ResearchPad - signaling https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[PINK1-dependent phosphorylation of Serine111 within the SF3 motif of Rab GTPases impairs effector interactions and LRRK2-mediated phosphorylation at Threonine72]]> https://www.researchpad.co/article/elastic_article_13881 Loss of function mutations in the PTEN-induced kinase 1 (PINK1) kinase are causal for autosomal recessive Parkinson's disease (PD) whilst gain of function mutations in the LRRK2 kinase cause autosomal dominant PD. PINK1 indirectly regulates the phosphorylation of a subset of Rab GTPases at a conserved Serine111 (Ser111) residue within the SF3 motif. Using genetic code expansion technologies, we have produced stoichiometric Ser111-phosphorylated Rab8A revealing impaired interactions with its cognate guanine nucleotide exchange factor and GTPase activating protein. In a screen for Rab8A kinases we identify TAK1 and MST3 kinases that can efficiently phosphorylate the Switch II residue Threonine72 (Thr72) in a similar manner as LRRK2 in vitro. Strikingly, we demonstrate that Ser111 phosphorylation negatively regulates the ability of LRRK2 but not MST3 or TAK1 to phosphorylate Thr72 of recombinant nucleotide-bound Rab8A in vitro and demonstrate an interplay of PINK1- and LRRK2-mediated phosphorylation of Rab8A in transfected HEK293 cells. Finally, we present the crystal structure of Ser111-phosphorylated Rab8A and nuclear magnetic resonance structure of Ser111-phosphorylated Rab1B. The structures reveal that the phosphorylated SF3 motif does not induce any major changes, but may interfere with effector-Switch II interactions through intramolecular H-bond formation and/or charge effects with Arg79. Overall, we demonstrate antagonistic regulation between PINK1-dependent Ser111 phosphorylation and LRRK2-mediated Thr72 phosphorylation of Rab8A indicating a potential cross-talk between PINK1-regulated mitochondrial homeostasis and LRRK2 signalling that requires further investigation in vivo.

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<![CDATA[Decyl caffeic acid inhibits the proliferation of colorectal cancer cells in an autophagy-dependent manner <i>in vitro</i> and <i>in vivo</i>]]> https://www.researchpad.co/article/elastic_article_13874 The treatment of human colorectal cancer (CRC) cells through suppressing the abnormal survival signaling pathways has recently become a significant area of focus. In this study, our results demonstrated that decyl caffeic acid (DC), one of the novel caffeic acid derivatives, remarkedly suppressed the growth of CRC cells both in vitro and in vivo. The inhibitory effects of DC on CRC cells were investigated in an in vitro cell model and in vivo using a xenograft mouse model. CRC cells were treated with DC at various dosages (0, 10, 20 and 40 μM), and cell survival, the apoptotic index and the autophagy level were measured using an MTT assay and flow cytometry analysis, respectively. The signaling cascades in CRC were examined by Western blot assay. The anti-cancer effects of DC on tumor growth were examined by using CRC HCT-116 cells implanted in an animal model. Our results indicated that DC differentially suppressed the growth of CRC HT-29 and HCT-116 cells through an enhancement of cell-cycle arrest at the S phase. DC inhibited the expression of cell-cycle regulators, which include cyclin E and cyclin A proteins. The molecular mechanisms of action were correlated to the blockade of the STAT3 and Akt signaling cascades. Strikingly, a high dosage of DC prompted a self-protection action through inducing cell-dependent autophagy in HCT-116 cells. Suppression of autophagy induced cell death in the treatment of DC in HCT-116 cells. DC seemed to inhibit cell proliferation of CRC differentially, and the therapeutic advantage appeared to be autophagy dependent. Moreover, consumption of DC blocked the tumor growth of colorectal adenocarcinoma in an experimental animal model. In conclusion, our results suggested that DC could act as a therapeutic agent through the significant suppression of tumor growth of human CRC cells.

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<![CDATA[<i>Ehrlichia chaffeensis</i> TRP120-mediated ubiquitination and proteasomal degradation of tumor suppressor FBW7 increases oncoprotein stability and promotes infection]]> https://www.researchpad.co/article/elastic_article_13827 E. chaffeensis is an obligately intracellular bacterium that replicates in mononuclear phagocytes by secreting effectors that manipulate host cell processes and exploit evolutionarily conserved pathways. This investigation reveals the complex and expanding role of the E. chaffeensis TRP120 moonlighting effector as a ubiquitin (Ub) ligase targeting host nuclear proteins. Herein, we demonstrate that E. chaffeensis TRP120 HECT Ub ligase targets the nuclear tumor suppressor Skp1-cullin-1-FBOX E3 ubiquitin (Ub) ligase complex substrate recognition subunit, F-BOX and WD domain repeating-containing 7 (FBW7) for degradation. FBW7 is a central regulator of broadly acting host cell oncoproteins involved in cell proliferation and survival. The reduction in FBW7 through TRP120-mediated ubiquitination increases cellular oncoprotein levels and promotes E. chaffeensis infection. This study illuminates novel bacterial effector-host interactions, the importance and interplay of both host and bacterial Ub ligases and the Ub-proteasome system for infection, and mechanisms whereby evolutionarily conserved signaling pathways are hijacked by obligately intracellular pathogens.

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<![CDATA[From sepsis to acute respiratory distress syndrome (ARDS): emerging preventive strategies based on molecular and genetic researches]]> https://www.researchpad.co/article/elastic_article_9221 A healthy body activates the immune response to target invading pathogens (i.e. viruses, bacteria, fungi, and parasites) and avoid further systemic infection. The activation of immunological mechanisms includes several components of the immune system, such as innate and acquired immunity. Once any component of the immune response to infections is aberrantly altered or dysregulated, resulting in a failure to clear infection, sepsis will develop through a pro-inflammatory immunological mechanism. Furthermore, the severe inflammatory responses induced by sepsis also increase vascular permeability, leading to acute pulmonary edema and resulting in acute respiratory distress syndrome (ARDS). Apparently, potential for improvement exists in the management of the transition from sepsis to ARDS; thus, this article presents an exhaustive review that highlights the previously unrecognized relationship between sepsis and ARDS and suggests a direction for future therapeutic developments, including plasma and genetic pre-diagnostic strategies and interference with proinflammatory signaling.

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<![CDATA[Post-translational modifications and stress adaptation: the paradigm of FKBP51]]> https://www.researchpad.co/article/elastic_article_9189 Adaptation to stress is a fundamental requirement to cope with changing environmental conditions that pose a threat to the homeostasis of cells and organisms. Post-translational modifications (PTMs) of proteins represent a possibility to quickly produce proteins with new features demanding relatively little cellular resources. FK506 binding protein (FKBP) 51 is a pivotal stress protein that is involved in the regulation of several executers of PTMs. This mini-review discusses the role of FKBP51 in the function of proteins responsible for setting the phosphorylation, ubiquitination and lipidation of other proteins. Examples include the kinases Akt1, CDK5 and GSK3β, the phosphatases calcineurin, PP2A and PHLPP, and the ubiquitin E3-ligase SKP2. The impact of FKBP51 on PTMs of signal transduction proteins significantly extends the functional versatility of this protein. As a stress-induced protein, FKBP51 uses re-setting of PTMs to relay the effect of stress on various signaling pathways.

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<![CDATA[Redox signalling and ageing: insights from <i>Drosophila</i>]]> https://www.researchpad.co/article/elastic_article_9185 Ageing and age-related diseases are major challenges for the social, economic and healthcare systems of our society. Amongst many theories, reactive oxygen species (ROS) have been implicated as a driver of the ageing process. As by-products of aerobic metabolism, ROS are able to randomly oxidise macromolecules, causing intracellular damage that accumulates over time and ultimately leads to dysfunction and cell death. However, the genetic overexpression of enzymes involved in the detoxification of ROS or treatment with antioxidants did not generally extend lifespan, prompting a re-evaluation of the causal role for ROS in ageing. More recently, ROS have emerged as key players in normal cellular signalling by oxidising redox-sensitive cysteine residues within proteins. Therefore, while high levels of ROS may be harmful and induce oxidative stress, low levels of ROS may actually be beneficial as mediators of redox signalling. In this context, enhancing ROS production in model organisms can extend lifespan, with biological effects dependent on the site, levels, and specific species of ROS. In this review, we examine the role of ROS in ageing, with a particular focus on the importance of the fruit fly Drosophila as a powerful model system to study redox processes in vivo.

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<![CDATA[Cross-talk between redox signalling and protein aggregation]]> https://www.researchpad.co/article/elastic_article_9183 It is well established that both an increase in reactive oxygen species (ROS: i.e. O2•−, H2O2 and OH), as well as protein aggregation, accompany ageing and proteinopathies such as Parkinson's and Alzheimer's disease. However, it is far from clear whether there is a causal relation between the two. This review describes how protein aggregation can be affected both by redox signalling (downstream of H2O2), as well as by ROS-induced damage, and aims to give an overview of the current knowledge of how redox signalling affects protein aggregation and vice versa. Redox signalling has been shown to play roles in almost every step of protein aggregation and amyloid formation, from aggregation initiation to the rapid oligomerization of large amyloids, which tend to be less toxic than oligomeric prefibrillar aggregates. We explore the hypothesis that age-associated elevated ROS production could be part of a redox signalling-dependent-stress response in an attempt to curb protein aggregation and minimize toxicity.

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<![CDATA[Cell signaling and cytomegalovirus reactivation: what do Src family kinases have to do with it?]]> https://www.researchpad.co/article/elastic_article_9180 Primary infection with human cytomegalovirus (HCMV) is usually asymptomatic and leads to the establishment of lifelong latent infection. A major site of latency are the CD34+ hematopoietic progenitor cells. Importantly, normal cellular differentiation of CD34+ cells to a macrophage or dendritic cell phenotype is concomitant with viral reactivation. Molecular studies of HCMV latency have shown that the latent viral genome is associated with histone proteins and that specific post-translational modifications of these histones correlates with the transcriptional activity of the genome arguing that expression of key viral genes that dictate latency and reactivation are subject to the rules of the histone code hypothesis postulated for the regulation of eukaryotic gene expression. Finally, many studies now point to a key role for multiple signaling pathways to provide the cue for HCMV reactivation. The challenge now is to understand the complex interplay between cell identity, transcriptional regulation and cell signaling that occurs to promote reactivation and, additionally, how HCMV may further manipulate these events to support reactivation. Understanding how HCMV utilizes these pathways to drive HCMV reactivation will provide new insight into the mechanisms that govern viral and host gene expression and, potentially, illuminate new, host-directed, therapeutic opportunities to support our attempts to control this important medical pathogen of immune-compromised individuals.

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<![CDATA[Differential effects of ‘resurrecting' Csp pseudoproteases during <i>Clostridioides difficile</i> spore germination]]> https://www.researchpad.co/article/elastic_article_9173 Clostridioides difficile is a spore-forming bacterial pathogen that is the leading cause of hospital-acquired gastroenteritis. C. difficile infections begin when its spore form germinates in the gut upon sensing bile acids. These germinants induce a proteolytic signaling cascade controlled by three members of the subtilisin-like serine protease family, CspA, CspB, and CspC. Notably, even though CspC and CspA are both pseudoproteases, they are nevertheless required to sense germinants and activate the protease, CspB. Thus, CspC and CspA are part of a growing list of pseudoenzymes that play important roles in regulating cellular processes. However, despite their importance, the structural properties of pseudoenzymes that allow them to function as regulators remain poorly understood. Our recently solved crystal structure of CspC revealed that its pseudoactive site residues align closely with the catalytic triad of CspB, suggesting that it might be possible to ‘resurrect' the ancestral protease activity of the CspC and CspA pseudoproteases. Here, we demonstrate that restoring the catalytic triad to these pseudoproteases fails to resurrect their protease activity. We further show that the pseudoactive site substitutions differentially affect the stability and function of the CspC and CspA pseudoproteases: the substitutions destabilized CspC and impaired spore germination without affecting CspA stability or function. Thus, our results surprisingly reveal that the presence of a catalytic triad does not necessarily predict protease activity. Since homologs of C. difficile CspA occasionally carry an intact catalytic triad, our results indicate that bioinformatic predictions of enzyme activity may underestimate pseudoenzymes in rare cases.

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<![CDATA[MON-721 Crude Protein of Pyropia Yezoensis Protects Against Tumor Necrosis Factor-á-Induced Myotube Atrophy by Regulating the Mitogen-Activated Protein Kinase and Nuclear Factor-Kappab Signaling Pathways in C2C12 Myotubes]]> https://www.researchpad.co/article/elastic_article_8812 Proinflammatory cytokines induce ubiquitin-proteasome-dependent proteolysis by activating intracellular factors in skeletal muscle, leading to muscle atrophy. Therefore, we investigated the protective effect of Pyropia yezoensis crude protein (PYCP) on tumor necrosis factor (TNF)-α-induced muscle atrophy in vitro. Mouse skeletal muscle C2C12 myotubes were treated for 48 h with TNF-α (20 ng/mL) in the presence or absence of PYCP (25, 50, and 100 μg/mL). PYCP at concentrations up to 100 μg/mL did not affect cell viability. Exposure to TNF-α for 48 h significantly decreased the diameter of myotubes, which was increased by treatment with 25, 50, and 100 μg/mL PYCP. PYCP inhibited TNF-α-induced intracellular reactive oxygen species accumulation in C2C12 myotubes. In addition, PYCP significantly reduced the levels of phosphorylated p38 and JNK. Moreover, by inhibiting the degradation of inhibitor of kappaB-α, PYCP significantly suppressed the TNF-α-induced increased transcriptional activity and nuclear translocation of nuclear factor-kappaB (NF-κB). Furthermore, PYCP inhibited E3-ubiquitin ligases in TNF-α-treated C2C12 myotubes. In conclusion, PYCP ameliorated TNF-α-induced muscle atrophy by inhibiting the mitogen-activated protein kinase-mediated NF-κB pathway, indicating that it has therapeutic potential for related disorders.

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<![CDATA[OR07-03 Continuous Subcutaneous Delivery of RhPTH(1-84) by Pump in Adults with Hypoparathyroidism]]> https://www.researchpad.co/article/elastic_article_8785 More than 80,000 people in the United States have hypoparathyroidism, a disease of low or absent parathyroid hormone (PTH) leading to hypocalcemia and hyperphosphatemia. Conventional treatment with oral calcium and active vitamin D increases serum calcium concentrations but does not replace the physiologic functions of PTH. Once-daily subcutaneous injections of recombinant human (rh) PTH(1-84) were recently approved for the treatment of hypoparathyroidism, but are not consistent in correcting biochemical abnormalities and alleviating symptoms for all patients. In cases in which single or multiple daily injections of rhPTH(1-84) are insufficient for controlling symptoms, continuous subcutaneous infusion via insulin pump is used as a therapeutic alternative. Pump therapy with PTH(1-34) has some support in the literature as an effective form of treatment for hypoparathyroidism.1However, the effects of pump therapy with rhPTH(1-84) in patients with hypoparathyroidism have not been reported. Five women with chronic postsurgical hypoparathyroidism who received treatment at three different endocrine outpatient clinics in the United States were transitioned from multiple daily injections of rhPTH(1-84) to continuous delivery of rhPTH(1-84) using the Omnipod insulin pump. The patients’ ages ranged from 27 to 60 years old and all had had hypoparathyroidism for at least 5 years. All of the patients were transitioned from conventional therapy with oral calcium and calcitriol to subcutaneous injections of rhPTH(1-84), and then switched to continuous subcutaneous administration using an insulin pump. In all five patients, increased serum calcium concentrations and decreased serum phosphate concentrations were observed with increased frequency of PTH administration. Serum calcium concentrations were within the normal to high-normal range and serum phosphate concentrations were in the normal range on pump therapy. Urinary calcium was well-controlled (<250 mg/day) in four of the five patients. All of the women reported a decrease in symptoms while receiving pump-administered rhPTH(1-84), including a lower incidence of fatigue, brain fog, tingling, and muscle cramps compared to standard therapy and daily injections. This is the first report of patients with hypoparathyroidism on long-term therapy with continuously infused subcutaneous rhPTH(1-84) using a pump. Pump therapy improved key parameters of mineral metabolism; normalizing serum calcium in all patients and urinary calcium in four out of five patients. Clinical trials with larger cohorts are needed to confirm the efficacy of this promising mode of administration of rhPTH(1-84). Reference: 1. Winer KK. Advances in the treatment of hypoparathyroidism with PTH 1-34. Bone. 2019;120:535-541.

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<![CDATA[OR07-06 The Roles of GNAQ and GNA11 in Calcium-Sensing Receptor (CaSR) Signalling]]> https://www.researchpad.co/article/elastic_article_8778 The G-protein subunits Gα 11 and Gα q, which share >90% peptide sequence identity and are encoded by the GNA11 and GNAQ genes, respectively, mediate signalling by the calcium-sensing receptor (CaSR), a class C G-protein coupled receptor (GPCR) that regulates extracellular calcium (Ca2+e) homeostasis. Germline Gα 11 inactivating and activating mutations cause familial hypocalciuric hypercalcaemia type-2 (FHH2) and autosomal dominant hypocalcaemia type-2 (ADH2), respectively, but such Gα q mutations have not been reported. We therefore investigated the DiscovEHR cohort database, which has exomes from 51,289 patients with matched phenotyping data, for such GNAQ mutations. The DiscovEHR cohort was examined for rare GNAQ variants, which were transiently expressed in CaSR-expressing HEK293A Gα q/11 knockout cells, and their effects on CaSR-mediated intracellular calcium (Ca2+i) release and MAPK activity, in response to increasing concentrations of extracellular calcium were assessed using a nuclear factor of activated T-cells response element (NFAT-RE) luciferase reporter construct and a serum response element (SRE) luciferase reporter construct, respectively. Responses were compared to those of wild-type (WT), inactivating FHH2-associated GNA11 mutations (Leu135Gln and Phe220Ser), and engineered GNAQ mutations that were equivalent to the FHH2-causing GNA11 mutations. Gα q/11 protein expression was confirmed by Western blot analysis. Six rare missense GNAQ variants (Arg19Trp, Ala110Val, Gln299His, Ala302Ser, Ala331Thr, Val344Ile) were identified in DiscovEHR individuals, all of whom had mean plasma calcium values in the normal range (8.30–10.00 mg/dL). Functional characterisation of all six Gα q variants showed no significant difference to WT Gα q responses, thereby indicating that these variants are unlikely to be disease-causing mutations. In addition, the FHH2-causing GNA11 mutations (Leu135Gln and Phe220Ser) had significantly reduced responses, compared to WT Gα 11; however, this could be compensated by WT Gα q. GNAQ Leu135Gln and Phe220Ser, in contrast to their Gα 11 counterparts, showed no differences in protein expression or signalling responses when compared to WT Gα q. Our study, which provides mechanistic insights into the differences between Gα q and Gα 11, indicates that Gα q, unlike Gα 11, does not play a major role in the pathogenesis of FHH2 or ADH2.

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<![CDATA[SUN-710 Custom Panel to Diagnosis Genetic Endocrine Disorders in a Tertiary Academic Hospital]]> https://www.researchpad.co/article/elastic_article_8748 Next-generation sequencing (NGS) has been transforming the endocrine diagnostic methodology allowing the genetic testing to assume an exploratory role rather than only a confirmatory one. This is possible due to lower costs and increased yield of information. A way to further increase efficiency and sensitivity for variant detection is the use of a sequencing custom panel selecting specific genes for screening. In endocrine disorders, the complex and intricate genotype-phenotype relations and occurrence of diverse comorbidities made the diagnosis challenging. Our aim is to analyze the efficiency of a multigenic panel for molecular diagnosis of endocrine disorders in patients assisted in a tertiary academic hospital, as well as to train academic and medical faculties in the use of molecular tools. Genomic DNA from 282 patients was extracted from blood sample using standard procedures. Sanger method was previously used to screen some candidate genes in half of the patients. The custom panel was designed with 651 genes using the SureDesign tool (Agilent technologies), either associated with the phenotype (OMIM) or candidate genes that englobes developmental (DD), metabolic (MD), and adrenal (AD) disorders. Libraries were prepared with SureSelectXT Target Enrichment kit (Agilent Technologies). The enriched DNA libraries were sequenced in NextSeq 500 (Illumina) with High Output V2 kit (2 x 150 bp). The raw data was aligned to hg19 with BWA-MEM, variant calling was performed using FreeBayes and annotated with ANNOVAR. Filtering took into consideration the rarity (≤1%) of variants in population databases and those in exonic or splice site regions. Variants found were then classified according ACMG/AMP criteria. The categories of Pathogenic (P) and Likely Pathogenic (LP) were considered for molecular diagnosis, while variants of uncertain significance (VUS) were only reported. The average result of 3 runs was: 159Kmm2 of cluster density, 76.5 % of Q30 and 76.6 Gb of data were generated. The mean coverage depth of the targeted regions in panel sequencing data was 237x (SD±110x), with at least 96.3% of the sequenced bases being covered more than 20-fold. Out of the 282 patients, we identified 65 LP/P variants (23%), 22 VUS (8%) and 195 remained undiagnosed (69%). Considering the solved cases, 54 (19.1%) have DD, 6 (2.1%) have MD and 5 (1.8%) have AD. Taking into account that half of the patients had already been previously screened, the data enable new findings in known genes. The application of a multigenic panel aids the training of medical faculty in an academic hospital by showing the big picture of the molecular pathways behind each disorder. This may be particularly helpful considering the higher diagnosis of DD cases. A precise genetic etiology provides improvement in understanding the disease, guides decisions about prevention or treatment, and brings comfort to the affected families.

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<![CDATA[MON-711 Induction of Apolipoprotein A1 Gene Expression by the Rare Sugar Allulose]]> https://www.researchpad.co/article/elastic_article_8671 Apolipoprotein A-I (apo A-I) is the primary protein component of high-density lipoprotein (HDL) and has many well documented properties which promote cardiovascular health. However, clinical trials designed to increase HDL levels by preventing its catabolism have failed in their primary endpoints in decreasing the risk of cardiovascular disease. Alternative strategies to increase de-novo apo A-I production may be more attractive. We recently demonstrated that the rare sugar allulose decreases oxidative stress and endoplasmic reticulum stress in both endothelial cells and hepatocytes. During these studies we demonstrated that allulose also induces apo A-I secretion by HepG2 cells. Apo A-I, albumin, and SP1 levels were measured by Western blot. Apo A-I and glyceraldehyde-3-phosphate (GAPDH) mRNA levels were measured by quantitative real-time polymerase chain reaction. The effect of allulose on apo A-I promoter activity was measured using transient transfection assays with several plasmids containing various segments and mutations in the apo A-I gene promoter. Apo A-I protein and mRNA levels in cells treated with allulose increased more than two-fold in a dose-dependent manner. These changes were due to the ability of allulose to induce apo A-I gene promoter activity. Using a series of deletion constructs, an allulose-response element was identified in the apo A-I gene promoter which was previously shown to confer induction of apo A-I gene expression by insulin and epidermal growth factor (EGF), the insulin response core element (IRCE). Mutation of the IRCE decreased the ability of allulose and insulin to induce apo A-I promoter activity. Allulose treatment also increased expression of the transcription factor SP1, which had been shown previously be essential for the effects of insulin and EGF on apo A-I promoter activity. In conclusion, allulose increased apo A-I gene expression in HepG2 hepatocytes. This effect was mediated by the IRCE in the apo A-I gene promoter and the transcription factor SP1. The rare sugar allulose may have novel anti-atherogenic properties, in part, by increasing HDL levels.

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<![CDATA[MON-708 Characterizing DNA Methylation Signatures in Adipose Tissue from Metabolic Impaired Asymptomatic Individuals]]> https://www.researchpad.co/article/elastic_article_8669 Obesity remains as a global epidemic characterized by progressive metabolic dysregulation in glucose homeostasis. Along with a genetic association in the development of T2D, epigenetic regulation has been suggested as a significant contributor in altered gene expression. Recent studies have described DNA methylation changes in insulin-sensitive tissues involved in T2D pathogenesis, however epigenetic dynamics on early stages to metabolic alterations is still unclear.

We investigated potential DNA methylation signatures in 34 asymptomatic individuals from the GEMM family study. We compared differentially methylated CpG sites (DMC: B value>0 and delta Beta >|10%|; Infinium EPIC array) from subcutaneous adipose tissue (SCAT) in different groups of individuals according to BMI (kg/m2) and HbA1c (%) levels as follow: Group A Control (C): n=9, 22.0±1.9 kg/m2, 4.8±0.3%; Group B Overweight (OW) with normal HbA1c: n=6, 27.8±1.6 kg/m2, 5±0.2%; Group C Obese (OB) with normal HbA1c: n=6, 34.6±4.2 kg/m2, 5.2±0.2%; Group D Prediabetes (PD): n=7, 31.1±5.7 kg/m2, 5.9±0.2% and Group E T2D: n=6, 30.6±7.3 kg/m2, 7.2±0.9%.

We found 43 overlapping genes with shared pathways in all groups, mainly those related to metabolism and adipogenesis. We also documented particular altered methylated genes, in each group (OW: 386, OB:1005, PD:76 and T2D:189). Pathway enrichment analysis in OB and T2D was mainly related to glucose metabolism, while in OW and PD was NOTCH signaling. All groups displayed a consistent hypermethylation in RARA, ESR1 and NCOR2, well known genes involved in lipid metabolism. Additionally, we describe for the first time, a progression toward hypomethylation in ARHGAP15 and MTAP, related with an impaired metabolic status. Otherwise, analysis of overlapping CpG sites revealed a consistently hypermethylated state in OW (86.42%), OB (86.48%) and PD (51.72%), in contrast with the hypomethylation state (56.3%) observed in the T2D group, previously observed elsewhere (1).

In conclusion, comparison of methylation in SCAT obtained from OW, OB, PD and T2D individuals, display potential pathways and DMC signatures specific in each group. Common novel overlapping genes in global DNA methylation profiles of SCAT, were also observed.

Reference: (1) Barajas-Olmos et al., BMC Med Genet. 2018 Feb 21;19(1):1-8.

Nothing to Disclose: FE, FB, AM, EH, GEMM, ER, RB, LO.

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<![CDATA[SUN-719 The Impact of FOXA3 on Testicular Steroidogenesis]]> https://www.researchpad.co/article/elastic_article_8656 The Forkhead box(Fox) transcription factors are evolutionarily conserved in organisms and regulate diverse biological processes during development as well as adult life. Among the Fox family, FoxA subfamily members Foxa1-3 have been termed `pioneer’ transcription factors as they bind both nucleosome-bound and nucleosome-free DNA targets with the same recognition site. Foxa3 is the only member of FoxA subfamily that is expressed in both male and female gonads. In the testis, Foxa3 is expressed in spermatids and interstitial Leydig cells. We focused our study to elucidate the role of FOXA3 in Leydig cells and its impact on testicular steroidogenesis. Expression of FOXA3 dramatically decreased in mouse Leydig cells during testicular development. In addition, the time-dependent expression of FOXA3 showed an opposite pattern to that of steroidogenic genes in cAMP-induced primary Leydig cells. Meanwhile, Nur77 is among the prime regulators of steroidogenesis in the testicular Leydig cells. Overexpression of FOXA3 in MA-10 cells (mouse Leydig tumor cell line) repressed the cAMP-induced Nur77 promoter activity, which further resulted in the reduced activity of Nur77-target steroidogenic gene promoters (StAR, CYP17A1and 3β-HSD). Similar to above results, the expression of Nur77 and its target genes,StAR, 3β-HSD and CYP11A1, were repressed by adenovirus-mediated overexpression of FOXA3 in mouse primary Leydig cells, although the expression of CYP17A1, another steroidogenic gene, was differentially affected. These results suggest that FOXA3 locally regulates the expression of steroidogenic genes through Nur77 during testicular development.

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<![CDATA[MON-725 Transcriptome Profiling in Postnatal Pituitary Gland Identifies Cell Type-Driven Sex-Specific Changes]]> https://www.researchpad.co/article/elastic_article_8581 The pituitary gland is integral to the regulation of growth, metabolism, puberty, reproduction, and stress responses. Previously, we found that many genes associated with age-at-menarche in genome-wide association studies (GWAS) displayed increasingly sex-biased expression across the pubertal transition in the mouse pituitary. However, whether this trend exists beyond puberty-related genes was not known. In addition, the regulatory mechanisms underlying these gene expression changes remained to be explored. To answer these questions, we profiled the transcriptome, including microRNAs, of mouse pituitary in both sexes across pubertal transition in an unbiased manner and leveraged a recently published pituitary single cell transcriptome to explore cellular composition changes. We found that the most dynamic temporal changes in both mRNA and miRNA expression occur prior to puberty, underscoring a role for regulation of early pituitary postnatal development. We also observed ~900 genes displaying sex-biased expression patterns, arising during early development and becoming increasingly biased across puberty, including known sex-biased genes such as Fshb and Lhb. However, sex differences in miRNA expression are less pronounced, only 13 miRNAs were found to be sex-biased, suggesting lesser contribution of miRNAs to sex-biased gene expression relative to other forms of regulation. To assess whether pituitary cellular composition could underlie changes in gene expression across pubertal transition, we performed single cell deconvolution of our bulk pituitary gland gene expression. Interestingly, we found that sex differences in cell proportions were estimated to emerge across puberty: a greater proportion of lactotropes was found among females, and greater proportions of gonadotropes and somatotropes were found among males. We observed sex-biased expression patterns of marker genes for these cell types, including Prl, Fshb, and Gh. This finding suggests that cell proportion differences between sexes likely contribute to whole pituitary transcriptome changes we observed, however, to what extent remains to be studied. Together our study indicates that miRNAs play a substantial role in regulation of pituitary postnatal development but that differences in cellular composition may contribute more robustly to sex-biased gene expression.

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<![CDATA[SUN-712 Familial 46, XY Complete Female External Sex Development with a Non-Mosaic Inherited SRY Gene Variation]]> https://www.researchpad.co/article/elastic_article_8569 Context: SRY, an architectural transcription factor containing a SOX-related high-mobility group (HMG) box, initiates testis formation in the mammalian bipotential gonadal ridge. Inherited human SRY mutations can be associated with differences in sexual differentiation (DSD) with variable phenotypes in a family.

Objective: To describe the clinical, histopathological and molecular features of a novel inherited SRY allele (pMet64Val; consensus box position 9) observed within an extensive pedigree: two 46, XY sisters with primary amenorrhea (16 and 14 years of age; probands P1 and P2), their normal father and brother, and an affected paternal XY grandaunt.

Design, Setting, Participants and Outcome Measurements: Following DNA sequencing to identify the SRY mutation, hormonal studies of the probands and histopathological examination of their gonads were performed. Functional consequences of p.Met64Val (and other mutations at this site) were also investigated.

Results: Breast development in P1 and P2was Tanner II and IV, respectively. Müllerian structures and gonads resembling ovaries were found in each sister. Histopathology revealed gonadal dysgenesis, gonadoblastoma and dysgerminoma. AMH/MIS, P450 SCC, and P450 aromatase were expressed in gonadoblastoma tissues. Variant p.Met64Val impaired Sox9 transcriptional activation associated with attenuated occupancy of the testis-specific enhancersEnh13 and TESCO.

Conclusion: The partial biological activity of p.Met64Val SRY, maintained at the threshold of SRY function, rationalizes opposing paternal and proband phenotypes (the “the father-daughter paradox”).Sex steroids biosynthesis by gonadoblastoma may delay genetic diagnosis and recognition of gonadal tumors. Quantitative assessment of inherited SRY alleles highlights the tenuous transcriptional threshold of developmental decision-making in the bipotential gonadal ridge.

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<![CDATA[OR24-07 Fetal Sex Impacts First Trimester Maternal-Fetal Communication in Humans]]> https://www.researchpad.co/article/elastic_article_8549 The placenta serves as a regulator of fetal growth throughout pregnancy. Signaling at the maternal-fetal interface is critical during placentation and lays the groundwork for placenta function, affecting pregnancy outcomes. Fetal growth is impacted by fetal sex, with males larger than females, and maternal gestational diabetes and obesity independently increase the risk of macrosomia in male fetuses only. We previously demonstrated differentially expressed genes (DEGs) among sexes involves ancient canonical pathways and metabolic functions in placenta tissue. As these are likely impacted by signaling at the maternal-fetal interface, our aim here was to identify sex differences in signaling at the maternal-fetal interface and among individual cell types within the placenta to explain these differences. RNA-sequencing of first trimester placenta and maternal decidua as well as single cell RNA-sequencing in first trimester placenta was performed in ongoing pregnancies. We identified 91 sexually dimorphic receptor-ligand pairs across the maternal-fetal interface. From these, 35 of 115 receptors and/or ligand genes were also found to be upstream regulators of pathways critical in sexually dimorphic placentation which may define regulation. Single cell analysis identified five major cell types (trophoblasts, stromal cells, hofbauer cells, antigen presenting cells, and endothelial cells), and all had sexually dimorphic genes. Among individual cell types, ligands from the CC-family of cytokines were most highly representative in females, with their corresponding receptors present on the maternal surface. Furthermore, upstream regulator analysis of sexually dimorphic genes demonstrated TGFβ1 and estradiol to significantly affect all cell types. Dihydrotestosterone, which is produced by the male fetus, was an upstream regulator that was most significant for the trophoblast population. In addition, gene ontology enrichment analysis identified distinctive enriched functions between male and female trophoblasts, with cytokine mediated signaling pathways most representative. MUC15 and NOTUM were the most highly expressed sexually dimorphic autosomal genes found in distinct cell types of the trophoblast population, cell types critical for placentation and nutrient exchange. Thus, differences in hormone and immune signaling pathways may account for differential gene expression and differences in trophoblast function during placentation, which may in turn explain developmental differences, including fetal size, well-being, and overall outcomes.

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<![CDATA[OR01-04 Kruppel-Like Factors 9 and 13 Cooperate to Maintain Mammalian Neuronal Differentiation]]> https://www.researchpad.co/article/elastic_article_8528 During development of the central nervous system, neural cells respond to several external cues that influence cell proliferation, differentiation, axonal growth and synaptogenesis. Thyroid hormone plays a critical role in each of these processes. Previously, we showed that Krüppel-like factor 9 (KLF9), a zinc finger transcription factor, is strongly and directly induced by liganded thyroid hormone receptors, and it mediates the actions of thyroid hormone on neuronal differentiation during late fetal development. Here we analyzed the molecular mechanisms by which KLF9 maintains neuronal structure, and inhibits regeneration in juvenile and adult neuronal cells. We also investigated the actions of the closely related transcription factor KLF13, which is paralogous to KLF9. We engineered the adult mouse hippocampus-derived cell line HT22 to control Klf9 or Klf13 expression by addition of doxycycline. We also used CRISPR/Cas9 genome editing to generate Klf9 or Klf13 knock out (KO), and Klf9+Klf13 double KO HT22 cell lines. To induce neurite outgrowth, we treated cells with forskolin (FK)+IBMX, which increases intracellular cAMP; elevated cAMP is a hallmark of regenerative responses of neurons to injury. Our results show that FK+IBMX increased neurite length in the parent HT22 cell line, and this action was enhanced in Klf9 and Klf13 single KO cells, and was even greater in double KO cells. By contrast, the stimulatory effect of FK+IBMX on neurite outgrowth was blocked by simultaneous forced expression of Klf9 or Klf13 in parent HT22 cells. This effect on neurite outgrowth was confirmed in primary mouse hippocampal neurons, where electroporation of expression plasmids for Klf9 or Klf13 suppressed FK+IBMX-induced neurite extension compared with empty vector-transfected cells. Analysis of RNA-seq data obtained from HT22 cells following 8 hr of induced Klf9 or Klf13 expression showed that both proteins impact the cAMP signaling pathway. Using transfection-reporter assays and chromatin immunoprecipitation, we confirmed that several genes in this pathway are direct targets of both KLFs. Our findings suggest that KLF9 and KLF13 may cooperate to maintain the differentiated state of mammalian neurons and thereby block regeneration, in part, by repressing the cAMP signaling pathway.

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