CircTMEM165 Facilitates Vascular Endothelial Repair by Modulating Mitochondrial Fission via miR-192/SCP2 in vitro and in vivo

Background: Diabetic retinopathy (DR) is one of the most important microvascular diseases of diabetes. Our previous research demonstrated that bile acid G-protein-coupled membrane receptor (TGR5), a novel cell membrane receptor of bile acid, ameliorates the vascular endothelial cell dysfunction in DR. However, the precise mechanism leading to this alteration remains unknown. Thus, the mechanism of TGR5 in the progress of DR should be urgently explored.Methods: In this study, we established high glucose (HG)-induced human retinal vascular endothelial cells (RMECs) and streptozotocin-induced DR rat in vitro and in vivo. The expression of TGR5 was interfered through the specific agonist or siRNA to study the effect of TGR5 on the function of endothelial cell in vitro. Western blot, immunofluorescence and fluorescent probes were used to explore how TGR5 regulated mitochondrial homeostasis and related molecular mechanism. The adeno-associated virus serotype 8-shTGR5 (AAV8-shTGR5) was performed to evaluate retinal dysfunction in vivo and further confirm the role of TGR5 in DR by HE staining, TUNEL staining, PAS staining and Evans Blue dye.Results: We found that TGR5 activation alleviated HG-induced endothelial cell apoptosis by improving mitochondrial homeostasis. Additionally, TGR5 signaling reduced mitochondrial fission by suppressing the Ca2+-PKCδ/Drp1 signaling and enhanced mitophagy through the upregulation of the PINK1/Parkin signaling pathway. Furthermore, our result indicated that Drp1 inhibited mitophagy by facilitating the hexokinase (HK) 2 separation from the mitochondria and HK2-PINK1/Parkin signaling. In vivo, intraretinal microvascular abnormalities, including retinal vascular leakage, acellular capillaries and apoptosis, were poor in AAV8-shTGR5-treated group under DR, but this effect was reversed by pretreatment with the mitochondrial fission inhibitor Mdivi-1 or autophagy agonist Rapamycin.Conclusion: Overall, our findings indicated that TGR5 inhibited mitochondrial fission and enhanced mitophagy in RMECs by regulating the PKCδ/Drp1-HK2 signaling pathway. These results revealed the molecular mechanisms underlying the protective effects of TGR5 and suggested that activation of TGR5 might be a potential therapeutic strategy for DR.

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Regulation of vascular endothelial growth factor expression in human endometrium by steroids and hypoxia: In vitro and in vivo studies

Journal of the Society for Gynecologic Investigation ◽

10.1016/s1071-5576(97)86195-3 ◽

1998 ◽

Vol 5 (1) ◽

pp. 69A-69A

Author(s):

A SHARKEY ◽

D CHARNOCKJONES ◽

K DAY ◽

H SOWTER ◽

L SVENSSON ◽

...

Keyword(s):

Vascular Endothelial Growth Factor ◽

Growth Factor ◽

Human Endometrium ◽

In Vivo Studies ◽

Vascular Endothelial ◽

Factor Expression ◽

Growth Factor Expression ◽

Endothelial Growth Factor

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All-Trans Retinoic Acid Increases DRP1 Levels and Promotes Mitochondrial Fission

Cells ◽

10.3390/cells10051202 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1202

Author(s):

Bojjibabu Chidipi ◽

Syed Islamuddin Shah ◽

Michelle Reiser ◽

Manasa Kanithi ◽

Amanda Garces ◽

...

Keyword(s):

Retinoic Acid ◽

Mitochondrial Fission ◽

Normal Function ◽

Mitochondrial Network ◽

Protein Levels ◽

Trans Retinoic Acid ◽

All Trans Retinoic Acid ◽

Area And Perimeter

In the heart, mitochondrial homeostasis is critical for sustaining normal function and optimal responses to metabolic and environmental stressors. Mitochondrial fusion and fission are thought to be necessary for maintaining a robust population of mitochondria, and disruptions in mitochondrial fission and/or fusion can lead to cellular dysfunction. The dynamin-related protein (DRP1) is an important mediator of mitochondrial fission. In this study, we investigated the direct effects of the micronutrient retinoid all-trans retinoic acid (ATRA) on the mitochondrial structure in vivo and in vitro using Western blot, confocal, and transmission electron microscopy, as well as mitochondrial network quantification using stochastic modeling. Our results showed that ATRA increases DRP1 protein levels, increases the localization of DRP1 to mitochondria in isolated mitochondrial preparations. Our results also suggested that ATRA remodels the mitochondrial ultrastructure where the mitochondrial area and perimeter were decreased and the circularity was increased. Microscopically, mitochondrial network remodeling is driven by an increased rate of fission over fusion events in ATRA, as suggested by our numerical modeling. In conclusion, ATRA results in a pharmacologically mediated increase in the DRP1 protein. It also results in the modulation of cardiac mitochondria by promoting fission events, altering the mitochondrial network, and modifying the ultrastructure of mitochondria in the heart.

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Organic Nanocarriers for Bevacizumab Delivery: An Overview of Development, Characterization and Applications

Molecules ◽

10.3390/molecules26144127 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4127

Author(s):

Aline de Cristo Soares Alves ◽

Franciele Aline Bruinsmann ◽

Silvia Stanisçuaski Guterres ◽

Adriana Raffin Pohlmann

Keyword(s):

Monoclonal Antibody ◽

Physicochemical Characterization ◽

Vascular Endothelial ◽

Organic Nanoparticles ◽

Humanized Monoclonal Antibody ◽

Angiogenesis Process ◽

Endothelial Growth Factor ◽

Drug Pharmacokinetics

Bevacizumab (BCZ) is a recombinant humanized monoclonal antibody against the vascular endothelial growth factor, which is involved in the angiogenesis process. Pathologic angiogenesis is observed in several diseases including ophthalmic disorders and cancer. The multiple administrations of BCZ can cause adverse effects. In this way, the development of controlled release systems for BCZ delivery can promote the modification of drug pharmacokinetics and, consequently, decrease the dose, toxicity, and cost due to improved efficacy. This review highlights BCZ formulated in organic nanoparticles providing an overview of the physicochemical characterization and in vitro and in vivo biological evaluations. Moreover, the main advantages and limitations of the different approaches are discussed. Despite difficulties in working with antibodies, those nanocarriers provided advantages in BCZ protection against degradation guaranteeing bioactivity maintenance.

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Non-alcoholic fatty liver disease in mice with hepatocyte-specific deletion of mitochondrial fission factor

Diabetologia ◽

10.1007/s00125-021-05488-2 ◽

2021 ◽

Author(s):

Yukina Takeichi ◽

Takashi Miyazawa ◽

Shohei Sakamoto ◽

Yuki Hanada ◽

Lixiang Wang ◽

...

Keyword(s):

Er Stress ◽

Mitochondrial Dynamics ◽

Mitochondrial Fission ◽

Primary Hepatocytes ◽

Alcoholic Fatty Liver ◽

Expression Of Genes ◽

Specific Deletion

Abstract Aims/hypothesis Mitochondria are highly dynamic organelles continuously undergoing fission and fusion, referred to as mitochondrial dynamics, to adapt to nutritional demands. Evidence suggests that impaired mitochondrial dynamics leads to metabolic abnormalities such as non-alcoholic steatohepatitis (NASH) phenotypes. However, how mitochondrial dynamics are involved in the development of NASH is poorly understood. This study aimed to elucidate the role of mitochondrial fission factor (MFF) in the development of NASH. Methods We created mice with hepatocyte-specific deletion of MFF (MffLiKO). MffLiKO mice fed normal chow diet (NCD) or high-fat diet (HFD) were evaluated for metabolic variables and their livers were examined by histological analysis. To elucidate the mechanism of development of NASH, we examined the expression of genes related to endoplasmic reticulum (ER) stress and lipid metabolism, and the secretion of triacylglycerol (TG) using the liver and primary hepatocytes isolated from MffLiKO and control mice. Results MffLiKO mice showed aberrant mitochondrial morphologies with no obvious NASH phenotypes during NCD, while they developed full-blown NASH phenotypes in response to HFD. Expression of genes related to ER stress was markedly upregulated in the liver from MffLiKO mice. In addition, expression of genes related to hepatic TG secretion was downregulated, with reduced hepatic TG secretion in MffLiKO mice in vivo and in primary cultures of MFF-deficient hepatocytes in vitro. Furthermore, thapsigargin-induced ER stress suppressed TG secretion in primary hepatocytes isolated from control mice. Conclusions/interpretation We demonstrated that ablation of MFF in liver provoked ER stress and reduced hepatic TG secretion in vivo and in vitro. Moreover, MffLiKO mice were more susceptible to HFD-induced NASH phenotype than control mice, partly because of ER stress-induced apoptosis of hepatocytes and suppression of TG secretion from hepatocytes. This study provides evidence for the role of mitochondrial fission in the development of NASH. Graphical abstract

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Synthesis and physiological activity of heterodimers comprising different splice forms of vascular endothelial growth factor and placenta growth factor

Biochemical Journal ◽

10.1042/bj3160703 ◽

1996 ◽

Vol 316 (3) ◽

pp. 703-707 ◽

Cited By ~ 34

Author(s):

Ralf BIRKENHÄGER ◽

Bernard SCHNEPPE ◽

Wolfgang RÖCKL ◽

Jörg WILTING ◽

Herbert A. WEICH ◽

...

Keyword(s):

Endothelial Cells ◽

Growth Factor ◽

Vascular Endothelial Cells ◽

Physiological Activity ◽

Expression System ◽

Vascular Endothelial ◽

Placenta Growth Factor ◽

Splice Forms

Vascular endothilial growth factor (VEGF) and placenta growth factor (PIGF) are members of a dimeric-growth-factor family with angiogenic properties. VEGF is a highly potent and specific mitogen for endothelial cells, playing a vital role in angiogenesis in vivo. The role of PIGF is less clear. We expressed the monomeric splice forms VEGF-165, VEGF-121, PIGF-1 and PlGF-2 as unfused genes in Escherichia coli using the pCYTEXP expression system. In vitro dimerization experiments revealed that both homo- and hetero-dimers can be formed from these monomeric proteins. The dimers were tested for their ability to promote capillary growth in vivo and stimulate DNA synthesis in cultured human vascular endothelial cells. Heterodimers comprising different VEGF splice forms, or combinations of VEGF/PlGF splice forms, showed mitogenic activity. The results demonstrate that four different heterodimeric growth factors are likely to have as yet uncharacterized functions in vivo.

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Increased long noncoding RNA maternally expressed gene 3 contributes to podocyte injury induced by high glucose through regulation of mitochondrial fission

Cell Death and Disease ◽

10.1038/s41419-020-03022-7 ◽

2020 ◽

Vol 11 (9) ◽

Author(s):

Qiongxia Deng ◽

Ruowei Wen ◽

Sirui Liu ◽

Xiaoqiu Chen ◽

Shicong Song ◽

...

Keyword(s):

High Glucose ◽

Noncoding Rna ◽

Diabetic Kidney Disease ◽

Mitochondrial Fission ◽

Diabetic Mice ◽

Podocyte Injury ◽

Mitochondrial Translocation ◽

Maternally Expressed Gene 3

Abstract Excessive mitochondrial fission plays a key role in podocyte injury in diabetic kidney disease (DKD), and long noncoding RNAs (lncRNAs) are important in the development and progression of DKD. However, lncRNA regulation of mitochondrial fission in podocytes is poorly understood. Here, we studied lncRNA maternally expressed gene 3 (Meg3) in mitochondrial fission in vivo and in vitro using human podocytes and Meg3 podocyte-specific knockdown mice. Expression of lncRNA Meg3 in STZ-induced diabetic mice was higher, and correlated with the number of podocytes. Excessive mitochondrial fission of podocytes and renal histopathological and physiological parameters were improved in podocyte-specific Meg3 knockdown diabetic mice. Elongated mitochondria with attenuated podocyte damage, as well as mitochondrial translocation of dynamin-related protein 1 (Drp1), were decreased in Meg3 knockout podocytes. By contrast, increased fragmented mitochondria, podocyte injury, and Drp1 expression and phosphorylation were observed in lncRNA Meg3-overexpressing podocytes. Treatment with Mdivi1 significantly blunted more fragmented mitochondria and reduced podocyte injury in lncRNA Meg3-overexpressing podocytes. Finally, fragmented mitochondria and Drp1 mitochondrial translocation induced by high glucose were reduced following treatment with Mdivi1. Our data show that expression of Meg3 in podocytes in both human cells and diabetic mice was higher, which regulates mitochondrial fission and contributes to podocyte injury through increased Drp1 and its translocation to mitochondria.

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