PRDM3/16 regulate chromatin accessibility required for NKX2-1 mediated alveolar epithelial differentiation and function.

While the critical role of NKX2-1 and its transcriptional targets in lung morphogenesis and pulmonary epithelial cell differentiation is increasingly known, mechanisms by which chromatin accessibility alters the epigenetic landscape and how NKX2-1 interacts with other co-activators required for alveolar epithelial cell differentiation and function are not well understood. Combined deletion of the histone methyl transferases Prdm3 and Prdm16 in early lung endoderm causes perinatal lethality due to respiratory failure from loss of AT2 cells and the accumulation of partially differentiated AT1 cells. Combination of single-cell RNA-seq, bulk ATAC-seq, and CUT&RUN data demonstrate that PRDM3 and PRDM16 regulate chromatin accessibility at NKX2-1 transcriptional targets critical for perinatal AT2 cell differentiation and surfactant homeostasis. Lineage specific deletion of PRDM3/16 in AT2 cells leads to lineage infidelity, with PRDM3/16 null cells acquiring partial AT1 fate. Together, these data demonstrate that NKX2-1-dependent regulation of alveolar epithelial cell differentiation is mediated by epigenomic modulation via PRDM3/16.

[Analysis of clinical characteristics and variant of NKX2-1 gene in a Chinese boy with Brain-Lung-Thyroid syndrome].

OBJECTIVE: To carry out clinical and genetic analysis for a child featuring Brain-Lung-Thyroid syndrome (BLTS). METHODS: A child who had presented at the Children's Hospital Affiliated to Shandong University on May 27, 2022 was selected as the study subject. Clinical data was collected. Trio-whole exome sequencing (Trio-WES) was carried out for the child and his parents, and candidate variant was verified by Sanger sequencing and bioinformatic analysis. The child was given individualized treatment following the diagnosis. RESULTS: The child, a two-year-and-seven-month-old boy, had presented with global developmental delay, ataxia and hypothyroidism. WES revealed that he has harbored a heterozygous c.674C>T variant of the NKX2-1 gene, based on which he was diagnosed with BLTS. CT scan revealed interstitial and parenchymal inflammation in his lungs, which was reduced by budesonide aerosol inhalation. CONCLUSION: Discovery of the novel c.674C>T variant has enriched the mutational spectrum of the NKX2-1 gene. Budesonide aerosol may be used to treat lung inflammation associated with BLTS.

Systematic review of thyroid function in NKX2-1-related disorders: Screening and diagnosis.

BACKGROUND: NKX2-1-related disorders (NKX2-1-RD) are rare conditions affecting lung, thyroid, and brain development, primarily caused by pathogenic variants or deletions in the NKX2-1 gene. Congenital hypothyroidism (CH) is a common endocrine manifestation, leading to irreversible intellectual disability if left untreated. OBJECTIVES: The aim was to evaluate the current evidence for the use of screening and diagnostic techniques for endocrine alterations in patients with NKX2-1-RD. METHODS: This systematic review was reported following the PRISMA guidelines. Two separate research questions in PICO format were addressed to cover initial screening and diagnosis procedures for endocrine diseases in patients with NKX2-1-RD. Eligibility criteria focused on patients with genetic confirmation of the disease and hypothyroidism. Various databases were searched, and data were extracted and assessed independently by two reviewers. RESULTS: Out of 1012 potentially relevant studies, 46 were included, for a total of 113 patients. CH was the most frequent endocrine alteration (45% of patients). Neonatal screening was reported in only 21% of patients based on blood TSH measurements. TSH thresholds varied widely across studies, making hypothyroidism detection ranges difficult to establish. Diagnostic tests using serum TSH were used to diagnose hypothyroidism or confirm its presence. 35% of patients were diagnosed at neonatal age, and 42% at adult age. Other hormonal dysfunctions identified due to clinical signs, such as anterior pituitary deficiencies, were detected later in life. Thyroid scintigraphy and ultrasonography allowed for the description of the thyroid gland in 30% of cases of hypothyroidism. Phenotypic variability was observed in individuals with the same variants, making genotype-phenotype correlations challenging. CONCLUSION: This review highlights the need for standardized protocols in endocrine screening for NKX2-1-RD, emphasizing the importance of consistent methodology and hormone threshold levels. Variability in NKX2-1 gene variants further complicates diagnostic efforts. Future research should concentrate on optimizing early screening protocols and diagnostic strategies.

Gastric-Type Expression Signature in Hepatocellular Carcinoma.

It is known that V-set and immunoglobulin domain containing 1 (VSIG1) is a cell-cell adhesion molecule that can serve as an indicator of better survival in patients with gastric cancer. Its interaction with cytoplasmic thyroid transcription factor 1 (TTF-1) has been hypothesized to characterize gastric-type HCC, but its clinical importance is far from understood. As VSIG1 has also been supposed to be involved in the epithelial-mesenchymal transition (EMT) phenomenon, we checked for the first time in the literature the supposed interaction between VSIG1, TTF-1, and Vimentin (VIM) in HCCs. Immunohistochemical (IHC) stains were performed on 217 paraffin-embedded tissue samples that included tumor cells and normal hepatocytes, which served as positive internal controls. VSIG1 positivity was seen in 113 cases (52.07%). In 71 out of 217 HCCs (32.71%), simultaneous positivity for VSIG1 and TTF-1 was seen, being more specific for G1/G2 carcinomas with a trabecular architecture and a longer OS (p = 0.004). A negative association with VIM was revealed (p < 0.0001). Scirrhous-type HCC proved negative for all three examined markers. The present paper validates the hypothesis of the existence of a gastric-type HCC, which shows a glandular-like architecture and is characterized by double positivity for VSIG1 and TTF-1, vimentin negativity, and a significant OS.

Insights from European Reference Network for rare neurological disorders study surveys on diagnosis, treatment, and management of NKX2-1-related disorders.

BACKGROUND: NKX2-1-related disorder (NKX2-1-RD) is a rare disease characterized by a triad of primary hypothyroidism, neonatal respiratory distress, and neurological features, including chorea. OBJECTIVE: This study aimed to identify discrepancies in the management of NKX2-1-RD among European Union (EU) specialists. METHODS: The ERN-RND Chorea & Huntington disease group designed a survey to conduct a cross-sectional multicenter study on the management of NKX2-1-RD. Descriptive analysis was performed, and total responses are presented for each item. RESULTS: The study involved 23 experts from 13 EU countries with experience in evaluating hyperkinetic patients with NKX2-1-RD: 11 were adult specialists, and 12 were pediatric specialists. NKX2-1-RD diagnosis was made at different ages, with the most common initial symptoms being hypotonia and/or motor developmental delay (reported by 11 experts) and chorea (reported by 8 experts). Chorea involved various body parts and showed improvement as reported by 9 experts, stabilization by 12 experts, and worsening by 2 experts with age. The pharmacological treatment of chorea varied widely among the experts. Misdiagnosis was reported by 14 experts. NKX2-1 pathogenic variants or deletions were confirmed in >75 % of patients (reported by 12 experts). Pulmonary and endocrinology evaluations were requested by 7 and 12 experts, respectively. The management of psychiatric comorbidities also varied among the different experts. CONCLUSIONS: This study highlights the need for a clinical practice guideline for the management of NKX2-1-RD to ensure that patients across the EU receive consistent and appropriate care. Such a guideline would benefit both doctors and healthcare practitioners.

Differential diagnosis of Huntington's disease- neurological aspects of NKX2-1-related disorders.

Benign hereditary chorea (BHC) is an inherited neurological disorder consisting of childhood-onset, nonprogressive chorea, generally without any other manifestations. In most reported cases, the inheritance of BHC is autosomal dominant but both incomplete penetrance and variable expressivity are observed and can be caused by NKX2-1 mutations. The spectrum contains choreoathetosis, congenital hypothyroidism, and neonatal respiratory distress syndrome. The neurological symptoms can be misdiagnosed as Huntington's disease (HD). The two Polish families were diagnosed with NKX2-1 gene mutations and a literature review concerning the NKX2-1-related disorders was conducted. All family members were examined by experienced movement disorders specialists. PubMed database was searched to obtain previously described NKX2-1 cases. Whole exome sequencing (WES) was performed in one proband (Family A) and direct NKX2-1 sequencing in the second (Family B). Two Polish families were diagnosed with NKX2-1 gene mutations (p.Trp208Leu and p.Cys117Alafs*8). In one family, the co-occurrence of HD was reported. Forty-nine publications were included in the literature review and symptoms of 195 patients with confirmed NKX2-1 mutation were analyzed. The most common symptoms were chorea and choreiform movements, and delayed motor milestones. The NKX2-1 mutation should always be considered as a potential diagnosis in families with chorea, even with a family history of HD. Lack of chorea does not exclude the NKX2-1-related disorders.

Significance of NKX2-1 as a biomarker for clinical prognosis, immune infiltration, and drug therapy in lung squamous cell carcinoma.

Background: This study was performed to determine the biological processes in which NKX2-1 is involved and thus its role in the development of lung squamous cell carcinoma (LUSC) toward improving the prognosis and treatment of LUSC. Methods: Raw RNA sequencing (RNA-seq) data of LUSC from The Cancer Genome Atlas (TCGA) were used in bioinformatics analysis to characterize NKX2-1 expression levels in tumor and normal tissues. Survival analysis of Kaplan-Meier curve, the time-dependent receiver operating characteristic (ROC) curve, and a nomogram were used to analyze the prognosis value of NKX2-1 for LUSC in terms of overall survival (OS) and progression-free survival (PFS). Then, differentially expressed genes (DEGs) were identified, and Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA) were used to clarify the biological mechanisms potentially involved in the development of LUSC. Moreover, the correlation between the NKX2-1 expression level and tumor mutation burden (TMB), tumor microenvironment (TME), and immune cell infiltration revealed that NKX2-1 participates in the development of LUSC. Finally, we studied the effects of NKX2-1 on drug therapy. To validate the protein and gene expression levels of NKX2-1 in LUSC, we employed immunohistochemistry(IHC) datasets, The Gene Expression Omnibus (GEO) database, and qRT-PCR analysis. Results: NKX2-1 expression levels were significantly lower in LUSC than in normal lung tissue. It significantly differed in gender, stage and N classification. The survival analysis revealed that high expression of NKX2-1 had shorter OS and PFS in LUSC. The multivariate Cox regression hazard model showed the NKX2-1 expression as an independent prognostic factor. Then, the nomogram predicted LUSC prognosis. There are 51 upregulated DEGs and 49 downregulated DEGs in the NKX2-1 high-level groups. GO, KEGG and GSEA analysis revealed that DEGs were enriched in cell cycle and DNA replication.The TME results show that NKX2-1 expression was positively associated with mast cells resting, neutrophils, monocytes, T cells CD4 memory resting, and M2 macrophages but negatively associated with M1 macrophages. The TMB correlated negatively with NKX2-1 expression. The pharmacotherapy had great sensitivity in the NKX2-1 low-level group, the immunotherapy is no significant difference in the NKX2-1 low-level and high-level groups. The analysis of GEO data demonstrated concurrence with TCGA results. IHC revealed NKX2-1 protein expression in tumor tissues of both LUAD and LUSC. Meanwhile qRT-PCR analysis indicated a significantly lower NKX2-1 expression level in LUSC compared to LUAD. These qRT-PCR findings were consistent with co-expression analysis of NKX2-1. Conclusion: We conclude that NKX2-1 is a potential biomarker for prognosis and treatment LUSC. A new insights of NKX2-1 in LUSC is still needed further research.

A Novel Missense Variant in the NKX2-1 Homeodomain Prevents Transcriptional Rescue by TAZ.

Background: Brain-lung-thyroid syndrome (BLTS) is caused by NKX2-1 haploinsufficiency, resulting in chorea/choreoathetosis, respiratory problems, and hypothyroidism. Genes interacting with NKX2-1 mutants influence its phenotypic variability. We report a novel NKX2-1 missense variant and the modifier function of TAZ/WWTR1 in BLTS. Methods: A child with BLTS underwent next-generation sequencing panel testing for thyroid disorders. His family was genotyped for NKX2-1 variants and screened for germline mosaicism. Mutant NKX2-1 was generated, and transactivation assays were performed on three NKX2-1 target gene promoters. DNA binding capacity and protein-protein interaction were analyzed. Results: The patient had severe BLTS and carried a novel missense variant c.632A>G (p.N211S) in NKX2-1, which failed to bind to specific DNA promoters, reducing their transactivation. TAZ cotransfection did not significantly increase transcription of these genes, although the variant retained its ability to bind to TAZ. Conclusions: We identify a novel pathogenic NKX2-1 variant that causes severe BLTS and is inherited through germline mosaicism. The mutant lacks DNA-binding capacity, impairing transactivation and suggesting that NKX2-1 binding to DNA is essential for TAZ-mediated transcriptional rescue.

CEBPA restricts alveolar type 2 cell plasticity during development and injury-repair.

Cell plasticity theoretically extends to all possible cell types, but naturally decreases as cells differentiate, whereas injury-repair re-engages the developmental plasticity. Here we show that the lung alveolar type 2 (AT2)-specific transcription factor (TF), CEBPA, restricts AT2 cell plasticity in the mouse lung. AT2 cells undergo transcriptional and epigenetic maturation postnatally. Without CEBPA, both neonatal and mature AT2 cells reduce the AT2 program, but only the former reactivate the SOX9 progenitor program. Sendai virus infection bestows mature AT2 cells with neonatal plasticity where Cebpa mutant, but not wild type, AT2 cells express SOX9, as well as more readily proliferate and form KRT8/CLDN4+ transitional cells. CEBPA promotes the AT2 program by recruiting the lung lineage TF NKX2-1. The temporal change in CEBPA-dependent plasticity reflects AT2 cell developmental history. The ontogeny of AT2 cell plasticity and its transcriptional and epigenetic mechanisms have implications in lung regeneration and cancer.

High risk of lung cancer in surfactant-related gene variant carriers.

BACKGROUND: Several rare surfactant-related gene (SRG) variants associated with interstitial lung disease are suspected to be associated with lung cancer, but data are missing. We aimed to study the epidemiology and phenotype of lung cancer in an international cohort of SRG variant carriers. METHODS: We conducted a cross-sectional study of all adults with SRG variants in the OrphaLung network and compared lung cancer risk with telomere-related gene (TRG) variant carriers. RESULTS: We identified 99 SRG adult variant carriers (SFTPA1 (n=18), SFTPA2 (n=31), SFTPC (n=24), ABCA3 (n=14) and NKX2-1 (n=12)), including 20 (20.2%) with lung cancer (SFTPA1 (n=7), SFTPA2 (n=8), SFTPC (n=3), NKX2-1 (n=2) and ABCA3 (n=0)). Among SRG variant carriers, the odds of lung cancer was associated with age (OR 1.04, 95% CI 1.01-1.08), smoking (OR 20.7, 95% CI 6.60-76.2) and SFTPA1/SFTPA2 variants (OR 3.97, 95% CI 1.39-13.2). Adenocarcinoma was the only histological type reported, with programmed death ligand-1 expression ≥1% in tumour cells in three samples. Cancer staging was localised (I/II) in eight (40%) individuals, locally advanced (III) in two (10%) and metastatic (IV) in 10 (50%). We found no somatic variant eligible for targeted therapy. Seven cancers were surgically removed, 10 received systemic therapy, and three received the best supportive care according to their stage and performance status. The median overall survival was 24 months, with stage I/II cancers showing better survival. We identified 233 TRG variant carriers. The comparative risk (subdistribution hazard ratio) for lung cancer in SRG patients versus TRG patients was 18.1 (95% CI 7.1-44.7). CONCLUSIONS: The high risk of lung cancer among SRG variant carriers suggests specific screening and diagnostic and therapeutic challenges. The benefit of regular computed tomography scan follow-up should be evaluated.

A case report of loss of thyroid transcription factor 1 expression in lung adenocarcinoma EBUS FNA.

We present a case report of a 76-year-old male with a histologically confirmed KRAS mutated, thyroid transcription factor 1 (TTF1) positive, grade 1, mucinous adenocarcinoma with cytologically difficult to interpret lymph node metastasis showing loss of TTF1 expression and overlapping features with goblet cell hyperplasia. The case highlights the importance of molecular testing in aiding diagnosis and guiding treatment of non-small cell lung carcinomas (NSCLC).

CRISPR-Cas9 Genome Editing Allows Generation of the Mouse Lung in a Rat.

Rationale: Recent efforts in bioengineering and embryonic stem cell (ESC) technology allowed the generation of ESC-derived mouse lung tissues in transgenic mice that were missing critical morphogenetic genes. Epithelial cell lineages were efficiently generated from ESC, but other cell types were mosaic. A complete contribution of donor ESCs to lung tissue has never been achieved. The mouse lung has never been generated in a rat. Objective: We sought to generate the mouse lung in a rat. Methods: Clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 genome editing was used to disrupt the Nkx2-1 gene in rat one-cell zygotes. Interspecies mouse-rat chimeras were produced by injection of wild-type mouse ESCs into Nkx2-1-deficient rat embryos with lung agenesis. The contribution of mouse ESCs to the lung tissue was examined by immunostaining, flow cytometry, and single-cell RNA sequencing. Measurements and Main Results: Peripheral pulmonary and thyroid tissues were absent in rat embryos after CRISPR-Cas9-mediated disruption of the Nkx2-1 gene. Complementation of rat Nkx2-1-/- blastocysts with mouse ESCs restored pulmonary and thyroid structures in mouse-rat chimeras, leading to a near-99% contribution of ESCs to all respiratory cell lineages. Epithelial, endothelial, hematopoietic, and stromal cells in ESC-derived lungs were highly differentiated and exhibited lineage-specific gene signatures similar to those of respiratory cells from the normal mouse lung. Analysis of receptor-ligand interactions revealed normal signaling networks between mouse ESC-derived respiratory cells differentiated in a rat. Conclusions: A combination of CRISPR-Cas9 genome editing and blastocyst complementation was used to produce mouse lungs in rats, making an important step toward future generations of human lungs using large animals as "bioreactors."

NKX2-1 gene is targeted by H19 lncRNA and is found to be overexpressed in benign nodular goiter tissues.

OBJECTIVE: Nodular goiter may increase the risk of thyroid cancer, but the genetic factors contributing to nodular goiter are not well understood. There is an overexpression of H19 lncRNA in goiter tissue and its target remains unknown. In this study, we attempted to identify a new target for H19 in the context of goiter development. METHODS: Using interaction energy calculations, the interaction between NKX2-1 mRNA and H19 lncRNA was examined. Putative microRNAs were found at the H19 lncRNA target site with the highest affinity for NKX2-1. RNAseq data was analyzed to determine the tissue specificity of gene expression. Samples were taken from 18 goiter and 18 normal tissues during thyroidectomy. The expression of NKX2-1 was determined by RT-qPCR using specific primers. RESULTS: The interaction between NKX2-1 and H19 was characterized by six local base-pairing connections, with a maximum energy of -20.56 kcal/moL. Specifically, the sequence that displayed the highest affinity for binding with H19 overlapped with the binding site of has-miR-1827 to NKX2-1. It was found that NKX2-1 is exclusively co-expressed with H19 in normal thyroid tissue. As compared to adjacent normal tissues, nodular goiter tissues have a significant overexpression of NKX2-1 (relative expression = 1.195, p =  0.038). CONCLUSION: NKX2-1 has been identified as the putative target of H19 lncRNA, which is overexpressed in nodular goiter tissues significantly.

TTF-1 status in early-stage lung adenocarcinoma is an independent predictor of relapse and survival superior to tumor grading.

OBJECTIVES: Thyroid transcription factor 1 (TTF-1) is a well-established independent prognostic factor in lung adenocarcinoma (LUAD), irrespective of stage. This study aims to determine if TTF-1's prognostic impact is solely based on histomorphological differentiation (tumor grading) or if it independently relates to a biologically more aggressive phenotype. We analyzed a large bi-centric LUAD cohort to accurately assess TTF-1's prognostic value in relation to tumor grade. PATIENTS AND METHODS: We studied 447 patients with resected LUAD from major German lung cancer centers (Berlin and Cologne), correlating TTF-1 status and grading with clinical, pathologic, and molecular data, alongside patient outcomes. TTF-1's impact was evaluated through univariate and multivariate Cox regression. Causal graph analysis was used to identify and account for potential confounders, improving the statistical estimation of TTF-1's predictive power for clinical outcomes. RESULTS: Univariate analysis revealed TTF-1 positivity associated with significantly longer disease-free survival (DFS) (median log HR -0.83; p = 0.018). Higher tumor grade showed a non-significant association with shorter DFS (median log HR 0.30; p = 0,62 for G1 to G2 and 0.68; p = 0,34 for G2 to G3). In multivariate analysis, TTF-1 positivity resulted in a significantly longer DFS (median log HR -0.65; p = 0.05) independent of all other parameters, including grading. Adjusting for potential confounders as indicated by the causal graph confirmed the superiority of TTF-1 over tumor grading in prognostics power. CONCLUSIONS: TTF-1 status predicts relapse and survival in LUAD independently of tumor grading. The prognostic power of tumor grading is limited to TTF-1-positive patients, and the effect size of TTF-1 surpasses that of tumor grading. We recommend including TTF1 status as a prognostic factor in the diagnostic guidelines of LUAD.

Regulatory effect of NK homeobox 1 (NKX2.1) on melanocortin 4 receptor (Mc4r) promoter in Mandarin fish.

The melanocortin 4 receptor (MC4R) is a G protein-coupled transporter that mediates the regulation of thyroid hormones and leptin on energy balance and food intake. However, the mechanisms of transcriptional regulation of Mc4r by thyroid hormone and leptin in fish have been rarely reported. The messenger RNA expression of Mc4r gene was significantly higher in brain than those in other tissues of mandarin fish. We analyzed the structure and function of a 2029 bp sequence of Mc4r promoter. Meanwhile, overexpression of NKX2.1 and incubation with leptin significantly increased Mc4r promoter activity, but triiodothyronine showed the opposite effect. In addition, mutations in the NKX2.1 binding site abolished not only the activation of Mc4r promoter activity by leptin but also the inhibitory effect of thyroid hormones on Mc4r promoter activity. In summary, these results suggested that thyroid hormones and leptin might regulate the transcriptional expression of Mc4r through NKX2.1.

Expression landscapes in non-small cell lung cancer shaped by the thyroid transcription factor 1.

TTF-1-expressing non-small cell lung cancer (NSCLC) is one of the most prevalent lung cancer types worldwide. However, theparadoxical activity of TTF-1 in both lung carcinogenesis and tumor suppression is believed to be context-dependentwhich calls for a deeper understanding about the pathological expression of TTF-1. In addition, the expression circuitry of TTF-1-target genes in NSCLC has not been well examined which necessitates to revisit the involvement of TTF-1- in a multitude of oncologic pathways. We used RNA-seq and clinical data of patients from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx), including ChIP-seq data from different NSCLC cell lines, and mapped the proteome of NSCLC tumor. Our analysis showed significant variability in TTF-1 expression among NSCLC,and further clarified that this variability is orchestrated at the transcriptional level. We also found that high TTF-1 expression could negatively influence the survival outcomes of stage 1 LUAD which may be attributed to growth factor receptor-driven activation of mitogenic and angiogenic pathways. Mechanistically, TTF-1 may also control the genes associated with pathways involved in acquired TKI drug resistance or response to immune checkpoint inhibitors. Lastly, proteome-based biomarker discovery in stage 1 LUAD showed that TTF-1 positivity is potentially associated with the upregulation of several oncogenes which includes interferon proteins, MUC1, STAT3, and EIF2AK2. Collectively, this study highlights the potential involvement of TTF-1 in cell proliferation, immune evasion, and angiogenesis in early-stage NSCLC.

Transcriptome analysis reveals the essential role of NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) in gastric adenocarcinoma of fundic-gland type.

BACKGROUND: Gastric adenocarcinoma of fundic-gland type (GA-FG) is a gastric malignancy with little relation to Helicobacter pylori. Clinical characteristics of GA-FG have been established, but molecular mechanisms leading to tumorigenesis have not yet been elucidated. METHODS: We subjected three GA-FG tumors-normal mucosa pairs to microarray analysis. Network analysis was performed for the top 30 up-regulated gene transcripts, followed by immunohistochemical staining to confirm the gene expression analysis results. AGS and NUGC4 cells were transfected with the gene-encoding NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) to evaluate transcriptional changes in its target genes. RESULTS: Comprehensive gene expression analysis identified 1410 up-regulated and 1395 down-regulated gene probes with ≥ two-fold difference in expression. Among the top 30 up-regulated genes in GA-FG, we identified transcription factor NKX2-1/TTF-1, a master regulator of lung/thyroid differentiation, together with surfactant protein B (SFTPB), SFTPC, and secretoglobin family 3A member 2(SCGB3A2), which are regulated by NKX2-1/TTF-1. Immunohistochemical analysis of 16 GA-FG specimens demonstrated significantly higher NKX2-1/TTF-1 and SFTPB levels, as compared to that in adjacent normal mucosa (P < 0.05), while SCGB3A2 levels did not differ (P = 0.341). Transduction of NKX2-1/TTF-1 into AGS and NUGC4 cells induced transactivation of SFTPB and SFTPC, indicating that NKX2-1/TTF-1 can function as normally in gastric cells as it can in the lung cells. CONCLUSIONS: Our first transcriptome analysis of GA-FG indicates significant expression of NKX2-1/TTF1 in GA-FG. Immunohistochemistry and cell biology show ectopic expression and normal transactivation ability of NKX2-1/TTF-1, suggesting that it plays an essential role in GA-FG development.

Development of a Lung Vacancy Mouse Model through CRISPR/Cas9-Mediated Deletion of Thyroid Transcription Factor 1 Exon 2.

A developmental niche vacancy in host embryos is necessary for stem cell complementation-based organ regeneration (SCOG). Thyroid transcription factor 1 (TTF-1) is a tissue-specific transcription factor that regulates the embryonic development and differentiation of the thyroid and, more importantly, lungs; thus, it has been considered as a master gene to knockout in order to develop a lung vacancy host. TTF-1 knockout mice were originally produced by inserting a stop codon in Exon 3 of the gene (E3stop) through embryonic stem cell-based homologous recombination. The main problems of utilizing E3stop host embryos for lung SCOG are that these animals all have a tracheoesophageal fistula (TEF), which cannot be corrected by donor stem cells, and most of them have monolateral sac-like lungs. To improve the mouse model towards achieving SCOG-based lung generation, in this project, we used the CRISPR/Cas9 tool to remove Exon 2 of the gene by zygote microinjection and successfully produced TTF-1 knockout (E2del) mice. Similar to E3stop, E2del mice are birth-lethal due to retarded lung development with sac-like lungs and only a rudimentary bronchial tree, increased basal cells but without alveolar type II cells and blood vessels, and abnormal thyroid development. Unlike E3stop, 57% of the E2del embryos presented type I tracheal agenesis (TA, a kind of human congenital malformation) with a shortened trachea and clear separations of the trachea and esophagus, while the remaining 43% had TEF. Furthermore, all the E2del mice had bilateral sac-like lungs. Both TA and bilateral sac-like lungs are preferred in SCOG. Our work presents a new strategy for producing SCOG host embryos that may be useful for lung regeneration.

Hypothalamic TTF-1 orchestrates the sensitivity of leptin.

OBJECTIVE: Thyroid transcription factor-1 (TTF-1), a homeodomain-containing transcription factor, is predominantly expressed in discrete areas of the hypothalamus, which acts as the central unit for the regulation of whole-body energy homeostasis. Current study designed to identify the roles of TTF-1 on the responsiveness of the hypothalamic circuit activity to circulating leptin and the development of obesity linked to the insensitivity of leptin. METHODS: We generated conditional knock-out mice by crossing TTF-1flox/flox mice with leptin receptor (ObRb)Cre or proopiomelanocortin (POMC)Cre transgenic mice to interrogate the contributions of TTF-1 in leptin signaling and activity. Changes of food intake, body weight and energy expenditure were evaluated in standard or high fat diet-treated transgenic mice by using an indirect calorimetry instrument. Molecular mechanism was elucidated with immunohistochemistry, immunoblotting, quantitative PCR, and promoter assays. RESULTS: The selective deletion of TTF-1 gene expression in cells expressing the ObRb or POMC enhanced the anorexigenic effects of leptin as well as the leptin-induced phosphorylation of STAT3. We further determined that TTF-1 inhibited the transcriptional activity of the ObRb gene. In line with these findings, the selective deletion of the TTF-1 gene in ObRb-positive cells led to protective effects against diet-induced obesity via the amelioration of leptin resistance. CONCLUSIONS: Collectively, these results suggest that hypothalamic TTF-1 participates in the development of obesity as a molecular component involved in the regulation of cellular leptin signaling and activity. Thus, TTF-1 may represent a therapeutic target for the treatment, prevention, and control of obesity.