Related Experiment Video

Updated: Sep 9, 2025

Visualizing Membrane Ruffle Formation using Scanning Electron Microscopy
08:05

Visualizing Membrane Ruffle Formation using Scanning Electron Microscopy

Published on: May 27, 2021

2.7K

AntimiR uptake by human proximal tubule epithelial cells is predominantly by macropinocytosis

Emily K Glover1, Rolando Berlinguer-Palmini2, Emily R Thompson3

  • 1Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK. emily.glover@newcastle.ac.uk.

Scientific Reports
|August 28, 2025
PubMed

Insights

MicroRNA inhibitors (antimiRs) can be delivered to human kidney cells in vitro without transfection agents. Macropinocytosis is the primary pathway for antimiR uptake by proximal tubule epithelial cells.

Area of Science:

  • Biomedical Science
  • Molecular Biology
  • Renal Medicine

Background:

  • MicroRNA inhibitors (antimiRs) show therapeutic potential for kidney diseases, such as ischemia-reperfusion injury.
  • Efficient delivery of antimiRs to target kidney cells remains a challenge.
  • Previous studies suggest endocytic uptake of antimiRs in ex-situ kidney perfusion models.

Purpose of the Study:

  • To investigate in vitro antimiR uptake by primary human proximal tubule epithelial cells (PTEC).
  • To identify the specific endocytic mechanism responsible for antimiR entry into PTEC.
  • To determine if transfection reagents are required for antimiR delivery to PTEC in vitro.

Main Methods:

  • Primary human PTEC were isolated from donor kidneys and cultured.
  • AntimiR uptake was assessed by fluorescence microscopy and quantification of fluorescent signals.
  • Endocytosis was confirmed using endocytic markers and temperature-dependent uptake assays.
  • Specific endocytic pathways were investigated using inhibitors for receptor-mediated endocytosis (megalin) and macropinocytosis.

Main Results:

  • PTEC demonstrated significant uptake of fluorescently labeled antimiRs in vitro.
  • Uptake exhibited a vesicular pattern, consistent with endocytosis.
  • AntimiR uptake was dependent on temperature and co-localized with endocytic markers.
  • Inhibition of macropinocytosis significantly reduced antimiR uptake, while megalin inhibition had no effect.

Conclusions:

  • AntimiRs can be effectively delivered to primary human PTEC in vitro without the need for transfection reagents.
  • Macropinocytosis is the predominant endocytic pathway for antimiR entry into PTEC.
  • These findings support the potential for non-viral antimiR delivery strategies in treating kidney diseases.
Keywords:
AntimiREndocytosisMacropinocytosisProximal tubule epithelial cellsTraffickingantimiR

More Related Videos

Automated Imaging and Analysis for the Quantification of Fluorescently Labeled Macropinosomes11:01

Automated Imaging and Analysis for the Quantification of Fluorescently Labeled Macropinosomes

Published on: August 24, 2021

2.9K
Fluorescence Microscopy for ATP Internalization Mediated by Macropinocytosis in Human Tumor Cells and Tumor-xenografted Mice08:31

Fluorescence Microscopy for ATP Internalization Mediated by Macropinocytosis in Human Tumor Cells and Tumor-xenografted Mice

Published on: June 30, 2021

2.9K

Related Concept Videos

Carrier-Mediated Transport01:06

Carrier-Mediated Transport

Carrier-mediated transport is a pivotal process in drug absorption, particularly for lipid-insoluble drugs, and encompasses facilitated diffusion and active transport. Facilitated diffusion allows drugs to move along their concentration gradient without energy expenditure, while active transport utilizes ATP to drive drug movement against this gradient.
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
541
Drug Elimination by Renal Route: Tubular Secretion01:15

Drug Elimination by Renal Route: Tubular Secretion

Once the process of glomerular filtration is completed, blood carrying unfiltered drug molecules traverses through efferent arterioles and makes its way into the peritubular capillaries in the proximal tubule. A variety of carriers play a pivotal role in actively secreting drugs from these peritubular capillaries into the tubular fluid. The organic anion transporter transfers acidic drugs, against an electrochemical gradient, from the peritubular capillaries into the renal tubule cells and...
2.5K
Mechanisms of Drug Absorption: Paracellular, Transcellular, and Vesicular Transport01:23

Mechanisms of Drug Absorption: Paracellular, Transcellular, and Vesicular Transport

Drugs need to permeate cell membranes to reach their target sites after administration. Orally administered drugs must transcend intestinal epithelial membrane barriers to infiltrate the systemic circulation. Drugs with a molecular weight of less than 500 Daltons diffuse through gaps between neighboring cells, called paracellular pathways.
However, most drugs use the transcellular route, traversing directly through the cell membranes via two mechanisms: passive and active transport. Passive...
788
Pinocytosis00:38

Pinocytosis

Cells use energy-requiring bulk transport mechanisms to transfer large particles or large numbers of small particles into or out of the cell. The cells envelop the particles in spherical membranes called vesicles or vacuoles. Vesicles that transport material into the cell are built from the cell membrane. These vesicles encapsulate external molecules and transport them into the cell in a process called endocytosis.
Pinocytosis ("cellular drinking") is one of three main types of...
3.4K
Pore Transport and Ion-Pair Transport01:17

Pore Transport and Ion-Pair Transport

Pore transport and ion-pair formation are critical mechanisms for the absorption and distribution of drugs in the body.
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited  but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
635
Glucose Absorption Into the Small Intestine01:26

Glucose Absorption Into the Small Intestine

Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and...
32.3K