[Retracted] Hedgehog signaling is involved in the BMP9‑induced osteogenic differentiation of mesenchymal stem cells

Subsequently to the publication of the above paper, a concerned reader drew to the authors' attention that there were a number of overlapping data panels featured in the cellular images shown in Fig. 2C on p. 1644, and Figs. 3D and 4 on p. 1645, such that data that were allegedly obtained under different experimental conditions appeared to have been derived from some of the same original sources. Given the number of errors that had been made during the compilation of the figures in this article, the Editor of International Journal of Molecular Medicine has decided that this article should be retracted from the publication owing to a lack of overall confidence in the presented data. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience that might result from the retraction of this article. [International Journal of Molecular Medicine 35: 1641‑1650, 2015; DOI: 10.3892/ijmm.2015.2172].

Prophylactic Activation of Shh Signaling Attenuates TBI-Induced Seizures in Zebrafish by Modulating Glutamate Excitotoxicity through Eaat2a

Approximately 2 million individuals experience a traumatic brain injury (TBI) every year in the United States. Secondary injury begins within minutes after TBI, with alterations in cellular function and chemical signaling that contribute to excitotoxicity. Post-traumatic seizures (PTS) are experienced in an increasing number of TBI individuals that also display resistance to traditional anti-seizure medications (ASMs). Sonic hedgehog (Shh) is a signaling pathway that is upregulated following central nervous system damage in zebrafish and aids injury-induced regeneration. Using a modified Marmarou weight drop on adult zebrafish, we examined PTS following TBI and Shh modulation. We found that inhibiting Shh signaling by cyclopamine significantly increased PTS in TBI fish, prolonged the timeframe PTS was observed, and decreased survival across all TBI severities. Shh-inhibited TBI fish failed to respond to traditional ASMs, but were attenuated when treated with CNQX, which blocks ionotropic glutamate receptors. We found that the Smoothened agonist, purmorphamine, increased Eaat2a expression in undamaged brains compared to untreated controls, and purmorphamine treatment reduced glutamate excitotoxicity following TBI. Similarly, purmorphamine reduced PTS, edema, and cognitive deficits in TBI fish, while these pathologies were increased and/or prolonged in cyclopamine-treated TBI fish. However, the increased severity of TBI phenotypes with cyclopamine was reduced by cotreating fish with ceftriaxone, which induces Eaat2a expression. Collectively, these data suggest that Shh signaling induces Eaat2a expression and plays a role in regulating TBI-induced glutamate excitotoxicity and TBI sequelae.

[G-protein coupled receptor Smo positively regulates proliferation and migration of adult neural stem cells in vitro]

OBJECTIVE

To investigate the role of G-protein coupled receptor Smoothened (Smo) in regulating proliferation and migration of adult neural stem cells (ANSCs) and explore the underlying mechanism.

METHODS

Cultured ANSCs were treated with purmorphamine (PM, an agonist of Smo) or cyclopamine (CPM, an inhibitor of Smo), and the changes in cell proliferation migration abilities were assessed using cell counting kit-8 (CCK8) assay and wound healing assay, respectively. The mRNA expressions of membrane receptor Patched 1 (Ptch1), Smo, glioma-associated oncogene homolog 1 (Gli1), axon guidance cue slit1 (Slit1) and brain-derived neurotrophic factor (BDNF) in the treated cells were detected using real-time quantitative PCR (RT-PCR).

RESULTS

PM significantly promoted the proliferation (P < 0.01) and migration of ANSCs (P < 0.01), and up-regulated the mRNA expressions of Ptch1, Smo, Gli1, Slit1 and BDNF. Treatment with CPM significantly inhibited the proliferation and migration of ANSCs.

CONCLUSION

Modulating Smo activity can positively regulate the proliferation and migration of ANSCs possibly by regulating the expressions of BDNF and Slit1.

Ventral Telencephalic Patterning Protocols for Induced Pluripotent Stem Cells

The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer’s dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN. Ventralizing factors [i.e., purmorphamine and Sonic hedgehog (SHH)] were applied at different time points, time intervals, and concentrations. In addition, caudal identity was prevented by the use of a small molecule XAV-939 that inhibits the Wnt-pathway. After patterning, gene expression profiles were analyzed by quantitative PCR (qPCR). Rostro-ventral patterning is most effective when initiated simultaneously with neural induction. The most promising combination of patterning factors was 0.5 μM of purmorphamine and 1 μM of XAV-939, which induces the highest expression of transcription factors specific for the medial ganglionic eminence, the source of GABAergic inter- and cholinergic neurons in the telencephalon. Upon maturation of cells, the immune phenotype, as well as electrophysiological properties were investigated showing the presence of marker proteins specific for BFCN (choline acetyltransferase, ISL1, p75, and NKX2.1) and GABAergic neurons. Moreover, a considerable fraction of measured cells displayed mature electrophysiological properties. Synaptic boutons containing the vesicular acetylcholine transporter (VACHT) could be observed in the vicinity of the cells. This work will help to generate basal forebrain interneurons from hiPSCs, providing a promising platform for modeling neurological diseases, such as Alzheimer’s disease or Dystonia.

Growth factor mimetics for skin regeneration: In vitro profiling of primary human fibroblasts and keratinocytes

Small molecules have gained considerable interest in regenerative medicine, as they can effectively modulate cell fates in a spatiotemporal controllable fashion. A continuous challenge in the field represents genuine mimicry or activation of growth factor signaling with small molecules. Here, we selected and profiled three compounds for their capacity to directly or indirectly activate endogenous FGF-2, VEGF, or SHH signaling events in the context of skin regeneration. Phenotypic and functional analysis of primary skin fibroblasts and keratinocytes revealed unique, cell-specific activity profiles for the FGF-2 mimetic SUN11602 and the putative VEGF mimetic ONO-1301. Whereas SUN11602 exclusively stimulated keratinocyte differentiation, ONO-1301 mainly affected the proliferation and migration behavior of fibroblasts. In each skin cell type, both compounds selectively enhanced the expression of MMP1 and VEGFA. A combined small molecule FGF-2/VEGF mimicry may not only improve angiogenesis-related microcirculation but also reduce early fibrosis while facilitating wound remodeling at later stages. SUN11602 and ONO-1301 represent valuable tools for improving the management of difficult-to-heal wounds, particularly for the design and development of small molecule-functionalized, next-generation, engineered skin substitutes.

Smo-Shh signaling activator purmorphamine ameliorates neurobehavioral, molecular, and morphological alterations in an intracerebroventricular propionic acid-induced experimental model of autism

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disease characterized by cognitive and sensorimotor impairment. Numerous research findings have consistently shown that alteration of Smo-Shh (smoothened-sonic hedgehog) signaling during the developmental process plays a significant role in ASD and triggers neuronal changes by promoting neuroinflammation and apoptotic markers. Purmorphamine (PUR), a small purine-derived agonist of the Smo-Shh pathway, shows resistance to hippocampal neuronal cell oxidation and decreases neuronal cell death. The goal of this study was to investigate the neuroprotective potential of PUR in brain intoxication induced by intracerebroventricular-propionic acid (ICV-PPA) in rats, with a focus on its effect on Smo-Shh regulation in the brain of rats. In addition, we analyze the impact of PUR on myelin basic protein (MBP) and apoptotic markers such as Caspase-3, Bax (pro-apoptotic), and Bcl-2 (anti-apoptotic) in rat brain homogenates. Chronic ICV-PPA infusion was administered consecutively for 11 days to induce autism in rats. In order to investigate behavioral alterations, rats were tested for spatial learning in the Morris Water Maze (MWM), locomotive alterations using actophotometer, and beam crossing task, while Forced Swimming Test (FST) for depressive behavior. PUR treatment with 5 mg/kg and 10 mg/kg (i.p.) was administered from day 12 to 44. Besides cellular, molecular and neuroinflammatory analyses, neurotransmitter levels and oxidative markers have also been studied in brain homogenates. The results of this study have shown that PUR increases the level of Smo-Shh and restores the neurochemical levels, and potentially prevents morphological changes, including demyelination.

Purmorphamine Attenuates Neuro-Inflammation and Synaptic Impairments After Hypoxic-Ischemic Injury in Neonatal Mice via Shh Signaling

Purmorphamine (PUR), an agonist of the Smoothened (Smo) receptor, has been shown to function as a neuroprotectant in acute experimental ischemic stroke. Its role in hypoxic-ischemic (HI) brain injury in neonatal mice remains unknown. Here we show that PUR attenuated acute brain injury, with a decrease in Bax/Bcl-2 ratio as well as inhibition of caspase-3 activation. These beneficial effects of PUR were associated with suppressing neuro-inflammation and oxidative stress. PUR exerted long-term protective effects upon tissue loss and improved neurobehavioral outcomes as determined at 14 and 28 days post-HI insult. Moreover, PUR increased synaptophysin (Syn) and postsynaptic density (PSD) protein 95 expression in HI-treated mice and attenuated synaptic loss. PUR upregulated the expression of Shh pathway mediators, while suppression of the Shh signaling pathway with cyclopamine (Cyc) reversed these beneficial effects of PUR on HI insult. Our study suggests a therapeutic potential for short-term PUR administration in HI-induced injury as a result of its capacity to exert multiple protective actions upon acute brain injury, long-term memory deficits, and impaired synapses. Moreover, we provide evidence indicating that one of the mechanisms underlying these beneficial effects of PUR involves activation of the Shh signaling pathway.

Baihui (DU20)-penetrating-Qubin (GB7) acupuncture inhibits apoptosis in the perihemorrhagic penumbra

Baihui (DU20)-penetrating-Qubin (GB7) acupuncture can inhibit inflammatory reactions and activate signaling pathways related to proliferation after intracerebral hemorrhage. However, there is no research showing the relationship between this treatment and cell apoptosis. Rat models of intracerebral hemorrhage were established by injecting 60 μL of autologous blood into the right side of the caudate-putamen. Six hours later, the needle traveled subcutaneously from the Baihui acupoint to Qubin acupoint. The needle was alternately rotated (180 ± 10 turns/min) manually along clockwise and counter-clockwise directions. Stimulation lasted for 7 days, and was performed three times each for 6 minutes with 6-minute intervals between stimulations. Rats intraperitoneally receiving Sonic hedgehog pathway activator, purmorphamine (1 mg/kg per day), served as positive controls. Motor and sensory function were assessed using the Ludmila Belayev test. Extent of pathological changes were measured in the perihemorrhagic penumbra using hematoxylin-eosin staining. Apoptosis was examined by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling assay. Expression of smoothened (Smo) and glioma-associated homolog 1 (Gli1) was determined by western blot assay. Our results showed that Baihui-penetrating-Qubin acupuncture promoted recovery of motor and sensory function, reduced the apoptotic cell percentage in the perihemorrhagic penumbra, and up-regulated Smo and Gli1 expression. We conclude that Baihui-penetrating-Qubin acupuncture can mitigate hemorrhage and promote functional recovery of the brain in a rat model of intracerebral hemorrhage, possibly by activating the Sonic hedgehog pathway.

The Role of Hedgehog Signalling in the Formation of the Ventricular Septum

An incomplete septation of the ventricles in the vertebrate heart that disturbes the strict separation between the contents of the two ventricles is termed a ventricular septal defect (VSD). Together with bicuspid aortic valves, it is the most frequent congenital heart disease in humans. Until now, life-threatening VSDs are usually treated surgically. To avoid surgery and to develop an alternative therapy (e.g., a small molecule therapy), it is necessary to understand the molecular mechanisms underlying ventricular septum (VS) development. Consequently, various studies focus on the investigation of signalling pathways, which play essential roles in the formation of the VS. In the past decade, several reports found evidence for an involvement of Hedgehog (HH) signalling in VS development. In this review article, we will summarise the current knowledge about the association between HH signalling and VS formation and discuss the use of such knowledge to design treatment strategies against the development of VSDs.

Preconditioning potential of purmorphamine: a hedgehog activator against ischaemic reperfusion injury in ovariectomised rat heart

OBJECTIVE

The present study was been designed to investigate the role and pharmacological potential of hedgehog in oestrogen-deficient rat heart.

METHODS

Oestrogen deficiency was produced in female Wistar rats by the surgical removal of both ovaries and these animals were used four weeks later. Isolated rat heart was subjected to 30 min ischaemia followed by 120 min of reperfusion (I/R). The heart was subjected to pharmacological preconditioning with the hedgehog agonist purmorphamine (1μM) and GDC-0449, a hedgehog antagonist, in the last episode of reperfusion before I/R. Myocardial infarction was assessed in terms of the increase in lactate dehydrogenase (LDH), creatinine kinase-MB (CK-MB), myeloperoxidase (MPO) level and infarct size (triphenyltetrazolium chloride staining). Immunohistochemistry analysis was done for the assessment of tumour necrosis factor (TNF)-α level in cardiac tissue. eNOS expression was estimated by rt-PCR.

RESULTS

Pharmacological preconditioning with purmorphamine significantly attenuated I/R-induced myocardial infarction, TNF-α, MPO level and release of LDH and CK-MB compared to the I/R control group. However, GDC-0449 prevented the ameliorative preconditioning effect of estradiol.

CONCLUSION

It may be concluded that the hedgehog agonist purmorphamine prevents the ovariectomised heart from ischaemic reperfusion injury.

Neuroprotective Effects of a Smoothened Receptor Agonist against Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats

The sonic hedgehog (Shh) signaling pathway plays a fundamental role in the central nervous system (CNS) development, but its effects on neural cell survival and brain repair after subarachnoid hemorrhage (SAH) has not been well-investigated. The present study was undertaken to evaluate the influence of an agonist of the Shh co-receptor Smoothened (Smo), purmorphamine (PUR), on early brain injury (EBI) as well as the underlying mechanisms after SAH. PUR was administered via an intraperitoneal injection with a dose of 0.5, 1, and 5 mg/kg at 2, 6, 24, and 46 h after SAH in rat model. The results showed that PUR treatment significantly ameliorated brain edema, improved neurobehavioral function, and attenuated neuronal cell death in the prefrontal cortex (PFC), associated with a decrease in Bax/Bcl-2 ratio and suppression of caspase-3 activation at 48 h after SAH. PUR also promoted phospho-ERK levels. Additionally, PUR treatment markedly decreased MDA concentration accompanied with the elevation in the expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 in PFC. Notably, PUR treatment significantly reversed the changes of Shh pathway mediators containing Patched, Gli1, and Shh by SAH insult, and the neuroprotection of PUR on SAH was blocked by Smo antagonist cyclopamine. These results indicated that PUR exerts neuroprotection against SAH-evoked injury in rats, mediated in part by anti-apoptotic and anti-oxidant mechanism, up-regulating phospho-ERK levels, mediating Shh signaling molecules in the PFC.

Purmorphamine and oxysterols accelerate and promote osteogenic differentiation of mesenchymal stem cells in vitro

AIM

The purpose of the present study was to find inexpensive and non-toxic additives enhancing and accelerating the osteogenesis of mesenchymal stem cells in vitro, which can be used for tissue engineering of bone material.

MATERIALS AND METHODS

Osteogenic differentiation of rat mesenchymal stem cells was carried-out using classic differentiation medium containing or lacking purmorphamine, statins or oxysterols, respectively. Cell proliferation, alkaline phosphatase activity, calcium sedimentation and expression of bone matrix protein genes were measured to monitor differentiation.

RESULTS

Purmorphamine substantially suppressed proliferation, enhanced and accelerated alkaline phosphatase activity and calcium sedimentation and increased the expression of osteopontin and osteocalcin in rat mesenchymal stem cells in vitro. A similar osteogenesis-promoting effect was observed for oxysterols but not for the two statins.

CONCLUSION

Purmorphamine and oxysterols promote and accelerate osteogenesis of mesenchymal stem cells in vitro suggesting their potential application for tissue engineering of bone material.

Profiling metabolite changes in the neuronal differentiation of human striatal neural stem cells using 1H-magnetic resonance spectroscopy

OBJECTIVE

Neural stem cells (NSCs) have been found to play an increasing clinical role in stroke. However, at present, it is not yet possible to noninvasively monitor their differentiation once implanted into the brain.

METHODS

Here, we describe the use of high-resolution H-magnetic resonance spectroscopy (MRS) to define a metabolite profile of undifferentiated human striatal NSCs from the STROC05 cell line and their differentiation after 3-weeks of treatment with purmorphamine.

RESULTS

The undifferentiated conditions were characterized by ~95% of cells expressing nestin and ~77% being Ki67(+)ve, indicating that these were still proliferating. Phosphophocholine+glycerophosphocholine (PC+GPC) as well as myo-Inositol (mI) were increased in these cells. PC+GPC and mI were markedly reduced upon differentiation, potentially serving as markers of the NSC state. Upon differentiation (~45% neurons, ~30% astrocytes, ~13% oligodendrocytes), the concentration of many metabolites decreased in absolute value. The decreasing trend of the N-acetyl-aspartate level was observed in differentiated cells when compared with NSCs. An increase in plasmalogen (enriched in myelin sheets) could potentially serve as a marker of oligodendrocytes.

CONCLUSION

These metabolite characteristics of undifferentiated and differentiated NSCs provide a basis for exploration of their possible use as markers of differentiation after cell transplantation.