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Abstract The evolutionary divergence of the immune defense functions in bighead carp (A. nobilis) and silver carp (H. molitrix) is still not understood at the molecular level. Here, we obtained 48,821,754 and 55,054,480 clean reads from spleen tissue libraries prepared for bighead carp and silver carp using Illumina paired-end sequencing technology, respectively, and identified 4976 orthologous genes from the transcriptome data sets by comparative analysis. Adaptive evolutionary analysis showed that 212 orthologous genes and 255 Gene Ontology (GO) terms were subjected to positive selection(Ka/Ks values > 1) only in bighead carp, and 195 orthologous genes and 309 GO terms only in silver carp. Among immune defense functions with significant evolutionary divergence, the positively selected biological processes in bighead carp mainly included B cell-mediated immunity, chemokine-mediated signaling pathway, and immunoglobulin mediated immune response, whereas those in silver carp mainly included the antigen processing and presentation, defense response to fungus, and detection of bacteria. Moreover, we found 2974 genes expressed only in spleen of bighead carp and 3494 genes expressed only in spleen of silver carp, where these genes were mostly enriched in the same biological processes or pathways. These results provide a better understanding of the differences in resistance to some diseases by bighead carp and silver carp, and also facilitate the identification of candidate genes related to disease resistance. Highlights • We first obtained the spleen transcriptome data of silver carp and bighead carp. • We identified 4976 orthologous genes from spleen transcriptome data of two species. • We found 212 and 195 genes with positive selection in bighead carp and silver carp. • We found spleen adaptive immune evolution has obvious divergence across two species. [ABSTRACT FROM AUTHOR]

Grass carp Ctenopharyngodon idella is an important freshwater aquaculture species. However, studies regarding transcriptomic profiling of developing spleen tissue in the grass carp are lacking. Here, the transcriptome sequencing from the spleen tissue of one-year-old (cis1) and three-year-old (cis3) grass carp was performed using Illumina paired-end sequencing technology. The de novo assemblies yielded 48,970 unigenes with average lengths of 1264.51 bp from the two libraries. The assembled unigenes were evaluated and functionally annotated by comparing with sequences in major public databases including Nr, COG, Swiss-Prot, KEGG, Pfam and GO. Comparative analysis of expression levels revealed that a total of 38,254 unigenes were expressed in both the cis1 and cis3 libraries, while 4356 unigenes were expressed only in the cis1 library, and 3312 unigenes were expressed only in the cis3 library. Meanwhile, 1782 unigenes (including 903 down-regulated and 879 up-regulated unigenes) were differentially expressed between the two developmental stages of the grass carp spleen. Based on GO and KEGG enrichment analysis, these differentially expressed genes widely participated in the regulation of immunity and response in the grass carp. Moreover, the main components of six immune-related pathways were identified, including complement and coagulation cascades, Toll-like receptor signaling, B-cell receptor signaling, T-cell receptor signaling, antigen processing and presentation, and chemokine signaling. Finally, two identified transcripts including TLR 8 and complement component C8 were validated for reliability by RT-PCR. Collectively, the results obtained in this study will provide a basis for the study of molecular mechanisms in grass carp spleen development. [ABSTRACT FROM AUTHOR]

Common carp ( Cyprinus carpio ) is one of the most important aquacultured species of the family Cyprinidae , and breeding this species for disease resistance is becoming more and more important. However, at the genome or transcriptome levels, study of the immunogenetics of disease resistance in the common carp is lacking. In this study, 60,316,906 and 75,200,328 paired-end clean reads were obtained from two cDNA libraries of the common carp spleen by Illumina paired-end sequencing technology. Totally, 130,293 unique transcript fragments (unigenes) were assembled, with an average length of 1400.57 bp. Approximately 105,612 (81.06%) unigenes could be annotated according to their homology with matches in the Nr, Nt, Swiss–Prot, COG, GO, or KEGG databases, and they were found to represent 46,747 non-redundant genes. Comparative analysis showed that 59.82% of the unigenes have significant similarity to zebrafish Refseq proteins. Gene expression comparison revealed that 10,432 and 6889 annotated unigenes were, respectively, up- and down-regulated with at least twofold changes between two developmental stages of the common carp spleen. Gene ontology and KEGG analysis were performed to classify all unigenes into functional categories for understanding gene functions and regulation pathways. In addition, 46,847 simple sequence repeats (SSRs) were detected from 35,618 unigenes, and a large number of single nucleotide polymorphism (SNP) and insertion/deletion (INDEL) sites were identified in the spleen transcriptome of common carp. This study has characterized the spleen transcriptome of the common carp for the first time, providing a valuable resource for a better understanding of the common carp immune system and defense mechanisms. This knowledge will also facilitate future functional studies on common carp immunogenetics that may eventually be applied in breeding programs. [ABSTRACT FROM AUTHOR]

Immune defense functions of silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis) have shown obvious evolutionary divergence. MiRNAs participate in the fine regulation of immune function. However, the evolutionary adaptation of miRNAs in the regulation of immune defense function is still poorly understood in silver carp and bighead carp. Here, small RNA libraries were constructed from the spleen tissue of one-year-old and three-year-old healthy silver carp and bighead carp, 424 and 422 known conserved miRNAs were respectively identified from the spleen of silver carp and bighead carp by bioinformatic analysis, which 398 were shared between the two species. These conserved miRNAs showed highly similar expression patterns between silver carp and bighead carp, but the abundance in spleen varied greatly in different species. Family analysis showed that miRNA families including mir-8, mir-7, mir-23, mir-338, mir-30, mir-27, mir-221, mir-19, mir-181, mir-17, mir-15, mir-148, mir-130, mir-10 and let-7 were the main miRNAs in the spleen of silver carp and bighead carp. 27 and 51 significant differentially expressed (SDE) miRNAs were identified from silver carp and bighead carp, respectively. Evolution analysis for the predicted target genes of SDE-miRNAs showed that ten biological processes such as blood coagulation, cell adhesion mediated by integrin and adaptive immune response were positively selected. In addition, immune genes including TLR3 , NFATC3 , MALT1 , B2M , GILT and MHCII were positively selected only in silver carp, and they were specifically targeted by the SDE-miRNAs including miR-9-5p, miR-196a-5p, miR-375, miR-122, miR-722, miR-132-3p, miR-727-5p, miR-724, miR-19d-5p and miR-138-5p, respectively. PLA2G4 in Fc epsilon RI signaling pathway was positively selected only in bighead carp and was specifically targeted by the SDE-miRNAs including miR-222b, miR-22b-5p, miR-15c, miR-146a, miR-125c-3p, miR-221-5p, miR-2188-5p, miR-142a-3p, miR-212, miR-138-5p and miR-15b-5p. In particular, SDE-miRNAs such as miR-144-3p, miR-2188-3p, miR-731, miR-363-3p and miR-218b could simultaneously target multiple evolutionarily differentiated immune-related genes. These results indicated that in the spleen of silver carp and bighead carp, conserved miRNAs have obvious evolutionary adaptations in the regulation of immune defense function. The results of this study can provide valuable resources for further revealing themechanism of miRNA in the formation of resistance traits evolution between silver carp and bighead carp. • We described characteristics of conserved microRNAome in spleen of silver carp and bighead carp. • We found highly similar expression patterns of splenic conserved miRNAs between the two species. • We identified 27 and 51 SDE miRNA from the spleen of silver carp and bighead carp, respectively. • We found significant evolutionary adaptation of SDE miRNA in regulation of spleen immune function. • We found 7 key immune gene and their interaction miRNA in regulation of evolutionary divergence. [ABSTRACT FROM AUTHOR]

Congenital generalized lipodystrophy 2 (CGL2) is characterized by loss of adipose tissue, insulin resistance and cognitive deficits and caused by mutation of BSCL2/seipin gene. Seipin deletion in mice and rats causes severe lipodystrophy, insulin resistance, and cognitive impairment. Hippocampal neurons express seipin protein. This study aimed to investigate the influence of systemic seipin knockout (seipin -sKO), neuronal seipin knockout (seipin -nKO) or adipose seipin knockout (seipin -aKO) in hippocampal tau phosphorylation and aggregation. Levels of tau phosphorylation at Thr212/Ser214 and Ser202/Thr205 and oligomer tau protein were increased in seipin -sKO mice and seipin -nKO mice with a decrease in axonal density and expression of PPARγ. Neuronal seipin deletion increased activities of GSK3β and Akt/mTOR signaling, which were corrected by the administration of PPARγ agonist rosiglitazone for 7 days. The autophagosome formation was reduced in seipin -sKO mice and seipin -nKO mice, which was rescued by the Akt and mTOR inhibitors. The administration of rosiglitazone or Akt, mTOR and GSK3β inhibitors for 7 days could correct the hyperphosphorylation and aggregation of tau. On the other hand, seipin -sKO mice appeared insulin resistance and an increase in phosphorylation of tau at Ser396 and JNK, which were corrected by treatment with rosiglitazone for 30 days rather than 7 days. Inhibition of JNK in seipin -sKO mice corrected the hyperphosphorylated tau at Ser396. The results indicate that neuronal seipin deletion causes hyperphosphorylation and aggregation of tau protein leading to axonal atrophy through reduced PPARγ to enhance GSK3β and Akt/mTOR signaling; systemic seipin deletion-induced insulin resistance causes tau hyperphosphorylation via cascading JNK pathway. • Seipin deletion enhances tau phosphorylation and aggregation, and axonal atrophy. • Seipin deletion via reducing PPARγ increases Akt-mTOR activity to suppress autophagy. • Decline of PPARγ increases tau phosphorylation through elevated GSK3β activity. • Insulin resistance by lacking seipin enhances tau phosphorylation via JNK activation. [ABSTRACT FROM AUTHOR]