Brain circuits for retching-like behavior.

Nausea and vomiting are important defensive responses to cope with pathogens and toxins that invade the body. The nucleus of the solitary tract (NTS) is important for initiating these responses. However, the molecular heterogeneities and cellular diversities of the NTS occlude a better understanding of these defensive responses. Here, we constructed the single-nucleus transcriptomic atlas of NTS cells and found multiple populations of NTS neurons that may be involved in these defensive responses. Among these, we identified Calbindin1-positive (Calb1+) NTS neurons that are molecularly distinct from Tac1+ neurons. These Calb1+ neurons are critical for nausea and retching induced by cereulide; an emetic toxin secreted by Bacillus Cereus. Strikingly, we found that cereulide can directly modulate vagal sensory neurons that innervate Calb1+ NTS neurons, a novel mechanism distinct from that for nausea and retching induced by Staphylococcal enterotoxin A. Together, our transcriptomic atlas of NTS neurons and the functional analyses revealed the neural mechanism for cereulide-induced retching-like behavior. These results demonstrate the molecular and cellular complexities in the brain that underlie defensive responses to the diversities of pathogens and toxins.

The gut-to-brain axis for toxin-induced defensive responses.

After ingestion of toxin-contaminated food, the brain initiates a series of defensive responses (e.g., nausea, retching, and vomiting). How the brain detects ingested toxin and coordinates diverse defensive responses remains poorly understood. Here, we developed a mouse-based paradigm to study defensive responses induced by bacterial toxins. Using this paradigm, we identified a set of molecularly defined gut-to-brain and brain circuits that jointly mediate toxin-induced defensive responses. The gut-to-brain circuit consists of a subset of Htr3a+ vagal sensory neurons that transmit toxin-related signals from intestinal enterochromaffin cells to Tac1+ neurons in the dorsal vagal complex (DVC). Tac1+ DVC neurons drive retching-like behavior and conditioned flavor avoidance via divergent projections to the rostral ventral respiratory group and lateral parabrachial nucleus, respectively. Manipulating these circuits also interferes with defensive responses induced by the chemotherapeutic drug doxorubicin. These results suggest that food poisoning and chemotherapy recruit similar circuit modules to initiate defensive responses.

Mechanically evoked defensive attack is controlled by GABAergic neurons in the anterior hypothalamic nucleus.

Innate defensive behaviors triggered by environmental threats are important for animal survival. Among these behaviors, defensive attack toward threatening stimuli (for example, predators) is often the last line of defense. How the brain regulates defensive attack remains poorly understood. Here we show that noxious mechanical force in an inescapable context is a key stimulus for triggering defensive attack in laboratory mice. Mechanically evoked defensive attacks were abrogated by photoinhibition of vGAT+ neurons in the anterior hypothalamic nucleus (AHN). The vGAT+ AHN neurons encoded the intensity of mechanical force and were innervated by brain areas relevant to pain and attack. Activation of these neurons triggered biting attacks toward a predator while suppressing ongoing behaviors. The projection from vGAT+ AHN neurons to the periaqueductal gray might be one AHN pathway participating in mechanically evoked defensive attack. Together, these data reveal that vGAT+ AHN neurons encode noxious mechanical stimuli and regulate defensive attack in mice.

A brain-to-spinal sensorimotor loop for repetitive self-grooming.

Self-grooming is a complex behavior with important biological functions and pathological relevance. How the brain coordinates with the spinal cord to generate the repetitive movements of self-grooming remains largely unknown. Here, we report that in the caudal part of the spinal trigeminal nucleus (Sp5C), neurons that express Cerebellin-2 (Cbln2+) form a neural circuit to the cervical spinal cord to maintain repetitive orofacial self-grooming. Inactivation of Cbln2+ Sp5C neurons blocked both sensory-evoked and stress-induced repetitive orofacial self-grooming. Activation of these neurons triggered short-latency repetitive forelimb movements that resembled orofacial self-grooming. The Cbln2+ Sp5C neurons were monosynaptically innervated by both somatosensory neurons in the trigeminal ganglion and paraventricular hypothalamic neurons. Among the divergent projections of Cbln2+ Sp5C neurons, a descending pathway that innervated motor neurons and interneurons in the cervical spinal cord was necessary and sufficient for repetitive orofacial self-grooming. These data reveal a brain-to-spinal sensorimotor loop for repetitive self-grooming in mice.

The tectonigral pathway regulates appetitive locomotion in predatory hunting in mice.

Appetitive locomotion is essential for animals to approach rewards, such as food and prey. The neuronal circuitry controlling appetitive locomotion is unclear. In a goal-directed behavior-predatory hunting, we show an excitatory brain circuit from the superior colliculus (SC) to the substantia nigra pars compacta (SNc) to enhance appetitive locomotion in mice. This tectonigral pathway transmits locomotion-speed signals to dopamine neurons and triggers dopamine release in the dorsal striatum. Synaptic inactivation of this pathway impairs appetitive locomotion but not defensive locomotion. Conversely, activation of this pathway increases the speed and frequency of approach during predatory hunting, an effect that depends on the activities of SNc dopamine neurons. Together, these data reveal that the SC regulates locomotion-speed signals to SNc dopamine neurons to enhance appetitive locomotion in mice.

Transcriptomic encoding of sensorimotor transformation in the midbrain.

Sensorimotor transformation, a process that converts sensory stimuli into motor actions, is critical for the brain to initiate behaviors. Although the circuitry involved in sensorimotor transformation has been well delineated, the molecular logic behind this process remains poorly understood. Here, we performed high-throughput and circuit-specific single-cell transcriptomic analyses of neurons in the superior colliculus (SC), a midbrain structure implicated in early sensorimotor transformation. We found that SC neurons in distinct laminae expressed discrete marker genes. Of particular interest, Cbln2 and Pitx2 were key markers that define glutamatergic projection neurons in the optic nerve (Op) and intermediate gray (InG) layers, respectively. The Cbln2+ neurons responded to visual stimuli mimicking cruising predators, while the Pitx2+ neurons encoded prey-derived vibrissal tactile cues. By forming distinct input and output connections with other brain areas, these neuronal subtypes independently mediated behaviors of predator avoidance and prey capture. Our results reveal that, in the midbrain, sensorimotor transformation for different behaviors may be performed by separate circuit modules that are molecularly defined by distinct transcriptomic codes.

The influential factors and intervention strategies that engage malignant cancer patients in health-promoting behaviors during PICC line maintenance.

OBJECTIVE: To analyze the influential factors and intervention strategies involved in engaging health-promoting behaviors (EHPD) during peripheral central venous catheter (PICC) line maintenance in malignant tumor patients. METHODS: 120 patients with malignant tumors who underwent PICC line maintenance in our hospital were prospectively analyzed. They were divided into a low and moderate level group (HPLP-II score ≤137) and a high level group (HPLP-II score >137) according to their Health Promoting Lifestyle Profile II (HPLP-II) questionnaire scores. Single-factor and multifactor analyses were performed to identify the factors influencing the patients' engagement in self-health-promoting behaviors. The one hundred and twenty patients with malignant tumors were randomly divided into two groups (n=60 in each group). The control group and the intervention group underwent routine nursing care and patient education. The two groups were compared in terms of the changes in their HPLP-II scores, their Cancer Patients PICC Self-management Scale (CPPSM) scores, their SAS and their SDS scores before and after the intervention, as well as their maintenance compliance rates, their complication rates during catheter placement, and their lack of PICC maintenance. RESULTS: Literacy, place of residence, duration of catheter use, self-management abilities of PICCs, social support, and anxiety were risk factors (OR>1, P<0.05). Compared with their pre-intervention scores, the HPLP-II and CPPSM scores were increased in both groups (P<0.05), and the SAS and SDS scores were decreased in both groups after the intervention (P<0.05), and the intervention group had higher scores than the control group (P<0.05). The intervention group exhibited a higher maintenance compliance rate than the control group (P<0.05). The incidence of complications and the lack of PICC maintenance in the intervention group were lower than they were in the control group (P<0.05). CONCLUSION: The influential factors during PICC maintenance for EHPD in malignant cancer patients include literacy, place of residence, duration of PICC use, etc. Patient education can promote patients' EHPD and self-management abilities, relieve their anxiety and depression, reduce their complications, and improve their compliance.

ß-Sitosterol Protects against Myocardial Ischemia/Reperfusion Injury via Targeting PPARγ/NF-κB Signalling.

Myocardial ischemia/reperfusion (I/R) injury is a clinically severe complication, which can cause high rates of disability and mortality particularly in patients with myocardial infarction, yet the molecular mechanisms underlying this process remain unclear. This study aimed to explore the protective effects of ß-sitosterol against myocardial I/R injury and to elucidate the underlying molecular mechanisms. Our results showed that hypoxia/reoxygenation (H/R) treatment suppressed cell viability, induced cell apoptosis and reactive oxygen species production, increased caspase-3 and -9 activities, upregulated caspase-3 and -9 protein expressions, downregulated the Bcl-2 protein expression, and reduced the mitochondrial membrane potential. ß-Sitosterol treatment attenuated H/R-induced cardiomyocyte injury. Moreover, ß-sitosterol treatment counteracted the inhibitory effects of H/R treatment on the peroxisome proliferator-activated receptor gamma (PPARγ) expression and enhanced effects of H/R treatment on the NF-κB expression in cardiomyocytes. Furthermore, inhibition of PPARγ impaired the protective actions of ß-sitosterol against H/R-induced cardiomyocyte injury. In the I/R rats, ß-sitosterol treatment reduced the myocardial infarcted size and apoptosis, which was attenuated by the inhibition of PPARγ. In conclusion, our results demonstrate that ß-sitosterol protected against in vitro H/R-induced cardiomyocyte injury and in vivo myocardial I/R injury. The ß-sitosterol-mediated cardioprotective effects may involve the modulation of PPARγ/NF-κB signalling during myocardial I/R injury. Further studies are required to further explore the clinical application of ß-sitosterol in the myocardial I/R injury.

A subcortical excitatory circuit for sensory-triggered predatory hunting in mice.

Predatory hunting plays a fundamental role in animal survival. Little is known about the neural circuits that convert sensory cues into neural signals to drive this behavior. Here we identified an excitatory subcortical neural circuit from the superior colliculus to the zona incerta that triggers predatory hunting. The superior colliculus neurons that form this pathway integrate motion-related visual and vibrissal somatosensory cues of prey. During hunting, these neurons send out neural signals that are temporally correlated with predatory attacks, but not with feeding after prey capture. Synaptic inactivation of this pathway selectively blocks hunting for prey without impairing other sensory-triggered behaviors. These data reveal a subcortical neural circuit that is specifically engaged in translating sensory cues into neural signals to provoke predatory hunting.

Clinical efficacy of metronomic chemotherapy after cool-tip radiofrequency ablation in the treatment of hepatocellular carcinoma.

PURPOSE: Anti-angiogenic agents have shown promise for treating advanced hepatocellular carcinoma (HCC), and the primary mechanism of low-dose metronomic chemotherapy using traditional cytotoxic drugs is anti-angiogenic. This study evaluated the efficacy of metronomic capecitabine and thalidomide after cool-tip radiofrequency ablation (RFA), relative to RFA alone, for treating patients with HCC. METHODS AND MATERIALS: Patients with HCC were randomly apportioned to a test group (n = 22) receiving metronomic chemotherapy with capecitabine and thalidomide after RFA, or a control group (n = 28) receiving RFA only. Serum circulating endothelial cells (CECs) and vascular endothelial growth factor (VEGF) were measured in all patients before and 1 month after RFA treatment. Enhanced computed tomography or ultrasound imaging was performed to evaluate efficacy during 12 months of follow-up. The treatment groups were further stratified as HCC within or outside the Milan criteria for transplantation. RESULTS: One month post-treatment, the tumour response rate (TRR), including complete response and partial response rate, of the test and control groups was statistically similar. At 12 months, the TRR of the test group (68.2%) was significantly higher than that of the control group (35.7%). In the test group, the TRR of patients whose tumour burdens were outside the Milan criteria was significantly higher than that of the control group. One month post-treatment, CECs and VEGF levels of the test group were significantly lower than baseline, while those of the control group were significantly higher. At the end of the 12-month follow-up, there was a progression-free survival (PFS) benefit of 2 months in the test group. CONCLUSION: Metronomic capecitabine and thalidomide after RFA significantly reduced recurrence of HCC and extended PFS, especially for HCC outside the Milan criteria, perhaps via reduction of serum CECs and VEGF levels and inhibition of tumour angiogenesis.