bluuebunny/crossref_metadata_2025_split huggingface dataset:
SAT006 Activation Of The CAR/RXR Heterodimer By Pesticides And Induced Metabolic Effects
Authors: Dauwe Yannick , Lakhal Laila 
Published: October 2023

Abstract
Disclosure: Y. Dauwe: None. L. Lakhal: None.
The nuclear receptor Constitutive Androstane Receptor (CAR or NR1I3) was initially reported as a transcription factor regulating the hepatic genes involved in detoxication function. Thereby CAR protects against xenobiotics but also endogenous molecules such as biliary acid, bilirubin, thyroids and steroids hormones. Different studies showed that CAR activation results in metabolic disorders including Non-Alcoholic Fatty Liver Disease (NAFLD) by promoting lipogenesis in the liver. Environmental contaminants referred to as endocrine disrupting chemicals are suspected to be involved in the increased incidence of metabolic disorders through the activation of nuclear receptors such as CAR and PXR. Previous in vitro studies have shown that the synergistic activation of the Pregnane X Receptor (PXR) by two PXR ligands is potentiated in presence of a Retinoid X Receptor (RXR) environmental ligand, tributyltin (TBT). The objective of our study was to determine whether the synergic activation of PXR/RXR observed in vitro could be transposed in vivo with environmental chemicals on the PXR/RXR and CAR/RXR heterodimers. But also, to asses if this activation could exacerbate the metabolic effects. In that aim, binary mixtures of six, CAR and PXR ligands, pesticides and TBT were first orally administrated to C57BL/6 mice for 3 days, each close to the minimal dose able to activate CAR which was determined in a previous dose response study. A synergistic activation of the CAR/RXR heterodimer by pesticides in combination with TBT was observed on the expression of prototypical CAR target gene Cyp2b10 and on genes involved in lipid metabolism. Combined effects where observed on lipid accumulation in the liver. A synergic elevation of plasma cholesterol was observed and decreased free fatty acid levels were also evidenced for some pesticides in combination with TBT. Two mixtures of five pesticides ligand of CAR and PXR with or without TBT, each at the No Observed Adverse Effect Level (NOAEL), were then administered for 120 days to determine if these threshold safe doses are underestimated in the context of human chronic exposure to a mixture of endocrine disrupting chemicals. The experiment was performed with wild type, CAR null and PXR null mice to check the involvement of nuclear receptors in the measured effects. We observed an activation of CAR by the pesticide cocktail alone or in combination with TBT. The cocktail effect is now tested on the expression of genes involved in lipid metabolism, circulating plasma lipids, lipid accumulation in the liver as well as inflammation and fibrosis. Our first results show an increased transcription of lipogenic genes but no significant effects on lipid plasma levels. Considering these cooperative effects of pesticides may help refine risk assessment, which could lead to a better prevention policy.
Presentation: Saturday, June 17, 2023
SAT007 Excess Bile Acids Can Compensate To Promote Regeneration In Constitutive Androstane Receptor Knockout Mice
Authors: Zhou Weinan , Chembazhi Ullas V , Huang Jiansheng , Bangru Sushant , Dean Angela E , Kalsotra Auinash , Rudnick David A , Anakk Sayeepriyadarshini 
Published: October 2023

Abstract
Disclosure: W. Zhou: None. U.V. Chembazhi: None. J. Huang: None. S. Bangru: None. A.E. Dean: None. A. Kalsotra: None. D.A. Rudnick: None. S. Anakk: None.
The liver plays a key role for the metabolism of nutrients and xenobiotics. Nuclear receptor constitutive androstane receptor (CAR) regulates the transcription of detoxification and proliferation genes. The liver can also regenerate, which can be tested using a model of 2/3rd partial hepatectomy (PHx). We investigated the role for CAR during liver regeneration by mining publicly available single-cell RNA seq data after PHx. Car and its target expression was enriched in hypermetabolic hepatocytes, which was unexpected since based on previous studies we anticipated a proliferative role for CAR. We also examined liver weight, hepatocyte proliferation, and levels of bile acid (BAs) and liver enzymes in Car knockout (CarKO) and wild-type (WT) mice after PHx, and found them comparable between the two genotypes. Intriguingly, we noted a dramatic BA overload and concomitant changes in the expression of genes responsible for BA synthesis and detoxification in CarKO mice after PHx. This led us to speculate if the BA excess observed in CarKO mice after PHx promoted regeneration. When this excess BAs was reduced with a resin treatment in CarKO mice, we found deficits in proliferation and Yes-associated protein signaling demonstrating that elevated BAs act as mitogens to counteract the regenerative defects in CarKO livers.
Presentation: Saturday, June 17, 2023
SAT014 Involvement Of Cytochrome P450 1B1 In Synthesis Of Neurosteroid Pregnenolone In Human Brain Cells
Authors: Christina Lin Yiqi , Cheung Garett , Zhang Zeyu , Papadopoulos Vassilios 
Published: October 2023

Abstract
Disclosure: Y. Lin: None. G. Cheung: None. Z. Zhang: None. V. Papadopoulos: None.
Neurosteroids, steroids synthesized in the nervous system, have important functions in modulating brain function, neuroprotection, and reducing neuroinflammation. The neurosteroid pregnenolone, the precursor to all other neurosteroids, is one of the most abundant neurosteroids in the brain. Still, the enzyme known to make it, CYP11A1, has been difficult to detect in the human brain. We recently reported that unlike in peripheral steroidogenic organs, pregnenolone is not synthesized by CYP11A1 in human brain cells but rather by another mitochondrial cytochrome P450 enzyme (J Biol Chem. 2022 Jul;298(7):102110). Therefore, we aimed to identify the enzyme responsible for producing pregnenolone in the current study. Upon bioinformatic analyses of publicly available datasets for mitochondrial CYP450s expressed in the human brain, we identified three potential candidates: CYP27A1, CYP1A1, and CYP1B1. Given that CYP27A1 is highly expressed in the brain and is involved in cholesterol metabolism, we first tested the effects of CYP27A1 inhibition via drug treatment and siRNA knockdown on pregnenolone synthesis in steroidogenic MGM-1 human glioma cells. Neither treatment with CYP27A1 inhibitors anastrozole or dexmedetomidine nor CYP27A1 siRNA knockdown resulted in a significant reduction in pregnenolone formation by MGM-1 cells, suggesting that CYP27A1 likely is not involved in pregnenolone synthesis in human brain cells. On the other hand, MGM-1 cells treated with the CYP1A1/CYP1B1 inhibitors α-napthoflavone and 2,4,3’,5’-tetramethoxystilbene showed a significant reduction in pregnenolone production in the presence of the pregnenolone precursor 22R-hydroxycholesterol. To investigate whether this effect was due to the inhibition of CYP1A1 or CYP1B1, we knocked down CYP1A1 or CYP1B1 in MGM-1 cells using siRNA. While CYP1A1 knockdown did not result in any significant changes to pregnenolone synthesis, CYP1B1 knockdown significantly decreased secreted pregnenolone formation by MGM-1 cells. Together, these results suggest that CYP1B1 is likely involved in the alternative pathway for pregnenolone synthesis in human brain cells.
Presentation: Saturday, June 17, 2023
SAT018 Investigate If Sex Differences In Microbiota Is Sufficient To Promote Bile Acid-Mediated Hepatocellular Carcinoma In Mice
Authors: Dean Angela E , Gaulke Christopher A , Anakk Sayeepriyadarshini 
Published: October 2023

Abstract
Disclosure: A.E. Dean: None. S. Anakk: None.
Liver cancer is one of the leading causes of cancer-related deaths with men having a higher prevalence than women. It is becoming clearer that changes in bile acid levels are seen in patients diagnosed with liver cancer. Although initially made in the liver, these primary bile acids can also be modified by bacteria in the intestines to form secondary bile acids. The secondary bile acids are more hydrophobic and cytotoxic and when in excess, can promote tumorigenesis. We, therefore, examined if microbial differences between males and females explain sex-dependent HCC development when bile acid metabolism is altered. In this study, we used a mouse model of bile acid excess and HCC, where the bile acid-related nuclear receptors, farnesoid X receptor (Fxr) and small heterodimer partner (Shp), are knocked out. This double knockout (DKO) model mimics the cancer incidence observed in humans, where male mice are more susceptible to spontaneous tumorigenesis than females at 12 months of age. The circulating bile acid profiles of the male DKO mice are more hydrophobic and have a greater proportion of secondary bile acids than the females. Since we observed changes in the bile acid composition, we next investigated if fecal and cecal microbial profiles of male and female DKO mice differed, along with their wild-type counterparts. 16s rRNA full-length sequencing was performed on fecal and cecal samples from 12-month-old mice, and analyses are currently ongoing. We expect that the microbes identified in the male DKO mice will reflect their bile acid compositions, as well as spontaneous tumorigenesis. Additionally, we are analyzing the 16s rRNA gene from mice treated with cholestyramine (CHR), a bile acid binding resin, that exhibit decreased tumorigenesis at 12 months of age. In this manner, we can correlate microbiota changes to the bile acid composition, as well as the extent of tumor burden. Thus, this study will be able to integrate how sex differences in liver cancer incidence can be secondary to microbial modification of bile acids.
Presentation: Saturday, June 17, 2023
SAT019 Ligand-independent Signaling And Migration Of Breast Cancer Cells Overexpressing Membrane Androgen Receptor, ZIP9
Authors: Thomas Peter 
Published: October 2023

Abstract
Disclosure: P. Thomas: None.
The zinc transporter ZIP9 also functions as a membrane androgen receptor (mAR) that mediates androgen-dependent rapid signaling and pro- or anti-apoptotic, proliferative, and migratory responses in fish, rodent, and human cells. Testosterone activation of ZIP9 in two triple-negative breast cancer cell lines, MDA-MB-468 cells and MDA-MB-231 cells transfected with ZIP9 (231-ZIP9), induces G-protein-dependent second messenger signaling and increases in intracellular free zinc. However, the relative importance of these two signaling pathways in the regulation of pro- and anti-tumorigenic responses in these cell lines is unclear because both androgen signaling and zinc status influence tumorigenesis in breast tissues. The effects of overexpression of ZIP9 on free zinc status, G protein- and zinc-dependent regulation of migration, and migration marker expression in 231-ZIP9 cells in the absence of testosterone were compared to those observed in MDA-MB-231 cells transfected with vector alone (231-vect). Migration and invasion of 231-ZIP9 cells were significantly increased after 24-48 hr culture in serum-free media compared to 231-vect cells which was accompanied by a significant increase in free zinc levels. Treatment of 231-vect cells with a zinc ionophore also increased migration, whereas migration of 231-ZIP9 cells was attenuated by treatment with an intracellular zinc chelator, TPEN. Expression of the migration markers, MYL9 and CYR61, was increased in 231-ZIP9 after 24-48 hr culture, whereas expression of apoptotic markers was decreased compared to 231-vect controls. Proximity Ligation Analysis revealed that ZIP9 is closely associated with a stimulatory G protein (Gs) in 231-ZIP9 cells which is consistent with the finding that treatment with the adenylyl cyclase (AC) stimulator forskolin, further increased migration marker expression and migration compared to vehicle controls, whereas the PKA inhibitor, H-89, attenuated these responses as well as the increase in free zinc concentrations. Knockdown of ZIP9 expression in MDA-MB-468 cells which express relatively high levels of ZIP9 with siRNA decreased cell migration and invasion as well as free zinc levels, confirming a role of unliganded ZIP9 in migration in another breast cancer cell line. Treatment of 231-ZIP9 cells with 100 nM testosterone further stimulated CYR61 and MYL9 expression and cell migration which were blocked by co-treatment with a Gs inhibitor and TPEN. The results indicate that high ZIP9 expression in breast cancer cells causes androgen-independent increased cell migration and invasion which in 231-ZIP9 cells is through Gs/mAC/PKA-mediated increases in intracellular zinc concentrations and upregulation of MYL9 and CYR-61 expression. Furthermore, the results suggest that testosterone-dependent signaling through ZIP9 acts through the same pathways to further enhance signaling and migration.
Presentation: Saturday, June 17, 2023
OR22-06 Functional Characterization Of X-linked Genes In Regulating Epigenetic Landscape In Endocrine-resistant Breast Cancer
Authors: Ivan Ramos Enrique , Yang Barbara , Sedano Melina , Reid Victoria , Diwa Kimberly , Hidalgo Axel , Beard Alexandra , Patel Jai , Gadad Shrikanth S 
Published: October 2023

Abstract
Disclosure: E.I. Ramos: None. B. Yang: None. M. Sedano: None. V. Reid: None. K. Diwa: None. A. Hidalgo: None. A. Beard: None. J. Patel: None. S.S. Gadad: None.
Studies show that genes transcribed from chromosome X play critical roles in several biological processes. X-linked genes are tightly regulated and expressed in tissues protected from immune surveillance. However, several of them get dysregulated in diseases such as cancer. Intriguingly, genome-wide analyses showed their presence in the previously considered gene deserts in the human genome. Their direct role in estrogen transcription in tamoxifen-resistant breast cancer and biological outcomes are still unknown. To this end, we leveraged the power of functional genomics, including RNA with 4-thiouridine (4sU) coupled with RNA-sequencing and CRISPR-based genetic screening, to identify X-linked genes with a potential role in tamoxifen-directed estrogen-regulated transcription. Through a series of phenotypic assays, we selected a poorly studied transcript, “H19X,” with limited protein-coding potential; RNA-In-Situ-Hybridization revealed its localization to the nucleus. In the current study, we have identified the H19X-controlled estrogen-dependent gene regulatory mechanisms in tamoxifen-resistant estrogen receptor-positive (ER+) breast cancer cells. We manipulated the levels of H19X in tamoxifen-resistant ER+ breast cancer cells to generate a comprehensive list of direct transcripts using 4sU-RNA-seq. Interestingly, H19X regulates the expression of estrogen-driven intergenic, divergent, and antisense transcripts whose promoters are bound by ER-alpha (ERα) binding sites. Mechanistically, ‘Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq)’ revealed that H19X modulates chromatin structure at target regions to control gene expression. In addition, ‘chromatin immunoprecipitation (ChIP) with massively parallel DNA sequencing ChIP-seq’ (H3K27ac, H3K27me3) identified a critical role for H19X in controlling the epigenetic landscape in tamoxifen-resistant ER+ breast cancer cells. Collectively, our study sheds light on the molecular functions of X-linked genes and allows us to identify new diagnostic and therapeutic targets in tamoxifen-resistant ER+ breast cancer.S.S.G. is supported by grants from a) The Cancer Prevention and Research Institute of Texas (CPRIT; RR170020); b) Lizanell and Colbert Coldwell foundation; c) The Edward N. and Margaret G. Marsh Foundation; d) The American Cancer Society
Presentation: Saturday, June 17, 2023
THU672 Fungating And Inflammatory Anaplastic Thyroid Carcinoma In A 64-Year Old Filipino
Authors: Tarrazona - Dominisac Rochelle Anne M , Capuli Isidro Maria Jocelyn 
Published: October 2023

Abstract
Disclosure: R.M. Tarrazona - Dominisac: None. M.C. Isidro: None.
Background: Anaplastic Thyroid Carcinoma is a rare and lethal undifferentiated thyroid cancer that occurs in less than 2% of all thyroid malignancies. In the Philippines, this rare entity has an estimated incidence of 0.7%. Its aggressive nature is strikingly significant because it carries a poor prognosis with a median survival of 5-6 months. An exceptionally rare presentation of an Anaplastic Thyroid Carcinoma is a fungating, exophytic and inflammatory type. Case Summary: This is a case of a 64-year old female with a 2 x 2 cm erythematous patch at her anterior neck. There is progressive enlargement of the reddish neck lesion associated by burning sensation with subsequent development whitish nodules with purulent exudate. The nodules were fragile with noted bleeding on minimal manipulation. Initial impression was anterior neck cellulitis and she was given 7 days of IV antibiotics with no resolution of the lesion. Neck CT scan showed a multinodular heterogeneously enhancing mass in the left neck region measuring 6.3 x 5.2 x 5.5 cm. A core needle biopsy of the mass revealed malignant cells present: anaplastic carcinoma vs squamous cell carcinoma, with immunohistochemical stains: PAX 8 positive, p63 negative, CK 5/6 negative, BRAF negative, TTF-1 focally positive. The patient underwent tumor debulking surgery with tracheostomy. The gross specimen was sent for histopathologic examination and finally revealed Anaplastic Thyroid Carcinoma. Conclusion: The case reported was a diagnostic dilemma early during the clinical presentation due to presence of rapidly enlarging, inflammatory and fungating anterior neck mass with presence of whitish nodules with purulent exudates, bleeding and pain. She was initially treated as an abscess only to discover presence of malignancy upon further work-up. Anaplastic thyroid cancer is the most advanced and aggressive thyroid malignancy. It is very rare and the atypical fungating presentation of this ATC makes it an exceptionally rare entity. Fungating wounds are the result of cancer cells infiltrating and invading the cutaneous structure. This case report highlights the importance of harnessing a high level of clinical suspicion for anaplastic thyroid cancer even in atypical looking anterior neck mass to ensure prompt definitive diagnosis and improve overall prognosis.
Presentation: Thursday, June 15, 2023
FRI471 Regulation Of Adult Thyroid Hormone Homeostasis By Early Postnatal Hyperthyroidism In Male Mice
Authors: Kovári Dóra , Szilvásy-Szabó Anett , Penksza Veronika , Gereben Balazs , Fekete Csaba 
Published: October 2023

Abstract
Disclosure: D. Kovári: None. A. Szilvásy-Szabó: None. V. Penksza: None. B. Gereben: None. C. Fekete: None.
The thyroid hormone (TH) negative feedback regulation enables the hypothalamic-pituitary-thyroid (HPT) axis to maintain the relatively steady circulating TH levels. Internal and external factors influence the development of this feedback regulation and consequently evoke life-long changes of the HPT axis activity. The aim of our study was to reveal how perinatal alteration of TH status influences TH homeostasis of adult mice. Mice were treated with 1µg/bwg thyroxine (T4) or vehicle subcutaneously every day between postnatal day (P) 2-6 and sacrificed at adulthood. Early postnatal hyperthyroidism resulted in central hypothyroidism in adults, characterized by decreased thyrotropin releasing hormone (TRH) mRNA expression in the hypothalamic paraventricular nucleus (PVN) and lower serum free T4 level, accompanied by unchanged thyrotropin stimulating hormone β (TSHβ) mRNA expression in the pituitary and serum free triiodothyronine level. The two main regulators of the HPT axis are the hypophysiotropic TRH neurons and tanycytes. Tanycytes affect the feedback regulation of TRH neurons by type 2 deiodinase (D2) mediated TH activation. To understand how postnatal T4 treatment results in central hypothyroidism in adult mice, tanycytes and TRH neurons of the PVN were isolated by laser capture microdissection from control and postnatally T4 treated adult mice. Postnatal T4 treatment did not change D2 expression in the tanycytes. Furthermore, using Thyroid Hormone Action Indicator (THAI) mice, we showed that the treatment did not influence TH action in the mediobasal hypothalamus of adult mice. These data together indicate that tanycytes are not involved in mediation of the postnatal T4 treatment induced effects. In contrast, the early postnatal T4 treatment markedly changed the transcriptome of TRH neurons in the PVN of adult mice. The expression of TH receptors, most TH receptor-related coregulators, TH transporters and genes involved in the synthesis of TRH were decreased. Despite of the central hypothyroidism, the energy expenditure of these mice were not decreased and TH action also remained unchanged in most tissues indicating that the peripheral tissues are able to compensate the effect of the generated mild hypothyroidism. These results indicate that alteration of TH levels during the early postnatal period can cause life-long effects on the activity of the HPT-axis likely via epigenetic regulation of TRH neurons.
Presentation: Friday, June 16, 2023
FRI472 Thyroid Hormone Resistance β (RTH- β) Syndrome In Patient With Multiple-system Atrophy Parkinsonian Type (MSA-P)
Authors: Lio Serafino , Albin Monica , Campi Irene , Persani Luca 
Published: October 2023

Abstract
Disclosure: S. Lio: None. M. Albin: None. I. Campi: None. L. Persani: None.
Background: Resistance to thyroid hormone β (RTHβ) is a rare dominantly inherited condition of impaired tissue responsiveness to thyroid hormones (TH) due to variants in the THRB gene encoding the TH receptor β (TRβ). RTHβ patients display a distinctive biochemical feature of central hyperthyroidism with elevated serum levels of FT3 and FT4 and unsuppressed TSH. Unfortunately, this syndrome is sometimes misdiagnosed as primary hyperthyroidism, with a delayed diagnosis or inappropriate treatments. Clinical Case: A 72-year-old lady was diagnosed elsewhere in 2010 with atrial fibrillation (AF) and parkinsonian multisystem atrophy (MSA-P), an orphan disease causing progressive autonomic and motor impairment. The patient reported an unspecified dysthyroidism discovered during the diagnostic work-up of AF, but no further investigations were performed. Bisoprolol, Edoxaban and Levodopa/Benserazide were started. In 2020 she had multiple hospitalization due to fall-related injuries, and multiple rib fractures. A neurological and cardiological reassessment did not highlight new problems, nor MSA-P progression, while discrepant thyroid function tests (TFTs) were found (TSH 2.4 mU/L, fT4 3.5 ng/dl, fT3 7.9 pg/ml; normal ranges: 0.4-4.5; 0.8-1.7 and 2.-5, respectively). Anterior pituitary function and a gadolinium-enhanced pituitary MRI were normal. Thyroid ultrasound revealed a modest goiter, with a normal vascularization and multiple hypo-anechoic and spongiform nodules ≤1 cm. Propylthiouracil has been started At referral in our Center, discrepant TFTs were confirmed (TSH 6.6 mU/L, fT4 2.5 ng/dL, fT3 5.1 pg/ml). TPOAb, TgAb and TRAb were absent. We also excluded assay interferences due to heterophiles antibodies. Being T3 administration contraindicated due to AF, a TRH-test, after suspension of PTU, was performed showing an intense and prolonged response of the TSH (36.7 and 19.2 mU/L at 30 and 120 minutes, respectively), consistent with RTHβ. Consistently, molecular analysis by a targeted NGS panel revealed a heterozygous known pathogenic variant in the exon 9 of the TRHB gene (c.1033G&gt;A, p.Gly345Ser). Conclusion: In the differential diagnosis of central hyperthyroidism RTHβ should be considered even in older patients, as late diagnosis may occur. The association of RTHβ with MSA-P has never been reported before, although a causal relationship is improbable. Nevertheless, central hyperthyroidism could worsen underlying neurological diseases, given the critical role of TH in CNS and muscle. A greater awareness of both neurologists and endocrinologists on rare thyroid diseases is warranted, to improve the care of patients with neurological orphan diseases.
Presentation: Friday, June 16, 2023