Report on Cardiac Gross Pathologic Measurements of Sudden Cardiac Death in Adults.

OBJECTIVES: To analyze the gross pathological data of sudden cardiac death (SCD) with different causes, to provide data support for the identification of sudden cardiac death with unknown causes. METHODS: A total of 167 adult SCD cases in the archive of the Forensic Expertise Institute of Nanjing Medical University from 2010 to 2020 were collected. The gross pathological data of SCD cases were summarized and the characteristics of different causes of death were statistically analyzed. RESULTS: The ratio of male to female SCD cases was 3.4∶1. Coronary heart disease was the leading cause of SCD, and mainly distributed in people over 40 years old. SCD caused by myocarditis was mainly distributed in young people and the mean age of death was (34.00±9.55) years. By analyzing the differences in cardiac pathological parameters of SCD with different causes, it was found that the aortic valve circumference was significantly dilated in the SCD caused by aortic aneurysm or dissection (P<0.05). The heart weight of SCD caused by aortic aneurysm or dissection and combined factors was greater, and both pulmonary and tricuspid valvular rings were dilated in the SCD caused by combined factors in adult males (P<0.05). CONCLUSIONS: Various gross pathological measures of SCD with different causes are different, which has reference value in the cause of death identification of SCD.

Identification of Serum-Based Metabolic Feature and Characteristic Metabolites in Paraquat Intoxicated Mouse Models.

Paraquat (PQ) is a widely used herbicide which can cause high mortality to humans. However, relatively few studies focus on metabolic feature of PQ intoxication for investigating the underlying mechanisms. Here we performed non-targeted metabolomics profiling of serum samples from acute and chronic PQ intoxicated mouse models by gas chromatography time-of-flight mass spectrometry (GC-TOF/MS) to identify metabolic feature and characteristic metabolites of acute and chronic PQ intoxication. Results showed that 3-indolepropionic acid (IPA) and pathway of glycine, serine, and threonine metabolism were significantly altered after acute PQ intoxication; 2-hydroxybutyric acid and the ratio of L-serine/glycine were of significance between acute and chronic PQ intoxication. Then targeted metabolomics profiling was conducted by liquid chromatography-mass spectrometry (LC-MS) analysis to confirm the changes of IPA after acute PQ intoxication. Moreover, IPA-producing gut bacteria in feces were quantified by qRT-PCR to explain the varied IPA serum concentration. Clostridium botulinum and Peptostreptococcus anaerobius were significantly suppressed after acute PQ intoxication. The data suggested that PQ caused oxidative damage partially through suppression of anti-oxidative metabolite producing gut bacteria. In conclusion, we identified characteristic metabolites and pathway of acute and chronic PQ intoxication which could be potential biomarkers and therapeutic targets.

The activation of STIM1 mediates S-phase arrest and cell death in paraquat induced acute lung intoxication.

Calcium signaling and oxidative stress are tightly linked to cell cycle and cell death in response to a number of stress conditions. Recent study indicated that stromal interaction molecule 1 (STIM1) is the endoplasmic reticulum calcium sensor. However, the regulatory mechanisms and the role of STIM1 in paraquat (PQ)-induced acute lung intoxication remain elusive. The aim of this study was to explore the molecular and cellular mechanisms of PQ induced acute intoxication in the lung, and further determine whether calcium signaling and reactive oxygen species (ROS) participate in the regulatory mechanism. Our data demonstrated that PQ (500 µM, 24 h) induced intracellular ROS production and enhanced store-operated calcium entry (SOCE) activity which is correlated to STIM1 activation. In addition, PQ (500 µM, 24-48 h) caused accelerated cell cycle G1/S transition and then arrested in S phase. While knock-outing STIM1 by CRISPR-CAS9 in 16HBE or inhibiting STIM1 mediated SOCE activation ameliorated cell death caused by acute PQ treatment, which also leaded to alleviating the cell accumulation in S phase through the modulation the expression of cyclinD1, p21, cyclinA2 and CDK2. In conclusion, STIM1 plays an important role in PQ induced cell cycle arrest and cell death in acute lung injury, which may provide us a new potential opportunity to target paraquat induced intoxication.

Epigenetic Regulation of Interleukin 6 by Histone Acetylation in Macrophages and Its Role in Paraquat-Induced Pulmonary Fibrosis.

Overexpression of interleukin 6 (IL-6) has been proposed to contribute to pulmonary fibrosis and other fibrotic diseases. However, the regulatory mechanisms and the role of IL-6 in fibrosis remain poorly understood. Epigenetics refers to alterations of gene expression without changes in the DNA sequence. Alternation of chromatin accessibility by histone acetylation acts as a critical epigenetic mechanism to regulate various gene transcriptions. The goal of this study was to determine the impact of IL-6 in paraquat (PQ)-induced pulmonary fibrosis and to explore whether the epigenetic regulations may play a role in transcriptional regulation of IL-6. In PQ-treated lungs and macrophages, we found that the mRNA and protein expression of IL-6 was robustly increased in a time-dependent and a dose-dependent manner. Our data demonstrated that PQ-induced IL-6 expression in macrophages plays a central role in pulmonary fibrosis through enhanced epithelial-to-mesenchymal transition (EMT). IL-6 expression and its role to enhance PQ-induced pulmonary fibrosis were increased by histone deacetylase (HDAC) inhibition and prevented by histone acetyltransferase (HAT) inhibition. In addition, the ability of CRISPR-ON transcription activation system (CRISPR-ON) to promote transcription of IL-6 was enhanced by HDAC inhibitor and blocked by HAT inhibitor. Chromatin immunoprecipitation experiments revealed that HDAC inhibitor increased histones activation marks H3K4me3 and H3K9ac at IL-6 promoter regions. In conclusion, IL-6 functioning through EMT in PQ-induced pulmonary fibrosis was regulated dynamically by HDAC and HAT both in vitro and in vivo via epigenetically regulating chromatin accessibility.

Genetic analysis of 15 mtDNA SNP loci in Chinese Yi ethnic group using SNaPshot minisequencing.

SNaPshot minisequencing is a rapid and robust methodology based on a single base extension with a labeled ddNTP. The present study detected 15 selected SNPs in the mitochondrial DNA (mtDNA) control and coding regions by minisequencing methodology using SNaPshot for forensic purpose. The samples were collected from 99 unrelated individuals of the Yi ethnic minority group in Yunnan Province. We have predominantly found high-frequency transitions (91.7%) and a significantly lower frequency of transversions (8.3%). The nt152, 489, 8701, 10,398, 16,183, and 16,362 loci were highly polymorphic, while the nt231, 473 and 581 loci were not polymorphic in the studied population. Based on these 15 SNPs, a total of 28 mtDNA haplotypes were defined in 99 individuals with the haplotype diversity of 0.9136. Also, we compared the mtDNA sequences of Yi group and other 9 populations worldwide and drew a Neighbor-Joining tree based on the shared 12 mtDNA SNP loci, which demonstrated a close relationship between Yi and Bai groups. In conclusion, the analysis of the 15 selected SNPs increases considerably the discrimination power of mtDNA. Moreover, the SNaPshot minisequencing method could quickly detect mtDNA SNPs, and is economical and sensitive. The set of selected 15 SNPs is highly informative and is capable for anthropology genetic analysis.

Mutation rate analysis at 19 autosomal microsatellites.

Previous studies have demonstrated that a large sample size is needed to reliably estimate population- and locus-specific microsatellite mutation rates. Therefore, we conducted a long-term collaboration study and performed a comprehensive analysis on the mutation characteristics of 19 autosomal short tandem repeat (STR) loci. The STR loci located on 15 of 22 autosomal chromosomes were analyzed in a total of 21,106 samples (11,468 parent-child meioses) in a Chinese population. This provided 217,892 allele transfers at 19 STR loci. An overall mutation rate of 1.20 × 10(-3) (95% CI, 1.06-1.36 × 10(-3) ) was observed in the populations across 18 of 19 STR loci, except for the TH01 locus with no mutation found. Most STR mutations (97.7%) were single-step mutations, and only a few mutations (2.30%) comprised two and multiple steps. Interestingly, approximately 93% of mutation events occur in the male germline. The mutation ratios increased with the paternal age at child birth (r = 0.99, p<0.05), but not maternal age. Last, with the combination analysis of the data from the southern Chinese population, we drew a picture of 19 STR mutations in China. In conclusion, the data from this study will provide useful information in parentage testing, kinship analysis, and population genetics.

Single nucleotide polymorphisms of mitochondrial DNA HVS-I and HVS-II in Chinese Bai ethnic group.

For forensic and population genetic purposes, a total of 125 unrelated volunteers' blood samples were collected from Chinese Bai ethnic minority group to analyze sequence variation of two hypervariable segments (HVS-I and HVS-II) in the mitochondrial DNA control region. Comparing the HVS-I and HVS-II sequences of the 125 Chinese Bais to the Anderson reference sequence, we found 86 polymorphic loci in HVS-I and 40 in HVS-II in mitochondrial DNA sequences of the Chinese Bai ethnic minority group, which defined 93 and 53 different haplotypes, respectively. Haplotype diversity and the mean pairwise differences were 0.992 ± 0.003 and 6.553 in HVS-I, and 0.877 ± 0.027 and 2.407 in HVS-II, respectively. We defined four macrohaplogroups R, M, N and D with the proportions ranging from 9.6% to 40.0%. With the analysis of the hypervariable domain from nucleotide 16 180-16 193 in HVS-I, our study revealed new haplotypes of sequence variations. In addition, the Fst metric, phylogenetic tree, and principal component analysis demonstrated a close genetic relationship between the Bai group and Chinese Han populations from South China, Changsha, and Guangdong. The results support that the Bai group is a multiorigin ethnic minority that has merged with the Chinese Han population.