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Mechanotransduction Mechanisms of Hypertrophy and Performance with Resistance Exercise
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Andrew C. Fry, Justin X. Nicoll, Luke A. Olsen
The recruitment of mTORC1 to the lysosome may influence its activity through other mechanisms than those mentioned previously; specifically, through the lipid second messenger phosphatidic acid (PA). PA can directly activate mTORC1 through binding to its FKBP12-binding domain (184). Interestingly, phosphatidic acid increases following exercise and accumulates through the mechanosensitive properties of its upstream enzyme diacylglycerol kinase zeta (DGKζ) and phospholipase D (PLD). Indeed, the inhibition of these two enzymes attenuated mechanically driven muscle growth, while the overexpression of either PLD or DGKζ resulted in muscle hypertrophy. Moreover, PA localizes around the lysosome rendering it in close proximity to mTORC1. Outside of its ability to interact with mTORC1, PA also mediates the activity of the energy-sensing HIPPO pathway via indirect activation of yes-associated protein (YAP) through inhibition of its downstream inhibitor, long-acting thyroid stimulator (LATS) (65). Following this physical activity–induced decrease in YAP inhibition, YAP can then translocate to the nucleus, directly regulating the expression of hypertrophic genes.
Endotoxin Effects on Synthesis of Phosphatidic Acid and Phosphatidic Acid–Derived Diacylglyceride Species
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
The role of lipids, such as phosphatidylinositides (PI), diacylglycerides (DG), and phosphatidic acid (PA) species in both intracellular homeostatic and inflammatory signaling has been well established for over a decade (reviewed in Refs. 1,2), although initial evidence for the significance of PA-related signaling can be found in research from the period 1950–1955. Given that the recent reviews cited have extensively discussed mechanisms and dynamics of generalized lipid signaling in the context of PA, this chapter will center on aspects of PA and PA-related DG synthesis commensurate with inflammatory signaling that has been associated with endotoxin. The initial discussion will briefly summarize current understanding of PA and connected DG signaling, with analysis of their complex interconnections, and will include a section on the membrane effects of these lipids, which are related to some of their numerous biological activities.
Regulation of the Arachidonic Acid Cascade and PAF Metabolism in Reproductive Tissues
Published in Murray D. Mitchell, Eicosanoids in Reproduction, 2020
John M. Johnston, Noriei Maki, Marlane J. Angle, Dennis R. Hoffman
It has been proposed that in other tissues phosphatidic acid serves as a substrate for a phospholipase A2 and is involved in the release of arachidonic acid.52 We found that the phosphatidic acid content of amnion did not change prior to or during labor.16 In contrast, we found that the diacylglycerol content of amnion increased approximately twofold during the onset of early labor, from 16 to 38 mmol of diacylglycerol per mole glycerophospholipid.49
Phytic acid-modified manganese dioxide nanoparticles oligomer for magnetic resonance imaging and targeting therapy of osteosarcoma
Published in Drug Delivery, 2023
Qian Ju, Rong Huang, Ruimin Hu, Junjie Fan, Dinglin Zhang, Jun Ding, Rong Li
Aptamers (Niu et al., 2022), diphosphonate (Wu & Wan, 2012), and aspartic acid-related oligopeptides (Ogawa et al., 2017) exhibited good targeting ability to bones. However, their applications were restricted due to sophisticated synthetic methods or unpredictable biosafety. Phytic acid (PA), an organic phosphoric acid compound extracted from plant seeds, has been widely used as food additives (Zhou et al., 2019), antioxidant (Lux et al., 2022), preserving agent (Zhao et al., 2022), and chelating agent (Chen et al., 2018). PA has good biocompatibility since it was detected in mammalian cells. Interestingly, PA showed certain antitumor activities on colon tumor (Vucenik et al., 2020). PA also displayed special bone-targeting capability due to its strong chelating ability to calcium ion of bone. Consequently, PA-modified NPs was employed for targeting treatment of bone tumors (Zhou & Fan et al., 2019; Wang et al., 2020).
A review of phage mediated antibacterial applications
Published in Alexandria Journal of Medicine, 2021
Kenneth Ssekatawa, Denis K. Byarugaba, Charles D. Kato, Eddie M. Wampande, Francis Ejobi, Robert Tweyongyere, Jesca L. Nakavuma
For use as decontaminants, several studies have been conducted to evaluate the efficacy of phages as bio-control agents against food and beverage borne pathogens [20]. Phages have been experimented with in bio-sanitization of equipment surfaces to eradicate biofilms in food industries [21]; and bio-preservation of perishable processed foods to increase shelf-life. Some phage-specific enzymes; such as lysins which degrade the cell wall of gram-positive bacteria, have been applied to processed foods to enhance their safety for human consumption [18,22–24]. The use of bacteriophages in food products in the US, Europe, and Australia has been reported [25]. Indeed, some phage preparations have been approved in the USA and are commercially available; such as LISTEX P100; LMP-102TM, ListshieldTM, ECP-100TM (EcoshieldTM), SALMONELEXTM, AgriPhageTM, and Biophage-PA [26].
Blockade of PLD1 potentiates the antitumor effects of bortezomib in multiple myeloma cells by inhibiting the mTOR/NF-κB signal pathway
Published in Hematology, 2020
Yanfang Wang, Fei Dong, Wei Wan, Zhenhao Zhang, Jing Wang, Hua Wang, Xiaoyan Ke
NF-κB plays a key role in the pathogenesis of MM and is the major regulatory molecule of bortezomib against MM [25]. Increased PLD1 activity could activate various molecular pathways such as the mTOR, Ras-ERK-PI3 K, and Wnt/β-catenin signaling to promote tumor cell proliferation and cell cycle progression [14–17]. In this study, we found that the expressions of both mTOR and NF-κB were significantly decreased when the PLD1-specific inhibitor was combined with bortezomib. Previous reports revealed that Akt activation and NF-κB nuclear translocation could be significantly inhibited by the knockdown of the mTORC2 protein [33], and the activation of mTOR in pulmonary epithelial cells promoted acute lung injury through the downregulation of autophagy and subsequent activation of NF-κB [34]. In addition, phosphatidic acid (PA) is the metabolic product of PLD1 and can bind and activate the mTORC1 as well as of mTORC2 complexes, which could also phosphorylate Akt [35]. NF-κB is a well-known target protein of the PI3K/Akt signaling pathway. Therefore, the absence of PLD1 could impair the activation of the mTOR complex and lead to a defective Akt/NF-κB activation. Our results confirmed that the mTOR activator MHY1485 could counteract the chemosensitizing effect of the PLD1 inhibitor by increasing the expressions of mTOR and NF-κB and promoting MM cell proliferation.