Splittings for C*-correspondences and strong shift equivalence

We present an extension of the notion of in-splits from symbolic dynamics to topological graphs and, more generally, to C*-correspondences. We demonstrate that in-splits provide examples of strong shift equivalences of C*-correspondences. Furthermore, we provide a streamlined treatment of Muhly, Pask, and Tomforde's proof that any strong shift equivalence of regular C*-correspondences induces a (gauge-equivariant) Morita equivalence between Cuntz-Pimsner algebras. For topological graphs, we prove that in-splits induce diagonal-preserving gauge-equivariant *-isomorphisms in analogy with the results for Cuntz-Krieger algebras. Additionally, we examine the notion of out-splits for C*-correspondences.Comment: 34 page

Morphisms of Cuntz-Pimsner algebras from completely positive maps

We introduce positive correspondences as right C*-modules with left actions given by completely positive maps. Positive correspondences form a semi-category that contains the C*-correspondence (Enchilada) category as a "retract". Kasparov's KSGNS construction provides a semi-functor from this semi-category onto the C*-correspondence category. The need for left actions by completely positive maps appears naturally when we consider morphisms between Cuntz-Pimsner algebras, and we describe classes of examples arising from projections on C*-correspondences and Fock spaces, as well as examples from conjugation by bi-Hilbertian bimodules of finite index.Comment: 32 page

Application of dielectric spectroscopy in an industrial bioprocess utilizing the baculovirus expression vector system

Doctor of PhilosophyDepartment of Chemical EngineeringPeter CzermakPeter H. PfrommLarge-scale insect cell culture utilizing the baculovirus expression vector system (BEVS) can be used to produce biopharmaceuticals such as vaccines and therapeutic proteins. Biopharmaceutical production processes are generally complex and sensitive to many process parameters and changes, but on-line monitoring in this area is relatively limited and the fundamental understanding of the intricate relationships between significant process parameters and the process outcome, especially on the multi-liter or multi-m3 scale, is rarely conclusive. Dielectric spectroscopy (DS), which is based on the frequency dependent measurement of the passive dielectric properties of materials, was applied to large-scale insect cell cultures infected with a baculovirus under low multiplicity of infection conditions to produce a recombinant protein of the virus-like particle class. DS not only allowed the qualitative monitoring of the infection and recombinant protein production process within the culture in real-time but also the detection of important culture events, e.g. the peak in baculovirus production/concentration. Additionally, DS seemed to be able to serve as a predictive tool for the overall recombinant protein yield early in the process. Partial Least Square models were successfully developed allowing monitoring of the cultures progress in terms of cell density, size, and even nutrient concentration replacing the need for discrete sampling and therefore reducing contamination risks. In summary, DS has been demonstrated to have the potential to increase bioprocess understanding and the repeatability of recombinant protein production in the BEVS but ultimately also to satisfy the increased requirements for process monitoring as delineated recently in the Process Analytical Technology initiative by the Food and Drug Administration

Cathepsin K deficiency in mice induces structural and metabolic changes in the central nervous system that are associated with learning and memory deficits

<p>Abstract</p> <p>Background</p> <p>Cathepsin K is a cysteine peptidase known for its importance in osteoclast-mediated bone resorption. Inhibitors of cathepsin K are in clinical trials for treatment of osteoporosis. However, side effects of first generation inhibitors included altered levels of related cathepsins in peripheral organs and in the central nervous system (CNS). Cathepsin K has been recently detected in brain parenchyma and it has been linked to neurobehavioral disorders such as schizophrenia. Thus, the study of the functions that cathepsin K fulfils in the brain becomes highly relevant.</p> <p>Results</p> <p>Cathepsin K messenger RNA was detectable in all brain regions of wild type (WT) mice. At the protein level, cathepsin K was detected by immunofluorescence microscopy in vesicles of neuronal and non-neuronal cells throughout the mouse brain. The hippocampus of WT mice exhibited the highest levels of cathepsin K activity in fluorogenic assays, while the cortex, striatum, and cerebellum revealed significantly lower enzymatic activities. At the molecular level, the proteolytic network of cysteine cathepsins was disrupted in the brain of cathepsin K-deficient (<it>Ctsk</it>^-/-) animals. Specifically, cathepsin B and L protein and activity levels were altered, whereas cathepsin D remained largely unaffected. Cystatin C, an endogenous inhibitor of cysteine cathepsins, was elevated in the striatum and hippocampus, pointing to regional differences in the tissue response to <it>Ctsk </it>ablation. Decreased levels of astrocytic glial fibrillary acidic protein, fewer and less ramified profiles of astrocyte processes, differentially altered levels of oligodendrocytic cyclic nucleotide phosphodiesterase, as well as alterations in the patterning of neuronal cell layers were observed in the hippocampus of <it>Ctsk</it>^-/-mice. A number of molecular and cellular changes were detected in other brain regions, including the cortex, striatum/mesencephalon, and cerebellum. Moreover, an overall induction of the dopaminergic system was found in <it>Ctsk</it>^-/-animals which exhibited reduced anxiety levels as well as short- and long-term memory impairments in behavioral assessments.</p> <p>Conclusion</p> <p>We conclude that deletion of the <it>Ctsk </it>gene can lead to deregulation of related proteases, resulting in a wide range of molecular and cellular changes in the CNS with severe consequences for tissue homeostasis. We propose that cathepsin K activity has an important impact on the development and maintenance of the CNS in mice.</p

Protective efficacy of an RBD-based Middle East respiratory syndrome coronavirus (MERS-CoV) particle vaccine in llamas

Ongoing outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) continue posing a global health threat. Vaccination of livestock reservoir species is a recommended strategy to prevent spread of MERS-CoV among animals and potential spillover to humans. Using a direct-contact llama challenge model that mimics naturally occurring viral transmission, we tested the efficacy of a multimeric receptor binding domain (RBD) particle-display based vaccine candidate. While MERS-CoV was transmitted to naive animals exposed to virus-inoculated llamas, immunization induced robust virus-neutralizing antibody responses and prevented transmission in 1/3 vaccinated, in-contact animals. Our exploratory study supports further improvement of the RBD-based vaccine to prevent zoonotic spillover of MERS-CoV

Protective efficacy of an RBD-based Middle East respiratory syndrome coronavirus (MERS-CoV) particle vaccine in llamas

Ongoing outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) continue posing a global health threat. Vaccination of livestock reservoir species is a recommended strategy to prevent spread of MERS-CoV among animals and potential spillover to humans. Using a direct-contact llama challenge model that mimics naturally occurring viral transmission, we tested the efficacy of a multimeric receptor binding domain (RBD) particle-display based vaccine candidate. While MERS-CoV was transmitted to naïve animals exposed to virus-inoculated llamas, immunization induced robust virus-neutralizing antibody responses and prevented transmission in 1/3 vaccinated, in-contact animals. Our exploratory study supports further improvement of the RBD-based vaccine to prevent zoonotic spillover of MERS-CoV

Adipose tissue ATGL modifies the cardiac lipidome in pressure-overload-induced left ventricular failure

Adipose tissue lipolysis occurs during the development of heart failure as a consequence of chronic adrenergic stimulation. However, the impact of enhanced adipose triacylglycerol hydrolysis mediated by adipose triglyceride lipase (ATGL) on cardiac function is unclear. To investigate the role of adipose tissue lipolysis during heart failure, we generated mice with tissue-specific deletion of ATGL (atATGL-KO). atATGL-KO mice were subjected to transverse aortic constriction (TAC) to induce pressure-mediated cardiac failure. The cardiac mouse lipidome and the human plasma lipidome from healthy controls (n = 10) and patients with systolic heart failure (HFrEF, n = 13) were analyzed by MS-based shotgun lipidomics. TAC-induced increases in left ventricular mass (LVM) and diastolic LV inner diameter were significantly attenuated in atATGL-KO mice compared to wild type (wt) -mice. More importantly, atATGL-KO mice were protected against TAC-induced systolic LV failure. Perturbation of lipolysis in the adipose tissue of atATGL-KO mice resulted in the prevention of the major cardiac lipidome changes observed after TAC in wt-mice. Profound changes occurred in the lipid class of phosphatidylethanolamines (PE) in which multiple PE-species were markedly induced in failing wt-hearts, which was attenuated in atATGL-KO hearts. Moreover, selected heart failure-induced PE species in mouse hearts were also induced in plasma samples from patients with chronic heart failure. TAC-induced cardiac PE induction resulted in decreased PC/PE-species ratios associated with increased apoptotic marker expression in failing wt-hearts, a process absent in atATGL-KO hearts. Perturbation of adipose tissue lipolysis by ATGL-deficiency ameliorated pressure-induced heart failure and the potentially deleterious cardiac lipidome changes that accompany this pathological process, namely the induction of specific PE species. Non-cardiac ATGL-mediated modulation of the cardiac lipidome may play an important role in the pathogenesis of chronic heart failure

The co-chaperone Fkbp5 shapes the acute stress response in the paraventricular nucleus of the hypothalamus of male mice

Disturbed activation or regulation of the stress response through the hypothalamic-pituitary-adrenal (HPA) axis is a fundamental component of multiple stress-related diseases, including psychiatric, metabolic, and immune disorders. The FK506 binding protein 51 (FKBP5) is a negative regulator of the glucocorticoid receptor (GR), the main driver of HPA axis regulation, and FKBP5 polymorphisms have been repeatedly linked to stress-related disorders in humans. However, the specific role of Fkbp5 in the paraventricular nucleus of the hypothalamus (PVN) in shaping HPA axis (re)activity remains to be elucidated. We here demonstrate that the deletion of Fkbp5 in Sim1(+) neurons dampens the acute stress response and increases GR sensitivity. In contrast, Fkbp5 overexpression in the PVN results in a chronic HPA axis over-activation, and a PVN-specific rescue of Fkbp5 expression in full Fkbp5 KO mice normalizes the HPA axis phenotype. Single-cell RNA sequencing revealed the cell-type-specific expression pattern of Fkbp5 in the PVN and showed that Fkbp5 expression is specifically upregulated in Crh(+) neurons after stress. Finally, Crh-specific Fkbp5 overexpression alters Crh neuron activity, but only partially recapitulates the PVN-specific Fkbp5 overexpression phenotype. Together, the data establish the central and cell-type-specific importance of Fkbp5 in the PVN in shaping HPA axis regulation and the acute stress response

Controlling absence seizures from the cerebellar nuclei via activation of the Gq signaling pathway

Absence seizures (ASs) are characterized by pathological electrographic oscillations in the cerebral cortex and thalamus, which are called spike-and-wave discharges (SWDs). Subcortical structures, such as the cerebellum, may well contribute to the emergence of ASs, but the cellular and molecular underpinnings remain poorly understood. Here we show that the genetic ablation of P/Q-type calcium channels in cerebellar granule cells (quirky) or Purkinje cells (purky) leads to recurrent SWDs with the purky model showing the more severe phenotype. The quirky mouse model showed irregular action potential firing of their cerebellar nuclei (CN) neurons as well as rhythmic firing during the wave of their SWDs. The purky model also showed irregular CN firing, in addition to a reduced firing rate and rhythmicity during the spike of the SWDs. In both models, the incidence of SWDs could be decreased by increasing CN activity via activation of the Gq-coupled designer receptor exclusively activated by designer drugs (DREADDs) or via that of the Gq-coupled metabotropic glutamate receptor 1. In contrast, the incidence of SWDs was increased by decreasing CN activity via activation of the inhibitory Gi/o-coupled DREADD. Finally, disrupting CN rhythmic firing with a closed-loop channelrhodopsin-2 stimulation protocol confirmed that ongoing SWDs can be ceased by activating CN neurons. Together, our data highlight that P/Q-type calcium channels in cerebellar granule cells and Purkinje cells can be relevant for epileptogenesis, that Gq-coupled activation of CN neurons can exert anti-epileptic effects and that precisely timed activation of the CN can be used to stop ongoing SWDs