Cornelia de Lange syndrome (CdLS) is a rare multisystem disorder with specific dysmorphic features. Pathogenic genetic variants encoding cohesion complex subunits and interacting proteins (e.g., ...NIPBL, SMC1A, SMC3, HDAC8, and RAD21) are the major causes of CdLS. However, there are many clinically diagnosed cases of CdLS without pathogenic variants in these genes. To identify further genetic causes of CdLS, we performed whole-exome sequencing in 57 CdLS families, systematically evaluating both single nucleotides variants (SNVs) and copy number variations (CNVs). We identified pathogenic genetic changes in 36 out of 57 (63.2 %) families, including 32 SNVs and four CNVs. Two known CdLS genes, NIPBL and SMC1A, were mutated in 23 and two cases, respectively. Among the remaining 32 individuals, four genes (ANKRD11, EP300, KMT2A, and SETD5) each harbored a pathogenic variant in a single individual. These variants are known to be involved in CdLS-like. Furthermore, pathogenic CNVs were detected in NIPBL, MED13L, and EHMT1, along with pathogenic SNVs in ZMYND11, MED13L, and PHIP. These three latter genes were involved in diseases other than CdLS and CdLS-like. Systematic clinical evaluation of all patients using a recently proposed clinical scoring system showed that ZMYND11, MED13L, and PHIP abnormality may cause CdLS or CdLS-like.
Abstract We tested the hypothesis that the effects of food restriction on behavioral motivation are mediated by one or both of the RFamides, RFamide-related Peptide-3 (RFRP-3) and kisspeptin (Kp) in ...female Syrian hamsters ( Mesocricetus auratus ). Female hamsters fed ad libitum and given a choice between food and adult male hamsters are highly motivated to visit males instead of food on all four days of the estrous cycle, but after 8 days of mild food restriction (75% of ad libitum intake) they shift their preference toward food every day of the estrous cycle until the day of estrus, when they shift their preference back toward the males. In support of a role for RFRP-3 in these behavioral changes, the preference for food and the activation of RFRP-3-immunoreactive (Ir) cells in the dorsomedial hypothalamus (DMH) showed the same estrous cycle pattern in food-restricted females, but no association was observed between behavior and the activation of Kp cells in the hypothalamic arcuate nucleus or preoptic area. Next, we tested the hypothesis that food-restriction-induced activation of RFRP-3-Ir cells is modulated by high levels of ovarian steroids at the time of estrus. In support of this idea, on nonestrous days, mild food restriction increased activation of RFRP-3-Ir cells, but failed to do so on the day of estrus even though this level of food restriction did not significantly decrease circulating concentrations of estradiol or progesterone. Furthermore, in ovariectomized females, food-restriction-induced increases in activation of RFRP-3-Ir cells were blocked by systemic treatment with progesterone alone, estradiol plus progesterone, but not estradiol alone. Central infusion with RFRP-3 in ad libitum -fed females significantly decreased sexual motivation and produced significant increases in 90-minute food hoarding, in support of the hypothesis that elevated central levels of RFRP-3 are sufficient to create the shift in behavioral motivation in females fed ad libitum . Together, these results are consistent with the hypothesis that high levels of ingestive motivation are promoted during the nonfertile phase of the estrous cycle by elevated activation of RFRP-3-Ir cells, and RFRP-3-Ir cellular activation is modulated by ovarian steroids around the time of estrus, thereby diverting attention away from food and increasing sexual motivation.
The current opioid epidemic has dramatically increased the number of children who are prenatally exposed to opioids, including oxycodone. A number of social and cognitive abnormalities have been ...documented in these children as they reach young adulthood. However, little is known about the mechanisms underlying developmental effects of prenatal opioid exposure. Microglia, the resident immune cells of the brain, respond to acute opioid exposure in adulthood. Moreover, microglia are known to sculpt neural circuits during typical development. Indeed, we recently found that microglial phagocytosis of dopamine D1 receptors (D1R) in the nucleus accumbens (NAc) is required for the natural developmental decline in NAc-D1R that occurs between adolescence and adulthood in rats. This microglial pruning occurs only in males, and is required for the normal developmental trajectory of social play behavior. However, virtually nothing is known as to whether this developmental program is altered by prenatal exposure to opioids. Here, we show in rats that maternal oxycodone self-administration during pregnancy leads to reduced adolescent microglial phagocytosis of D1R and subsequently higher D1R density within the NAc in adult male, but not female, offspring. Finally, we show prenatal and adult behavioral deficits in opioid-exposed offspring, including impaired extinction of oxycodone-conditioned place preference in males. This work demonstrates for the first time that microglia play a key role in translating prenatal opioid exposure to changes in neural systems and behavior.
Antagonism of nicotinic acetylcholine receptors (nAChRs) in the medial habenula (MHb) or interpeduncular nucleus (IPN) triggers withdrawal-like behaviors in mice chronically exposed to nicotine, ...implying that nicotine dependence involves the sensitization of nicotinic signaling. Identification of receptor and/or neurophysiological mechanisms underlying this sensitization is important, as it could promote novel therapeutic strategies to reduce tobacco use. Using an approach involving photoactivatable nicotine, we previously demonstrated that chronic nicotine (cNIC) potently enhances nAChR function in dendrites of MHb neurons. However, whether cNIC modulates downstream components of the habenulo-interpeduncular (Hb-IP) circuit is unknown. In this study, cNIC-mediated changes to Hb-IP nAChR function were examined in mouse (male and female) brain slices using molecular, electrophysiological, and optical techniques. cNIC enhanced action potential firing and modified spike waveform characteristics in MHb neurons. Nicotine uncaging revealed nAChR functional enhancement by cNIC on proximal axonal membranes. Similarly, nAChR-driven glutamate release from MHb axons was enhanced by cNIC. In IPN, the target structure of MHb axons, neuronal morphology, and nAChR expression is complex, with stronger nAChR function in the rostral subnucleus rostral IPN (IPR). As in MHb, cNIC induced strong upregulation of nAChR function in IPN neurons. This, coupled with cNIC-enhanced nicotine-stimulated glutamate release, was associated with stronger depolarization responses to brief (1 ms) nicotine uncaging adjacent to IPR neurons. Together, these results indicate that chronic exposure to nicotine dramatically alters nicotinic cholinergic signaling and cell excitability in Hb-IP circuits, a key pathway involved in nicotine dependence.
This study uncovers several neuropharmacological alterations following chronic exposure to nicotine in a key brain circuit involved in nicotine dependence. These results suggest that smokers or regular users of electronic nicotine delivery systems (i.e., "e-cigarettes") likely undergo sensitization of cholinergic circuitry in the Hb-IP system. Reducing the activity of Hb-IP nAChRs, either volitionally during smoking cessation or inadvertently via receptor desensitization during nicotine intake, may be a key trigger of withdrawal in nicotine dependence. Escalation of nicotine intake in smokers, or tolerance, may involve stimulation of these sensitized cholinergic pathways. Smoking cessation therapeutics are only marginally effective, and by identifying cellular/receptor mechanisms of nicotine dependence, our results take a step toward improved therapeutic approaches for this disorder.
Ventral tegmental area (VTA) glutamate neurons are important components of reward circuitry, but whether they are subject to cholinergic modulation is unknown. To study this, we used molecular, ...physiological, and photostimulation techniques to examine nicotinic acetylcholine receptors (nAChRs) in VTA glutamate neurons. Cells in the medial VTA, where glutamate neurons are enriched, are responsive to acetylcholine (ACh) released from cholinergic axons. VTA VGLUT2+ neurons express mRNA and protein subunits known to comprise heteromeric nAChRs. Electrophysiology, coupled with two-photon microscopy and laser flash photolysis of photoactivatable nicotine, was used to demonstrate nAChR functional activity in the somatodendritic subcellular compartment of VTA VGLUT2+ neurons. Finally, optogenetic isolation of intrinsic VTA glutamatergic microcircuits along with gene-editing techniques demonstrated that nicotine potently modulates excitatory transmission within the VTA via heteromeric nAChRs. These results indicate that VTA glutamate neurons are modulated by cholinergic mechanisms and participate in the cascade of physiological responses to nicotine exposure.
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•VTA glutamate neurons are integrated into cholinergic circuits•Functional heteromeric nAChRs are expressed in VTA glutamate neurons•nAChRs modulate glutamate transmission in VTA microcircuits•β2 nAChRs are required for nicotine modulation of glutamate transmission
Yan et al. examine how functional activity of nicotinic cholinergic receptors is distributed in diverse VTA cell types, revealing nAChR activity in VTA glutamate neurons. These receptors modulate local glutamate transmission in VTA, suggesting mechanisms by which nicotine influences mesolimbic circuitry.
Opioid use disorder (OUD) has a variety of adverse effects on both the users and their offspring. In the current study, a random group of Sprague-Dawley rats (25 females and 15 males) were tested for ...intravenous self-administration of the opioid agonist remifentanil to determine the range of acquisition for opioid. One-month after the end of self-administration of remifentanil, rats with the highest intake were mated together and rats with lowest intake were mated together. Then, the offspring of the two groups were tested for anxiety-like behavior, locomotor activity, nociception and intravenous remifentanil self-administration. The parents showed a range of remifentanil self-administration, especially in the female rats. The offspring of the parents with low and high remifentanil self-administration showed significant differences in specific behavioral functions. On the hotplate test of nociception, the female offspring parents with high remifentanil self-administration had significantly longer hotplate latencies, indicating reduced nociception, than the female offspring of parents with low remifentanil-self-administration, whereas there was no difference in the male offspring of low and high responding parents. In the elevated plus maze test of anxiety-like behavior, the offspring of the parents with high remifentanil intake showed more anxiety-like behavior than the offspring of the parents with low remifentanil intake regardless of sex. Locomotor activity was not significantly different. Interestingly, no significant differences in remifentanil self-administration in the offspring of parents with low and high remifentanil self-administration were detected. Overall, our data suggest a considerable range in remifentanil self-administration in rats and the offspring of rats with high opioid self-administration exhibit different behaviors vs offspring of rats with low opioid self-administration.
Many tobacco smokers consume nicotine intermittently, but the underlying mechanisms and neurobiological changes associated with intermittent nicotine intake are unclear. Understanding intermittent ...nicotine intake is a high priority, as it could promote therapeutic strategies to attenuate tobacco consumption. We examined nicotine intake behavior and neurobiological changes in male rats that were trained to self-administer nicotine during brief (5 min) trials interspersed with longer (15 min) drug-free periods. Rats readily adapted to intermittent access (IntA) SA following acquisition on a continuous access (ContA) schedule. Probabilistic analysis of IntA nicotine SA suggested reduced nicotine loading behavior compared to ContA, and nicotine pharmacokinetic modeling revealed that rats taking nicotine intermittently may have increased intake to maintain blood levels of nicotine that are comparable to ContA SA. After IntA nicotine SA, rats exhibited an increase in unreinforced responses for nicotine-associated cues (incubation of craving) and specific alterations in the striatal proteome after 7 days without nicotine. IntA nicotine SA also induced nAChR functional upregulation in the interpeduncular nucleus (IPN), and it enhanced nicotine binding in the brain as determined via 11Cnicotine positron emission tomography. Reducing the saliency of the cue conditions during the 5 min access periods attenuated nicotine intake, but incubation of craving was preserved. Together, these results indicate that IntA conditions promote nicotine SA and nicotine seeking after a nicotine-free period.
•Rats participate in nicotine self-administration under intermittent access conditions.•Intermittent nicotine self-administration leads to incubation of craving after a 7-day nicotine-free period.•Intermittent nicotine self-administration is associated with changes in nicotinic receptors in multiple brain areas.
ObjectiveTo investigate healthcare professional staff and students’ perception of wearing surgical masks before and after their experience with the COVID-19 pandemic, and to evaluate the impact on ...mask wearing behaviour in future influenza seasons.DesignCross-sectional study using anonymous survey.Setting and participantsHealthcare students and staff from a healthcare academic institution in Southern California participated in the mask survey study. Survey results were collected from June to November 2021. A total of 305 respondents responded to the survey, with 173 being healthcare students and 132 being working healthcare staff.OutcomesThe study examined respondents’ perceptions and hospital mask wearing behaviour before and after their COVID-19 pandemic experience, as well as during previous and future influenza seasons.ResultsTwo hundred and sixty-four (86.6%) respondents agreed that wearing a surgical mask reduces infection and limits transmission of infectious disease, yet prior to the pandemic, only a small proportion wore a mask in the hospital or during patient care. After experiencing the COVID-19 pandemic, more respondents indicated that they would continue to wear a mask when they are in a hospital in general (n=145, 47.5%), during patient care (n=262, 85.9%), during influenza seasons throughout the hospital (n=205, 67.2%) and during influenza seasons during patient care (n=270, 88.5%).ConclusionThe pandemic experience has greatly influenced the health prevention behaviours of healthcare students and staff. After the pandemic, many respondents will continue to practice surgical mask wearing behaviour in the hospital, especially during face-to-face patient care. This demonstrates a significant change in health prevention perceptions among the current and the future generation of healthcare professionals.
Nicotinic acetylcholine receptors (nAChRs), prototype members of the cys‐loop ligand‐gated ion channel family, are key mediators of cholinergic transmission in the central nervous system. Despite ...their importance, technical gaps exist in our ability to dissect the function of individual subunits in the brain. To overcome these barriers, we designed CRISPR/Cas9 small guide RNA sequences (sgRNAs) for the production of loss‐of‐function alleles in mouse nAChR genes. These sgRNAs were validated in vitro via deep sequencing. We subsequently targeted candidate nAChR genes in vivo by creating herpes simplex virus (HSV) vectors delivering sgRNAs and Cas9 expression to mouse brain. The production of loss‐of‐function insertions or deletions (indels) by these ‘all‐in‐one’ HSV vectors was confirmed using brain slice patch clamp electrophysiology coupled with pharmacological analysis. Next, we developed a scheme for cell type‐specific gene editing in mouse brain. Knockin mice expressing Cas9 in a Cre‐dependent manner were validated using viral microinjections and genetic crosses to common Cre‐driver mouse lines. We subsequently confirmed functional Cas9 activity by targeting the ubiquitous neuronal protein, NeuN, using adeno‐associated virus (AAV) delivery of sgRNAs. Finally, the mouse β2 nAChR gene was successfully targeted in dopamine transporter (DAT)‐positive neurons via CRISPR/Cas9. The sgRNA sequences and viral vectors, including our scheme for Cre‐dependent gene editing, should be generally useful to the scientific research community. These tools could lead to new discoveries related to the function of nAChRs in neurotransmission and behavioral processes.
Peng et al. introduce a set of viral vectors for nicotinic acetylcholine receptor (nAChR) gene editing. Herpes simplex virus vectors allow all‐in‐one delivery of CRISPR/Cas9 elements for gene editing in any mouse strain, and adeno‐associated virus vectors allow cell type‐specific nAChR gene editing. These vectors will be useful for next‐generation molecular‐level queries into the contribution of nAChR subunits in addiction and psychiatric disorders.
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