GRP78 Overexpression Triggers PINK1-IP3R-Mediated Neuroprotective Mitophagy

An experimental model of spinal root avulsion (RA) is useful to study causal molecular programs that drive retrograde neurodegeneration after neuron-target disconnection. This neurodegenerative process shares common characteristics with neuronal disease-related processes such as the presence of endoplasmic reticulum (ER) stress and autophagy flux blockage. We previously found that the overexpression of GRP78 promoted motoneuronal neuroprotection after RA. After that, we aimed to unravel the underlying mechanism by carrying out a comparative unbiased proteomic analysis and pharmacological and genetic interventions. Unexpectedly, mitochondrial factors turned out to be most altered when GRP78 was overexpressed, and the abundance of engulfed mitochondria, a hallmark of mitophagy, was also observed by electronic microscopy in RA-injured motoneurons after GRP78 overexpression. In addition, GRP78 overexpression increased LC3-mitochondria tagging, promoted PINK1 translocation, mitophagy induction, and recovered mitochondrial function in ER-stressed cells. Lastly, we found that GRP78-promoted pro-survival mitophagy was mediated by PINK1 and IP3R in our in vitro model of motoneuronal death. This data indicates a novel relationship between the GRP78 chaperone and mitophagy, opening novel therapeutical options for drug design to achieve neuroprotection.

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SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

10.1101/2020.03.06.981654 ◽

2020 ◽

Author(s):

Yuxiao Zhao ◽

Jianlong Jia ◽

Abdullah Shopit ◽

Yang Liu ◽

Jun Wang

Keyword(s):

Acute Pancreatitis ◽

In Vitro Model ◽

Autophagic Flux ◽

Trypsin Activity ◽

Autophagy Flux ◽

Trypsinogen Activation ◽

Vitro Model ◽

First Time ◽

Induced Amelioration

AbstractSPINK1 has been regarded as a reversible trypsinogen inhibitor for the inappropriate activation of trypsin, a key step in the initiation of acute pancreatitis (AP). However, the mechanisms of its action remains largely unclear and controversial. Here, we reported an unexpected effects of SPINK1 on inhibiting trypsinogen activation through the regulation of impaired autophagy in cerulein-stimulated AR42J cells, a well-established in vitro model of acute pancreatitis. Firstly, we found that the impaired autophagic flux was induced and trypsinogen activity enhanced in the above setting. Then, we showed that SPINK1 overexpression could inhibit the level of increased autophagic activity, improving the hindered autophagy flux, and significantly decreased the trypsinogen activity, whereas shRNA-caused downregulation of SPINK1 exacerbated the impairment of autophagic flux and trypsin activity, in the same cerulein-processed cells. More importantly, the trypsinogen activation in this model could be ameliorated by 3-Methyladenine(3-MA), an autophagy inhibitor. Thus, this study revealed, possibly for the first time, that SPINK1 greatly blocked the trypsinogen activation possibly through the modulation of impaired autophagy in cerulein-induced in vitro model of acute pancreatitis.

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An in vitro model for investigation of vitamin A effects on wound healing

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000692 ◽

2021 ◽

pp. 1-6

Author(s):

Hoda Keshmiri Neghab ◽

Mohammad Hasan Soheilifar ◽

Gholamreza Esmaeeli Djavid

Keyword(s):

Wound Healing ◽

Endothelial Cell ◽

Vitamin A ◽

In Vitro Model ◽

Cellular Proliferation ◽

Endothelial Cell Migration ◽

Normal Fibroblast ◽

Anti Inflammatory ◽

Vitro Model

Abstract. Wound healing consists of a series of highly orderly overlapping processes characterized by hemostasis, inflammation, proliferation, and remodeling. Prolongation or interruption in each phase can lead to delayed wound healing or a non-healing chronic wound. Vitamin A is a crucial nutrient that is most beneficial for the health of the skin. The present study was undertaken to determine the effect of vitamin A on regeneration, angiogenesis, and inflammation characteristics in an in vitro model system during wound healing. For this purpose, mouse skin normal fibroblast (L929), human umbilical vein endothelial cell (HUVEC), and monocyte/macrophage-like cell line (RAW 264.7) were considered to evaluate proliferation, angiogenesis, and anti-inﬂammatory responses, respectively. Vitamin A (0.1–5 μM) increased cellular proliferation of L929 and HUVEC (p < 0.05). Similarly, it stimulated angiogenesis by promoting endothelial cell migration up to approximately 4 fold and interestingly tube formation up to 8.5 fold (p < 0.01). Furthermore, vitamin A treatment was shown to decrease the level of nitric oxide production in a dose-dependent effect (p < 0.05), exhibiting the anti-inflammatory property of vitamin A in accelerating wound healing. These results may reveal the therapeutic potential of vitamin A in diabetic wound healing by stimulating regeneration, angiogenesis, and anti-inﬂammation responses.

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