scholarly journals AngIV-Analog Dihexa Rescues Cognitive Impairment and Recovers Memory in the APP/PS1 Mouse via the PI3K/AKT Signaling Pathway

2021 ◽  
Vol 11 (11) ◽  
pp. 1487
Author(s):  
Xiaojin Sun ◽  
Yang Deng ◽  
Xinxin Fu ◽  
Siyu Wang ◽  
Rui Duan ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Signaling Pathway ◽  
Renin Angiotensin System ◽  
Akt Signaling ◽  
Mouse Tissue ◽  
Morris Water Maze Test ◽  
Akt Signaling Pathway ◽  
Nissl Staining ◽  
Anti Inflammatory ◽  
The Brain

The renin-angiotensin system (RAS) is a paracrine RAS within the central nervous system (CNS) and is closely related to Alzheimer’s disease (AD). The endogenous hexapeptide angiotensin IV (Ang IV), an important component of the brain RAS, was found to rescue cognitive impairment and recover memory in previous studies. In our study, we used different doses of Dihexa, which can be orally administered and cross the BBB in APP/PS1 mice. We found that the amount of AngIV in mouse tissue increased after the administration of Dihexa compared to that in the WT group. Meanwhile, Dihexa restored spatial learning and cognitive functions in the Morris water maze test. Dihexa increased the neuronal cells and the expression of SYP protein in APP/PS1 mice in Nissl staining. Furthermore, Dihexa decreased the activation of astrocytes and microglia, markedly reduced levels of the pro-inflammatory cytokines IL-1β and TNF-α and increased the levels of the anti-inflammatory cytokine IL-10. Dihexa activated the PI3K/AKT signaling pathway, while PI3K inhibitor wortmannin significantly reversed the anti-inflammatory and anti-apoptotic effects of APP/PS1 mice. These findings highlight the brain AngIV/PI3K/AKT axis as a potential target for the treatment of AD.

scholarly journals Thyroid hormone mediates cardioprotection against postinfarction remodeling and dysfunction through the IGF-1/PI3K/AKT signaling pathway

2020 ◽  
Author(s):  
Bin Zeng ◽  
Xiaoting Liao ◽  
Lei Liu ◽  
Caixia Zhang ◽  
Huaiyu Ruan
Keyword(s):  
Myocardial Infarction ◽  
Cardiovascular Diseases ◽  
Thyroid Hormone ◽  
Signaling Pathway ◽  
Akt Signaling ◽  
Left Ventricular ◽  
Sham Operation ◽  
Akt Signaling Pathway ◽  
Anti Inflammatory ◽  
Related Proteins

Abstract Background Severe cardiovascular diseases, such as myocardial infarction or heart failure, can alter thyroid hormone (TH) secretion and peripheral conversion, leading to low triiodothyronine (T3) syndrome. Accumulating evidence suggests that TH has protective properties against cardiovascular diseases and that treatment with TH can effectively reduce myocardial damage after myocardial infarction (MI). However, the potential mechanisms are not clear. This study was designed to investigate the effect of T3 pretreatment on cardiac function and pathological changes in mice subjected to MI and the underlying mechanisms. Methods Adult male C57BL/6 mice underwent surgical ligation of the left anterior descending coronary artery (LAD) (or sham operation) to establish a myocardial infarction model. T3, BMS-754807 (inhibitor of insulin-like growth factor-1 receptor (IGF-1R)) or vehicle was administered before surgery. Results Compared with the MI group, the T3 pretreatment group exhibited significant attenuation of the myocardial infarct area, inhibition of cardiomyocyte apoptosis and fibrosis, and improved left ventricular function after MI. In addition, T3 exhibited an enhanced potency to stimulate angiogenesis and exert anti-inflammatory effects by reducing the levels of serum inflammatory cytokines after myocardial infarction. However, all of these protective effects were inhibited by the IGF-1R inhibitor BMS-754807. Moreover, the protein expression of IGF-1/PI3K/AKT signaling-related proteins, such as IGF-1, IGF-1R, phosphorylated PI3K (p-PI3K) and p-AKT was significantly upregulated in MI mice that received T3 pretreatment, and BMS-754807 pretreatment blocked the upregulation of the expression of these signaling-related proteins. Conclusion T3 pretreatment can protect the heart against dysfunction post-MI through its anti-apoptotic, anti-fibrotic, anti-inflammatory and angiogenesis-stimulating effects, which may be mediated by the activation of the IGF-1/PI3K/AKT signaling pathway.

scholarly journals Astrocyte-Derived Transforming Growth Factor-β Mediates the Neuroprotective Effects of 17β-Estradiol: Involvement of Nonclassical Genomic Signaling Pathways

Endocrinology ◽  
2005 ◽  
Vol 146 (6) ◽  
pp. 2749-2759 ◽  
Author(s):  
Krishnan M. Dhandapani ◽  
F. Marlene Wade ◽  
Virendra B. Mahesh ◽  
Darrell W. Brann
Keyword(s):  
Estrogen Receptor ◽  
Signaling Pathway ◽  
Transforming Growth Factor ◽  
Neuronal Cell ◽  
Akt Signaling ◽  
Akt Signaling Pathway ◽  
Cortical Astrocytes ◽  
Cortical Astrocyte ◽  
17Β Estradiol ◽  
The Brain

Abstract 17β-Estradiol (E2) and selective estrogen receptor modulators (SERMs), such as tamoxifen, mediate numerous effects in the brain, including neurosecretion, neuroprotection, and the induction of synaptic plasticity. Astrocytes, the most abundant cell type in the brain, influence many of these same functions and thus may represent a mediator of estrogen action. The present study examined the regulatory effect and underlying cell signaling mechanisms of E2-induced release of neurotropic growth factors from primary rat cortical astrocyte cultures. The results revealed that E2 (0.5, 1, and 10 nm) and tamoxifen (1 μm) increased both the expression and release of the neuroprotective cytokines, TGF-β1 and TGF-β2 (TGF-β), from cortical astrocytes. The stimulatory effect of E2 was attenuated by the estrogen receptor (ER) antagonist, ICI182,780, suggesting ER dependency. The effect of E2 also appeared to involve mediation by the phosphotidylinositol 3-kinase (PI3K)/Akt signaling pathway, because E2 rapidly induced Akt phosphorylation, and pharmacological or molecular inhibition of the PI3K/Akt pathway prevented E2-induced release of TGF-β. Additionally, the membrane-impermeant conjugate, E2-BSA, stimulated the release of TGF-β, suggesting the potential involvement of a membrane-bound ER. Finally, E2, tamoxifen, and E2-BSA were shown to protect neuronal-astrocyte cocultures from camptothecin-induced neuronal cell death, effects that were attenuated by ICI182,780, Akt inhibition, or TGF-β immunoneutralization. As a whole, these studies suggest that E2 induction of TGF-β release from cortical astrocytes could provide a mechanism of neuroprotection, and that E2 stimulation of TGF-β expression and release from astrocytes occurs via an ER-dependent mechanism involving mediation by the PI3K/Akt signaling pathway.

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