Dataset Information

Tat-haFGF_14-154 Upregulates ADAM10 to Attenuate the Alzheimer Phenotype of APP/PS1 Mice through the PI3K-CREB-IRE1α/XBP1 Pathway.

ABSTRACT: Acid fibroblast growth factor (aFGF) has shown neuroprotection in Alzheimer's disease (AD) models in previous studies, yet its mechanism is still uncertain. Here we report that the efficacy of Tat-haFGF_14-154 is markedly increased when loaded cationic liposomes for intranasal delivery are intranasally administered to APP/PS1 mice. Our results demonstrated that liposomal Tat-haFGF_14-154 treatment significantly ameliorated behavioral deficits, relieved brain Aβ burden, and increased the expression and activity of disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) in the brain. Tat-haFGF_14-154 antagonized Aβ_1-42-induced cell death and structural damage in rat primary neurons in an ADAM10-dependent manner, which, in turn, was promoted by the activation of XBP1 splicing and modulated by the PI3K-CREB pathway. Both knockdown of ADAM10 and inhibition of PI3K (LY294002) negated Tat-haFGF_14-154 rescue. Thus, Tat-haFGF_14-154 activates the IRE1α/XBP1 pathway of the unfolded protein response (UPR) against the endoplasmic reticulum (ER) stress induced by Aβ, and, subsequently, the nuclear translocation of spliced XBP1 (XBP1s) promotes transcription of ADAM10. These results highlight the important role of ADAM10 and its activation through the PI3K-CREB-IRE1α/XBP1 pathway as a key factor in the mechanism of neuroprotection for Tat-haFGF_14-154.

SUBMITTER: Meng T

PROVIDER: S-EPMC5443968 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Tat-haFGF14-154 Upregulates ADAM10 to Attenuate the Alzheimer Phenotype of APP/PS1 Mice through the PI3K-CREB-IRE1α/XBP1 Pathway.

Meng Tian T Cao Qin Q Lei Peng P Bush Ashley I AI Xiang Qi Q Su Zhijian Z He Xiang X Rogers Jack T JT Chiu Ing-Ming IM Zhang Qihao Q Huang Yadong Y

Molecular therapy. Nucleic acids 20170510

Acid fibroblast growth factor (aFGF) has shown neuroprotection in Alzheimer's disease (AD) models in previous studies, yet its mechanism is still uncertain. Here we report that the efficacy of Tat-haFGF14-154 is markedly increased when loaded cationic liposomes for intranasal delivery are intranasally administered to APP/PS1 mice. Our results demonstrated that liposomal Tat-haFGF14-154 treatment significantly ameliorated behavioral deficits, relieved brain Aβ burden, and in ...[more]

PMID: 28624220

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Project description:Background: aFGF content in serum and cerebrospinal fluid is increased in Alzheimer's disease (AD) patients and attenuates the activation of astrocytes. Extracellular vesicles (EVs) are a major mediator in astrocyte-neuron communications. Since excessive or persistent reactive astrocytes lead to chronic inflammation and neuronal dysfunction, and the activation of astrocytes can be inhibited by aFGF, we proposed that the cargoes of astrocyte-derived EVs (AEVs) might be modified by aFGF stimulation, playing an important role in AD progression. However, the mechanisms underlying the role of aFGF remain unclear. Methods: AEVs were isolated from damaged astrocytes, treated with or without aFGF in Aβ-loading condition, and were intranasally administered to AD mice. We determined the ability of AEVs to enter the brain, ameliorate cognitive behavior deficits, alleviate the Aβ burden in the brain, and improve synapse ultrastructure. Subsequently, the miRNAs enriched in AEVs were sequenced to identify the key molecules specifically modified by aFGF. Finally, we explored the protective effects of miR-206-3p inhibition on cognitive deficiency and its regulatory mechanism and determined its role as a specific biomarker for potential AD diagnosis. Results: AEVs stimulated by aFGF (defined as AEVs-Aβ+H) had favorable neuroprotection in AD pathology by enhancing neurite growth and reduction of Aβ loading on neurons in vitro. Following intranasal administration, AEVs-Aβ+H ameliorated cognitive behavior deficits, promoted synaptic plasticity, and alleviated brain Aβ burden in the APP/PS1 and Aβ brain-injected mice. AEVs-Aβ+H showed beneficial effects on AD similar to AEVs produced in normal situations (AEVs-Ctrl). aFGF stimulation modified the cargoes in EVs derived from Aβ damaged astrocytes, the most significant of which being the down-regulation of miR-206-3p. The miR-206-3p level was specifically high in the plasma of AD mice and patients, and miR-206-3p antagomir reversed the Alzheimer phenotype in AD mice. The brain-derived neurotrophic factor (BDNF) gene was negatively regulated by miR-206-3p and upregulated by AEVs-Aβ+H and miR-206-3p antagomir in AD mice. AEVs-Aβ+H inhibited δ-secretase (Asparagine endopeptidase, AEP) activation via the miR-206-3p/BDNF axis to alleviate Aβ burden in the AD brain. Conclusion: Our findings highlight the role of aFGF in the modification of AEVs cargoes, especially miR-206-3p that can potentially serve as a biomarker for AD diagnosis and therapeutic target.

Project description:Rhabdomyosarcoma (RMS) is the most common soft-tissue sarcoma in children, and is associated with a poor prognosis in patients presenting with recurrent or metastatic disease. The unfolded protein response (UPR) plays pivotal roles in tumor development and resistance to therapy, including RMS. In this study, we used immunohistochemistry and a tissue microarray (TMA) on human RMS and normal skeletal muscle to evaluate the expression of key UPR proteins (GRP78/BiP, IRE1α and cytosolic/nuclear XBP1 (spliced XBP1-sXBP1)) in the four main RMS subtypes: alveolar (ARMS), embryonal (ERMS), pleomorphic (PRMS) and sclerosing/spindle cell (SRMS) RMS. We also investigated the correlation of these proteins with the risk of RMS and several clinicopathological indices, such as lymph node involvement, distant metastasis, tumor stage and tumor scores. Our results revealed that the expression of BiP, sXBP1, and IRE1α, but not cytosolic XBP1, are significantly associated with RMS (BiP and sXBP1 p-value = 0.0001, IRE1 p-value = 0.001) in all of the studied types of RMS tumors (n = 192) compared to normal skeletal muscle tissues (n = 16). In addition, significant correlations of BiP with the lymph node score (p = 0.05), and of IRE1α (p value = 0.004), cytosolic XBP1 (p = 0.001) and sXBP1 (p value = 0.001) with the stage score were observed. At the subtype level, BiP and sXBP1 expression were significantly associated with all subtypes of RMS, whereas IRE1α was associated with ARMS, PRMS and ERMS, and cytosolic XBP1 expression was associated with ARMS and SRMS. Importantly, the expression levels of IRE1α and sXBP1 were more pronounced in ARMS than in any of the other subtypes. The results also showed correlations of BiP with the lymph node score in ARMS (p value = 0.05), and of sXBP1 with the tumor score in PRMS (p value = 0.002). In summary, this study demonstrates that the overall UPR is upregulated and, more specifically, that the IRE1/sXBP1 axis is active in RMS. The subtype and stage-specific dependency on the UPR machinery in RMS may open new avenues for the development of novel targeted therapeutic strategies and the identification of specific tumor markers in this rare but deadly childhood and young-adult disease.

Project description:The cellular processes that support human coronavirus replication and contribute to the pathogenesis of severe disease remain incompletely understood. Many viruses, including coronaviruses, cause endoplasmic reticulum (ER) stress during infection. IRE1α is a component of the cellular response to ER stress that initiates non-conventional splicing of XBP1 mRNA. Spliced XBP1 encodes a transcription factor that induces the expression of ER-related targets. Activation of the IRE1α-XBP1 pathway occurs in association with risk factors for severe human coronavirus infection. In this study, we found that the human coronaviruses HCoV-OC43 (human coronavirus OC43) and SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) both robustly activate the IRE1α-XBP1 branch of the unfolded protein response in cultured cells. Using IRE1α nuclease inhibitors and genetic knockdown of IRE1α and XBP1, we found that these host factors are required for optimal replication of both viruses. Our data suggest that IRE1α supports infection downstream of initial viral attachment and entry. In addition, we found that ER stress-inducing conditions are sufficient to enhance human coronavirus replication. Furthermore, we found markedly increased XBP1 in circulation in human patients with severe coronavirus disease 2019 (COVID-19). Together, these results demonstrate the importance of IRE1α and XBP1 for human coronavirus infection. IMPORTANCE There is a critical need to understand the cellular processes co-opted during human coronavirus replication, with an emphasis on identifying mechanisms underlying severe disease and potential therapeutic targets. Here, we demonstrate that the host proteins IRE1α and XBP1 are required for robust infection by the human coronaviruses, SARS-CoV-2 and HCoV-OC43. IRE1α and XBP1 participate in the cellular response to ER stress and are activated during conditions that predispose to severe COVID-19. We found enhanced viral replication with exogenous IRE1α activation, and evidence that this pathway is activated in humans during severe COVID-19. Together, these results demonstrate the importance of IRE1α and XBP1 for human coronavirus infection.

Dataset Information

Tat-haFGF_14-154 Upregulates ADAM10 to Attenuate the Alzheimer Phenotype of APP/PS1 Mice through the PI3K-CREB-IRE1α/XBP1 Pathway.

Publications

Tat-haFGF<sub>14-154</sub> Upregulates ADAM10 to Attenuate the Alzheimer Phenotype of APP/PS1 Mice through the PI3K-CREB-IRE1α/XBP1 Pathway.

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