Enhanced crystalline cellulose degradation by a novel metagenome-derived cellulase enzyme

Metagenomics has revolutionized access to genomic information of microorganisms inhabiting the gut of herbivorous animals, circumventing the need for their isolation and cultivation. Exploring these microorganisms for novel hydrolytic enzymes becomes unattainable without utilizing metagenome sequencing. In this study, we harnessed a suite of bioinformatic analyses to discover a novel cellulase-degrading enzyme from the camel rumen metagenome. Among the protein-coding sequences containing cellulase-encoding domains, we identified and subsequently cloned and purified a promising candidate cellulase enzyme, Celcm05-2, to a state of homogeneity. The enzyme belonged to GH5 subfamily 4 and exhibited robust enzymatic activity under acidic pH conditions. It maintained hydrolytic activity under various environmental conditions, including the presence of metal ions, non-ionic surfactant Triton X-100, organic solvents, and varying temperatures. With an optimal temperature of 40 °C, Celcm05-2 showcased remarkable efficiency when deployed on crystalline cellulose (> 3.6 IU/mL), specifically Avicel, thereby positioning it as an attractive candidate for a myriad of biotechnological applications spanning biofuel production, paper and pulp processing, and textile manufacturing. Efficient biodegradation of waste paper pulp residues and the evidence of biopolishing suggested that Celcm05-2 can be used in the bioprocessing of cellulosic craft fabrics in the textile industry. Our findings suggest that the camel rumen microbiome can be mined for novel cellulase enzymes that can find potential applications across diverse biotechnological processes.

Gene selection using pyramid gravitational search algorithm

Genetics play a prominent role in the development and progression of malignant neoplasms. Identification of the relevant genes is a high-dimensional data processing problem. Pyramid gravitational search algorithm (PGSA), a hybrid method in which the number of genes is cyclically reduced is proposed to conquer the curse of dimensionality. PGSA consists of two elements, a filter and a wrapper method (inspired by the gravitational search algorithm) which iterates through cycles. The genes selected in each cycle are passed on to the subsequent cycles to further reduce the dimension. PGSA tries to maximize the classification accuracy using the most informative genes while reducing the number of genes. Results are reported on a multi-class microarray gene expression dataset for breast cancer. Several feature selection algorithms have been implemented to have a fair comparison. The PGSA ranked first in terms of accuracy (84.5%) with 73 genes. To check if the selected genes are meaningful in terms of patient’s survival and response to therapy, protein-protein interaction network analysis has been applied on the genes. An interesting pattern was emerged when examining the genetic network. HSP90AA1, PTK2 and SRC genes were amongst the top-rated bottleneck genes, and DNA damage, cell adhesion and migration pathways are highly enriched in the network.

Metformin is a Novel Suppressor for Vimentin in Human Gastric Cancer Cell Line

Vimentin, an intermediate filament of mesenchymal cells, is upregulated in epithelial-mesenchymal transition (EMT) and has a main role in cancer metastasis. As a new strategy to control metastatic outgrowth, EMT markers are generally inhibited using some drugs or specific siRNA. In this study, AGS gastric cancer cells were treated with metformin and vimentin-specific siRNA (vim-siRNA) for 48 h. The impact of metformin and vim-siRNA on vimentin downregulation in AGS cells were analyzed by quantitative PCR and Western blot. Following treatment with metformin and vim-siRNA, cell motility, migration and invasion abilities of AGS cells were also analyzed. The results showed that inhibition of vimentin due to metformin was comparable with the vim-siRNA. Furthermore, wound-healing and invasion assays showed a significant decrease in migration and invasion of AGS cells following metformin and vim-siRNA treatment. Our finding for the first time indicated that metformin can be an alternative to specific siRNA for inhibition of vimentin expression and migration of AGS cell line. Taken together, our data indicates that the use of metformin might have a priority to siRNA for inhibition of gastric cancer cell behaviors siRNA is more unstable and expensive than metformin, and needs special vehicles and delivery strategies for efficient transfection of cells. Further in vivo studies can reveal metformin's potential in inhibition of EMT and metastasis of cancer cells.

Effects of hydrogen peroxide, doxorubicin and ultraviolet irradiation on senescence of human dental pulp stem cells

OBJECTIVE

The objective of this study was to evaluate the ability of three distinct agents on the induction of senescence in human dental pulp stem cells (DPSCs).

DESIGN

DPSCs from three separate donors were treated with H₂O₂, doxorubicin and ultraviolet (UV) irradiation. The response of the cells to the three agents was assayed by specific staining for SA-βGal, RT-qPCR and flow cytometry.

RESULTS

The results showed that incubation with 100 μM H₂O₂ and 20 nM Doxorubicin for seven days led to senescence in all donors' cells equally. Interestingly, UV irradiation for just one minute was sufficient to induce senescence in the cells. The SA-βGal positive senescent cells were arrested in G₁ phase and their S phase was significantly reduced as analyzed by flow cytometry. Significant increment in p21 and BTG1 expression and decrement in CCND1 expression also confirmed the cells have been arrested and get senescent via p53-p21 pathway.

CONCLUSION

All three agents successfully triggered senescence in the cells. There was no significant difference in the capacity of the three donor's cells for senescence. To avoid premature senescence in stem cell in vitro, it is recommended to avoid unnecessary exposure of the cell to fluorescent and UV light. Moreover, to prevent ROS production, we recommend using a separate incubator with low oxygen content for cell culture, if possible.

Cytotoxic and anti-proliferative effects of Rosa beggeriana Schrenk extracts on human liver and breast cancer cells

OBJECTIVE

Rosa beggeriana Schrenk has been consumed in Iranian traditional medicine. In contrary to its close species (e.g. R. canina), there is no data on its medicinal properties. Therefore, we explored possible cytotoxic effects of R. beggeriana against two cancer cell lines.

MATERIALS AND METHODS

The cytotoxic and anti-proliferative effects of R. beggeriana ethanolic and aqueous extracts on human liver cancer cells (LCLPI 11), breast cancer cells (MCF-7) and fibroblast-like cells (HSkMC) were evaluated by MTT, BrdU and TUNEL assays.

RESULTS

Following 48 h, IC₅₀ values for LCL-PI11 and MCF-7 cells were found to be 3.9 and 4.2 μg/mL for aqueous extract, and 2.3 and 2.7 μg/mL for ethanolic extract, respectively.BrdU assay data verified the MTT results and showed that both extracts inhibit cell proliferation as much as 5-fluorouracil does (p<0.05). The ethanolic extract had a more marked inhibitory effect compared to the aqueous extract (p<0.05). Besides both extracts were less effective against HSKMC cells compared to other cells lines.TUNEL assay results demonstrated that following 48 h, the aqueous extract induced about 19 and 24% apoptotic death in the LCL-PI 11 and MCF-7 cells, respectively (p<0.05). While at the same time, the ethanolic extract was more potent and caused about 83 and 91% death in the LCL-PI 11 and MCF-7 cells, respectively (p<0.05).

CONCLUSION

These data indicate that both extracts have anti-proliferative and pro-apoptotic activities on these two cancer cell lines and these effects were more pronounced then their activities against normal cells. Also, the ethanolic extract was more potent than the aqueous extract. Further researches are necessary for finding and isolating effective anticancer ingredient of R. beggeriana.

Long noncoding RNA VIM-AS1 promotes colorectal cancer progression and metastasis by inducing EMT

Emerging evidence indicates that lncRNAs play crucial roles in the initiation and progression of various malignant tumors. VIM-AS1 RNA is an lncRNA that transcribes from a shared bidirectional promoter with vimentin mRNA and its function in cancer cells is largely unknown. This study assessed the clinical significance of VIM-AS1 expression in colorectal cancer (CRC). We found that the VIM-AS1 transcript was significantly upregulated in high-grade, lymph node metastasis and vascular invasion tumors. Loss-of-function experiments revealed that the downregulation of VIM-AS1 could inhibit tumor cell proliferation by inducing apoptosis, cellular senescence and arresting the cell cycle. Moreover, the obtained data demonstrated that VIM-AS1 might play a crucial role in cell migration as well as the epithelial to mesenchymal transition (EMT) of CRC cells. Collectively, for the first time, our data provide novel evidence for the biological and clinical significance of VIM-AS1 expression in CRC. Further, the findings of this study suggest that VIM-AS1 promotes tumor growth and metastasis by inducing EMT in CRC cells and could be considered as a novel tumor marker with probable value in diagnosis and CRC treatment.

In-Vitro Anti-Proliferative and Pro-Apoptotic Properties of Sutureja Khuzestanica on Human Breast Cancer Cell Line (MCF-7) and Its Synergic Effects with Anticancer Drug Vincristine

Satureja khuzestanica Jamzad (Marzeh Khuzestani in Persian) is an endemic plant that is widely distributed in the southern part of Iran. Despite the number of papers published on this plant, no one has focused on its anticancer effects. Therefore, the present study was designed to investigate the selective cytotoxic and anti-proliferative properties of satureja khuzestanica total extract (SKE). MCF-7 human breast cancer cells were used in this study. Cytotoxicity of the extract was determined using MTT and neutral red assaysafter 24 h treatment period. Biochemical markers of apoptosis (caspase-3, Bax, Bcl-2) and cell proliferation (cyclin D1) were evaluated by immunoblotting. Vincristine was used to evaluate the synergic effect of extract with an anticancer drug. The data showed that treatment of cells with SKE (150 and 200 µg/mL for 24 h) significantly reduced cell viability, activated caspase 3 and increased Bax/Bcl2 ratio. In addition, cyclin D1 expression was significantly decreased in the SKE-treated cells. In addition, concomitant treatment of the MCF-7 cells with SKE and vincristine produced a potent anti-proliferative and pro-apoptotic effect compared to extract or drug alone. In conclusion, satureja extract has a potential anti-cancer property against human breast cancer cells and its combination with chemotherapeutic agent vincristine may induce cell death effectively and be a potent modality to treat this type of cancer.

Cytotoxic effects of Fritillaria imperialis L. extracts on human liver cancer cells, breast cancer cells and fibroblast-like cells

In this study, we evaluated the cytotoxic effects of Fritillaria imperialis L. aqueous and ethanolic extracts on human liver cancer cells (LCL-PI 11), breast adenocarcinoma cells (MCF-7) and fibroblast-like cells (HSkMC). MTT, BrdU and TUNEL assays were used to detect cytotoxicity, proliferation rate and apoptotic death. Following 48h, the IC₅₀ values for LCL-PI11 and MCF-7 cells were 4.2 and 3.9μg/mL of aqueous extract, and 1.7 and 1.3μg/mL of ethanolic extract, respectively, which was comparable to that of 5-FU. BrdU assay data verified that both extracts inhibited cell proliferation more preferentially on the two cancer cells. Exposure of LCL-PI 11 and MCF-7 cells to 2.4μg/mL of aqueous extract for 24h resulted in 29% and 32% apoptotic death. Surprisingly the ethanolic extract killed nearly all of the cells at 1.6μg/mL concentration. Collectively, our data indicated that both extracts have cytotoxic, cytostatic and pro-apoptotic activities against the two cancer cell lines. The ethanolic extract was more potent than the aqueous extract and the fibroblast cell was found to be less influenced than both cancer cell lines. Further researches are necessary for chemical characterization and in vivo evaluation especially in animal models to identify the effective anticancer ingredient of F. imperialis.

Trimethylamine-N-Oxide Treatment Induces Changes in the ATP-Binding Cassette Transporter A1 and Scavenger Receptor A1 in Murine Macrophage J774A.1 cells

BACKGROUND

Recently, trimethylamine N-oxide was introduced as a risk factor for atherosclerosis in terms of helping foam cell formation and worsening atherosclerosis complications. The present study was performed to investigate whether/how trimethylamine N-oxide is involved in regulation of ATP-binding cassette transporter A1 and scavenger receptor A1 in macrophages at both mRNA and protein levels.

METHODS

Murine macrophage J774A.1 cells were treated with micromolar concentrations of trimethylamine N-oxide and 4-phenylbutyric acid, a chemical chaperon, for different time intervals. Tunicamycin was also used as a control for induction of endoplasmic reticulum stress.

RESULTS

Similar to tunicamycin, trimethylamine N-oxide increased scavenger receptor A1 in all treatment periods, whereas ATP-binding cassette transporter A1 was only reduced 24 h post-treatment with trimethylamine N-oxide at both mRNA and protein levels. In contrast, 4-phenylbutyric acid failed to induce such changes in either scavenger receptor A1 or ATP-binding cassette transporter A1.

CONCLUSIONS

The results of this study, in agreement with previous studies, confirm the mechanistic role of trimethylamine N-oxide in the upregulation of scavenger receptor A1, which potentially can promote its proatherogenic role. The results also showed downregulation of ATP-binding cassette transporter A1 in trimethylamine N-oxide treated macrophages which may indicate another possible proatherosclerotic mechanism for foam cell formation.

HSP90 inhibitor enhances anti-proliferative and apoptotic effects of celecoxib on HT-29 colorectal cancer cells via increasing BAX/BCL-2 ratio

Due to the high prevalence and mortality rate of colorectal cancer (CRC), new treatment approaches like combination therapy seem to be necessary. The relationship between chronic inflammation and colorectal cancer development and progression has been shown to be important. Celecoxib, a selective COX-2 inhibitor, is the only non-steroidal anti-inflammatory drug (NSAID) that has been approved for cancer therapy and prevention. Because of cardiovascular side effects of COX-2 inhibitors, combination therapy may improve the therapeutic profile. 17-Demethoxy-17-allylamino geldanamycin (17-AAG), a heat shock protein 90 (HSP90) inhibitor, shows anti-inflammatory effects via down-regulation of the key mediators of inflammation such as Nuclear Factor κB (NF-kB), JAK/Signal Transducer and Activator of Transcription (JAK/STAT). Thus, we studied the effect(s) of combination of 17-AAG and celecoxib on HT-29 cells viability and apoptosis induction. Based on MTT results, we showed an increase in the inhibitory effect of celecoxib when combined with 17-AAG, especially at low a concentration of celecoxib.  Flow cytometry analysis demonstrated that apoptosis induction is probably the mechanism of additive inhibitory effects of 17-AAG and celecoxib combination. To explore the possible mechanism of apoptosis induction by 17-AAG and celecoxib combination, levels of BAX and BCL-2 proteins were determined by western blotting. The BAX/BCL-2 ratio in the combination group was increased compared to 17-AAG or celecoxib alone, mainly via decreasing BCL-2 levels. In conclusion, 17-AAG, increased inhibitory effects of celecoxib on HT-29 cells, probably by induction of apoptosis.

Differential Expression of Hox and Notch Genes in Larval and Adult Stages of Echinococcus granulosus

This investigation aimed to evaluate the differential expression of HoxB7 and notch genes in different developmental stages of Echinococcus granulosus sensu stricto. The expression of HoxB7 gene was observed at all developmental stages. Nevertheless, significant fold differences in the expression level was documented in the juvenile worm with 3 or more proglottids, the germinal layer from infected sheep, and the adult worm from an experimentally infected dog. The notch gene was expressed at all developmental stages of E. granulosus; however, the fold difference was significantly increased at the microcysts in monophasic culture medium and the germinal layer of infected sheep in comparison with other stages. The findings demonstrated that the 2 aforementioned genes evaluated in the present study were differentially expressed at different developmental stages of the parasite and may contribute to some important biological processes of E. granulosus.

Isolation and evaluation of dental pulp stem cells from teeth with advanced periodontal disease

INTRODUCTION

Successful isolation of mesenchymal stem cells from waste tissues might be extremely promising for developing stem cell-based therapies. This study aimed to explore whether cells retrieved from teeth extracted due to advanced periodontal disease present mesenchymal stem cell-like properties.

METHODS

Pulp cells were isolated from 15 intact molars and 15 teeth with advanced periodontal disease. Cell proliferation and markers of mesenchymal stem cells were evaluated.

RESULTS

Based on the RT-PCR and agarose gel electrophoresis, nucleostemin, Oct-4 and jmj2c, but not Nanog, were expressed in undifferentiated mesenchymal stem cells of both groups. Interestingly, diseased pulp exhibited higher gene expressions although it was not statistically significant. The average percentage of BrdU positive cells in the diseased group (84.4%, n = 5) was significantly higher than that of the control group (65.4%, n = 5) (t-test, P = 0.001).

CONCLUSION

Our results indicate the successful isolation of mesenchymal stem cells from the pulp tissue of hopeless periodontally involved teeth.

Expression levels of heat shock protein 60 and glucose-regulated protein 78 in response to trimethylamine-N-oxide treatment in murine macrophage J774A.1 cell line

Trimethylamine N-oxide (TMAO), a common metabolite in animals and humans, can induce changes in the expression or conformation of heat shock proteins. It has also been introduced as a risk factor for atherosclerosis and a biomarker for kidney problems. On the other hand, increased levels of heat shock proteins 60 and 70 KDa are associated with increased atherosclerosis risk. This study was therefore designed to evaluate the possible effect(s) of TMAO on the expression of HSP60 and GRP78 at the mRNA and protein levels. Murine macrophage J774A.1 cells were treated with micromolar concentrations of TMAO and 4-phenylbutyric acid (4-PBA), a chemical chaperon, for different time intervals. Tunicamycin was also used as a control for induction of endoplasmic reticulum stress. Tunicamycin greatly increased both mRNA and protein levels of GRP78. Similarly but to a lesser extent compared to tunicamycin, TMAO also increased mRNA and protein levels of GRP78 in a dose and time-dependent manner. In contrast, 4-PBA failed to induce any changes. Similar to GRP78, HSP60 was also increased only at mRNA level in TMAO treated cells. 4-PBA also increased HSP60 mRNA levels, whereas, tunicamycin did not show any effect on either protein or mRNA levels of HSP60. Since both heat shock proteins are stress inducible and the elevation of GRP78 is a hallmark for endoplasmic reticulum stress induction, it can be concluded that TMAO may induce endoplasmic reticulum stress or may act through elevation of these heat shock proteins.

Tetracycline-regulated expression of OLIG2 gene in human dental pulp stem cells lead to mouse sciatic nerve regeneration upon transplantation

Numerous studies have indicated dental pulp stem cells (DPSCs) potency to differentiate into several types of cell lineages. Oligodendrocyte lineage transcription factor 2 (OLIG2) plays an important role in the oligodendrogenic pathway. In this study, a tetracycline (Tet)-inducible system expressing OLIG2 gene was transfected into human DPSCs to direct their differentiation toward oligodendrocyte progenitor cells (OPCs). Following induction, the expression of stage-specific markers was studied by Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), immunocytochemistry and western blotting. In the following, the cells were transplanted into the mouse model of local sciatic demyelination damage by lysolecithin. Recovery of lysolecithin-induced lesions in sciatic nerve was studied by treadmill exercise, von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Improvement of behavioral symptoms was efficiently observed from the second week to the sixth week post-transplantation. Our findings showed that exogenous expression of the OLIG2 gene by a Tet-regulated system could be used as an efficient way to induce the differentiation of DPSCs into functional oligodendrocytes. Meanwhile, the DPSC-derived OPCs have relevant therapeutic potential in the animal model of sciatic nerve injury and therefore might represent a valuable tool for stem cell-based therapy in inflammatory and degenerative diseases of the peripheral and central nervous systems (CNSs).

Human Dental Pulp Stem Cells Differentiate into Oligodendrocyte Progenitors Using the Expression of Olig2 Transcription Factor

The helix-loop-helix transcription factor Olig2 is essential for lineage determination of oligodendrocytes. Differentiation of stem cells into oligodendrocytes and transplanting them is a novel strategy for the repair of different demyelination diseases. Dental pulp stem cells (DPSCs) are of great interest in regenerative medicine due to their potential for repairing damaged tissues. In this study, DPSCs were isolated from human third molars and transfected with the human Olig2 gene as a differentiation inducer for the oligodendrogenic pathway. Following the differentiation procedure, the expression of Sox2, NG2, PDGFRα, Nestin, MBP, Olig2, Oct4, glial fibrillary acidic protein and A2B5 as stage-specific markers was studied by real-time RT-qPCR, immunocytochemistry and Western blot analysis. The cells were transplanted into a mouse model of local sciatic damage by lysolecithin as a model for demyelination. Oligodendrocyte progenitor cells (OPCs) actively remyelinated and recovered the lysolecithin-induced damages in the sciatic nerve as revealed by treadmill exercise, the von Frey filament test and hind paw withdrawal in response to a thermal stimulus. Recovery of behavioral reflexes occurred 2-6 weeks after OPC transplantation. The results demonstrate that the expression of Olig2 in DPSCs reduces the expression of stem cell markers and induces the development of oligodendrocyte progenitors as revealed by the emergence of oligodendrocyte markers. DPSCs could be programmed into oligodendrocyte progenitors and considered as a simple and valuable source for the cell therapy of neurodegenerative diseases.

Inhibition of 6-hydroxydopamine-induced PC12 cell apoptosis by olive (Olea europaea L.) leaf extract is performed by its main component oleuropein

Parkinson disease (PD) is the most common progressive neurodegenerative disorder characterized by progressive death of midbrain dopaminergic neurons. Most neurodegenerative disease treatments are, at present, palliative. However, some natural herbal products have been shown to rescue neurons from death and apoptosis in some of neurodegenerative diseases. Not only Olea europaea L. olive oil, but also the leaves of this plant have been used for medical purposes. Olive leaf extract (OLE) is being used by people as a drink across the world and as an integral ingredient in their desire to maintain and improve their health. Here, we investigated the effects of OLE and its main phenolic component oleuropein on 6-hydroxydopamine (6-OHDA)-induced toxicity in rat adrenal pheochromocytoma (PC12) cells as an in vitro model of PD. Cell damage was induced by 150 μM 6-OHDA. The cell survival rate was examined by MTT assay. Generation of intra-cellular reactive oxygen species (ROS) was studied using fluorescence spectrophotometry. Immunoblotting and DNA analysis were also employed to determine the levels of biochemical markers of apoptosis in the cells. The data showed that 6-OHDA could decrease the viability of the cells. In addition, intra-cellular ROS, activated caspase 3, Bax/Bcl-2 ratio, as well as DNA fragmentation were significantly increased in 6-OHDA-treated cells. Incubation of cells with OLE (400 and 600 μg/mL) and oleuropein (20 and 25 μg/mL) could decrease cell damage and reduce biochemical markers of cell death. The results suggest that OLE and oleuropein have anti-oxidant protective effects against 6-OHDA-induced PC12 cell damage. The protective effects of OLE and oleuropein are correlative with their anti-oxidative and anti-apoptotic properties and suggest their therapeutic potential in the treatment of PD.

A modified efficient method for dental pulp stem cell isolation

BACKGROUND

Dental pulp stem cells can be used in regenerative endodontic therapy. The aim of this study was to introduce an efficient method for dental pulp stem cells isolation.

MATERIALS AND METHODS

In this in-vitro study, 60 extracted human third molars were split and pulp tissue was extracted. Dental pulp stem cells were isolated by the following three different methods: (1) digestion of pulp by collagenase/dispase enzyme and culture of the released cells; (2) outgrowth of the cells by culture of undigested pulp pieces; (3) digestion of pulp tissue pieces and fixing them. The cells were cultured in minimum essential medium alpha modification (αMEM) medium supplemented with 20% fetal bovine serum(FBS) in humid 37°C incubator with 5% CO 2. The markers of stem cells were studied by reverse transcriptase polymerase chain reaction (PCR). The student t-test was used for comparing the means of independent groups. P <0.05 was considered as significant.

RESULTS

The results indicated that by the first method a few cell colonies with homogenous morphology were detectable after 4 days, while in the outgrowth method more time was needed (10-12 days) to allow sufficient numbers of heterogeneous phenotype stem cells to migrate out of tissue. Interestingly, with the improved third method, we obtained stem cells successfully with about 60% efficiency after 2 days. The results of RT-PCR suggested the expression of Nanog, Oct-4, and Nucleostemin markers in the isolated cells from dental pulps.

CONCLUSION

This study proposes a new method with high efficacy to obtain dental pulp stem cells in a short time.

The role of GABAergic system on the inhibitory effect of ghrelin on food intake in neonatal chicks

Ghrelin is a gut-brain peptide that has a stimulatory effect on food intake in mammals. In contrast, this peptide decreases food intake in neonatal chicks when injected intracerebroventricularly (ICV). In mammals, neuropeptide Y (NPY) mediates the orexigenic effect of ghrelin whereas in chicks it appears that corticotrophin releasing factor (CRF) is partially involved in the inhibitory effect of ghrelin on food intake. Gamma aminobutyric acid (GABA) has a stimulatory effect on food intake in mammals and birds. In this study we investigated whether the anorectic effect of ghrelin is mediated by the GABAergic system. In Experiment 1, 3h-fasted chicks were given an ICV injection of chicken ghrelin and picrotoxin, a GABA(A) receptors antagonist. Picrotoxin decreased food intake compared to the control chicks indicating a stimulatory effect of GABA(A) receptors on food intake. However, picrotoxin did not alter the inhibitory effect of ghrelin on food intake. In Experiment 2, THIP hydrochloride, a GABA(A) receptor agonist, was used in place of picrotoxin. THIP hydrochloride appeared to partially attenuate the decrease in food intake induced by ghrelin at 30 min postinjection. In Experiment 3, the effect of ICV injection of chicken ghrelin on gene expression of glutamate decarboxylase (GAD)(1) and GAD(2), GABA synthesis enzymes in the brain stem including hypothalamus, was investigated. The ICV injection of chicken ghrelin significantly reduced GAD(2) gene expression. These findings suggest that ghrelin may decrease food intake in neonatal chicks by reducing GABA synthesis and thereby GABA release within brain feeding centers.

Expression analysis and purification of human recombinant tissue type plasminogen activator (rt-PA) from transgenic tobacco plants

Recombinant tissue-type plasminogen activator (rt-PA) has been produced in different hosts. In this research, transgenic tobacco was selected for production of human rt-PA. Transgenic plants were analyzed by polymerase chain reaction (PCR) and reverse-transcription (RT)-PCR. The protein was extracted by Lysine Sepharose chromatography column and was further purified by HiTrap desalting column. The function of eluted protein was analyzed on zymography gel. The results showed that the 1.7-kb cDNA of tissue-type plasminogen activator (t-PA) (as well as a shortened 650-bp transcript of t-PA) has been expressed in transgenic plants. The anticipated 63-kD protein band and an additional 53-kD protein were observed in transgenic plants. Finally, zymography assay revealed that the purified rt-PA has anticipated appropriate activity comparable to a positive control drug (Alteplase). On the whole, we can say that transgenic tobacco is a good alternative host for production of t-PA.

NGF and BDNF expression drop off in neurally differentiated bone marrow stromal stem cells

Bone marrow stromal stem cells (BMSC) express two neurotrophins nerve growth factor (NGF) and brain derived growth factor (BDNF) constitutively and can be differentiated into neuronal-like cells and used to treat neural injuries and diseases. The neurotrophins are required for repair of neural tissues. However, it is not evident whether these cells supply the sufficient amounts of the functional growth factors following neuronal differentiation. This study investigates the expression of NGF, BDNF and their processing enzymes Prohormone convertases (PC) Furin, PC5 and PC6 by Real-time RT-PCR during neural differentiation of rat BMSC. The results showed that all inspected processing enzymes are expressed in the cells. The expression of NGF, BDNF and PC5 decreases following differentiation. In addition, BMSCs express Survivin, an anti-apoptotic gene; however, the differentiated cells reduce its expression similar to two neurotrophins, which could make them susceptible to apoptotic death.

Proprotein convertases 1 and 2 (PC1 and PC2) are expressed in neurally differentiated rat bone marrow stromal stem cells (BMSCs)

Neural-like cells derived from bone marrow stromal stem cells (BMSCs) have potential usefulness in cell therapy of degenerative or traumatic diseases of the central nervous system (CNS). The functional recovery mediated by these cells, however, depends on the secretion of neurotrophins (NTs) and their cognate receptors, as the main regulators of neural survival and death. The function of NTs is further modulated by proprotein convertase (PC) enzymes which function in converting proproteins (including proNTs) into their functional end products. Accordingly, failure in converting proprotein forms of NTs into their mature forms may lead to neuronal cell death. In the present study, we have investigated the expression profile of PCs before and during neural differentiation of rat BMSCs by RT-PCR. Our results show that major members of the PC family functioning in the constitutive secretory pathway (furin, PACE4 and PC7/LPC) are highly expressed in both undifferentiated and neurally differentiated BMSCs. In contrast, while PC1/PC3 and PC2 (specific to neural and endocrine cells) are absent in undifferentiated BMSCs, their expression is initiated upon the induction of differentiation. In conclusion, our results suggest that neurally differentiated BMSCs have acquired the functional machinery to process the precursor forms of proteins in both the constitutive and regulated pathways.

Differential gene expression pattern of neurotrophins and their receptors during neuronal differentiation of rat bone marrow stromal cells

Neural-like cells derived from bone marrow stromal cells (BMSC) have potential usefulness in repair of the CNS injuries or diseases. The functional recovery mediated by these cells, however, depends on secretion of specific growth factors and their designated receptors. In the present study, we have investigated the expression profile of neurotrophins NGF, BDNF and NT-3 and their high-affinity (TrkA, TrkB, TrkC) and common low-affinity (p75NTR) receptors before and during neural differentiation of rat BMSCs by RT-PCR. Results indicate that NGF and BDNF but not NT-3 are expressed in both un-differentiated as well as neurally differentiated BMSCs. In contrast, the expression of TrkA and TrkB is restricted to neurally differentiated cells, while TrkC is not expressed in these cells either before or after differentiation. Interestingly, p75NTR expression is absent in un-differentiated cells but is initiated upon the induction of neural differentiation, and then shut off in fully differentiated neuron-like cells.

Nucleostemin, a coordinator of self-renewal, is expressed in rat marrow stromal cells and turns off after induction of neural differentiation

Bone marrow stromal cells (BMSCs) are pluripotent stem cells with self-renewal property and potential to differentiate into a variety of cell types. Identification of the genes responsible for coordination of these processes and elucidation of the mechanisms underlying these events are of fundamental importance. Nucleostemin, a novel p53 binding protein localized in the nucleoli of ESCs, is not expressed in the differentiated cells of adult tissue, suggesting a role in maintaining stem cell self-renewal. In the present study, we have evaluated the expression profile of nucleostemin in rat BMSCs before and after the induction of neural differentiation by RT-PCR and immunocytochemistry. The profile of nucleostemin expression is then compared to the key regulators of proliferation/differentiation such as: Oct-4, Nanog, Neuro D, and Cyclin D1. Our data reveal that there is no detectable expression of Oct-4 and Nanog in either non-differentiated or neurally differentiated BMSCs. In contrast, the expression of nucleostemin is relatively high in non-differentiated BMSCs, then sharply diminishes upon induction of differentiation and finally completely vanishes by 6h after initiation of differentiation. The disappearance of nucleostemin expression coincides with the appearance of Neurofilament-M and -H, MAP2, synaptophysin- and neuron-specific enolase as revealed by RT-PCR and/or immunocytochemistry. Expression of Neuro D and Cyclin D1 also diminish as differentiation proceeds but at much slower rates as compared to nucleostemin. In conclusion, our results suggest that nucleostemin, but not Oct-4 or Nanog, is expressed in BMSCs and it possibly regulates self-renewal proliferation in BMSCs.