Advances in epigenetic regulation of Chinese hamster ovary cells / 生物工程学报

Chinese hamster ovary (CHO) cells play an irreplaceable role in biopharmaceuticals because the cells can be adapted to grow in suspension cultures and are capable of producing high quality biologics exhibiting human-like post-translational modifications. However, gene expression regulation such as transgene silencing and epigenetic modifications may reduce the recombinant protein production due to the decrease of expression stability of CHO cells. This paper summarized the role of epigenetic modifications in CHO cells, including DNA methylation, histone modification and miRNA, as well as their effects on gene expression regulation.

IL-33 gene recombination and expression does not affect the phenotypic characteristics of rabies virus in vitro / 细胞与分子免疫学杂志

Objective To create a recombinant rabies virus overexpressing IL-33 and to clarify the effect of IL-33 overexpression on the phenotypic characteristics of recombinant virus in vitro. Methods The IL-33 gene was obtained and amplified from the brain of a highly virulent strain of rabies infected mouse. It was then inserted between the G and L genes of the parental virus LBNSE genome by reversing genetic manipulation and rescuing a recombinant virus overexpressing IL-33. BSR cells or mouse NA cells were infected with recombinant rabies virus (rLBNSE-IL33) and the parental strain LBNSE. Sequencing and fluorescent antibody virus neutralization assay was employed to detect the stability of recombinant virus at multiplicity of infection=0.01. Viral titres focal forming units (FFU) were detected to plot multi-step growth curves (multiplicity of infection=0.01). Cytotoxicity assay kit was used to detect cellular activity. ELISA was adopted to identify the IL-33 in the supernatant of infected cells of different multiplicity of infection. Results Rescued rLBNSE-IL33 overexpressing IL-33 remained stable for at least 10 consecutive generations and had virus titers of approximately 108 FFU/mL. rLBNSE-IL33 was able to express IL-33 at high levels in a dose-dependent manner, but no high expression of IL-33 was detected in the supernatant of cells infected by LBNSE. Examination of the titers of rLBNSE-IL33 and the parental strain LBNSE in BSR and NA cells over 5 days showed no significant differences and similar kinetic properties in growth. Overexpression of IL-33 had no significant effect on the proliferation and activity of infected cells. Conclusion Overexpression of IL-33 does not significantly affect the phenotypic characteristics of recombinant rabies virus in vitro.

Mitochondrial energy metabolism in baby hamster kidney (BHK-21/C13) cells treated with karnozin extra® / Metabolismo energético mitocondrial en células de riñón de hámster bebé (BHK-21 / C13) tratadas con karnozin extra®

SUMMARY: Carnosine is known as a natural dipeptide, which inhibits the proliferation of tumor cells throughout its action on mitochondrial respiration and cell glycolysis. However, not much is known about its effects on the metabolism of healthy cells. We explored the effects of Karnozin EXTRA® capsule with different concentrations of L-carnosine, on the cell viability and the expressions of intermediate filament vimentin (VIM) and superoxide dismutase (SOD2) in normal fibroblasts BHK-21/C13. Furthermore, we investigated its action on the energy production of these cells. Cell viability was quantified by the MTT assay. The Clark oxygen electrode (Oxygraph, Hansatech Instruments, England) was used to measure the "intact cell respiration rate", state 3 of ADP-stimulated oxidation, maximum oxidation capacity and the activities of complexes I, II and IV. Results showed that Karnozin EXTRA® capsule in concentrations of 2 and 5 mM of L-carnosine did not induce toxic effects and morphological changes in treated cells. Our data revealed a dose-dependent immunofluorescent signal amplification of VIM and SOD2 in the BHK-21/C13 cell line. This supplement substantially increased the recorded mitochondrial respiration rates in the examined cell line. Due to the stimulation of mitochondrial energy production in normal fibroblasts, our results suggested that Karnozin EXTRA® is a potentially protective dietary supplement in the prevention of diseases with altered mitochondrial function.

RESUMEN: La carnosina se conoce como dipéptido natural, que inhibe la proliferación de células tumorales a través de su acción sobre la respiración mitocondrial y la glucólisis celular. Sin embargo, no se sabe mucho de sus efectos sobre el metabolismo de las células sanas. Exploramos los efectos de la cápsula Karnozin EXTRA® con diferentes concentraciones de L-carnosina, sobre la viabilidad celular y las expresiones de vimentina de filamento intermedio (VIM) y superóxido dismutasa (SOD2) en fibroblastos normales BHK-21 / C13. Además, estudiamos su acción sobre la producción de energía de estas células. La viabilidad celular se cuantificó mediante el ensayo MTT. Se utilizó el electrodo de oxígeno Clark (Oxygraph, Hansatech Instruments, Inglaterra) para medir la "tasa de respiración de células intactas", el estado 3 de oxidación estimulada por ADP, la capacidad máxima de oxidación y las actividades de los complejos I, II y IV. Los resultados mostraron que la cápsula de Karnozin EXTRA® en concentraciones de 2 y 5 mM de L- carnosina no indujo efectos tóxicos ni cambios morfológicos en las células tratadas. Nuestros datos revelaron una amplificación de señal inmunofluorescente dependiente de la dosis de VIM y SOD2 en la línea celular BHK-21 / C13. Este suplemento aumentó sustancialmente las tasas de respiración mitocondrial registradas en la línea celular examinada. Debido a la estimulación de la producción de energía mitocondrial en fibroblastos normales, nuestros resultados sugirieron que Karnozin EXTRA® es un suplemento dietético potencialmente protector en la prevención de enfermedades con función mitocondrial alterada.

Knockout of caspase-7 gene improves the expression of recombinant protein in CHO cell line through the cell cycle arrest in G2/M phase

BACKGROUND: Chinese hamster ovary cell line has been used routinely as a bioproduction factory of numerous biopharmaceuticals. So far, various engineering strategies have been recruited to improve the production efficiency of this cell line such as apoptosis engineering. Previously, it is reported that the caspase-7 deficiency in CHO cells reduces the cell proliferation rate. But the effect of this reduction on the CHO cell productivity remained unclear. Hence, in the study at hand the effect of caspase-7 deficiency was assessed on the cell growth, viability and protein expression. In addition, the enzymatic activity of caspase-3 was investigated in the absence of caspase-7. RESULTS: Findings showed that in the absence of caspase-7, both cell growth and cell viability were decreased. Cell cycle analysis illustrated that the CHO knockout (CHO-KO) cells experienced a cell cycle arrest in G2/M phase. This cell cycle arrest resulted in a 1.7-fold increase in the expression of luciferase in CHO-KO cells compared to parenteral cells. Furthermore, in the apoptotic situation the enzymatic activity of caspase-3 in CHO-KO cells was approximately 3 times more than CHO-K1 cells. CONCLUSIONS: These findings represented that; however, caspase-7 deficiency reduces the cell proliferation rate but the resulted cell cycle arrest leads to the enhancement of recombinant protein expression. Moreover, increasing in the caspase-3 enzymatic activity compensates the absence of caspase-7 in the caspase cascade of apoptosis.

Immunogenicity and influencing factors of hepatitis B vaccination based on different vaccination schedules among chronic kidney disease patients / 中华流行病学杂志

Objective: To explore the immunogenicity and influencing factors of hepatitis B vaccination based on different vaccination schedules among chronic kidney disease (CKD) patients. Methods: CKD patients who participated in randomized controlled trials in four hospitals in Shanxi province and completed three doses of 20 µg vaccination (at months 0, 1 and 6) and four doses of 20 µg or 60 µg vaccination (at months 0, 1, 2, and 6) were surveyed from May 2019 to July 2020.According to the ratio of 1∶1∶1, 273 CKD patients were divided into 3 groups randomly. Quantification of the anti-hepatitis B surface antigen-antibody (anti-HBs) in serum samples was performed using chemiluminescent microparticle immunoassay at months 1 and 6 after the entire course of the vaccinations. The positive rate, high-level positive rate, geometric mean concentration (GMC) of anti-HBs, and the influencing factors were analyzed by χ2 tests, analysis of variance, unconditional logistic regression analysis. Results: A total of 273 CKD patitents were participants.The positive rates in the CKD patients with four doses of 20 µg vaccination (92.96%,66/71) or 60 µg vaccination (93.15%, 68/73) were higher than that in the CKD patients with three doses of 20 µg vaccination (81.69%, 58/71) at month one after the full course of the vaccinations (P<0.05). The GMCs of anti-HBs showed similar results (2 091.11 mIU/ml and 2 441.50 mIU/ml vs. 1 675.21 mIU/ml) (P<0.05). The positive rate was higher in the CKD patients with four doses of 60 µg vaccination (94.83%,55/58) than in those with three doses of 20 µg vaccination (78.79%,52/66) (P<0.05) at month six after the full course of the vaccinations. And the GMC of anti-HBs in the patients with four doses of 60 µg vaccination (824.28 mIU/ml) was significantly higher than those in the patients with 3 or 4 doses of 20 µg vaccination (639.74 mIU/ml and 755.53 mIU/ml) (P<0.05). After controlling the confounding factors, the positive rate in the CKD patients with four doses of 60 µg vaccination were 3.19 (95%CI: 1.02-9.96) and 5.32 (95%CI: 1.27-22.19) times higher than those in the patients with three doses of 20 µg vaccination at months 1 and 6 after the full course of the vaccinations, respectively. The positive rate in CKD patients without immune suppression or hormone therapy was 3.33 (95%CI: 1.26-8.80) and 4.78 (95%CI: 1.47-15.57) times higher than those in the patients with such therapy, respectively. Conclusions: Four doses of 20 µg or 60 µg hepatitis B vaccination could improve the immunogenicity in patients with CKD. And four doses of 60 µg vaccination might play a positive role in maintaining anti-HBs in this population. The immunogenicity in the CKD patients with immune suppression or hormone therapy was poor.

A comprehensive morphometric study of visceral and subcutaneous adipose tissue depots in mice, hamsters and rats / Un estudio morfométrico completo de los depósitos de tejido adiposo visceral y subcutáneo en ratones, hámsters y ratas

SUMMARY: Adipose tissue morphology of different fat tissue depots can be described using the number of adipocytes and cell surface of adipocytes. This study deals with characteristics and morphometric analysis of white and brown adipose tissue depots in healthy adult laboratory mice, hamsters and rats of both sexes. The number of unilocular adipocytes in white adipose tissue differs from one adipose tissue depot to another, with the largest number of adipocytes in mice and a similar number in hamsters and rats. The smallest surface area and the largest percentage of small unilocular adipocytes were found in mice. White adipose tissue in hamsters and rats was predominantly made out of a larger percentage of medium-sized adipocytes and a smaller percentage of small and medium-sized adipocytes. Uncoupling protein 1 positive multilocular adipocytes were found in classic brown adipose tissue depots with larger percentages in mice (93.20 %) and hamsters (91.30 %), while rats had a smaller percentage (78.10 %). In white and brown adipose tissue, significant differences between species and both sexes within the same species were found, indicating the influence of sexual dimorphism. The presented morphometric results could serve as a basis for further studies concerning experimental animal models of metabolic disorders and obesity.

RESUMEN: La morfología del tejido adiposo de diferentes depósitos de tejido graso se puede describir utilizando el número de adipocitos y la superficie celular de los adipocitos. Este estudio analiza las características y el análisis morfométrico de los depósitos de tejido adiposo blanco y marrón en ratones, hamsters y ratas de laboratorio, adultos sanos de ambos sexos. El número de adipocitos uniloculares en el tejido adiposo blanco difiere de un depósito de tejido adiposo a otro, con el mayor número de adipocitos en ratones y un número similar en hámsteres y ratas. La superficie más pequeña y el mayor porcentaje de adipocitos uniloculares pequeños se encontraron en ratones. El tejido adiposo blanco en hámsteres y ratas estaba compuesto predominantemente por un mayor porcentaje de adipocitos de tamaño mediano y un porcentaje menor de adipocitos de tamaño pequeño y mediano. Los adipocitos multiloculares positivos para la proteína desacopladora 1 se encontraron en depósitos de tejido adiposo marrón clásico con mayores porcentajes en ratones (93,20 %) y hámsters (91,30 %), mientras que las ratas tenían un porcentaje menor (78,10 %). En el tejido adiposo blanco y pardo se encontraron diferencias significativas entre especies y entre ambos sexos dentro de una misma especie, lo que indica la influencia del dimorfismo sexual. Los resultados morfométricos presentados podrían servir como base para futuros estudios sobre modelos animales experimentales de trastornos metabólicos y obesidad.

Identification and sequence analysis of prolactin receptor and its differential expression profile at various developmental stages in striped hamsters

Prolactin (PRL) plays critical roles in regulation of biological functions with the binding of specific prolactin receptor (PRLR). Revealing the expression patterns of PRLR at different developmental stages is beneficial to better understand the role of PRL and its mechanism of action in striped hamsters. In this study, the cDNA sequence of PRLR (2866-base-pairs) was harvested from the pituitary of mature female striped hamsters (Cricetulus barabensis) that contains an 834-base-pair 5′-untranslated region (1-834 bp), a 1848-base-pair open reading frame (835-2682 bp), and a 184-base-pair 3′-untranslated region (2683-2866). The 1848-base-pair open reading frame encodes a mature prolactin-binding protein of 592 amino acids. In the mature PRLR, two prolactin-binding motifs, 12 cysteines, and five potential Asn-linked glycosylation sites were detected. Our results showed that the PRLR mRNA quantity in the hypothalamus, pituitary, ovaries, or testis was developmental-stage-dependent, with the highest level at sub-adult stage and the lowest level at old stage. We also found that PRLR mRNAs were highest in pituitary, medium level in hypothalamus, and lowest in ovaries or testis. PRLR mRNAs were significantly higher in males than in females, except in the hypothalamus and pituitary from 7-week-old striped hamsters. Moreover, the PRLR mRNAs in the hypothalamus, pituitary, and ovaries or testis were positively correlated with the expression levels of GnRH in the hypothalamus. These results indicated that the PRLR has conserved domain in striped hamster, but also possesses specific character. PRLR has multiple biological functions including positively regulating reproduction in the striped hamster.

Impact of metabolic enzymes overexpression on transient expression of anti-hLAG3 by CHO cells / 生物工程学报

To enhance recombinant protein production by CHO cells, We compared the impact of overexpression of metabolic enzymes, namely pyruvate carboxylase 2 (PYC2), malate dehydrogenase Ⅱ (MDH2), alanine aminotransferase Ⅰ (ALT1), ornithine transcarbamylase (OTC), carbamoyl phosphate synthetase Ⅰ (CPSⅠ), and metabolism related proteins, namely taurine transporter (TAUT) and Vitreoscilla hemoglobin (VHb), on transient expression of anti-hLAG3 by ExpiCHO-S. Overexpression of these 7 proteins could differentially enhance antibody production. OTC, CPSI, MDH2, and PYC2 overexpression could improve antibody titer by 29.2%, 27.6%, 24.1%, and 20.3%, respectively. Specifically, OTC and MDH2 could obviously improve early-stage antibody production rate and the culture period was shortened by 4 days compared with that of the control. In addition, OTC and MDH2 had little impact on the affinity of anti-hLAG3. In most cases, overexpression of these proteins had little impact on the cell growth of ExpiCHO-S. MDH2 and ALT1 overexpression in H293T cells could also improve antibody production. Overall, overexpression of enzymes involved in cellular metabolism is an effective tool to improve antibody production in transient expression system.

Efficacy and mechanism of new resource medicinal materia Moringa oleifera leaves against hyperlipidemia / 中国中药杂志

High fat diet induced hyperlipidemia hamster model was used to explore the anti-hyperlipidemia effect of water extract of Moringa oleifera leaves( WEMOL). On this basis,the possible action mechanism was predicted by network pharmacology. Golden hamsters were randomly divided into normal diet group( NFD),high-fat diet group( HFD),simvastatin group,high dose group of WEMOL( HIWEMOL) and low dose group of WEMOL( LOWEMOL). The model was administered simultaneously for 66 days,during which the body weight changes of hamsters were recorded. At the end of the experiment,serum lipid level and serum transaminase level of golden hamsters in each group were detected,and the pathological changes of liver were observed by hematoxylin-eosin( HE) staining. The results showed that WEMOL could significantly decrease the serum total cholesterol( TC),total triglyceride( TG),low density lipoprotein cholesterol( LDL-c) levels,and reduce the lipid deposition in liver tissue,thus improving the hyperlipidemia of golden hamsters. According to the prediction of network pharmacology,219 targets of potential active components of M.oleifera leaves and 185 targets of water-soluble potential active components of M. oleifera leaves for the treatment of hyperlipidemia were obtained separately. The MCODE analysis was performed on the PPI network of 219 targets and 185 targets obtained above and got five and four clusters respectively. The signaling pathway analysis of clusters showed that among the common pathways,nonalcoholic fatty liver,insulin resistance,MAPK signaling pathway,estrogen signaling pathway,cell apoptosis and HIF-1 signaling pathway were associated with hyperlipidemia. In addition,the potential active components of M. oleifera leaves could also inhibit the metabolic inflammation of hyperlipidemia by modulating complement and coagulation cascades signaling pathway,and GSK3 B,F2,AKT1,RELA,SERPINE1 might be the key targets. The water-soluble potential active components of M. oliefera leaves could modulate lipid metabolism by modulating AMPK signaling pathway and JAK-STAT signaling pathway,with PIK3 CB,PIK3 CA,CASP3,AKT1 and BCL2 as the key targets. These results suggested that WEMOL had anti hyperlipidemia effect,and its mechanism might be related to the protein expression regulation of lipid metabolism,nonalcoholic fatty liver disease and atherosclerosis related signaling pathways.

Arsenic Trioxide Combining Leflunomide Activates Nrf2-ARE-HO-1 Signaling Pathway and Protects Heart Xenografts / 中国结合医学杂志

OBJECTIVE@#To investigate the molecular mechanisms underlying the effects of arsenic trioxide (As@*METHODS@#Transplantation of LVG hamster hearts to Lewis rats was performed by anastomosis of vessels in the neck using end-to-end anastomosis with a non-suture cuff technique. Four groups of recipient rats (n=6 in each) were treated with normal saline (control), As@*RESULTS@#Expression of Nrf2-ARE-HO-1 signaling pathway was upregulated in heart xenografts in rats treated with As@*CONCLUSION@#Combination treatment with As

Analysis of the Electrophoretic Profiles of Prion Protein in Carcinous and Pericarcinous Lysates of Six Different Types of Cancers / 生物医学与环境科学（英文）

Objective@#To find the different electrophoretic profiles of prion protein in carcinous and individual pericarcinous tissues in lysates of gastric, colon, liver, lung, thyroid, and laryngeal cancers.@*Methods@#Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot were used to test the amounts and electrophoretic patterns of total PrP and the tolerance of PK (protease K) digestion among six various cancer tissue types.@*Results@#A mass of PrP signals with a large molecular weight were identified in the homogenates of peripheral tissues. The amounts and electrophoretic patterns of total PrP did not differ significantly between carcinous and pericarcinous tissues. PrPs in all types of the tested cancer samples were PK sensitive but showed diversity in the tolerance of PK digestion among various tissue types.@*Conclusions@#The study revealed that the included electrophoretic patterns of carcinous and pericarcinous tissues were almost similar. Unlike PrP-specific immunohistochemical assay, evaluation of PrP electrophoretic patterns in the peripheral organs and tissues by Western blot does not reflect tumor malignancy.

Effect of topical 2% eucalyptus extract on 5-fu-induced oral mucositis in male golden hamsters

Abstract Oral mucositis is a common inflammatory complication among patients with cancer. This study evaluated the histopathological, stereological, and antioxidant markers of 2% eucalyptus extract in induced oral mucositis in male golden hamsters. In this animal study, oral mucositis was induced in 30 male golden hamsters by 5-FU (60 mg/kg) on days 0, 5, and 10 of the study. The cheek pouch was scratched with a sterile needle once daily on days 3 and 4. On days 14-17, 2% eucalyptus hydroalcoholic extract gel and Calendula officinalis extract gel groups were treated and then compared with a non-treated control group. The histopathological and stereological scores and the pouch content of malondialdehyde, as well as the activities of glutathione and myeloperoxidase in the pouch tissue, were evaluated. Histopathologic scores of oral mucositis were lower in the eucalyptus gel group than those of the calendula and control groups (p<0.05). Also, a lower malondialdehyde level and higher myeloperoxidase and glutathione activities were detected in the eucalyptus group in comparison to the calendula and control groups (p<0.001). The thickness of the mucosa and submucosa increased in the eucalyptus group. The numerical density of the fibroblast and the volume density of the collagen significantly increased in the eucalyptus group. In conclusion, the use of eucalyptus hydroalcoholic extract may be associated with reduced intensity of oral mucositis, diminished concentration of malondialdehyde, increased activity of myeloperoxidase and glutathione, increased volume of mucosa and submucosa, increased fibroblast and collagen in the induced oral mucositis in golden hamsters undergoing 5-FU consumption.

Resumo A mucosite oral é uma complicação inflamatória comum em pacientes com câncer. Este estudo avaliou os marcadores histopatológicos, estereológicos e antioxidantes de Eucalyptus 2% na mucosite oral induzida em hamsters dourados machos. Neste estudo em animais, a mucosite oral foi induzida em 30 hamsters golden masculinos por 5-FU (60 mg / kg) nos dias 0, 5 e 10 do estudo. A bolsa da bochecha foi arranhada com uma agulha estéril uma vez ao dia nos dias 3 e 4. Nos dias 14 a 17, os grupos de gel de eucalipto a 2% e curativos à base de gel foram tratados e comparados com um grupo controle. Foram avaliados os escores histopatológicos e estereológicos e o conteúdo de malondialdeído na bolsa, bem como as atividades de glutationa e mieloperoxidase no tecido da bolsa. Os escores histopatológicos de mucosite foram menores no grupo de gel de eucalipto a 2% do que os do gel e do grupo controle (p <0,05). Além disso, um nível mais baixo de malondialdeído e maiores atividades de mieloperoxidase e glutationa foram detectadas no grupo tratado com eucalipto em comparação aos grupos à base de gel e controle (p <0,001). A espessura da mucosa e submucosa aumentou no grupo Eucalyptus. A densidade numérica do fibroblasto e a densidade do volume do colágeno aumentaram significativamente nos grupos tratados com eucalipto. Em conclusão, o uso do extrato hidroalcoólico de Eucalyptus pode estar associado a menor intensidade de mucosite oral, diminuição da concentração de malondialdeído, aumento da atividade de mieloperoxidase e glutationa, aumento do volume de mucosa e submucosa, aumento de fibroblastos e colágeno na mucosite oral induzida em hamsters dourados em consumo de 5 UF.

Oxyurid nematodes of pet rodents in Slovakia - a neglected zoonotic threat / Nematódeos oxiurídeos de roedores de estimação na Eslováquia - uma ameaça zoonótica negligenciada

Abstract The role of rodents as reservoirs of helminths of public health importance is not well known. The zoonotic potential of Syphacia spp. has been confirmed; therefore, the study aimed to estimate the occurrence of oxyurid nematodes in small rodents from pet shops and breeding clubs in Slovakia. Fecal samples of 586 pet rodents kept in 133 cages were collected between 2016 and 2018 and examined by Faust´s flotation method. Four species of oxyurid nematodes, Syphacia muris, S. obvelata, Aspiculuris tetraptera and Paraspidodera uncinata were detected. A. tetraptera was found in the faecal samples of all rodent species included in this survey. The number of positive boxes varied from 5.4% in hamsters to 70.0% with mice. The prevalence of Syphacia muris was highest in Mongolian gerbils where up to 75.0% boxes were positive; S. obvelata was found in 26.7% of boxes with mice, 25.0% of boxes with Mongolian gerbils and 3.2% of boxes with rats. The high prevalence of Syphacia spp. in all animal species points out the infection risk for humans. Animals offered for sale are often in close contact with human beings; therefore they should be regularly tested for parasites and then effectively dewormed.

Resumo O papel dos roedores como reservatórios de helmintos de importância para a saúde pública não é bem conhecido. O potencial zoonótico de Syphacia spp. foi confirmado; portanto, o estudo teve como objetivo estimar a ocorrência de nematóides oxiurídeos em pequenos roedores de pet shops e clubes de reprodução na Eslováquia. Amostras fecais de 586 roedores mantidos em 133 gaiolas foram coletadas entre 2016 e 2018 e examinadas pelo método de flotação de Faust. Foram detectadas quatro espécies de nematódeos oxiurídeos, Syphacia muris, S. obvelata, Aspiculuris tetraptera e Paraspidodera uncinata, A. tetraptera foi encontrado nas amostras fecais de todas as espécies de roedores incluídas nesta pesquisa. O número de gaiolas positivas variou de 5,4% em hamsters a 70,0% em camundongos. A prevalência de Syphacia muris foi maior nos gerbilos da Mongólia, onde até 75,0% das gaiolas foram positivas; S. obvelata foi encontrada em 26,7% das gaiolas com camundongos, 25,0% das gaiolas com gerbilos da Mongólia e 3,2% das gaiolas com ratos. A alta prevalência de Syphacia spp. em todas as espécies animais aponta o risco de infecção para os seres humanos. Animais oferecidos para venda estão frequentemente em contato próximo com seres humanos; portanto, eles devem ser regularmente testados quanto a parasitas e, então, efetivamente desparasitados.

Investigating associations between intestinal alterations and parasite load according to Bifidobacterium spp. and Lactobacillus spp. abundance in the gut microbiota of hamsters infected by Leishmania infantum

BACKGROUND Visceral leishmaniasis (VL) is a tropical neglected disease with high associated rates of mortality. Several studies have highlighted the importance of the intestinal tract (IT) and gut microbiota (GM) in the host immunological defense. Data in the literature on parasite life cycle and host immune defense against VL are scarce regarding the effects of infection on the IT and GM. OBJECTIVES This study aimed to investigate changes observed in the colon of Leishmania infantum-infected hamsters, including alterations in the enteric nervous system (ENS) and GM (specifically, levels of bifidobacteria and lactobacilli). METHODS Male hamsters were inoculated with L. infantum and euthanised at four or eight months post-infection. Intestines were processed for histological analysis and GM analysis. Quantitative polymerase chain reaction (qPCR) was performed to quantify each group of bacteria: Bifidobacterium spp. (Bf) and Lactobacillus spp (LacB). FINDINGS Infected hamsters showed histoarchitectural loss in the colon wall, with increased thickness in the submucosa and the mucosa layer, as well as greater numbers of intraepithelial lymphocytes. Forms suggestive of amastigotes were seen inside mononuclear cells. L. infantum infection induced changes in ENS, as evidenced by increases in the area of colonic enteric ganglia. Despite the absence of changes in the levels of Bf and LacB during the course of infection, the relative abundance of these bacteria was associated with parasite load and histological alterations. MAIN CONCLUSIONS Our results indicate that L. infantum infection leads to important changes in the colon and suggest that bacteria in the GM play a protective role.

Numerical simulation and optimization of impeller combination used in stirred bioreactor / 生物工程学报

Bioreactors have been central in monoclonal antibodies and vaccines manufacturing by mammalian cells in suspension culture. Numerical simulation of five impeller combinations in a stirred bioreactor was conducted, and characteristics of velocity vectors, distributions of gas hold-up, distributions of shear rate in the bioreactor using 5 impeller combinations were numerically elucidated. In addition, genetically engineered CHO cells were cultivated in bioreactor installed with 5 different impeller combinations in fed-batch culture mode. The cell growth and antibody level were directly related to the maximum shear rate in the bioreactor, and the highest viable cell density and the peak antibody level were achieved in FBMI3 impeller combination, indicating that CHO cells are sensitive to shear force produced by impeller movement when cells were cultivated in bioreactor at large scale, and the maximum shear rate would play key roles in scaling-up of bioreactor at industrial scale.

Effects of different signal peptides on the secretion of human-mouse chimeric CMV-IgM / 生物工程学报

In order to prepare human-mouse chimeric cytomegalovirus-immunoglobulin M (CMV-IgM) in vitro and study the effects of different signal peptides on the secretion of CMV-IgM, genes were amplified from hybridoma cell line using RLM-RACE to construct the expression vector of chimeric CMV-IgM. Then, the signal peptide of SigF itself was replaced by five different secreted signal peptides (SigA-SigE) by PCR method, and the CHO cell was chosen as host cell for in vitro expression. SDS-PAGE, SEC-HPLC and ELISA experiments were carried out to evaluate the protein expression level and immunoreactivity of the purified CMV-IgM. A 910 kDa recombinant protein was successfully prepared and signal peptides (SigA-SigE) had an increased expressed CMV-IgM, which were 6.72, 5.19, 1.44, 1.85 and 1.98 times higher than that of the CMV 6# cell signal peptide SigF. In summary, this work provides a theoretical basis for the development of human-mouse chimeric CMV-IgM, and a novel route to increase the expression level of CMV-IgM.

Caspase-7 deficiency in Chinese hamster ovary cells reduces cell proliferation and viability

BACKGROUND: Chinese hamster ovary (CHO) cells are the most commonly used mammalian host cell In the commercial-scale production of biopharmaceutical proteins. Modification of genes involved in apoptosis may improve the productivity of CHO cells. Executive caspases, including caspases 3 and 7, play critical roles in apoptosis. The effects of the ablation of the caspase 7 gene on proliferation and viability of CHO cells remains unknown. In this study, we applied clustered regularly interspaced short palindromic repeat (CRISPR/Cas9) to target caspase 7 gene of CHO K1 cell via all in one and homology targeted integration strategies. Consequently, the effect of caspase 7 deficiency on cell proliferation, viability, and apoptosis was studied by MTT assay and flow cytometry. RESULTS: Findings of gel electrophoresis, western blotting, and sequencing confirmed the caspase 7 gene silencing in CHO cells (CHO-KO). Proliferation assay revealed that caspase 7 deficiency in CHO cells resulted in the reduction of proliferation in various CHO-KO clones. Besides, the disruption of caspase 7 had negative effects on cell viability in exposure with NaBu which confirmed by MTT assay. Results of flow cytometry using Anexin V/PI demonstrated that Nabu treatment (11 mM) declined the percentage of live CHO-K1 and CHO-KO cells to 70.3% and 5.79%. These results verified that the CHO-K1 cells were more resistant to apoptosis than CHO-KO, however most of CHO-KO cells undergone early apoptosis (91.9%) which seems to be a fascinating finding. CONCLUSION: These results reveal that caspase 7 may be involved in the cell cycle progression of CHO cells. Furthermore, it seems that targeting caspase 7 is not the ideal route as it had previously been imagined within the prevention of apoptosis but the relation between caspase 7 deficiency, cell cycle arrest, and the occurrence of early apoptosis will require more investigation.

DNA nanovaccines prepared using LemA antigen protect Golden Syrian hamsters against Leptospira lethal infection

BACKGROUND Nanoparticles (NPs) are viable candidates as carriers of exogenous materials into cells via transfection and can be used in the DNA vaccination strategy against leptospirosis. OBJECTIVES We evaluated the efficiency of halloysite clay nanotubes (HNTs) and amine-functionalised multi-walled carbon nanotubes (NH2-MWCNTs) in facilitating recombinant LemA antigen (rLemA) expression and protecting Golden Syrian hamsters (Mesocricetus auratus) against Leptospira interrogans lethal infection. METHODS An indirect immunofluorescent technique was used to investigate the potency of HNTs and NH2-MWCNTs in enhancing the transfection and expression efficiency of the DNA vaccine in Chinese hamster ovary (CHO) cells. Hamsters were immunised with two doses of vaccines HNT-pTARGET/lemA, NH2-MWCNTs-pTARGET/lemA, pTARGET/lemA, and empty pTARGET (control), and the efficacy was determined in terms of humoral immune response and protection against a lethal challenge. FINDINGS rLemA DNA vaccines carried by NPs were able to transfect CHO cells effectively, inducing IgG immune response in hamsters (p < 0.05), and did not exhibit cytotoxic effects. Furthermore, 83.3% of the hamsters immunised with NH2-MWCNTs-pTARGET/lemA were protected against the lethal challenge (p < 0.01), and 66.7% of hamsters immunised with HNT-pTARGET/lemA survived (p < 0.05). MAIN CONCLUSIONS NH2-MWCNTs and HNTs can act as antigen carriers for mammalian cells and are suitable for DNA nanovaccine delivery.

Comparative assessment of the replication efficiency of dengue, yellow fever, and chikungunya arboviruses in some insect and mammalian cell lines

Abstract INTRODUCTION: Insect cell cultures play an essential role in understanding arboviral replication. However, the replicative efficiency of some of these viruses such as dengue (DENV), yellow fever (YFV), and chikungunya (CHIKV) in a new cellular substrate (Lulo) and in the other two recognized cell lines has not been comparatively assessed. METHODS: Vero, C6/36, and Lulo cell lines were infected with DENV, YFV, and CHIKV. The viral progeny was quantified through plaque assays and quantitative reverse transcription-polymerase chain reaction, while for DENV2, the findings were confirmed by immunofluorescence antibody assay. RESULTS: The higher DENV2 titer (from multiplicity of infection 0.001) was obtained on day four post-infection in C6/36 and on day six in Vero cells, while the Lulo cell line was almost impossible to infect under the same conditions. However, C6/36 showed the highest values of viral RNA production compared to Vero cells, while the quantification of the viral RNA in Lulo cells showed high levels of viral genomes, which had no correlation to the infectious viral particles. CONCLUSIONS: C6/36 was the most efficient cell line in the alpha and flavivirus production, followed by Vero cells. Thus, Lulo cells may be a useful substrate to study the mechanisms by which cells evade viral replication.

Red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells / Própolis vermelha e L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256

ABSTRACT Objective: To evaluate the effect of red propolis and L-lysine on angiogenesis and tumor growth in a new model of hamster cheek pouch inoculated with Walker 256 tumor cells. Methods: The study consisted of two experiments with four groups each (total: 57 hamsters). In the experiment 1, the animals were inoculated with Walker tumor cells, followed by administration of test substances (red propolis 200mg/5mL/kg or L-lysine 150mg/kg) or control substances (gum arabic 5mL/kg or water 5mL/kg) for 10 days. The animals in the experiment 2 received red propolis, L-lysine, gum arabic or water at the same doses, for 33 days prior to inoculation of Walker tumor cells, followed by 10 days of treatment with the same substances. Based on single-plane images, angiogenesis was quantified (mean vascular area), in percentage, and tumor area (mm2) and perimeter (mm). Results: In the experiment 1, compared to animals receiving water, the mean vascular area expressed in percentage was significantly smaller in animal treated with propolis (p<0.05) and L-lysine (p<0.001). Conclusion: Both red propolis and L-lysine inhibited tumor angiogenesis in the new hamster cheek pouch model when administered after tumor inoculation.

RESUMO Objetivo: Avaliar o efeito da própolis vermelha e da L-lisina na angiogênese e no crescimento tumoral em novo modelo de bolsa jugal de hamster inoculada com células de tumor de Walker 256. Métodos: O estudo consistiu em dois experimentos com quatro grupos cada (total: 57 hamsters). No experimento 1, os animais foram inoculados com células de tumor de Walker, tendo em seguida administradas as substâncias teste (própolis vermelha 200mg/5mL/kg ou L-lisina 150mg/kg) ou controle (goma arábica 5mL/kg ou água 5mL/kg) por 10 dias. Os animais do experimento 2 receberam própolis vermelha, L-lisina, goma arábica ou água nas mesmas doses, por 33 dias antes do inóculo das células de tumor de Walker, seguido por 10 dias de tratamento com as mesmas substâncias. Baseado em imagens em plano único, foram quantificados a angiogênese (área vascular média), em termos percentuais, e a área (mm2) e o perímetro (mm) do tumor. Resultados: Comparada aos animais que receberam água, a área vascular média, expressa em percentagem, foi significativamente menor nos animais tratados com própolis (p<0,05) e com L-lisina (p<0,001). Conclusão: Tanto a própolis vermelha quanto a L-lisina inibiram a angiogênese no novo modelo de bolsa jugal de hamsters, quando administradas após a inoculação do tumor.