Two Peaks of Seasonal Influenza Epidemics - China, 2023.

Introduction: Influenza is a communicable respiratory disease that causes annual epidemics and occasional unpredictable pandemics. This study examines the occurrence of two unexpected influenza peaks within the year 2023. Methods: Influenza-like illness (ILI) data were reported, and specimens of ILI were collected by designated surveillance hospitals. Positive cases were confirmed using real-time reverse transcription polymerase chain reaction (rRT-PCR) testing conducted at national surveillance network laboratories. The data were then submitted to the Chinese Influenza Surveillance Information System. Results: From December 2022 to January 2023, influenza activity was minimal until a spring epidemic began in February, peaking in late March. The outbreak spread from the north to the south, with A(H1N1)pdm09 being the predominant strain and A(H3N2) also circulating concurrently. The positivity rate in northern and southern provincial-level administrative divisions (PLADs) reached 60.0% (week 10) and 60.2% (week 13), respectively, before dropping to below 5% from May to August. Subsequently, rates surged starting in week 41 in the south and week 44 in the north, peaking at 54.4% (week 50) and 44.0% (week 49), respectively, and remained high until the end of 2023. A(H3N2) became the prevailing strain, with a notable increase in B/Victoria lineage viruses from December, resulting in two peaks during the 2023 influenza season. Conclusions: The pattern of the influenza epidemic shifted due to the coronavirus disease 2019 (COVID-19) outbreak and is gradually returning to its usual seasonal and intensity patterns. It is, therefore, crucial to continuously strengthen influenza surveillance, enhance the influenza surveillance network, and lay the groundwork for advancing integrated surveillance of multiple pathogens in China.

R229I substitution from oseltamivir induction in HA1 region significantly increased the fitness of a H7N9 virus bearing NA 292K.

The proportion of human isolates with reduced neuraminidase inhibitors (NAIs) susceptibility in highly pathogenic avian influenza (HPAI) H7N9 virus was high. These drug-resistant strains showed good replication capacity without serious loss of fitness. In the presence of oseltamivir, R229I substitution were found in HA1 region of the HPAI H7N9 virus before NA R292K appeared. HPAI H7N9 or H7N9/PR8 recombinant viruses were developed to study whether HA R229I could increase the fitness of the H7N9 virus bearing NA 292K. Replication efficiency was assessed in MDCK or A549 cells. Neuraminidase enzyme activity and receptor-binding ability were analyzed. Pathogenicity in C57 mice was evaluated. Antigenicity analysis was conducted through a two-way HI test, in which the antiserum was obtained from immunized ferrets. Transcriptomic analysis of MDCK infected with HPAI H7N9 24hpi was done. It turned out that HA R229I substitution from oseltamivir induction in HA1 region increased (1) replication ability in MDCK(P < 0.05) and A549(P < 0.05), (2) neuraminidase enzyme activity, (3) binding ability to both α2,3 and α2,6 receptor, (4) pathogenicity to mice(more weight loss; shorter mean survival day; viral titer in respiratory tract, P < 0.05; Pathological changes in pneumonia), (5) transcriptome response of MDCK, of the H7N9 virus bearing NA 292K. Besides, HA R229I substitution changed the antigenicity of H7N9/PR8 virus (>4-fold difference of HI titre). It indicated that through the fine-tuning of HA-NA balance, R229I increased the fitness and changed the antigenicity of H7N9 virus bearing NA 292K. Public health attention to this mechanism needs to be drawn.

The Multi-Kingdom Microbiome of Wintering Migratory Birds in Poyang Lake, China.

Wild birds are a natural reservoir for zoonotic viruses. To clarify the role of migratory birds in viruses spread in Poyang Lake, we investigated the microbiome of 250 wild bird samples from 19 species in seven orders. The bacterial and viral content abundance and diversity were preliminarily evaluated by Kraken2 and Bracken. After de novo assembly by Megahit and Vamb, viral contigs were identified by CheckV. The reads remapped to viral contigs were quantified using Bowtie2. The bacterial microbiome composition of the samples covers 1526 genera belonging to 175 bacterial orders, while the composition of viruses covers 214 species belonging to 22 viral families. Several taxonomic biomarkers associated with avian carnivory, oral sampling, and raptor migration were identified. Additionally, 17 complete viral genomes belonging to Astroviridae, Caliciviridae, Dicistroviridae, Picornaviridae, and Tombusviridae were characterized, and their phylogenetic relationships were analyzed. This pioneering metagenomic study of migratory birds in Poyang Lake, China illuminates the diverse microbial landscape within these birds. It identifies potential pathogens, and uncovers taxonomic biomarkers relevant to varied bird habitats, feeding habits, ecological classifications, and sample types, underscoring the public health risks associated with wintering migratory birds.

Reported human infections of H9N2 avian influenza virus in China in 2021.

Introduction: The continued emergence of human infections of H9N2 avian influenza virus (AIV) poses a serious threat to public health. The prevalent Y280/G9 lineage of H9N2 AIV in Chinese poultry can directly bind to human receptors, increasing the risk of spillover infections to humans. Since 2013, the number of human cases of H9N2 avian influenza has been increasing continuously, and in 2021, China reported the highest number of human cases, at 25. Methods: In this study, we analyzed the age, geographic, temporal, and sex distributions of humans with H9N2 avian influenza in 2021 using data from the National Influenza Center (Beijing, China). We also conducted evolutionary, gene homology, and molecular characterization analyses of the H9N2 AIVs infecting humans. Results: Our findings show that children under the age of 12 accounted for 80% of human cases in 2021, and females were more frequently affected than males. More cases occurred in winter than in summer, and most cases were concentrated in southern China. Human-infecting H9N2 viruses showed a high level of genetic homology and belonged to the prevalent G57 genotype. Several additional α2,6-SA-binding sites and sites of mammalian adaptation were also identified in the genomes of human-infecting H9N2 viruses. Discussion: Therefore, continuous monitoring of H9N2 AIV and the implementation of further measures to control the H9N2 virus in poultry are essential to reduce the interspecies transmission of the virus.

Dysfunction of inhibitory interneurons contributes to synaptic plasticity via GABABR-pNR2B signaling in a chronic migraine rat model.

Background: According to our previous study, the loss of inhibitory interneuron function contributes to central sensitization in chronic migraine (CM). Synaptic plasticity is a vital basis for the occurrence of central sensitization. However, whether the decline in interneuron-mediated inhibition promotes central sensitization by regulating synaptic plasticity in CM remains unclear. Therefore, this study aims to explore the role of interneuron-mediated inhibition in the development of synaptic plasticity in CM. Methods: A CM model was established in rats by repeated dural infusion of inflammatory soup (IS) for 7 days, and the function of inhibitory interneurons was then evaluated. After intraventricular injection of baclofen [a gamma-aminobutyric acid type B receptor (GABABR) agonist] or H89 [a protein kinase A (PKA) inhibitor), behavioral tests were performed. The changes in synaptic plasticity were investigated by determining the levels of the synapse-associated proteins postsynaptic density protein 95 (PSD95), synaptophysin (Syp) and synaptophysin-1(Syt-1)]; evaluating the synaptic ultrastructure by transmission electron microscopy (TEM); and determining the density of synaptic spines via Golgi-Cox staining. Central sensitization was evaluated by measuring calcitonin gene-related peptide (CGRP), brain-derived neurotrophic factor (BDNF), c-Fos and substance P (SP) levels. Finally, the PKA/Fyn kinase (Fyn)/tyrosine-phosphorylated NR2B (pNR2B) pathway and downstream calcium-calmodulin-dependent kinase II (CaMKII)/c-AMP-responsive element binding protein (pCREB) signaling were assessed. Results: We observed dysfunction of inhibitory interneurons, and found that activation of GABABR ameliorated CM-induced hyperalgesia, repressed the CM-evoked elevation of synapse-associated protein levels and enhancement of synaptic transmission, alleviated the CM-triggered increases in the levels of central sensitization-related proteins, and inhibited CaMKII/pCREB signaling via the PKA/Fyn/pNR2B pathway. The inhibition of PKA suppressed the CM-induced activation of Fyn/pNR2B signaling. Conclusion: These data reveal that the dysfunction of inhibitory interneurons contributes to central sensitization by regulating synaptic plasticity through the GABABR/PKA/Fyn/pNR2B pathway in the periaqueductal gray (PAG) of CM rats. Blockade of GABABR-pNR2B signaling might have a positive influence on the effects of CM therapy by modulating synaptic plasticity in central sensitization.

SARS-CoV-2 Surveillance Through China Influenza Surveillance Information System - China, December 1, 2022 to February 12, 2023.

Introduction: The World Health Organization (WHO) proposed using influenza surveillance systems to carry out coronavirus disease 2019 (COVID-19) surveillance due to the similarity between the two diseases in some respiratory symptoms. To assess the prevalence of COVID-19, we analyzed the influenza-like illness (ILI) and positive rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detections in ILI patients reported to the influenza Surveillance Information System (CNISIS) since late 2022. Methods: Data related to ILI were reported by national surveillance sentinel hospitals. Positive testing for SARS-CoV-2 and influenza viruses was conducted using real-time reverse transcription polymerase chain reaction (rRT-PCR) detection by the national influenza surveillance network laboratories. Surveillance data were reported to CNISIS. Results: Beginning on December 12, 2022 (Week 50), the ILI percentage increased dramatically, peaking in Week 51 at 12.1%. Subsequently, the ILI percentage began to decline rapidly from Week 52, 2022, and by Week 6, 2023 (February 6-12), the ILI and ILI percentage had returned to the levels observed at the beginning of December 2022. From December 1, 2022 to February 12, 2023, 115,844 specimens were tested for both SARS-CoV-2 and influenza virus. Of these, 30,381 (26.2%) were positive for SARS-CoV-2 and 1,763 (1.5%) were positive for influenza virus. The positive rate of SARS-CoV-2 tests peaked at 74.1% around December 23 and 25. Conclusions: Sentinel-based surveillance, previously established for influenza, is an effective way to track the circulation trend of SARS-CoV-2 during community-level epidemics. There was no co-prevalence of SARS-CoV-2 and influenza virus during the outbreak of SARS-CoV-2, even during the winter influenza season. However, it is important to remain vigilant for the potential rise of influenza activities following the COVID-19 epidemic.

Activation of CB1R alleviates central sensitization by regulating HCN2-pNR2B signaling in a chronic migraine rat model.

BACKGROUND: Central sensitization has been widely accepted as an underlying pathophysiological mechanism of chronic migraine (CM), activation of cannabinoid type-1 receptor (CB1R) exerts antinociceptive effects by relieving central sensitization in many pain models. However, the role of CB1R in the central sensitization of CM is still unclear. METHODS: A CM model was established by infusing inflammatory soup (IS) into the dura of male Wistar rats for 7 days, and hyperalgesia was assessed by the mechanical and thermal thresholds. In the periaqueductal gray (PAG), the mRNA and protein levels of CB1R and hyperpolarization-activated cyclic nucleotide-gated cation channel 2 (HCN2) were measured by qRT-PCR and western blotting. After intraventricular injection of Noladin ether (NE) (a CB1R agonist), ZD 7288 (an HCN2 blocker), and AM 251 (a CB1R antagonist), the expression of tyrosine phosphorylation of N-methyl-D-aspartate receptor subtype 2B (pNR2B), calcium-calmodulin-dependent kinase II (CaMKII), and phosphorylated cAMP-responsive element binding protein (pCREB) was detected, and central sensitization was evaluated by the expression of calcitonin gene-related peptide (CGRP), c-Fos, and substance P (SP). Synaptic-associated protein (postsynaptic density protein 95 (PSD95) and synaptophysin (Syp)) and synaptic ultrastructure were detected to explore synaptic plasticity in central sensitization. RESULTS: We observed that the mRNA and protein levels of CB1R and HCN2 were both significantly increased in the PAG of CM rats. The application of NE or ZD 7288 ameliorated IS-induced hyperalgesia; repressed the pNR2B/CaMKII/pCREB pathway; reduced CGRP, c-Fos, SP, PSD95, and Syp expression; and inhibited synaptic transmission. Strikingly, the application of ZD 7288 relieved AM 251-evoked elevation of pNR2B, CGRP, and c-Fos expression. CONCLUSIONS: These data reveal that activation of CB1R alleviates central sensitization by regulating HCN2-pNR2B signaling in CM rats. The activation of CB1R might have a positive influence on the prevention of CM by mitigating central sensitization.

Enhanced environmental surveillance for avian influenza A/H5, H7 and H9 viruses in Guangxi, China, 2017-2019.

We conducted environmental surveillance to detect avian influenza viruses circulating at live poultry markets (LPMs) and poultry farms in Guangxi Autonomous Region, China, where near the China-Vietnam border. From November through April 2017-2018 and 2018-2019, we collected environmental samples from 14 LPMs, 4 poultry farms, and 5 households with backyard poultry in two counties of Guangxi and tested for avian influenza A, H5, H7, and H9 by real-time reverse transcription-polymerase chain reaction (rRT-PCR). In addition, we conducted four cross-sectional questionnaire surveys among stall owners on biosecurity practices in LPMs of two study sites. Among 16,713 environmental specimens collected and tested, the median weekly positive rate for avian influenza A was 53.6% (range = 33.5% - 66.0%), including 25.2% for H9, 4.9% for H5, and 21.2% for other avian influenza viruses A subtypes, whereas a total of two H7 positive samples were detected. Among the 189 LPM stalls investigated, most stall owners (73.0%) sold chickens and ducks. Therefore, continued surveillance of the avian influenza virus is necessary for detecting and responding to emerging trends in avian influenza virus epidemiology.

Apparent diffusion coefficient histogram analysis for differentiating solid ovarian tumors.

Objective: To evaluate the utility of apparent diffusion coefficient (ADC) histogram analysis to differentiate between three types of solid ovarian tumors: granulosa cell tumors (GCTs) of the ovary, ovarian fibromas, and high-grade serous ovarian carcinomas (HGSOCs). Methods: The medical records of 11 patients with GCTs of the ovary (regions of interest [ROI-cs], 137), 61 patients with ovarian fibromas (ROI-cs, 161), and 14 patients with HGSOCs (ROI-cs, 113) confirmed at surgery and histology who underwent diffusion-weighted imaging were retrospectively reviewed. Histogram parameters of ADC maps (ADCmean, ADCmax, ADCmin) were estimated and compared using the Kruskal-WallisH test and Mann-Whitney U test. The area under the curve of receiver operating characteristic curves was used to assess the diagnostic performance of ADC parameters for solid ovarian tumors. Results: There were significant differences in ADCmean, ADCmax and ADCmin values between GCTs of the ovary, ovarian fibromas, and HGSOCs. The cutoff ADCmean value for differentiating a GCT of the ovary from an ovarian fibroma was 0.95×10-3 mm2/s, for differentiating a GCT of the ovary from an HGSOC was 0.69×10-3 mm2/s, and for differentiating an ovarian fibroma from an HGSOC was 1.24×10-3 mm2/s. Conclusion: ADCmean derived from ADC histogram analysis provided quantitative information that allowed accurate differentiation of GCTs of the ovary, ovarian fibromas, and HGSOCs before surgery.

Epidemiological and virological surveillance of influenza viruses in China during 2020-2021.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, seasonal influenza activity declined globally and remained below previous seasonal levels, but intensified in China since 2021. Preventive measures to COVID-19 accompanied by different epidemic characteristics of influenza in different regions of the world. To better respond to influenza outbreaks under the COVID-19 pandemic, we analyzed the epidemiology, antigenic and genetic characteristics, and antiviral susceptibility of influenza viruses in the mainland of China during 2020-2021. METHODS: Respiratory specimens from influenza like illness cases were collected by sentinel hospitals and sent to network laboratories in Chinese National Influenza Surveillance Network. Antigenic mutation analysis of influenza virus isolates was performed by hemagglutination inhibition assay. Next-generation sequencing was used for genetic analyses. We also conducted molecular characterization and phylogenetic analysis of circulating influenza viruses. Viruses were tested for resistance to antiviral medications using phenotypic and/or sequence-based methods. RESULTS: In the mainland of China, influenza activity recovered in 2021 compared with that in 2020 and intensified during the traditional influenza winter season, but it did not exceed the peak in previous years. Almost all viruses isolated during the study period were of the B/Victoria lineage and were characterized by genetic diversity, with the subgroup 1A.3a.2 viruses currently predominated. 37.8% viruses tested were antigenically similar to reference viruses representing the components of the vaccine for the 2020-2021 and 2021-2022 Northern Hemisphere influenza seasons. In addition, China has a unique subgroup of 1A.3a.1 viruses. All viruses tested were sensitive to neuraminidase inhibitors and endonuclease inhibitors, except two B/Victoria lineage viruses identified to have reduced sensitivity to neuraminidase inhibitors. CONCLUSIONS: Influenza activity increased in the mainland of China in 2021, and caused flu season in the winter of 2021-2022. Although the diversity of influenza (sub)type decreases, B/Victoria lineage viruses show increased genetic and antigenic diversity. The world needs to be fully prepared for the co-epidemic of influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus globally.

Epidemiologic, Clinical, and Genetic Characteristics of Human Infections with Influenza A(H5N6) Viruses, China.

The recent rise in the frequency of influenza A(H5N6) infections in China has raised serious concerns about whether the risk for human infection has increased. We surveyed epidemiologic, clinical, and genetic data of human infections with A(H5N6) viruses. Severe disease occurred in 93.8% of cases, and the fatality rate was 55.4%. Median patient age was 51 years. Most H5N6 hemagglutinin (HA) genes in human isolates in 2021 originated from subclade 2.3.4.4b; we estimated the time to most recent common ancestor as June 16, 2020. A total of 13 genotypes with HA genes from multiple subclades in clade 2.3.4.4 were identified in human isolates. Of note, 4 new genotypes detected in 2021 were the major causes of increased H5N6 virus infections. Mammalian-adapted mutations were found in HA and internal genes. Although we found no evidence of human-to-human transmission, continuous evolution of H5N6 viruses may increase the risk for human infections.

Epidemiological and Virological Surveillance of Seasonal Influenza Viruses - China, 2020-2021.

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, the circulation of seasonal influenza virus declined globally and remained below previous seasonal levels. We analyzed the results of the epidemiology, antigenic, and genetic characteristics, and antiviral susceptibilities of seasonal influenza viruses isolated from the mainland of China during October 5, 2020 through September 5, 2021, to better assess the risk of influenza during subsequent influenza season in 2021-2022. METHODS: Positive rates of influenza virus detection during this period were based on real-time polymerase chain reaction (PCR) detection by the Chinese National Influenza Surveillance Network laboratories, and isolated viruses from influenza positive samples were submitted to the Chinese National Influenza Center. Antigenic analyses for influenza viruses were conducted using the hemagglutination inhibition assay. Next-generation sequencing was used for genetic analyses. Viruses were tested for resistance to antiviral medications using a phenotypic assay and next-generation sequencing. RESULTS: In southern China, the influenza positivity rate was elevated especially after March 2021 and was higher than the same period the previous year with the COVID-19 pandemic. In northern China, influenza positive rate peaked at Week 18 in 2021 and has declined since then. Nearly all isolated viruses were B/Victoria lineage viruses during the study period, and 37.3% of these viruses are antigenically similar to the reference viruses representing the vaccine components for the 2020-2021 and 2021-2022 Northern Hemisphere influenza season. All seasonal influenza viruses were susceptible to neuraminidase inhibitors and endonuclease inhibitors. CONCLUSIONS: Influenza activity has gradually increased in the mainland of China in 2021, although the intensity of activity is still lower than before the COVID-19 pandemic. The diversity of circulating influenza types/subtypes decreased, with the vast majority being B/Victoria lineage viruses. The surveillance data from this study suggest that we should strengthen influenza surveillance during the upcoming traditional influenza season. It also provided evidence for vaccine recommendations and prevention and control of influenza and clinical use of antiviral drugs.

Retrospective study of clinical characteristics and viral etiologies of patients with viral pneumonia in Beijing.

AIMS: The virus is common in patients with viral pneumonia. However, the viral etiology and clinical features of patients with viral pneumonia in China remain unclear. The main purpose of this study was to analyze the viral causes and epidemiology of patients with viral pneumonia in Beijing, which can significantly improve the pertinence and accuracy of clinical treatment of the disease. METHODS: Firstly, 1539 respiratory specimens of pneumonia (oropharyngeal swabs, nasopharyngeal swabs, saliva samples and bronchoalveolar lavage fluid) were collected from 19 hospitals in Beijing from September 2015 to August 2018. Then, TaqMan low-density microfluidic chip technology was used to detect viral pneumonia specimens in 1539 respiratory tract specimens of pneumonia and determine the types of viral bacteria in them. Lastly, the analysis of demographic, clinical and etiological data of patients with viral pneumonia was performed. RESULTS: The results showed that among the 1539 respiratory tract specimens with pneumonia, 760 were detected as viral pneumonia specimens, with a positive rate of 49.4%. Among which, 467 were infected with mono-viral and 293 were infected with multi-viral. Influenza A virus (Flu A), mycoplasma pneumoniae (MPn), Ebola virus (EBV) and herpes simplex virus type 1 (HSV-1) were the major viral components in the samples of these patients. Furthermore, these viral species were significantly associated with sample sources, onset season and certain clinical characteristics. DISCUSSION: Our findings may provide corresponding treatment strategies for viral pneumonia patients infected with specific viruses.

The relationship between non-alcoholic fatty liver disease and hypothyroidism: A systematic review and meta-analysis.

BACKGROUND: Whether hypothyroidism is related to non-alcoholic fatty liver disease (NAFLD) is controversial. Our aim was to investigate the relationship between NAFLD and hypothyroidism that may predict the NAFLD potential of these lesions and new prevention strategies in hypothyroidism patients. METHODS: Totally 51,407 hypothyroidism patients with average 28.23% NAFLD were analyzed by Revman 5.3 and Stata 15.1 softwares in the present study. The PubMed and Embase databases were systematically searched for works published through May 9, 2020. RESULTS: The blow variables were associated with an increased risk of NAFLD in hypothyroidism patients as following: increased of thyroid stimulating hormone (TSH) levels (odds ratio [OR] = 1.23, 1.07-1.39, P = .0001); old age (mean difference [MD] = 3.18, 1.57-4.78, P = .0001); increased of body mass index (BMI) (MD = 3.39, 2.79-3.99, P < .000001); decreased of free thyroxine 4 (FT4) levels (MD = -0.28, -0.53 to -0.03, P = .03). In addition, FT3 (MD = 0.11, -0.09-0.3, P = .29) had no association with the risk of NAFLD in hypothyroidism patients. CONCLUSION: Our systematic review identified results are as following: hypothyroidism was positively associated with the risk of NAFLD. The increased concentration of TSH levels maybe a risk factor that increased incidence of NAFLD. The BMI of NAFLD patients was significantly higher than that of non-NAFLD patients. Old age was significantly associated with the incidence of NAFLD. FT4 was significantly associated with the risk of NAFLD due to its negatively effect while FT3 was not significantly related to the risk of NAFLD. Taken together, the present meta-analysis provides strong evidence that hypothyroidism may play a vital role in the progression and the development of NAFLD.

Downregulation of metabotropic glutamate receptor 5 alleviates central sensitization by activating autophagy via inhibiting mTOR pathway in a rat model of chronic migraine.

Central sensitization is one of the important pathological mechanisms of chronic migraine (CM). Metabolic glutamate receptor 5 (mGluR5) mediates pain by activating various intracellular pathways. However, whether mGluR5 contributes to central sensitization in CM and the exact mechanism remains unclear. Male rats were used to establish a CM model by repeated infusions of inflammatory soup (IS) for 7 days to stimulate the activation of the dural nociceptor. The mechanical and thermal thresholds were used to evaluate allodynia, and central sensitization was assessed by measuring calcitonin gene-related peptide (CGRP) and substance P (SP). Microtubule associated protein 1 light chain 3 (LC3) and p62/SQSTM1 were used to assess autophagy. We found that the expression of mGluR5 in the trigeminal nucleus caudalis (TNC) of CM rats was significantly increased. In addition, the downregulation of mGluR5 activated autophagy by inhibiting the mTOR pathway. Moreover, the activation of autophagy alleviated allodynia and central sensitization in CM rats. This study identified a novel strategy for the treatment of CM; the downregulation of mGluR5 in a rat model of CM decreased the expression of the inflammatory factor interleukin-1 beta (IL-1ß) and the central sensitization-associated proteins CGRP and SP by activating autophagy via inhibiting the mTOR pathway.

Metabotropic glutamate receptor 5 regulates synaptic plasticity in a chronic migraine rat model through the PKC/NR2B signal.

BACKGROUND: The mechanism of chronic migraine (CM) is complex, central sensitization is considered as one of the pathological mechanism. Synaptic plasticity is the basis of central sensitization. Metabotropic glutamate receptor 5 (mGluR5) plays a vital role in the synaptic plasticity of the central nervous system. However, whether mGluR5 can promote the central sensitization by regulating synaptic plasticity in CM is unknown. METHODS: Male Wistar rats were used to establish a CM rat model, and the expression of mGluR5 mRNA and protein were detected by qRT-PCR and western blot. The allodynia was assessed by mechanical and thermal thresholds, and central sensitization was assessed by expression of the phosphorylation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) at Serine 133(pCREB-S133) and c-Fos. The synaptic-associated protein postsynaptic density protein 95 (PSD), synaptophysin (Syp), and synaptophysin-1(Syt-1), synaptic ultrastructure, and dendritic spines were detected to explore synaptic plasticity. The expression of PKC, total NR2B(tNR2B), and phosphorylation of NR2B at Tyr1472(pNR2B-Y1472) were detected by western blot. RESULTS: We found that the expression of mGluR5 was upregulated in CM rats. Downregulated the mGluR5 with MPEP alleviated the allodynia and reduced the expression of CGRP, pCREB-S133, c-Fos, PSD, Syp and Syt-1 and synaptic transmission. Moreover, the administration of MPEP inhibited the upregulation of PKC and pNR2B-Y1472. CONCLUSIONS: These results indicate that mGluR5 contributes to central sensitization by regulating synaptic plasticity in CM through the PKC/NR2B signal, which suggests that mGluR5 may be a potential therapeutic candidate for CM.

Deficiency in the function of inhibitory interneurons contributes to glutamate-associated central sensitization through GABABR2-SynCAM1 signaling in chronic migraine rats.

The occurrence of pain has always been closely related to a break in the balance between excitatory and inhibitory systems, and the internal relationship between these two systems has not been studied in the pathogenesis of chronic migraine (CM). In this study, we explored how inhibitory interneurons specifically modulate the glutamate-induced hyperexcitability in the periaqueductal gray (PAG) of CM rats. The CM model was established by repeated dural infusion of inflammatory soup (IS) in rats. Then, Baclofen, a gamma-aminobutyric acid type B receptor (GABABR) agonist; CGP35348, a GABABR antagonist; H89, a protein kinase A (PKA) inhibitor; and 8-Bromo-cAMP, a PKA agonist, were applied by intraventricular injection to investigate the detailed CM mechanism. Our results showed that GABABR2 mRNA and protein levels were significantly downregulated (P < .01) in the PAG of CM rats. Similarly, gamma-aminobutyric acid (GABA) and its synthetase glutamate decarboxylase 65/67 (GAD65/67) seriously decreased (P < .01), implying a deficit in the function of inhibitory interneurons in the PAG of CM rats. Afterward, the application of Baclofen and H89 alleviated the IS-evoked hyperalgesia and extenuated vesicular glutamate transporter 2 (VGLUT2), glutamate, calcitonin gene-related peptide (CGRP), and c-Fos expression by regulating the GABABR2/PKA/SynCAM1 pathway in the PAG of CM rats, while the application of CGP35348 and 8-Bromo-cAMP exactly exerted the opposite effect. Importantly, CGP35348 induced an elevation of CGRP, and VGLUT2 expression was relieved by H89. These data suggest that the loss in the function of inhibitory interneurons contributes to glutamate-associated central sensitization through the GABABR2/PKA/SynCAM1 pathway in the PAG of CM rats.

A Gene Constellation in Avian Influenza A (H7N9) Viruses May Have Facilitated the Fifth Wave Outbreak in China.

The 2016-2017 epidemic of influenza A (H7N9) virus in China prompted concern that a genetic change may underlie increased virulence. Based on an evolutionary analysis of H7N9 viruses from all five outbreak waves, we find that additional subclades of the H7 and N9 genes have emerged. Our analysis indicates that H7N9 viruses inherited NP genes from co-circulating H7N9 instead of H9N2 viruses. Genotypic diversity among H7N9 viruses increased following wave I, peaked during wave III, and rapidly deceased thereafter with minimal diversity in wave V, suggesting that the viruses entered a relatively stable evolutionary stage. The ZJ11 genotype caused the majority of human infections in wave V. We suggest that the largest outbreak of wave V may be due to a constellation of genes rather than a single mutation. Therefore, continuous surveillance is necessary to minimize the threat of H7N9 viruses.

Genesis and Spread of Newly Emerged Highly Pathogenic H7N9 Avian Viruses in Mainland China.

The novel low-pathogenic avian influenza A H7N9 viruses (LPAI H7N9 viruses) have been a threat to public health since their emergence in 2013 because of the high rates of mortality and morbidity that they cause. Recently, highly pathogenic variants of these avian influenza A H7N9 viruses (HPAI H7N9 viruses) have emerged and caused human infections and outbreaks among poultry in mainland China. However, it is still unclear how the HPAI H7N9 virus was generated and how it evolved and spread in China. Here, we show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region and spread southward to the Pearl River Delta region, possibly through live poultry trade. After introduction into the Pearl River Delta region, the origin LPAI H7N9 virus acquired four amino acid insertions in the hemagglutinin (HA) protein cleavage site and mutated into the HPAI H7N9 virus in late May 2016. Afterward, the HPAI H7N9 viruses further reassorted with LPAI H7N9 or H9N2 viruses locally and generated multiple different genotypes. As of 14 July 2017, the HPAI H7N9 viruses had spread from Guangdong Province to at least 12 other provinces. The rapid geographical expansion and genetic evolution of the HPAI H7N9 viruses pose a great challenge not only to public health but also to poultry production. Effective control measures, including enhanced surveillance, are therefore urgently needed.IMPORTANCE The LPAI H7N9 virus has caused five outbreak waves in humans and was recently reported to have mutated into highly pathogenic variants. It is unknown how the HPAI H7N9 virus originated, evolved, and disseminated in China. In this study, we comprehensively analyzed the sequences of HPAI H7N9 viruses from 28 human and 21 environmental samples covering eight provinces in China that were taken from November 2016 to June 2017. The results show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region. However, the insertion of four amino acids into the HA protein cleavage site of an LPAI H7N9 virus occurred in late May 2016 in the Pearl River Delta region. The mutated HPAI H7N9 virus further reassorted with LPAI H7N9 or H9N2 viruses that were cocirculating in poultry. Considering the rapid geographical expansion of the HPAI H7N9 viruses, effective control measures are urgently needed.