Silencing CA1 pyramidal cells output reveals the role of feedback inhibition in hippocampal oscillations.

The precise temporal coordination of neural activity is crucial for brain function. In the hippocampus, this precision is reflected in the oscillatory rhythms observed in CA1. While it is known that a balance between excitatory and inhibitory activity is necessary to generate and maintain these oscillations, the differential contribution of feedforward and feedback inhibition remains ambiguous. Here we use conditional genetics to chronically silence CA1 pyramidal cell transmission, ablating the ability of these neurons to recruit feedback inhibition in the local circuit, while recording physiological activity in mice. We find that this intervention leads to local pathophysiological events, with ripple amplitude and intrinsic frequency becoming significantly larger and spatially triggered local population spikes locked to the trough of the theta oscillation appearing during movement. These phenotypes demonstrate that feedback inhibition is crucial in maintaining local sparsity of activation and reveal the key role of lateral inhibition in CA1 in shaping circuit function.

Temporal evolution reveals bifurcated lineages in aggressive neuroendocrine small cell prostate cancer trans-differentiation.

Trans-differentiation from an adenocarcinoma to a small cell neuroendocrine state is associated with therapy resistance in multiple cancer types. To gain insight into the underlying molecular events of the trans-differentiation, we perform a multi-omics time course analysis of a pan-small cell neuroendocrine cancer model (termed PARCB), a forward genetic transformation using human prostate basal cells and identify a shared developmental, arc-like, and entropy-high trajectory among all transformation model replicates. Further mapping with single cell resolution reveals two distinct lineages defined by mutually exclusive expression of ASCL1 or ASCL2. Temporal regulation by groups of transcription factors across developmental stages reveals that cellular reprogramming precedes the induction of neuronal programs. TFAP4 and ASCL1/2 feedback are identified as potential regulators of ASCL1 and ASCL2 expression. Our study provides temporal transcriptional patterns and uncovers pan-tissue parallels between prostate and lung cancers, as well as connections to normal neuroendocrine cell states.

AA-forecast: anomaly-aware forecast for extreme events.

Time series models often are impacted by extreme events and anomalies, both prevalent in real-world datasets. Such models require careful probabilistic forecasts, which is vital in risk management for extreme events such as hurricanes and pandemics. However, it's challenging to automatically detect and learn from extreme events and anomalies for large-scale datasets which often results in extra manual efforts. Here, we propose an anomaly-aware forecast framework that leverages the effects of anomalies to improve its prediction accuracy during the presence of extreme events. Our model has trained to extract anomalies automatically and incorporates them through an attention mechanism to increase the accuracy of forecasts during extreme events. Moreover, the framework employs a dynamic uncertainty optimization algorithm that reduces the uncertainty of forecasts in an online manner. The proposed framework demonstrated consistent superior accuracy with less uncertainty on three datasets with different varieties of anomalies over the current prediction models.

Role of Calcr expressing neurons in the medial amygdala in social contact among females.

Social animals become stressed upon social isolation, proactively engaging in affiliative contacts among conspecifics after resocialization. We have previously reported that calcitonin receptor (Calcr) expressing neurons in the central part of the medial preoptic area (cMPOA) mediate contact-seeking behaviors in female mice. Calcr neurons in the posterodorsal part of the medial amygdala (MeApd) are also activated by resocialization, however their role in social affiliation is still unclear. Here we first investigated the functional characteristics of MeApd Calcr + cells; these neurons are GABAergic and show female-biased Calcr expression. Next, using an adeno-associated virus vector expressing a short hairpin RNA targeting Calcr we aimed to identify its molecular role in the MeApd. Inhibiting Calcr expression in the MeApd increased social contacts during resocialization without affecting locomotor activity, suggesting that the endogenous Calcr signaling in the MeApd suppresses social contacts. These results demonstrate the distinct roles of Calcr in the cMPOA and MeApd for regulating social affiliation.

Corrigendum to "Leveraging data analytics to understand the relationship between restaurants' safety violations and COVID-19 transmission" [Int. J. Hosp. Manag. 104 (2022) 103241].

[This corrects the article DOI: 10.1016/j.ijhm.2022.103241.].

Leveraging data analytics to understand the relationship between restaurants' safety violations and COVID-19 transmission.

This paper leverages natural language processing, spatial analysis, and statistical analysis to examine the relationship between restaurants' safety violations and COVID-19 cases. We used location-based consumers' complaints data during the early stage of business reopening in Florida, USA. First, statistical analysis was conducted to examine the correlation between restaurants' safety violations and COVID-19 transmission. Second, a neural network-based deep learning model was developed to perform topic modeling based on consumers' complaints. Third, spatial modeling of the complaints' geographic distributions was performed to identify the hotspots of consumers' complaints and COVID-19 cases. The results reveal a positive relationship between consumers' complaints about restaurants' safety violations and COVID-19 cases. In particular, consumers' complaints about personal protection measures had the highest correlation with COVID-19 cases, followed by environmental safety measures. Our analytical methods and findings shed light on customers' behavioral shifts and hospitality businesses' adaptive practices during a pandemic.

Amylin-Calcitonin receptor signaling in the medial preoptic area mediates affiliative social behaviors in female mice.

Social animals actively engage in contact with conspecifics and experience stress upon isolation. However, the neural mechanisms coordinating the sensing and seeking of social contacts are unclear. Here we report that amylin-calcitonin receptor (Calcr) signaling in the medial preoptic area (MPOA) mediates affiliative social contacts among adult female mice. Isolation of females from free social interactions first induces active contact-seeking, then depressive-like behavior, concurrent with a loss of Amylin mRNA expression in the MPOA. Reunion with peers induces physical contacts, activates both amylin- and Calcr-expressing neurons, and leads to a recovery of Amylin mRNA expression. Chemogenetic activation of amylin neurons increases and molecular knockdown of either amylin or Calcr attenuates contact-seeking behavior, respectively. Our data provide evidence in support of a previously postulated origin of social affiliation in mammals.

Plasticity of Extrachromosomal and Intrachromosomal BRAF Amplifications in Overcoming Targeted Therapy Dosage Challenges.

Focal amplifications (FA) can mediate targeted therapy resistance in cancer. Understanding the structure and dynamics of FAs is critical for designing treatments that overcome plasticity-mediated resistance. We developed a melanoma model of dual MAPK inhibitor (MAPKi) resistance that bears BRAFV600 amplifications through either extrachromosomal DNA (ecDNA)/double minutes (DM) or intrachromosomal homogenously staining regions (HSR). Cells harboring BRAFV600E FAs displayed mode switching between DMs and HSRs, from both de novo genetic changes and selection of preexisting subpopulations. Plasticity is not exclusive to ecDNAs, as cells harboring HSRs exhibit drug addiction-driven structural loss of BRAF amplicons upon dose reduction. FA mechanisms can couple with kinase domain duplications and alternative splicing to enhance resistance. Drug-responsive amplicon plasticity is observed in the clinic and can involve other MAPK pathway genes, such as RAF1 and NRAS. BRAF FA-mediated dual MAPKi-resistant cells are more sensitive to proferroptotic drugs, extending the spectrum of ferroptosis sensitivity in MAPKi resistance beyond cases of dedifferentiation. SIGNIFICANCE: Understanding the structure and dynamics of oncogene amplifications is critical for overcoming tumor relapse. BRAF amplifications are highly plastic under MAPKi dosage challenges in melanoma, through involvement of de novo genomic alterations, even in the HSR mode. Moreover, BRAF FA-driven, dual MAPKi-resistant cells extend the spectrum of resistance-linked ferroptosis sensitivity. This article is highlighted in the In This Issue feature, p. 873.

COVID-19 and the future of work in the hospitality industry.

The COVID-19 pandemic has significantly disrupted the hospitality industry. This research combines different data to examine the US labor market trends during COVID-19. It is found that low-preparation jobs in leisure and hospitality are the hardest hit and slow to recover. The pandemic has highlighted growing issues in workplace safety, skill gaps, technology adoption, and work reorganization in the hospitality industry. This paper develops two propositions about preparing hospitality workers for the future of work and providing flexible work arrangements.

CA2 inhibition reduces the precision of hippocampal assembly reactivation.

The structured reactivation of hippocampal neuronal ensembles during fast synchronous oscillatory events, termed sharp-wave ripples (SWRs), has been suggested to play a crucial role in the storage and use of memory. Activity in both the CA2 and CA3 subregions can precede this population activity in CA1, and chronic inhibition of either region alters SWR oscillations. However, the precise contribution of CA2 to the oscillation, as well as to the reactivation of CA1 neurons within it, remains unclear. Here, we employ chemogenetics to transiently silence CA2 pyramidal cells in mice, and we observe that although SWRs still occur, the reactivation of CA1 pyramidal cell ensembles within the events lose both temporal and informational precision. These observations suggest that CA2 activity contributes to the fidelity of experience-dependent hippocampal replay.

Calcitonin receptor signaling in the medial preoptic area enables risk-taking maternal care.

Maternal mammals exhibit heightened motivation to care for offspring, but the underlying neuromolecular mechanisms have yet to be clarified. Here, we report that the calcitonin receptor (Calcr) and its ligand amylin are expressed in distinct neuronal populations in the medial preoptic area (MPOA) and are upregulated in mothers. Calcr+ MPOA neurons activated by parental care project to somatomotor and monoaminergic brainstem nuclei. Retrograde monosynaptic tracing reveals that significant modification of afferents to Calcr+ neurons occurs in mothers. Knockdown of either Calcr or amylin gene expression hampers risk-taking maternal care, and specific silencing of Calcr+ MPOA neurons inhibits nurturing behaviors, while pharmacogenetic activation prevents infanticide in virgin males. These data indicate that Calcr+ MPOA neurons are required for both maternal and allomaternal nurturing behaviors and that upregulation of amylin-Calcr signaling in the MPOA at least partially mediates risk-taking maternal care, possibly via modified connectomics of Calcr+ neurons postpartum.

Local circuit allowing hypothalamic control of hippocampal area CA2 activity and consequences for CA1.

The hippocampus is critical for memory formation. The hypothalamic supramammillary nucleus (SuM) sends long-range projections to hippocampal area CA2. While the SuM-CA2 connection is critical for social memory, how this input acts on the local circuit is unknown. Using transgenic mice, we found that SuM axon stimulation elicited mixed excitatory and inhibitory responses in area CA2 pyramidal neurons (PNs). Parvalbumin-expressing basket cells were largely responsible for the feedforward inhibitory drive of SuM over area CA2. Inhibition recruited by the SuM input onto CA2 PNs increased the precision of action potential firing both in conditions of low and high cholinergic tone. Furthermore, SuM stimulation in area CA2 modulated CA1 activity, indicating that synchronized CA2 output drives a pulsed inhibition in area CA1. Hence, the network revealed here lays basis for understanding how SuM activity directly acts on the local hippocampal circuit to allow social memory encoding.

Biosynthesis of Mycotoxin Fusaric Acid and Application of a PLP-Dependent Enzyme for Chemoenzymatic Synthesis of Substituted l-Pipecolic Acids.

Fusaric acid (FA) is a well-known mycotoxin that plays an important role in plant pathology. The biosynthetic gene cluster for FA has been identified, but the biosynthetic pathway remains unclarified. Here, we elucidated the biosynthesis of FA, which features a two-enzyme catalytic cascade, a pyridoxal 5'-phosphate (PLP)-dependent enzyme (Fub7), and a flavin mononucleotide (FMN)-dependent oxidase (Fub9) in synthesizing the picolinic acid scaffold. FA biosynthesis also involves an off-line collaboration between a highly reducing polyketide synthase (HRPKS, Fub1) and a nonribosomal peptide synthetase (NRPS)-like carboxylic acid reductase (Fub8) in making an aliphatic α,ß-unsaturated aldehyde. By harnessing the stereoselective C-C bond-forming activity of Fub7, we established a chemoenzymatic route for stereoconvergent synthesis of a series of 5-alkyl-, 5,5-dialkyl-, and 5,5,6-trialkyl-l-pipecolic acids of high diastereomeric ratio.

A hypothalamic novelty signal modulates hippocampal memory.

The ability to recognize information that is incongruous with previous experience is critical for survival. Novelty signals have therefore evolved in the mammalian brain to enhance attention, perception and memory1,2. Although the importance of regions such as the ventral tegmental area3,4 and locus coeruleus5 in broadly signalling novelty is well-established, these diffuse monoaminergic transmitters have yet to be shown to convey specific information on the type of stimuli that drive them. Whether distinct types of novelty, such as contextual and social novelty, are differently processed and routed in the brain is unknown. Here we identify the supramammillary nucleus (SuM) as a novelty hub in the hypothalamus6. The SuM region is unique in that it not only responds broadly to novel stimuli, but also segregates and selectively routes different types of information to discrete cortical targets-the dentate gyrus and CA2 fields of the hippocampus-for the modulation of mnemonic processing. Using a new transgenic mouse line, SuM-Cre, we found that SuM neurons that project to the dentate gyrus are activated by contextual novelty, whereas the SuM-CA2 circuit is preferentially activated by novel social encounters. Circuit-based manipulation showed that divergent novelty channelling in these projections modifies hippocampal contextual or social memory. This content-specific routing of novelty signals represents a previously unknown mechanism that enables the hypothalamus to flexibly modulate select components of cognition.

Understanding the impact of COVID-19 intervention policies on the hospitality labor market.

Using new high-frequency data that covers a representative sample of small businesses in the United States, this study investigates the effects of the COVID-19 pandemic and the resulting state policies on the hospitality industry. First, business closure policies are associated with a 20-30% reduction of non-salaried workers in the food/drink and leisure/entertainment sectors during March-April of 2020. Second, business reopening policies play a statistically significant role in slowly reviving the labor market. Third, considerable differences exist in the impact of policies on the labor market by state. Fourth, the rise of new COVID-19 cases on a daily basis is associated with the continued deterioration of the labor market. Lastly, managerial, practical, and economic implications are described.

Diffusible GRAPHIC to visualize morphology of cells after specific cell-cell contact.

The ability to identify specific cell-cell contact in the highly heterogeneous mammalian body is crucial to revealing precise control of the body plan and correct function. To visualize local connections, we previously developed a genetically encoded fluorescent indicator, GRAPHIC, which labels cell-cell contacts by restricting the reconstituted green fluorescent protein (GFP) signal to the contact site. Here, we modify GRAPHIC to give the reconstituted GFP motility within the membrane, to detect cells that make contact with other specific cells. Removal of leucine zipper domains, located between the split GFP fragment and glycophosphatidylinositol anchor domain, allowed GFP reconstituted at the contact site to diffuse throughout the entire plasma membrane, revealing cell morphology. Further, depending on the structural spacers employed, the reconstituted GFP could be selectively targeted to N terminal (NT)- or C terminal (CT)-probe-expressing cells. Using these novel constructs, we demonstrated that we can specifically label NT-probe-expressing cells that made contact with CT-probe-expressing cells in an epithelial cell culture and in Xenopus 8-cell-stage blastomeres. Moreover, we showed that diffusible GRAPHIC (dGRAPHIC) can be used in neuronal circuits to trace neurons that make contact to reveal a connection map. Finally, application in the developing brain demonstrated that the dGRAPHIC signal remained on neurons that had transient contacts during circuit development to reveal the contact history. Altogether, dGRAPHIC is a unique probe that can visualize cells that made specific cell-cell contact.

Biosynthesis of Amino Acid Derived α-Pyrones by an NRPS-NRPKS Hybrid Megasynthetase in Fungi.

A nonribosomal peptide synthetase (NRPS)-nonreducing polyketide synthase (NRPKS) hybrid enzyme (AnATPKS) from Aspergillus niger was shown to produce amino acid derived α-pyrone natural products (pyrophen and campyrone B). Biochemical characterization of the NRPS module in vitro reveals that the adenylation domain is promiscuous toward a variety of substituted phenylalanine analogues. Using precursor feeding and heterologous expression of AnATPKS and an associated O-methyltransferase (AnOMT), we were able to access a library of substituted pyrophen analogues. Our study paves the way for future combinatorial biosynthesis of diverse α-pyrone natural products using NRPS-NRPKS hybrids.

Structure-guided function discovery of an NRPS-like glycine betaine reductase for choline biosynthesis in fungi.

Nonribosomal peptide synthetases (NRPSs) and NRPS-like enzymes have diverse functions in primary and secondary metabolisms. By using a structure-guided approach, we uncovered the function of a NRPS-like enzyme with unusual domain architecture, catalyzing two sequential two-electron reductions of glycine betaine to choline. Structural analysis based on the homology model suggests cation-π interactions as the major substrate specificity determinant, which was verified using substrate analogs and inhibitors. Bioinformatic analysis indicates this NRPS-like glycine betaine reductase is highly conserved and widespread in kingdom fungi. Genetic knockout experiments confirmed its role in choline biosynthesis and maintaining glycine betaine homeostasis in fungi. Our findings demonstrate that the oxidative choline-glycine betaine degradation pathway can operate in a fully reversible fashion and provide insight in understanding fungal choline metabolism. The use of an NRPS-like enzyme for reductive choline formation is energetically efficient compared with known pathways. Our discovery also underscores the capabilities of the structure-guided approach in assigning functions of uncharacterized multidomain proteins, which can potentially aid functional discovery of new enzymes by genome mining.

Routing Hippocampal Information Flow through Parvalbumin Interneuron Plasticity in Area CA2.

The hippocampus is critical for the formation of episodic memory. It is, therefore, important to understand intra-hippocampal circuitry, especially in the often overlooked area CA2. Using specific transgenic mouse lines combined with opto- and chemogenetics, we show that local plasticity of parvalbumin-expressing interneurons in area CA2 allows CA3 input to recruit CA2 pyramidal neurons (PNs), thereby increasing the excitatory drive between CA3 and CA1. CA2 PNs provide both stronger excitation and larger feed-forward inhibition onto deep, compared with superficial, CA1 PNs. This feed-forward inhibition, largely mediated by parvalbumin-expressing interneurons, normalizes the excitatory drive onto deep and superficial CA1 PNs. Finally, we identify a target of CA2 in area CA1, i.e., CA1 PNs, whose soma are located in stratum radiatum. These data provide insight into local hippocampal circuitry and reveal how localized plasticity can potentially control information flow in the larger hippocampal network.

Genetically Encoded Fluorescent Indicator GRAPHIC Delineates Intercellular Connections.

Intercellular contacts are essential for precise organ morphogenesis, function, and maintenance; however, spatiotemporal information of cell-cell contacts or adhesions remains elusive in many systems. We developed a genetically encoded fluorescent indicator for intercellular contacts with optimized intercellular GFP reconstitution using glycosylphosphatidylinositol (GPI) anchor, GRAPHIC (GPI anchored reconstitution-activated proteins highlight intercellular connections), which can be used for an expanded number of cell types. We observed a robust GFP signal specifically at the interface between cultured cells, without disrupting natural cell contact. Application of GRAPHIC to the fish retina specifically delineated cone-bipolar connection sites. Moreover, we showed that GRAPHIC can be used in the mouse central nervous system to delineate synaptic sites in the thalamocortical circuit. Finally, we generated GRAPHIC color variants, enabling detection of multiple convergent contacts simultaneously in cell culture system. We demonstrated that GRAPHIC has high sensitivity and versatility, which will facilitate the analysis of the complex multicellular connections without previous limitations.