Distinct subpopulations of ventral pallidal cholinergic projection neurons encode valence of olfactory stimuli

To better understand the function of cholinergic projection neurons in the ventral pallidum (VP), we examined behavioral responses to appetitive (APP) and aversive (AV) odors that elicited approach or avoidance, respectively. Exposure to each odor increased cFos expression and calcium signaling in VP cholinergic neurons. Activity and Cre-dependent viral vectors selectively labeled VP cholinergic neurons that were activated and reactivated in response to either APP or AV odors, but not both, identifying two non-overlapping populations of VP cholinergic neurons differentially activated by the valence of olfactory stimuli. These two subpopulations showed differences in electrophysiological properties, morphology, and projections to the basolateral amygdala. Although VP neurons are engaged in both approach and avoidance behavioral responses, cholinergic signaling is only required for approach behavior. Thus, two distinct subpopulations of VP cholinergic neurons differentially encode valence of olfactory stimuli and play distinct roles in approach and avoidance behaviors.

Effect of Various Toothpaste Tablets on Gloss and Surface Roughness of Resin-based Composite Materials

OBJECTIVES

To evaluate the effect of various toothpaste tablets on gloss and surface roughness of resin-based composite.

METHODS AND MATERIALS

Sixty-four resin-based composite specimens were divided into four groups of 16 specimens each. Gloss and roughness were measured before and after simulated brushing with three types of toothpaste tablets and one conventional toothpaste: CT: Chewtab Toothpaste Tablets; AT: Anticavity Toothpaste Tablets; HC: Charcoal Toothpaste Tablets; CP: Cavity Protection toothpaste. The Kruskal- Wallis procedure was performed to compare the differences by groups. Post-hoc comparisons were conducted with Bonferroni corrections (α=0.05).

RESULTS

There was a significant drop in gloss for all groups. CT and AT maintained the highest gloss with means of 81.6 GU and 74.1 GU, respectively. The lowest gloss of 24.5 GU was observed for HC. There was a significant increase in roughness for all groups except for CT. CT had the lowest roughness with a mean of 0.034 μm, while HC had the highest roughness with a mean of 0.074 μm. There was a significant correlation between post-brushing gloss and post-brushing roughness (p<0.001, r=-0.884).

CONCLUSION

Chewtab Toothpaste Tablets had the least effect on gloss and roughness, while Charcoal Toothpaste Tablets had the most negative effect on the surface properties of resin-based composites.

Topical anaesthesia and decongestion in rhinology

Topical anaesthesia and decongestion of the sinonasal mucosa are used commonly in rhinology practice to facilitate nasal endoscopy, as well as debridement and biopsies. Topical agents used for sinonasal anaesthesia include lignocaine, tetracaine and cocaine. Unlike lignocaine and tetracaine, cocaine also has a decongestant effect. Phenylephrine, oxymetazoline, xylometazoline or adrenaline are usually added to lignocaine and tetracaine to provide decongestion. Several studies have been performed seeking to identify the optimal nasal preparation for nasal endoscopy in the clinic setting. However, there remains no clear consensus in the literature resulting in ongoing wide variation between anaesthetic-decongestant preparations used in clinical practice. Indeed, some authors have argued that no anaesthetic is required at all for flexible nasendoscopy despite the apparent consensus that nasal instrumentation is generally uncomfortable, inferred by the persistence of ongoing research in this area. This review provides a practical summary of local anaesthetic and decongestant pharmacology as it relates to rhinologic practice and summarises the literature to date, with the goal of identifying current gaps in the literature and guiding future research efforts.

Functionally refined encoding of threat memory by distinct populations of basal forebrain cholinergic projection neurons

Neurons of the basal forebrain nucleus basalis and posterior substantia innominata (NBM/SIp) comprise the major source of cholinergic input to the basolateral amygdala (BLA). Using a genetically encoded acetylcholine (ACh) sensor in mice, we demonstrate that BLA-projecting cholinergic neurons can 'learn' the association between a naive tone and a foot shock (training) and release ACh in the BLA in response to the conditioned tone 24 hr later (recall). In the NBM/SIp cholinergic neurons express the immediate early gene, Fos following both training and memory recall. Cholinergic neurons that express Fos following memory recall display increased intrinsic excitability. Chemogenetic silencing of these learning-activated cholinergic neurons prevents expression of the defensive behavior to the tone. In contrast, we show that NBM/SIp cholinergic neurons are not activated by an innately threatening stimulus (predator odor). Instead, VP/SIa cholinergic neurons are activated and contribute to defensive behaviors in response to predator odor, an innately threatening stimulus. Taken together, we find that distinct populations of cholinergic neurons are recruited to signal distinct aversive stimuli, demonstrating functionally refined organization of specific types of memory within the cholinergic basal forebrain of mice.

Functionally refined encoding of threat memory by distinct populations of basal forebrain cholinergic projection neurons

Neurons of the basal forebrain nucleus basalis and posterior substantia innominata (NBM/SIp) comprise the major source of cholinergic input to the basolateral amygdala (BLA). Using a genetically-encoded acetylcholine (ACh) sensor in mice, we demonstrate that BLA-projecting cholinergic neurons can "learn" the association between a naïve tone and a foot shock (training) and release ACh in the BLA in response to the conditioned tone 24h later (recall). In the NBM/SIp cholinergic neurons express the immediate early gene, Fos following both training and memory recall. Cholinergic neurons that express Fos following memory recall display increased intrinsic excitability. Chemogenetic silencing of these learning-activated cholinergic neurons prevents expression of the defensive behavior to the tone. In contrast, we show that NBM/SIp cholinergic neurons are not activated by an innately threatening stimulus (predator odor). Instead, VP/SIa cholinergic neurons are activated and contribute to defensive behaviors in response to predator odor, an innately threatening stimulus. Taken together, we find that distinct populations of cholinergic neurons are recruited to signal distinct aversive stimuli, demonstrating functionally refined organization of specific types of memory within the cholinergic basal forebrain of mice.

Distinct subpopulations of ventral pallidal cholinergic projection neurons encode valence of olfactory stimuli

The ventral pallidum (VP) mediates motivated behaviors largely via the action of VP GABA and glutamatergic neurons. In addition to these neuronal subtypes, there is a population of cholinergic projection neurons in the VP, whose functional significance remains unclear. To understand the functional role of VP cholinergic neurons, we first examined behavioral responses to an appetitive (APP) odor that elicited approach, and an aversive (AV) odor that led to avoidance. To examine how VP cholinergic neurons were engaged in APP vs. AV responses, we used an immediate early gene marker and in-vivo fiber photometry, examining the activation profile of VP cholinergic neurons in response to each odor. Exposure to each odor led to an increase in the number of cFos counts and increased calcium signaling of VP cholinergic neurons. Activity and cre-dependent viral vectors were designed to label engaged VP cholinergic neurons in two distinct contexts: (1) exposure to the APP odor, (2) followed by subsequent exposure to the AV odor, and vice versa. These studies revealed two distinct, non-overlapping subpopulations of VP cholinergic neurons: one activated in response to the APP odor, and a second distinct population activated in response to the AV odor. These two subpopulations of VP cholinergic neurons are spatially intermingled within the VP, but show differences in electrophysiological properties, neuronal morphology, and projections to the basolateral amygdala. Although VP cholinergic neurons are engaged in behavioral responses to each odor, VP cholinergic signaling is only required for approach behavior. Indeed, inhibition of VP cholinergic neurons not only blocks approach to the APP odor, but reverses the behavior, leading to active avoidance. Our results highlight the functional heterogeneity of cholinergic projection neurons within the VP. These two subpopulations of VP cholinergic neurons differentially encode valence of olfactory stimuli and play unique roles in approach and avoidance behaviors.

Multi-ancestry genome-wide meta-analysis of 56,241 individuals identifies LRRC4C, LHX5-AS1 and nominates ancestry-specific loci PTPRK , GRB14 , and KIAA0825 as novel risk loci for Alzheimer's disease: the Alzheimer's Disease Genetics Consortium

Limited ancestral diversity has impaired our ability to detect risk variants more prevalent in non-European ancestry groups in genome-wide association studies (GWAS). We constructed and analyzed a multi-ancestry GWAS dataset in the Alzheimer's Disease (AD) Genetics Consortium (ADGC) to test for novel shared and ancestry-specific AD susceptibility loci and evaluate underlying genetic architecture in 37,382 non-Hispanic White (NHW), 6,728 African American, 8,899 Hispanic (HIS), and 3,232 East Asian individuals, performing within-ancestry fixed-effects meta-analysis followed by a cross-ancestry random-effects meta-analysis. We identified 13 loci with cross-ancestry associations including known loci at/near CR1 , BIN1 , TREM2 , CD2AP , PTK2B , CLU , SHARPIN , MS4A6A , PICALM , ABCA7 , APOE and two novel loci not previously reported at 11p12 ( LRRC4C ) and 12q24.13 ( LHX5-AS1 ). Reflecting the power of diverse ancestry in GWAS, we observed the SHARPIN locus using 7.1% the sample size of the original discovering single-ancestry GWAS (n=788,989). We additionally identified three GWS ancestry-specific loci at/near ( PTPRK ( P =2.4×10 -8 ) and GRB14 ( P =1.7×10 -8 ) in HIS), and KIAA0825 ( P =2.9×10 -8 in NHW). Pathway analysis implicated multiple amyloid regulation pathways (strongest with P adjusted =1.6×10 -4 ) and the classical complement pathway ( P adjusted =1.3×10 -3 ). Genes at/near our novel loci have known roles in neuronal development ( LRRC4C, LHX5-AS1 , and PTPRK ) and insulin receptor activity regulation ( GRB14 ). These findings provide compelling support for using traditionally-underrepresented populations for gene discovery, even with smaller sample sizes.

The KMT2A recombinome of acute leukemias in 2023

Chromosomal rearrangements of the human KMT2A/MLL gene are associated with de novo as well as therapy-induced infant, pediatric, and adult acute leukemias. Here, we present the data obtained from 3401 acute leukemia patients that have been analyzed between 2003 and 2022. Genomic breakpoints within the KMT2A gene and the involved translocation partner genes (TPGs) and KMT2A-partial tandem duplications (PTDs) were determined. Including the published data from the literature, a total of 107 in-frame KMT2A gene fusions have been identified so far. Further 16 rearrangements were out-of-frame fusions, 18 patients had no partner gene fused to 5'-KMT2A, two patients had a 5'-KMT2A deletion, and one ETV6::RUNX1 patient had an KMT2A insertion at the breakpoint. The seven most frequent TPGs and PTDs account for more than 90% of all recombinations of the KMT2A, 37 occur recurrently and 63 were identified so far only once. This study provides a comprehensive analysis of the KMT2A recombinome in acute leukemia patients. Besides the scientific gain of information, genomic breakpoint sequences of these patients were used to monitor minimal residual disease (MRD). Thus, this work may be directly translated from the bench to the bedside of patients and meet the clinical needs to improve patient survival.

Basal forebrain cholinergic signalling: development, connectivity and roles in cognition

Acetylcholine plays an essential role in fundamental aspects of cognition. Studies that have mapped the activity and functional connectivity of cholinergic neurons have shown that the axons of basal forebrain cholinergic neurons innervate the pallium with far more topographical and functional organization than was historically appreciated. Together with the results of studies using new probes that allow release of acetylcholine to be detected with high spatial and temporal resolution, these findings have implicated cholinergic networks in 'binding' diverse behaviours that contribute to cognition. Here, we review recent findings on the developmental origins, connectivity and function of cholinergic neurons, and explore the participation of cholinergic signalling in the encoding of cognition-related behaviours.

A174 A NOVEL MECHANISM OF CROHN’S DISEASE SEVERITY IN WOMEN: EVALUATING THE IMPACT OF AN ESTROGEN-FARNESOID X RECEPTOR INTERACTION ON INTESTINAL BARRIER FUNCTION

Background

Crohn’s disease (CD) is associated with deficits in intestinal barrier function. Activation of bile acid-sensing nuclear receptor Farnesoid X receptor (NR1H4, FXR) is associated with protective effects against reduced intestinal barrier function; namely through promoting tight junction complex genes (TJCGs) and reducing expression of inflammatory cytokines. The FXR -1G>T variant is associated with decreased FXR activation and increased risk of, and early progression to, CD-related surgery in females only. It is hypothesized an estrogen-FXR interaction is mediating this effect.

Purpose

We aimed to assess the combined effect of estrogen and FXR genetic variation on intestinal barrier function using a cell-based model and its impact in a clinical cohort.

Method

Caco-2 cells were characterized for expression of TJCGs (zonula occludens-1, occludin, junctional adhesion molecule A, and claudin-1 and claudin-2), FXR, and nuclear estrogen receptors (ERα, ERβ) by qPCR. The influence of FXR activation on TJCGs was characterized by incubation of Caco-2 cells with chenodeoxycholic acid (CDCA). FXR-knockout stable Caco-2 line was developed using CRISPR-Cas9 methods and verified by qPCR and genotyping. The effect of estradiol on expression of TJCGs in FXR-knockout and wildtype Caco-2 cell monolayers was compared by qPCR. Future experiments include comparison of FXR-knockout and wildtype monolayer permeability with estrogen exposure by transwell permeability assay.

The effect of FXR genotype and exogenous estrogen CD severity (surgery, hospitalization, fistulizing disease) was evaluated in our female cohort by multivariate analysis.

Result(s)

Increased expression of TJCGs was seen in native Caco-2 monolayers incubated with CDCA. FXR-knockout cell line was then successfully created and confirmed. FXR-knockout cells showed decreased expression of TJCGs with the exception of zonula occludens-1. Estradiol exposure resulted in a dose-dependent decline in TJCGs expression in the wildtype Caco-2 cell line, however this effect was lost in the FXR-knockout cell line.

Preliminary analysis of patient cohort data (n=359) showed exogenous estrogen was associated with lower surgery risk (OR = 0.603, 95% CI= 0.373–0.964, p < 0.05; Fischer’s exact test) and trended towards decreasing fistulizing disease risk in a multiple logistic regression model which included FXR genotype. The association of FXR genotype with increased surgery risk was also confirmed in this logistic regression model.

Conclusion(s)

Herein, we show that FXR activity affects expression of TJCGs, and this effect is attenuated by estrogen interactions. Our patient cohort preliminary analysis confirmed an increased CD severity risk associated with FXR genotype and demonstrated a trend of decreasing CD severity with exogenous estrogen exposure. Further studies will assess the mechanisms by which FXR and estrogen interact to influence intestinal permeability.

Please acknowledge all funding agencies by checking the applicable boxes below

Other

Please indicate your source of funding;

Department of Medicine, Western University

Disclosure of Interest

D. Taylor: None Declared, L. Donovan: None Declared, J. Choi: None Declared, R. Kim: None Declared, U. Schwarz: None Declared, A. Wilson Consultant of: Consulting fees from Fresenius Kabi, Speakers bureau of: Speaking fees from Takeda and Pfizer

Lewy Body Pathology and Alzheimer Disease in Down Syndrome

Introduction/Objective

Aging adults with Down syndrome (DS) develop Alzheimer disease neuropathology (AD) by the age of 40 years, primarily due to the overexpression of the amyloid precursor protein on chromosome 21. Lewy bodies (LBs), containing alpha-synuclein protein, are observed in 7-60% of AD patients in the amygdala and in cortex. Prior DS studies (n=20-56 cases) find the frequency of LB pathology to range between 8-50% of cases being affected. We hypothesized that LB pathology would also be present in DS brain with similar locations and prevalence to AD. Thus, we evaluated the frequency of LB in our UCI cohort of DS cases that we have collected over the past 25 years.

Methods/Case Report

Neuropathology reports from 55 cases with DS from the UCI-ADRC were included in this study. Cases were stained for beta-amyloid, phosphor-tau, alpha-synuclein and TDP-43 as per NACC protocols (one case each v7,8,9 and three v11).

Results (if a Case Study enter NA)

We identified 6 cases (10.9%), all male, with a mean age of 57 years (SD=3) that showed LB and/or Lewy neurites. LB pathology was classified as amygdala predominant in 3 cases, brainstem predominant in one, intermediate/transitional in one, and diffuse/neocortical in one. Five cases were BRAAK stage 6 and one was stage 5. Five cases had CERAD neuritic plaque score C and one case had a B score. Two of 3 cases were Thal phase 5, and one was phase 4. The case with diffuse/neocortical LB pathology demonstrated hippocampal sclerosis.

Conclusion

The observation that all our LB positive cases were male may reflect a sample bias. In our study, Lewy pathology was most common in amygdala but other sites of involvement are seen similar to a prior DS study and AD studies. Prior DS studies (n=20-56 cases) find the frequency of LB pathology to range between 8-50% of cases being affected. The prevalence of LB in our DS cohort (10.9%) is in the low end of the range seen in other DS and AD studies.

An Evaluation of Peer-Rated Surgical Skill and its Relationship With Detrusor Muscle Sampling in Transurethral Resection of Bladder Tumor

OBJECTIVE

To assess the reliability of peer-review of TURBT videos as a means to evaluate surgeon skill and its relationship to detrusor sampling.

METHODS

Urologists from an academic health system submitted TURBT videos in 2019. Ten blinded peers evaluated each surgeon's performance using a 10-item scoring instrument to quantify surgeon skill. Normalized composite skill scores for each surgeon were calculated using peer ratings. For surgeons submitting videos, we retrospectively reviewed all TURBT pathology results (2018-2019) to assess surgeon-specific detrusor sampling. A hierarchical logistic regression model was fit to evaluate the association between skill and detrusor sampling, adjusting for patient and surgeon factors.

RESULTS

Surgeon skill scores and detrusor sampling rates were determined for 13 surgeons performing 245 TURBTs. Skill scores varied from -6.0 to 5.1 [mean: 0; standard deviation (SD): 2.40]. Muscle was sampled in 72% of cases, varying considerably across surgeons (mean: 64.5%; SD: 30.7%). Among 8 surgeons performing >5 TURBTs during the study period, adjusted detrusor sampling rate was associated with sending separate deep specimens (odds ratio [OR]: 1.97; 95% confidence interval [CI]: 1.02-3.81, P = .045) but not skill (OR: 0.81; 95% CI: 0.57-1.17, P = .191).

CONCLUSION

Surgeon skill was not associated with detrusor sampling, suggesting there may be other drivers of variability of detrusor sampling in TURBT.

P-739 Social and treatment characteristics of women with Uterine Fibroid (UF) with/without Heavy Menstrual Bleeding (HMB), in a commercially insured US population

Study question

Are there differences in patient’s social demographic, clinical and treatment characteristics among patients diagnosed with HMB and/or UF?

Summary answer

Baseline characteristics were similar across all UF-status defined-groups. Differences were observed in education, net-worth and 12-monthfollow-up characteristics. Nearly 60% were prescribed pain meds pre-diagnosis.

What is known already

Uterine leiomyomas (or fibroids) are benign neoplasm that affect women of reproductive age1. In the US, treatment for UF is individualized, dependent on size and location of the fibroids, patient profile, symptom severity and type of diagnosis. Patients may be diagnosed with HMB before UF (HMB-UF), diagnosed with UF first and then HMB (UF-HMB), diagnosed with only HMB (HMB-Only) or UF only (UF-Only). Previous studies indicated that the majority (70%) of women received no prescription medications regardless of surgery status and 40% had pain at time of diagnosis.2,3

Study design, size, duration

Our retrospective real-world observational study included 295,400 women across four cohorts between 10/1/2012 -12/31/2020. The majority (96,961; 44%) had HMB-Only, 46,763 (21%) UF-Only, 35,421 (16%) HMB-UF, and 40,806 (19%) UF-HMB. Patients required 12 months continuous enrollment before index date (earlier of HMB or UF diagnosis date based on cohorts) and 12-months of follow-up unless hysterectomy was observed before 12 months. Surgical and pharmacologic agents explored were based on ACOG guidelines for UF.

Participants/materials, setting, methods

Optum® Socio-Economic Status claims database was used to identify newly diagnosed women 18-55 years old with UF and/or HMB claims, without history of conservative/radical surgery or non-dermatological cancers.

Descriptive analyses were performed for patients’ social demographics and treatment characteristics during pre- and post-index period.

Main results and the role of chance

Across all cohorts,

During the 12-month follow-up, nearly 80% of patients used at least 1 prescribed pain medication compared to nearly 60% at baseline. The increase in pain medication use was mainly driven by increase in NSAIDs, opioids, analgesics, and anti-migraine in all cohorts except HMB-O (Opioids: baseline 24-30% to follow up 41-55%; NSAIDs: 20-21% to 44-53%; analgesics: 6-8% to 19%-33%; anti-migraine: 8-11% to 16-29%).

Limitations, reasons for caution

True incidence of index claims are difficult to estimate. Over-the-counters medications or claims made outside the study period are not captured. Pain medication may be unrelated to UF-associated pain.

Findings only reflect the commercially insured population and may not be generalizable. Claims data provide limited clinical profile and prescribing rationales.

Wider implications of the findings

The majority of the patients in these cohorts experienced pain and were prescribed opioids. Determining the link between the use of pain medication and symptoms of UF and HMB is important, as pain medications do not address HMB.

Trial registration number

Not applicable

P-315 The importance of treatment features beyond pain reduction associated with gonadotropin-releasing hormone analogues from the patient perspective

Study question

Beyond reducing pain, how do women with moderate-severe-endometriosis pain prioritize treatment features and outcomes associated with gonadotropin-releasing hormone (GnRH) analogues?

Summary answer

Moderate-severe-endometriosis patients prioritized safe long-term treatment, feeling treatment-effects within a few cycles, being able to maintain employment, reducing fatigue, depression, and headaches, and improving libido.

What is known already

The importance of pain management in endometriosis treatment is well-established. Poor health-related quality of life has been attributed to endometriosis pain, with greater impact as the number of endometriosis symptoms and symptom severity increase. Endometriosis treatment options include analgesics for acute pain episodes and surgery in more severe cases, as well as hormone therapies, including GnRH analogues. The potential risks, benefits, and outcomes associated with currently available GnRH analogues for endometriosis treatment can vary. Data are lacking on the patient perspective with respect to potential treatment features and outcomes beyond just pain reduction.

Study design, size, duration

Treatment-naïve patients with moderate-severe-endometriosis pain (rating scale ≥4 for menstrual pain) in the United States completed a cross-sectional online survey. Best-worst scaling (BWS) was used to assess preferences for key non-pain treatment attributes that were identified based on the literature. Cognitive pre-test interviews were conducted to confirm content validity of the questionnaire. Data collection for this ongoing survey was initiated in December 2021.

Participants/materials, setting, methods

Patients (English-speaking, premenopausal, 18-50 years-old) were recruited via healthcare research panel. Eligible patients self-reported laparoscopy-confirmed-endometriosis, no endometriosis/other gynecological surgery in past 3 months, no osteoporosis/bone disease/uterine fibroids history, and healthcare coverage for previous 3 years. Treatment features in the BWS exercise included dosage flexibility, short treatment onset, reversibility of side effects, reducing fatigue, depression, headache, impact on libido, impact on sleep, ability to maintain employment, duration of treatment, and additional need for contraceptive use.

Main results and the role of chance

Overall, 115 patients (31.1±7.5 years-old) were included in the analyses. On a 0 (no pain) to 10 (pain as bad as you can imagine) scale, the mean worst menstrual and non-menstrual pelvic pain (during past month) were 7.7±1.6 and 5.4±2.7, respectively. The most common endometriosis treatments ever used included over-the-counter pain medications (90.4%) and prescription contraceptives (74.8%).

Of 11 BWS features tested, patients prioritized:

“You can safely take the treatment for a long period of time” (relative importance=11.4%) “Your ability to get or maintain a job” (11.1%) “When starting a treatment, you will begin to feel the treatment’s effects within the first few menstrual cycles” (10.9%) “You will be less depressed” (10.8%) “Your interest in sex will not be affected” (10.7%) “Any side-effects you may experience are resolved quickly after treatment stops” (10.1%) “You will be less fatigued or tired” (9.5%) “You will have fewer headaches or migraines” (8.6%)

Least important to patients were:

“Your sleep will not be affected” (6.8%) “Your doctor offers different options for the dose strength and how often you take it, as appropriate to your needs” (5.9%) “You are not required to take additional contraceptives along with the treatment” (4.0%)

Limitations, reasons for caution

The preferences of patients who participated may differ from those who did not participate, thereby reducing the ability to generalize results. All data were self-reported; diagnosis and treatment could not be independently confirmed. The BWS exercise cannot include all possible attributes and outcomes relevant to patients.

Wider implications of the findings

Beyond pain reduction, patients most highly valued having safe long-term treatment, feeling treatment effects within a few cycles, rapid resolution of side effects, being able to work, maintaining libido, and reducing fatigue, depression, and headaches. These factors can help physicians to better align endometriosis treatment decision-making with patient preferences.

Trial registration number

Not applicable

Abstract 3938: Discovery of a novel small molecule inhibitor of the YAP1/TAZ-TEAD transcriptional complex

Hippo pathway alterations in human cancers often result in dephosphorylation of yes-associated protein (YAP1) and its paralog TAZ (WWTR1), allowing the formation of an active complex with transcriptional enhanced associate domain transcription factors (TEADs). This complex formation results in the activation of pro-survival and pro-proliferative transcriptional programs in cancer cells. Many tumor types harbor alterations in the Hippo pathway, including mesothelioma, where a high percentage of tumors are driven by YAP1/TEAD activity. Although traditionally difficult to drug with small molecules, identification of autopalmitoylation sites in the hydrophobic palmitate pocket of TEADs necessary for YAP1 interaction has enabled modern drug discovery platforms to generate compounds that allosterically inhibit YAP1/TAZ-TEAD complex formation and transcriptional activity. We report the discovery and characterization of the novel YAP1/TAZ-TEAD inhibitor MRK-A from an aryl ether chemical series demonstrating potent and specific inhibition of YAP1/TAZ-TEAD activity. In biochemical thermal shift assays, MRK-A caused a concentration-dependent melting temperature shift of 8-12.5 and 0.6-1.5 degrees for TEAD1 and TEAD2, respectively, indicating direct binding to TEAD protein. In cellular assays, MRK-A demonstrated inhibition of a TEAD-based reporter assay, with little to no activity in multiple orthogonal off-target reporter assays such as WNT, NF-KB, TGFB and PPARG (8.4 nM vs. &gt;10000 nM), which is consistent with the exquisite selectivity profile of this molecule (&gt;1000x selectivity against 350+ measured kinases and other common off-targets). In the NF2-deficient mesothelioma cell line H226, MRK-A suppressed the transcription of endogenous YAP/TAZ-TEAD target genes CYR61, ERBB3, ANKRD1 and CTGF (50-75% inhibition at 100 nM), but not LATS1, a non-TEAD regulated Hippo pathway gene. In co-immunoprecipitation assays, MRK-A disrupted the interaction of YAP1 and TEAD in H226 cells at concentrations consistent with inhibition of target genes. In addition, MRK-A potently blocked the clonogenic growth and viability of H226 cells in a dose-dependent manner (maximal response at 1 µM compound &gt;90% growth inhibition), while sparing the Hippo wild-type mesothelioma cell line H28. Furthermore, structurally similar control compounds, MRK-B and MRK-C, without the ability to block TEAD-mediated transcription (TEAD reporter MCF7 assay IC50 &gt; 10000 nM), did not impact the clonogenic growth of H226 cells. In vivo, MRK-A did not show acute tolerability signals in mice and demonstrated pharmacokinetics suitable for daily oral dosing in efficacy studies. In summary, we report the structure and characterization of MRK-A demonstrating potent and specific inhibition of YAP1/TAZ-TEAD mediated transcriptional responses, with potential implications for treating malignancies driven by altered Hippo signaling.

Citation Format: Casey J. Moure, Christopher Sondey, Mangeng Cheng, My Mansueto, Rafael Fernandez, Sebastian E. Schneider, Julia V. Ramirez, Brian Long, Erin DiMauro, Brandon Vara, Charles Yeung, Abe Achab, Jongwon Lim, Ronald Kim, Cayetana Zarate, Jonathan Bennett, Rachel Palte, Robert Foti, Vladimir Simov, Evan Barry. Discovery of a novel small molecule inhibitor of the YAP1/TAZ-TEAD transcriptional complex [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3938.

Phase II study of ceralasertib (AZD6738) in combination with durvalumab in patients with advanced/metastatic melanoma who have failed prior anti-PD-1 therapy

BACKGROUND

Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR.

PATIENTS AND METHODS

This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy.

RESULTS

Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment.

CONCLUSION

We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.

P–153 Comparison outcome of vitrified human embryos stored in vapor phase liquid nitrogen (LN2) and direct LN2

Study question

Is vapor cryopreserved LN2 storage beneficial for clinical outcomes of vitrified human embryos that are frozen compared to vitrified human embryos having direct contact with LN2.

Summary answer

There are no significant differences compared to clinical outcomes of human embryos stored in LN2 vapor and direct store in LN2.

What is known already

There has been concerned about potential cross-contamination and biohazard issues of embryos for long term storage using direct LN2. This study aimed to compare clinical outcomes of human embryos transfer between vapor phase and liquid LN2.

Study design, size, duration

The embryo has undergone vitrification for long term storage with vapor or direct contact in LN2. After the thawing of the embryo, we checked on the survival rates. We transferred only one or two embryos per patient and kept analyzing the implantation and pregnancy rates

Participants/materials, setting, methods

This retrospective study was carried out from January 2018 to December 2019 with 3272cycles 4713embryos; vitrified for long term storage in vapor phase or direct contact with LN2. We compared the clinical outcomes of frozen embryo transfer cycles using vitrified for long term storage in vapor phase and direct contact with LN2. Clinical outcomes monitored were embryo survival, subsequent implantation and pregnancy after single or double embryo transfer

Main results and the role of chance

A total of 4713 fertilized human embryos are vitrified and then stored in LN2 vapor (n = 2520 cycles) or direct contact LN2 (n = 752 cycles). The study showed that the blastocyst stored in vapor able to retain full development. Survival was 97.8% (vapor) and 97.6% (direct contact LN2), and the vapor storage of human embryos had no significant difference in survival rates after a long term storage. For single blastocyst transfer, pregnancy and implantation rates were 51.5%, 52.4% in vapor, 54.6%, 54.9% in direct LN2; respectively (p=NS). In double blastocyst transfer, the pregnancy and implantation rates were 61.8%, 42.0% in vapor and 64.7%, 44.5% in direct LN2; respectively (p=NS). There were also no significant differences between two groups.

Limitations, reasons for caution

The study showed that the blastocyst stored in vapor can retain full development. A vapor storage system thus is safe and effective for long term vapor storage of vitrified human embryos.Within the limits of this study, there was no detection of an adverse effect of vapor storage.

Wider implications of the findings: Vapor storage systems thus represent a useful alternative for safe and effective long-term storage of vitrified human embryos that can avoid cross contamination chances from having direct contact with LN2.

Trial registration number

Not applicable

A12 PRE-TREATMENT HLADQA1-HLADRB1 TESTING FOR THE PREVENTION OF AZATHIOPRINE-INDUCED PANCREATITIS IN INFLAMMATORY BOWEL DISEASE: A PROSPECTIVE COHORT STUDY

Background

Azathioprine (AZA) therapy has a long history of use in IBD. The need to promote its safe use in this population is ensured by governmental health policy requiring IBD patients to fail low cost drugs, such as AZA, prior to approving funding for more potent biologic therapies. AZA-induced pancreatitis is an idiosyncratic and unpredictable response, occurring in up to 7% of AZA-exposed patients that can lead to patient morbidity, hospitalization, delay in effective IBD management, as well as result in substantial additional health-related costs. There are no tools in clinical practice to identify individuals at risk of AZA-induced pancreatitis. Genetic variation in the HLADQA1-HLADRB1*07:01 haplotype is strongly associated with azathioprine (AZA)-induced pancreatitis in inflammatory bowel disease (IBD).

Aims

To evaluate whether HLA DQA1-HLADRB1*07:01A&gt;C pre-treatment genotype testing in an adult IBD population prior to AZA therapy to guide AZA selection would result in a lower incidence of AZA-induced pancreatitis.

Methods

Participants with IBD (n=599) were screened for HLADQA1-HLADRB1*07:01A&gt;C and participants with a variant genotype were excluded from azathioprine treatment (n=271). Wildtype participants (n=328) were started on azathioprine and followed for 3 months. The incidence of pancreatitis was compared to unscreened historical controls (n=373).

Results

The minor allele frequency of HLADQA1-HLADRB1*07:01 was 30.4% and 30.0% in the screened and unscreened populations respectively. Up to 45.2% of participants were excluded from AZA therapy based on genotype in the HLADQA1-HLADRB1*07:01A&gt;C screened cohort. HLADQA1-HLADRB1*07:01A&gt;C screening resulted in an 11-fold reduction in the odds of azathioprine-induced pancreatitis (0.30% versus 3.4%, OR=0.085, 95%CI=0.011–0.651, p=0.002).

Conclusions

HLA DQA1-HLADRB1*07:01A&gt;C screening substantially reduced the risk of pancreatitis during AZA treatment in patients with IBD. However, using this strategy as a tool for guiding the use of AZA therapy in IBD may eliminate a large proportion of patients from being eligible for treatment with AZA. In regions, where there is access to other IBD therapies, and given the short and long term toxicities associated with AZA, HLA DQA1-HLADRB1*07:01A&gt;C screening may be a clinically-relevant strategy for enhancing the safe use of AZA in IBD. Additionally, cost-effectiveness analyses are needed to further solidify the utility of HLA DQA1-HLADRB1*07:01A&gt;C-screening in IBD populations.

Funding Agencies

Academic Medical Organization of Southwestern Ontario Innovation Fund

Right ventricular longitudinal strain measured using feature-tracking cardiac magnetic resonance is an independent predictor of all cause mortality in patients with severe tricuspid regurgitation

Introduction

Tricuspid regurgitation imposes a volume overload on the right ventricle (RV) that can lead to progressive RV dilation and dysfunction. Overt RV dysfunction is associated with poor prognosis and increased operative risk. Abnormalities of myocardial strain may provide the earliest evidence of ventricular dysfunction. CMR feature-tracking techniques now allow assessment of strain from routine cine-images, without specialized pulse sequences. Whether abnormalities of RV strain measured using CMR feature-tracking have prognostic value in patients with tricuspid regurgitation is unknown

Purpose

To evaluate the prognostic value of CMR feature-tracking derived RV free wall longitudinal strain (RVFWLS) in a large multicenter population of patients with severe tricuspid regurgitation.

Methods

Consecutive patients with severe tricuspid regurgitation undergoing CMR at four US medical centers were included in this study. Feature-tracking RVFWLS was calculated from 4 chamber cine-views (Figure-left panel). The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between RVFWLS and death. The incremental prognostic value of RVFWLS was assessed in nested models.

Results

Of the 406 patients in this study,115 died during a median follow-up of 8.8 years. By Kaplan-Meier-analysis, patients with RVFWLS ≥median (−16%) had significantly reduced event free survival compared to those with RVFWLS &lt; median (log-rank p&lt;0.001) (Figure-right panel). By Cox multivariable regression modeling, each 1% worsening in RVFWLS was associated with a 13% increased risk-of-death after adjustement for clinical and imaging risk factors (HR=1.13 per %; p&lt;0.001). Addition of RVFWLS in this model resulted in significant-improvement in the global-chi-square (26 to 65; p&lt;0.0001).

Conclusions

CMR feature-tracking derived RVFWLS is an independent predictor of mortality in patients with severe tricuspid regurgitation, incremental to common clinical and imaging risk factors.

Funding Acknowledgement

Type of funding source: None

High-Resolution Three-Dimensional Imaging of Individual Astrocytes Using Confocal Microscopy

Astrocytes play numerous vital roles in the central nervous system. Accordingly, it is of merit to identify structural and functional properties of astrocytes in both health and disease. The majority of studies examining the morphology of astrocytes have employed immunoassays for markers such as glial fibrillary acidic protein, which are insufficient to encapsulate the considerable structural complexity of these cells. Herein, we describe a method utilizing a commercially available and validated, genetically encoded membrane-associated fluorescent marker of astrocytes, AAV5-GfaABC1D-Lck-GFP. This tool and approach allow for visualization of a single isolated astrocyte in its entirety, including fine peripheral processes. Astrocytes are imaged using confocal microscopy and reconstructed in three dimensions to obtain detailed morphometric data. We further provide an immunohistochemistry procedure to assess colocalization of isolated astrocytes with synaptic markers throughout the z-plane. This technique, which can be utilized via a standard laboratory confocal microscope and Imaris software, allows for detailed analysis of the morphology and synaptic colocalization of astrocytes in fixed tissue. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Microinjection of AAV5-GfaABC1D-Lck-GFP into the nucleus accumbens of rats Basic Protocol 2: Tissue processing and immunohistochemistry for post-synaptic density-95 Basic Protocol 3: Single-cell image acquisition Basic Protocol 4: Three-dimensional reconstruction of single cells Basic Protocol 5: Three-dimensional colocalization analysis.

A214 GENETIC VARIATION IN THE FARNESOID X RECEPTOR PREDICTS CROHN’S DISEASE SEVERITY IN FEMALE PATIENTS

Background

Crohn’s disease (CD) is an immune-mediated inflammatory bowel disease defined by episodes of intestinal inflammation. There is now an increasing appreciation of the bile acid-sensing nuclear receptor, FXR, as an important regulator of intestinal inflammation, intestinal permeability and response to bacterial overgrowth. Many of these processes are dysregulated in CD. It is unclear how genetic variation in FXR impacts on CD severity. FXR deficiency is rare. Loss of function mutations in FXR as contributors to CD are unlikely; however, partial loss of function of FXR may contribute to CD progression or severity. Our group demonstrated that FXR-1G&gt;T, a SNV adjacent to the ATG start codon, is linked to reduced transactivation of FXR gene targets. We hypothesized that changes in the intestinal barrier as a result of reduced FXR expression among those who harbor the FXR-1T allele are more likely to exhibit a severe CD phenotype compared to G (reference) allele carriers, and thereby experience a more rapid progression to surgery. Alterations in FXR activity may in part be secondary to genetic variation in the FXR gene.

Aims

To evaluate FXR-1G&gt;T as a genomic biomarker of severity in CD and propose a plausible molecular mechanism.

Methods

A retrospective study (n=542) was conducted in a Canadian cohort of CD patients. Blood samples were obtained for genotypic analysis (FXR-1G&gt;T), as well as determination of the FXR downstream product, fibroblast growth factor (FGF) 19. Primary outcomes included risk and time to first CD-related surgery. To better elucidate a potential molecular basis for the observed effect of FXR-1G&gt;T genotype on CD prognosis (more frequent and early surgery) in female CD patients, we explored a connection between the estrogen receptor (ER)-mediated pathway and genetic variation in FXR using a cell-based model. .

Results

The FXR-1GT genotype was associated with the risk of (odds ratio, OR=3.34, 95%CI=1.58–7.05, p=0.002) and early progression to surgery (hazard ratio, HR=3.00, 95%CI=1.86–4.83, p&lt;0.0001) in CD. Female carriers of the FXR-1GT genotype had the greatest risk of surgery (OR=14.87 95%CI=4.22–52.38, p&lt;0.0001) and early progression to surgery (HR=6.28, 95%CI=3.62–10.90, p&lt;0.0001). Furthermore, women carriers of FXR-1GT polymorphism had a nearly three-fold lower FGF19 plasma concentration compared to women with wildtype FXR-1GG genotype (p&lt;0.0001). In HepG2 cells cotransfected with estrogen receptors (ERα and β) and FXR, presence of estradiol further attenuated variant FXR activity.

Conclusions

FXR-1GT is deleterious to women with CD through ER-mediated attenuation of FXR activation. Female CD FXR-1GT carriers should be considered for more aggressive medical management.

Funding Agencies

CAG, CCC, CIHR

A208 HLA-DQA1*05 GENOTYPE PREDICTS ANTI-DRUG ANTIBODY FORMATION AND LOSS OF RESPONSE DURING INFLIXIMAB THERAPY FOR INFLAMMATORY BOWEL DISEASE

Background

The underlying mechanism for immunogenicity in anti-TNFa-exposed patients with inflammatory bowel disease is poorly understood. Anti-drug antibodies are a leading contributor to infliximab loss of response and adverse drug events. Currently, it is not feasible to identify patients at risk of antibody formation prior to initiating infliximab. The genetic variation HLADQA1*05(rs2097432) has been linked to infliximab antibody formation in a cohort of patients with Crohn’s disease.

Aims

Due to the wide variation in the frequency of HLADQA1* 05 across ethnic groups, we aim to independently evaluate the association between HLADQA1*05and infliximab antibody formation, infliximab loss of response, treatment discontinuation and adverse drug events, in a Canadian inflammatory bowel disease cohort.

Methods

In a retrospective cohort study, infliximab-exposed patients with inflammatory bowel disease (n=262) were screened for the genetic variation, HLADQA1*05A&gt;G(rs2097432). The risk of infliximab anti-drug antibody formation, infliximab loss of response, adverse events, and discontinuation were assessed in wild type (GG) and variant-carrying (AG or AA) individuals.

Results

Forty percent of all participants were HLADQA1*05A&gt;Gvariant carriers, with 79% of participants with infliximab antibodies carrying at least one variant allele. The risk of infliximab antibody formation was higher in HLADQA1*05A&gt;Gvariant carriers in an IBD population (adjusted HR=7.29, 95%CI=2.97–17.191, p=1.46x10-5) independent of age, sex, weight, dose and co-immunosuppression with an immunomodulator. Variant carrier status was associated with an increased risk of infliximab loss of response (adjusted HR=2.34, 95%CI=1.41–3.88, p=0.001) and discontinuation (adjusted HR=2.27, 95%CI=1.46–3.43, p=2.53x10-4) though not with infliximab-associated adverse drug events.

Conclusions

HLADQA1*05 is independently associated with a high risk of infliximab antibody formation in addition to infliximab loss of response and treatment discontinuation. As a result, we propose that pre-emptive genetic screening for the HLADQA1* 05A&gt;Gvariant would be useful in order to predict individuals at risk of developing immunogenicity. There may be a role for genotype-guided application of combination therapy in inflammatory bowel disease.

Funding Agencies

NoneWolfe Medical Research Chair in Pharmacogenomics (MOP-89753 to RBK), the Academic Medical Organization of Southwestern Ontario (INN18-005 to RBK and AW; S17-004 to AW), and Lawson Health Research Institute (IRF-05-19 to AW)

Erythroderma with circulating atypical T-cells, likely Sézary syndrome

The erythrodermic patient is often challenging and requires careful evaluation. Work-up should include an extensive and careful medication history, histological and laboratory testing, and if necessary, molecular studies for the evaluation of underlying malignancy. Herein, we present an erythrodermic patient with repeated biopsies demonstrating a spongiotic process who was found to have circulating atypical T-cells concerning for an underlying erythrodermic T-cell leukemia, most closely related to Sézary syndrome.