ABSTRACT
Autophagy has been shown to facilitate replication or production of avian reovirus (ARV); nevertheless, how ARV induces autophagy remains largely unknown. Here, we demonstrate that the nonstructural protein p17 of ARV functions as an activator of autophagy. ARV-infected or p17-transfected cells present a fast and strong induction of autophagy, resulting in an increased level of autophagic proteins Beclin 1 and LC3-II. Although autophagy was suppressed by 3-methyladenine or shRNAs targeting autophagic proteins (Beclin 1, ATG7, and LC3) as well as by overexpression of Bcl-2, viral transcription, σC protein synthesis, and virus yield were all significantly reduced, suggesting a key role of autophagosomes in supporting ARV replication. Furthermore, we revealed for the first time that p17 positively regulates phosphatase and tensin deleted on chromosome 10 (PTEN), AMP-activated protein kinase (AMPK), and dsRNA dependent protein kinase RNA (PKR)/eIF2α signaling pathways, accompanied by down-regulation of Akt and mammalian target of rapamycin complex 1, thereby triggering autophagy. By using p53, PTEN, PKR, AMPK, and p17 short hairpin RNA (shRNA), activation of signaling pathways and LC3-II levels was significantly suppressed, suggesting that p17 triggers autophagy through activation of p53/PTEN, AMPK, and PKR signaling pathways. Furthermore, colocalization of LC3 with viral proteins (p17 and σC), p62 with LAMP2 and LC3 with Rab7 was observed under a fluorescence microscope. The expression level of p62 was increased at 18 h postinfection and then slightly decreased 24 h postinfection compared with mock infection and thapsigargin treatment. Furthermore, disruption of autophagosome-lysosome fusion by shRNAs targeting LAMP2 or Rab7a resulted in inhibition of viral protein synthesis and virus yield, suggesting that formation of autolysosome benefits virus replication. Taken together, our results suggest that ARV induces formation of autolysosome but does not induce complete autophagic flux.
Subject(s)
AMP-Activated Protein Kinases/metabolism , Autophagy , Orthoreovirus, Avian/metabolism , PTEN Phosphohydrolase/metabolism , Signal Transduction , Viral Nonstructural Proteins/metabolism , Virus Replication/physiology , AMP-Activated Protein Kinases/genetics , Animals , Apoptosis Regulatory Proteins/metabolism , Capsid Proteins/genetics , Capsid Proteins/metabolism , Cell Line , Chickens , Enzyme Activation , Eukaryotic Initiation Factor-2/metabolism , Gene Expression Regulation , Gene Knockdown Techniques , Humans , Mice , Microtubule-Associated Proteins/metabolism , Models, Biological , Orthoreovirus, Avian/growth & development , Orthoreovirus, Avian/physiology , PTEN Phosphohydrolase/genetics , Phagosomes/metabolism , RNA, Double-Stranded/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction/genetics , Tumor Suppressor Protein p53/metabolism , eIF-2 Kinase/metabolism , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
INTRODUCTION: This study explores the motivations of overseas liver transplant recipient (OLTR) families of Taiwanese OLTR who undergo the procedure in mainland China. We report the waiting time to receive the transplant in mainland China as well as the rational and service. PATIENTS AND METHODS: This exploratory qualitative method reflects guided face-to-face, semistructured interviews with families members of OLTRs. Data were subjected to content analysis. RESULTS: We interviewed 19 OLTR family members (15 females and 4 males who were between 29 and 71 years of age; mean 55.1 years) regarding 19 patients who had (17 males and 2 females who were between 36 and 71 years of age, mean, 54.6 years). The OLTR underwent transplantation in three cities in mainland China: Tianjin, Shanghai, and Guangzhou. After arrival the average waiting time was 33.1 days. Subjects reported the following reasons to help patients undergo the procedure in mainland China: (1) it is difficult to have the procedure in Taiwan; (2) the desire to extend life; and ((3)) there is no domestic living donor. Seven reasons for serving as OLTR supportive family members were identified: (1) The role and obligation in the marital relationship; (2) a close bloodline relationship; (3) insufficient manpower; (4) an individual's availability; (5) evasion of responsibility by other family members; (6) compensation for inadequate caring efforts earlier in life; and (7) an unwillingness to disturb other relatives' lives. Finally, the following support for the OLTR was reported: providing company during medical treatment/doctor visits, food preparation, massage, daily assistance, medical care, and psychological support. CONCLUSIONS: Taiwanese OLTR family members' perspectives throughout the transplant process may provide better understanding of living experiences and concerns during the stages of overseas liver transplantation.
Subject(s)
Caregivers/psychology , Family/psychology , Liver Transplantation , Travel , Adult , Aged , China , Female , Humans , Male , Middle Aged , TaiwanABSTRACT
Similar to blood types, human plasma haptoglobin (Hp) is classified into three phenotypes: Hp 1-1, 2-1 and 2-2. They are genetically inherited from two alleles Hp 1 and Hp 2 (represented in bold), but only the Hp 1-1 phenotype is found in almost all animal species. The Hp 2-2 protein consists of complicated large polymers cross-linked by alpha2-beta subunits or (alpha2-beta)n (where n>or=3, up to 12 or more), and is associated with the risk of the development of diabetic, cardiovascular and inflammatory diseases. In the present study, we found that deer plasma Hp mimics human Hp 2, containing a tandem repeat over the alpha-chain based on our cloned cDNA sequence. Interestingly, the isolated deer Hp is homogeneous and tetrameric, i.e. (alpha-beta)4, although the locations of -SH groups (responsible for the formation of polymers) are exactly identical to that of human. Denaturation of deer Hp using 6 m urea under reducing conditions (143 mmbeta-mercaptoethanol), followed by renaturation, sustained the formation of (alpha-beta)4, suggesting that the Hp tetramers are not randomly assembled. Interestingly, an alpha-chain monoclonal antibody (W1), known to recognize both human and deer alpha-chains, only binds to intact human Hp polymers, but not to deer Hp tetramers. This implies that the epitope of the deer alpha-chain is no longer exposed on the surface when Hp tetramers are formed. We propose that steric hindrance plays a major role in determining the polymeric formation in human and deer polymers. Phylogenetic and immunochemical analyses revealed that the Hp 2 allele of deer might have arisen at least 25 million years ago. A mechanism involved in forming Hp tetramers is proposed and discussed, and the possibility is raised that the evolved tetrameric structure of deer Hp might confer a physiological advantage.