Abstract:There is a growing interest for epigenetics in recent years. The main patterns of epigenetic regulation include DNA methylation, histone modification and chromatin remodeling, etc. The outcome of ENCODE project and subsequent studies have revealed that only a small portion of human genome encodes proteins, while the vast majority are transcribed as non-coding RNA (ncRNA). Long non-coding RNA (lncRNA) is commonly defined as an RNA molecule which is larger than 200 nucleotides (nt) and not translated into proteins. Growing evidences have suggested that lncRNAs can regulate gene expression at various levels including epigenetic regulation, transcriptional regulation and post-transcriptional regulation, and are involved in a wide variety of biological processes, such as cell proliferation, differentiation and apoptosis. In this review, we highlight the recent advances of how lncRNAs function in the epigenetic regulation.

Abstract:Cell penetrating peptide (CPP) is a kind of small peptide with the capability of penetrating through cell membrane, which provides efficient tools for achieving intracellular access for macromolecular drugs. At present, it has obtained widespread attention and extensive research. Although it has been found recently that many problems hinder the process of its application research and development, such as drug release rate, metabolic degradation, cell lines and differentiation status and Rho GTPases activity dependence，lots of progress has been made in the research of CPPs in cancer treatment, antibacterial and anti-inflammatory targeted drugs, some of which even has entered the stage of preclinical and clinical research. In this article, we focus on two aspects, the challenges and new opportunities in the studies of CPP application, to summarize the recent research progress, and highlight the prospect of new fields of CPP application in the future.

Abstract:Gold nanorods have surface plasmon resonance (SPR) effect and own longitudinal plasmon resonance absorbtion (LSPR) peaks which can be tuned between visible and near infrared (NIR) zones. Moreover, because of SPR effect, gold nanorods also have photothermal effects which can transfer the energy absorbed from light into heat. And NIR light can penetrate into biological tissue with minimal lateral invasion. Therefore, gold nanorods are promising in the biomedical applications such as imaging, photothermal therapy and drug delivery and all of these applications can be controlled remotely by NIR light. And gold nanorods can integrate these functions into one platform, which can realize the combination of diagnosis and therapy, namely theranostics. This review introduces the basic properties of gold nanorods, summarizes three methods of surface modification, review the applications in two-photon fluorescence imaging, photoacoustic tomography imaging, optical coherence tomography imaging, X-Ray computed tomography imaging, photothermal therapy and drug delivery, and highlights latest progresses in application of theranostics.

Abstract:Autism spectrum disorders (ASD) is a widely developmental disabilities, with the main clinical features including barriers to social interaction, verbal and non-verbal communication defects, narrow interests and stereotyped behaviors. The present article aims to introduce some information about language impairment of autism, including relative researches published from 1986 to the current time on the neural mechanisms underlying autism's language impairment. This issue was addressed from brain structural, brain functional asymmetry, and the influence of handness, and at last, a summary was given based on the literatures, which is that the autism has an atypical right language lateralization both of structural and functional, there also exist available evidence that atypical handness is associated with poorer neurocognition or anomalous cerebral asymmetries. This article will be helpful for diagnosis and therapy to the autism in the future and will facilitate the research of ASDs under Chinese culture.

Abstract:Selenoprotien W (SelW) is an important selenoprotein that has the priority to be stored in brain when selenium is deficiency. However, the biological function and mechanisms of SelW in brain remain unclear. In this study, human SelW gene was cloned, site-directedly mutated and inserted into the "bait" plasmid. An interactive protein of SelW, prosaposin (PSAP), was discovered by screening the human fetal brain cDNA library using the yeast two-hybrid system. To verify the protein-protein interaction, two FRET methods, sensitized emission and acceptor bleaching, were performed respectively in HEK293T cells. Both assays confirmed the interaction between SelW′ and PSAP. Then the expression vector of SelW′ was constructed and SelW was overexpressed in E. coli. Pull-down assay was carried out by using the purified SelW′, and exogenously direct interaction between SelW′ and PSAP was also verified. Finally, co-IP method was applied to successfully verify the endogenous interaction between the two proteins in the brain tissues of Kunming mice. All these results show that SelW interacts with PSAP directly both in vivo and in vitro. SelW may play a key role in the brain development and neurodegenerative disease formation by interacting with PASP.

Abstract:The brain is the most cholesterol-rich organ in the body and consists of 25% of total cholesterol. ATP-binding cassette (ABC) transporters play essential roles in cellular cholesterol efflux and homeostasis in the brain. Recently, ABCG1, ABCG4 and ABCA1 expression in the adult brain has been described. The absence of one or more of these transporters has been implicated in the development of neurodegenerative diseases. In this study, we characterized the mRNA and protein expression levels of ABCG1, ABCG4 and ABCA1 in the developing postnatal brain of normal C57BL/6J mice fed a chow diet. We studied the correlation between ABC transporters expression and cholesterol levels (free cholesterol, esterified cholesterol) in the brain and serum, to elucidate a potential role of these transporters in cholesterol metabolism in the brain and body during postnatal stages. We further investigated the changes of expression levels of ABCG1, ABCG4, ABCA1, cholesterol related genes and brain cholesterol levels in ABCG1-/-, ABCG4-/- and ABCG1-/- ABCG4-/- double knockout mice. ABCA1 mRNA expression were detectable in multiple tissues, and ABCG1, ABCG4 were highly expressed in adult brain. ABCG1 and ABCG4 mRNA levels peaked at 42 days of age, while ABCA1 mRNA levels were near baseline. ABCG1 protein levels peaked at day 28 then decreased, while ABCG4 levels peaked at day 42. ABCA1 levels remained near baseline. Interestingly, circulating plasma and brain esterified cholesterol levels exhibited a biphasic distribution, which peaked at day 42. Loss of ABCG1 is compensated by increased ABCG4 and vice versa. Loss of both ABCG1 and ABCG4 results in altered expression of cholesterol synthesis related genes and cholesterol accumulation in the brain. The data suggest that ABCG1 and ABCG4, but not ABCA1 are important for transporter function in the developing brain. ABCG1 and ABCG4 play complementary roles in maintaining brain cholesterol homeostasis.

Abstract:E. coli is well studied in fatty acid synthesisⅡ. FabA, a bifunctional enzyme, is the key enzyme of the classic anaerobic pathway of unsaturated fatty acid synthesis. Sequence alignments indicated that Lactococcus lactis lacks homologues of E. coli FabA, however it owns two homologues of E. coli FabZ, LlfabZ1 and LlfabZ2. LlFabZ1 and LlFabZ1 are 41% and 45.1% identical to E. coli FabZ, respectively. Further analysis showed that the conservative active-site in E. coli FabZ is also found in LlFabZ1 and LlFabZ1. Although the genetic complementary revealed that LlfabZ1 and LlfabZ2 were not able to restore the growth and the fatty acid synthesis of the E. coli temperature sensitive mutant CY57 at nonpermissive temperature, cell-free extract data showed LlFabZ1 was able to catalyze the isomerization of the trans-2-double bond to the cis-3 species. Moreover, LlfabZ2 was able to complement the EcfabZ knock out mutant HW7. In vitro assay identified that LlFabZ1 was able to introduce the cis double bond into a 10-carbon intermediate, and LlFabZ2 was able to dehydrated 3-hydroxyacyl-ACP to trans-2-decenoy-ACP. However, we also attempted to inactivate the fabZ1 and fabZ2 genes by allelic replacement but none of the fabZ1 and fabZ2 deletion mutant was obtained, and it seemed likely that fabZ1 and fabZ2 are essential genes in L. lactis. These results demonstrated that LlFabZ1 and LlFabZ2 are key enzymes in fatty acid synthesis in L. lactis.

Abstract:The dense core vesicle (DCV) is a key organelle involved in the secretion of hormones and neuropeptides in endocrine cells and neurons in response to stimulation. However, the mechanisms underlying its biogenesis, trafficking and exocytosis remain largely unknown. In this study, to discover novel players functioning in DCV secretion, we performed a genome-wide RNAi screen in C. elegans by observing worm defecation behavior. A series of genes that function in the intestine to regulate DCV biogenesis or exocytosis were successfully identified, including CAB-1, which was further determined to be a specific regulator for DCV exocytosis. In the intestine, cab-1 mutation causes reduced secretion of intestinal DCV cargoes. In the nervous system, the loss of CAB-1 leads to the accumulation of DCV markers in the presynaptic region, but synaptic vesicles are not affected. This work demonstrates that CAB-1 is a regulatory factor specifically involved in DCV secretion.

Abstract:Sarco-endoplasmic reticulum calcium transporting ATPase expressed in adult fast-twitch skeletal muscle (SERCA1a) utilizes energy from ATP hydrolysis to transport Ca²⁺ from cytoplasm into sarcoplasmic reticulum against the Ca² concentration gradient. By this means, the Ca² concentration in cytoplasm may decrease and contracted muscle cells relax. SERCA1a is the structurally and functionally best studied representative of the P-type ion transporting ATPase. Studies of SERCA1a may provide with enlightening information for research about other SERCA isoforms and P type ATPase. To understand the functional roles of the linker between the transmembrane helix M7 and the transmembrane helix M8 (L78), mutational studies about some L78 amino acid residues were performed to evaluate the effect of their single substitutions on the SERCA1a reaction cycle. Mutant SERCA1a cDNAs were obtained by Quick Change site directed mutagenesis. SERCA1a wild type and mutant proteins were expressed in COS-1 cells separately and extracted by microsome preparation. Single mutant SERCA1a proteins, wild type SERCA1a proteins and control microsomes were checked with radioactive [γ-³²P]ATP, ⁴⁵CaCl₂, and ³²Pi independently to determine their ATPase activities, Ca² transport rates, amount of total EP formed from ATP, and amount of E2P formed from Pi. Results showed that all single mutants except for G864A transported Ca² at lower rates than that of the SERCA1a wild type protein. Single mutations of G862 or P863 lead to severe decreases of the ATPase activity and the amount of EP formed from ATP or Pi. Measurements about ATP hydrolysis and EP formation of A893P gavde ata similar to those obtained from G⁸⁶² P⁸⁶³ single mutant proteins, whereas single mutants of G864 and FMQ873-875 did not induce significant reduction of ATPase activity and EP amount. Experimental results above indicated that L78 is involved in the Ca² transport across the endoplasmic reticulum membrane, and moreover, appropriate turns at GPG862-864 and near A893 are essential for D351 phosphorylation at the cytoplasmic domain P. Thereby it is suggested that the accurate configuration and flexibility of L78 play important roles for the successive conformational changes accompanying the SERCA1a reaction cycle.

Abstract:Adaptation to sensory inputs in animals influences their awareness and reactions to environment changes. The attenuated activities at all of the levels in sensory pathways, such as sensory receptors, afferent nerves and central nervous system, are likely associated with sensory adaptation. The signal encodings in cortical network neurons and astrocytes for sensory adaptation remain unclear. With the methods of two-photon cellular calcium imaging, electrophysiology and pharmacology in mice, we analyzed the dynamics of the barrel cortical neurons and astrocytes in response to repetitive inputs from whisker tactile. The paired stimuli in identical features to the mouse whiskers induced the activities of neurons and astrocytes in the barrel cortex to be spatially attenuated and temporally asynchronized. The interaction between these neurons and astrocytes became less coordinated. The downregulation in the spatial and temporal activities of the neurons and astrocytes was significantly reversed by locally using an inhibitor of glutamatergic AMPA-receptor(AMPAR) desensitization. Therefore, the inactivity and asynchrony of network neurons and astrocytes in barrel cortex through AMPAR desensitization are associated with encoding the adaptation of whisker tactile sensation.