Enhanced junctional epithelial permeability in TRPV4‐deficient mice

Abstract

Background and Objective As the interface between the oral cavity and the teeth, the junctional epithelial barrier is critical for gingival defense. The junctional epithelium is subject to mechanical stresses from biting force or external insults such as bacterial attacks, but little is known about the effects of mechanical stimuli on epithelial functions. Transient receptor potential vanilloid 4 (TRPV4) functions as a mechanosensitive nonselective cation channel. In the present study, based on marked expression of TRPV4 in the mouse junctional epithelium, we aimed to clarify the putative links between TRPV4 and junctional complexes in the junctional epithelium. Methods and Results Histological observations revealed that the junctional epithelium in TRPV4‐deficient (TRPV4−/−) mice had wider intercellular spaces than that in wild‐type (TRPV4+/+) mice. Exogenous tracer penetration in the junctional epithelium was greater in TRPV4−/− mice than in TRPV4+/+ mice, and immunoreactivity for adherens junction proteins was suppressed in TRPV4−/− mice compared with TRPV4+/+ mice. Analysis of a mouse periodontitis model showed greater bone volume loss in TRPV4−/− mice compared with TRPV4+/+ mice, indicating that an epithelial barrier deficiency in TRPV4−/− mice may be associated with periodontal complications. Conclusion The present findings identify a crucial role for TRPV4 in the formation of adherens junctions in the junctional epithelium, which could regulate its permeability. TRPV4 may be a candidate pharmacological target to combat periodontal diseases.

Expression and localisation of Rab44 in immune-related cells change during cell differentiation and stimulation

“…Cell culture. Isolation of BMMs was carried out according to a previously described method 20 . Briefly, bonemarrow cells from mice femurs and tibias were cultured overnight in α-MEM containing 10% foetal bovine serum (FBS), penicillin (100 U/mL) and streptomycin (100 μg/mL) at 37 °C in 5% CO 2 .…”

“…For lung and spleen staining, however, Simplestain Mouse MAX-PO (R) (Nichirei) was used in place of the secondary antibody and endogenous peroxidase treatment. Immunofluorohistochemistry of mouse bone marrow was performed as described previously 20 .…”

Junctional epithelium and hemidesmosomes: Tape and rivets for solving the “percutaneous device dilemma” in dental and other permanent implants

“…TRPV4 also contributes to cell‐cell junctions in keratinocytes through interactions with β‐catenin and E‐cadherin [ 468 ]. TRPV4-deficinent mice demonstrate wider JE intercellular spacing and greater tracer penetration ( e.g., more loosely interconnected tissue), resulting in bone loss, compared to wildtype [ 73 ]. The loss of such mechanotransduction elements may contribute to JE vulnerabilities to mechanical stresses.…”

TRPV Protein Family—From Mechanosensing to Cancer Invasion

“…TRPV4−/− mice also display drastic defects in osmoregulation [97,98]. In epithelial tissues, TRPV4 seems to be important for the maintenance of junctional permeability through its impact on adherens junction and tight junction proteins [99][100][101]. In mammary epithelial tissues, TRPV4 regulates the integrity of the cell-cell junctions specifically through the expression of tight junction proteins [102].…”