Human amylin induces CD4+Foxp3+ regulatory T cells in the protection from autoimmune diabetes.

Autoimmune diabetes is a disorder of immune homeostasis that leads to targeted insulin-secreting islet ß cell destruction characterized by insulitis. Human amylin (hA) is an important neuroendocrine hormone co-secreted with insulin by pancreatic ß cells. Here, we report hA immune-modulatory action through inducing regulatory T cells. We ex vivo-treated human peripheral blood mononuclear cells (hPBMCs) with hA for 24 h and counted CD4+Foxp3+ regulatory T cells (Treg) using flow cytometry. Diabetic status was monitored and splenic Treg were measured in non-obese diabetic (NOD) male mice. NOD mice were intraperitoneally injected once daily with hA (n = 25) or solvent for control (n = 25) for 7 months continuously. Spleen tissues were collected at the end of intervention and processed for flow cytometry and Western blot. We found a 2.9-fold (p < 0.05) increase of CD4+Foxp3+ Treg in hPBMCs treated with 10 nmol/L hA compared with negative control. Incidence of diabetes in hA-treated NOD mice decreased 44% (p = 0.045) in the 6th month and 57% (p = 0.0002) in the 7th month. Meanwhile, the hA treatment induced a 1.5-fold increase of CD4+Foxp3+ Treg from mouse splenocytes (p = 0.0013). Expression of transforming growth factor-ß (TGF-ß) and toll-like receptor-4 (TLR-4) were upregulated in hA-treated mice. Human amylin might protect against autoimmune diabetes via the induction of CD4+Foxp3+ Treg, which suggests a novel approach to improve autoimmune conditions.

Expression of germline markers in three species of amphioxus supports a preformation mechanism of germ cell development in cephalochordates.

BACKGROUND: In a previous study, we showed that the cephalochordate amphioxus Branchiostoma floridae has localized maternal transcripts of conserved germ cell markers Vasa and Nanos in its early embryos. These results provided strong evidence to support a preformation mechanism for primordial germ cell (PGC) development in B. floridae. RESULTS: In this study, we further characterize the expression of B. floridae homologs of Piwi and Tudor, which play important roles in germline development in diverse metazoan animals. We show that maternal mRNA of one of the identified Piwi-like homologs, Bf-Piwil1, also colocalizes with Vasa in the vegetal germ plasm and has zygotic expression in both the putative PGCs and the tail bud, suggesting it may function in both germline and somatic stem cells. More interestingly, one Tudor family gene, Bf-Tdrd7, is only expressed maternally and colocalizes with Vasa in germ plasm, suggesting that it may function exclusively in germ cell specification. To evaluate the conservation of the preformation mechanism among amphioxus species, we further analyze Vasa, Nanos, Piwil1, and Tdrd7 expression in two Asian amphioxus species, B. belcheri and B. japonicum. Their maternal transcripts all localize in similar patterns to those seen in B. floridae. In addition, we labeled putative PGCs with Vasa antibody to trace their dynamic distribution in developing larvae. CONCLUSIONS: We identify additional germ plasm components in amphioxus and demonstrate the molecular distinction between the putative germline stem cells and somatic stem cells. Moreover, our results suggest that preformation may be a conserved mechanism for PGC specification among Branchiostoma species. Our Vasa antibody staining results suggest that after the late neurula stage, amphioxus PGCs probably proliferate with the tail bud cells during posterior elongation and are deposited near the forming myomere boundaries. Subsequently, these PGCs would concentrate at the ventral tip of the myoseptal walls to form the gonad anlagen.

Characterization and expression of AmphiBMP3 /3b gene in amphioxus Branchiostoma japonicum.

Bone morphogenetic proteins (BMPs) are responsible for regulating embryo development and tissue homeostasis beyond osteogenesis. However, the precise biological roles of BMP3 and BMP3b remain obscure to a certain extent. In the present study, we cloned an orthologous gene (AmphiBMP3/3b) from amphioxus (Branchiostoma japonicum) and found its exon/intron organization is highly conserved. Further, in situ hybridization revealed that the gene was strongly expressed in the dorsal neural plate of the embryos. The gene also appeared in Hatschek's left diverticulum, neural tube, preoral ciliated pit and gill slit of larvae, and adult tissues including ovary, neural tube and notochordal sheath. Additionally, real-time quantitative polymerase chain reaction (RTqPCR) analysis revealed that the expression displayed two peaks at gastrula and juvenile stages. These results indicated that AmphiBMP3/3b, a sole orthologue of vertebrate BMP3 and BMP3b, might antagonize ventralizing BMP2 orthologous signaling in embryonic development, play a role in the evolutionary precursors of adenohypophysis, as well as act in female ovary physiology in adult.

Evolutionary and functional diversity of green fluorescent proteins in cephalochordates.

Green fluorescent protein (GFP) has been widely used as a molecular marker in modern biological research. Before the recent report of one GFP gene in Branchiostoma floridae, GFP family members were cloned only from other two groups of species: Cnidaria and Copepoda. Here we describe the complete GFP gene repertoire of B. floridae which includes 13 functional genes and 2 pseudogenes, representing the largest GFP family found so far. Coupling with nine other GFP sequences from another two species of genus Branchiostoma and the sequences from Cnidaria and Copepoda, we made a deep-level phylogenetic analysis for GFP genes in cephalochordates and found: 1) GFP genes have experienced a divergent evolution in cephalochordates; 2) all amphioxus GFP genes form four main clades on the tree which had diverged before the radiation of the last common ancestor of all extant cephalochordates; 3) GFP genes in amphioxus shared a common ancestor with that in Copepoda rather than being derived from horizontal gene transfer, which indicates that our ancestor was derived from a fluorescent organism and lost this ability after its separation from Cephalochordata, and also makes GFP a rare gene which has a rather unusual evolutionary path. In addition, we also provided evidence indicating that GFP genes have evolved divergent functions by specializing their expression profile, and different fluorescent spectra by changing their emission peaks. These findings spark two interesting issues: what are GFP in vivo functions in cephalochordates and why they are lost in other examined deuterostomes?

Origin and evolution of vertebrate ABCA genes: a story from amphioxus.

Previous studies showed that the vertebrate ABCA subfamily, one subgroup of the ATP-binding-cassette superfamily, has evolved rapidly in terms of gene duplication and loss. To further uncover the evolutionary history of the ABCA subfamily, we characterized ABCA members of two amphioxus species (Branchiostoma floridae and B. belcheri), the closest living invertebrate relative to vertebrates. Phylogenetic analysis indicated that these two species have the same set of ABCA genes (both containing six members). Five of these genes have clear orthologs in vertebrate, including one cephalochordate-specific duplication and one vertebrate-specific duplication. In addition, it is found that human orthologs of amphioxus ABCA1/4/7 and its neighboring genes mainly localize on chromosome 1, 9, 19 and 5. Considering that most of analyzed amphioxus genes have clear orthologs in zebrafish, we conclude these four human paralogous regions might derive from a common ancestral region by genome duplication occurred prior to teleost/tetrapod split. Therefore, the present results provide new evidence for 2R hypothesis.

Continuous culture of two lancelets and production of the second filial generations in the laboratory.

The lancelet is considered to be a promising laboratory model animal. To establish laboratory colonies of lancelet, we collected parental lancelets of Branchiostoma belcheri and B. japonicum (previously named as B. belcheri tsingtauense) with fully developed gonads from Xiamen Rare Marine Creature Conservation Areas (Fujian, China) on dates just before their spawning in the field in 2005. Those parental lancelets spawned spontaneously in the laboratory and produced thousands upon thousands of fertilized eggs. After carefully hatching and maintaining for almost 1 year, we successfully obtained about 500 first generation (F1) adults of B. belcheri and 3,300 of B. japonicum. Part of those F1 lancelets ripened and spontaneously spawned in 2006, and several thousands of second generation (F2) individuals of both species were produced. The young F2 lancelets are growing in good condition and some of B. japonicum initiated gonad development in December, 2006. Our experience emphasizes that cleanness of settlement substratum and sufficient food supply are important factors for long-term culture of lancelets in the laboratory.

Branchiostoma japonicum and B. belcheri are distinct lancelets (Cephalochordata) in Xiamen waters in China.

Lancelets in Xiamen were reported as Branchiostoma belcheri in 1932, and subsequently were believed to comprise a single species. However, recent studies revealed that Xiamen lancelets actually represent two species, B. belcheri and B. japonicum. We observed thousands of lancelets from Xiamen beach to recognize these two species. Our observations showed that at least three morphological characters distinguish them: 1) the rostral fin is slightly round with the end obtuse in B. belcheri but elliptic with the end cuspate in B. japonicum; 2) the number of preanal fin-chambers is more than 80 in B. belcheri but less than 64 in B. japonicum, and the chambers are slender in the former but stout in the latter; 3) the caudal fin of B. belcheri is narrower than that of B. japonicum, and the angle between the dorsal and super-caudal fins, and between preanal and sub-caudal fins, is obtuse in B. belcheri but acute in B. japonicum. We also provide some ecological and distributional evidence to support the conclusion that there are two separate species in Xiamen waters.

[Effects of combined naloxone and methylprednisolone on nuclear factor-kappaB expression in the lung in acute lung injury in rats].

OBJECTIVE: To investigate the effects of a combination of naloxone and methylprednisolone on nuclear factor-kappaB (NF-kappaB) p65 expression in the lung tissue in lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. METHODS: ALI models were reproduced by intratracheal instillation of LPS (3 mg/kg). Four hours after LPS instillation, rats were randomly divided into five groups: normal saline group, LPS group, methylprednisolone group, naloxone group (LPS+naloxone) and combined drug group (LPS+naloxone+methylprednisolone). The level of interleukin-8 (IL-8) in serum was measured by immunoassay. Meanwhile, the expression of NF-kappaB p65 in the lung tissue was determined with immunohistochemical staining. RESULTS: Naloxone and methylprednisolone significantly reduced the LPS-induced increase in IL-8 concentrations in serum in vivo, and suppressed the activation of NF-kappaB p65 in the lung tissue. CONCLUSION: NF-kappaB activation is involved in the LPS-induced ALI in rats. Combination of naloxone and methylprednisolone could suppress the increase of IL-8 content and NF-kappaB activation in the lung tissue of rat in vivo in our experiment.