Endosomal TLRs (TLR3/7/8/9) are highly analogous innate immunity sensors for various viral or bacterial RNA/DNA molecular patterns. Among them, TLR7, in particular, has been suggested to be a target for various inflammatory disorders and autoimmune diseases including systemic lupus erythematosus (SLE); but few small-molecule inhibitors with elaborated mechanism have been reported in literature. Here, we reported a well-characterized human TLR7-specific small-molecule inhibitor, TH-407b, with promising potency and negligible cytotoxicity through a novel binding mechanism. Notably, TH-407b not only effectively inhibited TLR7-mediated pro-inflammatory signaling in a variety of cultured cell lines but also demonstrated potent inflammation suppressing activities in primary peripheral blood mononuclear cells (PBMCs) derived from SLE patients. Furthermore, TH-407b showed prominent efficacy in vivo, improved survival rate and ameliorated symptoms of SLE model mice. To obtain molecular insights into the TH-407b derivatives' inhibition mechanism, we performed the structural analysis of TLR7/TH-407b complex using cryogenic electron microscopy (cryo-EM) method. As an atomistic resolution cryo-EM structure of the TLR family, it not only of value to facilitate structure-based drug design, but also shed light to methodology development of small proteins using EM. Significantly, TH-407b has unveiled an inhibition strategy for TLR7 via stabilizing its resting/inactivated state. Such a resting state could be generally applicable to all TLRs, rendering a useful method for targeting this group of important immunological receptors.

Objective:To analyze HIV testing behaviors and associated factors in men who have sex with men (MSM) and provide evidence for making intervention on promoting HIV testing.Methods:Our observational study was conducted between April and June, 2018 in Wuxi, Jiangsu province in MSM. A self-completed questionnaire was used to collect the information about their socio-demographic characteristics, sexual behaviors, acceptance of intervention services, psychological status and HIV testing behaviors. Structural equation model (SEM) was chosen to fit data and the model was modified to analyze the relationships between variables.Results:A total of 410 MSM were enrolled in our study, among whom 72.9%(299/410) were aware of the necessity of HIV testing and 69.0%(283/410) reported having HIV tests in the last year. A modified structural equation model presented good fitting results with fitting index of root mean square error of approximation (RMSEA)was 0.065, normed fit index (NFI) was 0.946, relative fit index (RFI) was 0.922, Tucker-Lewis index (TLI) was 0.968 and comparative fit index (CFI) was 0.952. Results of SEM showed that intervention service was the factor with the largest standardized total effect value of 0.57 associated with HIV testing behaviors among MSM. Among intervention services, HIV testing reminding had the biggest factor loading of 0.88. Psychological status scores played a negative role in HIV testing behaviors among MSM with the path coefficient value of -0.33.Conclusions:The awareness and testing rate of HIV among MSM population need to be further improved. While effective measures are implemented to promote HIV testing among MSM, more attention should be paid to the mental health problems of MSM.

Objective:This study aimed to discover the HIV infection and associated factors among male sex workers (MSW) who provide sexual services for men. Data from this study thus can be used to provide evidence for designing related intervention programs.Methods:In this observational study, MSW were recruited from May to July, 2019 in KTV venues in Wuxi, China. A questionnaire was used to collect information with blood sample collected and tested for HIV and syphilis. EpiData 3.0 and SPSS 17.0 software were used to clean up data and statistical analysis.Results:A number of 500 MSW were involved including 243 (48.6 %) heterosexual and 257 (51.4 %) homosexual MSW. The overall HIV prevalence was 5.4 %(27/500) among all the MSW. there were significant differences between the HIV prevalence rates, the heterosexual MSW (3.3 %, 8/243) and the homosexual MSW (7.4 %, 19/257)( χ2=4.112, P=0.043). In the past 3 months, 28.0 % (72/257) of the homosexual MSW mainly engaged in receptive anal sex which was higher than 11.5 %(28/243) of the heterosexual MSW. Compared to 15.6 % (40/257) of the homosexual MSW who engaged in heterosexual behavior, a higher proportion of 98.4 % (239/243) was noticed among the heterosexual MSW. Higher percentage (44.9 %, 109/243) appeared among the heterosexual MSW who had not been tested for HIV than the homosexual MSW (20.6 %, 53/257). Results from logistic regression multivariate analysis showed that age ≥30 (a OR=7.54, 95 %CI: 2.53-37.11), having unprotected anal sexual practice (a OR=3.76, 95 %CI:1.15-12.23), having anal sex after drinking alcohol (a OR=10.91, 95 %CI: 2.29-51.87) and syphilis tested positive (a OR=8.23, 95 %CI:1.29-52.51) were risk factors associated with HIV infection among the heterosexual MSW. Having unprotected anal sexual behavior (a OR=2.94, 95 %CI: 1.17-7.37), having group anal sex (a OR=4.08, 95 %CI:1.05-15.81), without record on HIV testing (a OR=6.58, 95 %CI: 2.01-18.06) and syphilis tested positive (a OR=4.55, 95 %CI: 1.15-18.06) were risk factors associated with HIV among the homosexual MSW. Conclusions:High HIV prevalence was discovered among both heterosexual and homosexual MSW in Wuxi, China. Differences in sexual behaviors between these two groups should be considered when designing targeted HIV intervention programs for these populations.

Objective To investigate effects of polyphylin Ⅰ on the proliferation and apoptosis of human melanoma cell line A375,and to explore their mechanisms.Methods Normal human melanocytes isolated from healthy human foreskin were divided into 6 groups to be treated with 0,1.5,3.0,6.0,9.0,12.0 mg/L polyphyllin Ⅰ respectively.A375 melanoma cells were divided into 4 groups,i.e.,control group,1.5-,3.0-,6.0-mg/L polyphyllin Ⅰ groups,to be treated with 0,1.5,3.0,6.0 mg/L polyphyllin Ⅰ,respectively.Cell counting kit-8 (CCK8) assay was performed to evaluate the effect of polyphyllin Ⅰ on the proliferation of normal human melanocytes and A375 cells.Hoechst 33258 fluorescent staining was conducted to observe the morphology of apoptotic cells,flow cytometry to estimate cell cycle phase distribution and apoptosis rate,dichloro-dihydro-fluorescein diacetate (DCFH-DA) fluorescent probe assay to detect the level of reactive oxygen species (ROS),rhodamine-123 staining to evaluate changes of mitochondrial membrane potential,spectrophotography to detect the level of ATP in A375 cells,as well as levels of lactic acid and glucose in the culture supernatant of A375 cells,and Western blot analysis to determine the protein expression of Bcl-2,Bcl-2-related X protein (Bax),cleaved-caspase-3,cyclin D1 and pyruvate kinase isozyme type M2 (PKM2).Statistical analysis was carried out by using one-way analysis of variance (ANOVA) for comparisons among groups and Student-Newman-Keuls-q (SNK-q) test for multiple comparisons.Results CCK8 assay showed that the treatment with polyphyllin Ⅰ at concentrations of 1.5,3.0,6.0 mg/L for 48 hours had no effects on the proliferation of normal human melanocytes,but significantly inhibited the proliferation of A375 cells.The survival rate of A375 cells was significantly lower in the 1.5-,3.0-,6.0-mg/L polyphyllin Ⅰ groups than in the control group (P ＜ 0.01).After the treatment with polyphyllin Ⅰ,distinct apoptotic morphology of A375 cells was observed under fluorescence microscope.Additionally,along with the increase of polyphyllin Ⅰ concentrations (0,1.5,3.0,6.0 mg/L),there were gradual increasing trends in the apoptosis rate of A375 cells (4.25％ ± 1.27％,10.03％ ± 1.49％,36.62％ ± 1.97％,44.11％ ± 2.47％ respectively,F =665.7,P ＜ 0.01),the percentage of A375 cells at G0/G1 phase (54.13％ ± 2.57％,67.35％ ± 3.79％,74.39％ ± 3.29％,82.29％ ± 3.99％ respectively,F =71.81,P ＜ 0.01),the level of ROS in A375 cells (P ＜ 0.01),the level of glucose in the culture supernatant (P ＜ 0.01),and the protein expression of Bax and cleaved-caspase-3 (both P ＜ 0.01),while gradual decreasing trends were found in the levels of mitochondrial membrane potential and ATP in A375 cells (both P ＜ 0.01),the level of lactic acid in the culture supernatant (P ＜ 0.01),and the protein expression of Cyclin D1,Bcl-2 and PKM2 (all P ＜ 0.01).Conclusion Polyphyllin Ⅰ can effectively induce A375 cell apoptosis by promoting the production of ROS in A375 cells and decreasing the mitochondrial membrane potential,and arrest A375 cells at G0/G1 phase by inhibiting the expression of PKM2 and Cyclin D1.