Effects of let-7b and TLX on the proliferation and differentiation of retinal progenitor cells in vitro

miR-124-3p regulates the proliferation and differentiation of retinal progenitor cells through SEPT10

Retinal degenerative diseases such as glaucoma, retinitis pigmentosa, and age-related macular degeneration pose serious threats to human visual health due to lack of effective therapeutic approaches. In recent years, the transplantation of retinal progenitor cells (RPCs) has shown increasing promise in the treatment of these diseases; however, the application of RPC transplantation is limited by both their poor proliferation and their differentiation capabilities. Previous studies have shown that microRNAs (miRNA) act as essential mediators in the fate determination of stem/progenitor cells. In this study, we hypothesized that miR-124-3p plays a regulatory role in the fate of RPC determination by targeting Septin10 (SEPT10) in vitro. We observed that the overexpression of miR124-3p downregulates SEPT10 expression in RPCs, leading to reduced RPC proliferation and increased differentiation, specifically towards both neurons and ganglion cells. Conversely, antisense knockdown of miR-124-3p was shown to boost SEPT10 expression, enhance RPC proliferation, and attenuate differentiation. Moreover, overexpression of SEPT10 rescued miR-124-3p-caused proliferation deficiency while weakening the enhancement of miR-124-3p-induced-RPC differentiation. Results from this study show that miR-124-3p regulates RPC proliferation and differentiation by targeting SEPT10. Furthermore, our findings enable a more comprehensive understanding into the mechanisms of proliferation and differentiation of RPC fate determination. Ultimately, this study may be useful for helping researchers and clinicians to develop more promising and effective approaches to optimize the use of RPCs in treating retinal degeneration diseases.

Induced retinal pigment epithelial cells with anti-epithelial-to-mesenchymal transition ability delay retinal degeneration

The hostile microenvironment of the retina in patients with age-related macular degeneration (AMD) may trigger epithelial-to-mesenchymal transition (EMT) of grafted retinal pigment epithelial (RPE) cells, thus attenuating the therapeutic outcome. Here, we transformed human dedifferentiated induced pluripotent stem cell-derived RPE (iPSC-RPE) cells into induced RPE (iRPE) cells using a cocktail of four transcription factors (TFs)-CRX, MITF-A, NR2E1, and C-MYC. These critical TFs maintained the epithelial property of iRPE cells by regulating the expression of bmp7, forkhead box f2, lin7a, and pard6b, and conferred resistance to TGF-β-induced EMT in iRPE cells by targeting ppm1a. The iRPE cells with Tet-on system-regulated c-myc expression exhibited EMT resistance and better therapeutic function compared with iPSC-RPE cells in rat AMD model. Our study demonstrates that endowing RPE cells with anti-EMT property avoids the risk of EMT after cells are grafted into the subretinal space, and it may provide a suitable candidate for AMD treatment.

miR-381-3p Cooperated With Hes1 to Regulate the Proliferation and Differentiation of Retinal Progenitor Cells

Retinal progenitor cells (RPCs) transplantation has become a promising therapy for retinal degeneration, which is a major kind of ocular diseases causing blindness. Since RPCs have limited proliferation and differentiation abilities toward retinal neurons, it is urgent to resolve these problems. MicroRNAs have been reported to have vital effects on stem cell fate. In our study, the data showed that overexpression of miR-381-3p repressed Hes1 expression, which promoted RPCs differentiation, especially toward neuronal cells, and inhibited RPCs proliferation. Knockdown of endogenous miR-381-3p increased Hes1 expression to inhibit RPCs differentiation and promote proliferation. In addition, a luciferase assay demonstrated that miR-381-3p directly targeted the Hes1 3’ untranslated region (UTR). Taken together, our study demonstrated that miR-381-3p regulated RPCs proliferation and differentiation by targeting Hes1, which provides an experimental basis of RPCs transplantation therapy for retinal degeneration.

Therapeutic effects of mesenchymal stem cells-derived extracellular vesicles' miRNAs on retinal regeneration: a review

Extracellular vesicles (EVs), which consist of microvesicles and exosomes, are secreted from all cells to transform vital information in the form of lipids, proteins, mRNAs and small RNAs such as microRNAs (miRNAs). Many studies demonstrated that EVs' miRNAs have effects on target cells. Numerous people suffer from the blindness caused by retinal degenerations. The death of retinal neurons is irreversible and creates permanent damage to the retina. In the absence of acceptable cures for retinal degenerative diseases, stem cells and their paracrine agents including EVs have become a promising therapeutic approach. Several studies showed that the therapeutic effects of stem cells are due to the miRNAs of their EVs. Considering the effects of microRNAs in retinal cells development and function and studies which provide the possible roles of mesenchymal stem cells-derived EVs miRNA content on retinal diseases, we focused on the similarities between these two groups of miRNAs that could be helpful for promoting new therapeutic techniques for retinal degenerative diseases.

Neuronal let-7b-5p acts through the Hippo-YAP pathway in neonatal encephalopathy

Despite increasing knowledge on microRNAs, their role in the pathogenesis of neonatal encephalopathy remains to be elucidated. Herein, we identify let-7b-5p as a significant microRNA in neonates with moderate to severe encephalopathy from dried blood spots using next generation sequencing. Validation studies using Reverse Transcription and quantitative Polymerase Chain Reaction on 45 neonates showed that let-7b-5p expression was increased on day 1 in neonates with moderate to severe encephalopathy with unfavourable outcome when compared to those with mild encephalopathy. Mechanistic studies performed on glucose deprived cell cultures and the cerebral cortex of two animal models of perinatal brain injury, namely hypoxic-ischaemic and intrauterine inflammation models confirm that let-7b-5p is associated with the apoptotic Hippo pathway. Significant reduction in neuronal let-7b-5p expression corresponded with activated Hippo pathway, with increased neuronal/nuclear ratio of Yes Associated Protein (YAP) and increased neuronal cleaved caspase-3 expression in both animal models. Similar results were noted for let-7b-5p and YAP expression in glucose-deprived cell cultures. Reduced nuclear YAP with decreased intracellular let-7b-5p correlated with neuronal apoptosis in conditions of metabolic stress. This finding of the Hippo-YAP association with let-7b needs validation in larger cohorts to further our knowledge on let-7b-5p as a biomarker for neonatal encephalopathy.

Using next generation sequencing of dried blood spots and subsequent validation, Ponnusamy et al identify let-7b-5p as an elevated microRNA in neonates with moderate to severe encephalopathy. Using cell culture and murine models of perinatal brain injury they demonstrate that the effects of let-7b-5p are elicited via the Hippo-YAP pathway, which should be validated in large neonate cohorts to expand our understanding of let-7b-5p as a biomarker for neonatal encephalopathy.

Retinal Degeneration: Short-Term Options and Long-Term Vision for Future Therapy

The leading cause blindness is the loss of retinal ganglion cells which connect the retina to the brain. Degenerative retinal diseases include retinal dystrophy, macular degeneration and diabetic retinopathy, which are currently incurable as the mammalian retina has no intrinsic regenerative capacity. By utilizing insight gained from retinal regeneration in simpler species we define an approach that may unlock regenerative programs in the mammalian retina that potentially facilitate the clinical restoration of retinal function.

Cathelicidin LL37 Promotes Osteogenic Differentiation in vitro and Bone Regeneration in vivo

Different types of biomaterials have been used to repair the defect of bony orbit. However, exposure and infections are still critical risks in clinical application. Biomaterials with characteristics of osteogenesis and antibiosis are needed for bone regeneration. In this study, we aimed to characterize the antimicrobial effects of cathelicidin-LL37 and to assess any impacts on osteogenic activity. Furthermore, we attempted to demonstrate the feasibility of LL37 as a potential strategy in the reconstruction of clinical bone defects. Human adipose-derived mesenchyme stem cells (hADSCs) were cultured with different concentrations of LL37 and the optimum concentration for osteogenesis was selected for further in vitro studies. We then evaluated the antibiotic properties of LL37 at the optimum osteogenic concentration. Finally, we estimated the efficiency of a PSeD/hADSCs/LL37 combined scaffold on reconstructing bone defects in the rat calvarial defect model. The osteogenic ability on hADSCs in vitro was shown to be dependent on the concentration of LL37 and reached a peak at 4 μg/ml. The optimum concentration of LL37 showed good antimicrobial properties against Escherichia coli and Staphylococcus anurans. The combination scaffold of PSeD/hADSCs/LL37 showed superior osteogenic properties compared to the PSeD/hADSCs, PSeD, and control groups scaffolds, indicating a strong bone reconstruction effect in the rat calvarial bone defect model. In Conclusion, LL37 was shown to promote osteogenic differentiation in vitro as well as antibacterial properties. The combination of PSeD/hADSCs/LL37 was advantageous in the rat calvarial defect reconstruction model, showing high potential in clinical bone regeneration.

let-7 miRNAs inhibit CHD7 expression and control auditory-sensory progenitor cell behavior in the developing inner ear

The evolutionarily conserved lethal-7 (let-7) microRNAs (miRNAs) are well-known activators of proliferative quiescence and terminal differentiation. However, in the murine auditory organ, let-7g overexpression delays the differentiation of mechano-sensory hair cells (HCs). To address whether the role of let-7 in auditory-sensory differentiation is conserved among vertebrates, we manipulated let-7 levels within the chicken auditory organ: the basilar papilla. Using a let-7 sponge construct to sequester let-7 miRNAs, we found that endogenous let-7 miRNAs are essential for limiting the self-renewal of HC progenitor cells. Furthermore, let-7b overexpression experiments revealed that, similar to mice, higher than normal let-7 levels slow/delay HC differentiation. Finally, we identify CHD7, a chromatin remodeler, as a candidate for mediating the repressive function of let-7 in HC differentiation and inner ear morphogenesis. Our analysis uncovered an evolutionarily conserved let-7-5p-binding site within the chicken Chd7 gene and its human and murine homologs, and we show that let-7g overexpression in mice limits CHD7 expression in the developing inner ear, retina and brain. Haploinsufficiency of CHD7 in humans causes CHARGE syndrome and attenuation of let-7 function may be an effective method for treating CHD7 deficiency.

miR-762 regulates the proliferation and differentiation of retinal progenitor cells by targeting NPDC1

Retinal degenerations, which lead to irreversible decline in visual function, are still no effective recovery treatments. Currently, retinal progenitor cell (RPC) transplantation therapy is expected to provide a new approach to treat these diseases; however, the limited proliferation capacity and differentiation potential toward specific retinal neurons of RPCs hinder their potential clinical applications. microRNAs have been reported to serve as important regulators in the cell fate determination of stem/progenitor cells. In this study, our data demonstrated that miR-762 inhibited NPDC1 expression to positively regulate RPC proliferation and suppress RPC neuronal differentiation. Furthermore, the knockdown of miR-762 upregulated NPDC1 expression in RPCs, leading to the inhibition of RPC proliferation and the increase in neuronal differentiation. Moreover, NPDC1 could rescue anti-miR-762-induced RPC proliferation deficiency and the inhibitory effect of miR-762 on RPC differentiation. In conclusion, our study demonstrated that miR-762 plays a crucial role in regulating RPC proliferation and differentiation by directly targeting NPDC1, which is firstly reported that microRNAs positively regulate RPC proliferation and negatively regulate RPC differentiation, which provides a comprehensive understanding of the molecular mechanisms that dominate RPC proliferation and differentiation in vitro.

A role for the orphan nuclear receptor TLX in the interaction between neural precursor cells and microglia

Microglia are an essential component of the neurogenic niche in the adult hippocampus and are involved in the control of neural precursor cell (NPC) proliferation, differentiation and the survival and integration of newborn neurons in hippocampal circuitry. Microglial and neuronal cross-talk is mediated in part by the chemokine fractalkine/chemokine (C-X3-C motif) ligand 1 (CX3CL1) released from neurons, and its receptor CX3C chemokine receptor 1 (CX3CR1) which is expressed on microglia. A disruption in this pathway has been associated with impaired neurogenesis yet the specific molecular mechanisms by which this interaction occurs remain unclear. The orphan nuclear receptor TLX (Nr2e1; homologue of the Drosophila tailless gene) is a key regulator of hippocampal neurogenesis, and we have shown that in its absence microglia exhibit a pro-inflammatory activation phenotype. However, it is unclear whether a disturbance in CX3CL1/CX3CR1 communication mediates an impairment in TLX-related pathways which may have subsequent effects on neurogenesis. To this end, we assessed miRNA expression of up- and down-stream signalling molecules of TLX in the hippocampus of mice lacking CX3CR1. Our results demonstrate that a lack of CX3CR1 is associated with altered expression of TLX and its downstream targets in the hippocampus without significantly affecting upstream regulators of TLX. Thus, TLX may be a potential participant in neural stem cell (NSC)-microglial cross-talk and may be an important target in understanding inflammatory-associated impairments in neurogenesis.

miR-17 regulates the proliferation and differentiation of retinal progenitor cells by targeting CHMP1A

MicroRNAs have a vital effect on the differentiation of many types of progenitor cells. Recent studies have suggested that miR-17 plays an important role in the differentiation process of brain neural progenitor cells (NPC). Nevertheless, its detailed functions in regulating retinal progenitor cells (RPC) remain unclear. In our study, overexpression and knockdown of miR-17 were performed by transfecting RPC with mimics and inhibitors, respectively. Next, we investigated the role of miR-17 in RPC proliferation and differentiation by the following experiments: qPCR, CCK8, Edu staining, immunostaining and Western blot. The results revealed that miR-17 inhibited RPC proliferation but enhanced differentiation. Furthermore, according to a web-based database analysis, we identified charged multivesicular body protein 1A (CHMP1A) as a target gene. A dual luciferase reporter system showed that miR-17 specifically binds to the CHMP1A 3' untranslated region (UTR). Next, our data showed upregulation of miR-17 decreased CHMP1A protein level, causing reduced proliferation and enhanced differentiation of RPC. Downregulation of miR-17 led to enhanced CHMP1A protein expression, increased RPC proliferation and decreased differentiation. Taken together, our data provide a proven pathway by which miR-17 regulates RPC proliferation and differentiation by targeting CHMP1A.

Cholesterol modification of SDF-1-specific siRNA enables therapeutic targeting of angiogenesis through Akt pathway inhibition

Neovascularization during ocular tissue repair can cause severe visual loss in the optical axis and is therefore an issue of considerable concern to ophthalmologists. Here, we introduced a cholesterol-modified siRNA delivery system targeting stromal cell-derived factor 1 (SDF-1) to treat ocular angiogenesis in vivo. SDF-1 expression was analyzed in rat endothelial progenitor cells (EPCs) and bone marrow mesenchymal stem cells (BMSCs) using quantitative PCR (qPCR). Migration ability of BMSC and HUVEC were assessed through transwell assay. The proliferation effect of chol-siSDF1 on HUVEC was measured by colony formation assay. In vivo anti-angiogenic effects of chol-siSDF1 were tested in a cornea alkali burn model and the area of cornea neovascularization was measured using computer-imaging analysis system. Then phosphorylated Akt and total Akt protein levels were measured through western blot. Results turned out that rat EPCs and BMSCs showed high SDF-1 mRNA expression, which can be down-regulated by using chol-siSDF-1. Chol-siSDF-1 could significantly inhibit migration of BMSC and HUVEC. In addition, chol-siSDF1 also could inhibit HUVEC proliferation and exert a significant anti-angiogenic effect in corneal alkali burn model. As for the mechanism, chol-siSDF1 may inhibit the neovascularization, proliferation and metastasis through inhibiting the Akt signaling pathway. Thus, cholesterol modification of siRNA targeting SDF-1 displays an effective inhibition of migration and angiogenesis, with a much longer duration of inhibition effect.

Choice of Alternative Polyadenylation Sites, Mediated by the RNA-Binding Protein Elavl3, Plays a Role in Differentiation of Inhibitory Neuronal Progenitors

Alternative polyadenylation (APA) is a widespread mechanism involving about half of the expressed genes, resulting in varying lengths of the 3′ untranslated region (3′UTR). Variations in length and sequence of the 3′UTR may underlie changes of post-transcriptional processing, localization, miRNA targeting and stability of mRNAs. During embryonic development a large array of mRNAs exhibit APA, with a prevalence of the longer 3′UTR versions in differentiating cells. Little is known about polyA+ site usage during differentiation of mammalian neural progenitors. Here we exploit a model of adherent neural stem (ANS) cells, which homogeneously and efficiently differentiate into GABAergic neurons. RNAseq data shows a global trend towards lengthening of the 3′UTRs during differentiation. Enriched expression of the longer 3′UTR variants of Pes1 and Gng2 was detected in the mouse brain in areas of cortical and subcortical neuronal differentiation, respectively, by two-probes fluorescent in situ hybridization (FISH). Among the coding genes upregulated during differentiation of ANS cells we found Elavl3, a neural-specific RNA-binding protein homologous to Drosophila Elav. In the insect, Elav regulates polyA+ site choice while interacting with paused Pol-II promoters. We tested the role of Elavl3 in ANS cells, by silencing Elavl3 and observed consistent changes in 3′UTR length and delayed neuronal differentiation. These results indicate that choice of the polyA+ site and lengthening of 3′UTRs is a possible additional mechanism of posttranscriptional RNA modification involved in neuronal differentiation.

Tubeimoside-1 inhibits the proliferation and metastasis by promoting miR-126-5p expression in non-small cell lung cancer cells

Tubeimoside-1 (TBMS1) possesses broad anticancer activities, including the cytostatic and anti-angiogenesis effects in lung cancer. However, the effect of TBMS1 on the metastasis of non-small cell lung cancer (NSCLC) cells and the potential underlying mechanism remain unclear. In the present study, a cell counting kit-8 assay revealed that TBMS1 suppressed the proliferation of NCI-H1299 cells significantly, particularly following 48 h of treatment. Further studies showed that TBMS1 notably enhanced the apoptosis, and inhibited the migration and invasion of NCI-H1299 cells upon treatment for 48 h. A total of 14 NSCLC tissues and 14 normal adjacent tissues were collected, reverse transcription-quantitative polymerase chain reaction revealed decreased expression of microRNA (miR)-126-5p in NSCLC tissues compared with adjacent NSCLC tissues, which was reversed following TBMS1 administration in NCI-H1299 cells. The overexpression of miR-126-5p induced by TBMS1 was demonstrated to target and downregulate vascular endothelial growth factor (VEGF)-A. Simultaneously, the expression of VEGF-R2 was reduced notably, along with a significant declined in the phosphorylation levels of dual specificity mitogen-activated protein kinase kinase 1 and extracellular signal-regulated kinase (ERK)1/2. Overall, the aforementioned results indicated that TBMS1 inhibited the proliferation and metastasis, and promoted the apoptosis of NCI-H1299 cells, which may be mediated by overexpressing miR-126-5p, which inactivates the VEGF-A/VEGFR2/ERK signaling pathway. Therefore, TBMS1 may be a promising drug for prevention and treatment of NSCLC.

Insulin-like growth factor-1 regulation of retinal progenitor cell proliferation and differentiation

Strategies to improve retinal progenitor cell (RPC) capacity to yield proliferative and multipotent pools of cells that can efficiently differentiate into retinal neurons, including photoreceptors, could be vital for cell therapy in retinal degenerative diseases. In this study, we found that insulin-like growth factor-1 (IGF-1) plays a role in the regulation of proliferation and differentiation of RPCs. Our results show that IGF-1 promotes RPC proliferation via IGF-1 receptors (IGF-1Rs), stimulating increased phosphorylation in the PI3K/Akt and MAPK/Erk pathways. An inhibitor experiment revealed that IGF-1-induced RPC proliferation was inhibited when the PI3K/Akt and MAPK/Erk pathways were blocked. Furthermore, under the condition of differentiation, IGF-1-pretreated RPCs prefer to differentiate into retinal neurons, including photoreceptors, in vitro, which is crucial for visual formation and visual restoration. These results demonstrate that IGF-1 accelerates the proliferation of RPCs and IGF-1 pretreated RPCs may have shown an increased potential for retinal neuron differentiation, providing a novel strategy for regulating the proliferation and differentiation of retinal progenitors in vitro and shedding light upon the application of RPCs in retinal cell therapy.

miR-29a regulates the proliferation and differentiation of retinal progenitors by targeting Rbm8a

During development, tight regulation of the expansion of retinal progenitor cells (RPCs) and their differentiation into neuronal and glial cells is important for retinal formation and function. Our study demonstrated that microRNA (miR)-29a modulated the proliferation and differentiation of RPCs by suppressing RBM8A (one of the factors in the exon junction complex). Particularly, overexpression of miR-29a reduced RPC proliferation but accelerated RPC differentiation. By contrast, reduction of endogenous miR-29a elicited the opposite effects. Overexpression of miR-29a repressed the translation of Rbm8a, thus negatively regulating RPC proliferation and promoting the neuronal and glial differentiation of RPCs, and knockdown of endogenous Rbm8a phenocopied the observed effects of miR-29a overexpression. Furthermore, a luciferase reporter assay showed that miR-29a directly interacted with the Rbm8a mRNA 3′UTR, which indicated that Rbm8a is the direct target of miR-29a. To further verify the result, co-overexpression of the Rbm8a 3′ UTR-wt (plasmids into which the Rbm8a 3′ UTR sequence had been introduced) and miR-29a in RPCs rescued the phenotype associated with miR-29a overexpression, reversing the promotion of differentiation and inhibition of proliferation. These results show a novel mechanism by which miR-29a regulates the proliferation and differentiation of RPCs through Rbm8a.

Nuclear receptors in neural stem/progenitor cell homeostasis

In the central nervous system, embryonic and adult neural stem/progenitor cells (NSCs) generate the enormous variety and huge numbers of neuronal and glial cells that provide structural and functional support in the brain and spinal cord. Over the last decades, nuclear receptors and their natural ligands have emerged as critical regulators of NSC homeostasis during embryonic development and adult life. Furthermore, substantial progress has been achieved towards elucidating the molecular mechanisms of nuclear receptors action in proliferative and differentiation capacities of NSCs. Aberrant expression or function of nuclear receptors in NSCs also contributes to the pathogenesis of various nervous system diseases. Here, we review recent advances in our understanding of the regulatory roles of steroid, non-steroid, and orphan nuclear receptors in NSC fate decisions. These studies establish nuclear receptors as key therapeutic targets in brain diseases.

Decellularized matrix of adipose-derived mesenchymal stromal cells enhanced retinal progenitor cell proliferation via the Akt/Erk pathway and neuronal differentiation

BACKGROUND AIMS

Retinal progenitor cells (RPCs) are a promising cell therapy treatment for retinal degenerative diseases. However, problems with limited proliferation ability and differentiation preference toward glia rather than neurons restrict the clinical application of these RPCs. The extracellular matrix (ECM) has been recognized to provide an appropriate microenvironment to support stem cell adhesion and direct cell behaviors, such as self-renewal and differentiation.

METHODS

In this study, decellularized matrix of adipose-derived mesenchymal stromal cells (DMA) was manufactured using a chemical agent method (0.5% ammonium hydroxide Triton + 20 mmol/L NH4OH) in combination with a biological agent method (DNase solution), and the resulting DMA were evaluated by scanning electron microscopy (SEM) and immunocytochemistry. The effect of DMA on RPC proliferation and differentiation was evaluated by quantitative polymerase chain reaction, Western blot and immunocytochemistry analysis.

RESULTS

DMA was successfully fabricated, as demonstrated by SEM and immunocytochemistry. Compared with tissue culture plates, DMA may effectively enhance the proliferation of RPCs by activating Akt and Erk phosphorylation; when the two pathways were blocked, the promoting effect was reversed. Moreover, DMA promoted the differentiation of RPCs toward retinal neurons, especially rhodopsin- and recoverin-positive photoreceptors, which is the most interesting class of cells for retinal degeneration treatment.

CONCLUSIONS

These results indicate that DMA has important roles in governing RPC proliferation and differentiation and may contribute to the application of RPCs in treating retinal degenerative diseases.

Betacellulin regulates the proliferation and differentiation of retinal progenitor cells in vitro

Retinal progenitor cells (RPCs) hold great potential for the treatment of retinal degenerative diseases. However, their proliferation capacity and differentiation potential towards specific retinal neurons are limited, which limit their future clinical applications. Thus, it is important to improve the RPCs’ ability to proliferate and differentiate. Currently, epidermal growth factor (EGF) is commonly used to stimulate RPC growth in vitro. In this study, we find that betacellulin (BTC), a member of the EGF family, plays important roles in the proliferation and differentiation of RPCs. Our results showed that BTC can significantly promote the proliferation of RPCs more efficiently than EGF. EGF stimulated RPC proliferation through the EGFR/ErbB2‐Erk pathway, while BTC stimulated RPC proliferation more powerfully through the EGFR/ErbB2/ErbB4‐Akt/Erk pathway. Meanwhile, under differentiated conditions, the BTC‐pre‐treated RPCs were preferentially differentiated into retinal neurons, including photoreceptors, one of the most important types of cells for retinal cell replacement therapy, compared to the EGF‐pre‐treated RPCs. In addition, knockdown of endogenous BTC expression can also obviously promote RPC differentiation into retinal neuronal cells. This data demonstrate that BTC plays important roles in promoting RPC proliferation and differentiation into retinal neurons. This study may provide new insights into the study of RPC proliferation and differentiation and make a step towards the application of RPCs in the treatment of retinal degenerative diseases.

Developmental pathway genes and neural plasticity underlying emotional learning and stress-related disorders

The manipulation of neural plasticity as a means of intervening in the onset and progression of stress-related disorders retains its appeal for many researchers, despite our limited success in translating such interventions from the laboratory to the clinic. Given the challenges of identifying individual genetic variants that confer increased risk for illnesses like depression and post-traumatic stress disorder, some have turned their attention instead to focusing on so-called "master regulators" of plasticity that may provide a means of controlling these potentially impaired processes in psychiatric illnesses. The mammalian homolog of Tailless (TLX), Wnt, and the homeoprotein Otx2 have all been proposed to constitute master regulators of different forms of plasticity which have, in turn, each been implicated in learning and stress-related disorders. In the present review, we provide an overview of the changing distribution of these genes and their roles both during development and in the adult brain. We further discuss how their distinct expression profiles provide clues as to their function, and may inform their suitability as candidate drug targets in the treatment of psychiatric disorders.

Functional integration of complex miRNA networks in central and peripheral lesion and axonal regeneration

New players are emerging in the game of peripheral and central nervous system injury since their physiopathological mechanisms remain partially elusive. These mechanisms are characterized by several molecules whose activation and/or modification following a trauma is often controlled at transcriptional level. In this scenario, microRNAs (miRNAs/miRs) have been identified as main actors in coordinating important molecular pathways in nerve or spinal cord injury (SCI). miRNAs are small non-coding RNAs whose functionality at network level is now emerging as a new level of complexity. Indeed they can act as an organized network to provide a precise control of several biological processes. Here we describe the functional synergy of some miRNAs in case of SCI and peripheral damage. In particular we show how several small RNAs can cooperate in influencing simultaneously the molecular pathways orchestrating axon regeneration, inflammation, apoptosis and remyelination. We report about the networks for which miRNA-target bindings have been experimentally demonstrated or inferred based on target prediction data: in both cases, the connection between one miRNA and its downstream pathway is derived from a validated observation or is predicted from the literature. Hence, we discuss the importance of miRNAs in some pathological processes focusing on their functional structure as participating in a cooperative and/or convergence network.

Progress of stem/progenitor cell-based therapy for retinal degeneration

Retinal degeneration (RD), such as age-related macular degeneration (AMD) and retinitis pigmentosa, is one of the leading causes of blindness. Presently, no satisfactory therapeutic options are available for these diseases principally because the retina and retinal pigmented epithelium (RPE) do not regenerate, although wet AMD can be prevented from further progression by anti-vascular endothelial growth factor therapy. Nevertheless, stem/progenitor cell approaches exhibit enormous potential for RD treatment using strategies mainly aimed at the rescue and replacement of photoreceptors and RPE. The sources of stem/progenitor cells are classified into two broad categories in this review, which are (1) ocular-derived progenitor cells, such as retinal progenitor cells, and (2) non-ocular-derived stem cells, including embryonic stem cells, induced pluripotent stem cells, and mesenchymal stromal cells. Here, we discuss in detail the progress in the study of four predominant stem/progenitor cell types used in animal models of RD. A short overview of clinical trials involving the stem/progenitor cells is also presented. Currently, stem/progenitor cell therapies for RD still have some drawbacks such as inhibited proliferation and/or differentiation in vitro (with the exception of the RPE) and limited long-term survival and function of grafts in vivo. Despite these challenges, stem/progenitor cells represent the most promising strategy for RD treatment in the near future.

Poly (fumaroyl bioxirane) maleate: A potential functional scaffold for bone regeneration

Proper scaffolds combined with mesenchymal stem cells (MSCs) represent a promising strategy for repairing bone defects. In a previous study, poly (fumaroyl bioxirane) maleate (PFM), a newly developed functional polymer with numerous functional groups, exhibited excellent biocompatibility and enhanced the alkaline phosphatase (ALP) activity of osteoblasts in vitro. Here, to provide further and comprehensive insight into the application of PFM in bone tissue engineering, we investigated the osteoinductive potential of PFM cultured with rat adipose-derived mesenchymal stem cells (rADSCs). The results showed that PFM resulted in greater proliferation of rADSCs and that the PFM substrate had stronger osteoinductivity than PLGA and the control, as indicated by the significant upregulation of osteogenesis-related genes, proteins and calcium mineralization in vitro. Next, PFM was combined with rADSCs to repair a critical-sized calvarial defect in rats. Compared to the PLGA scaffold, the PFM scaffold significantly promoted new bone formation and exhibited excellent effects in repairing rat calvarial defects. In conclusion, PFM possesses strong osteoinductivity, which could markedly enhance bone regeneration, suggesting that PFM could serve as a promising and effective optimization method for traditional scaffolds in bone regeneration.

Effects of miR-146a on the osteogenesis of adipose-derived mesenchymal stem cells and bone regeneration

Increasing evidence has indicated that bone morphogenetic protein 2 (BMP2) coordinates with microRNAs (miRNAs) to form intracellular networks regulating mesenchymal stem cells (MSCs) osteogenesis. This study aimed to identify specific miRNAs in rat adipose-derived mesenchymal stem cells (ADSCs) during BMP2-induced osteogenesis, we selected the most significantly down-regulated miRNA, miR-146a, to systematically investigate its role in regulating osteogenesis and bone regeneration. Overexpressing miR-146a notably repressed ADSC osteogenesis, whereas knocking down miR-146a greatly promoted this process. Drosophila mothers against decapentaplegic protein 4 (SMAD4), an important co-activator in the BMP signaling pathway, was miR-146a’s direct target and miR-146a exerted its repressive effect on SMAD4 through interacting with 3′-untranslated region (3′-UTR) of SMAD4 mRNA. Furthermore, knocking down SMAD4 attenuated the ability of miR-146a inhibitor to promote ADSC osteogenesis. Next, transduced ADSCs were incorporated with poly(sebacoyl diglyceride) (PSeD) porous scaffolds for repairing critical-sized cranial defect, the treatment of miR-146a inhibitor greatly enhanced ADSC-mediated bone regeneration with higher expression levels of SMAD4, Runt-related transcription factor 2 (Runx2) and Osterix in newly formed bone. In summary, our study showed that miR-146a negatively regulates the osteogenesis and bone regeneration from ADSCs both in vitro and in vivo.

Electrospun silk fibroin/poly(lactide-co-ε-caprolactone) nanofibrous scaffolds for bone regeneration

Background

Tissue engineering has become a promising therapeutic approach for bone regeneration. Nanofibrous scaffolds have attracted great interest mainly due to their structural similarity to natural extracellular matrix (ECM). Poly(lactide-co-ε-caprolactone) (PLCL) has been successfully used in bone regeneration, but PLCL polymers are inert and lack natural cell recognition sites, and the surface of PLCL scaffold is hydrophobic. Silk fibroin (SF) is a kind of natural polymer with inherent bioactivity, and supports mesenchymal stem cell attachment, osteogenesis, and ECM deposition. Therefore, we fabricated hybrid nanofibrous scaffolds by adding different weight ratios of SF to PLCL in order to find a scaffold with improved properties for bone regeneration.

Methods

Hybrid nanofibrous scaffolds were fabricated by blending different weight ratios of SF with PLCL. Human adipose-derived stem cells (hADSCs) were seeded on SF/PLCL nanofibrous scaffolds of various ratios for a systematic evaluation of cell adhesion, proliferation, cytotoxicity, and osteogenic differentiation; the efficacy of the composite of hADSCs and scaffolds in repairing critical-sized calvarial defects in rats was investigated.

Results

The SF/PLCL (50/50) scaffold exhibited favorable tensile strength, surface roughness, and hydrophilicity, which facilitated cell adhesion and proliferation. Moreover, the SF/PLCL (50/50) scaffold promoted the osteogenic differentiation of hADSCs by elevating the expression levels of osteogenic marker genes such as BSP, Ocn, Col1A1, and OPN and enhanced ECM mineralization. In vivo assays showed that SF/PLCL (50/50) scaffold improved the repair of the critical-sized calvarial defect in rats, resulting in increased bone volume, higher trabecular number, enhanced bone mineral density, and increased new bone areas, compared with the pure PLCL scaffold.

Conclusion

The SF/PLCL (50/50) nanofibrous scaffold facilitated hADSC proliferation and osteogenic differentiation in vitro and further promoted new bone formation in vivo, suggesting that the SF/PLCL (50/50) nanofibrous scaffold holds great potential in bone tissue regeneration.

Effects of corneal stromal cell- and bone marrow-derived endothelial progenitor cell-conditioned media on the proliferation of corneal endothelial cells

AIM

To explore the effects of conditioned media on the proliferation of corneal endothelial cells (CECs) and to compare the efficiency of different conditioned media (CM).

METHODS

Rat CECs, corneal stromal cells (CSCs), bone marrow-derived endothelial progenitor cells (BEPCs), and bone marrow-derived mesenchymal stem cells (BMSCs) were isolated and cultured in vitro. CM was collected from CSCs, BEPCs, and BMSCs. CECs were cultivated in different culture media. Cell morphology was recorded, and gene and protein expression were analyzed.

RESULTS

After grown in CM for 5d, CECs in each experimental group remained polygonal, in a cobblestone-like monolayer arrangement. Immunocytofluorescence revealed positive expression of Na(+)/K(+)-ATP, aquaporin 1 (AQP1), and zonula occludens 1 (ZO-1). Based on quantitative polymerase chain reaction (qPCR) analysis, Na(+)/K(+)-ATP expression in CSC-CM was notably upregulated by 1.3-fold (±0.036) (P<0.05, n=3). The expression levels of ZO-1, neuron specific enolase (NSE), Vimentin, paired homebox 6 (PAX6), and procollagen type VIII (COL8A1) were notably upregulated in each experimental group. Each CM had a positive effect on CEC proliferation, and CSC-CM had the strongest effect on proliferation.

CONCLUSION

CSC-CM, BEPC-CM, and BMSC-CM not only stimulated the proliferation of CECs, but also maintained the characteristic differentiated phenotypes necessary for endothelial functions. CSC-CM had the most notable effect on CEC proliferation.

Rs895819 within miR-27a might be involved in development of non small cell lung cancer in the Chinese Han population

MicroRNA-27a (miR-27a) is deemed to be an oncogene that plays an important role in development of various cancers, and single nucleotide polymorphism (SNP) of miR-27a can influence the maturation or aberrant expression of hsa-miR27a, resulting in increased risk of cancer and poor prognosis for non-small cell lung cancer (NSCLC). This study aimed to assess the effects of rs895819 within miR-27a on susceptibility and prognosis of NSCLC patients in 560 clinical confirmed cases and 568 healthy check-up individuals. Adjusted odds/hazard ratios (ORs/HRs) and 95% confidential intervals (CIs) were calculated to evaluate the association between rs895819 and the risk and prognosis of NSCLC. The results showed that allele A and genotype GG of rs895819 were significantly associated with an increased risk of NSCLC (38.9% vs 30.8%, adjusted OR=1.26, 95%CI=1.23-1.29 for allele G vs A; 18.1% vs 11.7%, adjusted OR=1.67, 95%CI=1.59-1.75 for genotype GG vs AA). Moreover, positive associations were also observed in dominant and recessive models (53.7% vs 49.9%, adjusted OR=1.17, 95%CI=1.13-1.20 for GG/AG vs AA; 18.1% vs 11.7%, adjusted=1.65, 95%CI=1.58-1.73). However, no significant association was found between rs895819 and the prognosis of NSCLC in genotype, dominant and recessive models. These results suggested that miR-27a might be involved in NSCLC carcinogenesis, but not in progression of NSCLC. The allele G, genotype GG and allele G carrier (GG/AG vs AA) of rs895819 might be genetic susceptible factors for NSCLC. Further multi-central, large sample size and well-designed prospective studies as well as functional studies are warranted to verify our findings.

Nr2e1 Deficiency Augments Palmitate-Induced Oxidative Stress in Beta Cells

Nuclear receptor subfamily 2 group E member 1 (Nr2e1) has been regarded as an essential regulator of the growth of neural stem cells. However, its function elsewhere is unknown. In the present study, we generated Nr2e1 knockdown MIN6 cells and studied whether Nr2e1 knockdown affected basal beta cell functions such as proliferation, cell death, and insulin secretion. We showed that knockdown of Nr2e1 in MIN6 cells resulted in increased sensitivity to lipotoxicity, decreased proliferation, a partial G0/G1 cell-cycle arrest, and higher rates of apoptosis. Moreover, Nr2e1 deficiency exaggerates palmitate-induced impairment in insulin secretion. At the molecular level, Nr2e1 deficiency augments palmitate-induced oxidative stress. Nr2e1 deficiency also resulted in decreases in antioxidant enzymes and expression level of Nrf2. Together, this study indicated a potential protective effect of Nr2e1 on beta cells, which may serve as a target for the development of novel therapies for diabetes.

A regulatory loop containing miR-26a, GSK3β and C/EBPα regulates the osteogenesis of human adipose-derived mesenchymal stem cells

Elucidating the molecular mechanisms responsible for osteogenesis of human adipose-derived mesenchymal stem cells (hADSCs) will provide deeper insights into the regulatory mechanisms of this process and help develop more efficient methods for cell-based therapies. In this study, we analysed the role of miR-26a in the regulation of hADSC osteogenesis. The endogenous expression of miR-26a increased during the osteogenic differentiation. The overexpression of miR-26a promoted hADSC osteogenesis, whereas osteogenesis was repressed by miR-26a knockdown. Additionally, miR-26a directly targeted the 3′UTR of the GSK3β, suppressing the expression of GSK3β protein. Similar to the effect of overexpressing miR-26a, the knockdown of GSK3β promoted osteogenic differentiation, whereas GSK3β overexpression inhibited this process, suggesting that GSK3β acted as a negative regulator of hADSC osteogenesis. Furthermore, GSK3β influences Wnt signalling pathway by regulating β-catenin, and subsequently altered the expression of its downstream target C/EBPα. In turn, C/EBPα transcriptionally regulated the expression of miR-26a by physically binding to the CTDSPL promoter region. Taken together, our data identified a novel feedback regulatory circuitry composed of miR-26a, GSK3β and C/EBPα, the function of which might contribute to the regulation of hADSC osteogenesis. Our findings provided new insights into the function of miR-26a and the mechanisms underlying osteogenesis of hADSCs.

Electrospun SF/PLCL nanofibrous membrane: a potential scaffold for retinal progenitor cell proliferation and differentiation

Biocompatible polymer scaffolds are promising as potential carriers for the delivery of retinal progenitor cells (RPCs) in cell replacement therapy for the repair of damaged or diseased retinas. The primary goal of the present study was to investigate the effects of blended electrospun nanofibrous membranes of silk fibroin (SF) and poly(L-lactic acid-co-ε-caprolactone) (PLCL), a novel scaffold, on the biological behaviour of RPCs in vitro. To assess the cell-scaffold interaction, RPCs were cultured on SF/PLCL scaffolds for indicated durations. Our data revealed that all the SF/PLCL scaffolds were thoroughly cytocompatible, and the SF:PLCL (1:1) scaffolds yielded the best RPC growth. The in vitro proliferation assays showed that RPCs proliferated more quickly on the SF:PLCL (1:1) than on the other scaffolds and the control. Quantitative polymerase chain reaction (qPCR) and immunocytochemistry analyses demonstrated that RPCs grown on the SF:PLCL (1:1) scaffolds preferentially differentiated toward retinal neurons, including, most interestingly, photoreceptors. In summary, we demonstrated that the SF:PLCL (1:1) scaffolds can not only markedly promote RPC proliferation with cytocompatibility for RPC growth but also robustly enhance RPCs’ differentiation toward specific retinal neurons of interest in vitro, suggesting that SF:PLCL (1:1) scaffolds may have potential applications in retinal cell replacement therapy in the future.

Reconstruction of conjunctival epithelium-like tissue using a temperature-responsive culture dish

PURPOSE

To study the feasibility of engineering conjunctival epithelial cell sheets on a temperature-responsive culture dish for ocular surface reconstruction.

METHODS

Rabbit conjunctival epithelial cells (rCjECs) were cultured in DMEM/F-12 (1:1) medium. The morphology and phenotype of the rCjECs were confirmed with phalloidin staining, periodic acid-Schiff (PAS) staining, and immunocytochemistry. The rCjECs cultured on a temperature-responsive culture dish for 10 days produced confluent conjunctival epithelial cell sheets. Then, the phenotype, structure, and function of the conjunctival epithelial cell sheets were examined.

RESULTS

The conjunctival epithelial cells were compact, uniform, and cobblestone shape. All cultured conjunctival epithelial cells were harvested as intact cell sheets by reducing the culture temperature to 20 °C. Conjunctival epithelial cells were stratified in four to five cell layers similar to the conjunctival epithelium. CCK-8 analysis, 5-bromo-2'-deoxyuridine (BrdU) staining, and the live and dead viability assay confirmed that viable proliferation cells were retained in the cell sheets. Immunohistochemistry for CK4, CK19, and MUC5AC showed the cell sheets still maintained characteristics of the conjunctival epithelium.

CONCLUSIONS

A temperature-responsive culture dish enables fabrication of viable conjunctival epithelial cell sheets with goblet cells and proliferative cells. Conjunctival epithelial cell sheets will be promising for reconstruction of the conjunctival epithelium.

MicroRNA-378 regulates neural stem cell proliferation and differentiation in vitro by modulating Tailless expression

Previous studies have suggested that microRNAs (miRNAs) play an important role in regulating neural stem cell (NSC) proliferation and differentiation. However, the precise role of miRNAs in NSC remains largely unexplored. In this study, we showed that miR-378 can target Tailless (TLX), a critical regulator of NSC, to regulate NSC proliferation and differentiation. By bioinformatic algorithms, miR-378 was found to have a predicted target site in the 3'-untranslated region of TLX, which was verified by a dual-luciferase reporter assay. The expression of miR-378 was increased during NSC differentiation and inversely correlated with TLX expression. qPCR and Western blot analysis also showed that miR-378 negatively regulated TLX mRNA and protein expression in neural stem cells (NSCs). Intriguingly, overexpression of miR-378 increased NSC differentiation and reduced NSC proliferation, whereas suppression of miR-378 led to decreased NSC differentiation and increased NSC proliferation. Moreover, the downstream targets of TLX, including p21, PTEN and Wnt/β-catenin were also found to be regulated by miR-378. Additionally, overexpression of TLX rescued the NSC proliferation deficiency induced by miR-378 overexpression and abolished miR-378-promoted NSC differentiation. Taken together, our data suggest that miR-378 is a novel miRNA that regulates NSC proliferation and differentiation via targeting TLX. Therefore, manipulating miR-378 in NSCs could be a novel strategy to develop novel interventions for the treatment of relevant neurological disorders.

Noncoding RNAs and the control of signalling via nuclear receptor regulation in health and disease

Nuclear receptors belong to a superfamily of proteins that play central roles in human biology, orchestrating a large variety of biological functions in both health and disease. Understanding the interactions and regulatory pathways of NRs will allow development of potential therapeutic interventions for a multitude of disease processes. Non-coding RNAs have recently been discovered to have significant interactions with NR signalling pathways via a variety of biological connections. This review summarises the known interactions between ncRNAs and the NR superfamily in health, embryogenesis and a plethora of human diseases.

Characterization of human ethmoid sinus mucosa derived mesenchymal stem cells (hESMSCs) and the application of hESMSCs cell sheets in bone regeneration

Mesenchymal stem cells (MSCs) have been extensively applied in the field of tissue regeneration. MSCs derived from various tissues exhibit different characteristics. In this study, a cluster of cells were isolated from human ethmoid sinus mucosa membrane and termed as hESMSCs. hESMSCs was demonstrated to have MSC-specific characteristics of self-renewal and tri-lineage differentiation. In particular, hESMSCs displayed strong osteogenic differentiation potential, and also remarkably promoted the proliferation and osteogenesis of rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. Next, hESMSCs were prepared into a cell sheet and combined with a PSeD scaffold seeded with rBMSCs to repair critical-sized calvarial defects in rats, which showed excellent reparative effects. Additionally, ELISA assays revealed that secreted cytokines, such as BMP-2, BMP-4 and bFGF, were higher in the hESMSCs conditioned medium, and immunohistochemistry validated that hESMSCs cell sheet promoted the expression of BMP signaling downstream genes in newly formed bone. In conclusion, hESMSCs were demonstrated to be a class of mesenchymal stem cells that possessed high self-renewal capacity along with strong osteogenic potential, and the cell sheet of hESMSCs could remarkably promote new bone regeneration, indicating that hESMSCs cell sheet could serve as a novel and promising alternative strategy in the management of bone regeneration.