Overexpression of miR-297b-5p in Mouse Insulin-Secreting Cells Promotes Metformin-Mediated Protection Against Stearic Acid-Induced Senescence by Targeting Igf1r.

BACKGROUND: A long-term consumption of saturated fat significantly increases the concentration of saturated fatty acids in serum, which accelerates the appearance of senescence markers in ß-cells and leads to their dysfunction. An understanding of the mechanisms underlying ß-cell senescence induced by stearic acid and the exploration of effective agents preventing it remains largely unclear. Here, we aimed to investigate the protective effect of metformin against stearic acid-treated ß-cell senescence and to assess the involvement of miR-297b-5p in this process. METHODS: To identify senescence, we measured senescence-associated ß-galactosidase activity and the expression of senescence-related genes. Gain and loss of function approaches were applied to explore the role of miR-297b-5p in stearic acid-induced ß-cell senescence. Bioinformatics analysis and a luciferase activity assay were used to predict the downstream targets of miR-297b-5p. RESULTS: Stearic acid markedly induced senescence and suppressed miR-297b-5p expression in mouse ß-TC6 cells, which were significantly alleviated by metformin. After transfection of miR-297b-5p mimics, stearic acid-evoked ß-cell senescence was remarkably prevented. Insulin-like growth factor-1 receptor was identified as a direct target of miR-297b-5p. Inhibition of the insulin-like growth factor-1 receptor prevented stearic acid-induced ß-cell senescence and dysfunction. Moreover, metformin alleviates the impairment of the miR-297b-5p inhibitor in ß-TC6 cells. Additionally, long-term consumption of a high-stearic-acid diet significantly increased senescence and reduced miR-297b-5p expression in mouse islets. CONCLUSIONS: These findings imply that metformin alleviates ß-cell senescence by stearic acid through upregulating miR-297b-5p to suppress insulin-like growth factor-1 receptor expression, thereby providing a potential target to not only prevent high fat-diet-induced ß-cell dysfunction but also for metformin therapy in type 2 diabetes.

The First High-quality Reference Genome of Sika Deer Provides Insights into High-tannin Adaptation.

Sika deer are known to prefer oak leaves, which are rich in tannins and toxic to most mammals; however, the genetic mechanisms underlying their unique ability to adapt to living in the jungle are still unclear. In identifying the mechanism responsible for the tolerance of a highly toxic diet, we have made a major advancement by explaining the genome of sika deer. We generated the first high-quality, chromosome-level genome assembly of sika deer and measured the correlation between tannin intake and RNA expression in 15 tissues through 180 experiments. Comparative genome analyses showed that the UGT and CYP gene families are functionally involved in the adaptation of sika deer to high-tannin food, especially the expansion of the UGT family 2 subfamily B of UGT genes. The first chromosome-level assembly and genetic characterization of the tolerance to a highly toxic diet suggest that the sika deer genome may serve as an essential resource for understanding evolutionary events and tannin adaptation. Our study provides a paradigm of comparative expressive genomics that can be applied to the study of unique biological features in non-model animals.

Inhibition of miR-146a-5p and miR-8114 in Insulin-Secreting Cells Contributes to the Protection of Melatonin against Stearic Acid-Induced Cellular Senescence by Targeting Mafa.

BACKGRUOUND: Chronic exposure to elevated levels of saturated fatty acids results in pancreatic ß-cell senescence. However, targets and effective agents for preventing stearic acid-induced ß-cell senescence are still lacking. Although melatonin administration can protect ß-cells against lipotoxicity through anti-senescence processes, the precise underlying mechanisms still need to be explored. Therefore, we investigated the anti-senescence effect of melatonin on stearic acid-treated mouse ß-cells and elucidated the possible role of microRNAs in this process. METHODS: ß-Cell senescence was identified by measuring the expression of senescence-related genes and senescence-associated ß-galactosidase staining. Gain- and loss-of-function approaches were used to investigate the involvement of microRNAs in stearic acid-evoked ß-cell senescence and dysfunction. Bioinformatics analyses and luciferase reporter activity assays were applied to predict the direct targets of microRNAs. RESULTS: Long-term exposure to a high concentration of stearic acid-induced senescence and upregulated miR-146a-5p and miR- 8114 expression in both mouse islets and ß-TC6 cell lines. Melatonin effectively suppressed this process and reduced the levels of these two miRNAs. A remarkable reversibility of stearic acid-induced ß-cell senescence and dysfunction was observed after silencing miR-146a-5p and miR-8114. Moreover, V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (Mafa) was verified as a direct target of miR-146a-5p and miR-8114. Melatonin also significantly ameliorated senescence and dysfunction in miR-146a-5pand miR-8114-transfected ß-cells. CONCLUSION: These data demonstrate that melatonin protects against stearic acid-induced ß-cell senescence by inhibiting miR-146a- 5p and miR-8114 and upregulating Mafa expression. This not only provides novel targets for preventing stearic acid-induced ß-cell dysfunction, but also points to melatonin as a promising drug to combat type 2 diabetes progression.

Comprehensive transcriptome analysis of sika deer antler using PacBio and Illumina sequencing.

Antler is the fastest growing and ossifying tissue in animals and it is a valuable model for cartilage/bone development. To understand the molecular mechanisms of chondrogenesis and osteogenesis of antlers, the PacBio Sequel II and Illumina sequencing technology were combined and used to investigate the mRNA expression profiles in antler tip, middle, and base at six different developmental stages, i.e., at 15th, 25th, 45th, 65th, 100th and 130th growth days. Consequently, we identified 24,856 genes (FPKM > 0.1), including 8778 novel genes. Besides, principal component analysis (PCA) revealed a significant separation between the growth stage (25th, 45th and 65th days) and ossification stage (100th and 130th days). COL2A1 gene was significantly abundant in the growth stage, whereas S100A7, S100A12, S100A8, and WFDC18 genes were abundant at the ossification stage. Subsequently screened to 14,765 significantly differentially expressed genes (DEGs), WGCNA and GO functional enrichment analyses revealed that genes related to cell division and chondrocyte differentiation were up-regulated, whereas those with steroid hormone-mediated signaling pathways were down-regulated at ossification stages. Additionally, 25 tumor suppressor genes and 11 oncogenes were identified and were predicted to interact with p53. Co-regulation of tumor suppressor genes and oncogenes is responsible for the special growth pattern of antlers. Together, we constructed the most complete sika deer antler transcriptome database so far. The database provides data support for subsequent studies on the molecular mechanism of sika deer antler chondrogenesis and osteogenesis.

Complete mitochondrial genome and phylogenetic analysis of eight sika deer subspecies in northeast Asia.

Sika deer (Cervus nippon) are large ruminants distributed throughout northeastern Asia. The phylogenetic relationship of the sika deer subspecies remains unclear. The complete mitochondrial genomes of 287 sika deer from eight subspecies (C. n. hortulorum, C. n. sichuanicus, C. n. kopschi, C. n. taiouanus, C. n. yesoensis, C. n. centralis, C. n. nippon and C. n. yakushimae) were obtained. Haplotype network and development of a phylogenetic tree revealed China clusters and Japan clusters that were well separated based on the mitochondrial whole-genome level. Our studies indicate that China sika deer are genetically distinguishable from Japanese samples. Our findings increase the understanding of the phylogenetic relationships of sika deer and could provide useful information for sika deer conservation projects as well as for sika deer genomics, emergence and geographical distribution.

Development and validation of a 1 K sika deer (Cervus nippon) SNP Chip.

BACKGROUND: China is the birthplace of the deer family and the country with the most abundant deer resources. However, at present, China's deer industry faces the problem that pure sika deer and hybrid deer cannot be easily distinguished. Therefore, the development of a SNP identification chip is urgently required. RESULTS: In this study, 250 sika deer, 206 red deer, 23 first-generation hybrid deer (F1), 20 s-generation hybrid deer (F2), and 20 third-generation hybrid deer (F3) were resequenced. Using the chromosome-level sika deer genome as the reference sequence, mutation detection was performed on all individuals, and a total of 130,306,923 SNP loci were generated. After quality control filtering was performed, the remaining 31,140,900 loci were confirmed. From molecular-level and morphological analyses, the sika deer reference population and the red deer reference population were established. The Fst values of all SNPs in the two reference populations were calculated. According to customized algorithms and strict screening principles, 1000 red deer-specific SNP sites were finally selected for chip design, and 63 hybrid individuals were determined to contain red deer-specific SNP loci. The results showed that the gene content of red deer gradually decreased in subsequent hybrid generations, and this decrease roughly conformed to the law of statistical genetics. Reaction probes were designed according to the screening sites. All candidate sites met the requirements of the Illumina chip scoring system. The average score was 0.99, and the MAF was in the range of 0.3277 to 0.3621. Furthermore, 266 deer (125 sika deer, 39 red deer, 56 F1, 29 F2,17 F3) were randomly selected for 1 K SNP chip verification. The results showed that among the 1000 SNP sites, 995 probes were synthesized, 4 of which could not be typed, while 973 loci were polymorphic. PCA, random forest and ADMIXTURE results showed that the 1 K sika deer SNP chip was able to clearly distinguish sika deer, red deer, and hybrid deer and that this 1 K SNP chip technology may provide technical support for the protection and utilization of pure sika deer species resources. CONCLUSION: We successfully developed a low-density identification chip that can quickly and accurately distinguish sika deer from their hybrid offspring, thereby providing technical support for the protection and utilization of pure sika deer germplasm resources.

Genetic diversity of Aoluguya Reindeer based on D-loop region of mtDNA and its conservation implications.

Aoluguya Reindeer is the only reindeer population in China. In recent years, habitat loss and inbreeding have led to population decline, and population growth has been slow, maintaining a thousand or so. To better protect the Aoluguya Reindeer and improve its fecundity, we have introduced reindeer from Finland, crossbreeding help us to reach this goal. However, it is lacking in the study of genetic diversity of reindeer in China and Finland. Therefore, we used the partial sequences of the D-loop region of mitochondrial DNA to analyze the genetic diversity of Chinese reindeer (Aoluguya Reindeer) and the introduced Finnish reindeer, and identified twenty-six haplotypes, including nineteen in China, five in Finland, and two in Russia. There is no shared haplotype among them. The nucleotide diversity of Aoluguya Reindeer is 0.00752, which is significantly lower than that of reindeer in Finland and other countries. The haplotype and phylogenetic analysis show that reindeer from different geographical origins are not clustered completely according to geographical distribution. Aoluguya Reindeer populations and the introduced reindeer herds from Finland are all closely related to the reindeer from Russia. AMOVA analysis showed that there was significant differentiation between reindeer populations in China and Finland, and mismatch analysis showed that both populations had not experienced expansion. In this study, we identified the genetic diversity of Aoluguya Reindeer and the introduced reindeer, and provided a scientific basis for the conservation and breeding of Aoluguya Reindeer resources.

Genetic diversity and population genetic structure of the only population of Aoluguya Reindeer (Rangifer tarandus) in China.

Aoluguya Reindeer is the only reindeer species in China and currently approximately 1000 Aoluguya Reindeer remain semi-domesticated. A relative low diversity estimate was found by investigating genetic variability and demographic history of its population. Mismatch distribution curve of its nucleotide sequences and neutral test indicate its population has not experienced expansion. Genetic diversity and population structure were also analysed by using its mtDNA and microsatellites technology. Statistical results of these analyses showed there were varying degrees of population inbreeding and suggested that gene flow existed among its populations at one time. Three mutation models were also used to detect the bottleneck effect of reindeer population. The genetic variation of eight populations is relatively small. In addition, the clustering program STRUCTURE was used to analyse Aoluguya Reindeer population structure, to determine its optimal K and first time to analyse the phylogenetic status of Aoluguya Reindeer among other reindeer subspecies. It is recommended that the government establish a natural conservation area in Aoluguya Reindeer growing geography, forbade the trade and hunting of Aoluguya Reindeer, and strengthen the protection of this endangered species.

Screening weight related genes of velvet antlers by whole genome re-sequencing.

The velvet antler is a special organ that has important biological significance for deer, and its growth is a complicated biological metabolism process. Growing evidence suggests that genetics factors play essential roles in the weight of velvet antlers. In this study, we investigated five sika deer (Cervus nippon) populations under the same feeding condition, and screened genetic variations in the 100 samples (including 50 heavy and 50 light velvet antler weight samples) by whole genome re-sequencing. The results showed that 94 genetic variations were related to the velvet antler weight, among which two single nucleotide polymorphism (SNP) sites were located on the exon regions of OAS2 and ALYREF/THOC4, respectively. Furthermore, ALYREF/THOC4 is highly expressed in the velvet antler. The biological functions of these genetic variations were highly related to the growth and development of deer velvet antlers. Collectively, we screened genes related to the velvet antler weight in sika deer populations by whole genome re-sequencing and identified 94 sites as candidate genetic variations related to the velvet antler weight. We hope that it will contribute to further mechanistic studies of velvet antler development and weight variations.

Content modification attacks on consensus seeking multi-agent system with double-integrator dynamics.

In this paper, vulnerability of a distributed consensus seeking multi-agent system (MAS) with double-integrator dynamics against edge-bound content modification cyber attacks is studied. In particular, we define a specific edge-bound content modification cyber attack called malignant content modification attack (MCoMA), which results in unbounded growth of an appropriately defined group disagreement vector. Properties of MCoMA are utilized to design detection and mitigation algorithms so as to impart resilience in the considered MAS against MCoMA. Additionally, the proposed detection mechanism is extended to detect the general edge-bound content modification attacks (not just MCoMA). Finally, the efficacies of the proposed results are illustrated through numerical simulations.