Astrocytes Assemble Thalamocortical Synapses by Bridging NRX1α and NL1 via Hevin.

Proper establishment of synapses is critical for constructing functional circuits. Interactions between presynaptic neurexins and postsynaptic neuroligins coordinate the formation of synaptic adhesions. An isoform code determines the direct interactions of neurexins and neuroligins across the synapse. However, whether extracellular linker proteins can expand such a code is unknown. Using a combination of in vitro and in vivo approaches, we found that hevin, an astrocyte-secreted synaptogenic protein, assembles glutamatergic synapses by bridging neurexin-1alpha and neuroligin-1B, two isoforms that do not interact with each other. Bridging of neurexin-1alpha and neuroligin-1B via hevin is critical for the formation and plasticity of thalamocortical connections in the developing visual cortex. These results show that astrocytes promote the formation of synapses by modulating neurexin/neuroligin adhesions through hevin secretion. Our findings also provide an important mechanistic insight into how mutations in these genes may lead to circuit dysfunction in diseases such as autism.

Dectin-1 limits autoimmune neuroinflammation and promotes myeloid cell-astrocyte crosstalk via Card9-independent expression of Oncostatin M.

Pathologic roles of innate immunity in neurologic disorders are well described, but their beneficial aspects are less understood. Dectin-1, a C-type lectin receptor (CLR), is largely known to induce inflammation. Here, we report that Dectin-1 limited experimental autoimmune encephalomyelitis (EAE), while its downstream signaling molecule, Card9, promoted the disease. Myeloid cells mediated the pro-resolution function of Dectin-1 in EAE with enhanced gene expression of the neuroprotective molecule, Oncostatin M (Osm), through a Card9-independent pathway, mediated by the transcription factor NFAT. Furthermore, we find that the Osm receptor (OsmR) functioned specifically in astrocytes to reduce EAE severity. Notably, Dectin-1 did not respond to heat-killed Mycobacteria, an adjuvant to induce EAE. Instead, endogenous Dectin-1 ligands, including galectin-9, in the central nervous system (CNS) were involved to limit EAE. Our study reveals a mechanism of beneficial myeloid cell-astrocyte crosstalk regulated by a Dectin-1 pathway and identifies potential therapeutic targets for autoimmune neuroinflammation.

A monoclonal antibody that targets a NaV1.7 channel voltage sensor for pain and itch relief.

Voltage-gated sodium (NaV) channels control the upstroke of the action potentials in excitable cells. Multiple studies have shown distinct roles of NaV channel subtypes in human physiology and diseases, but subtype-specific therapeutics are lacking and the current efforts have been limited to small molecules. Here, we present a monoclonal antibody that targets the voltage-sensor paddle of NaV1.7, the subtype critical for pain sensation. This antibody not only inhibits NaV1.7 with high selectivity, but also effectively suppresses inflammatory and neuropathic pain in mice. Interestingly, the antibody inhibits acute and chronic itch despite well-documented differences in pain and itch modulation. Using this antibody, we discovered that NaV1.7 plays a key role in spinal cord nociceptive and pruriceptive synaptic transmission. Our studies reveal that NaV1.7 is a target for itch management, and the antibody has therapeutic potential for suppressing pain and itch. Our antibody strategy may have broad applications for voltage-gated cation channels.

STING controls nociception via type I interferon signalling in sensory neurons.

The innate immune regulator STING is a critical sensor of self- and pathogen-derived DNA. DNA sensing by STING leads to the induction of type-I interferons (IFN-I) and other cytokines, which promote immune-cell-mediated eradication of pathogens and neoplastic cells1,2. STING is also a robust driver of antitumour immunity, which has led to the development of STING activators and small-molecule agonists as adjuvants for cancer immunotherapy3. Pain, transmitted by peripheral nociceptive sensory neurons (nociceptors), also aids in host defence by alerting organisms to the presence of potentially damaging stimuli, including pathogens and cancer cells4,5. Here we demonstrate that STING is a critical regulator of nociception through IFN-I signalling in peripheral nociceptors. We show that mice lacking STING or IFN-I signalling exhibit hypersensitivity to nociceptive stimuli and heightened nociceptor excitability. Conversely, intrathecal activation of STING produces robust antinociception in mice and non-human primates. STING-mediated antinociception is governed by IFN-Is, which rapidly suppress excitability of mouse, monkey and human nociceptors. Our findings establish the STING-IFN-I signalling axis as a critical regulator of physiological nociception and a promising new target for treating chronic pain.

Specialized Pro-Resolving Mediators as Resolution Pharmacology for the Control of Pain and Itch.

Specialized pro-resolving mediators (SPMs), including resolvins, protectins, and maresins, are endogenous lipid mediators that are synthesized from omega-3 polyunsaturated fatty acids during the acute phase or resolution phase of inflammation. Synthetic SPMs possess broad safety profiles and exhibit potent actions in resolving inflammation in preclinical models. Accumulating evidence in the past decade has demonstrated powerful analgesia of exogenous SPMs in rodent models of inflammatory, neuropathic, and cancer pain. Furthermore, endogenous SPMs are produced by sham surgery and neuromodulation (e.g., vagus nerve stimulation). SPMs produce their beneficial actions through multiple G protein-coupled receptors, expressed by immune cells, glial cells, and neurons. Notably, loss of SPM receptors impairs the resolution of pain. I also highlight the emerging role of SPMs in the control of itch. Pharmacological targeting of SPMs or SPM receptors has the potential to lead to novel therapeutics for pain and itch as emerging approaches in resolution pharmacology.

Deficiency of neutral cholesterol ester hydrolase 1 (NCEH1) impairs endothelial function in diet-induced diabetic mice.

BACKGROUND: Neutral cholesterol ester hydrolase 1 (NCEH1) plays a critical role in the regulation of cholesterol ester metabolism. Deficiency of NCHE1 accelerated atherosclerotic lesion formation in mice. Nonetheless, the role of NCEH1 in endothelial dysfunction associated with diabetes has not been explored. The present study sought to investigate whether NCEH1 improved endothelial function in diabetes, and the underlying mechanisms were explored. METHODS: The expression and activity of NCEH1 were determined in obese mice with high-fat diet (HFD) feeding, high glucose (HG)-induced mouse aortae or primary endothelial cells (ECs). Endothelium-dependent relaxation (EDR) in aortae response to acetylcholine (Ach) was measured. RESULTS: Results showed that the expression and activity of NCEH1 were lower in HFD-induced mouse aortae, HG-exposed mouse aortae ex vivo, and HG-incubated primary ECs. HG exposure reduced EDR in mouse aortae, which was exaggerated by endothelial-specific deficiency of NCEH1, whereas NCEH1 overexpression restored the impaired EDR. Similar results were observed in HFD mice. Mechanically, NCEH1 ameliorated the disrupted EDR by dissociating endothelial nitric oxide synthase (eNOS) from caveolin-1 (Cav-1), leading to eNOS activation and nitric oxide (NO) release. Moreover, interaction of NCEH1 with the E3 ubiquitin-protein ligase ZNRF1 led to the degradation of Cav-1 through the ubiquitination pathway. Silencing Cav-1 and upregulating ZNRF1 were sufficient to improve EDR of diabetic aortas, while overexpression of Cav-1 and downregulation of ZNRF1 abolished the effects of NCEH1 on endothelial function in diabetes. Thus, NCEH1 preserves endothelial function through increasing NO bioavailability secondary to the disruption of the Cav-1/eNOS complex in the endothelium of diabetic mice, depending on ZNRF1-induced ubiquitination of Cav-1. CONCLUSIONS: NCEH1 may be a promising candidate for the prevention and treatment of vascular complications of diabetes.

Astrocytes in chronic pain and itch.

Astrocytes are critical for maintaining the homeostasis of the CNS. Increasing evidence suggests that a number of neurological and neuropsychiatric disorders, including chronic pain, may result from astrocyte 'gliopathy'. Indeed, in recent years there has been substantial progress in our understanding of how astrocytes can regulate nociceptive synaptic transmission via neuronal-glial and glial-glial cell interactions, as well as the involvement of spinal and supraspinal astrocytes in the modulation of pain signalling and the maintenance of neuropathic pain. A role of astrocytes in the pathogenesis of chronic itch is also emerging. These developments suggest that targeting the specific pathways that are responsible for astrogliopathy may represent a novel approach to develop therapies for chronic pain and chronic itch.

Microglial STING activation alleviates nerve injury-induced neuropathic pain in male but not female mice.

Microglia, resident immune cells in the central nervous system, play a role in neuroinflammation and the development of neuropathic pain. We found that the stimulator of interferon genes (STING) is predominantly expressed in spinal microglia and upregulated after peripheral nerve injury. However, mechanical allodynia, as a marker of neuropathic pain following peripheral nerve injury, did not require microglial STING expression. In contrast, STING activation by specific agonists (ADU-S100, 35 nmol) significantly alleviated neuropathic pain in male mice, but not female mice. STING activation in female mice leads to increase in proinflammatory cytokines that may counteract the analgesic effect of ADU-S100. Microglial STING expression and type I interferon-ß (IFN-ß) signaling were required for the analgesic effects of STING agonists in male mice. Mechanistically, downstream activation of TANK-binding kinase 1 (TBK1) and the production of IFN-ß, may partly account for the analgesic effect observed. These findings suggest that STING activation in spinal microglia could be a potential therapeutic intervention for neuropathic pain, particularly in males.

Risk factors for short-term prognosis of end-stage liver disease complicated by invasive pulmonary aspergillosis.

BACKGROUND AND AIM: Patients with end-stage liver disease (ESLD) are susceptible to invasive pulmonary aspergillosis (IPA). This study aimed to investigate the risk factors affecting the occurrence and short-term prognosis of ESLD complicated by IPA. METHODS: This retrospective case-control study included 110 patients with ESLD. Of them, 27 ESLD-IPA received antifungal therapy with amphotericin B (AmB); 27 AmB-free-treated ESLD-IPA patients were enrolled through 1:1 propensity score matching. Fifty-six ESLD patients with other comorbid pulmonary infections were enrolled as controls. The basic features of groups were compared, while the possible risk factors affecting the occurrence and short-term outcomes of IPA were analyzed. RESULTS: Data analysis revealed invasive procedures, glucocorticoid exposure, and broad-spectrum antibiotic use were independent risk factors for IPA. The 54 patients with ESLD-IPA exhibited an overall treatment effectiveness and 28-d mortality rate of 50.00% and 20.37%, respectively, in whom patients treated with AmB-containing showed higher treatment efficacy than patients treated with AmB-free antifungal regimens (66.7% vs. 33.3%, respectively, χ2 = 6.000, P = 0.014). Multivariate logistic regression analysis revealed that the treatment regimen was the only predictor affecting patient outcomes, with AmB-containing regimens were 4.893 times more effective than AmB-free regimens (95% CI, 1.367-17.515; P = 0.015). The only independent predictors affecting the 28-d mortality rate were neutrophil-to-lymphocyte ratio and IPA diagnosis (OR = 1.140 and 10.037, P = 0.046 and 0.025, respectively). CONCLUSIONS: Glucocorticoid exposure, invasive procedures, and broad-spectrum antibiotic exposure increased the risk of IPA in ESLD patients. AmB alone or combined with other antifungals may serve as an economical, safe, and effective treatment option for ESLD-IPA.

Hydrogen sulfide in health and diseases: cross talk with noncoding RNAs.

Hydrogen sulfide (H2S) is previously described as a potentially lethal toxic gas. However, this gasotransmitter is also endogenously generated by the actions of cystathionine-ß-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST) in mammalian systems, thus belonging to the family of gasotransmitters after nitric oxide (NO) and carbon monoxide (CO). The physiological or pathological significance of H2S has been extensively expanded for decades. Growing evidence has revealed that H2S exerts cytoprotective functions in the cardiovascular, nervous, and gastrointestinal systems by modulating numerous signaling pathways. With the continuous advancement of microarray and next-generation sequencing technologies, noncoding RNAs (ncRNAs) have gained recognition as key players in human health and diseases due to their considerable potential as predictive biomarkers and therapeutic targets. Coincidentally, H2S and ncRNAs are not independent regulators but interact with each other during the development and progression of human diseases. Specifically, ncRNAs might serve as downstream mediators of H2S or act on H2S-generating enzymes to govern endogenous H2S production. The purpose of this review is to summarize the interactive regulatory roles of H2S and ncRNAs in the initiation and development of various diseases and explore their potential health and therapeutic benefits. This review will also highlight the importance of cross talk between H2S and ncRNAs in disease therapy.

Intrathecal administration of conditioned serum from different species resolves Chemotherapy-Induced neuropathic pain in mice via secretory exosomes.

Chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of chemotherapy for cancer, and has limited effective treatment options. Autologous conditioned serum (ACS) is an effective biologic therapy used by intra-articular injection for patients with osteoarthritis. However, ACS has not been systematically tested in the treatment of peripheral neuropathies such as CIPN. It has been generally assumed that the analgesic effect of this biologic therapy results from augmented concentrations of anti-inflammatory cytokines and growth factors. Here we report that a single intrathecal injection of human conditioned serum (hCS) produced long-lasting inhibition of paclitaxel chemotherapy-induced neuropathic pain (mechanical allodynia) in mice, without causing motor impairment. Strikingly, the analgesic effect of hCS in our experiments was maintained even 8 weeks after the treatment, compared with non-conditioned human serum (hNCS). Furthermore, the hCS transfer-induced pain relief in mice was fully recapitulated by rat or mouse CS transfer to mice of both sexes, indicating cross-species and cross-sex effectiveness. Mechanistically, CS treatment blocked the chemotherapy-induced glial reaction in the spinal cord and improved nerve conduction. Compared to NCS, CS contained significantly higher concentrations of anti-inflammatory and pro-resolving mediators, including IL-1Ra, TIMP-1, TGF-ß1, and resolvins D1/D2. Intrathecal injection of anti-TGF-ß1 and anti-Il-1Ra antibody transiently reversed the analgesic action of CS. Nanoparticle tracking analysis revealed that rat conditioned serum contained a significantly greater number of exosomes than NCS. Importantly, the removal of exosomes by high-speed centrifugation largely diminished the CS-produced pain relief, suggesting a critical involvement of small vesicles (exosomes) in the beneficial effects of CS. Together, our findings demonstrate that intrathecal CS produces a remarkable resolution of neuropathic pain mediated through a combination of small vesicles/exosomes and neuroimmune/neuroglial modulation.

Astrocytic neuroligins control astrocyte morphogenesis and synaptogenesis.

Astrocytes are complex glial cells with numerous fine cellular processes that infiltrate the neuropil and interact with synapses. The mechanisms that control the establishment of astrocyte morphology are unknown, and it is unclear whether impairing astrocytic infiltration of the neuropil alters synaptic connectivity. Here we show that astrocyte morphogenesis in the mouse cortex depends on direct contact with neuronal processes and occurs in parallel with the growth and activity of synaptic circuits. The neuroligin family cell adhesion proteins NL1, NL2, and NL3, which are expressed by cortical astrocytes, control astrocyte morphogenesis through interactions with neuronal neurexins. Furthermore, in the absence of astrocytic NL2, the formation and function of cortical excitatory synapses are diminished, whereas inhibitory synaptic function is enhanced. Our findings highlight a previously undescribed mechanism of action for neuroligins and link astrocyte morphogenesis to synaptogenesis. Because neuroligin mutations have been implicated in various neurological disorders, these findings also point towards an astrocyte-based mechanism of neural pathology.

Inflammatory changes in the plasma and cerebrospinal fluid of patients with persistent pain and postpartum depression after elective Cesarean delivery: an exploratory prospective cohort study.

PURPOSE: Severe acute pain after Cesarean delivery increases the risk of developing persistent pain (~20% incidence) and postpartum depression (PPD) (~15% incidence). Both conditions contribute to maternal morbidity and mortality, yet early risk stratification remains challenging. Neuroinflammation has emerged as a key mechanism of persistent pain and depression in nonobstetric populations. Nevertheless, most studies focus on plasma cytokines, and the relationship between plasma and cerebrospinal fluid (CSF) cytokine levels is unclear. Our primary aim was to compare inflammatory marker levels between patients who developed the composite outcome of persistent pain and/or PPD vs those who did not. METHODS: We recruited term patients with singleton pregnancies undergoing elective Cesarean delivery under neuraxial anesthesia into an exploratory prospective cohort study. We collected baseline demographic, obstetric, and Edinburgh Postnatal Depression Scale information, and performed quantitative sensory tests. Plasma was collected preoperatively and 48 hr postoperatively. In the operating room, 10 mL of CSF was collected, followed by a standardized anesthetic. Intra- and postoperative management were according to standard practice. We obtained Edinburgh Postnatal Depression Scale and pain scores at six weeks and three months after delivery. The primary outcome was persistent pain and/or PPD at three months. We analyzed the difference in inflammatory marker levels between the groups (primary aim) using two-sided Mann-Whitney tests. RESULTS: Eighty participants were enrolled, and 63 patients completed the study; 23 (37%) experienced the primary outcome at three months. Preoperative plasma transforming growth factor beta 1 (TGF-ß1) concentration was higher in patients who developed the primary outcome compared with those who did not (median [interquartile range (IQR)], 2,879 [2,241-5,494] vs 2,292 [1,676-2,960] pg·mL-1; P = 0.04), while CSF IL-1ß concentration was higher in patients who developed the primary outcome than in those who did not (median [IQR], 0.36 [0.29-0.39] vs 0.30 [0.25-0.35] pg·mL-1; P = 0.03). CONCLUSIONS: We observed differential levels of plasma and CSF inflammatory biomarkers in patients who developed persistent pain and PPD compared with those who did not. We showed the feasibility of collecting plasma and CSF samples at Cesarean delivery, which may prove useful for future risk-stratification. STUDY REGISTRATION: ClinicalTrials.gov (NCT04271072); registered 17 February 2020.

RéSUMé: OBJECTIF: La douleur aiguë sévère après un accouchement par césarienne augmente le risque de douleur persistante (~20 % d'incidence) et de dépression post-partum (DPP) (~15 % d'incidence). Ces deux conditions contribuent à la morbidité et à la mortalité maternelles, mais la stratification précoce des risques demeure difficile. La neuroinflammation est apparue comme un mécanisme clé de la douleur persistante et de la dépression dans les populations non obstétricales. Néanmoins, la plupart des études se concentrent sur les cytokines plasmatiques, et la relation entre les taux de cytokines plasmatiques et de liquide céphalorachidien (LCR) n'est pas claire. Notre objectif principal était de comparer les taux de marqueurs inflammatoires entre les patient·es qui ont eu un résultat composite de douleur persistante et/ou de DPP vs les personnes qui n'en ont pas eu. MéTHODE: Nous avons recruté des patient·es à terme avec des grossesses uniques bénéficiant d'une césarienne programmée sous anesthésie neuraxiale dans une étude de cohorte prospective exploratoire. Nous avons recueilli des informations démographiques de base, obstétricales et tirées de l'Échelle de dépression postnatale d'Édimbourg, et effectué des tests sensoriels quantitatifs. Le plasma a été prélevé avant l'opération et 48 heures après l'opération. En salle d'opération, 10 mL de LCR ont été recueillis, suivis d'un anesthésie standardisée. La prise en charge per- et postopératoire était conforme à la pratique courante. Nous avons obtenu les scores sur l'Échelle de dépression postnatale d'Édimbourg et les scores de douleur six semaines et trois mois après l'accouchement. Le critère d'évaluation principal était la douleur persistante et/ou la DPP à trois mois. Nous avons analysé la différence dans les niveaux de marqueurs inflammatoires entre les groupes (objectif principal) en utilisant des tests bilatéraux de Mann-Whitney. RéSULTATS: Quatre-vingts personnes ont été recrutées et 63 patient·es ont terminé l'étude; 23 (37 %) ont rapporté le critère d'évaluation principal à trois mois. Le facteur TGF-ß1 (transforming growth factor beta 1) plasmatique préopératoire était plus élevé chez les patient·es qui ont manifesté le critère d'évaluation principal par rapport aux personnes qui ne l'ont pas manifesté (médiane [écart interquartile (ÉIQ)], 2879 [2241-5494] vs 2292 [1676­2960] pg·mL−1; P = 0,04), tandis que le IL-1ß dans le LCR était plus élevé chez les patient·es qui ont manifesté le critère d'évaluation principal que chez les personnes qui ne l'ont pas manifesté (médiane [ÉIQ], 0,36 [0,29-0,39] vs 0,30 [0,25­0,35] pg·mL−1; P = 0,03). CONCLUSION: Nous avons observé des taux différentiels de biomarqueurs inflammatoires plasmatiques et de LCR chez les patient·es qui ont manifesté une douleur persistante et une DPP par rapport aux personnes qui n'en ont pas manifesté. Nous avons montré la faisabilité de la collecte d'échantillons de plasma et de LCR lors de l'accouchement par césarienne, ce qui pourrait s'avérer utile pour la stratification future des risques. ENREGISTREMENT DE L'éTUDE: clinicaltrials.gov (NCT04271072); enregistrée le 17 février 2020.

[Effect of Ropivacaine Combined with Dexmedetomidine for Serratus Anterior Plane Block Plus Patient-Controlled Intravenous Analgesia on Postoperative Recovery Quality of Patients Undergoing Thoracoscopic Radical Resection of Lung Cancer].

Objective: To study the postoperative analgesic effect of ropivacaine combined with dexmedetomidine for serratus anterior plane block (SAPB) under ultrasound visualization plus patient-controlled intravenous analgesia (PCIA) in patients undergoing thoracoscopic radical resection of lung cancer. Methods: A total of 129 patients undergoing elective thoracoscopic surgery were enrolled. The patients were randomly assigned to three groups ( n=43 in each group), a normal saline group (control group), a ropivacaine mesylate group (Group R) and a ropivacaine mesylate combined with dexmetomidine hydrochloride group (Group RD). After operation, ultrasound-guided SAPB was performed and patients in the three groups received the injection of 0 mL of 0.9% normal saline, 25 mL of 0.5% ropivacaine, and 25 mL of 0.5% ropivacaine+1 µg/kg dextrometomidine hydrochloride mixture, respectively. In addition, PCIA was used for all the patients. The button on the PCIA pump was pressed when the postoperative pain visual analogue score (VAS)≥4 on coughing, and rescue analgesic of sufentanil was given intravenously at 2.5 µg/bolus. The primary outcome was the VAS scores at rest and on coughing at 10 min (T 1), 6 h (T 2), 12 h (T 3), 24 h (T 4), and 48 h (T 5) after extubation. The secondary outcomes included hemodynamics, the quality of sleep for the first 3 nights after operation, number of times the button on the PCIA pump was pressed, intraoperative and postoperative opioid dosage, time of first postoperative rescue analgesic, duraion of intubation, length of stay at the hospital, adverse reactions, etc. Results: Compared with those of the control group, the VAS scores of the Group R and Group RD were significantly lower at 10 min, 6 h, and 12 h after extubation ( P<0.05). In comparison with Group R, the number of patients requiring rescue analgesia, the time of first postoperative rescue analgesic, the number of times the button on the PCIA pump was pressed, and the total dose of rescue sufentanil were all significantly lower ( P<0.05) in the Group RD. Patients in the Group RD had better sleep quality in the second and third nights after operation and lower incidence of nausea and vomiting ( P<0.05). Conclusion: 0.5% ropivacaine and 1 µg/kg dexmedetomidine SAPB combined with PCIA can significantly reduce postoperative pain and improve postoperative recovery quality in patients undergoing thoracoscopic radical resection of lung cancer.

Epithelia-Sensory Neuron Cross Talk Underlies Cholestatic Itch Induced by Lysophosphatidylcholine.

BACKGROUND & AIMS: Limited understanding of pruritus mechanisms in cholestatic liver diseases hinders development of antipruritic treatments. Previous studies implicated lysophosphatidic acid (LPA) as a potential mediator of cholestatic pruritus. METHODS: Pruritogenicity of lysophosphatidylcholine (LPC), LPA's precursor, was examined in naïve mice, cholestatic mice, and nonhuman primates. LPC's pruritogenicity involving keratinocyte TRPV4 was studied using genetic and pharmacologic approaches, cultured keratinocytes, ion channel physiology, and structural computational modeling. Activation of pruriceptor sensory neurons by microRNA-146a (miR-146a), secreted from keratinocytes, was identified by in vitro and ex vivo Ca2+ imaging assays. Sera from patients with primary biliary cholangitis were used for measuring the levels of LPC and miR-146a. RESULTS: LPC was robustly pruritic in mice. TRPV4 in skin keratinocytes was essential for LPC-induced itch and itch in mice with cholestasis. Three-dimensional structural modeling, site-directed mutagenesis, and channel function analysis suggested a TRPV4 C-terminal motif for LPC binding and channel activation. In keratinocytes, TRPV4 activation by LPC induced extracellular release of miR-146a, which activated TRPV1+ sensory neurons to cause itch. LPC and miR-146a levels were both elevated in sera of patients with primary biliary cholangitis with itch and correlated with itch intensity. Moreover, LPC and miR-146a were also increased in sera of cholestatic mice and elicited itch in nonhuman primates. CONCLUSIONS: We identified LPC as a novel cholestatic pruritogen that induces itch through epithelia-sensory neuron cross talk, whereby it directly activates skin keratinocyte TRPV4, which rapidly releases miR-146a to activate skin-innervating TRPV1+ pruriceptor sensory neurons. Our findings support the new concept of the skin, as a sensory organ, playing a critical role in cholestatic itch, beyond liver, peripheral sensory neurons, and central neural pathways supporting pruriception.

Central opioid receptors mediate morphine-induced itch and chronic itch via disinhibition.

Opioids such as morphine are mainstay treatments for clinical pain conditions. Itch is a common side effect of opioids, particularly as a result of epidural or intrathecal administration. Recent progress has advanced our understanding of itch circuits in the spinal cord. However, the mechanisms underlying opioid-induced itch are not fully understood, although an interaction between µ-opioid receptor (MOR) and gastrin-releasing peptide receptor (GRPR) in spinal GRPR-expressing neurons has been implicated. In this study we investigated the cellular mechanisms of intrathecal opioid-induced itch by conditional deletion of MOR-encoding Oprm1 in distinct populations of interneurons and sensory neurons. We found that intrathecal injection of the MOR agonists morphine or DAMGO elicited dose-dependent scratching as well as licking and biting, but this pruritus was totally abolished in mice with a specific Oprm1 deletion in Vgat+ neurons [Oprm1-Vgat (Slc32a1)]. Loss of MOR in somatostatin+ interneurons and TRPV1+ sensory neurons did not affect morphine-induced itch but impaired morphine-induced antinociception. In situ hybridization revealed Oprm1 expression in 30% of inhibitory and 20% of excitatory interneurons in the spinal dorsal horn. Whole-cell recordings from spinal cord slices showed that DAMGO induced outward currents in 9 of 19 Vgat+ interneurons examined. Morphine also inhibited action potentials in Vgat+ interneurons. Furthermore, morphine suppressed evoked inhibitory postsynaptic currents in postsynaptic Vgat- excitatory neurons, suggesting a mechanism of disinhibition by MOR agonists. Notably, morphine-elicited itch was suppressed by intrathecal administration of NPY and abolished by spinal ablation of GRPR+ neurons with intrathecal injection of bombesin-saporin, whereas intrathecal GRP-induced itch response remained intact in mice lacking Oprm1-Vgat. Intrathecal bombesin-saporin treatment reduced the number of GRPR+ neurons by 97% in the lumber spinal cord and 91% in the cervical spinal cord, without changing the number of Oprm1+ neurons. Additionally, chronic itch from DNFB-induced allergic contact dermatitis was decreased by Oprm1-Vgat deletion. Finally, naloxone, but not peripherally restricted naloxone methiodide, inhibited chronic itch in the DNFB model and the CTCL model, indicating a contribution of central MOR signalling to chronic itch. Our findings demonstrate that intrathecal morphine elicits itch via acting on MOR on spinal inhibitory interneurons, leading to disinhibition of the spinal itch circuit. Our data also provide mechanistic insights into the current treatment of chronic itch with opioid receptor antagonist such as naloxone.

Extracellular Vesicle-Mediated Vascular Cell Communications in Hypertension: Mechanism Insights and Therapeutic Potential of ncRNAs.

Hypertension, a chronic and progressive disease, is an outstanding public health issue that affects nearly 40% of the adults worldwide. The increasing prevalence of hypertension is one of the leading causes of cardiovascular morbidity and mortality. Despite of the available treatment medications, an increasing number of hypertensive individuals continues to have uncontrolled blood pressure. In the vasculature, endothelial cells, vascular smooth muscle cells (VSMCs), and adventitial fibroblasts play a fundamental role in vascular homeostasis. The aberrant interactions between vascular cells might lead to hypertension and vascular remodeling. Identification of the precise mechanisms of vascular remodeling may be highly required to develop effective therapeutic approaches for hypertension. Recently, extracellular vesicle-mediated transfer of proteins or noncoding RNAs (ncRNAs) between vascular cells holds promise for the treatment of hypertension. Especially, extracellular vesicle-packaging ncRNAs have gained enormous attention of basic and clinical scientists because of their tremendous potential to act as novel clinical biomarkers and therapeutic targets of hypertension. Here we will discuss the current findings focusing on the emerging roles of extracellular vesicle-carrying ncRNAs in the pathologies of hypertension and its associated vascular remodeling. Furthermore, we will highlight the potential of extracellular vesicles and ncRNAs as biomarkers and therapeutic targets for hypertension. The future research directions on the challenges and perspectives of extracellular vesicles and ncRNAs in hypertensive vascular remodeling are also proposed.

Neutrophil CD64 index for diagnosis of infectious disease in the pediatric ICU: a single-center prospective study.

BACKGROUND: Infection is a major cause of death in children, and it is particularly important to identify biological indicators of early infection. Previous studies showed that the neutrophil CD64 (nCD64) index may be a useful biomarker for infection. The purpose of this study was to investigate use of the nCD64 index to identify infection in children from a pediatric ICU (PICU) in China. METHODS: This prospective observational study enrolled 201 children who were admitted to our PICU and were divided into an infection group and a non-infection group. In each patient, C-reactive protein (CRP), nCD64 index, procalcitonin (PCT), and white blood cell count were measured during the first 24 h after admission. Receiver operating characteristic (ROC) analyses were used to determine the sensitivity, specificity, and diagnostic value of the nCD64 index for infection. RESULTS: Among all 201 children, the infection group had greater levels of CRP, nCD64 index, and PCT (all p < 0.05). ROC analysis indicated the nCD64 index had a sensitivity of 68.8%, specificity of 90.7%, accuracy of 80.5%, and an optimal cut-off value of 0.14, which had better diagnostic value than CRP or PCT. For children with postoperative fever, the nCD64 index also distinguished systemic inflammatory response syndrome (SIRS) from infection with accuracy of 79%. CONCLUSIONS: The nCD64 index is a useful biomarker for the diagnosis of early infection in children admitted to the PICU.

Functional selection of protease inhibitory antibodies.

Critical for diverse biological processes, proteases represent one of the largest families of pharmaceutical targets. To inhibit pathogenic proteases with desired selectivity, monoclonal antibodies (mAbs) hold great promise as research tools and therapeutic agents. However, identification of mAbs with inhibitory functions is challenging because current antibody discovery methods rely on binding rather than inhibition. This study developed a highly efficient selection method for protease inhibitory mAbs by coexpressing 3 recombinant proteins in the periplasmic space of Escherichia coli-an antibody clone, a protease of interest, and a ß-lactamase modified by insertion of a protease cleavable peptide sequence. During functional selection, inhibitory antibodies prevent the protease from cleaving the modified ß-lactamase, thereby allowing the cell to survive in the presence of ampicillin. Using this method to select from synthetic human antibody libraries, we isolated panels of mAbs inhibiting 5 targets of 4 main protease classes: matrix metalloproteinases (MMP-14, a predominant target in metastasis; MMP-9, in neuropathic pain), ß-secretase 1 (BACE-1, an aspartic protease in Alzheimer's disease), cathepsin B (a cysteine protease in cancer), and Alp2 (a serine protease in aspergillosis). Notably, 37 of 41 identified binders were inhibitory. Isolated mAb inhibitors exhibited nanomolar potency, exclusive selectivity, excellent proteolytic stability, and desired biological functions. Particularly, anti-Alp2 Fab A4A1 had a binding affinity of 11 nM and inhibition potency of 14 nM, anti-BACE1 IgG B2B2 reduced amyloid beta (Aß40) production by 80% in cellular assays, and IgG L13 inhibited MMP-9 but not MMP-2/-12/-14 and significantly relieved neuropathic pain development in mice.