Rhythmic cilia changes support SCN neuron coherence in circadian clock.

The suprachiasmatic nucleus (SCN) drives circadian clock coherence through intercellular coupling, which is resistant to environmental perturbations. We report that primary cilia are required for intercellular coupling among SCN neurons to maintain the robustness of the internal clock in mice. Cilia in neuromedin S-producing (NMS) neurons exhibit pronounced circadian rhythmicity in abundance and length. Genetic ablation of ciliogenesis in NMS neurons enabled a rapid phase shift of the internal clock under jet-lag conditions. The circadian rhythms of individual neurons in cilia-deficient SCN slices lost their coherence after external perturbations. Rhythmic cilia changes drive oscillations of Sonic Hedgehog (Shh) signaling and clock gene expression. Inactivation of Shh signaling in NMS neurons phenocopied the effects of cilia ablation. Thus, cilia-Shh signaling in the SCN aids intercellular coupling.

Global trend and future landscape of intestinal microcirculation research from 2000 to 2021: A scientometric study.

BACKGROUND: The intestinal microcirculation functions in food absorption and metabolic substance exchanges. Accumulating evidence indicates that intestinal microcirculatory dysfunction is a significant source of multiple gastrointestinal diseases. To date, there has not been a scientometric analysis of intestinal microcirculatory research. AIM: To investigate the current status, development trends, and frontiers of intestinal microcirculatory research based on bibliometric analysis. METHODS: VOSviewer and CiteSpace 6.1.R2 were used to identify the overall characteristics and knowledge map of intestinal microcirculatory research based on the core literature published from 2000 to 2021 in the Web of Science database. The characteristics of each article, country of origin, institution, journal, cocitations, and other information were analyzed and visualized. RESULTS: There were 1364 publications enrolled in the bibliometric analysis, exhibiting an upward trend from 2000 to 2021 with increased participation worldwide. The United States and Dalhousie University took the lead among countries and institutions, respectively. Shock was the most prolific journal, and Nature Reviews Microbiology Clinical had the most citations. The topical hotspots and frontiers in intestinal microcirculatory research were centered on the pathological processes of functional impairment of intestinal microvessels, diverse intestinal illnesses, and clinical treatment. CONCLUSION: Our study highlights insights into trends of the published research on the intestinal microcirculation and offers serviceable guidance to researchers by summarizing the prolific areas in intestinal disease research to date.

Glioblastoma stem cell-specific histamine secretion drives pro-angiogenic tumor microenvironment remodeling.

The communication between glioblastoma stem cells (GSCs) and the surrounding microenvironment is a prominent feature accounting for the aggressive biology of glioblastoma multiforme (GBM). However, the mechanisms by which GSCs proactively drive interactions with microenvironment is not well understood. In this study, we interrogated metabolites that are preferentially secreted from GSCs and found that GSCs produce and secrete histamine to shape a pro-angiogenic tumor microenvironment. This histamine-producing ability is attributed to H3K4me3 modification-activated histidine decarboxylase (HDC) transcription via MYC. Notably, HDC is highly expressed in GBM, which is associated with poor survival of these patients. GSC-secreted histamine activates endothelial cells by triggering a histamine H1 receptor (H1R)-Ca2+-NF-κB axis, thereby promoting angiogenesis and GBM progression. Importantly, pharmacological blockage of H1R using antihistamines impedes the growth of GBM xenografts in mice. Our findings establish that GSC-specific metabolite secretion remodels the tumor microenvironment and highlight histamine targeting as a potential strategy for GBM therapy.

Role of insulin in pancreatic microcirculatory oxygen profile and bioenergetics.

BACKGROUND: The pancreatic islet microcirculation adapts its metabolism to cope with limited oxygen availability and nutrient delivery. In diabetes, the balance between oxygen delivery and consumption is impaired. Insulin has been proven to exert complex actions promoting the maintenance of homeostasis of the pancreas under glucotoxicity. AIM: To test the hypothesis that insulin administration can improve the integrated pancreatic microcirculatory oxygen profile and bioenergetics. METHODS: The pancreatic microcirculatory partial oxygen pressure (PO2), relative hemoglobin (rHb) and hemoglobin oxygen saturation (SO2) were evaluated in nondiabetic, type 1 diabetes mellitus (T1DM), and insulin-treated mice. A three-dimensional framework was generated to visualize the microcirculatory oxygen profile. Ultrastructural changes in the microvasculature were examined using transmission electron microscopy. An Extracellular Flux Analyzer was used to detect the real-time changes in bioenergetics by measuring the oxygen consumption rate and extracellular acidification rate in islet microvascular endothelial cells (IMECs). RESULTS: Significantly lower PO2, rHb, and SO2 values were observed in T1DM mice than in nondiabetic controls. Insulin administration ameliorated the streptozotocin-induced decreases in these microcirculatory oxygen parameters and improved the mitochondrial ultrastructural abnormalities in IMECs. Bioenergetic profiling revealed that the IMECs did not have spare respiratory capacity. Insulin-treated IMECs exhibited significantly greater basal respiration than glucotoxicity-exposed IMECs (P < 0.05). An energy map revealed increased energetic metabolism in insulin-treated IMECs, with significantly increased ATP production, non-mitochondrial respiration, and oxidative metabolism (all P < 0.05). Significant negative correlations were revealed between microcirculatory SO2 and bioenergetic parameters. CONCLUSION: Glucotoxicity deteriorates the integrated pancreatic microcirculatory oxygen profile and bioenergetics, but this deterioration can be reversed by insulin administration.

The stress granule protein G3BP1 promotes pre-condensation of cGAS to allow rapid responses to DNA.

Cyclic GMP-AMP synthase (cGAS) functions as a key sensor for microbial invasion and cellular damage by detecting emerging cytosolic DNA. Here, we report that GTPase-activating protein-(SH3 domain)-binding protein 1 (G3BP1) primes cGAS for its prompt activation by engaging cGAS in a primary liquid-phase condensation state. Using high-resolution microscopy, we show that in resting cells, cGAS exhibits particle-like morphological characteristics, which are markedly weakened when G3BP1 is deleted. Upon DNA challenge, the pre-condensed cGAS undergoes liquid-liquid phase separation (LLPS) more efficiently. Importantly, G3BP1 deficiency or its inhibition dramatically diminishes DNA-induced LLPS and the subsequent activation of cGAS. Interestingly, RNA, previously reported to form condensates with cGAS, does not activate cGAS. Accordingly, we find that DNA - but not RNA - treatment leads to the dissociation of G3BP1 from cGAS. Taken together, our study shows that the primary condensation state of cGAS is critical for its rapid response to DNA.

LUBAC regulates ciliogenesis by promoting CP110 removal from the mother centriole.

Primary cilia transduce diverse signals in embryonic development and adult tissues. Defective ciliogenesis results in a series of human disorders collectively known as ciliopathies. The CP110-CEP97 complex removal from the mother centriole is an early critical step for ciliogenesis, but the underlying mechanism for this step remains largely obscure. Here, we reveal that the linear ubiquitin chain assembly complex (LUBAC) plays an essential role in ciliogenesis by targeting the CP110-CEP97 complex. LUBAC specifically generates linear ubiquitin chains on CP110, which is required for CP110 removal from the mother centriole in ciliogenesis. We further identify that a pre-mRNA splicing factor, PRPF8, at the distal end of the mother centriole acts as the receptor of the linear ubiquitin chains to facilitate CP110 removal at the initial stage of ciliogenesis. Thus, our study reveals a direct mechanism of regulating CP110 removal in ciliogenesis and implicates the E3 ligase LUBAC as a potential therapy target of cilia-associated diseases, including ciliopathies and cancers.

An adolescent rat model of vincristine-induced peripheral neuropathy.

Childhood acute lymphoblastic leukemia (ALL) is a significant clinical problem that can be effectively treated with vincristine, a vinca alkaloid-based chemotherapeutic agent. However, nearly all children receiving vincristine treatment develop vincristine-induced peripheral neuropathy (VIPN). The impact of adolescent vincristine treatment across the lifespan remains poorly understood. We, consequently, developed an adolescent rodent model of VIPN which can be utilized to study possible long term consequences of vincristine treatment in the developing rat. We also evaluated the therapeutic efficacy of voluntary exercise and potential impact of obesity as a genetic risk factor in this model on the development and maintenance of VIPN. Out of all the dosing regimens we evaluated, the most potent VIPN was produced by fifteen consecutive daily intraperitoneal (i.p.) vincristine injections at 100 µg/kg/day, throughout the critical period of adolescence from postnatal day 35 to 49. With this treatment, vincristine-treated animals developed hypersensitivity to mechanical and cold stimulation of the plantar hind paw surface, which outlasted the period of vincristine treatment and resolved within two weeks following the cessation of vincristine injection. By contrast, impairment in grip strength gain was delayed by vincristine treatment, emerging shortly following the termination of vincristine dosing, and persisted into early adulthood without diminishing. Interestingly, voluntary wheel running exercise prevented the development of vincristine-induced hypersensitivities to mechanical and cold stimulation. However, Zucker fa/fa obese animals did not exhibit higher risk of developing VIPN compared to lean rats. Our studies identify sensory and motor impairments produced by vincristine in adolescent animals and support the therapeutic efficacy of voluntary exercise for suppressing VIPN in developing rats.

G3BP1 Inhibition Alleviates Intracellular Nucleic Acid-Induced Autoimmune Responses.

The detection of intracellular nucleic acids is a fundamental mechanism of host defense against infections. The dysregulated nucleic acid sensing, however, is a major cause for a number of autoimmune diseases. In this study, we report that GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is critical for both intracellular DNA- and RNA-induced immune responses. We found that in both human and mouse cells, the deletion of G3BP1 led to the dampened cGAS activation by DNA and the insufficient binding of RNA by RIG-I. We further found that resveratrol (RSVL), a natural compound found in grape skin, suppressed both intracellular DNA- and RNA-induced type I IFN production through inhibiting G3BP1. Importantly, using experimental mouse models for Aicardi-Goutières syndrome, an autoimmune disorder found in humans, we demonstrated that RSVL effectively alleviated intracellular nucleic acid-stimulated autoimmune responses. Thus, our study demonstrated a broader role of G3BP1 in sensing different kinds of intracellular nucleic acids and presented RSVL as a potential treatment for autoimmune conditions caused by dysregulated nucleic acid sensing.

Hsa Circ 001839 Promoted Inflammation in Renal Ischemia-Reperfusion Injury Through NLRP3 by miR-432-3p.

BACKGROUND: In recent years, increasing discovery of the extremely important regulatory effects of circular RNAs on biological development, angiogenesis, tumor genesis, and development, as well as stem cell proliferation and differentiation has provided new opportunities for investigating regulation mechanism in angiogenesis. OBJECTIVES: This study explored the expression of circ 001839 in renal ischemia-reperfusion injury (RI-RI) rats and whether its upstream microRNA-432-3p (miR-432-3p) affects inflammation in both RI-RI rats and NRK52E cells. METHODS: Rat model of RI-RI was made, and circ 001839 was identified by the gene-chip analysis in RI-RI rats. Expression of circ 001839 and miR-432-3p was measured by reverse transcription-quantitative polymerase chain reaction, protein expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, interferon (IFN)-γ, IL-6, and IL-18 in rat serum and cell supernatant was determined by ELISA, and the expression of NOD-like receptor 3 (NLRP3) and other gap-associated proteins in NRK52E cells was evaluated by Western blot analysis. Next, to verify the regulatory relationship between circ 001839 and miR-432-3p, 2 luciferase reporters were constructed. RESULTS: Circ 001839 expression of RI-RI rats and NRK52E cells was significantly upregulated, compared with the control group. Circ 001839 overexpression significantly increased inflammation through promoting TNF-α, IFN-γ, and IL-6 expression levels in NRK52E cells. Overexpression of miR-432-3p significantly promoted inflammation in NRK52E cells via induction of NLRP3. Moreover, miR-432-3p decreased the effects of circ 001839-induced inflammation in NRK52E cells. CONCLUSIONS: These findings suggested that circ 001839 promoted inflammation in RI-RI through NLRP3 by miR-432-3p.

Cannabidiol has a unique effect on global brain activity: a pharmacological, functional MRI study in awake mice.

BACKGROUND: The phytocannabinoid cannabidiol (CBD) exhibits anxiolytic activity and has been promoted as a potential treatment for post-traumatic stress disorders. How does CBD interact with the brain to alter behavior? We hypothesized that CBD would produce a dose-dependent reduction in brain activity and functional coupling in neural circuitry associated with fear and defense. METHODS: During the scanning session awake mice were given vehicle or CBD (3, 10, or 30 mg/kg I.P.) and imaged for 10 min post treatment. Mice were also treated with the 10 mg/kg dose of CBD and imaged 1 h later for resting state BOLD functional connectivity (rsFC). Imaging data were registered to a 3D MRI mouse atlas providing site-specific information on 138 different brain areas. Blood samples were collected for CBD measurements. RESULTS: CBD produced a dose-dependent polarization of activation along the rostral-caudal axis of the brain. The olfactory bulb and prefrontal cortex showed an increase in positive BOLD whereas the brainstem and cerebellum showed a decrease in BOLD signal. This negative BOLD affected many areas connected to the ascending reticular activating system (ARAS). The ARAS was decoupled to much of the brain but was hyperconnected to the olfactory system and prefrontal cortex. CONCLUSION: The CBD-induced decrease in ARAS activity is consistent with an emerging literature suggesting that CBD reduces autonomic arousal under conditions of emotional and physical stress.

GCG inhibits SARS-CoV-2 replication by disrupting the liquid phase condensation of its nucleocapsid protein.

Lack of detailed knowledge of SARS-CoV-2 infection has been hampering the development of treatments for coronavirus disease 2019 (COVID-19). Here, we report that RNA triggers the liquid-liquid phase separation (LLPS) of the SARS-CoV-2 nucleocapsid protein, N. By analyzing all 29 proteins of SARS-CoV-2, we find that only N is predicted as an LLPS protein. We further confirm the LLPS of N during SARS-CoV-2 infection. Among the 100,849 genome variants of SARS-CoV-2 in the GISAID database, we identify that ~37% (36,941) of the genomes contain a specific trio-nucleotide polymorphism (GGG-to-AAC) in the coding sequence of N, which leads to the amino acid substitutions, R203K/G204R. Interestingly, NR203K/G204R exhibits a higher propensity to undergo LLPS and a greater effect on IFN inhibition. By screening the chemicals known to interfere with N-RNA binding in other viruses, we find that (-)-gallocatechin gallate (GCG), a polyphenol from green tea, disrupts the LLPS of N and inhibits SARS-CoV-2 replication. Thus, our study reveals that targeting N-RNA condensation with GCG could be a potential treatment for COVID-19.

LPA signaling acts as a cell-extrinsic mechanism to initiate cilia disassembly and promote neurogenesis.

Dynamic assembly and disassembly of primary cilia controls embryonic development and tissue homeostasis. Dysregulation of ciliogenesis causes human developmental diseases termed ciliopathies. Cell-intrinsic regulatory mechanisms of cilia disassembly have been well-studied. The extracellular cues controlling cilia disassembly remain elusive, however. Here, we show that lysophosphatidic acid (LPA), a multifunctional bioactive phospholipid, acts as a physiological extracellular factor to initiate cilia disassembly and promote neurogenesis. Through systematic analysis of serum components, we identify a small molecular-LPA as the major driver of cilia disassembly. Genetic inactivation and pharmacological inhibition of LPA receptor 1 (LPAR1) abrogate cilia disassembly triggered by serum. The LPA-LPAR-G-protein pathway promotes the transcription and phosphorylation of cilia disassembly factors-Aurora A, through activating the transcription coactivators YAP/TAZ and calcium/CaM pathway, respectively. Deletion of Lpar1 in mice causes abnormally elongated cilia and decreased proliferation in neural progenitor cells, thereby resulting in defective neurogenesis. Collectively, our findings establish LPA as a physiological initiator of cilia disassembly and suggest targeting the metabolism of LPA and the LPA pathway as potential therapies for diseases with dysfunctional ciliogenesis.

[Diagnostic Application of Invasive Cardiopulmonary Exercise Test in Patients with Unexplained Dyspnea].

OBJECTIVE: To explore the clinical diagnostic application of invasive cardiopulmonary exercise test (iCPET) in patients with unexplained dyspnea. METHODS: A retrospective analysis was conducted, covering patients with a chief complaint of exertional dyspnea between May 5, 2017 and October 1, 2020. Right cardiac catheterization examination was performed on patients whose cause had not been identified through routine examination, and further iCPET was performed on patients if no clear etiology was identified through right cardiac catheterization. According to the results and the diagnostic criteria of iCPET, patients showing no obvious abnormalities in the right cardiac catheterization examination were divided into four subgroups: exercise-induced pulmonary arterial hypertension (eiPAH), exercise-induced heart failure with preserved ejection fraction (eiHFpEF), preload failure, and oxidative myopathy. By comparing the lab test, echocardiography, right heart catheter and iCPET peak exercise data of the subgroups, the disease distribution and exercise hemodynamic characteristics of patients with unexplained dyspnea examined by iCPET were described. RESULTS: Of the 1 046 patients with exertional dyspnea, 771 were diagnosed with routine examination, while among the remaining 275 patients, 131 (47.6%) were diagnosed with right cardiac catheterization and 144 (52.4%) showed no clear etiology after routine examination and right cardiac catheterization. Of these 144 patients, 49 (34.0%) received iCPET with a median exercise time of 375 s. A total of 47 patients completed the examination, with a male-to-female ratio of 0.27∶1 and an average age of (47.9±14.4) years old. Among the 47 patients, 76.6% (36/47) aged between 20 and 59 and 78.7% (36/47) lived in urban areas. The preload failure group ( n=27) showed low right atrium pressure at peak exercise intensity. The eiHFpEF group ( n=9) showed high wedge pressure of pulmonary capillaries at peak of exercise intensity. The eiPAH group ( n=8) showed high average pulmonary artery pressure at peak exercise intensity. The oxidative myopathy group ( n=3) was characterized by impairment of tissue uptake and/or utilization of oxygen during exercise. According to the comparison among the three subgroups of the preload failure, eiHFpEF and eiPAH, the eiPAH group had the highest blood K + level in routine examination, while the preload failure group had the lowest blood K + level ( P=0.014). The iCPET of the three subgroups showed statistically significant ( P=0.001) difference in right atrial pressure increase during exercise. Among the three, the eiHFpEF group had the highest increase and the preload failure group had the lowest increase. Conclusion 　In unexplained dyspnea patients showing no abnormal results in right cardiac catheterization examination, the main cause was preload failure, which manifested as low right atrial pressure at peak exercise intensity. The study showed that iCPET was of important value for dyspnea cases when the cause of the condition was not revealed with right cardiac catheterization.

CEP55 promotes cilia disassembly through stabilizing Aurora A kinase.

Primary cilia protrude from the cell surface and have diverse roles during development and disease, which depends on the precise timing and control of cilia assembly and disassembly. Inactivation of assembly often causes cilia defects and underlies ciliopathy, while diseases caused by dysfunction in disassembly remain largely unknown. Here, we demonstrate that CEP55 functions as a cilia disassembly regulator to participate in ciliopathy. Cep55-/- mice display clinical manifestations of Meckel-Gruber syndrome, including perinatal death, polycystic kidneys, and abnormalities in the CNS. Interestingly, Cep55-/- mice exhibit an abnormal elongation of cilia on these tissues. Mechanistically, CEP55 promotes cilia disassembly by interacting with and stabilizing Aurora A kinase, which is achieved through facilitating the chaperonin CCT complex to Aurora A. In addition, CEP55 mutation in Meckel-Gruber syndrome causes the failure of cilia disassembly. Thus, our study establishes a cilia disassembly role for CEP55 in vivo, coupling defects in cilia disassembly to ciliopathy and further suggesting that proper cilia dynamics are critical for mammalian development.

Naturally-derived diterpenoid sphaeropsidin C as an activator of Nrf2/ARE pathway and its potential capability of relieving intracellular oxidative stress in human lung epithelial cells.

Oxidative stress is closely associated to the onset and progression of many human diseases. Activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway using naturally-derived molecules is an efficient strategy for alleviating the intracellular oxidative insults, and thus blocking the pathogenesis of oxidative stress-induced diseases. In the present study, a naturally-derived isopimarane-type diterpenoid sphaeropsidin C (SC) was identified to be an activator of Nrf2/ARE signaling pathway. Our data indicated that SC was able to stimulate Nrf2-mediated defensive system through promoting Nrf2 translocation, inhibiting Nrf2 ubiquitination, and enhancing Nrf2 stability in normal human lung epithelial Beas-2B cells. Furthermore, SC-induced Nrf2 activation required the involvement of protein kinases, exemplified by protein kinase C (PKC), protein kinase R-like endoplasmic reticulum kinase (PERK), and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K). It alleviated sodium arsenite [As(III)]-induced intracellular oxidative stress in an Nrf2-dependent manner. These results suggested that SC displayed potential application for the prevention and therapy against oxidative stress-induced diseases. Moreover, isopimarane-type diterpenoid represents a promising skeleton for developing Nrf2 activators.

CYP3A4 and microRNA-122 are involved in the apoptosis of HepG2 cells induced by ILs 1-decyl-3-methylimidazolium bromide.

Ionic liquids (ILs) as green alternatives for volatile organic solvents are increasingly used in commercial applications. It is necessary to explore the cytotoxic mechanism of ILs to reduce the risk to human health. For this purpose, cell viability, apoptosis, cytochrome P450 3A4 (CYP3A4), glucose transporter type 2 (GLUT2), and microRNA-122 (miR-122) gene expression in HepG2 cells was evaluated after IL exposure. The results showed that ILs reduced the viability of HepG2 cells through apoptotic cell death. Moreover, ILs markedly upregulated the transcription and protein levels of CYP3A4, but did not affect the expression of GLUT2 in either messenger RNA level or protein level. Finally, ILs increased the expression of miR-122 and inhibition of miR-122 with miR-122 inhibitor blocked ILs-induced apoptosis in HepG2 cells. This finding may contribute to an increased understanding of the in vitro molecular toxicity mechanism of ILs to further understand IL-related human health risks.

Rab7 regulates primary cilia disassembly through cilia excision.

The primary cilium is a sensory organelle that protrudes from the cell surface. Primary cilia undergo dynamic transitions between assembly and disassembly to exert their function in cell signaling. In this study, we identify the small GTPase Rab7 as a novel regulator of cilia disassembly. Depletion of Rab7 potently induced spontaneous ciliogenesis in proliferating cells and promoted cilia elongation during quiescence. Moreover, Rab7 performs an essential role in cilia disassembly; knockdown of Rab7 blocked serum-induced ciliary resorption, and active Rab7 was required for this process. Further, we demonstrate that Rab7 depletion significantly suppresses cilia tip excision, referred to as cilia ectocytosis, which has been identified as required for cilia disassembly. Mechanically, the failure of F-actin polymerization at the site of excision of cilia tips caused suppression of cilia ectocytosis on Rab7 depletion. Overall, our results suggest a novel function for Rab7 in regulating cilia ectocytosis and cilia disassembly via control of intraciliary F-actin polymerization.

MAVS O-GlcNAcylation Is Essential for Host Antiviral Immunity against Lethal RNA Viruses.

It is known that lethal viruses profoundly manipulate host metabolism, but how the metabolism alternation affects the immediate host antiviral immunity remains elusive. Here, we report that the O-GlcNAcylation of mitochondrial antiviral-signaling protein (MAVS), a key mediator of interferon signaling, is a critical regulation to activate the host innate immunity against RNA viruses. We show that O-GlcNAcylation depletion in myeloid cells renders the host more susceptible to virus infection both in vitro and in vivo. Mechanistically, we demonstrate that MAVS O-GlcNAcylation is required for virus-induced MAVS K63-linked ubiquitination, thereby facilitating IRF3 activation and IFNß production. We further demonstrate that D-glucosamine, a commonly used dietary supplement, effectively protects mice against a range of lethal RNA viruses, including human influenza virus. Our study highlights a critical role of O-GlcNAcylation in regulating host antiviral immunity and validates D-glucosamine as a potential therapeutic for virus infections.