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Biomedical subjects

Hong Chen

Publications and source records attributed to Hong Chen.

At least 181 records · Page 10Linked to original sources

Clinical applications of real-time PCR for diagnosis and treatment of human cytomegalovirus infection in children.

There are many methods of detecting human cytomegalovirus (HCMV) infection. So far, the quantitative polymerase chain reaction (PCR) has been very useful not only in aiding in the diagnosis of HCMV but also in determining the severity and predicting HCMV infection. However, it is time-consuming and labor intensive. Real-time PCR (RT-PCR) is an exception, for it allows rapid quantification of HCMV DNA load. Our group used this method for detecting and monitoring HCMV and compared it with the diagnostic criterion recommended by the Pediatric Branch of Chinese Medical Association, in 45 children suspected of having HCMV infection. The response to two types of antiviral treatment on HCMV DNA load was also monitored in HCMV hepatitis cases. RT-PCR was positive in 30 cases while the diagnostic criterion, which includes enzyme-linked immunosorbent assay (ELISA) and/or conventional PCR, was positive in 32 cases. The decrease in the HCMV DNA load was achieved earlier in the modified treatment group compared with the conventional treatment group. A 10(3) copies/ml of HCMV DNA load of is a useful cut-off value in predicting patients who will have symptoms of the disease. RT-PCR can be used not only in detecting HCMV but also in monitoring response to antiviral treatment and risk of having symptoms of the disease.

Case-Control Studies↗

Plasma evaluation for ivermectin in llamas (Lama glama) after standard subcutaneous dosing.

Plasma levels of the parasiticide ivermectin were studied by high-performance liquid chromatography in five llamas (Lama glama) after single 200 microg/kg s.c. injections. Ivermectin levels were undetectable in plasma samples drawn up to 4 wk after injection, suggesting that the dosage used was insufficient to reach therapeutic concentrations in this species.

Animals↗

Colorimetric detection of polynucleotides on polypropylene slices.

The gold-label-silver-stain method (GLSS) for DNA hybridization detection has been receiving increased interest as a colorimetric detective method, demonstrating the advantages of non-radioactivity, non-quenching effect of fluorescence and simplicity for analytical equipment. A colorimetric detection based on the GLSS method was applied to DNA arrays in situ synthesized on polypropylene (PP) slices. In this paper a simple plasma treatment was employed to graft amino (-NH2) on the polypropylene slice surfaces, where DNA probes were immobilized via in situ synthesis. Hybridization was accomplished by a sandwich hybridization format. With the amplification of Silver Enhancer Solution, the hybridization signals were recorded with a scanner. A target DNA concentration as low as 100 fM was detected. Complementary and mismatched sequences were clearly distinguished, and the ratio of the background-subtracted gray scale values for a perfect match, single-base mismatch, 2-base mismatch and 3-base mismatch is 22:16:9:4. The sensitivity of the in situ synthesis system was 3 orders of magnitude higher than that of the spotting system, and the signals of the former were about 2-times stronger than that of the latter under the same target DNA concentration.

Colorimetry↗

[Evaluation of operation and anesthesia on hemodynamic variables in patients undergoing elective abdominal surgery by noninvasive thoracic bioimpedance technique].

OBJECTIVE: To analyse and discuss the effects of elective abdominal operation and anaesthesia on patients' cardiac output via noninvasive thoracic bioimpedance technique. METHODS: Noninvasive monitoring system HeMo-601 was applied to detect the hemodynamic variables of 32 elective abdominal surgery patients. The clinical data of cardiac output (CO), cardiac index (CI), cardiac working per minute (CW), left ventricular end-diastolic pressure (LVEDP), stroke volume (SV), cardiac stroke working (SW) and heart rate (HR) were analysed at 1 hour before operation, 4-6 hours after operation and 24 hours after operation, respectively. RESULTS: No significant differences were found in CO, CI, CW and LVEDP between various time points and preoperation (all P>0.05). SV and SW at 4-6 hours after operation were significant lower than those before operation (all P<0.05). Whereas, SV and SW at 24 hours after operation were no significant differences compared with those before operation (all P>0.05). As compared with preoperation, HR at 4-6 hours after operation was significantly faster (P<0.05). However, there was no significant difference in HR between 24 hours after operation and preoperation (P>0.05). CONCLUSION: The reductions in SV and SW at 4-6 hours after operation might be a result of anaesthesia that could weaken the contraction of heart. The presence of rapidness of HR at 4-6 hours after operation might be a compensatory mechanism for the decreases in SV and SW. Therefore, optimizing adequate infusion by the greatest extent during and after operation is very crucial for the maintenance of CO, CI and tissue perfusion.

Abdomen↗

[A study on the differences of emotion and depression between patients as doctor/nurse and others occupation with severe acute respiratory syndrome].

OBJECTIVE: To study the emotional and depressive differences between severe acute respiratory syndrome (SARS) patients whose occupations were doctor/nurse and others. METHODS: During the three months when SARS was explosive in 2003, 524 questionnaires were collected from Xuanwu Hospital, You'an Hospital, Xiaotangshan Hospital, Renmin Hospital and Ditan Hospital in Beijing. There were 109 questionnaires finished by patients as doctors/nurses themselves. For a background matching, 109 questionnaires were also finished by the others. RESULTS: From 218 questionnaires, we found that the score on emotional condition (46.6204 +/- 8.4408 vs. 41.6789 +/- 8.612 95, P < 0.001) of SARS patients whose jobs were doctor/nurse was higher than the other groups on while the score of SARS patients whose jobs were doctor/nurse was lower than the other groups (37.7615 +/- 9.026 61 vs. 41.2844 +/- 9.655 25, P = 0.006) regarding depressive condition. The scores of emotional and depressive condition were all correlated with the factor as "I can not master my future". CONCLUSION: Doctors/nurses having SARS had less emotional and depressive conditions than the others, which might due to the difference in medical knowledge, working condition and the route of infection, suggesting that psychological intervention in the post-SARS period called for attention.

Case-Control Studies↗

[Persistent intestinal motility disorder after transient intestinal nematode infection in rats].

OBJECTIVE: To investigate the intestinal motor function (distal colonic manometry and gastrointestinal transit time) after T. spiralis infection in rats. METHODS: Sprague-Dawley rats were infected by administering T. spiralis larvae. Rats were studied on 14, 42, and 56 days post-infection (PI). Age matched non-infected animals served as controls. All rats underwent colonic manometry and gastrointestinal transit time test. RESULTS: (1) The small intestinal inflammation became the most severe on day 14 PI, and returned to normal on day 56. (2) The distal colonic manometry showed significantly active motility in acute infected rats either at rest or upon balloon stimulating. (3) Rat colonic motility parameters were not different from those of the control rats either at rest or upon small volume (1mL) balloon stimulating on day 42 and day 56 PI. But when the balloon was inflated with 2 mL of air, the colonic activity increased significantly compared with that of the control. (4) Gastrointestinal transit time was slower in acute and PI rats than that in the control group. CONCLUSION: Intestinal motility function was abnormal persistently after transient intestinal nematode infection in rats either in distal colonic manometry or in gastrointestinal transit time.

Animals↗

[Study on the prevalence of Tourette syndrome in children and juveniles aged 7-16 years in Wenzhou area].

OBJECTIVE: To study the prevalence and distribution of Tourette syndrome (TS). METHODS: Nine thousand, seven hundred and forty-two children and juveniles aged 7 - 16 years in Wenzhou were studied, using cluster random sampling method. RESULTS: The prevalence of TS among school-age children was estimated to be 0.43% (0.74% for males and 0.07% for females). The prevalence of male children and juveniles was higher than that of female children and juveniles (chi(2) = 25.09, P < 0.001, prevalence ratio = 10.95, prevalence ratio 95% CI: 3.38 - 35.46). The highest prevalence of TS was between 9 - 10 years old. The mean age at onset of TS was 7.7 +/- 2.7 years, with 45.2% of them among 6 - 7 year olds. The rate of delayed diagnosis and rates of misdiagnosis and misclassification of the syndromes were 78.6%, 42.9% and 23.8%, respectively. CONCLUSION: Tourette syndrome had been a common disease of children and juveniles in Wenzhou area. The disease was correlated with age and sex, often misdiagnosed and misclassified. Physicians and as well as general publics should be trained to identify the cases.

Adolescent↗

[Comparative studies on proteins of cytoplasmic male-sterile wheat and its maintainer by 2D-PAGE in Triticum aestivum].

By using 2D-PAGE techniques, protein compositions have been studied at different developmental stage leaf (seedling, tillering, shooting and booting stages) and pollen mother cells (PMC) (meiotic, 1-nucleus and 2-3 nuclei stages) in male sterile wheat and its maintainer. The results indicated that a specific protein (33KD/pI6.3) identified at the shooting and booting stage leaves in male-sterile wheat, but this protein species has not been identified in the male fertile wheat. Four protein species, 53KD/PI5.5, 50KD/PI5.7, 48KD/PI5.6, 20KD/PI7.5 were detected at the 2-3 nuclei stages, which was thought key stage of pollen fertility lost in male-sterile wheat, and these protein species were not be seen in male-fertile wheat. According above experiment results, five protein species which detected in leaf and PMC might participate in fertility regulation and related to the male-sterility of male-sterile wheat.

Electrophoresis, Gel, Two-Dimensional↗

[Study on mitochondrial DNA genetic diversity of some cattle breeds in China].

The complete mitochondrial D-loop sequences, 910 bp in length, in 22 individuals from 8 cattle breeds in China were analyzed. The results showed that A% + T% was about 61.65%. Comparisons of these 22 sequences revealed 66 polymorphic sites, and 5 types of mutation, transition, transversion, insertion, deletion and coexistence site of transition and transversion were observed,with the percentage of 81.82%, 6.06%, 7.57%, 3.03%, 1.52%, respectively. In reference to complete mtDNA D-loop of the European cattle as a control, eight Chinese cattle breeds were classified into 3 groups according to the average percentage of D-loop nucleotide variations. The lowest average percentage of mtDNA D-loop nucleotide variation was in Xizhen cattle, Mongolian cattle, Holstein, Qinchuan cattle with 0.37%, 0.44%, 0.52%, 0.66%, the mediate in Nanyang cattle and Jiaxian cattle with 1.91%, 2.02% and the highest in Jinnan cattle and Yueyang cattle with 4.47%, 4.73%, respectively. The average sequence divergence estimated from D-loop region within breeds and among breeds in China varied from 0.55% - 5.39% and 1.21% - 6.59%, respectively. Comparisons of these 22 sequences revealed 19 mitochondrial haplotypes, the percentage of haplotype was 86.36%, showing that abundant mitochondrial genetic diversity exists in Chinese cattle. The molecular phylogenetic tree of mtDNA D-loop of 8 Chinese cattle breeds was constructed by Neighbor-Joining method. The NJ tree indicated that these mtDNA sequences fell into 3 distinct haplotype groups, it also suggested in molecular level that there were probably 3 maternal origins, of which the main origins of Chinese cattle were from Bos taurus and Bos indicus.

Animals↗

[Clinical study on treating insulin resistance and promoting ovulation in polycystic ovary syndrome].

OBJECTIVE: To investigate the effects of metformin and clomiphene on infertility caused by polycystic ovary syndrome (PCOS) with insulin-resistance (IR) and to observe the effects of metformin on PCOS with pseudoacanthosis nigricans (AN) and IR. METHODS: Seventy infertility patients caused by PCOS with IR were randomly divided into three groups : patients in group Aa (n = 20) took metformin 500 mg only, three times daily for 3 months; patients in group Ab (n = 20) took clomiphene 50 mg only, once daily from the 5th day of menstrual cycle or withdrawal bleeding for 5 days and 3 cycles, and patients in group Ac (n = 30) were treated by metformin and clomiphene for 3 cycles, with the same dosages as groups Aa and Ab. Thirty patients who suffered from PCOS with AN and IR were served as group B, They took metformin only, the same as group Aa. The following indexes were measured before and after three months or cycles of treatment in all the patients: body height, weight, waistline, hipline, body mass index (BMI), waist hip ratio (WHR), fasting insulin (FINS), fasting blood-glucose (FBG), total cholesterol (TC), triglyceride (TG), and sex hormones [follicle-stimulating hormone (FSH), luteotropic hormone (LH), prolactin (PRL), estradiol (E(2)), progestin (P), testosterone (T)]. RESULTS: The pregnant rate was 15% (group Aa), 20% (group Ab), and 57% (group Ac) respectively. It was significantly higher in group Ac than in groups Aa and Ab, (P < 0.01), while there was no significant difference between the latter two groups (P > 0.05). In group Ac the pretreatment levels of FINS, BMI, T, TG, and TC were (49.7 +/- 6.4) mU/L, 29.4 +/- 2.2, (6.4 +/- 2.2) nmol/L, (4.1 +/- 1.0) mmol/L, (6.3 +/- 0.5) mmol/L, and posttreatment levels were (27.7 +/- 1.8) mU/L, 23.6 +/- 5.2, (3.8 +/- 2.0) nmol/L, (2.2 +/- 0.7) mmol/L, (4.6 +/- 0.5) mmol/L. In group Aa pretreatment levels of FINS, BMI, T, TG, and TC were (50.0 +/- 8.2) mU/L, 28.7 +/- 1.2, (6.4 +/- 2.0) nmol/L, (4.3 +/- 1.2) mmol/L, (6.6 +/- 0.3) mmol/L, and posttreatment levels were (29.9 +/- 8.2) mU/L, 22.4 +/- 9.3, (4.3 +/- 0.9) nmol/L, (2.3 +/- 0.3) mmol/L, (4.8 +/- 0.6) mmol/L. In group B pretreatment levels of FINS, BMI, T, TG, and TC were (51.0 +/- 8.1) mU/L, 29.8 +/- 3.1, (6.3 +/- 3.5) nmol/L, (4.5 +/- 1.2) mmol/L, (6.8 +/- 0.2) mmol/L, and posttreatment levels were (28.5 +/- 2.8) mU/L, 23.4 +/- 6.1, (3.0 +/- 0.9) nmol/L, (2.3 +/- 0.9) mmol/L, (5.0 +/- 0.6) mmol/L. In groups Ac, Aa and B, the IR condition was obviously improved and posttreatment serum levels of T, TG, TC, FINS and BMI were significantly lower than those of pretreatment (all P < 0.01). In group Ab pretreatment levels of FINS, BMI, T, TG, and TC were (48.8 +/- 7.4) mU/L, 27.3 +/- 2.8, (6.0 +/- 2.0) nmol/L, (3.9 +/- 1.4) mmol/L, (6.4 +/- 0.6) mmol/L, and posttreatment levels were (42.9 +/- 7.0) mU/L, 27.5 +/- 3.1, (4.0 +/- 2.4) nmol/L, (3.9 +/- 0.3) mmol/L, (5.9 +/- 0.3) mmol/L, (all P > 0.05). Among patients in group B, 90% (27/30) menstrual condition and ovulation function were improved and AN was reduced in different degree after three months' treatment. CONCLUSION: Metformin can increase the sensitivity of PCOS to clomiphene and improve ovulation function of clomiphene. Metformin plus clomiphene is an effective way of treating infertility caused by PCOS with IR.

Adult↗

[Preliminary study on the relationship between chronic sinusitis histomorphology and aerosol].

OBJECTIVE: To observe the relationship between histomorphological changes in mucosa of chronic sinusitis (CS) and aerosol particles. METHODS: The ethmoidal sinus mucus specimens of 60 patients with CS type I, II and III, and 16 cases of normal controls were collected. Meanwhile the pulmonary specimens in autopsy of 5 adult and 5 fetus cases were also collected. The specimens were stained by HE staining and Warthin-Starry (W-S) special aerosol particles staining method respectively, the ethmoidal sinus mucosa basement membrane were displayed by Van Gieson's (VG) special staining method, and its thickness was measured. RESULTS: By the W-S staining, some black aerosol particles were found depositing on the epithelial cells layer of damaged mucosa and in the plasm of the epithelial cells. The degree of deposition was gradually increased in type I, II and III of CS. The number of cases of slight, medium and heavy depositing in type I were 11/20, 7/20, 2/20, in type II 5/20, 9/20, 6/20, and in type III 3/20, 6/20, 11/20 respectively; the more particles deposited, the more thickening the basement membrane. The thickness of the basement membrane in type I, II and III of CS were (12.15 +/- 4.73), (16.67 +/- 2.22), (23.75 +/- 3.48) microm respectively. There were significant differences among type I, II and III (P < 0.01). The black particles in the mucosa epithelium tissues of normal control group and non-damaged mucosa epithelium and desquamation area were seldom seen. On the other hand, the aerosol particles were not seen in the pulmonary specimens of the fetal autopsy. CONCLUSION: In damaged mucosa epithelial cells of the CS, there are aerosol particles existing which may relate with the morphological changes of CS.

Adolescent↗

[Study on the prevalence of tic disorders in schoolchildren aged 7-16 years old in Wenzhou].

OBJECTIVE: To study the epidemiological features of tic disorders (TD) among schoolchildren in Wenzhou area. METHODS: Stratified cluster sampling was carried out to investigate TD in 9742 schoolchildren aged 7 to 16 years old in Wenzhou. RESULTS: The average prevalence rate of TD among school-age children was 104/10 000 (166/10 000 for males, 29/10 000 for females). There was a significantly higher prevalence rate for males than that for females (chi(2) = 43.96, P < 0.001, prevalence ratio = 5.7, prevalence ratio 95% CI: 3.20 - 10.30). The prevalence rates of clinical subtypes in males was significantly higher than that of females while pupils was significantly higher than that in high school students (chi(2) = 11.33, P < 0.01, prevalence ratio = 2.2, prevalence ratio 95% CI: 1.37 - 3.43). Prevalence rate of transient tic disorders (TTD), chronic motor vocal tic disorder (CMVTD), tourette syndrome (TS) were 34/10 000, 27/10 000 and 43/10 000 respectively with the highest among 9-10 years old group. The mean onset age of TD was 8.5 +/- 2.8 years. The peak of onset was among 6-10 year olds. The rate of delayed diagnosis of the disorders was 69.3% and the median in delayed diagnosis was 1.0 year. CONCLUSION: TD is a common disease with high rate of misdiagnoses among schoolchildren in Wenzhou area. Physicians and population should be trained to identify the syndromes and to practice correct diagnosis and effective treatment as early as possible.

Adolescent↗

[Attenuated Salmonella typhimurium as DNA delivery vehicle for DNA-mediated immunization].

OBJECTIVE: To study whether the live attenuated AroA-auxotrophic mutant of Salmonella (S.) typhimurium (SL7207) could be used as DNA delivery vehicle to induce more efficient immune response by using the eukaryotic expression plasmid pCMV-beta as report gene. METHODS: Murine peritoneal macrophages were infected with SL7207(pCMV-beta) in vitro, then the expression of the beta-gal were detected by X-gal staining or RT-PCR. After mice were orally immunized with SL7207(pCMV-beta), the expression of beta-gal in the lymphoid tissue were tested by RT-PCR, humoral responses were tested by ELISA, splenic lymphocyte proliferation were tested by 3H-TdR incorporation and cytotoxic T lymphocyte reaction were tested by JAM test. RESULTS: The results indicated that the plasmid pCMV-beta could be delivered by SL7207 into the nucleus of the murine macrophages efficiently and expressed well in vitro; after mice received oral immunizations with attenuated S.typhimurium SL7207 harboring plasmid pCMV-beta mice, the expression of beta-gal could be detected in the spleen, mesenteric lymph nodes and Peyers patches of the mice. Furthermore, the experiments demonstrated that specific humoral immune responses and cell-mediated immune responses were successfully induced in these immunized mice. Compared with the naked DNA vaccination, SL7207 (pCMV-beta) oral immunization were more efficient in inducing cellular immune responses. CONCLUSIONS: Attenuated Salmonella typhimurium SL7207 could be used as DNA delivery vehicle for oral immunization, which have the ability to deliver the antigen-encoding DNA specifically to APC directly for inducing the specific immune response being dominant with cellular immune response.

Animals↗

Cardiopulmonary bypass in surgery for interrupted aortic arch.

Interrupted aortic arch is a complicated congenital heart defect. Because of its anatomic features, the conventional cardiopulmonary bypass (CPB) procedure is not suitable for the surgery of this type of lesion. Thus, we conducted a retrospective study of CPB in surgery for the disease. Ten patients with interrupted aortic arch underwent surgery by one of three different CPB methods, including profound hypothermia with circulatory arrest in four cases, profound hypothermia with low flow rate in five cases, and normothermia in one case. In profound hypothermic CPB, both ascending aorta and main pulmonary artery were cannulated. Through these two cannulas, the flow was pumped to the upper and lower body separately to cool down the body temperature. After cooling, the main pulmonary artery cannula was removed and interrupted aortic arch was corrected either under low flow rate perfusion or under circulatory arrest. After this, the other intracardiac lesions were repaired under conventional CPB. At the end of CPB, one patient demonstrated third-degree atria-ventricular block and required reinstituting CPB and a second procedure to repair the ventricular septal defect (VSD). In the intensive care unit, one patient developed lung infection and dyspnea after extubation that required intubation and mechanical ventilation for another several days. Another patient required 3 days of peritoneal dialysis caused by low cardiac output, hyperkalemia, and oliguria. All patients survived. The mechanical ventilation times were from 8 hours to 8 days and stays in the intensive care unit were from 4 to 12 days. Profound hypothermic cardiopulmonary bypass either with low flow rate or with circulatory arrest is equally the preferable choice for the surgery of interrupted aortic arch.

Aorta↗

[The ht-PAm cDNA knock-in the goat beta-casein gene locus].

The production of recombinant protein is one of the major successes of biotechnology, animal cells are required to synthesize proteins with the appropriate post-translational modifications. Transgenic animal mammary gland bioreactor are being used for this purpose. Gene targeting is a more powerful method to produce mammary gland bioreactor, and nuclear transfer from cultured somatic cells provides an wonderful means of cell-mediated transgensis. Here we describe efficient and reproducible gene targeting in goat fetal fibroblasts to place the human tissue plasminogen activator mutant (ht-PAm) cDNA at the beta-casein locus, and would produce the transgenic goat by nuclear transfer. To construct the gene targeting vector pGBC4tPA, the milk goat beta-casein genomic DNA sequence for homologous arms had been cloned firstly. The left arm was 6.3 kb fragment including goat beta-casein gene 5' flanking sequence, and the right arm was 2.4 kb fragement including beta-casein gene from exon 8 to exon 9. The ht-PAm cDNA was subcloned in the goat beta-casein gene exon 2, and the endogenous start condon was replaced by that of ht-PAm. The bacterial neomycin (neo) gene as positive selection marker gene, was placed in the beta-casein gene intron 7, the thymidine kinase (tk) as the negative selection marker gene, was just outside the right arm. The validity of the positive-negative selection vector (PNS), was tested, and targeting homologous recombination (HR) were elevated to 5-fold with the negative selection marker using the drug GANC. The DNA fragment in which two LoxP sequence was delected effectively using Cre recombinase in vitro. Goat fetal fibroblasts were thawed and cultured to subconfluence before transfection, about 10(7) fibroblasts were electoporated at 240V, 600 microF in 0.8 mL PBS buffer containing linear pGBC4tPA. transfected cells were cultured in collagen-coated 96-wellplate for 24h without selection, then added the drug G418 (600 microg/mL) and GANC (2 micromol/L). After 12 days of selection, well separated G418r/GANCr clones were isolated and expanded in 24-wellplate. 244 clones were selected, and only 90 clones could grow and be tested by PCR screening for targeting. The primary result demonstrated that 31 targeting cell clones with homologous recombination events were obtained, and 2 cell clones was verified by DNA sequence analysis on the homologous recombination region.

Animals↗

Epigenetic regulation of coxsackie and adenovirus receptor (CAR) gene promoter in urogenital cancer cells.

Coxsackie and adenovirus receptor (CAR) is not only a high-affinity receptor for adenovirus, but also a tumor inhibitor in both prostate and bladder cancer lines. Decreased CAR gene expression is often detected in cancer specimens; however, the mechanism(s) is still unknown. In this study, we cloned the entire CAR gene and characterized the core promoter sequence of the CAR gene. The CAR gene promoter activity correlated with the differential expression of CAR mRNA levels from several urogenital cancer cell lines, indicating that the down-regulation of CAR gene expression is mediated by transcriptional regulation. It is known that epigenetic control, such as DNA methylation and histone acetylation of chromatin structure, dictates gene expression. Data from this study indicate that the activation of the CAR gene promoter is modulated by histone acetylation, but not by DNA methylation, in urogenital cancer cells. Also, a potent cancer chemotherapeutic agent (FR901228), a histone deacetylase inhibitor, was able to induce endogenous CAR gene expression in several urogenital cancer cells. Taken together, epigenetic control of CAR gene underlies the down-regulation of this gene in urogenital cancers.

Base Sequence↗

Rapid Ca2+-dependent decrease of protein ubiquitination at synapses.

Protein ubiquitination has been implicated in the regulation of axonal growth and synaptic plasticity as well as in the pathogenesis of neurodegenerative diseases. Here we show that depolarization-dependent Ca2+ influx into synaptosomes produces a global, rapid (range of seconds), and reversible decrease of the ubiquitinated state of proteins, which correlates with the Ca2+-dependent dephosphorylation of several synaptic proteins. A similar general decrease in protein ubiquitination was observed in nonneuronal cells on Ca2+ entry induced by ionomycin. Both in synaptosomes and in nonneuronal cells, this decrease was blocked by FK506 (a calcineurin antagonist). Proteins whose ubiquitinated state was decreased include epsin 1, a substrate for the deubiquitinating enzyme fat facets/FAM, which we show here to be concentrated at synapses. These results reveal a fast regulated turnover of protein ubiquitination. In nerve terminals, protein ubiquitination may play a role both in the regulation of synaptic function, including vesicle traffic, and in the coordination of protein turnover with synaptic use.

Animals↗