Molecular evolution and gene expression of ferritin family involved in immune defense of lampreys.

Ferritin, one of the key regulators of iron homeostasis, is widely present throughout almost all species. The vertebrate ferritin family, which originates from a single gene in the ancestral invertebrates, contains the widest variety of ferritin subtypes among all animal species. However, the evolutionary history of the vertebrate ferritin family remains to be further clarified. In this study, genome-wide identification of the ferritin homologs is performed in lampreys, which are the extant representatives of jawless vertebrates that diverged from the future jawed vertebrates more than 500 million years ago. Molecular evolutionary analyses show that four members of the lamprey ferritin family, L-FT1-4, are derived from a common ancestor with jawed vertebrate ferritins prior to the divergence of the jawed vertebrate ferritin subtypes. The lamprey ferritin family shares evolutionarily conserved characteristics of the ferritin H subunit with higher vertebrates, but certain members such as L-FT1 additionally accumulate some features of the M or L subunits. Expression profiling reveals that lamprey ferritins are highly expressed in the liver. The transcription of L-FT1 is significantly induced in the liver and heart during lipopolysaccharide stimulation, indicating that L-FTs may play a role in the innate immune response to bacterial infection in lampreys. Furthermore, the transcriptional expression of L-FT1 in quiescent and LPS-activated leukocytes is up- and down-regulated by the lamprey TGF-ß2, an essential regulator of the inflammatory response, respectively. Our results provide new insights into the origin and evolution of the vertebrate ferritin family and reveal that lamprey ferritins may be involved in immune regulation as target genes of the TGF-ß signaling pathway.

Protective limb remote ischemic post-conditioning against high-intraocular-pressure-induced retinal injury in mice.

AIM: To determine whether limb remote ischemic post-conditioning (LRIC) protects against high-intraocular-pressure (IOP)-induced retinal injury, and to identify underlying molecular mechanisms. METHODS: In mice, IOP was increased to 110 mm Hg for 50min and LRIC applied to the unilateral leg for three occlusion cycles (5min/release). Three animal groups (control, high IOP, and high IOP+LRIC) were arranged in this study. Plasma was collected from LRIC treated mice. Retinal histology, oxidative stress were determined by histological section staining and chemical kit. C/EBP homologous protein (CHOP), and Iba-1 parameters were evaluated by immunofluorescent staining and Western blot. RESULTS: The data showed that LRIC treatment alleviated the retinal histological disorganization and ganglion cell loss induced by high IOP. The CHOP, Iba-1 expression and oxidative stress marker also were inhibited by LRIC treatment. To further explore underlying mechanisms, plasma from LRIC treated animals was intravenously transfused into high-IOP animals. The results showed plasma injection decreased caspase 9 expression and DHE staining signals compared with that in high IOP retinas. CONCLUSION: These data suggest that LRIC treatments exert retinal protective effects against high-IOP injury. Endogenous humoral factors release into the circulation by LRIC may contribute to homeostatic protection by reducing monocyte infiltration and/or microglia activation.

Molecular Evolution of Transforming Growth Factor-ß (TGF-ß) Gene Family and the Functional Characterization of Lamprey TGF-ß2.

The transforming growth factor-ßs (TGF-ßs) are multifunctional cytokines capable of regulating a wide range of cellular behaviors and play a key role in maintaining the homeostasis of the immune system. The TGF-ß subfamily, which is only present in deuterostomes, expands from a single gene in invertebrates to multiple members in jawed vertebrates. However, the evolutionary processes of the TGF-ß subfamily in vertebrates still lack sufficient elucidation. In this study, the TGF-ß homologs are identified at the genome-wide level in the reissner lamprey (Lethenteron reissneri), the sea lamprey (Petromyzon marinus), and the Japanese lamprey (Lampetra japonica), which are the extant representatives of jawless vertebrates with a history of more than 350 million years. The molecular evolutionary analyses reveal that the lamprey TGF-ß subfamily contains two members representing ancestors of TGF-ß2 and 3 in vertebrates, respectively, but TGF-ß1 is absent. The transcriptional expression patterns show that the lamprey TGF-ß2 may play a central regulatory role in the innate immune response of the lamprey since it exhibits a more rapid and significant upregulation of expression than TGF-ß3 during lipopolysaccharide stimuli. The incorporation of BrdU assay reveals that the lamprey TGF-ß2 recombinant protein exerts the bipolar regulation on the proliferation of the supraneural myeloid body cells (SMB cells) in the quiescent and LPS-activated state, while plays an inhibitory role in the proliferation of quiescent and activated leukocytes in lampreys. Furthermore, caspase-3/7 activity analysis indicates that the lamprey TGF-ß2 protects SMB cells from apoptosis after serum deprivation, in contrast to promoting apoptosis of leukocytes. Our composite results offer valuable clues to the origin and evolution of the TGF-ß subfamily and imply that TGF-ßs are among the most ancestral immune regulators in vertebrates.