Integrated Analysis of Ferroptosis and Immunity-Related Genes Associated with Diabetic Kidney Disease.

Purpose: Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease (CKD) worldwide. Elucidation of the molecular mechanisms underlying ferroptosis and immunity in DKD could aid the development of potentially effective therapeutics. This study aimed to perform an integrated analysis of ferroptosis and immune-related differentially expressed mRNAs (DEGs) in DKD. Materials and Methods: Gene expression profiles of samples obtained from patients with DKD and controls were downloaded from the Gene Expression Omnibus (GEO) database. The potential differentially expressed genes (DEGs) were screened using R software, and ferroptosis immune-related differentially expressed genes (FIRDEGs) were extracted from the DEGs. We performed functional enrichment analyses, and constructed protein-protein interaction (PPI) networks, transcription factor (TFs)-gene networks, and gene-drug networks to explore their potential biological functions. Correlation analysis and receiver operating characteristic curves were used for evaluating the FIRDEGs. We used the CIBERSORT algorithm to examine the composition of immune cells and determine the relationship between FIRDEG signatures and immune cells. Finally, the RNA expression of six FIRDEGs was validated in animal kidney samples using RT-PCR. Results: We identified 80 FIRDEGs and performed their functional analyses. We identified six hub genes (Ccl5, Il18, Cybb, Fcgr2b, Myd88, and Ccr2) using PPI networks and predicted potential TF gene networks and gene-drug pairs. Immune cells, including M2 macrophages, resting mast cells, and gamma-delta T cells, were altered in DKD; the FIRDEGs (Fcgr2b, Cybb, Ccr2, and Ccl5) were closely correlated with the infiltration abundance of M2 macrophages and gamma-delta T cells. Finally, the hub genes were verified in mouse kidney samples. Conclusion: We identified six hub FIRDEGs (Ccl5, Il18, Cybb, Fcgr2b, Myd88, and Ccr2) in DKD, and predicted the potential transcription factor gene networks and possible treatment targets for future research.

Vegetation structural shift tells environmental changes on the Tibetan Plateau over 40 years.

Structural information of grassland changes on the Tibetan Plateau is essential for understanding alterations in critical ecosystem functioning and their underlying drivers that may reflect environmental changes. However, such information at the regional scale is still lacking due to methodological limitations. Beyond remote sensing indicators only recognizing vegetation productivity, we utilized multivariate data fusion and deep learning to characterize formation-based plant community structure in alpine grasslands at the regional scale of the Tibetan Plateau for the first time and compared it with the earlier version of Vegetation Map of China for historical changes. Over the past 40 years, we revealed that (1) the proportion of alpine meadows in alpine grasslands increased from 50% to 69%, well-reflecting the warming and wetting trend; (2) dominances of Kobresia pygmaea and Stipa purpurea formations in alpine meadows and steppes were strengthened to 76% and 92%, respectively; (3) the climate factor mainly drove the distribution of Stipa purpurea formation, but not the recent distribution of Kobresia pygmaea formation that was likely shaped by human activities. Therefore, the underlying mechanisms of grassland changes over the past 40 years were considered to be formation dependent. Overall, the first exploration for structural information of plant community changes in this study not only provides a new perspective to understand drivers of grassland changes and their spatial heterogeneity at the regional scale of the Tibetan Plateau, but also innovates large-scale vegetation study paradigm.

Plant Community Associates with Rare Rather than Abundant Fungal Taxa in Alpine Grassland Soils.

The importance of the rare microbial biosphere in maintaining biodiversity and ecological functions has been highlighted recently. However, the current understanding of the spatial distribution of rare microbial taxa is still limited, with only a few investigations for rare prokaryotes and virtually none for rare fungi. Here, we investigated the spatial patterns of rare and abundant fungal taxa in alpine grassland soils across 2,000 km of the Qinghai-Tibetan plateau. We found that most locally rare fungal taxa remained rare (13.07%) or were absent (82.85%) in other sites, whereas only a small proportion (4.06%) shifted between rare and abundant among sites. Although they differed in terms of diversity levels and compositions, the distance decay relationships of both the rare and the abundant fungal taxa were valid and displayed similar turnover rates. Moreover, the community assemblies of both rare and abundant fungal taxa were predominantly controlled by deterministic rather than stochastic processes. Notably, the community composition of rare rather than abundant fungal taxa associated with the plant community composition. In summary, this study advances our understanding of the biogeographic features of rare fungal taxa in alpine grasslands and highlights the concordance between plant communities and rare fungal subcommunities in soil. IMPORTANCE Our current understanding of the ecology and functions of rare microbial taxa largely relies on research conducted on prokaryotes. Despite the key ecological roles of soil fungi, little is known about the biogeographic patterns and drivers of rare and abundant fungi in soils. In this study, we investigated the spatial patterns of rare and abundant fungal taxa in Qinghai-Tibetan plateau (QTP) alpine grassland soils across 2,000 km, with a special concentration on the importance of the plant communities in shaping rare fungal taxa. We showed that rare fungal taxa generally had a biogeographic pattern that was similar to that of abundant fungal taxa in alpine grassland soils on the QTP. Furthermore, the plant community composition was strongly related to the community composition of rare taxa but not abundant taxa. In summary, this study significantly increases our biogeographic and ecological knowledge of rare fungal taxa in alpine grassland soils.

Soil diazotrophic abundance, diversity, and community assembly mechanisms significantly differ between glacier riparian wetlands and their adjacent alpine meadows.

Global warming can trigger dramatic glacier area shrinkage and change the flux of glacial runoff, leading to the expansion and subsequent retreat of riparian wetlands. This elicits the interconversion of riparian wetlands and their adjacent ecosystems (e.g., alpine meadows), probably significantly impacting ecosystem nitrogen input by changing soil diazotrophic communities. However, the soil diazotrophic community differences between glacial riparian wetlands and their adjacent ecosystems remain largely unexplored. Here, soils were collected from riparian wetlands and their adjacent alpine meadows at six locations from glacier foreland to lake mouth along a typical Tibetan glacial river in the Namtso watershed. The abundance and diversity of soil diazotrophs were determined by real-time PCR and amplicon sequencing based on nifH gene. The soil diazotrophic community assembly mechanisms were analyzed via iCAMP, a recently developed null model-based method. The results showed that compared with the riparian wetlands, the abundance and diversity of the diazotrophs in the alpine meadow soils significantly decreased. The soil diazotrophic community profiles also significantly differed between the riparian wetlands and alpine meadows. For example, compared with the alpine meadows, the relative abundance of chemoheterotrophic and sulfate-respiration diazotrophs was significantly higher in the riparian wetland soils. In contrast, the diazotrophs related to ureolysis, photoautotrophy, and denitrification were significantly enriched in the alpine meadow soils. The iCAMP analysis showed that the assembly of soil diazotrophic community was mainly controlled by drift and dispersal limitation. Compared with the riparian wetlands, the assembly of the alpine meadow soil diazotrophic community was more affected by dispersal limitation and homogeneous selection. These findings suggest that the conversion of riparian wetlands and alpine meadows can significantly alter soil diazotrophic community and probably the ecosystem nitrogen input mechanisms, highlighting the enormous effects of climate change on alpine ecosystems.

Unimodal productivity-biodiversity relationship along the gradient of multidimensional resources across Chinese grasslands.

Resources can affect plant productivity and biodiversity simultaneously and thus are key drivers of their relationships in addition to plant-plant interactions. However, most previous studies only focused on a single resource while neglecting the nature of resource multidimensionality. Here we integrated four essential resources for plant growth into a single metric of resource diversity (RD) to investigate its effects on the productivity-biodiversity relationship (PBR) across Chinese grasslands. Results showed that habitats differing in RD have different PBRs-positive in low-resource habitats, but neutral in medium- and high-resource ones-while collectively, a weak positive PBR was observed. However, when excluding direct effects of RD on productivity and biodiversity, the PBR in high-resource habitats became negative, which leads to a unimodal instead of a positive PBR along the RD gradient. By integrating resource effects and changing plant-plant interactions into a unified framework with the RD gradient, our work contributes to uncovering underlying mechanisms for inconsistent PBRs at large scales.

[Analysis of the causes of residual back pain in the early and late stages after percutaneous vertebral augmentation].

OBJECTIVE: To explore the influencing factors of the residual back pain in patient with osteoporotic vertebral compression fractures(OVCFs) in the early and late stages after percutaneous vertebral augmentation(PVA), and analyze the correlation between these factors and the residual back pain after PVA. METHODS: From March 2018 to December 2019, 312 patients with OVCFs who treated with PVA were collected. According to the inclusion and exclusion criteria, a total of 240 patients were included in this retrospective study. There were 59 males and 181 females, aged from 50 to 95 years old with an average of (76.11±10.72) years old, and 50 cases of fractures located in the thoracic region (T5-T10), 159 cases in the thoracolumbar region (T11-L2), and 31 cases in the lumbar region (L3 and below). The first day after PVA was regarded as the early postoperative period, and the seventh day was regarded as the late postoperative period. According to the visual analogue scale (VAS), the patients were divided into 4 groups:early postoperative pain relief group(group A, VAS≤4 scores), there were 121 patients, including 29 males and 92 females, aged from 50 to 90 years with an average of (75.71±11.00) years;early postoperative pain relief was not an obvious group (group B, VAS >4 scores), there were 119 patients, including 30 males and 89 females, aged from 53 to 95 years with an average of (76.51±10.46) years; late postoperative pain relief group (group C, VAS≤ 4 scores), there were 172 patients, including 42 males and 130 females, aged from 50 to 95 years with an average of (76.20±10.68) years; late postoperative pain relief was not obvious group (group D, VAS>4 scores), there were 68 patients, including 17 males and 51 females, aged from 53 to 94 years old with an average of (75.88±10.91) years old. The age, gender, bone mineral density(BMD), injured vertebral segment, preoperative thoracolumbar fascial condition, surgical methods, single or bilateral puncture, the amount of bone cement injection, anterior vertebral height recovery rate and central vertebral height recovery rate in the 4 groups were analyzed by univariate analysis. The statistically significant factors were put into a Logistic regression to analyze the correlation between these factors and residual back pain after PVA. RESULTS: Univariate analysis showed that the residual back pain in the early stage after PVA was correlated with BMD, preoperative thoracolumbar fascial injury, single or bilateral puncture, the amount of bone cement injection, anterior vertebral height recovery rate and central vertebral height recovery rate(P<0.05). The residual back pain in the late postoperative period was related to BMD, injured vertebral segment, surgical methods, the amount of bone cement injection, anterior vertebral height recovery rate and central vertebral height recovery rate(P<0.05). Multivariate Logistic regression analysis showed that thoracolumbar fascial injury(OR=4.938, P=0.001), single or bilateral puncture(OR=5.073, P=0.002) were positively correlated with the residual back pain in the early stage after PVA(B>0), which were risk factors;the BMD (OR=0.211, P=0.000) and anterior vertebral height recovery rate (OR=0.866, P=0.001) were negatively correlated with the residual back pain in the early stage after PVA(B<0), which were protective factors. In the late stage after PVA, the BMD(OR=0.448, P=0.003), the amount of bone cement injection (OR=0.648, P=0.004) and anterior vertebral height recovery rate (OR=0.820, P=0.000) were negatively correlated with residual back pain(B<0), which were protective factors. CONCLUSION: The decrease of BMD, injury of the thoracolumbar fascia, single or bilateral puncture, poor recovery of anterior vertebral height and insufficient injection of bone cement are closely related to the occurrence of residual back pain after PVA, which affect the relief of residual back pain in the early and late postoperative periods.

Effects of Nitrogen Addition on Plant Properties and Microbiomes Under High Phosphorus Addition Level in the Alpine Steppe.

Nitrogen (N) addition can increase the vegetative growth, improve the plant production, and restore the degraded terrestrial ecosystems. But, it simultaneously aggravates the soil phosphorus (P) limitation for plant growth, thus affecting its positive effects on ecosystems. However, how plants and soil microorganisms will change under conditions of high P content in soil is still unknown. In this study, we explored the effects of three levels of N addition (0, 7.5, and 15 g.N.m-2.year-1) on plants and microorganisms at the high P addition level (13.09 g.P.m-2.year-1) in the alpine steppe. We found that the soil microbial community composition had no significant difference between different N addition levels, and the soil AN and AP had a significant effect on the phospholipid fatty acid (PLFA) composition. The abundance of the core PLFAs (i.e., 16:1ω7c, 16:0, a17:1, i17:0, 18:1ω9c, and 18:1ω7c) also remained unchanged after N addition, and microbes at individual, population, and community levels were all correlated with SOM, AK, AN, and pH. Conversely, plant biomass and nutrient content showed linear trends with increasing N addition, especially the dominant functional groups. Specifically, the biomass and plant tissue N content of Gramineae, and the total N content of aboveground biomass were all improved by N addition. They were correlated with soil ammonium and AP. The structural equation modeling (SEM) demonstrated that N addition had a direct negative effect on soil microbial biomass, but an indirect positive effect on aboveground biomass via soil ammonium. These findings clarify the importance of N-amendment in regulating plants and microorganisms under high P conditions and provide a better understanding of the N-added effects in the alpine steppe.

Tree diversity and soil chemical properties drive the linkages between soil microbial community and ecosystem functioning.

Microbial respiration is critical for soil carbon balance and ecosystem functioning. Previous studies suggest that plant diversity influences soil microbial communities and their respiration. Yet, the linkages between tree diversity, microbial biomass, microbial diversity, and microbial functioning have rarely been explored. In this study, we measured two microbial functions (microbial physiological potential, and microbial respiration), together with microbial biomass, microbial taxonomic and functional profiles, and soil chemical properties in a tree diversity experiment in South China, to disentangle how tree diversity affects microbial respiration through the modifications of the microbial community. Our analyses show a significant positive effect of tree diversity on microbial biomass (+25% from monocultures to 24-species plots), bacterial diversity (+12%), and physiological potential (+12%). In addition, microbial biomass and physiological potential, but not microbial diversity, were identified as the key drivers of microbial respiration. Although soil chemical properties strongly modulated soil microbial community, tree diversity increased soil microbial respiration by increasing microbial biomass rather than changing microbial taxonomic or functional diversity. Overall, our findings suggest a prevalence of microbial biomass over diversity in controlling soil carbon dynamics.

Phosphorus mediates soil prokaryote distribution pattern along a small-scale elevation gradient in Noijin Kangsang Peak, Tibetan Plateau.

Environmental factors that are important in shaping microbe community structure are less explored along elevation in the alpine grassland ecosystem of Tibet Plateau, which is generally phosphorus limited. Here, we examined soil prokaryote communities at three elevations to explore soil prokaryote community distribution and mediation factors in Noijin Kangsang Peak, Tibetan Plateau. Results showed prokaryote community compositions differed significantly by elevations. Topsoil or subsoil prokaryote richness and Shannon diversity were significantly lower at the middle than other elevations, while significantly higher aboveground biomass (AGB) and available P (AP) were found at the middle elevation. The importance of P for both soil layers was discovered by variation partitioning analysis based on redundancy analysis, finding that soil AP and total phosphorus, interacted with pH, explained 43% the variance in topsoil prokaryote community compositions, while soil AP, as well as AGB, explained 44% in subsoil. Consistently, structural equation model also revealed that AP was a mediating factor for prokaryote community diversity. Other than plant beta diversity, soil prokaryote beta diversity positively correlated with AP difference significantly. Taken together, the distribution patterns of soil prokaryote community were distinct along elevations even in a small scale in Noijin Kangsang Peak and was likely mediated predominantly by soil AP in both topsoil and subsoil.

Changes in Biomass and Quality of Alpine Steppe in Response to N & P Fertilization in the Tibetan Plateau.

In the alpine steppe zone on the Central Tibetan Plateau, a large amount of area has been degraded due to natural and artificial factors. N & P fertilization is widely accepted to recover degraded pastures in other regions all over the world. However, it is not clear how alpine steppe communities respond to N & P fertilization, and what is the optimal application rate, in the perspective of forage production. To attempt to explore these questions, in July 2013, two fencing sites were designed in Baingoin County with 12 treatments of different levels of nitrogen (N0: 0; N1: 7.5 g m(-2) yr(-1); N2: 15 g m(-2) yr(-1)) & phosphate (P0: 0; P1: 7.5 gP2O5 m(-2) yr(-1); P2: 15 gP2O5 m(-2) yr(-1); P3: 30 gP2O5 m(-2) yr(-1)). The results indicated N&P addition was capable to ameliorate the quality of the two sites in the Tibetan Plateau steppe. Increasing N application level resulted in significant increment in Gramineae and total biomass in the two sites. P addition significantly improved the quantity of Compositae, total biomass and the biomasss of other species in site II, while it only significantly improved the total biomass in site I. Gramineae was much more sensitive to N-induced changes than P-induced changes, and this indicated N addition was better to ameliorate the quality of plateau steppe than P-induced changes. No strong evidence was found for critical threshold within 15 g N m(-2) yr(-1), and there was decreasing tendency when P addition rate was above 15 g m(-2) yr(-1). N&P has the potential to accelerate soil acidification, which improved the content of available K, likely as a result of nonsignificant correlation between biomass and soil moisture. This work highlights the the tradeoffs that exist in N and P addition in recovering degraded steppe.