy demonstrating the promise of SSL in chest radiograph analysis, we underline a transformative shift towards more efficient and accurate AI models in medical imaging.Relevance statementSelf-supervised learning highlights a paradigm shift towards the enhancement of AI-driven accuracy and efficiency in medical imaging. Given its promise, the broader application of self-supervised learning in medical imaging calls for deeper exploration, particularly in contexts where comprehensive annotated datasets are limited.Graphical

Cyclooxygenase-2 (COX-2) Expression in Equine Melanocytic Tumors.

Equine melanocytic tumors are common and have an unusual benign behavior with low invasiveness and metastatic rates. However, tumoral mass growth is usually a concern that can have life-threatening consequences. COX-2 is related to oncogenesis, promoting neoplastic cell proliferation, invasion, and metastasis. The aim of this study was to evaluate the immunohistochemical expression of COX-2 in equine melanocytic tumors. Through extension and intensity of labeling, 39 melanocytomas and 38 melanomas were evaluated. Of the malignant tumors, 13.2% were negative and 63.2% presented a low COX-2 expression. Only 6 malignant tumors presented >50% of labeled cells, 18 malignant and 8 benign had an expression between 21 and 50%, 8 malignant and 3 benign tumors had an expression between 6 and 20%, 1 malignant tumor had an expression between 1 and 5%, and 5 malignant and 28 benign tumors had no expression. Malignant tumors showed higher COX-2 expression than did benign tumors, with statistically significant differences. The low levels of COX-2 may be one of the molecular reasons for the presence of expansive mass growth instead of the invasive pattern of other species, which is related to high COX-2 levels.

A chromosome arm from Thinopyrum intermedium × Thinopyrum ponticum hybrid confers increased tillering and yield potential in wheat

Tiller number is a key component of wheat plant architecture having a direct impact on grain yield. Because of their viability, biotic resistance, and abiotic stress tolerance, wild relative species are a valuable gene source for increasing wheat genetic diversity, including yield potential. Agropyron glael, a perennial hybrid of Thinopyrum intermedium and Th. ponticum, was created in the 1930s. Recent genome analyses identified five evolutionarily distinct subgenomes (J, Jst, Jvs, Jr, and St), making A. glael an important gene source for transferring useful agronomical traits into wheat. During a bread wheat × A. glael crossing program, a genetically stable translocation line, WT153397, was developed. Sequential in situ hybridizations (McGISH) with J-, St-, and D-genomic DNA probes and pSc119.2, Afa family, pTa71, and (GAA)7 DNA repeats, as well as molecular markers specific for the wheat 6D chromosome, revealed the presence of a 6DS.6Jvs Robertsonian translocation in the genetic line. Field trials in low-input and high-input breeding nurseries over four growing seasons demonstrated the Agropyron chromosome arm’s high compensating ability for the missing 6DL, as spike morphology and fertility of WT153397 did not differ significantly from those of wheat parents, Mv9kr1 and ‘Mv Karizma.’ Moreover, the introgressed 6Jvs chromosome arm significantly increased the number of productive tillers, resulting in a significantly higher grain yield potential compared to the parental wheat cultivars. The translocated chromosome could be highly purified by flow cytometric sorting due to the intense fluorescent labeling of (GAA)7 clusters on the Thinopyrum chromosome arm, providing an opportunity to use chromosome genomics to identify Agropyron gene variant(s) responsible for the tillering capacity. The translocation line WT153397 is an important genetic stock for functional genetic studies of tiller formation and useful breeding material for increasing wheat yield potential. The study also discusses the use of the translocation line in wheat breeding.