[Mechanism of action of Jieduhuayu granules for remission of oxidative stress in hepatocytes]

Objective: To study and explore the effect and mechanism of action of Jieduhuayu granules on oxidative injury of human liver L02 cells. Methods: Human liver L02 oxidative injury model was established with 0.1 mmol/ L H(2)O(2) intervention for 1 h, and treated with different concentrations of Jieduhuayu (JDHY) solution. Hepatocytes were divided into five groups: normal, H(2)O(2), H(2)O(2) + JDHY (0.5 mg/ml), H(2)O(2) + JDHY (1 mg/ml), and H(2)O(2) + JDHY (1.5 mg/ml). MTT assay was used to detect hepatocytes activity. Transmission electron microscope was used to observe mitochondrial morphology in hepatocytes. Biochemical test was used to detect the levels of superoxide dismutase, lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, malondialdehyde, and reduced glutathione and albumin in hepatocytes. Western blot was used to detect the expression levels of rabbit anti-phosphatidylinositol 3-kinase (PI3K), AKT and mTOR in hepatocytes. One-way analysis of variance was used for comparison between multiple groups, and the LSD method was used for pairwise comparison. Results: Compared with the normal group, the cell proliferation activity (P < 0.05), mitochondrial vacuolization, superoxide dismutase activity, reduced albumin and glutathione content, and PI3K, AKT, and mTOR protein expression levels in the H(2)O(2) group were all significantly reduced (P < 0.05), while the content of malondialdehyde and the activities of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase were significantly increased (P < 0.05). Compared with H(2)O(2) group, the cell proliferation activity (P < 0.05), alterations in morphological remission of mitochondria, superoxide dismutase activity, reduced albumin and glutathione content, and PI3K, AKT and mTOR protein expression levels in the H(2)O(2) + JDHY (1 mg/ml) and H(2)O(2) + JDHY (1.5 mg/ml) group (P < 0.05) were all significantly increased (P < 0.05), while malondialdehyde content and alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities were significantly decreased (P < 0.05). Conclusion: Jieduhuayu granule can effectively improve oxidative stress and mitochondrial injury in hepatocytes, and its effect may be related to the promoting expression of PI3K/AKT/mTOR signaling pathways.

O-145 Green Tea catechins EGCG and pro-drug of EGCG (Pro-EGCG) inhibit endometriosis through targeting molecules regulating macrophages and B cells

Study question

What are the therapeutic targets and mechanisms of green tea EGCG and Pro-EGCG in treating endometriosis?

Summary answer

EGCG and Pro-EGCG have unique molecular targets to regulate interactions of B cells, macrophages and endometriotic cells and limit the growth and development of endometriosis.

What is known already

Current treatments of endometriosis are mainly hormonal suppression and surgical ablation or removal. Our previous studies showed EGCG significantly inhibits development of experimental endometriosis in mice. Pro-EGCG is more effective than EGCG in term of anti-endometriosis, anti-angiogenesis and anti-oxidation (Wang, et. al., 2013; Xu, et al., 2011). Dysfunctional immunological activities of macrophages and B cells were found in women with endometriosis. The molecular targets, underlying mechanism and differential therapeutic efficacy of EGCG and Pro-EGCG, as well as their anti-inflammatory activities are still not known.

Study design, size, duration

Multiplexed Proteome Integral Stability Alteration (PISA) assay (Gaetani et al.,2019), followed by MS/MS was applied to identify the molecular targets of EGCG and Pro-EGCG in endometriotic cells. Pharmacological studies of EGCG and Pro-EGCG on endometriotic cell line and endometriosis models in mice were performed to characterise their anti-endometriosis and anti-inflammatory effects. Gene silencing and over-expression experiments were conducted to confirm the immunoregulatory mechanisms.

Participants/materials, setting, methods

Endometriotic (Hs832(C)T) cell lines in culture and lysate were treated for chemical proteomics analysis. SiRNA and overexpression vectors were transfected to the cells in vitro and lesions in vivo. Hs832(C).T, monocytic cells (THP-1) and control B cell (Raji null) lines were used for co-culture assays to study the interaction between endometriotic and immune cells in vitro. Endometriosis mice model was established for immunostaining and microarray analysis of lesions to characterise the molecular pathways in vivo.

Main results and the role of chance

MTDH and PXK were the strongest and most differential targets of EGCG and Pro-EGCG in both cells lysate and cell culture of Hs832(C).T, respectively. Gene silencing and overexpression of the protein targets in vitro and in vivo significantly altered expressions of downstream proteins, including BLK and EGF after PXK, and MYC and AKT after MTDH, as well as endometriosis-related genes such as VEGFC and MMP9. Co-culture assays of Hs832(C).T with Raji null or THP-1 induced macrophages showed that expressions of PXK, MTDH, downstream targets, and immune-related genes were significantly increased after incubation of recombinant proteins, but were significantly decreased after EGCG and Pro-EGCG treatment. M1 and M2 macrophages, as well as B cells were significantly reduced after the treatments in vitro and in vivo. Double immunofluorescent staining of lesions showed that CD68, CD163 or CD20 co-expressed with MTDH, PXK and downstream targets, and numbers of the co-expressed cells were significantly reduced after treatments in vivo. Microarray experiment further identified the upstream and downstream genes of MTDH or PXK contributing to the growth and development of endometriosis.

Limitations, reasons for caution

Results of this pharmacological and mechanistic study require clinical samples to validate the anti-endometriosis effects of EGCG and Pro-EGCG. Effects of other potential pharmaceuticals targeting the macrophages and B cells on endometriosis are needed.

Wider implications of the findings

The findings provide pharmacological and mechanistic data for future development of EGCG and Pro-EGCG as new treatment for endometriosis. This study shows that macrophage and B cell could be potential therapeutic targets for treatment of endometriosis, which opens up new horizon for the novel immunotherapy for endometriosis.

Trial registration number

NA

[Analysis of imatinib trough concentration at steady state in adjuvant therapy of patients with high risk gastrointestinal stromal tumor]

Objective: To explore the features of imatinib mesylate (IM) plasma concentration during adjuvant therapy and clinical factors associated with IM plasma concentration in patients with high risk gastrointestinal stromal tumors (GIST), and to determine whether IM plasma concentration <1100 μg/L influences the efficacy of adjuvant therapy. Methods: A retrospective case control study method was used. Case inclusion criteria: (1) complete resection of lesion and GIST confirmed by pathology; (2) high risk classified according to modified National Institutes of Health classification system (2008); (3) administration of IM 400 mg/d for at least 1 month; (4) not taking the medication likely affecting IM pharmacokinetic, such as rifampicin, dilantin, and carbamazepine, within 1 month before blood collection. Data of GIST patients who visited GIST Disease - Oriented Outpatient, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology between January 2015 to December 2018 were retrospectively analyzed. After taking IM for 22-26 hours, 5 ml of peripheral venous blood was collected into EDTA anticoagulant tube. IM plasma concentration was detected by using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Patients were divided into <1100 μg/L group and ≥1100 μg/L group according to plasma concentration. Linear regression was used to analyze the relevance between clinical features and IM plasma concentration. Parameters with normal distribution were analyzed by Pearson correlation coefficient, and parameters with non-normal distribution were analyzed by Spearman correlation. Kaplan-Meier survival curves and COX regression model were used for survival analysis. Results: Among the 85 patients enrolled in the study, 49 patients (57.6%) were male and 36 (42.4%) were female, with mean age of (51.9±11.0) years. The body mass index was (22.5±2.9) kg/m(2) and body surface area was (1.6±0.2) m(2). Thirty patients received gene test, including 23 patients with c-Kit exon 11 mutation, 4 with c-Kit exon 9 mutation, 1 with c-Kit exon 11 and 17 mutation and 2 without c-Kit or PDGFRA gene mutation. The mean IM plasma concentration was (1391.4±631.3) μg/L, and there were 32 patients with plasma concentration <1100 μg/L and 53 patients with plasma concentration ≥1100 μg/L. There were no statistically significant differences between the two groups in gender, age, body mass index, body surface area, hematological examination (white blood cells, albumin, alanine aminotransferase, aspartate aminotransferase and serum creatinine), tumor location, tumor size, mitotic counts, duration of adjuvant therapy and methods of operation (all P>0.05). Positive correlation between IM plasma concentration and serum creatinine was observed in linear regression analysis (r=0.297, P=0.007), but there were no correlations between IM plasma concentration and age (r=0.044, P=0.686), body mass index (r=0.066, P=0.547), body surface area (r=-0.010, P=0.924), white blood cells (r=-0.080, P=0.478), albumin (r=-0.065, P=0.563), alanine aminotransferase (r=0.114, P=0.308), aspartate aminotransferase (r=0.170, P=0.127) and duration of adjuvant therapy (ρ=0.060, P=0.586). There was no statistically significant difference in IM plasma concentration between patients with different genders (t=0.336, P=0.738) and patients with different surgical methods (F=0.888, P=0.451). Up to March 1, 2019. the median follow-up time was 30 (range 4-49) months. Tumor recurrence was detected in two patients with plasma concentration <1100 μg/L and two with plasma concentration ≥1100 μg/L. One recurrent patient with plasma concentration <1100 μg/L was detected to harbor c-Kit exon 11 and exon 17 mutations, and the other did not receive gene detection. Two recurrent patients with plasma concentration ≥1100 μg/L were both detected to harbor c-Kit exon 9 mutation. The 3-year relapse-free survival rate was 96.4% in the cohort, 96.2% in patients with plasma concentration <1100 μg/L, and 96.6% in patients with plasma concentration ≥1100 μg/L. No significant difference in relapse-free survival was observed between the two groups (P=0.204). Univariate Cox analysis showed that IM plasma concentration <1100 μg/L was not a risk factor for patients with high risk GIST (HR=0.238, 95% CI: 0.022-2.637, P=0.242). Conclusions: IM plasma concentration of adjuvant therapy in patients with high risk GIST varies with individual. Patients with higher level of serum creatinine are more likely to have a higher plasma concentration. A blood drug concentration standard of less than 1100 μg/L for advanced GIST patients may not influence the prognosis of patients with high risk GIST.

Association of IL18 genetic polymorphisms with increased risk of Biliary atresia susceptibility in Southern Chinese children

Biliary atresia (BA) has complex genetic etiology, characterized by different levels of hepatic fibrosis after the Kasai procedure and immune responses to the bile duct. As an activator of the two most important inflammatory cells in Biliary atresia (T cells and NK cells), IL-18 is significantly increased in BA patients. This study aims to investigate the association of Interleukin 18(IL-18) with the susceptibility to BA. We examined the association of three polymorphisms (rs549908, rs187238 and rs1946518 in IL-18) and BA susceptibility in a Southern Chinese population composed of 506 cases and 1473 controls. SNP rs187238 and rs1946518 were identified as associated with BA. Interestingly, we also observed that the intragenic synergistic epistasis between SNPs rs187238 and rs1946518 boosting the risk to BA by logistic regression and Multifactor dimensionality reduction (MDR) analysis. This study provides for the first time a direct evidence to support IL-18 as a susceptibility gene for the disease in southern Chinese children.

Downregulation of Hes1 expression in experimental biliary atresia and its effects on bile duct structure

AIM

To analyze the expression and function of the Notch signaling target gene Hes1 in a rhesus rotavirus-induced mouse biliary atresia model.

METHODS

The morphologies of biliary epithelial cells in biliary atresia patients and in a mouse model were examined by immunohistochemical staining. Then, the differential expression of Notch signaling pathway-related molecules was investigated. Further, the effects of the siRNA-mediated inhibition of Hes1 expression were examined using a biliary epithelial cell 3D culture system.

RESULTS

Both immature (EpCAM⁺) and mature (CK19⁺) biliary epithelial cells were detected in the livers of biliary atresia patients without a ductile structure and in the mouse model with a distorted bile duct structure. The hepatic expression of transcripts for most Notch signaling molecules were significantly reduced on day 7 but recovered to normal levels by day 14, except for the target molecule Hes1, which still exhibited lower mRNA and protein levels. Expression of the Hes1 transcriptional co-regulator, RBP-Jκ was also reduced. A 3D gel culture system promoted the maturation of immature biliary epithelial cells, with increased expression of CK19⁺ cells and the formation of a duct-like structure. The administration of Hes1 siRNA blocked this process. As a result, the cells remained in an immature state, and no duct-like structure was observed.

CONCLUSION

Our data indicated that Hes1 might contribute to the maturation and the cellular structure organization of biliary epithelial cells, which provides new insight into understanding the pathology of biliary atresia.

Autoimmune liver disease-related autoantibodies in patients with biliary atresia

AIM

To investigate the prevalence and clinical significance of autoimmune liver disease (ALD)-related autoantibodies in patients with biliary atresia (BA).

METHODS

Sera of 124 BA patients and 140 age-matched non-BA controls were assayed for detection of the following autoantibodies: ALD profile and specific anti-nuclear antibodies (ANAs), by line-blot assay; ANA and anti-neutrophil cytoplasmic antibody (ANCA), by indirect immunofluorescence assay; specific ANCAs and anti-M2-3E, by enzyme linked immunosorbent assay. Associations of these autoantibodies with the clinical features of BA (i.e., cytomegalovirus infection, degree of liver fibrosis, and short-term prognosis of Kasai procedure) were evaluated by Spearman’s correlation coefficient.

RESULTS

The overall positive rate of serum autoantibodies in preoperative BA patients was 56.5%. ALD profile assay showed that the positive reaction to primary biliary cholangitis-related autoantibodies in BA patients was higher than that to autoimmune hepatitis-related autoantibodies. Among these autoantibodies, anti-BPO was detected more frequently in the BA patients than in the controls (14.8% vs 2.2%, P < 0.05). Accordingly, 32 (25.8%) of the 124 BA patients also showed a high positive reaction for anti-M2-3E. By comparison, the controls had a remarkably lower frequency of anti-M2-3E (P < 0.05), with 6/92 (8.6%) of patients with other liver diseases and 2/48 (4.2%) of healthy controls. The prevalence of ANA in BA patients was 11.3%, which was higher than that in disease controls (3.3%, P < 0.05), but the reactivity to specific ANAs was only 8.2%. The prevalence of ANCAs (ANCA or specific ANCAs) in BA patients was also remarkably higher than that in the healthy controls (37.9% vs 6.3%, P < 0.05), but showed no difference from that in patients with other cholestasis. ANCA positivity was closely associated with the occurrence of postoperative cholangitis (r = 0.61, P < 0.05), whereas none of the autoantibodies showed a correlation to cytomegalovirus infection or the stages of liver fibrosis.

CONCLUSION

High prevalence of autoantibodies in the BA developmental process strongly reveals the autoimmune-mediated pathogenesis. Serological ANCA positivity may be a useful predictive biomarker of postoperative cholangitis.

[Texture analysis based on contrast-enhanced MRI can predict treatment response to neoadjuvant chemotherapy of breast cancer]

Objective: To investigate whether texture analysis based on contrast-enhanced MRI can predict pathological complete response of locally advanced breast cancer undergoing neoadjuvant chemotherapy(NAC). Methods: Forty-seven patients with breast cancer undergone neoadjuvant chemotherapy from January 2015 to February 2016 were divided into pathological complete response (pCR) group or non-pathological complete response (non-pCR) group based on surgical pathology. Their parameters of texture analysis based on MRI before neoadjuvant chemotherapy and after 2 cycles of treatment were analyzed. Parameters(Energy, Entropy, Inertia, Correlation, Inverse Difference Moment)before and after 2 cycles of NAC between pCR and non-pCR groups were compared using Student t or Wilcoxon rank sum test. The diagnostic performance of different parameters was judged by the receiver-operating characteristic (ROC) curve analysis. Results: The post-NAC value was significantly different from that of pre-NAC (all P<0.05). Pre-treatment parameters (Energy, Entropy, Inertia, Correlation, Inverse Difference Moment) were 78.58×10(-5)(55.64×10(-5), 135.23×10(-5)), 10.06 ± 1.02, 7 993.91±2 428.10, (4.76±0.99) ×10(-5) and (18.10±4.13) ×10(-3) in pCR group, and 76.84×10(-5) (48.68×10(-5), 154.15×10(-5)), 10.28±1.26, 7 184.77 (4 938.03, 9 974.04), (5.21±2.01) ×10(-5) and (17.68±5.87) ×10(-3) in non-pCR group. No significant difference was found between both groups. (P>0.05 for all). At the end of the second cycle of NAC, parameters(Energy, Entropy, Inertia, Correlation, Inverse Difference Moment) were (542.11±361.04) ×10(-5,) 7.95±1.28, 16 765.08±97 06.56, (0.43±0.07) ×10(-5,) and (12.18±9.82) ×10(-3) in pCR group, and 133.00×10(-5) (79.80×10(-5,) 239.00×10(-5)), 9.29±1.46, 7 916.64(6 418.89, 10 934.40), (0.38±0.08) ×10(-5) and (14.80±5.06) ×10(-3) in non-pCR group. At the end of the second cycle of NAC, there was significant difference in the parameters (Energy, Entropy, Inertia, Correlation) and Δparameters (ΔEnergy, ΔEntropy, ΔInertia, ΔInverse Difference Moment) between both groups (P<0.05 for all). The area under curve (AUC) of post-treatment ΔEntropy was 0.81, which was the largest one among parameters. Sensitivity of ΔEntropy for predicting pCR was 75.0% and specificity was 85.7%, respectively. Conclusion: Texture analysis based on dynamic contrast-enhanced MRI can predict early treatment response in primary breast cancer.

Role of CD56-expressing immature biliary epithelial cells in biliary atresia

AIM: To analyze the clinical and pathological parameters and expression of the neural cell adhesion molecule (CD56) in patients with biliary atresia (BA).

METHODS: Established clinical laboratory markers of hepatic function, including enzyme activity, protein synthesis, and bilirubin metabolism, were evaluated in patients with BA and compared with those in patients with choledochal cysts and neonatal hepatitis. Pathological changes in tissue morphology and fibrosis were examined by histological and tissue collagen staining. Immunohistochemical staining for the biliary epithelial cell markers CD56 and CK19 together with the Notch signaling related molecules Notch1 and Notch2 was performed in the context of alterations in the structure of intrahepatic biliary ducts.

RESULTS: Differences in some clinical laboratory parameters among the three diseases examined were observed, but they did not correlate with the pathological classification of fibrosis in BA. Immunohistochemical staining showed the presence of CD56-positive immature bile ducts in most patients (74.5%) with BA but not in patients with choledochal cysts or neonatal hepatitis. The number of CD56-expressing cells correlated with disease severity, with more positive cells present in the later stages of liver damage (81.8% vs 18.2%). Furthermore, bile plugs were mainly found in CD56-positive immature biliary ducts. Notch signaling was a key regulatory pathway in biliary duct formation and played a role in tissue fibrosis. Notch1 was co-expressed in CD56-positive cells, whereas Notch2 was found exclusively in blood vessels in the portal area of patients with BA.

CONCLUSION: The maturation of biliary epithelial cells and the expression of Notch may play a role in the pathogenesis of BA.

Dendrimer encapsulation enhances anti-inflammatory efficacy of silver nanoparticles

BACKGROUND

Our previous studies revealed that silver nanoparticles (AgNPs) promoted wound healing in part through their anti-inflammatory actions. As recent reports also suggested anti-inflammatory effects of dendrimers, we therefore undertook this study using dendrimer as the delivery system for AgNP to explore any potential synergistic anti-inflammatory efficacy.

METHODS

Lipopolysaccharide (LPS) was added to cultured RAW264.7 and J774.1 cells to mimic in vitro inflammation condition, followed by the addition of either silver dendrimer nanocomposite (Ag-DNC), AgNPs, or dendrimer. The levels of inflammatory markers TNF-alpha and interleukin-6 were assessed using ELISA assay. Furthermore, in vivo effects such of Ag-DNC, AgNPs, or dendrimer were studied in a burn wound model in mice.

RESULTS

Our results confirmed that both naked dendrimer and AgNPs had anti-inflammatory properties. In in vitro study, Ag-DNC was shown to have the best anti-inflammatory efficacy than AgNPs or dendrimer alone. In-vivo experiments also indicated that animals in the Ag-DNC group had the fastest healing time with the least inflammation.

CONCLUSION

Our study would suggest that dendrimer could provide additional anti-inflammatory benefits and might be an excellent delivery system for silver nanoparticles for future clinical application.

Automated 3D segmentation of hippocampus based on active appearance model of brain MR images for the early diagnosis of Alzheimer's disease

AIM

To investigate the hippocampal regional deformation modes by means of a novel method of automatic segmentation for discriminating between Alzheimer's disease (AD) and normal aging; and to further provide the effective evidence for the early diagnosis of AD.

METHODS

Twenty AD patients and sixty healthy volunteers were included in this retrospective study. High-resolution structural volumetric images were obtained on a 3.0 T MR imaging system. Data were processed to create three-dimensional (3D) active appearance model (AAM) of hippocampus. Automatic recognition and 3D segmentation were carried out on both sides of the hippocampus in brain MR images of individuals with this model, and the hippocampal statistical shape model was established for AD group and control group. Student's t test was used to identify whether there was difference between AD group and control group in the hippocampal regional deformation detected by automatic segmentation, and to compare whether there was difference between the automated segmentation and the manual tracing for quantifying hippocampal volumes on left/right side of the same sex group of healthy volunteers and if there was genderwise difference. Pearson's Correlation test was employed to determine whether there was a correlation between automated segmentation and manual tracing for quantifying hippocampal volumes.

RESULTS

No significant difference was detected between automated segmentation and manual tracing for quantifying hippocampal volumes on left/right side of the same sex group of healthy volunteers (P>0.05). Further there was no significant genderwise difference (P>0.05). A very strong positive correlation existed between both methods for quantifying hippocampal volumes (denoted R(2) near 1.0, P<0.001). Noticeable atrophy of bilateral hippocampal head was found among twenty patients with AD through statistical shape model compared with control group (P<0.05), especially on the left where inward-deformation was significantly found.

CONCLUSION

This novel method of automated segmentation of the hippocampus based on AAM has been found to be reliable and accurate in our study, which may be an alternative to manual segmentation. The featured atrophy of hippocampal head can be regarded as an important biomarker for the early diagnosis of AD.

The fluorescence recovery of polydiacetylene/fluorophore vesicles by interaction with cetyltrimethylammonium bromide

Polydiacetylene (PDA) has been widely used as a biosensor candidate because it exhibits specific blue-red transition upon varied external stimulations, such as heat, pH, or mechanical pressure. We prepared mixed vesicles using the 10,12-pentacosadiynoic acid (PCDA) and fluorescence probe BO558, and investigated the interaction of surfactant with PCDA/BO558 vesicles. Experiments exhibited that the fluorescence of BO558 was significantly quenched owing to the ene-yne conjugated backbones in the PCDA vesicles. However, the fluorescence was gradually recovered in the presence of cetyltrimethylammonium bromide (CTAB) to the system. Meanwhile, the turbidity of the mixed solution decreased greatly with the increase of CTAB concentration. We investigated the mechanism of the fluorescence quenching and recovery in the system of PCDA/BO558 vesicles and CTAB by UV-vis spectrum, stable fluorescence, transmission electron microscopy. The morphology of vesicles transformed with the change of surfactant concentration.

Ullrich scleroatonic muscular dystrophy is caused by recessive mutations in collagen type VI

Ullrich syndrome is a recessive congenital muscular dystrophy affecting connective tissue and muscle. The molecular basis is unknown. Reverse transcription-PCR amplification performed on RNA extracted from fibroblasts or muscle of three Ullrich patients followed by heteroduplex analysis displayed heteroduplexes in one of the three genes coding for collagen type VI (COL6). In patient A, we detected a homozygous insertion of a C leading to a premature termination codon in the triple-helical domain of COL6A2 mRNA. Both healthy consanguineous parents were carriers. In patient B, we found a deletion of 28 nucleotides because of an A --> G substitution at nucleotide -2 of intron 17 causing the activation of a cryptic acceptor site inside exon 18. The second mutation was an exon skipping because of a G --> A substitution at nucleotide -1 of intron 23. Both mutations are present in an affected brother. The first mutation is also present in the healthy mother, whereas the second mutation is carried by their healthy father. In patient C, we found only one mutation so far-the same deletion of 28 nucleotides found in patient B. In this case, it was a de novo mutation, as it is absent in her parents. mRNA and protein analysis of patient B showed very low amounts of COL6A2 mRNA and of COL6. A near total absence of COL6 was demonstrated by immunofluorescence in fibroblasts and muscle. Our results demonstrate that Ullrich syndrome is caused by recessive mutations leading to a severe reduction of COL6.

[Determination of angiotensin-converting enzyme activity by micellar electrokinetic capillary chromatography]

A sensitive and rapid method was developed for angiotensin-converting enzyme (ACE) activity determination by micellar electrokinetic capillary chromatography (MECC). MECC was carried out to separate and quantify the products of the enzymatic reacting using Hip-Leu-His as the substrate in 20 mmol/L boric acid-borate buffer (pH 9.0) including 50 mmol/L SDS as the run buffer at an applied voltage of 8.1 kV. The electrophoresis was monitored at 228 nm, and completed in 6 minutes. The detection limits of ACE activity was 5 pmol/min(signal to noise ratio was 2).

A Bethlem myopathy Gly to Glu mutation in the von Willebrand factor A domain N2 of the collagen alpha3(VI) chain interferes with protein folding

A single G1679E mutation in the amino-terminal globular domain N2 of the alpha3 chain of type VI collagen was found in a large family affected with Bethlem myopathy. Recombinant production of N2 ( approximately 200 residues) in transfected mammalian cells has now been used to examine the possibility that the mutation interfered with protein folding. The wild-type form and a G1679A mutant were produced at high levels and shown to fold into a stable globular structure. Only a small amount of secretion was observed for mutants G1679E and G1679Q, which apparently were efficiently degraded within the cells. Homology modeling onto the related von Willebrand factor A1 structure indicated that substitution of G1679 by the bulky E or Q cannot be accommodated without considerable changes in the folding pattern. This suggests protein misfolding as a molecular basis for this particular mutation in Bethlem myopathy, in agreement with radioimmunoassay data showing reduced levels of domain N2 in cultured fibroblasts from two patients.

[Immunoaffinity purification of specific immunoglobulin from egg yolk]

Immunoaffinity column (Sepharose-4B) was made with bovine serum albumin (BSA) and used to isolate anti-BSA antibody from egg laid by hens which were immunized with BSA. Polyclonal antibody was eluted under different conditions (pH 5.0-2.8) because of its different affinity against antigen. SDS-PAGE and double-immunodiffusion analysis confirmed that antibody isolated from egg yolk was electrophoretically pure and specific. According to the separation aim in this paper, the final elution buffer was 0.1 mol/L glycine-HCl buffer, pH 2.8. The final antibody yield was higher than 90%. As a new development in chromatographic media, POROS has its maximum pressure limit of 21 MPa. It has been widely used because of its high performance, high flow and large capacity. The sugar residue of the antibody was then oxidized and coupled to the hydrazide activated POROS HY. Pure targeted protein (BSA) was obtained through the POROS HY column. The tendency of specific antibody production was investigated during the immunization period. The amount of specific antibody has increased obviously after boost immunization.

Complete exon-intron organization of the mouse fibulin-1 gene and its comparison with the human fibulin-1 gene

Fibulin-1 is a 90 kDa calcium-binding protein present in the extracellular matrix and in the blood. Two major variants, C and D, differ in their C-termini as well as the ability to bind the basement membrane protein nidogen. Here we characterized genomic clones encoding the mouse fibulin-1 gene, which contains 18 exons spanning at least 75 kb of DNA. The two variants are generated by alternative splicing of exons in the 3' end. By searching the database we identified most of the exons encoding the human fibulin-1 gene and showed that its exon-intron organization is similar to that of the mouse gene.

CA repeat polymorphism of the COL6A3 gene on chromosome 2q37

A CA dinucleotide repeat has been identified in an intron of the human alpha3(VI) collagen gene (COL6A3) located on chromosome 2q37. Analysis of 100 chromosomes in unrelated Caucasians has demonstrated the existence of eight alleles, and the allelic frequencies have been determined.

Missense mutation in a von Willebrand factor type A domain of the alpha 3(VI) collagen gene (COL6A3) in a family with Bethlem myopathy

The Bethlem myopathy is a rare autosomal dominant proximal myopathy characterized by early childhood onset and joint contractures. Evidence for linkage and genetic heterogeneity has been established, with the majority of families linked to 21q22.3 and one large family linked to 2q37, implicating the three type VI collagen subunit genes, COL6A1 (chromosome 21), COL6A2 (chromosome 21) and COL6A3 (chromosome 2) as candidate genes. Mutations of the invariant glycine residues in the triple-helical domain-coding region of COL6A1 and COL6A2 have been reported previously in the chromosome 21-linked families. We report here the identification of a G-->A mutation in the N-terminal globular domain-coding region of COL6A3 in a large American pedigree (19 affected, 12 unaffected), leading to the substitution of glycine by glutamic acid in the N2 motif, which is homologous to the type A domains of the von Willebrand factor. This mutation segregated to all affected family members, to no unaffected family members, and was not identified in 338 unrelated Caucasian control chromosomes. Thus mutations in either the triple-helical domain or the globular domain of type VI collagen appear to cause Bethlem myopathy.

Costs of polio immunization days in China: implications for mass immunization campaign strategies

Ten provinces of China were selected to estimate the cost per immunization of the 1994-95 national immunization days (NIDs) at five levels (e.g. province, prefecture, county, township and village). Personnel costs accounted for the largest overall share of costs (39 per cent), followed by publicity and promotion costs (27 per cent), and logistic costs (15 per cent). Without consideration of vaccine costs, the major part of NID expenses were shouldered at the township level, which paid for 47 per cent of all incremental costs, while county and village level covered 28 per cent and 18 per cent respectively. Estimation of average costs per immunization was 2.86 RMB yuan, or $0.34, including vaccine costs, buildings and equipment amortization and salaries at all levels. The factors affecting average cost of NID included the output volume, socio-economic development and geographic features. Various approaches were recommended: to intensify the productivity of time and staff, to employ alternative inexpensive manpower resources, to make the best use of publicity and social promotion, the expansion of the age groups and utilization of multi-intervention strategies. Good planning at township level was a decisive factor to ensure an effective NID conducted in an efficient manner. The average cost of China's NID was the lowest among all mass immunization campaigns ever documented. Much of the reduced average cost was attributable to economies of scale.

[Study on the immunization status of children and risk factors in floating population]

In order to reveal immunization status of children in migrating families and its related risk factors, a study was conducted in Beijing, Inner Mongolia and Fujian from August to November, 1996. Results showed that the overall coverage with BCG, OPV, DPT and MV was 34.26% (95% CI: 29.75%-38.94%). Many factors influenced the immunization status of floating children which mainly consisted of a) regular searching for new coming floating children conducted by EPI staff, b) awareness of parents on the number of the total EPI-targeted vaccines, c) home as the place that the child was born, d) the length did the child's mother stay at the place, e) how well did the parents comply to the vaccination and f) The type of hospital was chosen when seeing a doctor.

Status of the eradication of indigenous wild poliomyelitis in the People's Republic of China

A large nationwide outbreak occurred in 1989-1990 in China, in which nearly 10,000 poliomyelitis cases were reported. After two rounds of oral poliovirus vaccine (OPV) supplemental activity in nearly every province in the 1992-1993 winter season, no wild poliovirus was detected in 1993 in 22 provinces in the middle of China that contained 86% of the population. During the first national immunization days (NIDs) conducted in December 1993 and January 1994, 83 million children 0-47 months of age were immunized. In 1994, wild poliovirus was identified in only 6 of 2397 children with stool specimens tested. After a second NID in December 1994 and January 1995, no wild poliovirus was detected in 1995 despite a very high level of virus surveillance. In summary, double-round mass supplemental OPV immunizations in children 0-3 years old in two consecutive winters eliminated wild poliovirus from 23% of the world's population (1.2 billion people).

Effect of target age of supplemental immunization campaigns on poliomyelitis occurrence in China

The World Health Organization recommends conducting supplemental immunization activities to eradicate poliomyelitis by the year 2000. Although effective in eliminating poliomyelitis from the Americas, supplemental campaigns require substantial resources. To assess differential campaign effectiveness in eliminating this disease, poliomyelitis occurrence was compared in counties in China that targeted children <3 versus <4 years of age. Counties that targeted children <3 years of age reported poliomyelitis more frequently after the campaigns. This association was observed even after accounting for the effects of previous poliomyelitis occurrence, urban versus rural setting, and population density. While several limitations emphasize the preliminary nature of these findings, these data support targeting the widest possible age group of susceptible children to ensure maximum effectiveness in eliminating poliomyelitis. Thus, while reducing the target age of these activities may result in considerable resource savings, such campaigns may not be as effective in eliminating poliomyelitis.

Surveillance for polio eradication in the People's Republic of China

A case-based virus surveillance system for wild poliovirus in China was developed. By 1993, all 30 provincial immunization units and, by 1994, all 29 provincial laboratories were sending computerized data to the national level. In 1993, a county-level, computerized map was operationalized that permitted visual monitoring of the progress of the polio eradication program every month by county. In 1993, wild poliovirus type 1 was detected in 8 provinces. Wild poliovirus mainly caused clusters of polio cases identified by a surveillance system that detected primarily clinical polio in children <5 years old (1 stool sample was collected on approximately 50% of reported cases). By 1995, the surveillance system had reached certification-like levels (80% of acute flaccid paralysis [AFP] patients with 2 stool specimens and AFP case rate of 1/100,000 children <15 years old). No indigenous wild poliovirus was detected in 1995. This general case-based model can be applied to measles and other important diseases, and may then lead to a more rapid decrease in adverse health outcomes.

[Social burden caused by poliomyelitis]

Social burden caused by paralyzed poliomyelitis was analysed, using data from a Sampling Survey of Handicapped People in China, in 1987. The study results showed: 29.94% of 1707 handicapped polio victims aged 6 or over were not able to go to school; 44.23% of them could not take care of their daily life; 36.32% of them could not play out-door and do shopping; 2.58% of them could not normally communicate with others. 84.53% of the 1487 handicapped victims caused by polio aged 15 or over wholly or partly lost their working ability. We also compared handicapped people's employment rate and the status of marriage with non-handicapped people. Data showed that the employment rate and the number of married handicapped polio victims were remarkably lower then those non-handicapped people.

Deposition of collagen VI in the extracellular matrix during mouse embryogenesis correlates with expression of the alpha 3(VI) subunit gene

Collagen VI is a microfibrillar component of the extracellular matrix that is predicted to have an important structural role in matrix organization and a biological function in mediating cell-matrix interactions. Secreted collagen VI molecules are composed of three distinct subunits, the alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains. To determine when, and in which tissues, collagen VI is likely to have a role in embryonic processes, we have analyzed the expression patterns of the three subunit chains during postimplantation mouse development by reverse transcriptase-PCR (RT-PCR), in situ hybridization, and immunofluorescence. No collagen VI protein could be detected in the mouse embryo until Day 11.5 of gestation, when low levels were localized within the mesoderm layer of the visceral yolk sac, the subepidermal matrix of branchial arches, and the vessel wall of the dorsal aorta. Levels of collagen VI mRNA and protein increased during the period from Days 12.5 to 14.5 in the visceral yolk sac, subepidermal mesenchyme, lung, gut, meninges, muscle, perichondrium, and vertebral column. The cartilage matrix of ribs and developing long bones was not stained with collagen VI antisera, but pericellular staining of chondrocytes was seen in both tissues. Low levels of collagen VI mRNA and protein were seen in the fetal liver except for the connective tissue of the liver capsule, which was highly stained. Collagen VI was first detected at significant levels in the developing heart on Day 14.5. These data demonstrate a tissue-specific onset of collagen VI synthesis and deposition in the extracellular matrix of developing mouse embryos at a much later stage of development than that reported for fibronectin or collagen I. Sensitive RT-PCR assays showed that alpha 1(VI) and alpha 2(VI) mRNAs were amplified from extracts of embryonic tissues as early as Day 7.5, while alpha 3(VI) mRNA was not detected until Day 10.5. Expression of the alpha 3(VI) gene immediately preceded the appearance of collagen VI protein in embryonic tissues. This correlation is consistent with the proposal that expression of alpha 3(VI) chains regulates the formation and secretion of collagen VI trimers and collagen VI matrix deposition during development.

[Economic burden of poliomyelitis]

Economic burden that caused by paralyzed and fatal poliomyelitis was described to provide basic data for evaluation. The study showed: the average costs for treatment, recovery and rehabilitation were 1612.6 yuan, 921.9 yuan and 1112.2 yuan per case, respectively. The total economic loss due to all new victims and handicapped cases of polio was 1.99 billion yuan in 1993 in China.

[Epidemiological analysis of poliomyelitis cases in 1994, China]

In 1994, the number of reported polio cases was 307 in China. This number was 53% lower than that in 1993, and was the lowest record ever in China. In 1994, the distribution of polio cases was highly dispersed and the number of outbreak was reduced obviously. Of 225 counties which reported polio cases in 1994, polio outbreak occured in 2 counties. Cases due to polio outbreak accounted for 4.2% of the total cases. The distribution of polio wild virus was narrow but the regional difference still existed. In the southeast, high risk region for polio consisting Guangdong, Hainan, Fujian three provinces, the number of polio cases decreased remarkably in 1994. On the contrary, in the southwest region which, consisting Guangxi, Yunnan, Guizhou, Sichuan four provinces, the number of polio cases increased obviously, accounted for approximately a half of the total number in 1994. During the coming 1 to 2 years, we should emphasis on these regions and provinces where high incidence was noticed in our polio eradication program. Those provinces should include Xinjiang, Fujian. Hubei three provinces that polio wild virus was identified in 1994, and Guangxi, Sichuan, Guizhou, Yunnan in the south west region as well. We should further increase Polio vaccination coverage of children especially floating and unplanned ones through strengthening routine immunization and carring out new national immunization day activity.

[Evaluation of acute flaccid paralysis (AFP) surveillance system in 1994]

Increased by 40.2% compared with 1993, 3142 acute flaccidparalysis cases were reported from AFP surveillance system in 1994. A total number of 1297 counties had AFP cases reported, accounting for 45.1% of total amount of counties. Out of 3142 AFP cases, 307 were confirmed, coming from 225 counties. For children under 15 years old, the reported AFP incidence was 1.1/10(5), non-polio AFP rate was 0.83/10(5), much higher than 0.37/10(5), in 1993. 48.5% of the total AFP cases had double stool specimen taken within 0-14 days after paralysis. 79% AFP cases had been investigated within 48 hours after being reported. Some of the major monitoring indicators of AFP surveillance system were close to the WHO criterion, but the percentage of AFP cases reported within 48 hours of careseeking and AFP cases with follow-up visit after 60-70 days of paralysis were very low. Furthermore, 77.9% of the confirmed cases were diagnosea clinically by residual paralysis, so did the 46.4% of discarded cases. It is in urgent need to increase the percentage of cases classified by laboratory test.

[Seroepidemiological surveillance and methodological study of pertussis, diphtheria and tetanus]

In this paper, we studied the diagnostic method of DPT using PA method developed by Japanese National Institute of Health (NIH) in 1993-1994, meanwhile we surveyed the antibody level of DPT. We collected 900 sera samples and 300 sera samples from Hebei province in 1993 and 1994. The result showed that PA method was simple, reliable and easy to observe, which can make up the shortages existed in PHA method. The antitoxin titers obtained by the PA method correlated well with the PHA method, while the latter was more sensitive. The antibody level of pertussis obtained through PA method did not correlate well with MA method. The result also showed that the antibody level of DPT was not high, with a 95.0% positive rate of pertussis. The rate of titers higher than 1:320 was 4.7% with GMT 1:121; the positive rate of diphtheria was 62.9% with GMT 0.0280 IU/ml, in 1993 the positive rate of tetanus was 70.5% with GMT 0.1410 IU/ml, in 1994 the positive rate was 75.7% with GMT 0.3281 IU/ml. The titers in urban areas were higher than in rural areas and a decrease was observed with the increase of age. The titers in males was similar to in females. According to this result, a routine immunization followed by booster program should be emphasized.

Developmental expression and molecular cloning of REMP, a novel retinal epithelial membrane protein

The retinal pigment epithelium (RPE), like other transport epithelia, has a polarized distribution of membrane and cytoskeletal proteins. The establishment of a polarized phenotype is an essential step in the differentiation of the RPE and the development and maintenance of visual function. Using a monoclonal antibody (MAb 3C4) we have identified a novel membrane protein that is uniquely expressed in chick RPE. We have referred to this protein as REMP for retinal epithelial membrane protein. In these studies we characterized the expression and distribution of this protein during embryonic development and determined its primary structure by cDNA cloning. The developmental expression of REMP was examined by immunocytochemical localization. REMP was first detected in the chick RPE at Embryonic Day 5 (E5) in both apical and basolateral membranes. By E14 the distribution of REMP was restricted to the basolateral surface of the RPE cells. Biochemical fractionation and surface labeling of RPE cells suggested that REMP was an integral protein. The gene encoding REMP was isolated from an E15 chick RPE cDNA library, cloned into lambda gt11, and screened with MAb 3C4. The cDNA was sequenced and found to contain one 1350-bp open reading frame encoding for a 450-amino-acid protein. The deduced amino-acid sequence of REMP shares 32.9% identity with MCT1, a monocarboxylate transporter (Garcia, Goldstein, Pathak, Anderson, and Brown, Cell, 76, 865-873, 1994). By Northern blot analysis, REMP mRNA was detected only in RPE cells. There was an increase in the expression REMP transcript during development but when RPE cells were grown in primary culture the expression of REMP was turned off. The unique expression of REMP in the RPE in vivo would suggest a role for this protein in development and maintenance of normal retinal function.

Expression of collagen alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains in the pregnant mouse uterus

The alpha 1, alpha 2, and alpha 3 chains of collagen VI and mRNAs for these chains were localized in the female mouse reproductive tract by immunofluorescence and in situ hybridization. High levels of collagen VI protein and mRNAs were present in the endometrium and myometrium of the uterus up to Day 4.5 of pregnancy. After embryo implantation, reduction in collagen VI protein within the decidualizing endometrium correlated with significantly reduced steady-state levels of alpha 1(VI), alpha 2(VI), and alpha 3(VI) mRNAs, indicating either transcriptional down-regulation of collagen VI gene expression or decreased stability of transcripts. High levels of alpha 1(V1) and alpha 2(VI) mRNAs, but not alpha 3(VI) mRNA, in cells surrounding the uterine epithelium in the mesometrial region did not correlate with deposition of collagen VI protein in this region. These data are consistent with an important role of alpha 3(VI) in assembly of collagen VI heterotrimers. However, distinct immunostaining with antiserum to alpha 2(VI) chains in the extracellular matrix immediately beneath the uterine epithelium may indicate that alpha 2(VI) chains are deposited without the alpha 1(VI) or alpha 3(VI) collagen chains. No collagen VI protein or mRNAs were detected in any tissue layers of the embryo on Days 5.5 or 6.5 of gestation.

Fibulin-2 (FBLN2): human cDNA sequence, mRNA expression, and mapping of the gene on human and mouse chromosomes

Fibulin-2 is a new extracellular matrix protein that we recently identified by characterizing mouse cDNA clones. Fibulin-2 mRNA is prominently expressed in mouse heart tissue and is present in low amounts in other tissues. In this study, we isolated and sequenced a 4.1-kb human fibulin-2 cDNA, which encoded a mature protein of 1157 amino acids preceded by a 27-residue signal sequence. The predicted polypeptide contains three consecutive anaphylatoxin-related segments (domain I) in its central region followed by 10 EGF-like repeats (domain II), 9 of which have a consensus sequence for calcium binding. The 408-residue N-terminal region consists of two separate subdomains, a cysteine-rich segment of 150 residues (Na subdomain) and a cysteine-free segment with a stretch of acidic amino acids (Nb subdomain). The 115-residue C-terminal segment (domain III) is similar to the C variant of fibulin-1. The amino acid sequences of the human and mouse fibulin-2 share approximately 90% identity in domains Na, I, II, and III but only 62% identity in domain Nb. The human cDNA lacks an EGF-like repeat, which is alternatively spliced in the mouse cDNA clones, and a potential cell-binding Arg-Gly-Asp sequence found in the Nb domain of the mouse counterpart. Northern blot analysis of mRNA from various human tissues reveals an abundant 4.5-kb transcript in heart, placenta, and ovary tissue. The expression pattern differs from that of fibulin-1. The fibulin-2 gene was localized by in situ hybridization to the p24-p25 region of human chromosome 3 and to the band D-E of mouse chromosome 6.

The fibulin-1 gene (FBLN1) is located on human chromosome 22 and on mouse chromosome 15

Fibulin-1 is a calcium-binding glycoprotein present in the extracellular matrix and in the serum. The gene coding for fibulin-1 (FBLN1) was located by in situ hybridization of 3H-labeled cDNA probes to human and mouse metaphase chromosomes. The gene was assigned to the q13.2-q13.3 region of human chromosome 22 and to the E-F band of mouse chromosome 15. This finding extends the evolutionary conservation between human chromosome 22 and mouse chromosome 15.

Recombinant expression and structural and binding properties of alpha 1(VI) and alpha 2(VI) chains of human collagen type VI

Full-length alpha 1(VI) and alpha 2(VI) cDNAs in an eukaryotic expression vector were used to obtain stably transfected human kidney cell clones and to purify these collagen-VI chains in substantial quantities from the culture medium. Both chains appeared mainly as monomers together with some dimers that were disulfide linked through their C-terminal globular domains. Despite sufficient hydroxylation of proline and lysine residues, the chains did not form a triple-helix, as shown by electronmicroscopy, CD spectra and pepsin sensitivity. Digestion of the chains with bacterial collagenase released the N-terminal and C-terminal globular domains, which were identified by their size and partial sequences. They showed a substantial content of alpha-helical conformation and a distinct globular structure after rotary shadowing. Antibodies could be raised that distinguished between the two chains and reacted with the globular domains. The alpha 2(VI) but not the alpha 1(VI) chain showed binding to a heparan sulfate proteoglycan (perlecan), fibronectin and pepsin-solubilized collagen VI. Purified globular domains did not bind these ligands indicating the localization of binding sites within the triple-helical domain. Both chains showed a distinct affinity for heparin but failed to bind to various collagen types.

Structure and expression of fibulin-2, a novel extracellular matrix protein with multiple EGF-like repeats and consensus motifs for calcium binding

A new protein, fibulin-2, was predicted from sequence analysis of cDNA clones obtained from a mouse fibroblast library. This protein consists of a 1195-residue polypeptide preceded by a 26-residue signal peptide. The COOH-terminal region of 787 amino acids contained three anaphylatoxin-related segments (domain I), 11 EGF-like repeats (domain II), 10 of which had a consensus motif for calcium-binding, and a 115-residue globular domain III. Except for two additional EGF-like repeats, this COOH-terminal region showed 43% sequence identity with the previously described fibulin-1 (BM-90). The NH2-terminal 408 residues, unique to fibulin-2, showed no sequence homology to other known proteins and presumably form two additional domains that differ in their cysteine content. Recombinant fibulin-2 was produced and secreted by human cell clones as a disulfide-bonded trimer. Rotary shadowing visualized the protein as three 40-45 nm long rods which are connected at one end in a globe-like structure. No significant immunological cross-reaction could be detected between fibulin-1 and fibulin-2. Production of the fibulin-2 was demonstrated by Northern blots and radioimmunoassay in fibroblasts but not in several tumor cell lines. Together with the observation that the serum level of fibulin-2 is 1,000-fold lower than that of fibulin-1, the data indicate that these two isoforms are not always coordinately expressed. This is also suggested by Northern blots of tissue mRNAs and by immunofluorescence localizations using mouse tissues. The latter studies also demonstrated an extracellular localization for fibulin-2 in basement membranes and other connective tissue compartments.

Sequence of extracellular mouse protein BM-90/fibulin and its calcium-dependent binding to other basement-membrane ligands

Partial sequence comparisons have recently indicated that two extracellular components, fibulin from human placenta and BM-90 from a basement-membrane-producing mouse tumor, are either identical or closely related proteins. In this study, a complete sequence analysis of mouse BM-90 cDNA showed a 539-residue N-terminal core structure (domains I and II), which was 85% identical with the same core structure of human fibulin. A 137-residue C-terminal sequence (domain III) was unique for BM-90 and could also be identified by Edman degradation. This suggested a novel splice product, variant D, which is characteristic for the mouse tumor. A second 117-residue C-terminal sequence (domain III) was identified in additional mouse cDNA clones and showed 91% identity with the region specific for variant C of fibulin. Northern blots using mouse cells demonstrated two mRNA species, 2.7 kb and 2.3 kb, which encoded the variants D and C, respectively. The sequence of BM-90/fibulin indicates the presence of nine epidermal-growth-factor-like repeats in the core domain-II structure, eight of which contain consensus motifs for calcium binding. This binding is apparently important for the interaction of BM-90 with laminin and nidogen and for some weaker interactions with collagen IV. Further binding of BM-90 was demonstrated to fibronectin and BM-90 itself, but did not depend on calcium. Major binding sites for BM-90 were identified at a C-terminal segment of laminin A chain and at the N-terminus of nidogen. The broad interaction repertoire of BM-90 is comparable to that of nidogen and both proteins may have similar roles as connecting elements in the extracellular matrix.

Cloning and sequence analysis of cDNAs encoding the alpha 1, alpha 2 and alpha 3 chains of mouse collagen VI

cDNA clones encoding the alpha 1, alpha 2 and alpha 3 chains of mouse collagen VI have been isolated by screening cDNA libraries with the corresponding human probes. The composite cDNAs for the alpha 1, alpha 2, and alpha 3 chains are 2.5, 1.6 and 2.9 kb in size respectively. The alpha 1 and alpha 2 cDNAs encode the C-terminal portions of the chains as well as the entire 3'-untranslated regions, while the alpha 3 cDNAs encode a central segment of 959 amino acids flanking the triple-helical domain. The deduced amino acid sequences share 86-88% identity with the human counterparts and 67-73% identity with the chicken equivalents. Alignment of the deduced amino acid sequences of mouse, human and chicken collagens reveal that the key features of the protein, including the cysteine residues, imperfections in the Gly-Xaa-Xaa regions, Arg-Gly-Asp sequences and potential N-glycosylation sites, are mostly conserved.

Hyperglycemic glucose concentrations up-regulate the expression of type VI collagen in vitro. Relevance to alterations of peripheral nerves in diabetes mellitus

Electron microscopy of peripheral nerves obtained from two diabetic patients revealed large deposits of microfibrils and the presence of Luse bodies in the vicinity of perineurial cells. Microfibrils were found to accumulate also in the sciatic nerves of diabetic BB rats; these microfibrillar deposits were shown to contain type VI collagen by immunoelectron microscopy. Connective tissue cells cultured from rat sciatic nerves were exposed to high glucose concentrations. High glucose concentrations up-regulated the mRNA steady-state levels of alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains of type VI collagen and caused accumulation of type VI collagen-containing fibrils in the cultures. Immunostaining and in situ hybridizations demonstrated that perineurial cells, Schwann cells, and fibroblasts expressed type VI collagen at the mRNA and protein levels. The results suggest that the turnover and supramolecular assembly of type VI collagen are perturbed in diabetic nerves and that glucose per se increases the expression of type VI collagen in vitro.

The large non-collagenous domain (NC-1) of type VII collagen is amino-terminal and chimeric. Homology to cartilage matrix protein, the type III domains of fibronectin and the A domains of von Willebrand factor

Type VII collagen, the major component of anchoring fibrils, consists of a central collagenous triple-helical segment flanked by non-collagenous domains, NC-1 and NC-2. In this study, we examined the domain organization of human type VII collagen through analysis of deduced amino acid sequences derived from cloned complementary and genomic DNAs, as compared to peptide segments derived from amniotic membrane type VII collagen. The results revealed that the peptide segments derived from the NC-1 domain of type VII collagen could be assigned to the 5' portion of the composite cDNA, indicating that NC-1 resides at the amino terminal end of the molecule. Several sub-domains with homology to adhesive molecules were also identified within NC-1. These protein domains may confer adhesive properties to NC-1, thereby facilitating the binding of type VII collagen to the lamina densa in the cutaneous basement membrane and the anchoring plaques within the dermis.

Cloning and chromosomal location of human alpha 1(XVI) collagen

We have characterized cDNA clones that encode a newly discovered collagenous polypeptide. A 4-kilobase (kb) cDNA clone was initially isolated by screening a human fibroblast cDNA library with a probe encoding the collagenous domain of the human alpha 3(VI) collagen. Subsequent screening of another fibroblast cDNA library yielded overlapping clones having a total length of 5.4 kb, which contained an open reading frame of 1603 amino acids including a 21-amino acid signal peptide. The predicted polypeptide consists of 10 collagenous domains 15-422 amino acids long, which were interspersed with 11 noncollagenous (NC) domains. Except for a large N-terminal NC11 domain of 312 residues, most of the NC domains were short (11-39 residues) and cysteine-rich. The overall structural arrangement differed significantly from other known collagen chains. Further analysis indicated that the deduced polypeptide exhibited several structural features characteristically seen in members of the fibril-associated collagen, types IX, XII, and XIV. In addition, the cysteine-rich motifs in the NC domains resembled those found in the cuticle collagen of Caenorhabditis elegans. Northern blot analyses showed hybridization of the cDNA to a 5.5-kb mRNA in human fibroblasts and keratinocytes. The gene was localized by in situ hybridization to band p34-35 of human chromosome 1. The data clearly support the conclusion that the cDNA encodes a collagen chain that has not been previously described. We suggest that the cDNA clones encode the alpha 1 chain of type XVI collagen.

The exon organization of the triple-helical coding regions of the human alpha 1(VI) and alpha 2(VI) collagen genes is highly similar

The alpha 1(VI) and alpha 2(VI) chains, two of the three constituent chains of type VI collagen, are highly similar in size and domain structure. They are encoded by single-copy genes residing in close proximity on human chromosome 21. To study the evolution of the type VI collagen genes, we have isolated and characterized genomic clones coding for the triple-helical domains of the human alpha 1(VI) and alpha 2(VI) chains, which consist of 336 and 335 amino acid residues, respectively. Nucleotide sequencing indicates that, in both genes, the exons are multiples of 9 bp in length (including 27, 36, 45, 54, 63, and 90 bp) except for those encoding for regions with triple-helical interruptions. In addition, the introns are positioned between complete codons. The most predominant exon size is 63 bp, instead of 54 bp as seen in the fibrillar collagen genes. Of particular interest is the finding that the exon structures of the alpha 1(VI) and alpha 2(VI) genes are almost identical. A significant deviation is that a segment of 30 amino acid residues is encoded by two exons of 54 and 36 bp in the alpha 1(VI) gene, but by a single exon of 90 bp in the alpha 2(VI) gene. The exon arrangement therefore provides further evidence that the two genes have evolved from tandem gene duplication. Furthermore, comparison with the previously reported gene structure of the chick alpha 2(VI) chain indicates that the exon structure for the triple-helical domain of the alpha 2(VI) collagen is strictly conserved between human and chicken.

Mosaic structure of globular domains in the human type VI collagen alpha 3 chain: similarity to von Willebrand factor, fibronectin, actin, salivary proteins and aprotinin type protease inhibitors

Human collagen alpha 3(VI) chain mRNA (approximately 10 kb) was cloned and shown by sequence analysis to encode a 25 residue signal peptide, a large N-terminal globule (1804 residues), a central triple helical segment (336 residues) and a C-terminal globule (803 residues). Some of the sequence was confirmed by Edman degradation of peptides. The N-terminal globular segment consists of nine consecutive 200 residue repeats (N1 to N9) showing internal homology and also significant identity (17-25%) to the A domains of von Willebrand Factor and similar domains present in some other proteins. Deletions were found in the N3 and N9 domains of several cDNA clones suggesting variation of these structures by alternative splicing. The C-terminal globule starts immediately after the triple helical segment with two domains C1 (184 residues) and C2 (248 residues) being similar to the N domains. They are followed by a proline rich, repetitive segment C3 of 122 residues, with similarity to some salivary proteins, and domain C4 (89 residues), which is similar to the type III repeats present in fibronectin and tenascin. The most C-terminal domain C5 (70 residues) shows 40-50% identity to a variety of serine protease inhibitors of the Kunitz type. The whole sequence contains 29 cysteines which are mainly clustered in short segments connecting domains N1, C1, C2 and the triple helix, and in the inhibitor domain. Five putative Arg-Gly-Asp cell-binding sequences are exclusively localized in the triple helical segment.(ABSTRACT TRUNCATED AT 250 WORDS)