Agonistic analog of growth hormone–releasing hormone promotes neurofunctional recovery and neural regeneration in ischemic stroke

2021 ◽  
Vol 118 (47) ◽  
pp. e2109600118
Author(s):  
Yueyang Liu ◽  
Jingyu Yang ◽  
Xiaohang Che ◽  
Jianhua Huang ◽  
Xianyang Zhang ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Ischemic Stroke ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Term Treatment ◽  
Neural Regeneration ◽  
Growth Hormone Releasing Hormone ◽  
Neuroprotective Effects ◽  
Releasing Hormone ◽  
Long Term Treatment

Ischemic stroke can induce neurogenesis. However, most stroke-generated newborn neurons cannot survive. It has been shown that MR-409, a potent synthetic agonistic analog of growth hormone–releasing hormone (GHRH), can protect against some life-threatening pathological conditions by promoting cell proliferation and survival. The present study shows that long-term treatment with MR-409 (5 or 10 μg/mouse/d) by subcutaneous (s.c.) injection significantly reduces the mortality, ischemic insult, and hippocampal atrophy, and improves neurological functional recovery in mice operated on for transient middle cerebral artery occlusion (tMCAO). Besides, MR-409 can stimulate endogenous neurogenesis and improve the tMCAO-induced loss of neuroplasticity. MR-409 also enhances the proliferation and inhibits apoptosis of neural stem cells treated with oxygen and glucose deprivation–reperfusion. The neuroprotective effects of MR-409 are closely related to the activation of AKT/CREB and BDNF/TrkB pathways. In conclusion, the present study demonstrates that GHRH agonist MR-409 has remarkable neuroprotective effects through enhancing endogenous neurogenesis in cerebral ischemic mice.

scholarly journals Ras-like Gem GTPase induced by Npas4 promotes activity-dependent neuronal tolerance for ischemic stroke

2021 ◽  
Vol 118 (32) ◽  
pp. e2018850118
Author(s):  
Hiroo Takahashi ◽  
Ryo Asahina ◽  
Masayuki Fujioka ◽  
Takeshi K. Matsui ◽  
Shigeki Kato ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cortical Neurons ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Small Gtpase ◽  
Neuroprotective Effects ◽  
Necessary And Sufficient ◽  
Activity Dependent

Ischemic stroke, which results in loss of neurological function, initiates a complex cascade of pathological events in the brain, largely driven by excitotoxic Ca2+ influx in neurons. This leads to cortical spreading depolarization, which induces expression of genes involved in both neuronal death and survival; yet, the functions of these genes remain poorly understood. Here, we profiled gene expression changes that are common to ischemia (modeled by middle cerebral artery occlusion [MCAO]) and to experience-dependent activation (modeled by exposure to an enriched environment [EE]), which also induces Ca2+ transients that trigger transcriptional programs. We found that the activity-dependent transcription factor Npas4 was up-regulated under MCAO and EE conditions and that transient activation of cortical neurons in the healthy brain by the EE decreased cell death after stroke. Furthermore, both MCAO in vivo and oxygen-glucose deprivation in vitro revealed that Npas4 is necessary and sufficient for neuroprotection. We also found that this protection involves the inhibition of L-type voltage-gated Ca2+ channels (VGCCs). Next, our systematic search for Npas4-downstream genes identified Gem, which encodes a Ras-related small GTPase that mediates neuroprotective effects of Npas4. Gem suppresses the membrane localization of L-type VGCCs to inhibit excess Ca2+ influx, thereby protecting neurons from excitotoxic death after in vitro and in vivo ischemia. Collectively, our findings indicate that Gem expression via Npas4 is necessary and sufficient to promote neuroprotection in the injured brain. Importantly, Gem is also induced in human cerebral organoids cultured under an ischemic condition, revealing Gem as a new target for drug discovery.

Neuroprotective Effects of microRNA-140-5p on Ischemic Stroke in Mice via its Regulation on the TLR4/NF-κB Axis

2020 ◽  
Author(s):  
Song Wenjun ◽  
Tiancheng Wang ◽  
Bei Shi ◽  
Zhijun Wu ◽  
Wenjie Wang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Luciferase Reporter ◽  
Tunel Staining ◽  
Related Factors ◽  
Neuroprotective Effects ◽  
High Level

Abstract Background and aim: Ischemic stroke is one of the main causes of death worldwide and permanent global disability. On the basis of existing literature data, we carried out studies in an effort to explore how miR-140-5p affects ischemic stroke and whether the mechanism relates to toll-like receptor-4 (TLR4) and nuclear factor-kappa B (NF-κB).Methods: Middle cerebral artery occlusion (MCAO) was employed to establish a mouse model of ischemic stroke in vivo, while primary neurons were exposed to oxygen-glucose deprivation (OGD) to set up an ischemic stroke model in vitro. RT-qPCR was performed to detect the miR-140-5p expression and Western blot was employed to detect the expression TLR4, NF-κB, and apoptosis-related factors. Then, based gain-function of experiments using miR-140-5p mimic and TLR4 overexpression plasmid, neurological function score, TTC staining, TUNEL staining, as well as flow cytometry were carried out to evaluate the effects of miR-140-5p and TLR4 on MCAO mice and OGD neurons. Meanwhile, dual-luciferase reporter assay was used to validate the relationship between miR-140-5p and TLR4.Results: miR-140-5p expressed at a low level and TLR4 at a high level in ischemic stroke. It was verified that miR-140-5p targeted TLR4 and downregulated its expression. miR-140-5p overexpression was observed to inhibit the apoptosis of neurons under OGD exposure and restrain the progression of ischemic stroke, while TLR4 overexpression promoted the apoptosis and disease progression. Besides, miR-140-5p overexpression led to a decrease in NF-κB protein level, which was increased by TLR4 overexpression. Conclusion: In conclusion, from our data we conclude that miR-140-5p overexpression may be instrumental for the therapeutic targeting of ischemic stroke by alleviating neuron injury with the involvement of TLR4/NF-κB axis.

scholarly journals Design, Synthesis and Biological Evaluation of Indoline Derivatives as Multifunctional Agents for the Treatment of Ischemic Stroke

2021 ◽  
Author(s):  
Shuaishuai Du ◽  
Fan Jin ◽  
Jiaming Li ◽  
Xiaodong Ma ◽  
Hongwei Wang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Neuronal Damage ◽  
Glucose Deprivation ◽  
Biological Evaluation ◽  
Artery Occlusion ◽  
Raw 264.7 Cells ◽  
Protective Effects ◽  
Neuroprotective Agents ◽  
Neuroprotective Effects ◽  
Design Synthesis

Abstract In this work, a series of indoline derivatives as multifunctional neuroprotective agents for battling ischemic stroke were designed, synthesized, and biologically evaluated. In antioxidant assay, all compounds showed significant protective effects against H2O2-induced death of RAW 264.7 cells. In oxygen glucose deprivation/reperfusion (OGD/R)-induced neuronal damage, some compounds significantly elevated the cell survival rate. Among them, 7i, 7j and 7r exerted comparable neuroprotective effects to Ifenprodil, and exhibited binding affinity to N-methyl-D-aspartic acid receptors 2B (NMDA-GluN2B). At the concentrations of 0.1, 1 and 10 μM, 7i, 7j and 7r dose-dependently lowered the LPS-induced secretion of inflammatory cytokines, including TNF-α, IL-6 and NO, by BV-2 cells. Importantly, 7i and 7j can dramatically reduce the cerebral infarction rate and improve neurological deficit scores in middle cerebral artery occlusion (MCAO) rat model. As demonstrated by the above results, 7i and 7j are potential neuroprotective agents for the treatment of ischemic stroke.

scholarly journals Postischemic Long-Term Treatment with Qiangli Tianma Duzhong Capsule Improves Brain Functional Recovery via the Improvement of Hemorrheology and the Inhibition of Platelet Aggregation in a Rat Model of Focal Cerebral Ischemia

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Li-Zhi Hong ◽  
Wei-wei Gu ◽  
Yong Ni ◽  
Min Xu ◽  
Lei Yang ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Platelet Aggregation ◽  
Neurological Outcome ◽  
Focal Cerebral Ischemia ◽  
Artery Occlusion ◽  
Term Treatment ◽  
Tissue Loss ◽  
Inhibition Of Platelet Aggregation ◽  
Long Term Treatment

Qiangli Tianma Duzhong capsule (TMDZ), a Chinese herbal drug, is clinically used to improve functional outcome in patients with ischemic stroke in China. This study was conducted to establish whether postischemic long-term treatment with TMDZ could reduce the loss of injured hemisphere and confer the improvements of neurological outcome in chronic survival of rats with 2 h middle cerebral artery occlusion (MCAO)/reperfusion brain injury and its primary mechanisms. We found that TMDZ (44.5, 89, or 178 mg/kg), administered per os 6 h after the onset of ischemia and for 28 consecutive days, significantly improved the behavior deficits, beginning on day 7, and further improved later. TMDZ treatment also markedly reduced the tissue loss of the injured hemisphere and improved histopathology. In the meantime, TMDZ treatment could improve hemorrheology and inhibit platelet aggregation. These results provide the first evidence that post-ischemic long-term treatment with TMDZ confers the improvements of neurological outcome and the loss of injured hemisphere in an animal ischemic stroke model, and its mechanisms might be associated with the improvements of hemorrheology and the inhibition of platelet aggregation.

Association of pituitary adenoma with neuronal christoma: A TEM study

1994 ◽  
Vol 52 ◽  
pp. 232-233
Author(s):  
Eva Horvath ◽  
Kalman Kovacs ◽  
B. W. Scheithauer ◽  
R. V. Lloyd ◽  
H. S. Smyth
Keyword(s):  
Growth Hormone ◽  
Pituitary Adenoma ◽  
Pituitary Tumor ◽  
Nervous Tissue ◽  
Alternative Explanation ◽  
Growth Hormone Releasing Hormone ◽  
Cell Hyperplasia ◽  
Releasing Hormone ◽  
Secretory Neurons

The association of a pituitary adenoma with nervous tissue consisting of neuron-like cells and neuropil is a rare abnormality. In the majority of cases, the pituitary tumor is a chromophobic adenoma, accompanied by acromegaly. Histology reveals widely variable proportions of endocrine and nervous tissue in alternating or intermingled patterns. The lesion is perceived as a composite one consisting of two histogenetically distinct parts. It has been suggested that the neuronal component, morphologically similar to secretory neurons of the hypothalamus, may initiate adenoma formation by releasing stimulatory substances. Immunoreactivity for growth hormone releasing hormone (GRH) in the neuronal component of some cases supported this view, whereas other findings such as consistent lack of growth hormone (GH) cell hyperplasia in the lesions called for alternative explanation.Fifteen tumors consisting of a pituitary adenoma and a neuronal component have been collected over a 20 yr. period. Acromegaly was present in 11 patients, was equivocal in one, and absent in 3.

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