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MicroRNA (miRNA) plays a regulatory role in periodontitis. This study aimed to explore whether miR-29a could affect lipopolysaccharides (LPSs)-induced injury in human gingival fibroblasts (HGFs) through the competitive endogenous RNAs (ceRNA) mechanism. Periodontal ligament (PDL) tissues and HGFs were derived from patients with periodontitis and healthy volunteers. Periodontitis cell model was established by treating HGFs with LPS. Expression levels of circ_0036490, miR-29a, and DKK1 were evaluated by the reverse transcription quantitative real-time PCR (RT-qPCR) method. Western blotting assay was performed to assess protein expression levels of pyroptosis-related proteins and Wnt signalling related proteins. Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. Concentration of lactate dehydrogenase (LDH), interleukin (IL)-1β, and IL-18 were determined by Enzyme-linked immunosorbent assay (ELISA). Pyroptosis rate were determined by flow cytometry assay to evaluate pyroptosis. The interaction between miR-29a and circ_0036490 or DKK1 was verified by dual-luciferase reporter and RNA pull-down assays. MiR-29a expression was lower in PDL tissues of patients with periodontitis than that in healthy group; likewise, miR-29a was also downregulated in LPS-treated HGFs. Overexpression of miR-29a increased cell viability and decreased pyroptosis of HGFs induced by LPS while inhibition of miR-29a exerted the opposite role. MiR-29a binds to circ_0036490 and elevation of circ_0036490 contributed to dysfuntion of LPS-treated HGFs and reversed the protection function of elevated miR-29a. In addition, miR-29a targets DKK1. Overexpression of DKK1 abrogated the effects of overexpressed miR-29a on cell vaibility, pyroptosis, and protein levels of Wnt signalling pathway of LPS-treated HGFs. Circ_0036490 and DKK1 competitively bind miR-29a to promote LPS-induced HGF injury in vitro. Wnt pathway inactivated by LPS was activated by miR-29a. Thence, miR-29a may be a promising target for periodontitis.

Grassland which covers 40% of terrestrial land is an important ecosystem having a multitude of functions, which has suffered various degrees of degradation with the interaction between global climate change and unreasonable human utilization (e.g., grazing and reclamation). Improved understanding of soil and microbial community diversity during meadow steppe degradation is crucial for predicting degradation mechanisms and restoration strategies. Here, we used Illumina sequencing technology to investigate the patterns of soil microbial community structure and the driving factors of its change across different degradation degrees of meadow steppe [i.e., non-degraded grasslands (NDG), lightly degraded grasslands (LDG), moderately degraded grasslands (MDG), and severely degraded grasslands (SDG)] south of the Greater Khingan Mountains. Our results showed a significant variation in soil properties, enzyme activity, and soil metal elements across the degraded meadows. Soil available phosphorus (AP), urease (UE), and cellulase (CL) in soils increased with the intensity of grassland degradation. Grassland degradation significantly decreased soil bacterial and fungal richness. In addition, grassland degradation significantly increased the relative abundance of Firmicutes (from 1.65% to 5.38%) and Myxococcota (from 2.13% to 3.13%). Degradation considerably increased the relative abundance of Ascomycota (from 66.54% to 75.05%), but decreased Basidiomycota (from 18.33% to 9.92%). The relative abundance of nitrogen fixation and cellulolysis decreased significantly due to grassland degradation. For fungal functional guilds, the relative abundance of pathotrophs increased while saprotrophs decreased significantly with increasing severity of degradation. Total nitrogen (TP), AP, available potassium (AK), manganese (Mn), lead (Pb), UE, sucrase (SC), and alcalase protease (ALPT) were the main drivers of soil bacterial community composition, while TP, AP, AK, Pb, UE, and SC were the main drivers of soil fungal community composition in the degraded grassland. Our findings demonstrated that severe grassland degradation has an enormous effect on soil microbial communities and soil physicochemical dynamics. These findings improve our theoretical understanding of the interactions between soil microbial populations and soil environmental variables in degraded grassland.