Superparamagnetic Contrast Agents
Michel M. J. Modo, Jeff W. M. Bulte in Molecular and Cellular MR Imaging, 2007
Internalization of foreign materials by cells has classically been divided into uptake of large materials (phagocytosis) and uptake of soluble materials or nanoparticles (pinocytosis). Pinocytosis can be further divided into clathrin-dependent fluid-phase endocytosis and macropinocytosis. Phagocytosis and receptor-mediated endocytosis share many characteristics, although the extent of overlap between these processes has not been fully described. Using uncoated polystyrene in the size range of 100 to 1000 nm, no apparent size-related discontinuity was observed between pinocytic and phagocytic uptake by rat peritoneal macrophages.66 Since iron oxide nanoparticles have hydrodynamic diameters between 9 and 180 nm, pinocytosis is mainly involved (Figure 4.3).
Gastrointestinal Tract as a Major Route of Pharmaceutical Administration
Shayne C. Gad in Toxicology of the Gastrointestinal Tract, 2018
Pinocytosis is Greek for “cell drinking” and involves the plasma membrane invaginating a volume of extracellular fluid and anything it contains including water, salts, biochemicals, and even soluble macromolecules. In this type of endocytosis which is also termed “fluid endocytosis” and “bulk-phase pinocytosis,” small particles suspended in extracellular fluid are brought into the cell through an invagination of the cell membrane, resulting in a suspension of the particles within a vesicle inside the cell. These pinocytotic vesicles fuse with lysosomes to hydrolyze the particles. The invagination and subsequent restructuring of the cell wall require energy (Stillwell, 2016). Pinocytosis is used primarily for clearing extracellular fluids and as part of immune surveillance (Kruth, 2011; Abbas et al., 2016).
Antiviral Nanomaterials as Potential Targets for Malaria Prevention and Treatment
Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji in Viral and Antiviral Nanomaterials, 2022
Pinocytosis is classified as caveolae-mediated endocytosis, clathrin-mediated endocytosis clathrin- and caveolae-independent endocytosis, and micropinocytosis (Sun et al. 2019) (Table 18.2). Caveolar-mediated endocytosis is a clathrin-independent endocytotic mechanism involving bulb-shaped caveolae. Caveolae are 50-60 nm plasma membrane invaginations. Caveolae are formed by caveolins, which are integral membrane proteins, and cavins are peripheral membrane proteins. Clathrin-mediated endocytosis possesses complex protein machinery that transiently assembles on the plasma membrane and creates clathrin-coated endocytic vesicles. This machinery selects and concentrates cargo molecules and shapes the membrane into a vesicle.
Improved delivery of natural alkaloids into lung cancer through woody oil-based emulsive nanosystems
Published in Drug Delivery, 2018
Jing Zhao, Shan Liu, Xueyuan Hu, Yunmei Zhang, Shenglei Yan, Hua Zhao, Mei Zeng, Yao Li, Lan Yang, Jingqing Zhang
The cellular uptake of EFEN by tumor cells was a dose-dependent and time-dependent process over 12 h. Furthermore, it was an energy-dependent process since much more EFEN was taken into cells at body temperature than at lower temperature. Pinocytosis refers to a process in which liquid droplets are ingested by living cells. Since it is in the fluid state, EFEN might be taken into tumor cells via pinocytosis. Chlorpromazine is a clathrin-mediated pathway inhibitor, while genistein is both caveolae-dependent and clathrin-independent pathway inhibitor. Chlorpromazine and genistein were separately applied to investigate the transport proteins involved in the endocytosis procedure. The decreased uptaken amount of tumor cells after adding two inhibitors suggested that NFEN was trafficked through three pinocytosis pathways: clathrin-mediated, caveolae-dependent, and clathrin-independent pathways. This is consistent with previous reports that microbubbles induced clathrin-mediated endocytosis and fluid-phase uptake through distinct mechanisms (Fekri et al., 2016) and that doxorubicin-conjugated poly(methacrylic acid-co-cholesteryl methacrylate) copolymers were internalized through both clathrin-dependent and clathrin-independent endocytosis mechanisms (Sevimli et al., 2015). However, octanoyl galactose ester-modified microemulsion systems containing coix seed components were reported to improve accumulation in tumors through asialoglycoprotein receptor-mediated endocytosis (Qu et al., 2017).
Protein transduction domain of translationally controlled tumor protein: characterization and application in drug delivery
Published in Drug Delivery, 2022
Endocytosis is largely classified as a two part process that includes phagocytosis and pinocytosis. Pinocytosis, the uptake of fluid and solute by the cell, occurs in all types of cells through four pathways including (i) clathrin-mediated, (ii) caveolae-mediated, (iii) clathrin, caveolae-independent pathway, and (iv) macropinocytosis (Conner & Schmid, 2003). Clathrin-mediated endocytosis (CME) is a clathrin/dynamin-dependent, receptor-mediated process and this pathway is reported to operate in the cases of TAT-PTD, oligoarginine, and anionic PTDs (Ruseska & Zimmer, 2020). Binding of ligand to a specific receptor on the cell membrane induces the assembly of clathrins in a polyhedral lattice, followed by the invagination of clathrin-coated membrane surface (Ruseska & Zimmer, 2020). Caveolae-mediated endocytosis (CvME) is mediated by the formation of caveolae, a highly hydrophobic membrane domain rich in sphingolipid and cholesterol (Ruseska & Zimmer, 2020) and is reported to occur with TAT fusion protein, transportan and proline-rich PTDs. Actin cytoskeleton and cholesterol are the essential elements for caveolae formation and dynamin, a multidomain GTPase, constricts the neck of caveolae for enabling its release (Ruseska & Zimmer, 2020).
Enhanced toxicity of 2,2-bis(chloromethyl) trimethylene bis[bis(2-chloroethyl) phosphate] (V6) by nanopolystyrene particles towards HeLa cells
Published in Nanotoxicology, 2023
Zheng Zhong, Xin Liu, Yiming Ruan, Ziwei Li, Junxian Li, Lili Sun, Sen Hou
Several cellular uptake pathways have been reported concerning with the entrance of particles into the cells. Small particles with a size ranging from a few nanometers to hundreds of nanometers are capable to be internalized by pinocytosis (Behzadi et al. 2017). Pinocytosis can be classified into four categories: clathrin-mediated endocytosis, caveolae-mediated endocytosis, clathrin and caveolae-independent endocytosis, and micropinocytosis (Zhao et al. 2011). Lai et. al (Lai et al. 2007) have found that NPs smaller than 25 nm reach the perinuclear region of the HeLa cells via non-degradative vesicle. This pathway is non-clathrin-mediated, non-caveolae-mediated and cholesterol-independent. While NPs between 25 nm and 44 nm entered HeLa cells primarily via clathrin-mediated endocytosis pathway.
Related Knowledge Centers
- Cell Biology
- Endosome
- Extracellular Fluid
- Hydrolysis
- Invagination
- Vesicle
- Cell Membrane
- Lipid
- Phagocytosis
- Endocytosis