iSuRe-HadCre is an essential tool for effective conditional genetics.

Methods for modifying gene function at high spatiotemporal resolution in mice have revolutionized biomedical research, with Cre-loxP being the most widely used technology. However, the Cre-loxP technology has several drawbacks, including weak activity, leakiness, toxicity, and low reliability of existing Cre-reporters. This is mainly because different genes flanked by loxP sites (floxed) vary widely in their sensitivity to Cre-mediated recombination. Here, we report the generation, validation, and utility of iSuRe-HadCre, a new dual Cre-reporter and deleter mouse line that avoids these drawbacks. iSuRe-HadCre achieves this through a novel inducible dual-recombinase genetic cascade that ensures that cells expressing a fluorescent reporter had only transient Cre activity, that is nonetheless sufficient to effectively delete floxed genes. iSuRe-HadCre worked reliably in all cell types and for the 13 floxed genes tested. This new tool will enable the precise, efficient, and trustworthy analysis of gene function in entire mouse tissues or in single cells.

SUMOylation of PDGF receptor α affects signaling via PLCγ and STAT3, and cell proliferation.

BACKGROUND: The platelet-derived growth factor (PDGF) family of ligands exerts their cellular effects by binding to α- and ß-tyrosine kinase receptors (PDGFRα and PDGFRß, respectively). SUMOylation is an important posttranslational modification (PTM) which regulates protein stability, localization, activation and protein interactions. A mass spectrometry screen has demonstrated SUMOylation of PDGFRα. However, the functional role of SUMOylation of PDGFRα has remained unknown. RESULTS: In the present study, we validated that PDGFRα is SUMOylated on lysine residue 917 as was previously reported using a mass spectrometry approach. Mutation of lysine residue 917 to arginine (K917R) in PDGFRα substantially decreased SUMOylation, indicating that this amino acid residue is a major SUMOylation site. Whereas no difference in the stability of wild-type and mutant receptor was observed, the K917R mutant PDGFRα was less ubiquitinated than wild-type PDGFRα. The internalization and trafficking of the receptor to early and late endosomes were not affected by the mutation, neither was the localization of the PDGFRα to Golgi. However, the K917R mutant PDGFRα showed delayed activation of PLC-γ and enhanced activation of STAT3. Functional assays showed that the mutation of K917 of PDGFRα decreased cell proliferation in response to PDGF-BB stimulation. CONCLUSIONS: SUMOylation of PDGFRα decreases ubiquitination of the receptor and affects ligand-induced signaling and cell proliferation.

The type II TGF-ß receptor phosphorylates Tyr182 in the type I receptor to activate downstream Src signaling.

Transforming growth factor-ß (TGF-ß) signaling has important roles during embryonic development and in tissue homeostasis. TGF-ß ligands exert cellular effects by binding to type I (TßRI) and type II (TßRII) receptors and inducing both SMAD-dependent and SMAD-independent intracellular signaling pathways, the latter of which includes the activation of the tyrosine kinase Src. We investigated the mechanism by which TGF-ß stimulation activates Src in human and mouse cells. Before TGF-ß stimulation, inactive Src was complexed with TßRII. Upon TGF-ß1 stimulation, TßRII associated with and phosphorylated TßRI at Tyr182. Binding of Src to TßRI involved the interaction of the Src SH2 domain with phosphorylated Tyr182 and the interaction of the Src SH3 domain with a proline-rich region in TßRI and led to the activation of Src kinase activity and Src autophosphorylation. TGF-ß1-induced Src activation required the kinase activities of TßRII and Src but not that of TßRI. Activated Src also phosphorylated TßRI on several tyrosine residues, which may stabilize the binding of Src to the receptor. Src activation was required for the ability of TGF-ß to induce fibronectin production and migration in human breast carcinoma cells and to induce α-smooth muscle actin and actin reorganization in mouse fibroblasts. Thus, TGF-ß induces Src activation by stimulating a direct interaction with TßRI that depends on tyrosine phosphorylation of TßRI by TßRII.

Platelet-Derived PDGFB Promotes Recruitment of Cancer-Associated Fibroblasts, Deposition of Extracellular Matrix and Tgfß Signaling in the Tumor Microenvironment.

Platelets constitute a major reservoir of platelet-derived growth factor B (PDGFB) and are continuously activated in the tumor microenvironment, exposing tumors to the plethora of growth factors contained in platelet granules. To address the specific role of platelet-derived PDGFB in the tumor microenvironment, we have created a mouse model with conditional knockout of PDGFB in platelets (pl-PDGFB KO). Lack of PDGFB in platelets resulted in 10-fold lower PDGFB concentration in the tumor microenvironment, fewer cancer-associated fibroblasts and reduced deposition of the extracellular matrix (ECM) molecules fibronectin and collagen I in the orthotopic RIP1-Tag2 model for pancreatic neuroendocrine cancer. Myosin light chain phosphorylation, promoting cell contraction and, consequently, the mechano-induced release of active transforming growth factor (TGF) ß from extracellular compartments, was reduced in tumors from pl-PDGFB KO mice. In agreement, TGFß signaling, measured as phosphorylated Smad2, was significantly hampered in tumors from mice lacking PDGFB in their platelets, providing a plausible explanation for the reduced deposition of extracellular matrix. These findings indicate a major contribution of platelet-derived PDGFB to a malignant transformation of the tumor microenvironment and address for the first time the role of PDGFB released specifically from platelets in the remodeling of the ECM in tumors.

Smad7 Enhances TGF-ß-Induced Transcription of c-Jun and HDAC6 Promoting Invasion of Prostate Cancer Cells.

Transforming growth factor ß (TGF-ß) enhances migration and invasion of cancer cells, causing life-threatening metastasis. Smad7 expression is induced by TGF-ß to control TGF-ß signaling in a negative feedback manner. Here we report an additional function of Smad7, i.e., to enhance TGF-ß induction of c-Jun and HDAC6 via binding to their regulatory regions, promoting migration and invasion of prostate cancer cells. Lysine 102 in Smad7 is crucial for binding to specific consensus sites in c-Jun and HDAC6, even when endogenous Smad2, 3, and 4 were silenced by siRNA. A correlation between the mRNA expression of Smad7 and HDAC6, Smad7 and c-Jun, and c-Jun and HDAC6 was found in public databases from analyses of prostate cancer tissues. High expression of Smad7, HDAC6, and c-Jun correlated with poor prognosis for patients with prostate cancer. The knowledge that Smad7 can activate transcription of proinvasive genes leading to prostate cancer progression provides clinically relevant information.

Platelet-Specific PDGFB Ablation Impairs Tumor Vessel Integrity and Promotes Metastasis.

Platelet-derived growth factor B (PDGFB) plays a crucial role in recruitment of PDGF receptor ß-positive pericytes to blood vessels. The endothelium is an essential source of PDGFB in this process. Platelets constitute a major reservoir of PDGFB and are continuously activated in the tumor microenvironment, exposing tumors to the plethora of growth factors contained in platelet granules. Here, we show that tumor vascular function, as well as pericyte coverage is significantly impaired in mice with conditional knockout of PDGFB in platelets. A lack of PDGFB in platelets led to enhanced hypoxia and epithelial-to-mesenchymal transition in the primary tumors, elevated levels of circulating tumor cells, and increased spontaneous metastasis to the liver or lungs in two mouse models. These findings establish a previously unknown role for platelet-derived PDGFB, whereby it promotes and maintains vascular integrity in the tumor microenvironment by contributing to the recruitment of pericytes. SIGNIFICANCE: Conditional knockout of PDGFB in platelets demonstrates its previously unknown role in the maintenance of tumor vascular integrity and host protection against metastasis.

Artificially Enhancing and Suppressing Hippocampus-Mediated Memories.

Emerging evidence indicates that distinct hippocampal domains differentially drive cognition and emotion [1, 2]; dorsal regions encode spatial, temporal, and contextual information [3-5], whereas ventral regions regulate stress responses [6], anxiety-related behaviors [7, 8], and emotional states [8-10]. Although previous studies demonstrate that optically manipulating cells in the dorsal hippocampus can drive the behavioral expression of positive and negative memories, it is unknown whether changes in cellular activity in the ventral hippocampus can drive such behaviors [11-14]. Investigating the extent to which distinct hippocampal memories across the longitudinal axis modulate behavior could aid in the understanding of stress-related psychiatric disorders known to affect emotion, memory, and cognition [15]. Here, we asked whether tagging and stimulating cells along the dorsoventral axis of the hippocampus could acutely, chronically, and differentially promote context-specific behaviors. Acute reactivation of both dorsal and ventral hippocampus cells that were previously active during memory formation drove freezing behavior, place avoidance, and place preference. Moreover, chronic stimulation of dorsal or ventral hippocampal fear memories produced a context-specific reduction or enhancement of fear responses, respectively, thus demonstrating bi-directional and context-specific modulation of memories along the longitudinal axis of the hippocampus. Fear memory suppression was associated with a reduction in hippocampal cells active during retrieval, while fear memory enhancement was associated with an increase in basolateral amygdala activity. Together, our data demonstrate that discrete sets of cells throughout the hippocampus provide key nodes sufficient to bi-directionally reprogram both the neural and behavioral expression of memory.

TANK-binding kinase 1 is a mediator of platelet-induced EMT in mammary carcinoma cells.

Platelets can promote several stages of the metastatic process and thus contribute to malignant progression. As an example, platelets promote invasive properties of tumor cells by induction of epithelial to mesenchymal transition (EMT). In this study, we show that tumor necrosis factor receptor-associated factor (TRAF) family member-associated NF-κB activator (TANK)-binding kinase 1 (TBK1) is a previously unknown mediator of platelet-induced EMT in mammary carcinoma cells. Coculture of 2 mammary carcinoma cell lines, Ep5 from mice and MCF10A(MII) from humans, with isolated platelets induced morphologic as well as molecular changes characteristic of EMT, which was paralleled with activation of TBK1. TBK1 depletion using small interfering RNA impaired platelet-induced EMT in both Ep5 and MCF10A(MII) cells. Furthermore, platelet-induced activation of the NF-κB subunit p65 was suppressed after TBK1 knockdown, demonstrating that TBK1 mediates platelet-induced NF-κB signaling and EMT. Using an in vivo metastasis assay, we found that depletion of TBK1 from mammary carcinoma cells during in vitro preconditioning with platelets subsequently suppressed the formation of lung metastases in mice. Altogether, these results suggest that TBK1 contributes to tumor invasiveness and may be a driver of metastatic spread in breast cancer.-Zhang, Y., Unnithan, R. V. M., Hamidi, A., Caja, L., Saupe, F., Moustakas, A., Cedervall, J., Olsson, A.-K. TANK-binding kinase 1 is a mediator of platelet-induced EMT in mammary carcinoma cells.

Memory: The Majestic Case of an Amnestic Trace.

Memories formed during infancy are forgotten in adulthood, a phenomenon called 'infantile amnesia'. New research suggests that these memories can be artificially recovered in adulthood, suggesting that they were never completely lost in the first place.

Platelets, NETs and cancer.

In addition to the central role of platelets in hemostasis, they contribute to pathological conditions such as inflammation and tumor progression. Aberrant expression and/or exposure of pro-coagulant factors in the tumor microenvironment induce platelet activation and subsequent release of growth factors from platelet granules. Cancer patients are commonly affected by thrombotic events, as a result of tumor-induced platelet activation. A novel player potentially contributing to cancer-associated thrombosis is the formation of neutrophil extracellular traps (NETs). NETs are composed of externalized DNA of nuclear or mitochondrial origin, bound to histones and granular proteases such as neutrophil elastase (NE) and myeloperoxidase (MPO). These extracellular traps help neutrophils to catch and kill pathogens such as bacteria, virus and fungi. It is now clear that NETs form also under conditions of sterile inflammation such as cancer and autoimmunity and can promote thrombosis. Recent data show that platelets play a key role in determining when and where NETs should form. This review will highlight our current insight in the role of platelets as regulators of NET formation, both during infection and sterile inflammation.

Insight meditation and telomere biology: The effects of intensive retreat and the moderating role of personality.

A growing body of evidence suggests that meditation training may have a range of salubrious effects, including improved telomere regulation. Telomeres and the enzyme telomerase interact with a variety of molecular components to regulate cell-cycle signaling cascades, and are implicated in pathways linking psychological stress to disease. We investigated the effects of intensive meditation practice on these biomarkers by measuring changes in telomere length (TL), telomerase activity (TA), and telomere-related gene (TRG) expression during a 1-month residential Insight meditation retreat. Multilevel analyses revealed an apparent TL increase in the retreat group, compared to a group of experienced meditators, similarly comprised in age and gender, who were not on retreat. Moreover, personality traits predicted changes in TL, such that retreat participants highest in neuroticism and lowest in agreeableness demonstrated the greatest increases in TL. Changes observed in TRGs further suggest retreat-related improvements in telomere maintenance, including increases in Gar1 and HnRNPA1, which encode proteins that bind telomerase RNA and telomeric DNA. Although no group-level changes were observed in TA, retreat participants' TA levels at post-assessment were inversely related to several indices of retreat engagement and prior meditation experience. Neuroticism also predicted variation in TA across retreat. These findings suggest that meditation training in a retreat setting may have positive effects on telomere regulation, which are moderated by individual differences in personality and meditation experience. (ClinicalTrials.gov #NCT03056105).

A Case of Cushing's Syndrome in Pregnancy.

Cushing's syndrome (CS) occurs rarely during pregnancy. CS can be caused by prolonged abnormal exposure to excess glucocorticoids leading to special and significant signs and symptoms. It is often difficult to diagnose pathological hypercortisolism in pregnant women since some symptoms of the disease might be due to a complicated pregnancy, including preeclampsia or gestational diabetes. In this study, we report the case of a 29-year-old female who referred to our institution with hypertension, weakness, steria, and truncal obesity. Physical examination revealed cushingoid characteristic. She was also found to be 27 weeks pregnant. CS was diagnosed on the basis of abnormal serum cortisol and adrenocorticotropin hormone (ACTH) levels, as well as radiologic findings. She eventually gave birth to a preterm infant via vaginal delivery. A right adrenal adenoma was diagnosed and was subsequently treated with surgical resection. The patient's condition remained stable after the surgery.

Single-centre retrospective analysis of growth hormone supplementation in IVF patients classified as poor-prognosis.

BACKGROUND: Patients undergoing in vitro fertilisation (IVF) receive various adjuvant therapies in order to enhance success rates, but the true benefit is actively debated. Growth hormone (GH) supplementation was assessed in poor-prognosis women undergoing fresh IVF transfer cycles. METHODS: Data were retrospectively analysed from 400 IVF cycles, where 161 women received GH and 239 did not. RESULTS: Clinical pregnancy, live birth rates and corresponding ORs and CIs were significantly greater with GH, despite patients being significantly older with lower ovarian reserve. Patient's age, quality of transferred embryo and GH were the only significant independent predictors of clinical pregnancy (OR: 0.90, 5.00 and 2.49, p<0.002, respectively) and live birth chance (OR: 0.91, 3.90 and 4.75, p<0.014, respectively). GH increased clinical pregnancy chance by 3.42-fold (95% CI 1.82 to 6.44, p<0.0005) and live birth chance by 6.16-fold (95% CI 2.83 to 13.39, p<0.0005) after adjustment for maternal age, antral follicle count and transferred embryo quality. CONCLUSION: These data provided further evidence to indicate that GH may support more live births, particularly in younger women. It also appears that embryos generated under GH have a better implantation potential, but whether the biological mechanism is embryo-mediated or endometrium-mediated is unclear.

TGF-ß promotes PI3K-AKT signaling and prostate cancer cell migration through the TRAF6-mediated ubiquitylation of p85α.

Transforming growth factor-ß (TGF-ß) is a pluripotent cytokine that regulates cell fate and plasticity in normal tissues and tumors. The multifunctional cellular responses evoked by TGF-ß are mediated by the canonical SMAD pathway and by noncanonical pathways, including mitogen-activated protein kinase (MAPK) pathways and the phosphatidylinositol 3'-kinase (PI3K)-protein kinase B (AKT) pathway. We found that TGF-ß activated PI3K in a manner dependent on the activity of the E3 ubiquitin ligase tumor necrosis factor receptor-associated factor 6 (TRAF6). TRAF6 polyubiquitylated the PI3K regulatory subunit p85α and promoted the formation of a complex between the TGF-ß type I receptor (TßRI) and p85α, which led to the activation of PI3K and AKT. Lys63-linked polyubiquitylation of p85α on Lys513 and Lys519 in the iSH2 (inter-Src homology 2) domain was required for TGF-ß-induced activation of PI3K-AKT signaling and cell motility in prostate cancer cells and activated macrophages. Unlike the activation of SMAD pathways, the TRAF6-mediated activation of PI3K and AKT was not dependent on the kinase activity of TßRI. In situ proximity ligation assays revealed that polyubiquitylation of p85α was evident in aggressive prostate cancer tissues. Thus, our data reveal a molecular mechanism by which TGF-ß activates the PI3K-AKT pathway to drive cell migration.

Comprehensive evaluation of the neuropeptide-Y gene variants in the risk of obesity: a case-control study and meta-analysis.

BACKGROUND: Orexigenic actions mediated by neuropeptide-Y (NPY) promote body weight regulation. Genetic variations in the NPY gene could therefore influence susceptibility to obesity, but results have been conflicting. We have carried out, for the first time, a case-control study to examine the effect of NPY rs16147 and rs5574 variants with the risk of obesity in Asians and also a meta-analysis to summarize the effect of these variants including that of the widely studied rs16139. MATERIALS AND METHODS: Genotypes and biochemistry data were determined for 942 children (262 cases and 680 controls) recruited from 23 randomly selected schools in Malaysia. Relevant articles were identified from Pubmed, Embase, Web of Science and Google Scholar. Data were extracted and summary estimates of the association between the NPY variants and obesity were examined. RESULTS: The frequency of the rs16147 T allele was significantly higher in the cases than controls (odds ratio 1.27, 95% confidence interval 1.04-1.55, P = 0.022), whereas the rs5574 T allele was significantly higher in the controls (odds ratio 0.76, 95% confidence interval 0.61-0.96, P = 0.020). In addition, NPY rs16147 was significantly correlated with obesity parameters including BMI, waist circumference, triglyceride and body fat percentage (P < 0.05). Meta-analysis including nine case-control studies further confirmed the findings of the association of the two variants with the risk of obesity and also found that rs16139 was associated with increased risk. CONCLUSION: This study suggests that NPY rs16147 T and rs16139 C minor alleles are associated with increased risk, whereas the minor allele T of the rs5574 is associated with a reduced risk of obesity.

Cortical representations are reinstated by the hippocampus during memory retrieval.

The hippocampus is assumed to retrieve memory by reinstating patterns of cortical activity that were observed during learning. To test this idea, we monitored the activity of individual cortical neurons while simultaneously inactivating the hippocampus. Neurons that were active during context fear conditioning were tagged with the long-lasting fluorescent protein H2B-GFP and the light-activated proton pump ArchT. These proteins allowed us to identify encoding neurons several days after learning and silence them with laser stimulation. When tagged CA1 cells were silenced, we found that memory retrieval was impaired and representations in the cortex (entorhinal, retrosplenial, perirhinal) and the amygdala could not be reactivated. Importantly, hippocampal inactivation did not alter the total amount of activity in most brain regions. Instead, it selectively prevented neurons that were active during learning from being reactivated during retrieval. These data provide functional evidence that the hippocampus reactivates specific memory representations during retrieval.

Acute D-serine treatment produces antidepressant-like effects in rodents.

Research suggests that dysfunctional glutamatergic signalling may contribute to depression, a debilitating mood disorder affecting millions of individuals worldwide. Ketamine, a N-methyl-D-aspartate (NMDA) receptor antagonist, exerts rapid antidepressant effects in approximately 70% of patients. Glutamate evokes the release of D-serine from astrocytes and neurons, which then acts as a co-agonist and binds at the glycine site on the NR1 subunit of NMDA receptors. Several studies have implicated glial deficits as one of the underlying facets of the neurobiology of depression. The present study tested the hypothesis that D-serine modulates behaviours related to depression. The behavioural effects of a single, acute D-serine administration were examined in several rodent tests of antidepressant-like effects, including the forced swim test (FST), the female urine sniffing test (FUST) following serotonin depletion, and the learned helplessness (LH) paradigm. D-serine significantly reduced immobility in the FST without affecting general motor function. Both D-serine and ketamine significantly rescued sexual reward-seeking deficits caused by serotonin depletion in the FUST. Finally, D-serine reversed LH behaviour, as measured by escape latency, number of escapes, and percentage of mice developing LH. Mice lacking NR1 expression in forebrain excitatory neurons exhibited a depression-like phenotype in the same behavioural tests, and did not respond to D-serine treatment. These findings suggest that D-serine produces antidepressant-like effects and support the notion of complex glutamatergic dysfunction in depression. It is unclear whether D-serine has a convergent influence on downstream synaptic plasticity cascades that may yield a similar therapeutic profile to NMDA antagonists like ketamine.

Polyubiquitination of transforming growth factor ß (TGFß)-associated kinase 1 mediates nuclear factor-κB activation in response to different inflammatory stimuli.

The transcription factor nuclear factor κB (NF-κB) plays a central role in regulating inflammation in response to several external signals. The TGFß-associated kinase 1 (TAK1) is an upstream regulator of NF-κB signaling. In TGFß-stimulated cells, TAK1 undergoes Lys-63-linked polyubiquitination at Lys-34 by TNF receptor-associated factor 6 and is thereby activated. The aim of this study was to investigate whether TAK1 polyubiquitination at Lys-34 is also essential for NF-κB activation via TNF receptor, IL-1 receptor and toll-like receptor 4. We observed that TAK1 polyubiquitination occurred at Lys-34 and required the E3 ubiquitin ligase TNF receptor-associated factor 6 after stimulation of cells with IL-1ß. Polyubiquitination of TAK1 also occurred at Lys-34 in cells stimulated by TNF-α and LPS, which activates TLR4, as well as in HepG2 and prostate cancer cells stimulated with TGFß, which in all cases resulted in NF-κB activation. Expression of a K34R-mutant TAK1 led to a reduced NF-κB activation, IL-6 promoter activity, and proinflammatory cytokine secretion by TNF-α-stimulated PC-3U cells. Similar results were obtained in the mouse macrophage cell line RAW264.7 after LPS treatment. In conclusion, polyubiquitination of TAK1 is correlated with activation of TAK1 and is essential for activation of NF-κB signaling downstream of several receptors.

Stable isotope-resolved metabolomic analysis of lithium effects on glial-neuronal metabolism and interactions.

Despite the long-established therapeutic efficacy of lithium in the treatment of bipolar disorder (BPD), its molecular mechanism of action remains elusive. Newly developed stable isotope-resolved metabolomics (SIRM) is a powerful approach that can be used to elucidate systematically how lithium impacts glial and neuronal metabolic pathways and activities, leading ultimately to deciphering its molecular mechanism of action. The effect of lithium on the metabolism of three different (13)C-labeled precursors ([U-(13)C]-glucose, (13)C-3-lactate or (13)C-2,3-alanine) was analyzed in cultured rat astrocytes and neurons by nuclear magnetic resonance (NMR) spectroscopy and gas chromatography mass spectrometry (GC-MS). Using [U-(13)C]-glucose, lithium was shown to enhance glycolytic activity and part of the Krebs cycle activity in both astrocytes and neurons, particularly the anaplerotic pyruvate carboxylation (PC). The PC pathway was previously thought to be active in astrocytes but absent in neurons. Lithium also stimulated the extracellular release of (13)C labeled-lactate, -alanine (Ala), -citrate, and -glutamine (Gln) by astrocytes. Interrogation of neuronal pathways using (13)C-3-lactate or (13)C-2,3-Ala as tracers indicated a high capacity of neurons to utilize lactate and Ala in the Krebs cycle, particularly in the production of labeled Asp and Glu via PC and normal cycle activity. Prolonged lithium treatment enhanced lactate metabolism via PC but inhibited lactate oxidation via the normal Krebs cycle in neurons. Such lithium modulation of glycolytic, PC and Krebs cycle activity in astrocytes and neurons as well as release of fuel substrates by astrocytes should help replenish Krebs cycle substrates for Glu synthesis while meeting neuronal demands for energy. Further investigations into the molecular regulation of these metabolic traits should provide new insights into the pathophysiology of mood disorders and early diagnostic markers, as well as new target(s) for effective therapies.