Search

Hepatic gluconeogenesis is crucial for maintaining blood glucose during starvation, and a major contributor for hyperglycemia. Cellular redox state is related to mitochondrial biology and regulates conversion of specific metabolites to glucose. General control of amino acid synthesis 5 (GCN5) like-1 (GCN5L1) is a mitochondria-enriched protein which modulates glucose and amino acid metabolism. Here we show a new regulatory mode of GCN5L1 on gluconeogenesis using lactate and glycerol. We observed GCN5L1 deletion dramatically inhibited glucose production derived from glycerol and lactate, due to increased cytosolic redox state. The underlying mechanism is that GCN5L1 directly binds to the key component of mitochondrial shuttle glycerol phosphate dehydrogenase 2 (GPD2) and modulates its activity. These results have significant implications for understanding the physiological role and regulatory mechanism of mitochondrial shuttle in diabetes development and provide a novel therapeutic potential for diabetes.

Background. The aim of this study was to systematically evaluate the relationship between the expression of m6A RNA methylation regulators and prognosis in HCC. Methods. We compared the expression of m6A methylation modulators and PD-L1 between HCC and normal in TCGA database. HCC samples were divided into two subtypes by consensus clustering of data from m6A RNA methylation regulators. The differences in PD-L1, immune infiltration, and prognosis between the two subtypes were further compared. The LASSO regression was used to build a risk score for m6A modulators. In addition, we identified miRNAs that regulate m6A regulators. Results. We found that fourteen m6A regulatory genes were significantly differentially expressed between HCC and normal. HCC samples were divided into two clusters. Of these, there are higher PD-L1 expression and poorer overall survival (OS) in cluster 1. There was a significant difference in immune cell infiltration between cluster 1 and cluster 2. Through the LASSO model, we obtained 12 m6A methylation regulators to construct a prognostic risk score. Compared with patients with a high-risk score, patients with a low-risk score had upregulated PD-L1 expression and worse prognosis. There was a significant correlation between risk score and tumor-infiltrating immune cells. Finally, we found that miR-142 may be the important regulator for m6A RNA methylation in HCC. Conclusion. Our results suggest that m6A RNA methylation modulators may affect the prognosis through PD-L1 and immune cell infiltration in HCC patients. In addition, the two clusters may be beneficial for prognostic stratification and improving immunotherapeutic efficacy.

A well with a malfunctioning tubing retrievable sub surface safety valve (TRSSSV) was shut in until a lock-out operation could be undertaken, one which would secure the valve in a fully open position, enabling subsequent intervention programs to be carried out and the well put safely back on production. The TRSSSV design utilized a flapper valve with a power spring mechanism which forces the valve to a normally closed position. Control to the flapper had been lost as the hydraulic communication had been cut off. Repeated attempts to lock open the valve using the conventional lock out tool were unsuccessful, with its flapper returning to the closed position over time. The innovative solution presented in this paper was to engineer a simultaneously operated dual stroker electric line toolstring assembly, one leveraging several technology elements and executing several steps in a single run operation: (1) to position the work string correctly prior to engaging with the TRSSSV flow tube, (2) to operate the upper stroker to provide the axial force and stroke distance required to push the flow tube down to fully open the TRSSSV and hold it there until "locked", and (3) to simultaneously operate the lower stroker with expander adapter and dimple tool, to deform the valve flow tube and integral lock out sleeve when in a precise and predetermined position and in doing so permanently locking the valve in the open position. Carrying this out as a single trip operation would ensure the dimpling occurred only with the flow tube in the exact required "valve open" position. Individual communication & control and power sharing of both strokers was maintained throughout the operation using two surface computers in a master/slave configuration enabling a simultaneous coordinated operation. A NOGO sleeve was incorporated into the toolstring which aided precise depth correlation and space-out. Unhindered access for the subsequent intervention runs was ensured by using an eight arm multi-dimple device to prevent any ovalization of the flow tube during deformation. Force and distance limits for each stroker were set accordingly to ensure precise positioning during all phases of the operation such that no inadvertent forces would be applied to the TRSSSV. The job was executed following thorough pre-job design and verification tests. The pre-determined stroke force and distance requirements of the upper stroker to shift the TRSSSV into the open position, and those required from the lower stroker to expand the dimple tool and deform the flow tube to the pre-requisite extent, were applied and measured in real time. Some initial electric line runs were also carried out as part of the overall operation, namely a broach and a brush for cleaning possible scale accumulation. Following the successful lockout, the required diagnostic logging was completed, a straddle deployed to hold a wireline retrievable subsurface safety valve, and the well brought back into production.

BACKGROUND AND AIMS The regenerative capacity of the liver plays a protective role against hepatotoxins and impaired regeneration exacerbates liver dysfunction in nonalcoholic fatty liver disease (NAFLD). Mitochondrial bioenergetic and -synthetic functions are important contributory factors in hepatic regeneration, and the control of mitochondrial protein acetylation is implicated in the mitochondrial susceptibility to liver stressors. Here, we evaluated the role of general control of amino acid synthesis 5 like 1 (GCN5L1), a mediator of mitochondrial metabolism and acetylation, in modulating murine liver regeneration (LR) in response to acute CCl4 -induced hepatotoxicity. APPROACH AND RESULTS Initial metabolomic screening found that liver GCN5L1 knockout (LKO) mice have augmented glutaminolysis. Absence of GCN5L1 modified enzyme activity of liver-enriched glutaminase enzyme (glutaminase 2; GLS2), and GCN5L1 levels modulated GLS2 oligomerization and acetylation. This metabolic remodeling resulted in the elevation of α-ketoglutarate levels, which are known to activate mammalian target of rapamycin complex 1 (mTORC1). This signaling pathway was induced with increased phosphorylation of S6 kinase in LKO hepatocytes, and inhibition of glutaminolysis reversed aberrant mTORC1 signaling. At the same time, glutaminolysis, activity of GLS2, and activation of mTORC1 signaling were reversed by the genetic reintroduction of the mitochondrial isoform of GCN5L1 into LKO primary hepatocytes. Finally, LKO mice had a more robust regenerative capacity in response to CCl4 hepatoxicity, and this response was blunted by both the mTORC1 inhibitor, rapamycin, and by pharmacological blunting of glutaminolysis. CONCLUSIONS These data point to a central role of glutaminolysis in modulating the regenerative capacity in the liver. Furthermore, inhibition of mitochondrial GCN5L1 to augment LR may be a useful strategy in disease states linked to hepatotoxicity.

In mice, time of day strongly influences lethality in response to LPS, with survival greatest at the beginning compared to the end of the light cycle. Here we show that feeding, rather than light, controls time-of-day dependent LPS sensitivity. Mortality following LPS administration is independent of cytokine production and the clock regulator BMAL1 expressed in myeloid cells. In contrast, deletion of BMAL1 in hepatocytes globally disrupts the transcriptional response to the feeding cycle in the liver and results in constitutively high LPS sensitivity. Using RNAseq and functional validation studies we identify hepatic farnesoid X receptor (FXR) signalling as a BMAL1 and feeding-dependent regulator of LPS susceptibility. These results show that hepatocyte-intrinsic BMAL1 and FXR signalling integrate nutritional cues to regulate survival in response to innate immune stimuli. Understanding hepatic molecular programmes operational in response to these cues could identify novel pathways for targeting to enhance endotoxemia resistance., NIAMS. S.S.G. was supported by the NIH-Wellcome

Ethnopharmacological relevance : Huyang Yangkun Formula(HYF) is a traditional Chinese medicine formula based on the traditional theory of Yin and Yang. It could consolidate the Qi of Yin and Yang, adjust the balance of Qi and blood. It has shown clinical efficacy for patients with Premature Ovarian Insufficiency(POI). Aim of the study Aim to access the effect of Huyang Yangkun formula (HYF) on premature ovarian insufficiency rat model and explores the mechanism related to aquaporins(AQPs) and apoptosis. Materials and methods Female SD rats were injected with 4-vinylcyclonhexenediepoxide(VCD, 160 mg/kg/day) for 15 days. Then, HYF (0.297 g/kg)/estradiol valerate (0.1 mg/kg) was administered for 105 days in the HYF/estradiol valerate treatment(EVT) group. Serum AMH, FSH and E2 were detected by ELISA, and the developing follicles were counted in each group.The TUNEL assay was used to detect positive apoptotic signals. IHC and western blots were used to verify differentially expressed AQPs and apoptosis-related regulators potentially associated with HYF. Results Total follicles were increased significantly in the HYF group. Serum AMH was increased in the HYF group compared with MOD group. Serum FSH and E2 showed no obvious difference between HYF group and MOD group. Apoptosis occurred in POI model was proved by TUNEL and Caspase3/9 and HYF could rescue this apoptosis, besides the anti-apoptotic effect may be better than EVT. Distribution of AQPs in rat ovaries based on developmental stages of follicle was observed, and AQP8 was obviously expressed in the developing follicles and corpus luteum, particularly in granulosa cells. Upregulation of AQP8 in the MOD group and downregulation by HYF were observed. BCL-XL was significantly upregulated in the HYF group and EVT group; BCL-2 was upregulated in the HYF group with no statistical difference; MCL-1 was downregulated in the HYF group. BAX and BIM were significantly upregulated in the MOD group. The ratio of BCL-2/BAX and BCL-XL/BAX were decreased in the MOD group, and BCL-XL/BAX was increased in the HYF group and EVT group. Conclusion This study evaluated the treatment effect of HYF on POI in rats. It showed that HYF could promote the follicles development by regulating AQP8/Bcl-2 family-related mitochondrial apoptosis, which provides basic evidence for TCM as an alternative therapy for POI.

Premature ovarian insufficiency (POI) is a common female endocrine disease that is closely linked to ovarian function. Danggui Buxue Tang (DBT) is a classic prescription of traditional Chinese medicine that is helpful for rescuing ovarian function. However, the mechanism by which DBT rescues ovarian function remains unclear. This study explored the molecular mechanism of DBT with respect to apoptosis and related signals in ovarian cells. The quality control of DBT was performed by HPLC. After DBT intervention in the POI rat model, serum AMH/FSH/LH/E2 levels were detected by ELISA, follicles at various developmental stages were observed by HE staining, apoptosis was detected by TUNEL, and the expression profiles of Bcl-2 family proteins and key proteins in the Jak2/Foxo3a signaling pathway were evaluated by western blot. The results demonstrated that DBT could encourage the development of primary/secondary/antral follicles and increase the secretion of AMH. Moreover, DBT might inhibit Foxo3a by upregulating Jak2, thereby mediating Bcl-2 family activities and inhibiting apoptosis in ovarian cells. In conclusion, DBT promotes follicular development and rescues ovarian function by regulating Bcl-2 family proteins to inhibit cell apoptosis, which could be related to the Jak2/Foxo3a signaling pathway.

Background The aim of this study was to systematically evaluate the relationship between the expression of m6A RNA methylation regulators and prognosis in HCC. Methods We compared the expression of m6A methylation modulators and PD-L1 between HCC and normal in TCGA database. HCC samples were divided into two subtypes by consensus clustering of data from m6A RNA methylation regulators. The differences in PD-L1, immune infiltration, and prognosis between the two subtypes were further compared. The LASSO regression was used to build a risk score for m6A modulators. In addition, we identified miRNAs that regulate m6A regulators. Results We found that fourteen m6A regulatory genes were significantly differentially expressed between HCC and normal. HCC samples were divided into two clusters. Of these, there are higher PD-L1 expression and poorer overall survival (OS) in cluster 1. There was a significant difference in immune cell infiltration between cluster 1 and cluster 2. Through the LASSO model, we obtained 12 m6A methylation regulators to construct a prognostic risk score. Compared with patients with a high-risk score, patients with a low-risk score had upregulated PD-L1 expression and worse prognosis. There was a significant correlation between risk score and tumor-infiltrating immune cells. Finally, we found that miR-142 may be the important regulator for m6A RNA methylation in HCC. Conclusion Our results suggest that m6A RNA methylation modulators may affect the prognosis through PD-L1 and immune cell infiltration in HCC patients. In addition, the two clusters may be beneficial for prognostic stratification and improving immunotherapeutic efficacy.

Glucagon, a hormone released from pancreatic alpha-cells, plays a key role in maintaining proper glucose homeostasis and has been implicated in the pathophysiology of diabetes. In vitro studies suggest that intra-islet glucagon can modulate the function of pancreatic beta-cells. However, because of the lack of suitable experimental tools, the in vivo physiological role of this intra-islet cross-talk has remained elusive. To address this issue, we generated a novel mouse model that selectively expressed an inhibitory designer G protein-coupled receptor (Gi DREADD) in α-cells only. Drug-induced activation of this inhibitory designer receptor almost completely shut off glucagon secretion in vivo, resulting in significantly impaired insulin secretion, hyperglycemia, and glucose intolerance. Additional studies with mouse and human islets indicated that intra-islet glucagon stimulates insulin release primarily by activating β-cell GLP-1 receptors. These new findings strongly suggest that intra-islet glucagon signaling is essential for maintaining proper glucose homeostasis in vivo. Our work may pave the way toward the development of novel classes of antidiabetic drugs that act by modulating intra-islet cross-talk between α- and β-cells.

The wide application of oncolytic adenovirus presents a novel therapeutic strategy for breast cancer gene therapy. Application of adenovirus alone achieves little curative effects on breast cancer. In addition, it is worth exploring the synergistic anti-tumor effect by inserting immunomodulatory factor in oncolytic adenovirus genome. By taking the advantage of the highly proliferative property of breast cancer, a novel recombinant adenovirus which could selectively kill tumor cells is established under an E2F-1 promoter. Also by carrying human Interleukin-15 (IL-15) gene, the oncolytic adenovirus exhibits an immunomodulatory effect. The present study proved that the novel oncolytic virus (SG400-E2F/IL-15) exhibits an enhanced anti-tumor activity both in vitro and in vivo, representing an experimental basis for breast cancer “virus-gene” therapy.

General control of amino acid synthesis 5 like 1 (GCN5L1) was named due to its loose sequence alignment to GCN5, a catalytic subunit of numerous histone N-acetyltransferase complexes. Further studies show that GCN5L1 has mitochondrial and cytosolic isoforms, although functional-domain sequence alignment and experimental studies show that GCN5L1 itself does not possess intrinsic acetyltransferase activity. Nevertheless, GCN5L1 does support protein acetylation in the mitochondria and cytosol and functions as a subunit of numerous intracellular multiprotein complexes that control intracellular vacuolar organelle positioning and function. The majority of GCN5L1 studies have focused on distinct intracellular functions and in this review, we summarize these findings as well as postulate what may be common features of the diverse phenotypes linked to GCN5L1.

The first-order cross correlation and corresponding applications in the passive imaging are deeply studied by Garnier and Papanicolaou in their pioneer works. In this paper, the results of the first-order cross correlation are generalized to the second-order cross correlation. The second-order cross correlation is proven to be a statistically stable quantity, with respective to the random ambient noise sources. Specially, with proper time scales, the stochastic fluctuation for the second-order cross correlation converges much faster than the first-order one. Indeed, the convergent rate is of order , with 0 < α < 1. Besides, by using the stationary phase method in both homogeneous and scattering medium, similar behaviors of the singular components for the second-order cross correlation are obtained. Finally, two imaging methods are proposed to search for a target point reflector: One method is based on the imaging function, and has a better signal-to-noise rate; Another method is based on the geometric property, and can improve the bad range resolution of the imaging results.

The mitochondrial enriched GCN5-like 1 (GCN5L1) protein has been shown to modulate mitochondrial protein acetylation, mitochondrial content and mitochondrial retrograde signaling. Here we show that hepatic GCN5L1 ablation reduces fasting glucose levels and blunts hepatic gluconeogenesis without affecting systemic glucose tolerance. PEPCK and G6Pase transcript levels are downregulated in hepatocytes from GCN5L1 liver specific knockout mice and their upstream regulator, FoxO1 protein levels are decreased via proteasome-dependent degradation and via reactive oxygen species mediated ERK-1/2 phosphorylation. ERK inhibition restores FoxO1, gluconeogenic enzyme expression and glucose production. Reconstitution of mitochondrial-targeted GCN5L1 blunts mitochondrial ROS, ERK activation and increases FoxO1, gluconeogenic enzyme expression and hepatocyte glucose production. We suggest that mitochondrial GCN5L1 modulates post-translational control of FoxO1, regulates gluconeogenesis and controls metabolic pathways via mitochondrial ROS mediated ERK activation. Exploring mechanisms underpinning GCN5L1 mediated ROS signaling may expand our understanding of the role of mitochondria in gluconeogenesis control. Disclosure L. Wang: None.

Although GCN5L1 (also known as BLOC1S1) facilitates mitochondrial protein acetylation and controls endosomal-lysosomal trafficking, the mechanisms underpinning these disparate effects are unclear. As microtubule acetylation modulates endosome-lysosome trafficking, we reasoned that exploring the role of GCN5L1 in this biology may enhance our understanding of GCN5L1-mediated protein acetylation. We show that α-tubulin acetylation is reduced in GCN5L1-knockout hepatocytes and restored by GCN5L1 reconstitution. Furthermore, GCN5L1 binds to the α-tubulin acetyltransferase αTAT1, and GCN5L1-mediated α-tubulin acetylation is dependent on αTAT1. Given that cytosolic GCN5L1 has been identified as a component of numerous multiprotein complexes, we explored whether novel interacting partners contribute to this regulation. We identify RanBP2 as a novel interacting partner of GCN5L1 and αTAT1. Genetic silencing of RanBP2 phenocopies GCN5L1 depletion by reducing α-tubulin acetylation, and we find that RanBP2 possesses a tubulin-binding domain, which recruits GCN5L1 to α-tubulin. Finally, we find that genetic depletion of GCN5L1 promotes perinuclear lysosome accumulation and histone deacetylase inhibition partially restores lysosomal positioning. We conclude that the interactions of GCN5L1, RanBP2 and αTAT1 function in concert to control α-tubulin acetylation and may contribute towards the regulation of cellular lysosome positioning. This article has an associated First Person interview with the first author of the paper.

General control of amino acid synthesis 5 (GCN5) like-1 (GCN5L1) was identified as a novel gene with sequence homology to the histone acetyltransferase Gcn5. Subsequent protein-interaction studies identified GCN5L1 as a subunit of the multiprotein lysosome biogenesis complex, resulting in an alternative designation as biogenesis of lysosome-related organelle complex 1 subunit 1 (BLOS1 or BLOC1S1). Despite the distinct nomenclatures, GCN5L1/BLOS1 has been shown to play crucial roles in mitochondria, endosomes, lysosomes, and synaptic vesicle precursors (SVPs). GCN5L1/BLOS1 controls mitochondrial protein acetylation, modulates metabolic pathways, and orchestrates retrograde mitochondria-to-nucleus signaling. It also contributes to endosome–lysosome and vesicle trafficking and to endolysosomal function. Here we discuss the intracellular roles of GCN5L1/BLOS1 in the hope of linking mitochondria-centric effects to cytosolic vesicle biology.

The relationship between the single-nucleotide polymorphism (SNP) of ERBB4 gene in the microRNA binding site and the susceptibility of endometrial carcinoma was investigated. A total of 1671 patients with endometrial carcinoma and 1796 healthy controls were enrolled in the study. Genotypes of the ERBB4 gene in the microRNA binding sites at rs1595066 and rs16845990 were then determined using the TaqMan SNP method. The endometrial carcinoma patients and healthy controls showed significant differences in three ERBB4 gene genotypes in the microRNA binding site at rs1595066 (P = 0.044), whereas no difference was observed at the rs16845990 site (P = 0.313). Carriers of the AG and AA genotypes at the rs1595066 site showed lower risk of endometrial carcinoma than the carriers of the GG genotype [odds ratio (OR) = 0.82 and 95 % confidence interval (CI) = 0.70–0.94, and OR = 0.74 and 95 % CI = 0.56–0.94, respectively]. Stratified analysis showed that this protective effect was significant in subjects older than 50 years and those without a history of benign endometrial disease or a family history of cancer. The polymorphism of rs1595066 G > A in the microRNA binding site of the ERBB4 gene is possibly associated with the reduction of endometrial carcinoma risk.

We present a second order accurate numerical scheme for a nonlinear hyperbolic equation with an exponential nonlinear term. The solution to such an equation is proven to have a conservative nonlinear energy. Due to the special nature of the nonlinear term, the positivity is proven to be preserved under a periodic boundary condition for the solution. For the numerical scheme, a highly nonlinear fractional term is involved, for the theoretical justification of the energy stability. We propose a linear iteration algorithm to solve this nonlinear numerical scheme. A theoretical analysis shows a contraction mapping property of such a linear iteration under a trivial constraint for the time step. We also provide a detailed convergence analysis for the second order scheme, in the ? ∞ ( 0 , T ; ? ∞ ) norm. Such an error estimate in the maximum norm can be obtained by performing a higher order consistency analysis using asymptotic expansions for the numerical solution. As a result, instead of the standard comparison between the exact and numerical solutions, an error estimate between the numerical solution and the constructed approximate solution yields an O ( Δ t 3 + h 4 ) convergence in ? ∞ ( 0 , T ; ? 2 ) norm, which leads to the necessary ? ∞ error estimate using the inverse inequality, under a standard constraint Δ t ? C h . A numerical accuracy check is given and some numerical simulation results are also presented.

The mitochondrial enriched GCN5-like 1 (GCN5L1) protein has been shown to modulate mitochondrial protein acetylation, mitochondrial content and mitochondrial retrograde signaling. Here we show that hepatic GCN5L1 ablation reduces fasting glucose levels and blunts hepatic gluconeogenesis without affecting systemic glucose tolerance. PEPCK and G6Pase transcript levels are downregulated in hepatocytes from GCN5L1 liver specific knockout mice and their upstream regulator, FoxO1 protein levels are decreased via proteasome-dependent degradation and via reactive oxygen species mediated ERK-1/2 phosphorylation. ERK inhibition restores FoxO1, gluconeogenic enzyme expression and glucose production. Reconstitution of mitochondrial-targeted GCN5L1 blunts mitochondrial ROS, ERK activation and increases FoxO1, gluconeogenic enzyme expression and hepatocyte glucose production. We suggest that mitochondrial GCN5L1 modulates post-translational control of FoxO1, regulates gluconeogenesis and controls metabolic pathways via mitochondrial ROS mediated ERK activation. Exploring mechanisms underpinning GCN5L1 mediated ROS signaling may expand our understanding of the role of mitochondria in gluconeogenesis control., Hepatic gluconeogenesis is tightly regulated at transcriptional level and is essential for survival during prolonged fasting. Here Wang et al. show that the mitochondrial enriched GCN5-like 1 protein controls hepatic glucose production by regulating FoxO1 protein levels via proteasome-dependent degradation and, in turn, gluconeogenic gene expression.

Diet-induced obesity is commonly associated with leptin resistance, and attenuated leptin signaling contributes to the progression of obesity. PAQR3 is a member of the progesterone and AdipoQ receptor (PAQR) family with close homology to adiponectin receptors. We hypothesized that PAQR3 is implicated in the regulation of obesity and energy homeostasis. To address this hypothesis, we fed Paqr3-deleted mice with high-fat diet (HFD), followed by analyses to evaluate obesity, hepatic steatosis, insulin resistance, metabolic rate, and leptin signaling. We found that mice with deletion of Paqr3 are resistant to HFD-induced obesity and hepatic steatosis, accompanied by improvement of insulin resistance and insulin signaling. Paqr3-deleted mice have an increased energy expenditure and physical activity. HFD-induced leptin resistance is reversed by Paqr3 ablation. Overexpression of PAQR3 reduces leptin signaling whereas deletion of Paqr3 enhances leptin signaling in the hypothalamus. In conclusion, this study reveals that PAQR3 has an important physiological function in modulating obesity, energy metabolism, and leptin signaling.

Objective— Progesterone and adipoQ receptor (PAQR) 10 and PAQR11 are 2 highly homologous genes involved in compartmentalized Ras signaling in the Golgi apparatus. The aim of this study was to investigate the physiological functions of PAQR10 and PAQR11. Methods and Results— We used zebrafish as a model system to analyze the potential function of PAQR10/PAQR11. The expression profiles of PAQR10 and PAQR11 in zebrafish embryos are overlapping in many areas, but only PAQR11 is expressed in the developing heart. Knockdown of PAQR11 but not PAQR10 in zebrafish embryos causes cardiac developmental defects, including dilation of cardiac chambers, abnormal heart looping, disruption of atrioventricular cushion formation, heart edema, and blood regurgitation. PAQR11 knockdown markedly reduces the number and proliferation rate of cardiomyocytes and alters the morphology of myocardial cells during early heart development. The cardiac defects caused by PAQR11 knockdown can be phenocopied by MEK inhibitors and a dominant negative Ras. Furthermore, constitutively active Ras and especially a Golgi-localized but not a plasma membrane–localized Ras are able to rescue the cardiac defects caused by PAQR11 knockdown. Conclusion— This study not only provides in vivo evidence that PAQR11 plays a critical role in heart morphogenesis but also pinpoints the importance of compartmentalized Ras signaling during development.

Background & Aims Interleukin-22 (IL-22) is a Th17-related cytokine within the IL-10 family and plays an important role in host defense and inflammatory responses in orchestration with other Th17 cytokines. IL-22 exerts its functions in non-immune cells as its functional receptor IL-22R1 is restricted in peripheral tissues but not in immune cells. It was recently found that IL-22 serves as a protective molecule to counteract the destructive nature of the T cell-mediated immune response to liver damage. However, it is currently unknown whether IL-22 has an effect on lipid metabolism in the liver. Methods In this study, we demonstrate that IL-22 alleviates hepatic steatosis induced by high fat diet (HFD). Results Administration of recombinant murine IL-22 (rmIL-22) was able to stimulate STAT3 phosphorylation in HepG2 cells and mouse liver. The activation of STAT3 by rmIL-22 was reduced by the over-expression of a dominant negative IL-22R1. Within hours after rmIL-22 treatment, the expression of lipogenesis-related genes including critical transcription factors and enzymes for lipid synthesis in the liver was significantly down-regulated. The levels of triglyceride and cholesterol in the liver were significantly reduced by long-term treatment of rmIL-22 in C57BL/6 and ob/ob mice fed with HFD. The HFD-induced increases of ALT and AST in ob/ob mice were ameliorated by rmIL-22 treatment. In addition, the expression of fatty acid synthase and TNF-α in the liver was decreased by long-term rmIL-22 administration. Conclusions Collectively, these data indicate that IL-22, in addition to its known functions in host defense and inflammation, has a protective role in HFD-induced hepatic steatosis via its regulation on lipid metabolism in the liver.

The nutrient sensing Gcn5-like 1 (Gcn5L1) protein is enriched in mitochondria and in the endoplasmic reticulum (ER), although its function in these distinct compartments has not been fully characte...

Liver glycogen metabolism plays an important role in glucose homeostasis. Glycogen synthesis is mainly regulated by glycogen synthase that is dephosphorylated and activated by protein phosphatase 1 (PP1) in combination with glycogen-targeting subunits or G subunits. There are seven G subunits (PPP1R3A to G) that control glycogenesis in different organs. PPP1R3G is a recently discovered G subunit whose expression is changed along the fasting-feeding cycle and is proposed to play a role in postprandial glucose homeostasis. In this study, we analyzed the physiological function of PPP1R3G using a mouse model with liver-specific overexpression of PPP1R3G. PPP1R3G overexpression increases hepatic glycogen accumulation, stimulates glycogen synthase activity, elevates fasting blood glucose level, and accelerates postprandial blood glucose clearance. In addition, the transgenic mice have a reduced fat composition, together with decreased hepatic triglyceride level. Fasting-induced hepatic steatosis is relieved by PPP1R3G overexpression. In addition, PPP1R3G overexpression is able to elevate glycogenesis in primary hepatocytes. The glycogen-binding domain is indispensable for the physiological activities of PPP1R3G on glucose metabolism and triglyceride accumulation in the liver. Cumulatively, these data indicate that PPP1R3G plays a critical role in postprandial glucose homeostasis and liver triglyceride metabolism via its regulation on hepatic glycogenesis.

Phosphoinositide 3-kinase (PI3K) mediates insulin actions by relaying signals from insulin receptors (IRs) to downstream targets. The p110α catalytic subunit of class IA PI3K is the primary insulin-responsive PI3K implicated in insulin signaling. We demonstrate here a new mode of spatial regulation for the p110α subunit of PI3K by PAQR3 that is exclusively localized in the Golgi apparatus. PAQR3 interacts with p110α, and the intracellular targeting of p110α to the Golgi apparatus is reduced by PAQR3 downregulation and increased by PAQR3 overexpression. Insulin-stimulated PI3K activity and phosphoinositide (3,4,5)-triphosphate production are enhanced by Paqr3 deletion and reduced by PAQR3 overexpression in hepatocytes. Deletion of Paqr3 enhances insulin-stimulated phosphorylation of AKT and glycogen synthase kinase 3β, but not phosphorylation of IR and IR substrate-1 (IRS-1), in hepatocytes, mouse liver, and skeletal muscle. Insulin-stimulated GLUT4 translocation to the plasma membrane and glucose uptake are enhanced by Paqr3 ablation. Furthermore, PAQR3 interacts with the domain of p110α involved in its binding with p85, the regulatory subunit of PI3K. Overexpression of PAQR3 dose-dependently reduces the interaction of p85α with p110α. Thus, PAQR3 negatively regulates insulin signaling by shunting cytosolic p110α to the Golgi apparatus while competing with p85 subunit in forming a PI3K complex with p110α.

PAQR3 is a member of the progestin and adipoQ receptor (PAQR) family and was recently characterized as a spatial regulator that negatively modulates Ras/Raf/MEK/ERK signaling cascade. However, little is known about the physiological functions of PAQR3 in the tumorigenesis of colorectal cancers. The function of PAQR3 in colorectal cancer development in mice was analyzed by crossing Paqr3-depleted mice with Apc(Min/+) mice that have a germline mutation of the gene-encoding tumor suppressor adenomatous polyposis coli (APC). The survival time and tumor area in the small intestine of the Apc(Min/+) mice was significantly aggravated by Paqr3 deletion. The cell proliferation rate, anchorage-independent growth, EGF-stimulated ERK phosphorylation and EGF-induced nuclear accumulation of beta-catenin were inhibited by PAQR3 overexpression and enhanced by PAQR3 knockdown in SW-480 colorectal cancer cells. In humans, the expression level of PAQR3 was significantly decreased in colorectal cancer samples in comparison with adjacent normal tissues. In addition, the expression level of PAQR3 was inversely associated with tumor grade in the colorectal cancer samples. Collectively, our data reveal for the first time that PAQR3 has a tumor suppressor activity in the development of colorectal cancers.

Background: TGF-beta has been known to play an important role in various liver diseases including fibrosis and alcohol-induced fatty liver. Smad7 is an intracellular negative regulator of TGF-b signaling. It is currently unclear whether endogenous Smad7 has an effect on liver function and alcoholic liver damage. Methodology/Principal Findings: We used Cre/loxP system by crossing Alb-Cre mice with Smad7(loxP/loxP) mice to generate liver-specific deletion of Smad7 with loss of the indispensable MH2 domain. Alcoholic liver injury was achieved by feeding mice with a liquid diet containing 5% ethanol for 6 weeks, followed by a single dose of ethanol gavage. Deletion of Smad7 in the liver was associated with increased Smad2/3 phosphorylation in the liver or upon TGF-b treatment in primary hepatocytes. The majority of mice with liver specific deletion of Smad7 (Smad7(liver-KO)) were viable and phenotypically normal, accompanied by only slight or no reduction of Smad7 expression in the liver. However, about 30% of Smad7(liver-KO) mice with high efficiency of Smad7 deletion had spontaneous liver dysfunction, demonstrated as low body weight, overall deterioration, and increased serum levels of AST and ALT. Degeneration and elevated apoptosis of liver cells were observed with these mice. TGF-b-induced epithelial to mesenchymal transition (EMT) was accelerated in Smad7-deleted primary hepatocytes. In addition, alcohol-induced liver injury and steatosis were profoundly aggravated in Smad7 deficient mice, associated with upregulation of critical genes involved in lipogenesis and inflammation. Furthermore, alcohol-induced ADH1 expression was significantly abrogated by Smad7 deletion in hepatocytes. Conclusion/Significance: In this study, we provided in vivo evidence revealing that endogenous Smad7 plays an important role in liver function and alcohol-induced liver injury.

Interleukin 22 (IL-22) is a T-cell secreted cytokine that modulates inflammatory response in nonhematopoietic tissues such as epithelium and liver. The function of IL-22 in adipose tissue is currently unknown. We generated a transgenic mouse model with overexpression of IL-22 specifically in adipose tissue. The IL-22 transgenic mice had no apparent changes in obesity and insulin resistance after feeding with high fat diet (HFD). Unexpectedly, all the IL-22 transgenic mice fed with HFD for four months developed spontaneous tumors in epididymal adipose tissue. Histological analysis indicated that the tumors were well-differentiated liposarcomas with infiltration of inflammatory cells. IL-22 overexpression promotes production of inflammatory cytokines such as IL-1β and IL-10 and stimulates ERK phosphorylation in adipose tissue. Furthermore, IL-22 treatment in differentiated 3T3-L1 adipocytes could induce IL-1β and IL-10 expression, together with stimulation of ERK phosphorylation. Taken together, our study not only established a novel mouse model with spontaneous liposarcoma, but also revealed that IL-22 overexpression may collaborate with diet-induced obesity to impact on tumor development in mouse.

Matrix metalloproteinase 2 (MMP-2) and membrane type 1 matrix metalloproteinase (MT1-MMP) have been identified as important participants in tumor invasion, metastasis, and angiogenesis. Membrane type 1 matrix metalloproteinase has also been recognized as a major activator of MMP-2. The purpose of this study was to investigate epidermal growth factor (EGF) mediating signal pathways in the regulation of MMP-2 and MT1-MMP in SiHa cells, a cervical cancer cell line. We showed here that EGF induced the expression of MT1-MMP and inhibited the expression of MMP-2 at both the mRNA and protein levels. Membrane type 1 matrix metalloproteinase induction was blocked by mitogen-activated protein kinase or extracellular signal-regulated kinase inhibitors PD98059 and U0126 but not by phosphatidylinositol-3 kinase (PI3-K) inhibitors LY294002 and wortmannin. Interestingly, the mitogen-activated protein kinase or extracellular signal-regulated kinase inhibitors PD98059 and U0126 actually increased MMP-2 mRNA and protein synthesis, whereas the PI3-K inhibitors LY294002 and wortmannin further suppressed the expression of MMP-2. Our results suggest that EGF receptor up-regulated the expression of MT1-MMP and down-regulated the synthesis of MMP-2 through the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway while concomitantly transmitting a mild positive regulatory signal to the expression of MMP-2 via the PI3-K/AKT pathway in SiHa cells. Furthermore, we found that EGF elevated the activity of MMP-2 in culture media.

Upon activation, TGF-β type I receptor (TβRI) undergoes active ubiquitination via recruitment of E3 ligases to the receptor complex by Smad7. However, how ubiquitination of TβRI is coupled to intracellular trafficking, and protein degradation remains unclear. We report here that Tollip, an adaptor protein that contains both ubiquitin-associated domains and endosome-targeting domain, plays an important role in modulating trafficking and degradation of TβRI. Tollip was previously demonstrated to possess a functional role in modulating the signaling of interleukin-1 and Toll-like receptors. We identify here that Tollip interacts with Smad7, a major modulatory protein involved in the negative regulation of TGF-β signaling. Overexpression of Tollip antagonizes TGF-β-stimulated transcriptional response, Smad2 phosphorylation, and epithelial-mesenchymal transition. Tollip also interacts with ubiquitinated TβRI, and such interaction requires ubiquitin-associated domains of Tollip. The interaction and intracellular colocalization of Tollip with TβRI is enhanced by Smad7. Overexpression of Tollip accelerates protein degradation of activated TβRI. In addition, Tollip alters subcellular compartmentalization and endosomal trafficking of activated TβRI. Collectively, our studies reveal that Tollip cooperates with Smad7 to modulate intracellular trafficking and degradation of ubiquitinated TβRI, whereby negatively regulates TGF-β signaling pathway.