Neuroprotection of Emodin by Inhibition of Microglial NLRP3 Inflammasome-Mediated Pyroptosis.

BACKGROUND: Neuroinflammation triggered by chronic cerebral ischemia-induced microglial pyroptosis is a significant contributor to vascular cognitive impairment. It has been shown that emodin possesses anti-inflammatory and neuroprotective properties, however, it's potential molecular and signaling transduction pathway remains to be illuminated. This study researched the neuroprotective mechanisms of emodin focussing on emodin effects on lipopolysaccharide/adenosine triphosphate (LPS/ATP)-caused pyroptosis in BV2 cells and HT-22 hippocampal neurons. METHODS: To explore the neuroprotective effect of emodin, Emodin was applied to BV2 cells, HT-22 hippocampal neurons, and BV2/HT-22 co-cultures stimulated with LPS/ATP to evaluate the cell morphology, levels of inflammatory factors, NLRP3 inflammatory inflammasome activity and focal pyroptosis-related protein expression, as same as neuronal apoptosis. RESULTS: Emodin alleviated LPS/ATP-induced pyroptosis of BV2 cells by preventing the activity of the NLRP3 inflammasome and the cleavage of pyroptosis executive protein Gasdermin D (GSDMD). Furthermore, levels of interleukin (IL)-18, IL-1ß and tumor necrosis factor (TNF)-α were reduced, the apoptosis of HT-22 hippocampal neurons was attenuated, and cell viability was restored. CONCLUSIONS: Emodin can antagonize microglial neurotoxicity by inhibiting microglial pyroptosis, thereby exerting anti-inflammatory and neuroprotective effects.

lncRNA XIST induces Aß accumulation and neuroinflammation by the epigenetic repression of NEP in Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of dementia globally, but effective treatment is lacking. We aimed to explore lncRNA XIST role in AD and the mechanisms involved in the effect of changes in lncRNA XIST on the expression of Aß-degrading enzymes. The mouse model of AD and the cell model induced by Aß were established. LncRNA XIST, IDE, NEP, Plasmin, ACE, EZH2 expressions and distribution of XIST in the nucleus and cytoplasm were detected by qRT-PCR. Inflammatory cytokines IL-6, IL-1ß, TNFα, IL-8, and Aß42 levels were detected by ELISA. TUNEL was used to measure brain tissue damage. Cell proliferation was detected by CCK-8 assay. Flow cytometry detected cell apoptosis. RIP validated the combination of XIST and EZH2. ChIP verified that XIST recruits EZH2 to mediate enrichment of HEK27me3 in the NEP promoter region. The protein expression in brain tissues and cells was detected by Western blot. The expression of lncRNA XIST was increased in AD mice and cell models. Inflammation and injury of nerve cells occurred in AD mice and cell models. The knockdown of lncRNA XIST alleviated Aß-induced neuronal inflammation and damage. LncRNA XIST affected the expression of Aß-degrading enzyme NEP, and lncRNA XIST was negatively correlated with NEP expression in AD mice. LncRNA XIST regulated NEP expression partly through epigenetic regulation by binding with EZH2. LncRNA XIST mediated neuronal inflammation and injury through epigenetic regulation of NEP. Overall, our study found that lncRNA XIST induced Aß accumulation and neuroinflammation by the epigenetic repression of NEP in AD.

Genetic variation and population structure of different geographical populations of Meretrix petechialis based on mitochondrial gene COI.

The hard clam (Meretrix petechialis) is a commercially important shellfish in China. To provide valuable insights into management and conservation of M. petechialis, we investigated the genetic variation and population structure of M. petechialis by analysing samples from nine geographical populations. In this study, the genetic diversity and differentiation of nine populations of M. petechialis were assessed using the mitochondrial cytochrome oxidase subunit I (mtCOI) gene. A total of 90 COI sequences were obtained and each COI sequence was 699 bp in length. Fifty-one haplotypes were identified with 10 haplotypes shared among populations. The haplotype diversity was highest in Fujian, Panjin and Jiangsu (0.9778 ± 0.0540) and lowest in Dalian (0.7778 ± 0.1374). The nucleotide diversity was highest in Panjin (0.453401 ± 0.240463) and lowest in Jiangsu (0.006213 ± 0.004141). Neutral test (Fu's Fs) and mismatch distribution analysis revealed that the hard clam experienced a population expansion event. Analysis of molecular variance (AMOVA) indicated that 91.7% of the genetic variance was within populations and 0.52% of the variance was among populations, demonstrating significant genetic differentiation among populations (P < 0.05). The neighbour-joining tree showed that the haplotypes were not clustered according to the geographical location, but some haplotypes from the same or neighbouring locations grouped together. The results obtained in this study provide useful information on the genetic diversity and population structure of M. petechialis and shed light on the management and protection of resources of M. petechialis in the northwestern Pacific.

Molecular cloning and expression analysis of inhibitor of growth protein 3 (ING3) in the Manila clam, Ruditapes philippinarum.

Inhibitor of growth protein 3 (ING3), a new member of ING family, is involved in the regulation of various processes. In this study, a full-length cDNA of ING3 (named as RpING3) was cloned from the gill of Ruditapes philippinarum by rapid amplification of cDNA ends method for the first time. The cDNA obtained was 1442 bp exclusive of poly (A) residues with a 1248 bp open reading frame encoding 415 amino acids. The RpING3 protein has a calculated molecular weight of 46.59 kDa and isoelectric point of 6.62. Two conserved motif and some functional sites were found. Tissue distribution analysis of the RpING3 mRNA revealed that the RpING3 expression level was much higher in gill and digestive gland while lower in mantle, foot and adductor muscle. The temporal expression of RpING3 in digestive gland after lead exposure was recorded by quantitative real-time PCR. The result showed that RpING3 was rapidly up-regulated at 6 h post-exposure and reached tenfold of the control group. These results suggest that RpING3 dependent signaling pathway is present in Manila clam and RpING3 may play important roles in protecting cells from heavy metal damage in R. philippinarum.

[Effects of starvation and refeeding in winter on the growth, survival, and biochemical composition of different size Ruditapes philippinarum].

From December 2007 to April 2008, a laboratory experiment was conducted to study the effects of various starvation periods followed by the same refeeding period on the growth, survival, and biochemical composition of different size Ruditapes philippinarum at water temperature 3.0 degrees C-4.2 degrees C, salinity 25-27, and pH 7.90-8.16. No significant differences in the growth characteristics of R. philippinarum at low temperatures were observed among different size groups. The tolerance to starvation increased with increasing size, while the survival rate decreased with increasing starvation period, point-of-no return (PNR50) was not observed during the study period. For the larger size group (7 mm), the body moisture and lipid concentrations generally decreased with increasing starvation period. During starvation, the body protein content increased initially as a result of lipid being utilized for energy, but decreased thereafter when the lipid was depleting. Ash content remained unchanged during the study period, and was not affected by starvation or refeeding.