The COVID-19 pandemic has shown the critical importance of vaccination strategies to protect vulnerable populations, including pregnant women, from severe disease and its lingering consequences. Although growing evidence demonstrates that COVID-19 vaccines are both safe and highly beneficial during pregnancy, vaccine hesitancy among pregnant women persists, partly fueled by the persistent, decade-old "urban myth" linking vaccination during pregnancy to neuropsychiatric disorders in children. Here we used a mouse model of passive immunization with severe acute respiratory syndrome coronavirus 2 spike neutralizing monoclonal antibodies (SaCoV-AB) to determine the effects of gestational COVID-19 vaccination on key pregnancy outcomes, maternal and offspring health, and behavior. We show that at a higher SaCoV-AB dosage, maternal immune response is reflected in elevated TNF-α levels in maternal serum, but not in the placenta or the fetal brain, with no effect on pregnancy outcomes. We report no consequences for postpartum maternal care behavior and neonatal communication signatures. Behavioral assessment of adult female and male offspring after maternal SaCoV-AB treatment revealed no differences in phenotypes relevant to neurodevelopmental disorders. Our findings indicate that in a preclinical model, passive immunization with SaCoV-AB during pregnancy is well-tolerated, with no discernable impact on maternal or offspring health and behavior.

Obesity and allergies are among the most common diseases of our civilization. Given the simultaneous rise in the prevalence of these diseases in recent years, a potential causal link between the two has been proposed. In particular, obese patients are at an increased risk of developing bronchial asthma, likely due to mechanical restrictions but also to metabolic changes that adversely affect immune function. Neuroscience studies have also shown that obesity can lead to impaired brain function and mental health. In the following review, we will take a closer look at our studies that focus on the influence of obesity on allergic diseases and cognitive performance. Both human studies and animal models (mice) have shown that obesity leads to increased allergic responses in the airways. Our studies in a mouse model of obesity confirm that an obese phenotype is associated with increased allergic sensitization and manifestation. These changes are associated with significant shifts in the composition of the gut microbial flora. The microbiome changes are further associated with allergic airway inflammation and an increased incidence of T helper 1 (Th1) type pulmonary macrophages. Interestingly, despite the changes in the microbiome, it is possible to effectively prevent allergy development by inducing oral tolerance. Furthermore, it was observed that obese mice show increased signs of anxiety and depression, as well as reduced cognitive performance. Obesity is a complex metabolic disease that significantly impacts our body’s gut microbiome and immune system, resulting in an increased incidence of allergic asthma and neurological/psychological changes. Attention should be given to both the prophylactic and therapeutic measures to mitigate the impact of obesity, including oral tolerance for managing existing allergic diseases.

Empirical evidence suggests that heat exposure reduces food intake. However, the neurocircuit architecture and the signalling mechanisms that form an associative interface between sensory and metabolic modalities remain unknown, despite primary thermoceptive neurons in the pontine parabrachial nucleus becoming well characterized1. Tanycytes are a specialized cell type along the wall of the third ventricle2 that bidirectionally transport hormones and signalling molecules between the brain's parenchyma and ventricular system3-8. Here we show that tanycytes are activated upon acute thermal challenge and are necessary to reduce food intake afterwards. Virus-mediated gene manipulation and circuit mapping showed that thermosensing glutamatergic neurons of the parabrachial nucleus innervate tanycytes either directly or through second-order hypothalamic neurons. Heat-dependent Fos expression in tanycytes suggested their ability to produce signalling molecules, including vascular endothelial growth factor A (VEGFA). Instead of discharging VEGFA into the cerebrospinal fluid for a systemic effect, VEGFA was released along the parenchymal processes of tanycytes in the arcuate nucleus. VEGFA then increased the spike threshold of Flt1-expressing dopamine and agouti-related peptide (Agrp)-containing neurons, thus priming net anorexigenic output. Indeed, both acute heat and the chemogenetic activation of glutamatergic parabrachial neurons at thermoneutrality reduced food intake for hours, in a manner that is sensitive to both Vegfa loss-of-function and blockage of vesicle-associated membrane protein 2 (VAMP2)-dependent exocytosis from tanycytes. Overall, we define a multimodal neurocircuit in which tanycytes link parabrachial sensory relay to the long-term enforcement of a metabolic code.

The Poly (I:C) (polyriboinosinic-polyribocytidilic acid) paradigm of maternal immune activation (MIA) is most widely used as experimental model for the evaluation of the effects of gestational infection on the brain and behavior of the progeny. We have previously reported significant batch-to-batch variability in the effects of Poly (I:C), purchased from the same supplier (Sigma–Aldrich), on maternal and fetal immune responses and found these differences to be dependent on the relative amount of synthetic double-stranded RNA fragments in the high versus low molecular weight (LMW) range contained in the compound. We here resorted to Poly (I:C) purified for LMW dsRNA fragments to establish a MIA paradigm with increased reproducibility and enhanced standardization in an effort to refine the MIA paradigm and characterize its effect on offspring behavior. We found that the parallel application of LMW Poly (I:C) in two different MIA-experienced laboratories (Vienna and Zurich) yielded differential outcomes in terms of maternal immune responses and behavioral phenotypes in the offspring generation. In both experimental sites, administration of LMW Poly (I:C) induced a significant sickness response and cytokine induction in the pregnant dam and fetal brains, while the expected deficit in sociability as one main behavioral outcome parameter in the MIA progeny, was only present in the Zurich, but not the Vienna cohort. We conclude that although using Poly (I:C) purified for a defined molecular weight range reduces batch-to-batch variability, it does not make the MIA model more reliable and robust. The differential response in behavioral phenotypes of the MIA offspring between the two laboratories illustrates the highly complex interaction between prenatal and postnatal milieus - including the laboratory environment - that determine offspring phenotypic outcomes after MIA. Consequently, establishing a new MIA protocol or implementing the MIA model firstly under new or changed environmental conditions must include the assessment of offspring behavior to ensure solid and reproducible experimental outcomes.

Hintergrund: Adipositas und Allergien gehören zu den häufigsten Zivilisationserkrankungen, die erhebliche Belastungen für die Betroffenen wie auch die Gesundheitssysteme mit sich bringen. Aufgrund des parallelen Anstiegs dieser Erkrankungen in den letzten Jahren wird ein kausaler Zusammenhang zwischen diesen beiden Zivilisationserkrankungen vermutet. Insbesondere zeigt sich, dass adipöse Patienten ein erhöhtes Risiko haben, an Asthma bronchiale zu erkranken, möglicherweise aufgrund mechanischer Einschränkungen, aber auch durch metabolische Veränderungen, die einen negativen Einfluss auf die Immunfunktion haben. Neurowissenschaftliche Studien haben zudem gezeigt, dass Adipositas zur Beeinträchtigung von Gehirnleistung und psychischer Gesundheit führen kann. Im Folgenden werden daher unsere Untersuchungen näher beleuchtet, die sich auf den Einfluss von Adipositas auf allergische Erkrankungen und kognitive Leistungen konzentrieren. Ergebnisse: Sowohl in humanen Studien als auch im Tiermodell (Maus) wurde gezeigt, dass Übergewicht zu verstärkten allergischen Reaktionen im Respirationstrakt führt. Unsere Studien in einem Mausmodell für Adipositas bestätigen, dass ein adipöser Phänotyp mit verstärkter allergischer Sensibilisierung und Manifestation assoziiert ist. Diese Veränderungen gehen mit deutlichen Verschiebungen in der Zusammensetzung der mikrobiellen Darmflora einher. Diese Mikrobiomveränderungen sind im Weiteren mit allergischen Atemwegsentzündungen und vermehrtem Auftreten von pulmonalen Makrophagen vom Typ-1-T-Helferzellen (Th1) verbunden. Interessanterweise ist es trotz der Mikrobiomveränderungen möglich, die Allergieentwicklung durch Induktion von oraler Toleranz effektiv zu verhindern. Darüber hinaus wurde beobachtet, dass adipöse Mäuse, besonders im Zuge einer allergischen Sensibilisierung, vermehrt Anzeichen von Angst und Depression sowie eine verminderte kognitive Leistungsfähigkeit aufweisen. Fazit: Adipositas ist eine komplexe metabolische Erkrankung, die einen erheblichen Einfluss auf das Darmmikrobiom und das Immunsystem unseres Körpers ausübt, und in Folge vermehrtes Auftreten von allergischem Asthma, aber auch neurologisch/psychische Veränderungen bedingt. Augenmerk muss daher daraufgelegt werden, welche prophylaktischen und therapeutischen Maßnahmen zu treffen sind, um die Folgeerscheinungen von Adipositas zu reduzieren. Eine der Maßnahmen ist die orale Toleranzinduktion bei (bestehenden) allergischen Erkrankungen. Zitierweise: Geissler N, Garner-Spitzer E, Inic-Kanada A, Pollak DD, Wiedermann U. The Impact of Obesity on Allergic Respiratory Diseases and on Mental and Cognitive Performance. Allergo J Int 2024;33:247-51

Psychostimulants interacting with the dopamine transporter (DAT) can be used illicitly or for the treatment of specific neuropsychiatric disorders. However, they can also produce severe and persistent adverse events. Often, their pharmacological properties in vitro do not fully correlate to their pharmacological profile in vivo. Here, we investigated the pharmacological effects of enantiomers of pyrovalerone, α-pyrrolidinovalerophenone, and 3,4-methylenedioxypyrovalerone as compared to the traditional psychostimulants cocaine and methylphenidate, using a variety of in vitro, computational, and in vivo approaches. We found that in vitro drug-binding kinetics at DAT correlate with the time-course of in vivo psychostimulant action in mice. In particular, a slow dissociation (i.e., slowkoff) ofS-enantiomers of pyrovalerone analogs from DAT predicts their more persistent in vivo effects when compared to cocaine and methylphenidate. Overall, our findings highlight the critical importance of drug-binding kinetics at DAT for determining the in vivo profile of effects produced by psychostimulant drugs.

Obesity is a key medical challenge of our time. The increasing number of children born to overweight or obese women is alarming. During pregnancy, the circulation of the mother and her fetus interact to maintain the uninterrupted availability of essential nutrients for fetal organ development. In doing so, the mother's dietary preference determines the amount and composition of nutrients reaching the fetus. In particular, the availability of polyunsaturated fatty acids (PUFAs), chiefly their ω‐3 and ω‐6 subclasses, can change when pregnant women choose a specific diet. Here, we provide a succinct overview of PUFA biochemistry, including exchange routes between ω‐3 and ω‐6 PUFAs, the phenotypes, and probable neurodevelopmental disease associations of offspring born to mothers consuming specific PUFAs, and their mechanistic study in experimental models to typify signaling pathways, transcriptional, and epigenetic mechanisms by which PUFAs can imprint long‐lasting modifications to brain structure and function. We emphasize that the ratio, rather than the amount of individual ω‐3 or ω‐6 PUFAs, might underpin physiologically correct cellular differentiation programs, be these for neurons or glia, during pregnancy. Thereupon, the PUFA‐driven programming of the brain is contextualized for childhood obesity, metabolic, and endocrine illnesses.

Background/Objective Iron deficiency (ID) is the most common nutrient deficiency, affecting two billion people worldwide, including about 30% of pregnant women. During gestation, the brain is particularly vulnerable to environmental insults, which can irrevocably impair critical developmental processes. Consequently, detrimental consequences of early-life ID for offspring brain structure and function have been described. Although early life ID has been associated with an increased long-term risk for several neuropsychiatric disorders, the effect on depressive disorders has remained unresolved.Materials and methods A mouse model of moderate foetal and neonatal ID was established by keeping pregnant dams on an iron-deficient diet throughout gestation until postnatal day 10. The ensuing significant decrease of iron content in the offspring brain, as well as the impact on maternal behaviour and offspring vocalization was determined in the first postnatal week. The consequences of early-life ID for depression- and anxiety-like behaviour in adulthood were revealed employing dedicated behavioural assays. miRNA sequencing of hippocampal tissue of offspring revealed specific miRNAs signatures accompanying the behavioural deficits of foetal and neonatal ID in the adult brain.Results Mothers receiving iron-deficient food during pregnancy and lactation exhibited significantly less licking and grooming behaviour, while active pup retrieval and pup ultrasonic vocalizations were unaltered. Adult offspring with a history of foetal and neonatal ID showed an increase in depression- and anxiety-like behaviour, paralleled by a deranged miRNA expression profile in the hippocampus, specifically levels of miR200a and miR200b.Conclusion ID during the foetal and neonatal periods has life-long consequences for affective behaviour in mice and leaves a specific and persistent mark on the expression of miRNAs in the brain. Foetal and neonatal ID needs to be further considered as risk factor for the development of depression and anxiety disorders later in life.Key MessagesMarginal reduction of gestational alimentary iron intake decreases brain iron content of the juvenile offspring.Early-life ID is associated with increased depression- and anxiety-like behaviour in adulthood.Reduction of maternal alimentary iron intake during pregnancy is reflected in an alteration of miRNA signatures in the adult offspring brain.

Adverse influences during pregnancy are associated with a range of unfavorable outcomes for the developing offspring. Maternal psychosocial stress, exposure to infections and nutritional imbalances are known risk factors for neurodevelopmental derangements and according psychiatric and neurological manifestations later in offspring life. In this context, the maternal immune activation (MIA) model has been extensively used in preclinical research to study how stimulation of the maternal immune system during gestation derails the tightly coordinated sequence of fetal neurodevelopment. The ensuing consequence of MIA for offspring brain structure and function are majorly manifested in behavioral and cognitive abnormalities, phenotypically presenting during the periods of adolescence and adulthood. These observations have been interpreted within the framework of the "double-hit-hypothesis" suggesting that an elevated risk for neurodevelopmental disorders results from an individual being subjected to two adverse environmental influences at distinct periods of life, jointly leading to the emergence of pathology. The early postnatal period, during which the caregiving parent is the major determinant of the newborn´s environment, constitutes a window of vulnerability to external stimuli. Considering that MIA not only affects the developing fetus, but also impinges on the mother´s brain, which is in a state of heightened malleability during pregnancy, the impact of MIA on maternal brain function and behavior postpartum may importantly contribute to the detrimental consequences for her progeny. Here we review current information on the interaction between the prenatal and postnatal maternal environments in the modulation of offspring development and their relevance for the pathophysiology of the MIA model.

The ability to care for the young is innate and readily displayed by postpartum females after delivery to ensure offspring survival. Upon pup exposure, rodent virgin (nulliparous) females also develop parental behavior that over time becomes displayed at levels equivalent to parenting mothers. Although maternal behavior in postpartum females and the associated neurocircuits are well characterized, the neural mechanisms underlying the acquisition of maternal behavior without prior experience remain poorly understood. Here, we show that the development of maternal care behavior in response to first-time pup exposure in virgin females is initiated by the activation of the anterior cingulate cortex (ACC). ACC activity is dependent on feedback excitation by Vglut2+ /Galanin+ neurons of the centrolateral nucleus of the thalamus (CL), with their activity sufficient to display parenting behaviors. Accordingly, acute bidirectional chemogenetic manipulation of neuronal activity in the ACC facilitates or impairs the attainment of maternal behavior, exclusively in virgin females. These results reveal an ACC-CL neurocircuit as an accessory loop in virgin females for the initiation of maternal care upon first-time exposure to pups.

Hygiene management protocols in laboratory mouse husbandries worldwide most commonly employ soiled bedding-exposed sentinel mice to monitor the occurrence of infections in mouse colonies. Using this approach, sentinel mice repeatedly receive a mixture of used bedding, supplied by a variety of cages of a defined hygienic unit for a period of several months. Hereby, microorganisms shed in the used bedding can infect the sentinel animals and can be detected in subsequent health monitoring procedures. However, murine excrements carry more than only microorganisms. Mouse feces and urine also contain a multitude of olfactory molecules, which the animals use to code information about social status and context. However, if and how the persistent and repeated experience with these odor cues affects the behavior of sentinel mice, has not yet been explored. To address this question, we conducted a longitudinal study for neurochemical output parameters related to an organism's responsiveness to challenging conditions, and for the exploratory assessment of a panel of home cage behaviors in soiled bedding and control female C57BL/6J mice. We found that the number of mice showing abnormal repetitive behaviors, including barbering and bar mouthing, was lower in the soiled bedding group. While neutrophil/lymphocyte ratios and fecal corticosterone metabolites did not differ between groups, the within-group variance of the neutrophil/lymphocyte ratio was reduced in the soiled bedding group. These results show that the occurrence of abnormal repetitive behaviors is lower in sentinel than in control mice and suggest a beneficial effect of soiled bedding on the welfare of laboratory mice and on outcome variability.

Epidemiological studies indicate a bidirectional association between metabolic disturbances, including obesity and related pathological states, and mood disorders, most prominently major depression. However, the biological mechanisms mediating the comorbid relationship between the deranged metabolic and mood states remain incompletely understood. Here, we tested the hypothesis that the enhanced activation of brown fat tissue (BAT), known to beneficially regulate obesity and accompanying dysfunctional metabolic states, is also paralleled by an alteration of affective behaviour. We used upstream stimulatory factor 1 (USF-1) knock-out (KO) mice as a genetic model of constitutively activated BAT and positive cardiometabolic traits and found a reduction of depression-like and anxiety-like behaviours associated with USF-1 deficiency. Surgical removal of interscapular BAT did not impact the behavioural phenotype of USF-1 KO mice. Further, the absence of USF-1 did not lead to alterations of adult hippocampal neural progenitor cell proliferation, differentiation, or survival. RNA-seq analysis characterised the molecular signature of USF-1 deficiency in the hippocampus and revealed a significant increase in the expression of several members of the X-linked lymphocyte-regulated (xlr) genes, including xlr3b and xlr4b. Xlr genes are the mouse orthologues of the human FAM9 gene family and are implicated in the regulation of dendritic branching, dendritic spine number and morphology. The transcriptional changes were associated with morphological alterations in hippocampal neurons, manifested in reduced dendritic length and complexity in USF-1 KO mice. Collectively these data suggest that the metabolic regulator USF-1 is involved in the control of affective behaviour in mice and that this modulation of mood states is unrelated to USF-1-dependent BAT activation, but reflected in structural changes in the brain.

Increasing extracellular levels of serotonin (5-HT) in the brain ameliorates symptoms of depression and anxiety-related disorders, e.g., social phobias and post-traumatic stress disorder. Recent evidence from preclinical and clinical studies established the therapeutic potential of drugs inducing the release of 5-HT via the 5-HT-transporter. Nevertheless, current 5-HT releasing compounds under clinical investigation carry the risk for abuse and deleterious side effects. Here, we demonstrate that S-enantiomers of certain ring-substituted cathinones show preference for the release of 5-HT ex vivo and in vivo, and exert 5-HT-associated effects in preclinical behavioral models. Importantly, the lead cathinone compounds (1) do not induce substantial dopamine release and (2) display reduced off-target activity at vesicular monoamine transporters and 5-HT2B-receptors, indicative of low abuse-liability and low potential for adverse events. Taken together, our findings identify these agents as lead compounds that may prove useful for the treatment of disorders where elevation of 5-HT has proven beneficial.

Experimental investigation of early postnatal brain development in infant mice (<postnatal day 10) is challenging because of the rapid expansion of their brain volume and the fragility of cranial bones. Stereotaxic adaptors that are commercially available usually evoke significant compression forces, thus limiting the accuracy of micromanipulations. Here, we took advantage of recent progress in 3D printing for the cost-effective production of stereotaxic adaptors for infant mice. Our designs offer gentle head positioning, tailored incisor placement and high precision, while also integrating evaporator and tubing components for gaseous anaesthesia. Thus, post-procedural lethality is minimized even upon time-consuming surgeries. Viral microinjections through glass capillaries are shown as proof of principle to experimentally validate targeting accuracy in mice aged 6–10 days. The exact engineering workflow and printing protocol are disseminated for open-label use. Overall, we present technical details and experimental data on a stereotaxic device that can help neurobiologists working at a particularly complex developmental stage in mice.

Immune activation is one of the most common complications during pregnancy, predominantly evoked by viral infections. Nevertheless, how immune activation affects mother-offspring relationships postpartum remains unknown. Here, by using the polyinosinic-polycytidylic acid (Poly I:C) model of gestational infection we show that viral-like immune activation at mid-gestation persistently changes hypothalamic neurocircuit parameters in mouse dams and, consequently, is adverse to parenting behavior. Poly I:C-exposed dams favor non-pup-directed exploratory behavior at the expense of pup retrieval. These behavioral deficits are underlain by dendrite pruning and lesser immediate early gene activation in Galanin (Gal)+ neurons with dam-specific transcriptional signatures that reside in the medial preoptic area (mPOA). Reduced activation of an exclusively inhibitory contingent of these distal-projecting Gal+ neurons allows for increased feed-forward inhibition onto putative dopaminergic neurons in the ventral tegmental area (VTA) in Poly I:C-exposed dams. Notably, destabilized VTA output specifically accompanies post-pup retrieval epochs. We suggest that gestational immunogenic insults bias both threat processing and reward perception, manifesting as disfavored infant caregiving.

Experimental investigation of early postnatal brain development in infant mice (

First-generation vaccines against SARS-CoV-2 do not provide adequate immune protection. Therefore, we engineered a divalent gene construct combining the receptor-binding domain (RBD) of the spike protein and the immunodominant region of the viral nucleocapsid. This fusion protein was produced in either E. coli or a recombinant baculovirus system. Subsequently, the fusion protein was mixed with adjuvant and administered to mice in a prime-booster mode. Mice (72%) produced an IgG response against both proteins (titer: 10(-4)-10(-5)) 14 days after the first booster injection, which was increased to 100% by a second booster. Comparable IgG responses were detected against the delta, gamma and omicron variants of the RBD region. Durability testing revealed IgGs beyond 90 days. In addition, cytolytic effector cell molecules were increased in lymphocytes isolated from peripheral blood. Ex vivo stimulation of T cells by nucleocapsid and RBD peptides showed antigen-specific upregulation of CD44 among the CD4(+) and CD8(+) T cells of vaccinated mice. No side effect was documented in the central nervous system. Cumulatively, these data represent a proof-of-principle approach alternative to existing mRNA vaccination strategies.

First-generation vaccines against SARS-CoV-2 have been administered to more than 60% of the population in developed countries. However, the monovalent vaccines currently available in Europe do not confer adequate and durable immune protection. To satisfy the need for a novel vaccine, we engineered a divalent gene construct consisting of the receptor binding domain (RBD, 300-685 aa) of the spike protein and the immunodominant region of the nucleocapsid (100-300 aa). This fusion protein was cloned into a pET-30a plasmid and expressed either in Escherichia coli or in a recombinant baculovirus in insect cells. Following purification via its His-tag, the fusion protein was mixed with adjuvant, and administered to mice in a prime-booster-mode. Upon testing for IgG antibody response against nucleocapsid and RBD, a titer of 10−4 - 10−5 was demonstrated 14 days after the first booster injection in 72% of the animals, which could be increased to 100% by a second booster. Notably, comparable IgG responses were detected against the delta, gamma and omicron variants of the RBD region. Durability testing revealed the presence of IgG beyond 90 days. In addition, granzyme A and perforin mRNA expression (cytolytic effector cell molecules) was increased in cytotoxic lymphocytes isolated from peripheral blood. Ex vivo stimulation of T-cells by nucleocapsid and RBD peptides showed antigen-specific upregulation of CD44 in vaccinated mice among their CD4+ and CD8+ T-cells. No side-effect was documented in the central nervous system, be it either endothelial inflammation or neuronal damage. Cumulatively, the combined induction of B-cell and T-cell response by a bivalent protein-based vaccine directed against two structural SARS-CoV-2 proteins represents a proof-of-principle approach alternative to existing mRNA vaccination strategies, which could confer long-lasting immunity against all known viral strains.