bFGF inhibits ER stress induced by ischemic oxidative injury via activation of the PI3K/Akt and ERK1/2 pathways

PI3K/AKT pathway: A potential therapeutic target in cerebral ischemia-reperfusion injury

Cerebral ischemia is a prevalent cerebrovascular disorder, with the restoration of blocked blood vessels serving as the current standard clinical treatment. However, reperfusion can exacerbate neuronal damage and neurological dysfunction, resulting in cerebral ischemia-reperfusion (I/R) injury. Presently, clinical treatment strategies for cerebral I/R injury are limited, creating an urgent need to identify new effective therapeutic targets. The PI3K/AKT signaling pathway, a pro-survival pathway associated with cerebral I/R injury, has garnered significant attention. We conducted a comprehensive review of the literature on the PI3K/AKT pathway in the context of cerebral I/R. Our findings indicate that activation of the PI3K/AKT signaling pathway following cerebral I/R can alleviate oxidative stress, reduce endoplasmic reticulum stress (ERS), inhibit inflammatory responses, decrease neuronal apoptosis, autophagy, and pyroptosis, mitigate blood-brain barrier (BBB) damage, and promote neurological function recovery. Consequently, this pathway ultimately reduces neuronal death, alleviates brain tissue damage, decreases the volume of cerebral infarction, and improves behavioral impairments. These results suggest that the PI3K/AKT signaling pathway is a promising therapeutic target for further research and drug development, holding significant potential for the treatment of cerebral I/R injury.

Hypoxia Regulates the Proliferation and Apoptosis of Coronary Artery Smooth Muscle Cells Through HIF-1α Mediated Autophagy in Yak

Cell proliferation and migration mediated by hypoxia-inducible factor-1α (HIF-1α) are important processes of hypoxic cardiac vascular remodeling. HIF-1α also regulates the physiological hypoxic adaptation of the coronary artery in the yak heart, but the potential mechanism remains to be completely elucidated. In this study, coronary artery proliferation increased with age and hypoxia adaptation time. In vitro analysis showed that hypoxia can promote the proliferation of coronary vascular smooth muscle cells (CASMCs). Meanwhile, HIF-1α plays an important role in the regulation of proliferation and migration under hypoxia. Autophagy regulates cell proliferation and migration to participate in hypoxia adaptation in plateau animals. Here, the level of autophagy increased significantly in yak coronary arteries with age and was regulated by HIF-1α-mediated hypoxia. In addition, autophagy could also mediate the hypoxic effect on the proliferation and migration of CASMCs. In summary, the results revealed that the increase in yak heart coronary artery thickening with age increases vascular smooth muscle cell proliferation and migration, mainly achieved through hypoxia-mediated HIF-1α-regulated autophagy. These results contribute to understanding how the heart adapts to life in a hypoxic environment.

Shikonin Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis to Attenuate Renal Ischemia/Reperfusion Injury by Activating the Sirt1/Nrf2/HO-1 Pathway

INTRODUCTION

Shikonin is the major bioactive compound abundant in Lithospermum erythrorhizon and possesses diverse pharmacological properties. This study aimed to examine shikonin roles in experimental renal ischemia/reperfusion (I/R) injury.

METHODS

Renal tissues and blood were collected from experimental renal I/R injury models. Kidney functions, structural injuries, and cellular death were assessed. Markers of endoplasmic reticulum (ER) stress were evaluated by RT-qPCR and Western blotting. The effect of shikonin on Sirt1/Nrf2/HO-1 signaling was detected by Western blotting and immunofluorescence staining. HK-2 cells that underwent hypoxia/reoxygenation (H/R) process were used to perform CCK-8 and flow cytometry.

RESULTS

For in vivo analysis, renal dysfunctions and tissue structural damage induced by I/R were relieved by shikonin. Additionally, shikonin alleviated ER stress-induced apoptosis in I/R mice. For in vitro analysis, shikonin inhibited ER stress-stimulated apoptosis of H/R cells. Mechanistically, shikonin activated Sirt1/Nrf2/HO-1 signaling post-I/R, and inhibition of Sirt1 limited shikonin-mediated protection against ER stress-stimulated apoptosis in both animal and cellular models.

CONCLUSION

By activating Sirt1/Nrf2/HO-1 signaling, shikonin inhibits apoptosis caused by ER stress and relieves renal I/R injury.

Exploring allocryptopine as a neuroprotective agent against oxidative stress-induced neural apoptosis via Akt/GSK-3β/tau pathway modulation

Alzheimer's disease (AD) is characterized by neuronal loss due to hyperphosphorylated proteins induced by oxidative stress. AD remains a formidable challenge in the medical field, as current treatments focusing on single biomarkers have yielded limited success. Hence, there's a burgeoning interest in investigating novel compounds that can target mechanisms, offering alternative therapeutic approaches. The aim of this study is to investigate the effects of allocryptopine, an isoquinoline alkaloid, on mechanisms related to AD in order to develop alternative treatment strategies. In this study, the in vitro AD cell model was obtained by inducing nerve growth factor (NGF)-differentiated PC12 (dPC12) cells to oxidative stress with H2O2, and also the effect mechanism of different allocryptopine concentrations on the in vitro AD cell model was studied. The treatments' antioxidative effects at the ROS level and their regulation of the cell cycle were assessed through flow cytometry, while their anti-apoptotic effects were evaluated using both flow cytometry and qRT-PCR. Additionally, the phosphorylation levels of Akt, GSK-3β, and tau proteins were analyzed via western blot, and the interactions between Akt, GSK-3β, CDK5 proteins, and allocryptopine were demonstrated through molecular docking. Our study's conclusive results revealed that allocryptopine effectively suppressed intracellular ROS levels, while simultaneously enhancing the Akt/GSK-3β signaling pathway by increasing p-Akt and p-GSK-3β proteins. This mechanism played a critical role in inhibiting neural cell apoptosis and preventing tau hyperphosphorylation. Moreover, allocryptopine demonstrated its ability to regulate the G1/S cell cycle progression, leading to cell cycle arrest in the G1 phase, and facilitating cellular repair mechanisms, potentially contributing to the suppression of neural apoptosis. The in silico results of allocryptopine were shown to docking with the cyclin-dependent kinase 5 (CDK 5) playing a role in tau phosphorylation Akt and GSK-3β from target proteins. Therefore, the in silico study results supported the in vitro results. The results showed that allocryptopine can protect dPC12 cells from oxidative stress-induced apoptosis and hyperphosphorylation of the tau protein by regulating the Akt/GSK-3β signaling pathway. Based on these findings, it can be suggested that allocryptopine, with its ability to target biomarkers and its significant effects on AD-associated mechanisms, holds promise as a potential candidate for drug development in the treatment of AD. Further research and clinical trials are recommended in the future.

Neuroprotective Effects of Intermittent Fasting in the Aging Brain

BACKGROUND

A major risk factor for neurodegenerative disorders is old age. Nutritional interventions that delay aging, such as calorie restriction (CR) and intermittent fasting (IF), as well as pharmaceuticals that affect the pathways linking nutrition and aging processes, have been developed in recent decades and have been shown to alleviate the effects of aging on the brain.

SUMMARY

CR is accomplished by alternating periods of ad libitum feeding and fasting. In animal models, IF has been shown to increase lifespan and slow the progression and severity of age-related pathologies such as cardiovascular and neurodegenerative diseases and cancer. According to recent research, dietary changes can help older people with dementia retain brain function. However, the mechanisms underlying the neuroprotective effect of IF on the aging brain and related questions in this area of study (i.e., the potential of IF to treat neurodegenerative disorders) remain to be examined.

KEY MESSAGES

This review addresses the hypothesis that IF may have translational potential in protecting the aged brain while summarizing the research supporting the putative neuroprotective mechanisms of IF in animal models. Additionally, given the emerging understanding of the connection between aging and dementia, our investigations may offer a fresh perspective on the use of dietary interventions for enhancing brain function and preventing dementia in elderly individuals. Finally, the absence of guidelines regarding the application of IF in patients hampers its broad utilization in clinical practice, and further studies are needed to improve our knowledge of the long-term effects of IF on dementia before it can be widely prescribed. In conclusion, IF may be an ancillary intervention for preserving memory and cognition in elderly individuals.

Cross-talk between bioactive lipid mediators and the unfolded protein response in ischemic stroke

Ischemic cerebral stroke is a severe medical condition that affects about 15 million people every year and is the second leading cause of death and disability globally. Ischemic stroke results in neuronal cell death and neurological impairment. Current therapies may not adequately address the deleterious metabolic changes and may increase neurological damage. Oxygen and nutrient depletion along with the tissue damage result in endoplasmic reticulum (ER) stress, including the Unfolded Protein Response (UPR), and neuroinflammation in the affected area and cause cell death in the lesion core. The spatio-temporal production of lipid mediators, either pro-inflammatory or pro-resolving, decides the course and outcome of stroke. The modulation of the UPR as well as the resolution of inflammation promotes post-stroke cellular viability and neuroprotection. However, studies about the interplay between the UPR and bioactive lipid mediators remain elusive and this review gives insights about the crosstalk between lipid mediators and the UPR in ischemic stroke. Overall, the treatment of ischemic stroke is often inadequate due to lack of effective drugs, thus, this review will provide novel therapeutical strategies that could promote the functional recovery from ischemic stroke.

Comparison of angiogenic potential in vitrified vs. slow frozen human ovarian tissue

Vitrification of ovarian tissue is a promising alternative approach to the traditional slow freezing method. Few empirical investigations have been conducted to determine the angiogenic profiles of these two freezing methods. In this study we aimed to answer the question whether one of the cryopreservation methods should be preferred based on the secretion of angiogenic factors. Tissue culture with reduced oxygen (5%) was conducted for 48 h with samples of fresh, slow frozen/thawed and vitrified/rapid warmed ovarian cortex tissue from 20 patients. From each patient, tissue was used in all three treatment groups. Tissue culture supernatants were determined regarding cytokine expression profiles of angiogenin, angiopoietin-2, epidermal growth factor, basic fibroblast growth factor, heparin binding epidermal growth factor, hepatocyte growth factor, Leptin, Platelet-derived growth factor B, placental growth factor and vascular endothelial growth factor A via fluoroimmunoassay. Apoptotic changes were assessed by TUNEL staining of cryosections and supplemented by hematoxylin and eosin and proliferating cell nuclear antigen staining. Comparing the angiogenic expression profiles of vitrified/rapid warmed tissue with slow frozen/thawed tissue samples, no significant differences were observed. Detection of apoptotic DNA fragmentation via TUNEL indicated minor apoptotic profiles that were not significantly different comparing both cryopreservation methods. Vitrification of ovarian cortical tissue does not appear to impact negatively on the expression profile of angiogenic factors and may be regarded as an effective alternative approach to the traditional slow freezing method.

Evaluating the effect of basic fibroblast growth factor on the progression of NASH disease by inhibiting ceramide synthesis and ER stress-related pathways

Non-alcoholic steatohepatitis (NASH) is associated with intrahepatic lipid accumulation, inflammation, and hepatocyte death. Several studies have indicated that high-fat diets increase ceramide synthases-6 (CerS-6) expression and a concomitant elevation of C16-ceramides, which can modulate endoplasmic reticulum (ER) stress and further contribute to the progression of NASH. Ceramide levels have reportedly been impacted by basic fibroblast growth factor (bFGF) in various diseases. This study looked into the role of bFGF on CerS6/C16-ceramide and ER stress-related pathways in a mouse model of NASH. Male C57BL/6J mice were fed a western diet (WD) combined with carbon tetrachloride (CCl4) for eight weeks. Next, bFGF was injected into the NASH mice for seven days of continuous treatment. The effects of bFGF on NASH endpoints (including steatosis, inflammation, ballooning, and fibrosis), ceramide levels and ER-stress-induced inflammation, reactive oxygen species (ROS) production, and apoptosis were evaluated. Treatment with bFGF significantly reduced CerS-6/C16-ceramide. Further, the inflammatory condition was alleviated with reduction of nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) gene expression. ROS level was also reduced. ER stress-related cell death diminished by reducing C/EBP homologous protein (CHOP) mRNA expression and caspase 3 activity. Furthermore, activation of the hepatic stellate cells was inhibited in the bFGF-treated mice by lowering the amount of alpha-smooth muscle actin (α-SMA) at the mRNA and protein level. According to our findings, CerS-6/C16-ceramide alteration impacts ER stress-mediated inflammation, oxidative stress, and apoptosis. The bFGF treatment effectively attenuated the development of NASH by downregulating CerS-6/C16-ceramide and subsequent ER stress-related pathways.

MiR-342-5p protects neurons from cerebral ischemia induced-apoptosis through regulation of Akt/NF-κB pathways by targeting CCAR2

OBJECTIVES

Ischemic stroke causes high morbidity, mortality and health burden in the world. MiR-342-5p was associated with Alzheimer's disease and cardio-protection. Herein, we aimed to reveal effects of miR-342-5p on cerebral ischemia injury as well as novel targets for stroke.

MATERIALS AND METHODS

AgomiR-342-5p was intracerebroventricularly injected into the middle cerebral artery occlusion (MCAO) mouse models to evaluate functions of miR-342-5p on cerebral ischemia. RT-qPCR and western blot assays were used to evaluate genes expression. Oxygen-glucose deprivation (OGD) was used as an in vitro model for ischemia. Viability and apoptosis ratio of neurons was evaluated by CCK-8, LDH release detection, and flow cytometry. The potential targets of miR-342-5p were predicted by Targetscan, and their interaction was confirmed by luciferase assay.

RESULTS

The intervention of miR-342-5p effectively attenuated ischemic injury in MCAO mice. MiR-342-5p overexpression could protect neurons against OGD-induced injury, as revealed by increased cell viability and BCL2 expression, and decreased LDH release, apoptosis ratio, and BAX expression in OGD-induced neurons. Mechanically, miR-342-5p could directly bound with CCAR2 to inhibit its expression. Overexpressing CARR2 aggravated the OGD-induced injury of neurons, which was partly restrained by overexpressing miR-342-5p reversed. Furthermore, miR-342-5p/CARR2 axis regulates Akt/NF-κB signaling pathway in vitro as well as in vivo cerebral ischemia models.

CONCLUSIONS

MiR-342-5p inhibited neuron apoptosis by regulating Akt/NF-kB signaling pathway via CCAR2 suppression. Our findings revealed the neuroprotection of miR-342-5p in cerebral ischemia.

Modified CFBP-bFGF targeting to ischemic brain promoted the functional recovery of cerebral ischemia

The cerebral ischemia was one of the most common causes of disability and death worldwide. Basic fibroblast growth factor (bFGF) was reported to have neuroprotective function as well as promoting angiogenesis in the ischemic brain, but the targeting delivery of bFGF to ischemic brain was still difficult. In present study, a specific peptide was used to modify bFGF to construct recombinant CFBP-bFGF, and CFBP-bFGF could specifically deliver to ischemic brain through binding with the upregulated protein-connective tissue growth factor (CTGF). When CFBP-bFGF was used in rats with cerebral ischemia by intravenous injection, local concentration of the bFGF in ischemic brain was significantly increased. In addition, enhanced neurons survival, increased angiogenesis, decreased neuroinflammation were observed, that improved the motor functional recovery of cerebral ischemic injury. These results demonstrated that the targeting delivery of CFBP-bFGF would be a potential therapeutic approach for cerebral ischemia.

Research progress of fibroblast growth factor in nervous system diseases

Fibroblast growth factors (FGF) are a group of structurally related polypeptides which constitute an elaborate signaling system with their receptors. Evidence accumulated in the years suggests that the FGF family plays a key role in the repair of central nervous system injury. The main protective mechanisms include activating the expression of PI3K-Akt, peroxisome proliferator-activated receptor (PPARγ) and other signals; inhibiting NF-κB-mediated inflammatory response, oxidative stress and apoptosis; regulating neuronal differentiation and neuronal excitability as well as participating in protection of neurovascular units and nerve function repair. This paper comprehensively summarizes the latest research progress in FGF signaling related to diseases of the central nervous system such as cerebral infarction, cerebral hemorrhage, traumatic brain injury, Alzheimer's disease, Parkinson's disease, epilepsy and depression, aiming to provide scientific basis and reference for the development of innovative FGF drugs for the prevention and treatment of neurological diseases.

A New Therapeutic Trend: Natural Medicine for Ameliorating Ischemic Stroke via PI3K/Akt Signaling Pathway

Ischemic stroke (IS) is an acute cerebrovascular disease caused by sudden arterial occlusion, which is characterized by a high morbidity, mortality, and disability rate. It is one of the most important causes of nervous system morbidity and mortality in the world. In recent years, the search for new medicine for the treatment of IS has become an attractive research focus. Due to the extremely limited time window of traditional medicine treatment, some side effects may occur, and accompanied by the occurrence of adverse reactions, the frequency of exploration with natural medicine is significantly increased. Phosphatidylinositol-3-kinase/Protein kinase B (PI3K/Akt) signaling pathway is a classical pathway for cell metabolism, growth, apoptosis, and other physiological activities. There is considerable research on medicine that treats various diseases through this pathway. This review focuses on how natural medicines (including herbs and insects) regulate important pathophysiological processes such as inflammation, oxidative stress, apoptosis, and autophagy through the PI3K/Akt signaling pathway, and the role it plays in improving IS. We found that many kinds of herbal medicine and insect medicine can alleviate the damage caused by IS through the PI3K/Akt signaling pathway. Moreover, the prescription after their combination can also achieve certain results. Therefore, this review provides a new candidate category for medicine development in the treatment of IS.

ALG-bFGF Hydrogel Inhibiting Autophagy Contributes to Protection of Blood-Spinal Cord Barrier Integrity via PI3K/Akt/FOXO1/KLF4 Pathway After SCI

Promoting blood–spinal cord barrier (BSCB) repair at the early stage plays a crucial role in treatment of spinal cord injury (SCI). Excessive activation of autophagy can prevent recovery of BSCB after SCI. Basic fibroblast growth factor (bFGF) has been shown to promote BSCB repair and locomotor function recovery in SCI. However, the therapeutic effect of bFGF via direct administration on SCI is limited because of its rapid degradation and dilution at injury site. Based on these considerations, controlled release of bFGF in the lesion area is becoming an attractive strategy for SCI repair. At present, we have designed a sustained-release system of bFGF (called ALG-bFGF) using sodium alginate hydrogel, which is able to load large amounts of bFGF and suitable for in situ administration of bFGF in vivo. Here, traumatic SCI mice models and oxygen glucose deprivation (OGD)–stimulated human brain microvascular endothelial cells were performed to explore the effects and the underlying mechanisms of ALG-bFGF in promoting SCI repair. After a single in situ injection of ALG-bFGF hydrogel into the injured spinal cord, sustained release of bFGF from ALG hydrogel distinctly prevented BSCB destruction and improved motor functional recovery in mice after SCI, which showed better therapeutic effect than those in mice treated with bFGF solution or ALG. Evidences have demonstrated that autophagy is involved in maintaining BSCB integrity and functional restoration in animals after SCI. In this study, SCI/OGD exposure–induced significant upregulations of autophagy activation-related proteins (Beclin1, ATG5, LC3II/I) were distinctly decreased by ALG-bFGF hydrogel near the baseline and not less than it both in vivo and in vitro, and this inhibitory effect contributed to prevent BSCB destruction. Finally, PI3K inhibitor LY294002 and KLF4 inhibitor NSC-664704 were applied to further explore the underlying mechanism by which ALG-bFGF attenuated autophagy activation to alleviate BSCB destruction after SCI. The results further indicated that ALG-bFGF hydrogel maintaining BSCB integrity by inhibiting autophagy activation was regulated by PI3K/Akt/FOXO1/KLF4 pathway. In summary, our current study revealed a novel mechanism by which ALG-bFGF hydrogel improves BSCB and motor function recovery after SCI, providing an effective therapeutic strategy for SCI repair.

Ginsenoside Rb1 protects from Staphylococcus aureus-induced oxidative damage and apoptosis through endoplasmic reticulum-stress and death receptor-mediated pathways

Acute lung injury (ALI) is acute uncontrolled inflammation of lung tissue that leads to high fatality both in human and animals. Staphylococcus aureus (S. aureus) could be an opportunistic, versatile bacterial etiology of ALI. Ginsenoside Rb1 (Rb1) is extracted from the Panax ginseng, which displays a wide range of biological and pharmacological effects. However, protective effects of Rb1 in S. aureus-induced ALI though endoplasmic reticulum (ER) stress and death receptor-mediated pathways have not yet been reported. Therefore, present study was planned with the aims to investigate the antioxidant and anti-apoptotic properties of Rb1 through regulation of ER stress as well as death receptor-mediated pathways in ALI induced by S. aureus in mice. In this study, four groups of healthy Kunming mice (n = 48) were used. The S. aureus (80 µl; 1 ×10⁷ CFU/10 µl) was administered intranasally to establish mice model of ALI. After 24 h of onset of S. aureus-induced ALI, the mice were injected thrice with Rb1 (40 mg/kg) intraperitoneally six hours apart. Histopathology, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), Immunohistochemistry and western blotting assay were employed in the current study. Our results suggested that Rb1 administration save lungs from pulmonary injury by reducing wet to dry (W/D) ratio, protein levels, total cells, neutrophilic count, reactive oxygen species (ROS), myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx)1 depletion. Meanwhile, Rb1 therapy ameliorated histopathology alteration of lung tissue and pro-inflammatory cytokines secretion. The gene expression of ER stress marker (PERK, AFT-6, IRE1 and CHOP) were upregulated markedly (P < .05) in S. aureus-instilled groups, which was reduced by Rb1 administration that is reveled from the result findings of the RT-qPCR and immunoblot assay. The results of immunohistochemistry for CHOP indicated the increased expression in S. aureus groups which in turn ameliorated by Rb1 treatment. The mRNA expression demonstrated that death receptor-associated genes (FasL, Fas, FADD and caspase-8) showed up-regulation in S. aureus group. The similar findings were observed for the protein expression of caspase-8, FADD and Fas. Rb1 treatment markedly (P < .05) reversed protein and mRNA expression levels of these death receptor-associated genes when compared to the S. aureus group. Taken together, Rb1 attenuated S. aureus-induced oxidative damage via the ER stress-mediated pathway and apoptosis through death receptor-mediated pathway. Conclusively, our findings provide an insight into preventive mechanism of Rb1 in ALI caused by S. aureus and hence proven a scientific baseline for the therapeutic application of Rb1.

Roles and Therapeutic Implications of Endoplasmic Reticulum Stress and Oxidative Stress in Cardiovascular Diseases

In different pathological states that cause endoplasmic reticulum (ER) calcium depletion, altered glycosylation, nutrient deprivation, oxidative stress, DNA damage or energy perturbation/fluctuations, the protein folding process is disrupted and the ER becomes stressed. Studies in the past decade have demonstrated that ER stress is closely associated with pathogenesis of obesity, insulin resistance and type 2 diabetes. Excess nutrients and inflammatory cytokines associated with metabolic diseases can trigger or worsen ER stress. ER stress plays a critical role in the induction of endothelial dysfunction and atherosclerosis. Signaling pathways including AMP-activated protein kinase and peroxisome proliferator-activated receptor have been identified to regulate ER stress, whilst ER stress contributes to the imbalanced production between nitric oxide (NO) and reactive oxygen species (ROS) causing oxidative stress. Several drugs or herbs have been proved to protect against cardiovascular diseases (CVD) through inhibition of ER stress and oxidative stress. The present article reviews the involvement of ER stress and oxidative stress in cardiovascular dysfunction and the potential therapeutic implications.

DL-3-n-butylphthalide ameliorates diabetes-associated cognitive decline by enhancing PI3K/Akt signaling and suppressing oxidative stress

DL-3-n-Butylphthalide (DL-NBP), a small molecular compound extracted from the seeds of Apium graveolens Linn (Chinese celery), has been shown to exert neuroprotective effects due to its anti-inflammatory, anti-oxidative and anti-apoptotic activities. DL-NBP not only protects against ischemic cerebral injury, but also ameliorates vascular cognitive impairment in dementia patients including AD and PD. In the current study, we investigated whether and how DL-NBP exerted a neuroprotective effect against diabetes-associated cognitive decline (DACD) in db/db mice, a model of type-2 diabetes. db/db mice were orally administered DL-NBP (20, 60, 120 mg· kg-1· d-1) for 8 weeks. Then the mice were subjected to behavioral test, their brain tissue was collected for morphological and biochemical analyses. We showed that oral administration of DL-NBP significantly ameliorated the cognitive decline with improved learning and memory function in Morris water maze testing. Furthermore, DL-NBP administration attenuated diabetes-induced morphological alterations and increased neuronal survival and restored the levels of synaptic protein PSD95, synaptophysin and synapsin-1 as well as dendritic density in the hippocampus, especially at a dose of 60 mg/kg. Moreover, we revealed that DL-NBP administration suppressed oxidative stress by upregulating Nrf2/HO-1 signaling, and increased brain-derived neurotrophic factor (BDNF) expression by activating PI3K/Akt/CREB signaling in the hippocampus. These beneficial effects of DL-NBP were observed in high glucose-treated PC12 cells. Our results suggest that DL-NBP may be a potential pharmacologic agent for the treatment of DACD.

Regulation of the CoA Biosynthetic Complex Assembly in Mammalian Cells

Coenzyme A (CoA) is an essential cofactor present in all living cells. Under physiological conditions, CoA mainly functions to generate metabolically active CoA thioesters, which are indispensable for cellular metabolism, the regulation of gene expression, and the biosynthesis of neurotransmitters. When cells are exposed to oxidative or metabolic stress, CoA acts as an important cellular antioxidant that protects protein thiols from overoxidation, and this function is mediated by protein CoAlation. CoA and its derivatives are strictly maintained at levels controlled by nutrients, hormones, metabolites, and cellular stresses. Dysregulation of their biosynthesis and homeostasis has deleterious consequences and has been noted in a range of pathological conditions, including cancer, diabetes, Reye’s syndrome, cardiac hypertrophy, and neurodegeneration. The biochemistry of CoA biosynthesis, which involves five enzymatic steps, has been extensively studied. However, the existence of a CoA biosynthetic complex and the mode of its regulation in mammalian cells are unknown. In this study, we report the assembly of all five enzymes that drive CoA biosynthesis, in HEK293/Pank1β and A549 cells, using the in situ proximity ligation assay. Furthermore, we show that the association of CoA biosynthetic enzymes is strongly upregulated in response to serum starvation and oxidative stress, whereas insulin and growth factor signaling downregulate their assembly.

The Role of Tenascin-C in Tissue Injury and Repair After Stroke

Stroke is still one of the most common causes for mortality and morbidity worldwide. Following acute stroke onset, biochemical and cellular changes induce further brain injury such as neuroinflammation, cell death, and blood-brain barrier disruption. Matricellular proteins are non-structural proteins induced by many stimuli and tissue damage including stroke induction, while its levels are generally low in a normal physiological condition in adult tissues. Currently, a matricellular protein tenascin-C (TNC) is considered to be an important inducer to promote neuroinflammatory cascades and the resultant pathology in stroke. TNC is upregulated in cerebral arteries and brain tissues including astrocytes, neurons, and brain capillary endothelial cells following subarachnoid hemorrhage (SAH). TNC may be involved in blood-brain barrier disruption, neuronal apoptosis, and cerebral vasospasm via the activation of mitogen-activated protein kinases and nuclear factor-kappa B following SAH. In addition, post-SAH TNC levels in cerebrospinal fluid predicted the development of delayed cerebral ischemia and angiographic vasospasm in clinical settings. On the other hand, TNC is reported to promote fibrosis and exert repair effects for an experimental aneurysm via macrophages-induced migration and proliferation of smooth muscle cells. The authors review TNC-induced inflammatory signal cascades and the relationships with other matricellular proteins in stroke-related pathology.

Modulatory Effect of Myokines on Reactive Oxygen Species in Ischemia/Reperfusion

There is a growing body of evidence showing the importance of physical activity against acute ischemic events in various organs. Ischemia/reperfusion injury (I/R) is characterized by tissue damage as a result of restriction and subsequent restoration of blood supply to an organ. Oxidative stress due to increased reactive oxygen species formation and/or insufficient antioxidant defense is considered to play an important role in I/R. Physical activity not only decreases the general risk factors for ischemia but also confers direct anti-ischemic protection via myokine production. Myokines are skeletal muscle-derived cytokines, representing multifunctional communication channels between the contracting skeletal muscle and other organs through an endocrine manner. In this review, we discuss the most prominent members of the myokines (i.e., brain-derived neurotrophic factor (BDNF), cathepsin B, decorin, fibroblast growth factors-2 and -21, follistatin, follistatin-like, insulin-like growth factor-1; interleukin-6, interleukin-7, interleukin-15, irisin, leukemia inhibitory factor, meteorin-like, myonectin, musclin, myostatin, and osteoglycin) with a particular interest in their potential influence on reactive oxygen and nitrogen species formation or antioxidant capacity. A better understanding of the mechanism of action of myokines and particularly their participation in the regulation of oxidative stress may widen their possible therapeutic use and, thereby, may support the fight against I/R.

Growth factors-based therapeutic strategies and their underlying signaling mechanisms for peripheral nerve regeneration

Peripheral nerve injury (PNI), one of the most common concerns following trauma, can result in a significant loss of sensory or motor function. Restoration of the injured nerves requires a complex cellular and molecular response to rebuild the functional axons so that they can accurately connect with their original targets. However, there is no optimized therapy for complete recovery after PNI. Supplementation with exogenous growth factors (GFs) is an emerging and versatile therapeutic strategy for promoting nerve regeneration and functional recovery. GFs activate the downstream targets of various signaling cascades through binding with their corresponding receptors to exert their multiple effects on neurorestoration and tissue regeneration. However, the simple administration of GFs is insufficient for reconstructing PNI due to their short half‑life and rapid deactivation in body fluids. To overcome these shortcomings, several nerve conduits derived from biological tissue or synthetic materials have been developed. Their good biocompatibility and biofunctionality made them a suitable vehicle for the delivery of multiple GFs to support peripheral nerve regeneration. After repairing nerve defects, the controlled release of GFs from the conduit structures is able to continuously improve axonal regeneration and functional outcome. Thus, therapies with growth factor (GF) delivery systems have received increasing attention in recent years. Here, we mainly review the therapeutic capacity of GFs and their incorporation into nerve guides for repairing PNI. In addition, the possible receptors and signaling mechanisms of the GF family exerting their biological effects are also emphasized.

Molecular Mechanisms Involved in Neural Substructure Development during Phosphodiesterase Inhibitor Treatment of Mesenchymal Stem Cells

Stem cells are highly important in biology due to their unique innate ability to self-renew and differentiate into other specialised cells. In a neurological context, treating major injuries such as traumatic brain injury, spinal cord injury and stroke is a strong basis for research in this area. Mesenchymal stem cells (MSC) are a strong candidate because of their accessibility, compatibility if autologous, high yield and multipotency with a potential to generate neural cells. With the use of small-molecule chemicals, the neural induction of stem cells may occur within minutes or hours. Isobutylmethyl xanthine (IBMX) has been widely used in cocktails to induce neural differentiation. However, the key molecular mechanisms it instigates in the process are largely unknown. In this study we showed that IBMX-treated mesenchymal stem cells induced differentiation within 24 h with the unique expression of several key proteins such as Adapter protein crk, hypoxanthine-guanine phosphoribosyltransferase, DNA topoisomerase 2-beta and Cell division protein kinase 5 (CDK5), vital in linking signalling pathways. Furthermore, the increased expression of basic fibroblast growth factor in treated cells promotes phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase (MAPK) cascades and GTPase–Hras interactions. Bioinformatic and pathway analyses revealed upregulation in expression and an increase in the number of proteins with biological ontologies related to neural development and substructure formation. These findings enhance the understanding of the utility of IBMX in MSC neural differentiation and its involvement in neurite substructure development.

B7-33, a Functionally Selective Relaxin Receptor 1 Agonist, Attenuates Myocardial Infarction-Related Adverse Cardiac Remodeling in Mice

Background

Human relaxin‐2 is a peptide hormone capable of pleiotropic effects in several organ systems. Its recombinant formulation (serelaxin) has been demonstrated to reduce infarct size and prevent excessive scar formation in animal models of cardiac ischemia‐reperfusion injury. B7‐33, a synthetically designed peptide analogous to B‐chain of relaxin‐2, invokes signaling at relaxin family peptide receptor 1 (cognate receptor for relaxin‐2) by preferentially phosphorylating the mitogen‐activated protein kinase extracellular signal‐regulated kinase 1/2. We sought to investigate the effects of B7‐33 treatment post ischemia‐reperfusion injury in mice.

Methods and Results

Adult male CD1 mice were subjected to ischemia‐reperfusion via ligation of left anterior descending artery for 30 minutes, followed by 24 hours or 7 days of reperfusion. Echocardiography was performed to assess cardiac function, and cardiac tissue was stained to determine infarct size at 24 hours. B7‐33 significantly reduced infarct size (21.99% versus 45.32%; P=0.02) and preserved fractional shortening (29% versus 23%; P=0.02) compared with vehicle. The difference in fractional shortening further increased at 7 days post myocardial infarction (29% versus 20% for B7‐33 and vehicle groups, respectively). In vitro, primary cardiomyocytes were isolated from adult hearts and subjected to simulated ischemia‐reperfusion injury (simulated ischemia reoxygenation). B7‐33 (50 and 100 nmol/L) improved cell survival and reduced the expression of GRP78 (glucose regulated protein), an endoplasmic reticulum stress marker. Subsequently, B7‐33 (100 nmol/L) reduced tunicamycin (2.5 μg/mL) induced upregulation of GRP78 in an extracellular signal‐regulated kinase 1/2–dependent manner.

Conclusions

B7‐33 confers acute cardioprotection and limits myocardial infarction–related adverse remodeling in mice by attenuating cardiomyocyte death and endoplasmic reticulum stress as well as preserving cardiac function.

Fibroblast Growth Factor 2 Attenuates Renal Ischemia-Reperfusion Injury via Inhibition of Endoplasmic Reticulum Stress

Acute kidney injury (AKI) is a serious clinical disease that is mainly caused by renal ischemia-reperfusion (I/R) injury, sepsis, and nephrotoxic drugs. The pathologic mechanism of AKI is very complex and may involve oxidative stress, inflammatory response, autophagy, apoptosis, and endoplasmic reticulum (ER) stress. The basic fibroblast growth factor (FGF2) is a canonic member of the FGF family that plays a crucial role in various cellular processes, including organ development, wound healing, and tissue regeneration. However, few studies have reported the potential therapeutic effect of FGF2 in the repair of renal ischemic injury in the past two decades. In the present study, we investigated the protective effect of FGF2 on renal I/R injury using Sprague-Dawley and NRK-52E cells. Our results showed that FGF2 significantly attenuates the apoptosis of kidney tissues after I/R injury through the inhibition of excessive ER stress. Moreover, FGF2 also alleviated the excessive ER stress and apoptosis in cultured NRK-52E cells injured by tert-Butyl hydroperoxide (TBHP). Significantly, phosphatidylinositol 3-kinase (PI3K)-selective inhibitor LY294002 and mitogen-activated protein kinase kinase (MEK)-selective inhibitor U0126 were utilized in the present study to examine the protective mechanism of FGF2. Our in vitro experimental results confirmed that both LY294002 and U0126 largely abolished the protective effect of FGF2. Taken together, the findings of the present study indicated that FGF2 attenuates I/R-induced renal epithelial apoptosis by suppressing excessive ER stress via the activation of the PI3K/AKT and MEK-ERK1/2 signaling pathways.

Fibroblast Growth Factor 10 Attenuates Renal Damage by Regulating Endoplasmic Reticulum Stress After Ischemia-Reperfusion Injury

Renal ischemia–reperfusion (I/R) injury is a predominant cause of acute kidney injury (AKI), the pathologic mechanism of which is highly complex involving reactive oxygen species (ROS) accumulation, inflammatory response, autophagy, apoptosis as well as endoplasmic reticulum (ER) stress. Fibroblast growth factor 10 (FGF10), as a multifunctional growth factor, plays crucial roles in embryonic development, adult homeostasis, and regenerative medicine. Herein, we investigated the molecular pathways underlying the protective effect of FGF10 on renal I/R injury using Sprague–Dawley rats. Results showed that administration of FGF10 not only effectively inhibited I/R-induced activation of Caspase-3 and expression of Bax, but also alleviated I/R evoked expression of ER stress-related proteins in the kidney including CHOP, GRP78, XBP-1, and ATF-4 and ATF-6. The protective effect of FGF10 against apoptosis and ER stress was recapitulated by in vitro experiments using oxidative damaged NRK-52E cells induced by tert-Butyl hydroperoxide (TBHP). Significantly, U0126, a selective noncompetitive inhibitor of MAP kinase kinases (MKK), largely abolished the protective role of FGF10. Taken together, both in vivo and in vitro experiments indicated that FGF10 attenuates I/R-induced renal epithelial apoptosis by suppressing excessive ER stress, which is, at least partially, mediated by the activation of the MEK–ERK1/2 signaling pathway. Therefore, our present study revealed the therapeutic potential of FGF10 on renal I/R injury.

Puerarin attenuates hypoxia-resulted damages in neural stem cells by up-regulating microRNA-214

Puerarin has been reported to be useful in protection against hypoxia-induced injury. In our current study, we attempted to explore the protective effects of puerarin against hypoxia-caused damages in neural stem cells (NSCs). Additionally, the relative molecular underpinning studies preliminarily proceeded. NSCs were pre-incubated with puerarin before the hypoxic stimulus. MicroRNA-214 (miR-214) inhibitor was transfected into NSCs. Subsequently, the viability of NSCs was assessed by CCK-8 assay. Flow cytometry was employed to detect apoptotic cells after staining. qRT-PCR was performed to quantify miR-214. Western blot was applied for analyzing the expression of apoptosis-relative proteins and regulators. We found that puerarin alleviated hypoxia-induced apoptosis and maintained cell viability. Hypoxia-evoked up-regulation of miR-214 was further enhanced by puerarin. By contrast, miR-214-deficient NSCs showed the reduction in cell viability and the facilitation in apoptosis progress after pre-treatment with puerarin and stimulation in a hypoxia circumstance. Additionally, puerarin restored the phosphorylation of relative regulators, which was originally blunted by hypoxia. However, puerarin did not evidently restore the phosphorylation for response to hypoxia in miR-214-silenced NSCs. In conclusion, puerarin might be applied as a novel agent to ameliorate hypoxia-evoked damages in NSCs. Molecularly, miR-214 might be implicated in the protective roles of puerarin.

Fabrication of porous bovine pericardium scaffolds incorporated with bFGF for tissue engineering applications

BACKGROUND

The design and fabrication of porous scaffolds are important issues for tissue engineering applications. In this study, we attempted to fabricate porous scaffolds using bovine pericardium (BP) and examined whether these scaffolds were beneficial for cell ingrowth and bioactive factors delivery.

METHODS

A vacuum-freeze-thawing-Triton X-100 (VFTT) protocol was used to fabricate porous BP scaffolds. The porous and mechanical properties were assessed using histology, scanning electron microscopy, and mechanical assay. The fabricated scaffolds were seeded with mesenchymal stem cells (MSCs), and cell ingrowth was evaluated. Basic fibroblast growth factor (bFGF) was subsequently incorporated into the fabricated scaffolds. The bioactive factor delivery capacity was evaluated using loading and release studies. The bioactivity of released bFGF was assessed using a rat subcutaneous model.

RESULTS

The BP scaffolds fabricated by the VFTT protocol displayed interconnected porous structures with porosity of 6.82 ± 1.36%.There were no significant differences in thickness, ultimate load, Young's modulus, and ultimate tensile strength between the fabricated porous BP scaffolds and native BPs (all P > .05). However, the water content of BPs was slightly reduced after VFTT treatment (P < .05). Cell ingrowth analysis showed that the seeded MSCs penetrated into the porous BP scaffolds with time of culture, while MSCs were limited to the surface layers of native BPs. Furthermore, bFGF was observed to be effectively loaded onto and released from the porous BP scaffolds. The released bFGF increased the phosphorylation levels of Akt, ERK 1/2, and MEK1/2, promoted host MSC recruitment, and inhibited myofibroblast differentiation in vivo.

CONCLUSIONS

The porous BP scaffolds fabricated using a VFTT protocol were promising natural scaffolds for tissue engineering applications, since they had considerable mechanical properties as native BPs, supplied porous channels for cell ingrowth, and possessed bioactive factors delivery capability.

FGF10 Enhances Peripheral Nerve Regeneration via the Preactivation of the PI3K/Akt Signaling-Mediated Antioxidant Response

The process of axonal regeneration after peripheral nerve injury (PNI) is slow and mostly incomplete. Previous studies have investigated the neuroprotective effects of fibroblast growth factor 10 (FGF10) against spinal cord injury and cerebral ischemia brain injury. However, the role of FGF10 in peripheral nerve regeneration remains unknown. In this study, we aimed to investigate the underlying therapeutic effects of FGF10 on nerve regeneration and functional recovery after PNI and to explore the associated mechanism. Our results showed that FGF10 administration promoted axonal regeneration and functional recovery after nerve damage. Moreover, exogenous FGF10 treatment also prevented SCs from excessive oxidative stress-induced apoptosis, which was probably related to the activation of phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) signaling. The inhibition of the PI3K/Akt pathway by the specific inhibitor LY294002 partially reversed the therapeutic effects of FGF10 both in vivo and in vitro. Thus, from our perspective, FGF10 may be a promising therapeutic drug for repairing sciatic nerve damage through countering excessive oxidative stress-induced SC apoptosis.

FGF-2 Attenuates Neuronal Apoptosis via FGFR3/PI3k/Akt Signaling Pathway After Subarachnoid Hemorrhage

Neuronal apoptosis is a common and critical pathology following subarachnoid hemorrhage (SAH). We investigated the anti-apoptotic property of fibroblast growth factor (FGF)-2 after SAH in rats. A total of 289 rats underwent endovascular perforation to induce SAH or sham operation. Three dosages (3, 9, or 27 μg) of recombinant FGF-2 (rFGF-2) or vehicle was administered intranasally to rats 30 min after SAH induction. The pan-FGF receptor (FGFR) inhibitor PD173074 or vehicle was administered intracerebroventricularly (i.c.v.) 1 h before modeling, in addition to rFGF-2 treatment. Small interfering ribonucleic acid (siRNA) for FGFR1 and FGFR3 or scrambled siRNA was administered i.c.v. 48 h before SAH induction in addition to rFGF-2 treatment. Anti-FGF-2 neutralizing antibody or normal mouse immunoglobulin G (IgG) was administered i.c.v. 1 h before SAH model. Neurobehavioral tests, SAH severity, brain water content, immunofluorescence, Fluoro-Jade C, TUNEL staining, and western blot were evaluated. The expression of FGF-2, FGFR1, and FGFR3 increased after SAH. FGFR1 and FGFR3 were expressed in the neurons. Nine micrograms of FGF-2 alleviated neurological impairments, brain edema, and neuronal apoptosis following SAH. A rFGF-2 treatment improved motor skill learning and spatial memory and increased the number of surviving neurons postinjury to 28 days after SAH. PD173074 abolished the anti-apoptotic effects of rFGF-2 via suppression of the expression of PI3k, phosphorylated Akt (p-Akt), and Bcl-2 leading to enhancement of the expression of Bax. FGFR3 siRNA worsened neurobehavioral function and suppressed the expression of PI3k, p-Akt, and Bcl-2 rather than FGFR1 siRNA in SAH rats treated with rFGF-2. Anti-FGF-2 neutralizing antibody suppressed the expression of PI3k and p-Akt after SAH. FGF-2 may be a promising therapy to reduce post-SAH neuronal apoptosis via activation of the FGFR3/PI3k/Akt signaling pathway.

Manilkara zapota (L.) P. Royen Leaf Water Extract Induces Apoptosis in Human Hepatocellular Carcinoma (HepG2) Cells via ERK1/2/Akt1/JNK1 Signaling Pathways

Manilkara zapota (L.) P. Royen, called sapodilla, or locally known as ciku, belongs to the family Sapotaceae. We found that Manilkara zapota leaf water extract has cytotoxic effect against human hepatocellular carcinoma (HepG2) cell line in our earlier study. Therefore, this study aimed to explore the anticancer properties of Manilkara zapota leaf water extract in HepG2 cells. We also aimed to unravel yet undiscovered mechanisms and identified several expressed genes whose functions in cytotoxicity activity of Manilkara zapota leaf water extract in HepG2 cells have not been well-studied. The apoptosis and intracellular reactive oxygen species (ROS) activities were analyzed using Annexin V-propidium iodide staining and dichlorodihydrofluorescein diacetate, respectively, by NovoCyte Flow Cytometer. Bax and Bcl-2 expression were assessed using Enzyme-Linked Immunosorbent Assay. The associated molecular pathways were evaluated by quantitative real-time PCR. Overall analyses revealed that Manilkara zapota leaf water extract can increase percentage of early apoptotic cells, induce the formation of ROS, upregulate c-Jun N-terminal kinase 1 (JNK1) and inducible nitric oxide synthase (iNOS), and reduce Akt1 and vascular endothelial growth factor A (VEGFA) transcriptional activities. Our data suggest that Manilkara zapota leaf water extract can suppress the growth of HepG2 cells via modulation of ERK1/2/Akt1/JNK1 transcriptional expression.

Vascular smooth muscle cells activate PI3K/Akt pathway to attenuate myocardial ischemia/reperfusion-induced apoptosis and autophagy by secreting bFGF

BACKGROUND

Vascular smooth muscle cells (VSMCs) has been reported to be implicated in atherosclerotic plaque instability and rupture. Recently, it has been demonstrated that VSMCs block the progression of cardiac remodeling and thus promoting cardiac function in a rat myocardial infarction model. However, the detailed molecular mechanism of how VSMCs contributes to recovery in myocardial ischemia/reperfusion remains not fully understood.

METHODS

We have isolated, identified and cultured VSMCs from rats to co-culture with rat cardiomyocyte H9C2. To culture H9C2 cells under hypoxia, we utilized CoCl₂-containing medium to culture for 8 h and then was replaced with normal media for additional 16 h. Cell viability was examined by MTT assay and apoptosis was determined by flow cytometry. Infarcted area of myocardial tissue was measured by TTC staining.

RESULTS

VSMCs was shown to promote cell viability and inhibit apoptosis of H9C2 cells under hypoxia, which exhibited upregulated anti-apoptotic protein Bcl-2 and autophagy-related protein p62, whereas pro-apoptotic protein cleaved caspase-3 and the level of LC3II/LC3I were downregulated. Then, we confirmed VSMCs played the contributory role in cell viability of H9C2 under hypoxia by secreting bFGF, which exerted its function through PI3K/Akt pathway. Finally, in vivo, the results demonstrated that VSMCs transplantation contributed to recovery of myocardial ischemia.

CONCLUSION

We determine that VSMCs promote recovery of infarcted cardiomyocyte through secretion of bFGF, which then activating PI3K/Akt pathway to inhibit apoptosis and autophagy. These findings provide more insights into the molecular mechanism underlying VSMCs contributing to recovery of myocardial I/R and facilitate developing therapeutical strategies for treating heart diseases.

PI3K/Akt and HIF‑1 signaling pathway in hypoxia‑ischemia (Review)

Hypoxia-ischemia (H-I) is frequently observed in perinatal asphyxia and other diseases. It can lead to serious cardiac injury, cerebral damage, neurological disability and mortality. Previous studies have demonstrated that the phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) signaling pathway, which regulates a wide range of cellular functions, is involved in the resistance response to H-I through the activation of proteins associated with survival and inactivation of apoptosis-associated proteins. It can also regulate the expression of hypoxia-induced factor-1α (HIF-1α). HIF-1α can further regulate the expression of downstream proteins involved in glucose metabolism and angiogenesis, such as vascular endothelial growth factor and erythropoietin, to facilitate ischemic adaptation. Notably, HIF-1α may also induce detrimental effects. The effects of HIF-1 on ischemic outcomes may be dependent on the H-I duration, animal age and species. Thus, further investigation of the PI3K/Akt signaling pathway may provide further insights of the potential targets for treating diseases accompanied by H-I.

SC79, the AKT Activator Protects Cerebral Ischemia in a Rat Model of Ischemia/Reperfusion Injury

Background

Activation of AKT pathway attenuates brain damage and neuronal apoptosis during cerebral ischemia/reperfusion (I/R) injury. SC79 is a novel, selective and highly-efficient Akt activator. This study aimed to investigate the neuroprotective effect of SC79 against cerebral I/R injury in a rat model, and to explore the possible underlying mechanisms.

Material/Methods

Male Sprague-Dawley rats received cerebral ischemia for 1 hour, followed by brain reperfusion for 0.5–24 hours. The cerebral I/R injury animal model were treated with SC79 alone or SC79 in combination with LY294002. Western blots were used to detect the levels of expression of phosphatidylinositol AKT (p-Akt), Bax, and bcl-2. Twenty-four hours after cerebral I/R, the degree of brain injury was evaluated by detecting the neurological deficit score (NDS). The infarct rate of brain tissue was observed by TTC (2, 3, 5-triphenyltetrazolium chloride) staining. TUNEL (terminal deoxynucleotidyl transferase-mediated UTP nick end labeling) staining was used to detect cell apoptosis.

Results

p-Akt was activated during early cerebral I/R at 0.5 hours, and reached the highest levels at 4 hours, then gradually decreased from 6 hours, and reached and maintained the lowest levels at 12–24 hours. Bax expression was gradually increased from 6 hours and reached the highest level at 24 hours. However, bcl-2 expression was gradually increased and reached the highest levels at 4 hours, then gradually decreased from 6 hours, and reached the lowest levels at 24 hours. Administration of SC79 decreased infarct volumes and improved neurological function significantly. LY294002 in combination with SC79 lost the capability of SC79 to resist the cerebral I/R injury. SC79 treatment alone activated p-Akt and promoted anti-apoptotic bcl-2 and inhibited anti-apoptotic Bax expression in middle cerebral artery occlusion (MCAO) mice. However, combined SC79 and LY294002 treatment abolished SC79-induced p-Akt activity, inhibited anti-apoptotic bcl-2 and promoted anti-apoptotic Bax expression in MCAO mice. Furthermore, SC79 treatment alone attenuated apoptotic neuronal cell death, but abolished this effect in SC79 in combination with LY294002 treated groups.

Conclusions

SC79 significantly increased Akt activation and reduced infarct volume and subsequently improved neurological function in ischemic brain after cerebral I/R injury in rats. These findings suggested that SC79 may be as a neuroprotective drug to be potentially used in the clinic.

The protective effects of ethanolic extract of Clematis terniflora against corticosterone-induced neuronal damage via the AKT and ERK1/2 pathway

Chronic stress induces neuronal cell death, which can cause nervous system disorders including Parkinson’s disease and Alzheimer’s disease. In this study, we evaluated the neuroprotective effects of Clematis terniflora extract (CTE) against corticosterone-induced apoptosis in rat pheochromocytoma (PC12) cells, and also investigated the underlying molecular mechanisms. At concentrations of 300 and 500 μg/ml, CTE significantly decreased apoptotic cell death and mitochondrial damage induced by 200 μM corticosterone. CTE decreased the expression levels of endoplasmic reticulum (ER) stress proteins GRP78, GADD153, and mitochondrial damage-related protein BAD, suggesting that it downregulates ER stress evoked by corticosterone. Furthermore, our results suggested that these protective effects were mediated by the upregulation of p-AKT and p-ERK1/2, which are involved in cell survival signaling. Collectively, our results indicate that CTE can lessen neural damage caused by chronic stress.

Electroacupuncture Inhibits Apoptosis of Peri-Ischemic Regions via Modulating p38, Extracellular Signal-Regulated Kinase (ERK1/2), and c-Jun N Terminal Kinases (JNK) in Cerebral Ischemia-Reperfusion-Injured Rats

BACKGROUND Previous studies suggested that inhibition of apoptosis prevents the dysfunction of ischemia-reperfusion injury. In the pathogenesis of ischemia-reperfusion injury, JNK/ERK1/2 and p38 play an essential role in regulation of cell apoptosis. Electroacupuncture (EA), a form of acupuncture, has demonstrated superiority in preventing ischemia-reperfusion injury, but the underlying mechanism is unclear. In the present study, we explored the effects of electroacupuncture at Shenting (GV24) and Baihui (GV20) acupoints on focal cerebral ischemia-reperfusion (MCAO) rats, and explored whether JNK/ERK1/2- and p38-mediated cell apoptosis are involved. MATERIAL AND METHODS The rats were divided into a sham operation control group, an ischemia group, and an electroacupuncture group with acupuncture applied for 10 days (30 min per day). TTC staining was used to calculate the ischemic brain volume. TUNEL staining and transmission electron microscopy were used to detect cell apoptosis. Western blot analysis and Bio-Plex were used to detect JNK, p38, ERK1/2, Bcl-2, and Bax protein expression. RESULTS We found that electroacupuncture at day 10 significantly reduced cerebral infarction. In addition, electroacupuncture suppressed activation of JNK and p38, while enhancing the activation of ERK1/2 in the peri-ischemic regions. Consequently, the effect of electroacupuncture on these pathways resulted in the inhibition of apoptosis, which was demonstrated by TUNEL and transmission electron microscopy. We found that electroacupuncture upregulated the anti-apoptotic Bcl-2/Bax ratio in peri-ischemic regions. CONCLUSIONS Our findings suggest that inhibition of cell apoptosis via regulating multiple signaling pathways might be a mechanism whereby electroacupuncture has a positive therapeutic effect on post-stroke impairment.

Actinidia chinensis planch polysaccharide protects against hypoxia‑induced apoptosis of cardiomyocytes in vitro

Cardiac hypertrophy is frequently accompanied by ischemic heart disease. Actinidia chinensis planch polysaccharide (ACP) is the main active compound from Actinidia chinensis planch. In the present study, a cardiac hypertrophy model was produced by treating cells with Angiotensin II (Ang II), which was used to investigate whether ACP protected against cardiac hypertrophy in vitro. It was demonstrated that ACP alleviated Ang II‑induced cardiac hypertrophy. In addition, pretreatment with ACP prior to hypoxic culture reduced the disruption of the mitochondrial membrane potential as investigated by flow cytometry. Cell Counting kit‑8 analysis demonstrated that ACP maintained the cell viability of cardiomyocytes. The flow cytometric analysis revealed that ACP inhibited hypoxia‑induced apoptosis in cardiomyocytes treated with Ang II. Additionally, reverse transcription‑polymerase chain reaction and western blotting assays demonstrated that ACP decreased the expression of apoptosis‑associated genes including apoptosis‑inducing factor mitochondria associated 1, the cysteinyl aspartate specific proteinases caspases‑3/8/9, and cleaved caspases‑3/8/9. The results of the present study also demonstrated that ACP inhibited the activation of the extracellular signal‑regulated kinase 1/2 (ERK1/2) and phosphoinositide 3‑kinase/protein kinase B (PI3K/AKT) signaling pathways. Furthermore, the specific activation of ERK1/2 and PI3K/AKT reversed the apoptotic‑inhibitory effect of ACP. In conclusion, the protective effects of ACP against hypoxia‑induced apoptosis may depend on depressing the ERK1/2 and PI3K/AKT signaling pathways in cardiomyocytes treated with Ang II.

Neuroprotective effects of protein tyrosine phosphatase 1B inhibitor on cerebral ischemia/reperfusion in mice

Akt (Protein kinase B, PKB), a serine/threonine kinase, plays a critical role in cell development, growth, and survival. Akt phosphorylation mediates a neuroprotective effect against ischemic injury. Recently, a protein-tyrosine phosphatase-1B (PTP1B) inhibitor (KY-226) was developed to elicit anti-diabetic and anti-obesity effects via enhancement of insulin signaling. Previously, we reported that the nonselective PTP1B inhibitor, sodium orthovanadate, rescued neurons from delayed neuronal death during brain ischemia. In this study, we confirmed the ameliorative effects of KY-226 on ischemia/reperfusion (I/R) injury using a murine model of middle cerebral artery occlusion (MCAO). ICR mice were subjected to MCAO for 2 h followed by reperfusion. Although KY-226 permeability was poor through the blood-brain barrier (BBB) of normal mice, it could penetrate through the BBB of mice after I/R insult. Intraperitoneal KY-226 administration elicited dose-dependent reductions in infarcted brain areas and improved neurological deficits. The neuroprotective effects of KY-266 were obtained when administered within 0.5 h after reperfusion. KY-226 (10 mg/kg) also restored reduced Akt phosphorylation and eNOS phosphorylation (Ser-1177) levels following I/R insult. Moreover, 10 mg/kg of KY-226 improved I/R-induced decreased extracellular signal-regulated kinase (ERK) phosphorylation. Furthermore, KY-226 attenuated the generation of reactive oxygen species (ROS) in mouse cortex. These results suggest that KY-226 may act as a novel therapeutic candidate for ischemic stroke. Activation of Akt and ERK possibly underlie the neuroprotective mechanism of KY-226.

Heparin-based coacervate of bFGF facilitates peripheral nerve regeneration by inhibiting endoplasmic reticulum stress following sciatic nerve injury

Creating a microenvironment at the injury site that favors axonal regrowth and remyelinationis pivotal to the success of therapeutic reinnervation. The mature myelin sheath of the peripheral nervous system depends on active participation of Schwann cells to form new cytoskeletal components and tremendous amounts of relevant neurotrophic factors. In this study, we utilized a new biomaterial for growth factor delivery consisting of a biocompatible polycation, poly(ethylene argininylaspartatediglyceride) and heparin. It is capable of binding a variety of growth factors to deliver basic fibroblast growth factor (bFGF) through polyvalent ionic interactions for nerve repair. In vitro assays demonstrated that the bFGF loading efficiency reached 10 μg and this delivery vehicle could control the release of bFGF. In vivo, the coacervate enhanced bFGF bioavailability, which improved both motor and sensory function. It could also acceleratemyelinated fiber regeneration and remyelination and promote Schwann cells proliferation. Furthermore, the neuroprotective effect of bFGF-coacervate in sciatic nerve injury was associated with the alleviation of endoplasmic reticulum stress signal. This heparin-based delivery platform leads to increased bFGF loading efficiency and better controls its release, which will provide an effective strategy for peripheral nerve injury regeneration therapy.

Melatonin protects brain against ischemia/reperfusion injury by attenuating endoplasmic reticulum stress

Endoplasmic reticulum (ER) stress plays a vital role in mediating ischemic reperfusion damage in brain. In this study, we evaluated whether melatonin inhibits ER stress in cultured neurons exposed to oxygen and glucose deprivation (OGD) and in rats subjected to transient focal cerebral ischemia. Sprague-Dawley rats were treated with melatonin (5 mg/kg) or control at reperfusion onset after transient occlusion of the right middle cerebral artery (MCA) for 90 min. Brain infarction and hemorrhage within infarcts were measured. The expression of ER stress proteins of phosphorylation of PRKR-like endoplasmic reticulum kinase (p-PERK), phosphorylation of eukaryotic translation initiation factor 2α (p-eIF2α), activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were detected by western blotting and immunohistochemistry analysis. The terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) method, cleaved caspase-3 and cytochrome c were used to investigate cell apoptosis in OGD-induced cultured neurons. Our results demonstrated that animals treated with melatonin had significantly reduced infarction volumes and individual cortical lesion sizes as well as increased numbers of surviving neurons. Melatonin can significantly modulate protein levels by decreasing both p-PERK and p-eIF2α in the ischemic core and penumbra. Moreover, the expressions of ATF4 and CHOP were restrained in the ischemic core and penumbra, respectively. Furthermore, pretreatment with melatonin at 10–100 µM effectively reduced the levels of p-PERK and p-eIF2α in cultured neurons after OGD injury. Melatonin treatment also effectively decreased neuron apoptosis resulting from OGD-induced neuron injury. These results indicate that melatonin effectively attenuated post-ischemic ER stress after ischemic stroke.

PLCγ2 promotes apoptosis while inhibits proliferation in rat hepatocytes through PKCD/JNK MAPK and PKCD/p38 MAPK signalling

OBJECTIVES

The PLCG2 (PLCγ2) gene is a member of PLC gene family encoding transmembrane signalling enzymes involved in various biological processes including cell proliferation and apoptosis. Our earlier study indicated that PLCγ2 may be involved in the termination of regeneration of the liver which is mainly composed of hepatocytes, but its exact biological function and molecular mechanism in liver regeneration termination remains unclear. This study aims to examine the role of PLCγ2 in the growth of hepatocytes.

MATERIALS AND METHODS

A recombinant adenovirus expressing PLCγ2 was used to infect primary rat hepatocytes. PLCγ2 mRNA and protein levels were detected by qRT-PCR and Western blot. The subcellular location of PLCγ2 protein was tested by an immunofluorescence assay. The proliferation of hepatocytes was measured by MTT assay. The cell cycle and apoptosis were analysed by flow cytometry. Caspase-3, -8 and -9 activities were measured by a spectrophotometry method. Phosphorylation levels of PKCD, JNK and p38 in the infected cells were detected by Western blot. The possible mechanism underlying the role of PLCγ2 in hepatocyte growth was also explored by adding a signalling pathway inhibitor.

RESULTS

Hepatocyte proliferation was dramatically reduced, while cell apoptosis was remarkably increased. The results demonstrated that PLCγ2 increased the phosphorylation of PKCD, p38 and JNK in rat hepatocytes. After PKCD activity was inhibited by the inhibitor Go 6983, the levels of both p-p38 and p-JNK MAPKs significantly decreased, and PLCγ2-induced cell proliferation inhibition and cell apoptosis were obviously reversed.

CONCLUSIONS

This study showed that PLCγ2 regulates hepatocyte growth through PKCD-dependently activating p38 MAPK and JNK MAPK pathways; this result was experimentally based on the further exploration of the effect of PLCγ2 on hepatocyte growth in vivo.

bFGF plays a neuroprotective role by suppressing excessive autophagy and apoptosis after transient global cerebral ischemia in rats

Transient global cerebral ischemia (tGCI) is a cerebrovascular disorder that can cause apoptotic neuronal damage and functional deficits. Basic fibroblast growth factor (bFGF) was reported to be highly expressed in the central nervous system (CNS) and to exert neuroprotective effects against different CNS diseases. However, the effects of bFGF on tGCI have not been studied intensively. This study was conducted to investigate the effect of bFGF and its underlying mechanism in an animal model of tGCI. After intracerebroventricular (i.c.v.) injection of bFGF, functional improvement was observed, and the number of viable neurons increased in the ischemia-vulnerable hippocampal CA1 region. Apoptosis was induced after tGCI and could be attenuated by bFGF treatment via inhibition of p53 mitochondrial translocation. In addition, autophagy was activated during this process, and bFGF could inhibit activation of autophagy through the mTOR pathway. Rapamycin, an activator of autophagy, was utilized to explore the relationship among bFGF, apoptosis, and autophagy. Apoptosis deteriorated after rapamycin treatment, which indicated that excessive autophagy could contribute to the apoptosis process. In conclusion, these results demonstrate that bFGF could exert neuroprotective effects in the hippocampal CA1 region by suppressing excessive autophagy via the mTOR pathway and inhibiting apoptosis by preventing p53 mitochondrial translocation. Furthermore, our results suggest that bFGF may be a promising therapeutic agent to for treating tGCI in response to major adverse events, including cardiac arrest, shock, extracorporeal circulation, traumatic hemorrhage, and asphyxiation.

Dl-3-n-butylphthalide prevents the disruption of blood-spinal cord barrier via inhibiting endoplasmic reticulum stress following spinal cord injury

After spinal cord injury (SCI), the destruction of blood-spinal cord barrier (BSCB) is shown to accelerate gathering of noxious blood-derived components in the nervous system, leading to secondary neurodegenerative damages. SCI activates endoplasmic reticulum stress (ER stress), which is considered to evoke secondary damages of neurons and glia. Recent evidence indicates that Dl-3-n-butylphthalide (NBP) has the neuroprotective effect in ischaemic brain injury, but whether it has protective effects on SCI or not is largely unclear. Here, we show that NBP prevented BSCB disruption after SCI via inhibition of ER stress. Following a moderate contusion injury of the T9 level of spinal cord, NBP was administered by oral gavage and further treated once a day. NBP significantly attenuated BSCB permeability and breakdown of adherens junction (AJ) and tight junction (TJ) proteins, then improved locomotion recovery following SCI. The protective role of NBP on BSCB disruption is associated with the restrain of ER stress caused by SCI. Furthermore, NBP considerably constrained the expression of ER stress-associated proteins and degradation of TJ and AJ in human brain microvascular endothelial cells (HBMECs) treated with TG. In conclusion, our results indicate that ER stress is associated with the disruption of BSCB integrity after injury, NBP attenuates BSCB disruption via inhibiting ER stress and improve functional recovery following SCI.

Fibroblast growth factors in the management of spinal cord injury

Spinal cord injury (SCI) possesses a significant health and economic burden worldwide. Traumatic SCI is a devastating condition that evolves through two successive stages. Throughout each of these stages, disturbances in ionic homeostasis, local oedema, ischaemia, focal haemorrhage, free radicals stress and inflammatory response were observed. Although there are no fully restorative cures available for SCI patients, various molecular, cellular and rehabilitative therapies, such as limiting local inflammation, preventing secondary cell death and enhancing the plasticity of local circuits in the spinal cord, were described. Current preclinical studies have showed that fibroblast growth factors (FGFs) alone or combination therapies utilizing cell transplantation and biomaterial scaffolds are proven effective for treating SCI in animal models. More importantly, some studies further demonstrated a paucity of clinical transfer usage to promote functional recovery of numerous patients with SCI. In this review, we focus on the therapeutic capacity and pitfalls of the FGF family and its clinical application for treating SCI, including the signalling component of the FGF pathway and the role in the central nervous system, the pathophysiology of SCI and the targets for FGF treatment. We also discuss the challenges and potential for the clinical translation of FGF-based approaches into treatments for SCI.

FGF2 Attenuates Neural Cell Death via Suppressing Autophagy after Rat Mild Traumatic Brain Injury

Traumatic brain injury (TBI) can lead to physical and cognitive deficits, which are caused by the secondary injury process. Effective pharmacotherapies for TBI patients are still lacking. Fibroblast growth factor-2 (FGF2) is an important neurotrophic factor that can stimulate neurogenesis and angiogenesis and has been shown to have neuroprotective effects after brain insults. Previous studies indicated that FGF2's neuroprotective effects might be related to its function of regulating autophagy. The present study investigated FGF2's beneficial effects in the early stage of rat mild TBI and the underlying mechanisms. One hundred and forty-four rats were used for creating controlled cortical impact (CCI) models to simulate the pathological damage after TBI. Our results indicated that pretreatment of FGF2 played a neuroprotective role in the early stage of rat mild TBI through alleviating brain edema, reducing neurological deficits, preventing tissue loss, and increasing the number of surviving neurons in injured cortex and the ipsilateral hippocampus. FGF2 could also protect cells from various forms of death such as apoptosis or necrosis through inhibition of autophagy. Finally, autophagy activator rapamycin could abolish the protective effects of FGF2. This study extended our understanding of FGF2's neuroprotective effects and shed lights on the pharmacological therapy after TBI.

Fibroblast growth factor 2 induces proliferation and distribution of G2 /M phase of bovine endometrial cells involving activation of PI3K/AKT and MAPK cell signaling and prevention of effects of ER stress

Fibroblast growth factor 2 (FGF2) is abundantly expressed in conceptuses and endometria during pregnancy in diverse animal models including domestic animals. However, its intracellular mechanism of action has not been reported for bovine endometrial cells. Therefore, the aim of this study was to identify functional roles of FGF2 in bovine endometrial (BEND) cell line which has served as a good model system for investigating regulation of signal transduction following treatment with interferon-tau (IFNT) in vitro. Results of present study demonstrated that administration of FGF2 to BEND cells increased their proliferation and regulated the cell cycle through DNA replication by an increase of PCNA and Cyclin D1. FGF2 also increased phosphorylation of AKT, P70S6K, S6, ERK1/2, JNK, and P38 in BEND cells in a dose-dependent manner, and expression of each of those transcription factors was inhibited by their respective pharmacological inhibitor including Wormannin, U0126, and SP600125. In addition, the increase in proliferation of BEND cells and activation of the protein kinases in response to FGF2 was suppressed by BGJ398, a FGFR inhibitor. Furthermore, proliferation of BEND cells was inhibited by tunicamycin, but treatment of BEND cells with FGF2 restored proliferation of BEND cells. Consistent with this result, the stimulated unfolded protein response (UPR) regulatory proteins induced by tunicamycin were down-regulated by FGF2. Results of this study suggest that FGF2 promotes proliferation of BEND cells and likely enhances uterine capacity and maintenance of pregnancy by activating cell signaling via the PI3K and MAPK pathways and by restoring ER stress through the FGFR.

NGF Attenuates High Glucose-Induced ER Stress, Preventing Schwann Cell Apoptosis by Activating the PI3K/Akt/GSK3β and ERK1/2 Pathways

Diabetic peripheral neuropathy (DPN) is one of the most common and troublesome complications of diabetes mellitus. It has been demonstrated that nerve growth factor (NGF) exerts a pivotal role in the regulation of neuronal growth and the promotion of DPN recovery. However, the exact molecular mechanisms are not well understood. Recent studies have indicated that as a novel therapeutic target, endoplasmic reticulum (ER) stress participates in the onset and progression of DPN. In the present study, it has been demonstrated that NGF prevents the sciatic nerve from degeneration and demyelination in DPN rats. Thus, RSC 96 cells, which retain the characteristic features of Schwann cells (SCs), were cultured in medium containing 30 mM glucose (high glucose, HG) to mimic SCs in DPN mice. The 50-ng/ml dose of NGF was identified to be the optimal concentration for treating an excessive ER stress level under HG conditions for 24 h. We found that NGF treatment significantly inhibits HG-induced ER stress and subsequently suppresses ER-related apoptosis. Further, NGF administration also activates the upstream signaling pathway of ER stress, PI3K/Akt/GSK3β signaling and ERK1/2 signaling. Co-treatment with the PI3K inhibitor LY294002 or ERK1/2 inhibitor U0126 significantly reverses the protective role of NGF on HG-induced excessive ER stress and subsequent apoptosis. These observations suggest that the neuroprotective role of NGF in DPN is mediated by the inhibition of excessive ER stress via the activation of the PI3K/Akt/GSK3β and ERK1/2 signaling pathways.

Dihydrocapsaicin (DHC) enhances the hypothermia-induced neuroprotection following ischemic stroke via PI3K/Akt regulation in rat

OBJECTIVE

Hypothermia has demonstrated neuroprotection following ischemia in preclinical studies while its clinical application is still very limited. The aim of this study was to explore whether combining local hypothermia in ischemic territory achieved by intra-arterial cold infusions (IACIs) with pharmacologically induced hypothermia enhances therapeutic outcomes, as well as the underlying mechanism.

METHODS

Sprague-Dawley rats were subjected to right middle cerebral artery occlusion (MCAO) for 2h using intraluminal hollow filament. The ischemic rats were randomized to receive: 1) pharmacological hypothermia by intraperitoneal (i.p.) injection of dihydrocapsaicin (DHC); 2) physical hypothermia by IACIs for 10min; or 3) the combined treatments. Extent of brain injury was determined by neurological deficit, infarct volume, and apoptotic cell death at 24h and/or 7d following reperfusion. ATP and ROS levels were measured. Expression of p-Akt, cleaved Caspase-3, pro-apoptotic (AIF, Bax) and anti-apoptotic proteins (Bcl-2, Bcl-xL) was evaluated at 24h. Finally, PI3K inhibitor was used to determine the effect of p-Akt.

RESULTS

DHC or IACIs each exhibited hypothermic effect and neuroprotection in rat MCAO models. The combination of pharmacological and physical approaches led to a faster and sustained reduction in brain temperatures and improved ischemia-induced injury than either alone (P<0.01). Furthermore, the combination treatment favorably increased the expression of anti-apoptotic proteins and decreased pro-apoptotic protein levels (P<0.01 or 0.05). This neuroprotective effect was largely blocked by p-Akt inhibition, indicating a potential role of Akt pathway in this mechanism (P<0.01 or 0.05).

CONCLUSIONS

The combination approach is able to enhance the efficiency of hypothermia and efficacy of hypothermia-induced neuroprotection following ischemic stroke. The findings here move us a step closer towards translating this long recognized TH from bench to bedside.

Fibroblast growth factor 2 protects against renal ischaemia/reperfusion injury by attenuating mitochondrial damage and proinflammatory signalling

Ischaemia‐reperfusion injury (I/RI) is a common cause of acute kidney injury (AKI). The molecular basis underlying I/RI‐induced renal pathogenesis and measures to prevent or reverse this pathologic process remains to be resolved. Basic fibroblast growth factor (FGF2) is reported to have protective roles of myocardial infarction as well as in several other I/R related disorders. Herein we present evidence that FGF2 exhibits robust protective effect against renal histological and functional damages in a rat I/RI model. FGF2 treatment greatly alleviated I/R‐induced acute renal dysfunction and largely blunted I/R‐induced elevation in serum creatinine and blood urea nitrogen, and also the number of TUNEL‐positive tubular cells in the kidney. Mechanistically, FGF2 substantially ameliorated renal I/RI by mitigating several mitochondria damaging parameters including pro‐apoptotic alteration of Bcl2/Bax expression, caspase‐3 activation, loss of mitochondrial membrane potential and K_ATP channel integrity. Of note, the protective effect of FGF2 was significantly compromised by the K_ATP channel blocker 5‐HD. Interestingly, I/RI alone resulted in mild activation of FGFR, whereas FGF2 treatment led to more robust receptor activation. More significantly, post‐I/RI administration of FGF2 also exhibited robust protection against I/RI by reducing cell apoptosis, inhibiting the release of damage‐associated molecular pattern molecule HMBG1 and activation of its downstream inflammatory cytokines such as IL‐1α, IL‐6 and TNF α. Taken together, our data suggest that FGF2 offers effective protection against I/RI and improves animal survival by attenuating mitochondrial damage and HMGB1‐mediated inflammatory response. Therefore, FGF2 has the potential to be used for the prevention and treatment of I/RI‐induced AKI.

Neural stem/progenitor cells on collagen with anchored basic fibroblast growth factor as potential natural nerve conduits for facial nerve regeneration

Introducing neural stem/progenitor cells (NS/PCs) for repairing facial nerve injuries could be an alternative strategy for nerve gap reconstruction. However, the lack of success associated with current methods of applying NS/PCs to neurological disease is due to poor engraftment following transplantation into the host tissue. In this work, we developed rat-tail collagen-based nerve conduits to repair lengthy facial nerve defects, promoting NS/PC proliferation in the natural nerve conduits with anchored bFGF to improve the therapeutic effects of cell transplantation. In vitro studies showed that heparinized collagen prevented leakage of bFGF and NS/PCs expended in the rat-tail collagen gel with the anchored bFGF. The natural nerve conduits were implanted to connect 8-mm facial nerve defects in rats. The repair outcomes including vibrissae movements, electrophysiological tests, immunohistochemistry and remyelination analysis of regenerated nerve were evaluated. At 12weeks after implantation, only natural nerve conduits treated group showed Hoechst labeled NS/PCs. Besides, the natural nerve conduit significantly promoted functional recovery and nerve growth, which was similar to those of the gold standard, an autograft. The animal experiment results suggesting that the natural nerve conduits were valuable for facial nerve reconstruction.

STATEMENT OF SIGNIFICANCE

Neural stem/progenitor cells (NS/PCs) were beneficial for the treatment of nervous system diseases. However, after transplantation, the beneficial was limited because the number of living NS/PCs decreased rapidly due to insufficient signaling molecules, such as growth factors, in the microenvironments surrounding transplanted cells. In the present study, we constructed collagen-based nerve conduit with anchored bFGF to achieve higher numbers of NS/PCs for repairing facial nerve injury. Compared with other methods involving neutral salt treatment or dialysis, the fabrication method of collagen scaffolds was simple, low-cost and safe, requiring a relatively short time to prepare. At 12weeks after transplantation, the functional and histological results of natural nerve conduits treated group showed significant similarities to the gold standard method of nerve autografting.

4-PBA inhibits LPS-induced inflammation through regulating ER stress and autophagy in acute lung injury models

Acute lung injury (ALI) is a common clinical disorder that causes substantial health problems worldwide. An excessive inflammatory response is the central feature of ALI, but the mechanism is still unclear, especially the role of endoplasmic-reticulum (ER) stress and autophagy. To identify the cellular mechanism of lung inflammation during lipopolysaccharide (LPS)-induced mouse model of ALI, we investigated the influence of classic ER stress inhibitor 4-phenyl butyric acid (4-PBA) on ER stress and autophagy, which partially affect the activation of inflammation, both in LPS-induced ALI mouse model and human alveolar epithelial cell model. We demonstrated that 4-PBA, which further prevented the activation of the NF-κB pathway, decreased the release of the pro-inflammatory mediators IL-1β, TNF-α and IL-6, significantly inhibited LPS-activated ER stress. Moreover, it was found that autophagy was also decreased by the treatment of 4-PBA, which may play a protective role in ALI models through the classical AKT/mTOR signaling pathway. Inhibition of autophagy by 3-MA exacerbates cytotoxicity induced by LPS in A549 alveolar epithelial cells. Taken together, our study indicated that ER stress is a key promoter in the induction of inflammation by LPS, the protective effect of 4-PBA is related to the inhibition of ER stress and autophagy in LPS-induced ALI models. Furthermore, the role of autophagy that contributes to cell survival may depend on the activation of ER stress.