Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum

Cells respond to extracellular mechanical forces through the assembly of integrin adhesion complexes (IACs) that provide a scaffold through which cells sense and transduce responses to those forces. IACs are composed of transmembrane integrin receptors that bind to extracellular matrix (ECM) protein...

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Main Authors: Bryan A. McLendon, Avery C. Kramer, Heewon Seo, Fuller W. Bazer, Robert C. Burghardt, Gregory A. Johnson
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:Biology
Subjects:
Online Access:https://www.mdpi.com/2079-7737/10/6/508
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author Bryan A. McLendon
Avery C. Kramer
Heewon Seo
Fuller W. Bazer
Robert C. Burghardt
Gregory A. Johnson
author_facet Bryan A. McLendon
Avery C. Kramer
Heewon Seo
Fuller W. Bazer
Robert C. Burghardt
Gregory A. Johnson
author_sort Bryan A. McLendon
collection DOAJ
description Cells respond to extracellular mechanical forces through the assembly of integrin adhesion complexes (IACs) that provide a scaffold through which cells sense and transduce responses to those forces. IACs are composed of transmembrane integrin receptors that bind to extracellular matrix (ECM) proteins externally and connect with the actomyosin cytoskeleton internally. Myometrial smooth muscle cells respond to forces that arise due to increases in fetal growth/weight, placental fluid volumes, and blood flow. As a result, the uterus transforms into an organ that can forcefully expel the fetus and placental membranes during parturition. While earlier studies focused on IAC expression in the myometrial compartment of rodents and humans to explore pregnancy-associated responses, the present study examines IAC assembly in ovine myometrium where mechanical forces are expected to be amplified in a manner similar to humans. Results indicate that the ITGA5 and ITGB1 heterodimers associate with the ECM protein FN1 externally, and with VCL and TLN1 internally, to form IACs in myometrial cells during the first trimester of pregnancy. These IACs become increasingly ordered until parturition. This ordered structure is lost by one day postpartum; however, the abundance of the integrin proteins remains elevated for at least two weeks postpartum. Implications of the present study are that sheep are similar to humans regarding the assembly of IACs in the pregnant myometrium and suggest that IACs may form much earlier in human gestation than was previously implied by the rat model. Results highlight the continued value of the sheep model as a flagship gynecological model for understanding parturition in humans.
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spelling doaj.art-10619b29aea645c4ac8ef9b43142431c2023-11-21T23:12:17ZengMDPI AGBiology2079-77372021-06-0110650810.3390/biology10060508Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and PostpartumBryan A. McLendon0Avery C. Kramer1Heewon Seo2Fuller W. Bazer3Robert C. Burghardt4Gregory A. Johnson5Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USADepartment of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USADepartment of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USADepartment of Animal Science, Texas A&M University, College Station, TX 77843, USADepartment of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USADepartment of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USACells respond to extracellular mechanical forces through the assembly of integrin adhesion complexes (IACs) that provide a scaffold through which cells sense and transduce responses to those forces. IACs are composed of transmembrane integrin receptors that bind to extracellular matrix (ECM) proteins externally and connect with the actomyosin cytoskeleton internally. Myometrial smooth muscle cells respond to forces that arise due to increases in fetal growth/weight, placental fluid volumes, and blood flow. As a result, the uterus transforms into an organ that can forcefully expel the fetus and placental membranes during parturition. While earlier studies focused on IAC expression in the myometrial compartment of rodents and humans to explore pregnancy-associated responses, the present study examines IAC assembly in ovine myometrium where mechanical forces are expected to be amplified in a manner similar to humans. Results indicate that the ITGA5 and ITGB1 heterodimers associate with the ECM protein FN1 externally, and with VCL and TLN1 internally, to form IACs in myometrial cells during the first trimester of pregnancy. These IACs become increasingly ordered until parturition. This ordered structure is lost by one day postpartum; however, the abundance of the integrin proteins remains elevated for at least two weeks postpartum. Implications of the present study are that sheep are similar to humans regarding the assembly of IACs in the pregnant myometrium and suggest that IACs may form much earlier in human gestation than was previously implied by the rat model. Results highlight the continued value of the sheep model as a flagship gynecological model for understanding parturition in humans.https://www.mdpi.com/2079-7737/10/6/508integrin adhesion complex (IAC)mechanosensation/mechanotransductionmyometriumpregnancysheep
spellingShingle Bryan A. McLendon
Avery C. Kramer
Heewon Seo
Fuller W. Bazer
Robert C. Burghardt
Gregory A. Johnson
Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
Biology
integrin adhesion complex (IAC)
mechanosensation/mechanotransduction
myometrium
pregnancy
sheep
title Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
title_full Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
title_fullStr Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
title_full_unstemmed Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
title_short Integrin Adhesion Complex Organization in Sheep Myometrium Reflects Changing Mechanical Forces during Pregnancy and Postpartum
title_sort integrin adhesion complex organization in sheep myometrium reflects changing mechanical forces during pregnancy and postpartum
topic integrin adhesion complex (IAC)
mechanosensation/mechanotransduction
myometrium
pregnancy
sheep
url https://www.mdpi.com/2079-7737/10/6/508
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