Dysregulated long non-coding RNAs participate in the development of diabetic cerebral ischemia. This study aimed to investigate the underlying mechanism of lncRNA MALAT1 in diabetic cerebral ...ischemia.
Middle cerebral artery occlusion (MCAO) was performed to establish diabetic cerebral I/R in vivo. TTC and neurological deficits assessment were performed to assess cerebral ischemic injury. LDH was conducted to detect cytotoxicity. RT-qPCR and western blotting assays were applied to determine mRNA and protein expression. Flow cytometry was performed to detect the pyroptosis of BV2 cells. Immunofluorescence and FISH were conducted for subcellular localization of MALAT1 and STAT1. ELISA was performed to determine cytokine release. Dual luciferase reporter, RIP, and ChIP assays were used to validate the interaction between STAT1 and MALAT1/NLRP3. Diabetes aggravated cerebral injury in vivo and in vitro. Diabetic cerebral ischemia induced inflammatory response and inflammation-induced cell pyroptosis.
MALAT1 was overexpressed in diabetic cerebral ischemia models in vivo and in vitro. However, knockdown of MALAT1 suppressed inflammatory response and the pyroptosis of BV2 cells. Moreover, MALAT1 interacted with STAT1 to transcriptionally activate NLRP3. Knockdown of STAT1 significantly reversed the effects of MALAT1. Furthermore, STAT1 promotes the MALAT1 transcription. MALAT1 interacts with STAT1 to promote the pyroptosis of microglias induced by diabetic cerebral ischemia through activating NLRP3 transcription.
Thus, knockdown of MALAT1 may be a potential promising therapy target for diabetic cerebral ischemia.
Circular RNAs (circRNAs) have been progressively recognized as critical regulators in the pathology and pathophysiology of central nervous system disease. However, the potential role of circRNAs in ...intracerebral hemorrhage (ICH) is still largely unclear. Here, we demonstrate that circTrim37 expression was significantly upregulated at 3 days after ICH by circular RNA microarray and qPCR assays. Overexpression of circTrim37 could significantly ameliorate brain injury volume, brain edema, neurologic deficits, and inflammation in vivo after ICH. CircTrim37 promotes M2 polarization while restrains M1 polarization in vitro. Furthermore, circTrim37 acts as an endogenous sponge for miR-30c-5p, thereby inhibiting miR-30c-5p activity, leading to the upregulation of SOCS3 and making the balance of microglial response towards an M2 phenotype. Taken together, our results indicate the participation of circTrim37 and its coupling mechanism in ICH and provide a novel therapeutic target for ICH.
Diabetes mellitus causes brain microvascular endothelial cell (MEC) damage, inducing dysfunctional angiogenic response and disruption of the blood-brain barrier (BBB). Canagliflozin is a ...revolutionary hypoglycemic drug that exerts neurologic and/or vascular-protective effects beyond glycemic control; however, its underlying mechanism remains unclear. In the present study, we hypothesize that canagliflozin ameliorates BBB permeability by preventing diabetes-induced brain MEC damage. Mice with high-fat diet/streptozotocin-induced diabetes received canagliflozin for 8 weeks. We assessed vascular integrity by measuring cerebrovascular neovascularization indices. The expression of specificity protein 1 (Sp1), as well as tight junction proteins (TJs), phosphorylated AMP-activated protein kinase (p-AMPK), and adenosine A2A receptors was examined. Mouse brain MECs were grown in high glucose (30 mM) to mimic diabetic conditions. They were treated with/without canagliflozin and assessed for migration and angiogenic ability. We also performed validation studies using AMPK activator (AICAR), inhibitor (Compound C), Sp1 small interfering RNA (siRNA), and adenosine A2A receptor siRNA. We observed that cerebral pathological neovascularization indices were significantly normalized in mice treated with canagliflozin. Increased Sp1 and adenosine A2A receptor expression and decreased p-AMPK and TJ expression were observed under diabetic conditions. Canagliflozin or AICAR treatment alleviated these changes. However, this alleviation effect of canagliflozin was diminished again after Compound C treatment. Either Sp1 siRNA or adenosine A2A receptor siRNA could increase the expression of TJs. Luciferase reporter assay confirmed that Sp1 could bind to the adenosine A2A receptor gene promoter. Our study identifies the AMPK/Sp1/adenosine A2A receptor pathway as a treatment target for diabetes-induced cerebrovascular injury.
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Intracerebral hemorrhage (ICH) is a lethal stroke with high mortality or disability. However, effective therapy for ICH damage is generally lacking. Previous investigations have suggested that ...lysosomal protein transmembrane 5 (LAPTM5) is involved in various pathological processes, including autophagy, apoptosis, and inflammation. In this study, we aimed to identify the expression and functions of LAPTM5 in collagenase-induced ICH mouse models and hemoglobin-induced cell models. We found that LAPTM5 was highly expressed in brain tissues around the hematoma, and double immunostaining studies showed that LAPTM5 was co-expressed with microglia cells, neurons, and astrocytes. Following ICH, the mice presented increased brain edema, blood-brain barrier permeability, and neurological deficits, while pathological symptoms were alleviated after the
LAPTM5
knockdown. Adeno-associated virus 9-mediated downregulation of
LAPTM5
also improves ICH-induced secondary cerebral damage, including neuronal degeneration, the polarization of M1-like microglia, and inflammatory cascades. Furthermore, LAPTM5 promoted activation of the nuclear factor kappa-B (NF-κB) pathway in response to neuroinflammation. Further investigations indicated that brain injury improved by
LAPTM5
knockdown was further exacerbated after the overexpression of receptor-interacting protein kinase 1 (
RIP1
), which is revealed to trigger the NF-κB pathway. In vitro experiments demonstrated that
LAPTM5
silencing inhibited hemoglobin-induced cell function and confirmed regulation between RIP1 and LAPTM5. In conclusion, the present study indicates that LAPTM5 may act as a positive regulator in the context of ICH by modulating the RIP1/NF-κB pathway. Thus, it may be a candidate gene for further study of molecular or therapeutic targets.
The increase of soil nitrogen (N) availability may alter soil microbial community composition and the natural N cycle in forest ecosystems. However, the responses of soil microbial nitrogen ...functional genes (NFGs) to N addition and their consequent effect on the N-cycle processes are poorly understood. In this study, soil samples were collected from an artificial Pinus tabulaeformis forest located in Loess Plateau (China) to which N at four different concentrations was added (0 N0, 3 N3, 6 N6, and 9 N9 g N m−2 y−1) for 4 years. We quantified the relative abundance of NFGs using functional gene microarray GeoChip 5.0 and determined net N transformation and N2O emission rates in a 14-day incubation experiment. The results showed that N3 and N6 treatments did not significantly affect the total relative abundance and diversity of NFGs assemblage but significantly increased the relative abundance of specific genes for the NH3 cycle (ureC, nirA, and nrfA), and nitrification (amoA) and denitrification (norB). These positive effects were related to the increase in soil organic C, NO3−-N, and microbial biomass C (MBC). N9 treatment significantly decreased the relative abundance of all NFGs, and this negative impact was correlated with reduced dissolved organic C and MBC. Moreover, N addition significantly changed net N nitrification, mineralization, and N2O emission rates, and NFGs explained the higher variances in the N transformation processes than soil properties. Specifically, ammonia-oxidizing archaea (amoA-AOB) and MBC were the key factors related to net N nitrification; ureC, nirK, and MBC were the key factors related to net N mineralization; and narG and nirS were the key factors related to N2O emission. Our results show that global N deposition may mainly influence N transformation processes by regulating the corresponding NFG relative abundance, thereby affecting the N cycle in forest soils.
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•Effects of soil microbial N functional genes (NFGs) on N-cycle processes are unclear.•Low N addition increased the relative abundance of some NFGs.•High N addition significantly decreased the relative abundance of all NFGs.•N addition effects on NFGs were influenced by C and N nutrient status.•NFG relative abundance was the key factor controlling soil N transformation.
•Changes in composition and C and N cycling functions of microbes were studied.•Microbial communities tended to shift from r- to K-strategists, both at the phylum and genus levels.•Bacterial ...communities were influenced by available P contents and soil C:N ratios.•Fungal communities were affected by ammonium N contents and root biomass.•Ammonium N and activated C contents affected microbial community function.
Vegetation succession is one of the most important factors driving changes in microorganisms. It is unclear, however, how the microbial composition and the potential function of C and N cycling change with forest secondary succession. Using soil metagenomic sequencing methods, we studied these changes in bacterial and fungal communities with secondary succession from cropland to a Quercus liaotungensis forest over approximately 120 years on the Loess Plateau of China. The results revealed the following. (1) Soil microbial biomass C, N, and P increased significantly in topsoil (0–20 cm) with vegetation succession. (2) The abundances of bacteria increased initially and then decreased slightly, whereas an increase in fungal abundances and the ratio of fungi to bacteria was detected along a successional gradient. Microbial communities tended to shift from r- to K-strategists, both at the phylum and genus levels. (3) With vegetation succession, the abundances of C and N cycle-related potential functional genes first significantly increased and then stabilized. Among them, the relative abundances of recalcitrant C degradation-, N fixation-, and ammonification-related genes increased, whereas labile C degradation-, N reduction-, and denitrification-related genes tended to decrease. (4) Redundancy analysis indicated that bacterial communities were influenced by available phosphorus contents and soil C: N ratios, and that fungal communities were mainly affected by ammonium N contents and root biomass. (5) Predicted microbial functional genes were affected by ammonium N and activated C contents. Our study showed that with vegetation succession, microbe communities tended to shift from r- to K-strategists both at the phylum and genus levels, which increased the abundance of organisms expressing C- and N-cycle related genes.
Background and aims
It is unclear how atmospheric nitrogen (N) deposition influences CO
2
release from grassland by affecting heterotrophic respiration of bulk and rhizosphere soils and how the ...heterotrophic rhizosphere respiration of different grass species responds to N deposition.
Methods
In this study, we investigated the effects of N addition on heterotrophic respiration of bulk and rhizosphere soils associated with the dominant species (
Bothriochloa ischaemum
) and subdominant species (
Artemisia sacrorum
and
Stipa capillata
) in the grassland treated with N fertilizer (0,3,9 g N m
−2
y
−1
) for eight years.
Results
Low-N addition significantly increased cumulative CO
2
-C emissions of bulk soil by 22.91% and rhizosphere soil of
A. sacrorum
by 72.26%, while high-N addition significantly increased that of rhizosphere soil of
(A) sacrorum
by 37.38% and
S. capillata
by 13.71%. There was no clear response to N addition for
(B) ischaemum
. Heterotrophic rhizosphere respiration of
B. ischaemum
was most strongly related to stable-C-degrading functional genes, whereas that of
A. sacrorum
and
S. capillata
was most strongly related to labile-C-degrading functional genes. C-degrading functional genes in rhizosphere soil were significantly related to root morphological characteristics, especially specific root length, specific root surface area, and root average diameter rather than root exudation rates.
Conclusion
The present study revealed that N addition could affect heterotrophic soil respiration by changing labile-C and stable-C degrading functional genes, which in the rhizosphere of different plant species were regulated by their root functional traits.
A versatile pilot-scale two-stage membrane plant for CO2 capture from different simulated exhaust gases was designed and constructed. The capture efficiency was investigated in detail under different ...operating pressures, humidifier temperatures, and stage-cuts based on the graded CO2 contents of the initial feed gas (i.e., 14%, 25%, and 35%), which were similar to the typical CO2 contents of industrial exhaust gas emitted from coal-fired power plants, steel mill/cement plants, and factories associated with high–CO2–concentration operations, respectively. When the CO2 capture rates were 61.3%, 60.7%, and 53.9% in the three cases, the product gas CO2 purities could reach 78.5%, 87.2%, and 96.3%, respectively. This study also represents the first instance of developing an actual design and layout of a three-stage and three-step membrane plant, which will be built in early 2021 in Nanjing, China, and is expected to achieve the targets of 95% CO2 product purity and 90% CO2 capture rate. The experience gained through this study could accelerate the industrial application of membrane technology for CO2 capture.
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•A versatile pilot-scale two-stage membrane plant was designed and constructed.•It provided a picture of CO2 capture covering different industrial occasions.•It was the first time to present an actual design and layout of membrane plant.•The well-designed plant had the potential to approach the DOE's capture target.
•Low N addition significantly increased the gene abundances for degrading labile C.•High N addition significantly decreased the abundance of all C-cycling genes.•N addition influenced C-cycling genes ...through altering soil C and N nutrient status.•C-cycling gene abundances play an important role in SOC decomposition.
Nitrogen (N) deposition affects soil organic carbon (SOC) decomposition, therefore altering the global terrestrial carbon (C) cycle. However, it remains unclear how N deposition affects SOC decomposition by regulating microbial community composition and function, especially C-cycling functional gene composition. We investigated the effects of N addition (0, 3, 6, and 9 g N m−2y–1) on the composition of soil microbial C-cycling functional gene, SOC-degrading enzyme activities, and CO2 emissions in a Pinus tabulaeformis forest. Under low N addition (3 or 6 g N m−2y–1), labile C-degradation gene abundances were significantly increased. Under high N addition (9 g N m−2y–1), C-cycling functional gene abundance and diversity were significantly decreased. These effects were related to the changes in soil NO3–-N, dissolved organic C, total N, and microbial biomass C contents. Furthermore, low N addition stimulated the activities of SOC-degrading enzyme and CO2 emissions, whereas high N addition had the inhibitory effect. C-degradation gene abundances were significantly correlated with the SOC-degrading enzyme activities and CO2 emissions. Increase in CO2 emission rates were related to the high microbial functional potentials for labile C degradation under low N addition, whereas the lower CO2 emission rates were related to the low microbial functional potentials for labile as well as recalcitrant C degradation under high N addition. Our study indicated that N deposition may change SOC decomposition by altering the abundance of labile C and recalcitrant C degradation genes.
