NOVA1 promotes SMN2 exon 7 splicing by binding the UCAC motif and increases SMN protein expression.

Spinal muscular atrophy (SMA) is a rare hereditary neuromuscular disease with a high lethality rate in infants. Variants in the homologous genes survival of motor neuron (SMN)1 and SMN2 have been reported to be SMA pathogenic factors. Previous studies showed that a high inclusion rate of SMN2 exon 7 increased SMN expression, which in turn reduced the severity of SMA. The inclusion rate of SMN2 exon 7 was higher in neural tissues than in non-neural tissues. Neuro-oncological ventral antigen (NOVA) is a splicing factor that is specifically and highly expressed in neurons. It plays a key role in nervous system development and in the induction of nervous system diseases. However, it remains unclear whether this splicing factor affects SMA. In this study, we analyzed the inclusion of SMN2 exon 7 in different tissues in a mouse model of SMA (genotype smn-/-SMN22tg/0) and littermate controls (genotype smn+/-SMN22tg/0). We found that inclusion level of SMN2 exon 7 was high in the brain and spinal cord tissue, and that NOVA1 was also highly expressed in nervous system tissues. In addition, SMN2 exon 7 and NOVA1 were expressed synchronously in the central nervous system. We further investigated the effects of NOVA1 on disease and found that the number of neurons in the anterior horn of spinal cord decreased in the mouse model of SMA during postnatal days 1-7, and that NOVA1 expression levels in motor neurons decreased simultaneously as spinal muscular atrophy developed. We also found that in vitro expression of NOVA1 increased the inclusion of SMN2 exon 7 and expression of the SMN2 protein in the U87MG cell line, whereas the opposite was observed when NOVA1 was knocked down. Finally, point mutation and RNA pull-down showed that the UCAC motif in SMN2 exon 7 plays a critical role in NOVA1 binding and promoting the inclusion of exon 7. Moreover, CA was more essential for the inclusion of exon 7 than the order of Y residues in the motif. Collectively, these findings indicate that NOVA1 interacts with the UCAC motif in exon 7 of SMN2, thereby enhancing inclusion of exon 7 in SMN2, which in turn increases expression of the SMN protein.

Therapeutic strategies for flexor tendon healing by nanoparticle-mediated co-delivery of bFGF and VEGFA genes.

Tendon injuries are a common injury of musculocutaneous system. Due to the lack of sufficient cellularity and low growth factor activity, healing of disrupted digital flexor tendon is troublesome and the process is lengthy and ineffective. bFGF and VEGFA gene were proved to be responsible and critical for promoting tendon healing. How to continuously enhance expression of these genes is a challenge. In this study, we developed a combination therapeutic approach that corrects the fundamental problem underlying intrasynovial tendon healing with introduction of growth factor genes via non-viral vector nanoparticle. PLGA nanoparticles as vehicle were used to delivery bFGF+VEGFA genes into injured tendon tissues. The expression of bFGF and VEGFA was upregulated in the tenocytes after transfection. We injected nanoparticle/bFGF+VEGFA gene complexes into injured tendons producing sufficient amounts of these factors required during early tendon healing period. After treatment, the ultimate strength of repaired tendons treated with nanoparticle/bFGF+VEGFA plasmid complexes was significantly increased, and combination therapy could also enhance flexor tendon gliding function. Therefore, combination gene therapy via nanoparticles may be an effective biological strategy for tendon repair.

Pathological and ultrastructural observations and liver function analysis of Eimeria stiedai-infected rabbits.

To study the pathogenicity of Eimeria stiedai, sporulated oocysts were given orally to coccidian-free two-month-old New Zealand rabbits(1000±20g). After 30days, blood samples from the rabbit hearts were collected for routine blood tests, liver functions and four characteristics of blood coagulation. Additionally, specimens of the liver, bile duct and duodenum were collected to observe the changes in pathology and ultrastructure. E. stiedai severely restricted the growth and development of rabbits. Blood tests showed that glutamine transferase (GGT) and serum cholinesterase (ChE) were significantly different from the non-infected controls. Other extremely significant differences were observed in the biochemical indices of routine blood tests, liver function and four blood coagulation characteristics, indicating that the liver functions were significantly affected. Staining showed that, compared with the negative control group, the liver, bile duct and duodenum contained significant numbers of lesions, and organs and cell structures suffered severe damage in ultrastructure, which greatly affecting bodily functions. E. stiedai-infected rabbits model was successfully established, which might provide a theoretical basis for research on the pathogenesis of rabbit coccidia, and the diagnosis and prevention of coccidiosis in rabbits.

Identification of causative pathogens in mouse eyes with bacterial keratitis by sequence analysis of 16S rDNA libraries.

The clone library method using PCR amplification of the 16S ribosomal RNA (rRNA) gene was used to identify pathogens from corneal scrapings of C57BL/6-corneal opacity (B6-Co) mice with bacterial keratitis. All 10 samples from the eyes with bacterial keratitis showed positive PCR results. All 10 samples from the normal cornea showed negative PCR results. In all 10 PCR-positive samples, the predominant and second most predominant species accounted for 20.9 to 40.6% and 14.7 to 26.1%, respectively, of each clone library. The predominant species were Staphylococcus lentus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. The microbiota analysis detected a diverse group of microbiota in the eyes of B6-Co mice with bacterial keratitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The bacterial species detected in this study were mostly in accordance with results of studies on clinical bacterial keratitis in human eyes. Based on the results of our previous studies and this study, the B6-Co mouse should be considered a favorable model for studying bacterial keratitis.

Influence of three coccidiostats on the pharmacokinetics of florfenicol in rabbits.

In-feed Medication has been used for a long time to prevent coccidiosis, a worldwide protozoal disease in rabbits. Florfenicol (FFC) has been widely used in veterinary clinics for bacterial diseases treatment. Therefore, the use of combinations of coccidiostats with FFC in rabbits is common. In the present study, we aimed to evaluate the effect of three coccidiostats, sulfaquinoxaline (SUL), robenidine (ROB), and toltrazuril (TOL), as feed additives on the pharmacokinetic profile of FFC in rabbits. The disposition kinetics of FFC in rabbits were investigated after a single intravenous injection (25 mg/kg) in rabbits fed anticoccidial-free diets or feeds containing SUL (250 ppm), ROB (66 ppm), or TOL (2 ppm), respectively, for 20 days. Plasma FFC concentrations were determined by the high performance liquid chromatography (HPLC) method. The pharmacokinetic parameters of FFC were analyzed using a non-compartmental analysis based on the statistical moment theory. The results demonstrated that ROB feeding resulted in an obvious decrease in plasma FFC level as compared with anticoccidial-free feeding. The terminal elimination half-life (t1/2z), area under the concentration-time curve (AUC), area under the first moment curve (AUMC), and mean residence time (MRT) significantly decreased, whereas the elimination rate constant (λz) and total body clearance (CLz) obviously increased in rabbits pretreated with ROB. However, we did not find that SUL or TOL feeding had any effect on the pharmacokinetic profile of FFC. Our findings suggested that more attention should be paid to the use of FFC in rabbits supplemented with ROB.

[Fine mapping of mutant gene related corneal opacity mouse with SNPs].

To further investigate the genetic mechanism of the mutant mice(B6-Co) with hereditary corneal opacity phenotype obtained by ENU-induced mutagenesis from B6 in previous study, SNP markers were used to map the mutant gene of B6-Co mice. F2 generation mice were bred by backcrossing (B6-CoPxD2 )F1 with D2 and the DNA samples of F2 mutant mice were extracted from the tails. Five SNP sites that showed differences between B6 and D2 strains nearby the located region on chromosome 13 were screened from MGI database. Five SNPs, PCR-RFLP and linkage analyses were carried out to map the mutant gene. The result showed that the mutant gene was located between 112 546 283~113 397 654 bp on chromosome 13. There are five identified genes including Map3k1 that is associated with eye morphogenesis and eyelid closure of mouse in this region. This suggests that Map3k1 is the most probable candidate mutant gene of B6-Co mice.

[Transplantation of human glioma stem cells in nude mice with green fluorescent protein expression].

OBJECTIVES: To investigate the possibility of transplantation of human glioma stem cells (HGSCs) in nude mice stably expressing green fluorescent protein (GFP) so as to clearly identify the incubated HGSCs from the host tissues. METHODS: Transgenic C57BL/6J mice expressing GFP was crossed with nude mice of the line NC, then hairless male nude mice expressing GFP were crossed with hairy female pubescent mice to obtain nude mice with GFP expression the expression of GFP in the skin and organs of these nude mice were evaluated by naked eyes, and immunohistochemical and immunofluorescence assays. HGSCs were transplanted orthotopically into the caudate nuclei of nude mice expressing GFP. Immunohistochemistry was used to observe the transplanted tumor. RESULTS: The structures rich in adipose tissue of the 8th generation nude mice were dark green and the other organs were light green. However, green fluorescence was emitted from all tissues under fluorescence microscopy. Confocal fluorescence microscopy showed that the tumor cells were stained red, distinguished from the host cells distinctly in the brains bearing tumor transplanted orthotopically. CONCLUSION: Nude mice expressing GFP can be obtained by crossing the transgenic mice bearing naive immunity with nude mice. Orthotopic transplantation of HGSCs may be used in the investigation of tumor tissue reconstitution because of the easy identification between the transplantation tumor and host tissue.

Dynamic expression of rat heat shock protein gp96 and its gene during development of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is characterized by multicause, obvious multistage and multifocal processes of tumor progression. The development of HCC is related intimately to overexpression and signal transduction of many cellular factors. This study was undertaken to investigate the dynamic expression and alteration of heat shock protein (HSP) gp96 along with its gene during HCC development. METHODS: A rat model of hepatoma induced with 2-fluorenylacetamide (2-FAA, 0.05%) was established in male Sprague-Dawley rats. Total RNA and pathological changes were observed during hepatocarcinogenesis. Total RNAs were transcribed into cDNA by reverse transcription and the gene fragment of gp96 was amplified by nested RT-PCR. The gp96 expression in rat liver tissues was semi-quantitatively analyzed by immunohistochemistry. RESULTS: Histological examination suggested that hepatocytes in rats fed with 2-FAA showed vacuole-like denaturation at the early stages, then dysplastic nodules appeared at the middle stage, and finally progressed to tubercles of cancerous nests. A tendency of increasing liver gp96 protein level was found from normal liver to precancerous to cancerous tissues during hepatoma development (P<0.01), and was in accordance with the changes in gp96 mRNA (P<0.05). CONCLUSION: HSP gp96 is involved in HCC development and its overexpression may be a useful marker for early diagnosis.

Two kinds of ENU-induced scant hair mice and mapping of the mutant genes.

OBJECTIVE: To establish mouse models for human diseases through N-ethyl-N-nitrosourea (ENU) mutagenesis, and to provide groundwork to clone genes and study their functions after mapping the mutant genes. METHODS: 18 male D2 mice (G0) at age of 8-10 weeks old were injected intraperitoneally with ENU (100 mg/kg) once a week for three consecutive weeks. The treated male mice were mated with females of the same strain, and their offspring (G1) were used to screen for dominant and recessive mutation. After breeding the mutant F2 (D2B6 F1 intercrossing) mice, 39 microsatellites that are equally distributed on the mouse genome and are different between B6 and D2 strains were used to scan the genome. According to the log odds score (LODS) we determined whether these microsatellites were linked to the mutant genes and calculated the location of mutant genes based on their recombination ratio. RESULTS: We screened 532 G1 mice, of which 14 exhibited mutation phenotypes. None was dominantly hereditable. Two cases of recessive inheritable scant hair mice were obtained through testing 30 G1 mice with normal phenotype and potential recessive mutant genes. All showed scant coat hair, grew slowly, and hyperkeratoses of epidermis and bollicular horn plug in histological sections. Their visceral organs were not markedly different from normal, and they were named scant hair 1 Baojin (symbol is snthr(-1Bao)) and scant hair 2 Baojin (symbol is snthr(-2Bao)). Through microsatellite screening we found that the LODS between snthr(-1Bao) and D9Mit243 was 7.73, and the linkage was determined. After analyzing the recombination ratio between snthr(-1Bao) and microsatellite D9Mit18 which was near snthr(-1Bao) based on a total number of 126 F2 mice with the scant hair phenotype, we determined that snthr(-1Bao) was located at chromosome 9 and was 71cM from centromere. Using the same technique, snthr(-2Bao) was mapped to the same position as snthr(-1Bao). CONCLUSION: In our research, two cases of scant hair mice provide good models for the study of dermatology, and the location of mutant genes provides a solid foundation for cloning new mice scant hair genes.

Identification of QTLs for weight and cross-sectional area on cervical enlargement of spinal cord in mice.

Two inbred strains of mice, A/J, C57BL/6J and F2 intercross progenies,were used for QTL mapping for weight and cross-sectional area on cervical enlargement of spinal cord in mice. 13 QTLs located on Chromosome 2, 4, 8, 14, 15, 17, 18, 19 and X, respectively, for these two traits were found. Six QTLs were responsible for the cord weight, four for the cross-sectional area and three for both. Among 13 QTLs, three QTLs (P < 0.01) termed SC1 (located near D15Mit158) ,SC2 (DXMit140) and SC3 (DXMit64) accounted for 24%, 19% and 15% of the total variance in weight phenotype, and -3.78, 3.41 and 2.06 mg additive effect, respectively. The P value of other QTLs is between 0.01 and 0.05. SC1 is only one QTL that responsible for both weight and cross-sectional area in three QTLs above. This study revealed the location of major QTLs related size of spinal cord in mice, and may be helpful in fine mapping and ultimate identification of candidate genes.