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Early life pain and stress have lasting consequences on nervous system development that can interact with later stress or trauma to create a susceptibility to fear, anxiety, depression and chronic pain among other psychological disorders. Recent work has identified changes in corticotropin releasing factor signaling in limbic system structures, such as the amygdala and hypothalamus, as a key mechanism behind these changes – albeit in a sex-dependent manner. CRF has two major receptors, CRFR1 and CRFR2 which have also been shown to play key roles in fear and pain expression. The current work examines the effects of early life pain designed to mimic the neonatal medical trauma that occurs in the Neonatal Intensive Care Unit (NICU), paired with a juvenile trauma in the form of fear conditioning, on expression of crhr1 and crhr2 mRNA in the central nucleus (CeA) and basolateral nucleus (BLA) of the amygdala as well as the paraventricular nucleus (PVN) and ventromedial nucleus (VMH) hypothalamus of the juvenile rat. While prior work has demonstrated that early life pain significantly impacts expression of the CRF ligand mRNA, this study examines the effects of early life pain and stress, as well as adolescent fear conditioning, on CRF receptor expression. The data demonstrate that early life pain and fear conditioning have only modest effects on CRF receptor expression in the amygdala and hypothalamus in a sex dependent manner. In both sexes, fear conditioning increased crhr2 mRNA in the CeA only in neonatally undisturbed subjects. In addition, there was a trend towards altered crhr2 mRNA following neonatal manipulation in the PVN. In females specifically, we observed significant changes in crhr2 mRNA expression following fear conditioning in the right BLA. There were no female-specific changes following neonatal pain and stress. In males, we observed significant changes in crhr1 mRNA in the posterior PVN and trends toward changes in crhr2 mRNA in the CeA and VMH following neonatal manipulation. Together, these data confirm prior work that early life pain and stress alter the neural circuitry of pain and stress in a sex-specific manner. However, given the limited changes observed, in it unlikely that CRH receptor alterations are a major mechanism of action of early life pain.

Neonatal intensive care units (NICUs) provide life-saving care for preterm and sick neonates, but many medical procedures are painful and stress-inducing. Even a routine NICU procedure, such as the \"heel lancing\" blood-draw procedure, is an acutely painful, repetitive manipulation that has lasting negative impacts on pain perception and anxiety responses. The intersection of nociception and negative affect occurs in a brain region called the central nucleus of the amygdala (CeA), and neurons expressing corticotropin-releasing factor (CRF) have been implicated in studies of both anxiety and pain. Using a two-hit model of trauma-induced pain vulnerability-where repetitive needle prickings occur during the first week of life (\"our NICU model\"), followed by a second stressor (e.g., fear conditioning) during adolescence-our lab has observed a mechanical hypersensitivity in rats that endured our NICU model that manifests only after fear conditioning. We have also observed changes to expression and activation of CeA-CRF neurons after the NICU-like experience with an acute increase followed by a lasting reduction in the number of CRF cells in the right CeA of adolescent male rats. However, the relationship between these changes and the observed behavioral outcomes remains unclear, as does the function of the remaining CRF cell population. We hypothesize that the remaining population of CRF-expressing CeA neurons are functionally altered by early life pain and stress and primed to respond more readily, such that vulnerability to stress-induced hypersensitivity is increased. Through chemogenetic inhibition of the amygdala, or specifically CeA-CRF neurons, we demonstrate that development of stress-induced mechanical hypersensitivity after our NICU model is completely reversed through silencing the amygdala. Inhibiting only CeA-CRF neurons during fear conditioning led to a partial reversal of the hypersensitivity, suggesting that other populations of cells also play critical roles. Nevertheless, we demonstrate that the NICU-like experience results in a lasting hyperexcitability of CeA-CRF neurons during adolescence, confirming that this population is affected by the early life manipulations. In all, this study suggests that CeA-CRF neurons may have pro-nociceptive properties that are exacerbated by early life pain and result in maladaptive responding to subsequent traumatic events.

Anxiety disorders often emerge during childhood. Rodent models using classical fear conditioning have shown that different types of fear depend upon different neural structures and may emerge at different stages of development. For example, some work has suggested that contextual fear conditioning generally emerges later in development (postnatal day 23-24) than explicitly cued fear conditioning (postnatal day 15-17) in rats. This has been attributed to an inability of younger subjects to form a representation of the context due to an immature hippocampus. However, evidence that contextual fear can be observed in postnatal day 17 subjects and that cued fear conditioning continues to emerge past this age raises questions about the nature of this deficit. The current studies examine this question using both the context pre-exposure facilitation effect for immediate single-shock contextual fear conditioning and traditional cued fear conditioning using Sprague-Dawley rats. The data suggest that both cued and contextual fear conditioning are continuing to develop between PD 17 and 24, consistent with development occurring the in essential fear conditioning circuit.

Early life pain and stress have lasting consequences on nervous system development that can interact with later stress or trauma to create a susceptibility to fear, anxiety, depression and chronic pain among other psychological disorders. Recent work has identified changes in corticotropin releasing factor signaling in limbic system structures, such as the amygdala and hypothalamus, as a key mechanism behind these changes - albeit in a sex-dependent manner. CRF has two major receptors, CRHR1 and CRHR2 which have also been shown to play key roles in fear and pain expression. The current work examines the effects of early life pain designed to mimic the neonatal medical trauma that occurs in the Neonatal Intensive Care Unit (NICU), paired with a juvenile trauma in the form of fear conditioning, on expression of and mRNA in the central (CeA) and basolateral (BLA) amygdala as well as the paraventricular (PVN) and ventromedial (VMH) hypothalamus. While prior work has demonstrated that early life pain significantly impacts expression of the CRF ligand, the current data demonstrate that early life pain and fear conditioning largely fail to affect CRH receptor expression in the amygdala. Modest changes in expression to in a sex and region-specific manner were observed in the hypothalamus.

A better understanding of animal emotion is an important goal in disciplines ranging from neuroscience to animal welfare science. The conscious experience of emotion cannot be assessed directly, but neural, behavioural and physiological indicators of emotion can be measured. Researchers have used these measures to characterize how animals respond to situations assumed to induce discrete emotional states (e.g. fear). While advancing our understanding of specific emotions, this discrete emotion approach lacks an overarching framework that can incorporate and integrate the wide range of possible emotional states. Dimensional approaches that conceptualize emotions in terms of universal core affective characteristics (e.g. valence (positivity versus negativity) and arousal) can provide such a framework. Here, we bring together discrete and dimensional approaches to: (i) offer a structure for integrating different discrete emotions that provides a functional perspective on the adaptive value of emotional states, (ii) suggest how long-term mood states arise from short-term discrete emotions, how they also influence these discrete emotions through a bi-directional relationship and how they may function to guide decision-making, and (iii) generate novel hypothesis-driven measures of animal emotion and mood.

Protein aggregates and damaged organelles are tagged with ubiquitin chains to trigger selective autophagy. To initiate mitophagy, the ubiquitin kinase PINK1 phosphorylates ubiquitin to activate the ubiquitin ligase parkin, which builds ubiquitin chains on mitochondrial outer membrane proteins, where they act to recruit autophagy receptors. Using genome editing to knockout five autophagy receptors in HeLa cells, here we show that two receptors previously linked to xenophagy, NDP52 and optineurin, are the primary receptors for PINK1- and parkin-mediated mitophagy. PINK1 recruits NDP52 and optineurin, but not p62, to mitochondria to activate mitophagy directly, independently of parkin. Once recruited to mitochondria, NDP52 and optineurin recruit the autophagy factors ULK1, DFCP1 and WIPI1 to focal spots proximal to mitochondria, revealing a function for these autophagy receptors upstream of LC3. This supports a new model in which PINK1-generated phospho-ubiquitin serves as the autophagy signal on mitochondria, and parkin then acts to amplify this signal. This work also suggests direct and broader roles for ubiquitin phosphorylation in other autophagy pathways. The PINK1 ubiquitin kinase is shown to recruit the two autophagy receptors NDP52 and OPTN to mitochondria to activate mitophagy directly, independently of the ubiquitin ligase parkin; once recruited to mitochondria, NDP52 and OPTN recruit autophagy initiation components, and parkin may amplify the phospho-ubiquitin signal generated by PINK1, resulting in robust autophagy induction. The role of parkin in mitophagy As in other forms of selective autophagy, during mitophagy the damaged cargo — the mitochondrion — is tagged with ubiquitin chains for recognition and subsequent degradation. Specifically, the enzyme PINK1 phosphorylates ubiquitin as part of the process to activate the ubiquitin ligase enzyme parkin. Consequently, parkin can build ubiquitin chains on mitochondrial outer membrane proteins to recruit autophagy receptors. Richard Youle and colleagues report an additional layer of regulatory complexity in this pathway, with a cellular role for phosphorylated ubiquitin. Using genome editing to knockout multiple autophagy receptors, the authors find that PINK1 recruits only two such receptors, NDP52 and optineurin, to mitochondria to directly activate mitophagy, independent of parkin. NDP52 and optineurin then recruit other autophagy components. These observations call for a revision of the current model of the role of parkin in mitophagy, suggesting that it amplifies the phospho-ubiquitin signal generated by PINK1 to signal autophagy.

The Rosetta software for macromolecular modeling, docking and design is extensively used in laboratories worldwide. During two decades of development by a community of laboratories at more than 60 institutions, Rosetta has been continuously refactored and extended. Its advantages are its performance and interoperability between broad modeling capabilities. Here we review tools developed in the last 5 years, including over 80 methods. We discuss improvements to the score function, user interfaces and usability. Rosetta is available at http://www.rosettacommons.org . This Perspective reviews tools developed over the past five years in the macromolecular modeling, docking and design software Rosetta.

Polymer materials of reduced size and dimensionality, such as thin films, polymer nanofibres and nanotubes, exhibit exceptional mechanical properties compared with those of their macroscopic counterparts. We discuss here the abrupt increase in Young's modulus in polymer nanofibres. Using scaling estimation we show that this effect occurs when, in the amorphous (non-crystalline) part of the nanofibres, the transversal size of regions consisting of orientation-correlated macromolecules is comparable to the nanofibre diameter, thereby resulting in confinement of the supramolecular structure. We suggest that in polymer nanofibres the resulting supramolecular microstructure plays a more dominant role in the deformation process than previously thought, challenging the commonly held view that surface effects are most significant. The concept we develop also provides a way to interpret the observed—but not yet understood—temperature dependence of Young's modulus in nanofibres of different diameters.

Failure of the host immune system to control infection with Mycobacterium tuberculosis is a major determinant of tuberculosis (TB) disease. In this work, we examined the role of macrophage migration inhibitory factor (MIF), a cytokine that is encoded in a functionally polymorphic locus in humans, in TB. We found genetic low expressers of MIF to be enriched in a population of patients with HIV and disseminated TB. From our work in cellular and mouse models, we propose a key mechanism by which MIF regulates bacterial recognition as the first step in triggering inflammatory pathways to enable mycobacterial control. Macrophage migration inhibitory factor (MIF), an innate cytokine encoded in a functionally polymorphic genetic locus, contributes to detrimental inflammation but may be crucial for controlling infection. We explored the role of variant MIF alleles in tuberculosis. In a Ugandan cohort, genetic low expressers of MIF were 2.4-times more frequently identified among patients with Mycobacterium tuberculosis (TB) bacteremia than those without. We also found mycobacteria-stimulated transcription of MIF and serum MIF levels to be correlated with MIF genotype in human macrophages and in a separate cohort of US TB patients, respectively. To determine mechanisms for MIF’s protective role, we studied both aerosolized and i.v. models of mycobacterial infection and observed MIF-deficient mice to succumb more quickly with higher organism burden, increased lung pathology, and decreased innate cytokine production (TNF-α, IL-12, IL-10). MIF-deficient animals showed increased pulmonary neutrophil accumulation but preserved adaptive immune response. MIF-deficient macrophages demonstrated decreased cytokine and reactive oxygen production and impaired mycobacterial killing. Transcriptional investigation of MIF-deficient macrophages revealed reduced expression of the pattern recognition receptor dectin-1; restoration of dectin-1 expression recovered innate cytokine production and mycobacterial killing. Our data place MIF in a crucial upstream position in the innate immune response to mycobacteria and suggest that commonly occurring low expression MIF alleles confer an increased risk of TB disease in some populations.