MicroRNAs Signature in IL-2-Induced CD4+ T Cells and Their Potential Targets.

MicroRNAs (miRNAs) are a class of small non-coding RNAs regulated gene expression at the post-transcriptional level. Many studies have investigated role of miRNAs in the biological processes such as proliferation, apoptosis, differentiation, and development. To evaluate role of miRNAs in proliferation and death of T cell, we performed miRNA profiling in activated CD4+ T cells after IL-2 induction and depletion. Proliferation rate of IL-2-induced cells was measured by MTT assay. Then quantitative RT-PCR arrays on 739 miRNAs revealed up- and down-regulation of 170 miRNAs in IL-2-induced CD4+ T cells relative to IL-2-depleted ones. In addition, in silico analysis predicted miRNA's potential targets in pathways such as JAK/STAT and PI3K pathways. JAK1 expression, a potential target of modulated miRNAs, was decreased in IL-2-depleted cells. This study suggests that clonal expansion is regulated by miRNAs in the absence or presence of IL-2 by targeting genes implicated in JAK/STAT and PI3K pathways.

FOXC1 in human trabecular meshwork cells is involved in regulatory pathway that includes miR-204, MEIS2, and ITGß1.

Forkhead box C1 (FOXC1) is a transcription factor that affects eye development. FOXC1 is implicated in the etiology of glaucoma because mutations in the gene are among the causes of Axenfeld-Rieger syndrome which is often accompanied by glaucoma. Glaucoma is the second leading cause of blindness. It is a complex disorder whose genetic basis in most patients remains unknown. Microarrays expression analysis was performed to identify genes in human trabecular meshwork (TM) primary cultures that are affected by FOXC1 and genes that may have roles in glaucoma. This represents the first genome wide analysis of FOXC1 target genes in any tissue. FOXC1 knock down by siRNAs affected the expression of 849 genes. Results on selected genes were confirmed by real time PCR, immunoblotting, and dual luciferase reporter assays. Observation of MEIS2 as a FOXC1 target and consideration of FOXC1 as a potential target of miR-204 prompted testing the effect of this micro RNA on expression of FOXC1 and several genes identified by array analysis as FOXC1 target genes. It was observed that miR-204 caused decreased expression of FOXC1 and the FOXC1 target genes CLOCK, PLEKHG5, ITGß1, and MEIS2 in the TM cultures. Expression of CLOCK, PLEKHG5, ITGß1 has not previously been reported to be affected by miR-204. The data suggest existence of a complex regulatory pathway in the TM part of which includes interactions between FOXC1, miR-204, MEIS2, and ITGß1. All these molecules are known to have TM relevant functions, and the TM is strongly implicated in the etiology of glaucoma.

LTBP2 mutations cause Weill-Marchesani and Weill-Marchesani-like syndrome and affect disruptions in the extracellular matrix.

Latent transforming growth factor (TGF) beta-binding protein 2 (LTBP2) is an extracellular matrix (ECM) protein that associates with fibrillin-1 containing microfibrils. Various factors prompted considering LTBP2 in the etiology of isolated ectopia lentis and associated conditions such as Weill-Marchesani syndrome (WMS) and Marfan syndrome (MFS). LTBP2 was screened in 30 unrelated Iranian patients. Mutations were found only in one WMS proband and one MFS proband. Homozygous c.3529G>A (p.Val1177Met) was shown to cause autosomal recessive WMS or WM-like syndrome by several approaches, including homozygosity mapping. Light, fluorescent, and electron microscopy evidenced disruptions of the microfibrillar network in the ECM of the proband's skin. In conjunction with recent findings regarding other ECM proteins, the results presented strongly support the contention that anomalies in WMS patients are due to disruptions in the ECM. Heterozygous c.1642C >T (p.Arg548*) possibly contributed to MFS-related phenotypes, including ocular manifestations, mitral valve prolapse, and pectus excavatum, but was not cause of MFS.

Non-housekeeping genes expressed in human trabecular meshwork cell cultures.

PURPOSE: To identify non-housekeeping genes definitively expressed in the human trabecular meshwork (TM). METHODS: Microarray gene expression data on TM cultured cells from four studies were compared. Genes that were queried in at least three studies and assessed to be expressed in at least three studies were considered definitively expressed genes of the human TM. Housekeeping genes were removed from this set of genes. The non-housekeeping TM gene profile was analyzed for pathway enrichment and microRNA targeting, using bioinformatics tools. The results were compared with results of previous non-array based studies. RESULTS: Nine hundred and sixty-two genes were identified as non-housekeeping TM expressed genes. Analysis of these by Kyoto Encyclopedia of Genes and Genomes led to identification of two enriched biologic pathways that achieved a highly significant Bonferroni p-value (p≤0.01): focal adhesion and extracellular matrix (ECM)-receptor interaction. Many of the genes were previously implicated in TM-related functions and the TM-associated disease glaucoma; however, some are novel. MicroRNAs known to be expressed in the trabecular meshwork were predicted to target some of the genes. Ten genes identified here, ALDH1A1 (aldehyde dehydrogenase 1 family, member A1), CDH11 (cadherin 11, type 2, OB-cadherin), CXCR7 (chemokine (C-X-C motif) receptor 7), CHI3L1 (chitinase 3-like 1), FGF2 (fibroblast growth factor 2), GNG11 (guanine nucleotide binding protein [G protein], gamma 11), IGFBP5 (insulin-like growth factor binding protein 5), PTPRM (protein tyrosine phosphatase, receptor type, M), RGS5 (regulator of G-protein signaling 5), and TUSC3 (tumor suppressor candidate 3), were also reported as TM expressed genes in three earlier non-microarray based studies. CONCLUSIONS: A transcriptome consisting of 962 non-housekeeping genes definitively expressed in the human TM was identified. Multiple genes and microRNAs are proposed for further study for a better understanding of TM physiology.

MicroRNA signature associated with osteogenic lineage commitment.

Cell-based approaches offer a potential therapeutic strategy for appropriate bone manufacturing. Capable of differentiating into multiple cell types especially osteoblasts spontaneously, unrestricted somatic stem cell (USSC) seems to be a suitable candidate. Recent studies have shown the involvement of microRNAs in several biological processes. miRNA microarray profiling was applied in order to identify the osteo-specific miRNA signature. Prior to this analysis, osteogenic commitment of osteoblasts was evaluated by measuring ALPase activity, biomineralization, specific staining and evaluation of some main osteogenic marker genes. To support our findings, various in silico explorations (for both putative targets and signaling pathways) and empirical analyses (miRNA transfections followed by qPCR of osteogenic indicators and ALPase activity measurement) were carried out. The function of GSK-3b inhibitor was also studied to investigate the role of WNT in osteogenesis. Transient modulation of multiple osteo-miRs (such as mir-199b, 1274a, 30b) with common targets (such as BMPR, TCFs, SMADs) as mediators of osteogenic pathways including cell-cell interactions, WNT and TGF-beta pathways, suggests a mechanism for rapid induction of the osteogenesis as an anti-miRNA therapy. The results of this research have identified the miRNA signature which regulates the osteogenesis mechanism in USSC. To conclude, our study reveals more details about the allocation of USSCs into osteogenic lineage through modulatory effect of miRNAs on targets and pathways required for creating a tissue-specific phenotype and may aid in future clinical interventions.

Loss of function mutations in the gene encoding latent transforming growth factor beta binding protein 2, LTBP2, cause primary congenital glaucoma.

Glaucoma is a heterogeneous group of optic neuropathies that manifests by optic nerve head cupping or degeneration of the optic nerve, resulting in a specific pattern of visual field loss. Glaucoma leads to blindness if left untreated, and is considered the second leading cause of blindness worldwide. The subgroup primary congenital glaucoma (PCG) is characterized by an anatomical defect in the trabecular meshwork, and age at onset in the neonatal or infantile period. It is the most severe form of glaucoma. CYP1B1 was the first gene genetically linked to PCG, and CYP1B1 mutations are the cause of disease in 20-100% of patients in different populations. Here, we report that LTBP2 encoding latent transforming growth factor beta binding protein 2 is a PCG causing gene, confirming results recently reported. A disease-associated locus on chromosome 14 was identified by performing whole genome autozygosity mapping in Iranian PCG families using high density single nucleotide polymorphism chips, and two disease-segregating loss of function mutations in LTBP2, p.Ser472fsX3 and p.Tyr1793fsX55, were observed in two families while sequencing candidate genes in the locus. The p.Tyr1793fsX55 mutation affects an amino acid close to the C-terminal of the encoded protein. Subsequently, LTBP2 expression was shown in human eyes, including the trabecular meshwork and ciliary processes that are thought to be relevant to the etiology of PCG.

Effect of PITX2 knockdown on transcriptome of primary human trabecular meshwork cell cultures.

PURPOSE: To identify genes whose expressions in primary human trabecular meshwork (TM) cell cultures are affected by the transcription factor pituitary homeobox 2 (PITX2) and to identify genes that may have roles in glaucoma. Known glaucoma causing genes account for disease in a small fraction of patients, and we aimed at identification of other genes that may have subtle and accumulative effects not easily identifiable by a genetic approach. METHODS: Expression profiles derived using microarrays were compared between TM control cells and cells treated with PITX2 siRNAs using three protocols so as to minimize false positive and negative results. The first protocol was based on the commonly used B statistic. The second and third protocols were based on fold change in expression. The second protocol used a threshold of at least 2 fold change in expression, whereas the third protocol used ranking in fold change without setting a threshold. The likelihood of a selected gene being a true positive was considered to correlate with the number of protocols by which it was selected. By considering all genes that were selected by at least one protocol, the likelihood of false negatives was expected to decrease. Effects on a subset of selected genes were verified by real time PCR, western blots, and immunocytochemistry. Effects on ALDH1A1, were further pursued because its protein product, aldehyde dehydrogenase 1 family, member A1, has roles in oxidative stress and because oxidative stress is known to be relevant to the etiology of glaucoma. RESULTS: The expression level of 41 genes was assessed by to be possibly affected by PITX2 knockdown. Twenty one genes were down-regulated and twenty were upregulated. The expression of five genes was assessed to be altered by all three analysis protocols. The five genes were DIRAS3 (DIRAS family, GTP-binding RAS-like 3), CXCL6 (chemokine (C-X-C motif) ligand 6), SAMD5 (sterile alpha motif domain containing 5), CBFB (core-binding factor, beta subunit), and MEIS2 (meis homeobox 2). Real time PCR experiments verified results on a subset of genes tested. Notably, the results were also confirmed in two independent TMs. Effects on CXCL6 and ALDH1A1 were also confirmed by western blots, and effects on ALDH1A1 were further shown by immunocytochemistry. Data consistent with PITX2 involvement in ALDH1A1 mediated response to oxidative stress were presented. CONCLUSIONS: Bioinformatics tools revealed that the genes identified affect functions and pathways relevant to glaucoma. Involvement of PITX2 in expression of some of the genes and in some of the pathways is being reported here for the first time. As many of the genes identified have not been studied vis-à-vis glaucoma, we feel they introduce new candidates for understanding this devastating disease.

Variable expressivity and high penetrance of CYP1B1 mutations associated with primary congenital glaucoma.

OBJECTIVE: To investigate penetrance and expressivity of CYP1B1 genotypes associated with primary congenital glaucoma (PCG). DESIGN: Observational case series, systematic review, and comparative analysis of the literature. PARTICIPANTS: Forty probands affected with PCG, 16 siblings affected with PCG, and 103 siblings and 75 parents of the probands reported not to be affected by history. The participants were members of 40 unrelated families. METHODS: Mutations were screened by restriction fragment length polymorphism, allele-specific polymerase chain reaction amplification, and direct sequencing. Ophthalmologic examination included slit-lamp biomicroscopy, intraocular pressure (IOP) measurement, gonioscopy, and high magnification stereoscopic fundus examination, followed by standard achromatic perimetry. MAIN OUTCOME MEASURES: Identification of subjects carrying CYP1B1 mutations. Glaucoma diagnosis based on slit-lamp examination, IOP measurement, gonioscopic findings, optic nerve appearance, and perimetry. RESULTS: Fifteen different homozygous or compound heterozygous mutant CYP1B1 genotypes were identified. Most probands and previously diagnosed subjects harbored G61E, R368H, R390H, and R469W mutations. Among the 178 apparently unaffected family members, 20 subjects from 12 families were observed to harbor 2 CYP1B1 mutations, suggesting an average penetrance of 73% for all the mutations. These 20 subjects ranged in age from 14 to 54 years. R390H appeared to have a notably high penetrance. Penetrance was 50% in the subset of families with incomplete penetrance. Ophthalmologic examination on 14 of the 20 apparently nonpenetrant individuals showed that 8 subjects were affected with juvenile open-angle glaucoma (JOAG) or primary open-angle glaucoma (POAG), and that 3 subjects were glaucoma suspect. One of the individuals with a JOAG diagnosis was the identical twin sibling of a proband affected with PCG. CONCLUSIONS: At least 57% of the PCG nonpenetrant individuals examined clinically were affected with JOAG or POAG to varying degrees, and overall penetrance of "affected CYP1B1 genotypes" with respect to glaucoma may be more than 90%. These findings suggest that "affected CYP1B1 genotypes" exhibit variable expressivity rather than nonpenetrance. The clinical implication of this observation is that seemingly unaffected relatives of patients with PCG, particularly those known to harbor CYP1B1 mutations, should undergo regular ophthalmologic examination to allow early diagnosis.

Screening of common CYP1B1 mutations in Iranian POAG patients using a microarray-based PrASE protocol.

PURPOSE: The gene coding cytochrome P4501B1 (CYP1B1) has been shown to be a major cause of primary congenital glaucoma in the Iranian population. More recently it was shown to also be important in juvenile-onset open angle glaucoma (JOAG). We aimed to further investigate the role of CYP1B1 in a larger cohort of primary open angle glaucoma (POAG) patients which included late-onset patients. We also aimed to set up a microarray based protocol for mutation screening with an intent of using the protocol in a future population level screening program. METHODS: Sixty three POAG patients, nine affected family members, and thirty three previously genotyped primary congenital glaucoma (PCG) patients were included in the study. Clinical examination included slit lamp biomicroscopy, IOP measurement, gonioscopic evaluation, fundus examination, and measurement of perimetry. G61E, R368H, R390H, and R469W were screened by a protocol that included multiplexed allele specific amplification in the presence of a protease (PrASE), use of sequence tagged primers, and hybridization to generic arrays on microarray slides. The entire coding sequences of CYP1B1 and myocilin (MYOC) genes were sequenced in all individuals assessed by the microarray assay to carry a mutation. Intragenic single nucleotide polymorphism (SNP) haplotpes were determined for mutated alleles. RESULTS: Genotypes assessed by the array-based PrASE methodology were in 100% concordance with sequencing results. Seven mutation carrying POAG patients (11.1%) were identified, and their distribution was quite skewed between the juvenile-onset individuals (5/21) as compared to late-onset cases (2/42). Four of the seven mutation carrying Iranian patients harbored two mutated alleles. CYP1B1 mutated alleles in Iranian PCG and POAG patients shared common haplotypes. MYOC mutations were not observed in any of the patients. CONCLUSIONS: The PrASE approach allowed reliable simultaneous genotyping of many individuals. It can be an appropriate tool for screening common mutations in large sample sizes. The results suggest that CYP1B1 is implicated in POAG among Iranians, notably in the juvenile-onset form. Contrary to POAG patients studied in other populations, many mutation harboring Iranian patients carry two mutated alleles. We propose an explanation for this observation.

Changes in the expression of OCT4 in mouse ovary during estrous cycle.

The transcriptional factor OCT4 regulates pluripotency of stem cells and has an important role during oocyte growth. Whereas, its role has remained ambiguous in ovarian tissue during reproductive cycle. Therefore, this study was aimed to investigate the expression patterns of OCT4 in mouse ovaries during the normal estrous cycle. Adult National Medical Research Institute mice were classified as proestrous, estrous, metestrous and diestrous on the basis of vaginal smear cytology. Their ovaries were removed and the protein and gene expression levels of OCT4 were assessed using immunohistochemical staining and real-time quantitative reverse-transcription PCR, respectively. Immunohistochemical staining revealed the expression of OCT4 in the cytoplasm of corpus luteum cells. In the follicles, OCT4 was expressed in the cytoplasm of granulosa cells. Furthermore, the gene expression levels of OCT4 was significantly higher in the proestrous phase than in the other phases of the estrous cycle (p < 0.05). The results indicated that OCT4 gene expression levels are affected by the cyclic pattern of the estrous cycle.

Screening for MIR184 Mutations in Iranian Patients with Keratoconus.

PURPOSE: To investigate whether microRNA (MIR)-184 mutations make a substantial contribution to keratoconus (KCN) among affected Iranian patients. METHODS: A total of 47 Iranian KCN patients, diagnosed based on family history, clinical examinations using slit lamp biomicroscopy, refraction and corneal topography were enrolled in this study. The pri-miR-184 encoding gene obtained from the DNAs of all participants was amplified using polymerase chain reaction and subsequently sequenced by the Sanger dideoxynucleotide protocol. The sequences were compared to MIR184 reference sequence in order to identify sequence variations. The potential effects of a single variation observed on RNA structure was predicted. RESULTS: Only one sequence variation, +39G >T, was observed within the pri-miR-184 encoding sequence in one proband. The patient's KCN-affected sister harbored the same variation. The variation was not novel and was recently shown to be present at similar frequencies among large cohorts of KCN patients and control individuals. CONCLUSION: Mutations in MIR-184 are not a major cause of keratoconus among Iranian patients. The pri-miR-184 sequence needs to be screened in larger cohorts in order to establish whether mutations in the gene are present at low frequencies among Iranian patients.

Expression of pluripotent stem cell markers in mouse uterine tissue during estrous cycle.

It was assumed that uterine stem cells are responsible for the unique regenerative capacity of uterine. Therefore, the aim of the present study was to investigate the expression of the pluripotent stem cell markers in the mice uterine tissue during different stages of estrous cycles. Twelve virgin female NMRI mice (6 to 8 weeks old) were considered at proestrus, estrus, metestrus and diestrus according to the cell types observed in the vaginal smear and underwent hysterectomy operation. Quantitative real-time polymerase chain reaction (PCR) and immunohistochemical staining for pluripotent stem cell markers (SOX2, OCT4, KLF4, and NANOG) were performed. Immunofluorescence staining revealed that expression and localization of the pluripotency markers SOX2, OCT4, KLF4, and NANOG at the protein level were not different throughout estrous cycle. Also, mRNA of pluripotency markers was detected in all tested samples. However, there were no significant differences in their genes expression at each stage and during the estrous cycle. Different hormonal profile during the estrous cycle could not affect expression of pluripotent stem cell markers in uterine tissue.

Vitrification affects the expression of matrix metalloproteinases and their tissue inhibitors of mouse ovarian tissue.

BACKGROUND: One of the most major obstacles of ovarian tissue vitrification is suboptimal developmental competence of follicles. Matrix metalloproteinases 2 (MMP-2) and 9 (MMP-9) and their tissue inhibitors TIMP-1 and TIMP-2 are involved in the remodeling of the extracellular matrix in the ovaries. OBJECTIVE: This study aimed to evaluate the expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 genes in the preantral follicles derived from vitrified mouse ovaries. MATERIALS AND METHODS: In this experimental study, the gene expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 in the isolated preantral follicles derived from fresh and vitrified ovaries of 14-16 days old female mice through real time qRT-PCR was evaluated. Developmental parameters, including survival rate, growth, antrum formation and metaphase II oocytes were also analyzed. RESULTS: The developmental parameters of fresh preantral follicles were significantly higher than vitrified preantral follicles. The TIMP-1 and MMP-9 expression levels showed no differences between fresh and vitrified preantral follicles (p=0.22, p=0.11 respectively). By contrast, TIMP-2 expression significantly decreased (p=0.00) and MMP-2 expression increased significantly (p=0.00) in vitrified preantral follicles compared with to fresh ones. CONCLUSION: Changes in expression of MMP-2 and TIMP-2 after ovarian tissues vitrification is partially correlated with decrease in follicle development.

The effect of steroid hormones on the mRNA expression of oct4 and sox2 in uterine tissue of the ovariectomized mice model of menopause.

BACKGROUND: The uterus is a dynamic tissue responding to hormonal changes during reproductive cycles. As such, uterine stem cells have been studied in recent years. Transcription factors oct4 and sox2 are critical for effective maintenance of pluripotent cell identity. OBJECTIVE: The present research evaluated the mRNA expression of oct4 and sox2 in the uterine tissues of ovariectomized mice treated with steroid hormones. MATERIALS AND METHODS: In this experimental study, adult virgin female mice were ovariectomized and treated with estradiol 17ß (E2), progesterone (P4), and a combination of E2 and P4 (E2 & P4) for 5 days. Uterine tissues were removed, and immunofluorescent (IF) staining and quantitative real-time PCR of oct4 and sox2 markers were performed. RESULTS: IF showed oct4 and sox2 expression in the uterine endometrium and myometrium among all groups. The mRNA expression of oct4 (p=0.022) and sox2 (p=0.042) in the E2-treated group significantly were decreased compared to that in the control group. By contrast, the mRNA expression of oct4 and sox2 in the P4 (p=0.641 and 0.489 respectively) and E2 & P4-treated groups (p=0.267 and 0.264 respectively) did not show significant differences compared to the control group. CONCLUSION: The results indicate ovarian steroid hormones change the expression of oct4 and sox2 in the mice uterine tissues, which suggest the involvement of steroid hormonal regulation in uterine stem cells.

Comparing the Effect of Silybin and Silybin Advanced™ on Viability and HER2 Expression on the Human Breast Cancer SKBR3 Cell Line by no Serum Starvation.

The polyphenol silybin has anti-oxidant and anti-cancer properties. The poor bioavailability of some polyphenols (flavonoids, and terpenoids) can be improved by binding them to phosphatidylcholine (phytosome technology). Many studies have focused on the most common phytosome, silybin-phosphatidylcholine, particularly for its hepatoprotective effects. However, in recent years, studies have also been conducted to determine its anti-cancer effect. Considering that the serum starvation should not be used for studies that are not focused on cell cycle arrest, we studied the effect of silybin-phosphatidylcholine from Silybin Advanced™ in 1:2 ratio (one part silybin bound to two parts phosphatidylcholine) on HER2 gene expression on the SKBR3 breast cancer cell line which were cultured in complete medium (not serum deprivation). The results were compared with our previous study of silybin on HER2 expression on SKBR3 cells. An MTT test was used to determine concentrations for cell treatment, and the gene expression was defined by real-time RT-PCR. Outcomes showed significant concentration- and time-dependent cell growth inhibitory effects of silybin, and silybin-phosphatidylcholine and HER2 down regulation on SKBR3 cells. Silybin-phosphatidylcholine concentrations had a much larger inhibitory and HER2 down regulate effect on cell growth than the same silybin concentrations on SKBR3 cells.

The Comparison of The Effects of Silybin and Silybin-Phosphatidylcholine on Viability and ESR Expression in Human Breast Cancer T47D Cell Line.

OBJECTIVE: Silybin is a polyphenol with anti-oxidant and anti-cancer properties. The poor bioavailability of some polyphenols can be improved by binding to phosphatidylcholine. In recent years, studies have been conducted to evaluate the anti-cancer effect of silybin. We studied the effect of silybin and silybin-phosphatidylcholine on ESR1 and ESR2 gene expression and viability in the T47D breast cancer cell line. MATERIALS AND METHODS: In this experimental study, a 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide test (MTT test) was used to determine doses for cell treatment, and the gene expression was analyzed by real-time reverse transcriptase-polymerase chain reaction (real-time RT- PCR). RESULTS: Significant dose- and time-dependent cell growth inhibitory effects of silybin and silybin-phosphatidylcholine along with ESR1 down-regulation were observed in T47D cells. In contrast to ESR1, the T47D cell line showed negligible ESR2 expression. CONCLUSION: This study suggests that silybin and silybin-phosphatidylcholine down-regulate ESR1 in ER(+)breast cancers. Results also show that in the T47D cell line, silybindown-regulation of ESR1 compared with silybin.

Cyclic AMP pathway modifies memory through neural cell adhesion molecule alterations in the rat hippocampus.

Neural Cell Adhesion Molecules (NCAMs) are known to influence memory by affecting neural cell-cell and cell-extracellular matrix junctions. This study investigated the possible role of cAMP pathway in the expression of hippocampal NCAM and its polysialylated derivative (PSA-NCAM). The following pharmacological tools were employed for manipulation of cAMP pathway: a) forskolin; the activator of adenylyl cyclase (AC), b) 8-Br-cAMP; a protein kinase A (PKA) agonist, c) 8-pCPT-2'-O-Me-cAMP; a selective enhancer of exchange protein activated by cAMP (Epac) and d) Rp-cAMP; a PKA inhibitor. Memory acquisition was tested by passive avoidance paradigm after injecting the above compounds for three consecutive days into the CA1 region of dorsal hippocampus of rats. Forskolin and 8-Br-cAMP enhanced memory retrieval while Rp-cAMP significantly reduced memory and NCAM levels. 8-pCPT-2'-O-Me-cAMP failed to alter memory performance or NCAM levels as compared to vehicle. We observed no significant changes in PSA-NCAM, however the expression of St8sia4 and St8sia2 (the polysialyltransferase isoforms) were altered. The mRNA levels of St8sia4 was down-regulated by 8-Br-cAMP, Rp-cAMP and 8-pCPT while forskolin led to almost 3 and 5 fold increase in mRNAs of St8sia2 and St8sia4, respectively. The current insight might endorse the predominant role of PKA as compared to Epac in cAMP pathway in expression of NCAM and memory function.

A microRNA signature associated with chondrogenic lineage commitment.

Generating appropriate cartilage for clinical applications to heal skeletal tissue loss is a major health concern. In this regard, cell-based approaches offer a potential therapeutic strategy for cartilage repair, although little is known about the precise mechanism of chondrogenesis. Unrestricted somatic stem cell (USSC) is considered as a suitable candidate because of its potential for differentiating into multiple cell types. Recent studies show that microRNAs (miRNAs) are involved in several biological processes including development and differentiation. To identify the chondro-specific miRNA signature, miRNA patterns of USSCs and differentiated chondrocytes were investigated using microarrays and validation by qPCR. Prior to these analyses, chondrogenic commitment of differentiated USSCs was verified by immunocytochemistry, specific staining and evaluation of some main chondrogenic marker genes. Various in silico explorations (for both putative targets and signalling pathways) and empirical analyses (miRNA transfections followed by qPCR of some chondrogenic indicators) were carried out to support our results. Transient modulation of multiple chondro-miRs (such as mir-630, mir-624 and mir-376) with chondrocyte targets (such as TGFbR, MAP3K, collagens, SMADs and cadherins) as mediators of chondrogenic signalling pathways including cell-cell interactions, TGF-beta, and MAPK signalling suggests a mechanism for genetic induction of chondrogenic differentiation. In conclusion, this research reveals more details about the allocation of USSCs into the chondrocytes through identification of miRNA signature which modulates targets and pathways required for chondrogenic lineage and could provide guidelines for future clinical treatments and anti-miRNA therapies.