Effect of fluid shear stress on in vitro cultured ureteric bud cells.

Hiroshi Kimura,Takehiko Ogawa,Lifu Zhao,Norimoto Yanagawa,Oak D Jo,Naomi Yanagawa,Masaki Nishikawa,Shunsuke Miyamoto,Morgan Hamon,Hiroko Nakamura,Mitsuru Komeya,Peter Hauser

doi:10.1063/1.5035328

Hiroshi Kimura, Takehiko Ogawa + Show 10 more

Open Access

https://doi.org/10.1063/1.5035328

Copy DOI

Abstract

Most kidney cells are continuously exposed to fluid shear stress (FSS) from either blood flow or urine flow. Recent studies suggest that changes in FSS could contribute to the function and injury of these kidney cells. However, it is unclear whether FSS influences kidney development when urinary flow starts in the embryonic kidneys. In this study, we evaluated the influence of FSS on in vitro cultured ureteric bud (UB) cells by using a pumpless microfluidic device, which offers the convenience of conducting parallel cell culture experiments while also eliminating the need for cumbersome electronic driven equipment and intricate techniques. We first validated the function of the device by both mathematical model and experimental measurements. UB cells dissected from E15.5 mouse embryonic kidneys were cultured in the pumpless microfluidic device and subjected to FSS in the range of 0.4–0.6 dyn mm−2 for 48 h (dynamic). Control UB cells were similarly cultured in the device and maintained under a no-flow condition (static). We found from our present study that the exposure to FSS for up to 48 h led to an increase in mRNA expression levels of UB tip cell marker genes (Wnt11, Ret, Etv4) with a decrease in stalk cell marker genes (Wnt7b, Tacstd2). In further support of the enrichment of UB tip cell population in response to FSS, we also found that exposure to FSS led to a remarkable reduction in the binding of lectin Dolichos Biflorus Agglutinin. In conclusion, results of our present study show that exposure to FSS led to an enrichment in UB tip cell populations, which could contribute to the development and function of the embryonic kidney when urine flow starts at around embryonic age E15.5 in mouse. Since UB tip cells are known to be the proliferative progenitor cells that contribute to the branching morphogenesis of the collecting system in the kidney, our finding could imply an important link between the FSS from the initiation of urine flow and the development and function of the kidney.

Highlights

It is well known that fluid shear stress (FSS) influences cell functions such as alignment, migration, differentiation, and phenotypic expression.1 In the kidney, there are two types of fluid flows, i.e., blood flow and urine flow
Results of our present study show that exposure to FSS led to an enrichment in ureteric bud (UB) tip cell populations, which could contribute to the development and function of the embryonic kidney when urine flow starts at around embryonic age E15.5 in mouse
With UB cells cultured in this device, we found that exposure to FSS promoted the enrichment of UB tip cells, as reflected by an increase in mRNA expression of tip cell marker genes, as well as a decrease in Dolichos Biflorus Agglutinin (DBA) binding

Summary

Introduction

It is well known that fluid shear stress (FSS) influences cell functions such as alignment, migration, differentiation, and phenotypic expression. In the kidney, there are two types of fluid flows, i.e., blood flow and urine flow. It is well known that fluid shear stress (FSS) influences cell functions such as alignment, migration, differentiation, and phenotypic expression.. It is conceivable that FSS may affect the functions of kidney cells and play a role in various kidney diseases.. Microfluidic technology has been widely used to study the effect of FSS on kidney cells.. Microfluidic technology has been widely used to study the effect of FSS on kidney cells.1,4–6 These studies showed that exposure to FSS in the range of 0.2–5.0 dyn cmÀ2 that mimicks the in vivo condition had significant effects on kidney cell morphology, such as orientation, thickness, and cilia formation, and kidney cell functions, such as albumin transport, glucose reabsorption, and alkaline phosphatase activity.. Microfluidic technology has been widely used to study the effect of FSS on kidney cells. These studies showed that exposure to FSS in the range of 0.2–5.0 dyn cmÀ2 that mimicks the in vivo condition had significant effects on kidney cell morphology, such as orientation, thickness, and cilia formation, and kidney cell functions, such as albumin transport, glucose reabsorption, and alkaline phosphatase activity. On the other hand, higher levels of FSS were found to cause marked reduction in cell viability and reduced levels of urokinase release.

Methods

Results

Conclusion