Human mammary epithelial cells in a mature, stratified epithelial layer flatten and stiffen compared to single and confluent cells.
Actin
Atomic force microscopy
Human mammary epithelial cells
Mature layer
Stiffness
Journal
Biochimica et biophysica acta. General subjects
ISSN: 1872-8006
Titre abrégé: Biochim Biophys Acta Gen Subj
Pays: Netherlands
ID NLM: 101731726
Informations de publication
Date de publication:
06 2021
06 2021
Historique:
received:
08
10
2020
revised:
07
02
2021
accepted:
03
03
2021
pubmed:
11
3
2021
medline:
11
9
2021
entrez:
10
3
2021
Statut:
ppublish
Résumé
The epithelium forms a protective barrier against external biological, chemical and physical insults. So far, AFM-based, micro-mechanical measurements have only been performed on single cells and confluent cells, but not yet on cells in mature layers. Using a combination of atomic force, fluorescence and confocal microscopy, we determined the changes in stiffness, morphology and actin distribution of human mammary epithelial cells (HMECs) as they transition from single cells to confluency to a mature layer. Single HMECs have a tall, round (planoconvex) morphology, have actin stress fibers at the base, have diffuse cortical actin, and have a stiffness of 1 kPa. Confluent HMECs start to become flatter, basal actin stress fibers start to disappear, and actin accumulates laterally where cells abut. Overall stiffness is still 1 kPa with two-fold higher stiffness in the abutting regions. As HMECs mature and form multilayered structures, cells on apical surfaces become flatter (apically more level), wider, and seven times stiffer (mean, 7 kPa) than single and confluent cells. The main drivers of these changes are actin filaments, as cells show strong actin accumulation in the regions where cells adjoin, and in the apical regions. HMECs stiffen, flatten and redistribute actin upon transiting from single cells to mature, confluent layers. Our findings advance the understanding of breast ductal morphogenesis and mechanical homeostasis.
Sections du résumé
BACKGROUND
The epithelium forms a protective barrier against external biological, chemical and physical insults. So far, AFM-based, micro-mechanical measurements have only been performed on single cells and confluent cells, but not yet on cells in mature layers.
METHODS
Using a combination of atomic force, fluorescence and confocal microscopy, we determined the changes in stiffness, morphology and actin distribution of human mammary epithelial cells (HMECs) as they transition from single cells to confluency to a mature layer.
RESULTS
Single HMECs have a tall, round (planoconvex) morphology, have actin stress fibers at the base, have diffuse cortical actin, and have a stiffness of 1 kPa. Confluent HMECs start to become flatter, basal actin stress fibers start to disappear, and actin accumulates laterally where cells abut. Overall stiffness is still 1 kPa with two-fold higher stiffness in the abutting regions. As HMECs mature and form multilayered structures, cells on apical surfaces become flatter (apically more level), wider, and seven times stiffer (mean, 7 kPa) than single and confluent cells. The main drivers of these changes are actin filaments, as cells show strong actin accumulation in the regions where cells adjoin, and in the apical regions.
CONCLUSIONS
HMECs stiffen, flatten and redistribute actin upon transiting from single cells to mature, confluent layers.
GENERAL SIGNIFICANCE
Our findings advance the understanding of breast ductal morphogenesis and mechanical homeostasis.
Identifiants
pubmed: 33689830
pii: S0304-4165(21)00049-0
doi: 10.1016/j.bbagen.2021.129891
pmc: PMC8052296
mid: NIHMS1684365
pii:
doi:
Types de publication
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
129891Subventions
Organisme : NHLBI NIH HHS
ID : R15 HL148842
Pays : United States
Informations de copyright
Copyright © 2021 Elsevier B.V. All rights reserved.
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