JAK2-STAT5 Signaling Pathway Research Articles

Effect of different cooking methods on saponin content and hematopoietic effects of Panax notoginseng-steamed chicken on mice.

Panax notoginseng-steamed chicken (PNSC) is a medicinal food with ethnic characteristics developed by the Miao ethnic group in the southeast of Yunnan Province, China. PNSC has been eaten for hundreds of years, and its tonic effect has been widely recognized by the people. However, its cooking conditions and scientific connotation of its effect of toning blood and supplementing deficiency are also lack of in-depth analysis. To optimize the cooking conditions of Panax notoginseng-steamed chicken (PNSC) and to explore its anemia-improving effects. The ratio of P. notoginseng (PN) to chicken and the steaming time were systematically altered, and the PNSC cooking conditions was optimized with the response surface method. By establishing animal models of postpartum blood-deficiency anemia, acute hemorrhagic anemia and myelosuppressive anemia, the blood replenishing effect of PNSC was explored, and the blood replenishing mechanism of PNSC on myelosuppressive anemia was revealed by immunoblotting analyses and histopathological sectioning. The optimal processing conditions included a ratio of chicken to P. notoginseng of 100:5 and a steaming time of 5.5 h. The amounts of P. notoginseng polysaccharides (PNPS), total protein and blood-enriching P. notoginseng saponins were 44.3 mg/g, 2.48% and 2.04%, respectively. Freeze-dried powder of P. notoginseng steamed chicken soup (FPSC) was found to promote the recovery of routine blood factors and organ indexes in the three models of anemia and to activate the JAK2-STAT5 signaling pathway, induce phosphorylation of JAK2 and STAT5 and normalize the secretion of hematopoietic regulators EPO, IL-3, and TNF-α. FPSC improves the symptoms of anemia in mice, and it plays a role in tonifying blood by activating the JAK2-STAT5 signaling pathway and altering the expression of hematopoiesis-related factors.

MiR-190a regulates milk protein biosynthesis through the mTOR and JAK2–STAT5 signaling pathways by targeting PTHLH in buffalo mammary epithelial cells

Milk protein is a key quality indicator of milk, so elucidating its synthesis mechanism has been the focus of research in recent years. Studies have shown that both miRNAs and mRNA genes play important roles in the regulation of milk protein synthesis. In this study, a total of 7 and 4073 differentially expressed miRNA and mRNA genes were identified between early and peak lactation, respectively. Overexpression and knockdown experiments of parathyroid hormone like hormone gene (PTHLH) gene showed that it can promote milk protein synthesis in buffalo mammary epithelial cells (BuMECs) through mammalian target of rapamycin (mTOR) and janus kinase 2/signal transducer and activator of transcription 5 (JAK2–STAT5) signaling pathways, and the experiments treated with miR-190a mimic or inhibitor showed that miR-190a inhibited the expression of PTHLH gene. In addition, miR-190a inhibited milk protein synthesis by targeting PTHLH through mTOR and JAK2–STAT5 signaling pathways in BuMECs. Collectively, these findings reveal a novel miR-190a–PTHLH pathway that has a significant role in regulating milk protein synthesis.

CEBPA-Regulated Expression of SOCS1 Suppresses Milk Protein Synthesis through mTOR and JAK2-STAT5 Signaling Pathways in Buffalo Mammary Epithelial Cells

Milk protein content is a key quality indicator of milk, and therefore elucidating its synthesis mechanism has been the focus of research in recent years. Suppressor of cytokine signaling 1 (SOCS1) is an important inhibitor of cytokine signaling pathways that can inhibit milk protein synthesis in mice. However, it remains elusive whether SOCS1 plays roles in the milk protein synthesis in the buffalo mammary gland. In this study, we found that the mRNA and protein expression levels of SOCS1 in buffalo mammary tissue during the dry-off period was significantly lower than those during lactation. Overexpression and knockdown experiments of SOCS1 showed that it influenced the expression and phosphorylation of multiple key factors in the mTOR and JAK2-STAT5 signaling pathways in buffalo mammary epithelial cells (BuMECs). Consistently, intracellular milk protein content was significantly decreased in cells with SOCS1 overexpression, while it increased significantly in the cells with SOCS1 knockdown. The CCAAT/enhancer binding protein α (CEBPA) could enhance the mRNA and protein expression of SOCS1 and its promoter activity in BuMECs, but this effect was eliminated when CEBPA and NF-κB binding sites were deleted. Therefore, CEBPA was determined to promote SOCS1 transcription via the CEBPA and NF-κB binding sites located in the SOCS1 promoter. Our data indicate that buffalo SOCS1 plays a significant role in affecting milk protein synthesis through the mTOR and JAK2-STAT5 signaling pathways, and its expression is directly regulated by CEBPA. These results improve our understanding of the regulation mechanism of buffalo milk protein synthesis.

Molecular basis of JAK2 H608Y and H608N mutations in the pathology of acute myeloid leukemia

Risk-stratification of acute myeloid leukemia (AML) based on (cyto)genetic aberrations, including hotspot mutations, deletions and point mutations have evolved substantially in recent years. With the development of next-generation sequence technology, more and more novel mutations in the AML were identified. Thus, to unravel roles and mechanism of novel mutations would improve prognostic and predictive abilities. In this study, two novel germline JAK2 His608Tyr (H608Y) and His608Asn (H608N) mutations were identified and the molecular basis of these mutations in the leukemiagenesis of AML was elucidated. Our results indicated that JAK2 H608Y and H608N mutations disrupted the hydrogen bond between Q656 and H608 which reduced the JH2 domain's activity and abolished interactions between JH1 and JH2 domains, forced JAK2 into the active conformation, facilitated the entrance of substrates and thus caused JAK2 hyperactivation. Further studies suggested that JAK2 H608Y and H608N mutations enhanced the cell proliferation and inhibited the differentiation of Ba/F3 and MV4-11 cells via activating the JAK2-STAT5 signaling pathway. Moreover, rescue experiments demonstrated that mutations repaired the hydrogen bond between Q656 and H608 displayed opposite results. Thus, this study revealed the molecular basis of JAK2 H608Y and H608N mutations in the pathology of AML.

Alpha7 Nicotinic Acetylcholine Receptor Antagonists Prevent Meningitic Escherichia coli-Induced Blood-Brain Barrier Disruptions by Targeting the CISH/JAK2/STAT5b Axis.

Despite the availability of antibiotics over the last several decades, excessive antibiotic treatments for bacterial sepsis and meningitis (BSM) in children may result in several adverse outcomes. Hematogenous pathogens may directly induce permeability increases in human brain microvascular endothelial cells (HBMECs) and blood–brain barrier (BBB) dysfunctions. Our preliminary studies demonstrated that the alpha7 nicotinic acetylcholine receptor (α7nAChR) played an important role in the pathogenesis of BSM, accompanied by increasing cytokine-inducible SH2-containing protein (CISH) at the transcriptome level, but it has remained unclear how α7nAChR-CISH works mechanistically. The study aims to explore the underlying mechanism of α7nAChR and CISH during E. coli-induced BSM in vitro (HBMECs) and in vivo (α7nAChR-KO mouse). We found that in the stage of E. coli K1-induced BBB disruptions, α7nAChR functioned as the key regulator that affects the integrity of HBMECs by activating the JAK2–STAT5 signaling pathway, while CISH inhibited JAK2–STAT5 activation and exhibited protective effects against E. coli infection. Notably, we first validated that the expression of CISH could be regulated by α7nAChR in HBMECs. In addition, we determined the protective effects of MLA (methyllycaconitine citrate) and MEM (memantine hydrochloride) (functioning as α7nAChR antagonists) on infected HBMECs and suggested that the α7nAChR–CISH axis could explain the protective effects of the two small-molecule compounds on E. coli-induced HBMECs injuries and BBB disruptions. In conclusion, we dissected the α7nAChR/CISH/JAK2/STAT5 axis as critical for the pathogenesis of E. coli-induced brain microvascular leakage and BBB disruptions and provided novel evidence for the development of α7nAChR antagonists in the prevention of pediatric E. coli BSM.

Regulation of Sexually Dimorphic Expression of Major Urinary Proteins.

Male house mice excrete large amounts of protein in their urinary scent marks, mainly composed of Major Urinary Proteins (MUPs), and these lipocalins function as pheromones and pheromone carriers. Here, we review studies on sexually dimorphic MUP expression in house mice, including the proximate mechanisms controlling MUP gene expression and their adaptive functions. Males excrete 2 to 8 times more urinary protein than females, though there is enormous variation in gene expression across loci in both sexes. MUP expression is dynamically regulated depending upon a variety of factors. Males regulate MUP expression according to social status, whereas females do not, and males regulate expression depending upon health and condition. Male-biased MUP expression is regulated by pituitary secretion of growth hormone (GH), which binds receptors in the liver, activating the JAK2-STAT5 signaling pathway, chromatin accessibility, and MUP gene transcription. Pulsatile male GH secretion is feminized by several factors, including caloric restriction, microbiota depletion, and aging, which helps explain condition-dependent MUP expression. If MUP production has sex-specific fitness optima, then this should generate sexual antagonism over allelic expression (intra-locus sexual conflict) selectively favoring sexually dimorphic expression. MUPs influence the sexual attractiveness of male urinary odor and increased urinary protein excretion is correlated with the reproductive success of males but not females. This finding could explain the selective maintenance of sexually dimorphic MUP expression. Producing MUPs entails energetic costs, but increased excretion may reduce the net energetic costs and predation risks from male scent marking as well as prolong the release of chemical signals. MUPs may also provide physiological benefits, including regulating metabolic rate and toxin removal, which may have sex-specific effects on survival. A phylogenetic analysis on the origins of male-biased MUP gene expression in Mus musculus suggests that this sexual dimorphism evolved by increasing male MUP expression rather than reducing female expression.

Regulation of the JAK2-STAT5 Pathway by Signaling Molecules in the Mammary Gland.

Janus kinase 2 (JAK2) and signal transducers and activators of transcription 5 (STAT5) are involved in the proliferation, differentiation, and survival of mammary gland epithelial cells. Dysregulation of JAK2-STAT5 activity invariably leads to mammary gland developmental defects and/or diseases, including breast cancer. Proper functioning of the JAK2-STAT5 signaling pathway relies on crosstalk with other signaling pathways (synergistically or antagonistically), which leads to normal biological performance. This review highlights recent progress regarding the critical components of the JAK2-STAT5 pathway and its crosstalk with G-protein coupled receptor (GPCR) signaling, PI3K-Akt signaling, growth factors, inflammatory cytokines, hormone receptors, and cell adhesion.

Inhibition of the Activity of Cyclophilin A Impedes Prolactin Receptor-Mediated Signaling, Mammary Tumorigenesis, and Metastases

SummaryProlactin (PRL) and its receptor (PRLr) play important roles in the pathogenesis of breast cancer. Cyclophilin A (CypA) is a cis-trans peptidyl-prolyl isomerase (PPI) that is constitutively associated with the PRLr and facilitates the activation of the tyrosine kinase Jak2. Treatment with the non-immunosuppressive prolyl isomerase inhibitor NIM811 or CypA short hairpin RNA inhibited PRL-stimulated signaling, breast cancer cell growth, and migration. Transcriptomic analysis revealed that NIM811 inhibited two-thirds of the top 50 PRL-induced genes and a reduction in gene pathways associated with cancer cell signaling. In vivo treatment of NIM811 in a TNBC xenograft lessened primary tumor growth and induced central tumor necrosis. Deletion of CypA in the MMTV-PyMT mouse model demonstrated inhibition of tumorigenesis with significant reduction in lung and lymph node metastasis. The regulation of PRLr/Jak2-mediated biology by NIM811 demonstrates that a non-immunosuppressive prolyl isomerase inhibitor can function as a potential breast cancer therapeutic.

Characterization of growth hormone (GH) in Chinese soft-shelled turtle: Molecular identification, capability in activating GH receptor and tissue distribution

Growth hormone (GH) participates in many physiological processes through the activation of its membrane-anchored receptor (GHR) in vertebrates. Because of its pivotal role in regulating growth and development, a large number of studies examining GH-GHR have been conducted in mammals, birds and fish. However, whether a functional GH-GHR pair exists in the Chinese soft-shelled turtle (st-) has not been previously studied. Here, the full-length cDNA encoding GH was cloned from Chinese soft-shelled turtle (Trionyx sinensis) pituitary. The results revealed that it consisted of 784 bp and encoded a precursor of 217 amino acids. Furthermore, recombinant stGH was prepared and purified from Escherichia coli (E. coli) strain BL21. Using the 5×STAT5-Luciferase reporter system, we found that stGHR expressed in human hepatocellular carcinoma cells could be activated in a dose-dependent manner by recombinant stGH, thereby triggering the intracellular JAK2-STAT5 signaling pathway, suggesting stGH is a functional ligand for stGHR. Quantitative real-time PCR revealed that GH mRNA was predominantly and abundantly expressed in pituitary, while GHR exhibited ubiquitous expression in all tissues examined, including pituitary and liver. Collectively, our data indicate a conserved GH-GHR pair might function in reptiles including Chinese soft-shelled turtle, as that in mammals, birds and fishes.

High levels of fatty acids inhibit β-casein synthesis through suppression of the JAK2/STAT5 and mTOR signaling pathways in mammary epithelial cells of cows with clinical ketosis.

Ketosis is a metabolic disease of dairy cows often characterized by high concentrations of ketone bodies and fatty acids, but low milk protein and milk production. The Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) and the mechanistic target of rapamycin (mTOR) signaling pathways are central for the regulation of milk protein synthesis. The effect of high levels of fatty acids on these pathways and β-casein synthesis are unknown in dairy cows with clinical ketosis. Mammary gland tissue and blood samples were collected from healthy (n = 15) and clinically-ketotic (n = 15) cows. In addition, bovine mammary epithelial cells (BMEC) were treated with fatty acids, methionine (Met) or prolactin (PRL), respectively. In vivo, the serum concentration of fatty acids was greater (P > 0.05) and the percentage of milk protein (P > 0.05) was lower in cows with clinical ketosis. The JAK2-STAT5 and mTOR signaling pathways were inhibited and the abundance of β-casein was lower in mammary tissue of cows with clinical ketosis (P > 0.05). In vitro, high levels of fatty acids inhibited the JAK2-STAT5 and mTOR signaling pathways (P > 0.05) and further decreased the β-casein synthesis (P > 0.05) in BMEC. Methionine or PRL treatment, as positive regulators, activated the JAK2-STAT5 and mTOR signaling pathways to increase the β-casein synthesis. Importantly, the high concentration of fatty acids attenuated the positive effect of Met or PRL on mTOR, JAK2-STAT5 pathways and the abundance of β-casein (P > 0.05). Overall, these data indicate that the high concentrations of fatty acids that reach the mammary cells during clinical ketosis inhibit mTOR and JAK2-STAT5 signaling pathways, and further suppress β-casein synthesis.

Reducing PRLR expression and JAK2 activity results in an increase in BDNF expression and inhibits the apoptosis of CA3 hippocampal neurons in a chronic mild stress model of depression

Patients suffering from depression most commonly present with symptoms associated with the autonomic nervous system. Despite the satisfactory results achieved following treatment with vagus nerve stimulation and drug treatment, recurrence is a common occurrence in many patients. As described in numerous studies, prolactin receptor (PRLR) has been identified as an anxiolytic and anti-depressant factor in depression. However, the effect of PRLR on chronic mild stress (CMS)-induced depression remains to be thoroughly demonstrated. Therefore, the present study was conducted on the effect of PRLR gene on brain derived neurotrophic factor (BDNF) expression and hippocampal neuron apoptosis through the establishment of CMS-induced depression mouse models, with aims of providing a new and effective therapeutic option for depression. Microarray-based analysis was initially used to retrieve depression-related expression dataset and PRLR-related signaling pathway. Lentiviral vectors overexpressing PRLR or expressing PRLR-specific shRNA were used to up- or down-regulated the expression of PRLR in mice. Subsequently, the effects of PRLR on hippocampal neurons and pyramidal cells in CA1 and CA3 regions, and ultrastructure in hippocampal region were evaluated. Serum BDNF level and the positive rate of cleaved-Caspase-3 in hippocampal CA3 region were determined. Next, the regulatory mechanism by which PRLR gene silencing influences hippocampal neuron apoptosis via the JAK2-STAT5 signaling pathway was detected. PRLR gene was assumed to participate in the development of depression by regulating the JAK-STAT signaling pathway. Our results found that the mice with CMS-induced depression exhibited locomotion activity and anhedonia. In addition, a decrease in the number of pyramidal cells was observed in the hippocampus while that of apoptotic cells was increased. In addition, serum BDNF level was increased, and the expression of Caspase-3 and Bax in hippocampal neurons and the JAK2-STAT5 signaling pathway was decreased in response to PRLR silencing, along with increased expression of BDNF and Bcl-2. From the aforementioned findings, we concluded that PRLR gene silencing results in the inhibition of hippocampal neuron apoptosis and alleviation of CMS-induced depression by inactivating the JAK2-STAT5 signaling pathway and elevating BDNF expression, providing a new insight for the treatment of depression.

The inhibitor of interleukin-3 receptor protects against sepsis in a rat model of cecal ligation and puncture

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. There are multiple cytokines involved in the process of sepsis. As an important upstream cytokine in inflammation, Interleukin-3 (IL-3) plays a crucial role during sepsis, however, its exact role is unclear. The purpose of this study is to discuss the role of IL-3 and its receptor in cecal ligation and puncture (CLP)-induced sepsis in a rat model. The Cluster of Differentiation 123 (CD123, IL-3 receptor alpha chain, IL-3Rac) antibody (anti-CD123) was used to directly target IL-3′s receptor and alleviate the effect of IL-3 in the CLP + anti-CD123 group during the early stage of sepsis. CLP was performed in the CLP and CLP + anti-CD123 groups. The time points of observation included 12 h, 24 h, and 5d after the operation. The results showed that the rats in the CLP + anti-CD123 group had lower levels of lactate, serum tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), and Interleukin-6 (IL-6), and also exhibited a higher core temperature, mean arterial pressure (MAP), Oxygenation Index (PO2/FiO2), and end-tidal carbon dioxide (ETCO2) and serum Interleukin-10 (IL-10) levels after CLP than those in the CLP group. Additionally, administration of anti-CD123 led to a stable down-regulation of tyrosine phosphorylation of the IL-3 receptor, a decline in phosphorylation of the Janus kinase 2 (JAK2) protein, and the signal transduction and activation of transcription 5 (STAT5) proteins in lung tissues. Meanwhile, the study revealed that treatment of anti-CD123 can markedly attenuate histological damages in lung and kidney tissues, improve sublingual microcirculation, and prolong survival post sepsis. In conclusion, anti-CD123 reduces mortality and alleviates organ dysfunction by restraining the JAK2-STAT5 signaling pathway and reduces serum cytokines in the development of early sepsis in a rat model induced by CLP.

Dipeptide (Methionyl-Methionine) Transport and Its Effect on β-Casein Synthesis in Bovine Mammary Epithelial Cells

Background/Aims: The aim of this study was to investigate the transport properties and utilization of methionyl-methionine dipeptide (Met-Met) in β-casein (β-CN) synthesis in bovine mammary epithelial cells (BMECs). Methods: The transport properties were studied for the effects of time, pH, concentration, temperature and inhibitors using Met-Met-FITC in BMECs. BMECs were treated with different concentrations of Met-Met (0, 20, 40, 80, 120 and 160 µg/ml). In several experiments, the cells were treated with Janus kinase 2 (JAK2) inhibitor (tyrphostin AG-490, 50 µM) and mammalian target of rapamycin (mTOR) inhibitor (rapamycin, 100 ng/ml). Results: The uptake of Met-Met-FITC by BMECs was rapid during the first fifteen minutes and became saturated after 15 minutes. The transport of Met-Met-FITC in BMECs exhibited a Michaelis constant of 52.4 µM and maximum transport velocity of 14.8 pmol/min/mg protein. The uptake of Met-Met-FITC in BMECs was pH-dependent, peaked at pH 6.5 and was significantly inhibited by other peptides, including Met-Lys, Lys-Lys, Gly-Met, Gly-Leu and Met-Leu. Knocking down the peptide transporter 2 (PepT2) with small interference RNA markedly decreased Met-Met-FITC uptake. Met-Met concentration-dependently increased the PepT2 expression and β-CN synthesis in BMECs with an optimal concentration of 80 µg/ml. At 80 µg/ml, Met-Met also enhanced the cell viability and cyclin D1 expression and promoted cell cycle transition from G1 phase to S phase. In addition, 80 µg/ml Met-Met increased the mRNA abundance of JAK2 and signal transducer and activator of transcription 5 (STAT5) and enhanced the phosphorylation of JAK2, STAT5, mTOR, p70 ribosomal S6 kinase 1 and eukaryotic initiation factor 4E binding protein 1. The inhibition of JAK2 and mTOR significantly decreased Met-Met-induced increase in cell viability and β-CN synthesis in BMECs. Conclusion: Our data elucidated the properties of peptide transporter and its effect on β-CN synthesis in BMECs. Met-Met, taken up by PepT2, enhances cell proliferation and promotes β-CN synthesis by activating JAK2-STAT5 and mTOR signaling pathways in BMECs.

Suppressor of Cytokine Signaling 2 Negatively Regulates NK Cell Differentiation by Inhibiting JAK2 Activity

Suppressor of cytokine signaling (SOCS) proteins are negative regulators of cytokine responses. Although recent reports have shown regulatory roles for SOCS proteins in innate and adaptive immunity, their roles in natural killer (NK) cell development are largely unknown. Here, we show that SOCS2 is involved in NK cell development. SOCS2−/− mice showed a high frequency of NK cells in the bone marrow and spleen. Knockdown of SOCS2 was associated with enhanced differentiation of NK cells in vitro, and the transplantation of hematopoietic stem cells (HSCs) into congenic mice resulted in enhanced differentiation in SOCS2−/− HSCs. We found that SOCS2 could inhibit Janus kinase 2 (JAK2) activity and JAK2-STAT5 signaling pathways via direct interaction with JAK2. Furthermore, SOCS2−/− mice showed a reduction in lung metastases and an increase in survival following melanoma challenge. Overall, our findings suggest that SOCS2 negatively regulates the development of NK cells by inhibiting JAK2 activity via direct interaction.

Inhibitory effect of baicalin on allergic response in ovalbumin-induced allergic rhinitis guinea pigs and lipopolysaccharide-stimulated human mast cells.

Baicalin, a flavonoid compound purified from the dry roots of Scutellaria baicalensis Georgi, has generally been used for the treatment of various allergic diseases. However, there is little information about the anti-inflammatory effects of baicalin for allergic rhinitis. This study aims to investigate the anti-allergic effect of baicalin on allergic response in ovalbumin (OVA)-induced allergic rhinitis guinea pigs and lipopolysaccharide (LPS)-stimulated human mast cells. Using in vivo models, we evaluated the effect of baicalin on allergic rhinitis symptoms via recording the number of nasal rubs and sneezes. The levels of histamine, OVA-specific immunoglobulin E(IgE), eosinophil cationic protein (ECP) and inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA). The histological changes of nasal mucosa were observed by light microscope after HE staining. In vitro, the release of histamine and β-hexosaminidase of compound 48/80-induced human mast cells were measured by ELISA and PNP-NAG colorimetry, respectively. The productions of inflammatory cytokines of LPS-stimulated human mast cells were determined using ELISA. Western blot was used to test the protein expression of JAK2, p-JAK2, STAT5, p-STAT5, IKKβ, p-IKKβ, IκBα, p-IκBα and NF-κB (p65) of LPS-stimulated human mast cells. The oral administration of baicalin at doses of 50 and 200mg/kg improved allergic rhinitis symptoms and the histological changes of nasal mucosa and decreased the serum levels of histamine, ECP, interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α and OVA-specific IgE in OVA-induced allergic rhinitis guinea pigs. In vitro, baicalin suppressed the release of histamine and β-hexosaminidase in compound 48/80-induced human mast cells. In addition, baicalin also inhibited the productions of inflammatory cytokines such as IL-1β, IL-6, IL-8 and TNF-α and suppressed the phosphorylation of JAK2, STAT5, IKKβ, IκBα and the nuclear translocation of NF-κB (p65) subunit in LPS-stimulated human mast cells. These results suggest that baicalin can effectively prevent allergic response in OVA-induced allergic rhinitis guinea pigs and inhibit inflammatory response via blocking JAK2-STAT5 and NF-κB signaling pathways in LPS-stimulated human mast cells. Considered together,the results show that baicalin may be a useful drug in the treatment of allergic rhinitis.

Effect of chronic administration of growth hormone on JAK2-STAT5 signaling pathway in the liver

Effect of chronic administration of growth hormone on JAK2-STAT5 signaling pathway in the liver

Scribble is required for pregnancy-induced alveologenesis in the adult mammary gland.

The cell polarity protein scribble (SCRIB) is a crucial regulator of polarization, cell migration and tumorigenesis. Whereas SCRIB is known to regulate early stages of mouse mammary gland development, its function in the adult gland is not known. Using an inducible RNA interference (RNAi) mouse model for downregulating SCRIB expression, we report an unexpected role for SCRIB as a positive regulator of cell proliferation during pregnancy-associated mammary alveologenesis. SCRIB was required in the epithelial cell compartment of the mammary gland. Lack of SCRIB attenuated prolactin-induced activation of the JAK2-STAT5 signaling pathway. In addition, loss of SCRIB resulted in the downregulation of prolactin receptor (PRLR) at cell surface and its accumulation in intracellular structures that express markers of the Golgi complex and the recycling endosome. Unlike its role in virgin gland as a negative regulator cell proliferation, SCRIB is a positive regulator of mammary epithelial cell proliferation during pregnancy.

Methionyl-Methionine Promotes α-s1 Casein Synthesis in Bovine Mammary Gland Explants by Enhancing Intracellular Substrate Availability and Activating JAK2-STAT5 and mTOR-Mediated Signaling Pathways1–3

Background: Interest is increasing in the role of peptide-bound amino acids (AAs) in milk protein synthesis because studies have found that the uptake of some essential AAs by the mammary gland cannot meet the requirements for milk protein synthesis. Although the role of dipeptides in milk protein synthesis is clearly established, little is known about the underlying mechanisms.Objective: The objective of this study was to determine whether small peptides can be taken up intact by the peptide transporters in mammary tissue explants and the underlying mechanisms of the effects of methionyl-methionine (Met-Met) supplementation on milk protein synthesis.Methods: Mammary tissue explants were cultured in conditional medium and then treated with different concentrations of Met-Met that replaced 0%, 5%, 10%, 15%, 20%, and 25% of free Met for another 24 h. In some experiments, explants were cultured with an optimal dose of Met-Met with or without the inhibitors of peptide transporter 2 [PepT2; diethylpyrocarbonate (DEPC), 0.1 mmol/L] and aminopeptidase N (APN; bestatin, 20 μmol/L) for 24 h.Results: The substitutions of 15% free Met with Met-Met significantly promoted α-s1 casein (αs1-CN) expression in the mammary explants (P < 0.05). The inhibition of the PepT2 by DEPC or APN by bestatin significantly decreased the Met-Met–stimulated increase of αs1-CN expression (P < 0.05). Compared with the control group (0% Met-Met), absorption of Val, Met, Leu, Phe, Lys, and His was improved, and mRNA abundance of the neutral and basic AA transporter was increased in the 15% Met-Met group (P < 0.05). In addition, the mRNA abundance of the mammalian target of rapamycin (mTOR), p70 ribosomal S6 kinase 1 gene, eukaryotic initiation factor 4E binding protein 1 gene , Janus kinase 2 (JAK2), and signal transducer and activator of transcription 5 (STAT5) was increased in the 15% Met-Met–treated group (P < 0.05).Conclusion: Met-Met promoted αs1-CN synthesis in cultured bovine mammary gland explants, and this stimulation may be mediated by enhanced intracellular substrate availability and by activating JAK2-STAT5 and mTOR signaling pathways.

Abstract 4369: Rearrangements of the erythropoietin receptor are recurrent in Ph-like acute lymphoblastic leukemia and are sensitive to Jak2 inhibition

Abstract Introduction: Ph-like acute lymphoblastic leukemia (ALL) is characterized by a diverse range of genetic alterations that activate cytokine receptor and kinase signaling. We recently identified (Roberts KG, NEJM 2014) rearrangements of the erythropoietin receptor (EPOR) with immunoglobulin heavy (IGH) or kappa (IGK) chain loci in 154 Ph-like ALL. Here, we aimed to investigate their spectrum and recurrence in an extended cohort, as well as their pathogenic role and therapeutic potential in childhood Ph-like ALL. Methods: Whole transcriptome sequencing, real-time quantitative PCR (qPCR) and Sanger sequencing were performed to detect and map the EPOR rearrangements in 307 Ph-like ALL. Wild-type or EPOR rearranged alleles were expressed in IL-3-dependent mouse hematopoietic Ba/F3 cells and IL-7-dependent pre-B cells harboring alterations of Arf and/or the dominant negative IKZF1 allele IK6. Proliferation and downstream EPOR signaling were examined in absence or presence of erythropoietin (EPO). Leukemic growth was monitored in C57BL/6 mice transplanted with Arf-/- pre-B cells expressing rearranged EPOR. Luciferase-marked xenografts were established in NOD-SCID-IL2R gamma (NSG) null mice. Signaling, EPO-dependent proliferation and sensitivity to the JAK inhibitors were assessed ex vivo and in vivo. Results: EPOR rearrangements were identified in 8.3% of Ph-like ALL as the result of: i) inversion and cryptic insertion under the promoter region of IGH/IGK; ii) reciprocal translocation; or iii) fusion to 5′ LAIR1. All rearrangements resulted in ectopic overexpression of a C-terminal truncated receptor, confirmed by qPCR, that retained the phosphorylation site required for STAT5 activation, but lacked multiple tyrosine residues required for normal negative regulation. The rearranged alleles were expressed at higher and more prolonged levels than wild-type EPOR in Ba/F3 and Arf-/- mouse pre-B cells, and sustained cell proliferation with increased STAT5 phosphorylation following exogenous EPO stimulation. In vivo, the truncated receptor promoted leukemia development in C57BL/6 mice. Xenografted EPOR-rearranged leukemic cells exhibited high levels of truncated EPOR, STAT5 phosphorylation and ex vivo sensitivity to JAK2 inhibition using ruxolitinib, fedratinib, momelotinib, or pacritinib alone or in combination with daunrobucin, vincristine or dexamethasone (synergistic effect). The efficacy of Jak2 inhibition and the synergistic effect of combining ruxolitinib and dexamethasone were subsequently demonstrated in vivo. Conclusions: EPOR rearrangements are recurrent in Ph-like ALL and result in ectopic expression of truncated EPOR and activation of JAK2-STAT5 signaling pathway, sustaining leukemia development in vivo. Xenografted EPOR-rearranged leukemia cells exhibit ex vivo and in vivo sensitivity to JAK2 inhibitors alone or in combination with chemotherapy. Citation Format: Ilaria Iacobucci, Kathryn G. Roberts, Yongjin Li, Jinghui Zhang, Richard C. Harvey, Debbie Payne-Turner, Marcus Valentine, Kelly McCastlain, John Easton, I-Ming Chen, Michael Rusch, Steven M. Kornblau, Marina Konopleva, Elisabeth Paietta, Jacob M. Rowe, Ching-Hon Pui, Julie M. Gastier-Foster, Shalini Reshmi, Mignon L. Loh, Cheryl Willman, James R. Downing, Stephen P. Hunger, Charles G. Mullighan. Rearrangements of the erythropoietin receptor are recurrent in Ph-like acute lymphoblastic leukemia and are sensitive to Jak2 inhibition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4369. doi:10.1158/1538-7445.AM2015-4369

A Vine-copula Based Adaptive MCMC Sampler for Efficient Inference of Dynamical Systems

Statistical inference in high dimensional dynamical systems is often hindered by the unknown dependency structure of model parameters. In particu- lar, the inference of parameterized differential equations (DEs) via Markov chain Monte Carlo (MCMC) samplers often suffers from high proposal rejection rates and is exacerbated by strong autocorrelation structures within the Markov chains leading to poor mixing properties. In this paper, we develop a novel vine-copula based adaptive MCMC approach for efficient parameter inference in dynamical systems with strong parameter interdependence. We exploit the concept of a vine-copula decomposition of distribution densities in order to generate problem- specific proposals for a hybrid independence/random walk Metropolis-Hastings (MH) sampler. The key advantage of this approach is that the corresponding MH proposals generate independent samples from the posterior distribution more effi- ciently than common competitors. All copula densities can be updated during the sampling procedure for fine-tuning. The performance of our method is assessed on two small-scale examples and finally evaluated on a delay DE model for the JAK2-STAT5 signaling pathway fitted to time-resolved western blot data. We compare our copula-based approach to an independence sampler, a second-order moment-based random walk MH algorithm, and an adaptive MH sampler.