Intensive Longitudinal Social Sensing in Patients With Psychosis Spectrum Disorders: An Exploratory Pilot Study

BACKGROUND

Psychosis spectrum disorders are characterized by significant alterations in social functioning, which is a major factor for patient recovery. Despite its importance, objectively quantifying the complex day-to-day social behavior in real-life settings has rarely been attempted. Here, we conducted a pilot study with wearable sensors that passively and continuously register interactions with other participants. We hypothesized that the amount and pattern of social interaction was associated with the severity of psychotic symptoms.

STUDY DESIGN

We recruited 7 patients with psychosis spectrum disorders and 18 team members from a Soteria-style ward. Each participant wore a radio frequency identification badge, sending and receiving signals from nearby badges, allowing passive quantification of social interactions. In addition, symptom severity was assessed weekly by the Positive and Negative Syndrome Scale (PANSS).

STUDY RESULTS

During an 11-week period, we identified 17 970 interactions among patients and staff. On average, patients spent 2.6 h per day interacting, capturing relevant aspects of daily social life. Relative daily interaction time, average interaction duration, and clustering coefficient, a measure of local network integration, were significantly associated with lower PANSS scores. Self-reported interaction time did not correlate with measured interaction time or with PANSS, indicating the importance of objective markers.

CONCLUSIONS

This pilot study demonstrates the feasibility of passively recording social interaction of patients and staff at high resolution and for a long observation period in a real-life setting in a psychiatric department. We show links between quantified social interaction and psychopathology that may facilitate development and personalization of targeted treatments.

In planta deglycosylation improves the SARS-CoV-2 neutralization activity of recombinant ACE2-Fc

SARS-CoV-2 infects human cells via binding of the viral spike glycoprotein to its main cellular receptor, angiotensin-converting enzyme 2 (ACE2). The spike protein-ACE2 receptor interaction is therefore a major target for the development of therapeutic or prophylactic drugs to combat coronavirus infections. Various engineered soluble ACE2 variants (decoys) have been designed and shown to exhibit virus neutralization capacity in cell-based assays and in vivo models. Human ACE2 is heavily glycosylated and some of its glycans impair binding to the SARS-CoV-2 spike protein. Therefore, glycan-engineered recombinant soluble ACE2 variants might display enhanced virus-neutralization potencies. Here, we transiently co-expressed the extracellular domain of ACE2 fused to human Fc (ACE2-Fc) with a bacterial endoglycosidase in Nicotiana benthamiana to produce ACE2-Fc decorated with N-glycans consisting of single GlcNAc residues. The endoglycosidase was targeted to the Golgi apparatus with the intention to avoid any interference of glycan removal with concomitant ACE2-Fc protein folding and quality control in the endoplasmic reticulum. The in vivo deglycosylated ACE2-Fc carrying single GlcNAc residues displayed increased affinity to the receptor-binding domain (RBD) of SARS-CoV-2 as well as improved virus neutralization activity and thus is a promising drug candidate to block coronavirus infection.

A consensus protocol for functional connectivity analysis in the rat brain

Task-free functional connectivity in animal models provides an experimental framework to examine connectivity phenomena under controlled conditions and allows for comparisons with data modalities collected under invasive or terminal procedures. Currently, animal acquisitions are performed with varying protocols and analyses that hamper result comparison and integration. Here we introduce StandardRat, a consensus rat functional magnetic resonance imaging acquisition protocol tested across 20 centers. To develop this protocol with optimized acquisition and processing parameters, we initially aggregated 65 functional imaging datasets acquired from rats across 46 centers. We developed a reproducible pipeline for analyzing rat data acquired with diverse protocols and determined experimental and processing parameters associated with the robust detection of functional connectivity across centers. We show that the standardized protocol enhances biologically plausible functional connectivity patterns relative to previous acquisitions. The protocol and processing pipeline described here is openly shared with the neuroimaging community to promote interoperability and cooperation toward tackling the most important challenges in neuroscience.

Predictors of complex PTSD: the role of trauma characteristics, dissociation, and comorbid psychopathology

BACKGROUND

Complex Posttraumatic Stress Disorder (CPTSD) has previously been associated with earlier trauma onset, repeated interpersonal traumatization, more dissociation, and more comorbid psychopathology. However, it is still debated if the afore-mentioned risk factors are related to CPTSD diagnosis or rather indicative of a more severe form of post-traumatic distress. The aim of this study was to compare patients with a CPTSD diagnosis to those with PTSD in trauma characteristics (onset, chronicity, interpersonal nature, familiarity with perpetrator), dissociation, and psychiatric comorbidities, while accounting for symptom severity.

METHODS

In total, N = 81 patients with a trauma history (n = 43 with CPTSD; n = 37 with PTSD) underwent diagnostic interviews by trained clinicians and completed measures on CPTSD symptom severity, trauma characteristics, and dissociation (Screening for Complex PTSD; Dissociative Experience Scale Taxon).

RESULTS

Patients with CPTSD reported earlier onset of trauma, more trauma perpetrated by acquaintances or family members, and more comorbidities than those with PTSD, also when accounting for symptom severity. No group differences in chronicity and dissociation were found. Severity of CPTSD was associated with earlier onset, familiarity with perpetrator, more comorbid (affective) disorders, and dissociation in both diagnostic groups.

CONCLUSION

Findings largely confirm earlier research, suggesting that CPTSD is associated with traumatic events that start earlier in life and are perpetrated by acquaintances. Focusing on transdiagnostic symptoms, such as dissociation, may help to detain symptom deterioration. Due to the small sample size, findings need to be interpreted with caution and further research is needed to replicate findings in larger samples. Future research should also elucidate possible working mechanisms besides dissociation, such as emotion dysregulation or negative self-image.

Practical challenges of continuous real-time functional magnetic resonance imaging neurofeedback with multiband accelerated echo-planar imaging and short repetition times

Continuous real-time functional magnetic resonance imaging (fMRI) neurofeedback is gaining increasing scientific attention in clinical neuroscience and may benefit from the short repetition times of modern multiband echoplanar imaging sequences. However, minimizing feedback delay can result in technical challenges. Here, we report a technical problem we experienced during continuous fMRI neurofeedback with multiband echoplanar imaging and short repetition times. We identify the possible origins of this problem, describe our current interim solution and provide openly available workflows and code to other researchers in case they wish to use a similar approach.

Striatal hub of dynamic and stabilized prediction coding in forebrain networks for olfactory reinforcement learning

Identifying the circuits responsible for cognition and understanding their embedded computations is a challenge for neuroscience. We establish here a hierarchical cross-scale approach, from behavioral modeling and fMRI in task-performing mice to cellular recordings, in order to disentangle local network contributions to olfactory reinforcement learning. At mesoscale, fMRI identifies a functional olfactory-striatal network interacting dynamically with higher-order cortices. While primary olfactory cortices respectively contribute only some value components, the downstream olfactory tubercle of the ventral striatum expresses comprehensively reward prediction, its dynamic updating, and prediction error components. In the tubercle, recordings reveal two underlying neuronal populations with non-redundant reward prediction coding schemes. One population collectively produces stabilized predictions as distributed activity across neurons; in the other, neurons encode value individually and dynamically integrate the recent history of uncertain outcomes. These findings validate a cross-scale approach to mechanistic investigations of higher cognitive functions in rodents.

Where and how the brain learns from experience is not fully understood. Here the authors use a hierarchical approach from behavioural modelling to systems fMRI to cellular coding reveals brain mechanisms for history informed updating of future predictions.

Cerebral processing of sharp mechanical pain measured with arterial spin labeling

INTRODUCTION

Arterial spin labeling (ASL) is a functional neuroimaging technique that has been frequently used to investigate acute pain states. A major advantage of ASL as opposed to blood-oxygen-level-dependent functional neuroimaging is its applicability for low-frequency designs. As such, ASL represents an interesting option for studies in which repeating an experimental event would reduce its ecological validity. Whereas most ASL pain studies so far have used thermal stimuli, to our knowledge, no ASL study so far has investigated pain responses to sharp mechanical pain.

METHODS

As a proof of concept, we investigated whether ASL has the sensitivity to detect brain activation within core areas of the nociceptive network in healthy controls following a single stimulation block based on 96 s of mechanical painful stimulation using a blunt blade.

RESULTS

We found significant increases in perfusion across many regions of the nociceptive network such as primary and secondary somatosensory cortices, premotor cortex, posterior insula, inferior parietal cortex, parietal operculum, temporal gyrus, temporo-occipital lobe, putamen, and the cerebellum. Contrary to our hypothesis, we did not find any significant increase within ACC, thalamus, or PFC. Moreover, we were able to detect a significant positive correlation between pain intensity ratings and pain-induced perfusion increase in the posterior insula.

CONCLUSION

We demonstrate that ASL is suited to investigate acute pain in a single event paradigm, although to detect activation within some regions of the nociceptive network, the sensitivity of our paradigm seemed to be limited. Regarding the posterior insula, our paradigm was sensitive enough to detect a correlation between pain intensity ratings and pain-induced perfusion increase. Previous experimental pain studies have proposed that intensity coding in this region may be restricted to thermal stimulation. Our result demonstrates that the posterior insula encodes intensity information for mechanical stimuli as well.

A Strategy to Detect Emerging Non-Delta SARS-CoV-2 Variants with a Monoclonal Antibody Specific for the N501 Spike Residue

Efforts to control SARS-CoV-2 have been challenged by the emergence of variant strains that have important implications for clinical and epidemiological decision making. Four variants of concern (VOCs) have been designated by the Centers for Disease Control and Prevention (CDC), namely, B.1.617.2 (delta), B.1.1.7 (alpha), B.1.351 (beta), and P.1 (gamma), although the last three have been downgraded to variants being monitored (VBMs). VOCs and VBMs have shown increased transmissibility and/or disease severity, resistance to convalescent SARS-CoV-2 immunity and antibody therapeutics, and the potential to evade diagnostic detection. Methods are needed for point-of-care (POC) testing to rapidly identify these variants, protect vulnerable populations, and improve surveillance. Antigen-detection rapid diagnostic tests (Ag-RDTs) are ideal for POC use, but Ag-RDTs that recognize specific variants have not yet been implemented. Here, we describe a mAb (2E8) that is specific for the SARS-CoV-2 spike protein N501 residue. The 2E8 mAb can distinguish the delta VOC from variants with the N501Y meta-signature, which is characterized by convergent mutations that contribute to increased virulence and evasion of host immunity. Among the N501Y-containing mutants formerly designated as VOCs (alpha, beta, and gamma), a previously described mAb, CB6, can distinguish beta from alpha and gamma. When used in a sandwich ELISA, these mAbs sort these important SARS-CoV-2 variants into three diagnostic categories, namely, (1) delta, (2) alpha or gamma, and (3) beta. As delta is currently the predominant variant globally, they will be useful for POC testing to identify N501Y meta-signature variants, protect individuals in high-risk settings, and help detect epidemiological shifts among SARS-CoV-2 variants.

Generation and Characterization of Nanobodies Against Tomato Leaf Curl Sudan Virus

Begomoviruses infect food, fiber, and vegetable crop plants, including tomato, potato, bean, cotton, cucumber, and pumpkin, and damage many economically important crop plants worldwide. Tomato leaf curl Sudan virus (ToLCSDV) is the most widespread tomato-infecting begomovirus in Saudi Arabia. Using phage display technology, this study isolated two camel-derived nanobodies against purified ToLCSDV virions from a library of antigen-binding fragments (VHH or nanobody) of heavy-chain antibodies built from an immunized camel. The isolated nanobodies also cross-reacted with purified tomato yellow leaf curl virus virions and showed significant enzyme-linked immunosorbent assay reactivity with extracts from plants with typical begomovirus infection symptoms. The results can pave the way to developing diagnostics for begomovirus detection, design, and characterization of novel nanomaterials based on virus-like particles, in addition to nanobody-mediated begomovirus resistance in economically important crops, such as tomato, potato, and cucumber.

Differential resting-state patterns across networks are spatially associated with Comt and Trmt2a gene expression patterns in a mouse model of 22q11.2 deletion

Copy number variations (CNV) involving multiple genes are ideal models to study polygenic neuropsychiatric disorders. Since 22q11.2 deletion is regarded as the most important single genetic risk factor for developing schizophrenia, characterizing the effects of this CNV on neural networks offers a unique avenue towards delineating polygenic interactions conferring risk for the disorder. We used a Df(h22q11)/+ mouse model of human 22q11.2 deletion to dissect gene expression patterns that would spatially overlap with differential resting-state functional connectivity (FC) patterns in this model (N = 12 Df(h22q11)/+ mice, N = 10 littermate controls). To confirm the translational relevance of our findings, we analyzed tissue samples from schizophrenia patients and healthy controls using machine learning to explore whether identified genes were co-expressed in humans. Additionally, we employed the STRING protein-protein interaction database to identify potential interactions between genes spatially associated with hypo- or hyper-FC. We found significant associations between differential resting-state connectivity and spatial gene expression patterns for both hypo- and hyper-FC. Two genes, Comt and Trmt2a, were consistently over-expressed across all networks. An analysis of human datasets pointed to a disrupted co-expression of these two genes in the brain in schizophrenia patients, but not in healthy controls. Our findings suggest that COMT and TRMT2A form a core genetic component implicated in differential resting-state connectivity patterns in the 22q11.2 deletion. A disruption of their co-expression in schizophrenia patients points out a prospective cause for the aberrance of brain networks communication in 22q11.2 deletion syndrome on a molecular level.

Protection of Newborn Macaques by Plant-Derived HIV Broadly Neutralizing Antibodies: a Model for Passive Immunotherapy during Breastfeeding

Preventing human immunodeficiency virus (HIV) infection in newborns by vertical transmission remains an important unmet medical need in resource-poor areas where antiretroviral therapy (ART) is not available and mothers and infants cannot be treated prepartum or during the breastfeeding period. In the present study, the protective efficacy of the potent HIV-neutralizing antibodies PGT121 and VRC07-523, both produced in plants, were assessed in a multiple-SHIV (simian-human immunodeficiency virus)-challenge breastfeeding macaque model. Newborn macaques received either six weekly subcutaneous injections with PGT121 alone or as a cocktail of PGT121-LS plus VRC07-523-LS injected three times every 2 weeks. Viral challenge with SHIVSF162P3 was twice weekly over 5.5 weeks using 11 exposures. Despite the transient presence of plasma viral RNA either immediately after the first challenge or as single-point blips, the antibodies prevented a productive infection in all babies with no sustained plasma viremia, compared to viral loads ranging from 103 to 5 × 108 virions/ml in four untreated controls. No virus was detected in peripheral blood mononuclear cells (PBMCs), and only 3 of 159 tissue samples were weakly positive in the treated babies. Newborn macaques proved to be immunocompetent, producing transient anti-Env antibodies and anti-drug antibody (ADA), which were maintained in the circulation after passive broadly neutralizing antibody clearance. ADA responses were directed to the IgG1 Fc CH2-CH3 domains, which has not been observed to date in adult monkeys passively treated with PGT121 or VRC01. In addition, high levels of VRC07-523 anti-idiotypic antibodies in the circulation of one newborn was concomitant with the rapid elimination of VRC07. Plant-expressed antibodies show promise as passive immunoprophylaxis in a breastfeeding model in newborns. IMPORTANCE Plant-produced human neutralizing antibody prophylaxis is highly effective in preventing infection in newborn monkeys during repeated oral exposure, modeling virus in breastmilk, and offers advantages in cost of production and safety. These findings raise the possibility that anti-Env antibodies may contribute to the control of viral replication in this newborn model and that the observed immune responsiveness may be driven by the long-lived presence of immune complexes.

[Cross-sectoral therapeutic concepts and innovative technologies: new opportunities for the treatment of patients with mental disorders]

Mental disorders are widespread and a major public health problem. The risk of developing a mental disorder at some point in life is around 40%. Therefore, mental disorders are among the most common diseases. Despite the introduction of newer psychotropic drugs, disorder-specific psychotherapy and stimulation techniques, many of those affected still show insufficient symptom remission and a chronic course of the disorder. Conceptual and technological progress in recent years has enabled a new, more flexible and personalized form of mental health care. Both the traditional therapeutic concepts and newer decentralized, modularly structured, track units, together with innovative digital technologies, will offer individualized therapeutic options in order to alleviate symptoms and improve quality of life of patients with mental illnesses. The primary goal of closely combining inpatient care concepts with innovative technologies is to provide comprehensive therapy and aftercare concepts for all individual needs of patients with mental disorders. Last but not least, this also ensures that specialist psychiatric treatment is available regardless of location. In twenty-first century psychiatry, modern care structures must be effectively linked to the current dynamics of digital transformation. This narrative review is dedicated to the theoretical and practical aspects of a cross-sectoral treatment system combined with innovative digital technologies in the psychiatric-psychotherapeutic field. The authors aim to illuminate these therapy modalities using the example of the Central Institute of Mental Health in Mannheim.

Cortical Glutamate and GABA Changes During Early Abstinence in Alcohol Dependence and Their Associations With Benzodiazepine Medication

In this report, we present cross-sectional and longitudinal findings from single-voxel MEGA-PRESS MRS of GABA as well as Glu, and Glu + glutamine (Glx) concentrations in the ACC of treatment-seeking alcohol-dependent patients (ADPs) during detoxification (first 2 weeks of abstinence). The focus of this study was to examine whether the amount of benzodiazepine administered to treat withdrawal symptoms was associated with longitudinal changes in Glu, Glx, and GABA. The tNAA levels served as an internal quality reference; in agreement with the vast majority of previous reports, these levels were initially decreased and normalized during the course of abstinence in ADPs. Our results on Glu and Glx support hyperglutamatergic functioning during alcohol withdrawal, by showing higher ACC Glu and Glx levels on the first day of detoxification in ADPs. Withdrawal severity is reflected in cumulative benzodiazepine requirements throughout the withdrawal period. The importance of withdrawal severity for the study of GABA and Glu changes in early abstinence is emphasized by the benzodiazepine-dependent Glu, Glx, and GABA changes observed during the course of abstinence.

COVID-19 vaccine development and a potential nanomaterial path forward

The COVID-19 pandemic has infected millions of people with no clear signs of abatement owing to the high prevalence, long incubation period and lack of established treatments or vaccines. Vaccines are the most promising solution to mitigate new viral strains. The genome sequence and protein structure of the 2019-novel coronavirus (nCoV or SARS-CoV-2) were made available in record time, allowing the development of inactivated or attenuated viral vaccines along with subunit vaccines for prophylaxis and treatment. Nanotechnology benefits modern vaccine design since nanomaterials are ideal for antigen delivery, as adjuvants, and as mimics of viral structures. In fact, the first vaccine candidate launched into clinical trials is an mRNA vaccine delivered via lipid nanoparticles. To eradicate pandemics, present and future, a successful vaccine platform must enable rapid discovery, scalable manufacturing and global distribution. Here, we review current approaches to COVID-19 vaccine development and highlight the role of nanotechnology and advanced manufacturing.

Interactive tool to create adjustable anatomical atlases for mouse brain imaging

Objective

Brain atlases are important research tools enabling researchers to focus their investigations on specific anatomically defined brain regions and are used in many MRI applications, e.g. in fMRI, morphometry, whole brain spectroscopy, et cetera. Despite their extensive use and numerous versions they usually consist of predefined rigid brain regions with a given level of detail often degrading them to a non-ideal tool in special research topics.

Result

To overcome this intrinsic weakness we present a graphical user interface application which allows researchers to easily create mouse brain atlases with an adjustable user-defined level of detail and coverage to match specific research questions.

Comparison of Multivendor Single-Voxel MR Spectroscopy Data Acquired in Healthy Brain at 26 Sites

Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better understand sources of the total variance in quantified metabolite levels. Purpose To compare multisite quantitative brain MR spectroscopy data acquired in healthy participants at 26 sites by using the vendor-supplied single-voxel point-resolved spectroscopy (PRESS) sequence. Materials and Methods An MR spectroscopy protocol to acquire short-echo-time PRESS data from the midparietal region of the brain was disseminated to 26 research sites operating 3.0-T MR scanners from three different vendors. In this prospective study, healthy participants were scanned between July 2016 and December 2017. Data were analyzed by using software with simulated basis sets customized for each vendor implementation. The proportion of total variance attributed to vendor-, site-, and participant-related effects was estimated by using a linear mixed-effects model. P values were derived through parametric bootstrapping of the linear mixed-effects models (denoted Pboot). Results In total, 296 participants (mean age, 26 years ± 4.6; 155 women and 141 men) were scanned. Good-quality data were recorded from all sites, as evidenced by a consistent linewidth of N-acetylaspartate (range, 4.4-5.0 Hz), signal-to-noise ratio (range, 174-289), and low Cramér-Rao lower bounds (≤5%) for all of the major metabolites. Among the major metabolites, no vendor effects were found for levels of myo-inositol (Pboot > .90), N-acetylaspartate and N-acetylaspartylglutamate (Pboot = .13), or glutamate and glutamine (Pboot = .11). Among the smaller resonances, no vendor effects were found for ascorbate (Pboot = .08), aspartate (Pboot > .90), glutathione (Pboot > .90), or lactate (Pboot = .28). Conclusion Multisite multivendor single-voxel MR spectroscopy studies performed at 3.0 T can yield results that are coherent across vendors, provided that vendor differences in pulse sequence implementation are accounted for in data analysis. However, the site-related effects on variability were more profound and suggest the need for further standardization of spectroscopic protocols. © RSNA, 2020 Online supplemental material is available for this article.

The influence of ketamine's repeated treatment on brain topology does not suggest an antidepressant efficacy

As ketamine is increasingly used as an effective antidepressant with rapid action, sustaining its short-lived efficacy over a longer period of time using a schedule of repeated injections appears as an option. An open question is whether repeated and single administrations would affect convergent neurocircuits. We used a combination of one of the most robust animal models of depression with high-field neuroimaging to perform a whole-brain delineation of functional mechanisms underlying ketamine's effects. Rats from two genetic strains, depressive-like and resilient, received seven treatments of 10 mg/kg S-ketamine (N = 14 depressive-like, N = 11 resilient) or placebo (N = 12 depressive-like, N = 10 resilient) and underwent resting-state functional magnetic resonance imaging. Using graph theoretical models of brain networks, we compared effects of repeated ketamine with those of single administration from a separate dataset of our previous study. Compared to single treatment, repeated ketamine evoked strain-specific brain network randomization, resembling characteristics of the depressive-like strain and patients. Several affected regions belonged to the auditory, visual, and motor circuitry, hinting at possible cumulative side effects. Finally, when compared to saline, repeated ketamine affected only a few local topological properties and had no effects on global properties. In combination with the lack of clear differences compared to placebo, our findings point toward an inefficacy of ketamine's long-term administration on brain topology, making questionable the postulated effect of repeated administration and being consistent with the recently reported absence of repeated ketamine's antidepressant efficacy in several placebo-controlled studies.

Plant cell packs: a scalable platform for recombinant protein production and metabolic engineering

Industrial plant biotechnology applications include the production of sustainable fuels, complex metabolites and recombinant proteins, but process development can be impaired by a lack of reliable and scalable screening methods. Here, we describe a rapid and versatile expression system which involves the infusion of Agrobacterium tumefaciens into three-dimensional, porous plant cell aggregates deprived of cultivation medium, which we have termed plant cell packs (PCPs). This approach is compatible with different plant species such as Nicotiana tabacum BY2, Nicotiana benthamiana or Daucus carota and 10-times more effective than transient expression in liquid plant cell culture. We found that the expression of several proteins was similar in PCPs and intact plants, for example, 47 and 55 mg/kg for antibody 2G12 expressed in BY2 PCPs and N. tabacum plants respectively. Additionally, the expression of specific enzymes can either increase the content of natural plant metabolites or be used to synthesize novel small molecules in the PCPs. The PCP method is currently scalable from a microtiter plate format suitable for high-throughput screening to 150-mL columns suitable for initial product preparation. It therefore combined the speed of transient expression in plants with the throughput of microbial screening systems. Plant cell packs therefore provide a convenient new platform for synthetic biology approaches, metabolic engineering and conventional recombinant protein expression techniques that require the multiplex analysis of several dozen up to hundreds of constructs for efficient product and process development.

Differences between ketamine's short-term and long-term effects on brain circuitry in depression

Ketamine acts as a rapid clinical antidepressant at 25 min after injection with effects sustained for 7 days. As dissociative effects emerging acutely after injection are not entirely discernible from therapeutic action, we aimed to dissect the differences between short-term and long-term response to ketamine to elucidate potential imaging biomarkers of ketamine's antidepressant effect. We used a genetical model of depression, in which we bred depressed negative cognitive state (NC) and non-depressed positive cognitive state (PC) rat strains. Four parallel rat groups underwent stress-escape testing and a week later received either S-ketamine (12 NC, 13 PC) or saline (12 NC, 12 PC). We acquired resting-state functional magnetic resonance imaging time series before injection and at 30 min and 48 h after injection. Graph analysis was used to calculate brain network properties. We identified ketamine's distinct action over time in a qualitative manner. The rapid response entailed robust and strain-independent topological modifications in cognitive, sensory, emotion, and reward-related circuitry, including regions that exhibited correlation of connectivity metrics with depressive behavior, and which could explain ketamine's dissociative and antidepressant properties. At 48 h ketamine had mainly strain-specific action normalizing habenula, midline thalamus, and hippocampal connectivity measures in depressed rats. As these nodes mediate cognitive flexibility impaired in depression, action within this circuitry presumably reflects ketamine's procognitive effects induced only in depressed patients. This finding is especially valid, as our model represents cognitive aspects of depression. These empirically defined circuits explain ketamine's distinct action over time and might serve as translational imaging correlates of antidepressant response in preclinical testing.

Big GABA II: Water-referenced edited MR spectroscopy at 25 research sites

Accurate and reliable quantification of brain metabolites measured in vivo using ¹H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological challenge. In this study, spectrally edited γ-aminobutyric acid (GABA) MRS data were analyzed and GABA levels were quantified relative to an internal tissue water reference. Data from 284 volunteers scanned across 25 research sites were collected using GABA+ (GABA + co-edited macromolecules (MM)) and MM-suppressed GABA editing. The unsuppressed water signal from the volume of interest was acquired for concentration referencing. Whole-brain T₁-weighted structural images were acquired and segmented to determine gray matter, white matter and cerebrospinal fluid voxel tissue fractions. Water-referenced GABA measurements were fully corrected for tissue-dependent signal relaxation and water visibility effects. The cohort-wide coefficient of variation was 17% for the GABA + data and 29% for the MM-suppressed GABA data. The mean within-site coefficient of variation was 10% for the GABA + data and 19% for the MM-suppressed GABA data. Vendor differences contributed 53% to the total variance in the GABA + data, while the remaining variance was attributed to site- (11%) and participant-level (36%) effects. For the MM-suppressed data, 54% of the variance was attributed to site differences, while the remaining 46% was attributed to participant differences. Results from an exploratory analysis suggested that the vendor differences were related to the unsuppressed water signal acquisition. Discounting the observed vendor-specific effects, water-referenced GABA measurements exhibit similar levels of variance to creatine-referenced GABA measurements. It is concluded that quantification using internal tissue water referencing is a viable and reliable method for the quantification of in vivo GABA levels.

CRISPR/Cas9-mediated knockout of six glycosyltransferase genes in Nicotiana benthamiana for the production of recombinant proteins lacking β-1,2-xylose and core α-1,3-fucose

Plants offer fast, flexible and easily scalable alternative platforms for the production of pharmaceutical proteins, but differences between plant and mammalian N-linked glycans, including the presence of β-1,2-xylose and core α-1,3-fucose residues in plants, can affect the activity, potency and immunogenicity of plant-derived proteins. Nicotiana benthamiana is widely used for the transient expression of recombinant proteins so it is desirable to modify the endogenous N-glycosylation machinery to allow the synthesis of complex N-glycans lacking β-1,2-xylose and core α-1,3-fucose. Here, we used multiplex CRISPR/Cas9 genome editing to generate N. benthamiana production lines deficient in plant-specific α-1,3-fucosyltransferase and β-1,2-xylosyltransferase activity, reflecting the mutation of six different genes. We confirmed the functional gene knockouts by Sanger sequencing and mass spectrometry-based N-glycan analysis of endogenous proteins and the recombinant monoclonal antibody 2G12. Furthermore, we compared the CD64-binding affinity of 2G12 glycovariants produced in wild-type N. benthamiana, the newly generated FX-KO line, and Chinese hamster ovary (CHO) cells, confirming that the glyco-engineered antibody performed as well as its CHO-produced counterpart.

The affinity of antipsychotic drugs to dopamine and serotonin 5-HT2 receptors determines their effects on prefrontal-striatal functional connectivity

One of the major challenges of cross-species translation in psychiatry is the identification of quantifiable brain phenotypes linked to drug efficacy and/or side effects. A measure that has received increasing interest is the effect of antipsychotic drugs on resting-state functional connectivity (FC) in magnetic resonance imaging. However, quantitative comparisons of antipsychotic drug-induced alterations of FC patterns are missing. Consideration of receptor binding affinities provides a means for the effects of antipsychotic drugs on extended brain networks to be related directly to their molecular mechanism of action. Therefore, we examined the relationship between the affinities of three second-generation antipsychotics (amisulpride, risperidone and olanzapine) to dopamine and serotonin receptors and FC patterns related to the prefrontal cortex (PFC) and striatum in Sprague-Dawley rats. FC of the relevant regions was quantified by correlation coefficients and local network properties. Each drug group (32 animals per group) was subdivided into three dose groups and a vehicle control group. A linear relationship was discovered for the mid-dose of antipsychotic compounds, with stronger affinity to serotonin 5-HT_2A, 5-HT_2C and 5-HT_1A receptors and decreased affinity to D₃ receptors associated with increased prefrontal-striatal FC (p = 0.0004, r² = 0.46; p = 0.004, r² = 0.33; p = 0.002, r² = 0.37; p = 0.02, r² = 0.22, respectively). Interestingly, no correlation was observed for the low and high dose groups, and for D₂ receptors. Our results indicate that drug-induced FC patterns may be linked to antipsychotic mechanism of action on the molecular level and suggest the technique's value for drug development, especially if our results are extended to a larger number of antipsychotics.

Neural Mechanisms of Early-Life Social Stress as a Developmental Risk Factor for Severe Psychiatric Disorders

BACKGROUND

To explore the domain-general risk factor of early-life social stress in mental illness, rearing rodents in persistent postweaning social isolation has been established as a widely used animal model with translational relevance for neurodevelopmental psychiatric disorders such as schizophrenia. Although changes in resting-state brain connectivity are a transdiagnostic key finding in neurodevelopmental diseases, a characterization of imaging correlates elicited by early-life social stress is lacking.

METHODS

We performed resting-state functional magnetic resonance imaging of postweaning social isolation rats (N = 23) 9 weeks after isolation. Addressing well-established transdiagnostic connectivity changes of psychiatric disorders, we focused on altered frontal and posterior connectivity using a seed-based approach. Then, we examined changes in regional network architecture and global topology using graph theoretical analysis.

RESULTS

Seed-based analyses demonstrated reduced functional connectivity in frontal brain regions and increased functional connectivity in posterior brain regions of postweaning social isolation rats. Graph analyses revealed a shift of the regional architecture, characterized by loss of dominance of frontal regions and emergence of nonfrontal regions, correlating to our behavioral results, and a reduced modularity in isolation-reared rats.

CONCLUSIONS

Our result of functional connectivity alterations in the frontal brain supports previous investigations postulating social neural circuits, including prefrontal brain regions, as key pathways for risk for mental disorders arising through social stressors. We extend this knowledge by demonstrating more widespread changes of brain network organization elicited by early-life social stress, namely a shift of hubness and dysmodularity. Our results highly resemble core alterations in neurodevelopmental psychiatric disorders such as schizophrenia, autism, and attention-deficit/hyperactivity disorder in humans.

Longitudinal Structural and Functional Brain Network Alterations in a Mouse Model of Neuropathic Pain

Neuropathic pain affects multiple brain functions, including motivational processing. However, little is known about the structural and functional brain changes involved in the transition from an acute to a chronic pain state. Here we combined behavioral phenotyping of pain thresholds with multimodal neuroimaging to longitudinally monitor changes in brain metabolism, structure and connectivity using the spared nerve injury (SNI) mouse model of chronic neuropathic pain. We investigated stimulus-evoked pain responses prior to SNI surgery, and one and twelve weeks following surgery. A progressive development and potentiation of stimulus-evoked pain responses (cold and mechanical allodynia) were detected during the course of pain chronification. Voxel-based morphometry demonstrated striking decreases in volume following pain induction in all brain sites assessed - an effect that reversed over time. Similarly, all global and local network changes that occurred following pain induction disappeared over time, with two notable exceptions: the nucleus accumbens, which played a more dominant role in the global network in a chronic pain state and the prefrontal cortex and hippocampus, which showed lower connectivity. These changes in connectivity were accompanied by enhanced glutamate levels in the hippocampus, but not in the prefrontal cortex. We suggest that hippocampal hyperexcitability may contribute to alterations in synaptic plasticity within the nucleus accumbens, and to pain chronification.

Antagonism at the NR2B subunit of NMDA receptors induces increased connectivity of the prefrontal and subcortical regions regulating reward behavior

RATIONALE

Evidence indicates that ketamine's rapid antidepressant efficacy likely results from its antagonism of NR2B-subunit-containing NMDA receptors (NMDAR). Since ketamine equally blocks NR2A- and NR2B-containing NMDAR, and has affinity to other receptors, NR2B-selective drugs might have improved therapeutic efficiency and side effect profile.

OBJECTIVES

We aimed to compare the effects of (S)-ketamine and two different types of NR2B-selective antagonists on functional brain networks in rats, in order to find common circuits, where their effects intersect, and that might explain their antidepressant action.

METHODS

The experimental design comprised four parallel groups of rats (N = 37), each receiving (S)-Ketamine, CP-101,606, Ro 25-6981 or saline. After compound injection, we acquired resting-state functional magnetic resonance imaging time series. We used graph theoretical approach to calculate brain network properties.

RESULTS

Ketamine and CP-101,606 diminished the global clustering coefficient and small-worldness index. At the nodal level, all compounds induced increased connectivity of the regions mediating reward and cognitive aspects of emotional processing, such as ventromedial prefrontal cortex, septal nuclei, and nucleus accumbens. The dorsal hippocampus and regions involved in sensory processing and aversion, such as superior and inferior colliculi, exhibited an opposite effect.

CONCLUSIONS

The effects common to ketamine and NR2B-selective compounds were localized to the same brain regions as those reported in depression, but in the opposite direction. The upregulation of the reward circuitry might partially underlie the antidepressant and anti-anhedonic effects of the antagonists and could potentially serve as a translational imaging phenotype for testing putative antidepressants, especially those targeting the NR2B receptor subtype.

Lateral habenula perturbation reduces default-mode network connectivity in a rat model of depression

Hyperconnectivity of the default-mode network (DMN) is one of the most widely replicated neuroimaging findings in major depressive disorder (MDD). Further, there is growing evidence for a central role of the lateral habenula (LHb) in the pathophysiology of MDD. There is preliminary neuroimaging evidence linking LHb and the DMN, but no causal relationship has been shown to date. We combined optogenetics and functional magnetic resonance imaging (fMRI), to establish a causal relationship, using an animal model of treatment-resistant depression, namely Negative Cognitive State rats. First, an inhibitory light-sensitive ion channel was introduced into the LHb by viral transduction. Subsequently, laser stimulation was performed during fMRI acquisition on a 9.4 Tesla animal scanner. Neural activity and connectivity were assessed, before, during and after laser stimulation. We observed a connectivity decrease in the DMN following laser-induced LHb perturbation. Our data indicate a causal link between LHb downregulation and reduction in DMN connectivity. These findings may advance our mechanistic understanding of LHb inhibition, which had previously been identified as a promising therapeutic principle, especially for treatment-resistant depression.

Big GABA: Edited MR spectroscopy at 24 research sites

Magnetic resonance spectroscopy (MRS) is the only biomedical imaging method that can noninvasively detect endogenous signals from the neurotransmitter γ-aminobutyric acid (GABA) in the human brain. Its increasing popularity has been aided by improvements in scanner hardware and acquisition methodology, as well as by broader access to pulse sequences that can selectively detect GABA, in particular J-difference spectral editing sequences. Nevertheless, implementations of GABA-edited MRS remain diverse across research sites, making comparisons between studies challenging. This large-scale multi-vendor, multi-site study seeks to better understand the factors that impact measurement outcomes of GABA-edited MRS. An international consortium of 24 research sites was formed. Data from 272 healthy adults were acquired on scanners from the three major MRI vendors and analyzed using the Gannet processing pipeline. MRS data were acquired in the medial parietal lobe with standard GABA+ and macromolecule- (MM-) suppressed GABA editing. The coefficient of variation across the entire cohort was 12% for GABA+ measurements and 28% for MM-suppressed GABA measurements. A multilevel analysis revealed that most of the variance (72%) in the GABA+ data was accounted for by differences between participants within-site, while site-level differences accounted for comparatively more variance (20%) than vendor-level differences (8%). For MM-suppressed GABA data, the variance was distributed equally between site- (50%) and participant-level (50%) differences. The findings show that GABA+ measurements exhibit strong agreement when implemented with a standard protocol. There is, however, increased variability for MM-suppressed GABA measurements that is attributed in part to differences in site-to-site data acquisition. This study's protocol establishes a framework for future methodological standardization of GABA-edited MRS, while the results provide valuable benchmarks for the MRS community.

Intranasal oxytocin reduces provoked symptoms in female patients with posttraumatic stress disorder despite exerting sympathomimetic and positive chronotropic effects in a randomized controlled trial

BACKGROUND

Posttraumatic stress disorder (PTSD) is a severe psychiatric disease accompanied by neuroendocrine changes such as adrenergic overdrive and hence an elevated cardiovascular morbidity. Current pharmacotherapeutic options for PTSD are less than suboptimal, necessitating the development of PTSD-specific drugs. Although the neuropeptide oxytocin has been repeatedly suggested to be effective in PTSD treatment, there are, to our knowledge, only three studies that have assessed its efficacy on the intensity of PTSD symptoms in PTSD patients - among them one symptom provocation study in male veterans.

METHODS

To evaluate for the first time how oxytocin influences the intensity of provoked PTSD symptoms and, furthermore, cardiac control in female PTSD patients, we assessed their psychic and cardiac response to trauma-script exposure with and without oxytocin pretreatment in a double-blind randomized placebo-controlled study. We used a within-subject design to study 35 female PTSD patients who received oxytocin and placebo in a 2-week interval. Furthermore, we performed a small pilot study to get an idea of the relation of the stress-modulated endogenous oxytocin levels and heart rate - we correlated oxytocin serum levels with the heart rate of 10 healthy individuals before and after exposure to the Trier Social Stress Test (TSST).

RESULTS

Intranasal oxytocin treatment was followed by a reduction of provoked total PTSD symptoms, in particular of avoidance, and by an elevation in baseline and maximum heart rate together with a drop in the pre-ejection period, a marker for sympathetic cardiac control. Furthermore, we found a positive correlation between endogenous oxytocin levels and heart rate both before and after TSST challenge in healthy control subjects.

CONCLUSIONS

This study provides the first evidence that oxytocin treatment reduces the intensity of provoked PTSD symptoms in female PTSD patients. The small size of both samples and the heterogeneity of the patient sample restrict the generalizability of our findings. Future studies have to explore the gender dependency and the tolerability of the oxytocin-mediated increase in heart rate. This randomized controlled trial was retrospectively registered at the German Trials Register (DRKS00009399) on the 02 October 2015.

Cetuximab Resistance in Head and Neck Cancer Is Mediated by EGFR-K521 Polymorphism

Head and neck squamous cell carcinomas (HNSCC) exhibiting resistance to the EGFR-targeting drug cetuximab poses a challenge to their effective clinical management. Here, we report a specific mechanism of resistance in this setting based upon the presence of a single nucleotide polymorphism encoding EGFR-K₅₂₁ (K-allele), which is expressed in >40% of HNSCC cases. Patients expressing the K-allele showed significantly shorter progression-free survival upon palliative treatment with cetuximab plus chemotherapy or radiation. In several EGFR-mediated cancer models, cetuximab failed to inhibit downstream signaling or to kill cells harboring a high K-allele frequency. Cetuximab affinity for EGFR-K₅₂₁ was reduced slightly, but ligand-mediated EGFR activation was intact. We found a lack of glycan sialyation on EGFR-K₅₂₁ that associated with reduced protein stability, suggesting a structural basis for reduced cetuximab efficacy. CetuGEX, an antibody with optimized Fc glycosylation targeting the same epitope as cetuximab, restored HNSCC sensitivity in a manner associated with antibody-dependent cellular cytotoxicity rather than EGFR pathway inhibition. Overall, our results highlight EGFR-K₅₂₁ expression as a key mechanism of cetuximab resistance to evaluate prospectively as a predictive biomarker in HNSCC patients. Further, they offer a preclinical rationale for the use of ADCC-optimized antibodies to treat tumors harboring this EGFR isoform. Cancer Res; 77(5); 1188-99. ©2016 AACR.

ACC GABA levels are associated with functional activation and connectivity in the fronto-striatal network during interference inhibition in patients with borderline personality disorder

Impulsivity often develops from disturbed inhibitory control, a function mainly regulated by γ-Aminobutyric acid (GABA) levels in the anterior cingulate cortex (ACC) and the fronto-striatal system. In this study, we combined MRS GABA measurements and fMRI to investigate neurochemical and neurofunctional correlates of interference inhibition, further emphasizing the direct relationship between those two systems, as well as their relations to impulsivity in patients with BPD. In addition to BOLD activation, task-dependent functional connectivity was assessed by a generalized psychophysiological interactions approach. Full factorial analyses were performed via SPM to examine the main effect (within-group associations) as well as the interaction term (group differences in the association slope). The UPPS scales were used to evaluate impulsivity traits. Compared to healthy controls (HCs), BPD patients exhibited significantly less ACC-caudate functional connectivity during interference inhibition. ACC GABA levels in BPD patients but not in HCs were positively related to the magnitude of activation in several fronto-striatal regions (e.g. ACC, frontal regions, putamen, caudate,) and the strength of ACC-caudate functional connectivity during interference inhibition. The strength of the correlations of GABA with connectivity significantly differs between the two groups. Moreover, among all the UPPS impulsivity subscales, UPPS sensation seeking in the BPD group was related to GABA and was also negatively related to the task-dependent BOLD activation and functional connectivity in the fronto-striatal network. Finally, mediation analyses revealed that the magnitude of activation in the caudate and the strength of ACC-caudate functional connectivity mediated the relationship between ACC GABA levels and UPPS sensation seeking in patients with BPD. Our findings suggest a disconnectivity of the fronto-striatal network in BPD patients during interference inhibition, particularly for patients with higher impulsivity. The ACC GABAergic system seems to play a crucial role in regulating regional BOLD activations and functional connectivity in this network, which are further associated with impulsive sensation seeking in BPD.

SNAP-Tag Technology: A Useful Tool To Determine Affinity Constants and Other Functional Parameters of Novel Antibody Fragments

Antibody derivatives, such as the single chain fragment variable (scFv), can be developed as diagnostic and therapeutic tools in cancer research, especially in the form of fusion proteins. Such derivatives are easier to produce and modify than monoclonal antibodies (mAbs) and achieve better tissue/tumor penetration. The genetic modification of scFvs is also much more straightforward than the challenging chemical modification of mAbs. Therefore, we constructed two scFvs derived from the approved monoclonal antibodies cetuximab (scFv2112) and panitumumab (scFv1711), both of which are specific for the epidermal growth factor receptor (EGFR), a well-characterized solid tumor antigen. Both scFvs were genetically fused to the SNAP-tag, an engineered version of the human DNA repair enzyme O(6)-alkylguanine DNA alkyltransferase that allows the covalent coupling of benzylguanine (BG)-modified substrates such as fluorescent dyes. The SNAP-tag achieves controllable and irreversible protein modification and is an important tool for experimental studies in vitro and in vivo. The affinity constant of a scFv is a key functional parameter, especially in the context of a fusion protein. Therefore, we developed a method to define the affinity constants of scFv-SNAP fusion proteins by surface plasmon resonance (SPR) spectroscopy. We could confirm that both scFvs retained their functionality after fusion to the SNAP-tag in a variety of procedures and assays, including ELISA, flow cytometry, and confocal microscopy. The experimental procedures described herein, and the new protocol for affinity determination by SPR spectroscopy, are suitable for the preclinical evaluation of diverse antibody formats and derivatives.

Protection against SHIV Challenge by Subcutaneous Administration of the Plant-Derived PGT121 Broadly Neutralizing Antibody in Macaques

Intravascular delivery of broadly neutralizing antibodies (bnAbs) has shown promise for prevention and treatment of HIV infection. However, multiple IV administrations in geographic locations with poor accessibility to medical care have practical limitations. We have assessed the efficacy of plant-derived PGT121 delivered subcutaneously (SC) against pre-and post-intravaginal challenge using a rigorous SHIV-SF162P3 macaque protection model. SC administered PGT121 exhibited a longer serum half-life than IV administration and was more consistent than intramuscular delivery. A dose of 3.5mg/kg PGT121 prevented infection at a minimum ID50 neutralization titer of 1:295 while 5mg/kg protected five of six macaques when delivered immediately post-challenge. These results suggest the utility of plant-derived bnAbs delivered SC for HIV prevention.

Overcoming low yields of plant-made antibodies by a protein engineering approach

The commercial development of plant-based antibody production platforms is often limited by low and variable yields, but little is known about the factors that affect antibody accumulation during and after translation. Here, we present a strategy to identify yield-limiting regions in the transcript and protein. We exchanged variable heavy chain (VH) domain sequences between two human antibodies at structurally conserved positions, thus creating ten chimeric VH domains containing sequences from M12 (∼1000 μg/g leaf fresh weight [FW]) and 4E10 (∼100 μg/g FW). After transient expression in Nicotiana benthamiana leaves, we measured mRNA and protein levels by quantitative real-time PCR and surface plasmon resonance spectroscopy, respectively. Transcript levels were similar for all constructs, but antibody levels ranged from ∼250 μg/g to over 2000 μg/g FW. Analysis of the expression levels showed that: i) 4E10 yields were only marginally increased by suppression of post-transcriptional gene silencing; ii) the CDR3 of 4E10 contains a protease site; and iii) a bipartite, yield-limiting region exists in the CDR2/CDR3. Our findings highlight the strong impact of cotranslational and posttranslational events on antibody yields and show that protein engineering is a powerful tool that can be used to overcome the remaining limitations affecting antibody production in plants.

Putting the Spotlight Back on Plant Suspension Cultures

Plant cell suspension cultures have several advantages that make them suitable for the production of recombinant proteins. They can be cultivated under aseptic conditions using classical fermentation technology, they are easy to scale-up for manufacturing, and the regulatory requirements are similar to those established for well-characterized production systems based on microbial and mammalian cells. It is therefore no surprise that taliglucerase alfa (Elelyso®)-the first licensed recombinant pharmaceutical protein derived from plants-is produced in plant cell suspension cultures. But despite this breakthrough, plant cells are still largely neglected compared to transgenic plants and the more recent plant-based transient expression systems. Here, we revisit plant cell suspension cultures and highlight recent developments in the field that show how the rise of plant cells parallels that of Chinese hamster ovary cells, currently the most widespread and successful manufacturing platform for biologics. These developments include medium optimization, process engineering, statistical experimental designs, scale-up/scale-down models, and process analytical technologies. Significant yield increases for diverse target proteins will encourage a gold rush to adopt plant cells as a platform technology, and the first indications of this breakthrough are already on the horizon.

Impulsivity and Aggression in Female BPD and ADHD Patients: Association with ACC Glutamate and GABA Concentrations

Borderline personality disorder (BPD) and attention-deficit-hyperactivity disorder (ADHD) are both characterized by high impulsivity and difficulties in controlling anger and aggression. In BPD, comorbid ADHD may further increase impulsivity. For both disorders, altered MR spectroscopy levels of the neurotransmitters glutamate and GABA as well as some correlations with impulsivity were previously reported. The objective of this study was to investigate the neurotransmitters glutamate and GABA in relation to impulsivity and aggression as expressed in the anterior cingulate cortex (ACC) in groups of female patients with BPD and ADHD, respectively. Associations of glutamate and GABA levels with further BPD (symptom severity) and ADHD aspects (hyperactivity and inattention) were exploratively evaluated. 1H MR spectra were acquired at 3T to determine glutamate to total creatine ratios (Glu/tCr) and GABA levels from the ACC in a BPD group (n=26), an ADHD group (n=22), and a healthy control (HC) group (n=30); all participants were females. Both patient groups showed higher scores on self-reported impulsivity, anger, and aggression compared with HCs. ACC GABA levels were significantly lower in ADHD than HC. Although measures of impulsivity were positively related to glutamate and negatively to GABA, for aggression only a negative correlation with GABA could be demonstrated. These data provide human in vivo evidence for the role of ACC Glu/tCr and GABA in impulsivity and aggression. If distinct associations of Glu/tCr and GABA for BPD and ADHD can be confirmed in future studies, this might yield implications for more specific pharmacological treatments.

Regulatory approval and a first-in-human phase I clinical trial of a monoclonal antibody produced in transgenic tobacco plants

Although plant biotechnology has been widely investigated for the production of clinical-grade monoclonal antibodies, no antibody products derived from transgenic plants have yet been approved by pharmaceutical regulators for clinical testing. In the Pharma-Planta project, the HIV-neutralizing human monoclonal antibody 2G12 was expressed in transgenic tobacco (Nicotiana tabacum). The scientific, technical and regulatory demands of good manufacturing practice (GMP) were addressed by comprehensive molecular characterization of the transgene locus, confirmation of genetic and phenotypic stability over several generations of transgenic plants, and by establishing standard operating procedures for the creation of a master seed bank, plant cultivation, harvest, initial processing, downstream processing and purification. The project developed specifications for the plant-derived antibody (P2G12) as an active pharmaceutical ingredient (API) based on (i) the guidelines for the manufacture of monoclonal antibodies in cell culture systems; (ii) the draft European Medicines Agency Points to Consider document on quality requirements for APIs produced in transgenic plants; and (iii) de novo guidelines developed with European national regulators. From the resulting process, a GMP manufacturing authorization was issued by the competent authority in Germany for transgenic plant-derived monoclonal antibodies for use in a phase I clinical evaluation. Following preclinical evaluation and ethical approval, a clinical trial application was accepted by the UK national pharmaceutical regulator. A first-in-human, double-blind, placebo-controlled, randomized, dose-escalation phase I safety study of a single vaginal administration of P2G12 was carried out in healthy female subjects. The successful completion of the clinical trial marks a significant milestone in the commercial development of plant-derived pharmaceutical proteins.

From gene to harvest: insights into upstream process development for the GMP production of a monoclonal antibody in transgenic tobacco plants

The EU Sixth Framework Programme Integrated Project 'Pharma-Planta' developed an approved manufacturing process for recombinant plant-made pharmaceutical proteins (PMPs) using the human HIV-neutralizing monoclonal antibody 2G12 as a case study. In contrast to the well-established Chinese hamster ovary platform, which has been used for the production of therapeutic antibodies for nearly 30 years, only draft regulations were initially available covering the production of recombinant proteins in transgenic tobacco plants. Whereas recombinant proteins produced in animal cells are secreted into the culture medium during fermentation in bioreactors, intact plants grown under nonsterile conditions in a glasshouse environment provide various 'plant-specific' regulatory and technical challenges for the development of a process suitable for the acquisition of a manufacturing licence for clinical phase I trials. During upstream process development, several generic steps were addressed (e.g. plant transformation and screening, seed bank generation, genetic stability, host plant uniformity) as well as product-specific aspects (e.g. product quantity). This report summarizes the efforts undertaken to analyse and define the procedures for the GMP/GACP-compliant upstream production of 2G12 in transgenic tobacco plants from gene to harvest, including the design of expression constructs, plant transformation, the generation of production lines, master and working seed banks and the detailed investigation of cultivation and harvesting parameters and their impact on biomass, product yield and intra/interbatch variability. The resulting procedures were successfully translated into a prototypic manufacturing process that has been approved by the German competent authority.

A highly stable minimally processed plant-derived recombinant acetylcholinesterase for nerve agent detection in adverse conditions

Although recent innovations in transient plant systems have enabled gram quantities of proteins in 1-2 weeks, very few have been translated into applications due to technical challenges and high downstream processing costs. Here we report high-level production, using a Nicotiana benthamiana/p19 system, of an engineered recombinant human acetylcholinesterase (rAChE) that is highly stable in a minimally processed leaf extract. Lyophylized clarified extracts withstand prolonged storage at 70 °C and, upon reconstitution, can be used in several devices to detect organophosphate (OP) nerve agents and pesticides on surfaces ranging from 0 °C to 50 °C. The recent use of sarin in Syria highlights the urgent need for nerve agent detection and countermeasures necessary for preparedness and emergency responses. Bypassing cumbersome and expensive downstream processes has enabled us to fully exploit the speed, low cost and scalability of transient production systems resulting in the first successful implementation of plant-produced rAChE into a commercial biotechnology product.

Heat-precipitation allows the efficient purification of a functional plant-derived malaria transmission-blocking vaccine candidate fusion protein

Malaria is a vector-borne disease affecting more than two million people and accounting for more than 600,000 deaths each year, especially in developing countries. The most serious form of malaria is caused by Plasmodium falciparum. The complex life cycle of this parasite, involving pre-erythrocytic, asexual and sexual stages, makes vaccine development cumbersome but also offers a broad spectrum of vaccine candidates targeting exactly those stages. Vaccines targeting the sexual stage of P. falciparum are called transmission-blocking vaccines (TBVs). They do not confer protection for the vaccinated individual but aim to reduce or prevent the transmission of the parasite within a population and are therefore regarded as an essential tool in the fight against the disease. Malaria predominantly affects large populations in developing countries, so TBVs need to be produced in large quantities at low cost. Combining the advantages of eukaryotic expression with a virtually unlimited upscaling potential and a good product safety profile, plant-based expression systems represent a suitable alternative for the production of TBVs. We report here the high level (300 μg/g fresh leaf weight (FLW)) transient expression in Nicotiana benthamiana leaves of an effective TBV candidate based on a fusion protein F0 comprising Pfs25 and the C0-domain of Pfs230, and the implementation of a simple and cost-effective heat treatment step for purification that yields intact recombinant protein at >90% purity with a recovery rate of >70%. The immunization of mice clearly showed that antibodies raised against plant-derived F0 completely blocked the formation of oocysts in a malaria transmission-blocking assay (TBA) making F0 an interesting TBV candidate or a component of a multi-stage malaria vaccine cocktail.

Effects of a high-caloric diet and physical exercise on brain metabolite levels: a combined proton MRS and histologic study

Excessive intake of high-caloric diets as well as subsequent development of obesity and diabetes mellitus may exert a wide range of unfavorable effects on the central nervous system (CNS). It has been suggested that one mechanism in this context is the promotion of neuroinflammation. The potentially harmful effects of such diets were suggested to be mitigated by physical exercise. Here, we conducted a study investigating the effects of physical exercise in a cafeteria-diet mouse model on CNS metabolites by means of in vivo proton magnetic resonance spectroscopy ((1)HMRS). In addition postmortem histologic and real-time (RT)-PCR analyses for inflammatory markers were performed. Cafeteria diet induced obesity and hyperglycemia, which was only partially moderated by exercise. It also induced several changes in CNS metabolites such as reduced hippocampal glutamate (Glu), choline-containing compounds (tCho) and N-acetylaspartate (NAA)+N-acetyl-aspartyl-glutamic acid (NAAG) (tNAA) levels, whereas opposite effects were seen for running. No association of these effects with markers of central inflammation could be observed. These findings suggest that while voluntary wheel running alone is insufficient to prevent the unfavorable peripheral sequelae of the diet, it counteracted many changes in brain metabolites. The observed effects seem to be independent of neuroinflammation.

Pharmacokinetics and immunogenicity of broadly neutralizing HIV monoclonal antibodies in macaques

The identification of highly potent broadly neutralizing antibodies (bnAbs) against HIV-1, and success in preventing SHIV infection following their passive administration, have increased the likelihood that immunotherapeutic strategies can be adopted to prevent and treat HIV-1 infection. However, while broad and potent neutralizing activity is an essential prerequisite, in vivo properties such as good circulatory stability and non-immunogenicity are equally critical for developing a human treatment. In the present study, glycoforms of the bnAbs 10-1074, NIH45-46G54W, 10E8, PGT121, PGT128, PGT145, PGT135, PG9, PG16, VRC01 and b12 were produced by Agrobacterium-mediated transient transfection of Nicotiana benthamiana and assessed following administration in rhesus macaques. The results indicate that (i) N-glycans within the VL domain impair plasma stability of plant-derived bnAbs and (ii) while PGT121 and b12 exhibit no immunogenicity in rhesus macaques after multiple injections, VRC01, 10-1074 and NIH45-46G54W elicit high titer anti-idiotypic antibodies following a second injection. These anti-idiotypic antibodies specifically bind the administered bnAb or a close family member, and inhibit the bnAb in neutralization assays. These findings suggest that specific mutations in certain bnAbs contribute to their immunogenicity and call attention to the prospect that these mutated bnAbs will be immunogenic in humans, potentially compromising their value for prophylaxis and therapy of HIV-1.

The increasing value of plant-made proteins

The production of high-value proteins in plants is maturing, as shown by the recent approval of innovative products and the latest studies that showcase plant-based production systems using technologies and approaches that are well established in other fields. These include host cell engineering, medium optimization, scalable unit operations for downstream processing (DSP), bioprocess optimization and detailed cost analysis. Product-specific benefits of plant-based systems have also been exploited, including bioencapsulation and the mucosal delivery of minimally processed topical and oral products with a lower entry barrier than pharmaceuticals for injection. Success stories spearheaded by the FDA approval of Elelyso developed by Protalix have revitalized the field and further interest has been fueled by the production of experimental Ebola treatments in plants.

Application of a Scalable Plant Transient Gene Expression Platform for Malaria Vaccine Development

Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route toward the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification, and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs, and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here, we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility, and stability using fluorescent fusion proteins. Our results have been implemented for the evidence-based iterative design and expression of vaccine candidates combining suitable P. falciparum antigen domains. The antigens were also produced, purified, and characterized in further studies by taking advantage of the scalability of this platform.

Alternative intronic polyadenylation generates the interleukin-6 trans-signaling inhibitor sgp130-E10

Interleukin (IL)-6 signals via a receptor complex composed of the signal-transducing β-receptor gp130 and the non-signaling membrane-bound or soluble IL-6 receptor α (IL-6R, sIL-6R), which is referred to as classic and trans-signaling, respectively. IL-6 trans-signaling is functionally associated with the development of chronic inflammatory diseases and cancer. Soluble gp130 (sgp130) variants are natural inhibitors of trans-signaling. Differential splicing yields sgp130 isoforms. Here, we describe that alternative intronic polyadenylation in intron 10 of the gp130 transcript results in a novel mRNA coding for an sgp130 protein isoform (sgp130-E10) of 70-80 kDa. The sgp130-E10 protein was expressed in vivo in human peripheral blood mononuclear cells. To assess the biological activity of sgp130-E10, we expressed this variant as Fc-tagged fusion protein (sgp130-E10Fc). Recombinant sgp130-E10Fc binds to a complex of IL-6 and sIL-6R, but not to IL-6 alone, and specifically inhibits IL-6 trans-signaling. Thus, it might play an important role in the regulation of trans-signaling in vivo.

Signal-to-noise ratio of a mouse brain (13) C CryoProbe™ system in comparison with room temperature coils: spectroscopic phantom and in vivo results

MRI and MRS in small rodents demand very high sensitivity. Cryogenic transmit/receive radiofrequency probes (CryoProbes) designed for (1) H MRI of mouse brain provide an attractive option for increasing the performance of small-animal MR systems. As the Larmor frequency of (13) C nuclei is four times lower than that for (1) H nuclei, an even larger sensitivity improvement is expected for (13) C applications. The aim of this work was to evaluate the performance of a prototype (13) C CryoProbe™ for mouse brain MRS. To investigate the possible gain of the (13) C CryoProbe™, we acquired localized single-voxel (13) C spectra and chemical shift images of a dimethyl sulfoxide phantom with the CryoProbe™, as well as with two room temperature resonators. The cryogenically cooled resonator achieved approximately four-fold higher signal-to-noise ratio in phantom tests when compared with the best-performing room temperature coil. In addition, we present localized (13) C spectra of mouse brain obtained with the CryoProbe™, as well as with one of the room temperature coils, demonstrating the performance in vivo. In summary, the cryogenic cooling technique significantly enhances the (13) C signal sensitivity at 9.4 T and enables the investigation of metabolism within mouse brain.