Integrating plasma proteomics with genome-wide association data to identify novel drug targets for inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic disease that includes Crohn's disease (CD) and ulcerative colitis (UC). Although genome-wide association studies (GWASs) have identified many relevant genetic risk loci, the impact of these loci on protein abundance and their potential utility as clinical therapeutic targets remain uncertain. Therefore, this study aimed to investigate the pathogenesis of IBD and identify effective therapeutic targets through a comprehensive and integrated analysis. We systematically integrated GWAS data related to IBD, UC and CD (N = 25,305) by the study of de Lange KM with the human blood proteome (N = 7213) by the Atherosclerosis Risk in Communities (ARIC) study. Proteome-wide association study (PWAS), mendelian randomisation (MR) and Bayesian colocalisation analysis were used to identify proteins contributing to the risk of IBD. Integrative analysis revealed that genetic variations in IBD, UC and CD affected the abundance of five (ERAP2, RIPK2, TALDO1, CADM2 and RHOC), three (VSIR, HGFAC and CADM2) and two (MST1 and FLRT3) cis-regulated plasma proteins, respectively (P < 0.05). Among the proteins identified via Bayesian colocalisation analysis, CADM2 was found to be an important common protein between IBD and UC. A drug and five druggable target genes were identified from DGIdb after Bayesian colocalisation analysis. Our study's findings from genetic and proteomic approaches have identified compelling proteins that may serve as important leads for future functional studies and potential drug targets for IBD (UC and CD).

Deciphering the molecular landscape of rheumatoid arthritis offers new insights into the stratified treatment for the condition.

Background: For Rheumatoid Arthritis (RA), a long-term chronic illness, it is essential to identify and describe patient subtypes with comparable goal status and molecular biomarkers. This study aims to develop and validate a new subtyping scheme that integrates genome-scale transcriptomic profiles of RA peripheral blood genes, providing a fresh perspective for stratified treatments. Methods: We utilized independent microarray datasets of RA peripheral blood mononuclear cells (PBMCs). Up-regulated differentially expressed genes (DEGs) were subjected to functional enrichment analysis. Unsupervised cluster analysis was then employed to identify RA peripheral blood gene expression-driven subtypes. We defined three distinct clustering subtypes based on the identified 404 up-regulated DEGs. Results: Subtype A, named NE-driving, was enriched in pathways related to neutrophil activation and responses to bacteria. Subtype B, termed interferon-driving (IFN-driving), exhibited abundant B cells and showed increased expression of transcripts involved in IFN signaling and defense responses to viruses. In Subtype C, an enrichment of CD8+ T-cells was found, ultimately defining it as CD8+ T-cells-driving. The RA subtyping scheme was validated using the XGBoost machine learning algorithm. We also evaluated the therapeutic outcomes of biological disease-modifying anti-rheumatic drugs. Conclusions: The findings provide valuable insights for deep stratification, enabling the design of molecular diagnosis and serving as a reference for stratified therapy in RA patients in the future.

Quantitative radiomics analysis of imaging features in adults and children Mycoplasma pneumonia.

Purpose: This study aims to explore the value of clinical features, CT imaging signs, and radiomics features in differentiating between adults and children with Mycoplasma pneumonia and seeking quantitative radiomic representations of CT imaging signs. Materials and methods: In a retrospective analysis of 981 cases of mycoplasmal pneumonia patients from November 2021 to December 2023, 590 internal data (adults:450, children: 140) randomly divided into a training set and a validation set with an 8:2 ratio and 391 external test data (adults:121; children:270) were included. Using univariate analysis, CT imaging signs and clinical features with significant differences (p < 0.05) were selected. After segmenting the lesion area on the CT image as the region of interest, 1,904 radiomic features were extracted. Then, Pearson correlation analysis (PCC) and the least absolute shrinkage and selection operator (LASSO) were used to select the radiomic features. Based on the selected features, multivariable logistic regression analysis was used to establish the clinical model, CT image model, radiomic model, and combined model. The predictive performance of each model was evaluated using ROC curves, AUC, sensitivity, specificity, accuracy, and precision. The AUC between each model was compared using the Delong test. Importantly, the radiomics features and quantitative and qualitative CT image features were analyzed using Pearson correlation analysis and analysis of variance, respectively. Results: For the individual model, the radiomics model, which was built using 45 selected features, achieved the highest AUCs in the training set, validation set, and external test set, which were 0.995 (0.992, 0.998), 0.952 (0.921, 0.978), and 0.969 (0.953, 0.982), respectively. In all models, the combined model achieved the highest AUCs, which were 0.996 (0.993, 0.998), 0.972 (0.942, 0.995), and 0.986 (0.976, 0.993) in the training set, validation set, and test set, respectively. In addition, we selected 11 radiomics features and CT image features with a correlation coefficient r greater than 0.35. Conclusion: The combined model has good diagnostic performance for differentiating between adults and children with mycoplasmal pneumonia, and different CT imaging signs are quantitatively represented by radiomics.

Deep analysis of skin molecular heterogeneities and their significance on the precise treatment of patients with psoriasis.

Background: Psoriasis is a highly heterogeneous autoinflammatory disease. At present, heterogeneity in disease has not been adequately translated into concrete treatment options. Our aim was to develop and verify a new stratification scheme that identifies the heterogeneity of psoriasis by the integration of large-scale transcriptomic profiles, thereby identifying patient subtypes and providing personalized treatment options whenever possible. Methods: We performed functional enrichment and network analysis of upregulated differentially expressed genes using microarray datasets of lesional and non-lesional skin samples from 250 psoriatic patients. Unsupervised clustering methods were used to identify the skin subtypes. Finally, an Xgboost classifier was utilized to predict the effects of methotrexate and commonly prescribed biologics on skin subtypes. Results: Based on the 163 upregulated differentially expressed genes, psoriasis patients were categorized into three subtypes (subtypes A-C). Immune cells and proinflammatory-related pathways were markedly activated in subtype A, named immune activation. Contrastingly, subtype C, named stroma proliferation, was enriched in integrated stroma cells and tissue proliferation-related signaling pathways. Subtype B was modestly activated in all the signaling pathways. Notably, subtypes A and B presented good responses to methotrexate and interleukin-12/23 inhibitors (ustekinumab) but inadequate responses to tumor necrosis factor-α inhibitors and interleukin-17A receptor inhibitors. Contrastly, subtype C exhibited excellent responses to tumor necrosis factor-α inhibitors (etanercept) and interleukin-17A receptor inhibitors (brodalumab) but not methotrexate and interleukin-12/23 inhibitors. Conclusions: Psoriasis patients can be assorted into three subtypes with different molecular and cellular characteristics based on the heterogeneity of the skin's immune cells and the stroma, determining the clinical responses of conventional therapies.

Lipid mediator resolvin D2 inhibits ATP currents in rat primary sensory neurons.

Resolvin D2 (RvD2), an endogenous lipid mediator derived from docosahexaenoic acid, has been demonstrated to have analgesic effects. However, little is known about the mechanism underlying RvD2 in pain relief. Herein, we demonstrate that RvD2 targeted the P2X3 receptor as an analgesic. The electrophysiological activity of P2X3 receptors was suppressed by RvD2 in rat dorsal root ganglia (DRG) neurons. RvD2 pre-application dose-dependently decreased α,ß-methylene-ATP (α,ß-meATP)-induced inward currents. RvD2 remarkably decreased the maximum response to α,ß-meATP, without influencing the affinity of P2X3 receptors. RvD2 also voltage-independently suppressed ATP currents. An antagonist of the G protein receptor 18 (GPR18), O-1918, prevented the RvD2-induced suppression of ATP currents. Additionally, intracellular dialysis of the Gαi/o -protein antagonist pertussis toxin (PTX), the PKA antagonist H89, or the cAMP analog 8-Br-cAMP also blocked the RvD2-induced suppression. Furthermore, α,ß-meATP-triggered depolarization of membrane potential along with the action potential bursts in DRG neurons were inhibited by RvD2. Lastly, RvD2 attenuated spontaneous nociceptive behaviors as well as mechanical allodynia produced by α,ß-meATP in rats via the activation of the peripheral GPR18. These findings indicated that RvD2 inhibited P2X3 receptors in rat primary sensory neurons through GPR18, PTX-sensitive Gαi/o -proteins, and intracellular cAMP/PKA signaling, revealing a novel mechanism that underlies its analgesic effects by targeting P2X3 receptors.

ATAD1 inhibits hepatitis C virus infection by removing the viral TA-protein NS5B from mitochondria.

ATPase family AAA domain-containing protein 1 (ATAD1) maintains mitochondrial homeostasis by removing mislocalized tail-anchored (TA) proteins from the mitochondrial outer membrane (MOM). Hepatitis C virus (HCV) infection induces mitochondrial fragmentation, and viral NS5B protein is a TA protein. Here, we investigate whether ATAD1 plays a role in regulating HCV infection. We find that HCV infection has no effect on ATAD1 expression, but knockout of ATAD1 significantly enhances HCV infection; this enhancement is suppressed by ATAD1 complementation. NS5B partially localizes to mitochondria, dependent on its transmembrane domain (TMD), and induces mitochondrial fragmentation, which is further enhanced by ATAD1 knockout. ATAD1 interacts with NS5B, dependent on its three internal domains (TMD, pore-loop 1, and pore-loop 2), and induces the proteasomal degradation of NS5B. In addition, we provide evidence that ATAD1 augments the antiviral function of MAVS upon HCV infection. Taken together, we show that the mitochondrial quality control exerted by ATAD1 can be extended to a novel antiviral function through the extraction of the viral TA-protein NS5B from the mitochondrial outer membrane.

Group II metabotropic glutamate receptor activation attenuates acid-sensing ion channel currents in rat primary sensory neurons.

Acid-sensing ion channels (ASICs) play an important role in pain associated with tissue acidification. Peripheral inhibitory group II metabotropic glutamate receptors (mGluRs) have analgesic effects in a variety of pain conditions. Whether there is a link between ASICs and mGluRs in pain processes is still unclear. Herein, we show that the group II mGluR agonist LY354740 inhibited acid-evoked ASIC currents and action potentials in rat dorsal root ganglia neurons. LY354740 reduced the maximum current response to protons, but it did not change the sensitivity of ASICs to protons. LY354740 inhibited ASIC currents by activating group II mGluRs. We found that the inhibitory effect of LY354740 was blocked by intracellular application of the Gi/o protein inhibitor pertussis toxin and the cAMP analogue 8-Br-cAMP and mimicked by the protein kinase A (PKA) inhibitor H-89. LY354740 also inhibited ASIC3 currents in CHO cells coexpressing mGluR2 and ASIC3 but not in cells expressing ASIC3 alone. In addition, intraplantar injection of LY354740 dose-dependently alleviated acid-induced nociceptive behavior in rats through local group II mGluRs. Together, these results suggested that activation of peripheral group II mGluRs inhibited the functional activity of ASICs through a mechanism that depended on Gi/o proteins and the intracellular cAMP/PKA signaling pathway in rat dorsal root ganglia neurons. We propose that peripheral group II mGluRs are an important therapeutic target for ASIC-mediated pain.

A Compendium of Mucosal Molecular Characteristics Provides Novel Perspectives on the Treatment of Ulcerative Colitis.

BACKGROUND AND AIMS: Ulcerative colitis [UC] is a complex heterogeneous disease. This study aims to reveal the underlying molecular features of UC using genome-scale transcriptomes of patients with UC, and to develop and validate a novel stratification scheme. METHODS: A normalised compendium was created using colon tissue samples (455 patients with UC and 147 healthy controls [HCs]), covering genes from 10 microarray datasets. Upregulated differentially expressed genes [DEGs] were subjected to functional network analysis, wherein samples were grouped using unsupervised clustering. Additionally, the robustness of subclustering was further assessed by two RNA sequencing datasets [100 patients with UC and 16 HCs]. Finally, the Xgboost classifier was applied to the independent datasets to evaluate the efficacy of different biologics in patients with UC. RESULTS: Based on 267 upregulated DEGs of the transcript profiles, UC patients were classified into three subtypes [subtypes A-C] with distinct molecular and cellular signatures. Epithelial activation-related pathways were significantly enriched in subtype A [named epithelial proliferation], whereas subtype C was characterised as the immune activation subtype with prominent immune cells and proinflammatory signatures. Subtype B [named mixed] was modestly activated in all the signalling pathways. Notably, subtype A showed a stronger association with the superior response of biologics such as golimumab, infliximab, vedolizumab, and ustekinumab compared with subtype C. CONCLUSIONS: We conducted a deep stratification of mucosal tissue using the most comprehensive microarray and RNA sequencing data, providing critical insights into pathophysiological features of UC, which could serve as a template for stratified treatment approaches.

Group II metabotropic glutamate receptor activation suppresses ATP currents in rat dorsal root ganglion neurons.

P2X3 receptors and group II metabotropic glutamate receptors (mGluRs) have been found to be expressed in primary sensory neurons. P2X3 receptors participate in a variety of pain processes, while the activation of mGluRs has an analgesic effect. However, it's still unclear whether there is a link between them in pain. Herein, we reported that the group II mGluR activation inhibited the electrophysiological activity of P2X3 receptors in rat dorsal root ganglia (DRG) neurons. Group II mGluR agonist LY354740 concentration-dependently decreased P2X3 receptor-mediated and α,ß-methylene-ATP (α,ß-meATP)-evoked inward currents in DRG neurons. LY354740 significantly suppressed the maximum response of P2X3 receptor to α,ß-meATP, but did not change their affinity. Inhibition of ATP currents by LY354740 was blocked by the group II mGluR antagonist LY341495, also prevented by the intracellular dialysis of either the Gi/o protein inhibitor pertussis toxin, the cAMP analog 8-Br-cAMP, or the protein kinase A (PKA) inhibitor H-89. Moreover, LY354740 decreased α,ß-meATP-induced membrane potential depolarization and action potential bursts in DRG neurons. Finally, intraplantar injection of LY354740 also relieved α,ß-meATP-induced spontaneous nociceptive behaviors and mechanical allodynia in rats by activating peripheral group Ⅱ mGluRs. These results indicated that peripheral group II mGluR activation inhibited the functional activity of P2X3 receptors via a Gi/o protein and cAMP/PKA signaling pathway in rat DRG neurons, which revealed a novel mechanism underlying analgesic effects of peripheral group II mGluRs. This article is part of the Special Issue on "Purinergic Signaling: 50 years".

Deep stratification by transcriptome molecular characters for precision treatment of patients with systemic lupus erythematosus.

OBJECTIVES: To leverage the high clinical heterogeneity of systemic lupus erythematosus (SLE), we developed and validated a new stratification scheme by integrating genome-scale transcriptomic profiles to identify patient subtypes sharing similar transcriptomic markers and drug targets. METHODS: A normalized compendium of transcription profiles was created from peripheral blood mononuclear cells (PBMCs) of 1046 SLE patients and 86 healthy controls (HCs), covering an intersection of 13 689 genes from six microarray datasets. Upregulated differentially expressed genes were subjected to functional and network analysis in which samples were grouped using unsupervised clustering to identify patient subtypes. Then, clustering stability was evaluated by the stratification of six integrated RNA-sequencing datasets using the same method. Finally, the Xgboost classifier was applied to the independent datasets to identify factors associated with treatment outcomes. RESULTS: Based on 278 upregulated DEGs of the transcript profiles, SLE patients were classified into three subtypes (subtype A-C) each with distinct molecular and cellular signatures. Neutrophil activation-related pathways were markedly activated in subtype A (named NE-driving), whereas lymphocyte and IFN-related pathways were more enriched in subtype B (IFN-driving). As the most severe subtype, subtype C [NE-IFN-dual-driving (Dual-driving)] shared functional mechanisms with both NE-driving and IFN-driving, which was closely associated with clinical features and could be used to predict the responses of treatment. CONCLUSION: We developed the largest cohesive SLE transcriptomic compendium for deep stratification using the most comprehensive microarray and RNA sequencing datasets to date. This result could guide future design of molecular diagnosis and the development of stratified therapy for SLE patients.

NLRC5 restricts dengue virus infection by promoting the autophagic degradation of viral NS3 through E3 ligase CUL2 (cullin 2).

NLRC5 has been reported to be involved in antiviral immunity; however, the underlying mechanism remains poorly understood. Here, we investigated the functional role of NLRC5 in the infection of a flavivirus, dengue virus (DENV). We found that the expression of NLRC5 was strongly induced by virus infection and IFNB or IFNG stimulation in different cell lines. Overexpression of NLRC5 remarkably suppressed DENV infection, whereas knockout of NLRC5 led to a significant increase in DENV infection. Mechanistic study revealed that NLRC5 interacted with the viral nonstructural protein 3 (NS3) protease domain and mediated degradation of NS3 through a ubiquitin-dependent selective macroautophagy/autophagy pathway. We demonstrated that NLRC5 recruited the E3 ubiquitin ligase CUL2 (cullin 2) to catalyze K48-linked poly-ubiquitination of the NS3 protease domain, which subsequently served as a recognition signal for cargo receptor TOLLIP-mediated selective autophagic degradation. Together, we have demonstrated that NLRC5 exerted an antiviral effect by mediating the degradation of a multifunctional protein of DENV, providing a novel antiviral signal axis of NLRC5-CUL2-NS3-TOLLIP. This study expands our understanding of the regulatory network of NLRC5 in the host defense against virus infection.

H2O2-assisted detection of melamine using fluorescent probe based on corn cob carbon dots-Ionic Liquid-Silver nanoparticles.

In this work, a new sustainable melamine detection method was developed. Biomass-derived carbon dots (CDs) were successfully prepared by ionic liquid (1-Allyl-3-methylimidazolium chloride, IL) hydrothermal method using agricultural waste corn cob as the carbon source, and combined with silver nanoparticles (AgNPs) to construct fluorescent probe CDs@IL-AgNPs. The probe was characterized and the formation mechanism of the probe was discussed. The direct detection of H2O2 and the indirect sensitive detection of melamine were realized. The detection limit of melamine was 0.94 µmol/L, which is far lower than the minimum allowable amount of melamine in milk powder (7.95 µmol/L). The high sensitivity and selectivity probe was used to detect melamine in commercial dairy products, and the recovery rate of standard addition was between 94 % and 110 %. This study provides valuable new application ideas for the detection of melamine in dairy products and the low-carbon and environmentally friendly treatment of agricultural waste.

An updated analysis of the association between CD2-associated protein gene rs9349407 polymorphism and Alzheimer's disease in Chinese population.

Background: Since 2011, three large-scale genome-wide association studies (GWAS) have confirmed that the CD2AP rs9349407 polymorphism is significantly connected with Alzheimer's disease (AD) in individuals of European descent. Subsequently, this association has been replicated in European populations, but is unclear whether it can be replicated in Chinese. Recently, the correlation between rs9349407 and AD in the Chinese population has become a research hotspot. Objective: To explore the association between rs9349407 polymorphism and AD in the Chinese population. Materials and methods: Firstly, based on the exclusion and inclusion criteria, we selected 11 independent studies from 8 articles exploring the correlation between rs9349407 variation and AD in Chinese. Secondly, we conducted a meta-analysis based on fixed and random effect models and conducted a heterogeneity test. Thirdly, we used the additive model, dominant model, and recessive model for subgroup analysis. Results: We demonstrated that the CD2AP rs9349407 polymorphism increases AD susceptibility in Chinese populations (OR = 1.33, 95% CI = 1.08-1.64, P = 7.45E-03), which is consistent with the effect observed in Caucasian populations. Additionally, subgroup analysis showed that rs9349407 under the additive model (GG + CC vs. GC, OR = 0.76, 95% CI = 0.61-0.97, P = 2.04E-02) and dominant model (GG + GC vs. CC, OR = 0.49, 95% CI = 0.32-0.74, P = 8.51E-04) were also significantly correlated with AD susceptibility, but not under the recessive model (GG vs. GC + CC, OR = 0.77, 95% CI = 0.58-1.03, P = 7.44E-02). Conclusion: These existing data suggest that rs9349307 is significantly correlated with the susceptibility to AD in the Chinese population, but future studies with large samples are needed to confirm our findings.

A1 Adenosine Receptor Activation Inhibits P2X3 Receptor-Mediated ATP Currents in Rat Dorsal Root Ganglion Neurons.

Purinergic signaling is involved in multiple pain processes. P2X3 receptor is a key target in pain therapeutics, while A1 adenosine receptor signaling plays a role in analgesia. However, it remains unclear whether there is a link between them in pain. The present results showed that the A1 adenosine receptor agonist N6-cyclopentyladenosine (CPA) concentration dependently suppressed P2X3 receptor-mediated and α,ß-methylene-ATP (α,ß-meATP)-evoked inward currents in rat dorsal root ganglion (DRG) neurons. CPA significantly decreased the maximal current response to α,ß-meATP, as shown a downward shift of the concentration-response curve for α,ß-meATP. CPA suppressed ATP currents in a voltage-independent manner. Inhibition of ATP currents by CPA was completely prevented by the A1 adenosine receptor antagonist KW-3902, and disappeared after the intracellular dialysis of either the Gi/o protein inhibitor pertussis toxin, the adenylate cyclase activator forskolin, or the cAMP analog 8-Br-cAMP. Moreover, CPA suppressed the membrane potential depolarization and action potential bursts, which were induced by α,ß-meATP in DRG neurons. Finally, CPA relieved α,ß-meATP-induced nociceptive behaviors in rats by activating peripheral A1 adenosine receptors. These results indicated that CPA inhibited the activity of P2X3 receptors in rat primary sensory neurons by activating A1 adenosine receptors and its downstream cAMP signaling pathway, revealing a novel peripheral mechanism underlying its analgesic effect.

Development and Characterization of a Genetically Stable Infectious Clone for a Genotype I Isolate of Dengue Virus Serotype 1.

Dengue virus (DENV) is primarily transmitted by the bite of an infected mosquito of Aedes aegypti and Aedes albopictus, and symptoms caused may range from mild dengue fever to severe dengue hemorrhagic fever and dengue shock syndrome. Reverse genetic system represents a valuable tool for the study of DENV virology, infection, pathogenesis, etc. Here, we generated and characterized an eukaryotic-activated full-length infectious cDNA clone for a DENV serotype 1 (DENV-1) isolate, D19044, collected in 2019. Initially, nearly the full genome was determined by sequencing overlapping RT-PCR products, and was classified to be genotype I DENV-1. D19044 wild-type cDNA clone (D19044_WT) was assembled by four subgenomic fragments, in a specific order, into a low-copy vector downstream the CMV promoter. D19044_WT released the infectious virus at a low level (1.26 × 103 focus forming units per milliliter [FFU/mL]) following plasmid transfection of BHK-21 cells. Further adaptation by consecutive virus passages up to passage 37, and seven amino acid substitutions (7M) were identified from passage-recovered viruses. The addition of 7M (D19044_7M) greatly improved viral titer (7.5 × 104 FFU/mL) in transfected BHK-21 culture, and virus infections in 293T, Huh7.5.1, and C6/36 cells were also efficient. D19044_7M plasmid was genetically stable in transformant bacteria after five transformation-purification cycles, which did not change the capacity of producing infectious virus. Moreover, the D19044_7M virus was inhibited by mycophenolic acid in a dose-dependent manner. In conclusion, we have developed a DNA-launched full-length infectious clone for a genotype I isolate of DENV-1, with genetic stability in transformant bacteria, thus providing a useful tool for the study of DENV-1.

Potentiation of ASIC currents by lysophosphatidic acid in rat dorsal root ganglion neurons.

Lysophosphatidic acid (LPA) is a phospholipid which has been implicated in pain. Acid-sensing ion channels (ASICs) are important players in pain associated with tissue acidification. However, it is still unclear whether there is a link between LPA signaling and ASICs in pain processes. Herein, we show that a functional interaction between them in rat dorsal root ganglia (DRG) neurons. Pre-application of LPA enhanced ASIC-mediated and acid-evoked inward currents in a concentration-dependent manner. LPA shifted the concentration-response curve for protons upwards, with an increase of 41.79 ± 4.71% in the maximal current response of ASICs to protons in the presence of LPA. Potentiation of ASIC currents by LPA was blocked by the LPA1 receptor antagonist Ki16198, but not by the LPA2 receptor antagonist H2L5185303. The LPA-induced potentiation was also prevented by intracellular application of either G protein inhibitor or protein kinase C (PKC) inhibitor, but not by Rho inhibitor. LPA also enhanced ASIC3 currents in CHO cells co-expressing ASIC3 and LPA1 receptors, but not in cells expressing ASIC3 alone. Moreover, LPA increased the amplitude of the depolarization and the number of spikes induced by acid stimuli. Finally, LPA exacerbated acid-induced nociceptive behaviors in rats. These results suggested that LPA enhanced ASIC-mediated electrophysiological activity and nociception via a LPA1 receptor and its downstream PKC rather than Rho signaling pathway, which provided a novel peripheral mechanism underlying the sensitization of pain.

Enhancement of P2X3 Receptor-Mediated Currents by Lysophosphatidic Acid in Rat Primary Sensory Neurons.

Lysophosphatidic acid (LPA), a lipid metabolite, plays a role in both neuropathic and inflammatory pain through LPA1 receptors. P2X3 receptor has also been shown to participate in these pathological processes. However, it is still unclear whether there is a link between LPA signaling and P2X3 receptors in pain. Herein, we show that a functional interaction between them in rat dorsal root ganglia (DRG) neurons. Pretreatment of LPA concentration-dependently enhanced α,ß-methylene-ATP (α,ß-meATP)-induced inward currents mediated by P2X3 receptors. LPA significantly increased the maximal current response of α,ß-meATP, showing an upward shift of the concentration-response curve for α,ß-meATP. The LPA enhancement was independent on the clamping-voltage. Enhancement of P2X3 receptor-mediated currents by LPA was prevented by the LPA1 receptor antagonist Ki16198, but not by the LPA2 receptor antagonist H2L5185303. The LPA-induced potentiation was also attenuated by intracellular dialysis of either G-protein inhibitor or protein kinase C (PKC) inhibitor, but not by Rho inhibitor. Moreover, LPA significantly changed the membrane potential depolarization and action potential burst induced by α,ß-meATP in DRG neurons. Finally, LPA exacerbated α,ß-meATP- induced nociceptive behaviors in rats. These results suggested that LPA potentiated the functional activity of P2X3 receptors in rat primary sensory neurons through activation of the LPA1 receptor and its downstream PKC rather than Rho signaling pathway, indicating a novel peripheral mechanism underlying the sensitization of pain.

Suppression of P2X3 receptor-mediated currents by the activation of α2A -adrenergic receptors in rat dorsal root ganglion neurons.

AIMS: The α2 -adrenergic receptor (α2 -AR) agonists have been shown to be effective in the treatment of various pain. For example, dexmedetomidine (DEX), a selective α2A -AR agonist, can be used for peripheral analgesia. However, it is not yet fully elucidated for the precise molecular mechanisms. P2X3 receptor is a major receptor processing nociceptive information in primary sensory neurons. Herein, we show that a functional interaction of α2A -ARs and P2X3 receptors in dorsal root ganglia (DRG) neurons could contribute to peripheral analgesia of DEX. METHODS: Electrophysiological recordings were carried out on rat DRG neurons, and nociceptive behavior was quantified in rats. RESULTS: The activation of α2A -ARs by DEX suppressed P2X3 receptor-mediated and α,ß-methylene-ATP (α,ß-meATP)-evoked inward currents in a concentration-dependent and voltage-independent manner. Pre-application of DEX shifted the α,ß-meATP concentration-response curve downwards, with a decrease of 50.43 ± 4.75% in the maximal current response of P2X3 receptors to α,ß-meATP in the presence of DEX. Suppression of α,ß-meATP-evoked currents by DEX was blocked by the α2A -AR antagonist BRL44408 and prevented by intracellular application of the Gi/o protein inhibitor pertussis toxin, the adenylate cyclase activator forskolin, and the cAMP analog 8-Br-cAMP. DEX also suppressed α,ß-meATP-evoked action potentials through α2A -ARs in rat DRG neurons. Finally, the activation of peripheral α2A -ARs by DEX had an analgesic effect on the α,ß-meATP-induced nociception. CONCLUSIONS: These results suggested that activation of α2A -ARs by DEX suppressed P2X3 receptor-mediated electrophysiological and behavioral activity via a Gi/o proteins and cAMP signaling pathway, which was a novel potential mechanism underlying analgesia of peripheral α2A -AR agonists.

Suppression of ASIC activity by the activation of A1 adenosine receptors in rat primary sensory neurons.

Peripheral A1 adenosine receptor signaling has been shown to have analgesic effects in a variety of pain conditions. However, it is not yet fully elucidated for the precise molecular mechanisms. Acid sensing ion channels (ASICs) are expressed predominantly in nociceptive sensory neurons responding to protons. Given that both A1 adenosine receptors and ASICs are present in dorsal root ganglia (DRG) neurons, we therefore investigated whether there was a cross-talk between the two types of receptors. Herein, electrophysiological recordings showed that the A1 adenosine receptor agonist N6-cyclopentyladenosine (CPA) suppressed acid-induced currents and action potentials, which were mediated by ASICs, in rat DRG neurons. CPA inhibited the maximum response to protons, as shown a downward shift of concentration-response curve for protons. The CPA-induced suppression of ASIC currents was blocked by the A1 adenosine receptor antagonist KW-3902 and also prevented by intracellular application of the Gi/o-protein inhibitor pertussis toxin, the adenylate cyclase activator forskolin, and the cAMP analog 8-Br-cAMP. Finally, intraplantar pretreatment of CPA dose-dependently relieved acid-induced nociceptive responses in rats through peripheral A1 adenosine receptors. These results suggested that CPA suppressed ASICs via A1 adenosine receptors and intracellular Gi/o-proteins and cAMP signaling cascades in rat DRG neurons, which was a novel potential mechanism underlying analgesia of peripheral A1 adenosine receptors.

Development of cell culture infectious clones for hepatitis C virus genotype 1b and transcription analysis of 1b-infected hepatoma cells.

Globally, hepatitis C virus (HCV) genotype 1b is the most prevalent, and its infection has been found to associate with a higher risk of hepatocellular carcinoma (HCC) than other genotype viruses. However, an efficient infectious HCV genotype 1b culture system is unavailable, which has largely hampered the study of this important genotype virus. In this study, by using a systematic approach combining the sequences of infectious 1a TNcc clone and adaptive mutations, we succeeded in culture adaption of two full-length 1b clones for the reference strain Con1 and a clinical isolate A6, and designated as Con1cc and A6cc, respectively. Con1cc and A6cc replicated efficiently in hepatoma Huh7.5.1 cells, released HCV infectivity titers of 104.1 and 103.72 focus forming units per milliliter, respectively, and maintained the engineered mutations after passages. Both viruses responded to sofosbuvir and velpatasvir in a dose-dependent manner. With culture infectious 1b clones, we characterized the transcriptomes of 1b Con1cc-infected cells, in comparison with 2a-infected and uninfected cells. In conclusion, we have developed two infectious clones for genotype 1b and shown a novel strategy for culture adaptation of HCV isolates by using a genetically close backbone sequence. Furthermore, this study provides transcriptional landscape of HCV 1b-infected hepatoma cells facilitating the study of genotype 1b infection.