Acid-sensing ion channels (ASICs) are neuronal voltage-independent Na+ channels that are activated by extracellular acidification. ASICs play essential roles in a wide range of physiological processes, including sodium homeostasis, synaptic plasticity, neurodegeneration, and sensory transduction. Mambalgins, a family of three-finger toxins isolated from black mamba venom, specifically inhibit ASICs to exert strong analgesic effects in vivo, thus are thought to have potential therapeutic values against pain. However, the interaction and inhibition mechanism of mambalgin on ASICs remains elusive. Here, we report a cryo-electron microscopy (cryo-EM) structure of chicken ASIC1a (cASIC1a) in complex with mambalgin-1 toxin at 5.4 Å resolution. Our structure provides the first experimental evidence that mambalgin-1 interacts directly with the extracellular thumb domain of cASIC1a, rather than inserting into the acid-sensing pocket, as previously reported. Binding of mambalgin-1 leads to relocation of the thumb domain that could disrupt the acidic pocket of cASIC1a, illustrating an unusual inhibition mechanism of toxins on ASIC channels through an allosteric effect. These findings establish a structural basis for the toxicity of the mambalgins, and provide crucial insights for the development of new optimized inhibitors of ASICs.

Acid-sensing ion channels (ASICs) are proton-gated cation channels that are involved in diverse neuronal processes including pain sensing. The peptide toxin Mambalgin1 (Mamba1) from black mamba snake venom can reversibly inhibit the conductance of ASICs, causing an analgesic effect. However, the detailed mechanism by which Mamba1 inhibits ASIC1s, especially how Mamba1 binding to the extracellular domain affects the conformational changes of the transmembrane domain of ASICs remains elusive. Here, we present single-particle cryo-EM structures of human ASIC1a (hASIC1a) and the hASIC1a-Mamba1 complex at resolutions of 3.56 and 3.90 Å, respectively. The structures revealed the inhibited conformation of hASIC1a upon Mamba1 binding. The combination of the structural and physiological data indicates that Mamba1 preferentially binds hASIC1a in a closed state and reduces the proton sensitivity of the channel, representing a closed-state trapping mechanism.

Abnormal kynurenine (Kyn) metabolism has been closely linked to the pathogenesis of rheumatoid arthritis (RA). The aims of this study were to investigate the role of tryptophan 2,3-dioxygenase 2 (TDO2), a rate-limiting enzyme that converts tryptophan (Trp) to Kyn, in regulating fibroblast-like synoviocyte (FLS)-mediated synovial inflammation in autoimmune arthritis.

Sculpting a flat patch of membrane into an endocytic vesicle requires curvature generation on the cell surface, which is the primary function of the endocytosis machinery. Using super-resolved live cell fluorescence imaging, we demonstrate that curvature generation by individual clathrin-coated pits can be detected in real time within cultured cells and tissues of developing organisms. Our analyses demonstrate that the footprint of clathrin coats increases monotonically during the formation of pits at different levels of plasma membrane tension. These findings are only compatible with models that predict curvature generation at the early stages of endocytic clathrin pit formation. We also found that CALM adaptors associated with clathrin plaques form clusters, whereas AP2 distribution is more homogenous. Considering the curvature sensing and driving roles of CALM, we propose that CALM clusters may increase the strain on clathrin lattices locally, eventually giving rise to rupture and subsequent pit completion at the edges of plaques.

Marsdenia tenacissima (Roxb.) Moon, (M. tenacissima) a traditional herbal medicine, has been used for thousands of years. It is noted in Dian Nan Ben Cao that M. tenacissima is bitter in flavor and cold in property, and extracts possess diverse pharmacological effects, including immunomodulation and anti-tumor activities.

Heat stress has negative effects on the intestinal health of humans and animals. However, the impact of heat stress on intestinal microbial and metabolic changes remains elusive. Here, we investigated the cecal microbial and metabolic profiles in mice in response to heat stress.

Bilirubin encephalopathy is a severe complication of neonatal hyperbilirubinemia. With elevation of serum unconjugated bilirubin (UCB) levels, UCB crosses the blood-brain barrier and possibly leads to neurological dysfunction. Neuroinflammation is recognized as a prominent pathological feature in bilirubin encephalopathy. Recent studies have suggested that autophagy plays a crucial role in the inflammatory response. However, the potential effect of microglial autophagy in the pathogenesis of bilirubin encephalopathy remains uncertain. The in vitro findings verified that in primary cultured microglia, UCB significantly reduced the ratio of LC3B-II to LC3B-I and downregulated the expression of ATG5, Beclin-1, and ATG7, while increasing the expression of p62/SQSTM1. The results showed that UCB could decrease the number of mCherry-EGFP-LC3 positive puncta, even when chloroquine (CQ) was applied to block the microglial autophagy flux. Mechanistically, UCB was found to upregulate the expression of TLR4 and increase the phosphorylation levels of Akt and mammalian target of rapamycin (mTOR). Promoting microglial autophagy by treatment with Rapamycin (RAPA), an mTOR inhibitor, decreased the levels of NOD-like receptor protein 3 (NLRP3) inflammasome components and IL-1β, rescued microglial overactivation, and improved neurological functions. These data indicated that UCB could impact microglial autophagy via the Akt-mTOR signaling pathway and synergistically promote neuroinflammatory responses. Enhancing autophagy might disrupt the assembly of NLRP3 inflammasome, attenuate UCB-induced neuroinflammation, and improve the prognosis of model rats with bilirubin encephalopathy. In conclusion, this study implies that regulating microglial autophagy might be a promising therapeutic strategy for bilirubin encephalopathy.

Anti-angiogenesis is a promising therapeutic strategy for delaying tumour progression that offers, new hope for gastric cancer targeted therapy. The purpose of this study was to investigate the precise mechanism by which Kin of IRRE-like protein 1 (KIRREL) contributes to the development of gastric cancer, particularly in terms of tumour angiogenesis. Differential expression of KIRREL in tissues and cells was detected using quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry. A bioinformatics analysis was conducted to screen for the function and pathway enrichment of KIRREL in gastric cancer. Lentivirus-induced KIRREL silencing in SNU-5 cells and lentivirus-induced KIRREL overexpression in AGS cells were used to study the effect of KIRREL on the proliferation, cell cycle and angiogenesis of gastric cancer cells. Moreover, the expressions of PI3K, P-PI3K, AKT, P-AKT, mTOR, P-mTOR, HIF-1α and VEGF were also detected. Gastric cancer tissues and cells had high levels of KIRREL expression, which is associated with the proliferation, cell cycle and angiogenesis of gastric cancer cells. After silencing and overexpressing KIRREL in SNU-5 and AGS cells, respectively, the proliferation and angiogenesis of SNU-5 cells were inhibited, while the proliferation and angiogenesis of AGS cells were promoted. According to a bioinformatics analysis of the KIRREL gene, angiogenesis regulation and the PI3K/AKT pathway were highly connected. The PI3K/AKT/mTOR pathway was repressed and stimulated by KIRREL silencing and overexpression, respectively. IGF-1, an AKT agonist, and LY294002, an inhibitor, reversed the effects of KIRREL silencing and overexpression on the PI3K/AKT/mTOR pathway and on gastric cancer cell proliferation and angiogenesis. KIRREL may mediate the proliferation and angiogenesis of gastric cancer cells through the PI3K/AKT/mTOR signalling pathway. These findings could help in the further development of potential anti-angiogenesis targets.

This study aims to investigate the behavioral and neurophysiological changes accompanying the empathy for pain among individuals with insomnia in nonclinical samples, which has been scarcely explored in the existing literature despite the deleterious effects of sleep disturbance on social behavior, and interactions had been well-documented.

Vascular remodeling induced by long‑term hyperglycaemia is the main pathological process in diabetic vascular complications. Thus, vascular remodeling may be a potential therapeutic target in diabetes mellitus (DM) with macrovascular disease. The present study aimed to investigate the effect of RING finger protein 10 (RNF10) on vascular remodeling under conditions of chronic hyperglycaemia stimulation. We found that overexpression of RNF10 clearly decreased intimal thickness and attenuated vascular remodeling in DM. TUNEL staining showed that apoptosis was clearly inhibited, an effect that may be mediated by decreases in Bcl‑2 protein expression. Quantitative analysis demonstrated that overexpression of RNF10 could suppress inflammation by reducing the levels of TNF‑α, and MCP‑1 mRNA and NF‑κB protein. Meanwhile, overexpression of RNF10 prevented vascular smooth muscle cell (VSMC) hyperproliferation through the downregulation of cyclin D1 and CDK4 proteins. Notably, short hairpin RNF10 (shRNF10) greatly aggravated the pathological responses of diabetic vascular remodeling. These outcomes revealed that the differential expression of RNF10 had a completely opposite effect on vascular damage under hyperglycaemia, further displaying the core function of RNF10 in regulating vascular remodeling induced by diabetes. Consequently, RNF10 could be a novel target for the treatment of diabetic vascular complications.

The Wingless-type MMTV integration site family member 2b (Wnt2b) has been found to be a principal mediator of liver development and regeneration. However, the significance of Wnt2b in the pathogenesis of fibrosis-related liver diseases remains undefined. Here, we report that Wnt2b was highly expressed in the fibrotic liver tissues, exhibiting protective effects against activation of hepatic stellate cells (HSCs) and fibrosis progression. We identified a negative regulation of Wnt2b on the toll-like receptor 4 (TLR4) activation-mediated pro-fibrogenic effects. Wnt2b was shown not only to directly suppress LPS-induced HSCs activation, but also to inhibit TLR4-enhanced the sensitivity of HSCs to transforming growth factor beta (TGF-β). Mechanistic study showed that Wnt2b suppresses TLR4 signaling through inhibiting the expression of TLR4 as well as the activation of NF-κB and MAPKs. These findings provided new insights into the pathophysiology of liver fibrosis by characterizing Wnt2b as a novel endogenous suppressor of TLR4 signaling, maintaining tissue homeostasis during the early stage of hepatic fibrosis-associated liver diseases.

Airway inflammation is the major pathological feature of asthma. Thus, the current therapeutic strategy for asthma is to control inflammation. Limethason, an anti-inflammation drug, is widely used in rheumatoid arthritis treatment. The aim of the present study was to detect the anti-inflammatory effect and side effects of limethason on airways that were sensitized with ovalbumin in a murine model of chronic asthma. In the present study, BALB/c mice were sensitized with ovalbumin. Airway hyperresponsiveness was estimated, and hematoxylin and eosin staining, Periodic acid-Schiff staining and bronchoalveolar lavage were used to detect the effect on chronic asthma. Limethason effectively reduced airway hyperresponsiveness, and inhibited inflammatory cell infiltration and mucus secretion. Bronchoalveolar lavage fluid analysis revealed that limethason suppressed levels of airway eosinophils. In the period of treatment, limethason exhibited no influence on morphology of the femoral head, bone mineral content or bone mineral density, which were detected by histological studies and dual-energy X-ray absorptiometry. The index of liver, spleen, kidney, gastrocnemius and brown adipose tissue also demonstrated that limethason had no adverse effects on organs and tissues. The present study revealed that limethason could effectively reduce inflammation in an asthma mouse model without side effects. Therefore, limethason may have therapeutic potential for treating chronic asthma clinically.

Rheumatoid arthritis (RA) is characterized by the massive infiltration of various chronic inflammatory cells in synovia. In synovial fluid of patients with RA, M1 macrophages are dominant among all subtypes of macrophages, the mechanisms of macrophages polarization imbalance in RA has not been fully illuminated. The prostaglandin E2 (PGE2) augments M2 polarization in part via the cyclic adenosine monophosphate (cAMP)-cyclic AMP responsive element binding (CREB) signaling. However, previous study found constant stimulus of PGE2 on fibroblast-like synovial cells of adjuvant arthritis rats induced the decrease of cAMP, which is primarily caused by G protein-coupled receptor kinase 2 (GRK2)-induced EP4 over- desensitization. Whether GRK2 mediated-EP4 over-desensitization reduces the level of cAMP and inhibits M2 polarization in RA is unclear. Here we observed M1 macrophages were dominant in peritoneal macrophages (PMs), bone-marrow-derived macrophages (BMMs) and synovial macrophages of collagen-induced arthritis (CIA) mice. PGE2 stimulated M2 polarization via the EP4-cAMP-CREB in normal mice, while failed to promote M2 polarization in the PMs of CIA mice. Further, we found the EP4 over-desensitization stimulated by PGE2 induced abnormal PGE2-cAMP-CREB signaling as well as the imbalance of macrophage polarization. Targeted disruption of GRK2 in Raw264.7 (RAW) through GRK2 siRNA or CRISPR/Cas9 downregulated the M1 macrophage markers, upregulated the M2 macrophage markers and the EP4 membrane localization. The reduced M1/M2 ratio and increased p-CREB expression were observed in BMMs and PMs of GRK2+/- mice. This study highlighted a novel role of GRK2 in regulating macrophages function in RA and provided new idea for precision treatment of RA.

No abstract available

Dync1li1, a subunit of cytoplasmic dynein 1, is reported to play important roles in intracellular retrograde transport in many tissues. However, the roles of Dync1li1 in the mammalian cochlea remain uninvestigated. Here we first studied the expression pattern of Dync1li1 in the mouse cochlea and found that Dync1li1 is highly expressed in hair cells (HCs) in both neonatal and adult mice cochlea. Next, we used Dync1li1 knockout (KO) mice to investigate its effects on hearing and found that deletion of Dync1li1 leads to early onset of progressive HC loss via apoptosis and to subsequent hearing loss. Further studies revealed that loss of Dync1li1 destabilizes dynein and alters the normal function of dynein. In addition, Dync1li1 KO results in a thinner Golgi apparatus and the accumulation of LC3+ autophagic vacuoles, which triggers HC apoptosis. We also knocked down Dync1li1 in the OC1 cells and found that the number of autophagosomes were significantly increased while the number of autolysosomes were decreased, which suggested that Dync1li1 knockdown leads to impaired transportation of autophagosomes to lysosomes and therefore the accumulation of autophagosomes results in HC apoptosis. Our findings demonstrate that Dync1li1 plays important roles in HC survival through the regulation of autophagosome transportation.

The sustained release of a water-soluble drug is always a key and important issue in pharmaceutics. In this study, using cellulose acetate (CA) as a biomacromolecular matrix, core-sheath nanofibers were developed for providing a sustained release of a model drug-metformin hydrochloride (MET). The core-sheath nanofibers were fabricated using modified tri-axial electrospinning, in which a detachable homemade spinneret was explored. A process-nanostructure-performance relationship was demonstrated through a series of characterizations. The prepared nanofibers F2 could release 95% of the loaded MET through a time period of 23.4 h and had no initial burst effect. The successful sustained release performances of MET can be attributed to the following factors: (1) the reasonable application of insoluble CA as the filament-forming carrier, which determined that the drug was released through a diffusion manner; (2) the core-sheath nanostructure provided the possibility of both encapsulating the drug completely and realizing the heterogeneous distributions of MET in the nanofibers with a higher drug load core than the sheath; (3) the thickness of the sheath sections were able to be exploited for further manipulating a better drug extended release performance. The mechanisms for manipulating the drug sustained release behaviors are proposed. The present proof-of-concept protocols can pave a new way to develop many novel biomolecule-based nanostructures for extending the release of water-soluble drugs.

Exocarpium Citri Grandis (Huajuhong) is an authentic Chinese materia medica with excellent curative effects on relieving cough and reducing phlegm, which has been reputed as "Southern Ginseng" in China for a long history.

Staphylococcus aureus (S. aureus) is associated with recalcitrant chronic infection, especially in chronic rhinosinusitis (CRS). S. aureus infection and biofilms cause poorer postsurgical outcomes. We developed isosorbide mononitrate (ISMN) loaded nanoparticles conjugated with an anti-Staphylococcus aureus alpha-toxin (anti-S. aureus α-toxin) antibody that could target biofilms and investigated their anti-biofilm effect. Anti-S. aureus α-toxin antibody coupled immunoliposomes were generated. The effect of ISMN immunoliposomes on S. aureus biofilm formation and their anti-biofilm efficacy were examined using the crystal violet method and confocal laser scanning microscopy, respectively. Relative biofilm viability at 24 h was tested using the alamarBlue assay. The biofilm formation inhibitory effect on all concentrations of ISMN immunoliposomes was stronger than that of ISMN liposomes and free ISMN (P<0.05). At concentrations of 45 and 23 mg/ml, the inhibitory effect of ISMN liposomes was stronger than that of free ISMN (P<0.05), while at 11 mg/ml, the inhibitory effect of ISMN liposomes was the same as that of ISMN (P>0.05). At 45 and 23 mg/ml, the inhibitory effect of ISMN immunoliposomes on formed biofilms was greater than that of ISMN liposomes and free ISMN (P<0.05) and the inhibitory effect of ISMN liposomes was stronger than that of free ISMN (P<0.05). At 11 mg/ml, ISMN immunoliposomes, ISMN liposomes, and ISMN had the same effect on formed biofilms (P>0.05). In conclusion, ISMN immunoliposomes nearly completely destroy biofilm structure. ISMN immunoliposomes provide a promising approach for treating infectious diseases caused by S. aureus biofilms, including refractory CRS, chronic skin infection, sepsis, and osteomyelitis.

Ursodeoxycholic acid (UDCA) is the main therapeutic drug for cholestasis, but its use in children is controversial. We conducted this study to evaluate the efficacy and safety of ursodeoxycholic acid in children with cholestasis.

Heightened wakefulness in response to stressors is essential for survival but can also lead to sleep disorders like insomnia. The paraventricular thalamus (PVT) is both a critical thalamic area for wakefulness and a stress-sensitive brain region. However, whether the PVT and its neural circuitries are involved in controlling wakefulness in stress conditions remains unknown. Here, we find that PVT neurons projecting to the central amygdala (CeA) are activated by different stressors. These neurons are wakefulness-active and increase their activities upon sleep to wakefulness transitions. Optogenetic activation of the PVT-CeA circuit evokes transitions from sleep to wakefulness, whereas selectively silencing the activity of this circuit decreases time spent in wakefulness. Specifically, chemogenetic inhibition of CeA-projecting PVT neurons not only alleviates stress responses but also attenuates the acute stress-induced increase of wakefulness. Thus, our results demonstrate that the PVT-CeA circuit controls physiological wakefulness and modulates acute stress-induced heightened wakefulness.