A growing body of evidence has indicated the important role of autophagy receptors in directing ubiquitinated or non-ubiquitinated cargos towards autophagy. Autophagy receptors bind to LC3 (microtubule-associated protein 1 light chain 3) on phagophore and autophagosome membranes, and recognize signals on cargoes in the delivery system of autophagy. However, the diverse domains in the receptor structures determine that their roles would never be limited to autophagy. Up to date, increasing numbers of the receptor proteins have been demonstrated to serve as a molecular link or switch participating in autophagic degradation, apoptosis or cell survival signals. Here, we highlight the non-autophagic roles of these receptor proteins to draw attention to this growing research topic.
Apoptosis ; Autophagy ; Humans ; Microtubule-Associated Proteins ; physiology ; Signal Transduction ; Ubiquitination

Multifunctional sperm protein 22 (SP22) is expressed ubiquitously and related to quite a few diseases. Located on the sperm surface, SP22 has an enzymatic activity that may assist sperm in penetrating into the ovum. SP22 may be carcinogenic in conspiracy with the factor ras. Among all species SP22 is highly conservative, which demonstrates its importance to life. More and more studies indicate that SP22 is directly correlated with male infertility and Parkinsons disease. This article summarizes recent researches on SP22 in the gene structure, protein structure and functional characteristics.
Animals ; Gene Components ; Humans ; Male ; Microtubule-Associated Proteins ; chemistry ; genetics ; physiology ; Protein Conformation ; Protein Deglycase DJ-1 ; Rats ; Spermatozoa ; physiology

BACKGROUNDNeuroblastoma, one of the common tumors in children, possesses the feature of natural regression that might be related to apoptosis caspase-3 and survivin are believed to respectively induce and inhibit apoptosis. We investigated the expression of caspase-3 and survivin in pediatric neuroblastoma and the role that these genes played in apoptosis.

METHODSThe expression of caspase-3 and survivin in pediatric neuroblastoma tissue samples was detected using in situ hybridization, ter mintuesal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), and immunohistochemical staining. The role that these genes played in apoptosis was then evaluated.

RESULTSA converse correlation was observed between the expression of survivin and caspase-3. When survivin was expressed at high levels in neuroblastoma samples, caspase-3 expression was downregulated, and the apoptotic index decreased simultaneously.

CONCLUSIONThere is a converse correlation between the expression of caspase-3 and the expression of survivin in neuroblastoma cells, indicating that caspase-3 might induce apoptosis, and survivin may inhibit this process.

Apoptosis ; Caspase 3 ; Caspases ; analysis ; physiology ; Female ; Humans ; Immunohistochemistry ; Infant ; Infant, Newborn ; Inhibitor of Apoptosis Proteins ; Male ; Microtubule-Associated Proteins ; analysis ; physiology ; Neoplasm Proteins ; Neuroblastoma ; chemistry ; pathology

OBJECTIVE: To investigate whether autophagy mediates the effects of aldehyde dehydrogenase 2 (ALDH2) on the proliferation of neonatal rat cardiac fibroblasts cultured in high glucose. METHODS: Cardiac fibroblasts were isolated from neonatal (within 3 days) SD rats and subcultured. The fibroblasts of the third passage, after identification with immunofluorescence staining for vimentin, were treated with 5.5 mmol/L glucose (control group), 30 mmol/L glucose (high glucose group), or 30 mmol/L glucose in the presence of Alda-1 (an ALDH2 agonist), daidzin (an ALDH2 2 inhibitor), or both. Western blotting was employed to detect ALDH2, microtubule-associated protein 1 light chain 3B subunit (LC3B) and Beclin-1 in the cells, and a hydroxyproline detection kit was used for determining hydroxyproline content in cell culture medium; CCK- 8 kit was used for assessing the proliferation ability of the cardiac fibroblasts after the treatments. RESULTS: Compared with the control cells, the cells exposed to high glucose exhibited obviously decreased expressions of ALDH2, Beclin-1 and LC3B and increased cell number and hydroxyproline content in the culture medium. Treatment of the high glucose-exposed cells with Alda-1 significantly increased Beclin-1, LC3B, and ALDH2 protein expressions and lowered the cell number and intracellular hydroxyproline content, whereas the application of daidzin resulted in reverse changes in the expressions of ALDH2, Beclin-1 and LC3B, viable cell number and intracellular hydroxyproline content in high glucose-exposed cells. CONCLUSIONS Mitochondrial ALDH2 inhibits the proliferation of neonatal rat cardiac fibroblasts induced by high glucose, and the effect is possibly mediated by the up-regulation of autophagy-related proteins Beclin-1 and LC3B.
Aldehyde Dehydrogenase ; Aldehyde Dehydrogenase, Mitochondrial ; metabolism ; Animals ; Animals, Newborn ; Autophagy ; Beclin-1 ; physiology ; Fibroblasts ; Glucose ; Microtubule-Associated Proteins ; Mitochondrial Proteins ; Rats ; Rats, Sprague-Dawley

BACKGROUNDAutophagy has been found to be involved in animal and cell models of atherosclerosis, but to date, it lacks general observation in human atherosclerotic plaques. Here, we investigated autophagy in smooth muscle cells (SMCs), endothelial cells (ECs), and macrophages in human atherosclerotic plaques via transmission electron microscopy (TEM), western blotting, and immunohistochemistry analysis.

METHODSThe histopathologic morphology of these plaques was observed via hematoxylin and eosin staining. The ultrastructural morphology of the SMCs, ECs, and macrophages in these plaques was observed via TEM. The localization of microtubule-associated protein 1 light chain 3 (MAP1-LC3), a relatively special maker of autophagy, in plaques was observed by double fluorescent immunochemistry and western blotting.

RESULTSAll of these human atherosclerotic plaques were considered advanced and unstable in histologically observation. By double fluorescent immunochemistry, the expression of LC3-II increased in the SMCs of the fibrous cap, the macrophages, and the microvascular ECs of the plaque shoulders. The protein level of LC3-II by western blotting significantly increased in plaques compared with normal controls. In addition, TEM observation of plaques revealed certain features of autophagy in SMCs, ECs, and macrophages including the formation of myelin figures, vacuolization, and the accumulation of inclusions in the cytosol. These results indicate that autophagy is activated in SMCs, ECs, and macrophages in human advanced atherosclerotic plaques.

CONCLUSIONSOur study is to demonstrate the existence of autophagy in human atherosclerotic plaques by different methods, which may contribute to the development of pharmacological approaches to stabilize vulnerable and rupture-prone lesions.

Atherosclerosis ; metabolism ; physiopathology ; Autophagy ; physiology ; Endothelial Cells ; pathology ; Humans ; In Vitro Techniques ; Microscopy, Electron, Transmission ; Microtubule-Associated Proteins ; metabolism ; Myocytes, Smooth Muscle ; pathology ; Plaque, Atherosclerotic ; metabolism ; physiopathology ; ultrastructure

MicroRNAs (miRNAs) are endogenously expressed small, non-coding transcripts that regulate protein expression. Substantial evidences suggest that miRNAs are enriched in central nervous system, where they are hypothesized to play pivotal roles during neural development. In the present study, we analyzed miRNAs expression in mice cerebral cortex and hippocampus at different developmental stages and found miR-29a increased dramatically at postnatal stages. In addition, we provided strong evidences that miR-29a is enriched in mature neurons both in vitro and in vivo. Further investigation demonstrated that the activation of glutamate receptors induced endogenous miR-29a level in primary neurons. Moreover, we showed that miR-29a directly regulated its target protein Doublecortin (DCX) expression, which further modulated axon branching in primary culture. Together, our results suggested that miR-29a play an important role in neuronal development of mice cerebrum.
Animals ; Axons ; metabolism ; physiology ; Hippocampus ; growth & development ; metabolism ; Mice ; MicroRNAs ; genetics ; metabolism ; Microtubule-Associated Proteins ; genetics ; Neurogenesis ; Neurons ; metabolism ; Neuropeptides ; genetics ; Primary Cell Culture

AIMTo characterize the coexpression of survivin, an inhibitor of apoptosis (IAF), and human telomerase reverse transcriptase (hTERT) in human testes with varying spermatogenic function.

METHODSTranscript levels of survivin mRNA and hTERT mRNA were determined in normal testes (n=11) and testes with defective spermatogenesis (n=28) using real-time reverse-transcription polymerase chain reaction (RT-PCR). The histological work-up was performed according to a modified Johnsen score.

RESULTSExpressions of both survivin and hTERT were highest at median levels of 96.8 and 709 in normal spermatogenesis and dropped to 53.3 and 534 in testes with postmeiotic spermatogenic arrest (n=10). In severe spermatogenic failure (n=18), survivin expression was lacking in most specimens (n=16), whereas at least low levels of testicular hTERT expression were largely detectable with a normalized expression of 73 in premeiotic spermatogenic arrest (n=7) and 45 in patients with Sertoli cell-only syndrome (SCOS) (n=3). Both survivin and hTERT expressions increased with a progressing Johnsen score (P for trend=0.001).

CONCLUSIONAlthough both survivin and hTERT are correlated with spermatogenic function, they show different expression patterns in testes of infertile patients. These findings substantiate results from studies in the rodent testis suggesting a predominant expression of survivin in meiotically dividing germ cells.

Biopsy ; DNA-Binding Proteins ; biosynthesis ; Gene Expression ; physiology ; Humans ; Infertility, Male ; metabolism ; Inhibitor of Apoptosis Proteins ; Male ; Microtubule-Associated Proteins ; biosynthesis ; Neoplasm Proteins ; biosynthesis ; Spermatogenesis ; physiology ; Telomerase ; biosynthesis ; Testis ; metabolism

OBJECTIVETo study the protective effect of bone marrow stromal cells (BMSCs) upon childhood leukemia cells and the influence of VLA-4 antibody in vitro on leukemia cell apoptosis.

METHODSBMSCs from children with acute leukemia-were isolated by human lymphocyte separation medium. BMSCs (adherent) and leukemia cells (suspended) were cultured in vitro. This study included four groups: leukemia cells alone (control), leukemia cells+BMSCs, leukemia cells+BMSCs supernatant and leukemia cells+BMSCs+VLA-4 antibody. The apoptosis rate of leukemia cells in the four groups was determined by Annexin Ⅴ-FITC double-labeled flow cytometry. The expression of survivin and bcl-2 genes in leukemia cells was ascertained by RT-PCR.

RESULTSThe apoptosis rate of leukemia cells in the leukemia cells+BMSCs and the leukemia cells+BMSCs supernatant groups was lower than that in the control group (P<0.05). Compared with the leukemia cells+BMSCs and the leukemia cells+BMSCs supernatant groups, the apoptosis rate of leukemia cells in the VLA-4 antibody group increased significantly (P<0.05). In the VLA-4 antibody group, the apoptosis rate of leukemia cells increased with prolonged culture time. There were significant differences in the apoptosis rate between 12 hrs and 24 hrs after VLA-4 antibody treatment (P<0.01). The expression of survivin and bcl-2 genes in leukemia cells from the VLA-4 antibody groups was reduced compared with that from the leukemia cells+BMSCs and the leukemia cells+BMSCs supernatant groups (P<0.05).

CONCLUSIONSBMSCs play protective roles on leukemia cells. VLA-4 antibody can block the adhesion between BMSCs and leukemia cells and promote leukemia cell apoptosis.

Adolescent ; Antibodies ; therapeutic use ; Apoptosis ; Bone Marrow Cells ; physiology ; Child ; Child, Preschool ; Female ; Genes, bcl-2 ; Humans ; Infant ; Inhibitor of Apoptosis Proteins ; Integrin alpha4beta1 ; immunology ; Leukemia ; pathology ; therapy ; Male ; Microtubule-Associated Proteins ; genetics ; Stromal Cells ; physiology

1-Alkyl-2-acetylglycerophosphocholine Esterase ; genetics ; Chromosome Aberrations ; Humans ; Infant ; Infant, Newborn ; Ion Channels ; physiology ; Melanocyte-Stimulating Hormones ; genetics ; Microtubule-Associated Proteins ; genetics ; Mutation ; Neurons ; physiology ; Neuropeptides ; genetics ; Spasms, Infantile ; etiology ; genetics ; Tumor Suppressor Proteins ; genetics

Adolescent ; Adult ; Aged ; Cadherins ; genetics ; metabolism ; physiology ; Female ; Humans ; Inhibitor of Apoptosis Proteins ; Ki-67 Antigen ; genetics ; metabolism ; Male ; Microtubule-Associated Proteins ; genetics ; metabolism ; physiology ; Middle Aged ; Neoplasm Invasiveness ; physiopathology ; Pituitary Neoplasms ; pathology ; physiopathology ; Young Adult