Impact of the Serotonin-Transporter-Polymorphism (5-HTTLPR) and Stressful Life Events on the Stress Response in Humans: Impact of the Serotonin-Transporter-Polymorphism (5-HTTLPR) and Stressful Life Events on the Stress Response in Humans

The 5-HTT gene (SLC6A4) is regulated by a common polymorphism in the promoter region (5-HTTLPR), which has functional consequences. Two major alleles have been observed and shown to have differential transcriptional activity with the long (L) allele having greater gene expression than the short (S) allele. 5-HTTLPR appears to modulate depression, anxiety and personality traits such as neuroticism. Additionally, a significant influence of 5-HTTLPR genotype on amygdala reactivity in response to fearful stimuli has been reported. Moreover, 5-HTTLPR seems to impact on the role of stressful life events (SLEs) in the development of depression. An elevated risk of depression and suicidal behaviors has been found in carriers of at least one low expressing S allele who had experienced SLEs, suggesting a gene x environment interaction. However, a recent meta-analysis showed that several findings failed to replicate this finding. Since genetic polymorphisms of the dopaminergic and serotonergic neurotransmission interact at the molecular, analyses with another polymorphism of the dopaminergic system, the dopamine D4 receptor (DRD4) was included to consider these likely gene-gene interactions (epistasis). The aim of this series of studies was to investigate the role 5-HTTLPR and SLEs on the endocrine stress response in different age samples. While newborns have been examined by a heel prick, stress responses were provoked in children (8-12 yrs) and younger adults (19-31 yrs) and older adults (54-68 yrs.) with the Trier Social Stress Test (TSST). The Life History Calendar (LHC) and Life Events Questionnaire (LEQ) were used to acquire data on SLEs. While in newborns the S/S genotype showed a significantly higher acute endocrine stress response than L/L or S/L genotypes, no significant difference between genotype groups was found in children. In the younger adult sample, the genotype impacted on cortisol stress responsiveness was reversed. Adults carrying the more active L allele of the 5-HTTLPR polymorphism showed a significantly larger cortisol response to the TSST than individuals carrying at least one of the lower expressing S allele. In older adults, no significant difference between genotype groups was found. However, results point in the same direction with showing highest cortisol response in individuals with L/L genotype. These data suggest that the association between 5-HTTLPR and endocrine stress reactivity seems to alter across lifespan, more specific the effects of genotype turns around. In addition, a significant interaction effect of 5-HTTLPR and SLEs has been found in the sample of younger adults, i.e. that early SLE as well as a severe number SLEs across the entire lifespan seem to modulate the interaction between HPA axis activity and 5-HTTLPR genotype. Additionally, a DRD4 by 5-HTTLPR interaction emerged which point to independent and joint effects of these polymorphisms on stress responsivity with regard to the concept of genegene interaction

Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites

Natural fibres have a high potential as reinforcement of polymer matrices, as they combine a high specific strength and modulus with sustainable production and reasonable prices. Modifying the fibre surface is a common method to increase the adhesion and thereby enhance the mechanical properties of composites. In this study, a novel sustainable surface treatment is presented: the fungal enzyme laccase was utilised with the aim of covalently binding the coupling agent dopamine to flax fibre surfaces. The goal is to improve the interfacial strength towards an epoxy matrix. SEM and AFM micrographs showed that the modification changes the surface morphology, indicating a deposition of dopamine on the surface. Fibre tensile tests, which were performed to check whether the fibre structure was damaged during the treatment, showed that no decrease in tensile strength or modulus occurred. Single fibre pullout tests showed a 30% increase in interfacial shear strength (IFSS) due to the laccase-mediated bonding of the coupling agent dopamine. These results demonstrate that a laccase + dopamine treatment modifies flax fibres sustainably and increases the interfacial strength towards epoxy

Protein Kinase D2 Is an Essential Regulator of Murine Myoblast Differentiation

Muscle differentiation is a highly conserved process that occurs through the activation of quiescent satellite cells whose progeny proliferate, differentiate, and fuse to generate new myofibers. A defined pattern of myogenic transcription factors is orchestrated during this process and is regulated via distinct signaling cascades involving various intracellular signaling pathways, including members of the protein kinase C (PKC) family. The protein kinase D (PKD) isoenzymes PKD1, -2, and -3, are prominent downstream targets of PKCs and phospholipase D in various biological systems including mouse and could hence play a role in muscle differentiation. In the present study, we used a mouse myoblast cell line (C2C12) as an in vitro model to investigate the role of PKDs, in particular PKD2, in muscle stem cell differentiation. We show that C2C12 cells express all PKD isoforms with PKD2 being highly expressed. Furthermore, we demonstrate that PKD2 is specifically phosphorylated/activated during the initiation of mouse myoblast differentiation. Selective inhibition of PKCs or PKDs by pharmacological inhibitors blocked myotube formation. Depletion of PKD2 by shRNAs resulted in a marked inhibition of myoblast cell fusion. PKD2-depleted cells exhibit impaired regulation of muscle development-associated genes while the proliferative capacity remains unaltered. Vice versa forced expression of PKD2 increases myoblast differentiation. These findings were confirmed in primary mouse satellite cells where myotube fusion was also decreased upon inhibition of PKDs. Active PKD2 induced transcriptional activation of myocyte enhancer factor 2D and repression of Pax3 transcriptional activity. In conclusion, we identify PKDs, in particular PKD2, as a major mediator of muscle cell differentiation in vitro and thereby as a potential novel target for the modulation of muscle regeneration

Tbx3 fosters pancreatic cancer growth by increased angiogenesis and activin/nodal-dependent induction of stemness

AbstractCell fate decisions and pluripotency, but also malignancy depend on networks of key transcriptional regulators. The T-box transcription factor TBX3 has been implicated in the regulation of embryonic stem cell self-renewal and cardiogenesis. We have recently discovered that forced TBX3 expression in embryonic stem cells promotes mesendoderm specification directly by activating key lineage specification factors and indirectly by enhancing paracrine NODAL signalling. Interestingly, aberrant TBX3 expression is associated with breast cancer and melanoma formation. In other cancers, loss of TBX3 expression is associated with a more aggressive phenotype e.g. in gastric and cervical cancer. The precise function of TBX3 in pancreatic ductal adenocarcinoma remains to be determined. In the current study we provide conclusive evidence for TBX3 overexpression in pancreatic cancer samples as compared to healthy tissue. While proliferation remains unaltered, forced TBX3 expression strongly increases migration and invasion, but also angiogenesis in vitro and in vivo. Finally, we describe the TBX3-dependency of cancer stem cells that perpetuate themselves through an autocrine TBX3–ACTIVIN/NODAL signalling loop to sustain stemness. Thus, TBX3 is a new key player among pluripotency-related genes driving cancer formation

Human pluripotent stem cell-derived acinar/ductal organoids generate human pancreas upon orthotopic transplantation and allow disease modelling

Objective The generation of acinar and ductal cells from human pluripotent stem cells (PSCs) is a poorly studied process, although various diseases arise from this compartment. Design We designed a straightforward approach to direct human PSCs towards pancreatic organoids resembling acinar and ductal progeny. Results Extensive phenotyping of the organoids not only shows the appropriate marker profile but also ultrastructural, global gene expression and functional hallmarks of the human pancreas in the dish. Upon orthotopic transplantation into immunodeficient mice, these organoids form normal pancreatic ducts and acinar tissue resembling fetal human pancreas without evidence of tumour formation or transformation. Finally, we implemented this unique phenotyping tool as a model to study the pancreatic facets of cystic fibrosis (CF). For the first time, we provide evidence that in vitro, but also in our xenograft transplantation assay, pancreatic commitment occurs generally unhindered in CF. Importantly, cystic fibrosis transmembrane conductance regulator (CFTR) activation in mutated pancreatic organoids not only mirrors the CF phenotype in functional assays but also at a global expression level. We also conducted a scalable proof-of-concept screen in CF pancreatic organoids using a set of CFTR correctors and activators, and established an mRNA-mediated gene therapy approach in CF organoids. Conclusions Taken together, our platform provides novel opportunities to model pancreatic disease and development, screen for disease-rescuing agents and to test therapeutic procedures.This study was funded by the Deutsche Forschungsgemeinschaft (DFG, K.L. 2544/1-1 and 1-2), the Forschungskern SyStaR to AK, BIU (Böhringer Ingelheim Ulm to AK), the Fritz-Thyssen Foundation (Az. 10.15.2.040), the German Cancer Aid (111879) and the Else-Kröner-Fresenius-Stiftung (2011_A200). AK is indebted to the Baden-Württemberg Stiftung for the financial support of this research project by the Eliteprogramme for Postdocs. AK is also an Else-Kröner-Fresenius Memorial Fellow. LP is supported by a research fellowship of the Else-Kröner-Fresenius-Stiftung. MH was supported by the International Graduate School in Molecular Medicine and the Bausteinprogramme (L.SBN. 110), Ulm University. MM is supported by a grant of Ulm University (Baustein for Senior Clinician Scientists). IGC is funded by the Interdisciplinary Center for Clinical Research (IZKF Aachen) and Start Program, RWTH Aachen University Medical School, Aachen, German