Transcript Release Research Articles

The expression of polymerase I and transcript release factor in non-small cell lung cancer and mechanism research

Objective To explore the functions of PTRF in non-small cell lung cancer. Methods Two short hairpin RNA (shRNA) and one control shRNA were constructed. And then blank, control, shRNA-A and shRNA-B were transfected in A549 and mRNA and protein levels were detected using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Wound healing and invasion assays were done to detect the capability of migration and invasion in A549 cell lines. Results mRNA and protein levels of PTRF in cancer tissues were significantly lower than those in adjacent cancer tissues(P=0.003, P=0.016). mRNA levels of PTRF in shRNA-A and shRNA-B were lower than those in controls(P=0.009, P=0.012). Protein levels of PTRF in shRNA-A and shRNA-B were lower than those in controls(P=0.002, P=0.005). Higher levels of migration and invasion were observed in A549 cell lines after transfection with shRNA-A and shRNA-B(P=0.018, P=0.029 and P=0.024, P=0.038). Conclusion PTRF was decreased and promoted migration in lung cancer. Key words: Polymerase I and transcript release factor; Non-small cell lung cancer; Migration; Small interfering RNA

Negative elongation factor is essential for endometrial function.

Pausing of RNA polymerase II (Pol II) during early transcription, mediated by the negative elongation factor (NELF) complex, allows cells to coordinate and appropriately respond to signals by modulating the rate of transcriptional pause release. Promoter proximal enrichment of Pol II occurs at uterine genes relevant to reproductive biology; thus, we hypothesized that pausing might impact endometrial response by coordinating hormonal signals involved in establishing and maintaining pregnancy. We deleted the NELF-B subunit in the mouse uterus using PgrCre (NELF-B UtcKO). Resulting females were infertile. Uterine response to the initial decidual stimulus of NELF-B UtcKO was similar to that of control mice; however, subsequent full decidual response was not observed. Cultured NELF-B UtcKO stromal cells exhibited perturbances in extracellular matrix components and also expressed elevated levels of the decidual prolactin Prl8a2, as well as altered levels of transcripts encoding enzymes involved in prostaglandin synthesis and metabolism. Because endometrial stromal cell decidualization is also critical to human reproductive health and fertility, we used small interfering to suppress NELF-B or NELF-E subunits in cultured human endometrial stromal cells, which inhibited decidualization, as reflected by the impaired induction of decidual markers PRL and IGFBP1. Overall, our study indicates NELF-mediated pausing is essential to coordinate endometrial responses and that disruption impairs uterine decidual development during pregnancy.-Hewitt, S. C., Li, R., Adams, N., Winuthayanon, W., Hamilton, K. J., Donoghue, L. J., Lierz, S. L., Garcia, M., Lydon, J. P., DeMayo, F. J., Adelman, K., Korach, K. S. Negative elongation factor is essential for endometrial function.

Displacement of the transcription factor B reader domain during transcription initiation.

Transcription initiation by archaeal RNA polymerase (RNAP) and eukaryotic RNAP II requires the general transcription factor (TF) B/ IIB. Structural analyses of eukaryotic transcription initiation complexes locate the B-reader domain of TFIIB in close proximity to the active site of RNAP II. Here, we present the first crosslinking mapping data that describe the dynamic transitions of an archaeal TFB to provide evidence for structural rearrangements within the transcription complex during transition from initiation to early elongation phase of transcription. Using a highly specific UV-inducible crosslinking system based on the unnatural amino acid para-benzoyl-phenylalanine allowed us to analyze contacts of the Pyrococcus furiosus TFB B-reader domain with site-specific radiolabeled DNA templates in preinitiation and initially transcribing complexes. Crosslink reactions at different initiation steps demonstrate interactions of TFB with DNA at registers +6 to +14, and reduced contacts at +15, with structural transitions of the B-reader domain detected at register +10. Our data suggest that the B-reader domain of TFB interacts with nascent RNA at register +6 and +8 and it is displaced from the transcribed-strand during the transition from +9 to +10, followed by the collapse of the transcription bubble and release of TFB from register +15 onwards.

P-TEFb and Brd4: actors of the transcription pause release as therapeutical targets

Most cell physiology events are dictated by the integration of perceived signals and the elaboration by cells of adapted answers via the execution of proper transcriptional programs. In order to ensure an optimal control of these answers, many regulation mechanisms have been selected throughout the evolution, thus allowing to fine-tune transcript expression. The transcriptional pause and its release by P-TEFb (Positive Transcription Elongation Factor) have been evidenced two decades ago. Since then, the importance of such mechanisms has been highlighted by the association between alterations of this machinery and the appearance of diseases. P-TEFb and Brd4 have thus recently emerged as potential therapeutical targets for cancers and AIDS notably. In this review, we present a brief case history and an up-to-date synthesis of models for transcriptional pause release. We later discuss on the pathophysiological processes associated with this mechanism and clinical trials targeting Brd4 and P-TEFb.

NASP antagonize chromatin accessibility through maintaining histone H3K9me1 in hepatocellular carcinoma

The regulation of histone deposits mediated by multi-chaperone complexes under physiological conditions remains to be further investigated. Here, we studied the function of nuclear autoantigenic sperm protein (NASP) in the regulation of liver cancer. We found that NASP levels in liver tumors were generally higher than in normal liver tissues and NASP down-regulation inhibited liver cancer cells from forming tumors. We further analyzed cellular responses and epigenetic mechanisms of the histone H3-H4 shortage induced by NASP knockdown in liver cancer cells. The results showed that the major effects of NASP knockdown were globally enhanced chromatin accessibility, which facilitates transcription release, and failure of replication initiation. Furthermore, we demonstrated that NASP depletion led to a global decrease of histone H3K9me1 modification associated with newly H3 processing, which occurred directly at the promoters of up-regulated anti-tumor genes BACH2 and RunX1T1. This also resulted in a synergistic effect on enhanced apoptosis with Myc and p53 decreases. Overall, our work provides new insights into the roles of NASP in tumorigenesis and cancer prevention.

Characteristic findings of skeletal muscle MRI in caveolinopathies

Caveolinopathies, caused by CAV3 mutations, can include several phenotypes such as rippling muscle disease, limb-girdle muscular dystrophy type 1C, distal myopathy, familial hypertrophic cardiomyopathy, and idiopathic hyperCKemia. Here we present characteristic skeletal muscle imaging findings in four patients with genetically defined childhood-onset RMD caused by CAV3 mutations and in one patient with congenital generalized lipodystrophy type 4 with muscular dystrophy due to polymerase I and transcript release factor (PTRF) mutations, which may have caused secondary deficiency of caveolin-3. Muscle MRI revealed that the rectus femoris and semitendinosus muscles were most commonly affected in the rippling muscle disease patients. Peripheral changes in the rectus femoris were specific and observed even in one of the younger patients in this study. Furthermore, muscle involvement extended to the semitendinosus muscles, biceps femoris, and gracilis with disease progression or increase in its severity. Similar patterns of involvement were observed on reviewing skeletal muscle images of various previously reported phenotypes of caveolinopathy; interestingly, patients with secondary deficiency of caveolin due to PTRF mutations revealed the same pattern. Thus, primary caveolinopathies and secondary deficiency of caveolin demonstrated specific findings on skeletal muscle imaging, regardless of the broad phenotypic spectrum of these two conditions.

Dephosphorylated Polymerase I and Transcript Release Factor Prevents Allergic Asthma Exacerbations by Limiting IL-33 Release.

Asthma is a chronic inflammatory disease characterized by airway inflammation and airway hyperresponsiveness (AHR). IL-33 is considered as one of the most critical molecules in asthma pathogenesis. IL-33 is stored in nucleus and passively released during necrosis. But little is known about whether living cells can release IL-33 and how this process is regulated. We sought to investigate the role of polymerase I and transcript release factor (PTRF) in IL-33 release and asthma pathogenesis. Ovalbumin (OVA)-induced asthma model in PTRF+/- mice were employed to dissect the role of PTRF in vivo. Then, further in vitro experiments were carried out to unwind the potential mechanism involved. In OVA asthma model with challenge phase, PTRF+/- mice showed a greater airway hyper-reaction, with an intense airway inflammation and more eosinophils in bronchoalveolar lavage fluid (BALF). Consistently, more acute type 2 immune response in lung and a higher IL-33 level in BALF were found in PTRF+/- mice. In OVA asthma model without challenge phase, airway inflammation and local type 2 immune responses were comparable between control mice and PTRF+/- mice. Knockdown of PTRF in 16HBE led to a significantly increased level of IL-33 in cell culture supernatants in response to LPS or HDM. Immunoprecipitation assay clarified Y158 as the major phosphorylation site of PTRF, which was also critical for the interaction of IL-33 and PTRF. Overexpression of dephosphorylated mutant Y158F of PTRF sequestered IL-33 in nucleus together with PTRF and limited IL-33 extracellular secretion. Partial loss of PTRF led to a greater AHR and potent type 2 immune responses during challenge phase of asthma model, without influencing the sensitization phase. PTRF phosphorylation status determined subcellular location of PTRF and, therefore, regulated IL-33 release.

Regulation of Pol II Pausing Is Involved in Daily Gene Transcription in the Mouse Liver.

The circadian clock orchestrates gene expression rhythms. Regulation at the level of gene transcription is essential for molecular and cellular rhythms. Pol II pause release is a critical step of transcription regulation. However, whether and how Pol II pause release is regulated during daily transcription have not been characterized. In this study, we performed Pol II ChIP-seq across the day in the mouse liver and quantitatively analyzed binding signals within the transcription start site (TSS) region and the gene body. We frequently found discordant changes between Pol II near the TSS ([Pol II]TSS, paused Pol II) and that within the gene body ([Pol II]GB, transcribing Pol II) across the genome, with only [Pol II]GB always reflecting transcription of clock and clock-controlled genes. Accordingly, Pol II traveling ratios of more than 7000 genes showed significant daily changes (>1.5-fold). Therefore, there is widespread regulation of Pol II pausing in the mouse liver. Interestingly, gene transcription rhythms exhibited a bimodal phase distribution. The transcription of ~400 genes peaked near ZT0, coincident with a genome-wide increase in [Pol II]TSS and traveling ratio (TR). The transcription of ~300 other genes peaked ~12 h later, when there was a global decrease in [Pol II]TSS and TR. ChIP-seq against TATA-binding protein (Tbp), a preinitiation complex (PIC) component, revealed that Pol II recruitment mainly played an indirect role in transcriptional output, with transcriptional termination and pause release functioning prominently in determining the fate of initiated Pol II and its pausing status. Taken together, our results revealed a critical, albeit complex role of Pol II pausing control in regulating the temporal output of gene transcription.

Directed evolution and biophysical characterization of a full-length, soluble, human caveolin-1 variant

Protein engineering by directed evolution can alter proteins' structures, properties, and functions. However, membrane proteins, despite their importance to living organisms, remain relatively unexplored as targets for protein engineering and directed evolution. This gap in capabilities likely results from the tendency of membrane proteins to aggregate and fail to overexpress in bacteria cells. For example, the membrane protein caveolin-1 has been implicated in many cell signaling pathways and diseases, yet the full-length protein is too aggregation-prone for detailed mutagenesis, directed evolution, and biophysical characterization. Using a phage-displayed library of full-length caveolin-1 variants, directed evolution with alternating subtractive and functional selections isolated a full-length, soluble variant, termed cavsol, for expression in E. coli. Cavsol folds correctly and binds to its known protein ligands HIV gp41, the catalytic domain of cAMP-dependent protein kinase A, and the polymerase I and transcript release factor. As expected, cavsol does not bind off-target proteins. Cellular studies show that cavsol retains the parent protein's ability to localize at the cellular membrane. Unlike truncated versions of caveolin, cavsol forms large, oligomeric complexes consisting of approximately >50 monomeric units without requiring additional cellular components. Cavsol's secondary structure is a mixture of α-helices and β-strands. Isothermal titration calorimetry experiments reveal that cavsol binds to gp41 and PKA with low micromolar binding affinity (KD). In addition to the insights into caveolin structure and function, the approach applied here could be generalized to other membrane proteins.

Rise in invariant Natural Killer T-17 cells during Bordetella pertussis infection in mice

Abstract Bordetella pertussis is a Gram-negative bacterium known for causing the respiratory disease whooping cough. Whooping cough has recently seen resurgence, especially among children, with the disease’s resolution being delayed. Here, we observed the contribution of invariant Natural Killer T (iNKT) cells in the response to B. pertussis infections. Invariant NKT cells are so called for their invariant chain (Vα14Jα18 in mice) within the T cell receptor, which allows these cells to respond to lipid antigens presented by CD1d molecules. iNKT cells are known to express a variety of transcription factors and release different cytokines, as well as interact with numerous cells of the immune system. Here we hypothesize that IL-17 producing iNKT (iNKT17) cells rise in number during B. pertussis infections to aid in the resolution via an IL-17 driven inflammation. However, due to a pertussis toxin-dependent inhibition, there is a delay in the resolution of the infection. The population of iNKT17 cells, as well as dendritic cells and their expression of CD1d, was assessed via comparison of uninfected to B. parapertussis- and B. pertussis -infected C57BL/6 mice, using a multicolor flow cytometry analysis. The mice infected with pertussis displayed a significant rise in RORγt-positive iNKT cells when compared to uninfected mice, while having reduced IL-17 secretion. These findings indicate a role for iNKT17 cells in the pathogenesis and potential resolution of B. pertussis infection, with the potential for future analysis into iNKT cell knockout studies to determine further understanding of the cell’s function during the infection.

JMJD6 Licenses ERα-Dependent Enhancer and Coding Gene Activation by Modulating the Recruitment of the CARM1/MED12 Co-activator Complex

Whereas the actions of enhancers in gene transcriptional regulation are well established, roles of JmjC-domain-containing proteins in mediating enhancer activation remain poorly understood. Here, we report that recruitment of the JmjC-domain-containing protein 6 (JMJD6) to estrogen receptor alpha (ERα)-bound active enhancers is required for RNA polymerase II recruitment and enhancer RNA production on enhancers, resulting in transcriptional pause release of cognate estrogen target genes. JMJD6 is found to interact with MED12 in the mediator complex to regulate its recruitment. Unexpectedly, JMJD6 is necessary for MED12 to interact with CARM1, which methylates MED12 at multiple arginine sites and regulates its chromatin binding. Consistent with its role in transcriptional activation, JMJD6 is required for estrogen/ERα-induced breast cancer cell growth and tumorigenesis. Our data have uncovered a critical regulator of estrogen/ERα-induced enhancer coding gene activation and breast cancer cell potency, providing a potential therapeutic target of ER-positive breast cancers.

Ptrf transgenic mice exhibit obesity and fatty liver.

Polymerase I and transcript release factor (Ptrf, also known as Cavin1) is an essential component in the biogenesis and function of caveolae. Ptrf knockout mice or patients with PTRF mutations exhibit numerous pathologies including markedly aberrant fuel metabolism, lipodystrophy and muscular dystrophy. In this study, we generated Ptrf transgenic mice to explore its function in vivo. Compared with wild-type (WT) mice, we found that the Ptrf transgenic mice showed obesity with an increased level of ALT (alanine aminotransferase) and AST (aspartate transaminase). Ptrf transgenic mice exhibited severe fat degeneration and a higher degree of fat accumulation in the liver compared with WT mice. Consistently, we found that the expression of the fat synthesis gene, Fasn, was increased in the liver of Ptrf transgenic mice. Thus, Ptrf transgenic mice would be a good model for investigating the molecular mechanism and therapeutic targets of obesity and fatty liver associated diseases.

Expression profiling across wild and cultivated tomatoes supports the relevance of early miR482/2118 suppression for Phytophthora resistance.

Plants possess a battery of specific pathogen resistance (R-)genes. Precise R-gene regulation is important in the presence and absence of a pathogen. Recently, a microRNA family, miR482/2118, was shown to regulate the expression of a major class of R-genes, nucleotide-binding site leucine-rich repeats (NBS-LRRs). Furthermore, RNA silencing suppressor proteins, secreted by pathogens, prevent the accumulation of miR482/2118, leading to an upregulation of R-genes. Despite this transcriptional release of R-genes, RNA silencing suppressors positively contribute to the virulence of some pathogens. To investigate this paradox, we analysed how the regulation of NBS-LRRs by miR482/2118 has been shaped by the coevolution between Phytophthora infestans and cultivated and wild tomatoes. We used degradome analyses and qRT-PCR to evaluate and quantify the co-expression of miR482/2118 and their NBS-LRR targets. Our data show that miR482/2118-mediated targeting contributes to the regulation of NBS-LRRs in Solanum lycopersicum. Based on miR482/2118 expression profiling in two additional tomato species—with different coevolutionary histories with P. infestans—we hypothesize that pathogen-mediated RNA silencing suppression is most effective in the interaction between S. lycopersicum and P. infestans. Furthermore, an upregulation of miR482/2118 early in the infection may increase susceptibility to P. infestans.

Anesthesia for patients with PTRF mutations: a case report

BackgroundPolymeraze I and transcript release factor (PTRF) mutations are a newly recognized disease, which cause congenital generalized lipodystrophy associated with myopathy.Case presentationA 29-year-old man (height 126 cm; weight 22 kg) with a PTRF mutation was scheduled for mandibular dentigerous cystectomy. His primary symptoms were lipodystrophy, myopathy, long QT syndrome, refractory nephrosis, and abnormal lipid metabolism. Defibrillator pads were applied soon after the patient entered the operating room. Anesthesia was induced using continuous administration of dexmedetomidine (4 μg/kg/h) for 15 min; midazolam (7 mg) was added while monitoring the bispectral index and his vital signs. Remifentanil and rocuronium were administered before endotracheal intubation. The surgeon used local anesthesia, and dexmedetomidine and remifentanil were titrated throughout the surgery. The surgery was performed uneventfully, and the patient was extubated following the administration of sugammadex and flumazenil.ConclusionPatients with PTRF mutations require careful anesthetic planning. We planned to administer lipid-free, non-inhalational agents for the induction and maintenance of anesthesia. The anesthetic method used for this minor surgery was safe and effective.

Reducing insulin via conditional partial gene ablation in adults reverses diet-induced weight gain.

Excess circulating insulin is associated with obesity in humans and in animal models. However, the physiologic causality of hyperinsulinemia in adult obesity has rightfully been questioned because of the absence of clear evidence that weight loss can be induced by acutely reversing diet-induced hyperinsulinemia. Herein, we describe the consequences of inducible, partial insulin gene deletion in a mouse model in which animals have already been made obese by consuming a high-fat diet. A modest reduction in insulin production/secretion was sufficient to cause significant weight loss within 5 wk, with a specific effect on visceral adipose tissue. This result was associated with a reduction in the protein abundance of the lipodystrophy gene polymerase I and transcript release factor (Ptrf; Cavin) in gonadal adipose tissue. RNAseq analysis showed that reduced insulin and weight loss also associated with a signature of reduced innate immunity. This study demonstrates that changes in circulating insulin that are too fine to adversely affect glucose homeostasis nonetheless exert control over adiposity.—Page, M. M., Skovsø, S., Cen, H., Chiu, A. P., Dionne, D. A., Hutchinson, D. F., Lim, G. E., Szabat, M., Flibotte, S., Sinha, S., Nislow, C., Rodrigues, B., Johnson, J. D. Reducing insulin via conditional partial gene ablation in adults reverses diet-induced weight gain.

Expression of Polymerase I and Transcript Release Factor (PTRF) in Lung Adenocarcinoma

Aim: In our study we found the Lung cancer is a most common malignant tumor and important cause of cancerrelated death worldwide. Lung Adenocarcinoma is the most ordinary type of lung cancer, accounting for about 20-30% of lung cancer. The aims of this study to investigate the expression of PTRF in lung adenocarcinoma and determine if the loss of PTRF expression occur with the progression of lung adenocarcinoma. Material and Methods: Immunohistochemistry and western blot were used to verify the PTRF expression in lung adenocarcinoma (LADC) and normal lung (NL). And PTRF expression status was also detected in the lung adenocarcinoma cells by western blot. Results: Totally 41 differentially expression proteins were identified. Eighteen proteins are up regulated in the lung adenocarcinoma and 23 proteins are down regulated in the lung adenocarcinoma. Western blot and IHC shows the PTRF expression is down regulated in the lung adenocarcinoma. PTRF expression has close relationship with the gender and T stage. Conclusion: PTRF expression is down-regulated in lung adenocarcinoma tissue and lung carcinoma cells and the loss of PTRF expression occur with progression of lung adenocarcinoma. PTRF expression has a close relationship with gender and T stage of lung adenocarcinoma. PRTF may be apotential target in the future.

The role of PTRF/Cavin1 as a biomarker in both glioma and serum exosomes.

Exosomes play critical roles in intercellular communication in both nearby and distant cells in individuals and organs. Polymerase I and transcript release factor (PTRF), also known as Cavin1, has previously been described as a critical factor in caveola formation, and aberrant PTRF expression has been reported in various malignancies. However, the function of PTRF in tumor progression remains controversial, and its role in glioma is poorly understood. In this study, we report that PTRF is associated with malignancy grade and poor prognosis in glioma patients. Our previous study using two proteomics methods, tandem mass tag (TMT) and data-independent acquisition (DIA), showed that EGFRvIII overexpression increased PTRF expression at the protein level. In contrast, blocking PI3K and AKT using LY294002 and MK-2206, respectively, decreased PTRF expression, showing that PTRF is regulated in the EGFR/PI3K/AKT pathway. ChIP-PCR analysis showed that PTRF is transcriptionally regulated by the H3K4me3 and H3K27me3 modifications. Furthermore, PTRF overexpression increased exosome secretion and induced cell growth in vitro. More importantly, overexpressing PTRF induced the malignancy of nearby cells in vivo, suggesting that PTRF alters the microenvironment through intercellular communication via exosomes. Furthermore, analysis of clinical samples showed a positive correlation between tumor grade and PTRF expression in both tumor tissues and exosomes isolated from blood harvested from glioma patients, and PTRF expression in exosomes isolated from the sera of GBM patients was decreased after surgery. In conclusion, PTRF serves as a promising biomarker in both tumor samples and serum exosomes, thus facilitating the detection of glioma and potentially serving as a therapeutic target for glioblastoma multiforme.

WNK1 kinase and the termination factor PCF11 connect nuclear mRNA export with transcription.

Nuclear gene transcription is coordinated with transcript release from the chromatin template and messenger RNA (mRNA) export to the cytoplasm. Here we describe the role of nuclear-localized kinase WNK1 (with no lysine [K] 1) in the mammalian mRNA export pathway even though it was previously established as a critical regulator of ion homeostasis in the cytoplasm. Our data reveal that WNK1 phosphorylates the termination factor PCF11 on its RNA polymerase II (Pol II) C-terminal domain (CTD)-interacting domain (CID). Furthermore, phosphorylation of the PCF11 CID weakens its interaction with Pol II. We predict that WNK1 and the associated phosphorylation of the PCF11 CID act to promote transcript release from chromatin-associated Pol II. This in turn facilitates mRNA export to the cytoplasm.

Caveolin 1 restricts Group A Streptococcus invasion of nonphagocytic host cells.

Caveolae are composed of 2 major proteins, caveolin 1 (CAV1) and cavin 1 or polymerase transcript release factor I (CAVIN1). Here, we demonstrate that CAV1 levels modulate invasion of Group A Streptococcus (GAS) into nonphagocytic mammalian cells. GAS showed enhanced internalisation into CAV1-knockout mouse embryonic fibroblasts and CAV1 knockdown human epithelial HEp-2 cells, whereas overexpression of CAV1 in HEp-2 cells reduced GAS invasion. This effect was not dependent on the expression of the GAS fibronectin binding protein SfbI, which had previously been implicated in caveolae-mediated uptake. Nor was this effect dependent on CAVIN1, as knockout of CAVIN1 in mouse embryonic fibroblasts resulted in reduced GAS internalisation. Although CAV1 restricted GAS invasion into host cells, we observed only minimal association of invading GAS (strain M1T15448 ) with CAV1 by immunofluorescence and very low association of invading M1T15448 with caveolae by transmission electron microscopy. These observations suggest that physical interaction with caveolae is not needed for CAV1 restriction of invading GAS. An indirect mechanism of action is also consistent with the finding that changing membrane fluidity reverses the increased invasion observed in CAV1-null cells. Together, these results suggest that CAV1 protects host cells against GAS invasion by a caveola-independent mechanism.

Abstract 077: Angiotensinogen in Neurons of the Arcuate Nucleus May Regulate Metabolic Rate in Mice

Recent studies from our laboratory have demonstrated that angiotensin II (ANG) type 1A receptors (AT1A) within the arcuate nucleus, expressed in the subset of neurons which express both the leptin receptor (LepR) and agouti-related peptide (AgRP), are critically involved in the control of thermogenic adipose sympathetic nerve activity (SNA) and resting metabolic rate (RMR) by leptin. This mechanism appears to involve AT1A-mediated suppression of gamma-aminobutyric acid (GABA) synthesis and packaging in AgRP neurons of the arcuate nucleus (ARC). It remains unclear, however, how leptin/LepR signaling results in AT1A activation within AgRP neurons. We hypothesize that LepR signaling results in increased transcription and local release of angiotensinogen (AGT) within the ARC, and consequently increased autocrine or paracrine ANG signaling within the ARC. Fluorescent in situ hybridization (RNAscope) uncovered expression of AGT mRNA in various cells of the ARC of C57BL/6J mice, including cells expressing mRNA for LepR, AgRP, proopiomelanocortin (POMC), insulin II, or glial fibrillary acidic protein, supporting local generation of AGT within the ARC. In silico re-analysis of a publically-available gene expression dataset interrogating individual cell types of the mouse hypothalamus (GSE74672) similarly uncovered expression of AGT in astrocytes, microglia, and many neuronal cell types of the ARC, including those expressing AgRP and POMC. Stimulation of immortalized mouse hypothalamic AgRP-like cell cultures (N47) with leptin may increase AGT mRNA (100 nM, 4 hrs; n=4 passages, 1.0 (0.6-1.8) vs 2.0 (1.2-3.6) fold, p=0.19). Further, using Cre-lox technology, mice lacking AGT in LepR- or AgRP-expressing cells (AGT LepR-KO or AGT AgRP-KO mice) were generated. In females at 8 weeks of age fed a chow diet (Teklad 7013), trends toward increased fat mass were noted (control n=28, 0.7±0.1; AGT LepR-KO n=2, 1.0±0.5; AGT AgRP-KO n=3, 1.0±0.2 g), despite normal food intake (13.5±0.6, 16.3±0.0, 12.4±0.8 kcal/d) and digestive efficiency (79±1, 83±0, 80±1 %). Collectively, these findings support local production of ANG peptides within the ARC, and may indicate transcriptional regulation of AGT by leptin and a role for ARC AGT in the control of energy expenditure.