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| PUR attenuated SAH-induced neurological deficits and brain edema. (A) Neurological scores were recorded at 48 h after SAH, n = 15. (B) Brain water content of cerebral cortex was measured at 48 h after SAH, n = 6. Values represent the mean ± SD. **p < 0.01, ***p < 0.001 SAH vs. Sham, # p < 0.05, ## p < 0.01 SAH+PUR vs. SAH, & p < 0.05 SAH+PUR+Cyc vs. SAH+PUR.
Source publication
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 (...
Citations
... 11 In addition, studies have shown that upregulation of the SHH signalling pathway can improve the prognosis of SAH. 12 However, it is not clear whether oestrogen can ameliorate BBB damage after SAH through the SHH pathway. ...
Background
Sex differences affect the occurrence, progression and regression of subarachnoid haemorrhage (SAH). Oestrogen plays a protective role in alleviating the vasospasm and neuronal apoptosis induced by SAH. However, whether oestrogen affects blood‒brain barrier (BBB) integrity has not been fully studied. Oestrogen has been found to regulate the sonic hedgehog (SHH) signalling pathway through the oestrogen receptor in gastric cancer and adrenal glands, and the SHH signalling pathway has an important role in maintaining the BBB by upregulating the expression of tight junction proteins. In this study, we investigated the relationship between oestrogen and the SHH signalling pathway using clinical data and established an experimental SAH model to explore whether oestrogen could ameliorate BBB damage after SAH through the SHH pathway.
Methods
Correlations between oestrogen and the SHH pathway were analysed by patients’ cerebrospinal fluid (CSF) samples and the Genotype-Tissue Expression database (GTEx). Then, an experimental rat SAH model was established using the endovascular perforation method and treated with oestrogen, oestrogen inhibitors and SHH signalling pathway inhibitors. Then, the effects of oestrogen on BBB damage were analysed by western blot, immunofluorescence and neurobehavioural experiments.
Results
ESLIA detection and correlation analysis showed that oestrogen levels in patients’ CSF were positively correlated with the SHH pathway, which was further verified by GTEx gene-correlation analysis. SHH was found to be mainly expressed in neurons and astrocytes in rats under physiological conditions and was upregulated by oestrogen pretreatment. In the SAH model, oestrogen pretreatment was found to reverse SAH-induced decreases in the SHH pathway, which were counteracted by oestrogen receptor inhibitors. Furthermore, oestrogen pretreatment reduced SAH-induced BBB damage, brain oedema and neurological dysfunction, which were eliminated by SHH pathway inhibitors.
Conclusion
In conclusion, we demonstrate here that oestrogen pretreatment ameliorates brain injury after SAH, at least in part through SHH pathway-mediated BBB protection.
... Purmorphamine (PUR) (15 mg/kg) activates SHH signaling pathway by binding and activating the SMO protein [12,13,37,38]. Cyclopamine (CYC) (12 mg/kg) [39,40] is an inhibitor of the SHH signaling pathway. ...
The Sonic Hedgehog (SHH) signaling pathway is related to the progression of various tumors and nervous system diseases. Still, its specific role in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), remains studied. This research investigates the role of SHH and PI3K/AKT signaling pathway proteins on ALS development in a SOD1-G93A transgenic mouse model. After injection of SHH and PI3K/AKT signaling pathway inhibitors or agonists in hSOD1-G93A (9 weeks of age) transgenic mice, we studied skeletal muscle pathology using immunohistochemical staining and Western blot methods. In addition, recorded data on rotation time, weight, and survival were analyzed for these mice. Our study showed that the expression of SHH, Gli-1 and p-AKT in ALS mice decreased with the progression of the disease. The expression of p-AKT changed together with Gli-1 while injecting PI3K/AKT signaling pathway inhibitor or agonist; SHH and Gli-1 protein expression remained unchanged; p-AKT protein expression significantly decreased while injecting PI3K/AKT signaling pathway inhibitor. These results indicate that SHH has a regulatory effect on PI3K/AKT signaling pathway. In behavioral experiments, we found that the survival time of hSOD1-G93A mice was prolonged by injection of SHH agonist while shortened by injection of SHH inhibitor. In conclusion, we confirmed that the SHH pathway played a neuroprotective role in ALS by mediating PI3K/AKT signaling pathway.
... Recent studies have demonstrated that nuclear factor 2 (Nrf2) is the core transcription factor of antioxidant response of exogenous stimuli. Under the conditions of oxidative stress, Nrf2 goes through the cytoplasm and enters the nucleus, which regulates the expression of cytoprotective enzymes such as nicotinamide adenine dinucleotide phosphate quinone oxidoreductase 1 (NrQO1) and glutathione s-transferase (GST), thus reducing cell oxidation and inflammation (77). Oxidative stress causes endoplasmic reticulum (ER) stress which disrupts protective signals thus leading to glycogen synthase kinase 3 beta (GSK-3β) phosphorylation and increasing in mitochondrial GSK-3β. ...
Background
To critically evaluate the neurological recovery effects and antioxidant effects of erythropoietin (EPO) in rat models of spinal cord injury (SCI).
Methods
The PubMed, EMBASE, MEDLINE, ScienceDirect, and Web of Science were searched for animal experiments applying EPO to treat SCI to January 2022. We included studies which examined neurological function by the Basso, Beattie, and Bresnahan (BBB) scale, as well as cavity area and spared area, and determining the molecular-biological analysis of antioxidative effects by malondialdehyde (MDA) levels in spinal cord tissues. Meta-analysis were performed with Review Manager 5.4 software.
Results
A total of 33 studies were included in this review. The results of the meta-analysis showed that SCI rats receiving EPO therapy showed a significant locomotor function recovery after 14 days compared with control, then the superiority of EPO therapy maintained to 28 days from BBB scale. Compared with the control group, the cavity area was reduced [4 studies, weighted mean difference (WMD) = −16.65, 95% CI (−30.74 to −2.55), P = 0.02] and spared area was increased [3 studies, WMD =11.53, 95% CI (1.34 to 21.72), P = 0.03] by EPO. Meanwhile, MDA levels [2 studies, WMD = −0.63 (−1.09 to −0.18), P = 0.007] were improved in the EPO treatment group compared with control, which indicated its antioxidant effect. The subgroup analysis recommended 5,000 UI/kg is the most effective dose [WMD = 4.05 (2.23, 5.88), P < 0.0001], although its effect was not statistically different from that of 1,000 UI/kg. Meanwhile, the different rat strains (Sprague-Dawley vs. Wistar), and models of animals, as well as administration method (single or multiple administration) of EPO did not affect the neuroprotective effect of EPO for SCI.
Conclusions
This systematic review indicated that EPO can promote the recovery of the locomotor function of SCI rats. The mechanism exploration of EPO needs to be verified by experiments, and then carefully designed randomized controlled trials are needed to explore its neural recovery effects.
... Exploration of the capacity to induce HH signaling in neurodegenerative disease models to facilitate functional recovery. Studies have supported neuroprotective and regenerative activities following sufficient stimulation of the HH pathway in conditions ranging from PD (Shao et al. 2017) to ALS (Peterson and Turnbull 2012) to hemorrhage (Hu et al. 2017). PD is a severe neurological disorder characterized by the destruction of the dopaminergic neurons of the nigra substance. ...
Autism is a multifactorial neurodevelopmental condition; it demonstrates some main characteristics, such as impaired social relationships and increased repetitive behavior. The initiation of autism spectrum disorder is mostly triggered during brain development by the deregulation of signaling pathways. Sonic hedgehog (SHH) signaling is one such mechanism that influences neurogenesis and neural processes during the development of the central nervous system. SMO-SHH signaling is also an important part of a broad variety of neurological processes, including neuronal cell differentiation, proliferation, and survival. Dysregulation of SMO-SHH signaling leads to many physiological changes that lead to neurological disorders such as ASD and contribute to cognitive decline. The aberrant downregulation of SMO-SHH signals contributes to the proteolytic cleavage of GLI (glioma-associated homolog) into GLI3 (repressor), which increases oxidative stress, neuronal excitotoxicity, neuroinflammation, and apoptosis by suppressing target gene expression. We outlined in this review that SMO-SHH deregulation plays a crucial role in the pathogenesis of autism and addresses the current status of SMO-SHH pathway modulators. Additionally, a greater understanding of the SHH signaling pathway is an effort to improve successful treatment for autism and other neurological disorders. This is a preview of subscription content, log in to check access. Access options
... It was shown that following TBI in zebrafish and rodents, genes encoding Shh signaling components were upregulated as early as 6 h post-injury (hpi) [17,36]. Additionally, Shh activation attenuated sequelae following various forms of CNS trauma [23,[37][38][39]. We examined undamaged and TBI fish that were either untreated or treated with the Smo antagonist cyclopamine (a Shh signaling inhibitor) at 4, 12, 24, 36, and 48 hpi. ...
... Purmorphamine treatment has also been shown to improve the neurobehavioral and cognitive recovery following CNS trauma [23,[37][38][39]. Zebrafish was previously shown to have a significant learning and memory impairment following sTBI, which rapidly recovered in 4-7 dpi [17,28]. ...
... For example, in epileptic rodents, Feng et al. [70] reported that increased Shh expression exacerbated seizure activity and negatively regulated extracellular glutamate, while others reported data suggesting that Shh activity upregulated EAAT2 expression, reduced astrocyte reactivity, and combated excitotoxicity [45,46,71,72]. Other studies reported that Shh activation is neuroprotective [23,[37][38][39] and is effective in regenerative therapies [35,73,74]. However, much work needs to be done to provide insights into the mechanistic actions contributing these positive neurological outcomes. ...
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.
... Further, it promotes the transcription factor "Glioma-associated oncogene" (Gli) translocating to the nucleus and regulating the target gene's transcription and expression. 17,18 Shh plays an essential role in the forebrain's growth, hindbrain, spinal cord and proliferation, differentiation, and axonal targeting. 19 Shh pathway also activates during adult brain injuries, neurodegenerative disorders, and neurogenesis. ...
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.
... 33 In an adult stroke model, Shh administration increased microvessel density and EC number 7 days after MCAO, 13 while Smo agonist cyclopamine blocked neuroprotective effects in early subarachnoid hemorrhage. 34 In our model of neonatal tMCAO, SAG administration promoted OPC numbers and angiogenesis. We found newly generated ECs in the injured core coupled with increased vascular branching after SAG treatment, suggesting enhanced vascular remodeling. ...
Background
Neonatal stroke affects 1 in 2800 live births and is a major cause of neurological injury. The Sonic hedgehog (Shh) signaling pathway is critical for central nervous system (CNS) development and has neuroprotective and reparative effects in different CNS injury models. Previous studies have demonstrated beneficial effects of small molecule Shh-Smoothened agonist (SAG) against neonatal cerebellar injury and it improves Down syndrome-related brain structural deficits in mice. Here we investigated SAG neuroprotection in rat models of neonatal ischemia–reperfusion (stroke) and adult focal white matter injury.
Methods
We used transient middle cerebral artery occlusion at P10 and ethidium bromide (EB) injection in adult rats to induce damage. Following surgery and SAG or vehicle treatment, we analyzed tissue loss, cell proliferation and fate, and behavioral outcome.
Results
We report that a single dose of SAG administered following neonatal stroke preserved brain volume, reduced gliosis, enhanced oligodendrocyte progenitor cell (OPC) and EC proliferation, and resulted in long-term cognitive improvement. Single-dose SAG also promoted proliferation of OPCs following focal demyelination in the adult rat.
Conclusions
These findings indicate benefit of one-time SAG treatment post insult in reducing brain injury and improving behavioral outcome after experimental neonatal stroke.
Impact
A one-time dose of small molecule Sonic hedgehog agonist protected against neonatal stroke and improved long-term behavioral outcomes in a rat model.
This study extends the use of Sonic hedgehog in treating developing brain injury, previously shown in animal models of Down syndrome and cerebellar injury.
Sonic hedgehog agonist is one of the most promising therapies in treating neonatal stroke thanks to its safety profile and low dosage.
... The SHH pathway is a critical signaling pathway in a variety of diseases, such as asthma, gastrointestinal system, preeclampsia, bladder cancer, and brain injury (Wang et al., 2008(Wang et al., , 2019Amankulor et al., 2009;Sims et al., 2009;Syed et al., 2016;Hu et al., 2017;Qi et al., 2018;Liao et al., 2019). The potential biological mechanisms of the SHH signaling pathway in CNS may be associated with a wide range of pathological processes, such as neurogenesis, anti-oxidation, autophagy, and antiapoptosis. ...
Background : Intracerebral hemorrhage (ICH) is a fatal subtype of stroke that lacks effective therapy. Blood-brain barrier (BBB) damage is a hallmark of ICH-induced brain injury that leads to edema formation, leukocytes infiltration, influx of blood components into the perihematomal (PHE) region, and eventually brain injury. Astrocytes are essential for the formation and maintenance of the BBB by providing secreted molecules that contribute to the association between these cells. Sonic hedgehog (SHH) derived from astrocytes promotes the maturity and integrity of the BBB by upregulating tight junctions (TJs) in brain capillary endothelial cells (ECs). However, the effect of SHH on BBB in ICH has not been investigated.
Methods : Cyclopamine (CYC) is a potent, selective inhibitor that specifically blocks the SHH signaling pathway. Here, we used pharmacological inhibitions (CYC and its derivatives) to determine a critical role of the SHH signaling pathway in promoting BBB integrity after ICH by mechanisms of regulating the TJ proteins in vivo and in vitro .
Results : The expression of astrocytic SHH was upregulated in mouse brains after ICH. Compared with the vehicle-treated group, inhibition of the SHH signaling pathway with CYC and its derivatives treatments aggravated neurological function deficits, brain edema, hematoma volume, and BBB impairment by downregulating TJs in ECs through the SHH-Gli-1 axis in vivo and in vitro .
Conclusions : SHH signaling pathway at the level of the BBB provides a barrier-promoting effect, suggesting that the SHH signaling pathway may function as a potential therapeutic target for restoring BBB function in ICH.
... PUR, which has also been shown to promote blood-brain barrier formation, plays a crucial role in activation of the endogenous anti-inflammatory system within the CNS [9], and recent findings have indicated that PUR protects cortical neurons and restores neurological deficits after ischemic stroke in rats [10]. It has been reported by us that PUR exerted neuroprotection against subarachnoid hemorrhage-induced injury in adult rats [11] and hypoxia-ischemia in neonatal mice [12]. ...
... There is one report showing that expressions of Shh, Gli-1, and Ptch1 protein were all upregulated in cortical neurons at 6 h after MACO injury in rats [10], while others have reported that Gli1 and Ptch1 expressions were upregulated at 6, 12, 24, and 48 h postischemic injury [20]. However, a downregulation of Shh expression within the cortex has also been reported in the early stages after experimental subarachnoid hemorrhage [11,21] and hypoxia-ischemia in neonatal mice [12]. In the present study, we found that neuronal expressions of Shh and Gli-1 were increased in the early stages of OGD insult, while the expressions of Shh, Gli-1, and Ptch were decreased at later time points following OGD. ...
Cerebral ischemia is a common cerebrovascular condition which often induces neuronal apoptosis, leading to brain damage. The sonic hedgehog (Shh) signaling pathway has been reported to be involved in ischemic stroke, but the underlying mechanisms have not been fully elucidated. In the present study, we demonstrated that expressions of Shh, Ptch, and Gli-1 were significantly downregulated at 24 h following oxygen-glucose deprivation (OGD) injury in neurons in vitro, effects which were associated with increasing numbers of apoptotic cells and reactive oxygen species generation. In addition, expressions of synaptic proteins (neuroligin and neurexin) were significantly downregulated at 8 h following OGD, also associated with concomitant neuronal apoptosis. Treatment with purmorphamine, a Shh agonist, increased Gli-1 in the nucleus of neurons and protected against OGD injury, whereas the Shh inhibitor, cyclopamine, produced the opposite effects. Activation of Shh signals promoted CREB and Akt phosphorylation; upregulated the expressions of BDNF, neuroligin, and neurexin; and decreased NF-κB phosphorylation following OGD. Notably, this activation of Shh signals was accompanied by improved neurobehavioral responses along with attenuations in edema and apoptosis at 48 h postischemic insult in rats. Taken together, these results demonstrate that activation of the Shh signaling pathway played a neuroprotective role in response to ischemic exposure via promotion of synaptic and neuronal health.
... For pharmacological activation of Hh signaling in mice, PM was diluted in a vehicle solution consisting of 2% DMSO, 30% PEG 300 and 5% Tween 80, and subcutaneously injected to mice in low-and high-PM groups in the center of the calvariae at a dosage of 2.5 mg/kg and 10 mg/kg, respectively. The PM dosage of 10 mg/kg used in this study was converted from a dose of 5 mg/kg previously used in rats based on relative body surface area of rats and mice [43,44]. As control, the same amount of vehicle solution was given to mice in sham and vehicle groups. ...
Rationale: Wear particle-induced periprosthetic osteolysis (PPO) is a common long-term complication of total joint arthroplasty, and represents the major cause of aseptic loosening and subsequent implant failure. Previous studies have identified the central role of osteoclast-mediated bone resorption in the pathogenesis of PPO. Thus, therapeutic approaches of inhibiting osteoclast formation and activity are considered to be of great potential to prevent and treat this osteolytic disease. Hedgehog (Hh) signaling has been shown to play an important role in promoting osteoblast differentiation and bone formation. While Hh signaling is also implicated in regulating osteoclastogenesis, whether it can directly inhibit osteoclast differentiation and bone resorption remains controversial. Moreover, its potential therapeutic effects on PPO have never been assessed. In this study, we explored the cell-autonomous role of Hh signaling in regulating osteoclastogenesis and its therapeutic potential in preventing wear particle-induced osteolysis.
Methods: Hh signaling was activated in macrophages by genetically ablating Sufu in these cells using LysM-Cre or by treating them with purmorphamine (PM), a pharmacological activator of Smoothened (Smo). In vitro cell-autonomous effects of Hh pathway activation on RANKL-induced osteoclast differentiation and activity were evaluated by TRAP staining, phalloidin staining, qPCR analyses, and bone resorption assays. In vivo evaluation of its therapeutic efficacy against PPO was performed in a murine calvarial model of titanium particle-induced osteolysis by μCT and histological analyses. Mechanistic details were explored in RANKL-treated macrophages through Western blot analyses.
Results: We found that Sufu deletion or PM treatment potently activated Hh signaling in macrophages, and strongly inhibited RANKL-induced TRAP⁺ osteoclast production, F-actin ring formation, osteoclast-specific gene expression, and osteoclast activity in vitro. Furthermore, we found that Sufu deletion or PM administration significantly attenuated titanium particle-induced osteoclast formation and bone loss in vivo. Our mechanistic study revealed that activation of Hh signaling suppressed RANKL-induced activation of JNK pathway and downregulated protein levels of two key osteoclastic transcriptional factors, c-Fos and its downstream target NFATc1.
Conclusions: Both genetic and pharmacological activation of Hh signaling can cell-autonomously inhibit RANKL-induced osteoclast differentiation and activity in vitro and protect against titanium particle-induced osteolysis in vivo. Mechanistically, Hh signaling hinders osteoclastogenesis partly through suppressing the JNK/c-Fos-NFATc1 cascade. Thus, Hh signaling may serve as a promising therapeutic target for the prevention and treatment of PPO and other osteolytic diseases.
