A Distinct Gene Module for Dysfunction Uncoupled from Activation in Tumor-Infiltrating T Cells.

Reversing the dysfunctional T cell state that arises in cancer and chronic viral infections is the focus of therapeutic interventions; however, current therapies are effective in only some patients and some tumor types. To gain a deeper molecular understanding of the dysfunctional T cell state, we analyzed population and single-cell RNA profiles of CD8(+) tumor-infiltrating lymphocytes (TILs) and used genetic perturbations to identify a distinct gene module for T cell dysfunction that can be uncoupled from T cell activation. This distinct dysfunction module is downstream of intracellular metallothioneins that regulate zinc metabolism and can be identified at single-cell resolution. We further identify Gata-3, a zinc-finger transcription factor in the dysfunctional module, as a regulator of dysfunction, and we use CRISPR-Cas9 genome editing to show that it drives a dysfunctional phenotype in CD8(+) TILs. Our results open novel avenues for targeting dysfunctional T cell states while leaving activation programs intact.

Endogenous Glucocorticoid Signaling Regulates CD8+ T Cell Differentiation and Development of Dysfunction in the Tumor Microenvironment.

Identifying signals in the tumor microenvironment (TME) that shape CD8+ T cell phenotype can inform novel therapeutic approaches for cancer. Here, we identified a gradient of increasing glucocorticoid receptor (GR) expression and signaling from naïve to dysfunctional CD8+ tumor-infiltrating lymphocytes (TILs). Conditional deletion of the GR in CD8+ TILs improved effector differentiation, reduced expression of the transcription factor TCF-1, and inhibited the dysfunctional phenotype, culminating in tumor growth inhibition. GR signaling transactivated the expression of multiple checkpoint receptors and promoted the induction of dysfunction-associated genes upon T cell activation. In the TME, monocyte-macrophage lineage cells produced glucocorticoids and genetic ablation of steroidogenesis in these cells as well as localized pharmacologic inhibition of glucocorticoid biosynthesis improved tumor growth control. Active glucocorticoid signaling associated with failure to respond to checkpoint blockade in both preclinical models and melanoma patients. Thus, endogenous steroid hormone signaling in CD8+ TILs promotes dysfunction, with important implications for cancer immunotherapy.

Checkpoint Blockade Immunotherapy Induces Dynamic Changes in PD-1-CD8+ Tumor-Infiltrating T Cells.

An improved understanding of the anti-tumor CD8+ T cell response after checkpoint blockade would enable more informed and effective therapeutic strategies. Here we examined the dynamics of the effector response of CD8+ tumor-infiltrating lymphocytes (TILs) after checkpoint blockade therapy. Bulk and single-cell RNA profiles of CD8+ TILs after combined Tim-3+PD-1 blockade in preclinical models revealed significant changes in the transcriptional profile of PD-1- TILs. These cells could be divided into subsets bearing characterstics of naive-, effector-, and memory-precursor-like cells. Effector- and memory-precursor-like TILs contained tumor-antigen-specific cells, exhibited proliferative and effector capacity, and expanded in response to different checkpoint blockade therapies across different tumor models. The memory-precursor-like subset shared features with CD8+ T cells associated with response to checkpoint blockade in patients and was compromised in the absence of Tcf7. Expression of Tcf7/Tcf1 was requisite for the efficacy of diverse immunotherapies, highlighting the importance of this transcriptional regulator in the development of effective CD8+ T cell responses upon immunotherapy.

Treg cells expressing the coinhibitory molecule TIGIT selectively inhibit proinflammatory Th1 and Th17 cell responses.

Foxp3(+) T regulatory (Treg) cells regulate immune responses and maintain self-tolerance. Recent work shows that Treg cells are comprised of many subpopulations with specialized regulatory functions. Here we identified Foxp3(+) T cells expressing the coinhibitory molecule TIGIT as a distinct Treg cell subset that specifically suppresses proinflammatory T helper 1 (Th1) and Th17 cell, but not Th2 cell responses. Transcriptional profiling characterized TIGIT(+) Treg cells as an activated Treg cell subset with high expression of Treg signature genes. Ligation of TIGIT on Treg cells induced expression of the effector molecule fibrinogen-like protein 2 (Fgl2), which promoted Treg-cell-mediated suppression of T effector cell proliferation. In addition, Fgl2 was necessary to prevent suppression of Th2 cytokine production in a model of allergic airway inflammation. TIGIT expression therefore identifies a Treg cell subset that demonstrates selectivity for suppression of Th1 and Th17 cell but not Th2 cell responses.

[Characteristics and Source Apportionment of Black Carbon Over the Eastern Tibetan Plateau].

As the most important absorbing aerosol, black carbon (BC) can affect radiation, clouds, and surface snow cover over the Tibetan Plateau. In this study, the BC mass concentrations were measured using a seven-channel aethalometer (AE-33) in Litang County over the eastern Tibetan Plateau from July 5 to September 5, 2017. The aethalometer model, potential source contribution function (PSCF), and concentration-weighted trajectory (CWT) models were used to analyze the variation characteristics, potential sources, and affecting areas of BC. The results showed that the mass concentration of ρ(BC) in Litang ranged from 0.4 to 4699.8 ng·m-3, with an average value of 816.4 ng·m-3, accounting for 5.96% of PM2.5. The average mass concentrations of ρ(BCliquid) and ρ(BCsolid) in Litang were 486.1 ng·m-3 and 398.5 ng·m-3, respectively, with a C of 0.51. The ρ(BC) mass concentration was mainly distributed from 0-2000 ng·m-3, which accounted for 92.5% of the total observation period. The diurnal variation in BC, BCliquid, and BCsolid showed a bimodal distribution, with the peaks appearing at 08:00 and 20:00, respectively. The first peak was mainly related to traffic sources and incomplete combustion of carbonaceous materials, whereas the second peak was mainly related to incomplete combustion of carbonaceous materials. The potential sources and affecting areas of PM2.5 and BC were different. Imports from abroad had a greater impact on the concentrations of PM2.5 and BC in Litang, and the affecting areas were mainly transmitted to the northeast in China. The high-value centers were mainly concentrated in the surrounding areas of Litang.

Tim-3 adapter protein Bat3 acts as an endogenous regulator of tolerogenic dendritic cell function.

Dendritic cells (DCs) sense environmental cues and adopt either an immune-stimulatory or regulatory phenotype, thereby fine-tuning immune responses. Identifying endogenous regulators that determine DC function can thus inform the development of therapeutic strategies for modulating the immune response in different disease contexts. Tim-3 plays an important role in regulating immune responses by inhibiting the activation status and the T cell priming ability of DC in the setting of cancer. Bat3 is an adaptor protein that binds to the tail of Tim-3; therefore, we studied its role in regulating the functional status of DCs. In murine models of autoimmunity (experimental autoimmune encephalomyelitis) and cancer (MC38-OVA-implanted tumor), lack of Bat3 expression in DCs alters the T cell compartment-it decreases TH1, TH17 and cytotoxic effector cells, increases regulatory T cells, and exhausted CD8+ tumor-infiltrating lymphocytes, resulting in the attenuation of autoimmunity and acceleration of tumor growth. We found that Bat3 expression levels were differentially regulated by activating versus inhibitory stimuli in DCs, indicating a role for Bat3 in the functional calibration of DC phenotypes. Mechanistically, loss of Bat3 in DCs led to hyperactive unfolded protein response and redirected acetyl-coenzyme A to increase cell intrinsic steroidogenesis. The enhanced steroidogenesis in Bat3-deficient DC suppressed T cell response in a paracrine manner. Our findings identified Bat3 as an endogenous regulator of DC function, which has implications for DC-based immunotherapies.

Nocturnal surface radiation cooling modulated by cloud cover change reinforces PM2.5 accumulation: Observational study of heavy air pollution in the Sichuan Basin, Southwest China.

Surface radiation is crucial to atmospheric boundary layer development and air pollution formation. Several studies have revealed that surface radiation plays a vital role in developing the daytime convective boundary layer that controls the explosive growth of PM2.5 concentration; however, less attention has been paid to the effects of changing nighttime surface radiation on the near-surface temperature inversion layer and PM2.5 accumulation. In this study, we used long-term observations of meteorological and environmental data and atmospheric boundary layer measurements during a severe PM2.5 pollution event to investigate the effect of changes in nocturnal surface radiation on the increase in PM2.5 concentrations. The results showed that surface radiation cooling was enhanced (weakened) by decreased (increased) cloud cover fraction by changing longwave radiation at night; this strengthened (weakened) near-surface temperature inversion intensity and promoted (prevented) the accumulated increase in PM2.5. This observational study using 5-year data further confirmed the cloud radiative effect on the nighttime accumulation of PM2.5 with a significant negative correlation between nighttime averages of surface PM2.5 concentrations and cloud cover fractions. This reveals an important mechanism for the impact of surface radiation cooling modulated by cloud cover change on the nighttime accumulated increase in PM2.5. This finding extends our understanding of air pollutant accumulation at night with potential implications for atmospheric environment change.

An IL-27-Driven Transcriptional Network Identifies Regulators of IL-10 Expression across T Helper Cell Subsets.

Interleukin-27 (IL-27) is an immunoregulatory cytokine that suppresses inflammation through multiple mechanisms, including induction of IL-10, but the transcriptional network mediating its diverse functions remains unclear. Combining temporal RNA profiling with computational algorithms, we predict 79 transcription factors induced by IL-27 in T cells. We validate 11 known and discover 5 positive (Cebpb, Fosl2, Tbx21, Hlx, and Atf3) and 2 negative (Irf9 and Irf8) Il10 regulators, generating an experimentally refined regulatory network for Il10. We report two central regulators, Prdm1 and Maf, that cooperatively drive the expression of signature genes induced by IL-27 in type 1 regulatory T cells, mediate IL-10 expression in all T helper cells, and determine the regulatory phenotype of colonic Foxp3+ regulatory T cells. Prdm1/Maf double-knockout mice develop spontaneous colitis, phenocopying ll10-deficient mice. Our work provides insights into IL-27-driven transcriptional networks and identifies two shared Il10 regulators that orchestrate immunoregulatory programs across T helper cell subsets.

[Analysis of Pollution Characteristics and Sources of PM2.5 Chemical Components in Chengdu in Winter].

Day-night PM2.5 samples were continuously collected in Chengdu from January 1 to 20, 2017, and the concentrations of major chemical components (water-soluble ions and carbonaceous components) were measured in the laboratory. During the observation period, the average mass concentration of PM2.5 was (127.1±59.9) µg·m-3. The mass concentration of water-soluble ions was (56.5±25.7) µg·m-3 and SO42-, NO3-, and NH4+ were the most dominant ions with a concentration of (13.6±5.5), (21.4±12.0), and (13.3±5.7) µg·m-3, respectively, accounting for 85.6% of the water-soluble ions. The average mass concentrations of organic carbon (OC) and elemental carbon (EC) were 34.0 and 6.1 µg·m-3, respectively, accounting for 26.8% and 4.8% of the PM2.5 mass concentration, respectively. The comparison of the average day-night concentration shows that the daytime and nighttime mass concentrations of PM2.5 are (120.4±56.4) and (133.8±64.0) µg·m-3, respectively, and that the nighttime pollution is more serious. The SO42-, NO3-, and NH4+ concentrations are higher during the day than at night, which is related to daytime light, which promotes the formation of secondary ions. The Cl-, K+, OC, and EC concentrations increase significantly, which may be affected by increased emissions from coal and material combustion. Based on the literature review and comparison of the winter chemical composition of PM2.5 in Chengdu in recent years, the SO42- concentration significantly decreases from 50.6 µg·m-3 in 2010 to 13.6 µg·m-3 in 2017. The NO3- concentration changes little; it is maintained at~20 µg·m-3. The analysis of the acid-alkali ion balance shows that PM2.5 in Chengdu is alkaline due to the relative overgrowth of NH4+, which is different from previous partially acidic results. The average value of NO3-/SO42- is 1.57. Mobile sources have a greater impact on the PM2.5 pollution in Chengdu in winter. The correlation coefficients of OC and EC between daytime and nighttime are 0.82 and 0.90, respectively (P<0.01), which indicates that the OC and EC sources are consistent. The SOC estimation shows that the SOC concentrations during the day and night are 8.5 µg·m-3 and 11.9 µg·m-3, respectively, accounting for 28.1% and 30.8% of the OC, respectively. The K+/EC average value is 0.31 and the correlation coefficient between K+ and OC is 0.87 (P<0.01), indicating that biomass combustion has a certain influence on the carbonaceous aerosol in Chengdu in winter. The principal component analysis shows that the winter PM2.5 in Chengdu mainly originates from combustion sources (coal burning, biomass burning, etc.), secondary inorganic sources, and soil and dust sources. The contribution rates are 32.8%, 34.5%, and 21.5%, respectively.

[Pollution Characteristics and Light Extinction Contribution of Water-soluble Ions of PM2.5 in Hangzhou].

The pollution characteristics and light extinction contribution of water-soluble ions of PM2.5 in Hangzhou were investigated by sampling and laboratory analysis of aerosol samplers in 2013. The water-soluble ions were dominant in PM2.5 and the total mass concentration was 37.5 µg·m-3, accounting for 44.4% of the PM2.5 mass concentration. Water-soluble ions were mainly composed of secondary ions(SO42-,NO3- and NH4+), which accounted for 83.4% of total ions. The highest mass concentrations of PM2.5 and major ions were observed in winter and the lowest in summer. The proportions of water-soluble ions in PM2.5 in summer and autumn were obviously higher than those in winter and spring and proportions of secondary ions in water-soluble ions were very close in each season. The contribution was the greatest to PM2.5 from secondary ions generation caused by fuel combustion and automobile exhaust. The annual average values of SOR and NOR were 0.27 and 0.15 respectively, the conversion rate of SO2 in atmosphere was greater than that of NOx. There was obvious positive correlation between SOR or NOR and humidity which indicated the important contribution of heterogeneous oxidation process to the generation of SO42- and NO3-. The annual average of[NO3-]/[SO42-] was 0.63, and the aerosol pollution was primarily affected by emissions from coal burning. In haze days, with the increase of haze pollution level, the mass concentrations of PM2.5, water-soluble ions, secondary ions as well as SOR and NOR all increased gradually, and the stable weather condition in haze days could efficiently promote the accumulation and secondary conversion of pollutants. There were obvious positive correlations between mass concentrations of PM2.5 and SNA and the atmospheric light extinction coefficient. The IMPROVE formula which was used to calculate the light extinction coefficients of different chemical components could efficiently indicate the tendency of aerosol scattering. The extinction contribution of SNA could reach 60.8%. The extinction coefficient of SNA was the highest in winter and lowest in summer, and its value and contribution proportion both increased gradually as the haze pollution level rose.

[Pollution Characteristics of Aerosol Number Concentration in Winter and Spring in a Northern Suburb of Nanjing].

Using APS-3321, the atmospheric aerosol number concentrations (0.5-20 µm) were continuously monitored to analyze the characteristics of winter and spring pollution in 2014 in a northern suburb of Nanjing. The average number concentrations were (364.8±297.8) cm-3 and (79.6±62.4) cm-3 in winter and spring, respectively; fine particles (0.5-1.0 µm) accounted for 87.8% and 86.6% of the total, respectively. There were significant variations in number concentration at different periods. The diurnal variations in number concentrations were evident with high concentrations at night and low concentrations during the day. The early peaks were at 07:00 and 09:00, and number concentrations began to increase rapidly starting at 17:00 and 18:00 in winter and spring, respectively. The distribution of the number concentrations was unimodal, with peak sizes between 0.583 and 0.626 µm in winter and less than 0.542 µm in spring. With the increase in relative humidity, aerosol number concentrations increased gradually; at the same time, the peak size moved to a larger diameter which reflected the influence of hygroscopic growth of aerosols. During the total observation period, it reached 83.3% of the proportion of hazy days. The number concentration of particles less than 2.0 µm increased significantly with the increase in the haze pollution level, which was more obvious in winter. In spring, the proportion of fine particles increased with the increase in the haze level but in winter, it decreased during hazy days due to a significant increase in particle size caused by aging. The analysis of the typical pollution process in January indicated that there was a strong correlation between the source of air mass and the surface wind direction. Pollutants transmitted from the northern Jiangsu Province and the accumulation of pollutants due to slow winds were important causations of the pollution process.

[Variation of Size Distribution and the Influencing Factors of Aerosol in Northern Suburbs of Nanjing].

The size distribution of particulate was analyzed by the FA-3 9 stage sampler in Northern-suburb of Nanjing from January to November in 2014. First, the monitoring result from FA-3 was compared with the results of the same period obtained from a medium flow size grading sampler (KC-120H) and online monitoring instrument of the Environmental Protection Agency. The data correlation coefficients were all greater than 0.95. The fine particle concentration from FA-3 was lower by 13.9% and 16.6%, while PM10 concentration was higher by 15.2% and 13.3% respectively. However, the deviations were in the acceptable range of atmospheric sampling which could indicate the accurate classification and sampling of particulate for FA-3. Particulate pollution in Northern-suburb Nanjing was serous in which the annual average concentrations of PM1.1, PM2.1 and PM10 were(65.6±37.6), (91.0±54.7) and (168.0±87.0) µg·m-3 respectively; fine particles dominated and most of them had a diameter of less than 1.1 µm. Particle size distribution was bimodal with peaks at 0.43-0.65 and 9-10 µm; the median diameter was 1.83 µm which was in the accumulation mode. In winter, the concentration of fine particle size was higher and in spring the coarse particle size was higher; in summer, the fine particle size concentration was not significantly reduced but coarse particle size was obviously lower than those in other seasons. The differences of particle size distribution in day and at night were very small in coarse segment and in fine segment, the nocturnal concentrations were mostly higher than diurnal concentrations. The precipitation had cleaning effect for each size range of particulate except in summer and the effect was more distinct in fine particle size. In haze days, with the aggravation of haze level, the particle concentration in the diameter range of 0.43-2.1 µm increased gradually while in this segment the particle concentration was significantly negatively correlated with visibility. Using relative humidity of 70% as the demarcation, the particle size distribution changed significantly:when humidity was greater than 70%, mass concentration of particle with a diameter of less than 0.43 µm reduced significantly but that with diameter range of 0.43-2.1 µm increased obviously which should be related to the particle hygroscopic growth. The air mass sources could be divided into four categories in northern-suburb of Nanjing. Air mass from the northwest with rapid transport velocity was the cleanest in which the fine particle size concentration was significantly lower than those in other directions; the air mass from local and surrounding was the most severely polluted with high concentrations in both fine and coarse segment, its transmission distance was short and wind speed was small which contributed greatly to air pollution of Nanjing with probability of occurrence of pollution reaching 73.9%.