T-bet Research Articles

Correlation of TBX21 gene polymorphisms with ankylosing spondylitis in a Chinese population.

Genome-wide association studies analysis has revealed associations between ankylosing spondylitis (AS) and loci on the TBX21 gene across various populations. This study aimed to investigate if there is a connection between a higher risk of AS in a Chinese population and two polymorphism loci on the TBX21 gene. To achieve this, we performed a case-control investigation involving 363 patients with AS and 907 healthy individuals. Genotyping was carried out using the iPLEX Gold genotyping assay. The analysis of genotypes and haplotypes was performed using SPSS 23.0 and SHEsis software. The results revealed no statistically significant correlation between the two specified single-nucleotide polymorphisms of TBX21 (rs11657479 C/T and rs4794067 C/T) and susceptibility to AS. However, upon conducting stratification analysis, our findings demonstrated a significant association between rs11657479 and susceptibility to human leucocyte antigen (HLA)-B27+ AS in allelic (C vs. T: odds ratio [OR]=1.52, 95%CI=1.09-2.11, corrected p [pc]=.028), heterozygous (CT vs. TT: OR=1.63, 95%CI=1.13-2.34, pc=.016) and dominant (CT+CC vs. TT: OR=1.60, 95%CI=1.12-2.28, pc=.018) models. Furthermore, the haplotype rs4794067/C-rs11657479/C of TBX21 was found to increase the risk of HLA-B27+ AS cases. In conclusion, our findings indicate a correlation between TBX21 gene polymorphism and HLA-B27+ AS patients within the Chinese population.

Gene Expression Studies in Down Syndrome: What Do They Tell Us about Disease Phenotypes?

Down syndrome is a well-studied aneuploidy condition in humans, which is associated with various disease phenotypes including cardiovascular, neurological, haematological and immunological disease processes. This review paper aims to discuss the research conducted on gene expression studies during fetal development. A descriptive review was conducted, encompassing all papers published on the PubMed database between September 1960 and September 2022. We found that in amniotic fluid, certain genes such as COL6A1 and DSCR1 were found to be affected, resulting in phenotypical craniofacial changes. Additionally, other genes such as GSTT1, CLIC6, ITGB2, C21orf67, C21orf86 and RUNX1 were also identified to be affected in the amniotic fluid. In the placenta, dysregulation of genes like MEST, SNF1LK and LOX was observed, which in turn affected nervous system development. In the brain, dysregulation of genes DYRK1A, DNMT3L, DNMT3B, TBX1, olig2 and AQP4 has been shown to contribute to intellectual disability. In the cardiac tissues, dysregulated expression of genes GART, ETS2 and ERG was found to cause abnormalities. Furthermore, dysregulation of XIST, RUNX1, SON, ERG and STAT1 was observed, contributing to myeloproliferative disorders. Understanding the differential expression of genes provides insights into the genetic consequences of DS. A better understanding of these processes could potentially pave the way for the development of genetic and pharmacological therapies.

A Pilot Study of Multiplex Ligation-Dependent Probe Amplification Evaluation of Copy Number Variations in Romanian Children with Congenital Heart Defects.

Congenital heart defects (CHDs) have had an increasing prevalence over the last decades, being one of the most common congenital defects. Their etiopathogenesis is multifactorial in origin. About 10-15% of all CHD can be attributed to copy number variations (CNVs), a type of submicroscopic structural genetic alterations. The aim of this study was to evaluate the involvement of CNVs in the development of congenital heart defects. We performed a cohort study investigating the presence of CNVs in the 22q11.2 region and GATA4, TBX5, NKX2-5, BMP4, and CRELD1 genes in patients with syndromic and isolated CHDs. A total of 56 patients were included in the study, half of them (28 subjects) being classified as syndromic. The most common heart defect in our study population was ventricular septal defect (VSD) at 39.28%. There were no statistically significant differences between the two groups in terms of CHD-type distribution, demographical, and clinical features, with the exceptions of birth length, weight, and length at the time of blood sampling, that were significantly lower in the syndromic group. Through multiplex ligation-dependent probe amplification (MLPA) analysis, we found two heterozygous deletions in the 22q11.2 region, both in patients from the syndromic group. No CNVs involving GATA4, NKX2-5, TBX5, BMP4, and CRELD1 genes were identified in our study. We conclude that the MLPA assay may be used as a first genetic test in patients with syndromic CHD and that the 22q11.2 region may be included in the panels used for screening these patients.

In-silico identification of deleterious non-synonymous SNPs of TBX1 gene: Functional and structural impact towards 22q11.2DS.

The TBX1 gene plays a critical role in the development of 22q11.2 deletion syndrome (22q11.2DS), a complex genetic disorder associated with various phenotypic manifestations. In this study, we performed in-silico analysis to identify potentially deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) within the TBX1 gene and evaluate their functional and structural impact on 22q11.2DS. A comprehensive analysis pipeline involving multiple computational tools was employed to predict the pathogenicity of nsSNPs. This study assessed protein stability and explored potential alterations in protein-protein interactions. The results revealed the rs751339103(C>A), rs780800634(G>A), rs1936727304(T>C), rs1223320618(G>A), rs1248532217(T>C), rs1294927055 (C>T), rs1331240435 (A>G, rs1601289406 (A>C), rs1936726164 (G>A), and rs911796187(G>A) with a high-risk potential for affecting protein function and stability. These nsSNPs were further analyzed for their impact on post-translational modifications and structural characteristics, indicating their potential disruption of molecular pathways associated with TBX1 and its interacting partners. These findings provide a foundation for further experimental studies and elucidation of potential therapeutic targets and personalized treatment approaches for individuals affected by 22q11.2DS.

Genetic and functional variants of the TBX20 gene promoter in dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a major cause of heart failure and sudden cardiac death. As DCM is a genetically heterogeneous disease, genetic variants of cardiac transcription factor genes may play an important role. Transcription factor TBX20, an indispensable factor in normal heart development, is involved in the regulation of cardiac structure and function. Although the TBX20 gene is associated with the occurrence and development of DCM, the influence of genetic variants of the TBX20 gene promoter region on DCM has not been reported. We conducted a case-control study consisting of 107 DCM patients and 210 healthy controls. Genetic variants within TBX20 gene promoter region were identified using sequencing techniques and were functionally analyzed by dual-luciferase reporting assay. Electrophoretic mobility shift assay (EMSA) was used to investigate DNA-protein interactions. In this study cohort (n = 317), we identified eight variants within TBX20 gene promoter. One novel DNA sequence variants (DSV) (g.4275G>T) and four single-nucleotide polymorphisms (SNPs) [g.4169G>A (rs1263874255), g.4949C>T (rs1191745927), g.5114G>A (rs112076877), g.5252C>T (rs1356932911)] were identified in DCM patients, but in none of controls. Among them, the DSV (g.4275G>T) and three SNPs [g.4949C>T (rs1191745927), g.5114G>A (rs112076877) and g.5252C>T (rs1356932911)] significantly altered the transcription activity of TBX20 gene promoter by dual-luciferase reporting assay (p < 0.05). Further, EMSA assay indicated that the DSV (g.4275G>T) and three SNPs [g.4949C>T (rs1191745927), g.5114G>A (rs112076877) and g.5252C>T (rs1356932911)] affected the binding of transcription factors. These data indicate that the DSV (g.4275G>T) and three SNPs [g.4949C>T (rs1191745927), g.5114G>A (rs112076877) and g.5252C>T (rs1356932911)] increase transcription activity of TBX20 gene promoter in both HEK-293 and neonatal rat cardiomyocytes (NRCMs) cell lines by affecting the binding of transcription factors. But the mechanism remains to be verified invivo.

Acute Post Streptococcal Glomerulonephritis with Persistent Hypertension in a Child of Holt-oram Syndrome: A Case Report

Holt-Oram syndrome is a rare congenital autosomal dominant disorder caused by a mutation in the TBX5 gene. It is characterised by upper limb abnormalities and congenital heart lesions, such as Atrial Septal Defect (ASD), typically affecting children. In this case, a sixyear-old boy presented with facial puffiness and decreased urine output following an upper respiratory infection. Upon examination, he was found to have Holt-Oram syndrome, a rare genetic disorder characterised by abnormalities in the bones of the upper limbs and congenital heart defects. He developed acute Post Streptococcal Glomerulonephritis (PSGN) following a streptococcal infection, resulting in persistent hypertension. Each condition independently poses significant health challenges, and their simultaneous occurrence complicates the clinical picture considerably. Following detailed investigations and management, the child required continued treatment with two antihypertensive medications upon discharge. The need for dual therapy in a paediatric patient highlights the severity of his condition and the challenges in managing it effectively. Close follow-up is essential to monitor disease progression and ensure optimal outcomes. This case features both a genetic disorder (Holt-Oram syndrome due to a TBX5 gene mutation) and an immune-mediated renal disease (PSGN), representing a rare intersection of genetic and postinfectious pathologies. The co-existence of these two conditions is unusual and complicates the clinical picture, necessitating a tailored approach to management. This case underscores the need for a multidisciplinary approach involving cardiology, nephrology, and genetics. Coordinated care is crucial for monitoring disease progression, managing complications, and ensuring comprehensive treatment.

Establishment of the Myeloid TBX-Code Reveals Aberrant Expression of T-Box Gene TBX1 in Chronic Myeloid Leukemia.

T-box genes encode transcription factors, which control developmental processes and promote cancer if deregulated. Recently, we described the lymphoid TBX-code, which collates T-box gene activities in normal lymphopoiesis, enabling identification of members deregulated in lymphoid malignancies. Here, we have extended this analysis to cover myelopoiesis, compiling the myeloid TBX-code and, thus, highlighting which of these genes might be deregulated in myeloid tumor types. We analyzed public T-box gene expression datasets bioinformatically for normal and malignant cells. Candidate T-box-gene-expressing model cell lines were identified and examined by RQ-PCR, Western Blotting, genomic profiling, and siRNA-mediated knockdown combined with RNA-seq analysis and live-cell imaging. The established myeloid TBX-code comprised 10 T-box genes, including progenitor-cell-restricted TBX1. Accordingly, we detected aberrant expression of TBX1 in 10% of stem/progenitor-cell-derived chronic myeloid leukemia (CML) patients. The classic CML cell line K-562 expressed TBX1 at high levels and served as a model to identify TBX1 activators, including transcription factor GATA1 and genomic amplification of the TBX1 locus at 22q11; inhibitors, including BCR::ABL1 fusion and downregulated GNAI2, as well as BMP, FGF2, and WNT signaling; and the target genes CDKN1A, MIR17HG, NAV1, and TMEM38A. The establishment of the myeloid TBX-code permitted identification of aberrant TBX1 expression in subsets of CML patients and cell lines. TBX1 forms an integral part of an oncogenic regulatory network impacting proliferation, survival, and differentiation. Thus, the data spotlight novel diagnostic markers and potential therapeutic targets for this malignancy.

Evaluation of genetic markers in the analysis of the colors and marks occurrence in the vyatka breed horses

Vyatka breed is a valuable small native breed of horses. The study of the determination of suits is of significant practical importance in breeding. This is especially true for small breeds. The purpose of the research is to monitor the color and markings as important genetic markers of preservation the Vyatka breed gene pool. To meet the objective, the following tasks were set: to evaluate the structure of suits in a microevolutionary aspect and to study the polymorphism of the MC1R and ASIP genes, determine the basic suits, the “lightening” genes TBX3 and MATP, determining the desired suits in the breed, as well as to evaluate the influence of the TBX3 and W20 genes, giving the desirable "wild" markings and undesirable whites. The object of the study is Vyatka horses born in 1975-2022 (n=2949) registered in the breed database. DNA extraction from hair follicles of Vyatka horses (n=86) was carried out in the “HorsGen” laboratory (Moscow) using “ExtraGene DNA Prep” (“Isogen”, Moscow). Single nucleotide polymorphisms (SNPs) were identified by allele-specific PCR. The calculations were performed using MS Excel 10. Prevailing colors in the Vyatka breed - dun (56.9%) and grullo (31.7%). Of commercial interest are the colors determined by the Dun + Cream genes (3.2%). The occurrence of the D/D genotype in the Vyatka breed is low (0.167), so there are non-dun colors (5,2%). All TBX3 genotypes were identified with a predominance of D/nd1 (0.405). The relationship between the TBX3 gene and white markings has not been found, but with a shade of color and “wild” markings, it has been identified. The D/nd1 genotype is more common in medium (0.440) and light (0.714) horses, with D/nd2 (0.455) predominating in darker individuals. Noticeable "wild" markings prevail in horses with the D/nd1 genotype (0.539), their absence was found only in species with D/nd2. The MC1R/EE genotype is predominant in horses without white markings (0.612) and those with small markings (0.500). The occurrence of the W20 allele in Vyatka breed is low (0.146) and affects the size of white marks: the lowest was noted in animals without marks, the highest - with large marks. Since the color is an important genetic marker and selection trait, genotyping of breeding stallions and mares for the set of genes associated with the colors and markings is important.

Chlorella vulgaris extract and Imiquimod as new therapeutic targets for leishmaniasis: An immunological approach

The therapeutic regimen for the treatment of American Tegumentary Leishmaniasis (ATL) is targeted at the death of the parasite; therefore, it is essential to develop a treatment that can act on the parasite, combined with the modulation of the inflammatory profile. Thus, the aim of this study was to make an in vitro evaluation of the therapeutic potential of Chlorella vulgaris extract (CV) and Imiquimod for ATL. Selectivity indices (SI) were determined by inhibitory concentration assays (IC50) in L. braziliensis cells and cytotoxic concentrations (CC50) were measured in human cells using the MTT method, based on the CV microalgae extract (IC50 concentrations of 15.63 to 500 µg/mL; CC50 concentrations of 62.5–1000 µg/mL) in comparison with the reference drugs and Imiquimod. The immune response was evaluated in healthy human cells by gene expression (RT-qPCR) and cytokine production (Flow Cytometry). The CV extract (SI = 6.89) indicated promising results by showing higher SI than meglumine antimoniate (SI = 3.44) (reference drug). In all analyses, CV presented a protective profile by stimulating the production of Th1 profile cytokines to a larger extent than the reference drugs. Imiquimod showed a high expression for Tbx21, GATA3, RORc and Foxp3 genes, with increased production only of the TNF cytokine. Therefore, the data highlight the natural extract and Imiquimod as strong therapeutic or adjuvant candidates against ATL, owing to modulation of immune response profiles, low toxicity in human cells and toxic action on the parasite.

Supraclavicular brown adipocytes originate from Tbx1+ myoprogenitors.

Brown adipose tissue (BAT) dissipates energy as heat, contributing to temperature control, energy expenditure, and systemic homeostasis. In adult humans, BAT mainly exists in supraclavicular areas and its prevalence is associated with cardiometabolic health. However, the developmental origin of supraclavicular BAT remains unknown. Here, using genetic cell marking in mice, we demonstrate that supraclavicular brown adipocytes do not develop from the Pax3+/Myf5+ epaxial dermomyotome that gives rises to interscapular BAT (iBAT). Instead, the Tbx1+ lineage that specifies the pharyngeal mesoderm marks the majority of supraclavicular brown adipocytes. Tbx1Cre-mediated ablation of peroxisome proliferator-activated receptor gamma (PPARγ) or PR/SET Domain 16 (PRDM16), components of the transcriptional complex for brown fat determination, leads to supraclavicular BAT paucity or dysfunction, thus rendering mice more sensitive to cold exposure. Moreover, human deep neck BAT expresses higher levels of the TBX1 gene than subcutaneous neck white adipocytes. Taken together, our observations reveal location-specific developmental origins of BAT depots and call attention to Tbx1+ lineage cells when investigating human relevant supraclavicular BAT.

Abstract A177: In vivo TuBa-seq growth profiling identifies a differential role of the Tbx2 subfamily in oncogene-negative versus Kras-driven lung cancers

Abstract Lung adenocarcinoma (LUAD) is a complex cancer driven by diverse combinations of oncogenic and tumor suppressive events. The TBX2 subfamily genes, including TBX2, TBX3, TBX4, and TBX5, are known to play a crucial role in lung development as master transcriptional regulators. Our previous clinical and in vitro studies found that their expression is significantly suppressed in LUADs, suggesting a potential tumor suppressor role through modulating tumor methylation patterns in early tumorigenesis. However, the role of TBX2 subfamily genes in other cancer types is paradoxical, with both oncogenic and tumor suppressive effects being reported. Herein, we employed the Tumor Barcoding with Ultradeep Sequencing (Tuba-seq) and CRISPR/Cas9-mediated genome editing technologies to investigate the putative tumor suppressive role of TBX2 genes functionally and quantitatively and their downstream targets in genetically engineered mouse models of LUAD. Lung tumors were initiated by intratracheal intubation with pooled lentiviral-Cre vectors targeting each gene independently with two different sgRNAs per gene. To enable the unique identification of each tumor and its corresponding sgRNA, we utilized Lenti-sgRNA/Cre vectors harboring barcodes specific to each targeted gene. Initial assessment of tumor burden was carried out through fluorescence microscopy, lung weight measurements, and histological analysis. To simultaneously determine the number of neoplastic cells corresponding to each gene knockout, the barcoded region was amplified from genomic DNA extracted from bulk tumor-bearing lung samples and sequenced. Quantification of tumor sizes was carried at 6 and 20 weeks after tumor initiation. Hyperplasia, adenomas, and/or early adenocarcinomas within the lungs were detected among different genetic backgrounds and throughout the study time intervals. Specifically, the inactivation of Tbx2, Tbx3, Tbx4, Tbx5, and Cdh2, increased tumor initiation and growth in the oncogene-negative mouse model (n=8). However, strikingly, inactivation of Tbx3, Tbx4, and Cdh2 suppressed tumorigenesis in a KRAS-driven genetic background while Tbx2, Tbx5, and Tnfaip3, consistently exhibited tumor suppressive effects (n=9). Further investigation is needed to understand these newly discovered interactions between the TBX2 subfamily critical developmental pathway and Ras signaling in modulating lung cancer progression. These insights emphasize the importance of considering tumor suppressor phenotypic heterogeneity and their context-dependent roles when developing targeted therapeutic approaches for lung adenocarcinoma and other cancers. Citation Format: Athar Khalil, Mira Rahm, Zachary Faber, Madeline Bedrock, Xiangzhen Wei, Bindi Patel, Christopher Mcfarland. In vivo TuBa-seq growth profiling identifies a differential role of the Tbx2 subfamily in oncogene-negative versus Kras-driven lung cancers [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A177.

Insertion of a FLAG-tag sequence at the end of exon 9 of the TBX5 gene in three induced pluripotent stem cell lines (DHMi004-A-4, DHMi004-A-5, DHMi004-A-6) by CRISPR/Cas9 technology

The identification of TBX5-related regulatory sequences in genes essential for heart development is hampered by the absence of antibodies which allow precipitation of TBX5:DNA complexes. Employing CRISPR/Cas9 technology, we have inserted a FLAG-tag sequence at the end of exon 9 of the TBX5 gene prior to the stop codon by homologous recombination. The translated TBX5-FLAG fusion protein of the three iPSC lines can effectively be precipitated by anti-FLAG antibodies and, thus, allow the detection of specific TBX5-binding sites and their associated genes.

Transcriptome-based comparison reveals key genes regulating allometry growth of forelimb and hindlimb bone in duck embryos

Allometric growth of the forelimb and hindlimb is a widespread phenomenon observed in vertebrates. As a typical precocial bird, ducks exhibit more advanced development of their hindlimbs compared to their forelimbs, enabling them to walk shortly after hatching. This phenomenon is closely associated with the development of long bones in the embryonic stage. However, the molecular mechanism governing the allometric growth of duck forelimb and hindlimb bones is remains elusive. In this study, we employed phenotypic, histological, and gene expression analyses to investigate developmental differences between the humerus (forelimb bone) and tibia/femur (hindlimb bones) in duck embryos. Our results revealed a gradual increase in weight and length disparity between the tibia and humerus from E12 to E28 (embryo age). At E12, endochondral ossification was observed solely in the tibia but not in the humerus. The number of differentially expressed genes (DEGs) gradually increased at H12 vs. T12, H20 vs. T20, and H28 vs. T28 stages consistent with phenotypic variations. A total of 38 DEGs were found across all 3 stages. Protein-protein interaction network analysis demonstrated strong interactions among members of HOXD gene family (HOXD3/8/9/10/11/12), HOXB gene family (HOXB8/9), TBX gene family (TBX4/5/20), HOXA11, SHOX2, and MEIS2. Gene expression profiling indicated higher expression levels for all HOXD genes in the humerus compared to tibia while opposite trends were observed for HOXA/HOXB genes with low or no expression detected in the humerus. These findings suggest distinct roles played by different clusters within HOX gene family during skeletal development regulation of duck embryo's forelimbs versus hind limbs. Notably, TBX4 exhibited high expression levels specifically in tibia whereas TBX5 showed similar patterns exclusively within humerus as seen previously across other species' studies. In summary, this study identified key regulatory genes involved in allometric growth of duck forelimb and hindlimb bones during embryonic development. Skeletal development is a complex physiological process, and further research is needed to elucidate the regulatory role of candidate genes in endochondral ossification.

The role of TBX20 truncating variants in dilated and left ventricular non-compaction cardiomyopathy

Abstract Background The genetic cause of dilated cardiomyopathy (DCM) remains unexplained in a considerable proportion of cases. TBX20, the T-Box transcription factor 20 gene, has been linked to cardiac septal defects. Although only a few case reports have described an association between TBX20 and DCM/left ventricular non-compaction (LVNC), there are no case-control studies available, and TBX20 is still considered a gene with limited evidence for these phenotypes. Objectives This study sought to investigate the relationship between truncating variants in TBX20 (TBX20tv) and the development of DCM and LVNC. Methods TBX20 was sequenced using massive parallel sequencing in 7,463 unrelated probands with DCM/LVNC and 22,773 probands with other diagnoses (e.g., hypertrophic or arrhythmogenic cardiomyopathy, channelopathies, or aortic diseases) as internal controls. It was tested for enrichment and cosegregation of TBX20tv in DCM/LVNC, and clinical characteristics and outcomes in carriers were analyzed. Results Twenty-four probands with 22 TBX20tv were identified. Variant frequencies were significantly higher in patients with DCM/LVNC (24/7,463; 0.29%) than in internal controls (2/22,773; 0.008%) or controls from the gnomAD database (4/124,098; 0.003%), with an OR of 70.18 (CI95%: 9.48 to 519.8; p &amp;lt;0.0001) and 95.61 (CI95%: 33.06-276.55; p &amp;lt;0.0001), respectively. Cosegregation was studied in 21 families, identifying 57 carriers, of whom 43 (75.4%) had cardiac involvement. A combined LODs score of 4.41 was obtained, which is indicative of very strong segregation. Regarding clinical characteristics, the mean age at diagnosis was 37 years old, and 50% of carriers were female. Forty-six percent developed left-ventricular dysfunction, which was moderate to severe in half of the cases. Three carriers received a heart transplant, and another carrier died due to heart failure. Congenital heart defects were present in 16 patients (28.1%). Valvular involvement was the most frequent congenital abnormality (5 cases had bicuspid aortic valve, and another 5 had mitral valve defects), followed by heart septal defects (3 atrial and 3 ventricular); coronary anomalies (2) and aortic coarctation (2) were also detected. In some patients, these defects presented as complex congenital heart disease. Conclusions TBX20tv are associated with the development of dilated and non-compaction cardiomyopathy, and the presence of congenital heart defects is also common. Although some carriers, particularly younger ones, may not present the phenotype, nearly half of them experience ventricular dysfunction, and significant cardiac events, such as cardiac death or transplantation, are not uncommon. Therefore, the TBX20 gene should be routinely included in genetic testing panels for DCM and LVNC.

A genetic polymorphism on chromosome 4q25 (rs17570669_T) may predict atrial fibrillation recurrence after successful electrical cardioversion

Abstract Background Direct current electrical cardioversion (DCCV), is an effective treatment method in patients with symptomatic persistent atrial fibrillation (AF). However, AF recurrence may occur following successful DCCV in nearly half of the patients. There is not enough data investigating the association between single nucleotide polymorphisms (SNP) and AF recurrence after DCCV. Purpose We aimed to investigate whether 11 SNPs previously associated with AF (rs2200733, rs10033464, rs6838973, rs3853445 and rs17570669 SNPs in PITX2 gene; rs2106261 SNP in ZFHX3 gene; rs751141 SNP on chromosome 8q21; rs3807989 SNP in CAV1 gene; rs10570248 SNP in TBX5 gene; rs1800469 SNP in TGF-1 gene; and rs6795970 SNP in SCN10A gene) were predictive for recurrence after successful DCCV in patients with persistent AF in Turkish society. Methods We included 75 patients with sinus rhythm after direct current electrical cardioversion (DCCV). Baseline clinical features and 11 AF-related SNPs were compared between patients with and without AF recurrence during the follow-up. The association between SNPs and AF recurrence was evaluated with the additive model (wild type vs heterozygous variant vs homozygous variant), the dominant model (wild type/heterozygous vs homozygous variant), and the recessive model (wild type vs heterozygous variant/homozygous variant). Results The mean age of the patients was 61.9 ± 11.5 years. At a mean follow-up of 17.0 (11.0-25.0) months, 38 patients (50.7%) developed AF recurrence. The frequency of the female gender was higher (55.3% vs. 32.4%), AF duration before DCCV was longer [9.2 (5.5-11.6) vs 5.0 (2.7-11.0) months], and left atrial volume index before DCCV was higher (43.6 ± 8.8 ml/m2 vs. 38.2 ± 12.9 ml/m2) in patients who developed AF recurrence than those without it (p=0.046, 0.029 and 0.036, respectively) (Figure 1a). In the additive model, a SNP at the PITX2 gene (rs17570669_T: OR 9.00, 95% CI 1.28-63.02, p=0.027) and a SNP at the ZFHX3 gene (rs2106261_T: OR 8.96, 95% CI 1.03-77.66, p=0.047) were significantly associated with AF recurrence. Female gender (HR: 1.99, 95% CI: 1.05-3.79, p=0.035) and the rs17570669_T SNP (HR: 4.16, 95% CI: 1.22-14.11, p=0.022) were predictors for AF recurrence in univariate analysis. A multivariate Cox regression analysis showed that the rs17570669_T SNP was an independent predictor of AF recurrence following successful DCCV in the additive model (HR: 3.59, 95% CI: 1.05-12.21, p=0.04) (Figure 1b). A Kaplan-Meier curve showed that AF-free survival was significantly lower in patients who had rs17570669_T SNP in the additive model (Figure 2). Conclusion A SNP at the PITX2 locus (rs17570669_T) may predict AF recurrence after successful DCCV in patients with persistent AF in Turkish society. Such individuals may be closely monitored for the development of AF recurrence after DCCV. In addition, reversible risk factors associated with AF recurrence may be more tightly controlled in such patients.Baseline features and Cox analysisKaplan-Meier curve

Tbx4 and Tbx5 gene expression associated with appendage development and its relationship with the absence of the pelvic fin in Pampus argenteus

Tbx4 and Tbx5 gene expression associated with appendage development and its relationship with the absence of the pelvic fin in Pampus argenteus

SAT625 The EGF-TBX19-EGFR Positive Feedback Loop Regulates The Expression Of The CD44v9/SLC7A11 Antioxidant System Within Corticotroph Pituitary Neuroendocrine Tumors

Abstract Disclosure: J. Chakrabarti: None. J. Eschbacher: None. K. Yuen: None. A.S. Little: None. Y. Zavros: None. Background: Stereotactic radiosurgery is a therapeutic modality considered in the adjuvant setting of patients with failed transsphenoidal surgery or recurrence of corticotroph pituitary neuroendocrine tumors (PitNETs), with variable biological remission rates ranging between 17% and 87%. Generated by alternative mRNA splicing (CD44v), CD44v9 is expressed in cancer stem cells and promotes resistance to reactive oxygen species (ROS) through the stabilization of the SLC7A11 (xCT) cystine glutamate transporter, but the role of this antioxidant system in PitNETs is unknown. TBX19 belongs to the T subfamily of TBX genes and is known to promote cancer cell metastasis. TBX19 is expressed within the pituitary gland and acts as a component of the proopiomelanocortin (POMC) gene activation program that works as a transcriptional activator. Epidermal Growth Factor Receptor (EGFR) via binding to its ligand Epidermal Growth Factor (EGF) signals to upregulate TBX19 expression via the ERK/NF-κB pathway. Within the pituitary, EGFR and its downstream pathway components (AKT, mTORC) are significantly increased in corticotroph PitNETs are associated with elevated ACTH secretion. Hypothesis: EGF/EGFR induces an EGF-TBX19-EGFR positive feedback loop that subsequently leads to the expression of the CD44v9/SLC7A11 antioxidant system within radiation-therapy resistant SOX2+ corticotroph PitNET cells. Methods: Human PitNET tissue was harvested during transsphenoidal pituitary surgery from CD patients to generate organoids (PitNETorg). Patient hPitNETsorg were pretreated with either Vandetanib (Vand), Rapamycin (Rapa, mTOR inhibitor), Erastin (xCT inhibitor), Mifepristone (Mife, glucocorticoid inhibitor) or Cabergoline (Caber, D2 receptor inhibitor) prior to 0, 4, 8 and 16Gy radiation doses. Functional analyses will be performed by spectral flow cytometry (Cytek™ Aurora), hormone secretion and high content confocal microscopy. Results: Decreased expression of CD44v9 and xCT correlated with increased apoptosis in hPitNETorg cultures in response to Vand, Rapa, and Erastin when compared to Veh, Mife and Caber pretreatments at an optimal radiation dose of 8Gy. Pretreatment of hPitNETorg with Rapa resulted in decreased expression CD44v9, a response mediated by of HIF-1α. Inhibition of TBX19 using a MEK inhibitor resulted in decreased expression of EGFR and downstream signaling components AKT and mTORC that correlated with decreased ACTH hPitNETorg secretion. Conclusions: The EGF-TBX19-EGFR positive feedback loop regulates CD44v9/xCT resistance to radiation therapy. Therefore, pretreatment of CD patients with drugs targeting the CD44v9/xCT antioxidant system may increase the efficacy, shorten latency time to remission, and decrease toxicity of stereotactic radiosurgery for the treatment of residual or recurrent functional corticotroph PitNETs. Presentation: Saturday, June 17, 2023

Specific genetic aberrations of parathyroid in Chinese patients with tertiary hyperparathyroidism using whole-exome sequencing.

Tertiary hyperparathyroidism (THPT) is a peculiar subtype of hyperparathyroidism that usually develops from chronic kidney disease (CKD) and persists even after kidney transplantation. Unlike its precursor, secondary hyperparathyroidism (SHPT), THPT is characterized by uncontrolled high levels of calcium in the blood, which suggests the monoclonal or oligoclonal proliferation of parathyroid cells. However, the molecular abnormalities leading to THPT have not yet been fully understood. In this study, we analyzed DNA samples from hyperplastic parathyroid and corresponding blood cells of 11 patients with THPT using whole-exome sequencing (WES). We identified somatic single nucleotide variants (SNV) and insertions or deletions variants (INDEL) and performed driver mutation analysis, KEGG pathway, and GO functional enrichment analysis. To confirm the impact of selected driver mutated genes, we also tested their expression level in these samples using qRT-PCR. Following quality control and mutation filtering, we identified 17,401 mutations, comprising 6690 missense variants, 3078 frameshift variants, 2005 stop-gained variants, and 1630 synonymous variants. Copy number variants (CNV) analysis showed that chromosome 22 copy number deletion was frequently observed in 6 samples. Driver mutation analysis identified 179 statistically significant mutated genes, including recurrent missense mutations on TBX20, ATAD5, ZNF669, and NOX3 genes in 3 different patients. KEGG pathway analysis revealed two enriched pathways: non-homologous end-joining and cell cycle, with a sole gene, PRKDC, involved. GO analysis demonstrated significant enrichment of various cellular components and cytobiological processes associated with four genes, including GO items of positive regulation of developmental growth, protein ubiquitination, and positive regulation of the apoptotic process. Compared to blood samples, THPT samples exhibited lower expression levels of PRKDC, TBX20, ATAD5, and NOX3 genes. THPT samples with exon mutations had relatively lower expression levels of PRKDC, TBX20, and NOX3 genes compared to those without mutations, although the difference was not statistically significant. This study provides a comprehensive landscape of the genetic characteristics of hyperplastic parathyroids in THPT, highlighting the involvement of multiple genes and pathways in the development and progression of this disease. The dominant mutations identified in our study depicted new insights into the pathogenesis and molecular characteristics of THPT.

Recurrent human 16p11.2 microdeletions in type I Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome patients in Chinese Han population.

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a severe congenital malformation of the female genital tract, is a highly heterogeneous disease which has no clear etiology. Previous studies have suggested that copy number variations (CNVs) and single-gene mutations might contribute to the development of MRKH syndrome. In particular, deletions in 16p11.2, which are suggested to be involved in several congenital diseases, have been reported in Chinese type II MRKH patients and European MRKH patients. However, few CNVs including 16p11.2 microdeletions were identified in Chinese type I MRKH cases although it accounted for the majority of MRKH patients in China. Thus, we conducted a retrospective study to identify whether CNVs at human chromosome 16p11.2 are risk factors of type I MRKH syndrome in the Chinese Han population. We recruited 143 patients diagnosed with type I MRKH between 2012 and 2014. Five hundred unrelated Chinese without congenital malformation were enrolled in control group, consisting of 197 from the 1000 Genomes Project and 303 from Fudan University. Quantitative PCR, array comparative genomic hybridization, and sanger sequencing were conducted to screen and verify candidate variant. Our study identified recurrent 16p11.2 microdeletions of approximately 600 kb in two out of the 143 type I MRKH syndrome patients using high-density array-based comparative genomic hybridization (aCGH), while no 16p11.2 deletion was found in the control group. We did not find any mutations in TBX6 gene in our samples. The results of the study identify 16p11.2 deletion in Chinese MRKH I patients for the first time, as well as support the contention that 16p11.2 microdeletions are associated with MRKH syndrome in both types across populations. It is suggested that 16p11.2 microdeletions should be included in molecular diagnosis and genetic counseling of female reproductive tract disorders.

Discovery of TBX20 as a Novel Gene Underlying Atrial Fibrillation.

Atrial fibrillation (AF), the most prevalent type of sustained cardiac dysrhythmia globally, confers strikingly enhanced risks for cognitive dysfunction, stroke, chronic cardiac failure, and sudden cardiovascular demise. Aggregating studies underscore the crucial roles of inherited determinants in the occurrence and perpetuation of AF. However, due to conspicuous genetic heterogeneity, the inherited defects accounting for AF remain largely indefinite. Here, via whole-genome genotyping with genetic markers and a linkage assay in a family suffering from AF, a new AF-causative locus was located at human chromosome 7p14.2-p14.3, a ~4.89 cM (~4.43-Mb) interval between the markers D7S526 and D7S2250. An exome-wide sequencing assay unveiled that, at the defined locus, the mutation in the TBX20 gene, NM_001077653.2: c.695A>G; p.(His232Arg), was solely co-segregated with AF in the family. Additionally, a Sanger sequencing assay of TBX20 in another family suffering from AF uncovered a novel mutation, NM_001077653.2: c.862G>C; p.(Asp288His). Neither of the two mutations were observed in 600 unrelated control individuals. Functional investigations demonstrated that the two mutations both significantly reduced the transactivation of the target gene KCNH2 (a well-established AF-causing gene) and the ability to bind the promoter of KCNH2, while they had no effect on the nuclear distribution of TBX20. Conclusively, these findings reveal a new AF-causative locus at human chromosome 7p14.2-p14.3 and strongly indicate TBX20 as a novel AF-predisposing gene, shedding light on the mechanism underlying AF and suggesting clinical significance for the allele-specific treatment of AF patients.